DE4004091A1 - Addn. prods. of epoxide oligomers and (meth)acrylic acid - by using 5-ring, 2,3 N or 6-ring, 1-2 N hetero-aromatics as catalysts, to give stable, directly-usable prods. - Google Patents

Abstract

Addn prods (I) are obtd by reaction of epoxide oligomers (II) with (meth)acrylic acid (III) with mol ratio C00H:epoxide gps = (0.95:1)-(1.5:1), pref 1:1. The novelty is that heteroaromatic 5-ring cpds with 2-3N atoms or 6-ring cpds with 1-2 N atoms (IV) are used as catalysts; the prod (I) is obtd without further treatment as a colourless, completely soluble epoxy-(meth)acrylate which is stable in the presence of peroxides at room temp. Reaction mixt contains 0.2-2 wt% (IV) pref alkyl, cycloalkyl, aralkyl, aryl or alkoxy substn prods of the 5-ring cpd or benzo-condensed cpd thereof, esp pref N-alkyl-imidazoles, -benzimidazoles or -benztriazoles, or similar derivs of pyridine, pyridazine or pyrimidine, esp pref 4-methyl-, 2,3-diemthyl- or 2,4,6-trimethyl-pyridine; pyridine and its derivs are purified before use by refluxing with K0H and/or an isocyanate (pref PhNC0), followed by fractional distn; the reactants and catalyst are homogeneously mixed at room temp, and the mixt is heated with stirring, pref under non-isothermic conditions, with continuous or stepwise increase in temp up to 130 (pref 110) deg C. USE/ADVANTAGE - (I) are useful esp as metal and optical adhesives, in microelectronics and as low-shrinkage monomers for use in dental materials. The process enables the prodn of (I) in good yield at moderate reaction temps; the prod is stable and can be used without further treatment to remove catalyst residues (contrast prior-art catalysts which react with peroxides, etc).

Description

The invention relates to a method of manufacture of the addition products of epoxy oligomers with acrylic or Methacyrlic acid, which can be used directly without further treatment usable, stable in storage in the presence of peroxides, colorless and are completely soluble. The received Epoxy (meth) acrylates can be used alone or as a mixture with other radically polymerizable monomers and / or with inorganic fillers and / or fillers based organic polymer for the production of moldings, of Printing plates, adhesive, sealing and filling compounds, from Capping and coating materials as well as Desensitizer applied to carbonless copy paper will. Their use as a metal and optical adhesive, in microelectronics and in Dental chemistry as practically shrink-free curing monomers.

According to the prior art, epoxy oligomers, e.g. B. Bisphenol A diglycidyl ether, with acrylic or methacrylic acid in Presence of tertiary aliphatic or aromatic Amines or onium salts of nitrogen, phosphorus or Sulfur esterified as catalysts. In Descriptions of the invention are e.g. B. dimethylbenzylamine (DE 35 28 461), dimethylaniline (US 31 79 623) and Tetramethylammonium chloride (US 42 93 672) mentioned. Furthermore are mercaptans and thioethers as catalysts (DE 16 93 009), triphenylphosphine (DE 24 29 824), triphenylstibine (A. K. Banthis et al .: Polym. Prepr. Am. Chem. Soc. Div. Polym. Chem. 22 (1981) 209), mixtures of Lewis acids  or cation exchange resins with Lewis bases or Anion exchange resins (DE 35 28 461), chromium III salts (US 46 68,745), piperidine and pyridine (R.V. Molotkov et al .: Plast. Massy 1969 (No. 8) 18) as well as imidazole and 2-alkylimidazoles (JP 59 223 715, 62 108 843). The application of the listed catalysts is compatible with a number of Disadvantages connected.

Peroxides, e.g. B. dibenzyl peroxide, are of tertiary Amines, non-aromatic nitrogen heterocycles, Thio compounds, triphenylphosphine and stibine and Onimum salts with halide ions even at room temperature, partially decomposed at high speed (L. Horner u. a .: Liebigs Ann. Chem. 573 (1951) 35; P. Gosh et al. a .: Eur. Polym. J. 16 (1980) 1115). To compositions with peroxides to be able to manufacture from epoxy (meth) acrylates in a storage-stable manner, the latter are used to remove the catalyst post-treated, e.g. B. with cation exchange resin (BE 8 88 598), or worked up with their chloroform solution (DE 27 50 019). Such post-treatments are labor and consuming materials and causing product losses. Aliphatic amines and imidazole, especially its 2- and 4- Alkyl derivatives, catalyze epoxy oligomerization, whereby the addition products with acrylic or methacrylic acid have an undesirably high viscosity or are completely insoluble will. To stabilize the viscosity, the addition of a strong acid e.g. B. p-toluenesulfonic acid, recommended (CH 6 21 808). Because of their aggressive and corrosive effects but is then the use of epoxy (meth) acrylates, for. B. for dental composites and metal adhesives, no more possible. In the reaction of epoxy compounds with pyridine (H. Lohmann: Angew. Chem. 52 (1939) 407) and with Alkylpyridines (P. P. Kushch et al .: Vysokomol. Soed. A 24 (1982) 312); G. Xue et al. a .: Makromol. Chem .; Rapid Commun. 7 (1986) 37) severe discoloration occurs. Colorless  Epoxy (meth) acrylates can therefore be used when using pyridine and its alkyl derivatives as a catalyst are not expected will. After R. V. Molotkow u. a. (Plast. Massy 1969 (No. 8) 18) pyridine has a significantly lower catalytic Effectiveness as dimethylbenzylamine in the addition of Methacrylic acid on epoxy oligomers. From the tertiary Aromatic amines are known to be spontaneous Initiate radical polymerization of acrylic monomers (W. Cao et al .: Gaofenzi Tongxun 1982 (No. 2) 96). Such, Products polymerized in the synthesis are unusable. The danger of spontaneous thermal polymerization at the Epoxy (meth) acrylate production is also large because that the addition reaction is highly exothermic. Therefore leads the reaction is usually at a relatively low temperature from 60 ° C (DE 27 58 019) to 85 ° C (DE 24 29 824) in long Response times from 60 to 70 or 48 hours. But Even at 120 ° C it took 9 hours for the reaction (DE 16 18 729).

The object of the invention is the development of a method for the preparation of the addition products of epoxy oligomers with acrylic or methacrylic acid using a Catalyst that has no negative impact on the Storage stability of the epoxy (meth) acrylate, especially in Presence of peroxide, on its color, viscosity and Has solubility. The resulting epoxy (meth) acrylate is said to Can be used directly in the presence without further post-treatment of peroxides storage-stable, colorless and completely soluble be. However, the catalyst should be sufficiently effective thus achieving high sales with low temperature loads will.

According to the invention the object is achieved in that Addition reaction catalysts and epoxy oligomer and Acrylic or methacrylic acid hetero-aromatic five-membered ring  compounds with 2 to 3 N atoms or heteroaromatic Six-ring compounds with 1 to 2 N atoms can be used. The alkyl, cycloalkyl, aralkyl, aryl or alkoxy substituents tion products of heteroaromatic five-membered compounds or their benzo-condensed compounds, especially N- Alkyl derivatives of imidazole, benzimidazole and benzotriazole, are suitable as catalysts. The are still suitable Alkyl, cycloalkyl, aralkyl, aryl or alkoxy Substitution products of pyridine, pyridazine or pyrimidine or their benzofused compounds.

Surprisingly, it has now been found that alkyl derivatives des Pridins, e.g. B. 4-methyl, 2,3-dimethyl and 2,4,6- Trimethylpyridine, a much higher catalytic Have effectiveness as tertiary aliphatic amines.

Surprisingly, it was also found that the the reaction of epoxy compounds with pyridine and its Derivatives discoloration in the Addition reaction of epoxy oligomers with acrylic or Methacrylic acid can be avoided if that as Pyridine or its derivatives used by catalyst a special pretreatment can be cleaned. The cleaning takes place according to the invention by heating the pyridine over KOH, preferably over 20 parts by mass in% KOH during 3 Hours, at reflux, subsequent distillation and Heating the distillate with an isocyanate, preferably 2 Fair proportions in% phenyl isocyanate during 3 hours, on Reflux and final fractional distillation. The prepared with pyridine thus purified as a catalyst Epoxy (meth) acrylate is independent of whether the reaction is carried out in air or intergas, colorless.

It was also found that those with N-alkylimidazole or Pyridine and its alkyl derivatives as catalysts  Epoxy (meth) acrylates produced particularly low viscosity and are therefore easy to process.

The epoxy oligomer can be any polyglycidyl ether polyvalent organic compound, especially one polyhydric phenol. It is preferably the Diglycidyl ether of 2,2-bis (4-hydroxyphenyl) propane.

The addition reaction is after mixing the Epoxy oligomers with acrylic or methacrylic acid in the Molar ratio of carboxyl to epoxy groups of 0.95: 1 to 1.5: 1, preferably 1: 1, and the catalyst, preferably 0.2 to 2 mole fractions in%, at Room temperature for 30 to 300 days or with heating up to 130 ° C, preferably up to 110 ° C, during 1 to 6 Hours with stirring.

The acrylic or methacrylic acid can be low Reaction temperatures, preferably up to about 60 ° C, be used unstabilized. At higher The reaction temperature is up to 0.5 Mass fraction in% of a non-discoloring polymerization inhibitors, preferably hydroquinone monomethyl ether, stabilized.

It has now been found that overheating and therefore discoloration and polymerization of the reaction mixture when carried out the reaction under heating can be avoided and the Nevertheless, reaction in a short time, preferably 2 to 4 Hours, is feasible if instead of the usual Isothermal reaction control under non-isothermal Conditions with continuous or gradual increase the reaction temperature, preferably from 80 to 110 ° C, worked and the reaction at sales U in% 90 U 98 is ended by cooling. The course of the reaction will  by titration of the carboxyl and / or epoxy groups tracked.

The epoxy (meth) acrylates produced according to the invention are optically clear as well as colorless and in conventional Solvents completely soluble. You are without Post-treatment can be used directly in all areas of application. Compositions with epoxy (meth) acrylate so produced e.g. B. in the presence of 2 substance proportions in% of Dibenzoyl peroxide, based on monomers, at 4 weeks Room temperature and 2 years at refrigerator temperature stable in storage.

The invention is intended in more detail in some exemplary embodiments being represented:

• 1. In a sulfonation flask with an internal thermometer, stirrer and Reflux coolers are 1 mole of bisphenol A diglycidyl ether (DDGE) and 2 mol methacrylic acid (MAA), stabilized with 0.1 parts by mass in% hydroquinone monomethyl ether, under Add 0.025 mol pyridine (purified by 3 hours Heating with 20 parts by mass in% KOH at reflux, subsequent distillation, treatment of the distillate with 2 parts by mass in% phenyl isocyanate during 3 hours Reflux and heat through final fractional distillation) with stirring quickly up to 80 ° C warmed up and the temperature then within 90 minutes continuously increased to 100 ° C. At this Temperature, the reaction is continued, after 300 minutes sales of 95.1% is reached. The reaction product obtained, called bis-GMA, has one Viscosity coefficient at 23 ° C of 0.5 kPa · s.
• 2. 1 mole of DDGE and 2 moles of MAA stabilized with 0.1 Mass fractions in% hydroquinone monomethyl ether, are in  a sulfonation flask with internal thermometer, stirrer and Reflux condenser in the presence of 0.025 mol of 4-methylpyridine (cleaned by heating for 3 hours at 20 Mass fractions in% KOH at reflux, subsequent Distillation, treatment with 2 parts by mass in% Phenyl isocyanate while refluxing for 3 hours and by final fractional distillation) under Stir quickly heated to 80 ° C and then the temperature within 120 minutes continuously to 100 ° C as well increased to 105 ° C after a total of 210 minutes. After a Total reaction time of 240 minutes is a turnover of 94.6% achieved. The Bis-GMA obtained has one Viscosity coefficients of n = 0.6 kPa · s.
• 3. 1 mole of DDGE and 2 moles of MAA stabilized with 0.1 Mass fractions in% hydroquinone monomethyl ether, are in a sulfonation flask with internal thermometer, stirrer and Reflux condenser with the addition of 0.013 mol of 2,3-dimethyl pyridine (purified by heating for 3 hours at 20 Mass fractions in% KOH at reflux, subsequent Distillation, treatment of the distillate with 2 mass share in% phenyl isocyanate during 3 hours Reflux and heat through final fractional distillation) with stirring quickly up to 80 ° C warmed up, the temperature within 120 minutes 100 ° C and then to 110 ° C within 75 minutes elevated. After a total reaction time of 240 minutes sales of 92.7% were achieved.
• 4. 1 mole of DDGE and 2 moles of MAA stabilized with 0.1 Mass fractions in% hydroquinone monomethyl ether, are in a sulfonation flask with internal thermometer, stirrer and Reflux condenser in the presence of 0.018 mole 2,4,6- Trimethylpyridine (purified by heating for 3 hours with 20 parts by mass in% KOH at reflux, subsequent  Distillation, treatment of the distillate with 2 mass share in% phenyl isocyanate during 3 hours Reflux and heat through final fractional distillation) with stirring quickly to 90 ° C heated and the temperature after 120 minutes to 100 ° C. elevated. At this temperature is on after 240 minutes Sales reached 92.6%.
• 5. 1 mol of DDGE and 2 mol of MAA are mixed with 0.024 mol of 2,3- Dimethylpyridine (purified by heating for 3 hours with 20 parts by mass in% KOH at reflux, subsequent Distillation, treatment of the distillate with 2 Mass fractions in% phenyl isocyanate during 3 hours Reflux and heat through final fractional distillation) to a homogeneous solution mixed and left standing. After 240 days of reaction time at room temperature is a conversion of 98.0% reached. The bis-GMA obtained has a viscosity coefficients n = 0.25 kPa · s at 23 ° C.
• 6. 1 mol of DDGE and 2 mol of MAA are mixed with 0.06 mol of 2,3- Dimethylpyridine (purified by heating for 3 hours with 20 parts by mass in% KOH at reflux, subsequent Distillation, treatment of the distillate with 2 Mass fractions in% phenyl isocyanate during 3 hours Reflux and heat by final fractionation distillation) to a homogeneous solution and ditched. After 61 days reaction time at room temperature reached a turnover of 96.5%. The Bis-GMA obtained has a viscosity coefficient n = 0.62 kPa · s at 23 ° C.
• 7. 10.0 g DDGE and 5.2 g MAA stabilized with 0.1 Mass fractions in% hydroquinone monomethyl ether after adding 0.087 g of benzotriazole with stirring on  Reflux heated to 100 ° C for 340 minutes, after which a Sales of 91.1% has been reached. The Bis-GMA obtained has a viscosity coefficient n = 1.7 kPa · s at 23 ° C.
• 8. 10.5 g DDGE and 5.2 g MAA stabilized with 0.1 Mass fractions in% hydroquinone monomethyl ether after adding 0.084 g of benzimidazole with stirring on Reflux heated to 110 ° C for 180 minutes, after which a Sales of 94.9% is reached. The Bis-GMA obtained has a viscosity coefficient n = 1.5 kPa · s at 23 ° C.

Claims (7)

1. A process for the preparation of the addition products of epoxy oligomers with acrylic or methacrylic acid by reacting the starting components in a molar ratio of carboxyl to epoxide groups of 0.95: 1 to 1.5: 1, preferably 1: 1, in the presence of a catalyst, labeled in is characterized in that heteroaromatic five-ring compounds with 2 to 3 N atoms or heteroaromatic six-ring compounds with 1 to 2 N atoms are used as catalysts, the reaction product without further aftertreatment, in the presence of peroxides at room temperature, stable, colorless and completely soluble epoxy (meth ) acrylate is obtained. 2. The method according to claim 1, characterized in that the catalyst preferably in 0.2 to 2 amounts of substance in% based on the reaction mixture, is used. 3. The method according to claim 1, characterized in that the catalysts the alkyl, cycloalkyl, aralkyl, Aryl or alkoxy substitution products of hetero aromatic five-ring compounds or their benzo-condensates based compounds, preferably N-alkyl derivatives of Imidazole, benzimidazole or benzotriazole. 4. The method according to claim 1, characterized in that the catalysts the alkyl, cycloalkyl, aralkyl, aryl or alkoxy substitution products of pyridine, pyridazine or pyrimidine or their benzofused compounds, preferably 4-methyl-, 2,3-dimenthyl- or 2,4,6- Trimethylpyridine.   5. The method according to claim 1, characterized in that Pyridine and its derivatives by treatment with KOH and / or an isocyanate, preferably phenyl isocyanate, under reflux and fractional distillation before Application as a catalyst to be cleaned. 6. The method according to claim 1, characterized in that the reaction after homogeneous mixing of the starting substances and catalyst carried out at room temperature becomes. 7. The method according to claim 1, characterized in that the reaction by heating with stirring, preferably under non-isothermal conditions with continuous or gradually increasing the reaction temperature to to 130 ° C, preferably up to 110 ° C, is carried out.