Title of Invention	"A METHOD FOR THE PRODUCTION OF A CEMENT DISPERSANT AND A METHOD OF PRODUCING CONCRETE"
Abstract	A method for the production of a cement dispersant comprising water-soluble vinyl copolymers, in which the water-soluble vinyl copolymers is obtained by radical copolymerization of a mixture of a vinyl monomer to form Unit A, a vinyl monomer to form Unit B, a vinyl monomer to form Unit C, and a vinyl monomer to form Unit D in the presence of a radical initiator in an aqueous solution, the obtained water-soluble vinyl copolymers having 40 to 80 molar % of the Unit A, 0.5 to 20 molar % of the Unit B, 0.2 to 18 molar % of the Unit C and 2 to 40 molar % of the Unit D, the total content of the Units A, B, C and D being 100 molar %, pullulan-converted weight-average molecular weight measured by Gel Permeation Chromatography Method of the water-soluble vinyl copolymers being 15000 to 150000 and the ratio of the weight-average molecular weight to number-average molecular weight being 2 to 7. Unit A can be formed by sodium salt of acrylic acid. Unit B can be formed by sodium salt of methallyl sulfonic acid. Unit C can be formed by methyl acrylate. Unit D can be formed by methoxy polyethylene glycol methacrylate with oxyalkylene units including only oxyethylene units and their repetition number in the range of 26 to 95.

Title of Invention

"A METHOD FOR THE PRODUCTION OF A CEMENT DISPERSANT AND A METHOD OF PRODUCING CONCRETE"

Abstract

A method for the production of a cement dispersant comprising water-soluble vinyl copolymers, in which the water-soluble vinyl copolymers is obtained by radical copolymerization of a mixture of a vinyl monomer to form Unit A, a vinyl monomer to form Unit B, a vinyl monomer to form Unit C, and a vinyl monomer to form Unit D in the presence of a radical initiator in an aqueous solution, the obtained water-soluble vinyl copolymers having 40 to 80 molar % of the Unit A, 0.5 to 20 molar % of the Unit B, 0.2 to 18 molar % of the Unit C and 2 to 40 molar % of the Unit D, the total content of the Units A, B, C and D being 100 molar %, pullulan-converted weight-average molecular weight measured by Gel Permeation Chromatography Method of the water-soluble vinyl copolymers being 15000 to 150000 and the ratio of the weight-average molecular weight to number-average molecular weight being 2 to 7. Unit A can be formed by sodium salt of acrylic acid. Unit B can be formed by sodium salt of methallyl sulfonic acid. Unit C can be formed by methyl acrylate. Unit D can be formed by methoxy polyethylene glycol methacrylate with oxyalkylene units including only oxyethylene units and their repetition number in the range of 26 to 95.

Full Text	1A Field of invention : This invention relates to a method for the production of a cement dispersant and a method of producing concrete. At work sites where cement compositions are used, it is important to be able to provide high fluidity to cement compositions, to reduce the drop in the proyided fluidity with time ("the slump loss") and to obtain a sufficient early strength during the initial period of hardening such that the frames can be removed quickly and the work efficiency can be thereby improved. This invention relates to cement dispersants which can respond to such requirements, as well as methods of using such cement dispersants to produce concrete with improved quality. This invention also relates to concrete produced by using such a cement dispersant. Examples of prior art cement dispersant for providing fluidity to cement compositions include salts of high condensates of naphthalene sulfonic acid formaldehyde and melamine sulfonic acid formaldehyde, as well as water-soluble vinyl copolymers. Cement compositions prepared by using salts of high condensates of naphthalene sulfonic acid formaldehyde or melamine sulfonic acid formaldehyde, however, have the problem of a high slump loss. Those prepared by using water-soluble vinyl copolymers of the conventionally proposed kind (such as disclosed in Japanese Patent Publications Tokko 58-38380, 59-18338 and 5-11057 and U.S. Patents 4 962 173, 5 087 648, 5 290 869 and 5 362 829 ) have smaller slump losses but there are problems wherein their setting times become longer and hence a sufficient early strength cannot be obtained during the early period of hardening. This problem is particularly significant with high-strength cement compositions with a limited water-to-cement ratio. 2 Summary of the Invention The problem to be overcome by the present invention is that prior art cement dispersants could produce only cement compositions with a large slump loss or incapable of providing a sufficiently large early strength, this problem being particularly significant with high-strength cement compositions with a limited water-to-cement ratio. The present invention was accomplished as a result of investigations by the present inventors and is based on their discovery that water-soluble vinyl copolymers constituting of specified kinds of constituent units (herein referred to simply as "units") at a specified ratio and having both the weight average molecular weight and the ratios between the weight average molecular weight and the number average molecular weight within a specified range are suitable as a cement dispersant. Detailed Description of the Invention : This invention provides a method for the production of a cement dispersant comprising of water-soluble vinyl copolymers, in which the water-soluble vinyl copolymers is obtained by radical copolymerization of a mixture of a vinyl monomer to form Unit A having Formula (1), a vinyl monomer to form Unit B having Formula (2), a vinyl monomer to form Unit C having Formula (3) and a vinyl monomer to form Unit D having Formula (4) in the presence of a radical initiator in an aqueous solution, the obtained water-soluble vinyl copolymers having 40 to 80 molar % of the Unit A, 0.5 to 20 molar % of the Unit B, 0.2 to 18 molar % of the Unit C and 2 to 40 molar % of the Unit D, the total content of the Units A, B, C and D being 100 molar %, pullulan-converted weight-average molecular weight measured by Gel Permeation Chromatography (GPC) Method of the water-soluble vinyl copolymers being 15000 to 150000 and the ratio of the 2A weight-average molecular weight to number-average molecular weight being 2 to 7, said Formulas (1) to (4) being given by - 3 where R\ R2 and R3 are each H or CH3, R4 is H or an alkyl group with 1 to 3 carbon atoms, X is a group having Formula (5) or (6), said Formulas being given by - -SO3M2 (Formufa 5) -O-C6H4-SO3M3 (Formula 6) A is a residual group obtainable by removing a!! hydroxyl groups from polyether dio! with repetition number of oxyalkylene units being 5 to 109, the oxyalkylene units consisting either only of oxyethylene units or of both oxyethylene and oxypropylene units, M1 is H, an alkali metal, an alkali earth metal, ammonium or an organic amine, and M2 and M3 are each an alkali metal, an alkali earth metal, ammonium or an organic amine. Cement dispersants of this invention are a water-soluble vinyl copolymers having four constituent units described above but those having as Unit D both Unit E shown below by by Formula (7) and Unit F shown below by Formula (8) are preferred: {Formula 7) 3A (Formula 8) where R5 is H or CH3l R6 is an alkyl group with 1 to 3 carbon atoms, n is an integer of 40 to 109 and m is an integer of 5 to 25. In other words, preferred kinds of water-soluble vinyl copolymers according to this invention include not only Units A, B and C shown by Formulas (1), (2) and (3) but also a relatively long polyoxyethylene graft chain due to Unit E of Formula (7) and a relatively short chain polyoxyethylene graft chain. These constituent Units A, B, C and D, or Units A, B, C, E and F in the case of an aforementioned preferred example, can all be formed by copolymerizing corresponding vinyl monomers. Examples of vinyl monomers which form Unit A shown by Formula (1) include (1) (meth)acrylicacid, and (2) alkali metal salts, alkali earth metal salts and organic amine salts of (meth)acrylic acid. Of these, alkali metal salts such as sodium and potassium salts of (meth)acryNc acid are prefered. Examples of vinyl monomers which form Unit B shown by Formula (2) include (1) alkali metal salts, alkali earth metal salts and organic amine salts of methallyl sulfonic acid, and (2) alkali metal salts, alkali earth metal salts and organic amine salts of p-methallyl oxybenzene 4 sulfonic acid. Of these, alkali metal salts such as sodium and potassium salts of methallyl sulfonic acid are preferred. Examples of vinyl monomers which form Unit C shown by Formula (3) include methyl acrylate and methyl methacrylate. Of these, methyl acrylate is preferred. Examples of vinyl monomers which form Unit D shown by Formula (4) include (1) alkoxy polyoxyalkylene giycol (meth)acrylate with 1-3 carbon atoms and (2) polyoxyalkylene glycol mono(meth)acrylate1 both with repetition number of oxyalkylene units 5-109. Examples of (1) above include methoxy polyethylene glycol (meth)acrylate, methoxy polyethylene glycol polypropylene glycol (meth)acrylate, methoxy polypropylene glycol (meth)acrylate,, ethoxy polyethylene glycol (meth)acrylate, ethoxy polyethylene glycol polypropylene glycol (meth)acrylate, ethoxy polypropylene glycol (meth)acrylate, n-propoxy polyethylene glycol (meth)acrylate, n-propoxy polyethylene glycol polypropylene glycol (meth)acrylate, isopropoxy polyethylene glycol mono(meth)acrylate, and isopropoxy polyethylene glycol polypropylene glycol (meth)acrylate. Examples of (2) above include polyoxyalkylene glycol mono(meth)acrylates such as polyethylene glycol mono(meth)acrylate, polyethylene glycol polypropylene glycol mono(meth)acrylate, and polypropylene glycol mono(meth)acrylate. Of these, methoxy polyethylene glycol methacrylate and polyethylene glycol monomethacrylate with oxyalkylene units including only oxyethylene units and their repetition number in the range of 26-95 are preferred. Examples of vinyl monomers which form Unit E shown by Formula (7) include alkoxy polyethoxyethyl (meth)acrylates with 1-3 carbon atoms and the repetition number of oxyethylene units in the range of 40-109 such as methoxy polyethoxyethyl (meth)acrylate, ethoxypolyethoxyethyl (meth)acrylate, n-propoxy polyethoxyethyl (meth)acrylate, and isopropoxy polyethoxyethyl (meth)acrylate. Of these, methoxy polyethoxyethyl methacrylates with the repetition number of oxyethylene units in the range of 55-100 are preferred. Examples of vinyl monomers which form Unit F shown by Formula (8) include methoxy polyethoxyethyl methacrylates with the repetition number of oxyethylene units in the range of 5-25. Of these, methoxy polyethoxyethyl methacrylates with the repetition number of oxyethylene units in the range of 7-23 are preferred. Water-soluble vinyl copolymers to be used as a cement dispersant according to this invention may be obtained by radical copofymerization of vinyl monomers forming Units A-D, or preferably Units A, B, C, E and F at a specified copolymerization ratio in the presence of a radical initiator. The radical copolymerization can be carried out by aqueous solution polymerization using water or a mixed solvent with water and a water-soluble organic solvent either continuously or by batches. For example, each of the vinyl monomers is initially dissolved in water to prepare an aqueous solution with pH 4.5-6.5 containing these vinyl monomers by 10-40 weight % as their 5 total. Next, a radical initiator is added to this aqueous solution within a nitrogen gas atmosphere to carry out a radical copolymerization reaction at 50-70°C for 5-8 hours and to thereby obtain water-soluble vinyl copolymer. Any radical initiator which generates radicals by decomposing at the reaction temperature of copolymerization may be used for the copolymerization reaction of either of the vinyl monomers, but the use of a water-soluble radical initiator is preferred. Examples of such water-soluble radical initiator include persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide, and 2,2-azobis (2-amidinopropane) dihydrochloride. They may be combined with a reducing agent such as a sulfite and L-ascorbic acid or amines to be used as a redox initiator. As described above, water-soluble vinyl copolymers to be used as a cement dispersant according to this invention are characterized as comprising Units A-D, or preferably Units A, B, C, E and F at a specified ratio, but they are also required to have the weight average molecular weight (pullulan converted by GPC method) and the ratio of weight average molecular weight to number average molecular weight (hereinafter denoted as Mw/Mn) within specified ranges. Adjustment of such molecular weight distributions can be effected by a conventional method of appropriately controlling concentrations of the vinyl monomers in the system for radical copolymerization, the pH of the polymerizing system, its temperature and the addition of a chain transfer agent. In order to obtain a water-soluble vinyl copolymer with a desired molecular weight distribution, it is preferred to set the pH value of the polymerizing system at 4.0-6.5 and to add a chain transfer agent such as 2-mercapto ethanol, 2-mercapto propionic acid, 3-mercapto propionic acid, thioglycol acid and thioglycerine to the polymerizing system. Since vinyl monomers forming Unit B function as a themselves, this property may be appropriately taken advantage of. The water-soluble vinyl copolymers constituting of Units A-D, to be used as a cement dispersant according to this invention, contain Unit A by 40-80 molar % or preferably by 55-72 molar %, Unit B by 0.5-20 molar % or preferably 3-18 molar %, Unit C by 0.2-18 molar % or preferably 3-15 molar %, and Unit D by 2-40 molar % or preferably 3-30 molar % (such that the total is 100 molar %). Those constituting of Units A, B, C, E and F contain Unit A by 40-80 molar % or preferably 55-72 molar %, Unit B by 0.5-20 molar % or preferably 3-18 molar %, Unit C by 0.2-18 molar % or preferably 3-15 molar %, Unit E by 2-15 molar % or preferably 3-12 molar %, and Unit F by 0.5-15 molar % or preferably 1-12 molar % (such that the total is 100 molar %). The water-soluble vinyl copolymers to be used as a cement dispersant according to this invention are further characterized in that their weight average molecular weight be 15000-150000 or preferably 25000-70000 and that their ratio Mw/Mn be 2-7 or preferably 3-6.5. 5A This invention also relates to a method of producing concrete, said method comprising the step of mixing cement aggregates, a cement dispersant and water such that concrete with water-to-cement ratio of 20-45% is produced, said cement dispersant consisting of water-soluble vinyl copolymers comprising 40 to 80 molar % of Unit A having Formula (1), 0.5 to 20 molar % of Unit B having FormuJa (2), 0.2 to 18 molar % of the Unit C having Formula (3) and 2 to 40 molar % of the Unit D having Formula (4), total content of said Units A, B, C and D being 100 molar %, said water-soluble vinyl copolymers having weight-average molecular weight pullulan converted by GPC method 15000 to 150000 and ratio of weight average molecular weight to number-average molecular weight being 2 to 7, said Formulas (1) to (4) being given by : (Formula 1) (Formula 2) 5B (Formula 3) (Formula 4) where R\ R2 and R3 are each H or CH3, R4 is H or an alky! group with 1 to 3 carbon atoms, X is a group having Formula (5) or (6), said Formulas (5) and (6) being given by : -SO3M2 (Formula 5) _O-C6H4-SO3M3 (Formula 6) A is a residual group obtainable by removing all hydroxyl groups from polyether diol with repetition number of oxyalkylene units being 5 to 109, the oxyalkylene units consisting either only of oxyethylene units or of both oxyethylene and oxypropylene units, M1 is H, an alkali metal, an alkali earth metal, ammonium or an organic amine, and M2 and M3 are each an alkali metal, an alkali earth metal, ammonium or an organic amine. 6 For preparing cement compositions by using a cement dispersant of this invention, different kinds of agents may be used together, depending of the purpose. Examples of such agents include air entraining agents, antifoaming agents, waterproofing agents, hardening accelerators and antiseptics. They may be added with kneading water when the cement composition is prepared or after the cement composition has been mixed and kneaded. Cement dispersants of this invention can be used for cement compositions such as mortars and concrete prepared by using a binder composed of cement or a mixture of cement and a microscopic powder admixture. Examples of cement which can be used include many kinds of Portland cement such as ordinary portland cement, high early strength portland cement and moderate heat portland cement, blast furnace cement, fly ash cement, silica fume cement as well as many other kinds of blended cement. Examples of microscopic powder admixture include silica fume, blast-furnace slag and fly ash. Cement dispersants of this invention are normally mixed at a ratio of 0.05-2.0 weight parts, or preferably 0.1-1.5 weight parts, as converted to solid component per 100 weight parts of the binder comprised of cement or a mixture of cement and a microscopic powder admixture. As explained above, water-soluble vinyl copolymers to be used as a cement dispersant according to this invention are characterized not only as constituting of Units A-D, or preferably Units A, B, C, E and F, at a specified ratio, but also as having weight average molecular weight and Mw/Mn within specified ranges. Those constituting of Units A, B, C, E and F are particularly characterized as containing in the molecule both a relatively long polyoxyethylene graft chain and a relatively short polyoxyethylene graft chain. Cement dispersants of this invention with such particular characteristic are effective not only when used with ordinary cement compositions with the water/cement ratio in excess of 45% but also with cement compositions with the water/cement ratio 20-45% such as concrete. They can provide high fluidity even to high-strength concrete with the water/cement ratio limited to 20-45%, reduce the slump loss, limit the setting time delay and realize a sufficient early strength. The invention is described next by way of the following thirteen embodiments. Embodiment (1) Cement dispersant using water-soluble vinyl copolyjngr with sodium methacrylate as Unit A by 63 molar %, sodium methallyl sulfonate as Unit B by 15 molar %, methyl acrylate as Unit C by 8 molar % and methoxy poly(p=45)ethylene glycol monomethacrylate (the repetition number of oxyethylene units being indicated hereinafter by "p") as Unit D by 14 molar % (such that the total is 100 molar %), of which the weight average molecular weight is 42500 and Mw/Mn = 4.6. 7 Embodiment (2) Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 67 molar %, sodium methallyl sulfonate as Unit B by 15 molar %, methyl acrylate as Unit C by 11 molar % and methoxy poly(p=68)ethylene glycol monomethacrylate as Unit D by 7 molar % (the total being 100 molar %), of which the weight average molecular weight is 46000 and Mw/Mn = 4.8. Embodiment (3) Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 72 molar %, sodium methallyl sulfonate as Unit B by 9 molar %, methyl acrylate as Unit C by 14 molar % and methoxy poly(p=90)ethylene glycol monomethacrylate as Unit D by 5 molar % (the total being 100 molar %), of which the weight average molecular weight is 59000 and Mw/Mn = 5.7. Embodiment (4) Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 60 molar %, sodium methallyi sulfonate as Unit B by 5 molar %, methyl acrylate as Unit C by 10 molar % and methoxy poly(p=45)ethylene glycol monomethacrylate as Unit D by 25 molar % (the total being 100 molar %), of which the weight average molecular weight 40700 is and Mw/Mn = 4.3. Embodiment (5) Cement dispersant using water-soluble vinyl copolymer with sodium acrylate as Unit A by 55 molar %, sodium p-methallyl oxybenzene sulfonate as Unit B by 15 molar %, methyl acrylate as Unit C by 3 molar % and methoxy poJy(p=:45)ethylene glycol monomethacrylate as Unit D by 27 molar % (the total being 100 molar %), of which the weight average molecular weight is 51500 and Mw/Mn = 3.2. Embodiment (6) Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 62 molar %, sodium p-methallyl oxybenzene sulfonate as Unit B by 12 molar %, methyl acrylate as Unit C by 6 molar % and methoxy poly(p=45)ethylene glycol monomethacrylate as Unit D by 20 molar % (the total being 100 molar %), of which the weight average molecular weight is 38700 and Mw/Mn = 3.5. 8 Embodiment (1) Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 70 molar %, sodium methallyl sulfonate as Unit B by 14 molar %, methyl acrylate as Unit C by 10 molar % and polyethylene glycol (p=90) monomethacrylate as Unit D by 6 molar % (the total being 100 molar %), of which the weight average molecular weight is 54800 and Mw/Mn = 5.1. Embodiment (8) Cement dispersant using water-soluble vinyl copolymer with sodium methacryiate as Unit A by 62 molar %, sodium methallyl sulfonate as Unit B by 12 molar %, methyl acrylate as Unit C by 12 molar %, methoxypolyethoxyethyt (n in Formula (7) = 68) methacrylate as Unit E by 8 molar % and methoxypolyethoxyethyl (m in Formula (8) = 9) methacrylate as Unit F by 6 molar % (the total being 100 molar %), of which the weight average molecular weight is 66600 and Mw/Mn = 4.5. Embodiment (9) Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 57 molar %, sodium methallyl sulfonate as Unit B by 15 molar %, methyl acrylate as Unit C by 14 molar %, methoxypolyethoxyethyl (n in Formula (7) = 68) methacrylate as Unit E by 10 molar % and methoxypolyethoxyethyl (m in Formula (8) = 23) methacrylate as Unit F by 2 molar % (the total being 100 molar %), of which the weight average molecular weight is 38500 andMw/Mn = 3.5. Embodiment (10) Cement dispersant using water-solubfe vinyl copolymer with sodium methacrylate as Unit A by 72 molar %, sodium methallyl sulfonate as Unit B by 8 molar %, methyl acrylate as Unit C by 5 molar %, methoxypolyethoxyethyl (n in Formula (7) = 95) methacrylate as Unit E by 4 molar % and methoxypolyethoxyethyl (m in Formula (8) = 9) methacrylate as Unit F by 11 9 molar % (the total being 100 molar %), of which the weight average molecular weight is 62900 and Mw/Mn = 3.4. Embodiment (ll) Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 65 molar %, sodium methallyl sulfonate as Unit B by 5 molar %, methyl acrylate as Unit C by 10 molar %, methoxypolyethoxyethyl (n in Formula (7) = 45) methacrylate as Unit E by 12 molar % and methoxypolyethoxyethyl (m in Formula (8) = 23) methacrylate as Unit F by 8 molar % (the total being 100 molar %), of which the weight average molecular weight is 114700 andMw/Mn = 3.1. Embodiment (12) Cement dispersant using water-soluble vinyl copolymer with sodium acrylate as Unit A by 70 molar %, sodium p-methallyl oxybenzene sulfonate as Unit B by 10 molar %, methyl acrylate as Unit C by 6 molar %, isopropoxypolyethoxyethyl (n in Formula (7) = 55) acrylate as Unit E by 11 molar % and methoxypolyethoxyethyl (m in Formula (8) = 9) methacrylate as Unit F by 3 molar % (the total being 100 molar %), of which the weight average molecular weight is 89700 and Mw/Mn = 3.9. Embodiment (13) Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 58 molar %, sodium p-methallyl oxybenzene sulfonate as Unit B by 18 molar %, methyl acrylate as Unit C by 8 molar %} methoxypolyethoxyethyl (n in Formula (7) = 68) methacrylate as Unit E by 10 molar % and methoxypolyethoxyethyl (m in Formula (8) = 23) methacrylate as Unit F by 6 molar % (the total being 100 molar %), of which the weight average molecular weight is 51000 and Mw/Mn = 6.0. Examples The invention will be described next by way of examples but these examples are not intended to limit the scope of the invention. In what follows, "parts" shall mean "weight parts" and "%" shall mean "weight % excluding the weight of air", unless otherwise noted. Part 1 (Synthesis of water-soluble vinyl copolymers) Synthesis of Test Example 1 Methacrylic acid 103 parts (1.20 moles), sodium methallyl sulfonate 47 parts (0.29 moles), methyl acrylate 13 parts (0.15 moles), methoxypoly(p=45)ethylene glycol monomethacrylate 559 10 parts (0.27 moles) and water 1500 parts were placed inside a reactor vessel, and after a 30% water solution of sodium hydroxide 90 parts was added to adjust the pH and to obtain a uniform solution, the atmosphere was replaced with nitrogen gas. The pH was of the reacting system was 5.8. The temperature of the reacting system was maintained at 60 °C by means of a temperature bath and a polymerization process was started by adding a 20% water solution of sodium persulfate 30 parts by titration over 3 hours. The polymerization process was continued for 2 hours more to conclude the polymerization. Thereafter, a 30% water solution of sodium hydroxide 10 parts was added for complete neutralization to obtain a reaction product. After a portion of the product thus obtained was condensed inside an evaporator, it was precipitated and refined inside a mixed acetone/isopropanol solvent and dried to obtain water-soluble vinyl copolymer (Test Example 1). This water-soluble vinyl copolymer (Test Example 1) was analyzed by NMR, elemental analysis, titration method and GPC and was found to be a water-soluble vinyl copolymer having sodium methacrylate as Unit A by 63 molar %, sodium methallyl sulfonate as Unit B by 15 molar %, methyl acrylate as Unit C by 8 molar % and methoxypoly(p=45)ethylene glycol monomethacrylate as Unit D by 14 molar % (the total being 100 weight %), of which the weight average molecular weight was 42500 and Mw/Mn = 4.6. Synthesis of Test Example 2 Methacrylic acid 153 parts (1.57 moles), sodium methallyl sulfonate 63 parts (0.40 moles), methyl acrylate 23 parts (0.27 moles), methoxypoly(p=68)ethylene glycol monomethacryiate 560 parts (0.18 moles) and water 1600 parts were placed inside a reactor vessel, and after a 30% water solution of sodium hydroxide 147 parts was added to adjust the pH and to obtain a uniform solution, the atmosphere was replaced with nitrogen gas. The pH was of the reacting system was 5.5. The temperature of the reacting system was maintained at 60°C by means of a temperature bath and a polymerization process was started by adding a 20% water solution of sodium persulfate 40 parts by titration over 3 hours. The polymerization process was continued for 3 hours more to conclude the polymerization. Thereafter, a 30% water solution of sodium hydroxide 63 parts was added for complete neutralization to obtain a reaction product. After a portion of the product thus obtained was condensed inside an evaporator, it was refined and dried by using a mixed solvent to obtain water-soluble vinyl copolymer (Test Example 2). This water-soluble vinyl copolymer (Test Example 2) was analyzed by NMR, elemental analysis, titration method and GPC and was found to be a water-soluble vinyl copolymer having sodium methacrylate as Unit A by 67 molar %, sodium methallyl sulfonate as Unit B by 15 molar %, methyl acrylate as Unit C by 11 molar % and methoxypoly(p=68)ethylene glycol monomethacrylate as Unit D by 7 molar % (the total being 100 weight %), of which the weight average molecular weight was 46000 and Mw/Mn = 4.8. 11 Synthesis of Test Examples 3-13 Water-soluble vinyl copolymers (Test Examples 3-13) were similarly obtained as explained above for the production of Test Examples 1 and 2. Their compositions are shown in Table 1. Synthesis of Comparison Example 1 Methacrylic acid 103 parts (1.20 moles), sodium methallyl sulfonate 14 parts (0.086 moles), methoxypoly(p=45)ethylene glycol monomethacrylate 891 parts (0.428 moles) and water 2100 parts were placed inside a reactor vessel, and after a 30% water solution of sodium hydroxide 160 parts was added to adjust the pH and to obtain a uniform solution, the atmosphere was replaced with nitrogen gas. The pH was of the reacting system was 9.2. The temperature of the reacting system was maintained at 60°C by means of a temperature bath and a polymerization process was started by adding a 20% water solution of sodium persulfate 50 parts by titration over 3 hours to obtain a reaction product. After a portion of the product thus obtained was condensed inside an evaporator, it was refined and dried by using a mixed solvent to obtain water-soluble vinyl copofymer (Comparison Example 1). This water-soluble vinyl copolymer (Comparison Example 1) was analyzed similarly as explained above and was found to be a water-solubie vinyl copolymer having sodium methacrylate as Unit A by 70 molar %, sodium methallyl sulfonate as Unit B by 5 molar %, and methoxypoly(p-45)ethylene glycol monomethacrylate as Unit D by 25 molar % (the total being 100 weight %), of which the weight average molecular weight was 62500 and Mw/Mn = 8.3. Synthesis of Comparison Examples 2-15 Water-soluble vinyl copolymers (Comparison Examples 2-15) were similarly obtained as explained above for the production of Comparison Example 1. Their compositions are shown in Table 2. 12 Table 1 Kinds and molar % of constituent Units WAMW Mw/Mn Unit A UnitB Unii tC Unit D Unit E Unit F Test Example: 1 A-l 63 B-l 15 C-l 8 D-l 14 - - 42500 4.6 2 A-l 67 B-l 15 C-l 11 D-2 7 - - 46000 4.8 3 A-l 72 B-l 9 C-l 14 D-3 5 - - 59000 5.7 4 A-l 60 B-l 5 C-l 10 D-l 25 - - 40700 4.3 5 A-2 55 B-2 15 C-l 3 D-l 27 - - 51500 3.2 6 A-l 62 B-2 12 C-l 6 D-l 20 - - 38700 3.5 7 A-l 70 B-l 14 C-l 10 D-4 6 - - 54800 5.1 8 A-l 62 B-l 12 C-l 12 E-l 8 F-l 6 66600 4.5 9 A-l 57 B-l 15 C-l 14 E-l 10 F-2 2 38500 3.5 10 A-l 72 B-l 8 C-l 5 E-2 4 F-l 11 62900 3:4 11 A-l 65 B-l 5 C-l 10 E-3 12 F-2 8 114700 3.1 12 A-2 70 B-2 10 C-l 6 E-4 11 F-l 3 89700 3.9 13 A-3 58 B-2 18 C-l 8 E-l 10 F-2 6 51000 6.0 In Table 1 and thereafter; WAMW: Weight average molecular weight 13 Table 2 Kinds and molar % of constituent Units WAMW Mw/Mn Unit A Unit B Unit C Unit D Unit E Unit F Others In Tables 1 and 2: A-l: Unit of sodium methacrylate A-2: Unit of sodium acrylate A-3: Unit of methacrylic acid B-l: Unit of sodium methallyl sulfonate B-2: Unit of sodium p-methallyl oxybenzene sulfonate C-l: Unit of methyl acrylate D-1: Unit of methoxy poly(p=45)ethylene glycol methacrylate D-2: Unit of methoxy poly(p=68)ethylene glycol methacrylate D-3: Unit of methoxy poly(p=90)ethylene glycol methacrylate D-4: Unit of polyethylene glycol (p=90) monomethacrylate E-l(D-2): Unit of methoxypolyethoxyethyl (n in Formula (7) = 68) methacrylate E-2: Unit of methoxypolyethoxyethyl (n in Formula (7) = 95) methacrylate E-3(D-1): Unit of methoxypolyethoxyethyl (n in Formula (7) = 45) methacrylate E-4: Unit of isopropoxy polyethoxyethyl (n in Formula (7) = 55) acrylate F-1: Unit of methoxypolyethoxyethyl (m in Formula (8) = 9) methacrylate F-2: Unit of methoxypolyethoxyethyl (m in Formula (8) = 23) methacrylate X-l: Unit of methoxypoly(p=150)ethylene glycol methacrylate X-2: Unit of methoxypoly(p=3)ethylene glycol methacrylate X-3: Unit of sodium styrene sulfonate X-4; Unit of 2-hydroxyethyl methacrylate 14 Part 2 (Preparation and Evaluation of Concrete) Preparation of Concrete Each of the test examples of concrete was prepared by placing ordinary portland cement (specific weight=3.16, Braine vaIue=33OO), fine aggregates (sand from Ooi River with specific weight=2.63) and coarse aggregates (crushed stone from Okazaki with specific weight=2.66) sequentially into a 50-liter pan-type forced kneading mixer under the conditions shown in Table 3 and kneaded for 15 seconds. Next, the cement dispersants prepared in Part 1 were added together with kneading water at a rate of 0.1 -1.5 weight % with respect to the cement converted to solid components such that the target slump value would be within the range of 21±lcm and the mixture was kneaded for 2 minutes. An agent for controlling the amount of air was kneaded in with water in each case such that the target air content would become 4.0-5.0%. Table 3 Condition of Water/ Cement Sand-Coarse Aggregate Used materials fke/m3 ) Preparation Ratio (%) Ratio (%) Water Cement Fine aggregate Coarse aggregate 1 2 33 50 44 49 165 165 500 330 742 867 944 960 Evaluation of Concrete For each of test and comparison examples, slump value (SV), air quantity (AQ), setting time and compression strength were measured according respectively to J1S-A1101, JIS-Al 128, JIS-A6204 and JIS-A1108 immediately after the kneading (t=0), 60 minutes later (t=60) and 90 minutes later (t=90). The results are shown in Tables 4-7. In these Tables, the numbers in parentheses following the test and comparison example numbers indicate the condition of preparation defined in Table 3. Slump ratio is defined as the percentage ratio of the slump value after 90 minutes to the slump value immediately after the kneading. These tables clearly show that cement dispersants according to this invention can provide a high level of fluidity while limiting the slump loss, as well as a high early strength at the initial period of hardening. 15 Table 4 Test Cemen t t=0 t=60 t=90 Slump No. dispersant Ratio fft/ Kind Amount sv AQ SV AQ SV AQ (%) (Part)(l) (cm) (%) (cm) (%) (cm) (%) Test Examoles 1 HI) 0.22 21.5 4.5 20.4 4.4 19.6 4.4 91.1 2 2(1) 0.20 21.7 4.8 20.7 4.6 19.8 4.5 91.2 3 3(1) 0.22 21.8 4.6 20.2 4.5 19.4 4.2 89.0 4 4(1) 0.27 21.5 4.5 21.0 4,3 19.9 4.0 92.5 5 5(1) 0.34 21.3 4.7 19.9 4.3 18.7 4,1 87.8 6 6(1) 0.28 21.5 4.4 20.6 4.2 19.5 4.0 90.7 7 7(1) 0.21 21.2 4.6 19.6 4.4 18.4 4.2 86.8 8 1(2) 0.19 21.4 4.6 20.3 4.5 19.9 4.3 89.2 9 2(2) 0.18 21.5 4.7 20.7 4.5 19.4 4.4 90.2 10 3(2) 0.20 21.7 4.6 20.1 4.3 18.8 4.3 86.6 11 4(2) 0.24 21.4 4.6 20.3 ' 4.5 19.5 4.5 91.1 12 5(2) 0.30 21.8 4.7 20.1 4.5 18.7 4.3 85.8 13 6(2) 0.24 21.4 4.6 20.7 4.5 19.3 4.3 90.2 14 7(2) 0.19 21.6 4.4 20.0 4.4 18.6 4.2 86.1 15 8(1) 0.18 21.7 4.6 20.5 4.4 20.2 4.3 93.1 16 9(1) 0.17 21.5 4.5 21.0 4.5 19.8 4.3 92.1 17 10(1) 0.21 21.4 4.6 20.9 4.4 20.4 4.4 95.3 18 11(1) 0.26 21.6 4.4 20.8 4.4 20.1 4.2 93.1 19 12(1) 0.24 21.3 4.7 20.4 4.3 19.7 4.1 92.5 20 13(1) 0.16 21.6 4.5 20.5 4.2 19.9 4.0 91.7 21 8(2) 0.15 21.5 4.4 20.7 4.2 19.4 4.2 90.2 22 9(2) 0.14 21.8 4.6 21.0 4.3 19.9 4.2 91.3 23 10(2) 0.22 21.6 4.5 21.1 4.5 20.2 4.3 92.5 24 11(2) 0.25 21.3 4.7 20.4 4.6 19.5 4.4 91.5 25 12(2) 0.23 21.7 4.8 20.3 4.5 19.7 4.3 90.8 26 13(2) 0.19 21.5 4.5 20.6 4.4 19.4 4.2 90.2 1: The amount of cement dispersant is shown as converted to solid components with respect to 100 parts of cement. (1), (2): Condition No. for preparation of concrete 16 Table 5 Test Cemen t t=0 t=60 t=90 Slump No. dispersant Ratio Kind Amount SV AQ SV AQ SV AQ (%) (Part)(l) (cm) (%) (cm) (%) (cm) (%) Comparison Examples 27 1(1) 0.280 21.5 4.9 17.1 4.4 13.4 4.4 64.5 28 2(1) 0.30 21.7 4.6 16.0 4.5 12.1 4.2 57.9 29 3(1) 0.55 21.2 4.5 15.0 4.3 11.8 4.0 72.4 30 4(1) 0.45 21.3 4.4 17.7 4.1 15.2 4.1 76.7 31 5(1) 0.29 21.6 4.6 17.3 4.4 14.6 4.2 70.8 32 6(1) 0.60 21.2 4.8 16.4 4.6 12.9 4.2 60.7 33 7(1) 0.35 21.4 4.8 15.0 4.5 10.8 4.1 50.5 34 8(1) 0.43 21.6 4.6 13.8 4.6 9.2 4.4 47.9 35 9(1) 0.31 21.3 4.7 15.5 4.6 12.5 4.4 62.0 36 10(1) 0.95 21.2 4.8 14.5 4.6 10.7 4.3 45.0 37 11(1) 0.49 21.7 4.8 15.2 4.6 11.8 4.5 54.3 38 12(1) 0.47 21.4 4.6 15.7 4.4 12.0 4.1 56.1 39 1(2) 0.27 21.6 4.7 15.7 4.4 13.3 4.2 61.6 40 2(2) 0.29 21.3 4.6 15.0 4.3 o 10.1 4.1 47.4 41 3(2) 0.48 21.5 4.9 17.0 4.6 15.0 4.5 69.8 42 4(2) 0.42 21.8 4.5 17.2 4.4 15.6 4.3 71.6 43 5(2) 0.27 21.4 4.6 16.9 4.5 13.9 4.5 65.0 44 6(2) 0.58 21.7 4.5 13.5 4.4 11.2 4.2 51.6 45 7(2) 0.32 21.5 4.7 12.8 4.5 10.4 4.4 48.4 46 8(2) 0.40 21.4 4.8 12.0 4.7 9.2 4.2 43.0 47 9(2) 0.30 21.6 4.6 16.2 4.4 13.0 4.4 60.2 48 10(2) 0.90 21.7 4.8 12.1 4.5 9.1 4.4 41.9 49 11(2) 0.45 21.9 4.7 12.8 4.5 12.2 4.3 41.4 50 12(2) 0.42 21.3 4.9 13.0 4.4 11.4 4.1 53.5 51 13(1) 0.47 21.8 4.8 15.2 4.4 11.0 4.1 50.5 52 14(1) 0.36 21.5 4.6 14.4 4.3 10.3 4.3 47.9 53 15(1) 0.58 21.3 4.7 16.0 4.4 13.2 4.4 62.0 54 13(2) 0.53 21.6 4.6 12.8 4.5 10.4 4.3 48.1 55 14(2) 0.34 21.2 4.8 12.3 4.6 9.7 4.4 45.8 56 15(2) 0.50 21.5 4.5 16.7 4.5 13.2 4.3 61.4 57 o2(1) 0.76 21.7 4.6 11.2 4.2 9.0 4.0 41.4 1: The amount of cement dispersant is shown as converted to solid components with respect to 100 parts of cement. 2: Salt of high condensates of naphthalene sulfonic acid formaldehyde (Polefine 510-AN, tradename of Takemoto Yushi Kabushiki Kaisha) (1), (2): Condition No. for preparation of concrete 17 Table 6 Test Setting \ Time Compressive Strength (N/mm2) No. Start End Time Time Time Time Time (min) (min) (8h) (12h) (18h) (24h) (72h) 1 335 415 1.7 9.7 22.2 36.5 53.7 2 320 400 2.0 10.1 22.5 38.8 54.0 3 300 370 2.5 12.0 24.0 43.0 55.6 4 340 435 1.4 9.0 21.3 36.0 53.5 5 355 450 1.1 8.8 21.0 35.7 53.0 6 330 410 1.9 9.8 22.0 39.0 54.3 7 305 365 2.6 12.5 24.5 44.0 55.8 8 340 420 0.9 3.5 6.7 16.6 26.8 9 320 405 1.0 3.7 6.9 16.7 27.1 10 315 395 1.3 3.9 7.0 16.9 27.3 11 355 455 0.7 3.3 6.5 16.2 26.4 12 360 465 0.7 3.2 6.3 16.0 26.2 13 330 425 0.9 3.5 6.7 16.8 27.0 14 310 390 1.3 4.0 7.0 17.0 27.4 15 310 385 2.0 10.2 ¦ 22.5 38.6 53.8 16 300 375 2.4 12.0 24.0 43.5 55.7 17 330 405 1.7 9.6 22.0 36.2 54.0 18 335 420 1.5 9.3 21.7 35.7 53.0 19 330 410 1.7 9.5 22.1 36.0 53.1 20 305 390 2.2 11.8 24.0 43.6 55.6 21 320 410 1.0 3.7 6.8 16.6 26.9 22 310 395 1.2 3.9 7.0 16.8 27.2 23 355 450 0.8 3.4 6.5 16.4 26.5 24 360 460 0.7 3.4 6.6 16.5 26.5 25 350 445 0.8 3.6 6.5 16.7 26.6 26 335 420 0.9 3.5 6.6 16.6 26.7 18 Table 7 Test Setting , Time Compressive Strength (N/mm2) No. Start End Time Time Time Time Time (min) (min) (8h) (12h) (18h) (24h) (72h) 27 380 490 0.3 1.2 9.6 14.8 45.7 28 410 530 0.1 0.7 9.0 13.5 43.7 29 470 590 3 0.1 2.9 6.6 42.5 30 430 550 3 0,2 4.2 7.7 43.0 31 380 485 0.4 1.7 11.1 17.0 47.7 32 500 620 3 3 1.8 6.4 42.3 33 425 540 3 0.5 4.3 8.0 44.5 34 450 580 3 0.2 2.9 7.0 43.9 35 480 605 3 3 2.5 6.5 42.8 36 650 780 3 ?3 3 1.5 41.0 37 440 575 3 3 0.4 7.0 43.8 38 495 590 3 3 0.2 3.1 43.0 39 405 540 3 0.2 3.1 8.5 22.0 40 420 560 ?3 3 1.8 7.5 21.6 41 510 645 3 3 3 2.7 19.7 42 450 590 3 3 3 2.0 20.2 43 400 535 3 0.3 3.5 10.0 23.4 44 535 690 3 3 3 0.4 18.5 45 445 585 3 3 3 3.6 21.2 46 480 620 3 3 3 3.0 20.7 47 460 - 600 3 3 0.2 1.9 20.6 48 620 785 3 3 3 3 15.7 49 490 635 3 ?3 3 0.8 19.5 50 540 680 3 3 3 3 17.6 51 530 675 3 3 0.9 3.6 39.5 52 455 590 3 0.2 2.7 6.3 41.5 53 550 695 3 3 0.4 2.5 35.5 54 540 690 3 3 3 0.3 18.5 55 465 600 . 3 3 3 1.9 19.0 56 530 670 3 3 3 0.5 19.8 57 360 445 0.7 3.0 16.2 28.9 51.7 3: No measurement could be taken because there was no hardening. 19 WE CLAIM : 1. A method for the production of a cement dispersant comprising water-soluble vinyl copolymers, in which the water-soluble vinyl copolymers is obtained by radical copolymerization of a mixture of a vinyl monomer to form Unit A having Formula (1), a vinyl monomer to form Unit B having Formula (2), a vinyl monomer to form Unit C having Formula (3) and a vinyl monomer to form Unit D having Formula (4) in the presence of a radical initiator in an aqueous solution, the obtained water-soluble vinyl copolymers having 40 to 80 molar % of the Unit A, 0.5 to 20 molar % of the Unit B, 0.2 to 18 molar % of the Unit C and 2 to 40 molar % of the Unit D, the total content of the Units A, B, C and D being 100 molar %, pullulan-converted weight-average molecular weight measured by Gel Permeation Chromatography (GPC) Method of the water-soluble vinyl copolymers being 15000 to 150000 and the ratio of the weight-average molecular weight to number-average molecular weight being 2 to 7, said Formulas (1) to (4) being given by: (Formula 1) (Formula 2) 20 R2 I _ ( CH^-C ) - I COOCHa R3 I - ( CH^-C ) - I COOW\-OR* (Formula 3) (Formula 4) where R\ R2 and R3 are each H or CH3, R4 is H or an alkyl group with 1 to 3 carbon atoms, X is a group having Formula (5) or (6), said Formulas (5) and (6) being given by : -SCW (Formulas) -O-CsH4-S03M3 (Formula 6) A is a residual group obtainable by removing all hydroxyl groups from polyether diol with repetition number of oxyalkylene units being 5 to 109, the oxyalkylene units consisting either only of oxyethylene units or of both oxyethylene and oxypropylene units, M1 is H, an alkali metal, an alkali earth metal, ammonium or an organic amine, and M2 and M3 are each an alkali metal, an alkali earth metal, ammonium or an organic amine. 21 2. The method as claimed in claim 1, wherein the vinyl monomer to form the Unit D consists of a vinyl monomer to form Unit E having Formula (7) and a vinyl monomer to form Unit F having Formula (8) and the obtained water-soluble vinyl copolymers contain 2 to 15 molar % of said Unit E and 0.5 to 15 molar % of said Unit F, said formulas (7) and (8) being given by - (Formula 7) (Formula 8) where R5 is H or CH3, R6 is an alkyl group with 1 to 3 carbon atoms, n is an integer of 40 to 109 and m is an integer of 5 to 25. 3. The method as claimed in claim 2, wherein the obtained water-soluble vinyl copolymers contain 55 to 72 molar % of said Unit A , 3 to 18 molar % of said Unit B, 3 to 15 molar % of said Unite, 3 to 12 molar % of said Unit E and 1 to 12 molar % of said Unit F, with the total being 100 molar %. 22 4. The method as claimed in claim 1, wherein pullulan-converted weight- average molecular weight measured by Gel Permeation Chromatography (GPC) Method of the obtained water-soluble vinyl copolymers is 25000 to 70000 and the ratio of the weight-average molecular weight to number-average molecular weight is 3 to 6.5 5. The method as claimed in claim 2, wherein pullulan-converted weight- average molecular weight measured by Gel Permeation Chromatography (GPC) method of the obtained water-soluble vinyl copolymers is 25000 to 70000 and the ratio of the weight-average molecular weight to number-average molecular weight is 3 to 6.5. 6. The method as claimed in claim 3, wherein pullulan-converted weight- average molecular weight measured by Gel Permeation Chromatography (GPC) method of the obtained water-soluble vinyl copolymers is 25000 to 70000 and the ratio of the weight-average molecular weight to number-average molecular weight is 3 to 6.5. 7. A method of producing concrete, said method comprising the step of mixing cement aggregates, a cement dispersant and water such that concrete with water-to- cement ratio of 20 to 45% is produced, said cement dispersant consisting of water- soluble vinyl copolymers comprising 40 to 80 molar % of Unit A having Formula (1), 0.5 to 20 molar % of Unit B having Formula (2), 0.2 to 18 molar % of Unit C having Formula (3) and 2 to 40 molar % of Unit D having Formula (4), total content of said Units A, B, C and D being 100 molar %, said water-soluble vinyl copolymers having weight-average molecular weight pullulan converted by GPC method 15000 to 150000 and ratio of weight average molecular weight to number-average molecular weight being 2 to 7, said Formulas (1) to (4) being given by : 23 R1 (Formula 1) (Formula 2) (Formula 3) (Formula 4) where R\ R2 and R3 are each H or CH3, R4 is H or an alky! group with 1 to 3 carbon atoms, X is a group having Formula (5) or (6), said Formulas (5) and (6) being given by -SO3M2 (Formula 5) -O~CSH4-SO3M3 (Formula 6) 24 A is a residual group obtainable by removing all hydroxyl groups from polyether dioj with repetition number of oxyalkylene units being 5 to 109, the oxyalkylene units consisting either only of oxyethylene units or of both oxyethylene and oxypropylene units, M1 is H, an alkali metal, an alkali earth metal, ammonium or an organic amine, and M2 and M3 are each an alkali metal, an alkali earth metal, ammonium or an organic amine. 8. The method as claimed in claim 7, wherein said Unit D consists of Unit E having Formula (7) and Unit F having Formula (8), and said water-soluble vinyl copolymers containing 2 to 15 molar % of said Unit E and said 0.5 to 15 molar % of Unit F, said Formulas (7) and (8) being given by - (Formula 7) (Formula 8) where Rs is H or CH3, Rs is an alkyl group with 1 to 3 carbon atoms, n is an integer of 40 to 109 and m is an integer of 5 to 25. 25 9. The method as claimed in claim 8, wherein the obtained water-soluble vinyl copolymers contain 55 to 72 molar % of said Unit A, 3 to 18 molar % of said Unit B, 3 to 15 molar % of said Unit C, 3 to 12 molar of said Unit E and 1 to 12 molar % of said Unit F. 10. The method as claimed in claim 7, wherein said water-soluble vinyl copolymers have weight-average molecular weight pullulan converted by Gel Permeation Chromatography (GPC) method 25000 to 70000 and the ratio of weight-average molecular weight to number-average molecular weight 3 to 6.5. 11. The method as claimed in claim 8, wherein said water-soluble vinyl copolymers have weight-average molecular weight pullulan converted by Gel Permeation Chromatography (GPC) method 25000 to 70000 and the ratio of weight-average molecular weight to number-average molecular weight 3 to 6.5. 12. The method as claimed in claim 9, wherein said water-soluble vinyl copolymers have weight-average molecular weight pullulan converted by Gel Permeation Chromatography (GPC) method 25000 to 70000 and the ratio of weight-average molecular weight to number-average molecular weight 3 to 6.5. -26- 13. A method for the production of a cement dispersant, substantially as herein described, particularly with reference to and as illustrated in the foregoing examples. 14. A method of producing concrete, substantially as herein described, particularly with reference to and as illustrated in the foregoing examples. A method for the production of a cement dispersant comprising water-soluble vinyl copolymers, in which the water-soluble vinyl copolymers is obtained by radical copolymerization of a mixture of a vinyl monomer to form Unit A, a vinyl monomer to form Unit B, a vinyl monomer to form Unit C, and a vinyl monomer to form Unit D in the presence of a radical initiator in an aqueous solution, the obtained water-soluble vinyl copolymers having 40 to 80 molar % of the Unit A, 0.5 to 20 molar % of the Unit B, 0.2 to 18 molar % of the Unit C and 2 to 40 molar % of the Unit D, the total content of the Units A, B, C and D being 100 molar %, pullulan-converted weight-average molecular weight measured by Gel Permeation Chromatography Method of the water-soluble vinyl copolymers being 15000 to 150000 and the ratio of the weight-average molecular weight to number-average molecular weight being 2 to 7. Unit A can be formed by sodium salt of acrylic acid. Unit B can be formed by sodium salt of methallyl sulfonic acid. Unit C can be formed by methyl acrylate. Unit D can be formed by methoxy polyethylene glycol methacrylate with oxyalkylene units including only oxyethylene units and their repetition number in the range of 26 to 95.

Full Text

1A Field of invention :
This invention relates to a method for the production of a cement dispersant and a method of producing concrete. At work sites where cement compositions are used, it is important to be able to provide high fluidity to cement compositions, to reduce the drop in the proyided fluidity with time ("the slump loss") and to obtain a sufficient early strength during the initial period of hardening such that the frames can be removed quickly and the work efficiency can be thereby improved. This invention relates to cement dispersants which can respond to such requirements, as well as methods of using such cement dispersants to produce concrete with improved quality. This invention also relates to concrete produced by using such a cement dispersant.
Examples of prior art cement dispersant for providing fluidity to cement compositions include salts of high condensates of naphthalene sulfonic acid formaldehyde and melamine sulfonic acid formaldehyde, as well as water-soluble vinyl copolymers. Cement compositions prepared by using salts of high condensates of naphthalene sulfonic acid formaldehyde or melamine sulfonic acid formaldehyde, however, have the problem of a high slump loss. Those prepared by using water-soluble vinyl copolymers of the conventionally proposed kind (such as disclosed in Japanese Patent Publications Tokko 58-38380, 59-18338 and 5-11057 and U.S. Patents 4 962 173, 5 087 648, 5 290 869 and 5 362 829 ) have smaller slump losses but there are problems wherein their setting times become longer and hence a sufficient early strength cannot be obtained during the early period of hardening. This problem is particularly significant with high-strength cement compositions with a limited water-to-cement ratio.

2
Summary of the Invention
The problem to be overcome by the present invention is that prior art cement dispersants could produce only cement compositions with a large slump loss or incapable of providing a sufficiently large early strength, this problem being particularly significant with high-strength cement compositions with a limited water-to-cement ratio.
The present invention was accomplished as a result of investigations by the present inventors and is based on their discovery that water-soluble vinyl copolymers constituting of specified kinds of constituent units (herein referred to simply as "units") at a specified ratio and having both the weight average molecular weight and the ratios between the weight average molecular weight and the number average molecular weight within a specified range are suitable as a cement dispersant.
Detailed Description of the Invention :
This invention provides a method for the production of a cement dispersant comprising of water-soluble vinyl copolymers, in which the water-soluble vinyl copolymers is obtained by radical copolymerization of a mixture of a vinyl monomer to form Unit A having Formula (1), a vinyl monomer to form Unit B having Formula (2), a vinyl monomer to form Unit C having Formula (3) and a vinyl monomer to form Unit D having Formula (4) in the presence of a radical initiator in an aqueous solution, the obtained water-soluble vinyl copolymers having 40 to 80 molar % of the Unit A, 0.5 to 20 molar % of the Unit B, 0.2 to 18 molar % of the Unit C and 2 to 40 molar % of the Unit D, the total content of the Units A, B, C and D being 100 molar %, pullulan-converted weight-average molecular weight measured by Gel Permeation Chromatography (GPC) Method of the water-soluble vinyl copolymers being 15000 to 150000 and the ratio of the

2A
weight-average molecular weight to number-average molecular weight being 2 to 7, said Formulas (1) to (4) being given by -

3
where
R\ R2 and R3 are each H or CH3,
R4 is H or an alkyl group with 1 to 3 carbon atoms,
X is a group having Formula (5) or (6), said Formulas being given by -
-SO3M2 (Formufa 5)
-O-C6H4-SO3M3 (Formula 6)
A is a residual group obtainable by removing a!! hydroxyl groups from
polyether dio! with repetition number of oxyalkylene units being 5 to 109, the oxyalkylene
units consisting either only of oxyethylene units or of both oxyethylene and oxypropylene
units,
M1 is H, an alkali metal, an alkali earth metal, ammonium or an organic
amine, and
M2 and M3 are each an alkali metal, an alkali earth metal, ammonium or
an organic amine.
Cement dispersants of this invention are a water-soluble vinyl copolymers
having four constituent units described above but those having as Unit D both Unit E
shown below by by Formula (7) and Unit F shown below by Formula (8) are
preferred:

{Formula 7)

3A

(Formula 8)

where R5 is H or CH3l R6 is an alkyl group with 1 to 3 carbon atoms, n is an integer of 40 to 109 and m is an integer of 5 to 25. In other words, preferred kinds of water-soluble vinyl copolymers according to this invention include not only Units A, B and C shown by Formulas (1), (2) and (3) but also a relatively long polyoxyethylene graft chain due to Unit E of Formula (7) and a relatively short chain polyoxyethylene graft chain.
These constituent Units A, B, C and D, or Units A, B, C, E and F in the case of an aforementioned preferred example, can all be formed by copolymerizing corresponding vinyl monomers. Examples of vinyl monomers which form Unit A shown by Formula (1) include (1) (meth)acrylicacid, and (2) alkali metal salts, alkali earth metal salts and organic amine salts of (meth)acrylic acid. Of these, alkali metal salts such as sodium and potassium salts of (meth)acryNc acid are prefered.
Examples of vinyl monomers which form Unit B shown by Formula (2) include (1) alkali metal salts, alkali earth metal salts and organic amine salts of methallyl sulfonic acid, and (2) alkali metal salts, alkali earth metal salts and organic amine salts of p-methallyl oxybenzene

4
sulfonic acid. Of these, alkali metal salts such as sodium and potassium salts of methallyl sulfonic acid are preferred.
Examples of vinyl monomers which form Unit C shown by Formula (3) include methyl acrylate and methyl methacrylate. Of these, methyl acrylate is preferred.
Examples of vinyl monomers which form Unit D shown by Formula (4) include (1) alkoxy polyoxyalkylene giycol (meth)acrylate with 1-3 carbon atoms and (2) polyoxyalkylene glycol mono(meth)acrylate1 both with repetition number of oxyalkylene units 5-109. Examples of (1) above include methoxy polyethylene glycol (meth)acrylate, methoxy polyethylene glycol polypropylene glycol (meth)acrylate, methoxy polypropylene glycol (meth)acrylate,, ethoxy polyethylene glycol (meth)acrylate, ethoxy polyethylene glycol polypropylene glycol (meth)acrylate, ethoxy polypropylene glycol (meth)acrylate, n-propoxy polyethylene glycol (meth)acrylate, n-propoxy polyethylene glycol polypropylene glycol (meth)acrylate, isopropoxy polyethylene glycol mono(meth)acrylate, and isopropoxy polyethylene glycol polypropylene glycol (meth)acrylate. Examples of (2) above include polyoxyalkylene glycol mono(meth)acrylates such as polyethylene glycol mono(meth)acrylate, polyethylene glycol polypropylene glycol mono(meth)acrylate, and polypropylene glycol mono(meth)acrylate. Of these, methoxy polyethylene glycol methacrylate and polyethylene glycol monomethacrylate with oxyalkylene units including only oxyethylene units and their repetition number in the range of 26-95 are preferred.
Examples of vinyl monomers which form Unit E shown by Formula (7) include alkoxy polyethoxyethyl (meth)acrylates with 1-3 carbon atoms and the repetition number of oxyethylene units in the range of 40-109 such as methoxy polyethoxyethyl (meth)acrylate, ethoxypolyethoxyethyl (meth)acrylate, n-propoxy polyethoxyethyl (meth)acrylate, and isopropoxy polyethoxyethyl (meth)acrylate. Of these, methoxy polyethoxyethyl methacrylates with the repetition number of oxyethylene units in the range of 55-100 are preferred.
Examples of vinyl monomers which form Unit F shown by Formula (8) include methoxy polyethoxyethyl methacrylates with the repetition number of oxyethylene units in the range of 5-25. Of these, methoxy polyethoxyethyl methacrylates with the repetition number of oxyethylene units in the range of 7-23 are preferred.
Water-soluble vinyl copolymers to be used as a cement dispersant according to this invention may be obtained by radical copofymerization of vinyl monomers forming Units A-D, or preferably Units A, B, C, E and F at a specified copolymerization ratio in the presence of a radical initiator. The radical copolymerization can be carried out by aqueous solution polymerization using water or a mixed solvent with water and a water-soluble organic solvent either continuously or by batches. For example, each of the vinyl monomers is initially dissolved in water to prepare an aqueous solution with pH 4.5-6.5 containing these vinyl monomers by 10-40 weight % as their

5
total. Next, a radical initiator is added to this aqueous solution within a nitrogen gas atmosphere to carry out a radical copolymerization reaction at 50-70°C for 5-8 hours and to thereby obtain water-soluble vinyl copolymer. Any radical initiator which generates radicals by decomposing at the reaction temperature of copolymerization may be used for the copolymerization reaction of either of the vinyl monomers, but the use of a water-soluble radical initiator is preferred. Examples of such water-soluble radical initiator include persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide, and 2,2-azobis (2-amidinopropane) dihydrochloride. They may be combined with a reducing agent such as a sulfite and L-ascorbic acid or amines to be used as a redox initiator.
As described above, water-soluble vinyl copolymers to be used as a cement dispersant according to this invention are characterized as comprising Units A-D, or preferably Units A, B, C, E and F at a specified ratio, but they are also required to have the weight average molecular weight (pullulan converted by GPC method) and the ratio of weight average molecular weight to number average molecular weight (hereinafter denoted as Mw/Mn) within specified ranges. Adjustment of such molecular weight distributions can be effected by a conventional method of appropriately controlling concentrations of the vinyl monomers in the system for radical copolymerization, the pH of the polymerizing system, its temperature and the addition of a chain transfer agent. In order to obtain a water-soluble vinyl copolymer with a desired molecular weight distribution, it is preferred to set the pH value of the polymerizing system at 4.0-6.5 and to add a chain transfer agent such as 2-mercapto ethanol, 2-mercapto propionic acid, 3-mercapto propionic acid, thioglycol acid and thioglycerine to the polymerizing system. Since vinyl monomers forming Unit B function as a themselves, this property may be appropriately taken advantage of.
The water-soluble vinyl copolymers constituting of Units A-D, to be used as a cement dispersant according to this invention, contain Unit A by 40-80 molar % or preferably by 55-72 molar %, Unit B by 0.5-20 molar % or preferably 3-18 molar %, Unit C by 0.2-18 molar % or preferably 3-15 molar %, and Unit D by 2-40 molar % or preferably 3-30 molar % (such that the total is 100 molar %). Those constituting of Units A, B, C, E and F contain Unit A by 40-80 molar % or preferably 55-72 molar %, Unit B by 0.5-20 molar % or preferably 3-18 molar %, Unit C by 0.2-18 molar % or preferably 3-15 molar %, Unit E by 2-15 molar % or preferably 3-12 molar %, and Unit F by 0.5-15 molar % or preferably 1-12 molar % (such that the total is 100 molar %).
The water-soluble vinyl copolymers to be used as a cement dispersant according to this invention are further characterized in that their weight average molecular weight be 15000-150000 or preferably 25000-70000 and that their ratio Mw/Mn be 2-7 or preferably 3-6.5.

5A

This invention also relates to a method of producing concrete, said method comprising the step of mixing cement aggregates, a cement dispersant and water such that concrete with water-to-cement ratio of 20-45% is produced, said cement dispersant consisting of water-soluble vinyl copolymers comprising 40 to 80 molar % of Unit A having Formula (1), 0.5 to 20 molar % of Unit B having FormuJa (2), 0.2 to 18 molar % of the Unit C having Formula (3) and 2 to 40 molar % of the Unit D having Formula (4), total content of said Units A, B, C and D being 100 molar %, said water-soluble vinyl copolymers having weight-average molecular weight pullulan converted by GPC method 15000 to 150000 and ratio of weight average molecular weight to number-average molecular weight being 2 to 7, said Formulas (1) to (4) being given by :
(Formula 1) (Formula 2)

5B

(Formula 3)
(Formula 4)
where
R\ R2 and R3 are each H or CH3,
R4 is H or an alky! group with 1 to 3 carbon atoms,
X is a group having Formula (5) or (6), said Formulas (5) and (6) being given by :
-SO3M2 (Formula 5)
_O-C6H4-SO3M3 (Formula 6)
A is a residual group obtainable by removing all hydroxyl groups from
polyether diol with repetition number of oxyalkylene units being 5 to 109, the oxyalkylene
units consisting either only of oxyethylene units or of both oxyethylene and oxypropylene
units,
M1 is H, an alkali metal, an alkali earth metal, ammonium or an organic
amine, and
M2 and M3 are each an alkali metal, an alkali earth metal, ammonium or an
organic amine.

6
For preparing cement compositions by using a cement dispersant of this invention, different kinds of agents may be used together, depending of the purpose. Examples of such agents include air entraining agents, antifoaming agents, waterproofing agents, hardening accelerators and antiseptics. They may be added with kneading water when the cement composition is prepared or after the cement composition has been mixed and kneaded.
Cement dispersants of this invention can be used for cement compositions such as mortars and concrete prepared by using a binder composed of cement or a mixture of cement and a microscopic powder admixture. Examples of cement which can be used include many kinds of Portland cement such as ordinary portland cement, high early strength portland cement and moderate heat portland cement, blast furnace cement, fly ash cement, silica fume cement as well as many other kinds of blended cement. Examples of microscopic powder admixture include silica fume, blast-furnace slag and fly ash. Cement dispersants of this invention are normally mixed at a ratio of 0.05-2.0 weight parts, or preferably 0.1-1.5 weight parts, as converted to solid component per 100 weight parts of the binder comprised of cement or a mixture of cement and a microscopic powder admixture.
As explained above, water-soluble vinyl copolymers to be used as a cement dispersant according to this invention are characterized not only as constituting of Units A-D, or preferably Units A, B, C, E and F, at a specified ratio, but also as having weight average molecular weight and Mw/Mn within specified ranges. Those constituting of Units A, B, C, E and F are particularly characterized as containing in the molecule both a relatively long polyoxyethylene graft chain and a relatively short polyoxyethylene graft chain. Cement dispersants of this invention with such particular characteristic are effective not only when used with ordinary cement compositions with the water/cement ratio in excess of 45% but also with cement compositions with the water/cement ratio 20-45% such as concrete. They can provide high fluidity even to high-strength concrete with the water/cement ratio limited to 20-45%, reduce the slump loss, limit the setting time delay and realize a sufficient early strength.
The invention is described next by way of the following thirteen embodiments.
Embodiment (1)
Cement dispersant using water-soluble vinyl copolyjngr with sodium methacrylate as Unit A by 63 molar %, sodium methallyl sulfonate as Unit B by 15 molar %, methyl acrylate as Unit C by 8 molar % and methoxy poly(p=45)ethylene glycol monomethacrylate (the repetition number of oxyethylene units being indicated hereinafter by "p") as Unit D by 14 molar % (such that the total is 100 molar %), of which the weight average molecular weight is 42500 and Mw/Mn = 4.6.

7
Embodiment (2)
Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 67 molar %, sodium methallyl sulfonate as Unit B by 15 molar %, methyl acrylate as Unit C by 11 molar % and methoxy poly(p=68)ethylene glycol monomethacrylate as Unit D by 7 molar % (the total being 100 molar %), of which the weight average molecular weight is 46000 and Mw/Mn = 4.8.
Embodiment (3)
Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 72 molar %, sodium methallyl sulfonate as Unit B by 9 molar %, methyl acrylate as Unit C by 14 molar % and methoxy poly(p=90)ethylene glycol monomethacrylate as Unit D by 5 molar % (the total being 100 molar %), of which the weight average molecular weight is 59000 and Mw/Mn = 5.7.
Embodiment (4)
Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 60 molar %, sodium methallyi sulfonate as Unit B by 5 molar %, methyl acrylate as Unit C by 10 molar % and methoxy poly(p=45)ethylene glycol monomethacrylate as Unit D by 25 molar % (the total being 100 molar %), of which the weight average molecular weight 40700 is and Mw/Mn = 4.3.
Embodiment (5)
Cement dispersant using water-soluble vinyl copolymer with sodium acrylate as Unit A by 55 molar %, sodium p-methallyl oxybenzene sulfonate as Unit B by 15 molar %, methyl acrylate as Unit C by 3 molar % and methoxy poJy(p=:45)ethylene glycol monomethacrylate as Unit D by 27 molar % (the total being 100 molar %), of which the weight average molecular weight is 51500 and Mw/Mn = 3.2.
Embodiment (6)
Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 62 molar %, sodium p-methallyl oxybenzene sulfonate as Unit B by 12 molar %, methyl acrylate as Unit C by 6 molar % and methoxy poly(p=45)ethylene glycol monomethacrylate as Unit D by 20 molar % (the total being 100 molar %), of which the weight average molecular weight is 38700 and Mw/Mn = 3.5.

8
Embodiment (1)
Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 70 molar %, sodium methallyl sulfonate as Unit B by 14 molar %, methyl acrylate as Unit C by 10 molar % and polyethylene glycol (p=90) monomethacrylate as Unit D by 6 molar % (the total being 100 molar %), of which the weight average molecular weight is 54800 and Mw/Mn = 5.1.
Embodiment (8)
Cement dispersant using water-soluble vinyl copolymer with sodium methacryiate as Unit A by 62 molar %, sodium methallyl sulfonate as Unit B by 12 molar %, methyl acrylate as Unit C by 12 molar %, methoxypolyethoxyethyt (n in Formula (7) = 68) methacrylate as Unit E by 8 molar % and methoxypolyethoxyethyl (m in Formula (8) = 9) methacrylate as Unit F by 6 molar % (the total being 100 molar %), of which the weight average molecular weight is 66600 and Mw/Mn = 4.5.
Embodiment (9)
Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 57 molar %, sodium methallyl sulfonate as Unit B by 15 molar %, methyl acrylate as Unit C by 14 molar %, methoxypolyethoxyethyl (n in Formula (7) = 68) methacrylate as Unit E by 10 molar % and methoxypolyethoxyethyl (m in Formula (8) = 23) methacrylate as Unit F by 2 molar % (the total being 100 molar %), of which the weight average molecular weight is 38500 andMw/Mn = 3.5.
Embodiment (10)
Cement dispersant using water-solubfe vinyl copolymer with sodium methacrylate as Unit A by 72 molar %, sodium methallyl sulfonate as Unit B by 8 molar %, methyl acrylate as Unit C by 5 molar %, methoxypolyethoxyethyl (n in Formula (7) = 95) methacrylate as Unit E by 4 molar % and methoxypolyethoxyethyl (m in Formula (8) = 9) methacrylate as Unit F by 11

9
molar % (the total being 100 molar %), of which the weight average molecular weight is 62900 and Mw/Mn = 3.4.
Embodiment (ll)
Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 65 molar %, sodium methallyl sulfonate as Unit B by 5 molar %, methyl acrylate as Unit C by 10 molar %, methoxypolyethoxyethyl (n in Formula (7) = 45) methacrylate as Unit E by 12 molar % and methoxypolyethoxyethyl (m in Formula (8) = 23) methacrylate as Unit F by 8 molar % (the total being 100 molar %), of which the weight average molecular weight is 114700 andMw/Mn = 3.1.
Embodiment (12)
Cement dispersant using water-soluble vinyl copolymer with sodium acrylate as Unit A by 70 molar %, sodium p-methallyl oxybenzene sulfonate as Unit B by 10 molar %, methyl acrylate as Unit C by 6 molar %, isopropoxypolyethoxyethyl (n in Formula (7) = 55) acrylate as Unit E by 11 molar % and methoxypolyethoxyethyl (m in Formula (8) = 9) methacrylate as Unit F by 3 molar % (the total being 100 molar %), of which the weight average molecular weight is 89700 and Mw/Mn = 3.9.
Embodiment (13)
Cement dispersant using water-soluble vinyl copolymer with sodium methacrylate as Unit A by 58 molar %, sodium p-methallyl oxybenzene sulfonate as Unit B by 18 molar %, methyl acrylate as Unit C by 8 molar %} methoxypolyethoxyethyl (n in Formula (7) = 68) methacrylate as Unit E by 10 molar % and methoxypolyethoxyethyl (m in Formula (8) = 23) methacrylate as Unit F by 6 molar % (the total being 100 molar %), of which the weight average molecular weight is 51000 and Mw/Mn = 6.0.
Examples
The invention will be described next by way of examples but these examples are not intended to limit the scope of the invention. In what follows, "parts" shall mean "weight parts" and "%" shall mean "weight % excluding the weight of air", unless otherwise noted.
Part 1 (Synthesis of water-soluble vinyl copolymers)
Synthesis of Test Example 1
Methacrylic acid 103 parts (1.20 moles), sodium methallyl sulfonate 47 parts (0.29 moles), methyl acrylate 13 parts (0.15 moles), methoxypoly(p=45)ethylene glycol monomethacrylate 559

10
parts (0.27 moles) and water 1500 parts were placed inside a reactor vessel, and after a 30% water solution of sodium hydroxide 90 parts was added to adjust the pH and to obtain a uniform solution, the atmosphere was replaced with nitrogen gas. The pH was of the reacting system was 5.8. The temperature of the reacting system was maintained at 60 °C by means of a temperature bath and a polymerization process was started by adding a 20% water solution of sodium persulfate 30 parts by titration over 3 hours. The polymerization process was continued for 2 hours more to conclude the polymerization. Thereafter, a 30% water solution of sodium hydroxide 10 parts was added for complete neutralization to obtain a reaction product. After a portion of the product thus obtained was condensed inside an evaporator, it was precipitated and refined inside a mixed acetone/isopropanol solvent and dried to obtain water-soluble vinyl copolymer (Test Example 1). This water-soluble vinyl copolymer (Test Example 1) was analyzed by NMR, elemental analysis, titration method and GPC and was found to be a water-soluble vinyl copolymer having sodium methacrylate as Unit A by 63 molar %, sodium methallyl sulfonate as Unit B by 15 molar %, methyl acrylate as Unit C by 8 molar % and methoxypoly(p=45)ethylene glycol monomethacrylate as Unit D by 14 molar % (the total being 100 weight %), of which the weight average molecular weight was 42500 and Mw/Mn = 4.6.
Synthesis of Test Example 2
Methacrylic acid 153 parts (1.57 moles), sodium methallyl sulfonate 63 parts (0.40 moles), methyl acrylate 23 parts (0.27 moles), methoxypoly(p=68)ethylene glycol monomethacryiate 560 parts (0.18 moles) and water 1600 parts were placed inside a reactor vessel, and after a 30% water solution of sodium hydroxide 147 parts was added to adjust the pH and to obtain a uniform solution, the atmosphere was replaced with nitrogen gas. The pH was of the reacting system was 5.5. The temperature of the reacting system was maintained at 60°C by means of a temperature bath and a polymerization process was started by adding a 20% water solution of sodium persulfate 40 parts by titration over 3 hours. The polymerization process was continued for 3 hours more to conclude the polymerization. Thereafter, a 30% water solution of sodium hydroxide 63 parts was added for complete neutralization to obtain a reaction product. After a portion of the product thus obtained was condensed inside an evaporator, it was refined and dried by using a mixed solvent to obtain water-soluble vinyl copolymer (Test Example 2). This water-soluble vinyl copolymer (Test Example 2) was analyzed by NMR, elemental analysis, titration method and GPC and was found to be a water-soluble vinyl copolymer having sodium methacrylate as Unit A by 67 molar %, sodium methallyl sulfonate as Unit B by 15 molar %, methyl acrylate as Unit C by 11 molar % and methoxypoly(p=68)ethylene glycol monomethacrylate as Unit D by 7 molar % (the total being 100 weight %), of which the weight average molecular weight was 46000 and Mw/Mn = 4.8.

11
Synthesis of Test Examples 3-13
Water-soluble vinyl copolymers (Test Examples 3-13) were similarly obtained as explained above for the production of Test Examples 1 and 2. Their compositions are shown in Table 1.
Synthesis of Comparison Example 1
Methacrylic acid 103 parts (1.20 moles), sodium methallyl sulfonate 14 parts (0.086 moles), methoxypoly(p=45)ethylene glycol monomethacrylate 891 parts (0.428 moles) and water 2100 parts were placed inside a reactor vessel, and after a 30% water solution of sodium hydroxide 160 parts was added to adjust the pH and to obtain a uniform solution, the atmosphere was replaced with nitrogen gas. The pH was of the reacting system was 9.2. The temperature of the reacting system was maintained at 60°C by means of a temperature bath and a polymerization process was started by adding a 20% water solution of sodium persulfate 50 parts by titration over 3 hours to obtain a reaction product. After a portion of the product thus obtained was condensed inside an evaporator, it was refined and dried by using a mixed solvent to obtain water-soluble vinyl copofymer (Comparison Example 1). This water-soluble vinyl copolymer (Comparison Example 1) was analyzed similarly as explained above and was found to be a water-solubie vinyl copolymer having sodium methacrylate as Unit A by 70 molar %, sodium methallyl sulfonate as Unit B by 5 molar %, and methoxypoly(p-45)ethylene glycol monomethacrylate as Unit D by 25 molar % (the total being 100 weight %), of which the weight average molecular weight was 62500 and Mw/Mn = 8.3.
Synthesis of Comparison Examples 2-15
Water-soluble vinyl copolymers (Comparison Examples 2-15) were similarly obtained as explained above for the production of Comparison Example 1. Their compositions are shown in Table 2.

12
Table 1

Kinds and molar % of constituent Units WAMW Mw/Mn
Unit A UnitB Unii tC Unit D Unit E Unit F
Test Example:
1 A-l 63 B-l 15 C-l 8 D-l 14 - - 42500 4.6
2 A-l 67 B-l 15 C-l 11 D-2 7 - - 46000 4.8
3 A-l 72 B-l 9 C-l 14 D-3 5 - - 59000 5.7
4 A-l 60 B-l 5 C-l 10 D-l 25 - - 40700 4.3
5 A-2 55 B-2 15 C-l 3 D-l 27 - - 51500 3.2
6 A-l 62 B-2 12 C-l 6 D-l 20 - - 38700 3.5
7 A-l 70 B-l 14 C-l 10 D-4 6 - - 54800 5.1
8 A-l 62 B-l 12 C-l 12 E-l 8 F-l 6 66600 4.5
9 A-l 57 B-l 15 C-l 14 E-l 10 F-2 2 38500 3.5
10 A-l 72 B-l 8 C-l 5 E-2 4 F-l 11 62900 3:4
11 A-l 65 B-l 5 C-l 10 E-3 12 F-2 8 114700 3.1
12 A-2 70 B-2 10 C-l 6 E-4 11 F-l 3 89700 3.9
13 A-3 58 B-2 18 C-l 8 E-l 10 F-2 6 51000 6.0
In Table 1 and thereafter;
WAMW: Weight average molecular weight

13
Table 2
Kinds and molar % of constituent Units WAMW Mw/Mn
Unit A Unit B Unit C Unit D Unit E Unit F Others

In Tables 1 and 2:
A-l: Unit of sodium methacrylate
A-2: Unit of sodium acrylate
A-3: Unit of methacrylic acid
B-l: Unit of sodium methallyl sulfonate
B-2: Unit of sodium p-methallyl oxybenzene sulfonate
C-l: Unit of methyl acrylate
D-1: Unit of methoxy poly(p=45)ethylene glycol methacrylate
D-2: Unit of methoxy poly(p=68)ethylene glycol methacrylate
D-3: Unit of methoxy poly(p=90)ethylene glycol methacrylate
D-4: Unit of polyethylene glycol (p=90) monomethacrylate
E-l(D-2): Unit of methoxypolyethoxyethyl (n in Formula (7) = 68) methacrylate
E-2: Unit of methoxypolyethoxyethyl (n in Formula (7) = 95) methacrylate
E-3(D-1): Unit of methoxypolyethoxyethyl (n in Formula (7) = 45) methacrylate
E-4: Unit of isopropoxy polyethoxyethyl (n in Formula (7) = 55) acrylate
F-1: Unit of methoxypolyethoxyethyl (m in Formula (8) = 9) methacrylate
F-2: Unit of methoxypolyethoxyethyl (m in Formula (8) = 23) methacrylate
X-l: Unit of methoxypoly(p=150)ethylene glycol methacrylate
X-2: Unit of methoxypoly(p=3)ethylene glycol methacrylate
X-3: Unit of sodium styrene sulfonate
X-4; Unit of 2-hydroxyethyl methacrylate

14
Part 2 (Preparation and Evaluation of Concrete) Preparation of Concrete
Each of the test examples of concrete was prepared by placing ordinary portland cement (specific weight=3.16, Braine vaIue=33OO), fine aggregates (sand from Ooi River with specific weight=2.63) and coarse aggregates (crushed stone from Okazaki with specific weight=2.66) sequentially into a 50-liter pan-type forced kneading mixer under the conditions shown in Table 3 and kneaded for 15 seconds. Next, the cement dispersants prepared in Part 1 were added together with kneading water at a rate of 0.1 -1.5 weight % with respect to the cement converted to solid components such that the target slump value would be within the range of 21±lcm and the mixture was kneaded for 2 minutes. An agent for controlling the amount of air was kneaded in with water in each case such that the target air content would become 4.0-5.0%.

Table 3

Condition
of Water/ Cement Sand-Coarse Aggregate Used materials fke/m3 )
Preparation Ratio (%) Ratio
(%) Water Cement Fine aggregate Coarse aggregate
1
2 33 50 44 49 165 165 500 330 742 867 944 960
Evaluation of Concrete
For each of test and comparison examples, slump value (SV), air quantity (AQ), setting time and compression strength were measured according respectively to J1S-A1101, JIS-Al 128, JIS-A6204 and JIS-A1108 immediately after the kneading (t=0), 60 minutes later (t=60) and 90 minutes later (t=90). The results are shown in Tables 4-7. In these Tables, the numbers in parentheses following the test and comparison example numbers indicate the condition of preparation defined in Table 3. Slump ratio is defined as the percentage ratio of the slump value after 90 minutes to the slump value immediately after the kneading.
These tables clearly show that cement dispersants according to this invention can provide a high level of fluidity while limiting the slump loss, as well as a high early strength at the initial period of hardening.

15
Table 4

Test Cemen t t=0 t=60 t=90 Slump
No. dispersant Ratio
fft/ Kind Amount sv AQ SV AQ SV AQ (%)
(Part)(*l) (cm) (%) (cm) (%) (cm) (%)
Test Examoles
1 HI) 0.22 21.5 4.5 20.4 4.4 19.6 4.4 91.1
2 2(1) 0.20 21.7 4.8 20.7 4.6 19.8 4.5 91.2
3 3(1) 0.22 21.8 4.6 20.2 4.5 19.4 4.2 89.0
4 4(1) 0.27 21.5 4.5 21.0 4,3 19.9 4.0 92.5
5 5(1) 0.34 21.3 4.7 19.9 4.3 18.7 4,1 87.8
6 6(1) 0.28 21.5 4.4 20.6 4.2 19.5 4.0 90.7
7 7(1) 0.21 21.2 4.6 19.6 4.4 18.4 4.2 86.8
8 1(2) 0.19 21.4 4.6 20.3 4.5 19.9 4.3 89.2
9 2(2) 0.18 21.5 4.7 20.7 4.5 19.4 4.4 90.2
10 3(2) 0.20 21.7 4.6 20.1 4.3 18.8 4.3 86.6
11 4(2) 0.24 21.4 4.6 20.3 ' 4.5 19.5 4.5 91.1
12 5(2) 0.30 21.8 4.7 20.1 4.5 18.7 4.3 85.8
13 6(2) 0.24 21.4 4.6 20.7 4.5 19.3 4.3 90.2
14 7(2) 0.19 21.6 4.4 20.0 4.4 18.6 4.2 86.1
15 8(1) 0.18 21.7 4.6 20.5 4.4 20.2 4.3 93.1
16 9(1) 0.17 21.5 4.5 21.0 4.5 19.8 4.3 92.1
17 10(1) 0.21 21.4 4.6 20.9 4.4 20.4 4.4 95.3
18 11(1) 0.26 21.6 4.4 20.8 4.4 20.1 4.2 93.1
19 12(1) 0.24 21.3 4.7 20.4 4.3 19.7 4.1 92.5
20 13(1) 0.16 21.6 4.5 20.5 4.2 19.9 4.0 91.7
21 8(2) 0.15 21.5 4.4 20.7 4.2 19.4 4.2 90.2
22 9(2) 0.14 21.8 4.6 21.0 4.3 19.9 4.2 91.3
23 10(2) 0.22 21.6 4.5 21.1 4.5 20.2 4.3 92.5
24 11(2) 0.25 21.3 4.7 20.4 4.6 19.5 4.4 91.5
25 12(2) 0.23 21.7 4.8 20.3 4.5 19.7 4.3 90.8
26 13(2) 0.19 21.5 4.5 20.6 4.4 19.4 4.2 90.2
* 1: The amount of cement dispersant is shown as converted to solid components with respect to 100 parts of cement.
(1), (2): Condition No. for preparation of concrete

16
Table 5

Test Cemen t t=0 t=60 t=90 Slump
No. dispersant Ratio
Kind Amount SV AQ SV AQ SV AQ (%)
(Part)(*l) (cm) (%) (cm) (%) (cm) (%)
Comparison
Examples
27 1(1) 0.280 21.5 4.9 17.1 4.4 13.4 4.4 64.5
28 2(1) 0.30 21.7 4.6 16.0 4.5 12.1 4.2 57.9
29 3(1) 0.55 21.2 4.5 15.0 4.3 11.8 4.0 72.4
30 4(1) 0.45 21.3 4.4 17.7 4.1 15.2 4.1 76.7
31 5(1) 0.29 21.6 4.6 17.3 4.4 14.6 4.2 70.8
32 6(1) 0.60 21.2 4.8 16.4 4.6 12.9 4.2 60.7
33 7(1) 0.35 21.4 4.8 15.0 4.5 10.8 4.1 50.5
34 8(1) 0.43 21.6 4.6 13.8 4.6 9.2 4.4 47.9
35 9(1) 0.31 21.3 4.7 15.5 4.6 12.5 4.4 62.0
36 10(1) 0.95 21.2 4.8 14.5 4.6 10.7 4.3 45.0
37 11(1) 0.49 21.7 4.8 15.2 4.6 11.8 4.5 54.3
38 12(1) 0.47 21.4 4.6 15.7 4.4 12.0 4.1 56.1
39 1(2) 0.27 21.6 4.7 15.7 4.4 13.3 4.2 61.6
40 2(2) 0.29 21.3 4.6 15.0 4.3 o 10.1 4.1 47.4
41 3(2) 0.48 21.5 4.9 17.0 4.6 15.0 4.5 69.8
42 4(2) 0.42 21.8 4.5 17.2 4.4 15.6 4.3 71.6
43 5(2) 0.27 21.4 4.6 16.9 4.5 13.9 4.5 65.0
44 6(2) 0.58 21.7 4.5 13.5 4.4 11.2 4.2 51.6
45 7(2) 0.32 21.5 4.7 12.8 4.5 10.4 4.4 48.4
46 8(2) 0.40 21.4 4.8 12.0 4.7 9.2 4.2 43.0
47 9(2) 0.30 21.6 4.6 16.2 4.4 13.0 4.4 60.2
48 10(2) 0.90 21.7 4.8 12.1 4.5 9.1 4.4 41.9
49 11(2) 0.45 21.9 4.7 12.8 4.5 12.2 4.3 41.4
50 12(2) 0.42 21.3 4.9 13.0 4.4 11.4 4.1 53.5
51 13(1) 0.47 21.8 4.8 15.2 4.4 11.0 4.1 50.5
52 14(1) 0.36 21.5 4.6 14.4 4.3 10.3 4.3 47.9
53 15(1) 0.58 21.3 4.7 16.0 4.4 13.2 4.4 62.0
54 13(2) 0.53 21.6 4.6 12.8 4.5 10.4 4.3 48.1
55 14(2) 0.34 21.2 4.8 12.3 4.6 9.7 4.4 45.8
56 15(2) 0.50 21.5 4.5 16.7 4.5 13.2 4.3 61.4
57 o2(1) 0.76 21.7 4.6 11.2 4.2 9.0 4.0 41.4
*1: The amount of cement dispersant is shown as converted to solid components with respect to
100 parts of cement.
*2: Salt of high condensates of naphthalene sulfonic acid formaldehyde (Polefine 510-AN,
tradename of Takemoto Yushi Kabushiki Kaisha)
(1), (2): Condition No. for preparation of concrete

17
Table 6

Test Setting \ Time Compressive Strength (N/mm2)
No. Start End Time Time Time Time Time
(min) (min) (8h) (12h) (18h) (24h) (72h)
1 335 415 1.7 9.7 22.2 36.5 53.7
2 320 400 2.0 10.1 22.5 38.8 54.0
3 300 370 2.5 12.0 24.0 43.0 55.6
4 340 435 1.4 9.0 21.3 36.0 53.5
5 355 450 1.1 8.8 21.0 35.7 53.0
6 330 410 1.9 9.8 22.0 39.0 54.3
7 305 365 2.6 12.5 24.5 44.0 55.8
8 340 420 0.9 3.5 6.7 16.6 26.8
9 320 405 1.0 3.7 6.9 16.7 27.1
10 315 395 1.3 3.9 7.0 16.9 27.3
11 355 455 0.7 3.3 6.5 16.2 26.4
12 360 465 0.7 3.2 6.3 16.0 26.2
13 330 425 0.9 3.5 6.7 16.8 27.0
14 310 390 1.3 4.0 7.0 17.0 27.4
15 310 385 2.0 10.2 ¦ 22.5 38.6 53.8
16 300 375 2.4 12.0 24.0 43.5 55.7
17 330 405 1.7 9.6 22.0 36.2 54.0
18 335 420 1.5 9.3 21.7 35.7 53.0
19 330 410 1.7 9.5 22.1 36.0 53.1
20 305 390 2.2 11.8 24.0 43.6 55.6
21 320 410 1.0 3.7 6.8 16.6 26.9
22 310 395 1.2 3.9 7.0 16.8 27.2
23 355 450 0.8 3.4 6.5 16.4 26.5
24 360 460 0.7 3.4 6.6 16.5 26.5
25 350 445 0.8 3.6 6.5 16.7 26.6
26 335 420 0.9 3.5 6.6 16.6 26.7

18
Table 7

Test Setting , Time Compressive Strength (N/mm2)
No. Start End Time Time Time Time Time
(min) (min) (8h) (12h) (18h) (24h) (72h)
27 380 490 0.3 1.2 9.6 14.8 45.7
28 410 530 0.1 0.7 9.0 13.5 43.7
29 470 590 *3 0.1 2.9 6.6 42.5
30 430 550 *3 0,2 4.2 7.7 43.0
31 380 485 0.4 1.7 11.1 17.0 47.7
32 500 620 *3 *3 1.8 6.4 42.3
33 425 540 *3 0.5 4.3 8.0 44.5
34 450 580 *3 0.2 2.9 7.0 43.9
35 480 605 *3 *3 2.5 6.5 42.8
36 650 780 *3 ?3 *3 1.5 41.0
37 440 575 *3 *3 0.4 7.0 43.8
38 495 590 *3 *3 0.2 3.1 43.0
39 405 540 *3 0.2 3.1 8.5 22.0
40 420 560 ?3 *3 1.8 7.5 21.6
41 510 645 *3 *3 *3 2.7 19.7
42 450 590 *3 *3 *3 2.0 20.2
43 400 535 *3 0.3 3.5 10.0 23.4
44 535 690 *3 *3 *3 0.4 18.5
45 445 585 *3 *3 *3 3.6 21.2
46 480 620 *3 *3 *3 3.0 20.7
47 460 - 600 *3 *3 0.2 1.9 20.6
48 620 785 *3 *3 *3 *3 15.7
49 490 635 *3 ?3 *3 0.8 19.5
50 540 680 *3 *3 *3 *3 17.6
51 530 675 *3 *3 0.9 3.6 39.5
52 455 590 *3 0.2 2.7 6.3 41.5
53 550 695 *3 *3 0.4 2.5 35.5
54 540 690 *3 *3 *3 0.3 18.5
55 465 600 . *3 *3 *3 1.9 19.0
56 530 670 *3 *3 *3 0.5 19.8
57 360 445 0.7 3.0 16.2 28.9 51.7
*3: No measurement could be taken because there was no hardening.

19 WE CLAIM :
1. A method for the production of a cement dispersant comprising water-soluble

vinyl copolymers, in which the water-soluble vinyl copolymers is obtained by radical copolymerization of a mixture of a vinyl monomer to form Unit A having Formula (1), a vinyl monomer to form Unit B having Formula (2), a vinyl monomer to form Unit C having Formula (3) and a vinyl monomer to form Unit D having Formula (4) in the presence of a radical initiator in an aqueous solution, the obtained water-soluble vinyl copolymers having 40 to 80 molar % of the Unit A, 0.5 to 20 molar % of the Unit B, 0.2 to 18 molar % of the Unit C and 2 to 40 molar % of the Unit D, the total content of the Units A, B, C and D being 100 molar %, pullulan-converted weight-average molecular weight measured by Gel Permeation Chromatography (GPC) Method of the water-soluble vinyl copolymers being 15000 to 150000 and the ratio of the weight-average molecular weight to number-average molecular weight being 2 to 7, said Formulas (1) to (4) being given by:
(Formula 1) (Formula 2)

20

R2
I _ ( CH^-C ) -
I
COOCHa
R3
I - ( CH^-C ) -
I COOW\-OR*
(Formula 3)
(Formula 4)
where
R\ R2 and R3 are each H or CH3,
R4 is H or an alkyl group with 1 to 3 carbon atoms,
X is a group having Formula (5) or (6), said Formulas (5) and (6) being given by :
-SCW (Formulas)
-O-CsH4-S03M3 (Formula 6)
A is a residual group obtainable by removing all hydroxyl groups from
polyether diol with repetition number of oxyalkylene units being 5 to 109, the oxyalkylene
units consisting either only of oxyethylene units or of both oxyethylene and oxypropylene
units,
M1 is H, an alkali metal, an alkali earth metal, ammonium or an organic
amine, and
M2 and M3 are each an alkali metal, an alkali earth metal, ammonium or an
organic amine.

21

2. The method as claimed in claim 1, wherein the vinyl monomer to form the
Unit D consists of a vinyl monomer to form Unit E having Formula (7) and a vinyl
monomer to form Unit F having Formula (8) and the obtained water-soluble vinyl
copolymers contain 2 to 15 molar % of said Unit E and 0.5 to 15 molar % of said
Unit F, said formulas (7) and (8) being given by -

(Formula 7)
(Formula 8)
where
R5 is H or CH3, R6 is an alkyl group with 1 to 3 carbon atoms, n is an integer of 40 to 109 and m is an integer of 5 to 25.
3. The method as claimed in claim 2, wherein the obtained water-soluble vinyl
copolymers contain 55 to 72 molar % of said Unit A , 3 to 18 molar % of said Unit B,
3 to 15 molar % of said Unite, 3 to 12 molar % of said Unit E and 1 to 12 molar %
of said Unit F, with the total being 100 molar %.

22
4. The method as claimed in claim 1, wherein pullulan-converted weight-
average molecular weight measured by Gel Permeation Chromatography (GPC) Method
of the obtained water-soluble vinyl copolymers is 25000 to 70000 and the ratio of the
weight-average molecular weight to number-average molecular weight is 3 to 6.5
5. The method as claimed in claim 2, wherein pullulan-converted weight-
average molecular weight measured by Gel Permeation Chromatography (GPC) method
of the obtained water-soluble vinyl copolymers is 25000 to 70000 and the ratio of the
weight-average molecular weight to number-average molecular weight is 3 to 6.5.
6. The method as claimed in claim 3, wherein pullulan-converted weight-
average molecular weight measured by Gel Permeation Chromatography (GPC) method
of the obtained water-soluble vinyl copolymers is 25000 to 70000 and the ratio of the
weight-average molecular weight to number-average molecular weight is 3 to 6.5.
7. A method of producing concrete, said method comprising the step of mixing
cement aggregates, a cement dispersant and water such that concrete with water-to-
cement ratio of 20 to 45% is produced, said cement dispersant consisting of water-
soluble vinyl copolymers comprising 40 to 80 molar % of Unit A having Formula (1), 0.5
to 20 molar % of Unit B having Formula (2), 0.2 to 18 molar % of Unit C having
Formula (3) and 2 to 40 molar % of Unit D having Formula (4), total content of said
Units A, B, C and D being 100 molar %, said water-soluble vinyl copolymers having
weight-average molecular weight pullulan converted by GPC method 15000 to 150000
and ratio of weight average molecular weight to number-average molecular weight being
2 to 7, said Formulas (1) to (4) being given by :

23
R1

(Formula 1)
(Formula 2)
(Formula 3)
(Formula 4)
where
R\ R2 and R3 are each H or CH3,
R4 is H or an alky! group with 1 to 3 carbon atoms,
X is a group having Formula (5) or (6), said Formulas (5) and (6) being given by
-SO3M2 (Formula 5)
-O~CSH4-SO3M3 (Formula 6)

24
A is a residual group obtainable by removing all hydroxyl groups from polyether dioj with repetition number of oxyalkylene units being 5 to 109, the oxyalkylene units consisting either only of oxyethylene units or of both oxyethylene and oxypropylene units,
M1 is H, an alkali metal, an alkali earth metal, ammonium or an organic amine, and
M2 and M3 are each an alkali metal, an alkali earth metal, ammonium or an organic amine.
8. The method as claimed in claim 7, wherein said Unit D consists of Unit E
having Formula (7) and Unit F having Formula (8), and said water-soluble vinyl copolymers containing 2 to 15 molar % of said Unit E and said 0.5 to 15 molar % of Unit F, said Formulas (7) and (8) being given by -

(Formula 7)
(Formula 8)
where
Rs is H or CH3, Rs is an alkyl group with 1 to 3 carbon atoms, n is an integer of 40 to 109 and m is an integer of 5 to 25.

25
9. The method as claimed in claim 8, wherein the obtained water-soluble vinyl
copolymers contain 55 to 72 molar % of said Unit A, 3 to 18 molar % of said Unit B, 3 to 15 molar % of said Unit C, 3 to 12 molar of said Unit E and 1 to 12 molar % of said Unit F.
10. The method as claimed in claim 7, wherein said water-soluble vinyl
copolymers have weight-average molecular weight pullulan converted by Gel Permeation Chromatography (GPC) method 25000 to 70000 and the ratio of weight-average molecular weight to number-average molecular weight 3 to 6.5.
11. The method as claimed in claim 8, wherein said water-soluble vinyl
copolymers have weight-average molecular weight pullulan converted by Gel Permeation Chromatography (GPC) method 25000 to 70000 and the ratio of weight-average molecular weight to number-average molecular weight 3 to 6.5.
12. The method as claimed in claim 9, wherein said water-soluble vinyl
copolymers have weight-average molecular weight pullulan converted by Gel Permeation Chromatography (GPC) method 25000 to 70000 and the ratio of weight-average molecular weight to number-average molecular weight 3 to 6.5.

-26-
13. A method for the production of a cement dispersant, substantially as herein described, particularly with reference to and as illustrated in the foregoing examples.
14. A method of producing concrete, substantially as herein described, particularly with reference to and as illustrated in the foregoing examples.
A method for the production of a cement dispersant comprising water-soluble vinyl copolymers, in which the water-soluble vinyl copolymers is obtained by radical copolymerization of a mixture of a vinyl monomer to form Unit A, a vinyl monomer to form Unit B, a vinyl monomer to form Unit C, and a vinyl monomer to form Unit D in the presence of a radical initiator in an aqueous solution, the obtained water-soluble vinyl copolymers having 40 to 80 molar % of the Unit A, 0.5 to 20 molar % of the Unit B, 0.2 to 18 molar % of the Unit C and 2 to 40 molar % of the Unit D, the total content of the Units A, B, C and D being 100 molar %, pullulan-converted weight-average molecular weight measured by Gel Permeation Chromatography Method of the water-soluble vinyl copolymers being 15000 to 150000 and the ratio of the weight-average molecular weight to number-average molecular weight being 2 to 7. Unit A can be formed by sodium salt of acrylic acid. Unit B can be formed by sodium salt of methallyl sulfonic acid. Unit C can be formed by methyl acrylate. Unit D can be formed by methoxy polyethylene glycol methacrylate with oxyalkylene units including only oxyethylene units and their repetition number in the range of 26 to 95.

Documents:

« Previous Patent

Next Patent »

Patent Number

206356

Indian Patent Application Number

00121/CAL/1999

PG Journal Number

17/2007

Publication Date

27-Apr-2007

Grant Date

27-Apr-2007

Date of Filing

16-Feb-1999

Name of Patentee

TAKEMOTO YUSHI KABUSHIKI KAISHA

Applicant Address

2-5, MINATO-MACHI, GAMAGORI-SHI, AICHI-KEN, JAPAN, A JOINT STOCK COMPANY DULY ORGANISED UNDER THE LAWS OF JAPAN.

Inventors:

#	Inventor's Name	Inventor's Address
1	MITSUO KINOSHITA	308 SHIINOKI, TAMETO-CHO, TOYOKAWA-SHI, AICHI-KEN, JAPAN
2	KAZUHISA OKADA	1-5 MINAMITOBOI, KATAHARA-CHO, GAMAGORI-SHI, AICHI-KEN, JAPAN
3	MASAHIRO IIDA	37-12 AZA-NISHIHOWA, YAYOI-CHO, TOYOHASHI-SHI, AICHI-KEN, JAPAN

PCT International Classification Number

C04B 24/26

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	69482/1998	1998-03-03	Japan
2	267319/1998	1998-09-04	Japan