Title of Invention	COPOLYMERS BASED ON UNSATURATED MONO-OR DICARBOXYLIC ACID DERIVATIVES AND OXYALKYLENE GLYCOL ALKENYL ETHERS, PROCESSES FOR THEIR PREPARATION
Abstract	Copolymers based on unsaturated mono-or dicarboxylic acid derivatives, oxyalkylene glycol alkenyl ethers and optionally vinylic polyalkylene glycol or ester compounds are described and also their use as additives for aqueous suspensions based on mineral or bituminous binders, in particular cement, gypsum, lime, anhydrite, or other calcium sulphate-based binders, and based on pulverulent dispersion binders. The copolymers according to the invention impart to the aqueous binder suspensions a very good dispersing and liquefying action with, at the same time, simultaneous excellent processing properties. Moreover, the oxyalkylene glycol alkenyl ether according to the invention are industrially relatively simple and inexpensive to prepare and need comparatively low initiator concentrations in the copolymerization.

Title of Invention

COPOLYMERS BASED ON UNSATURATED MONO-OR DICARBOXYLIC ACID DERIVATIVES AND OXYALKYLENE GLYCOL ALKENYL ETHERS, PROCESSES FOR THEIR PREPARATION

Abstract

Copolymers based on unsaturated mono-or dicarboxylic acid derivatives, oxyalkylene glycol alkenyl ethers and optionally vinylic polyalkylene glycol or ester compounds are described and also their use as additives for aqueous suspensions based on mineral or bituminous binders, in particular cement, gypsum, lime, anhydrite, or other calcium sulphate-based binders, and based on pulverulent dispersion binders. The copolymers according to the invention impart to the aqueous binder suspensions a very good dispersing and liquefying action with, at the same time, simultaneous excellent processing properties. Moreover, the oxyalkylene glycol alkenyl ether according to the invention are industrially relatively simple and inexpensive to prepare and need comparatively low initiator concentrations in the copolymerization.

Full Text	Description The present invention relates to copolymers based on unsaturated mono- or dicarboxylic acid derivatives and oxyalkylene glycol alkenyl ethers, to processes for their preparation and to the use of these copolymers as additives for aqueous suspensions based on mineral or bituminous binders. It is known that additives in the form of dispersing agents are often added to aqueous suspensions of hydraulic binders for improving their processability, i.e. kneadability, spreadability, sprayability, pumpability or flowability. These additives, as a rule comprising ionic groups, are able to break up solid agglomerates, to disperse the particles formed and in this way to improve the processability, especially of highly concentrated suspensions. This effect is specifically utilized in the preparation of construction material mixtures, based on cement, lime and calcium sulphate-based hydraulic binders, if appropriate also as a mixture with organic (e.g. bituminous) fractions and furthermore for ceramic compounds, refractory compounds and oilfield construction materials. In order to convert these construction material mixtures based on the said binders into a ready-to-use, processable form, as a rule significantly more mixing water is necessary than would be necessary for the subsequent hydration or hardening process. The cavity content formed by the excess water later evaporating in the construction article leads to significantly worsened mechanical strengths and resistances. In order to reduce this excess water content in the case of a specified processing consistency and/or to improve the processability in the case of a specified water/binder ratio, additives are employed which are in general designated as water reduction or flow agents. As such agents, poly- condensation products based on naphthalene- or alkylnaphthalenesulphonic acids (cf. EP-A 214 412) or melamine-formaldehyde resins comprising sulphonic acid groups (cf. DE-C 16 71 017) are especially known. A disadvantage with these additives is the fact that their excellent liquefying action, in particular in concrete construction, only lasts for a short period of time. The decrease in the processability of concrete mixtures ("slump loss") in a short time can in particular lead to problems where there is a large period between preparation and installation of the fresh concrete, for example due to long conveyor and transport routes. An additional problem results with the application of such flow agents in mining and in the interior zone (plasterboard sheet drying, anhydrite flow coat applications, concrete finished part production), where the release of the toxic formaldehyde contained in the products due to preparation and thus considerable industrial hygiene pollution can occur. For this reason, it has also already been attempted instead of this to develop formaldehyde-free concrete flow agents from maleic acid monoesters and styrene, for example according to EP-A 306 449. The flow action of concrete mixtures can be maintained for an adequately long period of time with the aid of these additives, but the originally present, very high dispersing action is very rapidly lost after storage of the aqueous preparation of the flow agent, due to the hydrolysis of the polymeric ester. This problem does not occur according to EP-A 373 621 in flow agents consisting of alkylpolyethylene glycol allyl ethers and maleic anhydride. However, these products, similarly to those previously described, are surface- active compounds which introduce undesirably high contents of air pores into the concrete mixture, from which losses in the strength and resistance of the hardened construction material result. For this reason, it is necessary to add to the aqueous solutions of these polymer compounds antifoams, such as, for example, tributyl phosphate, silicone derivatives and various water-insoluble alcohols in the concentration range from 0.1 to 2% by weight based on the solids content. The mixing in of these components and the maintenance of a storage-stable homogeneous form of the corresponding formulations also itself then turns out to be quite difficult if these antifoams are added in the form of emulsions. As a result of the complete or at least partial incorporation of a defoaming or anti-air-introducing structural unit into the copolymer, the problem of demixing according to DE 195 13 126 A1 can be solved. It has been shown, however, that the high effectiveness and the low "slump- loss" of the copolymers described here often leads to inadequate 24 hour strengths of the concrete. Such copolymers, in particular, do not have the optimal properties, where with the lowest possible water content a particularly densely formed and therefore high-strength and highly resistant concrete should be produced and steam hardening (finished part industry) for the acceleration of the hardening process should be dispensed with. For the solution of this problem, according to DE 199 26 611 A1 copolymers of unsaturated mono- or dicarboxylic acid derivatives and oxyalkylene glycol alkenyl ethers were proposed, which at a low dose can long maintain the processability of highly concentrated construction material mixtures in practice, with a simultaneously increased strength in the hardened state of the construction material due to an extreme lowering of the water/binder ratio. However, it has proved disadvantageous that the corresponding copolymers can only be prepared with relatively short polymer chains and a comparatively low average molecular weight, which is why the dispersing action of these copolymers was not optimal hitherto. The present invention was therefore based on the object of making available novel copolymers which did not have the said disadvantages according to the prior art, but on account of long polymer chains and high average molecular weight show an improved dispersing and liquefying action. This object was achieved according to the invention by the copolymers according to Claim 1. It has in fact surprisingly been shown that the products according to the invention based on unsaturated mono- or dicarboxylic acid derivatives and oxyalkylene glycol alkenyl ethers impart a very good dispersing and liquefying action with, at the same time, excellent processing properties to aqueous binder suspensions. Moreover, the oxyalkylene glycol alkenyl ethers employed according to the invention are industrially relatively simple and inexpensive to prepare and need comparatively low initiator concentrations in copolymerization, which was likewise unforeseeable. The copolymers according to the present invention contain at least two, preferably three, structural groups a), b) and optionally c) and optionally d) and no other structural groups. The first structural group a) is a mono- or dicarboxylic acid derivative having the general formulae (la) and/or (lb). In the mono- or dicarboxylic acid derivative (la), R1 represents hydrogen or an aliphatic hydrocarbon radical having 1 to 20 C atoms, preferably a methyl group. X is H, -COOMa, -CO-O-(CmH2mO)n-R2 or -CO-NH-(CmH2mO)n-R2 with the following meaning for M, a, m, n and R2: M is hydrogen, a mono- or divalent metal cation (preferably a sodium, potassium, calcium or magnesium ion), ammonium, an organic amine radical, and a = ½ or 1, depending on whether M is a mono- or divalent cation. The organic amine radicals employed are preferably substituted ammonium groups which are derived from primary, secondary or tertiary C1-20-alkylamines, C1-20- alkanolamines, C5-8-cycloalkylamines and C8-14-arylamines. Examples of the corresponding amines are methylamine, dimethylamine, trimethylamine, ethanolamine, diethanolamine, triethanolamine, methyldiethanolamine, cyclohexylamine, dicyclohexylamine, phenylamine, diphenylamine in the protonated (ammonium) form. R2 is hydrogen, an aliphatic hydrocarbon radical having 1 to 20 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms, an aryl radical having 6 to 14 C atoms, which can optionally be additionally substituted, m = 2 to 4 and n = 0 to 200, preferably 1 to 150. The aliphatic hydrocarbons can in this case be linear or branched and saturated or unsaturated. Preferred cycloalkyl radicals are to be regarded as cyclopentyl or cyclohexyl radicals, preferred aryl radicals as phenyl or naphthyl radicals, which in particular can additionally be substituted by hydroxyl, carboxyl or sulphonic acid groups. Instead of or in addition to the mono- or dicarboxylic acid derivative according to formula (la), the structural group a) can also be present in cyclic form according to formula (lb), where Y can be = O (acid anhydride) or NR2 (acid imide) with the meaning designated above for R2. The second structural group b) corresponds to formula (II) where R3 = H, an aliphatic hydrocarbon radical having 1 to 6 C atoms, R4 = an aliphatic hydrocarbon radical having 1 to 6 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms and phenyl, R5 = H, an aliphatic hydrocarbon radical having 1 to 5 C atoms, R6, R7 independently from each other = H, an aliphatic hydrocarbon radical having 1 to 6 C atoms, p = 0 to 3, q + r = 0 to 500 and R2 has the abovementioned meaning. According to a preferred embodiment, p in formula (II) can be 0; i.e. vinyl polyalkoxylates are concerned. The third structural group c) corresponds to the formulae (IlIa) or (IIIb) In formula (Ilia), R8 can be = H or CH3, depending on whether acrylic or methacrylic acid derivatives are concerned. Q can in this case be -H, -COOM a, or -COOR9, where a and M have the abovementioned meaning and R9 can be * an aliphatic hydrocarbon radical having 3 to 20 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms or an aryl radical having 6 to 14 C atoms. The aliphatic hydrocarbon radical can likewise be linear or branched, saturated or unsaturated. The preferred cycloaliphatic hydrocarbon radicals are in turn cyclopentyl or cyclohexyl radicals and the preferred aryl radicals phenyl or naphthyl radicals. If T = -COOR9, Q = -COOaM or -COOR9. In the case where T and Q = -COOR9, the corresponding structural groups are derived from the dicarboxylic acid esters. In addition to these ester structural units, the structural groups c) can have still other hydrophobic structural elements. These include the polypropylene oxide and polypropylene oxide-polyethylene oxide derivatives with x in this case assumes a value from 1 to 150 and y from 0 to 15. The alkylene oxide derivatives can in this case be linked via a group U1 to the alkyl radical of the structural group c) according to formula (IlIa), where U1 can be = -CO-NH-, -O- or -CH2-O-. In this case, the corresponding amide, vinyl or allyl ethers of the structural group according to formula (IlIa) are concerned. R10 can in this case in turn be R2 (for meaning of R2 see above) or where U2 can be = -NH-CO-, -O-, or -OCH2- and Q has the meaning described above. These compounds are polyalkylene oxide derivatives of the bifunctional alkenyl compounds according to formula (IlIa). As further hydrophobic structural elements, the structural groups c) can additionally contain compounds according to the formula (IlIa) having T = (CH2)2-V-(CH2)2-CH=CH-R2, where z = 0 to 4 and V can be an -O-CO-C6H4-CO-O-radical and R2 has the meaning indicated above. In this case, the corresponding difunctional ethylene compounds according to the formula (IlIa) are concerned, which are linked to one another via ester groups of the formula -O-CO-C6H4-CO-O- and where only one ethylene group has been copolymerized. These compounds are derived from the corresponding dialkenylphenyldicarboxylic acid esters. It is also possible in the context of the present invention that not only one, but both ethylene groups of the difunctional ethylene compounds have been copolymerized. This corresponds essentially to the structural groups according to the formula (IIlb) where R2, V and z have the meaning already described. It is to be regarded as essential to the invention that the copolymers contain 10 to 90 mol% of structural groups of the formulae (la) and/or (lb), 1 to 89 mol% of structural groups of the formula (II), 0 to 10 mol% of structural groups of the formulae (IlIa) and/or (IIIb). Preferably, these polymers contain 40 to 75 mol% of structural groups of the formulae (la) and/or (lb), 20 to 55 mol% of structural groups of the formula (II), 1 to 5 mol% of structural groups of the formulae (IlIa) and/or (lllb). According to a preferred embodiment, the copolymers according to the invention additionally contain up to 50 mol%, in particular up to 20 mol% based on the sum of the structural groups a) to c), of structures which are based on monomers based on vinyl- or (meth)acrylic acid derivatives such as styrene, α-methylstyrene, vinyl acetate, vinyl propionate, ethylene, propylene, isobutene, N-vinylpyrrolidone, allylsulphonic acid, methallylsulphonic acid, vinylsulphonic acid or vinylphosphonic acid. Preferred monomeric (meth)acrylic acid derivatives are hydroxyalkyl (meth)acrylate, acrylamide, methacrylamide, AMPS, methyl methacrylate, methyl acrylate, butyl acrylate or cyclohexyl acrylate. The number of repeating structural units in the copolymers is not restricted. It has proved particularly advantageous, however, to set average molecular weights of 5000 to 100 000 g/mol. The preparation of the copolymers according to the invention can be carried out in various ways. It is important in this case that 10 to 90 mol% of an unsaturated mono- or dicarboxylic acid derivative, 1 to 89 mol% of an oxyalkylene alkenyl ether and 0 to 10 mol% of a vinylic polyalkylene glycol or ester compound are polymerized with the aid of a free-radical starter. Unsaturated mono- or dicarboxylic acid derivatives which form the structural groups of the formulae (la) and (lb) preferably employed are: acrylic acid, methacrylic acid, maleic acid or fumaric acid. Instead of acrylic acid, methacrylic acid, maleic acid or fumaric acid, their mono- or divalent metal salts, preferably sodium, potassium, calcium or ammonium salts, can also be used. As the acrylic, methacrylic, maleic acid or fumaric acid, derivatives are especially used esters thereof with a polyalkylene glycol of the general formula HO-(CmH2mO)n-R2 having R2 = H, an aliphatic hydrocarbon radical having 1 to 20 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms, an optionally substituted aryl radical having 6 to 14 C atoms and m = 2 to 4 and n = 0 to 200. The preferred substituents on the aryl radical are -OH, -COOe or -SO3e groups. Instead of maleic acid, its anhydride or imide can also be used. The derivatives of the formulae (la) and (lb) can also be present as a mixture of anhydride or imide and free acid and are used in an amount of preferably 40 to 75 mol%. The second component essential to the invention for the preparation of the copolymers according to the invention is an oxyalkylene glycol alkenyl ether, which is preferably employed in an amount from 20 to 55 mol%. In the preferred oxyalkylene glycol alkenyl ethers according to the formula (V) R3 = H or is an aliphatic hydrocarbon radical having 1 to 6 C atoms, R4 is an aliphatic hydrocarbon radical having 1 to 6 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms and phenyl, R5 = H, an aliphatic hydrocarbon radical having 1 to 5 C atoms, R6 and R7 independently from each other = H, an aliphatic hydrocarbon radical having 1 to 6 C atoms, p = 0 to 3, q + r = 0 to 500, while R2 has the abovementioned meaning. In this case, the use of propenyloxy-polyalkylene glycol derivatives, which can be prepared very simply by rearrangement of the corresponding allyl polyethers, has proved particularly advantageous. 1 to 5 mol% of a vinylic polyalkylene glycol or ester compound are preferably employed as the third optional component for the introduction of the structural group c). The most preferred vinylic polyalkylene glycol compounds used are derivatives according to the formula (VI), where Q can preferably be -H, or -COO,MR8 = H, CH3 and U1 = -CO-NH-, -O- or -CH2O-, i.e. the acid amide, vinyl or allyl ether of the corresponding polyalkylene glycol derivatives is concerned. The values for x are 1 to 150 and for y = 0 to 15. R10 can either again be R2 or where U2 = -NH-CO-, -O- and -OCH2- and Q = -COOaM and is preferably -H. If R10 = R2 and R2 is preferably H, the polyalkylene glycol monoamides or ethers of the corresponding acrylic (Q = H, R8 = H), methacrylic (Q = H, R8 = CH3) or maleic acid (Q = -COO M-R8 = H) derivatives are concerned. Examples of such monomers are maleic acid N-(methylpolypropylene glycol) monoamide, maleic acid N-(methoxypolypropylene glycol polyethylene glycol) monoamide, polypropylene glycol vinyl ether and polypropylene glycol allyl ether. If R10 = R2, Afunctional vinyl compounds are concerned whose polyalkylene glycol derivatives are bonded to one another by means of amide or ether groups (-O- or -OCH2-). Examples of such compounds are polypropylene glycol bismaleic amide acid, polypropylene glycol diacrylamide, polypropylene glycol dimethacrylamide, polypropylene glycol divinyl ether, polypropylene glycol diallyl ether. The vinyl ester compound employed in the context of the present invention is preferably derivatives according to the formula (VII), where Q = -COO M or-COOR9 and R9 can be an aliphatic hydrocarbon radical having 3 to 20 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms and an aryl radical having 6 to 14 C atoms; a and M have the above-mentioned meaning. Examples of such ester compounds are di-n-butyl maleate or fumarate or mono-n-butyl maleate or fumarate. In addition, compounds according to the formula (VIII) can also be employed where z in turn can be 0 to 4 and R2 has the already known meaning. V is in this case -O-CO-C6H4-CO-O-. These compounds are, for example, dialkenylphthalic acid derivatives. A typical example of such phthalic acid derivatives is diallyl phthalate. The molecular weights of the compounds which form the structural group c) can be varied within wide limits and are preferably between 150 and 10 000. According to the invention, it is possible according to a preferred embodiment for additionally up to 50, preferably up to 20, mol%, based on the sum of the structural groups a) to c), of further monomers as described above to be employed. The copolymers according to the present invention can be prepared by the customary methods. A particular advantage according to the invention consists in the fact that it is possible to work without solvent or else in aqueous solution. In both cases, reactions which are pressureless and therefore quite safe in terms of safety are concerned. If the process is carried out in aqueous solution, the polymerization takes place at 20 to 100°C with the aid of a customary free-radical starter, the concentration of the aqueous solution preferably being adjusted to 30 to 50% by weight. According to a preferred embodiment, the free-radical polymerization can in this case be carried out in the acidic pH range, in particular at a pH between 4.0 and 6.5, where use can be made of the conventional initiators such as H2O2 without a feared ether cleavage occurring, by means of which the yields would be very severely reduced. In the process according to the invention, a procedure is preferably used such that the unsaturated mono- or dicarboxylic acid derivative which forms the structural group a) is introduced in partly neutralized form in aqueous solution, preferably together with the polymerization initiator, and the other monomers are metered in as soon as the necessary reaction temperature is reached in the receiver. The polymerization auxiliaries, which can lower the activation threshold of the preferably peroxidic initiator, are added separately such that the copolymerization can proceed at relatively low temperatures. According to a further preferred embodiment, the unsaturated mono- or dicarboxylic acid derivative and also the free-radical former can be metered in at separate or common inlets of the reactor receiver, by means of which the problem of heat dissipation can be solved in an ideal manner. On the other hand, it is also possible to introduce the polyalkylene glycol alkenyl ether forming the structural group b) and to meter in the mono- or dicarboxylic acid derivative (structural group a)) such that a uniform distribution of the monomer units over the polymer chain is achieved. The type of polymerization initiators, activators and other auxiliaries used, such as, for example, molecular weight regulators, is relatively unproblematical, i.e. the initiators used are the customary free-radical donors, such as hydrogen peroxide, sodium, potassium or ammonium peroxodisulphate, tert-butyl hydroperoxide, dibenzoyl peroxide, sodium peroxide, 2,2'-azobis(2-amidino-propane) dihydrochloride, azobis(isobutyronitrile) etc. If redox systems are used, the abovementioned initiators are combined with activators having a reducing action. Examples of such reducing agents are Fe(ll) salts, sodium hydroxymethanesulphinate dihydrate, alkali metal sulphites and metabisulphites, sodium hypophosphite, hydroxylamine hydrochloride, thiourea etc. A particular advantage of the copolymers according to the invention is the fact that they can also be prepared without solvent, which can take place with the aid of the customary free-radical starters at temperatures between 20 and 150°C. For economical reasons, this variant can in particular be used when the copolymers according to the invention are to be supplied directly to their use according to the invention in anhydrous form, because then a laborious removal of the solvent, in particular of the water (for example by spray drying) can be omitted. The copolymers according to the invention are outstandingly suitable as additives for aqueous suspensions of inorganic and organic solids based on mineral or bituminous binders such as cement, gypsum, lime, anhydrite or other calcium sulphate-based construction materials, or based on pulverulent dispersion binders, where they are employed in an amount from 0.01 to 10% by weight, in particular 0.1 to 5% by weight, based on the weight of the mineral binder. The following examples are intended to explain the invention in more detail. Examples Preparation examples Example 1 500.0 g (1.00 mol) of propenyloxypolyethylene glycol of the general formula (II) (average molecular weight 500 g/mol) were introduced into a 51 double- walled reaction vessel containing a thermometer, stirrer, reflux condenser and two entries for separate feeds. 2.28 g (0.01 mol) of dibutyl maleate were stirred in and 500 g of tap water were subsequently added, a strongly alkaline aqueous solution of the vinyl ether being obtained. 350 mg of FeSO4 7H2O,1.99 g of 3-mercaptopropionic acid and 13.00 g of 50% strength aqueous hydrogen peroxide were added successively. Subsequently, 100.87 g (1.40 mol) of acrylic acid and 208.22 g (1.6 mol) of hydroxypropyl acrylate (HPA) dissolved in 350 g of tap water, comprising an additional regulator amount of 6.21 g of 3-mercaptopropionic acid, were added to the receiver mixture at room temperature over a period of 75 minutes. Separately to this, the metering of 85 ml of a 2% strength aqueous solution of Bruggolit™took place over a period of 100 minutes, the temperature increasing to a maximum of 36.5°C. After addition was complete, the mixture was stirred for a further 10 minutes and adjusted to a pH of 6.50 by addition of aqueous sodium hydroxide solution. The weight average molecular weight of the copolymer was 18800 g/mol. Example 2 500.0 g (1.00 mol) of propenyloxypolyethylene glycol 500 of the general formula (II) (average molecular weight 500 g/mol) were introduced into a 51 double-walled reaction vessel containing a thermometer, stirrer, reflux condenser and two entries for separate feeds. 2.28 g (0.01 mol) of dibutyl maleate were stirred in and 500 g of tap water were subsequently added, a strongly alkaline aqueous solution of the vinyl ether being obtained. 29.40 g (0.30 mol) of maleic anhydride dissolved in 68.6 g of water (corresponding to a 30% strength solution) and separately 5.43 g of 20% strength aqueous sodium hydroxide solution were added with stirring and cooling, the temperature being kept below 30°C. 310 mg of FeSO4 7H2O, 1.54 g of 3-mercaptopropionic acid and 11.00 g of 50% strength aqueous hydrogen peroxide were added successively. Subsequently, 100.87 g (1.40 mol) of acrylic acid dissolved in 150 g of tap water, comprising an additional regulator amount of 5.30 g of 3-mercaptopropionic acid, were added to the receiver mixture at room temperature over a period of 75 minutes. Separately to this, the metering of 72 ml of a 2% strength aqueous solution of Briiggolit™took place over a period of 100 minutes, the temperature rising to a maximum of 34.9°C. After addition was complete, the mixture was stirred for a further 10 minutes and adjusted to a pH of 6.50 by addition of aqueous sodium hydroxide solution. The weight average molecular weight of the copolymer was 20100 g/mol. Example 3 1100 g (1.00 mol) of propenyloxypolyethylene glycol 1100 of the general formula (II) (average molecular weight 1100 g/mol) were introduced as a melt at 70°C into a 51 double-walled reaction vessel containing a thermometer, stirrer, reflux condenser and two entries for separate feeds. 1100 g of tap water were added, a strongly alkaline aqueous solution of the vinyl ether being obtained. 19.60 g (0.20 mol) of maleic anhydride dissolved in 45.0 g of water (corresponding to a 30% strength solution) and separately 3.62 g of 20% strength aqueous sodium hydroxide solution were added with stirring and cooling, the temperature being kept below 30°C. Subsequently, 36.00 g (0.02 mol) of a reaction product of a butanol-started monofunctional NH2-terminated ethylene oxide/propylene oxide block polymer (EO 4, PO 27; molecular weight 1800 g/mol) with maleic anhydride were added with short-term intensive stirring and 310 mg of FeSO4 7H2O,1.60 g of 3-mercaptopropionic acid and 11.50 g of 50% strength aqueous hydrogen peroxide were added successively. Subsequently, 93.67 g (1.30 mol) of acrylic acid dissolved in 281 g of tap water comprising an additional regulator amount of 5.0 g of 3-mercaptopropionic acid were added to the receiver mixture at room temperature over a period of 75 minutes. Separately to this, the metering of 72 ml of a 2% strength aqueous solution of Bruggolit™ took place over a period of 97 minutes, the temperature rising to a maximum of 32.8°C. After addition was complete, the mixture was stirred for a further 15 minutes and adjusted to a pH of 6.50 by addition of aqueous sodium hydroxide solution. The weight average molecular weight of the copolymer was 30300 g/mol. Example 4 2000.0 g (1.00 mol) of propenyloxypolyethylene glycol 2000 of the general formula (II) (average molecular weight 2000 g/mol) were introduced as a melt at 50oC into a 5 I double-walled reaction vessel containing a thermometer. stirrer, reflux condenser and two entries for separate feeds. 4.56 g (0.02 mol) of dibutyl maleate were stirred into the melt and subsequently 2000 g of tap water were added, a strongly alkaline aqueous solution of the vinyl ether being obtained. Subsequently, 310 mg of FeSO4 7H2O, 1.99 g of 3-mercaptopropionic acid and 12.00 g of 50% strength aqueous hydrogen peroxide were added. Subsequently, 144.12 g (2.00 mol) of acrylic acid were mixed at room temperature with 350 g of tap water, an additional regulator amount of 4.31 g of 3-mercaptopropionic acid being contained. This was added to the receiver mixture over a period of 85 minutes. Separately to this, the metering of 78 ml of a 2% strength aqueous solution of Bruggolit™ took place over a period of 97 minutes, the temperature rising to a maximum of 31.1 °C. After addition was complete, the mixture was stirred for a further 10 minutes and adjusted to a pH of 6.50 by addition of aqueous sodium hydroxide solution. The weight average molecular weight of the copolymer was 33300 g/mol. Example 5 2000 g (1.00 mol) of propenyloxypolyethylene glycol 2000 of the general formula (II) (average molecular weight 2000 g/mol) were introduced as a melt at 85°C into a 51 double-walled reaction vessel containing a thermometer, stirrer, reflux condenser and two entries for separate feeds. Subsequently, 2000 g of tap water were added, a strongly alkaline aqueous solution of the vinyl ether being obtained. 58.80 g (0.60 mol) of maleic anhydride dissolved in 137.2 g of water (corresponding to a 30% strength solution) and separately 10.86 g of 20% strength aqueous sodium hydroxide solution were added with stirring and cooling, the temperature being kept below 30°C. Subsequently, 36.00 g (0.02 mol) of a reaction product of a butanol-started monofunctional NH2-terminated ethylene oxide/propylene oxide block polymer (EO 4, PO 27; molecular weight 1800 g) with maleic anhydride were added with short-term intensive stirring. Subsequently, 380 mg of FeSO4 7H2O, 2.33 g of 3-mercaptopropionic acid and 13.50 g of 50% strength aqueous hydrogen peroxide were added. Subsequently, 128.27 g (1.78 mol) of acrylic acid dissolved in 350 g of tap water comprising an additional regulator amount of 6.31 g of 3-mercaptopropionic acid were added to the receiver mixture at room temperature over a period of 85 minutes. Separately to this, the metering of 91 ml of a 2% strength aqueous solution of Brtiggolit™took place over a period of 97 minutes, the temperature rising to a maximum of 30.9°C. After addition was complete, the mixture was stirred for a further 10 minutes and adjusted to a pH of 6.50 by addition of aqueous sodium hydroxide solution. The weight average molecular weight of the copolymer was 31200 g/mol. Comparative examples Comparative example 1 The procedure was as described in Example 1, but instead of the propenyloxypolyethylene glycol of the general formula (II) used there a vinyloxybutylpoly(ethylene glycol) having the average molecular weight 500 g/mol was used. Otherwise, the same required amounts as in Example 1 were used. Comparative example 2 The procedure was as described in Example 5, but instead of the propenyloxypolyethylene glycol (MW = 2000) of the general formula (II) used there a vinyloxybutylpoly(ethylene glycol) having the average molecular weight 2000 g/mol was used. Use examples Use example 1 (Ready-mixed concrete) As standard, 4.5 kg of Portland cement (CEM 142.5 R Bernburg) were mixed with 33 kg of aggregates (grading curve 0 to 32 mm) and 2.7 kg of water including the water from the additive in a concrete mechanical mixer. The aqueous solutions of the additives were added and 10 minutes and 40 minutes after the beginning of the test the determination of the degree of spread was carried out according to DIN EN 12350-5. Test bodies of edge length 15x15x15 cm were subsequently prepared and the compressive strength after 24 hours and the air pore content were determined (by means of density of the hardened sample). � Use example 2 (Finished part concrete) Finished part formulation as described above, but 5.75 kg of Portland cement CEM I 52.5 R Bernburg, 2.3 kg of water and 33 kg of aggregate. WE CLAIM: 1. Copolymers based on unsaturated mono- or dicarboxylic acid derivatives and oxyalkylene glycol alkenyl ethers, comprising a) 10 to 90 mol% of the structural groups of at least one of the formulae (la) and (lb) where R1 = hydrogen or an aliphatic hydrocarbon radical having 1 to 20 C atoms X = H, -COOMa, -CO-O(CmH2mO) n-R2, -CO-NH-(CmH2mO)n-R2 M = hydrogen, a mono- or divalent metal cation, ammonium ion, an organic amine radical a = ½ or 1 R2 = hydrogen, an aliphatic hydrocarbon radical having 1 to 20 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms, an optionally substituted aryl radical having 6 to 14 C atoms Y = O, NR2 m =2 to 4 and N = 0 to 200, b) 1 to 89 mol% of structural groups of the general formula (II) where R3 = H, an aliphatic hydrocarbon radical having 1 to 6 C atoms R4 = an aliphatic hydrocarbon radical having 1 to 6 C atoms, a cycloaliphatic hydrocarbon radical having 1 to 6 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms and phenyl R5 = H, an aliphatic hydrocarbon radical having 1 to 5 C atoms R6, R7 = independently from each other H, an aliphatic hydrocarbon radical having 1 to 6 C atoms P =0 q + r = 0 to 500 and R2 has the abovementioned meaning c) 0 to 10 mol% of structural groups of at least one of the formulae (IlIa) and (lllb) where Q = -H, -COOMa, -COOR9 T =U1-(CH-CH2-O)x-(CH-CH2-O)y-R10/ -(CH2-V-(CH2)z-CH=CH-R2, -COOR9 if Q= -COOR9 or COOMa U1-CO-NH-Oo-CH2O- U2 = -NH-CO-,-O-,-OCH2- V = -O-CO-C6H4-CO-O- M = hydrogen, a mono- or divalent metal cation, ammonium ion, an organic amine radical R8= H,CH3 R9= an aliphatic hydrocarbon radical having 3 to 20 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms, an aryl radical having 6 to 14 C atoms R10= R2, -CH2-CH-U2-C=CH I I I R8 R8Q z =0 to 4 x = 1 to 150 y =0 to 15, and R2, R6 and R7 have the abovementioned meaning. 2. Copolymers as claimed in claim 1, wherein they additionally contain d) 0-50 mol% of structural groups (IV), the monomers of which represent a vinyl- or (meth) acrylic acid derivative. 3. Copolymers as claimed in claim 1, wherein R1 = hydrogen or a methyl radical. 4. Copolymers as claimed in claims 1 and 3, wherein M is a mono- or divalent metal cation selected from the group consisting of sodium, potassium, calcium or magnesium ions. 5. Copolymers as claimed in claims 1 to 4, wherein if R2 = phenyl the phenyl radical is additionally substituted by hydroxyl, carboxyl or sulphonic acid groups. 6. Copolymers as claimed in claims 1 to 5, wherein the formula (II) p = 0. 7. Copolymers as claimed in claims 1 to 6, wherein they contain 40 to 75 mol% of structural groups of the formulae (la) at least of (lb), 20 to 55 mol% of structural groups of the formula (II), 1 to 5 mol% of structural groups of the formulae (Ilia) at least of (Nib). 8. Copolymers as claimed in claims 1 to 7, wherein they additionally contain up to 50 mol%, in particular up to 20 mol%, based on the sum of the structural groups of the formulae (I), (II) and (III), of structural groups whose monomers are a vinyl- or (meth) acrylic acid derivative. 9. Copolymers as claimed in claims 2 and 8, wherein the monomeric vinyl derivative used was styrene, α-methylstyrene, vinyl acetate, vinyl propionate, ethylene, propylene, isobutene, N-vinylpyrrolidone, allylsulphonic acid, methallylsulphonic acid, vinylsulphonic acid or vinylphosphonic acid. 10. Copolymers as claimed in claims 2 and 8, wherein the monomeric (meth) acrylic acid derivative employed was hydroxyalkyl (meth) acrylamide, methacrylamide, AMPS, methyl methacrylate, methyl acrylate, butyl acrylate or cyclohexyl acrylate. 11. Copolymers as claimed in claims 1 to 10, wherein they have an average molecular weight of 5000 to 100000 g/mol. 12. Process for the preparation of the copolymers as claimed in claims 1 to 11, wherein 10 to 90 mol% of an unsaturated mono- or dicarboxylic acid derivative, 1 to 89 mol% of an oxyalkylene glycol alkenyl ether, 0 to 10 mol% of a vinylic polyalkylene glycol or ester compound are polymerized with the aid of a free-radical starter. 13. Process as claimed in claim 12, wherein 40 to 75 mol% of an unsaturated mono- or dicarboxylic acid derivative, 20 to 55 mol% of an oxyalkylene glycol alkenyl ether and 1 to 5 mol% of a vinylic polyalkylene glycol or ester compound are employed. 14. Process as claimed in claims 12 and 13, wherein additionally up to 50 mol%, in particular up to 20 mol%, based on the monomers having the structural groups as in the formulae(l), (II), (III) and (IV), of a vinyl or (meth) acrylic acid derivative are copolymerized. 15. Process as claimed in claims 12 and 13, wherein the polymerization is carried out in aqueous solution at a temperature of 20 to 100°C. 16. Process as claimed in claim 15, wherein the concentration of the aqueous solution is 30 to 50% by weight. 17. Process as claimed in claims 12 to 14, wherein the polymerization is carried out without solvent with the aid of a free-radical starter at temperatures of 20 to 150°C. 18. Copolymers as claimed in claims 1 to 11 as an additive for aqueous suspensions based on mineral or bituminous binders, in particular cement, gypsum, lime, anhydrite, or other calcium sulphate based binders and based on pulverulent dispersion binders. 19. Copolymers as claimed in claim 18 wherein they are employed in an amount from 0.01 to 10% by weight, preferably 0.1 to 5 % by weight, based on the weight of the mineral binder. ABSTRACT COPOLYMERS BASED ON UNSATURATED MONO-OR ICARBOXYLIC ACID DERIVATIVES AND OXYALKYLENE GLYCOL ALKENYL THERS, PROCESSES FOR THEIR PREPARATION Copolymers based on unsaturated mono-or dicarboxylic acid derivatives, oxyalkylene glycol alkenyl ethers and optionally vinylic polyalkylene glycol or ester compounds are described and also their use as additives for aqueous suspensions based on mineral or bituminous binders, in particular cement, gypsum, lime, anhydrite, or other calcium sulphate-based binders, and based on pulverulent dispersion binders. The copolymers according to the invention impart to the aqueous binder suspensions a very good dispersing and liquefying action with, at the same time, simultaneous excellent processing properties. Moreover, the oxyalkylene glycol alkenyl ether according to the invention are industrially relatively simple and inexpensive to prepare and need comparatively low initiator concentrations in the copolymerization.

Full Text

Description
The present invention relates to copolymers based on unsaturated mono- or
dicarboxylic acid derivatives and oxyalkylene glycol alkenyl ethers, to
processes for their preparation and to the use of these copolymers as
additives for aqueous suspensions based on mineral or bituminous binders.
It is known that additives in the form of dispersing agents are often added to
aqueous suspensions of hydraulic binders for improving their processability,
i.e. kneadability, spreadability, sprayability, pumpability or flowability. These
additives, as a rule comprising ionic groups, are able to break up solid
agglomerates, to disperse the particles formed and in this way to improve the
processability, especially of highly concentrated suspensions. This effect is
specifically utilized in the preparation of construction material mixtures, based
on cement, lime and calcium sulphate-based hydraulic binders, if appropriate
also as a mixture with organic (e.g. bituminous) fractions and furthermore for
ceramic compounds, refractory compounds and oilfield construction materials.
In order to convert these construction material mixtures based on the said
binders into a ready-to-use, processable form, as a rule significantly more
mixing water is necessary than would be necessary for the subsequent
hydration or hardening process. The cavity content formed by the excess
water later evaporating in the construction article leads to significantly
worsened mechanical strengths and resistances.
In order to reduce this excess water content in the case of a specified
processing consistency and/or to improve the processability in the case of a
specified water/binder ratio, additives are employed which are in general
designated as water reduction or flow agents. As such agents, poly-
condensation products based on naphthalene- or alkylnaphthalenesulphonic
acids (cf. EP-A 214 412) or melamine-formaldehyde resins comprising
sulphonic acid groups (cf. DE-C 16 71 017) are especially known.

A disadvantage with these additives is the fact that their excellent liquefying
action, in particular in concrete construction, only lasts for a short period of
time. The decrease in the processability of concrete mixtures ("slump loss") in
a short time can in particular lead to problems where there is a large period
between preparation and installation of the fresh concrete, for example due to
long conveyor and transport routes.
An additional problem results with the application of such flow agents in
mining and in the interior zone (plasterboard sheet drying, anhydrite flow coat
applications, concrete finished part production), where the release of the toxic
formaldehyde contained in the products due to preparation and thus
considerable industrial hygiene pollution can occur. For this reason, it has
also already been attempted instead of this to develop formaldehyde-free
concrete flow agents from maleic acid monoesters and styrene, for example
according to EP-A 306 449. The flow action of concrete mixtures can be
maintained for an adequately long period of time with the aid of these
additives, but the originally present, very high dispersing action is very rapidly
lost after storage of the aqueous preparation of the flow agent, due to the
hydrolysis of the polymeric ester.
This problem does not occur according to EP-A 373 621 in flow agents
consisting of alkylpolyethylene glycol allyl ethers and maleic anhydride.
However, these products, similarly to those previously described, are surface-
active compounds which introduce undesirably high contents of air pores into
the concrete mixture, from which losses in the strength and resistance of the
hardened construction material result.
For this reason, it is necessary to add to the aqueous solutions of these
polymer compounds antifoams, such as, for example, tributyl phosphate,
silicone derivatives and various water-insoluble alcohols in the concentration
range from 0.1 to 2% by weight based on the solids content. The mixing in of
these components and the maintenance of a storage-stable homogeneous

form of the corresponding formulations also itself then turns out to be quite
difficult if these antifoams are added in the form of emulsions.
As a result of the complete or at least partial incorporation of a defoaming or
anti-air-introducing structural unit into the copolymer, the problem of demixing
according to DE 195 13 126 A1 can be solved.
It has been shown, however, that the high effectiveness and the low "slump-
loss" of the copolymers described here often leads to inadequate 24 hour
strengths of the concrete. Such copolymers, in particular, do not have the
optimal properties, where with the lowest possible water content a particularly
densely formed and therefore high-strength and highly resistant concrete
should be produced and steam hardening (finished part industry) for the
acceleration of the hardening process should be dispensed with.
For the solution of this problem, according to DE 199 26 611 A1 copolymers of
unsaturated mono- or dicarboxylic acid derivatives and oxyalkylene glycol
alkenyl ethers were proposed, which at a low dose can long maintain the
processability of highly concentrated construction material mixtures in
practice, with a simultaneously increased strength in the hardened state of the
construction material due to an extreme lowering of the water/binder ratio.
However, it has proved disadvantageous that the corresponding copolymers
can only be prepared with relatively short polymer chains and a comparatively
low average molecular weight, which is why the dispersing action of these
copolymers was not optimal hitherto.
The present invention was therefore based on the object of making available
novel copolymers which did not have the said disadvantages according to the
prior art, but on account of long polymer chains and high average molecular
weight show an improved dispersing and liquefying action.
This object was achieved according to the invention by the copolymers
according to Claim 1. It has in fact surprisingly been shown that the products
according to the invention based on unsaturated mono- or dicarboxylic acid

derivatives and oxyalkylene glycol alkenyl ethers impart a very good
dispersing and liquefying action with, at the same time, excellent processing
properties to aqueous binder suspensions. Moreover, the oxyalkylene glycol
alkenyl ethers employed according to the invention are industrially relatively
simple and inexpensive to prepare and need comparatively low initiator
concentrations in copolymerization, which was likewise unforeseeable.
The copolymers according to the present invention contain at least two,
preferably three, structural groups a), b) and optionally c) and optionally d)
and no other structural groups. The first structural group a) is a mono- or
dicarboxylic acid derivative having the general formulae (la) and/or (lb).

In the mono- or dicarboxylic acid derivative (la), R1 represents hydrogen or an
aliphatic hydrocarbon radical having 1 to 20 C atoms, preferably a methyl
group. X is H, -COOMa, -CO-O-(CmH2mO)n-R2 or -CO-NH-(CmH2mO)n-R2 with
the following meaning for M, a, m, n and R2:
M is hydrogen, a mono- or divalent metal cation (preferably a sodium,
potassium, calcium or magnesium ion), ammonium, an organic amine radical,
and a = ½ or 1, depending on whether M is a mono- or divalent cation. The
organic amine radicals employed are preferably substituted ammonium groups
which are derived from primary, secondary or tertiary C1-20-alkylamines, C1-20-
alkanolamines, C5-8-cycloalkylamines and C8-14-arylamines. Examples of the
corresponding amines are methylamine, dimethylamine, trimethylamine,
ethanolamine, diethanolamine, triethanolamine, methyldiethanolamine,
cyclohexylamine, dicyclohexylamine, phenylamine, diphenylamine in the
protonated (ammonium) form.

R2 is hydrogen, an aliphatic hydrocarbon radical having 1 to 20 C atoms, a
cycloaliphatic hydrocarbon radical having 5 to 8 C atoms, an aryl radical
having 6 to 14 C atoms, which can optionally be additionally substituted, m = 2
to 4 and n = 0 to 200, preferably 1 to 150. The aliphatic hydrocarbons can in
this case be linear or branched and saturated or unsaturated. Preferred
cycloalkyl radicals are to be regarded as cyclopentyl or cyclohexyl radicals,
preferred aryl radicals as phenyl or naphthyl radicals, which in particular can
additionally be substituted by hydroxyl, carboxyl or sulphonic acid groups.
Instead of or in addition to the mono- or dicarboxylic acid derivative according
to formula (la), the structural group a) can also be present in cyclic form
according to formula (lb), where Y can be = O (acid anhydride) or NR2 (acid
imide) with the meaning designated above for R2.
The second structural group b) corresponds to formula (II)

where R3 = H, an aliphatic hydrocarbon radical having 1 to 6 C atoms, R4 = an
aliphatic hydrocarbon radical having 1 to 6 C atoms, a cycloaliphatic
hydrocarbon radical having 5 to 8 C atoms and phenyl, R5 = H, an aliphatic
hydrocarbon radical having 1 to 5 C atoms, R6, R7 independently from each
other = H, an aliphatic hydrocarbon radical having 1 to 6 C atoms, p = 0 to 3, q
+ r = 0 to 500 and R2 has the abovementioned meaning.
According to a preferred embodiment, p in formula (II) can be 0; i.e. vinyl
polyalkoxylates are concerned.

The third structural group c) corresponds to the formulae (IlIa) or (IIIb)

In formula (Ilia), R8 can be = H or CH3, depending on whether acrylic or
methacrylic acid derivatives are concerned. Q can in this case be -H, -COOM a,
or -COOR9, where a and M have the abovementioned meaning and R9 can be *
an aliphatic hydrocarbon radical having 3 to 20 C atoms, a cycloaliphatic
hydrocarbon radical having 5 to 8 C atoms or an aryl radical having 6 to 14 C
atoms. The aliphatic hydrocarbon radical can likewise be linear or branched,
saturated or unsaturated. The preferred cycloaliphatic hydrocarbon radicals
are in turn cyclopentyl or cyclohexyl radicals and the preferred aryl radicals
phenyl or naphthyl radicals. If T = -COOR9, Q = -COOaM or -COOR9. In the
case where T and Q = -COOR9, the corresponding structural groups are
derived from the dicarboxylic acid esters.
In addition to these ester structural units, the structural groups c) can have still
other hydrophobic structural elements. These include the polypropylene oxide
and polypropylene oxide-polyethylene oxide derivatives with

x in this case assumes a value from 1 to 150 and y from 0 to 15. The alkylene
oxide derivatives can in this case be linked via a group U1 to the alkyl radical
of the structural group c) according to formula (IlIa), where U1 can be =
-CO-NH-, -O- or -CH2-O-. In this case, the corresponding amide, vinyl or allyl

ethers of the structural group according to formula (IlIa) are concerned. R10
can in this case in turn be R2 (for meaning of R2 see above) or

where U2 can be = -NH-CO-, -O-, or -OCH2- and Q has the meaning described
above. These compounds are polyalkylene oxide derivatives of the
bifunctional alkenyl compounds according to formula (IlIa).
As further hydrophobic structural elements, the structural groups c) can
additionally contain compounds according to the formula (IlIa) having
T = (CH2)2-V-(CH2)2-CH=CH-R2, where z = 0 to 4 and V can be an
-O-CO-C6H4-CO-O-radical and R2 has the meaning indicated above. In this
case, the corresponding difunctional ethylene compounds according to the
formula (IlIa) are concerned, which are linked to one another via ester groups
of the formula -O-CO-C6H4-CO-O- and where only one ethylene group has
been copolymerized. These compounds are derived from the corresponding
dialkenylphenyldicarboxylic acid esters.
It is also possible in the context of the present invention that not only one, but
both ethylene groups of the difunctional ethylene compounds have been
copolymerized. This corresponds essentially to the structural groups
according to the formula (IIlb)

where R2, V and z have the meaning already described.

It is to be regarded as essential to the invention that the copolymers contain
10 to 90 mol% of structural groups of the formulae (la) and/or (lb), 1 to 89
mol% of structural groups of the formula (II), 0 to 10 mol% of structural groups
of the formulae (IlIa) and/or (IIIb).
Preferably, these polymers contain 40 to 75 mol% of structural groups of the
formulae (la) and/or (lb), 20 to 55 mol% of structural groups of the formula (II),
1 to 5 mol% of structural groups of the formulae (IlIa) and/or (lllb).
According to a preferred embodiment, the copolymers according to the
invention additionally contain up to 50 mol%, in particular up to 20 mol%
based on the sum of the structural groups a) to c), of structures which are
based on monomers based on vinyl- or (meth)acrylic acid derivatives such as
styrene, α-methylstyrene, vinyl acetate, vinyl propionate, ethylene, propylene,
isobutene, N-vinylpyrrolidone, allylsulphonic acid, methallylsulphonic acid,
vinylsulphonic acid or vinylphosphonic acid.
Preferred monomeric (meth)acrylic acid derivatives are hydroxyalkyl
(meth)acrylate, acrylamide, methacrylamide, AMPS, methyl methacrylate,
methyl acrylate, butyl acrylate or cyclohexyl acrylate.
The number of repeating structural units in the copolymers is not restricted. It
has proved particularly advantageous, however, to set average molecular
weights of 5000 to 100 000 g/mol.
The preparation of the copolymers according to the invention can be carried
out in various ways. It is important in this case that 10 to 90 mol% of an
unsaturated mono- or dicarboxylic acid derivative, 1 to 89 mol% of an
oxyalkylene alkenyl ether and 0 to 10 mol% of a vinylic polyalkylene glycol or
ester compound are polymerized with the aid of a free-radical starter.

Unsaturated mono- or dicarboxylic acid derivatives which form the structural
groups of the formulae (la) and (lb) preferably employed are: acrylic acid,
methacrylic acid, maleic acid or fumaric acid.
Instead of acrylic acid, methacrylic acid, maleic acid or fumaric acid, their
mono- or divalent metal salts, preferably sodium, potassium, calcium or
ammonium salts, can also be used.
As the acrylic, methacrylic, maleic acid or fumaric acid, derivatives are
especially used esters thereof with a polyalkylene glycol of the general
formula HO-(CmH2mO)n-R2 having R2 = H, an aliphatic hydrocarbon radical
having 1 to 20 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C
atoms, an optionally substituted aryl radical having 6 to 14 C atoms and m = 2
to 4 and n = 0 to 200.
The preferred substituents on the aryl radical are -OH, -COOe or -SO3e
groups.
Instead of maleic acid, its anhydride or imide can also be used. The
derivatives of the formulae (la) and (lb) can also be present as a mixture of
anhydride or imide and free acid and are used in an amount of preferably 40
to 75 mol%.
The second component essential to the invention for the preparation of the
copolymers according to the invention is an oxyalkylene glycol alkenyl ether,
which is preferably employed in an amount from 20 to 55 mol%. In the
preferred oxyalkylene glycol alkenyl ethers according to the formula (V)

R3 = H or is an aliphatic hydrocarbon radical having 1 to 6 C atoms, R4 is an
aliphatic hydrocarbon radical having 1 to 6 C atoms, a cycloaliphatic
hydrocarbon radical having 5 to 8 C atoms and phenyl, R5 = H, an aliphatic
hydrocarbon radical having 1 to 5 C atoms, R6 and R7 independently from
each other = H, an aliphatic hydrocarbon radical having 1 to 6 C atoms, p = 0
to 3, q + r = 0 to 500, while R2 has the abovementioned meaning. In this case,
the use of propenyloxy-polyalkylene glycol derivatives, which can be prepared
very simply by rearrangement of the corresponding allyl polyethers, has
proved particularly advantageous.
1 to 5 mol% of a vinylic polyalkylene glycol or ester compound are preferably
employed as the third optional component for the introduction of the structural
group c). The most preferred vinylic polyalkylene glycol compounds used are
derivatives according to the formula (VI),

where Q can preferably be -H, or -COO,MR8 = H, CH3 and U1 = -CO-NH-, -O-
or -CH2O-, i.e. the acid amide, vinyl or allyl ether of the corresponding
polyalkylene glycol derivatives is concerned. The values for x are 1 to 150 and
for y = 0 to 15. R10 can either again be R2 or

where U2 = -NH-CO-, -O- and -OCH2- and Q = -COOaM and is preferably -H.

If R10 = R2 and R2 is preferably H, the polyalkylene glycol monoamides or
ethers of the corresponding acrylic (Q = H, R8 = H), methacrylic (Q = H, R8 =
CH3) or maleic acid (Q = -COO M-R8 = H) derivatives are concerned.
Examples of such monomers are maleic acid N-(methylpolypropylene glycol)
monoamide, maleic acid N-(methoxypolypropylene glycol polyethylene glycol)
monoamide, polypropylene glycol vinyl ether and polypropylene glycol allyl
ether.
If R10 = R2, Afunctional vinyl compounds are concerned whose polyalkylene
glycol derivatives are bonded to one another by means of amide or ether
groups (-O- or -OCH2-). Examples of such compounds are polypropylene
glycol bismaleic amide acid, polypropylene glycol diacrylamide, polypropylene
glycol dimethacrylamide, polypropylene glycol divinyl ether, polypropylene
glycol diallyl ether.
The vinyl ester compound employed in the context of the present invention is
preferably derivatives according to the formula (VII),

where Q = -COO M or-COOR9 and R9 can be an aliphatic hydrocarbon
radical having 3 to 20 C atoms, a cycloaliphatic hydrocarbon radical having 5
to 8 C atoms and an aryl radical having 6 to 14 C atoms; a and M have the
above-mentioned meaning. Examples of such ester compounds are di-n-butyl
maleate or fumarate or mono-n-butyl maleate or fumarate.
In addition, compounds according to the formula (VIII) can also be employed

where z in turn can be 0 to 4 and R2 has the already known meaning. V is in
this case -O-CO-C6H4-CO-O-. These compounds are, for example,
dialkenylphthalic acid derivatives. A typical example of such phthalic acid
derivatives is diallyl phthalate.
The molecular weights of the compounds which form the structural group c)
can be varied within wide limits and are preferably between 150 and 10 000.
According to the invention, it is possible according to a preferred embodiment
for additionally up to 50, preferably up to 20, mol%, based on the sum of the
structural groups a) to c), of further monomers as described above to be
employed.
The copolymers according to the present invention can be prepared by the
customary methods. A particular advantage according to the invention
consists in the fact that it is possible to work without solvent or else in
aqueous solution. In both cases, reactions which are pressureless and
therefore quite safe in terms of safety are concerned.
If the process is carried out in aqueous solution, the polymerization takes
place at 20 to 100°C with the aid of a customary free-radical starter, the
concentration of the aqueous solution preferably being adjusted to 30 to 50%
by weight. According to a preferred embodiment, the free-radical
polymerization can in this case be carried out in the acidic pH range, in
particular at a pH between 4.0 and 6.5, where use can be made of the
conventional initiators such as H2O2 without a feared ether cleavage occurring,
by means of which the yields would be very severely reduced.

In the process according to the invention, a procedure is preferably used such
that the unsaturated mono- or dicarboxylic acid derivative which forms the
structural group a) is introduced in partly neutralized form in aqueous solution,
preferably together with the polymerization initiator, and the other monomers
are metered in as soon as the necessary reaction temperature is reached in
the receiver. The polymerization auxiliaries, which can lower the activation
threshold of the preferably peroxidic initiator, are added separately such that
the copolymerization can proceed at relatively low temperatures. According to
a further preferred embodiment, the unsaturated mono- or dicarboxylic acid
derivative and also the free-radical former can be metered in at separate or
common inlets of the reactor receiver, by means of which the problem of heat
dissipation can be solved in an ideal manner.
On the other hand, it is also possible to introduce the polyalkylene glycol
alkenyl ether forming the structural group b) and to meter in the mono- or
dicarboxylic acid derivative (structural group a)) such that a uniform
distribution of the monomer units over the polymer chain is achieved.
The type of polymerization initiators, activators and other auxiliaries used,
such as, for example, molecular weight regulators, is relatively
unproblematical, i.e. the initiators used are the customary free-radical donors,
such as hydrogen peroxide, sodium, potassium or ammonium
peroxodisulphate, tert-butyl hydroperoxide, dibenzoyl peroxide, sodium
peroxide, 2,2'-azobis(2-amidino-propane) dihydrochloride,
azobis(isobutyronitrile) etc. If redox systems are used, the abovementioned
initiators are combined with activators having a reducing action. Examples of
such reducing agents are Fe(ll) salts, sodium hydroxymethanesulphinate
dihydrate, alkali metal sulphites and metabisulphites, sodium hypophosphite,
hydroxylamine hydrochloride, thiourea etc.
A particular advantage of the copolymers according to the invention is the fact
that they can also be prepared without solvent, which can take place with the
aid of the customary free-radical starters at temperatures between 20 and

150°C. For economical reasons, this variant can in particular be used when
the copolymers according to the invention are to be supplied directly to their
use according to the invention in anhydrous form, because then a laborious
removal of the solvent, in particular of the water (for example by spray drying)
can be omitted.
The copolymers according to the invention are outstandingly suitable as
additives for aqueous suspensions of inorganic and organic solids based on
mineral or bituminous binders such as cement, gypsum, lime, anhydrite or
other calcium sulphate-based construction materials, or based on pulverulent
dispersion binders, where they are employed in an amount from 0.01 to 10%
by weight, in particular 0.1 to 5% by weight, based on the weight of the
mineral binder.
The following examples are intended to explain the invention in more detail.
Examples
Preparation examples
Example 1
500.0 g (1.00 mol) of propenyloxypolyethylene glycol of the general formula
(II) (average molecular weight 500 g/mol) were introduced into a 51 double-
walled reaction vessel containing a thermometer, stirrer, reflux condenser and
two entries for separate feeds.
2.28 g (0.01 mol) of dibutyl maleate were stirred in and 500 g of tap water
were subsequently added, a strongly alkaline aqueous solution of the vinyl
ether being obtained.
350 mg of FeSO4 7H2O,1.99 g of 3-mercaptopropionic acid and 13.00 g of
50% strength aqueous hydrogen peroxide were added successively.
Subsequently, 100.87 g (1.40 mol) of acrylic acid and 208.22 g (1.6 mol) of
hydroxypropyl acrylate (HPA) dissolved in 350 g of tap water, comprising an

additional regulator amount of 6.21 g of 3-mercaptopropionic acid, were added
to the receiver mixture at room temperature over a period of 75 minutes.
Separately to this, the metering of 85 ml of a 2% strength aqueous solution of
Bruggolit™took place over a period of 100 minutes, the temperature
increasing to a maximum of 36.5°C.
After addition was complete, the mixture was stirred for a further 10 minutes
and adjusted to a pH of 6.50 by addition of aqueous sodium hydroxide
solution. The weight average molecular weight of the copolymer was
18800 g/mol.
Example 2
500.0 g (1.00 mol) of propenyloxypolyethylene glycol 500 of the general
formula (II) (average molecular weight 500 g/mol) were introduced into a 51
double-walled reaction vessel containing a thermometer, stirrer, reflux
condenser and two entries for separate feeds.
2.28 g (0.01 mol) of dibutyl maleate were stirred in and 500 g of tap water
were subsequently added, a strongly alkaline aqueous solution of the vinyl
ether being obtained.
29.40 g (0.30 mol) of maleic anhydride dissolved in 68.6 g of water
(corresponding to a 30% strength solution) and separately 5.43 g of 20%
strength aqueous sodium hydroxide solution were added with stirring and
cooling, the temperature being kept below 30°C. 310 mg of FeSO4 7H2O,
1.54 g of 3-mercaptopropionic acid and 11.00 g of 50% strength aqueous
hydrogen peroxide were added successively. Subsequently, 100.87 g
(1.40 mol) of acrylic acid dissolved in 150 g of tap water, comprising an
additional regulator amount of 5.30 g of 3-mercaptopropionic acid, were added
to the receiver mixture at room temperature over a period of 75 minutes.
Separately to this, the metering of 72 ml of a 2% strength aqueous solution of
Briiggolit™took place over a period of 100 minutes, the temperature rising to
a maximum of 34.9°C.
After addition was complete, the mixture was stirred for a further 10 minutes
and adjusted to a pH of 6.50 by addition of aqueous sodium hydroxide

solution. The weight average molecular weight of the copolymer was 20100
g/mol.
Example 3
1100 g (1.00 mol) of propenyloxypolyethylene glycol 1100 of the general
formula (II) (average molecular weight 1100 g/mol) were introduced as a melt
at 70°C into a 51 double-walled reaction vessel containing a thermometer,
stirrer, reflux condenser and two entries for separate feeds.
1100 g of tap water were added, a strongly alkaline aqueous solution of the
vinyl ether being obtained. 19.60 g (0.20 mol) of maleic anhydride dissolved in
45.0 g of water (corresponding to a 30% strength solution) and separately
3.62 g of 20% strength aqueous sodium hydroxide solution were added with
stirring and cooling, the temperature being kept below 30°C.
Subsequently, 36.00 g (0.02 mol) of a reaction product of a butanol-started
monofunctional NH2-terminated ethylene oxide/propylene oxide block polymer
(EO 4, PO 27; molecular weight 1800 g/mol) with maleic anhydride were
added with short-term intensive stirring and 310 mg of FeSO4 7H2O,1.60 g of
3-mercaptopropionic acid and 11.50 g of 50% strength aqueous hydrogen
peroxide were added successively. Subsequently, 93.67 g (1.30 mol) of acrylic
acid dissolved in 281 g of tap water comprising an additional regulator amount
of 5.0 g of 3-mercaptopropionic acid were added to the receiver mixture at
room temperature over a period of 75 minutes. Separately to this, the metering
of 72 ml of a 2% strength aqueous solution of Bruggolit™ took place over a
period of 97 minutes, the temperature rising to a maximum of 32.8°C.
After addition was complete, the mixture was stirred for a further 15 minutes
and adjusted to a pH of 6.50 by addition of aqueous sodium hydroxide
solution. The weight average molecular weight of the copolymer was 30300
g/mol.
Example 4
2000.0 g (1.00 mol) of propenyloxypolyethylene glycol 2000 of the general
formula (II) (average molecular weight 2000 g/mol) were introduced as a melt
at 50oC into a 5 I double-walled reaction vessel containing a thermometer.

stirrer, reflux condenser and two entries for separate feeds. 4.56 g (0.02 mol)
of dibutyl maleate were stirred into the melt and subsequently 2000 g of tap
water were added, a strongly alkaline aqueous solution of the vinyl ether being
obtained.
Subsequently, 310 mg of FeSO4 7H2O, 1.99 g of 3-mercaptopropionic acid
and 12.00 g of 50% strength aqueous hydrogen peroxide were added.
Subsequently, 144.12 g (2.00 mol) of acrylic acid were mixed at room
temperature with 350 g of tap water, an additional regulator amount of 4.31 g
of 3-mercaptopropionic acid being contained. This was added to the receiver
mixture over a period of 85 minutes. Separately to this, the metering of 78 ml
of a 2% strength aqueous solution of Bruggolit™ took place over a period of
97 minutes, the temperature rising to a maximum of 31.1 °C.
After addition was complete, the mixture was stirred for a further 10 minutes
and adjusted to a pH of 6.50 by addition of aqueous sodium hydroxide
solution. The weight average molecular weight of the copolymer was 33300
g/mol.
Example 5
2000 g (1.00 mol) of propenyloxypolyethylene glycol 2000 of the general
formula (II) (average molecular weight 2000 g/mol) were introduced as a melt
at 85°C into a 51 double-walled reaction vessel containing a thermometer,
stirrer, reflux condenser and two entries for separate feeds.
Subsequently, 2000 g of tap water were added, a strongly alkaline aqueous
solution of the vinyl ether being obtained. 58.80 g (0.60 mol) of maleic
anhydride dissolved in 137.2 g of water (corresponding to a 30% strength
solution) and separately 10.86 g of 20% strength aqueous sodium hydroxide
solution were added with stirring and cooling, the temperature being kept
below 30°C.
Subsequently, 36.00 g (0.02 mol) of a reaction product of a butanol-started
monofunctional NH2-terminated ethylene oxide/propylene oxide block polymer
(EO 4, PO 27; molecular weight 1800 g) with maleic anhydride were added
with short-term intensive stirring. Subsequently, 380 mg of FeSO4 7H2O,

2.33 g of 3-mercaptopropionic acid and 13.50 g of 50% strength aqueous
hydrogen peroxide were added. Subsequently, 128.27 g (1.78 mol) of acrylic
acid dissolved in 350 g of tap water comprising an additional regulator amount
of 6.31 g of 3-mercaptopropionic acid were added to the receiver mixture at
room temperature over a period of 85 minutes. Separately to this, the metering
of 91 ml of a 2% strength aqueous solution of Brtiggolit™took place over a
period of 97 minutes, the temperature rising to a maximum of 30.9°C.
After addition was complete, the mixture was stirred for a further 10 minutes
and adjusted to a pH of 6.50 by addition of aqueous sodium hydroxide
solution. The weight average molecular weight of the copolymer was 31200
g/mol.
Comparative examples
Comparative example 1
The procedure was as described in Example 1, but instead of the
propenyloxypolyethylene glycol of the general formula (II) used there a
vinyloxybutylpoly(ethylene glycol) having the average molecular weight
500 g/mol was used. Otherwise, the same required amounts as in Example 1
were used.
Comparative example 2
The procedure was as described in Example 5, but instead of the
propenyloxypolyethylene glycol (MW = 2000) of the general formula (II) used
there a vinyloxybutylpoly(ethylene glycol) having the average molecular
weight 2000 g/mol was used.

Use examples
Use example 1
(Ready-mixed concrete)
As standard, 4.5 kg of Portland cement (CEM 142.5 R Bernburg) were mixed
with 33 kg of aggregates (grading curve 0 to 32 mm) and 2.7 kg of water
including the water from the additive in a concrete mechanical mixer. The
aqueous solutions of the additives were added and 10 minutes and 40 minutes
after the beginning of the test the determination of the degree of spread was
carried out according to DIN EN 12350-5.
Test bodies of edge length 15x15x15 cm were subsequently prepared and
the compressive strength after 24 hours and the air pore content were
determined (by means of density of the hardened sample).
�

Use example 2
(Finished part concrete)
Finished part formulation as described above, but 5.75 kg of Portland cement
CEM I 52.5 R Bernburg, 2.3 kg of water and 33 kg of aggregate.

WE CLAIM:
1. Copolymers based on unsaturated mono- or dicarboxylic acid derivatives and oxyalkylene
glycol alkenyl ethers, comprising
a) 10 to 90 mol% of the structural groups of at least one of the formulae (la) and (lb)

where
R1 = hydrogen or an aliphatic hydrocarbon radical having 1 to 20 C atoms
X = H, -COOMa, -CO-O(CmH2mO) n-R2, -CO-NH-(CmH2mO)n-R2
M = hydrogen, a mono- or divalent metal cation, ammonium ion, an
organic amine radical
a = ½ or 1
R2 = hydrogen, an aliphatic hydrocarbon radical having 1 to 20 C atoms, a cycloaliphatic
hydrocarbon radical having 5 to 8 C atoms, an optionally substituted aryl radical
having 6 to 14 C atoms

Y = O, NR2
m =2 to 4 and
N = 0 to 200,
b) 1 to 89 mol% of structural groups of the general formula (II)

where
R3 = H, an aliphatic hydrocarbon radical having 1 to 6 C atoms
R4 = an aliphatic hydrocarbon radical having 1 to 6 C atoms, a cycloaliphatic hydrocarbon
radical having 1 to 6 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C
atoms and phenyl
R5 = H, an aliphatic hydrocarbon radical having 1 to 5 C atoms
R6, R7 = independently from each other H, an aliphatic hydrocarbon radical having 1 to 6
C atoms
P =0
q + r = 0 to 500
and

R2 has the abovementioned meaning
c) 0 to 10 mol% of structural groups of at least one of the formulae (IlIa) and (lllb)

where
Q = -H, -COOMa, -COOR9
T =U1-(CH-CH2-O)x-(CH-CH2-O)y-R10/

-(CH2-V-(CH2)z-CH=CH-R2, -COOR9 if Q= -COOR9 or COOMa
U1-CO-NH-Oo-CH2O-
U2 = -NH-CO-,-O-,-OCH2-
V = -O-CO-C6H4-CO-O-
M = hydrogen, a mono- or divalent metal cation, ammonium ion, an organic amine radical
R8= H,CH3

R9= an aliphatic hydrocarbon radical having 3 to 20 C atoms, a cycloaliphatic
hydrocarbon radical having 5 to 8 C atoms, an aryl radical having 6 to 14 C atoms
R10= R2, -CH2-CH-U2-C=CH
I I I
R8 R8Q
z =0 to 4
x = 1 to 150
y =0 to 15, and
R2, R6 and R7 have the abovementioned meaning.
2. Copolymers as claimed in claim 1, wherein they additionally contain
d) 0-50 mol% of structural groups (IV), the monomers of which represent a vinyl- or
(meth) acrylic acid derivative.
3. Copolymers as claimed in claim 1, wherein R1 = hydrogen or a methyl radical.
4. Copolymers as claimed in claims 1 and 3, wherein M is a mono- or divalent metal cation
selected from the group consisting of sodium, potassium, calcium or magnesium ions.
5. Copolymers as claimed in claims 1 to 4, wherein if R2 = phenyl the phenyl radical is

additionally substituted by hydroxyl, carboxyl or sulphonic acid groups.

6. Copolymers as claimed in claims 1 to 5, wherein the formula (II) p = 0.
7. Copolymers as claimed in claims 1 to 6, wherein they contain 40 to 75 mol% of
structural groups of the formulae (la) at least of (lb), 20 to 55 mol% of structural groups
of the formula (II), 1 to 5 mol% of structural groups of the formulae (Ilia) at least of (Nib).
8. Copolymers as claimed in claims 1 to 7, wherein they additionally contain up to 50 mol%,
in particular up to 20 mol%, based on the sum of the structural groups of the formulae
(I), (II) and (III), of structural groups whose monomers are a vinyl- or (meth) acrylic acid
derivative.
9. Copolymers as claimed in claims 2 and 8, wherein the monomeric vinyl derivative used
was styrene, α-methylstyrene, vinyl acetate, vinyl propionate, ethylene, propylene,
isobutene, N-vinylpyrrolidone, allylsulphonic acid, methallylsulphonic acid,
vinylsulphonic acid or vinylphosphonic acid.
10. Copolymers as claimed in claims 2 and 8, wherein the monomeric (meth) acrylic acid
derivative employed was hydroxyalkyl (meth) acrylamide, methacrylamide, AMPS,
methyl methacrylate, methyl acrylate, butyl acrylate or cyclohexyl acrylate.
11. Copolymers as claimed in claims 1 to 10, wherein they have an average molecular weight
of 5000 to 100000 g/mol.

12. Process for the preparation of the copolymers as claimed in claims 1 to 11, wherein 10 to
90 mol% of an unsaturated mono- or dicarboxylic acid derivative, 1 to 89 mol% of an
oxyalkylene glycol alkenyl ether, 0 to 10 mol% of a vinylic polyalkylene glycol or ester
compound are polymerized with the aid of a free-radical starter.
13. Process as claimed in claim 12, wherein 40 to 75 mol% of an unsaturated mono- or
dicarboxylic acid derivative, 20 to 55 mol% of an oxyalkylene glycol alkenyl ether and 1
to 5 mol% of a vinylic polyalkylene glycol or ester compound are employed.
14. Process as claimed in claims 12 and 13, wherein additionally up to 50 mol%, in particular
up to 20 mol%, based on the monomers having the structural groups as in the
formulae(l), (II), (III) and (IV), of a vinyl or (meth) acrylic acid derivative are
copolymerized.

15. Process as claimed in claims 12 and 13, wherein the polymerization is carried out in
aqueous solution at a temperature of 20 to 100°C.
16. Process as claimed in claim 15, wherein the concentration of the aqueous solution is 30 to
50% by weight.
17. Process as claimed in claims 12 to 14, wherein the polymerization is carried out without
solvent with the aid of a free-radical starter at temperatures of 20 to 150°C.

18. Copolymers as claimed in claims 1 to 11 as an additive for aqueous suspensions based on
mineral or bituminous binders, in particular cement, gypsum, lime, anhydrite, or other
calcium sulphate based binders and based on pulverulent dispersion binders.
19. Copolymers as claimed in claim 18 wherein they are employed in an amount from 0.01 to
10% by weight, preferably 0.1 to 5 % by weight, based on the weight of the mineral
binder.

ABSTRACT

COPOLYMERS BASED ON UNSATURATED MONO-OR ICARBOXYLIC
ACID DERIVATIVES AND OXYALKYLENE GLYCOL ALKENYL THERS,
PROCESSES FOR THEIR PREPARATION
Copolymers based on unsaturated mono-or dicarboxylic acid derivatives,
oxyalkylene glycol alkenyl ethers and optionally vinylic polyalkylene glycol
or ester compounds are described and also their use as additives for
aqueous suspensions based on mineral or bituminous binders, in particular
cement, gypsum, lime, anhydrite, or other calcium sulphate-based binders,
and based on pulverulent dispersion binders. The copolymers according to
the invention impart to the aqueous binder suspensions a very good
dispersing and liquefying action with, at the same time, simultaneous
excellent processing properties. Moreover, the oxyalkylene glycol alkenyl
ether according to the invention are industrially relatively simple and
inexpensive to prepare and need comparatively low initiator concentrations
in the copolymerization.

COPOLYMERS BASED ON UNSATURATED MONO-OR DICARBOXYLIC ACID DERIVATIVES AND OXYALKYLENE GLYCOL ALKENYL ETHERS, PROCESSES FOR THEIR PREPARATION

Documents:

Inventors:

PCT Conventions: