(Meth)acrylic comb polymer containing a (meth)acrylic ester as a dispersing and anti-defoaming agent in an aqueous suspension of calcium sulfate hemihydrate
AssigneeCoatex
InventorsJean-Marc Suau, Yves Kensicher
Life of this patent
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Abstract
This invention relates to the use, in a foamy aqueous suspension of calcium sulfate hemihydrate, as an agent having the dual function of being a dispersing agent and an anti-defoaming agent, of a comb polymer made up of (meth)acrylic acid, a monomer which is an alcoxy- or hydroxy-polyalkylene glycol, and an ester of (meth)acrylic acid. It also relates to the aqueous suspensions thereby formed, and the plasterboard manufactured from 2 sheets of paper containing a body resulting from the drying of said suspensions.
Claims17
A foamy aqueous suspension of calcium sulfate hemihydrate, comprising water, calcium sulfate hemihydrate, and a comb polymer comprising, expressed as a percentage by weight of the total weight, monomers a), b) and c):
- a) from 5% to 30% of at least one monomer which is (meth)acrylic acid,
- b) from 1% to 20% of at least one monomer which is an ester of (meth)acrylic acid, and
- c) from 70% to 90% of at least one monomer which is an alcoxy- or hydroxy-polyalkylene glycol,
- the sum of percentages a), b) and c) being equal to at least 50% by weight of the total weight of the comb polymer.
A comb polymer wherein said comb polymer comprises, expressed as a percentage by weight of the total weight, monomers a), b) and c):
- a) from 5% to 30% of at least one monomer which is (meth)acrylic acid,
- b) from 1% to 20% of at least one monomer which is an ester of (meth)acrylic acid, and
- c) from 70% to 90% of at least one monomer which is an alcoxy- or hydroxy-polyalkylene glycol,
- the sum of percentages a), b) and c) being equal to at least 50% by weight of the total weight of the comb polymer.
A comb polymer consisting of, expressed as a percentage by weight of the total weight, monomers a), b) and c) as follows:
- a) from 5% to 30% of methacrylic acid
- b) from 1% to 20% of one of ethyl acrylate, butyl acrylate, and methyl methacrylate
- c) from 70% to 90% a monomer of formula (I):
- R-(A-O)m—(B—O)n—R′ (I)
- m and n are integers less than 150, at least one of which is nonzero,
- A and B designate alkyl groups which are different from one another, and having 2 to 4 carbon atoms,
- R designates a polymerizable unsaturated function,
- R′ represents hydrogen or an alkyl group having 1 to 4 carbon atoms,
- the sum of percentages a), b) and c) being equal to 100% by weight of the total weight of the comb polymer.
Dependencies are inferred from the claim text.