Method for Producing Water-Absorbing Polymers
First Claim
1. A process for preparing a water absorbing polymer by polymerization of a monomer solution comprisinga) acrylic acid, which may be partially or completely neutralized,b) at least one crosslinker,c) allyl acrylate and/or allyl alcohol,d) optionally one or more ethylenically and/or allylically unsaturated monomer copolymerizable with the monomer identified under a), ande) one or more water soluble polymer,wherein the solution comprises not more than 0.002% by weight of allyl acrylate and/or allyl alcohol, based on acrylic acid.
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Abstract
The invention relates to processes for preparing water absorbing polymers by polymerization of a monomer solution comprising allyl acrylate and/or allyl alcohol, the solution comprising not more than 0.002% by weight of allyl acrylate and/or allyl alcohol, based on acrylic acid, to aqueous monomer solutions for producing water absorbing polymers, to water absorbing polymers, to processes for producing hygiene articles and also to hygiene articles.
22 Citations
14 Claims
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1. A process for preparing a water absorbing polymer by polymerization of a monomer solution comprising
a) acrylic acid, which may be partially or completely neutralized, b) at least one crosslinker, c) allyl acrylate and/or allyl alcohol, d) optionally one or more ethylenically and/or allylically unsaturated monomer copolymerizable with the monomer identified under a), and e) one or more water soluble polymer, wherein the solution comprises not more than 0.002% by weight of allyl acrylate and/or allyl alcohol, based on acrylic acid.
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8. An aqueous monomer solution to prepare a water absorbing polymer which comprises
a) acrylic acid, which may be partially or completely neutralized, b) at least one crosslinker, c) allyl acrylate and/or allyl alcohol, d) optionally one or more ethylenically and/or allylically unsaturated monomer copolymerizable with the monomer identified under a), and e) optionally one or more water soluble polymer, wherein the solution comprises not more than 0.002% by weight of allyl acrylate and/or allyl alcohol, based on acrylic acid.
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10. A water absorbing polymer comprising
i) interpolymerized acrylic acid, which may be partially or completely neutralized, ii) at least one interpolymerized crosslinker, iii) interpolymerized allyl acrylate and/or allyl alcohol, iv) optionally one or more interpolymerized ethylenically and/or allylically unsaturated monomer copolymerizable with the monomer identified under i), and v) optionally one or more water soluble polymer onto which the monomer identified under i) is at least partially grafted, wherein the polymer comprises not more than 0.002% by weight of interpolymerized allyl acrylate and/or interpolymerized allyl alcohol, based on interpolymerized acrylic acid.
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11. (canceled)
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14. The process according to 5 wherein the acrylic acid comprises not less than 0.005% by weight of allyl acrylate and/or allyl alcohol before crystallization.
Specification