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Process for producing cellulose acetate

A technology of cellulose acetate and production process, which is applied in the field of polymer chemistry, can solve the problems of low product transparency, and achieve the effects of facilitating coating operation, good casting, and preventing degradation

Inactive Publication Date: 2013-01-02
LUZHOU NORTH CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method has problems such as low product transparency

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] 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. Cool down to 24°C, slowly add 1 part by weight of 98% sulfuric acid with stirring, and then add 400 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.

[0036] For hydrolysis, the temperature of the esterification liquid is required to be 25° C., and the hydrolyzed liquid is 80% (mass percentage concentration) acetic acid, which is slowly added while stirring. The purpose is to react excess acetic anhydride to ensure the homogeneity of cellulose acetate. The mass ratio of cellulose to hydrolyzate is 1:1.2. The hydrolysis time is 1.5 hours, so that the acetic acid content of cellulose acetate is between 60.5-62.5%,

[0037] When the temperature does not change any more, continue to add 10% (wt%) sodium acetate aqueous so...

Embodiment 2

[0041] 100 parts by weight of cotton pulp was crushed into small pieces, 1000 parts by weight of glacial acetic acid was added, and soaked for 1 hour at 35°C. The temperature was lowered to 20°C, and 0.5 parts by weight of 98% sulfuric acid was slowly added under stirring, followed by 600 parts by weight of acetic anhydride for esterification. The temperature was controlled at 35° C., and the reaction was carried out for 5 hours.

[0042] For hydrolysis, the temperature of the esterification liquid is required to be 25° C., and the hydrolyzed liquid is 75% (mass percentage concentration) acetic acid, which is slowly added while stirring. The purpose is to react excess acetic anhydride to ensure the homogeneity of cellulose acetate. The mass ratio of cellulose to hydrolyzate is 1:1.5. The hydrolysis time is 1.5 hours, so that the acetic acid content of cellulose acetate is between 60.5-62.5%,

[0043] When the temperature does not change any more, continue to add 10% (wt%) s...

Embodiment 3

[0045] 100 parts by weight of cotton pulp was crushed into small pieces, 1800 parts by weight of glacial acetic acid was added, and soaked for 1 hour at 25°C. Cool down to 20°C, slowly add 4 parts by weight of 98% sulfuric acid with stirring, and then add 500 parts by weight of acetic anhydride to carry out esterification. The temperature was controlled at 20° C., and the reaction was carried out for 3 hours.

[0046] For hydrolysis, the temperature of the esterification liquid is required to be 15° C., and the hydrolyzed liquid is 65% (mass percentage concentration) acetic acid, which is slowly added while stirring. The purpose is to react excess acetic anhydride to ensure the homogeneity of cellulose acetate. The mass ratio of cellulose to hydrolyzate is 1:1.5. The hydrolysis time is 1.5 hours, so that the acetic acid content of cellulose acetate is between 60.5-62.5%,

[0047] When the temperature does not change anymore, continue to add 5% (wt%) sodium acetate aqueous s...

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Abstract

The invention belongs to the field of the polymer chemistry and particularly relates to a process for producing cellulose acetate, and has the advantages of easiness for operation and high degree of substitution and high viscosity of a product. The process for producing cellulose acetate comprises the following steps: A, activating 1 part by weight of cellulose by using 8-20 parts by weight of glacial acetic acid at 20-60 DEG C; B, adding 4-6 parts by weight of acetic anhydride and 0.005-0.05 part by weight of catalyst to carry out esterification for 3-8 hours at 20-58 DEG C; C, adding 1.1-1.5 parts by weight of 60-80% acetic acid at 10-25 DEG C to carry out hydrolysis reaction for 0.5 2 hours until the content of the acetic acid reaches 60.5-62.5%; D, adding 0.5-1.5 parts by weight of 5-15% aqueous acetate solution; E, carrying out a reaction on the materials for 15-45 minutes at normal temperature; and F, filtering, precipitating and granulating to obtain the cellulose acetate. The cellulose acetate produced by adopting the process contains 60.0% of acetic acid or more, has good flow ductility when being used for producing a polarization film and is applicable to the production of a polarization film for the optical element.

Description

technical field [0001] The invention belongs to the technical field of macromolecule chemistry, in particular to a production process 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 polarize...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08B3/06C08B3/24G02B1/04G02B5/30
Inventor 谭敏唐纹涛张仕明吕玉山田径张涛王建和
Owner LUZHOU NORTH CHEM IND