Cellulose acetate is a thermoplastic resin obtained by esterification of acetic acid as a solvent and acetic anhydride as an acetylating agent under the action of a catalyst.
Cellulose acetate has a variety of preparation methods and a wide range of applications. In this article you will be introduced to the preparation and main uses of cellulose acetate.
Method for producing cellulose acetate
1. After drying the refined short cotton linters, it is activated by acetic acid, and then esterified with acetic acid and acetic anhydride in the presence of an acetic acid catalyst to make it aceticate, and then hydrolyzed with dilute acetic acid. The catalyst is neutralized to precipitate the product deeply, and the cellulose acetate is obtained by deacidification, pre-cooking and drying.
2. After drying the refined short cotton wool, it is activated by acetic acid, and then esterified with 7 times of the mixed mixture of acetic acid and acetic anhydride of refined short cotton lint in the presence of a sulfuric acid catalyst to make it aceticate, and then dilute acetic acid. Hydrolysis to the desired degree of hydrolysis (1.72 to 1.95). The catalyst is neutralized, and the product is precipitated, and after deacidification washing, fine boiling, and drying, a cellulose acetate is obtained. In the acetylation reaction, cellulose diacetate and cellulose triacetate can be obtained by changing the amount of the mixed acetic acid and acetic anhydride. The amount of the mixture of acetic acid and acetic anhydride is 8.5 times that of the refined short cotton lining, and the reaction is hydrolyzed with acetic acid to a degree of substitution of 2.28 to 2.49 to obtain cellulose diacetate. The amount of the mixture of acetic acid and acetic anhydride is 10 times that of the refined short cotton linters, and the reaction is carried out by hydrolysis of the acetic acid to a degree of substitution of 2.8 to 2.9 to obtain cellulose triacetate.
Main use of cellulose acetate
It is used as an enteric coating for the manufacture of pharmaceuticals, a cellulose acetate filter membrane, etc., and is used for making cellulose acetate plastics, cellulose acetate filtration membranes, and the like.
Cellulose acetate can be divided into two vinegar-spun cellulose acetate, two-acetic acid grade cellulose acetate, and cellulose triacetate depending on the product.
1. Diacetate spinning grade cellulose acetate: Spinning grade products are internationally recognized and have not found non-toxic and harmless products of alternative materials. Its most important and main use is as filter equipment, especially Cigarette filter is very large, and it is used as a medical filter device, such as blood filter equipment; it can also be used for spinning, with silk luster, used as a high-grade suit.
2, two vinegar plastic grade cellulose acetate: mainly used for making plates and sheets, the main products are glasses frames, advanced tool handles and so on.
3, cellulose triacetate: mainly used as electronic film, such as liquid crystal display polarizer, film film, camera film.
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