DE2848251A1 - Aqueous coating mixture containing phosphorous acid esters, process for their manufacture and their use - Google Patents

Description

-S-

patentanwälth, * 8 4 8 i b r

VIERING & JENTSCHURA

Authorized representative at the European Patent Office Dipl.-Ing. Hans-Martin Viering · Dipl.-Ing. Rolf Jentschura · Steinsdorfstrasse 6 · D-8000 Munich

Attorney File 3455 November 7, 1978

Hajtomüvek es Festöberendezesek Gyära, Budapest, HUNGARY

Aqueous coating mixture containing phosphoric acid esters, process for their preparation and their

use

_{II / W} 909819/0916

Stelnsdorfstrasse β Telex: S 212 306 jepa d Postscheck Munich 3067 26-801 D-8000 Munich 22 Telegram: Steinpat Munich Bayerische Vereinsbank Munich 567 995 Telephone: (0 89) 29 34 13 Fax: (0 89) 222 066 Raiffeisenbank Munich 032 18 18

(0 89) 29 34 14 (Siemens CCITT Norm Group 2) Deutsche Bank Munich 2 711 687

PATENT Attorneys ^ ° ⁴ °% ° '

VIERING & JENTSCHURA

Authorized representative at the European Patent Office Dipl.-Ing. Hans-Martin Viering · Dipl.-Ing. Rolf Jentschura · Steinsdorfstrasse 6 · D-8000 Munich

Attorney's file 34 55

Aqueous coating mixture containing phosphoric acid esters, Process for their preparation and their

Use.

The invention relates to that characterized in the claims Object.

It is known that as a result of the increasingly strict fire protection and environmental protection regulations in the past 10 years, the water-dilutable coating materials in constantly used in increasing quantities. One of the most common methods of using these coating materials is application by means of electrophoresis. However, this method is used - partly because it is expensive and complicated Applicator requires, on the other hand, because the coating materials are relatively large as auxiliary solvents Must contain glycol ether - limits are set.

It is also known that - if a metal surface with

_{II / W} 809819/0916 _ ₆ _

Steinsdorfstrasse β Telex: 5 212 306 jepa d Postscheck Munich 3067 26-801

D-8000 Munich 22 Telegram: Steinpat Munich Bayerische Vereinsbank Munich 567 895

Telephone: (0 89) 29 34 13 Fax: (0 89) 222 066 Haiffeisenbank Munich 032 18 18

(0 89) 29 3414 (Siemens CCITT Norm Group 2) Deutsche Bank Munich 2 711 687

the aqueous acidic solution of a dissolved, dispersed or emulsified film former comes into contact - in the Metal ions in the vicinity of the metal surface form in high concentrations, which are capable of absorbing the film-forming material in the Coagulate, flocculate or gel around the metal surface (British Patent No. 1,420,339). From the The essence of this process follows that the coating formed by the film former is deposited on the metal surface for so long how these and the acidic bath containing the film former are in contact with one another.

On the basis of this principle, any coating agent that is dissolved, dispersed or emulsified in water can be used as a coating former film-forming substance suitable that

(1) is stable in an acidic medium (pH 1-5),

(2) due to the action of the metal ions that form relatively quickly on the metal surface separates, and

(3) Forms a stable system even in the presence of the metal ions entering the bath, i.e. not coagulates, flocculates or gels.

It is obvious that the conditions (1) and (3) are mutually exclusive can be reconciled, but both of them are contrary to condition (2). Will the Conditions (1) and (3) are met, the separation

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28Α8 2'51 -sr-

that of the film former on the metal surface for a long time Claim, and also the thickness of the coating is insufficient. However, if a fast coagulating film former is used, so this is caused by the chemical deposition (hereinafter referred to as "chemophoresis") in the bath arriving metal ions are flocculated, coagulated or gelled.

A concrete solution based on the above principle is described, for example, in French patent specification No. 2 141 029. According to this process, strong oxidizing agents and iron (II) ions are converted into an aqueous styrene-butadiene latex introduced, and as a result, a relatively thick coating is deposited within a short time. Disadvantageous however, as a result of the rapid coagulation, the bath becomes unstable in a short time.

According to the aforementioned British Patent No. 1 4 20 339, the amount of metal ions entering the bath is determined regulated or kept at a value ensuring the stability of the bath by the bath for the purpose of removal the excess metal ions are treated with an ion exchange resin, preferably a cationic exchange resin will. The disadvantages of this method are that special measuring devices are used to determine the metal ion concentration are necessary and that the ion exchange resin must be constantly renewed or regenerated. In addition, it is proportionate long application time is disadvantageous.

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The aim of the invention is to overcome the disadvantages of the known chemophoretic Avoiding coating mixtures and developing an environmentally friendly coating mixture for metal surfaces, which on the one hand is stable in the bath used to form the coating, and on the other hand on metal surfaces forms a coating of sufficient thickness at sufficient speed.

It has now been found that this object can be achieved if a coating mixture based on an aqueous acid Solution, emulsion or dispersion of a film former 0.1-5% by weight, based on the weight of the solid film former, an acidic phosphoric acid ester of the general formula I.

OR-

I ³

R ₁ - CH - CH - O - P = O (I)

ι ι ι

OH R ₂ OH

adds, in which

R _{1 represents} a group of the general formula -CH ₅ -OR ₄ , in which R _{4 represents} an optionally substituted aliphatic, araliphatic or aryl group,

or R _{1 represents} a group of the general formula I) _n ~ in which R ₄

R.COO- (CH ₀ ) _-, in which R ^ the above meaning

90981 9/0916,

and η has the value O or 1, or R has the meaning of R.,
R _{2 stands} for an aliphatic group or for hydrogen

and

R- denotes hydrogen or a group of the general formula -CH-CH-CH-OR in which R and R R _{2 are} OH
have the preceding meaning.

As regards the mechanism of action of the acidic phosphoric acid esters of the general formula I, it can be assumed that at high metal ion concentrations, i.e. directly on the metal surface, they cause the deposition of the film former accelerate on this, with low metal ion concentrations, i.e. in the coating bath itself, however, a exert emulsifying effect. The acidic phosphoric acid esters of the general formula I are therefore surprisingly able to satisfy the aforementioned conditions (1) - (3) at the same time. As a result of their acidic character are the phosphoric acid esters of the general formula I participate in the pH adjustment of the coating bath. Through suitable Choice of the substituents R. and R- can be achieved that the phosphoric acid esters of the general formula I in the spatial crosslinking of the coatings formed by means of the coating mixture according to the invention, caused by the action of heat Participate in the film formation process and in this way - in complete contrast to the known and previously used

909819/09 16

Emulsifiers - do not worsen the protective properties of the finished coating, but even improve them.

The acidic phosphoric acid esters of the general formula I are known from Hungarian patent specification No. 162 217 and can be produced in the manner described there. For the sake of completeness it should be mentioned that in the procedure according to the above-mentioned Hungarian patent, the compounds of general formula I as additives for polycondensations are used and in the literature there is no indication whatsoever that they are in aqueous-acidic Medium exert an emulsifying, deposition accelerating or stabilizing effect.

The composition of the coating mixtures according to the invention is known per se without the addition of the acidic phosphoric acid esters of the general formula I. Except in the aqueous-acidic medium stable film formers, you can still use known dispersants, pigments, fillers, preservatives, Contains rust inhibitors, foam inhibitors, pH buffers, protective colloids, plasticizers, etc. The composition the coating mixtures used in each specific case depends, of course, on the intended use.

As a film former in the coating mixture according to the invention e.g. those described in British Patent Specification No. 1,420

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enumerated film formers, primarily synthetic resins or the latices prepared from these, can be used.

The coating mixtures according to the invention are in the sense of Invention prepared by adding to the aqueous solution, emulsion or dispersion of the film former before or after Addition of the usual additives 0.1-5% by weight, based on the weight of the solid film-forming agent, of an acidic phosphoric acid ester of the general formula I adds, the mixture obtained is homogenized in a manner known per se and the If desired, the pH is adjusted to a value between 1 and 5, preferably by adding phosphoric acid.

The coating mixes according to the invention are particularly suitable for the environmentally friendly and economically favorable coating of metal surfaces, e.g. when painting of motor vehicles.

The invention is explained in more detail below with the aid of examples.

example 1

192 g of dimethyl terephthalate are transesterified at 240 ⁰ C and 181 g of propylene glycol in the presence of 0.1 g of zinc naphthenate. 210 g of adipic acid,

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22 g maleic anhydride and 150 g dirtier is ierte fatty acid (Emery 3020, manufacturer: Unilever, Holland: iodine number: 25-35). The mixture is then ^{esterified at 210 °} C. until its acid number is 103 mg KOH / g. 148 g of 2-amino-2-hydroxymethyl-1,3-propanediol are then added to the mixture at 180 ^° C. Xylene is azeotropically distilled until the acid number has fallen below 2 mg KOH / g. A 75% solution is prepared from the residue with butyl glycol.

The solutions prepared in this way are added, based on the solid resin, to 0.2% by weight of isodecanoic acid monoglycerol ester monophosphate given. A 50% resin dispersion is prepared by adding water. After adding phosphoric acid the dispersion forms a clear, translucent solution at pH 1-5. The resin solution then becomes acid-resistant Dispersed pigment or acid-proof filler. The chemophoretically applicable coating material obtained forms diluted with water to a solids content of 15% stable system.

A coagulated from the coating material for 30 minutes stoved at 180 ⁰ C coating forms a hard, protective corrosion paint coat high elasticity.

9 09819/0916

Example 2

85 g of ethyl acrylate, 10 g of acrylic acid and 5 g of tert-butylaminoethyl methacrylate are in the form of a 60% solution in which the solvent is a mixture of isobutanol, isopropanol and butyl glycol prepared in a ratio of 1: 2: 2 Azodiisobutvlnitril the presence of a catalyst at 105 ⁰ C copolymerized. The copolymer obtained is reacted with the equivalent amount, based on its acid number, of a polyepoxy compound (Epon 828, manufacturer: Shell) until the acid number is zero. 3.2% by weight (based on the solid resin) of bis (phenoxyglycerol ester) phosphate are added to the copolymer solution obtained. Then, by adding water and phosphoric acid, a solution with a solids content of 40% and a pH of 2.5 is prepared.

Pigment is added to the resin solution obtained and a coating is formed from the chemophoretic coating material by coagulation. This is baked for 30 minutes at 120 to 150 ⁰ C and then gives a hard, corrosion-resistant coating.

Example 3

3 g of a condensate of oleyl alcohol and 30 mol of ethylene oxide (Nonion E 230; manufacturer: Nippon Oils and Fats Co., Ltd.,

909819/0916

Japan) and 5 g of polyvinyl alcohol are dissolved in 250 g of water. 20 g of a 25% strength aqueous potassium persulfate solution are added to a mixture of 80 g of butyl acrylate, 48 g of methyl methacrylate and 5 g of glycidyl methacrylate. The monomer mixture is then added dropwise at 75 ⁰ C within 4 hours into the above aqueous solution. To the fine, about 45% acrylate emulsion obtained by this emulsion polymerization, an acidic phosphoric acid ester, based on the solid resin, is added in an amount of 1.7% by weight, which according to Hungarian patent specification No. 162 217 from 1 Mole of glycidyl methacrylate, 1 mole of soybean oil fatty acid glycidyl ester and 1 mole of phosphoric acid.

From the acrylate emulsion stabilized with the acidic phosphoric acid ester, a chemophoretically applicable coating material of pH 2-4 is produced by adding phosphoric acid, a coating is made from the varnish obtained and this is ^{baked at 220 °} C. for 10 minutes. The coating obtained is very hard and has excellent chemical resistance.

Example 4

490 g of castor oil are reacted with 45 g of maleic anhydride at 200 ° C. The product obtained is in the presence of 5 g of cumyl hydroperoxide and 3 g of dodecyl mercaptan with a mixture

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copolymerized from 300 g Methyl-metiia.cryl.at and 55 q styrene. The copolymer obtained is in 900 g; Water dispersed. To the aqueous dispersion 36 g ( "d" i "to the weight of the copolymer based Gewv- 4% 1 an acidic Phosphorsäureesters given the ^z by reacting T Mbl n-butyl epoxystearate (Piiabrac C Manufacturer: Albright and Wilson Ltd. , England); acid was obtained with T mole of phosphorus The resulting dispersion is stable and suitable at pH 1-5 for preparing a crosslinkable at 180 ⁰ C within 15 minutes chemophoretischen Überzugsmaterxals..

Example 5

To 100 parts by weight of a styrene-butadiene copolymer (Pliolite 491; Manufacturer: Goodyear Rubber and Chemical Corporation, USA) is stirred vigorously, based on the amount of Solid resin in an amount of 0.75 wt .-%, an acidic phosphoric acid ester, prepared according to Example 4 became. The aqueous dispersion is stable in the pH range 1-5. Pigmenting turns it into a heat-curing, chemophoretically applicable coating material obtained, which has excellent water resistance and elasticity.

Θ09819 / 0916

Claims (1)

PATENT LAWYERS VIERING & JENTSCHURA authorized representatives at the European Patent Office / Dipl.-Ing. Hans-Martin Viering · Dipi.-Ing. Rolf Jentschura · Steinsdorfstrasse 6 · D-8000 Munich 22 Attorney File 3455 PATENT CLAIMS Coating mixtures with a pH value of 1-5 based on aqueous solutions, emulsions or dispersions of film-forming agents which are stable in the aqueous-acidic medium and which, in addition to the film-forming agent, also contain the usual additives contain, characterized in that, based on the solid film former, they contain 0.1-5% by weight of an acidic phosphoric acid ester of the general formula I contain, R ₁ - CH - CH - O - P = O (I) ¹ II I
- OH R ₂ OH in the R _{1 represents} a group of the general formula -CH ₇ -OR ₄ , in which R. represents an optionally substituted aliphatic, araliphatic or aryl group, 909819/0916 II / w -2- Stelnsdorfstrasse β Telex: 5 212 306 jepa d Postscheck Munich 3067 26-801 D-8O0O Munich 22 Telegram: Steinpat Munich Bayerische Vereinsbank Munich 567 895 Telephone: (0 89) 29 3413 Fax: (0 89) 222 066 Raiffeisenbank Munich 03218 18 (0 89) 29 3414 (Siemens CClTT Norm Group 2) Deutsche Bank Munich 2 711 687 or R _{1 represents} a group of the general formula R-COO- (CH _n ) -, in which R. the above meaning 4 2 η 4 has direction and η has the value 0 or 1, or R ₁ the Has meaning of R.,
R "stands for an aliphatic group or for hydrogen stands and
R- hydrogen or a group of the general formula -CH-CH-CH_-0R. means in the R_ and R. ι ι 2. 4 2. 4 R ₂ OH have the preceding meaning. 2. coating mixtures according to claim 1 _r characterized in that they respect the acidic organophosphate the general formula I in the solid film-forming agent an amount of 2-4 wt .-% by weight. 3. Coating mixtures according to Claims 1 and 2, characterized in that they contain a phosphoric acid ester of the general formula I in which R_ and R_ are hydrogen and R _{1 is} a group of the general formula R.COO-CH »- in which R. C00- means the acid residue of isodecylcarboxylic acid. 4. Coating mixtures according to Claims 1 and 2, characterized in that they contain a phosphoric acid ester of the general formula I, in which R_ is hydrogen and R _{1 is} a group of the formula -CH-OR. means, 90981 9 / 091S wherein R. is a phenyl group and R_ is a group of the general formula -CH-CH-CH - OR. I 1 ^{2 4} R ₂ OH means »in which the meanings of R_ and R. are given here is. ?:. Coating mixtures according to Claims 1 and 2, characterized in that they contain a phosphoric acid ester of the general formula I in which R_ denotes a hydrogen atom, R ₁ denotes a group of the general formula R.COO-CH--, where R. is a methacrylic group and R is a group of the general formula -CH-CH-CH ₂ -OR. R ₂ OH represents, in which R _{2 is} a hydrogen atom and R and R are the acyl radical which can be derived from the soybean oil fatty acid. 6. Coating mixtures according to Claims 1 and 2, characterized in that they contain a phosphoric acid ester of the general formula I in which R ₂ denotes an n-butyl radical and R ₁ denotes a group of the general formula R.C00- (CH _o ) - represents, in the R.COO- den from the 4 2 η 4 Stearic acid means acid radical derived and η has the value 0 and R_ represents a hydrogen atom. 7. Process for the preparation of the coating mixtures according to claim 1, characterized in that one adds to the aqueous solution, emulsion or dispersion of the film 309819/0918 In addition to the usual additives based on the weight of the film former, 0.1-5% by weight of an acidic phosphoric acid ester of the general formula I is added, in which R., R ₂ and R have the meaning given in claim 1, the mixture obtained in homogenized in a manner known per se and, if desired, the pH value adjusted to a value between 1 and 5 in a manner known per se. 8. The method according to claim 6, characterized in that the pH is adjusted by adding phosphoric acid. 9. Use of the coating mixtures according to claims 1 to 5 for coating metal surfaces. 909819/0918 -5-