Polymerized hydrogel comprising low amounts of residual monomers and by-products
First Claim
1. A process for making a hydrogel comprising from about 10 to 90 wt % water, from about 10 to 60 wt % of cross-linked hydrophilic polymer made from at least one starting monomer type, and from about 10 to 80 wt % of at least one polyol, said process comprising the steps of:
- 1) polymerizing said starting monomer(s) from within a reaction medium comprising from about 10 to 90 wt % of water, from about 10 to 60 wt % of said starting monomer(s) and from about 10 to 80 wt % of said polyol(s), to thereby form a hydrogel;
and thereafter 2) chemically treating said hydrogel with a compound which reacts with residual starting monomer(s), impurity(s) and/or any by-products produced by said polymerization reaction, to thereby reduce the concentration of said residual starting monomer(s), impurity(s) and/or by-products within said hydrogel.
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Abstract
The present invention relates to a process for making polymerized hydrogel, in particular adhesives, which are characterized by very low amount of residual starting monomer(s), impurity(s) and/or by-products which could be formed during polymerization, such as acrylamide, acrylonitrile or acrolein.
After a first polymerization step, which is conducted from a reaction medium comprising starting monomer(s) and at least one polyol, the resulting hydrogel is then post-treated with a compound which chemically reacts with said residual monomer(s), impurity(s) and/or with said by-products the said polymerization could produce, to thereby reduce said residual starting monomer(s), impurity(s) and/or said by-products within said hydrogel.
The present invention also relates to polymerized hydrogels, in particular adhesives, comprising 10-90 wt % water, 10-60 wt % cross-linked hydrophilic polymer made from starting monomer(s) comprising acrylic acid, and 10-80 wt % of at least one polyol, such hydrogel being prepared by polymerizing said starting monomer(s) in the presence of said water and said polyol(s), wherein such hydrogels contain less than 500 ppb, preferably less than 100 ppb, more preferably less than 50 ppb and most preferably less than 20 ppb of α,β-unsaturated carbonyl by-product(s) derived from said polyol(s) during polymerization, and wherein the level of residual starting monomer(s) is below 200 ppm, preferably below 100 ppm, more preferably below 50 ppm, even more preferably below 20 ppm, and most preferably below 10 ppm.
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Citations
36 Claims
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1. A process for making a hydrogel comprising from about 10 to 90 wt % water, from about 10 to 60 wt % of cross-linked hydrophilic polymer made from at least one starting monomer type, and from about 10 to 80 wt % of at least one polyol, said process comprising the steps of:
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1) polymerizing said starting monomer(s) from within a reaction medium comprising from about 10 to 90 wt % of water, from about 10 to 60 wt % of said starting monomer(s) and from about 10 to 80 wt % of said polyol(s), to thereby form a hydrogel;
and thereafter2) chemically treating said hydrogel with a compound which reacts with residual starting monomer(s), impurity(s) and/or any by-products produced by said polymerization reaction, to thereby reduce the concentration of said residual starting monomer(s), impurity(s) and/or by-products within said hydrogel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 30)
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23. A hydrogel comprising from about 10 to 90 wt % water, from about 10 to 60 wt % of cross-linked hydrophilic polymer made from starting monomer(s), and from about 10 to 80 wt % of a at least one polyol, said hydrogel being prepared by polymerizing said starting monomer(s) in the presence of said water and polyol(s), wherein said hydrogel comprises less than about 100 ppb of α
- ,β
-unsaturated carbonyl by-product(s) derived from said polyol(s) during polymerization. - View Dependent Claims (24, 25, 26, 27, 28, 29)
- ,β
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31. A hydrogel comprising from about 10 to 90 wt % of water, from about 10 to 60 wt % of cross-linked hydrophilic polymer made from starting monomer(s), and from about 10 to 80 wt % of polyol(s), said hydrogel being prepared by polymerizing said starting monomer(s) in the presence of said water and said polyol(s) and thereafter, treating the formed product with a nucleophilic compound which reacts with α
- ,β
-unsaturated carbonyl by-product(s) derived from said polyol(s) during polymerization, wherein said hydrogel comprises more than about 20 ppb of nucleophilic addition product(s) of said α
,β
-unsaturated carbonyl by-product(s) with said nucloephilic compound. - View Dependent Claims (32, 33, 34, 35, 36)
- ,β
Specification