NO122154B - - Google Patents

Description

Use of acetoacetic acid esters as additional accelerators

for polyester molding and coating compounds.

As is known, molding and coating compounds of unsaturated polyesters and polymerizable monomers with a content of hydroperoxides, preferably ketone hydroperoxides} as polymerization catalysts and cobalt compounds as accelerators harden at room temperature to molding parts and coatings.

It is previously known next to the cobalt compounds

to use additional accelerators. Such additional accelerators should then not only support the starting gel formation of the mass, but also accelerate its through-hardening. Especially in the paint area, work with additional accelerators has found its way in, both with regard to a modern conveyor belt-like way of working and also because it thereby be-

appeared faster through-curing leads to coatings with good resistance, i.e. with a smooth, structure-free surface.

As additional accelerators, there were i.a. proposed acetoacetic acid ethyl ester and acetylacetone (compare Deutsche Farben-zeitschrift 14, booklet 11, page 442 (1960)). Both compounds have, compared to many other already mentioned additional accelerators, the advantage of being mixable in the form of liquid at room temperature, with form- or the coating compounds are well compatible substances. They can therefore also be used by the end consumer without difficulty and technical complexity.

Acetoacetic acid ethyl esters, however, are only slightly effective. In order to obtain a sufficient additional acceleration, one must use 4-6 percent by weight, referred to the curable mass, such amounts lead, as is well known, to discolored curing products and have an undesirable softening effect. Acetylacetone is admittedly more effective, but even in smaller concentrations it also causes extremely strong discolouration.

Surprisingly, some were now found among the acetoacetic acid esters which do not have the above-mentioned disadvantages. These are compounds that contain one or more times the rest

CHj-CO-CHg-CO-O-R'-

bound to OH, ether oxygen, -CH=CH- or nitrogen, R meaning a hydrocarbon chain with up to 3 carbon atoms.

The invention relates to the use of acetoacetic acid esters as additional accelerators for polyester molding and coating compounds which consist of mixtures of unsaturated polyesters and polymerizable monomeric ethylene compounds and contain hydroperoxide, preferably a ketone hydroperoxide as a polymerization catalyst and a cobalt salt as an accelerator and optionally compounds that prevent greening are added, the use being characterized wherein the acetacetic ester is a mono- or polyester of

a) an aliphatic mono- or polyalcohol with up to 6 aliphatically bonded carbon atoms which is also substituted with at least one free

hydroxyl group, a methoxy-, a dimethylamino- or. an N-morpholino group, or of

b) allyl or benzyl alcohol.

The pulps modified according to the invention excel

not only with high storage stability - also after the addition of the cobalt accelerator as well as with rapid initial gel formation and

through curing, e.g. for coatings with good resistance, they also have the advantage of not influencing the color of the curing products.

The new additional accelerators are therefore used particularly advantageously

for such masses which, by known methods, have been added with compounds that prevent green colouring. Non-green colored masses with short initial gelation times are admittedly already mentioned in DAS

I.139.269 and in German Patent No. 1.151.932. However, the amine and phosphine addition accelerators mentioned there have the disadvantage that

accelerate the initial gel formation, but not the through hardening to the desired extent.

As examples for additional accelerators that can

used according to the invention must be mentioned: monoaceted diesters of propanediol-1,2, monoaceted diesters of butanediol-1,35 monoaceted diesters of trimethylolpropane, monoaceted diesters of pentaerythritol, the diaceted diester of pentaerythritol, further the aceted diester of glycol monomethyl ether, of allyl and benzyl alcohol, of l-hydroxy-2- methoxypropane, of 1-hydroxy-3-methoxy-butane, of 1-hydroxy-2-dimethylaminoethane, of 1-dimethylamino-2-hydroxypropane, of 1-hydroxy-2-N-morpholinoethane. These compounds are available in a simple way, e.g. by reaction between diketenes with the corresponding alcohols.

They are usually sufficiently effective in quantities

approximately 1 percent by weight, referred to the molding and coating mass. Compounds with R equal to CjHjj» Compounds with free hydroxyl groups are somewhat more effective than the ether-containing products, particularly effective are compounds containing the group CH-j-CO-CH2-CO-0-R- bonded to nitrogen. Of these products there are

often sufficient amounts of about 0.2% by weight and lower to achieve a sufficient acceleration effect.

The new additional accelerators can be used individually,

but also in a mixture with each other as well as in combination with additional accelerators of a different type.

Unsaturated polyesters are understood within the scope of the invention

frame as usual, polycondensation products of ct,3-unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, mesaconic acid and citraconic acid, with polyalcohols such as ethylene glycol, diethylene glycol, propane-, butane-, hexanediol, trimethylolpropane and pentaerythritol.

A part of the unsaturated dicarboxylic acids can be replaced with saturated polybasic carboxylic acids, e.g. succinic acid, glutaric acid, adipenic acid, phthalic acid, tetrachlorophthalic acid, hexachloroendomethylenetetrahydrophthalic acid and trimellitic acid. Further modifications are possible by incorporating monohydric alcohols such as butanol and tetrahydrofurphyryl alcohol, as well as monobasic acids, such as benzoic acid, oleic acid, linoleic fatty acid and ricinic fatty acid.

Furthermore, mention should be made of mixtures of unsaturated polyesters with monomeric unsaturated compounds, which, in addition to the remaining α,3-unsaturated dicarboxylic acids which are the constituents of the polyester, also contain α,Y-unsaturated 'ether residues, whether it is likewise as a constituent of polyesters, e.g. according to DAS 1,024,654 or it is as a constituent of further mixture components, approximately according to German Patent No. 1,067,210 and DAS 1,081,222, which, in addition to their mixture polymerization ability, are also air-curing.

Suitable monomeric, unsaturated compounds that can be mixed polymerized with the unsaturated polyesters are, for example, vinyl compounds such as styrene, vinyltoluene, divinylbenzene, further vinyl esters such as vinyl acetate, further unsaturated carboxylic acids and their derivatives, such as acrylic acid, acrylic esters and acrylonitrile, further methacrylic acid and their corresponding derivatives, allyl esters such as allyl acetate, allyl acrylate, diallyl phthalic esters, triallyl phosphate and triallyl cyanurate.

To increase the storage stability, the molding compounds can contain known inhibitors, e.g. p-benzoquinone, 2,5-di-tert.-butylquinone, hydroquinone, tert.-butylpyrrocatechin, 3-methylpyrrocatechin and 4-ethyl-pyrrocatechin, further copper compounds e.g. copper naphthenate.

Cobalt accelerators are used for the method according to the invention. common highly soluble cobalt compounds such as cobalt octoate and carbon holt naf tenate.

As peroxidic initiators, the commonly used hydroperoxides are also recommended, e.g. cumene hydroperoxide, tetrahydronaphthalene hydroperoxide and tert-butyl hydroperoxide, preferably, however, ketone hydroperoxide such as cyclohexanone hydroperoxide and methyl ethyl ketone hydroperoxide.

The parts and percentages given in the following examples are parts by weight and percentage by weight.

Example 1.

a) The manufacture of the polyester.

An unsaturated polyester produced by condensation of 152

parts maleic anhydride, 141 parts phthalic anhydride and 195 parts propanediol-1,2 and which is stabilized by the addition of 0.045 parts hydroquinone and with an acid number of 47 is dissolved 653t-ig in styrene.

b) The preparation of the lacquer mixture.

20 parts are added to 100 parts of this polyester

styrene. The solution is then mixed with 1.5% cobalt naphthenate solution in toluene (Co content 2.2%) and 0.1% paraffin (melting point 52-53°C).

c) Processing of the lacquer mixture.

The lacquer mixture is applied at 500 g/m on a light wood veneer

which had previously been bleached with an alkaline-activated bleaching agent and coated with 100 g per m contact primer. The contact primer consists of 30 parts nitrocellulose (moistened with butanol), 120 parts ethyl acetate, 35 parts butyl acetate and 20 parts cyclohexanone peroxide powder (95$-ig) - In the following table 1, the initial gelation time as well as the resistance of the varnishes modified according to the invention are compared to unmodified ones material. The resistance was tested after 24 hours of drying on the trailer and polished cover at room temperature and 65% humidity. For assessing the resistance, the numbers 1 (very good), 2 (good), 3 (satisfactory), 4 (poor) are used. The concentrations of the additional accelerator listed in the table refer to the resin mass.

Table 1.

Addition Initial gel Resistance ring time in min. ability

.without addition 9 4

1% acetoacetic acid ethyl ester 9 3-4

1% acetoacetic acid ester of 1-hydroxy-

2-Methoxyethane 7 ' 2

0.2$ monoacetoacetic ester of

propanediol-1,2 8 3 0.6% monoacetoacetic acid ester of propanediol 7 2 1.0% " " of propanediol 6 1-2

1.0% acetoacetic acid ester of 1-hydroxy-

2-butoxyethane 8 2-3

0.6% monoacetoacetic acid ester of

butanediol-1,3 7 2

1.0% acetoacetic acid ester of 1-hydroxy-

3- methoxybutane 8 2-3

Example 2.

The lacquer mixture mentioned in example 1 is mixed with

0.0155 phosphoric acid mono-n-butyl ester and 0.014$ phosphoric acid di-n-butyl ester to avoid a green coloration. Otherwise, proceed as described

in example 1.

Claims (1)

Use of acetoacetic acid esters as additional accelerators for polyester molding and coating compounds which consist of mixtures of unsaturated polyesters and polymerizable monomeric ethylene compounds and contain hydroperoxide, preferably a ketone hydroperoxide as a polymerization catalyst and a cobalt salt as an accelerator and optionally compounds that prevent greening are added, characterized in that the acetoacetic acid ester is a mono- or polyester of a) an aliphatic mono- or polyalcohol with up to 6 aliphatically bonded carbon atoms which is additionally substituted with at least one free hydroxyl group, a methoxy-, a dimethylamino- or an N-morpholino group, or of b) allyl or benzyl alcohol.