Method for producing cellulose

Patent metadata

Field	Value
Publication number	US-2016244913-A1
Application number	US-201414913854-A
Country	US
Kind code	A1
Filing date	Aug 25, 2014
Priority date	Sep 12, 2013
Publication date	Aug 25, 2016
Grant date	—

Abstract

The process of the present invention for preparation of cellulose uses:
chemical pulp; and a mixed solution containing 1.0% to 30.0% by weight of sulfuric acid, 0.5% to 40% by weight of hydrogen peroxide and 50.0% to 94.0% by weight of water, wherein the resulting cellulose has a polymerization degree of 350 or less and a brightness by Hunter of 90% or more.

First claim

1 . A process for preparing a cellulose, using:
a chemical pulp; and a mixed solution containing 1.0% to 30.0% by weight of a sulfuric acid, 0.5% to 40% by weight of a hydrogen peroxide and 50.0% to 94.0% by weight of a water, wherein the cellulose has a polymerization degree of 350 or less and a brightness by Hunter of 90% or more.

2 . The process according to claim 1 , wherein
the mixed solution has a mix ratio of the sulfuric acid (x), the hydrogen peroxide (y) and the water (z), which is expressed by (x, y, z), the (x, y, z) has a value present on a line or inside of a heptagon ABCDEFG, and the heptagon ABCDEFG is formed by vertices A to G having the following (x, y, z) in a ternary diagram for the sulfuric acid (x)-hydrogen peroxide (y)-water (z): A (3.0, 3.0, 94.0) B (7.0, 0.5, 92.5) C (24.0, 0.5, 75.5) D (30.0, 3.0, 67.0) E (30.0, 10.0, 60.0) F (10.0, 40.0, 50.0) G (1.0, 24.0, 75.0)
(wherein x, y and z each represent a ratio by weight, and x+y+z=100).

3 . The process according to claim 2 , wherein the mix ratio (x, y, z) has
a value present on a line or inside of a heptagon HICDEFG, provided that:
the vertex A is replaced with a vertex H (3.0, 9.0, 88.0); and
the vertex B is replaced with a vertex I (6.0, 2.0, 92.0).

4 . The process according to claim 2 , wherein the mix ratio (x, y, z) has
a value present on a line or inside of a heptagon JKCDEFG, provided that:
the vertex A is replaced with a vertex J (6.0, 9.0, 85.0); and
the vertex B is replaced with a vertex K (12.0, 3.0, 85.0).

5 . The process according to claim 1 , comprising:
mixing the sulfuric acid, the hydrogen peroxide and the water to prepare the mixed solution; and soaking the chemical pulp in the mixed solution.

6 . The process according to claim 1 , wherein a reaction temperature of the chemical pulp and the mixed solution is 60° C. to 110° C.

7 . The process according to claim 5 , wherein the mixed solution is prepared by adding the sulfuric acid and the hydrogen peroxide to the water.

8 . The process according to claim 5 , wherein the mixed solution is prepared by mixing the sulfuric acid, an aqueous hydrogen peroxide having a concentration of less than 50% by weight, and the water.

9 . The process according to claim 1 , wherein the mixed solution contains a peroxymonosulfuric acid in a concentration of 0.01% to 25% by weight in the mixed solution.

10 . The process according to claim 9 , wherein the concentration of the peroxymonosulfuric acid in the mixed solution is equal to or less than a concentration of the peroxymonosulfuric acid in an equilibrium solution containing a sulfuric acid, a hydrogen peroxide and a water.

11 . The process according to claim 10 , wherein the concentration of the peroxymonosulfuric acid in the mixed solution is 0.01% to 17.1% by weight.

12 . Cellulose prepared by the process according to claim 1 , having a polymerization degree of 350 or less and a brightness by Hunter of 90% or more.

Assignees

• Mitsubishi Gas Chemical Co

Inventors

• Tsuruga Takamitsu
• OYANAGI Kenji
• Hamaguchi Takayoshi

Classifications

• D21C9/163

  with peroxides · CPC title

• D21C3/06 Primary

  sulfur dioxide; sulfurous acid; bisulfites {sulfites} · CPC title

• D21C3/04

  with acids, acid salts or acid anhydrides {(D21C3/003 and D21C3/222 take precedence)} · CPC title

• C08B15/00 Primary

  Preparation of other cellulose derivatives or modified cellulose {, e.g. complexes} · CPC title