US4735987A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for manufacture of high-expansion type absorbent polymer
Assignee: Osaka Yuki Kagaku Kogyo KK
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Filing: 1986-06-30
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Granted: 1988-04-05
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Expires: 2006-06-30
Abstract
Abstract This invention provides a method for the manufacture of a high-expansion type absorbent polymer by first causing an absorbent polymer which is obtained by polymerization of a monomer and is possessed of an alkali salt of acrylic acid as a component of polymer to be cross-linked at the time of azeotropic dehydration thereof with a cross-linking agent possessing two or more functional groups in the presence of an inorganic salt and subsequently drying the cross-linked polymer. By the method of this invention, there can be obtained a high-expansion type absorbent material which absorbs water quickly and forms a gel not viscid but permeable to gas. This absorbent material is highly advantageously used as absorbent for sanitary materials free from leaking water and as a water-retaining agent for agricultural applications hardly causing rotton plant roots.
Inventors
- 👤 Yasuhiro Morita
- 👤 Takanori Iwamoto
- 👤 Hiroyuki Kataoka
- 👤 Taiji Kambayashi
- 👤 Shigeaki Matsumoto
- 👤 Chuzo Kato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:52
CPC Classifications
C; C08; C08F; C08F20/00; C08F20/02; C08F20/04; C08F20/06; A; A61; A61L; A61L15/00; A61L15/16; A61L15/18; A61L15/42; A61L15/60; B; B01; B01J; B01J20/00; B01J20/22; B01J20/26
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
150 words
A method for the manufacture of a high-expansion type absorbent polymeric powder which forms a non-viscid, gas-permeable gel in the presence of water, comprising: (a) partially neutralizing an aqueous solution of an acrylic acid with an alkali hydroxide to obtain at least 75 mol % of an alkali salt of an acrylic acid; (b) adding said solution of partially neutralized acid to a suspension of a water-soluble cross-linking agent which is used in an amount of 0.05 to 2% by weight based on said monomer, in an aliphatic hydrocarbon solvent containing a small amount of water and a surfactant; (c) partially polymerizing the monomer at at an elevated temperature; (d) adding to said partially polymerized mixture a lamellar mineral inorganic substance in an amount of 0.5 to 30% by weight based on said monomer; (e) azeotropically distilling away said hydrocarbon and said water; and (f) drying the powder thus obtained.
Claim 2
Independent Claim
150 words
A method for the manufacture of a high-expansion type absorbent polymeric powder which forms a non-viscid, gas-permeable gel in the presence of water, comprising: (a) partially neutralizing an aqueous solution of an acrylic acid with an alkali hydroxide to obtain at least 75 mol % of an alkali salt of an acrylic acid; (b) adding said solution of partially neutralized acid to a suspension of a water-soluble cross-linking agent which is used in an amount of 0.05 to 2% by weight based on said monomer, in an aliphatic hydrocarbon solvent containing a small amount of water and a surfactant; (c) partially polymerizing the monomer at at an elevated temperature; (d) adding to said partially polymerized mixture a lamellar mineral inorganic substance in an amount of 0.5 to 30% by weight based on said monomer; (e) azeotropically distilling away said hydrocarbon and said water; and (f) drying the powder thus obtained.
Claim 3
Dependent Claim
19 words
A method according to claim 1, wherein said inorganic substance is a binary metal hydroxide possessing an anion-exchange capacity.
Claim 4
Dependent Claim
17 words
A method according to claim 2, wherein said binary metal hydroxide possessing an anion-exchange capacity is hydrotalcite.
Claim 5
Dependent Claim
21 words
A method according to claim 1, wherein said inorganic substance is a natural or synthetic laminar clay mineral possessing cation-exchange capacity.
Claim 6
Dependent Claim
20 words
A method according to claim 1 or 2, wherein said inorganic substance is montmorillonite or montmorillonite treated with an acid.
Claim 7
Dependent Claim
19 words
A method according to claim 1, wherein said inorganic substance is talc, pyrophyllite, or kaolinite possessing a lamellar construction.
Claim 8
Dependent Claim
15 words
A method according to claim 1, wherein said cross-linking agent is ethylene glycol diglycidyl ether.
Claim 9
Dependent Claim
21 words
The method of manufacture according to claim 1 further comprising a monomer which is co-polymerizable with acrylic acids and salts thereof.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-04-05 | 1991-10-05 | 1992-04-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-05 | 1995-10-05 | 1996-04-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-05 | 1999-10-05 | 2000-04-05 | $7700.00 | Window Closed / Lapsed |