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Methods for producing alkali cellulose and cellulose ether

一种碱纤维素、碱金属的技术，应用在生产纤维素醚领域，能够解决碱纤维素均匀性不足等问题，达到生产高的效果

Active Publication Date: 2012-08-22
SHIN ETSU CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Insufficient uniformity of alkali cellulose directly leads to insoluble fraction

Method used

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  • Methods for producing alkali cellulose and cellulose ether
  • Methods for producing alkali cellulose and cellulose ether
  • Methods for producing alkali cellulose and cellulose ether

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0065] The pulp A sheet and the pulp B sheet were laminated and processed together with a cutter to produce mixed pulp chips AB of 10 mm2.

[0066]A screw conveyor type immersion tank including a screw conveyor with a screw diameter of 154 mm, a shaft diameter of 90 mm, a screw length of 1,500 mm, and a pitch of 100 mm was provided and the screw conveyor was rotated at 25 rpm. The mixed pulp chips AB were fed at a rate of 50 kg / hour into a screw conveying type immersion tank. Simultaneously, a 30° C. 49% by weight aqueous sodium hydroxide solution was fed into the tank at a rate of 1,700 L / hour from the sodium hydroxide inlet. An extruded plate type centrifugal dehydrator (which is a continuous centrifugal separator) with a 0.2 mm slit screen was installed at the end of the screw conveying type immersion tank. The centrifugal dehydrator deliquored the contact mixture between the mixed pulp chips and the aqueous sodium hydroxide solution, which had been discharged from the scr...

Embodiment 2

[0069] Pulp C and pulp D were used as raw materials. The ratio of the absorption rates of the aqueous sodium hydroxide solution of pulp D to pulp C (pulp D / pulp C) was 2.00.

[0070] Pulp C sheets and pulp D sheets were laminated and processed together with a cutter to produce mixed pulp chips CD of 10 mm2.

[0071] A tube having an inner diameter of 38 mm and a length of 10 m was provided and connected to a serpentine pump equipped with a hopper (Heishin Pump Works Co., Ltd., model NVL40PL) at the tube inlet. A 49% by weight aqueous sodium hydroxide solution at 40° C. was fed to the hopper at a rate of 1,100 L / h. At the same time, mixed pulp chips CD were fed at a rate of 50 kg / h. Connect the tube to the V-disc press at the end of the tube. The V-disk press continuously deliquors the contact mixture between the mixed pulp crumb and aqueous sodium hydroxide solution, which has been discharged from the pipe. The weight ratio of the alkali metal hydroxide in the resulting al...

Embodiment 3

[0074] Pulp E and pulp F were used as raw materials. The ratio of the absorption rates of the aqueous sodium hydroxide solution of pulp F to pulp E (pulp F / pulp E) was 4.00.

[0075] Pulp E sheets and pulp F sheets were laminated and processed together with a cutter to produce mixed pulp chips EF of 10 mm2.

[0076] A screw conveyor type immersion tank including a screw conveyor with a screw diameter of 154 mm, a shaft diameter of 90 mm, a screw length of 1,500 mm, and a pitch of 100 mm was provided and the screw conveyor was rotated at 30 rpm. The mixed pulp chips EF were fed at a rate of 50 kg / hour into a screw conveying type immersion tank. Simultaneously, a 49% by weight aqueous sodium hydroxide solution at 20° C. was fed into the tank at a rate of 1,700 L / hour from the sodium hydroxide inlet. An extruded plate type centrifugal dehydrator (which is a continuous centrifugal separator) with a 0.2 mm slit screen was installed at the end of the screw conveying type immersion...

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Abstract

When a combination of pulps having different alkali metal hydroxide solution absorption rates is as a raw material, contact conditions such as a contact temperature and a contact time have to be changed frequently, depending on the absorption rate of pulps currently processed, thereby causing a problem of reduced productivity. For solving the problem, provided is a method for producing alkali cellulose, comprising at least the steps of: bringing two or more types of pulps having different alkali metal hydroxide solution absorption rates into contact with an alkali metal hydroxide solution to obtain a contact product; and draining the contact product, wherein the highest absorption rate is not more than 4.0 times as fast as the lowest absorption rate.

Description

technical field [0001] The present invention relates to a method for producing alkali cellulose and a method for producing cellulose ether by using the alkali cellulose. Background technique [0002] As for the production of cellulose ethers, a method of contacting an alkaline solution with highly purified pulp to produce the corresponding alkali cellulose and etherifying the resulting alkali cellulose with an etherifying agent is known. By properly controlling its degree of substitution, the cellulose ether obtained as the final product becomes water-soluble. Water-soluble cellulose ethers contain water-insoluble parts that sometimes lower the transmittance of an aqueous cellulose ether solution or impair the commercial value of the cellulose ether as a contaminant. This insoluble part seems to be caused by the presence of a low-substituted part which does not have enough substituents to be soluble in water. One reason why there is an insoluble fraction is that the alkali...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08B1/08C08B11/00
CPCC08B1/08C08B11/00C08B11/193
Inventor 成田光男
Owner SHIN ETSU CHEM CO LTD
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