DE1518122A1 - Process for the production of solid epoxy compounds containing aromatic cores - Google Patents

Description

: Reichhold Chemie Aktiengesellschaft, March 29, 1985 2 Hamburg-Wandsbek, Iversstrasse 57 My files: 2022 Pat

Process for the production of solid, aromatic nuclei containing Epoxy compounds

The present invention relates to a substantially improved, industrially applicable process for the preparation of per se known solid epoxy compounds which contain aromatic cores and which are distinguished by the absence of insoluble gel particles. So-called epoxy resins are generally produced by reacting bisphenol A and epichlorohydrin or dichlorohydrin and an equivalent amount of alkali. Depending on the bisphenol / epichlorohydrin molar ratio used, liquid, semi-solid and solid products are obtained and 4000 and softening points by Durran between 52 - 154 ⁰ C - 56 ⁰ C and 140th

The liquid resins and the low molecular weight solid types up to an epoxy equivalent weight of approx. 1000 are produced in one step. The sodium chloride formed during the reaction and excess alkali are removed by washing several times leads .. You can .but also the resin formed in a non-polar Solvents, such as xylene, dissolve from the existing saline solution separate and dehydrate the resin solution by distillation in a circuit. As the water is removed, what remains falls Table salt and can easily be removed from the Hara solution by filtration to be deposited. The epoxy resin can then be distilled off of the solvent can be obtained in vacuo.

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In the case of the higher molecular weight pest resins with epoxy equivalent weights between 1000 and 4000, production in the one-step process causes considerable difficulties. Due to the higher melting points and high viscosities of these Harze.ist a washing process without the use of solvents only under application of pressure, at temperatures between 115 ° and 13O ⁰ C feasible. This process requires a considerable outlay in terms of equipment and has not become established in practice.

The use of solvents is due to the production of the higher molecular weight Solid resins cannot be easily transferred * Higher molecular weight solid resins do not dissolve due to their polar character in non-polar solvents, such as aromatic carbon ^ Hydrogen. They are only in polar solvents, such as higher-boiling ketones, jithers, glycol ethers, esters of glycol ethers and mixtures of such solvents are soluble. Resin solutions with such solvents tend to form in a washing process heavy-duty emulsions. Filtration by distillation dehydrated solutions does not lead to the desired success, because in such solutions due to the polar character of the used Solvent always water and thus common salt remains. In this way, once the solvents have been removed, they will only become cloudy Harse received.,

To get all of these difficulties out of the way . go * a two-stage process is generally used for the production of the higher molecular weight pest resins. In this process, a low molecular weight resin is first produced which, using an al- * "kai is oh acting catalyst, in the second stage.-.- with a calculated

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Keng © bisphenol is converted to the higher molecular weight resin. This two-stage process is internally referred to as a very, very promising process in the future. ^:.: '.__ ;. ■ ■ ■ ,.,. ^ -, _. · ■ -,;. ·

The epoxy resins produced by this two-stage process, which has been judged so favorably, have the following disadvantages: namely always a fluctuating content of insoluble in organic agents and unwanted gel particles which inevitably lead to film defects without subsequent removal.

The present inventive method relates to a one-step process Manufacturing process with improved work-up, as a result of which solid epoxy resins are obtained in a very simple and unexpected manner the usual solid produced in a two-stage process Epoxy resins are superior because the improved one-step process produces resin products which are free from insoluble gel particles in a very economical and reproducible manner.

The present invention relates to a method for producing solid, aromatic cores containing epoxy compounds, the at least contain two terminal epoxy groups, by reacting in the heat of such aromatic nuclei containing compounds, which contain at least two phenoli'scli-. · hydroxyl groups, with Epichlorohydrin and / or glycerol dichlorohydrin in an aqueous-alkaline medium, optionally in the presence of organic solvents, with subsequent work-up of the heterogeneous alkaline reaction mixture in the presence of organic solvents, characterized in that the aqueous phase is preferably separated off which is im

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Reaction vessel contained alkali neutralized by adding appropriate amounts of acidic compounds, then if necessary the remaining aqueous phase is largely separated off, and the remaining water is removed from the resin solution by circular distillation and the hot dissolved resin with. at least as much inert desiccants added as to bind those still contained in the resin solution Traces of water are sufficient, the resin solution is still hot, if necessary with the addition of filtration aids, filtered and if necessary, the solvent is removed by heating in vacuo.

Starting compounds for the present process are polyphenols which have at least 2 phenolic hydroxyl groups in the molecule. Einkernpolyphenole are suitable, such as catechol, resorcinol, hydroquinone and Phoroglucin, and polyphenols having at least two aromatic nuclei, such as bisphenol A (4,4'-dioxydiphenyl-dimethylmethane), 4,4'-Dioxybenzophenon, 4.4 ^f --Dioxydiphenyl, 4,4'-Dioxydiphenylmethane, 4,4'-Dioxydiphenylsulfon, 4,4'-Dioxydiphenyl-methylcyclohexyl-methane and novolaks with 2-5 cores, as they are obtained by acid condensation from phenol and formaldehyde.

Of these polyphenols, 4> 4'-dioxydiphenyl-dimethyl-methane is used preferred.

For reaction with the polyphenols mentioned in aqueous alkaline Solution are epichlorohydrin and glycerol dichlorohydrin. The reaction takes place in a known manner in the heat. For the production of the solid epoxy compounds according to the invention containing aromatic cores in the preferred reaction of bisphenol A with epichlorohydrin or glycerol dichlorohydrin, molar ratios of 0.55 to 0.86 moles of epichlorohydrin or glycerol dichlorohydrin per phenolic hydroxyl group used.

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In the preferred use of 4,4 '~ dioxydiphenyl-dimethylmethane (Bisphenol A), the softening points are by Durran 65-155 ⁰ C and the corresponding Epoxydäquivalentgewichte the obtained epoxy compounds from 400 to 4000.

The inventive method offers particular advantages in the preparation of the higher melting compounds, the softening points from 90 to 155 ⁰ C and 800 Epoxydäquivalentgewichte have to 4000 bar.

In order for the reaction between polyphenol and epichloro or glycerin

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To achieve the most complete conversion possible in dichlorohydrin, ie to obtain products with the lowest possible chlorine content, the aqueous alkali is used in a molar excess over the chlorohydrin. Excesses between 10 to 20 % are preferred. The aqueous alkali can be added to the polyphenol-epichlorohydrin starting mixture from the beginning. In some cases, however, it is advantageous to carry out the addition of the alkali in two parts in order to facilitate the dissipation of the heat generated during the reaction.

The reaction is generally carried out in the absence of solvents. The epoxy compounds formed are only formed after the reaction has ended dissolved in solvents. When producing the compounds with higher softening points, however, it is advantageous to borei / ts carry out the implementation in the presence of solvents, in order to facilitate or accelerate the actual dissolving process after completion of the implementation.

Solvents with a polar character, such as higher boiling probes, are suitable

Ketones, ethers, esters, and solvents that are both ethereal and also have ester groups in the molecule. As a solvent that is already used during the reaction between polyphenol and epichloro or

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Glycerol dichlorohydrin can be used are those with Ester groups unsuitable because of their saponifiability. Ester groups. but containing solvents can be used alone after the reaction has ended. or used in a mixture with other solvents to dissolve the epoxy-containing compound formed. Aromatic hydrocarbons, such as toluene and xylene, are unsuitable as the sole solvent, because in particular the higher melting epoxy compounds are insoluble in them. However, they can be used in a mixture with ketones, esters, ethers and alcohols. Strong polar solvents, such as dioxane and DimethyIfοrmamid, which can be mixed with water in any ratio, are useless as sole solvents for the process according to the invention. The following suitable solvents or solvent mixtures are listed in detail:

Diethyl ketone, methyl n-propyl and isopropyl ketone, methyl isobutyl kotone, di-isobutyl ketone, methyl n-amyl and isoamyl ketone, ethyl amyl ketone, ethyl n-butyl ketone, mesityl oxide, cyclohexanone, di-η and di-isobutyl ethers, n-propyl acetate, n-butyl acetate, sea-butyl acetate, iso-butyl acetate, n-amyl acetate, propyl glycol acetate, butyl glycol acetate, butyl diglycol acetate and mixtures of toluene and / or xylene with one or more representatives of the following solvents: methyl ethyl ketone, diethyl ketone, methyl n-propyl and isopropyl ketone, methyl isobutyl ketone, methyl n-amyl and isoamyl ketone, ethyl n-asyl ketone, ethyl n-butyl ketone, di-isobutyl ketone, isophorone, meaitylo3iird, cyclohexanone, isopropanol, n- and iso-butyl ketone , see-butanol, methyl and "ethyl glycol, butyl glycol, ethyl and butyl diglycol, diacetone alcohol, '": methyl isobutyl carbinol, n-propyl acetate and iso-butyl acetate, sec-butyl acetate, n-amyl acetate, n-propyl glycol acetate, n- Butyl glycol acetate and n-butyl diethylene glycol acetate. . -

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After the reaction has ended, the resin formed is in one of the listed Solvents or mixtures of solvents. Before another Working up, it is necessary to neutralize the excess alkali, because even traces of the alkali remaining in the resin cause undesirable self-hardening of the end product - especially in the Heat - trigger. The neutralization must therefore take place very precisely. The alkali can be neutralized before the aqueous phase is separated off. In the preferred embodiment, the alkaline aqueous' phase from the reaction vessel as largely as possible removed and then weighed. From the difference between the arithmetically determined and balanced amount results in the proportion of the aqueous phase that has remained in the resin solution. The exact one Alkali content is determined by titrating a sample of the separated aqueous phase. ! Will do one of the remaining in the reaction vessel Amount of alkali equivalent amount of an acid or the acidic salt of a polybasic acid added for neutralization. as acidic compounds are hydrochloric, sulfuric, phosphoric, acetic and oxalic acid as well as NaHSO * and NaHgPO, of which, however, phosphorus and oxalic acid and NaHpPOx are preferred. After finished Neutralization, if necessary, the aqueous phase separated from the resin solution is separated off again, and then the resin solution subjected to a so-called circulation distillation. Here a template is used that separates the water and recycling of the solvent into the reaction vessel is permitted. In some cases it is beneficial for better separation of water and solvent and to shorten the cycle distillation between the distillation vessel and receiver oinc packing column to switch.

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After the resin solution has been dehydrated as good as possible by circular distillation, an inert desiccant is added to the solution according to the invention prior to filtration, which is sufficient to bind the traces of water still contained in the resin solution. The following compounds are suitable as inert desiccants, for example: calcined sodium sulphate, calcium sulphate in the form of CaSCL l / ^{2 H} ? ^ 'Anhydrous magnesium perchlorate, anhydrous copper sulphate, water-binding silicic acid preparations, activated aluminum oxide and suitable molecular sieves (zeolites). Of these compounds, anhydrous sodium sulfate and CaSO. 1/2 HpO is preferred as the drying agent for the process according to the invention.

By filtration, optionally after the addition of filtration aids such as asbestos filter paste or silica, carried out the now dry and therefore salt-free resin solution can be used separate from the inorganic constituents.

Resins are obtained by evaporating the solvent under vacuum at temperatures between 100 ⁰ C and 17O ⁰ C, which are clear and transparent and are characterized by absence of insoluble gel particles.

, For many purposes, such as B. the use in painting technology, it is not necessary to evaporate the resin solution. You let can be processed directly, possibly in combination with other paint raw materials, z-u high-quality chemical-resistant paints. ■

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Example 1;

In one equipped with a stirrer, thermometer and reflux condenser 4-1 three neck flasks were made

570 g bisphenol A,

735 g water,

180 g 50% aqueous sodium hydroxide solution,

160 g of methyl isobutyl ketone and

254 grams of epichlorohydrin

carefully heated to 55 ⁰ C and held this temperature for 90 minutes. The mixture was then ^{heated to 85 0} O, and after this temperature had been reached, more was allowed to occur

341'g 10 follow aqueous sodium hydroxide solution

run up. Then the temperature to 95 ⁰ O was increased and held for one, hour. After this time · became heterogeneous!

present alkaline reaction mixture further

450 grams of methyl isobutyl ketone
admitted. By adding

.15 g of 85% H ₃ PO ₄
and others

18 g NaIi ₂ PO ₄

the pH of the aqueous phase was adjusted to a value of 7.2. The reaction mixture was allowed to continue stirring for about 30 minutes after checking the pH value in a separating funnel and separated 1035 g of saline solution. The cloudy resin solution was transferred to a 2-1 three-necked flask and, after adding 50 g xylene

dehydrated by circulating distillation at normal pressure. It was between the template and the flask an approx. 25 cm high with a Raschigringon

filled column switched dead. ^ _1. ,

_BA DOBK51NAL

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After 320 g of aqueous phase had formed in the gate layer, stopped water separation completely. At this time

J was the temperature in the distillation vessel 120 ⁰ C and at the top of the

Column 115 ⁰ C. Now the supply of heat was interrupted, the resin solution was ^{cooled to approx. 95 0} C and

125 g CaSO ₄ · 1/2 H ₂ O

added with stirring. After 15-20 minutes, the resin solution was first separated from the inorganic salts by coarse filtration and then subjected to fine filtration using approx. 1 g of asbestos filter material. The clear resin solution thus obtained was concentrated first under normal pressure and then under a vacuum of 10 Torr up to a Temporatursteigerung of 160 ⁰ C. A plague resin with the following key figures was obtained:

Softening point according to Durran: 112 C epoxy equivalent weight: 1550

Color number of a 4 above solution

in butyl diglycol according to Gardner: '<- 1

The resin was clear, solutions in organic solvents were free from insoluble gel particles. The recovered distillate had a water content determined by gas chromatography of 0.22 ^.

Comparative experiment:

If Example 1 is repeated, but without the use of CaSO, 1/2 H ₉ O, a milky-cloudy end product is obtained. The back distillate had a water content of 3> 8 ^.

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Example 2t

Example 1 was repeated. AnBtolle des CaSO. · 1/2 H ₂ O were however

65 g annealed

used. After similar work-up of the resin solution, a plague became resin with practically the same key figures.

Softening point according to Durrans 112 ⁰ C epoxy equivalent weight: 1544

Parb number of a 40 $ solution

in butyl diglycol according to Gardner: <tC \

This resin, too, was free from haze, and its solutions were noticeable are characterized by the absence of Gclpartehen. A water content of $ 0.14 was determined in the reverse distillate.

Example J:

In a KI three-necked flask equipped with a stirrer , thermometer and reflux condenser

1570 g of water with

460 g of 50% aqueous sodium hydroxide solution mixed and cooled to 25 C, then were successively under stir

. 9 ² 15 g bisphenol A

46 ^ g epichlorohydrin.

ο 100 g methylinobutyl ketone and

25 g of toluene

U ^ filled; After the addition was complete, the temperature was within - ». ~ 5 minutes, increased to 95 ° C and maintain this temperature for one hour ο To remove the air trapped in the highly viscous resin solution and the easier separation of the

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aqueous phase was briefly applied vacuum, by this measure After the stirrer was switched off, the resin solution settled on the bottom of the flask, so that 620 g of the aqueous phase could flow without difficulty to be decanted off, to neutralize what remains in the flask Residual alkaline saline solution became a solution of

50 g NaHgPO ^ in 60 g water
admitted. Simultaneously were

• 375 g of toluene.

400 g of ethyl glycol acetate and

100 g of butanol

added as a solvent for the resin formed. It was heated with stirring to about Sun ⁰ C, the stirrer is stopped and further 1,240 g of neutral salt solution

deducted below. The resin solution was transferred to a 2-1 three-necked flask and drained by circulating distillation. In this example, too, a 25 cm high packed column was connected between the flask and receiver. The recycle distillation up to a temperature increase of 125 ° C inside the flask and of 109 ⁰ C at the top of the column performed. By distillation were

76 g aqueous distillate
obtain.

The resin solution was left at 90 ⁰ C to cool, added 60 g of anhydrous sodium sulfate added and filtered after a period of I5 ■ - 20 mins initially the inorganic salts from the still slightly hazy resin solution was, after addition of 0.5 g asbestos filter material and 0.5 g Kieselguhr finely filtered - '

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A clear resin solution was recovered from the by distilling off the solvent in vacuo up to a temperature increase of 16O ⁰ G a clear, pale yellow and geltellchenfreies solid resin having the following characteristics was obtained:

Softening point according to Dürran: 99 ⁰ C epoxy equivalent weight: 980 Color number of a 40 # solution in butyl diglycol according to Gardner: · <!

Example 4:

Example 3 was carried out using a different solvent mixture repeated.

125 ε methyl slobutyl ketone were added from the beginning and instead the mixture of toluene, ethyl glycol acetate and butanol was used to dissolve of the resin formed a mixture of 275 g of methyl isobutyl ketone, 200 g of toluene and

400 g of butyl acetate

used. After similar working up as in Example 2, a solid resin was obtained with virtually the same characteristics, softening Durran: 98 ⁰ C epoxy equivalent: 940 color number of a 4o $ solution in diglycol Gardner: ■■ <!

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Claims (2)

29. Manul Applicant Reichhold Chemie Aktiengesellschaft, 1518122 2 Hamburg-Wandsbek, Iversstraße 57 My files: 2022 Pat Claims l) Process for the production of solid, aromatic nuclei containing Epoxy compounds which contain at least two terminal epoxy groups, by reacting them in the heat Compounds containing aromatic nuclei and containing at least two phonolic hydroxyl groups with epichlorohydrin and / or G-lycerol dichlorohydrin in an aqueous-alkaline medium, optionally in the presence of organic solvents, with subsequent work-up of the heterogeneous alkaline reaction mixture in the presence of organic solvents, characterized in that the aqueous phase is preferably separated off, the Alkali contained in the reaction vessel is neutralized by adding appropriate amounts of acidic compounds, then if necessary the remaining aqueous phase is largely separated off, and the remaining water is removed from the resin solution by circulating distillation removed and the hot, dissolved resin is mixed with at least as much inert desiccant as necessary to bind the resin in the solution traces of water still contained are sufficient, the resin solution is still hot, if necessary with the addition of piltration aids, filtered and, if necessary, the solvent removed by heating in vacuo. 2) Method according to claim 1, characterized in that as inert desiccant dehydrated sodium sulfate, OaSCh »1/2 HpO, Magnesium perchlorate, dehydrated copper sulphate, water-absorbing silicic acid preparations, activated aluminum oxide or suitable ones Molecular sieves (zeolites) are used. • 909821/1 1 10