What is cellulose diacetate used for?

For most people, cellulose diacetate is a very unfamiliar thing. In fact, cellulose acetate is a thermoplastic resin. This substance has many characteristics, such as high water permeability, very simple processing, and very high selectivity. From the appearance, cellulose acetate is a white or transparent powder. So what are the uses of cellulose diacetate?

Application of Cellulose Diacetate:

Used in the manufacture of enteric coatings for pharmaceuticals, cellulose acetate filter membranes, etc.; used in the manufacture of cellulose acetate plastics, cellulose acetate filter membranes, etc.

Cellulose acetate can be divided into diacetate spinning grade cellulose acetate, diacetate plastic grade cellulose acetate and triacetate cellulose according to different products.

1. Diacetate spinning grade cellulose acetate: Spinning grade products are internationally recognized and non-toxic and harmless products that have not yet been replaced. Its most important and main use is as a filter material, especially cigarette filters, which are used in large quantities. In addition, it is used as a medical filter material, such as blood filter materials. At the same time, it can also be used for spinning, with a silk luster, and is used as the lining of high-end suits.

2. Diacetate plastic grade cellulose acetate: mainly used to make plates and sheets. The main products include eyeglass frames, high-end tool handles, etc.

3. Cellulose triacetate: Mainly used as electronic films, such as polarizers for liquid crystal displays, movie films, and camera films.

Miscible substances

Cellulose acetate (AF) and triacetate (TAF) are often mistaken for the same fiber. Although they are similar, they have different chemical compositions. TAF is described as a general molecular structure and is the most basic acetate ester, which does not contain hydroxyl groups. AF is considered a modified or secondary acetate ester containing hydroxyl groups in the molecular chain. Although TAF is rarely produced today, it has a higher degree of esterification than AF.

preparation

1. After the refined short cotton linters are dried, they are activated with acetic acid, and then esterified with a mixture of acetic acid and acetic anhydride in the presence of acetic acid catalyst to make them acetic, and then hydrolyzed with dilute acetic acid. Neutralize the catalyst to make the product precipitate deeply, and then obtain it through deacidification, washing, fine boiling and drying.

2. After the refined short cotton linters are dried, they are activated with acetic acid, and then esterified with a mixture of acetic acid and acetic anhydride in the presence of sulfuric acid catalyst, which is 7 times the amount of the refined short cotton linters, to make them acetic. Then, dilute acetic acid is added to hydrolyze them to the required degree of hydrolysis (1.72-1.95). The catalyst is neutralized to precipitate the product, which is then deacidified, washed, cooked and dried to obtain cellulose acetate. During the acetylation reaction, by changing the amount of the added acetic acid and acetic anhydride mixture, diacetate cellulose and triacetate cellulose can be produced. The amount of the mixture of acetic acid and acetic anhydride is 8.5 times that of the refined short cotton linters. After the reaction, dilute acetic acid is added for hydrolysis to reach 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. After the reaction, it is hydrolyzed with dilute acetic acid to achieve a degree of substitution of 2.8 to 2.9 to obtain triacetate cellulose.