Fluid-absorbing polymers, processes used in their production and their application

• US 5,837,789 A
• Filed: 11/20/1996
• Issued: 11/17/1998
• Est. Priority Date: 11/21/1995
• Status: Expired due to Term

• Current Assignee: Evonik Degussa GmbH
• Original Assignee: Stockhausen GmbH & Company Kg (Stockhausen Incorporated)
• Inventors: Pflueger, Klaus, Brehm, Helmut, Jonas, Gerd, Messner, Bernfried, Hartan, Hans-Georg, Stockhausen, Dolf
• Primary Examiner(s): Smith, Jeffrey T.
• Assistant Examiner(s): Cheng, Wu C.
• Application Number:
  US08/752,889
• Time in Patent Office: 727 Days
• Field of Search: 526/320, 526/329.6, 526/310, 526/306, 526/317.1, 526/303.1, 526/307.1, 526/264
• US Class Current: 526/320
• CPC Class Codes: A61L 15/60 Liquid-swellable gel-forming materials, e.g. super-absorbents
• CPC Class Codes: C08F 251/00 Macromolecular compounds obtained by polymerising monomers on to polysaccharides or derivatives thereof
• CPC Class Codes: C08F 261/04 on to polymers of vinyl alcohol
• CPC Class Codes: C08F 290/062 Polyethers
• CPC Class Codes: H01B 3/30 plastics; resins; waxes

Abstract

The present invention relates to superabsorbent cross-linked polymers for watery liquids, which are built-up of partially neutralized monomers having monoethylenlcally unsaturated acid groups, optionally further monomers copolymerizable therewith, as well as polymers optionally suitable as graft basis, and which can be manufactured by using a cross-linker/monomer combination of

CH.sub.2 ═CHR.sup.6 --CO--(OCHR.sup.3 --CHR.sup.3).sub.z O--CH.sub.2

--CHR⁶ ═CH₂

CH.sub.2 ═CHR.sup.6 --R.sup.5 --(OCHR.sup.3 --CHR.sup.3).sub.v OR.sup.4

R.sup.1 -- O(CHR.sup.3 --CHR.sup.3 O).sub.u --CO--R.sup.2 !.sub.x, and/or

di- or triallylamine and/or bisacrylamide

with

R¹ : multivalent C2-10-alkyl,

R² : linear or branched C2-10-alkenyl,

R³ : H, CH₃, C₂ H₅,

R⁴ : H, linear or branched C1-10-alkyl,

R⁶ : CO, CH₂

R⁸ : H, CH₃

x: 2-6

u: 0-15

V: 1-45

z: 3-20

As compared with the state of the art, the polymers according to the present invention have an improved combination of the properties retention, liquid absorption under pressure at 63 g/cm² and soluble contents, moreover, they have an Increased permeability of the gel layer for watery liquids, a high suction rate, and a high swelling pressure. The polymers are used as absorbents for water and watery liquids in constructions for the absorption of body fluids, In electricity or light-conducting cables, and in plant raising.

Claims

1. A cross-linked polymer useful for absorbing watery liquids, built-up of partially neutralized monomers having monoethylenically unsaturated acid groups and optionally further monomers copolymerizable therewith, wherein the polymer is manufactured with use of a combination of components

View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)

2. A polymer as claimed in claim 1, which has a retention value >

30 g/g, an absorption value under pressure of 49 g/cm² of >

20 g/g, an absorption value under pressure of 63 g/cm² after milling of >

18 g/g, a rate of absorption liquid of <

40 s, a swelling pressure of >

800 g, and a soluble contents of <

10%.

3. A polymer as claimed in claim 1, wherein the polymer contains 0.05-0.6% by weight of component I, 0.5-5% by weight of component II, and 0.05 to 0.6% by weight of component III, relative to the total weight of monomers in the polymer.

4. A polymer as claimed in claim 1, wherein the polymer contains 0.1-0.4% by weight of component I, 1.0-3.5% by weight of component II, and 0.05-0.3% by weight of component III, relative to the total weight of monomers in the polymer.

5. A polymer as claimed in claim 1, wherein component I comprises an allyl polyethylene glycol-(meth) acrylic acid esters, component II comprises a methyl polyethylene glycol-(meth)acrylates, and component III is selected from the group consisting of trimethylolpropane oxethylate-(meth)acrylic acid esters, glycerol oxethylate-(meth)acrylic acid esters, pentaerythritol oxethylate-(meth)acrylic acid esters, polyethylene glycol-α

,ω

-di(meth)acrylic acid esters and di- or triallylamine, N,N-methylenebisacrylamide, and bisacrylamido acetic acid.

6. A polymer as claimed in claim 1, wherein the monomers having monoethylenically unsaturated acid groups are selected from the group consisting of acrylic acid, methacrylic acid, vinyl acetic acid, vinyl sulfonic acid, methallyl sulfonic acid, and 2-acrylamido-2-methyl propane sulfonic acid.

7. A polymer as claimed in claim 1, that comprises 0 to 40% by weight of further comonomers selected from the group consisting of (meth)acrylamide, (meth)acrylonitrile, vinyl pyrrolidone, hydroxy ethyl acrylate, and vinyl acetamide.

8. A polymer as claimed in claim 1, which comprises up to 30% by weight of water-soluble polymers as a graft basis.

9. A polymer as claimed in claim 1, which comprises a polysaccharide or polyvinyl alcohol as a graft basis.

10. A polymer as claimed in claim 1, which has been crosslinked on the surface with a re-cross-linking agent and wherein this re-cross-linkage has optionally been repeated.

11. A polymer according to claim 10, wherein the re-cross-linking agent is selected from the group consisting of polyols, polyepoxides, polyamines, and alkylene carbonates.

12. A polymer as claimed in claim 10, which has a retention of at least 30 g/g, a liquid up-take pressure at 49 g/cm² of at least 20 g/g, and a liquid up-take under pressure at 63 g/cm² after SDOV of at least 18 g/g, and a content of soluble components after 1 hour at a maximum of 6.5% and after 18 hours at a maximum of 10%, and an absorption against a pressure of 50 g/cm² with a suction surface reduced by 34% (AAP-A₃₄) of at least 15 g/g, and at least 50% of the initial value of the absorption against pressure without surface reduction.

13. A polymer as claimed in claim 10, which has a liquid take-up under pressure of 63 g/cm² after SDOV of at least 20 g/g, and an AAP-A₃₄ of at least 10 g/g.

14. A polymer as claimed in claim 10, which has a swelling pressure after 20 minutes of at least 600 g.

15. A polymer as claimed in claim 10, which has a content of soluble components after 16 hours at a maximum of 8%.

16. A polymer as claimed in claim 10, which has a liquid take-up under pressure of 63 g/cm² of greater than 23 g/g.

17. A polymer according to claim 10, which has a rate of liquid take-up of less than 40 seconds.

18. A process of making a polymer according to claim 1, which comprises polymerizing to a hydrogel (i) a watery solution of the monomers having monoethylenically unsaturated acid groups and (ii) components I, II, and III, in the presence of a radical forming agents, by solution or suspension polymerization, and crushing, drying, grounding, and sieving the hydrogel.

19. A process as claimed in claim 18, further comprising treating the polymer with a surface cross-linking agent, and wherein surface cross-linkage is carried out at an elevated temperature.

20. A process as claimed in claim 19, wherein the polymer is treated with the surface cross-linking agent several times and the surface cross-linkage is carried out several times.

21. A method of using a polymer as claimed in claim 1, comprising absorbing water or a watery liquid with the polymer.

22. A method of using a polymer as claimed in claim 1, comprising absorbing body fluids with the polymer.

23. A polymer as claimed in claim 1, comprising 55-99%by weight of the monomers having monoethylinically unsaturated acid groups, that are optionally neutralized, based on the total weight of monomers.