DE1805183C3 - Coating agents - Google Patents

Description

and mixture II

11.1 to 100 to 70 mol percent of one or more aromatic or cycloaliphatic Dicarboxylic acids and / or their derivatives and

11.2 from 0 to 30 mole percent of one or more aliphatic dicarboxylic acids having 4 to 12 carbon atoms and / or their derivatives consists.

2. Coating agent according to claim 1, characterized in that linear polyester with average Molar weights between 600 and 2000 can be used.

3. Coating agent according to claim 1 and 2, characterized in that linear polyesters are used are, for their preparation as mixture I was used exclusively dipropylene glycol is.

4. Coating agent according to Claim 1 to 3, characterized in that linear polyesters are used only phthalic anhydride has been used as component II.1 for their production is.

The invention relates to liquid coating agents based on a mixture of binders and organic solvents or water and there; Binder solubilizing additives or given possibly on a solvent-free basis, the al; binder

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

B. 50 to 90 percent by weight of hydroxyl-containing and carboxyl-containing linear polyesters Diols on the one hand and aromatic and aliphatic dicarboxylic acids on the other

optionally in addition to the usual additives and auxiliaries contain, the binder also by co-condensation of aminoplasts and / or their low molecular weight defined precursors with the polyesters or by mixed condensation of the starting products Aminoplast production may have been made with the polyesters.

From DT-PS 10 15 165 it is known by curing a mixture of a phthalic acid-fumaric acid-propylene glycol polyester on the one hand and a butylated melamine-formaldehyde resin on the other Manufacture coatings. The paint films obtained have a low chemical resistance on. It is also known from this publication that one can use extremely chemically resistant materials Coatings are obtained when an alkylated melamine-formaldehyde or urea-formaldehyde condensation product is obtained combined with a linear polyester made by polyesterification of a dicarboxylic acid with a diol of the general formula

H- (0R) _m -0

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

is greater than 3. The coatings obtained in this way are hard, but very brittle (see Comparative Example 1). In US-PS 24 60 186 polyesters from 2-ethyl-hexanediol- (1,3) as plasticizers are exceptional Value for use in urea-formaldehyde or melamine-formaldehyde condensate

production products described. According to this information The coatings obtained are in part stretchable and impact-resistant, but too soft (see Comparative Example 2).

In addition, our own experiments show where

ho 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).

From Houben-Weyl. Methods of organic

ft.s Chemie (Vol. 14/2, pages 11, 22, 24 and 29) is the Production of linear mixed polyesters known. In addition, it is stated that these polyesters include i.a. With Aminoplasts can be crosslinked. A note

18 183

see or cycloaliphatic dicarboxylic acids and / or their derivatives and

! 1.2 to 0 to 30 mol percent, preferably to 5 to 15 mole percent, from one or more aliphatic dicarboxylic acids with 4 to 12 carbon atoms men and / or their derivatives.

As diols to be used in minor amounts, in which the hydroxyl functions are replaced by 2 to

that these products can be processed into paint raw materials is missing. In the same pamphlet (pages 337/338) shows that aminoplasts with polyesters made from adipic acid / polyol or with unsaturated Connections such as B. monoglycerides of native fatty acids, can be elasticized. The last mentioned Reaction products should also be used as coating agents. An indication of linear Polyesters - especially those of a certain composition - in connection with aminoplasts are separated as 10 8 carbon atoms and optionally The use of coating agents is not specified in this publication.

From the DT-PS 11 22 255 are unsaturated ethers of Aminotriazine / formaldehyde condensates known either as such or as a mixture 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 being due to Metal siccatives and possibly peroxides is accelerated.

DT-PS 14 94 500 describes as an older right coating agents made from acrylic polymer co-polymers and Aminoplast, which should contain up to 35 percent by weight alkyd resins. This is expressly pointed out (Column 1, line 18 ff.) That mixtures exclusively of alkyd resins and aminoplasts as coating agents have significant disadvantages, d. i.e., such mixtures are not claimed.

From US-PS 28 01 189, 29 31 739 and 32 07 623 linear polyesters are known, which, however, are not used in combination with aminoplasts. They are applied as such to glass fibers and are intended to serve as an adhesion promoter when the glass fibers are used as reinforcing material, e.g. B. in unsaturated polyester resins ,? S are used.

US-PS 33 92 135 describes the use of linear polyesters as plasticizers in crosslinked Polyvinyl halide resins. Nowhere in the pamphlet can it be inferred that this is here listed polyesters in connection with aminoplasts result in excellent coating agents.

The invention is based on the object of producing coatings in which high elasticity with great Unite hardness.

This object was surprisingly achieved in that the coating center! were found in which as Component B linear polyesters with average molecular weights between 300 and 2500 are used, the have been prepared by esterification of mixtures I and II, mixture I

1.1 to more than 70 to 100 mole percent, preferably to 80 to 100 mole percent, from dipropylene glycol and

1.2 to less than 30 to 0 mole percent, preferably to 20 to 0 mole percent, from one or more other aliphatic or cycloaliphatic Diols in which the hydroxyl functions are separated by 2 to 8 carbon atoms and optionally up to 2 of the carbon atoms can be replaced by oxygen atoms, which in turn should be separated from each other by at least 2 carbon atoms, consists,

and mixture ii

ILl at 100 to 70 mole percent, preferably 95 to 85 mole percent. from one or more aromatibis to 2 of the carbon atoms can be replaced by oxygen atoms, which in turn by at least 2 carbon atoms should be separated from each other, are suitable, for. B.

Ethylene glycol, propanediol- (1,2), propanediol- (U), butanediol- (U), butanediol- {2,3), butanediol- (1,3), butanediol- (1,4), 2,2- Dimethyl-propanediol- (1,3), hexanediol- (1,6), 2-ethylhexanediol- (1,3), cyclohexanediol- (1,2), cyclohexanediol- (1,4), l, 2-bis- (hydroxymethyl) cyclohexane, 1,3-bis (hydroxymethyl) cyclohexane, 1,4-bis (hydroxymethyl) cyclohexane, x, 8-bis (hydroxymethyl) tricyclo- [5.2, 1.0 ² - decane ^6], wherein χ is 3, 4 or 5, diethylene glycol, triethylene 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,
Hexahydroterephthalic acid,
Tetrahydrophthalic acid, hexahydrophthalic acid, hexahydroisophthalic acid and endomethylene or endoethyl-tetrahydrophthalic acid, hexachloro-endomethylene-tetrahydrophthalic acid or tetrabromophthalic acid

suitable, the cycloaliphatic dicarboxylic acids in their trans or cis form or as a mixture of both Shapes can be used. The use of phthalic acid, isophthalic acid and hexahydrophthalic acid is preferred.

Succinic acid, glutaric acid, adipic acid, suberic acid are particularly suitable as aliphatic dicarboxylic acids, Sebacic acid, decanedicarboxylic acid or 2,2,4-trimethyladipic acid. The use of aliphatic dicarboxylic acids with 4 to 6 carbon atoms, especially adipic acid, is preferred.

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.
Phthalic anhydride,
Hexahydrophthalic anhydride, tetrahydrophthalic anhydride,

Succinic anhydride or glutaric anhydride.

Receives coatings with particularly good properties

when using linear polyesters with

average molecular weights from 600 to 2000, in particular

from 800 to 1500, predominantly hydroxyl groups

contain, d. H. with a molar excess of diol have been manufactured.

The polyesters can be produced by all known and customary processes, with or without Catalyst, with or without reading through an inert gas stream, as solution condensation, melt condensation or azeotrope esterification, at temperatures up to at 250 ° C or higher, whereby the

Water released or the alkanols released 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 10 mg "'OH / g η mol of diol and (n + 1) mol of dicarboxylic acid are esterified until the ι o hydroxyl number is below 10 mgKOH / 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 remain low, d. i.e., at least during the first period of esterification, esterification is carried out at a temperature which is below the boiling point of the lowest-boiling starting substance.

When manufacturing the polyester it should be noted that Both the molecular weight of the polyester and its composition influence the properties of the paint films made from them. In the case of higher average molecular weights, the hardness of the Lacquer film decreases while the elasticity increases, on the other hand leaves the flexibility at lower molecular weights of the paint film with a simultaneous increase in hardness. Differences also have a similar effect in the composition of the polyester from: With a higher proportion of aliphatic dicarboxylic acids and with a larger chain length of the aliphatic dicarboxylic acids, the elasticity of the paint film increases, while its hardness is reduced. 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. A similar influence exercise the other diols that may also be used: with increasing chain length these concomitantly used open-chain diols and with increasing proportion of these diols in the polyester is the Paint film softer and more flexible. However, if diols are also used in the production of the polyester short and branched carbon chains or with cycloaliphatic rings are what these are made of As a rule, the higher the proportion of these diols, the harder and harder the polyesters produced less elastic. With knowledge of these rules it is possible without difficulty within the scope of the claimed Select a range of polyester with optimal properties for the respective application and to be used for the coating compositions according to the invention.

The known reaction products of aldehydes, in particular, are suitable aminoplasts Formaldehyde, with several amino or amido-bearing substances in question, such as. B. with Melamine, urea, dicyandiamide and benzoguanamine. Those modified with alcohols are particularly suitable Aminoplasts.

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, those to be used with the foundations Polyesters are practically infinitely miscible, are used. Such defined precursors of aminoplasts are z. B. tetramethylol benzoguanamine, trimethylol melamine or hexamelhylol melamine. which are also partially or fully approximated, e.g. as Tetrakis- {methoxymethyl) -benzoguanamm, TetrakisfäthoxymethyO-benzoguanamJn or polyethers of hexamethylol melamine, such as hexamethoxymethyl melamine or hexabutoxymethylmelamine can be used. .

However, it is also possible to improve the miscibility between the resinous aminoplasts and the polyesters to be used according to the invention, as well as their compatibility during stoving, by adding certain amounts (up to 50 percent by weight based on the total amount of solvent) to the mixture of solutions of polyester and aminoplast ) on high-boiling polar solvents for both resins, such as ζ B ethyl glycol, ethyl glycol acetate, butyl glycol or cyclohexanone, or preferably polyester and aminoplast in a known manner reacts in bulk or preferably in solution, whereby care must be taken that the reaction does not until networking progresses. This can e.g. B. by briefly heating the mixture or the common solution of the two resins, optionally in the presence of a catalyst, such as. B. organic or mineral acids can be accomplished. It is also possible to use the polyester to be used according to the invention before or during the preparation of the aminoplast resins from z. B. urea, benzoguanamine or melamine and aldehydes to be added to the batch, whereby it is of course also possible to also use customary alcohols for modifying the plasticized aminoplast resins thus formed. The methods for producing such plasticized amine-aldehyde resins both for solvent-based and for aqueous paint systems are known.

A large number of commercially available polyesters are available for combination with the polyesters used according to the invention Aminoplasts or their defined precursors are available.

For the production of the coatings are usually initially polyester and aminoplast or their defined precursors in conventional paint solvents such as for example propanol, isopropanol, butanol, ethyl acetate, Butyl acetate, ethyl glycol, ethyl glycol acetate, butyl glycol, methyl ethyl ketone, methyl isobutyl ketone Cyclohexanone, trichlorethylene or mixtures of various such solvents, dissolved. It is of course also possible and recommended for economic reasons, more or less large amounts of less polar solvents, such as ζ. Β Benzene, toluene, xylene or higher-boiling aromatic cuts, to be used. The amount of these less polar solvents used is within the range the 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 middle of the solution get mixed.

When using polyesters with a high acid number d. H. in the case of polyesters, which do not have a larger number have esterified carboxyl groups, it is of course also possible to prepare aqueous solutions This can be done according to the known and customary methoder, the carboxyl groups as a rule be completely or partially neutralized with amines and optionally additionally with water Miscible solvents are also used, which serve as solubilizers. Of course it is with you

Preparation of aqueous paint solutions required to use water-soluble aminoplasts; the Defined precursors of the aminoplasts are also particularly suitable for this purpose.

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

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

The paints can contain the usual additives and auxiliaries, 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 baked at temperatures between 100 and 250 ° C. The crosslinking reactions that take place are catalytically accelerated by acids. Using Acid substances can therefore be added to the coating of polyesters with a very low acid number. When adding, for example, 0.5% p-toluenesultonic acid (based on the total binder) the crosslinking is greatly accelerated. Due to the addition of a larger amount of acid coatings that dry at room temperature can also be produced.

Even by reacting a low-acid polyester with about 1 to 5% of an anhydride a relatively strong one acidic dicarboxylic acid, e.g. B. maleic anhydride, you can increase the acid number of the polyester later 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 are subjected to heat aging for 72 hours at 100 ^° C., no visible yellowing can be detected; Heat aging of 72 hours at 150 ° C. also shows that the coatings according to the invention are resistant to yellowing. The coatings are resistant to solvents such as xylene, gasoline-benzene mixtures, esters and ketones. In addition, they have good acid and alkali resistance. In sprinkling tests, tropical tests and tests in the water heater, they show an excellent anti-corrosion effect and weather resistance.

The henuisragendstc property of the foundational produced coatings, however, is their great elasticity with high hardness.

The elongation behavior of coatings is usually described in terms of the Erichscn-test (according to DIN 53 156) and as a measure of the extensibility, the deepening of the painted sheet metal in mm indicates at which the gap layer begins to tear. It is essential for this test procedure that the deformation of the coating takes place slowly (feed: 0.2 mm / scc).

The provides a starting point for the behavior of coatings in the event of sudden deformation so-called impact deepening measurement. This measurement can be carried out, for example, with the impact test device 226 / D by the company Erichsen, Hemer-Sundwig. This device uses a hemisphere a radius of 10 mm due to a falling weight from the back of the paint into the sheet metal depressed. The depth can be varied by changing the height of the fall of the weight. It will be the Indentation value (in mm) indicated at which the lacquer layer begins to tear. (The ones in the examples values given were obtained in this way.

ίο In some examples, the value is > 5 mm specified, since the device described does not have any with the 1 mm thick deep-drawn sheets usually used for testing larger cupping possible).

As stated in the description of the state of the art and proven by comparative tests is, coatings made of linear polyesters and aminoplasts are already known, which are stretchable and also one Withstand impact stress. However, these coatings have a very low hardness (according to DIN 53 157).

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 uses for the coatings. In addition to painting Individual parts that are exposed to impact stress are mainly the paintwork of materials into consideration, the retrospectively - z. B. 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.

Polyester production

A mixture of 616.4 g of dipropylene glycol (4.6 mol) and 592 g of phthalic anhydride (4 mol) is heated with stirring and passing through a gentle stream of nitrogen according to the following time-temperature plan: 2 hours at 160 ^° C., 2 hours at 180 ⁰ C. for 36 hours at 200 ⁰ C and 8 hours at 22O ⁰ C. during this time a total deposited 67 g of water. Subsequently, further 20 minutes at 22O ⁰ C and a vacuum of 20 Torr is stirred. The clear, pale yellow colored resin has an acid number of 5.5 mg KOH / g and a hydroxyl number of 46.3 mg KOH / g, which corresponds to an average molecular weight of 2160. The polyester is dissolved in xylene to give a 60% solution.

Increasing the acid number of a polyester

1.2% maleic anhydride (based on: iuf dci pure polyester). After that added! Anhydride is completely dissolved, 1 hour at 120 "C heated, whereby the Siiurczahl the polyester un 8.56 mg KOH / g is increased.

The increase in the acid content of a polyester is ii usually carried out in the melt, jcclocl there are no difficulties, the same reaction ii the solution of the polyester under the conditions of reaction; it is dabc (I should, however, be careful not to use the solvent Functional groups revealed under the gcnnnntci Conditions of interaction also with the Siiiircanhy clrid can react.

10

Manufacture of a lacquer

The solutions of the polyester in suitable solvents, usually a mixture of xylene and a polar solvent, with a commercially available 55 percent solution of a melamine-formaldehyde condensate in xylene-butanol mixture (1: 1) or with a commercially available hexamethylolmelamine derivative im desired solids ratio mixed. To set a polyester: melamine resin ratio of 7: 3, For example, 117 g of a 60 percent solution of the polyester with 54.5 g of the above Mixed melamine solution; polyester and melamine-formaldehyde condensate should not interfere with each other be compatible, the mixture of the solutions - in the case of low-acid polyesters with an addition of 0.5% p-toluenesulfonic acid, based on the total amount of Polyester and aminoplast - heated to 50 to 100 ° C for 10 to 60 minutes.

Manufacture of a paint color

To produce a lacquer color, a clear lacquer in the binder to pigment ratio of 2: 1 with T1O2 pigmented.

Production and testing of the coatings For testing, the clear lacquer or the lacquer color is applied Test panels and glass plates applied and baked. To lower the stoving temperature Lacquer solutions made using low acid number polyesters, 0.5% p-toluenesulfonic acid (based on the total binder) added. The layer thickness of the films on which the The test is carried out, amounts to 40 to 60 μ in all examples. The hardness test is carried out in accordance with DIN 53157, the Test of elasticity according to the methods described above.

Examples 1 to 8 are listed in Table 1, including the type of used Melamine resin is specified. (In the column »Type of Melamine resin «means K that a butylated melamine-formaldehyde condensate was used, while HMM uses a hexamethylol melamine residue Table 2 contains the test values of the coatings, which are derived from the in the following Comparative Examples 1 to 4 described polyesters were prepared.

10

20th

Comparative example 1

1580 g of the symmetrical bis (hydiOxyäthyl) -äthcrs Bis-phcnol-Λ (5 mol) are ^{heated with 400 g of succinic anhydride (4 mol) while passing a stream of nitrogen at 18T 1} C for 6 hours. Remaining amounts of water of reaction are then applied by applying

Table 1

a vacuum of about 20 torr away. The polyester produced in this way has an acid number of 5 mg KOH / g; it is in a xylene-methylethylketone-cyclohexanone mixture (1: 1: 1) dissolved to a 50 percent solution.

Comparative example 2

(Example 2 from US patent 24 60 186) 148 g of phthalic anhydride, 146 g of adipic acid, 278 g of 2-ethylhexanediol (1,3) and 110 ml of xylene are heated to 180 ° C. within 4 hours and to a further 4 hours 200 ^° C., the water formed being separated off via a water separator. 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

(Examples 1 from Ullmann's Encyclopedia of Industrial Chemistry, 3rd Edition, Volume 14, Page 87, Urban & Schwarzenberg, Munich - Berlin, 1963)

1400 g of adipic acid (9.6 mol) and 675 g of ethylene glycol

(10.9 mol) are passed over a nitrogen stream

mes slowly ^{heated to 130 0} C to 140 ° C. Achieved with it

becomes that when the water of reaction is distilled off

no glycol passes over, becomes part of the distillate

given as reflux to the column. Over some

The reaction mixture is ^{heated to 200 °} C. for hours,

then cooled to 150 ⁰ C and the condensation under

Vacuum continued until it fell at 200 torr and 200 ^° C

5 to 8 hours is complete. The waxy polyester has a hydroxyl number of 54 mg KOH / g and a

average molecular weight of 2000; he becomes in one

Xylene-methyl ethyl ketone mixture (1: 1) to a 50 percent strength Solution solved.

Comparative example 4

(Example 2 from Ullmanns Encyclopadie der technischen Chemie, 3rd edition, Volume 14, page 87, Urban & Schwarzenberg, Munich - Berlin, 1963) 316 g of adipic acid (2.16 mol), 480 g of phthalic anhydride (3.24 mol) and 374 g of ethylene glycol (6.5 mol) are slowly heated to 160 to 200 ° C. while passing a stream of nitrogen over it until 118 g of distillate have passed over. It should be ensured that the transition temperature at the top of the column does not exceed 100 ⁰ C. Then a further 19 g are distilled off in 6 hours with increasing vacuum. The polymer has an acid number of 3 to 4 mg KOH / g and a hydroxyl number of 56 mg KOH / g; he is in a xylene-Mcthyluthylketon-Cyclohexanon-Gcmisi'h

(1: 1: 1) dissolved to a 50% solution.

example
No.

Polyester

(Mole)

4 DPG ")
JI ¹ SA ")

i) IiPG
H PSA

Middle
Molecular weight

900

2160

Weight Type of catalyst liinbrenn- I Itti'te Deep drawing Sloppy ratio Melaniin beclin- after ability deep Polyester / 11 In the r / os went DIN after Melnniinhar /. 53 157 DIN 5.J 15 (i to TiO? (SCf) (well) (111111) 70: 30: 0 HMM ") 0.5% pTS *) 150'73 (V 147 9.9 4-- ^r ) HO: 20: 0 HMM 0.5% pTS IW / JO ' 139 > 10 > 5 HO: 20: ^r > 0 HMM 0.5% pTS 150 "/ 30 ' 15.3 8.7 2-5 70: 30: 0 HMM 0.5% pTS 150'7JO ' IJJ > 10 > 5 HO: 20: 0 HMM 0.5% pTS 150'7.HV 125 > OK -5 HO: 20:50 HMM 0.5% pTS Γ) 0 "/ 3 (V 162 H.2 4th HO: 20: 0 K ") (), Γ)% pTS I5O'73O ' 154 H.l 2 i

11th

continuation

At- polyester from

5DPG
3.5 PPE
0.5 A DS *)

DPG 5.5 PSA 0.5 ADS

8DPG 6PSA BSA *)

5DPG
AG »)
4.5 PPE
0.5 ADS

DPG
t PG *)
3.5 PPE
0.5 ADS

4DPG
DG *)
4PSA

Mitt- Gcwiehislcres relationship
Mol polyester too
weight mciaminhar /
to TiO:

1320

1800

1980

1420

1210

1240

70: 30: 0
: 20: 0
: 20: 50
: 20: 0

: 30: 0
: 30: 50
70: 30: 0
: 30: 50

: 30: 0
: 30: 50
: 30: 0
: 20: 50

: 30: 0
: 30: 50
: 30: 0

: 30: 0
: 30: 50
: 30: 0

: 30: 0
: 30: 50
: 20: 50

At the

Mclamin

har / .cs

HMM HMM HMM K

HMM HMM K K

HMM HMM K K

HMM HMM K

HMM HMM K

HMM HMM HMM

catalyst

0.5% pTS 0.5% pTS 0.5% pTS 0.5% pTS

0.5% pTS 0.5% pTS 0.5% pTS 1.2% MA *)

0.5% pTS 0.5% pTS 0.5% pTS 0.5% pTS

0.5% pTS 0.5% pTS 0.5% pTS

0.5% pTS 0.5% pTS 0.5% pTS

0.5% pTS 0.5% pTS 0.5% pTS

Stoving condition
worked

12th

Hardness according to DIN 53 157

150 ° / 30 '
150 ° / 30 '
150 ° / 30 '
150 ° / 30 '

150 ° / 30 '
150 ^c / 30 '
150 ° / 30 '
150 ° / 30 '

150 ° / 30 '
150 ° / 30 '
150 ° / 30
150 ° / 30 '

150 ° / 30 '
150 ° / 30 '
150 ° / 30 '

150 ° / 30 '
150 ° / 30 '
150 ° / 30 '

150 ° / 30 '
150 ° / 30 '
150 ° / 30 '

136 129 151 144

131 156 143 162

127 142 136 158

136 158 147

139 161 123

141 158 151

Ticfzich-

ability

after

DIN 53 15b

(see) (mm)

Blowout

(mm)

9.2

8.3 8.9 7.5

9.2> 1 9.1

9.4 8.2

9.1 8.4

7.8 8.3

> 5> 5

4-5 3

> 5 4-5 4-5 3

> 5> 5 5 3-4

> 5> 5 4-5

> 5

4-5

3-4

> 5

2-3

3-4

) Abbreviations:

DPG - dipropylene glycol

PSA - phthalic anhydride.

HMM = hexamethylol melamine derivative

pTS - p-toluenesulfonic acid "" _nH p " _M i
K - melamine formaldehyde condensate

ADS -

MA

BSA
AG
PG
DG

- succinic anhydride

- ethylene glycol

- propanediol- (t 2)

- diethylene glycol

- based on

Table 2

Comparison example No.

Polyester ims Milt- Weight Lcres Ratio of molar polyester to weight of melamine resin to ΠΟ2

(Mole)

IIÄHA *) BSA ")

1880

1.91 AIII) ·) »750 I'SA) ADS ")

10.9 Ad *)
9.fi ADS

2000

: 30: 0 70:30: 0

: 30: 0: 30: 0

: 30: 70:30: 0

Type of

Melamine-

har / .cs

K-) HMM *)

K HMM

HMM catalyst

liinbrennbedin
worked

llilrtc according to DIN 53

(sec)

0.5% pTS 130'7JO '

0.5% pTS 1 30'73 (V 12b

0.5% pTS IJO'730 '

0.5% pTS 130730 '

0.5% p'TS IJO'730 '

0.5% pTS 130'7JO 'J9

Ticfull

capability

after

DIN

53 15h

(mm)

1.1 1.9

2.0

b.l 8.8

Impact depression

(mm)

> 5

> 5

> 5

continuation

equal

example

Polyester; ius

(Mole)

Middle
Molecular weight

Weight reduction polyester too Melamine! ™ r / to TiO:

Type of

Melnmin-

hiir / es Kiiiii lysiitor

14th

Burn-in

conditional

gungun

hardness
after
DIN
157

(sec)

Tiel'zieh-

capability

after

DIN

53 15b

(well)

Hit low

(mm)

6.5 AG
3.24 PSA
2.16 ADS

2050 70:30:50 K

70: 30: 0 HMM

0.50 / o pTS 130 ° / 30 '25 7.9 > 5

0.5% pTS 130 ° / 30 '22 9.1> 5

*) Abbreviations:

HÄBA = bis (hydroxyethyl) ether of bisphenol A BSA = succinic anhydride K = melamine-formaldehyde condensate HMM = hexamethylol melamine derivative ÄHD = 2-ethyl-hexanediol- (l, 3) PSA = phthalic anhydride ADS = adipic acid AG = ethylene glycol

Claims (1)

18 05 Patent claims: 1. Liquid coating agents based on a mixture of binders and organic s Solvents or water and the binder solubilizing additives or optionally on solvent-free base that acts as a binder A. 50 to 10 percent by weight aminoplasts and / ι ο or their low molecular weight defined precursors and B. 50 to 90 percent by weight hydroxyl-containing and carboxyl-containing linear Polyesters from diols on the one hand and aromatic and aliphatic dicarboxylic acids on the other optionally in addition to the usual additives and auxiliaries contain, the binder also by co-condensation of aminoplasts and / or their low molecular weight defined precursors with the polyesters or by co-condensation of the Starting products of the aminoplast production can have been made with the polyesters, characterized in that polyester with average molecular weights between 300 and 2500 are used, which have been prepared by esterification of mixtures I and 11, wherein Mixture I. 1.1 to more than 70 to 100 mole percent from dipropylene glycol and 1.2 to less than 30 to 0 mol percent of one or more other aliphatic or cycloaliphatic diols in which the hydroxyl functions have 2 to 8 carbon atoms are separated and optionally replaced up to 2 carbon atoms by oxygen atoms which in turn can be separated from one another by at least 2 carbon atoms should be, consists, 5. Coating agent according to claim i to 4, characterized in that linear polyesters are used, for the production of which only adipic acid has been used as component 11.2.