Aqueous super absorbent polymer and methods of use
View Patent ↗The present invention relates to a crosslinked aqueous solution polymer composition consisting of about 15 wt-% to about 50 wt-% of at least one water soluble monomer, preferably an alpha, beta-ethylenically unsaturated carboxylic acid monomer and a crosslinking agent. The polymer solution is sufficiently low enough in viscosity such that it can be applied in aqueous form, yet after crosslinking possesses a fast rate of acquisition and is high absorption capacity. The invention also relates to new methods of enhancing the absorbency of various articles, increasing the humectancy and/or absorbency of a fiber or fibrous matrix, improving the water retention of soil and other agricultural methods, and increasing the open time of cement by incorporating or applying an aqueous superabsorbent polymer composition.
1. A method of increasing the humectancy of a fiber, said method comprising:
a) applying an aqueous polymer composition on a fiber, said aqueous polymer composition comprising
i) a polymer derived from monomers consisting of water soluble α-β-ethylenically unsaturated carboxylic acid monomers, said polymer having been from about 75% to 95% neutralized with a base selected from the group consisting of alkali metal hydroxide, alkaline earth metal hydroxide, and combinations thereof, said polymer having been further neutralized with a volatile base to a pH of at least 7; and
ii) a crosslinking agent,
said composition having a viscosity of from about 50 cP to about 20,000 cP at 25° C.; and
b) drying said composition.
2. The method of claim 1 , wherein said fiber comprises cellulose.
3. A method of making a fibrous web, said method comprising
forming a layer of fibers prepared according to the method of claim 1 ; and
contacting said layer of fibers with a binder to bond said fibers together to form a web.
4. The method of claim 3 , wherein said forming comprises air-laying, wet laying, garneting, carding or a combination thereof.
5. The method of claim 3 , wherein said fibers comprise cellulose.
6. The method of claim 5 , wherein said fibrous web comprises a paper product.
7. The method of claim 5 , wherein said fibrous web comprises paper toweling.
8. The method of claim 1 , wherein said aqueous polymer composition further comprises at least one of a water-borne emulsion polymer and a water-based adhesive.
9. The method of claim 8 , wherein said aqueous polymer composition further comprises said water-based adhesive and said water-based adhesive is selected from the group consisting of acrylic, vinyl acrylic, styrene acrylic, styrene butadiene rubber, vinyl acetate-versatic acid esters, vinyl acetate-ethylene and combinations thereof.
10. A method of making an absorbent fibrous web, said method comprising:
a) spraying an aqueous polymer composition on a web comprising fibers, said aqueous polymer composition having been prepared by a method comprising
i) solution polymerizing monomers comprising water soluble α,β-ethylenically unsaturated carboxylic acid monomers to form a solution polymer,
ii) neutralizing the carboxylic acid groups of the solution polymer with a base selected from the group consisting of alkali metal hydroxide, alkaline earth metal hydroxide, and combinations thereof to a pH of at least 7; and
iii) adding a crosslinking agent to said solution polymer, said crosslinking agent comprising potassium zirconyl carbonate,
said composition comprising from about 5% by weight to about 65% by weight solids and having a viscosity of from about 100 cP to about 2500 cP at 25° C.; and
b) drying said composition.