Patent ZA-200503284-B (ZA)
Title: Aqueous suspensions of ground mineral materials, with low ion load and their uses
Inventor: GANE PATRICK A C
IPC: C08F290/06
Filed: 2003-11-06
Abstract: Aqueous suspensions of purified minerals (A) contain a milling aid comprising a copolymer (B), having intrinsic viscosity 100 ml/g or less, obtained from: (a) ethylenically unsaturated anionic monomer(s) with an acid function; (b) non-ionic ethylenic monomer(s) (I) on which at least one alkoxy- or hydroxy-polyalkylene glycol function is grafted; (c) organosilicon or organofluorine monomer(s); and (d) optionally (meth)acrylamide type, water-insoluble, cationic or quaternary ammonium and/or crosslinking monomer(s).  Aqueous suspensions of purified minerals (A) contain a milling aid comprising a copolymer (B), having an intrinsic viscosity of 100 ml/g or less, obtained from: (1)  at least one ethylenically unsaturated anionic monomer with a monocarboxylic acid function (e.g. (meth)acrylic acid or a diacid monoester such as a mono-(1-4C) ester of maleic or itaconic acid), dicarboxylic acid function (e.g. crotonic, isocrotonic, cinnamic, itaconic or maleic acid, or a corresponding anhydride such as maleic anhydride), a sulfonic acid function (e.g. acrylamido-methyl-propane-sulfonic acid, sodium methallylsulfonate, vinyl-sulfonic acid or styrene-sulfonic acid), a phosphoric acid function (e.g. vinylphosphoric acid, ethylene glycol methacrylate phosphate, propylene glycol acrylate phosphate or their ethoxylates) or a phosphonic acid function (e.g. vinylphosphonic acid);  (2) at least one non-ionic unsaturated monomer of formula (I);  (3) at least one organosilicon or organofluorine monomer, preferably a silicon-containing monomer of formula (IIa), R-A-Si(OB)3 (IIb) or (IIc);  (4) optionally one or more of (a) monomers of the (meth)acrylamide (or derivative) type, (e.g. N-(3-(dimethylamino)-propyl)-(meth)acrylamide), (b) water-insoluble monomers such as alkyl (meth)acrylates, unsaturated esters (e.g. N-(2-dimethylamino)-ethyl)-(meth)acrylate) or vinyl compounds (e.g. vinyl acetate, vinyl pyrrolidone, styrene, alpha-methyl-styrene or their derivatives) or (c) cationic or quaternary ammonium monomers such as (2-((meth)acryloyloxy)-ethyl)-trimethylammonium, (3-((meth)acrylamido)-propyl)-trimethylammonium or dimethyl diallylammonium chloride or sulfate; and  (5) optionally one or more crosslinking monomer selected from ethylene glycol dimethacrylate, trimethylol propane triacrylate, allyl acrylate, allyl maleate, methylene-bis-(meth)acrylamide, tetraallyloxy-ethane or allyl ethers of polyols (e.g. pentaerythritol, sorbitol or sucrose). (Structures (I), page 85, (IIa), page 87, and (IIc), page 88)  m, p, n,  =  up to 150;  q  =  integer such that (m + n + p)/q = 5-150 (preferably 15-120);  R1, R2  =  H, Me or Et;  R  =  radical containing a polymerizable unsaturated selected from vinyl, (meth)acrylic, maleic, itaconic, crotonic or vinylphthalic acid ester, unsaturated urethane (e.g. (meth)acrylurethane, alpha,alpha'-dimethyl-isopropenyl-benzyl urethane or allyl urethane), optionally substituted allyl or vinyl ether or ethylenically unsaturated amide or imide;  R'  =  H or 1-40C hydrocarbyl (preferably 1-12C (especially 1-4C) hydrocarbyl);  m1 - m4, p1 - p4, n1 - n4  =  up to 150;  q1 - q4  =  integers such that (m1 + n1 + p1)/q1, (m2 + n2 + p2)/q2, (m3 + n3 + p3)/q3 and (m4 + n4 + p4)/q4 = 0-150;  r, r'  =  1-200;  R3, R13  =  as for R;  R4, R5, R10, R11, R14, R15, R20, R21  =  H, Me or Et;  R6 - R9, R16 - R19  =  alkyl, aryl, aralkyl or alkaryl of 1-20C;  R12  =  1-40C hydrocarbyl;  A, B, D, E  =  direct bond or 1-4C, hydrocarbyl, provided that B is not a direct bond in (IIb). Independent claims are included for: (a) agents for aiding the milling of (A) in aqueous suspension, comprising the copolymers (B); and  (b) a milling process for obtaining suspensions of very fine particles of (A), including the addition of 0.05-10 wt. % (as solids based on (A)) of (B) before and/or during the miling stage, optionally in combination with other dispersants or milling aids.