Patent EP-1795265-A2 (EP)
Title: Use of weakly anionic copolymers as grinding aid agents of an aqueous suspension of mineral materials,  aqueous suspensions obtained and uses thereof.
Inventor: SUAU JEAN-MARC
IPC: C09D7/45
Filed: 2001-06-12
Abstract: Water-soluble weakly anionic copolymer comprises ethylenically unsaturated anionic monomers with mono-carboxylic, di-carboxylic, sulfonic, phosphoric or phosphonic groups, non-ionic ethylenically unsaturated monomer, (meth)acrylamide or (meth)acrylate type monomer(s) and doubly ethylenically unsaturated monomers. Water-soluble weakly anionic copolymer, used as dispersing/grinding agent for aqueous suspensions of pigments and/or mineral fillers, comprises: (a) at least one ethylenically unsaturated anionic monomer A with mono-carboxylic group, selected from (meth)acrylic acids or diacid hemi-esters such as 1-4C monoesters of maleic or itaconic acids, or their mixtures; (b) optionally at least one ethylenically unsaturated anionic monomer B with dicarboxylic, sulfonic, phosphoric or phosphonic group, or their mixtures, selected from crotonic, isocrotonic, cinnamic, itaconic, maleic or citraconic acids, or anhydrides such as maleic anhydride, acrylamido-methyl- propane-sulfonic acid, sodium meth-allyl sulfonate, vinyl sulfonic and styrene-sulfonic acids, or vinyl phosphoric acid, ethylene or propylene glycol (meth)acrylate phosphate and their ethoxylates, or from vinyl phosphonic acid, or their mixtures; and (c) at least one non-ionic ethylenically unsaturated monomer of formula (I); (d) optionally a monomer D of type of (meth)acrylamide or their derivatives and mixtures, or one or more water non-soluble monomers D1 such as alkyl (meth)acrylate, vinyl acetate, vinylpyrrolidone, styrene, alpha-methyl styrene and their derivatives; and (e) optionally at least one monomer E with at least two ethylenic unsaturations, selected from ethylene glycol dimethacrylate, trimethylol propane triacrylate, allyl acrylate or maleates, methylene- bis-(meth)acrylamide, tetra-allyloxy ethane, triallyl cyanurates and allylic ethers obtained from polyols such as pentaerythritol, sorbitol, sucrose or others, with components (a), (b), (c), (d) and (e) amounting to total of 100%. The copolymer has specific viscosity up to 10 and especially up to 2. [Image] R 1H, methyl or ethyl radical; R 2H, methyl or ethyl radical; R : polymerizable unsaturated radical, selected from (meth)acrylic, maleic, itaconic, crotonic and vinylphthalic esters, unsaturated urethanes such as (meth)acryl urethane, alpha-alpha dimethyl- isopropenyl-benzyl urethane and allyl urethane, allyl or vinyl esters or ethylenically unsaturated amides; R' : 1-5C hydrocarbon radical; m and p : number of alkylene oxide groups up to 150; n : number of ethylene oxide groups up to 150; q : at least 1, with (m+n+p)q equal 5-150 Independent claims are also included for: (1) dispersing and/or grinding agent for pigments and/or mineral fillers in aqueous suspensions, consisting of copolymer as claimed, of composition as described below; (2) aqueous suspension of fillers and/or pigments, containing 0.05-5 wt.% (preferably 0.3-1.0 wt.%) of dispersing agent as claimed; (3) use of aqueous suspension of fillers and/or pigments in making and/or layering of paper; (4) paper sheets containing aqueous suspension of fillers and/or pigments as claimed; (5) use of aqueous suspension of fillers and/or pigments as claimed in drilling muds for oil prospecting or extraction, especially saturated saline muds and marine muds; (6) drilling mud containing aqueous suspension of fillers and/or pigments as claimed; (7) use of dispersing and/or grinding agent for pigments and/or mineral fillers in aqueous suspensions as claimed employed in paint industry; and (8) use of dispersing and/or grinding agent for pigments and/or mineral fillers in aqueous suspensions as claimed employed in field of plastic materials, especially thermoplastic or thermosetting resins.