NO118726B - - Google Patents

Description

Process for the production of polymeric phosphates from copolymers of epoxy monomers and acyclic epoxy-free monomers.

The present invention relates to a new class of polymeric substances and their production

ling. More particularly, the present invention relates to copolymers containing phosphoric acid ester groups, these copolymers being soluble in organic solvents,

and it relates to coating compositions containing these copolymers.

The starting material for the polymers according to the present invention are special copolymer epoxides. Polymeric epoxides are polymers that contain epoxy-

groups

also called oxirane groups. A number of polymers of this type are known, e.g. polymers containing glycidyl groups,

One purpose of the present invention is to provide new copolymer substances and a method for their production.

A further purpose is to obtain a new class of copolymers, which contain phosphoric acid ester groups. A further purpose is to obtain reaction products of epoxy copolymers with phosphoric acid, all of which are soluble in organic solutions, with some being soluble in aqueous alkaline solutions.

ger, and others are insoluble in such aqueous alkaline solutions. A further purpose is to obtain coating compositions containing the new polymeric products) according to the present invention as film-forming material.

The purpose of the present invention is achieved by obtaining polymeric phosphates which

are the reaction products of a polymeric epoxide copolymer and phosphoric acid in an amount that is at least approx. half a mole per oxyran oxygen atom in the aforementioned copolymer, the polymeric epoxide copolymer having an epoxide oxygen content that lies within the range 0.3 to 8% by weight and which contains an amount of

for the range 3 to 60% by weight of a polymer

cert, ethylenically unsaturated epoxy monomer and an amount within the range of 97

to 40% by weight of a polymerized, ethylenically unsaturated acyclic epoxy-free monomer. These polymeric phosphates are soluble in organic solvents and are useful as film-forming agents in coating compositions.

The new polymeric phosphoric acid esters according to the present invention can be obtained by allowing phosphoric acid to react in an inert solvent and at a temperature below 100° C with a polymeric epoxide, which is a copolymer of a polymerizable ethylenically unsaturated epoxy compound, with a polymerizable ethylenically unsaturated acyclic compound, which is free of epoxy groups,

in that the aforementioned components are present in the copolymer in the weight ratio between polymerized epoxy monomer and polymeri-

cemented epoxy-free monomer that lies within the range 3:97 to 60:40, the phosphoric acid being used in an amount that is at least approx. half a mole per oxyran oxygen atom in the said copolymer. Some of the products according to the present invention are alkali-soluble, and the invention thus also includes the salts of the previously mentioned polymeric phosphates and in particular their water-soluble alkali metal and ammonium

salts, which. also includes substituted ammonium salts.

The structure of the polymeric phosphates according to the present invention is not known with certainty, but it is assumed that in all cases these products are linear, or substantially linear, polymers which are contained as side substituents-for acid ester groups,

which occurs when the epoxy groups are opened according to the following scheme:

Analysis by means of electrometric titration with alkali suggests that there are two inflection points in the titration curve, which suggests the presence of essentially two acid hydrogen atoms per phosphate group in the polymer. Titrations, where thymolphthalein is used as an indicator, give acid values which, based on the phosphate content, also suggest the presence of two acid hydrogen groups per phosphate group in the -polymer.

The polymeric phosphates according to the present invention are conveniently prepared by treating a solution of a polymeric epoxide of the type defined above with approx. 20% solids in an inert solvent with phosphoric acid at a temperature in the range of 50 to 100° C for a period of half to three hours or at a normal temperature of 20-25° C for longer periods of approx. 15-25 hours. As already mentioned, at least approx. half a mole of phosphoric acid per oxyran oxygen. Under such conditions little or no cross-linking takes place between the polymeric molecules. Some of the products are soluble in aqueous alkali and in some cases also soluble in water. Partial or complete neutralization of this type of polymeric phosphates with alkali hydroxides, ammonia or an amine, e.g. an alkylamine of 1 to 4 carbon atoms, they give alkali, ammonium or substituted ammonium salts which are water-soluble. In some cases, the polymeric phosphates are insoluble in dilute aqueous alkali (which, for accuracy's sake, is

defined as 5% aqueous sodium hydroxide). In all cases, however, they are polymeric

phosphates according to the present invention

soluble in organic solvents, e.g. acetone.

The factors responsible for the solubility or insolubility in water

alkali in the polymeric phosphates according to the present invention is of a complex nature. However, the main factors seem to be the extent of phosphate ion, i.e. the amount of - H2PO4 groups in the polymeric phosphates, and the nature and composition of the starting copolymers.

The alkali-soluble polyphosphates are generally obtained by starting from a copolymer

which contains over approx. 3.9% by weight

oxyranoxygen, and by allowing such a copolymer to react with at least one mole of phosphoric acid per oxirane group. This oxyran oxygen content corresponds to a calculated phosphate content, calculated as - H2P04, of approx. 19% in the resulting polymeric phosphate.

The alkali-insoluble polyphosphates are generally obtained by allowing the epoxy copolymer to react with phosphoric acid in an amount based on the oxyranoxygen, which is lower than that calculated to give approx. 19% - H2PO4 in the resulting polyphosphate. This can be done by using copolymers that contain less than approx. 3.9% oxyranoxygen and allowing copolymers to react with at least approx. 0.5 mol phosphoric acid per oxirane-oxygen, or it can be done by starting from a copolymer with a higher oxirane-oxygen content than approx. 3.9% by allowing such a part of the epoxy group of the copolymer to react with phosphoric acid, that the calculated - H2PO4 content in the resulting polyphosphate is less than approx. 19% by weight.

It will be clear to a chemist that the values for the oxyranoxygen content and the corresponding calculated phosphate content as determining factors in the alkali solubility in relation to the insolubility may vary somewhat from what is stated above due to the influence of other factors, such as the nature of the comonomers and for the copolymers derived from these, the molecular weight of the copolymers and the reaction conditions. For example, it has been found, with respect to epoxy monomers, that glycidyl ether monomers, such as allyl glycidyl ether, react more readily with phosphoric acid than glycidyl esters, such as glycidyl methacrylate. The nature of the epoxy-free monomers also causes variations.

It has been found that copolymers containing polymerized vinyl carboxylates, such as vinyl acetate, i.e. polymers containing acyloxy groups form polyphosphates which deviate from the general limitations described above with respect to the phosphate content required to induce alkali solubility. Such polyphosphates have been found to be soluble in alkali even with calculated phosphate content, which is well below 19%. This is also the case with polyphosphates of epoxy copolymers, in which the epoxy-free component is a polymerized methacrylic acid ester of an alcohol containing a water-solubilizing group, such as an ether group, e.g. beta-methoxyethyl methacrylate.

The invention will be described in more detail in the following examples, in which parts mean parts by weight. The examples also show some of the most important among the many uses of these polymers, namely their use in coating compositions, as impregnation for textile fibers and as agents in the treatment of leather.

Examples I-VI explain the preparation of alkali-soluble polyphosphates from epoxy copolymers in which the polymerized epoxy-free monomer is free of acyloxy groups.

Example 1:

A copolymer of allyl glycidyl ether and butyl methacrylate was produced by setting at a constant rate over a period of approx. 2 hours a solution of 852 parts butyl methacrylate, 342 parts allyl glycidyl ether and 36 parts di-tertiary butyl peroxide to 1149 parts allyl glycidyl ether, which was heated to 230°C (+2°C) under a nitrogen atmosphere. After the addition was complete, the polymer isas ion mixture was heated to 130-132°C for an additional period of 1 hour. The unchanged monomers were then removed by distillation under a pressure of 0.1-1 mm of mercury, as it was heated to approx. 100° C. There remained 1258 parts of a polymer which was soft and viscous at 100° C. This polymer contained approx. 4% oxirane oxygen (28% polymerized allyl glycidyl ether), which corresponded to an oxirane equivalent weight of approx. 400, and it had a molecular weight of approx. 1900.

A solution of 73 parts of this polymeric epoxide in 200 parts of acetone was added to 24 parts of 85% phosphoric acid (approx. 1.14 mol of phosphoric acid per oxirane oxygen). The temperature rose spontaneously to approx. 50° C due to the heat from the exothermic reaction. The reaction was completed by heating the mixture to boiling temperature (58° C) and was refluxed for approx.

1 hour. The polymeric phosphate is precipitated from up-

the solution by the addition of water, but it dissolved readily in dilute ammonium hydroxide or sodium hydroxide and could be reprecipitated from its alkaline solution by acidification.

A resolution of approx. 17% of this polymeric phosphate in dilute ammonium hydroxide gave, on evaporation, a clear, transparent, hard, tough film, which after curing by heating to 120° C. for approx. 20 minutes was insoluble in water and unaffected by most organic solvents.

Example 2:

A copolymer of glycidyl methacrylate,

and butyl methacrylate was prepared by heating for 2 hours at 80° C. a solution of 18 parts glycidyl methacrylate, 28.4 parts butyl methacrylate and 0.9 parts benzoyl peroxide in 110 parts dioxane. The conversion of monomer to polymer was over 90% of the theoretical. The copolymer contained 4.33% by weight oxyranoxygen, which corresponded to 38.4% polymerized glycidyl methacrylate, and it had a molecular weight of approx. 4000.

A solution of 2 parts of 85% phosphoric acid in 8 parts of methyl ethyl ketone was added with stirring to 5 parts of a 30% solution of the above-mentioned copolymer in dioxane (approx. 4.3 mol of phosphoric acid per oxirane oxygen). The solution was heated to 75° C for half an hour and then completely for approx. 100 parts water for precipitation of the polymeric phosphate. After washing the precipitate with water to remove excess phosphoric acid, the polymer was dissolved by heating to 50° C. in 15 parts water containing 1 part concentrated ammonium hydroxide. Dilute solutions (5% or lower) of this ammonium polyphosphate do not precipitate when acetic acid is added to pH 4.5. By evaporation of aqueous solutions of the ammonium salt, clear, colourless, hard, tough coatings are obtained. Addition of aqueous solutions of inorganic aluminum and calcium salts to the ammonium polyphosphate solution causes precipitation of aluminum and calcium polyphosphates.

Example 3:

A copolymer of glycidyl methacrylate and methyl methacrylate was prepared by heating 17.5 parts glycidyl methacrylate, 32.5 parts methyl methacrylate, 1 part alpha, alpha'-azodiisobutyronitrile and 120 parts acetone in a closed vessel for 16 hours at approx. 75° C with moderate stirring. Conversion of monomer to polymer was essentially 100%. The copolymer contained 35% polymerized glycidyl methacrylate, 65% polymerized methyl methacrylate and 3.94% oxyranoxygen.

The polymeric solution was diluted with acetone, so that it gave a solution containing 25 parts of polymeric solids and 100 parts of acetone. To this solution was added 21.23 parts of aqueous orthophosphoric acid (85.4% H3P04), which corresponds to approx. 3 mol phosphoric acid per oxirane oxygen. The resulting mixture was heated in a closed vessel for 1-y3 hours at approx. 60° C with moderate stirring. A clear solution of the phosphate of the epoxy copolymer was thus produced. The polymeric phosphate contained approximately 19.3% phosphate, calculated as - H 3 PO 4 , was precipitated by the addition of 500 parts of water. The precipitate was separated by filtration and was washed twice with 50 parts of water. The precipitate was then redissolved in acetone, precipitated again with water and filtered. About 1 part of the wet precipitate was added to 100 parts of 5% aqueous sodium hydroxide, and in a separate sample, to 100 parts of 5% aqueous ammonium hydroxide. It was soluble in both alkaline solutions. Although the resulting solutions were milky and not completely clear, they contained no filterable solids.

Example 4:

A copolymer of glycidyl methacrylate and butyl methacrylate was prepared by the method described in example 3, using 17.5 parts glycidyl methacrylate, 32.5 parts butyl methacrylate, 1 part alpha,alpha'-axodiisobutyronitrile and 150 parts acetone. The polymerization was substantially complete, yielding a copolymer containing 35% polymerized glycidyl methacrylate, 65% polymerized butyl methacrylate and 3.94% oxyranoxygen. This was treated as in example 3 with 14.15 parts of 85.4% phosphoric acid, corresponding to 1 mol of phosphoric acid per oxyran oxygen. The polymeric phosphate, isolated as in Example 3, was soluble in both 5% sodium hydroxide and 5% ammonium hydroxide. The solution was milky but contained no filterable solids.

Example 5:

840 parts were placed in a pressure vessel allyl glycidyl ether, 360 parts vinyl chloride and 43 parts alpha,alpha'-azodiisobutyronitrile. The vessel was heated to 80° C. for 16 hours, after which unreacted vinyl chloride was distilled off, and the remaining product was separated from unchanged allyl glycidyl ether by distillation at 130-170° C. at 0.25 to 0.04 mm mercury pressure. The polymeric epoxide produced in this way was a soft viscous material, containing 6.17% oxirane oxygen, which corresponded to 44% polymerized allyl glycidyl ether, and had a molecular weight of approx. 1600.

A solution of 40 parts of this polymeric epoxide in 160 parts of dioxane was added to 30 parts of 85% phosphoric acid (approx. 1.7 mol of phosphoric acid per oxirane oxygen) and the homogeneous solution was heated to 70-90° C for approx. 15 minutes. The polymeric phosphate formed was water soluble. It was precipitated by the addition of 10% aqueous sodium chloride and was washed free of excess phosphoric acid by repeated washings with 5% sodium chloride solution. The final product was water-soluble and its aqueous solutions could be treated with basic reagents, such as ammonia, amino or alkali metal hydroxides, so that it gave slightly acidic, neutral or basic solutions. Coatings, which were produced from aqueous solutions of this polymeric phosphate, were clear, hard, tough and adhered well to various substrates, such as metal or glass. Films of ammonium salt of this polymeric phosphate became insoluble in water when heated to 105-150°C.

Example 6:

A solution of 125 parts acrylonitrile, 125 parts allyl glycidyl ether and 15 parts di-tertiary butyl peroxide was added at a steady rate over a period of approx. 2 hours to 250 parts of allyl glycidyl ether, which was maintained at a temperature of 120 to 145° C. in a closed vessel. When everything had been added, boiling with a reflux condenser was continued at approx. 138° C for 1.5 hours. The polymerization mixture was freed from unchanged monomers by heating to 90° C under less than 1.0 mm of mercury pressure for approx. 4 hours. There remained 263 parts of a faintly colored, soft, glassy solid, which was soluble in acetone, dioxane, chloroform and cyclohexanone, but was insoluble in xylol, butylacetane and water. Based on recovered monomers, the copolymer contained approx. 54% by weight allyl glycidyl ether and 36% by weight acrylonitrile.

A solution of 3 parts of the above-mentioned copolymer dissolved in 12 parts of dioxane was added to 3 parts of 85% orthophosphoric acid (approx. 1.84 mol of phosphoric acid per oxirane oxygen). The solution was heated to 75°C for one hour. The product thus prepared was soluble in water, but coagulated from the aqueous solution on addition of sodium chloride. After washing three times with 5% aqueous sodium chloride, the remaining polymer was dissolved in water containing a small amount of ammonia. When evaporated onto glass plates, such aqueous solutions gave films which were clear, hard and tough, and had excellent adhesiveness.

Examples 7-12 explain the preparation of alkali-insoluble polyphosphates.

Example 7:

A copolymer of glycidyl methacrylate and methyl methacrylate was prepared by heating 15.0 parts glycidyl methacrylate monomer, 35.0 parts methyl methacrylate monomer and 1 part alpha,alpha'-azodiidobutyronitrile in 100 parts acetone in a closed vessel for 16 hours at approx. 75° C with moderate stirring. Conversion of monomer to polymer was essentially 100%. The copolymer contained 3.38% by weight of oxyranoxygen, which corresponded to 30% polymerized glycidyl methacrylate and 70% polymerized methyl methacrylate. 150 parts of the solution prepared above (containing 50 parts of epoxy copolymer) were added to 12.12 parts of aqueous orthophosphoric acid (85.4% H3PO4). The resulting mixture was heated in a closed vessel for 1-1/2 hours to approx. 60° C with moderate stirring. The amounts were equivalent to 1 mole of H 3 PO 4 for each mole of oxyranoxygen. A clear solution of the phosphate of the epoxy copolymer was thus produced. The polymeric phosphate, which contained about 17% phosphate calculated as - H 2 PO 4 , was precipitated by the addition of 500 cc of water. The precipitate was separated by filtration and was washed twice with each time 50 cm1 of water. The precipitate was then re-dissolved in acetone, re-precipitated with water and filtered. About 1 part of the thus prepared wet precipitate was added to 100 parts of a 5% ammonium hydroxide solution in water. The precipitate did not dissolve, even when stirred and heated to 80° C. for 5 minutes. The precipitate was likewise insoluble in 5% sodium hydroxide.

A clear coating composition was prepared in the form of a 30% solution of the copolymeric phosphate according to this example in acetone. A thin coating of this solution was poured onto a clean steel plate, which was then heated for 45 minutes at 138° C. A clear, hard film was formed, which protected the metal from rust.

A pigmented enamel was produced by grinding in a ball mill 125 parts of the copolymeric phosphate, 251 parts of methyl isobutyl ketone, 35 parts of butyl alcohol, 100 parts of ethylene glycol monoethyl ether acetate and 100 parts of titanium dioxide pigment until a uniform dispersion was obtained. The resulting enamel was sprayed onto a clean metal plate, which was baked for 30 minutes at 150° C. A durable, white glossy coating was formed, which protected the metal surface from rust. An enamel with these properties is useful for treating electrical equipment, outdoor furniture, and a large number of metal and ceramic articles. Although baking or curing at high temperatures improves the most useful properties of coatings made from the products of the present invention, such curing is not essential. The covers can be dried in the air and can therefore be used on surfaces that would not be able to withstand a large amount of heat, such as wood, organic substances and leather.

Example 8:

The procedure described in Example 7 was repeated except that the amount of glycidyl methacrylate monomer and methyl methacrylate monomer, the composition of the resulting copolymer and the amount of orthophosphoric acid were as follows:

The polymeric phosphates prepared in 8-A, 8-B and 8-C in the present example were insoluble in 5% ammonium hydroxide and 5% sodium hydroxide, as was the product of Example 7.

Example 9:

An ecoside copolymer, containing 35% polymerized glycidyl methacrylate, 65% polymerized methyl methacrylate and 3.94% oxyranoxygen, was prepared as indicated in Example 7 from 17.5 parts glycidyl methacrylate, 32.5 parts methyl methacrylate, 1 part alpha,alpha'-azodiisobutyronitrile and 120 parts acetone.

Treatment of the formed copolymer solution with 14.15 parts of 85.4% phosphoric acid (1 mol of H 3 PO 4 per mol of oxygen) by means of the method indicated in example 7 gave a gel system. This result seems to be due to too high a concentration of the copolymer solution.

Therefore, a less concentrated solution of the copolymer (25 parts copolymer solids, 225 parts acetone) was treated, using the procedure indicated in Example 7, with 5.65 parts 85.4% phosphoric acid. This corresponds to 0.8 mol of phosphoric acid per oxyran oxygen. A clear solution of the polymeric phosphate was formed. The polymeric material was isolated as in Example 7. About 1 part of the thus prepared wet precipitate was insoluble in 100 parts in both 5% aqueous ammonium hydroxide and 5% sodium hydroxide.

Example 10:

Phosphates and glycidyl methacrylate/butyl methacrylate copolymers were prepared using the method described in Example 7. The charge and composition of the products formed were as follows:

Both polymeric phosphate products of 10-A and 10-B in the present example were insoluble in both 5% aqueous ammonium hydroxide and 5% aqueous sodium hydroxide.

Example 11:

A copolymer of allyl glycidyl ether and methyl methacrylate was prepared as follows:

Portion was placed in a closed reaction vessel which was equipped with a stirrer, reflux cooler and thermometer and was heated to approx. 130° C. Portion B was then slowly added at a constant rate over a period of 3-y2 hours, while the temperature was maintained at approx. 130° C. After the entire portion of B had been added, the entire portion was held at this temperature for an additional 20 minutes. The unreacted monomers were then removed by distillation.

Approximately 50% of the starting monomers were thus converted into copolymer containing approximately 20% polymerized allyl glycidyl ether and 80% polymerized methyl methacrylate. The oxirane oxygen content of the copolymer was approximately 2.81%. The copolymer was dissolved in 750 parts of methyl ethyl ketone to give a clear solution containing 50% solids.

A polyphosphate of the above-described copolymer was prepared by reacting 750 parts of the 50% solution with 75.5 parts of aqueous 85.4% H3PO4 in 500 parts of acetone at 60-70°C for 1 hour with moderate stirring. The ratios of copolymer to phosphoric acid were equivalent to 1 mole of H 3 PO 4

for each mole of oxyran oxygen. A clear solution was formed in which the polymer

phosphate was contained approximately in an amount of 14.5% -H,PO4.

The polymeric material was separated by precipitation, filtration and washing as in Example 1. About 1 part of the wet precipitate was added to 100 parts each of 5% ammonium hydroxide and 5% sodium hydroxide and was found to be insoluble in both Media.

Example 12:

A copolymer of allyl glycidyl ether and vinyl chloride was prepared by reacting 630 parts of allyl glycidyl ether monomer, 1470 parts of vinyl chloride monomer and 21 parts of alpha,alpha'-azo-diisobutyronitrile in 922 parts of benzene in a stirred autoclave at approx. 60° C for 18 hours under a pressure of 4.3-5 kg/cm^. About 30% of the starting monomer was thus converted to a copolymer, which contained about 21% polymerized allyl glycidyl ether and about 79% polymerized vinyl chloride. The oxirane content in the copolymer was approximately 2.95%.

The polymeric material was separated by adding approximately 3 volumes of methyl alcohol for each volume of copolymer solution and filtering. The precipitate was dissolved in acetone, reprecipitated in methyl alcohol, filtered and dried.

A polyphosphate of the above-described copolymer was prepared by reacting 300 parts of solid copolymer with 61 parts of an aqueous 85.4% H.jPO., in 555 parts of acetone at 60-70° C. for 1 hour with moderate stirring. The ratios of copolymers to phosphoric acid were equivalent to 1 to H 3 PO 4 for each mole of oxyranoxygen. A clear solution was formed in which the polymeric phosphate contained approximately 15.2% - H 2 PO 4 .

A portion of the polymeric phosphate solution was evaporated to dryness at room temperature. One part of the dry material was stirred into 100 parts of 5% sodium hydroxide, but it did not dissolve. The solid was likewise insoluble in 5% ammonium hydroxide even at 60-70° C. Furthermore, when part of the acetone solution of the polymeric phosphate was added to a mixture of equal parts acetone and 5% sodium hydroxide, the solids precipitated substances insoluble in the medium.

Examples 13-16 explain the preparation of alkali-soluble polyphosphates from epoxy copolymers, in which the polymerized epoxy-free monomer contains acyloxy groups. It will be seen that alkali-soluble polyphosphates are also obtained when the oxyranoxygen content in the copolymer is very low.

Example 13:

A copolymer of allyl glycidyl ether and vinyl acetate was prepared by heating ti! refluxing a solution of 18 parts benzoyl peroxide in a mixture of 114 parts allyl glycidyl ether and 430 parts vinyl acetate. Once boiling under reflux was started, the heating was stopped and the solution was kept under reflux at the heat of the exothermic polymerization. Cooling was carried out to control the boiling and re- the race cooling. When the boiling finally stopped after approx. half an hour, heating was then applied gradually to maintain a solution temperature of 80-85° C. for one hour. The unchanged monomers were removed by distillation under pressure at 0.1-1 mm of mercury, the polymer being heated to 80-100° C. 437 parts of a polymeric epoxide were obtained, which has an oxirane oxygen content of 2.77%, corresponding to an oxirane equivalent weight of approx. . 577 and 20% polymerized allyl glycidyl ether.

A solution of 10.4 parts of this polymeric epoxide in 30 parts of dioxane was treated with 3 parts of 85% phosphoric acid (1.45 moles of phosphoric acid per oxyoxygen) and the mixture was heated to 0-85° C. for 20 minutes. The polymeric phosphate produced in this way is precipitated by the addition of water, but dissolves easily in dilute ammonium hydroxide. Such a solution had a viscosity of approx. 0.5 poise at 25% solids content. Evaporation of thin layers of this solution gave smooth, colorless, glossy, transparent, hard films, which had exceptionally good strength, adhesion and toughness. Curing by heating to 110-150° C gave insolubility.t.

The polymeric phosphate according to the present example was tested as a textile impregnating agent as follows: A 10% aqueous solution of the ammonium salt of the polymeric phosphate which was prepared as described above was prepared by adding in portions while stirring approx. 5 parts concentrated ammonium hydroxide to 1000 parts of an aqueous slurry, which contained 9.8% polyphosphate solids. The polyphosphate was dissolved, giving a clear colorless solution with pH 2.9, containing 10% polymer phosphate ammonium salt. This solution was applied to a 70 denier, 34 thread yarn of polyethylene terephthalate, and this yarn had a twist of 72 turns/2.5 cm, and the thus treated yarn was dried in a steam-heated cylinder. The treated yarn was then used on a standard loom to weave taffeta

135 warp threads per 2.5 cm and approx. 85 weft threads per 2.5 cm. After the loom has been kept running continuously for a period of 2 hours, no breakage or anything occurred

irregular in the warp. In tests on a larger scale, this and other polymeric phosphates, which were produced according to the present invention, showed excellent yarn protection and adhesion in cloth weaving, being clearly better than ordinary impregnating substances, such as gelatin, starch and various commercial synthetic preparations. trips.

Example 14:

A solution of 6.8 parts of benzoyl peroxide in a mixture of 205 parts of vinyl acetate, 22.8 parts of allyl glycidyl ether and 11.3 parts of isopropanol was heated to 75° C. At this point the heating was stopped, the solution being allowed to boil gently from the heat developed by the exothermic polymerization. The solution temperature during reflux cooling increased slowly over a period of approx. 1 hour at 87-89°C, while cooling was used from time to time to avoid too much boiling and too rapid rise in the solution temperature. After approx. For 2 hours, moderate heating was used to maintain a solution temperature of 85-87° C. At this stage, 11.3 parts of isopropanol were added, and heating was continued for one hour with a solution temperature of 85-87° C. An additional part of 22.6 isopropanol was added and the heating was increased, allowing the low-boiling fraction to distill off through a distillation column. The distillation continued for approx.

2 hours, as 48.1 parts were collected

the distillate. At this stage, the viscous residue contained 86.4% non-volatile solids. Analysis of a sample of this copolymer showed an oxyranoxygen content of 1.31%, which corresponds to 9.3% polymerized allyl glycidyl ether and a molecular weight of 3800.

260 parts of the 86.4% solution of polymer epoxy, as described above, was added at 40° C. to a solution of 200 parts of 85% phosphoric acid in 200 parts of isopropanol (9.3 mol of phosphoric acid per oxyranoxygen).

The reaction was thoroughly mixed while cooling to reduce the heat of reaction.

After allowing the mixture to stand for approx. 15 hours at 35-40° C, it was poured into six times the volume of water. The polymeric phosphate that precipitates was separated from the water by decantation and washed twice with water. A sample, purified by dissolving in acetone and precipitating in water, was dried by heating to 40° C. under reduced pressure of 0.1 mm of mercury. A potentiometric titration rather sharply showed inflection points at pH 4.4 and 10.2, on a graphic curve, where there was deposited alkali consumed in relation to the pH of the solution. The precipitated acidic polyphosphate was dissolved by adding approx. 560 parts water, which contained approx.

10 parts added concentrated ammonium hydroxide. A solution of the ammonium salt of this polymeric phosphate was thus prepared containing 19% solids and having a pH value of 5.85. In case of

evaporation of this solution, clear, colorless, hard moderately tough films were formed. These films adhere excellently to wood, paper, metals and plastic surfaces.

The good properties of polymeric phosphates in the treatment of leather were demonstrated in the following experiments: Chromium-tanned sheepskin, which had been washed free of chromium salts with water, was treated in a drum with approx. 3% by weight Neatsfoot oil emulsion at 50-55° C for half an hour. Sufficient of the 19% ammonium polyphosphate solution described above was then added to the drum to yield 45% by weight of the polymeric phosphate salt, based on the greater weight of sheepskin, and the drum treatment was continued for 1 hour at 52-55 ° C. The treated hides were drained to 100% relative humidity for 20 hours, late through rubber twisting rollers, so that excess moisture was removed and dried at 55 ° C for approx. 2 hours. The treated leather had a phosphorus content (calculated

as P205) of 1.2% compared to

0.5% for controls treated identically

with the exception that the polymeric phosphate treatment was not included. The polymeric phosphate-treated leather had excellent appearance and grip and could be easily polished

excellent peau-de-péche finish. Lower concentrations of polyphosphates, e.g. 5%

and 10% based on the dry weight of sheepskin, likewise gave a good filling effect.

In another experiment, tanned cowhide was brought to swell in dilute borax solution and treated with alum, followed by rinsing in water and by a treatment as above with the same 1% solution of ammonium polyphosphate, used in such an amount that approx. 15% polymeric solids based on dry weight of the leather. After drying, the treated leather was significantly improved, compared to the control sample, which had not been treated with the polyphosphate solution.

Example 15:

A solution containing 950 parts vinyl acetate, 50 parts allyl glycidyl ether. 150 parts of dioxane and 10 parts of benzoyl peroxide were heated with stirring to 73°C, at which temperature it refluxed. The heating was interrupted and the solution allowed to boil slowly under the developed heat of the exothermic polymerization reaction. After approx. 20 min. the solution temperature had reached 87° C. At this point, 150 parts of dioxane were added over a period of approx. 2 minutes, as the solution temperature was lowered to 89°C and foaming of the viscous solution was observed. By adding 79 parts of isopropanol, the foaming stopped, and

■ the solution temperature was lowered to approx. 80° C. The temperature began to rise again and a gentle heating was applied for a period of 1 hour to maintain a solution temperature of 80-95° C. At this point the solution contained 68% polymeric solids, which indicated about. 94% conversion of the monomers to copolymer. To this viscous mass was added 211 parts of dioxane. By heating with stirring, 100 parts of liquid containing 29.3% vinyl acetate were distilled off from the polymerization solution. The final solution of the copolymer contained 64% solids and had a viscosity of approx. 200 poise. The polymeric epoxide contained 0.62% oxyranoxygen, which corresponded to 4.4% polymerized allyl glycidyl ether, and it had a molecular weight of 7000.

To 781 parts of the above-described plumier epoxy solution, which contained 64% solids, was added a solution of 220 parts of 85% phosphoric acid in 220 parts of isopropanol (9.8 moles of phosphoric acid per oxiranic acid). The solution, which was heated spontaneously to 30-40° C., was heated to 85° C. and then allowed to stand for several hours. The polymeric phosphate was precipitated by pouring it into water, and it was washed thoroughly with water to remove excess phosphoric acid and solvents. This polymer was completely soluble in water upon addition of basic reagents, such as ammonia, amines, such as diethylamine, triethylamine, trimethylamine, isopropylamine, and ethanolamine, and alkali metal hydroxides, such as sodium and potassium hydroxide, and it was reprecipitated from such solutions by adding acid. The polyepoxide phosphoric acid reaction product had a neutralization equivalent of approx. 870 and contained 1.76% phosphorus. A solution of the ammonium salts of this polymer had a viscosity of 0.03 poise at 13% solids and a pH of 9.1. Films resulting from evaporation of this solution and air drying were colorless, clear and hard and had excellent toughness.

Example 16:

A mixture of 90 parts vinyl acetate, 10 parts 4-vinyl cyclohexane oxide (boiling point 50-52° C/8-9 mm) and 4 parts benzoyl peroxide was heated to boiling with reflux cooling (73-78° C) for approx. 3 hours. The highly viscous polymer ices ion mixture was dissolved in 200 parts of acetone, and the polymer was precipitated by the addition of cyclohexane. It was again dissolved in acetone and precipitated again by the addition of petroleum ether. The viscous resin was dissolved in a little benzene, and the solvents were then evaporated under reduced pressure at 1 to 0.1 mm of mercury with heating to 50° C. The colorless, brittle, solid polymer contained 0.74% oxyranoxygen, which was equivalent to 5, 7% 4-vinylcyclohexane oxide content.

A 15% solution of the above-mentioned copolymer in dioxane was added to an equal weight of a 15% solution of orthophosphoric acid in dioxane (approx. 18 mol. phosphoric acid per oxirane oxygen). The homogeneous clear composition was heated to 75-80° C. for 1 hour. By adding this solution to water, the insoluble polymeric phosphate precipitates. It was lightly washed with water to remove excess phosphoric acid. The purified product was readily soluble in dilute sodium hydroxide. Films prepared from such solutions by evaporation were clear, colorless, smooth, glossy and hard.

As starting material in the production of the polymeric phosphates according to the present invention, any polymeric epoxide can be used which is a copolymer of a polymerizable ethylenically unsaturated epoxy compound with a polymerizable ethylenically unsaturated acyclic compound, which is free of epoxy groups, and in which the weight ratio between polymerized epoxy compound and polymerized oxirane-free unsaturated substance is within the range of 3 : 97 to 60 : 40. Such copolymers offer a number of significant technical advantages in the production of polymeric phosphates. In the first place, it is possible with the help of these to obtain polymeric phosphates with a high molecular weight, and furthermore, the molecular weight can be regulated to a large extent as the starting copolymers are produced by free-radical initiated addition polymerization according to the methods that are well known to experts. Secondly, copolymers of the type mentioned above can be produced, in which a high molecular weight is combined with a large range of oxyranoxygen content, a combination that is not achieved with epoxy polymers produced by condensation reactions, such as epoxy-containing polymeric ethers. By properly choosing the weight ratio of the comonomer and polymerization conditions, it is possible to prepare copolymers containing various amounts of epoxy content up to the limit (60 percent by weight) which has been found desirable for such reasons as are explained below. Thirdly, the starting copolymers are usually easy to prepare by means of well-known methods, and in many cases offer the significant economic advantages as the mass can be derived from a cheap, readily available polymerizable monomer.

The specified limits for the weight ratio between polymerized components in starting polymers are critical. If there is significantly less than 3% polymerized epoxy compound based on the weight of total polymerized materials, there will not be sufficient epoxy groups present to react effectively with the phosphoric acid. On the other hand, if the polymerizable epoxy compounds are present in the polymerization mixture in such proportions that the copolymer formed has significantly more than 60% polymerized epoxy compound based on the total weight of polymerizable substances, the polymerization becomes difficult to carry out and control as unsaturated epoxy monomers does not polymerize very well. Furthermore, the financial benefits mentioned above are significantly reduced.

Another way of expressing the chemical composition of the suitable copolymers, from which the polymeric phosphates are produced, is in relation to the oxygen content. In order to produce polyphosphates having a phosphate content sufficient to impart significantly different properties, the polymeric epoxide must contain at least 0.3% by weight of oxyranoxygen. Preferably, the polymeric epoxide contains at least 0.6% by weight of oxyranoxygen. The upper limit of oxirane resource content, which is suitable to provide useful, economical polymeric phosphates, has been found to be approx. 8% by weight and preferably 7%.

Another way of expressing these numbers is in relation to the oxirane equivalent, i.e. the molecular weight corresponding to an atom of oxirane oxygen. It will be seen that 0.3% by weight of oxygen corresponds to an oxirane equivalent of approx. 5300, which is the upper limit for suitable polymeric epoxies. Preferably, the oxirane equivalent weight is less than 2500 for polyepoxides, which have molecular weights of about 500 to 7500. However, the properties of polyphosphates also depend on the composition of the epoxy polymer; as well as by its molecular weight. The molecular weight of the starting polymer epoxide is preferably within the range between approx. 1500 and approx. 10,000 but it can be as high as 50,000 or even higher. In general, if the molecular weight is high, it is preferred that the oxirane equivalent weight is low, e.g. 300 to 500. If the molecular weight is low, e.g. 1500-7000, the oxirane equivalent can be somewhat higher, e.g. between 1000 and

2500, depending on the composition of the copolymer. In general, the copolymer contains at least 1.5 epoxy groups per molecule.

The epoxy copolymers are produced using free radical-initiated polymerization according to known methods and with known free radical-producing starters. It is, of course, important to avoid conditions which would tend to open or otherwise destroy the ecopsy groups, such as the presence of strong; acids. To produce copolymers with the desired composition, the monomers are usually used in relative amounts within the range of 5 to 75 parts of oxirane-containing unsaturated for 95 to 25 parts of oxirane-free unsaturated. Two or more comonomers of each type can be used provided that the above conditions are observed.

A number of epoxy copolymers have been mentioned in the examples. Other suitable starting materials are copolymers of other ethylenically unsaturated epoxy compounds, such as butadiene monoepoxide, <1> glycidyl acrylate, vinyl glycidyl phthalate, allyl glycidyl maleate, allyl glycidyl phthalate, and the like with various acyclic vinylidene monomers, such as vinyl acetate, methyl acrylate, ethyl acrylate, methyl methacrylate, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, 1,3-butadiene, isoprene, 2-chloro-1,3-butadiene, vinyl chloride, vinyl fluoride, isopropenyl acetate, vinylidene chloride, methyl vinyl ether, acrolein, methyl vinyl ketone and the like.

The preferred copolymers are prepared from monomers having only one ethylenic carbon-to-carbon double bond to minimize the risk of cross-linking to insoluble materials. For the best results and maximum freedom from the side reaction during subsequent esterification, the copolymers must be free of groups other than epoxy groups, which easily react with phosphoric acid, such as amino, hydroxyl, mercapto groups and the like.

The preferred starting materials, because they provide the most generally useful polymeric phosphates, are copolymers of unsaturated epoxy compounds with polymerizable acyclic vinylidene compounds, i.e. acyclic compounds that have an end-methylene group attached by means of a double bond to the neighboring carbon atom. These preferred substances include copolymers of unsaturated epoxy compounds with the vinyl halides, e.g. vinyl chloride, vinyl fluoride, vinyl esters of monocarboxylic acid, e.g. vinyl acetate, vinyl propionate, acrylic and methacrylic acids, their esters, nitriles and amides, e.g. acrylic acid, methyl methacrylate, ethyl acrylate, acrylonitrile, methacrylonitrile, methacrylamide, monomethyl hydrocarbons which have a terminal ethylene double bond, e.g. isobutylene and the like. The preferred epoxy monomers are glycidyl methacrylate and allyl glycidyl ether.

The most useful starting materials, as they lead to alkali-insoluble polymeric phosphates and which have the best combination of properties, particularly with regard to use in coating compositions, are copolymers of glycidyl methacrylate with methacrylates of alkanols having one to four carbon atoms, e.g. methyl, ethyl, n-propyl and n-butyl methacrylates, such copolymers containing from 5 to 35% by weight of polymerized glycidyl methacrylate. Outstanding results are obtained with alkali-insoluble polymeric phosphates, derived from copolymers, containing from 15 to 25% by weight of polymerized glycidyl methacrylate and from 85 to 75% by weight of polymerized methacrylate of an alkanol of one to four carbon atoms, and most particularly methyl methacrylate. The preferred compounds according to the present invention are thus the alkali-insoluble polymeric phosphates obtained by the action of phosphoric acid on copolymers containing from 15 to 25% by weight polymerized glycidyl methacrylate and 85-75% polymerized methyl methacrylate. When these copolymers are substantially completely phosphatized by allowing them to react with one mole or more of phosphoric acid per oxy-oxygen, the calculated phosphate content, as - H2PO4, in the resulting phosphates is between 9.3 and 14.6%. Products, which are even more satisfactory when used as coating compositions, are obtained by partial phosphatisation of these copolymers, e.g. by allowing them to react with 0.6-0.9 mol of phosphoric acid per oxyran oxygen. The polyphosphates that can be hardened at lower baking temperatures than the essentially completely phosphatized products.

When alkali-soluble polymeric phosphates are desired, preferred starting materials are copolymers of allyl glycidyl ether and vinyl acetate, especially those containing between 3% and 50% by weight of polymerized allyl glycidyl ether. Another class of polymers leading to useful alkali-soluble polymeric phosphates are the copolymers of glycidyl methacrylate and methyl methacrylate, which contain from 35 to 50% by weight of polymerized glycidyl methacrylate.

As already indicated, it is important to use at least approx. half a mole of phosphoric acid per oxyranoxygen in the production of polymeric phosphates according to the present invention, as the use of smaller amounts tends to induce cross-linking and gelatinization and the polymeric epoxides. The upper limit is not critical as urea acid can easily be removed by washing out with water, and as much as 25 mol, or even more, of phosphoric acid can be used per oxyran oxygen. However, when alkali-insoluble polyphosphates are to be produced from copolymers containing more than approx. 3.9% oxyranoxygen, it is desirable to use less than 1 mol of phosphoric acid per oxyran oxygen. For the production of alkali-soluble polyphosphate, a satisfactory range for the ratios is between 1 and 10 mol phosphoric acid per oxyran oxygen. The optimum amount will vary to some extent in relation to the concentration of epoxy polymers in the reaction medium. With dilute solutions of epoxy polymers, e.g. resolutions of approx. 10% concentration

or lower, quantities of can be used

phosphoric acid as low as approx. half a mole per

oxy-oxygen with little risk of gelatinization. With more concentrated solutions of epoxy polymers, it is desirable to use at least 1 mol of phosphoric acid per oxirane oxygen, and with concentrations in the range 20-75% it is preferable to use from 4 to 15 mol of phosphoric acid per oxirane equivalent.

The preferred phosphoric acid is orthophosphoric acid as it is available at low cost and because it reacts easily, so that it gives uniform products, but other acids of phosphorus can be used, such as metaphosphoric and pyrophosphoric acids. Likewise, partially esterified phosphoric acids, such as methyl acid phosphate, can be used. or butyl acid phosphate.

In order to reduce the possibility of cross-linking of the polymeric epoxide to a minimum, the esterification reaction must be carried out in a solution of the polymer in an organic solvent, the solvent naturally having to be essentially inert towards the epoxide bonds and phosphoric acid. Such solvents are represented by the aromatic hydrocarbons, such as benzol, 1;oluol or xylenes, aliphatic or aromatic ketones, such as acetone, methyl ethyl ketone, cyclobutanone, acetophenone, acyclic or cyclic ethers, such as di-n-butyl ether, dioxane, tetrahydrofuran, diphenylene oxide, aliphatic alcohols, such as ethanol, n-butanol, isopropanol and the like. Preferably, the solvent is one which is miscible with water to permit the use of aqueous solutions of phosphoric acid. The polymeric solutions can be as diluted as desired, i.e. down to 1%'s concentration calculated by weight, but

it is generally unnecessary to use a concentration below 10%. Con-

the concentration can be as high as possible, e.g. up to 75%, a preferred range being 10 to 35% by weight.

The esterification reaction can take place at a practical rate at any temperature above 0° C and below 100° C. It proceeds rather slowly at temperatures up to 30° C and more rapidly at higher temperatures up to 100° C. A particularly useful range are temperatures between 50° to 85° C. Within this range, the reaction is generally substantially complete within a time period of one half to three hours. It is desirable to avoid long reaction periods and high temperatures. In other words, the conditions should be as mild as possible.

The reaction product, i.e. the polymeric phosphate is preferably isolated by adding sufficient water to the reaction mixture to precipitate the polymeric, or if the latter is water-soluble, an aqueous solution of a salt, such as sodium chloride, potassium sulfate, sodium phosphate, etc. The polymeric then washed with water or a saline solution to remove excess phosphoric acid. With the partially phosphatized substances, such a separation is not necessary. A coating composition can be prepared directly from the solution formed.

The polymeric esters of phosphoric acid thus produced are resinous substances, varying in consistency from viscous semi-solids to tough, moderately brittle, hard solids. Their molecular weight varies from approx. 1500 to approx. 50,000 or higher, but is usually within the range of approx. 2000 to approx. 10,000. These products are soluble in organic solvents, usually in the same solvents in which the polymeric epoxides are soluble.

As already discussed, some of the polymeric phosphates according to the present invention are soluble in dilute aqueous alkali, or also in water. Alkali solubility occurs when the calculated phosphate content is above approx. 19% by weight as - H2P04. with the exception of the polyphosphates derived from vinyl carboxylate/epoxy copolymers, which are alkali-soluble even at a much lower phosphate content. These highly phosphatized products are soluble in water, which contains sufficient alkali for partial or complete neutralization of the phosphoric acid groups. Such alkali can be an alkali metal hydroxide, e.g. sodium or potassium hydroxide, ammonia, or an alkylamine, preferably one containing 1 to 6 carbon atoms, such as methylamine, n-butylamine, diethylamine, triethylamine, ethanolamine, diethanolamine, cyclohexylamine and the like. These polymeric phosphates also form salts with other metals, such as copper, silver, zinc, aluminium, iron, nickel, cobalt, chromium or manganese. Some of these salts, such as zinc polyphosphates, are insoluble in water as neutralized salts, but are water-soluble as partially neutralized acid salts, and are also soluble in certain organic solvents. Other salts, such as the nickel and copper salts, are soluble in water when combined with an excess of ammonia. This is probably due to the formation of a metal-ammonium complex. The most useful of the salts are the water-soluble alkali metal ammonium or substituted ammonium salts, i.e. the amine salts and especially the ammonium salts.

However, the most important products according to the present invention are the polymeric phosphates which are insoluble in dilute aqueous alkali. These products generally have a calculated phosphate content of less than approx. 19% as - H2P04. A phosphate content of at least 1.75% and preferably 3% is desirable to impart useful improvements and significantly different properties to the polymeric phosphates compared to the copolymers from which they are derived, and the best properties are obtained when - the H 2 PO 4 content is in the range from 7 to 15%. These alkali-insoluble polyphosphates provide coatings that are harder, glossier and less sensitive to water and chemicals and more resistant to discoloration than the alkali-soluble polyphosphates.

The polymeric phosphates according to the present invention, and especially the alkali-insoluble ones, are particularly useful as ingredients for coating compositions, which may be clear or pigmented. Clear compositions can be prepared with any suitable organic solvent, such as acetone, methyl isobutyl ketone, n-butyl alcohol and the like. A large variety of pigments commonly used in organic coating compositions can be introduced, including titanium dioxide, carbon black, iron blue, phthalocyanine blue and green substances, metal oxides and chromates, organic browns, and various inert diluents, such as talc, baryte and kaolin. Other film-forming substances, which are miscible with the polyphosphates according to the present invention and which are soluble in the same solvents, can be mixed with the polyphosphate solutions so that they give clear or pigmented coating compositions. Examples of such film-forming substances are urine-formaldehyde resins, melamine-formaldehyde resins, alkyd resins and other natural and synthetic polymers.

Two other important uses of the products according to the present invention have also been described, these being the finishing of fibers of the polyester type, e.g. polyethylene terephthalate and treatment of leather. They have many other uses. For example, the already mentioned metal salts (e.g. copper or nickel), which can be water-solubilized using ammonia, can be applied to surfaces from aqueous solutions. On air drying, the remaining films develop ammonia and gradually become insoluble and not sensitive to water. Curing at elevated temperatures, e.g. 80—150° C, increases the insolubilization rate. Films or coatings of water-soluble polyphosphates, such as salts of aluminum or chromium, can be produced in situ by impregnating surfaces, such as paper, textile, wood, leather or ceramics with a water-soluble salt of these metals and a subsequent treatment of the impregnated surfaces with soluble ammonium or alkali metal polyphosphate. As an alternative, the surface can be impregnated first with the soluble polyphosphate and then treated with a suitable inorganic salt. This treatment forms insoluble metal poly-phosphate in the pores or fibers of the substrate. Coatings or films can thus be produced that have certain special properties, such as improved stiffness, increased stability and durability, increased flame resistance, etc.

Polyphosphate salts of metals, such as copper or mercury, have bactericidal and fungicidal properties and are useful as anchors and spreaders for insecticides, insect repellents, herbicidal compositions, and wood or textile preservatives.

Some of the polymeric phosphates according to the present invention adhere excellently due to their good tackiness and the high film strength which develops upon air-drying or curing at elevated temperatures. They are thus useful as adhesives for paper, textiles, wood, metal, plastic and other substances of a similar or different nature.

The water- or alkali-soluble polymeric phosphates according to the present invention are compatible to a considerable extent with colloidal silica sol, and such compositions are applicable in adhesives, finishes and in dispersed systems, such as polymeric dispersions and wax dispersions.

Aqueous solutions of ammonium, amine or alkali metal polyphosphates are useful as a clear varnish for wood, glass, ceramics, textiles, paper, metals and other substances and can be used either as a primer coating for the subsequent application of other varnishes or coatings, or as total protection or decorative finish for such fabrics. Salts such as cupric ammonium polyphosphates are particularly useful for sealing wood, textile and paper surfaces as the salt becomes insensitive to water upon drying and also imparts a preservative effect to such cellulosic material surfaces.

Aqueous solutions of soluble polyphosphates with low molecular weight show surface-like properties and can be used as dispersants in the production of oil or paint emulsions and in the polymerization of unsaturated compounds in aqueous systems. They are particularly useful as pigment dispersants and pigment binders in the production of water paints and pigment printing compositions. They are also useful as lime sequestering agents, cleaning agents and auxiliaries for the cleaning agent.

Claims (9)

1. Process for the production of polymeric phosphates, preferably suitable for coating compositions, where a phosphoric acid or partially esterified phosphoric acid is brought to react with a polymeric epoxy compound, characterized in that the polymeric epoxy compound is a copolymer of an ethylenically unsaturated epoxy-free compound and an acyclic ethylenically unsaturated epoxy-free compound, wherein said copolymer epoxy compound contains from 3 to 60% by weight of polymerized ethylenically unsaturated epoxy monomer and from 97 to 40% by weight of polymerized acyclic ethylenically unsaturated epoxy-free monomer, and the phosphoric acid or the partially esterified phosphoric acid is used in an amount of at least 0.5 mol per oxirane oxygen atom in the copolymer. 2. Method according to claim 1, characterized in that the ratio between phosphoric acid or partially esterified phosphoric acid and polymeric epoxide is such that a polymeric phosphate is formed, which contains unreacted epoxy groups. 3. Method according to claim 1 or 2, characterized in that the polymeric epoxy copolymer used has an epoxy oxygen content of from 0.6 to 8.0% by weight. 4. Process according to one of the preceding claims, characterized in that the copolymers are composed of monomers that have only one ethylenic carbon I to carbon double bond and are preferably free of other groups, such as ammonium, hydroxyl and mercapto groups, which easily react with phosphoric acid. 5. Method according to one of the preceding claims, characterized in that the copolymers used consist of unsaturated epoxy compounds and polymerizable acyclic vinylidene compounds. 6. Method according to claim 5, characterized in that the copolymers used consist of glycidyl methacrylate or allyl glycidyl ether and an acyclic vinylidene compound, especially with methacrylates of alkanols having from 1 to 4 carbon atoms, such as methyl methacrylate. 7. Method according to claim 6, characterized in that they used copoly more contains from 15 to 25% by weight of polymerized glycidyl methacrylate and from 85 to 75% of polymerized methyl methacrylate, the aforementioned copolymer preferably being brought to react with from 0.6 to 0.9 mol of phosphoric acid per oxyran oxygen. 8. Method according to claim 5, characterized in that the copolymer used is a copolymer of allyl glycidyl ether and vinyl acetate, and in particular one containing from 3 to 50% by weight of polymerized allyl glycidyl ether. 9. Method according to one of the preceding claims, characterized in that orthophosphoric acid is used.