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Production method of cellulose acetate

A technology of cellulose acetate and production method, which is applied in the field of polymer chemistry, can solve problems such as uneven degree of esterification, low degree of esterification, and uneven activation of products, and achieve high degree of substitution, simple production process, and reaction The effect of shortening the time

Inactive Publication Date: 2012-08-29
LUZHOU NORTH CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are problems such as uneven activation in this method, resulting in uneven degree of esterification of the product, low degree of esterification, and low viscosity.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039]100 parts by weight of wood pulp was crushed into small pieces, 1000 parts by weight of glacial acetic acid was added, and soaked for 1 hour at 40°C. The temperature was lowered to 24°C, and 1 part by weight of 98% sulfuric acid was slowly added under stirring, followed by 300 parts by weight of acetic anhydride to carry out esterification. The temperature was controlled at 40° C., and the reaction was carried out for 4 hours. After the temperature of the esterification solution was lowered to 24° C., 100 parts by weight of 85% (mass percentage concentration) acetic acid aqueous solution was slowly added under the condition of rapid stirring. When the temperature no longer changes, continue to add 130 parts by weight of 10% (wt%) sodium acetate aqueous solution. After the addition was complete, the reaction temperature was controlled at 30° C., and the reaction was continued for 1.5 hours. Then the reacted slurry is filtered through a 500-mesh filter, and the filtered ...

Embodiment 2

[0042] Add 1200 parts by weight of glacial acetic acid to 100 parts by weight of wood pulp crushed into small pieces, and soak for 1 hour at 40°C. Cool down to 24°C, slowly add 0.8 parts by weight of 98% sulfuric acid with stirring, and then add 350 parts by weight of acetic anhydride to carry out esterification. The temperature was controlled at 40° C., and the reaction was carried out for 4 hours. The temperature of the esterification solution was lowered to 24° C., and then slowly added 120 parts by weight of 85% (mass percent concentration) acetic acid aqueous solution under the condition of rapid stirring. When the temperature no longer changes, continue to add 140 parts by weight of 10% (wt%) sodium acetate aqueous solution. After the addition was complete, the reaction temperature was controlled at 30° C., and the reaction was continued for 1.5 hours. Then the reacted slurry is filtered through an 800-mesh filter, and the filtered slurry is passed into a 10% aqueous s...

Embodiment 3

[0045] Add 1800 parts by weight of glacial acetic acid to 100 parts by weight of wood pulp crushed into small pieces, and soak for 3 hours at 20°C. 4 parts by weight of 98% sulfuric acid were added with stirring, and then 550 parts by weight of acetic anhydride was added to carry out esterification. The temperature was controlled at 50° C., and the reaction was carried out for 8 hours. The temperature of the esterification solution was lowered to 12° C., and then slowly added 150 parts by weight of 87% (mass percent concentration) acetic acid aqueous solution under the condition of rapid stirring. When the temperature no longer changes, continue to add 150 parts by weight of 5% (wt%) sodium acetate aqueous solution. After the addition was complete, the reaction temperature was controlled at 50° C., and the reaction was continued for 3 hours. Then the reacted slurry is filtered through an 800-mesh filter, and the filtered slurry is passed into 5% acetic acid aqueous solution ...

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Abstract

The invention belongs to the field of polymer chemistry, and relates to a preparation method of cellulose acetate. The cellulose acetate obtained by the method has low turbidity and high viscosity. The method comprises the following steps of: A, activating 1 weight part of cellulose by using 8 to 20 weight parts of glacial acetic acid at the temperature of between 20 and 60 DEG C; B, adding 0.005to 0.05 weight part of catalyst and 3 to 6 weight parts of acetic anhydride; C, adding 0.5 to 1.5 weight parts of high-concentration acetic acid solution at the temperature of between 10 and 25 DEG C, and reacting till the content of the acetic acid is 60.5 to 62.5 percent, wherein the high-concentration acetic acid solution is 80 mass percent acetic acid; D, adding 0.5 to 1.5 weight part of 5 to15 weight percent aqueous solution of acetate, and reacting for 1 to 3 hours at the temperature of between 20 and 50 DEG C; and E, filtering, settling and granulating. The preparation method is simple and convenient in the production process and easy in operation; the reaction time is shortened; the prepared product has high substitution degree, namely the content of the acetic acid is more than or equal to 60.0 percent; the product has high viscosity, namely the falling ball viscosity is more than or equal to 70 seconds; and the cellulose acetate is particularly suitable for manufacturing polarizing films in optical elements.

Description

technical field [0001] The invention belongs to the technical field of polymer chemistry, in particular to a production method of cellulose acetate. Background technique [0002] Cellulose acetate (Cellulose Acetate referred to as CA) is a cellulose ester obtained by acetylating natural cellulose, and is an extremely important organic acid ester of cellulose. According to its degree of esterification, it can be divided into several grades. The degree of esterification is between 2 and 3, and the amount of combined acetic acid is 48.5 to 58.8%. %, called tri-cellulose acetate (Tri-cellulose Acetate, referred to as TCA). [0003] As a photographic material, a film of cellulose triacetate has been widely used. And because triacetate cellulose film has excellent smoothness and optical anisotropy, it is also used in the manufacture of liquid crystal displays or LCDs. On liquid crystal display devices, cellulose triacetate films are used as protective films for polarizers or c...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08B3/06
Inventor 唐纹涛谭敏龚增培吕玉山张仕明田径张涛
Owner LUZHOU NORTH CHEM IND
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