Sulfoalkyl group-containing hydrophobic modified cellulose ethers are useful as protective colloids in emulsion polymerization, less protective colloid is required, and the dispersions obtained have improved quality

摘要

Water soluble ionic cellulose ethers from the hydroxyalkylcellulose group, substituted by 0.001-1.0, preferably 0.001-0.2 alkyl groups, per anhydroglucose unit and which carry 0.01-0.1 sulfoalkyl groups per anhydroglucose unit are new, and are outstandingly useful as protective colloids in emulsion polymerization. New water soluble ionic cellulose ethers from the hydroxyalkylcellulose group, substituted by 0.001-1.0, preferably 0.001-0.2, alkyl groups per anhydroglucose unit carry 0.01-0.1 sulfoalkyl groups per anhydroglucose unit. The cellulose ethers have the formula (I): where: C6H7O2 = an anhydroglucose unit, m = 50-3000, preferably 100-1000, and R1-R3 = a polyalkylene oxide chain of formula (II): where X = H, CnH(2n+1)O, CH2-CH2-SO3Y, CH2CHOH-CH2SO3Y, where: n = 4-20; Y = H, Na, K, p,q, and r can have the values = 0-4 in R1-R3; The sum of (p+q+r) added to R1-R3 per anhydroglucoise unit exceeds 1.3 and is less than 4.5, and is preferably 1.5-3.0, the series of oxyalkyl units in the polyalkylene oxide chain is random, the mean number of hydrophobically modified groups per anhydroglucose unit (DS HM) is 0.001-0.2, preferably 0.01-0.04, the mean number of sulfoalkyl groups per anhydroglucose unit is 0.01-0.1, preferably 0.01-0.01. Independent claims are included for: (1) preparation of cellulose ether by etherification of cellulose with an alkylene oxide etherification agent, and etherification with an alkyl halogenide or an alkylglycidyl ether and a sulfonate under base catalysis conditions; (2) an aqueous polymer dispersion obtained by radical initiated polymerization of ethylenically unsaturated monomers in aqueous emulsion in the presence of 0.2-5.0 wt.%, on the total wt.% monomers of water soluble ionic cellulose ethers selected from hydroxyalkyl cellulose, substituted with 0.001-1.0 alkyl groups per anhydroglucose unit and 0.01-0.4 sulfoalkyl groups per anhydroglucose unit.