US3932574A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing fibrous polyvinyl alcohol
Assignee: Kuraray Co Ltd
•
Filing: 1973-07-11
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Granted: 1976-01-13
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Expires: 1993-07-11
Abstract
Abstract Shaped articles of polyvinyl alcohol are prepared by saponifying a liquid feed of polyvinyl ester as it cascades downwardly along the walls of a cylindrical reactor, and by taking-up from the reactor outlet the fibrous, shaped article of oriented, solid polyvinyl alcohol thus formed at a rate of at least 50 cm/minute. Advantageously, the thus formed shaped article is next divided into sliver, stretched and cut into fibers and, optionally, beaten, which fibers are useful in the manufacture of paper-like sheet materials.
Inventors
- 👤 Makoto Shiraishi
- 👤 Sigetaka Iwata
- 👤 Masao Oura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:19
CPC Classifications
D; D01; D01F; D01F6/00; D01F6/02; D01F6/14; C; C08; C08F; C08F8/00; C08F8/12; D01D; D01D5/00; D21; D21H; D21H13/00; D21H13/10; D21H13/12; D21H13/16; Y; Y10; Y10S; Y10S264/00; Y10S264/47
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
108 words
A process for the preparation of shaped articles of polyvinyl alcohol, comprising saponifying a liquid feed of a polyvinyl ester as same downwardly cascades through a horizontal hollow cylindrical reactor, and thence taking-up from the reactor outlet the fibrous, shaped article of oriented, solid polyvinyl alcohol thus formed at a rate of from 50 to 1,500 cm/minute in the form of a continuous bar, wetting said bar with a non- or poor solvent for polyvinyl alcohol until same contains at least 25% by weight of volatile components and wet-stretching said bar at a temperature of from 50° to 200°C. whereby said bar is transformed into fibrous polyvinyl alcohol.
Claim 2
Dependent Claim
108 words
A process for the preparation of shaped articles of polyvinyl alcohol, comprising saponifying a liquid feed of a polyvinyl ester as same downwardly cascades through a horizontal hollow cylindrical reactor, and thence taking-up from the reactor outlet the fibrous, shaped article of oriented, solid polyvinyl alcohol thus formed at a rate of from 50 to 1,500 cm/minute in the form of a continuous bar, wetting said bar with a non- or poor solvent for polyvinyl alcohol until same contains at least 25% by weight of volatile components and wet-stretching said bar at a temperature of from 50° to 200°C. whereby said bar is transformed into fibrous polyvinyl alcohol.
Claim 3
Dependent Claim
25 words
The process as defined by claim 1, wherein the liquid feed of polyvinyl ester comprises an alcoholic solution of polyvinyl acetate and a saponification catalyst.
Claim 4
Dependent Claim
22 words
The process as defined by claim 2, wherein the alcoholic solution is a methanolic solution and the catalyst is an alkali catalyst.
Claim 5
Dependent Claim
24 words
The process as defined by claim 3, wherein the concentration of polyvinyl acetate in the methanolic solution is greater than about 20% by weight.
Claim 6
Dependent Claim
18 words
The process as defined by claim 4, wherein the concentration is between about 20 and 40% by weight.
Claim 7
Dependent Claim
22 words
The process as defined by claim 4, wherein the degree of polymerization of the polyvinyl acetate ranges between about 1,000 and 3,000.
Claim 8
Dependent Claim
24 words
The process as defined by claim 4, wherein the saponification is effected at a temperature in the range of between about 35° and 55°C.
Claim 9
Dependent Claim
23 words
The process as defined by claim 4, wherein the mole ratio of catalyst to polyvinyl acetate ranges from between about 0.01 and 0.10.
Claim 10
Dependent Claim
26 words
The process as defined by claim 4, wherein the catalyst is present in an amount of between about 50 and 200 grams per liter of methanol.
Claim 11
Dependent Claim
31 words
The process as defined by claim 4, wherein the reactor has an internal diameter of between about 10 and 300 mm, and a length of between about 4,000 and 30,000 mm.
Claim 12
Dependent Claim
34 words
The process as defined by claim 4, wherein the feed further comprises an alcoholic solution of partially saponified polyvinyl ester having a molar percent of degree of saponification of between about 10 and 45.
Claim 13
Dependent Claim
33 words
The process as defined by claim 11, wherein the partially saponified polyvinyl ester is present in an amount from between about 20 and 75% by weight of the unsaponified polyvinyl acetate feed solution.
Claim 14
Dependent Claim
20 words
The process as defined by claim 4, further comprising dividing the shaped article of oriented, solid polyvinyl alcohol into sliver.
Claim 15
Dependent Claim
16 words
The process as defined by claim 13, further comprising stretching the filaments which comprise the sliver.
Claim 16
Dependent Claim
15 words
The process as defined by claim 14, wherein the filaments are both wet- and dry-stretched.
Claim 17
Dependent Claim
18 words
The process as defined by claim 15, wherein the filaments contain at least 25% volatiles during the wet-stretching.
Claim 18
Dependent Claim
32 words
The process as defined by claim 16, wherein the wet-stretching is effected at a temperature in the range of between about 50° and 200°C., and the filaments are drawn at least twofold.
Claim 19
Dependent Claim
32 words
The process as defined by claim 17, wherein the filaments are wet to a volatiles content of between about 25 and 85% by weight, and the wet-stretching is from three- to tenfold.
Claim 20
Dependent Claim
27 words
The process as defined by claim 18, wherein the filaments are further dried and stretched at a temperature in the range of between about 100° and 220°C.
Claim 21
Dependent Claim
22 words
The process as defined by claim 19, wherein the volatiles content of the filaments during dry-stretching is less than 10% by weight.
Claim 22
Dependent Claim
17 words
The process as defined by claim 20, further comprising washing the filaments with an aqueous, acidic solution.
Claim 23
Dependent Claim
16 words
The process as defined by claim 20, wherein the resultant, stretched filaments are cut into fibers.
Claim 24
Dependent Claim
20 words
The process as defined by claim 22, wherein the cut fibers are between about 1 and 50 mm in length.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-01-12 | 1979-07-14 | 1980-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-12 | 1983-07-14 | 1984-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-12 | 1987-07-14 | 1988-01-13 | $7700.00 | Window Closed / Lapsed |