Water-decomposable fibrous sheet containing water-insoluble carboxymethyl cellulose

• US 6,547,927 B1
• Filed: 09/18/2000
• Issued: 04/15/2003
• Est. Priority Date: 09/30/1999
• Status: Expired due to Term

• Current Assignee: Unicharm Corporation
• Original Assignee: Unicharm Corporation
• Inventors: Konishi, Takayoshi, Takeuchi, Naohito, Shimizu, Jyoji
• Primary Examiner(s): Griffin, Steven P.
• Assistant Examiner(s): HALPERN, MARK
• Application Number:
  US09/664,231
• Time in Patent Office: 939 Days
• Field of Search: 162/115, 162/141, 162/146, 162/149, 162/158, 162/177, 162/181.1, 162/181.2, 162/183, 428/152, 428/154, 428/198, 442/311
• US Class Current: 162/115
• CPC Class Codes: D21H 17/26 Ethers thereof
• CPC Class Codes: Y10T 428/24446 Wrinkled, creased, crinkled or creped
• CPC Class Codes: Y10T 428/24463 Plural paper components

Abstract

There is disclosed a water-decomposable fibrous sheet including water-dispersible fibers and water-insoluble carboxymethyl cellulose. The water-insoluble carboxymethyl cellulose has a degree of substitution for etherification (DE) falling between 0.3 and 0.6. In the water-insoluble carboxymethyl cellulose, the hydrogen of the carboxyl group in at least 95% of the carboxymethyl groups is substituted with a metal.

Claims

1. A water-decomposable fibrous sheet comprising water-dispersible fibers and water-insoluble carboxymethyl cellulose, wherein;

the water-insoluble carboxymethyl cellulose has a degree of substitution for etherification (DE) falling between 0.3 and 0.6, and, in the water-insoluble carboxymethyl cellulose, the hydrogen of the carboxyl group in at least 95% of the carboxymethyl groups is substituted with a metal;

and wherein the water-decomposable fibrous sheet has a degree of decomposition in water of at most 100 seconds measured when wet, a strength at breakage when dry of at least 1000 g/25 mm, and a strength at breakage when wet of at least 100 g/25 mm.

2. The water-decomposable fibrous sheet as set forth in claim 1, wherein the metal is at least one selected from the group consisting of calcium, sodium, magnesium, zinc, manganese, lithium, barium and aluminium.

3. The water-decomposable fibrous sheet as set forth in claim 1, which has a basis weight falling between 30 and 80 g/m².

4. The water-decomposable fibrous sheet as set forth in claim 3, of which the water-insoluble carboxymethyl cellulose content falls between 0.5 and 10% by weight.

5. The water-decomposable fibrous sheet as set forth in claim 3, which has a thickness of at least 0.1 mm.

6. The water-decomposable fibrous sheet as set forth in claim 1, which is a water-decomposable non-woven fabric having been subjected to water-jetting treatment.

7. The water-decomposable fibrous sheet as set forth in claim 1, which is water-decomposable paper having been prepared in a paper-making process.

8. The water-decomposable fibrous sheet as set forth in claim 1, wherein the water-dispersible fibers are fibers of at least one type selected from group consisting of pulp, regenerated cellulose, Manila hemp, and linter pulp.