Preparation method of cellulose acetate

A technology of cellulose acetate and acetate, applied in the field of polymer chemistry, can solve the problems of low degree of esterification, low viscosity, uneven activation, etc. Effect

Inactive Publication Date: 2011-08-17
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 l

[0033] 1, the cellulose of 1 weight part is activated 1h at 40 ℃ with glacial acetic acid, and the weight ratio of cellulose and glacial acetic acid is 1: 10, and cellulose refers to wood pulp.

[0034] 2, during the esterification process, directly utilize the acetic acid in the activation process as a solvent, add 98% sulfuric acid earlier, and the consumption is 0.5% of the cellulose weight. Then add acetic anhydride as the reaction solution to fully acetylate the cellulose, and the dosage is 4.5 times that of the cellulose. The esterification temperature is 40°C, and the esterification time is 3.5h.

[0035] 3. 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 weight ratio of cellulose to hydrolyzate is 1:1. The hydrolysis time is 1.5 hours, so that the acetic acid content of the cellulose acetate is between 60.5-62....

Embodiment 2

[0039] 1. 1 part by weight of cellulose is activated with glacial acetic acid for 1.5 h at 35° C., the weight ratio of cellulose to glacial acetic acid is 1:15, and cellulose refers to cotton pulp.

[0040] 2, during the esterification process, directly utilize the acetic acid in the activation process as solvent, add catalyzer earlier, consumption is 0.65% of cellulose weight, and catalyzer refers to 98% sulfuric acid. Then add acetic anhydride as a reaction solution to fully acetylate the cellulose, and the dosage is 4 times that of the cellulose. The esterification temperature is 35°C, and the esterification time is 4h.

[0041] 3. For hydrolysis, the temperature of the esterification liquid is required to be 20° C., and the hydrolyzed liquid is 75% (mass percentage concentration) acetic acid, which is slowly added while stirring. The weight ratio of cellulose to hydrolyzate is 1:1.2. The hydrolysis time is 1.2 hours, so that the acetic acid content of cellulose acetate i...

Embodiment 3

[0044] 1. 1 part by weight of cellulose is activated with glacial acetic acid at 55° C. for 1.5 h, the weight ratio of cellulose to glacial acetic acid is 1:8, and cellulose refers to cotton pulp.

[0045] 2, during the esterification process, directly utilize the acetic acid in the activation process as solvent, add catalyzer earlier, consumption is 0.65% of cellulose weight, and catalyzer refers to 98% sulfuric acid. Then add acetic anhydride as a reaction solution to fully acetylate the cellulose, and the dosage is 6 times that of the cellulose. The esterification temperature is 55°C, and the esterification time is 3h.

[0046] 3. 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 weight ratio of cellulose to hydrolyzate is 1:1.1. The hydrolysis time is 1.2 hours, so that the acetic acid content of cellulose acetate is...

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PUM

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Abstract

The invention belongs to the field of high polymer chemistry, and relates to a preparation method of cellulose acetate. The product obtained by the method provided by the invention has the advantages of high degree of substitution and high viscosity. The method comprises the following steps: A. soaking 1 part by weight of cellulose with 8-20 parts by weight of glacial acetic acid at 20-60 DEG C; B. esterifying at 20-58 DEG C for 3-8 hours by adding 4-6 parts by weight of acetic anhydride and 0.005-0.05 part by weight of catalyst; C. adding 0.5-1.5 parts by weight of 60-80% acetic acid at 15-25 DEG C, and reacting until the content of acetic acid in the cellulose acetate reaches 60.5-62.5%; D. adding 1.1-1.5 parts by weight of 5-15% acetate water solution, and reacting at 20-50 DEG C for 1-3 hours; and E. filtering, settling and granulating. The product obtained according to the invention has the advantages of high degree of substitution (the content of acetic acid in the product is higher than or equal to 60.0%) and high viscosity (the falling ball viscosity is higher than or equal to 70 seconds). The method provided by the invention increases the consumption of acetates for neutralization, effectively removes sulfates and enhances the heat resistance of the cellulose triacetate film.

Description

technical field [0001] The invention belongs to the technical field of polymer chemistry, in particular to a preparation 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 ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08B3/06C08B3/24
Inventor 唐纹涛龚增培张仕明田径张涛王建和刘江新
Owner LUZHOU NORTH CHEM IND
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