DE1278049B - Tear paint for electrical insulation purposes - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN MjRWl · PATENT OFFICE Int. CL:

C09d

EDITORIAL

HOIb German class: 22h-3 21c-2/14 Number: 1,278,049 File number: P 12 78 049.3-43 (B 72381) Registration date: June 22, 1963 Display day: 19th September 1968

The invention relates to impregnating varnishes for electrical insulation purposes with increased permanent heat resistance based on hydroxyl groups, fatty residues and optionally amide, imide and ether groups containing polyester and triazine-formaldehyde condensation products as crosslinking agents Use of benzene hydrocarbons as solvents.

It is known for the production of impregnating varnishes for electrical insulation purposes with higher saturated or polyesters modified with unsaturated fatty acids or their triglycerides with triazine-formaldehyde resins to combine. Such paints have the particular advantage that they are economical to produce and solvents that are relatively less aggressive than other electrical insulation materials, such as B. gasoline and benzene hydrocarbons can be used and their hardening already can be done at relatively low temperatures such as about 120 ° C. However, they have the disadvantage that ao they even when using heat-resistant polyester, such as. B. polyesters of isophthalic acid or Terephthalic acid, suffer a relatively high level of substance degradation under thermal stress. Also surrendered Polyesters with a larger content of unsaturated fatty acids, such as. B. soy fatty acid or Linseed oil fatty acid, modified, paint films that become brittle at high temperatures in a relatively short time. Lacquers made from polyesters with a low fatty acid content are at the same temperature after baking from about 120 to 150 ° C generally too brittle.

It is also known that mixtures of fatty acid-modified polyesters or of di- or polymerized with Fatty alcohols modified polyesters and blocked polyisocyanates as impregnating varnishes use.

These are particularly noticeable when using masked diisocyanate polymerization products, as they are obtained by polymerization of partially blocked diisocyanates, by low Substance degradation at high temperatures. However, larger quantities are required for their production relatively uneconomical solvents such as solvents that are more aggressive than other insulation materials z. B. Esters, ketones and glycol ether esters are required. Their hardening only takes place at comparatively high temperatures.

The production of oil-modified alkyd resins from dialkyl esters of terephthalic acid and theirs Use as a plasticizer has been known for a long time.

Impregnating varnishes for electrical insulation purposes

Applicant:

Dr. Beck & Co. G. m. B. H.,

2000 Hamburg 28, Eiselensweg

Named as inventor:

Dr. Karl Schmidt,

Dr. Gerhard Neubert, 2000 Hamburg

It has also been proposed to use a mixture of oil-soluble varnishes for thermal class B insulating varnishes Phenol-formaldehyde resins and oil-modified glycerine isophthalates and / or glycerine terephthalates with an oil content between 35 and 60% in solvents such as xylene or toluene use.

It has now surprisingly been found that the disadvantage of embrittlement when used of triazine-formaldehyde condensation products as crosslinking agents and the disadvantage of their use large amounts of aggressive solvents when masked diisocyanate polymerisation products are added can be avoided and at the same time products with increased long-term heat resistance according to thermal class F are obtained, if one in impregnating varnishes for electrical insulation purposes on the basis of hydroxyl groups, saturated or unsaturated fatty residues and optionally terephthalic acid containing amide, imide and ether groups and using isophthalic acid polyesters and triazine-formaldehyde condensation products of benzene hydrocarbons as a real solvent used by those polyesters Esterification of 1 mole of terephthalic acid and / or isophthalic acid or their lower dialkyl esters, 0.16 to 0.30MoI of an optionally unsaturated monocarboxylic acid containing 14 to 24 carbon atoms Fat residues, 0.6 to 1.0MoI diprimary glycols, whose hydroxyl groups on average by 3.1 to 6.0 carbon and optionally oxygen atoms are separated from one another and 0.3 to 0.6 mol 3 or 4hydric alcohols have been produced.

Monocarboxylic acids that are suitable for the purpose of the invention are, for example, from vegetable or animal fats or oils obtained fatty acids such as olive oil, soybean oil, tall oil, linseed oil, Tallow fatty acid and stearic acid as well as preferred

809 617/572

at least partly fatty imidecarboxylic acids, ventnaphtha, partly also diluents, such as

as they are, for example, through the implementation of Tri- z. B. Gasoline hydrocarbons and alcohols, with

mellitic anhydride obtained with fatty amines can be used.

den and as modifiers in the British The impregnating varnishes produced according to the invention U.S. Patent 988,828 can be used. 5 are characterized by high thermal stability, such as The main glycols are polymethylene, especially due to their good film flexibility after thermal glycols such as 1,4-butanediol, 1,5-pentanediol and hexane aging. They meet the requirements of VDE-diol-1.6 in question. To avoid turbidity regulations 0362 for thermal class F. Opposite Signs of longer storage at room temperature - conventional impregnating varnishes with similar thermal temperature are low molecular weight glycols like io stability they have the great advantage that they are Ethylene glycol and 1,3-propanediol or preferably from glycols at temperatures from 120 to 130 ° C with branched carbon chains, such as. B. let harden and for their production almost from neopentyl glycol, or preferably and ether bridges, finally, containing less aggressive and inexpensive solutions Glycols such as B. Diethylene glycol and medium are required. By the invention Triethylene glycol, advantageously partly also used, modification with polymerization products from part. Their proportion should, however, be 50 molar proportions of blocked diisocyanates cent, preferably 30 mol percent, and together stability of the impregnating varnish against thermal degradation 70 mole percent, preferably 50 mole percent, does not increase as well as its film properties, such as e.g. B. exceed. the mechanical, electrical properties as well as 3- and 4-valent alcohols are for example GIy- 20 the resistance to solvents and chemicals cerin, trimethylolethane, trimethylolpropane, penta- significantly improved, erythritol and their mixtures. B e i s o i e 1 1

The preparation of the polyester resins can be carried out according to ^p

known methods. Around 970 parts by weight of dimethyl terephthalate, 230 parts Compatibility with the blocked poly- 25 parts by weight of glycerine and 333 parts by weight of butane

Isocyanates in benzene hydrocarbons to give earth-1,4-diol are in a manner known per se at 160

range, however, it is often advantageous to add the poly to 230 ° C with the calculated amount being separated off

add methylene glycols at the end of the esterification, transesterified methanol and then add

and the glycols by adding 367 parts by weight of stearic acid in portions at 190 to wise to incorporate into the resin. In this way, 30 250 ° C can continue to condense until the acid number of the resin

at the same time, the formation of undesirable side effects is less than 10 and one sample in equal

products such as B. that of tetrahydrofuran dissolved in the parts by weight of xylene has a viscosity

Esterification of isophthalic acid with 1,4-butanediol, DIN 53 211 in a 4 mm beaker at 20 ° C of 150 Se-

almost completely prevented. has reached announce.

Triazine-formaldehyde condensation products, the 35 A solution of 210 parts by weight of this resin are suitable for the present process, are examples i _n 2IO parts by weight of xylene is shared with 60 weight playing with higher alcohols etherified MEI of a 50% solution of a Veramin with butanol - or benzoguanamine-formaldehyde resins. Your ethereal melamine-formaldehyde condensation product is 7 to 25 percent by weight, preferred product in butanol and 25 parts by weight, 12 to 20 percent by weight, based on the 40-60% solution of a known manner by solids content of the polyester. _ Polymerization of polyisocyanate partially blocked with phenol The addition of blocked diisocyanate polymer- toluylene diisocyanate in cationic products can be mixed before or after the addition of ethylene glycol acetate at 60 ° C to form a clear solution of the triazine-formaldehyde condensation product. A varnish is obtained, which films are made with to the polyester. It amounts to 2-45 excellent thermal resistance results, 20 percent by weight, preferably between 5 and over _a well in the absence of the polyisocyanate 15 weight percent, based on the solids content of _{e ne} limited shelf life at room temperature of the polyester j. having.

Blocked polyisocyanates, such as those for example

are obtained by reacting diisocyanates with polyhydric alcohols and phenols, give products with lower thermal resistance to 121 parts by weight of trimethylolpropane, 129 parts and are therefore less suitable for the inventive glycerol and 190 parts by weight of a purpose. Fatty amines with an average molecular weight It is advantageous to dissolve the synthetic resins before they are mixed with about 250 and an iodine number of 45. To dissolve the blocked poly- 80 ° C slowly 153 parts by weight of trimellitic acid isocyanate, however, a real solvent anhydride is added, whereby the temperature should not rise ^{significantly above HO 0 C for blocked polyisocyanates such as esters.} The reac glycol ether ester is required. Its proportion can, however, be kept very low when the mixture is gradually heated to 160 ° C. Is less than 6%, 60 _{Subtitle (j} J ₁₃₀ J ₁ z _uga be of 154 parts by weight Tallölfettim generally less than 3%, based on the acid by condensation to 220 ⁰ C a Fettimidendgültigen 50% impregnating varnish, is required. The carboxylic acid Fatty acid monoester mixture produced. Venniches of the blocked polyisocyanate with which, after further addition of 450 Ge Polyester resin can optionally be accelerated to 40 to 70 ° C by briefly heating parts by weight of 1,4-butanediol and 830 parts by weight. 65 isophthalic acid at 190 to 250 To produce the impregnation value according to the invention, the acid number about 15 and the viscosity of a varnish can also contain benzene hydrocarbons as a 50% resin sample in xylene according to DIN 53 211 in real solvents, such as toluene, xylene and sol 4 mm cups are about 250 seconds at 20 ° C.

A solution of 210 parts by weight of this resin in 210 parts by weight of xylene is mixed with 60 parts by weight of a 50% solution of a solution which has been etherified with butanol Melamine-formaldehyde condensation product in butanol and 46 parts by weight of a 65% solution of a partially blocked with phenol in a known manner by polymerization Polyisocyanate produced from toluylene diisocyanate in methyl glycol acetate at 50 ° C to a clear solution stirred. An impregnating varnish which is stable at room temperature and which is already at Cure 120 ° C to a film with excellent permanent heat resistance.

Eg game 3

A fatty imide carboxylic acid / fatty acid monoester mixture prepared as in Example 2 from 166 parts by weight of glycerol, 67 parts by weight of trimethylolpropane, 75 parts by weight of a fatty amine with a mean Molecular weight of about 250 and an iodine number of 45.63 parts by weight of trimellitic anhydride and 280 parts by weight of soybean oil fatty acid is mixed with 830 parts by weight of isophthalic acid at 200 to 220 ° C, 104 parts by weight of neopentyl glycol and 270 parts by weight of 1,4-butanediol esterified, with the addition of the 1,4-butanediol last in three portions in each case only takes place when there is greater sublimate formation at colder parts of the vessel wall occurs. The esterification is continued at 220 to 250 ° C until the acid number is below 10 and the Viscosity of a 50% resin sample in xylene according to DIN 53 211 in a 4 mm beaker at 20 ° C. about 180 seconds amounts to.

80 parts by weight of this resin, dissolved in 40 parts by weight of xylene, are 15.4 parts by weight a 65% solution of a tolylene diisocyanate partially blocked by the polymerization of phenol The polyisocyanate produced is mixed in methyl glycol acetate at 70 ° C. Then the cold solution 30 parts by weight of solvent naphtha, 16 parts by weight of a 50% solution of one with Butanol etherified melamine-formaldehyde condensation product in butanol and 15 parts by weight White spirit added. A clear, curable above 120 ° C. and storage-stable at room temperature is obtained Impregnating varnish with excellent thermal resistance.

Example 4

A condensation product made at 200 ° C. from 166 parts by weight of glycerol, 67 parts by weight Trimethylolpropane and 336 parts by weight of soybean oil fatty acid is at 200 to 250 ° C with 830 parts by weight Isophthalic acid, 104 parts by weight of neopentyl glycol, 106 parts by weight of diethylene glycol and 180 parts by weight of 1,4-butanediol esterified as in Example 3. One from the obtained synthetic resin with melamine-formaldehyde resin and capped polyisocyanate, such as the impregnating varnish produced in Example 1, is storage-stable at room temperature and produces varnish films with excellent thermal resistance.

Example 5

The polyester resin is made from the same raw materials and using the same process as in Example 4 manufactured again (acid number <C 10).

200 parts by weight of the resin obtained are dissolved in parts by weight of xylene. This solution will with 70 parts by weight of a 50% solution of a melamine-formaldehyde condensation product etherified with butanol mixed in butanol at room temperature to form a clear solution.

An impregnating varnish which is storage-stable at room temperature and the varnish films with excellent marks is obtained thermal resistance results.

Claims (4)

Patent claims: 1. Impregnating varnishes for electrical insulation purposes based on hydroxyl groups, saturated or containing unsaturated fatty residues and optionally amide, imide and ether groups Terephthalic acid and isophthalic acid polyesters and triazine-formaldehyde condensation products with benzene hydrocarbons as solvent, characterized in that they contain polyester resins which are produced by esterification of 1 mole of terephthalic acid and / or isophthalic acid or their lower dialkyl esters, 0.16 to 0.30 mol of an optionally unsaturated one Monocarboxylic acid with 14 to 24 carbon atoms containing fatty residues, 0.6 to 1.0 mol of diprimary Glycols whose hydroxyl groups are on average by 3.1 to 6.0 carbon and optionally oxygen atoms are also separated from one another and 0.3 to 0.6 mol of 3- or 4-valent alcohols have been manufactured. 2. impregnating varnishes according to claim 1, characterized in that they contain polyester resins, for their production as glycols a mixture consisting of at least 30 mol percent of one Polymethylene glycol with 4 to 6 methyl groups and up to 50 mole percent of a glycol with branched Carbon chain and / or up to 50 mole percent of an ether bridge-containing glycol has been used. 3. Impregnating varnishes according to Claims 1 and 2, characterized in that they are polyester resins contain, for their production as monocarboxylic acids at least partially fatty imidecarboxylic acids have been used. 4. Impregnating varnish according to Claims 1 to 3, characterized in that they are used as crosslinking agents 7 to 25 percent by weight of a triazine-formaldehyde condensation product and 2 to 20 percent by weight of a polymerization product made from a partially blocked diisocyanate, each based on the solids content of the polyester. Considered publications:
British Patent No. 629,490;
U.S. Patent Nos. 2,905,650, 3,080,331. 809 617/572 9.68 ® Bundesdruckerei Berlin