Title of Invention	A METHOD OF PRODUCING A COMPOSITE METAL HYDROXIDE.
Abstract	TITLE: A METHOD OF PRODUCING A COMPOSITE METAL HYDROXIDE. THIS INVENTION RELATES TO A METHOD OF PRODUCING A COMPOSITE METAL HYDROXIDE COMPRISING THE STEPS OF HEATING THE COMPOSITE METAL HYDROXIDE IN THE PRESENCE OF REACTION MOTHER LIQUOR AT A TEMPERATURE WITHIN A RANGE OF 80 TO 150 DEGREE C AND SUBSTITUTING NI FOR AT LEAST ONE OF MG AND ZN ON THE CRYSTAL SURFACE THEREOF, BY ADDING A SOLUTION OF A WATER-SOLUBLE NICKEL COMPOUND SUCH AS AQUEOUS SOLUTIONS OF NICKEL CHLORIDE, NICKEL NITRATE AND THE LIKE.

Title of Invention

A METHOD OF PRODUCING A COMPOSITE METAL HYDROXIDE.

Abstract

TITLE: A METHOD OF PRODUCING A COMPOSITE METAL HYDROXIDE. THIS INVENTION RELATES TO A METHOD OF PRODUCING A COMPOSITE METAL HYDROXIDE COMPRISING THE STEPS OF HEATING THE COMPOSITE METAL HYDROXIDE IN THE PRESENCE OF REACTION MOTHER LIQUOR AT A TEMPERATURE WITHIN A RANGE OF 80 TO 150 DEGREE C AND SUBSTITUTING NI FOR AT LEAST ONE OF MG AND ZN ON THE CRYSTAL SURFACE THEREOF, BY ADDING A SOLUTION OF A WATER-SOLUBLE NICKEL COMPOUND SUCH AS AQUEOUS SOLUTIONS OF NICKEL CHLORIDE, NICKEL NITRATE AND THE LIKE.

Full Text	FIELD OF THE INVENTION: The present invention relates to a method of producing a composite metal hydroxide of a uniform solid solution, a composite metal hydroxide obtained thereby and a flame retardant high-molecular composition thereby and therewith superior in flame retardancy and mechanical strength. This application has been divided out of the parent application no. 1382/Cal/96 of 2.8.96 which relates to "A method of producing a composite metal hydroxide". BACKGROUND OF THE INVENTION: A demand for flame retardancy on resin composition or rubber composition has been increased year by year since a critical conflagration occurred in the past, To respond to such a strong demand for Improving flame retardancy, various flame retardants are marketed at present. Among all, in view of safety in manufacturing or using, a demand for improving flame retardancy has severely been increased centered on non-haloganated flame retardants. Under such a situation, metal hydroxides have come to be focused upon. However, since a dehydration temperature of, for example, aluminium hydroxide is iow (about 190°C) among the above metal hydroxides, there is a drawback that the kinds of applicable resins are limited in order to retain a molding temperature beiow the temperature of dehydration. In the meantime, since an Initial dehydration temperature for magnesium hydroxide is about 340°C, there is almost no limitation of the kinds of resins, however, a large amount should be added to obtain flame refardancy, resulting in deterioration of physical properties inherent in resins. Namely, there have been many problems practically. To solve these problems, for example, a composite metal hydroxide is proposed in Japanese Patent Provisional Publication (Tokkaihei) 6-41441. Compared with a magnesium hydroxide, the composite metal hydroxide realizes flame retardancy with less amount. However, when using zinc and magnesium hydroxide for producing a composite metal hydroxide, basic salts and oxides (zinc oxides) may be caused as by-products by characteristics of zinc as a solid solution element in a conventional method. In this way, It is difficult to obtain a composite metal hydroxide of a uniform solid solution and realize expected properties thereof such as flame retardancy and mechanical strength. Accordingly, it is an object of the present invention to provide a method of producing a composite metal hydroxide of a uniform solid solution having excellent flame retardancy, a composite metal hydroxide obtained thereby and a flame retardant high-molecular composition superior In mechanical strength obtained thereby and therewith. To accomplish the above object, a first gist of the invention relates to a method of producing a composite metal hydroxide characterized by reacting magnesium-containing aqueous solution (X) including water soluble zinc compound wherein magnesium ion concentration is 0.01 to 1 mol/liter with alkaline material (Y) at a reaction equivalent ratio (X:Y) of X:Y˜ 1:1.01 to 1:1.20. A second gist of the invention relates to a method of producing a composite metal hydroxide thereby wherein the produced composite metal hydroxide is hydrot her malty treated at a temperature within a range of 100 to 2G0°C in chlorine-containing aqueous medium wherein chlorine ion concentration is 0.5 to 2.0 mol/liter. A third gist of ths invention relates to a method of producing a composite metal hydroxide thereby wherein the produced metai hydroxide is heated in the presence of reaction mother liquor at a temperature within a range of 30 to 150°C and only the crystal surface thereof is substituted for nickel by adding water soluble nickel compound solution. A forth gist of the invention relates to a composite metal hydroxide obtained by a method according to the above first or second gist represented by the following general formula (1); Mg1-xZnx(OH)2 .....(1) wherein x indicates a positive number within a range of 0.003 = x = 0.1. A Fifth gist of the invention relates to a composite metal hydroxide obtained by a method according to the third gist represented by the following general formula (2); Mg1.x.yZnxNiy(OH)2..................(2) wherein x indicates a positive number within a range of 0.003= X = 0.1 and y indicates a positive number within a range of 0.01iy = 0.05 A sixth gist of the invention relates to a flame retardant high- molecular composition containing a composite metal hydroxide represented by the general formula (1) or (2) within a range of 80 to 150 parts by weight based on 100 parts by weight of the high-molecular composition. It is difficult to stably produce a composite metal hydroxide of a uniform solid solution with Mg in conventional methods, since a stable crystal shape for a hydroxide is not hexagonal. For this reason, the inventors of the present invention have piled up studies on reaction processes for obtaining a uniform solid solution. Focused upon two points, the inventors have further accumulated their studies; one is an Mg ion concentration of Zn-containing Mg aqueous solution as a source of Mg and the other is a reaction equivalent ratio of the Zn-ccntaining Mg aqueous solution and alkaline material. As a result, they reached a conclusion that a composite metal hydroxide of a uniform solid solution represented by the above general formula (1) can be obtained by using Zn-containing Mg aqueous solution wherein Mg ion concentration Is set within a range of 0.01 to 1.0 mol/Jrter and reacting the Zn-containing Mg aqueous solution (x) and the alkaline material (Y) at a reaction equivalent ratio of (X:Y)=1:1.01 to 1:1.20. Further, they found out that occurrence of secondary aggregation can be restrained because the crystal shape of the composite metal hydroxide can be controlled by hydrothermally treatlng the composite metal hydroxide obtained by reacting thereof at the above reaction equivalent ratio in an aqueous medium having a specific chlorine ion concentration within a temperature range of 100 to 200°C for aging. Still further, they reached the present invention that the composite metal hydroxide represented by the general formula (2) wherein only the crystal surface is substituted for Ni can be obtained by heating thus obtained composite metal hydroxide within a temperature range of 80 to 150°C in the presence of reaction mother liquor and adding water soluble Ni compound solution therein. Even still further, they found out that the flame retardant high- molecular composition wherein the composite metal hydroxide represented by the general formula (1) or (2) is contained within a range of 80 to 150 parts by weight (just abbreviated to parts hereinafter) based on 100 parts of the high-molecular compound has superior flame retardancy and satisfactory mechanical strength (such as tensile strength) even with less content thereof compared with the conventional ones. DISCLOSURE OF THE INVENTION: Now, the present invention is described in detail. The method for producing the composite metal hydroxide of the present invention comprises three steps roughly. That is, the first step is a reaction step for producing the composite metal hydroxide represented by the following general formula (1) by reacting Zn-contalnlng Mg aqueous solution having a specific Mg Ion concentration and alkaline material at a specific equivalent ratio. This first reaction step is preferable conducted within a temperature range of 10 to 35°C. Mg1-xZnx(OH)2 .... (1) wherein x represents a positive number within a range of 0.003=x=0.1 In the general formula (1), x value less than 0.003 is solid solution amount insufficient for emerging the expected effect of the composite metai hydroxide (superior flame retardancy). in the meantime, x value over 0.1 results in difficulty In forming a uniform solid solution, causing basic salts and oxides as by product, since an ion radius of zinc is larger than that of magnesium. Further, it is difficult to control a crystal shape and easy to cause secondary aggregation, which does not bring about the expected effect of the composite metal hydroxide. As the Zn-containing Mg aqueous solution, such an aqueous solution that Zn compound Is added into Mg aqueous solution is enumerated. As a source of the Mg aqueous solution, diluted bittern, sea water, magnesium nitrate and the like are enumerated in which Mg ion concentration should be set within a range of 0.01 to 1 mo (/lifer. Preferably it is within a range of 0.03 to 0.3 mol/liter, Namely, for example, when diluted bittern or sea water is adopted, Mg ion concentration over 1 mol/ltter overwhelmingly causes by-products of basic salts, resulting in difficulty in forming a uniform solid solution. In addition, the Mg Ion concentration may be measured by a chela to metric titration method, an ICP emission spectrochemical analysis and the like. Measurement Is, however, not critical as long as It is a method for analyzing ion concentration in aqueous solution generally. As the Zn compound to be added into the Mg aqueous solution,any wafer soluble zinc compound such as zinc nitrate or zinc chloride is included with no limitation. The addition amount thereof based on the Mg aqueous solution is preferably set within a range of 0.3 to 10 mol% based on the Mg in the aqueous solution, more preferably 1 to 7 mol%. Namely the addition amount less than 0.3 mol % is too small an amount of solid solution to emerge the expected effect of a composite metal hydroxide. On the other hand, that over 10 mol % results in difficulty In forming a uniform solid solution since a zinc ion radius is larger than that of magnesium, causing basic salts and oxides as by-products. Further, it is difficult to control a crystal shape and easy to cause secondary aggregation, which shows a tendency that the expected effect of the composite metal hydroxide cannot be emerged. Still further, as the alkaline material to be reacted with the Zn- containlng Mg aqueous solution having a specific Mg Ion concentration, calcium hydroxide, sodium hydroxide and the like are enumerated. Furthermore, the reaction ratio of the Zn-containing Mg aqueous solution (X) and the alkaline material (Y) at the first step is needed to be set at the equivalent ratio (X:Y)=1:1.01 to 1:1.20. Preferably, it Is set at X:Y=1:1.03 to 1:1.10. Namely, when the alkaline material (Y) is less than 1.01 or the reaction equivalent ratio, by-products of basic salts may be identified, preventing formation of a uniform solid solution thereby, while when it is over 1.20, by-products of oxides may be identified, causing difficulty in controlling a crystal shape resulting in easiness in occurrence of secondary aggregation. The preferable combination of the Zn-containing Mg aqueous solution and the alkaline material at the first step is to adopt sea water (Mg aqueous solution) wherein zinc chloride, water soluble zinc compound,is added into Zn-containing Mg aqueous solution and calcium hydroxide (limemilk) as an alkaline material in view of stability of the produced composite metal hydroxide and the manufacturing cost. Subsequently, a method of the second step following the method of producing the composite metal hydroxide as the above first step is described here. The second step comprises thermally treating the composite metal hydroxide represented by the general formula (1) produced in the first step in chlorine-containing aqueous medium with a specific chlorine ion concentration within a temperature range of 100 to 2000C to be aged. As the chlorine-containing aqueous medium, aqueous solutions of calcium chloride, sodium chloride, magnesium chloride, potassium chloride and the like are enumerated. Among all, it is preferably to adopt calcium chloride aqueous solution as the chlorine-containing aqueous medium in view of controllability of the crystal shape of the composite metal hydroxide. Further, the chlorine ion concentration in the chlorine- containing aqueous medium should be set within a range of 0.5 to 2 mol/liter. Preferably, it is within a range of 0.5 to 1.0 mol/llter. Namely, low concentration of chlorine ion less than 0.5 mol/liter may cause insufficient controllability of a crystal shape of the composite metal hydroxide, resulting in the easiness in occurrence of secondary aggregation. On the other hand, that over 2 mol/Wer may cause basic salts and oxides as by- products, resulting in difficulty in forming a uniform solid solution. In addition, the chlorine ion concentration may be measured by a general method for analyzing ion concentration in solution, such as a chelatometrlc tltration method or an ICP emission spectrochemical analysis. Even further, as the aging conditions for the thermal treatment, the temperature should be set within a range of 100 to 200°C and the pressure should be within a range of 0.5 to 10 kg/cm2 concomttantiy. Thus obtained composite metal hydroxide is represented by the general formula (1). The crystals may further grow and secondary aggregation may decrease through the second step, which results in more preferable flame retardants in view of various properties such as compatibility with a high-molecular compound, disperisibility, appearance of the formed product or mechanical strength. Next, the third step following the method of producing the composite metal hydroxide as the second step is described. The composite metal hydroxide obtained by this step is such as represented by the general formula (2), a solid solution comprising three metals of Mg, Zn, and Ni. Mg1-x-yZnxNly(OH)2.................(2) wherein x represents a positive number within a range of 0.003=y=0.1 and y represents a positive number within a range of 0.01=y=0.05. In the general formula (2), x value less than 0.003 is too small an amount of solid solution to emerge the expected effect (superior flame relardancy) of a composite metal hydroxide. On the other hand, that over 0.1 mol % results in difficulty in forming a uniform solid solution since an Ion diameter of zinc is larger than that of magnesium, causing by-products of basic salts and oxides. In addition, it may cause difficulty in controlling a crystal shape and easiness in occurrence of secondary aggregation, which does not bring about the expected effect of composite metal hydroxide. In the meantime, y value less than 0.01 may cause insufficiency of nickel substitution amount on the crystal surface, which does not fully emerge the expected effect of the composite metal hydroxide, in addition, that over 0.05 may cause cost increase and also saturation of the nickel substitution amount on the crystal surface, resulting in by-products of free nickel hydroxide and the like. In the third step, the composite metal hydroxide represented by the general formula (1), which was produced in the second step, is heated in the presence of reaction mother liquor within a temperature range of 80 to 150°C and water soluble nickel compound solution is added therein so as to substitute only the crystal surface for Nl, resulting In the composite metal hydroxide represented by the general formula (2). As the water soluble nickel composite solution, aqueous solutions of nickel chloride, nickel nitrate and the like are enumerated. Among all, It is preferable to use nickel chloride in view of reactivity with composite metal hydroxide. Further the mixing ratio of such water soluble nickel compound solution is preferably set within 1 to 5 moi % based on the composite metal hydroxide of a reaction mother liquor. Particularly, it is preferable to be within 1 to 3 moi %. In the meantime, a heating condition in adding water soluble nickel compound solution, as mentioned above, is set within a temperature range of 80 to 150°C. Particularly, it is preferable to set within a temperature range of 90 to 120°C. By setting as such, It becomes possible to substitute only the crystal surface effectively for nickel. Namely the lower temperature may cause free nickel hydroxides as by-products due to insufficient substitution. On the other hand, the higher temperature may cause excessive nickel substitution extending into the inside of crystal structure. In both ways, the expected effect is not realized. Thus, as the composite metal hydroxide represented by the general formula (1) through the first or second step, or represented by the general formula (2) through the third step, the crystal size is 0.2 to 4 mm, more preferably 0.2 to 2pm, most preferably 0.5 to 1.5 mm, and that with almost no or less secondary aggregation, which means that the average secondary particle size is 0.2 to 4mm, more preferably 0.2 to 2 mm, most preferably 0.5 to 1.5pm, and also a BET specific surface area is 1 to 20 mVg, preferably 3 to 15 m2/g, most preferably 6 to 12 m2/g. Namely, since each value for the composite metal hydroxide is set within a range as above, it becomes possible to retain superior effects in compatibility with high-molecular com pounds such as resin or rubber, dispersibility, forming capability, appearance of the formed products, mechanical strength and the Wee to be mentioned below. In addition, the above average secondary particle diameter is a value measured by the microtrack method on sample powder, which was dispersed by as ultrasonic treatment, in 0.2% sodium hexametaphosphate aqueous solution. The BET specific surface area is a value in accordance with an N2 adsorption method. Thus obtained composite metal hydroxide represented by the above general formula (1) or (2), may be used as a flame retardant as it is, however, it may possible to additionally conduct surface treatment with finishing agents such as various fatty acids, phosphoric acid ester, coupling agents and the like. The various finishing agents may be used solely or in combination of two or more. As the various fatty acids, higher fatty acids having 10 or more carbon atoms such as stearic acid, oielc acid, erucic add, palmitic acid, lauric acid and behenic acid, and alkall metal salts thereof may be listed, in addition, as the phosphate esters, mono-or diesters of orthophosphoric acid with oleyi alcohol or stearyl alcohol, mixtures of these, acid type or alkali metal salts or amine salts thereof may be listed. As the above couplings agents, silane-coupling agents such as vinylethoxysilane, vinyl-tris(2-methoxy-ethoxy)silane methacryloxypropyltrimethoxysllane, grycidioxypropyltrimethoxysilane, aminopropyitrimethoxysiiane epoxycyclohexyl)ethyltrimethoxysilane, mercaptopropyftrlmethoxysllane, tltanate coupling agents such as isopropyltrisostearoyl titanate, isopropyitris (dioctylpyrophosphate)titanate, isopropyltrl(N-aminoethyl-aminoethyl) titanate and isopropyitridecyibenzenesulfonyi titanate; aluminium coupling agents such as acetoalkoxyalminium diisopropylate. As the above surface treatment with various finishing agents, a conventional moisture or dry method is available, with no limitation. Then, by adding the composite metal hydroxide represented by the general formula (1) or (2) as a flame retardant into the high -molecular compound, a flame retardant having high-molecular composition can be obtained. As the above high-molecular compound, general resin, rubber and the like may be emumerated. For example, a copolymer of polyethylene or ethylene with other a-olefin, a copolymer of ethylene with vinyl acetate, ethyl acrylate or methyl acrylate, polypropylene, a copolymer of propylene with other a-olefin, polybutene-l, polystyrene, a styrene-acrylonltrile copolymer, thermoplastic resin such as vinyl acetate, poryacrylate, polymerchacrylate, polyurethane, polyester, polyether, pofyajmide, thermosetting resins such as phenolic resin, melamine resin, epoxy resin, unsaturated polyester resin, alkyd resin, ethylene-propylene-diene rubber, stylene-butadine rubber, acrylonitrile-butadiene rubber, butyl rubber, isoprene rubber, chlorosutfonated polyethlene and the like. These high- moiecuiar compounds are appropreatefy selected. At that time, the mixing ratio of the composite metal hydroxide represented by the general formula (1) or (2) is selected appropreately depending on the kinds of the above high-molecular compounds and the like, it is set within a range of 80 to 150 parts by weight based on 100 parts of the high-molecular compounds. Particularly, it is preferably 100 to 130 parts. Namely, the mixing ratio thereof less than 80 parts may cause insufficient flame retardancy, while that over 150 parts may cause deterioration in mechanical strength such as tensile strength. Further, the composite metal hydroxide represented by the general formula (1) or (2) may be used solely or In combination as long as its mixing ratio is set within the above range. Further, various additives may be added appropriately other than the above composite metal hydroxide represented by the general formula (I) or (2) into the flame retardant high-molecular composition of the present invention. For Example, a general flame retardant aid such as carbon fine powder, red phosphorus is enumerated. Moreover, lubricants, antioxidants, ultraviolet inhibitors, antistatic agents, pigments, foaming agents, plasticizers, fillers, reinforcing materials, crosslinking agents and the like are enumerated. The flame retardant high-molecular compound can be obtained by adding the composite metal hydroxide represented by the general formula (1) or (2) into the high-molecular compound at a specific ratio, mixing and then kneading thereof. As a method for mixing and kneading thereof, conventional methods such as single-screw or twin-screw extruder, a roll, Banbury mixer and the like may be enumerated with no limitation. Then, as a method for forming with thus obtained flame retardant high-molecular compound, a suitable molding method is selected appropriately depending on the kinds of the high-molecular compounds, the kinds of desired molded products and the like with no limitation. For Example, Injection molding, extrusion blow molding, press molding, rotational molding, calendering, sheet forming, transfer molding, laminate molding, vacuum molding and the like may be enumerated. Further, a solid solution containing Zn and Mg cannot be obtained by the methods disclosed by EP 9230773.6 (hereinafter Just referred as D1) and EP 92310744.5 (hereinafter just referred as D2). Only Zn is an amphoteric metal among Mn, Fe, Co, Nl, Cu and Zn, which are disclosed as divalent metals in D1 and D2, and Zn hydroxide in substantially unstable. Therefore, if reaction conditions such as reaction solution pH and mother liquor concentration are not maintained appropriately in producing a solid solution containing Zn and Mg by reacting aqueous solution thereof, basic salts and oxides may be caused as by-products, resulting in a difficulty in producing a uniform Zn solid solution. A reaction equivalent ratio of 0.5 to 0.95 disclosed in D1 and D2 is within such a range as causes basic salts. On the contrary, to solve the above problems, reaction solution pH is within an appropriate range of an alkaline side by adjusting a reaction equivalent ratio within 1.01 to 1.20, and by-production of basic salts is restrained by lowering mother liquor concentration, resulting in a uniform Zn solid solution. Namely, among products disclosed in D1 and 02, the products containing Zn as a divalent metal is not a uniform solution of Zn and Mg, but a mixture of magnesium hydroxide and basic zinc chloride. Therefore, it Is obvious that the product of the present Invention differs from those of 01 and D2, and flame retardancy cannot be realised from magnesium hydroxide solid solutions of D1 and D2. This is described in the following Examples 11 to 15 and Comparative Examples 8 to 10. Further, the crystal of the composite metal hydroxide of EP 92304925.8 (hereinafter just referred as D3) is long and fibrous, and has a length/diameter ratio of about 10 or more, an average diameter of approximately 0.1 to 10 urn and an average length of approximately 2 to 1000 urn. On the contrary, the crystal of the composite metal hydroxide of the present invention Is a hexagonal plate, and has an average diameter of 0.2 to 4 urn, an average thickness of 0 1 to 0.5 urn, and an aspect ratio (diameter/thickness ratio) of not more than 10. Further, the method of the present invention differs from that of D3. The method of D3 comprises the steps of adding an aqueous solution of the divalent transition metal of the formula M2+ A- 2 wherein M is a divalent metal such as Mn into an aqueous solution of magnesium salt represented by the formula MgA2 containing the acicular-crystal magnesium salt represented by the formula Mg(OH)2-y A-y • mH2O wherein A" is a monovalent anion with stirring, for obtaining the acicular- crystal basic magnesium salt represented by the formula M2+ x Mg1-x (OH)2-zA-z. mH2O, dehydrating thus obtained acicular-crystal basic magnesium salt, washing thereof with water, and then contacting the acicular-crystal basic magnesium salt with alkali such as sodium hydroxide In liquid medium such as water for reaction so as to substitute A z with OH " thus, the fibrous composite metal hydroxide can be obtained. On the contrary, a method of producing a composite metal hydroxide of the present invention comprises the steps of reacting magnesium-containing aqueous solution (X) including water soluble zinc compound wherein magnesium Ion concentration is 0.01 to 1 mol/llter with alkaline material (Y) at a reaction equivalent ratio (X;Y) of X;Y=1 1 01 to 1:1.20. EXAMPLE 1 By dissolving zinc chloride, a reagent of the first grade, into ionic bittern and diluting thereof with deiontzed water. 300-liter mixture aqueous solution with 0.14 mot/liter Mg ion concentration and 0.008 mo I/liter Zn ion concentration was produced. In the meantime, as the alkaline material , 51-liter limemilk with 0.9 mot/liter was produced. Both of them were mixed in such as manner that the reaction equivalent ratio is mixture aqueous solution;(imemilk=1;1.03 by charging thereof consecutively with stirring into a continuous reaction vessel of 50-liter effective volume. Then, this reactant was emulsified into calcium chloride aqueous solution with 1.0 mol/liter chlorine ion concentration, and thermally treated at 150°C for two hours by putting thereof into an autoclave of 100-liter effective volume with a stirrer. Thereafter, it was filtrated by a filter press, washed with water, dehydrated, dried in an oven and then pulverized, thus producing the composite metal hydroxide as an objective. EXAMPLE 2 Em unification of the reactant in example 1 was conducted in sodium chloride aqueous solution with 0.5 mol/liter chlorine ion concentration and the thermal treatmeftt was conducted at 170°C for two hours. Except for that, example 2 was the same as example 1, thus producing the composite metal hydroxide as an objective. EXAMPLE 3 By dissolving zinc nitrate, a reagent of the first grade, into ionic bittern and diluting thereof with deionized water, 50-liter mixture aqueous solution with 1.0 mol/liter Mg ion concentration and 0.003 mol/liter Zn ion concentration was produced. In the meantime, as the alkaline material, 52-liter lime milk with 1.0 mol/liter was produced. Both of them were mixed in such a manner that the reaction equivalent ratio is mixture aqueous solutlon:limemilk=1:1.04 by charging thereof consecutively with stirring into a continuous reaction vessel of 10-liter effective volume. Then, this reactant was emulsified into sodium chloride aqueous solution with 2.0 mol/liter chlorine ion concentration, and thermally treated at 150°C for two hours by putting thereof into an autoclave of 100-liter effective volume with a stirrer. Thereafter, it was filtrated by a fitter press, washed with water, dehydrated, dried in an over and the pulverized., thus producing the composite metal hydroxide as an objective. EXAMPLE 4 The reaction equivalent ratio of the mixture aqueous solution and iimemilk of example 3 was changed In such a manner that mixture aqueous solutlon.llmemllk=1.1,20. Except for that, example 4 was the same as example 3, thus producing the composite metal hydroxide as an objective. EXAMPLE 5 By dissolving magnesium nitrate and zinc nitrate, reagents of the first grade, Into delonized water, 1-llter mixture aqueous solution with 0.9 mot/liter Mg ion concentration and 0.1 mol/liter Zn ion concentration was produced, in the meantime, as the aikaiine material, 1-llter sodium hydroxide aqueous solution with 2.04 mol/ltter was produced. Both of them were mixed in such a manner that the reaction equivalent ratio is mixture aqueous solution : sodium hydroxide-1:1.02 by dropping the mixture aqueous solution into sodium hydroxide aqueous solution with stirring, thus producing reactant. This reactant was emulsified into sodium chloride aqueous solution with 1,0 mol/liter chlorine ion concentration, and thermally treated at 150r"C for two hours by putting thereof into an autoclave of 3-Ilter effective volume with a stirrer and thereafter, filtrated by a vacuum filter, washed with water, dehydrated, dried in an oven and then pulverized, thus obtaining the composite metal hydroxide as an objective. EXAMPLE 6 Synthetic sea water was produced by adding zinc nitrate into 1530-liter decarboxyiated sea water (Mg ion concentration: 0.032 mo (/liter) in such a manner that Zn ion concentration was 0.002 moi/iiter. In the meantime, as the alkaline material, 51-liter Hmemilfc with 1.07 mol/liter alkali ion concentration was produced. Then, both of them were mixed in such a manner that the reaction equivalent ratio is synthetic sea water:llmemllk=1:1.05 by charging (hereof consecutively with stirring into a continuous reaction vessel of 250-liter effective volume. Then, this reactant was emulsified into calcium chloride aqueous solution with 1.2 mol/liter chlorine ion concentration, and therm airy treated at 150°C for two hours by putting thereof into an autoclave of 100-liter effective volume with a stirrer. Thereafter, it was filtrated by a fitter press, washed with water, dehydrated, dried in an oven and then pulverized, thus producing the composite metal hydroxide as an objective. EXAMPLE 7 The reaction mother liquor after being thermally treated at 150°C for two hours In example 6 was cooled down to 100°C. And 3.5-liter nickel chloride aqueous solution with 0.3 mot/liter Ni ion concentration was added therein with stirring for aging with heating at 100°C for 30 minutes. Except for that, example 7 Is the same as example 6. EXAMPLE 8 The ratio of nickel chloride aqueous solution based on the produced composite metal hydroxide was changed to 1 mol % Except for that, example 8 was the same as example 7. EXAMPLE 9 The ratio of nickel chloride aqueous solution based on the produced composite metal hydroxide was changed to 5 moI % and the aging condition with heating was changed to 150°C for 30 minutes. Except for that, example 9 was the same as example 7. EXAMPLE 10 The reaction mother liquor after being thermally treated at 1S0°C for two hours in example 3 was cooled down to 100°C, And 3.9 liter nickel chloride aqueous solution with 0.4 mo I/liter Ni ion concentration was added therein with stirring for aging with heating at 100°C for 30 minutes. Except for that, example 10 is the same as example 6. COMPARATIVE EXAMPLE 1 By dissolving zinc chloride, a reagent of the first grade, into bittern, 30-liter mixture aqueous solution with 1.7 mol/liter Mg ion concentration and 0.085 mol/Irter Zn ion concentration was produced, In the meantime, as thB alkaline material, 46-liter lime milk with 1.0 mol/liter alkaline ion concentration was produced. There, both of them were charged into a continuous reaction vessel of 2.5 -liter effective volume with stirring for reaction in such a manner that mixture aqueous solution:limemilk=1:0.9 at a reaction equivalent ratio. Further, this reactant was put into an autoclave of 100-liter effective volume with a stirrer for thermal treatment at 150°C for two hours. Thereafter, It was nitrated by a niter press, washed with water, dehydrated, dried In an oven and then pulverized, thus producing the composite metai hydroxide as an objective. COMPARATIVE EXAMPLE 2 The reaction equivalent ratio of the mixture aqueous solution and the lime milk was changed to 1:1.05. Except for that, comparative example 2 was the same as comparative example 1 so as to obtain the resultant product. COMPARATIVE EXAMPLE 3 The reaction equivalent ratio of the mixture aqueous solution and the sodium hydroxide of example 5 was changed to 1:1.25. Except for that, comparative example 3 was the same as example 5 so as to produce the resultant product. COMPARATIVE EXAMPLE 4 The reaction equivalent ratio of the mixture aqueous solution and the sodium hydroxide of example 5 was changed to 1:1.00. Except for that, comparative example 4 was the same as example 5 so as to produce " the resultant produce. COMPARATIVE EXAMPLE 5 A mixture aqueous solution of 1.1 mol/liter Mg ion concentration and 0.055 mol/ltter Zn ion concentration was produced. In the meantime, the reaction equivalent ratio for the mixture aqueous solution and the lime milk was set at 1:1.05. Except for that, comparative example 5 was the same as comparative example 1. COMPARATIVE EXAMPLE 6 The mixture aqueous solution of example 1 was changed to that of 0.14 mol/liter Mg ion concentration and 0.019 mot/liter Zn ion concentration. Except for that, comparative example 6 was the same as example 1. COMPARATIVE EXAMPLE 7 The mixture aqueous solution of example 1 was changed to that of 0 88 mol/liter Mg ion concentration and 0.12 mot/liter Zn ion concentration. Except for that, comparative example 7 was the same as example 1. Each chemical composition, average secondary particle diameter and BET specific surface area of thus obtained various composite metal hydroxides was measured. The results are shown in the following tables 1 and 2. The chemical composition was quantitatively determined by an x- ray fluorescence analysis, and a cheiatometric titration method, an ICP emission spectrochemical analysis or the like on the mixture wherein a composite metal hydroxide was solved into hydrochloric acid for quantification of content by element, and also identified and measured on lattice constant by x-ray diffraction to judge whether a uniform solid solution was realized or not. The above average secondary particle size was measured by a microtrack method after conducting ultrasonic dispersion treatment on sample powder in 0.2% sodium hexametaphosphate aqueous solution. The BET specific surface area was measured by an N2 adsorption method. From the above tables 1 and 2, it is found out that a uniform solid solution was obtained in every example. EXAMPLES 11 TO 15 Next, each composite metal hydroxide (of examples) shown in the following table 3 was suspended into water respectively, heated up to 70°C with stirring. Subsequently, sodium oleate dissolved in advance was added into the composite metal hydroxide by 2 weight % as oleic acid so as to be surface treated. Then, it was dehydrated, washed with water and dried in an oven. Further, as a specimen, 0.2 parts antioxidant and each composite metal hydroxide (of examples), surface treated at ratios shown in the following table 3, were added based on 100 parts ethylene-ethylacrylate coporymer (ethylene acrylate content; 15 weight %, Nippon Petrochemicals Co. Ltd) so as to be mixed in a blender. After being mixed, it was kneaded by an open-roll mixer at 130°C and further press-molded at 160°C so as to be made into a sheet in 1 mm thickness and a sheet in about 3.2 mm thickness (1/8 inch) respectively. Then, each of the sheets was punched Into a dumbbell-shape and a strip-shape as samples respectively. These samples were subjected to a tensile test in accordance with JIS C3005 and a combustibility test in accordance with UL94VE. COMPARATIVE EXAMPLES B TO 11 Each reaction product (of comparative examples) and Mg(QHh shown In the following table 4 were mixed at ratios specified therein . Except for that, each sheet was formed in the same way as that of examples 12 to 19. Then, each sheet was punched into a dumbbell-shape and a stripe-shape as specimens. These specimens were subjected to a tensile test in accordance with JIS C300S and a combustibility test in accordance with UL94VE. The results of tensile strength and combustibility tests by using these specimens are shown in the following tables 5 and 6. From the above tables 5 and 6, it is found out that all comparative examples were low in tensile strength and inferior in mechanical strength. Further, good results were not obtained for flame retardancy on comparative examples 8 to 10. On the other hand, good results were obtained for flame retardancy on ail examples although composite metal hydroxides were less added than in comparative examples. Still further, tensile strength on examples was superior to that of ail comparative examples, which shows that all examples retain high flame retardancy as well as mechanical strength. EFFECTS OF THE INVENTION As the above, the composite metal hydroxide represented by the general formula (1) is produced by reacting Zn-confalning Mg aqueous solution having a specific Mg ion concentration and alkaline material at a specific reaction equivalent ratio. For this reason, a composite metal hydroxide, a uniform solid solution, wherein Zn is solid solved Into Mg system, which Is difficult to produce in the conventional methods can be obtained. Further, the composite metal hydroxide obtained at this reaction equivalent ratio is aged in aqueous medium having a specific chlorine ion concentration at a specific temperature so as to produce the composite metal hydroxide represented by general formu!a(1), whose crystal shape can be controlled, which prevents occurrence of secondary aggregation. in addition, the composite metal hydroxide represented by the general formula (2) wherein only the crystal surface is substituted for Ni can be obtained by adding water soluble Ni compound solution into the composite metal hydroxide represented by the general formula (1) at a specific temperature in the presence of reaction mother liquor. Thus obtained composite metal hydroxide is a uniform solid solution wherein Zn is solid solved into Mg system. Therefore, the flame retardant high-molecular composition obtained by mixing the composite metal hydroxide represented by the general formula (1) or (2) at a specific volume based on the high-molecular compound exerts high flame retardancy with less content thereof compared with the conventional ones and shows superiority in mechanical strength. WE CLAIM: 1. A method of producing a composite metal hydroxide of general formula Mg1-x-yZnxNIy(OH)2.........(2) comprising the steps of heating the composite metal hydroxide of general formula (1) Mg1-xZnx(OH)2.........(1) in the presence of reaction mother liquor at a temperature within a range of 80 to 150°C and substituting Nl for at least one of Mg and Zn on the crystal surface thereof, by adding a solution of a water-soluble nickel compound such as aqueous solutions of nickel chloride, nickel nitrate and the like. This invention relates to a method of producing a composite metal hydroxide comprising the steps of heating the composite metal hydroxide in the presence of reaction mother liquor at a temperature within a range of 80 to 150°C and substituting Ni for at least one of Mg and Zn on the crystal surface thereof, by adding a solution of a water-soluble nickel compound such as aqueous solutions of nickel chloride, nickel nitrate and the like.

Full Text

FIELD OF THE INVENTION:
The present invention relates to a method of producing a composite
metal hydroxide of a uniform solid solution, a composite metal hydroxide
obtained thereby and a flame retardant high-molecular composition
thereby and therewith superior in flame retardancy and mechanical
strength.
This application has been divided out of the parent application no.
1382/Cal/96 of 2.8.96 which relates to "A method of producing a
composite metal hydroxide".
BACKGROUND OF THE INVENTION:
A demand for flame retardancy on resin composition or rubber
composition has been increased year by year since a critical
conflagration occurred in the past,
To respond to such a strong demand for Improving flame
retardancy, various flame retardants are marketed at present. Among all,
in view of safety in manufacturing or using, a demand for improving flame
retardancy has severely been increased centered on non-haloganated
flame retardants. Under such a situation, metal hydroxides have come to
be focused upon.
However, since a dehydration temperature of, for example,
aluminium hydroxide is iow (about 190°C) among the above metal
hydroxides, there is a drawback that the kinds of applicable resins are
limited in order to retain a molding temperature beiow the temperature of
dehydration. In the meantime, since an Initial dehydration temperature for
magnesium hydroxide is about 340°C, there is almost no limitation of the

kinds of resins, however, a large amount should be added to obtain flame
refardancy, resulting in deterioration of physical properties inherent in
resins. Namely, there have been many problems practically. To solve
these problems, for example, a composite metal hydroxide is proposed in
Japanese Patent Provisional Publication (Tokkaihei) 6-41441. Compared
with a magnesium hydroxide, the composite metal hydroxide realizes
flame retardancy with less amount. However, when using zinc and
magnesium hydroxide for producing a composite metal hydroxide, basic
salts and oxides (zinc oxides) may be caused as by-products by
characteristics of zinc as a solid solution element in a conventional
method. In this way, It is difficult to obtain a composite metal hydroxide of
a uniform solid solution and realize expected properties thereof such as
flame retardancy and mechanical strength.
Accordingly, it is an object of the present invention to provide a
method of producing a composite metal hydroxide of a uniform solid
solution having excellent flame retardancy, a composite metal hydroxide
obtained thereby and a flame retardant high-molecular composition
superior In mechanical strength obtained thereby and therewith.
To accomplish the above object, a first gist of the invention relates
to a method of producing a composite metal hydroxide characterized by
reacting magnesium-containing aqueous solution (X) including water
soluble zinc compound wherein magnesium ion concentration is 0.01 to 1
mol/liter with alkaline material (Y) at a reaction equivalent ratio (X:Y) of
X:Y˜ 1:1.01 to 1:1.20.
A second gist of the invention relates to a method of producing a
composite metal hydroxide thereby wherein the produced composite metal
hydroxide is hydrot her malty treated at a temperature within a range of
100 to 2G0°C in chlorine-containing aqueous medium wherein chlorine ion
concentration is 0.5 to 2.0 mol/liter.
A third gist of ths invention relates to a method of producing a
composite metal hydroxide thereby wherein the produced metai hydroxide
is heated in the presence of reaction mother liquor at a temperature within
a range of 30 to 150°C and only the crystal surface thereof is substituted
for nickel by adding water soluble nickel compound solution.
A forth gist of the invention relates to a composite metal hydroxide
obtained by a method according to the above first or second gist
represented by the following general formula (1);
Mg1-xZnx(OH)2 .....(1)
wherein x indicates a positive number within a range of 0.003 = x = 0.1.
A Fifth gist of the invention relates to a composite metal hydroxide
obtained by a method according to the third gist represented by the
following general formula (2);
Mg1.x.yZnxNiy(OH)2..................(2)
wherein x indicates a positive number within a range of 0.003=
X = 0.1
and y indicates a positive number within a range of 0.01iy
= 0.05
A sixth gist of the invention relates to a flame retardant high-
molecular composition containing a composite metal hydroxide
represented by the general formula (1) or (2) within a range of 80 to 150
parts by weight based on 100 parts by weight of the high-molecular
composition.
It is difficult to stably produce a composite metal hydroxide of a
uniform solid solution with Mg in conventional methods, since a stable
crystal shape for a hydroxide is not hexagonal. For this reason, the
inventors of the present invention have piled up studies on reaction
processes for obtaining a uniform solid solution. Focused upon two points,
the inventors have further accumulated their studies; one is an Mg ion
concentration of Zn-containing Mg aqueous solution as a source of Mg
and the other is a reaction equivalent ratio of the Zn-ccntaining Mg
aqueous solution and alkaline material. As a result, they reached a
conclusion that a composite metal hydroxide of a uniform solid solution
represented by the above general formula (1) can be obtained by using
Zn-containing Mg aqueous solution wherein Mg ion concentration Is set
within a range of 0.01 to 1.0 mol/Jrter and reacting the Zn-containing Mg
aqueous solution (x) and the alkaline material (Y) at a reaction equivalent
ratio of (X:Y)=1:1.01 to 1:1.20. Further, they found out that occurrence of
secondary aggregation can be restrained because the crystal shape of
the composite metal hydroxide can be controlled by hydrothermally
treatlng the composite metal hydroxide obtained by reacting thereof at the
above reaction equivalent ratio in an aqueous medium having a specific
chlorine ion concentration within a temperature range of 100 to 200°C for
aging.
Still further, they reached the present invention that the composite
metal hydroxide represented by the general formula (2) wherein only the
crystal surface is substituted for Ni can be obtained by heating thus
obtained composite metal hydroxide within a temperature range of 80 to
150°C in the presence of reaction mother liquor and adding water soluble
Ni compound solution therein.
Even still further, they found out that the flame retardant high-
molecular composition wherein the composite metal hydroxide
represented by the general formula (1) or (2) is contained within a range of
80 to 150 parts by weight (just abbreviated to parts hereinafter) based on
100 parts of the high-molecular compound has superior flame retardancy
and satisfactory mechanical strength (such as tensile strength) even with
less content thereof compared with the conventional ones.
DISCLOSURE OF THE INVENTION:
Now, the present invention is described in detail.
The method for producing the composite metal hydroxide of the
present invention comprises three steps roughly.
That is, the first step is a reaction step for producing the composite
metal hydroxide represented by the following general formula (1) by
reacting Zn-contalnlng Mg aqueous solution having a specific Mg Ion
concentration and alkaline material at a specific equivalent ratio. This first
reaction step is preferable conducted within a temperature range of 10 to
35°C.
Mg1-xZnx(OH)2 .... (1)
wherein x represents a positive number within a range of
0.003=x=0.1
In the general formula (1), x value less than 0.003 is solid solution
amount insufficient for emerging the expected effect of the composite
metai hydroxide (superior flame retardancy). in the meantime, x value
over 0.1 results in difficulty In forming a uniform solid solution, causing
basic salts and oxides as by product, since an ion radius of zinc is larger
than that of magnesium. Further, it is difficult to control a crystal shape
and easy to cause secondary aggregation, which does not bring about the
expected effect of the composite metal hydroxide.
As the Zn-containing Mg aqueous solution, such an aqueous
solution that Zn compound Is added into Mg aqueous solution is
enumerated. As a source of the Mg aqueous solution, diluted bittern, sea
water, magnesium nitrate and the like are enumerated in which Mg ion
concentration should be set within a range of 0.01 to 1 mo (/lifer. Preferably
it is within a range of 0.03 to 0.3 mol/liter, Namely, for example, when
diluted bittern or sea water is adopted, Mg ion concentration over 1
mol/ltter overwhelmingly causes by-products of basic salts, resulting in
difficulty in forming a uniform solid solution. In addition, the Mg Ion
concentration may be measured by a chela to metric titration method, an
ICP emission spectrochemical analysis and the like. Measurement Is,
however, not critical as long as It is a method for analyzing ion
concentration in aqueous solution generally.
As the Zn compound to be added into the Mg aqueous solution,any
wafer soluble zinc compound such as zinc nitrate or zinc chloride is
included with no limitation. The addition amount thereof based on the Mg
aqueous solution is preferably set within a range of 0.3 to 10 mol% based
on the Mg in the aqueous solution, more preferably 1 to 7 mol%. Namely
the addition amount less than 0.3 mol % is too small an amount of solid
solution to emerge the expected effect of a composite metal hydroxide. On
the other hand, that over 10 mol % results in difficulty In forming a uniform
solid solution since a zinc ion radius is larger than that of magnesium,
causing basic salts and oxides as by-products. Further, it is difficult to
control a crystal shape and easy to cause secondary aggregation, which
shows a tendency that the expected effect of the composite metal
hydroxide cannot be emerged.
Still further, as the alkaline material to be reacted with the Zn-
containlng Mg aqueous solution having a specific Mg Ion concentration,
calcium hydroxide, sodium hydroxide and the like are enumerated.
Furthermore, the reaction ratio of the Zn-containing Mg aqueous
solution (X) and the alkaline material (Y) at the first step is needed to be
set at the equivalent ratio (X:Y)=1:1.01 to 1:1.20. Preferably, it Is set at
X:Y=1:1.03 to 1:1.10. Namely, when the alkaline material (Y) is less than
1.01 or the reaction equivalent ratio, by-products of basic salts may be
identified, preventing formation of a uniform solid solution thereby, while
when it is over 1.20, by-products of oxides may be identified, causing
difficulty in controlling a crystal shape resulting in easiness in occurrence
of secondary aggregation.
The preferable combination of the Zn-containing Mg aqueous
solution and the alkaline material at the first step is to adopt sea water (Mg
aqueous solution) wherein zinc chloride, water soluble zinc compound,is
added into Zn-containing Mg aqueous solution and calcium hydroxide
(limemilk) as an alkaline material in view of stability of the produced
composite metal hydroxide and the manufacturing cost.
Subsequently, a method of the second step following the method of
producing the composite metal hydroxide as the above first step is
described here.
The second step comprises thermally treating the composite metal
hydroxide represented by the general formula (1) produced in the first step
in chlorine-containing aqueous medium with a specific chlorine ion
concentration within a temperature range of 100 to 2000C to be aged.
As the chlorine-containing aqueous medium, aqueous solutions of
calcium chloride, sodium chloride, magnesium chloride, potassium
chloride and the like are enumerated. Among all, it is preferably to adopt
calcium chloride aqueous solution as the chlorine-containing aqueous
medium in view of controllability of the crystal shape of the composite
metal hydroxide. Further, the chlorine ion concentration in the chlorine-
containing aqueous medium should be set within a range of 0.5 to 2
mol/liter. Preferably, it is within a range of 0.5 to 1.0 mol/llter. Namely, low
concentration of chlorine ion less than 0.5 mol/liter may cause insufficient
controllability of a crystal shape of the composite metal hydroxide,
resulting in the easiness in occurrence of secondary aggregation. On the
other hand, that over 2 mol/Wer may cause basic salts and oxides as by-
products, resulting in difficulty in forming a uniform solid solution. In
addition, the chlorine ion concentration may be measured by a general
method for analyzing ion concentration in solution, such as a
chelatometrlc tltration method or an ICP emission spectrochemical
analysis.
Even further, as the aging conditions for the thermal treatment, the
temperature should be set within a range of 100 to 200°C and the
pressure should be within a range of 0.5 to 10 kg/cm2 concomttantiy.
Thus obtained composite metal hydroxide is represented by the
general formula (1). The crystals may further grow and secondary
aggregation may decrease through the second step, which results in more
preferable flame retardants in view of various properties such as
compatibility with a high-molecular compound, disperisibility, appearance
of the formed product or mechanical strength.
Next, the third step following the method of producing the
composite metal hydroxide as the second step is described. The
composite metal hydroxide obtained by this step is such as represented
by the general formula (2), a solid solution comprising three metals of Mg,
Zn, and Ni.
Mg1-x-yZnxNly(OH)2.................(2)
wherein x represents a positive number within a range of
0.003=y=0.1 and y represents a positive number within a range of
0.01=y=0.05.
In the general formula (2), x value less than 0.003 is too small an
amount of solid solution to emerge the expected effect (superior flame
relardancy) of a composite metal hydroxide. On the other hand, that over
0.1 mol % results in difficulty in forming a uniform solid solution since an
Ion diameter of zinc is larger than that of magnesium, causing by-products
of basic salts and oxides. In addition, it may cause difficulty in controlling a
crystal shape and easiness in occurrence of secondary aggregation,
which does not bring about the expected effect of composite metal
hydroxide. In the meantime, y value less than 0.01 may cause
insufficiency of nickel substitution amount on the crystal surface, which
does not fully emerge the expected effect of the composite metal
hydroxide, in addition, that over 0.05 may cause cost increase and also
saturation of the nickel substitution amount on the crystal surface,
resulting in by-products of free nickel hydroxide and the like.
In the third step, the composite metal hydroxide represented by the
general formula (1), which was produced in the second step, is heated in
the presence of reaction mother liquor within a temperature range of 80 to
150°C and water soluble nickel compound solution is added therein so as
to substitute only the crystal surface for Nl, resulting In the composite
metal hydroxide represented by the general formula (2).
As the water soluble nickel composite solution, aqueous solutions
of nickel chloride, nickel nitrate and the like are enumerated. Among all, It
is preferable to use nickel chloride in view of reactivity with composite
metal hydroxide. Further the mixing ratio of such water soluble nickel
compound solution is preferably set within 1 to 5 moi % based on the
composite metal hydroxide of a reaction mother liquor. Particularly, it is
preferable to be within 1 to 3 moi %.
In the meantime, a heating condition in adding water soluble nickel
compound solution, as mentioned above, is set within a temperature
range of 80 to 150°C. Particularly, it is preferable to set within a
temperature range of 90 to 120°C. By setting as such, It becomes possible
to substitute only the crystal surface effectively for nickel. Namely the
lower temperature may cause free nickel hydroxides as by-products due
to insufficient substitution. On the other hand, the higher temperature may
cause excessive nickel substitution extending into the inside of crystal
structure. In both ways, the expected effect is not realized.
Thus, as the composite metal hydroxide represented by the general
formula (1) through the first or second step, or represented by the general
formula (2) through the third step, the crystal size is 0.2 to 4 mm, more
preferably 0.2 to 2pm, most preferably 0.5 to 1.5 mm, and that with almost
no or less secondary aggregation, which means that the average
secondary particle size is 0.2 to 4mm, more preferably 0.2 to 2 mm, most
preferably 0.5 to 1.5pm, and also a BET specific surface area is 1 to 20
mVg, preferably 3 to 15 m2/g, most preferably 6 to 12 m2/g. Namely, since
each value for the composite metal hydroxide is set within a range as
above, it becomes possible to retain superior effects in compatibility with
high-molecular com pounds such as resin or rubber, dispersibility, forming
capability, appearance of the formed products, mechanical strength and
the Wee to be mentioned below. In addition, the above average secondary
particle diameter is a value measured by the microtrack method on
sample powder, which was dispersed by as ultrasonic treatment, in 0.2%
sodium hexametaphosphate aqueous solution.
The BET specific surface area is a value in accordance with an N2
adsorption method.
Thus obtained composite metal hydroxide represented by the
above general formula (1) or (2), may be used as a flame retardant as it is,
however, it may possible to additionally conduct surface treatment with
finishing agents such as various fatty acids, phosphoric acid ester,
coupling agents and the like. The various finishing agents may be used
solely or in combination of two or more.
As the various fatty acids, higher fatty acids having 10 or more
carbon atoms such as stearic acid, oielc acid, erucic add, palmitic acid,
lauric acid and behenic acid, and alkall metal salts thereof may be listed,
in addition, as the phosphate esters, mono-or diesters of orthophosphoric
acid with oleyi alcohol or stearyl alcohol, mixtures of these, acid type or
alkali metal salts or amine salts thereof may be listed.
As the above couplings agents, silane-coupling agents such as
vinylethoxysilane, vinyl-tris(2-methoxy-ethoxy)silane
methacryloxypropyltrimethoxysllane,
grycidioxypropyltrimethoxysilane,
aminopropyitrimethoxysiiane
epoxycyclohexyl)ethyltrimethoxysilane,
mercaptopropyftrlmethoxysllane, tltanate coupling agents such as
isopropyltrisostearoyl titanate, isopropyitris (dioctylpyrophosphate)titanate,
isopropyltrl(N-aminoethyl-aminoethyl) titanate and
isopropyitridecyibenzenesulfonyi titanate; aluminium coupling agents such
as acetoalkoxyalminium diisopropylate.
As the above surface treatment with various finishing agents, a
conventional moisture or dry method is available, with no limitation.
Then, by adding the composite metal hydroxide represented by the
general formula (1) or (2) as a flame retardant into the high -molecular
compound, a flame retardant having high-molecular composition can be
obtained.
As the above high-molecular compound, general resin, rubber and
the like may be emumerated. For example, a copolymer of polyethylene or
ethylene with other a-olefin, a copolymer of ethylene with vinyl acetate,
ethyl acrylate or methyl acrylate, polypropylene, a copolymer of propylene
with other a-olefin, polybutene-l, polystyrene, a styrene-acrylonltrile
copolymer, thermoplastic resin such as vinyl acetate, poryacrylate,
polymerchacrylate, polyurethane, polyester, polyether, pofyajmide,
thermosetting resins such as phenolic resin, melamine resin, epoxy resin,
unsaturated polyester resin, alkyd resin, ethylene-propylene-diene rubber,
stylene-butadine rubber, acrylonitrile-butadiene rubber, butyl rubber,
isoprene rubber, chlorosutfonated polyethlene and the like. These high-
moiecuiar compounds are appropreatefy selected.
At that time, the mixing ratio of the composite metal hydroxide
represented by the general formula (1) or (2) is selected appropreately
depending on the kinds of the above high-molecular compounds and the
like, it is set within a range of 80 to 150 parts by weight based on 100
parts of the high-molecular compounds. Particularly, it is preferably 100 to
130 parts. Namely, the mixing ratio thereof less than 80 parts may cause
insufficient flame retardancy, while that over 150 parts may cause
deterioration in mechanical strength such as tensile strength. Further, the
composite metal hydroxide represented by the general formula (1) or (2)
may be used solely or In combination as long as its mixing ratio is set
within the above range.
Further, various additives may be added appropriately other than
the above composite metal hydroxide represented by the general formula
(I) or (2) into the flame retardant high-molecular composition of the
present invention. For Example, a general flame retardant aid such as
carbon fine powder, red phosphorus is enumerated. Moreover, lubricants,
antioxidants, ultraviolet inhibitors, antistatic agents, pigments, foaming
agents, plasticizers, fillers, reinforcing materials, crosslinking agents and
the like are enumerated.
The flame retardant high-molecular compound can be obtained by
adding the composite metal hydroxide represented by the general formula
(1) or (2) into the high-molecular compound at a specific ratio, mixing and
then kneading thereof. As a method for mixing and kneading thereof,
conventional methods such as single-screw or twin-screw extruder, a roll,
Banbury mixer and the like may be enumerated with no limitation.
Then, as a method for forming with thus obtained flame retardant
high-molecular compound, a suitable molding method is selected
appropriately depending on the kinds of the high-molecular compounds,
the kinds of desired molded products and the like with no limitation. For
Example, Injection molding, extrusion blow molding, press molding,
rotational molding, calendering, sheet forming, transfer molding, laminate
molding, vacuum molding and the like may be enumerated.
Further, a solid solution containing Zn and Mg cannot be obtained
by the methods disclosed by EP 9230773.6 (hereinafter Just referred as
D1) and EP 92310744.5 (hereinafter just referred as D2). Only Zn is an
amphoteric metal among Mn, Fe, Co, Nl, Cu and Zn, which are disclosed
as divalent metals in D1 and D2, and Zn hydroxide in substantially
unstable. Therefore, if reaction conditions such as reaction solution pH
and mother liquor concentration are not maintained appropriately in
producing a solid solution containing Zn and Mg by reacting aqueous
solution thereof, basic salts and oxides may be caused as by-products,
resulting in a difficulty in producing a uniform Zn solid solution.
A reaction equivalent ratio of 0.5 to 0.95 disclosed in D1 and D2 is
within such a range as causes basic salts.
On the contrary, to solve the above problems, reaction solution pH
is within an appropriate range of an alkaline side by adjusting a reaction
equivalent ratio within 1.01 to 1.20, and by-production of basic salts is
restrained by lowering mother liquor concentration, resulting in a uniform
Zn solid solution.
Namely, among products disclosed in D1 and 02, the products
containing Zn as a divalent metal is not a uniform solution of Zn and Mg,
but a mixture of magnesium hydroxide and basic zinc chloride.
Therefore, it Is obvious that the product of the present Invention
differs from those of 01 and D2, and flame retardancy cannot be realised
from magnesium hydroxide solid solutions of D1 and D2. This is described
in the following Examples 11 to 15 and Comparative Examples 8 to 10.
Further, the crystal of the composite metal hydroxide of EP
92304925.8 (hereinafter just referred as D3) is long and fibrous, and has a
length/diameter ratio of about 10 or more, an average diameter of
approximately 0.1 to 10 urn and an average length of approximately 2 to
1000 urn.
On the contrary, the crystal of the composite metal hydroxide of the
present invention Is a hexagonal plate, and has an average diameter of
0.2 to 4 urn, an average thickness of 0 1 to 0.5 urn, and an aspect ratio
(diameter/thickness ratio) of not more than 10.
Further, the method of the present invention differs from that of D3.
The method of D3 comprises the steps of adding an aqueous
solution of the divalent transition metal of the formula M2+ A- 2 wherein M
is a divalent metal such as Mn into an aqueous solution of magnesium salt
represented by the formula MgA2 containing the acicular-crystal
magnesium salt represented by the formula Mg(OH)2-y A-y • mH2O
wherein A" is a monovalent anion with stirring, for obtaining the acicular-
crystal basic magnesium salt represented by the formula M2+ x Mg1-x
(OH)2-zA-z. mH2O, dehydrating thus obtained acicular-crystal basic
magnesium salt, washing thereof with water, and then contacting the
acicular-crystal basic magnesium salt with alkali such as sodium
hydroxide In liquid medium such as water for reaction so as to substitute
A z with OH " thus, the fibrous composite metal hydroxide can be
obtained.
On the contrary, a method of producing a composite metal
hydroxide of the present invention comprises the steps of reacting
magnesium-containing aqueous solution (X) including water soluble zinc
compound wherein magnesium Ion concentration is 0.01 to 1 mol/llter with
alkaline material (Y) at a reaction equivalent ratio (X;Y) of X;Y=1 1 01 to
1:1.20.
EXAMPLE 1
By dissolving zinc chloride, a reagent of the first grade, into ionic bittern
and diluting thereof with deiontzed water. 300-liter mixture aqueous
solution with 0.14 mot/liter Mg ion concentration and 0.008 mo I/liter Zn ion
concentration was produced. In the meantime, as the alkaline material ,
51-liter limemilk with 0.9 mot/liter was produced. Both of them were mixed
in such as manner that the reaction equivalent ratio is mixture aqueous
solution;(imemilk=1;1.03 by charging thereof consecutively with stirring
into a continuous reaction vessel of 50-liter effective volume. Then, this
reactant was emulsified into calcium chloride aqueous solution with 1.0
mol/liter chlorine ion concentration, and thermally treated at 150°C for two
hours by putting thereof into an autoclave of 100-liter effective volume with
a stirrer. Thereafter, it was filtrated by a filter press, washed with water,
dehydrated, dried in an oven and then pulverized, thus producing the
composite metal hydroxide as an objective.
EXAMPLE 2
Em unification of the reactant in example 1 was conducted in sodium
chloride aqueous solution with 0.5 mol/liter chlorine ion concentration and
the thermal treatmeftt was conducted at 170°C for two hours. Except for
that, example 2 was the same as example 1, thus producing the
composite metal hydroxide as an objective.
EXAMPLE 3
By dissolving zinc nitrate, a reagent of the first grade, into ionic bittern and
diluting thereof with deionized water, 50-liter mixture aqueous solution with
1.0 mol/liter Mg ion concentration and 0.003 mol/liter Zn ion concentration
was produced. In the meantime, as the alkaline material, 52-liter lime milk
with 1.0 mol/liter was produced. Both of them were mixed in such a
manner that the reaction equivalent ratio is mixture aqueous
solutlon:limemilk=1:1.04 by charging thereof consecutively with stirring
into a continuous reaction vessel of 10-liter effective volume. Then, this
reactant was emulsified into sodium chloride aqueous solution with 2.0
mol/liter chlorine ion concentration, and thermally treated at 150°C for two
hours by putting thereof into an autoclave of 100-liter effective volume with
a stirrer. Thereafter, it was filtrated by a fitter press, washed with water,
dehydrated, dried in an over and the pulverized., thus producing the
composite metal hydroxide as an objective.
EXAMPLE 4
The reaction equivalent ratio of the mixture aqueous solution and iimemilk
of example 3 was changed In such a manner that mixture aqueous
solutlon.llmemllk=1.1,20. Except for that, example 4 was the same as
example 3, thus producing the composite metal hydroxide as an objective.
EXAMPLE 5
By dissolving magnesium nitrate and zinc nitrate, reagents of the first
grade, Into delonized water, 1-llter mixture aqueous solution with 0.9
mot/liter Mg ion concentration and 0.1 mol/liter Zn ion concentration was
produced, in the meantime, as the aikaiine material, 1-llter sodium
hydroxide aqueous solution with 2.04 mol/ltter was produced. Both of them
were mixed in such a manner that the reaction equivalent ratio is mixture
aqueous solution : sodium hydroxide-1:1.02 by dropping the mixture
aqueous solution into sodium hydroxide aqueous solution with stirring,
thus producing reactant. This reactant was emulsified into sodium chloride
aqueous solution with 1,0 mol/liter chlorine ion concentration, and
thermally treated at 150r"C for two hours by putting thereof into an
autoclave of 3-Ilter effective volume with a stirrer and thereafter, filtrated
by a vacuum filter, washed with water, dehydrated, dried in an oven and
then pulverized, thus obtaining the composite metal hydroxide as an
objective.
EXAMPLE 6
Synthetic sea water was produced by adding zinc nitrate into 1530-liter
decarboxyiated sea water (Mg ion concentration: 0.032 mo (/liter) in such a
manner that Zn ion concentration was 0.002 moi/iiter. In the meantime, as
the alkaline material, 51-liter Hmemilfc with 1.07 mol/liter alkali ion
concentration was produced. Then, both of them were mixed in such a
manner that the reaction equivalent ratio is synthetic sea
water:llmemllk=1:1.05 by charging (hereof consecutively with stirring into a
continuous reaction vessel of 250-liter effective volume. Then, this
reactant was emulsified into calcium chloride aqueous solution with 1.2
mol/liter chlorine ion concentration, and therm airy treated at 150°C for two
hours by putting thereof into an autoclave of 100-liter effective volume with
a stirrer. Thereafter, it was filtrated by a fitter press, washed with water,
dehydrated, dried in an oven and then pulverized, thus producing the
composite metal hydroxide as an objective.
EXAMPLE 7
The reaction mother liquor after being thermally treated at 150°C for two
hours In example 6 was cooled down to 100°C. And 3.5-liter nickel
chloride aqueous solution with 0.3 mot/liter Ni ion concentration was
added therein with stirring for aging with heating at 100°C for 30 minutes.
Except for that, example 7 Is the same as example 6.
EXAMPLE 8
The ratio of nickel chloride aqueous solution based on the produced
composite metal hydroxide was changed to 1 mol % Except for that,
example 8 was the same as example 7.
EXAMPLE 9
The ratio of nickel chloride aqueous solution based on the produced
composite metal hydroxide was changed to 5 moI % and the aging
condition with heating was changed to 150°C for 30 minutes. Except for
that, example 9 was the same as example 7.
EXAMPLE 10
The reaction mother liquor after being thermally treated at 1S0°C for two
hours in example 3 was cooled down to 100°C, And 3.9 liter nickel
chloride aqueous solution with 0.4 mo I/liter Ni ion concentration was
added therein with stirring for aging with heating at 100°C for 30 minutes.
Except for that, example 10 is the same as example 6.
COMPARATIVE EXAMPLE 1
By dissolving zinc chloride, a reagent of the first grade, into bittern, 30-liter
mixture aqueous solution with 1.7 mol/liter Mg ion concentration and 0.085
mol/Irter Zn ion concentration was produced, In the meantime, as thB
alkaline material, 46-liter lime milk with 1.0 mol/liter alkaline ion
concentration was produced. There, both of them were charged into a
continuous reaction vessel of 2.5 -liter effective volume with stirring for
reaction in such a manner that mixture aqueous solution:limemilk=1:0.9 at
a reaction equivalent ratio. Further, this reactant was put into an autoclave
of 100-liter effective volume with a stirrer for thermal treatment at 150°C
for two hours. Thereafter, It was nitrated by a niter press, washed with
water, dehydrated, dried In an oven and then pulverized, thus producing
the composite metai hydroxide as an objective.
COMPARATIVE EXAMPLE 2
The reaction equivalent ratio of the mixture aqueous solution and the
lime milk was changed to 1:1.05. Except for that, comparative example 2
was the same as comparative example 1 so as to obtain the resultant
product.
COMPARATIVE EXAMPLE 3
The reaction equivalent ratio of the mixture aqueous solution and the
sodium hydroxide of example 5 was changed to 1:1.25. Except for that,
comparative example 3 was the same as example 5 so as to produce the
resultant product.
COMPARATIVE EXAMPLE 4
The reaction equivalent ratio of the mixture aqueous solution and the
sodium hydroxide of example 5 was changed to 1:1.00. Except for that,
comparative example 4 was the same as example 5 so as to produce " the
resultant produce.
COMPARATIVE EXAMPLE 5
A mixture aqueous solution of 1.1 mol/liter Mg ion concentration and 0.055
mol/ltter Zn ion concentration was produced. In the meantime, the reaction
equivalent ratio for the mixture aqueous solution and the lime milk was set
at 1:1.05. Except for that, comparative example 5 was the same as
comparative example 1.
COMPARATIVE EXAMPLE 6
The mixture aqueous solution of example 1 was changed to that of 0.14
mol/liter Mg ion concentration and 0.019 mot/liter Zn ion concentration.
Except for that, comparative example 6 was the same as example 1.
COMPARATIVE EXAMPLE 7
The mixture aqueous solution of example 1 was changed to that of 0 88
mol/liter Mg ion concentration and 0.12 mot/liter Zn ion concentration.
Except for that, comparative example 7 was the same as example 1.
Each chemical composition, average secondary particle diameter
and BET specific surface area of thus obtained various composite metal
hydroxides was measured. The results are shown in the following tables 1
and 2.
The chemical composition was quantitatively determined by an x-
ray fluorescence analysis, and a cheiatometric titration method, an ICP
emission spectrochemical analysis or the like on the mixture wherein a
composite metal hydroxide was solved into hydrochloric acid for
quantification of content by element, and also identified and measured on
lattice constant by x-ray diffraction to judge whether a uniform solid
solution was realized or not.
The above average secondary particle size was measured by a
microtrack method after conducting ultrasonic dispersion treatment on
sample powder in 0.2% sodium hexametaphosphate aqueous solution.
The BET specific surface area was measured by an N2 adsorption
method.
From the above tables 1 and 2, it is found out that a uniform solid
solution was obtained in every example.
EXAMPLES 11 TO 15
Next, each composite metal hydroxide (of examples) shown in the
following table 3 was suspended into water respectively, heated up to
70°C with stirring. Subsequently, sodium oleate dissolved in advance was
added into the composite metal hydroxide by 2 weight % as oleic acid so
as to be surface treated. Then, it was dehydrated, washed with water and
dried in an oven.
Further, as a specimen, 0.2 parts antioxidant and each composite
metal hydroxide (of examples), surface treated at ratios shown in the
following table 3, were added based on 100 parts ethylene-ethylacrylate
coporymer (ethylene acrylate content; 15 weight %, Nippon
Petrochemicals Co. Ltd) so as to be mixed in a blender. After being mixed,
it was kneaded by an open-roll mixer at 130°C and further press-molded
at 160°C so as to be made into a sheet in 1 mm thickness and a sheet in
about 3.2 mm thickness (1/8 inch) respectively. Then, each of the sheets
was punched Into a dumbbell-shape and a strip-shape as samples
respectively. These samples were subjected to a tensile test in
accordance with JIS C3005 and a combustibility test in accordance with
UL94VE.
COMPARATIVE EXAMPLES B TO 11
Each reaction product (of comparative examples) and Mg(QHh
shown In the following table 4 were mixed at ratios specified therein .
Except for that, each sheet was formed in the same way as that of
examples 12 to 19. Then, each sheet was punched into a dumbbell-shape
and a stripe-shape as specimens. These specimens were subjected to a
tensile test in accordance with JIS C300S and a combustibility test in
accordance with UL94VE.
The results of tensile strength and combustibility tests by using these
specimens are shown in the following tables 5 and 6.
From the above tables 5 and 6, it is found out that all comparative
examples were low in tensile strength and inferior in mechanical strength.
Further, good results were not obtained for flame retardancy on
comparative examples 8 to 10. On the other hand, good results were
obtained for flame retardancy on ail examples although composite metal
hydroxides were less added than in comparative examples. Still further,
tensile strength on examples was superior to that of ail comparative
examples, which shows that all examples retain high flame retardancy as
well as mechanical strength.
EFFECTS OF THE INVENTION
As the above, the composite metal hydroxide represented by the general
formula (1) is produced by reacting Zn-confalning Mg aqueous solution
having a specific Mg ion concentration and alkaline material at a specific
reaction equivalent ratio. For this reason, a composite metal hydroxide, a
uniform solid solution, wherein Zn is solid solved Into Mg system, which Is
difficult to produce in the conventional methods can be obtained. Further,
the composite metal hydroxide obtained at this reaction equivalent ratio is
aged in aqueous medium having a specific chlorine ion concentration at a
specific temperature so as to produce the composite metal hydroxide
represented by general formu!a(1), whose crystal shape can be controlled,
which prevents occurrence of secondary aggregation.
in addition, the composite metal hydroxide represented by the general
formula (2) wherein only the crystal surface is substituted for Ni can be
obtained by adding water soluble Ni compound solution into the composite
metal hydroxide represented by the general formula (1) at a specific
temperature in the presence of reaction mother liquor. Thus obtained
composite metal hydroxide is a uniform solid solution wherein Zn is solid
solved into Mg system. Therefore, the flame retardant high-molecular
composition obtained by mixing the composite metal hydroxide
represented by the general formula (1) or (2) at a specific volume based
on the high-molecular compound exerts high flame retardancy with less
content thereof compared with the conventional ones and shows
superiority in mechanical strength.
WE CLAIM:
1. A method of producing a composite metal hydroxide of general formula
Mg1-x-yZnxNIy(OH)2.........(2)
comprising the steps of heating the composite metal hydroxide of general
formula (1)
Mg1-xZnx(OH)2.........(1)
in the presence of reaction mother liquor at a temperature within a range
of 80 to 150°C and substituting Nl for at least one of Mg and Zn on the
crystal surface thereof, by adding a solution of a water-soluble nickel
compound such as aqueous solutions of nickel chloride, nickel nitrate and
the like.
This invention relates to a method of producing a composite metal hydroxide
comprising the steps of heating the composite metal hydroxide in the presence of
reaction mother liquor at a temperature within a range of 80 to 150°C and
substituting Ni for at least one of Mg and Zn on the crystal surface thereof, by
adding a solution of a water-soluble nickel compound such as aqueous solutions
of nickel chloride, nickel nitrate and the like.

Documents:

00539-cal-2002-abstract.pdf

00539-cal-2002-claims.pdf

00539-cal-2002-correspondence.pdf

00539-cal-2002-description (complete).pdf

00539-cal-2002-form 1.pdf

00539-cal-2002-form 26.pdf

00539-cal-2002-form 3.pdf

00539-cal-2002-form 5.pdf

00539-cal-2002-letter patent.pdf

00539-cal-2002-priority document others.pdf

00539-cal-2002-priority document.pdf

00539-cal-2002-reply f.e.r.pdf

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Patent Number

212142

Indian Patent Application Number

539/CAL/2002

PG Journal Number

47/2007

Publication Date

23-Nov-2007

Grant Date

20-Nov-2007

Date of Filing

13-Sep-2002

Name of Patentee

TATEHO CHEMICAL INDUSTRIES CO. LTD.,

Applicant Address

974, AZAKATO, KARIYA, AKO-SHI, HYOGO 670-02 JAPAN.

Inventors:

#	Inventor's Name	Inventor's Address
1	KURISU HIROFUMI	1327-226, KIZU, AKO-SHI, HYOGO 678-01, JAPAN.
2	KODANI TOSHIKAZU	2126-1, SHIOYA, AKOVSHI, HYOGO 678-02, JAPAN.
3	KAWASE ATSIUA	1070-1-402, NAKAHIRO, AKO-SHI, HYOGO 678-02, JAPAN.
4	OKI TAKASHI	2124-10, SHIOYA, AZO-SHI, HYOGO, 678-02, JAPAN.

PCT International Classification Number

C08L 101/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	7-198786	1995-08-03	Japan