DE1520892C3 - Process for the production of epoxy polyadducts - Google Patents

Description

in which η is a number with an average value between 0 and 0.1, R is the hydrocarbon radical of the dihydric phenol and R 'and R "are glycidyl radicals, of which a small amount, up to 10%, for example, is due to dihydroxypropyl and chlorohydroxyproryl radicals can be replaced.

In the process according to the invention, the amount of trialkanolamine borate is 0.01 to 0.05 parts by weight per 100 parts by weight of polyglycidyl ether of a polyhydric phenol. Examples of trialkanolamine borates are triethanolamine borate, which is preferably used, and triisopropanolamine borate. Such trialkanolamine borates are esters of trialkanolamine and boric acid. They can be prepared in a known manner by heating a mixture of equimolar amounts of trialkanolamine and boric acid to a temperature of approximately 150 ° C. with separation of the water formed, for example by distillation under reduced pressure. _; ,

The trialkanolamine borate can be mixed with the polyglycidyl ether in the abovementioned amount all at once or gradually. The desired amount of trialkanolamine borate is dissolved, for example, in part of the polyepoxide and the concentrated solution obtained is then mixed with the remaining polyepoxide after 24 hours of heating at 120 ⁰ C is apparent If during curing of a polyepoxide with polycarboxylic acid anhydrides as accelerators Trialkanolaminborate in the above amount used, the accelerator and the polyepoxide can be "already mixed together before. This mixture can be stored, so that in each case the required It is also possible to heat a relatively large amount of the mixture to the desired temperature, only then to remove a certain amount by weight of this mixture and to mix with the polycarboxylic anhydrides.

Table I.

Attempt accelerator

Mr

The starting mixtures for the process according to the invention can be cured at elevated temperature with many polycarboxylic acid anhyarides. Some examples of frequently used polycarboxylic acid anhydrides are phthalic acid, hexahydrophthalic acid, tetrahydrophthalic acid anhydrides, pyromellitic acid, endomethylenetetrahydrophthalic acid, methyl-endomethylenetetrahydrophthalic acid, succinic acid, alkyl succinic acid anhydrides, and succinic acid anhydrides, such as tetrahydro-succinic acid anhydrides, such as tetrahydro-succinic anhydrides, such as hexahydro-succinic anhydrides, such as tetrahydro-hydrochloric anhydride, such as hexahydro-succinic anhydrides, hexahydrophthalic anhydrides, tetrahydrophthalic anhydrides, tetrahydrophthalic acid anhydrides, such as tetrahydrophthalic anhydrides. Mixtures of polycarboxylic acid anhydrides can also be used. The inventive method is in particular in the case of using polycarboxylic acid anhydrides as curing agents having a high melting point, for example, "5 more than 100 ⁰ C of practical importance, such as in use of phthalic, tetrahydrophthalic, Pyromellitsäuredi-, endomethylene tetrahydrophthalic and hexachloro- endomethylene tetrahydrophthalic anhydride.

In order to obtain a well cured product, the mutual ratio of polycarboxylic acid anhydride and polyepoxide, i. that is, the equivalent ratio of acid to epoxy groups, a significant factor. This ratio should be more than 0.8 and is usually between 1.0 and 2.3. If phthalic anhydride is used, this ratio, preferably -HCl _{1, is} between 1.1 and 1.7.

It is a great advantage that when the starting mixtures for the process according to the invention are cured with high-melting polycarboxylic acid anhydrides, the processing time at the high temperature usually present can vary widely and can be precisely adjusted to a desired value, which is done with the aid of a suitable amount of trialkanolamine borate Processing time decreases with increasing amount of trialkanolamine borate. If phthalic anhydride is used - and hardening accordingly takes place slowly, then at 120 ^° C. a processing time of between 40-90 and 200 minutes is usually necessary. The processing time is the time after which a re currently located Knitting at a temperature of 120 ⁰ C mixture of 100 parts by weight of polyepoxide to 65 parts of phthalic anhydride has reached a viscosity of 1500 cps, when the viscosity is measured at 120 ° C. If a polyglycidyl ether of 2,2-bis- (4-hydroxyphenyl) -propane with more than 0.5 epoxy groups per 100 g and with a viscosity of 80 to 100 poises at 25 ° C together with triethanolamine borate as an accelerator in an amount of 0 .01 to 0.05 parts by weight per 100 parts by weight of polyglycidyl ether is used, then the processing time is approximately inversely proportional to the square root of the amount of triethanolamine borate.

Fillers, pigments, Colorants and plasticizers, such as aromatic extracts from high-boiling petroleum fractions, such as For example, lubricating oil fractions, asphalt, etc. can be added.

The inventive method is very suitable for the production of hardened castings, for Embedding electrical appliances, for insulating electrical accessories and parts, for manufacturing Laminates with or without the use of solvents and the like mixed with the polycarboxylic anhydride and then molded at elevated temperature

The invention is explained in more detail by means of a few examples. The parts mentioned therein are parts by weight. The polyepoxide used. (Polyepoxide Al) was a polyglycidyl ether of 2 £ -bis- (4-hydroxyphenyl) propane, by reacting the latter with a ten-fold excess of epichlorohydrin in a sodium hydroxide solution had been received. The polyglycidyl ether had a viscosity of 90 poises at 25 ° C, an epoxy equivalent per 100 g of 0.532 and a hydroxy equivalent per 100 g of 0.041.

example 1

In this example, a comparison is made of the curing rate of mixtures of 65 parts of phthalic anhydride and 100 parts of polyepoxide Al, to which an accelerator has been added in an amount in accordance with the following table. The time in hours after which the preparation in question formed a gel ^{at 120 ° C. was taken as decisive for the onset of hardening.} Without accelerators no gelation was observed even after 7 hours at 120 ⁰ C.

XCN = C = O + YCl
HO— HO— —HO

No. amount of
.,. · Accelerator in parts
to 100 parts
Polyepoxide
A 1

Triethanolamine borate 0.05

Ethylene glycol 2

Trimethylol propane 2

Piperidine 0.006

BF3-benzylamine 0.05
Triisopropanolamine

borate 0.05

Yellowil 2 training time 6th Point 7th 1 to 7th 5 to 7th 6 to 6 to 6 to

1 to 2

The very good accelerating effect of the trialkanolamine borates comes from the gel formation time according to Table I (Trials 1 and 6).

Example 2

This example shows that the processing time of mixtures of polyepoxide and polycarboxylic anhydride by suitable choice of Amount of trialkanolamine borate can be adjusted exactly.

There were kept mixtures of 65 parts of phthalic anhydride and 100 parts of polyepoxide Al, which Triäthanolaminborat had been added in an amount in accordance with Table II at 120 ⁰ C. The processing time is from the time out in minutes after which the viscosity of residing on a temperature of 120 ⁰ C preparation had reached a value of 1500 cp when the same was measured at 120 ° C.

Tables The mixtures Triethanolamine Processability at 120 ° C Attempt no. borate parts for 100 time in minutes Share polyepoxide :> 400 Al 258 -. 170 1 ^:. 0.01 134 2 0.02 113 3 0.03 97 4th 0.04 to 6 were too 5 0.05 ^; · ^■: 6th from experiment 1

Immediately after production in the usual way 15 processing time 200 minutes.

fully hardened (2 hours at 130 ^° C. and then 10 hours at 150 ^° C.). The cured moldings had a softening temperature of 149 ° C.

Example 3

100 parts of polyepoxide Al were mixed with 0.015 parts of triethanolamine borate. The viscosity was 90 poises at 25 ° C. After 24 hours of heating at 12O ⁰ C, the viscosity was measured again at 25 ° C and was only up to 96 poises increased. After adding 65 parts of phthalic anhydride, the processing determined in the same way as in Example 2 was

Claims (1)

Claim: Process for hot-stamping mixtures of polyglycidyl ethers with polyhydric phenols on average more than one epoxy group in the molecule and polycarboxylic acid anhydrides with increased Temperature in the presence of the polyepoxy-polycarboxylic anhydride curing promoting hardening accelerators, characterized in that that the accelerator is a trialkanolamine borate in an amount of 0.01 to 0.05 parts by weight used per 100 parts by weight of polyglycidyl ether. Use 15 to 20 percent by weight of other glycidyl compounds, such as polyglycidyl ethers of diphenylolmethane, diphenylolethane, of monoalcohols and phenols and of glycidyl esters of aliphatic monohydroxymonocarboxylic acids in which the carboxyl group is bonded to a tertiary or quaternary carbon atom. Polyglycidyl ethers derived from polyhydric phenols and having less than 0.12 hydroxy equivalents per 100 g can be prepared by reacting a polyhydric phenol with excess epichlorohydrin or dichlorohydrin after adding alkali hydroxide at a temperature of 50 to 150 ^° C., for example. If a dihydric phenol is used as the starting substance, then at least 4 moles and, for example, 10 moles of epichlorohydrin or dichlorohydrin are used per mole of starting substance. The polyglycidyl ether formed is usually a mixture of polyethers of the general formula • For hardening polyepoxides with polycarboxylic acid anhydrides it is known that small amounts of amines are used as accelerators. Also multi-valued Alcohols can be used as accelerators, and the polyhydric alcohols have the advantage of that they can be added to the polyepoxide beforehand without this being detrimental to the The period of use of the mixture obtained is. However, if a polyepoxide is less than 0.12 Hydroxyl equivalent per 100 g of polyepoxide used, then the accelerating effect is the polyvalent one Alcohols only very little. The amine accelerators mentioned, however, generally have the The disadvantage that they cannot be mixed with the polyepoxide before the curing process, because the durability and the resistance of such mixtures at higher temperatures are unsatisfactory From FR-PS 1132 005 is the hardening of Polyepoxides (which can optionally be pretreated with acids) with 1 to 18% trialkanolamine borates known The invention relates to a process for the hardening of mixtures of polyglycidyl ethers polyhydric phenols with an average of more than one epoxy group in the molecule and polycarboxylic acid anhydrides at elevated temperature in the presence of the polyepoxide-polycarboxylic anhydride curing promoting Curing accelerators, which is characterized in that the accelerator used is a trialkanolamine borate used in an amount of 0.01 to 0.05 parts by weight per 100 parts by weight of polyglycidyl ether Examples of polyglycidyl ethers of polyhydric phenols include those of alkylated as well as unalkylated resorcinols, catechins and hydroquinones, of diphenylolalkanes such as bis (4-hydroxyphenyl methane, l, l-bis (4-hydroxyphenyl) ethane and 2 ^ -Bis- (4-hydroxyphenyl) propane. Preferably, polyglycidyl ethers with a low hydroxyl number of, for example, less than 0.12 hydroxy equivalents per 100 g are used have at least 0.47 epoxy equivalent per 100 g, for example liquid polyglycidyl ethers with a viscosity between 100 and 150 poises or one of less than 100 poises at 25 ° C. Mixtures of liquid polyglycidyl ethers of 2 ^ -Bis- (4- hydroxyphenyl) propane and 3 R'-f 0-RO-CH ₂ -CHOH-CH ₂ tOROR "