CS256267B1 - Method of high-molecular epoxy resins production with low dyeing level - Google Patents

Abstract

The solution relates to the field of synthesis and technology epoxy resins. It is technical the problem of preparing very light epoxy resins. The essence of the solution is, performing a polyaddition in an environment containing not more than 50 mg / l of oxygen, optionally v the presence of Sb3, Ir or Sy. , The solution can be used primarily for production epoxy resins.

Description

The invention relates to a process for the production of higher molecular weight epoxy resins with a low level of coloration by polyaddition of diepoxides with divan in an internal atmosphere.

The manufacture of high molecular weight epoxy resins with a low level of coloration is a difficult problem and can only be successfully operated on an industrial scale using high purity Diana stabilized against oxidative thermolysis with special stabilizers. The preparation of very light epoxy resins by alkaline condensation of epichlorohydrin with diane has been successfully managed by using substances with significant affinity for oxygen (sulfur, dithionites, stannates etc.), but in polyaddition technology these substances are ineffective or cause serious problems (turbidity, retardation of filtration etc. .). Successful preparation of very light epoxy resins by polyaddition of diepoxides with diane becomes a serious problem in cases where an unstabilized diane already technical, crystallized, distilled or otherwise treated is available. There is currently no known process for the successful preparation of epoxy resins with a low level of dyeing by polyaddition of diane diepoxides.

Based on extensive theoretical and experimental work, we have now found that high molecular weight epoxy resins with a low level of dyeing by diepoxing with diane can be successfully produced by the process according to the invention, characterized in that the polyaddition is carried out in an environment containing no more than 50 ppm oxygen. 05 "1 wt. % of oxygen scavenging compounds, in particular compounds of trivalent antimony or phosphorus, sulfur tetravalent, or mixtures thereof. The process according to the invention can produce very light epoxy resins even when using unstabilized diane. The color of the product is usually between 0 and 3 points of Gardner color scale and is only affected by the primary color of the diepoxide used.

The negative role of oxygen etops in the inert atmosphere used has not been fully understood until now and generally 99,99% of the atmosphere inertization in the production plant was considered sufficient. Experimental results show that even at an oxygen content of 80 to 100, it is impossible to obtain light epoxy resins from unstabilized dianes, and at 500 pph ^and more oxygen, even stabilized dian does not produce good results.

The oxygen content of the inert dyeing of the polvadice product (Gardner) stabilized dian unstabilized dian 458 6 to 7 15 Dec 320 5 9 105 4 7 82 3 to 4 5 48 1 2 to 3 12 0 0 to 1

Note: the product is an epoxy resin with an average molecular weight of 1678.

Oxygen scavengers, in particular the Sb.sub.2 compounds, and the Noise have an important role in the removal of traces of oxygen from the liquid phase, particularly in the use of solvents. In particular, antimonitans, phosphonates, phosphites, alkyl- or arylphosphines and their salts, sulfur dioxide, rongalite and the like are preferably used.

Nitrogen is preferably used for the inertization of the reaction mixture, but argon, helium and, in some cases, oxide may also be used

256 267 carbon dioxide, the oxygen content of the inert gas being at most 50%, i.e. 0.005 wt. %.

The polyaddition is usually carried out at temperatures up to 155 ° C (below the melting point of diane), but at a low oxygen content in an inert atmosphere, the polyaddition can also be carried out at temperatures of 170 to 190 ° C. Known polyaddition catalysts are used, preferably quaternary ammonium or phosphonium compounds, lithium salts, tertiary amines, betaines and the like. Most of the substances added to the reaction mixture to remove traces of oxygen from the reaction mixture / directly enhance the effect of the polyaddition catalysts or even replace them in full (trialkyl- or triarylphosphines).

The process according to the invention makes it possible to prepare very light, high molecular weight epoxy resins of conventional assortment, in the range of average molecular weights of 700 to 5,000, using polyaddition technology in solution, melt or block.

Example 1

Into the apparatus _from equipped with anchor stirrer and inert gas inlet was charged with 228 g (1 mol) of distilled unstabilized dian, 3.000 g of epoxy resin with average molecular weight 600 and the color 1 (Gardner) and 500 g of toluene »stirring mentioned nitrogen containing 11 and the mixture is brought to reflux and the temperature of the boiling liquid between 147-150 ° C is regulated by taking toluene. To the boiling mixture was added 0.5 g of a 50% aqueous solution of tetramethylammonium hydroxide and allowed to react for 4 hours. After vacuum distillation of the volatile constituents, a product having the following parameters is obtained: obsacepoxide groups 0.246 mol / 100g softening point (ball-ring) 54.5 ° C coloring (Gardner) 1

Example 2

The apparatus described is charged with 228 g of crystallized unstabilized dianne, 510 g of a 340 MW average molecular weight epoxy resin (Gardner), 250 g of toluene.

256 267

The air in the apparatus was displaced by argon containing 3 oxygen, 6 g of dodecyltrimethylammonium bromide and 0.9 g of triphenylphosphine were added to the reaction mixture. The mixture was heated to 120-125 ° C with stirring and allowed to proceed for 3 hours of polyaddition. After distilling off toluene, a product having the following parameters is obtained:

epoxy group content 0,0928 mol / 100 g · softening point (ball-ring) 108 ° C coloration below 1 (Gardner)

Example 3

228 g of Diana, 345 g of a low molecular weight epoxy resin of 340 MW are introduced into the apparatus described above. In an inert atmosphere containing 22 [mu] m oxygen, the mixture is melted at 120 [deg.] C. and 3.1 g of benzyldiethylamine salt is added. The SOg and the homogeneous mixture are poured into pre-coated steel molds. The filled molds are placed in a thermostat with the same inert atmosphere and the polyaddition is allowed to proceed for 24 hours at 120 ° C. After that, the molds are removed, cooled and the product knocked out. Product parameters are:

epoxy content 0.00297 raol / 100 g softening point (ball-ring) 169 ° C color (Gardner) 1 to 2

Example 4

The apparatus described above is charged with 228 g of distilled, unstabilized dianne, 2.800 g of epoxide resin having an average molecular weight of 563 and a 1 to 2 (Gardner) vapor color from the apparatus is expelled with nitrogen containing 11 oxygen, 0.5 g of triphenylphosphite are added. and the mixture is heated to 170 ° C for 90 minutes, then the product is cooled to 100-105 ° C and poured out. It has the following parameters:

epoxy content 0.261 ψοΙ / 100g softening point (ball-ring) 45.5 ° C color (Gardner) 2.

Example 5

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Following the procedure of Example 1, a polyaddition of 228 g of unstained dianum with 3,000 g of an average molecular weight epoxy resin of 600 (Gardner color 1) in the presence of 500 g of toluene was carried out. The polyaddition was carried out under nitrogen containing 48 oxygen, at 150 ° C under catalysis of trimethylbenzylammonium hydroxide (0.5 g). As a reducing agent, 0.5 g of the following compounds are used:

Reducing compound product color (Gardner) sodium antimonite 1 to 2 sodium hypophosphite 1 to 2 rongalit 1 sodium benzenesulfinate 1 to 2 rongalite 0.25 g + hypophosphite sodium 0.25 g under 1

The resulting product is clear, without veil.

Claims (1)

SUBJECT OF THE INVENTION A process for the preparation of higher molecular weight epoxy resins and a low level of coloring by polysaddition of dianto diepoxides in a molar ratio of 1 to 5: 1, under catalysis of bases, in an inert atmosphere at a temperature of more than 100 [deg.]. The polyaddition of diane, in particular unstabilized, with low molecular weight epoxy resins is carried out in an environment containing at most 50 ngs of oxygen, optionally in the presence of 0.05 to 1 wt. % of compounds capable of scavenging oxygen, in particular compounds of trivalent antimony, trivalent phosphorus, tetravalent sulfur or mixtures thereof.