DE2356768B1 - Thermosetting coating agent - Google Patents

Description

Hexa etherified with 1 to 4 carbon atoms.

methylolmelamine derivatives. group-bearing polymerisation resins made of acrylic

Acid esters that are commercially available are suitable as the second binder component, saturated polyesters, oil-free or oil-modified alkyds are made according to known polymerization processes resins and / or acrylic resins containing hydroxyl groups 5 copolymers produced from acrylic acid esters, used. z. B. methyl methacrylate, ethyl methacrylate

Suitable saturated polyesters include condensers, methyl acrylates and higher alkyl esters from diols and / or polyols with acrylic and methacrylic acid with, for example, aromatic and / or cycloaliphatic dicarboxylic 2 to 12 carbon atoms in the alkyl ester group. acids and aliphatic dicarboxylic acids in question. io As further components in the copolymers As diols are ethylene glycol, propanediol (1,2), monoolefins or aromatic vinyl compounds propanediol - (1,3), butanediol (1,2), butanediol - (1,3), fertilize use. The butanediol (1,4), 2,2-dimethylpropanediol (l, 3), hexane hydroxyl groups necessary for crosslinking are converted into diol (l, 6), 2-ethylhexanediol (l, 3), cyclohexanediol with, for example, acrylic or methacrylic acid oxyol (1,2), cyclohexanediol (1,4), 1,2-bis (hydroxyethyl esters, methacrylic acid hydroxypropyl esters, momethyl) cyclohexane, 1,3-bis (hydroxymethyl) - cyclo- no- or dialkyl ethers of di- or polyglycols hexane, 1,4-bis- (hydroxymethyl) -cyclohexane, x, 8-bis- introduced. For the copolymerization, may continue (hydroxymethyl) -trizyclo- [5,2, l, 0 ² - ^6] decane, where χ for acrylamide or methacrylamide or their Formaldehyddie numerical values 3, 4 or 5, diethylene glycol, condensation products of acrylic or Methacrylic acid, triethylene glycol, dipropylene glycol or tripropylene maleic acid or maleic acid half-ester, styrene or glycol are suitable. Cycloaliphatic diols can serve in vinyl toluene,

their cis or trans form or as a mixture of both. The binder components are commercially available

Shapes are used. Products. Depending on the viscosity and miscibility,

As aromatic or cycloaliphatic dicarbons, they contain up to 60 percent by weight of a customary solution acid, phthalic acid, isophthalic acid and hexavalent agents. They are preferably solvent hydroterephthalic acid, Tetrahydrophthalic acid, processed hexa-free or low. In addition to liquid products hydrophthalic acid, hexahydroisophthalic acid and powdered products can also be used Endomethylene or endoethylene tetrahydrophthalic. In the latter case it will be the accelerator acid, hexachloro-endomethylene-tetrahydrophthalic acid mixed in as a powder.

or tetrabromophthalic acid in question, the cyclo- 30 The coating agents according to the invention can aliphatic dicarboxylic acids in their trans or in addition to pigments the usual HiKs and additives cis-form or used as a mixture of both forms contain, in particular leveling agent and gelewerden can. if necessary also other binders. the

Aliphatic dicarboxylic acids are suitable. Coating agents are applied by customary methods, such as stinic acid, glutaric acid, adipic acid, suberic acid, se- 35, for example brushing, spraying, dipping or bacic acid, decanedicarboxylic acid or 2,2,4-trimethyl rollers. Likewise, they can be converted into electroadipic acid. However, unsaturated static painting processes can also be used. After dicarboxylic acids such as maleic acid, fumaric bring the up they are at temperatures between marsäure, itaconic acid citraconic acid, branded used 100 and 250 ⁰ C.

will. 4 ° Have the coating compositions according to the invention

Instead of the free dicarboxylic acids, there can also be a number of surprising advantages. At the same time their esters with short-chain alkanols, z. B. Dimethyl, good effectiveness of the accelerator as in the diethyl or dipropyl ester, can be used. So far known, the dicarboxylic acids form anhydrides, the viscosity remains stable even after prolonged storage; this can be used immediately at Herauch, z. B. Phthalic anhydride, hexahydrophthalic anhydride, tetrahydride are used as the coating agent. Furthermore, the drophthalic anhydride, succinic anhydride and coatings produced from them tend to be less yellow.
Glutaric anhydride or maleic anhydride. As a special advantage it must be emphasized

Polyesters are used, the average of which is achieved by using the new accelerators Molecular weights are 250 to 4000. 50 becomes possible, environmentally friendly, i.e. H. solvent-

As oil-modified alkyd resins, there are low-conversion or free-conversion. Coating agents to use for electrostatic products of diols and / or polyols with aroma painting processes, since the electrical table or cycloaliphatic dicarboxylic acids, ali- resistance by these accelerators remains practically phatic dicarboxylic acids and saturated or unaffected. This can make the environmentally unsaturated fatty acids in question. As saturated and only recently known unsaturated fatty acids, caproic acid, excess caprylic acid, pelargonic acid, lauric acid, and myristic acid systems that have become solvent-free or low-solvent, are fully exploited,
acid, palmitic acid, stearic acid; Arachidic acid,
Eicosane carboxylic acid (l), behenic acid, oleic acid, linoleic acid

acid, linolenic acid and mixtures in the form of the 60 examples

Linseed oil, castor oil,

Ricin oil, tall oil, soybean oil, peanut oil or coconut oil production of polyester A

fatty acids. Synthetic fatty acids,

such as 2-ethylhexyl acid, a-alkyl carboxylic acids, iso- A mixture of 65.1 g of ethylene glycol (1.05 mol),

nonanoic acid, or synthetic fatty acid mixtures with 65 79.8 g propanediol (1,2) (1.05 mol), 74 g phthalic acid bis 9 carbon atoms are used. Of anhydride (0.5 mol) and 73 g of adipic acid (0.5 mol) In place of the free acids are also the esters and, with stirring and passing through, a weak one natural oils suitable. Nitrogen flow according to the following time-temperature

Schedule heated 2 hours at 140 ° C, .2 hours at 160 ⁰ C, 4 hours at 180 ⁰ C, 4 hours at 190 ° C and 4 hours at 200 ⁰ C. During this time, 25 ml of water are deposited in total. The clear, colorless ester mixture has an acid number of 2.5 mg KOH / g and a hydroxyl number of 454 mg KOH / g, which corresponds to an average molecular weight of 245.

Manufacture of polyester B

1296 gl, 4-bis (hydroxymethyl) cyclohexane (9 mol), 276 g glycerol (3MoI), 888 g phthalic anhydride (6 mol), 730 g adipic acid (5 mol) and 200 g xylene are circulated under nitrogen and continuous water 8 Heated to 200 ⁰ C hours. The resulting polyester has an acid number of 4.5 mg KOH / g and a hydroxyl number of 91.4 mg KOH / g. After cooling the melt to 140 ⁰ C, the polyester in xylene / dissolved to a 60 ° _o solution.

Manufacture of the catalyst 1

80 g of Versatic acid glycidate with an epoxy equivalent weight of 240 to 250 are under Stir with 20 g of p-toluenesulfonic acid monohydrate offset.

The mixture is stirred for 40 to 60 minutes. Then it is allowed to cool and diluted with 100 g xylene.

The solution prepared in this way contains 10% p-toluenesulfonic acid (calculated as the free acid).

Manufacture of the catalyst 2

50 g of a 10% strength p-toluenesulfonic acid solution in butyl glycol are added to 50 g of Versatic acid glycidate given and stirred at 50 to 60 ° C for 60 minutes. It is allowed to cool and a catalyst solution is obtained with 5% p-toluenesulfonic acid (calculated as free acid).

Manufacture of the catalyst 3

To 50 of a 80% strength ^E B g solution of a bisphenol A epoxy resin having the epoxy equivalent 225-280 in butyl glycol are 50 Geiner 10% igeH p-Toluolsulf onsäurelösung and stirred for 60 minutes at 50 to 6O ⁰ C in butyl glycol. It is allowed to cool and a catalyst solution containing 5% p-toluenesulfonic acid (calculated as the free acid) is obtained.

Manufacture of the catalyst 4

30 g of p-toluenesulfonic acid monohydrate are added to 150 g of an 80% solution of a bisphenol-A epoxy resin with an epoxy equivalent weight of 225 to 280. With stirring, the mixture was heated to 50 to 6O ⁰ C.

After the end of the reaction, which can be recognized by the drop in the reaction temperature after about 60 minutes, the mixture is diluted with 120 g of xylene. The catalyst solution obtained contains 10% p-toluenesulfonic acid (calculated as the free acid). ^;

Manufacture of the catalyst 5

To 200 g of a 50 ⁰ / "solution of a bisphenol AEpoxidharzes with the epoxide equivalent weight of 450 to 500 in xylene are added to 100 butylglycol Geiner 10 ° / _o by weight p-toluenesulfonic acid solution.

The mixture is heated with stirring at 50 to 6O ⁰ C for about 60 minutes. After cooling, a catalyst solution containing 3.3% p-toluenesulfonic acid (calculated as the free acid) is obtained.

Manufacture of the paint color

Polyester or commercially available alkyd resin were mixed with a commercially available hexakis-methoxy-methylmelamine derivative in a weight ratio of 7: 3. Optionally, both components for easier mixing are heated 10 to 60 minutes at 8O ⁰ C. The binder mixture obtained in this way is pigmented with titanium dioxide in a weight ratio of 1: 0.7.

The paint colors of the tests listed in the table below are catalyzed as follows (percent by weight, each based on the binding agent):

A. no catalyst,

B. 0.5% p-toluenesulfonic acid,

C. 2.35% of a 50% solution of the morpholinium salt of p-toluenesulfonic acid in ethyl glycol,

1. 0.5% p-toluenesulfonic acid in the form of catalyst 2 according to the invention,

2. 0.5% p-toluenesulfonic acid in the form of the invention Catalytic converter 3.

The viscosity of the paints was tested with a Haake viscometer, type VT180.

The electrical resistance of the paints was determined with the Randsburg measuring device, type 234-BA.

The measurements and storage of the samples took place at 23 ° C.

Table 1
Electrical resistance of the paints

55 resin 60 Polyester B 65 attempt Electric resistance Polyester A A. (kQ) B- 230 C. 35 1 25th 2 230 A. 220 B. > 20,000 C. 6000 1 1600 2 > 20,000 > 20O00

Table 2

Shelf life of the above paints with different catalysis

Ver
search Viscosity (cP) 4 months Resin component 24 h after after
Manufacturing A. Manufacturing 400 Polyester A B. 400 550 C. 350 600 1 500 370 2 300 350 A. 300 Polyester B B. 1000 C. 370 3500 1 690 300 2 280 250 230 Commercially available Al kydharz (containing 40% coconut oil), A. 7500 60 ° / _o in xylene ... B. 360 gelled C. 250 gelled 1 480 4500 2 250 1600 210 Commercially available Al kydharz (containing 40% ricin oil), A. 1700 60 ° / ₀ ig in xylene ... B. 410 gelled C. 330 gelled 1 500 700 2 380 350 220

409 582/402

Claims (2)

1 2 where in the adduct 0.1 to 1.0 claims per epoxy group: sulfonic acid groups are present. As sulfonic acids, aromatic, mono- 1. Thermosetting coating agent based on functionally sulfonic acids, for example benzenesulfone a mixture of binder and acid or their aliphatic or aromatic components of solvents and also given nucleus-substituted derivatives, such as o-, m- or p-toluene cases on a solvent-free basis, which is used as binding sulfonic acids, ethylbenzenesulfonic acid, naphthyl sulfonic acid Aminoplasts and / or their low molecular weight acid or their alkylated derivatives are used Cellular precursors can be mixed with saturated. Preferred are toluenesulfonic acids and Polyesters, oil-free or oil-modified alkyd ίο alkylbenzenesulfonic acids. Resins and / or acrylic containing hydroxyl groups. The second adduct components are aliphatic resins in addition to customary auxiliaries and / or aromatic epoxy resins - for example contains, characterized in that resins based on bisphenolA - or products it as a hardening accelerator 0.1 to 20 weight based on Versatic acid glycidate, glycidate, percent, based on the binder, of an ad- 15 epichlorohydrin, styrene epoxide, butadiene dioxide and / Products made from epoxy and monofunctional sulfone or epoxidized polybutadiene oils are used. Preferred acid, containing resins based on bisphenol A and in the adduct per epoxy group 0.1 to 1.0 sulfonic acid groups present Versatic acid glycidate. are. The production of the adduct takes place in the way, 2. Heat-curable coating agent according to An 20 that each of the two adduct components has a solution Claim 1, characterized in that it is produced as, both of which are then mixed. Cure accelerator an adduct of epoxy. Then it is 20 to 60 minutes long and monofunctional sulfonic acid, with 150 ° C, preferably 60 to 80 ° C, heated. the in the adduct per epoxy group, 0.4 to 0.5 sulf on adduct solution can be used directly. In acid groups are present. Another possible method is the adduct produced by mixing or fusing the two components at 20 to 150 ° C. The adduct can be used as such or in dissolved form medium mixture can be added. As a solvent 30 are aromatic hydrocarbons, alcohols, esters, ketones, glycol ethers or glycol ether esters or appropriate solvent mixtures are used. The present invention provides a thermosetting adduct in amounts of 0.1 to 20 Coating agent based on 35 percent by weight, based on the binder, in one Mixture of binder and proportions. As a measure of the necessary amount of Solvents as well as, if necessary, on solution adduct, the following applies that, based on the binder, medium-free basis, the aminoplasts as a binder 0.2 to 2 percent by weight, preferably 0.3 to 0.8 percent and / or their low molecular weight precursors in percent by weight of sulfonic acid in the binder mixed with saturated polyesters, oil-free or 40 is included. oil-modified alkyd resins and / or hydroxyl group- The coating agents to be crosslinked contain as pen-containing acrylic resins, in addition to customary binders, a mixture of two components. Contains excipients. One component are aminoplasts and / or To accelerate the crosslinking of the other low molecular weight precursors. As suitable led thermosetting coating agents 45 aminoplasts come the known implementation frequently acidic catalysts used. Such catalysis products of aldehydes, especially formaldehyde Sators can be inorganic acids, such as hydrochloric acid with several amino or amido groups and phosphoric acid, and organic acids, such as substances, in question, such as. B. with melamine, urinary toluenesulf onic acid, phenolsulfonic acid, maleic acid, substance, dicyandiamide and benzoguanamine. Suitable Fumaric acid, itaconic acid, citric acid or 50 are also mixtures of such products, their fissile salts. The addition of these additives are particularly suitable those modin accelerators with alcohols disadvantageously increases the viscosity of the decorated aminoplast. Storage and sets the electrical resistance of the case with a sometimes limited compatibility of these Coating agent strongly. Some salts of the resinous products with the second to be used Accelerators, in particular the morpholinium salts, 55 binder components will preferably have no effect although a limited improvement in the molecular, structure-defined aminoplasts that Storage stability, however, also lower that which can be mixed with it practically unlimitedly, one-electric Resistance and act on it sets. Such structure-defined aminoplasts are also disadvantageous due to stronger yellowing of the z. B. dimethylol urea, tetramethylol benzoguan thermoset Coatings. This results in 60 amine, trimethylol melamine or hexamethylol melamine special the extremely environmentally friendly, amine, which is also partially or completely etherified electrostatic painting process affected. Shape, e.g. B. as dimethoxymethylurea, tetrakis The object of the invention was to eliminate the (methoxymethyl) benzoguanamine, tetrakis (ethoxy disadvantages described) of the prior art to avoid. methyl) benzoguanamine or hexa-you polyether was solved in that the coating agent 65 methylolmelamine, such as hexakis (methoxymethyl) melals Cure accelerator 0.1 to 20 percent by weight, amine or hexakis (butoxymethyl) melamine, included on the binder, an adduct can be set. Are particularly preferred at Contains epoxy and monofunctional sulphonic acid, liquid in substance at room temperature, with alcohols