Self-cross-linked alkyl cellulose and processes for producing the same
View Patent ↗A process for producing a self-cross-linking alkyl cellulose derivative, which includes irradiating, with radioactive rays, a mixture of a starting alkyl cellulose derivative (the number of carbon atoms of the alkyl group is 1 through 3, the alkyl group may be substituted by a hydroxyl group or a carboxyl group, and the carboxyl group may form a salt) (100 parts by weight) and water (5-2,000 parts by weight), and thus obtained self-cross-linking alkyl cellulose derivative has an improved biodegradability and excellent water-absorbability.
1. A process for producing a self-cross-linked alkyl cellulose, which comprises irradiating, with radioactive rays, a mixture of 100 parts by weight of an alkyl cellulose wherein the alkyl group has 1 to 3 carbon atoms, and at least a part of the alkyl group is substituted by a carboxyl group, and wherein the carboxyl group may be in the form of a salt, and 5 to 2,000 parts by weight of water.
2. A process for producing a self-cross-linked alkyl cellulose, according to claim 1 , wherein the alkyl cellulose is carboxyalkyl cellulose, hydroxyalkyl cellulose, or alkyl cellulose, having at least one carboxyl group per glucose unit of the alkyl cellulose, or a mixture of these alkyl celluloses.
3. A process for producing a self-cross-linked alkyl cellulose, according to claim 1 , wherein 20% or more of the entirety of carboxyl groups of the alkyl cellulose is in the form of an alkali metal salt, an ammonium salt, or an amine salt.
4. A process for producing a self-cross-linked alkyl cellulose, according to claim 2 , wherein the alkyl cellulose has an average polymerization degree of 10 to 2,000 and an average etherification degree of 0.5 or more.
5. A process for producing a self-cross-linked alkyl cellulose, according to claim 1 , wherein the self-cross-linked alkyl cellulose has a gel fraction of 0.1% or more.
6. A process for producing a self-cross-linked alkyl cellulose, according to claim 1 , wherein the dose of radioactive rays is 0.1 kGy or more.
7. A process for producing a self-cross-linked alkyl cellulose, according to claim 1 , which further comprises drying the self-cross-linked cellulose.
8. A process for producing a self-cross-linked alkyl cellulose, which comprises irradiating, with radioactive rays, a mixture of 100 parts by weight of an alkyl cellulose wherein the alkyl group has 1 to 3 carbon atoms, and is substituted by a carboxyl group, and wherein the carboxyl group may be in the form of a salt, and 5 to 2,000 parts by weight of water so as to produce a self-cross-linked alkyl cellulose having a gel fraction of 0.1 to 30%, wherein the self-cross-linked alkyl cellulose, after drying, absorbs 20 times or more its weight in water.
9. A process for producing a self-cross-linked alkyl cellulose, which comprises irradiating, with radioactive rays, a mixture of 100 parts by weight of an alkyl cellulose wherein the alkyl group has 1 to 3 carbon atoms, and is substituted by a carboxyl group, and wherein the carboxyl group may be in the form of a salt, and 5 to 2,000 parts by weight of water so as to produce a self-cross-linked alkyl cellulose having a gel fraction of 30% or more and a compressive strength of 100 g/cm 2 or more.
10. A process according to claim 8 or 9 , wherein the alkyl cellulose is carboxyalkyl cellulose having at least one carboxyl group per glucose unit thereof.
11. A process according to claim 8 or 9 , wherein 20% or more of the entirety of carboxyl groups of the alkyl cellulose is in the form of an alkali metal salt, an ammonium salt, or an amine salt.
12. A process according to claim 8 or 9 , wherein the alkyl cellulose has an average polymerization degree of 10 to 2,000 and an average etherification degree of 0.5 or more.
13. A process according to claim 8 or 9 , wherein the self-cross-linked alkyl cellulose has a gel fraction of 0.1% or more.
14. A process for producing a self-cross-linked alkyl cellulose, which comprises irradiating, with radioactive rays, a mixture of 100 parts by weight of an alkyl cellulose wherein the alkyl group has 1 to 3 carbon atoms, and may be substituted by a hydroxyl group, and 5 to 233 parts by weight of water.
15. A process for producing a self-cross-linked alkyl cellulose, according to claim 14 , wherein the alkyl cellulose is hydroxyalkyl cellulose, alkyl cellulose having at least one hydroxyl group per glucose unit of the alkyl cellulose, or a mixture of these celluloses.
16. A process for producing a self-cross-linked alkyl cellulose, according to claim 15 , wherein the alkyl cellulose has an average polymerization degree of 10 to 2,000 and an average etherification degree of 0.5 or more.
17. A process for producing a self-cross-linked alkyl cellulose, according to claim 14 , wherein the self-cross-linked alkyl cellulose has a gel fraction of 0.1% or more.
18. A process for producing a self-cross-linked alkyl cellulose, according to claim 14 , wherein the dose of radioactive rays is 0.1 kGy or more.
19. A process for producing a self-cross-linked alkyl cellulose, according to claim 14 , which further comprises drying the self-cross-linked cellulose.
20. A process for producing a self-cross-linked alkyl cellulose, which comprises irradiating, with radioactive rays, a mixture of 100 parts by weight of an alkyl cellulose wherein the alkyl group has 1 to 3 carbon atoms, and may be substituted by a hydroxyl group, and 5 to 233 parts by weight of water so as to produce a self-cross-linked alkyl cellulose having a gel fraction of 0.1 to 30%, wherein the self-cross-linked alkyl cellulose, after drying, absorbs 20 times or more its weight in water.
21. A process for producing a self-cross-linked alkyl cellulose, which comprises irradiating, with radioactive rays, a mixture of 100 parts by weight of an alkyl cellulose wherein the alkyl group has 1 to 3 carbon atoms, and may be substituted by a hydroxyl group, and 5 to 233 parts by weight of water so as to produce a self-cross-linked alkyl cellulose having a gel fraction of 30% or more and a compressive strength of 100 g/cm 2 or more.
22. A process according to claim 20 or 21 , wherein the alkyl cellulose is hydroxyalkyl cellulose, or an alkyl cellulose having at least one hydroxyl group per glucose unit, or a mixture of these celluloses.
23. A process according to claim 20 or 21 , wherein the alkyl cellulose has an average polymerization degree of 10 to 2,000 and an average etherification degree of 0.5 or more.
24. A process according to claim 20 or 21 , wherein the self-cross-linked alkyl cellulose has a gel fraction of 0.1% or more.