Preparation method of low-chlorine refined bleached shellac

Abstract

The invention discloses a preparation method of low-chlorine refined bleached shellac. The preparation method includes: firstly dissolving granular shellac with a sodium carbonate solution to obtain ashellac resin alkali dissolution solution; then carrying out deslagging, temperature adjustment and concentration adjustment sequentially on the shellac resin alkali dissolution solution, and then conducting medium-concentration sodium hypochlorite bleaching to obtain a semi-bleached slurry; then adding assistants into the semi-bleached slurry for adjustment, and then conducting medium-concentration hydrogen peroxide supplementary bleaching by a hydrogen peroxide bleaching solution to obtain a bleached shellac resin solution; carrying out diatomite adsorption filtration on the bleached shellac resin solution, then carrying out acidification precipitation treatment with dilute sulfuric acid or dilute hydrochloric acid with a mass concentration of not higher than 6% to separate out shellacresin; and finally, washing the precipitated shellac resin with water to neutral, then carrying out centrifugal dehydration, crushing and drying, and performing cooling to obtain the low-chlorine refined bleached shellac. The method provided by the invention solves the technical problems of combination of traditional shellac bleaching method with other green bleaching methods, and the prepared low-chlorine refined bleached shellac can meet the preparation requirements of fruit preservatives and even drugs, and is environment-friendly and economical.

Description

technical field

[0001] The invention relates to the technical field of shellac preparation, in particular to a method for producing dewaxed, decolorized and bleached shellac by using granular shellac as a raw material. Background technique

[0002] Shellac, also known as shellac, is an excellent natural resin and the only animal resin. Due to its stable chemical properties, non-toxic, non-irritating, strong plasticity and film-forming properties, good electrical insulation performance, oil resistance, acid resistance, Waterproof, moisture-proof, UV-resistant, widely used in food, medicine, electrical appliances, coatings, machinery, rubber, plastics, leather, paper, printing, ink and military and other industrial sectors. So far, there is no synthetic resin that fully possesses these properties, and shellac is still an important chemical raw material that cannot be completely replaced by chemical synthetic substances. According to statistics, more than 50% of the lac produc...