DE1163475B - Non-greening coatings and coating agents based on unsaturated polyester resins and monomeric vinyl compounds - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: C09d

Nu he mm:
File number:
Registration date:
Display day:

German class: 22h-3

R 32533 IV c / 22 h
April 21, 1962
February 20, 1964

The production of coatings based on unsaturated polyester resins has in the past Years of increasing importance, especially for the coating of wood in the Furniture, radio and television industries. This appreciation is due to the special Attributed to properties of polyester resins. You can apply coatings in one go Apply about 200 μ and get a high-gloss finish either directly or after sanding and buffing Finishes with excellent filling power, which change the color and grain of the wood let it have a particularly strong effect. The use of unsaturated polyester resins for The production of coatings initially opposed the inhibiting effect of atmospheric oxygen. More or less strongly sticky surfaces were obtained. However, procedures have been developed who overcame these difficulties. Today two methods are widely used technically.

While the one method the inhibiting influence of atmospheric oxygen by adding skin-forming Substances such as paraffin, wax, and the like, turns off to the polyester resin, the other is based Process that one in the polyester resin strongly oxidative drying compounds, such as partial allyl ethers of polyalcohols, condensed.

The hardening of the polyester resins for coatings takes place usually with peroxide polymerization initiators in combination with activators. Included The most common peroxides are methyl ethyl ketone hydroperoxide and cumene hydroperoxide. As activators one uses cobalt octoate or naphthenate.

In the case of hard and glossy drying, ie also oxidatively hardening polyester resins, the cobalt fulfills a double function. In addition to being an activator, it also acts as a drying agent that promotes oxidative drying. Compared to the polyester casting, molding and laminating resins, the additions of cobalt soaps when using polyester resins for the production of coatings are very much higher, on average about ten times as high. This is due to the fact that practically no heat of polymerization occurs in the coatings. The slight heat that occurs as a result of thin layers is quickly dissipated into the subsurface. Relatively large amounts of cobalt are necessary in order to dry the coatings in technically acceptable periods of time. The usage . ^{However, r} > o these relatively large cobalt additions have a significant disadvantage. Both varnishes and non-greening coatings provide resin
Coating agents based on unsaturated polyester resins and monomeric ones
Vinyl compounds

Applicant:

Reichhold Chemie Aktiengesellschaft,

Hamburg-Wandsbek, Iversstr. 57

Named as inventor:
Dipl.-Chem. Hermann Delius,
Hamburg-Lockstedt

types, both the "paraffin type" and the "air-drying type", show after the hardening of the Coatings a more or less strong green color. This phenomenon is particularly evident in the Coating of light, often additionally bleached furniture woods such as birch or maple uncomfortably noticeable. The green color is particularly difficult because its intensity of Case by case as a result of even slight differences between the individual polyester batches that cannot be influenced fluctuates greatly.

If it is interpreted according to French patent specification 1 141 111 and according to the identical Documents of the Belgian patent 554 197 (see also J. Scheiber, Chemistry and Technology of Artificial Harze, Vol. I [Stuttgart 1961], p. 590, footnote 472 a), unsaturated polyesters thereby lighten up that this halogen or chlorine-containing phenyl ester of the pentavalent during the condensation Phosphorus are added, this measure precludes a green coloration of these unsaturated Polyester resins in the case of the one excited with peroxide initiators and accelerated with cobalt soaps Polymerization or curing not complete.

It is also known from German Patent 1 005 267 that with organic peroxides Polymerization of polyester casting resins to be achieved instead of cobalt soap by adding cobalt enolate compounds to accelerate. The higher activity of the cobalt enolates allows their use only in very small quantities with relatively slowly polymerizing unsaturated polyester casting resins, there are larger amounts of cobalt enolates, such as those used for the shorter curing times in paint applications are required, cause disturbing bubble formation in the approaches.

409 509/420

The invention relates to paints and coating compositions based on non-greening coatings unsaturated polyester resins and monomeric vinyl compounds which can be polymerized onto them Addition of soluble cobalt compounds and peroxides with the characteristic that they have an effect on the The amount of cobalt used contain a matched amount of at least one oxycarboxylic acid. Basically all oxycarboxylic acids are suitable for this purpose, but polybasic ίο are preferred Acids such as tartronic acid, malic acid, tartaric acid and citric acid or mixtures thereof.

These acids are expediently added in the form of their solutions, for example in ethanol, for mixing the unsaturated polyester resin and the monomeric vinyl compound, but can also after the end of the condensation before dissolving in the monomer by adding the pure acids to Resin melt done.

Since the addition of the oxycarboxylic acids increases the gelation time of the polyester resin Consequence, the addition must be adjusted to the amount of cobalt octoate or naphthenate used, otherwise the gelation and hardening time will be prolonged too much and unnecessarily. This coordination can easily be done by a preliminary test. Suitable amounts are 0.7 to 7.0 mg of the oxycarboxylic acid to 1 mg cobalt (calculated as metal), preferably 0.7 to 3.5 mg. The following Examples may serve to illustrate the invention:

example 1

80 parts of an unsaturated polyester resin, consisting of a mixture of 70 parts of polyester (made from 2 moles of maleic anhydride, 1 mole of phthalic anhydride and 3.05 moles of 1,2-propanediol) and 30 parts of styrene, stabilized with 0.016% hydroquinone, a viscosity of 250 DIN seconds at 20 ^° C. and an acid number of 28 are diluted with a further 20 parts of styrene to produce a polyester paint. This mixture is made with

0.5 ml cobalt octoate solution (6% metal content),

0.5 ml paraffin solution (5 ° / _o solution in styrene)

0.3 ml silicone oil (1%),

0.4 ml citric acid solution (10% in alcohol)

and
5.0 g of methyl ethyl ketone hydroperoxide

(40% in dimethyl phthalate)

added and further diluted with acetone until a spray viscosity of 20 DIN seconds is reached. After spraying, sanding and buffing to a high gloss takes place after about 6 hours. Of the Polyester paint has a colorless to slightly pink tint. If, on the other hand, the attempt is made without the addition of the Citric acid repeatedly shows the paintwork, even after one week of storage, another one intense green color.

Example 2

The experiment from Example 1 is repeated with the difference that the citric acid solution through a tartaric acid solution of the same concentration is exchanged.

Here, too, you get a polyester finish, which is only a slightly pink tint and no color at all Has a green discoloration.

Example 3
By condensation of

445 g fumaric acid,

40 g phthalic anhydride,
218 g ethanediol,

34 g propanediol-1,2 and
205 g of pentaerythritol triallyl ether in the presence of 0.3 g of hydroquinone

an air-drying unsaturated polyester resin was produced in a known manner. The mixture of 65 parts of polyester and 35 parts of styrene has a viscosity of 200 DIN seconds at 20 ^° C. and an acid number of 30. Varnish solutions were prepared from this unsaturated polyester resin according to the following recipe:

80 g unsaturated polyester resin,
20 g styrene,

0.3 ml silicone oil (1 ⁰ I ₀ Ig),

0.5 ml cobalt octoate solution with a metal content of 6 ⁰ I ₀ ,

5 g of methyl ethyl ketone hydroperoxide (40%).

Immediately prior to the addition of the peroxide, the resist solutions were each mixed with 10 ° / ₀ by weight solutions of different hydroxycarboxylic acids in ethanol. The added amounts of oxycarboxylic acids as well as the gelation times and the colors of the hardened lacquers are shown in the following list in comparison to the blind test:

Type and amount added
Oxycarboxylic acid
in milligrams

35

40

45 50 citric acid
60 tartaric acid
80 tartronic acid

80 malic acid
Lactic acid

Gel time
in minutes

Appearance of the
hardened varnish

colorless to
pale pink

colorless to
weak brownish strong green color

55

60

Claims (3)

Patent claims: 1. Paints and coating agents based on unsaturated non-greening coatings Polyester resins and monomeric vinyl compounds which can be polymerized onto them with additives of soluble cobalt compounds and peroxides, characterized in that an amount of at least one oxycarboxylic acid tailored to the amount of cobalt used contain. 2. Paints and coating agents according to claim 1, characterized in that these 0.7 to 7.0 mg of the oxycarboxylic acid contain 1 mg of cobalt. 3. Paints and coating agents according to Claim 1 and 2, characterized in that they are used as oxycarboxylic acid Contain tatronic acid, malic acid, tartaric acid or citric acid or mixtures thereof. Considered publications: German Patent No. 1,005,267;
French Patent No. 1,141,111;
Scheiber, "Chemistry and Technology of Artificial Resins", 1961, Vol. 1, p. 590. 409 509/420 2.64 © Bundesdruckerei Berlin