DE1805182C3 - Coating agents - Google Patents

Description

consists.

2. Coating agent according to claim I, characterized in that linear polyesters are used are, for the preparation of which a mixture I has been used, the 60 to 40 mol percent consists of component 1.1 and 40 to 60 mol percent of component 1.2.

3. Coating agent according to Claim I and 2, characterized in that linear polyesters are used are, for the production of a (each object of the invention are coating agents based on a mixture of binders and organic solvents or water and that Additives that make water soluble in binders or, if necessary, on a solvent-free basis, as a binder

A. 50 to 10 percent by weight aminoplasts and / or their low molecular weight, defined precursors and

B. 50 to 90 percent by weight hydroxyl-containing and carboxyl-containing linear polyesters from ethylene glycol, propanediol (1,2) and optionally other diols on the one hand and aromatic and aliphatic dicarboxylic acids on the other hand

in addition to customary additives and auxiliaries, if applicable contain, the binder also by co-condensation of aminoplasts and / or their low molecular weight, defined precursors with the linear polyesters or by co-condensation of the starting products of the aminoplast production have been made with the linear polyesters can.

From the German Auslegeschrift 11 22 255 are unsaturated ethers of aminotriazine-formaldehyde condensates known to be either all such or but mixed with air-drying oils or other compounds polymerizable with peroxides such as styrene or unsaturated polyesters are used for the production of coatings, the Crosslinking by metal siccatives and possibly peroxides is required. From the British patent font 1000 534 is a special process for the production of unsaturated polyester known by Copolymerization with vinyl compounds, especially styrene, can be cured and thus also zui Production of coatings are suitable. The above

The means of pulling these fonts are based on other forms gang products and are networked according to completely different mechanisms.

From the USA patents 31 02 868 unc 31 08 083 are aqueous coating agents based on Aminoplasts and polyesters are known, the essential constituents of which are benzene tricarboxylic acids and the like also polyalkylene glycol monoalkyl ethers in addition to aliphatic dicarboxylic acids and aliphatic more

are valuable alcohols. These polyesters act : s are branched polyesters, which are also used in aqueous systems and -relatively expensive.

From the German Auslegeschriften 11 01 667 and 1231 833 are solvent-free coating agents Basis of aminoplasts known, which is obtained by using solutions of aminoplasts The usual plasticizers are added and the solvents are then removed by distillation in vacuo. Coating agents of this type have so far been able to be used - if only because of the difficulties involved in their production - do not enforce.

From the British patent 6 76 372 electrical insulating varnishes, especially wire enamels, based on polyesters from perephthalic acid, aliphatic dicarboxylic acids and ethylene glycol known, optionally with other synthetic or natural Resins, including aminoplast resins, can be combined. These polyesters must be have a molecular weight of 10,000 or more and are crystalline. Hence these become polyesters Dissolved in solvents such as phenols or cresols to form relatively dilute solutions, although the Wire enamelling common with normal sheet metal painting however, are undesirable.

From the German patent specification 1015165 it is known by curing a mixture of a phthalic acid - fumaric acid - propylene glycol - polyester on the one hand and a butylated meiamin-formaldehyde resin on the other hand to produce coatings.

The paint films obtained have a low chemical resistance.

From the German patent specification 1015 165 is still It is well known that coatings that are extremely chemically resistant are treated with a alkylated melamine-formaldehyde or urea-formaldehyde condensation product combined with a linear polyester made by polyesterification a dicarboxylic acid with a diol of the general formula

H- (OR) ₁ ,

-0- (RO) _n -H

is obtained in which A is a 2-alkylidene radical having 3 to 4 carbon atoms, R is an alkylene radical having 2 to 3 carbon atoms, m and η are each at least 1 and the sum of m and η is not greater than 3. It is also possible to use linear polyesters made from mixtures of such diols with one another or with smaller amounts of other dihydric alcohols. The coatings obtained from such coating agents are hard, but very brittle (see Comparative Example 1).

In the US ".- patent 2460186 polyesters from 2-ethylhexane-diol- {1,3) as a plasticizer of exceptional value for use in urea-formaldehyde or melamine-formaldehyde condensation products described. The coatings obtained according to this information are for Partly stretchable and impact-resistant, but too soft (see Comparative Example 2).

In addition, our own experiments show in which mixtures of linear polyesters and a melamine-formaldehyde resin were cured so that the coatings obtained are stretchable, but soft (see Comparative Examples 3 and 4).

The invention is based on the object of producing coatings in which there is a high degree of elasticity unite great hardness. In a number of older applications (P 1695 512.7, P1695 513.8, P1644 76L3, P 1644764.6, P 1644766.8, P 1644769.1)

Already suggested this task through use of polyesters or copolymers from very special starting materials.

This object has now been achieved, surprisingly, in that coating agents have been found

ίο where as component B linear polyester with average molecular weights between 600 and 3000 are used, which by esterification of the mixtures I and II have been prepared, mixture I

Ll to 70 to 30 mol percent from ethylene glycol and 1.2 to 30 to 70 mol percent from propanediol- (1,2)

consists, and optionally up to 30 mole percent of Total amount of components 1.1 and 1.2 by one or more other aliphatic e or cycloaliphatic floorboards in which the hydroxyl functions are separated by 2 to 8 carbon atoms and, if appropriate, oxygen atoms can be used instead of up to 2 of the carbon atoms, do again should be separated from one another by at least 2 carbon atoms, can be replaced, and Mixture II

11.1 from 91 to 33 mole percent of one or more cycloaliphatic dicarboxylic acids in which the carboxyl groups are in the 1,2- or 1,3-position

are arranged, or aromatic dicarboxylic acids and / or their derivatives and

11.2 to 9 to 67 mol percent of one or more aliphatic dicarboxylic acids having 4 to 12 carbon atoms and / or their derivatives

consists.

As diols to be used in minor amounts, in which the hydroxyl functions are replaced by 2 to 8 carbon atoms are separated and optionally up to 2 of the carbon atoms are separated by oxygen atoms can be replaced, which in turn should be separated from one another by at least 2 carbon atoms, e.g. propanediol- (ll, 3), butanediol- (1,2), Butanediol - (2,3), butanediol - (1,3), butanediol - (1,4),

4 <; 2,2 - dimethyl - propanediol - (1,3), Hxanediol- (1,6), 2-Ethylhexanediol, 3), Cyclohexanediol-O ^), Cyclohexanediol- (l, 4), 1,2-bis (hydroxymethyl) cyclohexane, 1,3 - bis (hydroxymethyl) - cyclolhexane, 1,4 - bis (hydroxymethyl) - cyclohexane, .x, 8 - bis (hydroxymethyl) -

_l ricyclo- [5,2,10 ^{2> 6} ] -decane, where χ stands for 3, 4 or 5, diethylene glycol, triethylene glycol, dipropylene glycol or tripropylene glycol. Cycloaliphatic diols can be used in their cis or trans form or as a mixture of both forms.

Aromatic or cycloaliphatic dicarboxylic acids are, for. B. phthalic acid, isophthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, hexahydroisophthalic acid as well as endomellethylene or endoethylene tetrahydrophthalic acid.

('0 len-tetrahydrophthalic acid or tetrabromophthalic acid suitable, the cycloaliphatic dicarboxylic acids in their trans or cis form or as a mixture both forms can be used. The use of dicarboxylic acids, in which the carb

Oxyigruppen arranged in 1,2-Siellung, especially phthalic acid and hexahydrophthalic acid, is preferred.
Particularly suitable aliphatic dicarboxylic acids are

other succinic acid, glutaric acid, adipic acid, suberic acid, Sebacic acid, decanedicarboxylic acid or 2,2,4-trimetbyladipic acid, However, unsaturated dicarboxylic acids, such as maleic acid, Fumaric acid: itaconic acid or citraconic acid, may be used, but the use becomes more saturated aliphatic dicarboxylic acids with 4 to 6 carbon atoms, in particular adipic acid or an approximately 1: 1 mixture of adipic acid and Succinic acid, preferred. ι ο

Instead of the free dicarboxylic acids, their esters with short-chain alkanols, e.g. B. dimethyl, Diethyl or dipropyl esters can be used. If the dicarboxylic acids form anhydrides, these can also be used, e.g. B. i "thalic anhydride, hexahydrop] liiha! Anhydride, tetrahydrophthalic anhydride, Succinic anhydride, glutaric anhydride or K maleic anhydride.

coatings with particularly good properties are obtained when using linear polyesters with average molecular weights between 1000 and 2500, which exclusively contain ethylene glycol and propanediol (1,2) as diol components and predominantly hydroxyl groups, & h. with a molar excess of diol.

The polyesters can be prepared by all known and customary processes, with or without a catalyst, with or without passing through a stream of inert gas, as solution condensation, melt condensation or azeotrope esterification, at temperatures of up to 250 ^° C. or higher, the water released or the liberated alkanols are continuously removed. The esterification is almost quantitative and can be followed by determining the hydroxyl and acid numbers. As a rule, the esterification conditions are chosen so that the reaction is as complete as possible, ie until the acid number in polyester batches composed of η mol of diol and (n-1) mol of dicarboxylic acid is less than 7 mg KOH / g.

With approaches from η mol diol and (n + l) mol dicarboxylic acid is esterified until the hydroxyl number is below 7 mg KOH / g. The molecular weight of the Polyester can be regulated in a simple manner via the use ratio of diol and dicarboxylic acid.

The esterification temperature is chosen so that the losses of volatile substances are low stay, d. i.e., at least during the first period of esterification, at one temperature esterified, which is below the boiling point of the lowest-boiling starting substance.

When producing the polyester, it should be noted that both the molecular weight of the polyester and the composition of which has an influence on the properties of the paint films produced from them. With higher mean molecular weights, the hardness of the paint film is usually reduced, while the elasticity increases, on the other hand the flexibility of the paint film leaves at lower molecular weights simultaneous increase in hardness. Differences in the composition also have a similar effect of polyester from: With a higher proportion of aliphatic dicarboxylic acids and with a larger proportion The length of the chain of the aliphatic dicarboxylic acids increases the elasticity of the paint film », while its hairiness <\ s is decreased. The opposite is the case with an increasing proportion of aromatic and / or cycloaliphatic Dicarboxylic acids in polyester make the paint film harder and

less flexible. The other diols which may be used also exert a similar influence As the chain length increases, these open-chain diols are used and the proportion increases These diols in the polyester make the paint film softer and more flexible. However, if you use the Her Position of the polyester additional diols with short and branched carbon chains or with cyclo aliphatic rings, the loading films made from these polyesters are usually too increasing proportion of these diols harder and less elastic. Knowing these rules is without it Difficulties are possible, within the scope of the claimed range polyester with for the respective purpose to select optimal properties and for the coating agents according to the invention to use.

The known reaction products of aldehydes, in particular, are suitable aminoplasts Formaldehyde, with several amino or amido-bearing substances, e.g. B. with melamine, Urea, dicyandiamide and benzoguanamine. Mixtures of these are also suitable Products. The aminoplasts modified with alcohols are particularly suitable.

Because of the sometimes only limited compatibility of these resinous products with those according to the invention Polyesters to be used are preferably the low molecular weight, defined precursors of aminoplasts, which are practically unlimitedly miscible with the polyesters to be used according to the invention, used. Such defined precursors of aminoplasts are e.g. B. tetramethylol benzoguanamine, trimethylol melamine or hexamethylolmelamine, which can also be used in partially or completely etherified form, e.g. B. as tetrakis- (methoxymethyl) -benzoguanamine, tetrakis- (ethoxymethyl) -benzoguananiine or polyethers of hexamethylolmelamine, such as hexamethoxymethylmelamine or Hexabutoxymethylmela min, can be used.

However, it is also possible to check the miscibility between the resinous aminoplasts and those according to the invention to improve the polyesters to be used and their compatibility during stoving, that certain amounts (up to 50 percent by weight, based on the total amount of solvent) of high-boiling polar solvents for both resins, such as B. ethyl glycol, ethyl glycol acetate, Butylglycol or cyclohexanone, or preferably polyester and aminoplast in known Way in substance or preferably in solution reacted with one another, whereby one to it has to ensure that the reaction does not progress to crosslinking. This can e.g. B. by short-term Heating the mixture or the joint solution of the two resins, optionally in the presence a catalyst, such as B. organic or mineral acids can be accomplished. It is also possible, the polyesters to be used according to the invention before or during the production of the Aminoplast resins from z. B. urea, benzoguanamine or melamine and aldehydes to add to the approach, it is of course also possible to additionally use customary alcohols to modify the plasticized amine plastic resins formed in this way are also to be used. The methods for producing such plasticized amine-aldehyde resins; both for Itt-

Both solvent-based and aqueous paint systems are known.

For combination with those used according to the invention Polyesters represent a large number of commercially available aminoplasts or their defined precursors available.

For the production of the coatings are usually initially polyester and aminoplast or their defined Precursors in common paint solvents, such as propanol, iso-propanol, butanol, ethyl acetate, Butylacetate, ethylglycol, ethylglycol acetate, Butyl glycol, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, trichlorethylene or mixtures of different such solvent, dissolved. It is of course also possible and for economic reasons For reasons it is advisable to use more or less large amounts of polar solvents, such as. B. benzene, Toluene, xylene or higher-boiling aromatic cuts, to be used. The amount of these less polar solvents used is within the range Solubility of the polyesters used according to the invention and their compatibility with the polyesters used Aminoplasts freely selectable; it can often have a proportion of up to 80% and more in the solvent mixture reach.

When using polyesters with a high acid number, i.e. with polyesters that have an even larger number have non-esterified carboxyl groups, it is of course also possible to use aqueous solutions to manufacture. This can be done according to the known and customary methods, usually the Carboxyl groups are completely or partially neutralized with amines and optionally also In addition, water-miscible solvents can also be used, which serve as solubilizers. Of course, in the production of aqueous lacquer solutions, water-soluble ones are necessary To use aminoplasts; the defined precursors of aminoplasts are also special for this purpose suitable.

The weight ratio polyester to aminoplast can be between 50:50 and 90:10, preferably between 65: 35 and 85:15, sway; for the respective purpose The optimal ratio of the paints can easily be determined by a few preliminary tests. It should be noted that often Increasing the aminoplast content increases the hardness of the paint films and reduces their elasticity is, while with a decrease in the aminoplast content the hardness decreases and the flexibility increases.

The total binder content of the paints can, depending on the intended use, be within the usual limits vary.

The lacquers can contain the usual additives and auxiliaries contain, for example, pigments, leveling agents and additional other binders, such as. B. Epoxy resins and silicone resins containing hydroxyl groups.

The varnish obtained is applied and fired at temperatures between 100 and 250 ⁰ C. The crosslinking reactions that take place in the process are catalytically accelerated by acids. When using polyesters with a very low acid number, acidic substances can therefore be added to the paint. When adding, for example, 0.5% p-toluenesulfonic acid (based on the total binder), the crosslinking is greatly accelerated. With the addition of larger amounts of slur, coatings that dry at room temperature can also be produced.

Also by reacting a low-acid polyester with about 1 to 5% of an anhydride of a relatively strongly acidic dicarboxylic acid, e.g. B. maleic anhydride, you can subsequently increase the acid number of the polyester and thus lower the stoving temperatures even without the addition of strongly acidic substances. The coatings produced according to the invention have an abundance of good properties. They are high-gloss, very easy to pigment and have excellent resistance to yellowing. If the coatings of a heat aging of 72 hours at 100 ⁰ C subjected, no visible yellowing is observed;

is also a heat aging of 72 hours at 150 ° C shows the coatings according to the invention to be resistant to yellowing. The coatings are permanent to solvents such as xylene, gasoline-benzene mixtures, esters and ketones. Dair beyond they have good acid and alkali resistance. For salt spray tests, tropical tests and tests in the weatherometer they show an excellent anti-corrosive effect and weather resistance.

The most outstanding property of the coatings produced according to the invention, however, is their greatness Elasticity with high hardness.

The elongation behavior of coatings is usually described by taking the Erichsen cupping test (according to DIN 53156) and the deepening of the lacquered as a measure of the elasticity Sheet in mm at which the paint layer begins to crack. Essential for this test procedure it is that the deformation of the coating is slow

takes place (feed: 0.2 mm / sec.).

The so-called impact depth measurement provides an indication of the behavior of coatings in the event of sudden deformation. This measurement can be carried out, for example, with the impact deepening device 226 / D from Erichsen, Hemer-Sundwig. With this device, a hemisphere with a radius of 10 mm is suddenly pressed into the sheet metal by a falling weight from the back of the paintwork. The depth can be varied by changing the height of the fall of the weight. The indentation value (in mm) at which the lacquer layer begins to tear is specified. (The values given in the examples were obtained in this way. In some examples, the value> 5 mm is given, since the device described does not allow a larger cupping with the 1 mm thick deep-drawn sheets usually used for testing.)
As stated in the description of the prior art and proven by comparative tests, coatings made of linear polyesters and aminoplasts are already known, which are stretchable and also withstand impact stress.
However, these coatings have a very low hardness (according to DIN 53157). On the other hand, coatings of high hardness are known, but they are not elastic. In contrast, the coatings obtained according to the invention have both high elasticity and great hardness.

This property profile opens up a wide range of applications for the coatings. In addition to the paintwork of individual parts that are exposed to impact stress, it is mainly the painting of

709 636/81

18 05 Ϊ82

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Materials to be considered subsequently - ζ. Β by punching - be deformed.

The polyesters used in accordance with the invention give low viscosity solutions. Leave it therefore paints with high solids content can be processed, which saves work steps can be exploited.

The following examples serve to further illustrate the invention:

Polyester production

A mixture of 192.2 g ethylene glycol (3.1 mol), 304 g propanediol-0.2) (4MoI), 592 g phthalic anhydride (4 mol), 1146 g adipic acid (1 mol) and 100 g succinic anhydride (1 mol) with stirring and passing a gentle stream of nitrogen according to the following heating time-temperature schedule: 2 hours at 140 ⁰ C, 2 hours at 160 ⁰ C, 4 hours at 180 ⁰ C, 4 hours at 19O ⁰ C and 16 hours at 200 ° C. During this time, a total of 122 g of water is separated out. The mixture is then stirred for a further 15 minutes at 20O ⁰ C and a vacuum of 20 torr. The clear, colorless resin has an acid number of 3: 2 mg KOH / g and a hydroxyl number of 79.9 mg KOH / g, which corresponds to an average molecular weight of 1,350. The polyester is dissolved in a mixture of 8 parts by weight of xylene, 1 part by weight of butanol and 1 part by weight of ethyl glycol acetate to form a 60% solution.

Increasing the acid number of a polyester

1.2% maleic anhydride (based on the pure polyester) is added to the melt of a polyester with a low acid number. After the added anhydride is completely dissolved, for 1 hour at 12O ⁰ C is heated, whereby the acid number of the polyester to 8.56 mg KOH / g is increased.

Increasing the acid number of a polyester will usually carried out in the melt, but there are no difficulties in the same reaction to be carried out in the solution of the polyester under the reaction conditions mentioned; it is included However, care should be taken that the solvent does not contain any functional groups that are under the mentioned reaction conditions can also react with the acid anhydride.

Manufacture of a lacquer

The solutions of the polyesters in suitable solvents, usually a mixture of xylene and a polar solvent, are mixed with a commercially available 55% solution of a melamine-formaldehyde condensate in a xylene-butanol mixture (1: 1) or with a commercially available hexamethylolmelamine derivative mixed in the desired solids ratio. In order to set a polyester-melamine resin ratio of 7: 3, for example 117 g of a 60% solution of the polyester are mixed with 54.5 g of the above-mentioned melamine resin solution; If polyester and melamine-formaldehyde condensate are not compatible with one another, the mixture of solutions - in the case of low-acid polyesters with the addition of 0.5% p-toluenesulfonic acid, based on the total amount of polyester and aminoplast - is 10 to 60 minutes 50 to 100 ⁰ C heated.

Manufacture of a paint color

To produce a lacquer color, a clear lacquer is pigmented _{with TiO 2 in a binder / pigment ratio of 2: 1.}

Manufacture and testing of coatings

For testing, the clear lacquer or the lacquer color is applied to test panels and glass plates and burned in. To lower the stoving temperature, lacquer solutions using made of polyesters with a low acid number, 0.5% p-toluenesulfonic acid (based on the

Total binder) added. The layer thickness of the films on which the test is carried out is in all of them Examples 40 to 60 µ. The hardness test is carried out in accordance with DIN 53 157, the elasticity test according to the methods described above.

Examples 1 to 8 are compiled in Table I, the type of melamine resin used is also specified. (In the column »Type of Melamine resin «means K that a butylated melamine-formaldehyde condensate was used, while HMM indicates the use of a hexamethylolmelamine derivative.) The: Table 2 contains the Test values for the coatings obtained from the polyesters described in Comparative Examples 1 to 4 below were manufactured.

Comparative example 1

1580 g of the symmetrical bis (hydroxyethyl) ether of bis-phenol-A (5 mol) are mixed with 400 g of amber

anhydride (4 moles) is heated by passing a stream of nitrogen for 6 hours at 18O ⁰ C. Remaining amounts of water of reaction are then removed by applying a vacuum of about 20 Torr. The polyester produced in this way has an acid number of 5 mg KOH / g; it is dissolved in a xylene-methyl ethyl ketone-cyclohexanone mixture (i: 1: 1) to form a 50 percent solution.

Comparative example 2
(Example 2 from U.S. Patent 2460186)

148 g phthalic anhydride, 146 g of adipic acid, 278 g 2-Athylhexandiol- (l, 3) and 110 ml of xylene are heated within 4 hours at 18O ⁰ C and further 4 hours at 200 ⁰ C, the water formed via a water separator is separated. The solvent is then slowly distilled off over the course of 4.5 hours, so that a temperature of 240 ^° C. is reached at the end.

Comparative example 3

(Example 1 from Ulimann's Encyclopedia

of technical chemistry, 3rd edition,
Vol. 14, p. 87, Urban & Schwarzenberg,

Munich-Berlin, 1963)

1400 g of adipic acid (9.6 mol) of ethylene glycol and 675 g (10.9 moles) are heated while passing a stream of nitrogen slowly to 130 to 140 ⁰ C. In order to ensure that no glycol is released when the reactor water is distilled off, part of the distillate is fed to the column as reflux. In the course of a few hours, the reaction

tion is heated mixture to 200 ⁰ C, then cooled to 150 ⁰ C and the condensation under vacuum continued until it at 200 Torr and 200 ° C ended after 5 to 8 hours. The waxy polyester has

a hydroxyl number of 54 mg KOH / g and an average molecular weight of 2000; it becomes in one Xylene-methyl ethyl ketone mixture (1: 1) dissolved to a 50 percent solution.

Comparative example 4

(Example 2 from Ullmann's Encyclopedia of Industrial Chemistry, 3rd Edition, Vol. 14, p. 87, Urban & Schwarzenberg, Munich-Berlin, 1963)

316 g of adipic acid (2.16 mole), 480 g of phthalic anhydride (3.24 mol) of ethylene glycol and 374 g (6.5 mol) are heated while passing a stream of nitrogen slowly to 160 to 200 ⁰ C, are passed through 118 g of distillate. Care must be taken that the transition temperature at the top of the column

Does not exceed 100 ° C. Then vrden at increasing vacuum in 6 hours still 19 g distilled off. The polyester has an acid number from 3 to 4 mg KOH / g and a hydroxyl number of 56 mg KOH / g; it is dissolved in a xylene-methylethylketone-cyclohexanone mixture (1: 1: 1) to form a 50% solution.

Table 1

example polyester Mitt Weight Type of catalyst Burn-in Hardness after Deep drawing Impact from [mol] leres ratio Melamine- conditions DIN 53157 capability deepening Mole Polyester too resin after Weight Melamine resin DIN 53156 ZuTiO ₂ [sec] [mm] [mm] 1 2 AG *) 680 70: 30: 0 HMM *) 0.5% pTS *) 130730 ' 135 8.8 4th 2PG *) 80: 20: 0 HMM 0.5% pTS 130730 ' 121 9.7 4-5 2PSA *) 80:20:50 HMM 0.5% pTS 130730 ' 128 7.2 3 - ^ * IADS *) 2 3ÄG 1270 70: 30: 0 HMM 0.5% pTS 140730 ' 161 > 10 > 5 3PG 80: 20: 0 HMM 0.5% pTS 140730 ' 149 > 10 > 5 3PSA 70:30:50 HMM 0.5% pTS 140730 ' 152 > 10 4-5 2ADS 80:20:50 HMM 0.5% pTS 140730 ' 138 > 10 5 3 4 AG 1430 70: 30: 0 HMM 0.5% pTS 140730 ' 178 > 10 > 5 4PG 80: 20: 0 HMM 0.5% pTS 140730 ' 164 > 10 > 5 5PSA 70: 30: 0 K *) 0.5% pTS 130730 ' 181 9.5 4-5 2ADS 80: 20: 0 K 1.2% MA *) 130730 ' 173 > 10 > 5 75:25:50 HMM 0.5% pTS 140730 ' 148 > 10 4 - ^ - 5 4th 3AG 2330 70: 30: 0 HMM 0.5% pTS 140730 ' 181 > 10 > 5 7PG 80: 20: 0 HMM 0.5% pTS 140730 ' 175 > 10 > 5 6PSA 80:20:50 HMM 0.5% pTS 140730 ' 159 > 10 4-5 1.5 OFF 1.5 BSA *) 5 4 AG 2810 70: 30: 0 HMM 0.5% pTS 140730 ' 178 > 10 > 5 9 PG 80: 20: 0 HMM 0.5% pTS 140730 ' 160 > 10 > 5 8PSA 80:20:50 HMM 0.5% pTS 140730 ' 145 > 10 > 5 2ADS 2BSA 6th 4 AG 1500 70: 30: 0 HMM 0.5% pTS 140730 ' 181 > 10 > 5 3PG 80: 20: 0 HMM 0.5%, pTS 140730 ' 176 > 10 > 5 4PSA 80: 20: 0 K 0.5%, pTS 130730 ' 179 8.8 4th 1 ADS 80:20:50 HMM 0.5%, pTS 140730 ' 153 > 10 > 5 IBSA 7th 3 AG 1350 70: 30: 0 HMM 0.5% pTS 140730 ' 192 > 10 > 5 4PG 80: 20: 0 HMM 0.5% pTS 140730 ' 184 > 10 > 5 4PSA 80:20:50 HMM 0.5% pTS 140730 ' 176 > 10 4th IADS IBSA

13th Mitt Weight * 18th 05 182 Λ 14th Deep drawing - Impact leres ratio U capability direction continuation Mole Polyester too Hardness after after Example polyester weighted t melamine resin Type of catalyst Burn-in DIN 53157 DIN 53156 from [Mo!] to TiO ₂ Mclamin building conditions resin [mm] [mm] 1670 70: 30: 0 > 10 4-5 80: 20: 0 [sec] > 10 > 5 80:20:50 173 9.9 3-4 8 4 AG HMM 0.5% pTS 140730 ' 165 4 PG HMM 0.5% pTS 140730 ' 148 1 DG *) HMM 0.5% pTS 140730 ' 6PSA 1 ADS IBSA *) Abbreviations: AG = ethylene glycol.

PG = propanediol-0.2). PSA = phthalic anhydride. ADS «adipic acid. HMM = hexamethylol melamine derivative.

K = melamine-formaldehyde condensate. pTS = p-toluenesulfonic acid. MA = maleic anhydride.

(The low-acid polyester is brought to a higher acid number by reaction with the specified amount of maleic anhydride - based on the pure polyester - using the method described.) BSA = succinic anhydride. DG = diethylene glycol.

Table 2

Ver Polyester Mitt Weight Type of catalyst Burn-in Hardness after Deep drawing Impact equal [Mole] leres ratio melamine conditions DlN 53157 tenacity ticfung example Mole Polyester too resins: after No. Weight Melamine resin DlN 53156 to TiQ ₂ [lake] [mm] [mm]

1 5 HABA *) 1880 70: 30: 0 K ·) 0.5% 4BSA *) 70: 30: 0 HMM *) 0.5%

2 1.91AHD *) 1750 70: 30: 0 K 0.5% IPSA *) 70: 30: 0 HMM 0.5% 1 ADS *)

3 10.9 AG *) 2000 70:30:50 K 9.6 ADS 70: 30: 0 HMM

4 6.5 AG 2050 70:30:50 K 3.24PSA 70: 30: 0 HMM 2.16 ADS

pTS 130730 '135

pTS 130730 '126

pTS 130730 '35

pTS 130730 '19th

pTS pTS

130730 ' 130730 '

130730 ' 130730 '

*) Abbreviations:

HABA = bis (hydroxyethyl) ether of bisphenol A. AHD BSA = succinic anhydride. PPE ■ K = melamine-formaldehyde condensate. ADS ■■

HMM = hexamethylol melamine derivative AG ■■

■■ 2-ethyl-hejcandiol- (1,3).
■ Phthalic anhydride ^: adipic acid. Ethylene glycol. '

45 39

25th 22nd

1.1 1.9

2.0

6.1 8.8

7.9 9.1

> 5

> 5> 5

> 5> 5

Example 9

The polyester of Example 1 is mixed at room temperature without the addition of solvent with a commercially available hexamethylolmelamine derivative (HMM) in which the required amount of p-toluenesulfonic acid is dissolved. From these mixtures clearcoat films are prepared μ with a wet film thickness of about 60 to 70 and baked for 30 minutes at 140 ⁰ C. Baked clear lacquer films from a mixture of 70 parts by weight polyester, 30 parts by weight share melamine derivative and 0.5 part by weight p-tolu <

sulfonic acid have a hardness of 107 seconds t

a depth of 10.7 mm and a sleep

deepening of 3 mm, while burned-in KIa

paint films from a mixture of 80 parts by weight

Polyester, 20 parts by weight melamine derivative ui

0.5 part by weight of p-toluenesulfonic acid in a shark

a deep drawability of 10.9 m in 102 seconds

and have a recess of> 5 mm.

After adding only 10 percent by weight of eth:

Glycol acetate for clear lacquer are stoved films obtained, the properties of which correspond to the films described in Example 1 completely. Be? pigmented lacquers, an addition of only 5 percent by weight of ethyl glycol acetate is sufficient to make films with to obtain the values given in Example 1.

Example 10

A mixture of 186 g of ethylene glycol (3 mol),> o 228 g of propanediol (1,2) (3 mol), 721.5 g of phthalic anhydride (4.875 mol) and 164.25 g of adipic acid (1.125 mol) is obtained until an acid number of 69.45 mg KOH / g with stirring and passing through a weak stream of nitrogen according to the following> 5 time-temperature plan: 2 hours at 140 ⁰ C, 2 hours at 160 ⁰ C, 4 hours at 180 ⁰ C, 4 hours at 19O ⁰ C and 8 hours at 200 ⁰ C. The clear, colorless resin has a hydroxyl value of 59.35 mg KOH / g; From the hydroxyl number and acid number, an average molecular weight of 870 is calculated.

174 g of this polyester resin (0.2 mole) are in 85 ° C with stirring with 20.2 g of triethylamine (0.2 mol). Then 74 g of isopropanol and * 5 then 80 g of water were added, resulting in a clear, colorless solution with a solids content of 50 percent by weight and a pH of 7.45. This solution, which can be kept unchanged for several months, can be used after adjusting the pH to 8.5 to 9 Water can be diluted as required.

This aqueous polyester solution and a commercially available hexamethylolmelamine derivative (HMM) are used to produce clear lacquers which are _{pigmented with TiO 2} in a binder / pigment ratio of 2: 1 and adjusted to a solids content of 60 percent by weight with water. The films prepared from this paint are baked for 30 minutes at 18O ⁰ C and are smooth and shiny. The stoved coatings, which contain a mixture of 70 parts by weight of polyester and 30 parts by weight of melamine derivative as a binder, have a hardness of 130 seconds, a deep-drawability of 9.4 mm and an impact indentation of 3 to 4 mm, while the coatings contain their binders 80 parts by weight of polyester and 20 parts by weight of melamine derivative, a hardness of 123 seconds, a deep drawing ability of 10.1 and an indentation of 3 mm own.

Example 11

A mixture of 99 g of ethylene glycol (1.6 mol), 266 g of propanediol (3.5 mol), 444 g of phthalic anhydride (3MoI), 109.5 g of adipic acid (0.75 mol) and 75 g of succinic anhydride (0 , 75 mol) is added under stirring and passing a gentle stream of nitrogen according to the following heating time-temperature schedule: 2 hours at 140 ⁰ C, 2 hours at 160 ° C, 4 hours at 180 ⁰ C, 4 hours at 190 ⁰ C and 42 5 hours at 200 ^° C. During this time, a total of 88 g of water are separated out. The clear, colorless resin has an acid number of 6.85 mg KOH'g and a hydroxyl number of 58.95 mg KOH / g, which corresponds to an average molecular weight of 1,710.

171 g of this polyester resin (0.1 mol) are ^{reacted in the melt at 150 °} C. with stirring with 28 g of phthalic anhydride (0.19 mol). After a reaction time of 4 hours, an acid number of 74.4 mg KOH / g is reached. The resin is cooled to 90 ° C and successively mixed with stirring with 20.2 g of triethylamine (0.2 mol), 69 g of isopropanol and 100 g of water, a clear solution with a solids content of 50 percent by weight, a pH of 7.2 and a lulling time of 48 seconds (DIN cup no. 6) results. After adjusting the pH to 8.5 to 9, this solution can be diluted with water as required.

From this aqueous polyester solution - as described in Example 10 - lacquer paints (binder / TiOj ratio 2: 1) with a solids content of 60 percent by weight were produced; the films produced from these paint colors are baked for 30 minutes at 18O ⁰ C. The stoved coatings, which contain a mixture of 70 parts by weight of polyester and 30 parts by weight of hexamethylolmelamine derivative (HMM) as a binding agent, have a hardness of 119 seconds, a deep-drawability of 10.2 mm and an impact indentation of> 5 mm, while the coatings, their Binder consists of 80 parts by weight of polyester and 20 parts by weight of melamine derivative, has a hardness of 126 seconds, a deep-drawability of 10.6 mm and an impact indentation of> 5 mm.

Claims (1)

Patent claims: 1. Coating agent based on a mixture of binders and organic solvents or water and the binder water-solubilizing additives or optionally also on a solvent-free basis, which acts as a binder A. 50 to 10 percent by weight aminoplasts and / or their low molecular weight, defined precursors and B. 50 to 90 percent by weight hydroxyl-containing and carboxyl-containing linear polyesters from ethylene glycol, propanediol (1,2) ' ⁵ and optionally other diols on the one hand and aromatic and aliphatic dicarboxylic acids on the other in addition to customary additives and auxiliaries, if applicable contain, the binder also by co-condensation of aminoplasts and / or their low molecular weight, defined precursors with the linear polyesters or by Mixed condensation of the starting products of the aminoplast production with the linear polyesters may have been made, characterized in that linear polyester with average molecular weights between 600 and 3 (KX) are used, which are obtained by esterification of the mixtures I and II have been produced, with Mixture I. 1.1 to 70 to 30 mol percent of ethylene glycol and 1.2 to 30 to 70 mole percent from propanediol- (1,2) consists, and optionally up to 30 mol percent of the total amount of components 1.1 and 1.2 by one or more other aliphatic ^ or cycloaliphatic diols in which the hydroxyl functions are separated by 2 to 8 carbon atoms and optionally in place of to to 2 of the carbon atoms can be oxygen atoms, which in turn are represented by at least 2 carbon atoms should be separated from each other, can be replaced, and Mixture II 11.1 at 91 to 33 mole percent. from one or more cycloaliphatic dicarboxylic acids in which the carboxyl groups are in the 1,2- or 1,3-position are arranged, or aromatic dicarboxylic acids and / or their derivatives and 11.2 to 9 to 67 mol percent of one or more aliphatic dicarboxylic acids with 4 to 12 carbon atoms and / or their derivatives Mix 11 has been used, which consists of 75 Us 50 mol percent of component II. 1 and 25 to 50 mol percent of component 11.2. 4. Coating agent according to Claim 1 to 3, characterized in that linear polyesters are used be, for the preparation of which a mixture I has been used in which up to 20 mole percent of the total amount of components 1.1 and 1.2 by one or more others Diols have been replaced. 5. coating agent according to claim 1 to 4, characterized in that linear polyesters are used are, for the preparation of which a mixture II has been used, the 75 to 67 mol percent of component II. 1 and 25 up to 33 mol percent consists of component II.2.