DE1195491B - Additional accelerators in polyester molding compounds - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

C08g

German KL: 39 b -22/10

Number:
File number:
Registration date:
Display day:

1195 491
G36999IVc / 39b
7th February 1963
June 24, 1965

Polyester molding compounds, which are known to contain unsaturated polyesters as the most important constituent, have achieved great importance in technology. The very extensive literature dealing with the Composition, application and technology of polyester molding compounds is concerned among others in the standard works »Polyesters and their Applications« (Bjorksten, Tovey, Harker and Henning, New York, Reinhold Publishing Corporation, 1956) and "PolyesterResins" ίο (Lawrence, N.Y., Reinhold Publishing Corporation, 1960).

It is known that by adding suitable accelerators, those introduced by peroxides as hardeners can be used Curing can be carried out without external heat input at normal room temperatures. the The hardener and accelerator used must, however, be coordinated with one another. Harder are organic hydroperoxides or acyl peroxides. Accelerators are mostly organic metal compounds, such as salts of cobalt or manganese with organic carboxylic acids. Also organic amino compounds, especially those with tertiary amino groups, preferably with an aromatic one Substituents are used as accelerators.

In addition, additional accelerators have become known from the literature (cf. Weigel, Katalytische Lacquer hardening and its raw materials, Curt R. Vincentz, Hanover, 1962), mostly in association be used with cobalt accelerators. Such are z. B. amines, preferably tertiary Character, or their salts with weak acids; also acetylacetone or esters of acetoacetic acid with Methanol, ethanol or other alcohols can be used.

Despite their advantages, the additional accelerators also have considerable disadvantages, which make their use in practice very difficult. First of all, they cause a significant decrease the storage stability of the molding compounds, which are only partially corrected by adding inhibitors can. The additional amine-based accelerators also cause corrosion the metal containers commonly used for shipping polyester resin solutions. Another disadvantage is that the polyester surfaces hardened with the use of an amine when exposed to light yellowing extremely strongly.

In the case of acetylacetone, it is disadvantageous that the favorable concentration range is very narrow. The esters the acetoacetic acid again require for a satisfactory development of its effectiveness as an additional additional Accelerator in polyester molding compounds

Applicant:

Glasurit-Werke M. Winkelmann AG,
Hamburg-Wandsbek, Am Neumarkt 30

Named as inventor:

Dr. Erhardt Knappe, Hiltrup (Westphalia);

Dr. Dezsö Peteri, Münster (Westphalia)

Borrowed accelerators the use of relatively high concentrations of about 4 to 6% (based on the workable approach). In these high concentrations comes the character of these compounds as additional solvents that are not polymerized under normal conditions, with all the typical disadvantages. Due to the high solvency of the esters of the Acetoacetic acid is then often used for the stains applied to wooden materials before painting loosened and the binding agent underlying insulating layers and layers of hardener primers Swollen to reduce quality and adversely affected in terms of their technical lacquer properties. In order to the increase in the sensitivity of the hardening paint system appears to be related to stand against wood moisture. However, the influence exerted by the esters of acetoacetic acid is particularly troublesome in the direction of the creation of discolored layers of paint.

In general, cobalt-containing accelerators are used without the addition of additional Accelerate polymerization products with light pink tones, like them in particular are desirable for light and clear areas. Those made using esters of acetoacetic acid Paint build-ups, on the other hand, tend to undesirably discolour green, especially during storage in the dark, which lead to serious deterioration in the quality of the painted products. This "dark greening" is caused by residues of alkaline-activated bleaching agents, which result in too brief drought or inadequate drying methods are still in the wood, sometimes up to Increased unbearability.

509 597/441

The subject of the invention is the use of monosubstituted or polysubstituted compounds in the amide group Amides of acetoacetic acid, the amide nitrogen also being part of a cycloaliphatic ring can be, as an additional polymerization accelerator in polyester molding or coating compositions that unsaturated polyesters, polymerizable monomeric compounds, organic peroxides and common ones Contains heavy metal accelerators and, if necessary, customary additives.

The compounds to be used according to the invention are according to known ones here unclaimed methods and correspond to the formulas:

CH ₈ -CO-CH ₈ -CO-N;

CH ₈ -CO-CH ₂ -CO-Z

II

20th

R ₁ and R ₂ can mean: aliphatic branched or unbranched hydrocarbon radicals; aliphatic hydrocarbon radicals in which one Η atom of one or more methyl or methylene groups has been replaced by halogen or a hydroxyl, amino, sulfhydryl or alkoxyl group; aromatic hydrocarbon radicals in which one or more Η atoms can be substituted by one or more hydroxyl, alkoxyl, alkyl, halogen groups; aromatic hydrocarbon radicals which contain one or more heteroatoms, such as N, S, O, in the ring and in which one or more Η atoms can be substituted by one or more hydroxyl, alkoxyl, alkyl, halogen groups; cycloaliphatic hydrocarbon radicals in which one or more H atoms can be substituted by one or more hydroxyl, alkoxyl, alkyl or halogen groups; mixed aliphatic-aromatic hydrocarbon radicals in which one or more Η atoms can be substituted by one or more hydroxyl, alkoxyl, alkyl or halogen groups.

Z represents a cycloaliphatic radical with the amide nitrogen atom in the ring; this ring can too instead of carbon atoms contain further heteroatoms in the ring and / or the ring by corresponding Substituents may be substituted.

It is advantageous to use those amides of acetoacetic acid which are soluble in the molding composition.

The singly or multiply substituted amides of acetoacetic acid to be used according to the invention unite in their molecular structure not only the effectiveness of the amine-based accelerators and the accelerators, which apparently act due to their keto-enol tautomerism, like the esters of Acetoacetic acid, but surprisingly they develop a pronounced potentiated effect.

Additions of only 0.1 to 0.5 per cent, calculated on the processable batch, are sufficient to effectively increase the accelerating effect of the cobalt compounds.

As a result of the only small amounts of mono- or polysubstituted amides required Acetoacetic acid, the disadvantages described above are avoided by the addition of the relative large amounts of esters of acetoacetic acid are caused.

Surprisingly, when the substances according to the invention are used, none of the others occurs either hitherto known additional accelerators have inherent disadvantages. Despite the increase in If they react to the known additional accelerators, they impair the storage stability the polyester paints made with them do not. The main advantage of the invention Compounds to be used, however, are that the paint layers turn yellow in the light and turn green can be prevented in the dark, the latter even when in production, in particular from the wood bleaching process, there are influences that otherwise favor these disturbing phenomena maintain.

The molding compositions produced by using amides of acetoacetic acid according to the invention are used for the production of molded parts and, in particular, of paint coatings.

The parts mentioned in the following examples are parts by weight. For carrying out the examples In all cases described below, a paint mixture consisting of 55 parts of an unsaturated one Polyester with an acid number of 45, which is made in the usual way from 2 moles of maleic acid and 1 mole of phthalic acid and 3.2MoI of 1,2-propylene glycol and obtained by Addition of 0.02 part of hydroquinone has been stabilized, 45 parts of styrene, 0.1 part of paraffin, 0.02 part of cobalt used in the form of cobalt naphthenate, which in the examples is referred to as "polyester paint" for short referred to as.

example 1

a) To 100 parts of polyester paint 3 parts of a 50% solution of cyclohexanone peroxide in Triethyl phosphate mixed in and the mixture immediately on with an alkaline-activated bleach Pre-bleached light wood veneer applied in a layer thickness of about 300 My (comparison).

b) To 100 parts of polyester paint are first 0.5 parts of methyl acetoacetate and then 3 parts of a 50% solution of cyclohexanone peroxide in triethyl phosphate and mixed Immediately apply the mixture to a light wood veneer that has been pre-bleached with an alkaline-activated bleach applied in a layer thickness of about 300 My (comparison).

c) To 100 parts of polyester paint are first 5 parts of methyl acetoacetate and then 3 parts of a 50% strength solution of cyclohexanone peroxide in triethyl phosphate are added and the Mix immediately onto a light wood veneer pre-bleached with an alkaline-activated bleach applied in a layer thickness of about 300My (comparison).

d) To 100 parts of polyester paint are first 0.5 parts of acetoacetylbenzylamide and then 3 parts of a 50% solution of cyclohexanone peroxide mixed in triethyl phosphate and the mixture immediately activated with an alkaline Bleach pre-bleached light wood veneer applied in a layer thickness of about 300 My.

e) To 100 parts of polyester lacquer, 0.5 parts of acetoacetylpiperidide are added first and then

10

3 parts of a 50% solution of cyclohexanone peroxide in triethyl phosphate are added and the Mix immediately on a light wood veneer pre-bleached with an alkaline-activated bleach applied in a layer thickness of about 300 My. After a while the coatings have gelled, and although the coating according to

a) in 31 minutes,

b) in 31 minutes,

c) in 24 minutes,

d) in 17 minutes,

e) in 15 minutes.

After lying in the dark for some time, the coatings according to a) and b) are light pink, the coating according to c) is clearly yellow-green, the coatings according to d) and e) are colored light pink.

20th

Example 2

a) The polyester varnish is pre-bleached with an alkaline-activated bleach and then with a commercially available, conventionally made of medium-viscosity nitrocellulose and an indifferent one Synthetic resin, dissolved in common inert solvents and containing 10% cyclohexanone peroxide offset hardening primer coated wood veneer applied in a layer thickness of about 500 My (comparison).

b) To 100 parts of polyester paint, 0.5 part of ethyl acetoacetate is mixed in and then as further processed under 2, a) (comparison).

c) To 100 parts of polyester paint, 5 parts of ethyl acetoacetate are mixed in and then as continued under 2 a (comparison).

d) 0.5 part of acetoacetyl-p-methylphenylamide is added to 100 parts of polyester paint and then continue working as under 2 a).

After a while the coatings have gelled, namely the coating according to

a) in 26 minutes,

b) in 25 minutes,

c) in 18 minutes,

d) in 19 minutes.

The coatings according to a) and b) are light pink, the coating according to c) is clearly yellow-green, the coating according to d) is colored light pink.

Example 3

A polyester molding compound of the composition: 55 parts of an unsaturated polyester with the acid number 45, which is prepared in the usual way from 2 mol maleic acid, 1 mol phthalic acid and 3.2 mol 1,2-propylene glycol obtained and stabilized by adding 0.02 part of hydroquinone, 45 parts of styrene, 0.01 part of cobalt in the form of cobalt naphthenate, 0.4 part of acetoacetylpiperidide, 0.5 part of a 50% strength Solution of cyclohexanone peroxide in triethyl phosphate, is poured into a test tube and at Cured at a constant temperature of 20 ° C. A molded part is created, which after removal of the test tube is clear and free of cracks and cracks.

Claims (1)

Claim: Use of amides of acetoacetic acid which are singly or multiply substituted in the amide group, where the amide nitrogen can also be part of a cycloaliphatic ring, as an additional polymerization accelerator in polyester molding or coating compositions, the unsaturated polyester, unsaturated polymerizable monomeric compounds, organic peroxides and common heavy metal accelerators as well as customary additives, if applicable. When the registration was announced, a specimen was displayed.