Coating composition containing as thickeners polygalactomannans modified with hydrophilic and hydrophobic groups

In a coating composition comprised of an aqueous dispersion of a film-forming synthetic resin, pigments, and fillers, the improvement which comprises using as a thickening and rheology control agent about 0.1 to about 2 weight percent of the composition of a poly(alkl ether) of a polygalactomannan having two different alkyl ether substituents wherein one alkyl ether substituent is a hydrophilic group selected from the group consisting of R and HOR.sup.1, wherein R is an alkyl group containing one to four carbon atoms, wherein R.sup.1 is an alkylene group containing two to four carbon atoms and wherein the OH group is on the carbon atom beta to the ether group, wherein the other alkyl substituent is a hydrophobic group selected from the group consisting of R.sup.2, HOR.sup.3, and ##STR3## wherein R.sup.2 is an alkyl group containing about eight to about twenty-eight carbon atoms, wherein R.sup.3 is an alkylene group which contains about 8 to about 28 carbon atoms having the OH group on the carbon atom beta to the ether group and wherein R.sup.4 is an alkyl group containing about 5 to about 25 carbon atoms, wherein the substituent, R or HOR.sup.1, is present in a M.S. of about 0.2 to about 2, wherein the substituent, R.sup.2, HOR.sup.3, or ##STR4## is present in a M.S. of about 0.001 to about 0.2 and wherein the viscosity of the polygalactomannan prior to derivatization with the hydrophobic group has a viscosity as measured as a 2 weight percent solution in water at 25.degree. C. of about 100 to about 2000 cps.