DE1097677B - Process for the production of epoxy resins - Google Patents

Description

It is known that epoxy resins are obtained by condensation of polyhydric phenols with dihalohydrins. the Products are characterized by a content of epoxy and hydroxyl groups and can through the following formula can be illustrated:

CH ₂ - CH - · H ₂ C - r

CH ₃

CH,

V-OCH-CHOHCH, -

CH,

-OCH ₂ -CH-CH ₂ V

The number of epoxy or hydroxyl groups is equal to the number of condensed halohydrin molecules. The epoxy or hydroxyl groups are later processed with acids or alkaline Means implemented with crosslinking, whereby a hardening occurs and more or less swell-resistant products develop. They are the more resistant to swelling, the fewer 0 Η groups remain, and vice versa. In general the resistance to swelling of the epoxy resins is excellent. However, widespread use of the resins has failed the high price of epichlorohydrin.

It has now been found that epoxy resins with at least the same, but in some cases superior swelling resistance can be produced while saving part of the epichlorohydrin by using mono- or polynuclear benzene-hydrocarbon processes for the production of polyhydric phenols
of epoxy resins

Applicant:

Mining Association GmbH,
Essen, Dortmunder Str. 151

Dr. Joachim Bergmann, Gladbeck (Westphalia),

Dr. Otto Grosskinsky, Dortmund-Kirchhörde,

and Dr. Walter Thürauf, Essen-Kray,

have been named as inventors

substances that have at least two chloromethyl groups in the molecule are etherified and these ethers with halohydrin converts to epoxy-containing resins,

the condensations being carried out in succession in the presence of water or solvents and alkalis. Here, the relatively expensive dihalohydrins or epichlorohydrins are easy accessible chloromethyl compounds replaced. These

Possibility is based on the property of chloromethyl compounds, to react with polyhydric phenols to polyethers, from which then with use high quality condensates containing epoxy groups of dihalohydrin or epichlorohydrin

stand.

The polyethers formed from chloromethyl compounds and polyhydric phenols are linear macromolecules of the following formula:

HO- (T

CH ₃

CH,

0-

-CH ₉

> -CH "

They are formed, for which no protection is sought at this point, by heating the components in aqueous or organic media in the presence of alkaline agents such as NaOH, KOH, NaCO ₃ , K ₂ CO ₃ . Their chain length is influenced by the proportions of the starting materials, the reaction temperature and the type of solvent. For the condensation of polyhydric phenol with chloromethyl group-containing hydrocarbons is suitably used a mole ratio between 1: 1 and 2: 1, a reaction temperature between about 50 and 200 ⁰ C, advantageously over 100 ⁰ C, and is measured the addition of alkali according to the liberated in the reaction evolving hydrochloric acid. The solvents used are mainly polar organic solvents such as alcohols, ketones, ethers, esters and acid amides and their derivatives, e.g. B.

009 699/520

T (JS7 677

Butanol, benzyl alcohol, acetone, cyclohexanone, dioxane and dimethylformamide, in question. When choosing the solvent, its boiling point must be taken into account will. In the case of very low-boiling agents, the application of pressure is sometimes necessary.

Suitable polyhydric phenols are hydroquinone, resorcinol, pp'-dioxydiphenylethane, pp'-dioxydiphenylpropane; suitable chloromethyl derivatives are, in particular, xylylene dichlorides and their methyl derivatives, as well as corresponding ones Compounds of naphthalene.

The reaction of polyhydric phenols with those containing chloromethyl groups Benzene hydrocarbons on the one hand and the halohydrins on the other hand can either be carried out in one step or separately. First, the polyhydric phenols are only substituted with those containing chloromethyl groups Benzene hydrocarbons, the ethers may need before their further processing with halohydrins of a work-up, e.g. B. when further processing with halohydrins should take place in a different solvent. It is therefore advisable not to change the Make solvent and the precondensation and the subsequent implementation of the polyether with Carry out halohydrin in one operation.

If the ether resins are soluble in the organic solvent used, the inorganic salts become separated from the resin solution by filtration; otherwise they are separated from the together with the salts Solvent off and wash off the inorganic salts with water. The separation of the salts can, however also take place following the further processing of the ether with halohydrins on the epoxy resin formed.

The condensation with halohydrin can, as already mentioned, following the condensation of the hydrocarbon containing chloromethyl groups with the polyhydric phenol or already during this condensation be performed. It is also carried out with the addition of alkali in the presence of water or organic Solvents.

As a result of their low content of alcoholic OH groups, the cured resins have a greater solvent resistance than the known epoxy resins. They also have good elasticity And for this reason, too, they are ideally suited as raw materials for paints and casting resins.

example 1

In a stirred vessel, 40 parts of sodium hydroxide are dissolved in 100 parts of water and the solution heated to 90 ⁰ C. 228 parts of pp'-dioxydiphenylpropane are stirred into the hot sodium hydroxide solution, and 88 parts of p-xylylene dichloride are then added to the solution in portions. A resinous product forms very soon and separates out of the solution. After about _{3 to 2} hours, the resin solution is cooled to 60 to 70 ° C. and a further 40 parts of sodium hydroxide are added. The resin is distributed again to form a fine dispersion. 92.5 parts of epichlorohydrin are stirred into the dispersion and, after 3 hours, the separated resin body is separated off.

By washing out with water, the resin is freed from adhering inorganic constituents and im Vacuum dried. 320 parts of a light brown epoxy grape-containing resin are obtained.

Example 2

228 parts of pp'-dioxydiphenylpropane and 88 parts of p-xylylene dichloride are used in 1000 parts of benzyl alcohol dissolved and the solution with 207 parts of potassium carbonate

ίο (anhydrous) added. The reaction mixture is heated approximately 5 hours at 170 to 18O ⁰ C, after which a resin has been formed in the solution. After cooling to 60 to 70 ⁰ C 92.5 parts epichlorohydrin are added to the solution and heating the mixture · an additional 5 hours at 60 to 70 ° C. To remove the inorganic salts, the benzyl alcoholic solution of the resin is first washed with weakly acidic water and then with pure water. The benzyl alcohol is then evaporated off under vacuum. 350 parts of a resin containing epoxy groups are obtained.

Example 3

228 parts of pp'-dioxydiphenylpropane and 88 parts of p-xylylene dichloride are dissolved in 1500 parts of butanol and 140 parts of potassium carbonate are added to the solution. The reaction mixture will be on for about 5 hours Boiling temperature heated. The butanol is then evaporated off and the resinous residue is washed freed from the sodium chloride formed with water. After drying, 250 parts of a light brown color are obtained Resin. Its further processing in an alkaline aqueous solution with 92.5 parts of epichlorohydrin gives 310 parts an elastic epoxy resin.

Example 4

440 Teüe p-xylylene dichloride, 560 parts of bis-chloromethylnaphthalene, 2280 parts of p, p'-dioxydiphenylpropane are dissolved in 1000 parts of dimethylformamide and the solution was heated after the addition of 2070 parts of potassium carbonate with stirring for 8 hours at 170 to 180 ⁰ C. After the reaction has ended, the undissolved inorganic salts are filtered off and the light yellow solution is evaporated in vacuo. 2780 parts of a pale yellow resin are obtained. This is reacted with 925 parts of epichlorohydrin in an aqueous alkaline solution at 70 ° C. to form an epoxy resin. Yield: 2910 parts of epoxy resin.

Claims (2)

Patent claims: 1. A process for the production of epoxy resins based on polyhydric phenols, characterized in that that the polyhydric phenols with mono- or polynuclear benzene hydrocarbons, which have at least two chloromethyl groups in the molecule, as well as condensed with halohydrins, taking the condensations in the presence of water or solvents and alkalis successively performs. 2. The method according to claim 1, characterized in that the solvent used is polar organic Solvent used.