DD240553B1 - METHOD FOR PRODUCING OPTICALLY TRANSPARENT POLLUTANTS - Google Patents

Description

Field of application of the invention

The invention relates to a method for producing optically transparent Verkappungsmassen based on epoxy resins and Polycarbonsaureanhydriden for the casting of optoelectronic devices such as light-emitting diodes, displays, phototransistors, photodiodes and optoelectronic couplers

Characteristic of the well-known solutions

For encapsulation of optoelectronic components are two-component systems of cycloaliphatic !! (DE-OS 2642465) or liquid aromatic epoxy resins (DE-OS 3016103) known with Polycarbonsaureanhydriden as Harter In the hard component to achieve good processability and certain molding properties such as high transparency stability, as an additive e zinc octoate, low molecular weight acidic polycarboxylic acid esters and optionally organic phosphites incorporated as antioxidants to prevent turbidity by the zinc compound, the zinc can also be used in the form of a mixed carboxylate of 2-ethyl-hexanoure and dicarboxylic acid or preferably dicarboxylic monoester (DD-PS 211120) in DE-OS 3016103 is proposed for the preparation of the casting resins, to admix carboxylic acid anhydride and optionally an organic phosphite to a premix of zinc cocoate and a low molecular weight acidic ester, and to add this mixture to aromatic diglycidyl ethers. These procedures pursue the object of providing the highly viscous zinc octoate However, they have the disadvantage that such quantities of acidic esters, for example of hexahydrophthalic acid and of ethanol or of ethanediol, must be used in such a way that the properties of the reaction resin composition and of the molding materials are adversely affected. The processing time decreases a time of less than 6 hours due to a rapid increase in processing viscosity values above 10 Pa s at 298K. Thermomechanical properties, solvent resistance and water absorption reach values which preclude suitability of the capping compound for up to 373 K and moisture-loadable components Another disadvantage, in particular the procedure according to DD-PS 211120, is the rapid release of the reaction heat during curing above 393 K, so that it comes to local overheating, occurrence of mechanical stresses, microcracks and discoloration The same disadvantage n such reaction resin compositions in which tertiary amines and phosphines and quaternary ammonium and phosphonium salts are used as accelerators, as for example in GB-PS 2090257 This helps with a slow hardening by gradual increase in temperature, but in practice very unoconomic is

Object of the invention

The object of the invention is an economical process for the production and processing of an optically transparent casting resin fui capping of opto-electric devices based on epoxy resins and Polycarbonsaureanhydriden as a harder

Explanation of the essence of the invention

The invention has for its object to develop optically transparent Verkappungsmassen based on epoxy resins and Polycarbonsaureanhydriden as a hardener whose constituents are easily miscible to a homogeneous stable two-component system at temperatures below 323 K, which have good processability and after curing at 393 to 423 This object is achieved by using a resin component consisting of a bisphenol glycidyl ether or by blending at 323 to 363 K from aromatic diglycidic ethers, aliphatic glycidyl ethers, cycloaliphatic !! Polyepoxides and / or polyglycidestern is prepared, and a hard component of one or more polycarboxylic anhydrides, which are used in excess, one or more polyalcohols and a zinc carboxylate-phosphite complex by reacting at 323 to 363K manufactures As the resin component is preferably used Diglycidyl ether of 2,2-bis (4-hydroxyphenyl) propane having an epoxide equivalent weight of 170 to 200 or mixing 10 to 90% by weight of diandiglycidyl ether and 90 to 10% by weight of 3,4-epoxycyclohexylmethyl (3,4-epoxyclocyclohexanecarboxylate)

The hardener component is preferably prepared by reacting from 85 to 95% by weight of polycarboxylic anhydride, preferably hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride or mixtures thereof,

0.5 to 5% by weight of a polyalkylene, preferably ethylene glycol, trimethylolpropane, pentaerythritol, hexanetriol, glycerol, diethylene glycol, propanediol, 3-methylpentane-1,5 or mixtures thereof, 4.5 to 10% by weight of a zinc carboxylate phosphite Complex which is liquid at room temperature, preferably prepared from zinc 2-ethylhexanoate and triphenyl phosphite or diphenyldecyl phosphite under inert gas atmosphere at 323 to 363 K.

The components are mixed before processing at temperatures between 293 and 323 K and hardened at temperatures above 393 K in a few minutes to a maximum of 2 hours in the form to achieve the maximum strength properties, a post-curing of 2 hours at 423 K is sufficient

The zinc carboxylate-phosphite complex is selected from zinc oxide, carboxylic acid, preferably 2-ethylhexanoic acid, and an organic phosphite, preferably triphenyl phosphite or diphenyl decyl phosphite, in molar ratio 1 to 1.5 to 2.5 to 0.5 to 2, preferably 1 to 2 to 1, by dissolving the zinc oxide in the carboxylic acid at 353 to 393 K, stripping the reaction water in vacuo and subsequent reaction of the reaction product with the phosphite obtained The resulting zinc carboxylate Phosphrt complex is a light brown-violet colored liquid with a viscosity When using this compound as an accelerator in the epoxy resin-polycarboxylic acid anhydride system, it has been found that discolorations and mechanical stresses due to local overheating do not occur, so that the components capped with these casting resins have superior temperature retention properties, environmental stability, etc. Obviously has the invention hergest Complex compound in its combination of hardening accelerator, inhibitor and antioxidant particularly good properties for controlling the epoxide-anhydride reaction on

exemplary

example 1

Preparation of the Zinc-Carboxylate-Phosphite Complex (all parts in parts by weight) Zinc oxide (81.3 parts by weight) and 2-ethylhexanoic acid (288 parts by weight) are stirred for 1 hour at 373 K until the zinc oxide has reacted After the reaction water has been completely driven off In vacuo, diphenyldecyl phosphite (374 parts by weight) is added with stirring. The product may optionally be filtered and has the following properties

Viscosity at 298 K (Pas) 0.5

Density at 298 K (g / cm ³ ) 1.068

Zinc content (% by weight) 9.0

Appearance clear, light brown-purple

Example 2

An optical transparent capping compound is made from

resin component

Diandiglycidyl ether with an epoxy equivalent weight of 175 and an iodine color number of 1 hard component

Hexahydrophthalic anhydride 91 parts by weight

Ethylene glycol 1 mass

Zinc carboxylate-phosphite complex according to Example 1 8 parts by mass

The hardener component is prepared by stirring at 343 K under nitrogen for one hour. The reaction resin composition is obtained by mixing 100 parts by weight of the resin component with 100 parts by weight of the hardener component at room temperature. Curing took place in 2 hours at 398 K and 2 hours at 423 K. The characteristics of the reaction resin composition and Reaction resin molding material prepared therefrom are listed in Table 1 for all examples

Example 3

resin component

Diandiglycidyl ether with an epoxide equivalent weight

SAEpoxidcyclohexylmethyMS ^ -epoxy) cyclohexane

carboxylate with an epoxide equivalent weight of 140

hard component

hexahydrophthalic anhydride

Methylhexahydrophtalsaureanhydnd

trimethylolpropane

Zinc carboxylate-phosphite complex according to Example 1

67.0 parts by mass

33.0 parts by mass

44.0 parts by mass 44.0 parts by mass 4.0 parts by mass 8.0 parts by mass

The resin component is prepared by stirring at 343K for one hour, and preparing the hard component by stirring at 353K under nitrogen for 2 hours. The reaction resin composition is obtained by mixing 100 parts by weight of the resin component with 100 parts by weight of the hard component at room temperature. Curing takes place at 398 K in 2 hours and 2 hours at 423K

Example 4

resin component

Diglycidyl ether of bisphenol A having an epoxide equivalent weight of 175: 50.0 parts by weight of diglycidyl ether of bisphenol F having an epoxy equivalent weight of 161: 50.0 parts by weight of hard component

Hexahydrophthalic anhydride 90.0 parts by mass

Ethylene glycol 2.0 parts by mass

Zinc carboxylate-phosphite complex of zinc isodecanoate and triphenyl phosphite, analogously to Example 1 he'gestellt 8.0 parts by mass

The preparation and processing are analogous to Example 3

Example S (Comparative Example from DD-PS 211120)

resin component

3,4-Epoxicyclohexylmethyl- (3,4-epoxi) -cyclohexancarboxy-

lat with an epoxide equivalent weight of 140 20.0 parts by mass

Diandiglycidyl ether with an epoxide equivalent weight

of 175 80.0 parts by mass

hard component

Hexahydrophthalic anhydride 85.9 parts by weight

Diphenyl-alkyl phosphite 5.4

Zinc carboxylate with a zinc content of 19.0Ma% on the

Basis of ethylhexanoic acid and ethylene glycol monohexa

Hydrochloric acid radicals in molar ratio of 1 1 8.7 parts by mass

The reaction resin composition is obtained by mixing 100 parts by weight of the resin component with 102.5 parts by weight of the hardener component at room temperature. Curing took place in 2 hours at 373 K and 8 hours at 393 K. If the curing is started at 398 K analogously to Examples 2 to 4, Even with a reaction resin mass of 4 g, a cracked and locally brown colored molding material is formed

Example 6 (comparative example according to the prior art)

resin component

Diandiglycidyl ether with an epoxide equivalent weight of 175

hard component

Acidic ester of ethylene glycol and hexahydroxy

Phthalic acid in the molar ratio 2 15 parts by mass

Zinc octoate 6 parts by weight

Diphenyldecyl phosphite 7 parts by mass

Hexahydrophthalic anhydride 72 parts by mass

The hardener component is prepared by mixing the ingredients at 333K. The reaction resin composition is obtained by mixing each 100 parts by mass of the components at room temperature. Curing was carried out as in Example 2

Table 1 Characteristics of Reaktionsharxmasse and reaction resin molding materials

Examples 2 3 4 5 6 Reaction resin compound processing time 24 24 24 16 16 (Hours) Processing Viscosity (Pa s) 0.7 0.8 0.6 1.1 1.5 Gel time (min) at 398K 9 20 6 10 8 30 11 50 8 10 at 423K 5 35 2 05 4 20 2 05

Examples 2

Temperature maximum at 20 g mass and 398 K ambient temperature ^) 418 Reaction resin molding material Glass transition temperature (K) 389 Martens heat resistance (K) 378 Water absorption after 4 days at 296K (%) 0.1 Transparency at d = 4 mm and = 560 ran (%) 94 = 450nm (%) 90 Transparency at 560 nm after 3,000 hours Aging at 358 K (%) 93

4 5 -A- 240 553 3 419 453 6 423 390 378 445 389 379 365 373 382 0.1 0.2 355 0.2 92 90 0.5 93 89 70 90 90 71

91

88

88

Claims (2)

1. A process for the preparation of optically transparent Verkappungsmassen consisting of one or more compounds having at least one epoxy group, polycarboxylic and auxiliary substances and additives and their resin and Harter components are mixed before curing at 393 to 423 K at temperatures below 323 K, characterized characterized in that the hardener component is converted by reaction under an inert gas atmosphere at 323 to 363K from 85 to 95% by weight of polycarboxylic acid anhydride, preferably hexahydrophthalic anhydride, Methylhexahydrophthalic anhydride.Methyltetrahydrophthalsäureanhydrid or mixtures thereof, 0.5 to 5% by weight of a polyhydric alcohol, preferably ethylene glycol, trimethylolpropane, pentaerythritol, hexanetriol, glycerol, diethylene glycol, propanediol, 3-methylpentanediol-1,5 or mixtures thereof, From 4.5 to 10% by weight of a zinc carboxylate-phosphite complex at room temperature, preferably from zinc 2-ethylhexanoate and triphenyl phosphite or diphenyldecyl phosphite obtained by dissolving zinc oxide in 2-ethylhexanoic acid, removing the reaction water in vacuo and then reacting with Triphenyl phosphite and / or diphenyldecyl phosphite is produced is prepared. 2. The method according to claim 1, characterized in that the starting materials of the zinc complex zinc oxide, 2-ethylhexanoic acid and phosphite are used in a molar ratio of 1 to 2 to 1.