초록 ▼

This invention relates to a thixotropic thickening agent and to a process for preparing the same. Such thixotropic thickening agents are particularly useful for thickening water reducible coatings. The thixotropic thickening agents of this invention are copolymers which are comprised of repeat units

This invention relates to a thixotropic thickening agent and to a process for preparing the same. Such thixotropic thickening agents are particularly useful for thickening water reducible coatings. The thixotropic thickening agents of this invention are copolymers which are comprised of repeat units which are derived from methacrylic acid monomer, ethylacrylate monomer, and a water soluble crosslinking agent. The water soluble crosslinking agents which can be used include ethylene glycol dimethacrylate and alkylene bisacrylamides, such as N,N′-methylene bisacrylamide. A neutralized two weight percent aqueous solution of the thixotropic thickening agents of this invention will have a Brookfield RVT viscosity as measured at 50 rpm using a number 3 spindle within the range of 50 to 2000 centipoise (cps).

대표청구항 ▼

A copolymer which can be utilized as a thixotropic thickening agent for use in aqueous coating systems which consists of repeat units which are derived from methacrylic acid monomer, ethylacrylate monomer, and a water soluble crosslinking agent selected from the group consisting of alkylene bisacryl

A copolymer which can be utilized as a thixotropic thickening agent for use in aqueous coating systems which consists of repeat units which are derived from methacrylic acid monomer, ethylacrylate monomer, and a water soluble crosslinking agent selected from the group consisting of alkylene bisacrylamides and ethylene glycol dimethacrylate; wherein from 25 to 55 weight percent of the repeat units in said copolymer are derived from ethylacrylate, wherein from 45 to 75 weight percent of the repeat units in said copolymer are derived from methacrylic acid wherein from 0.05 to 0.75 weight percent of the repeat units in said copolymer are derived from said water soluble crosslinking agent, and wherein the Brookfield RVT viscosity of a 2 weight percent solution of said copolymer at a pH within the range of 7 to 8 in water as measured at 50 rpm using a number 3 spindle is within the range of 50 to 2000 mPaㆍs. An aqueous coating composition which is comprised of (a) a water reducible resin which is comprised of, based on 100 weight percent of monomeric units within the water reducible resin: (1) from about 50 to about 90 percent of at least one monomer selected from the group consisting of styrene, a2) from about 10 to about 40 of at least one alkyl acrylate monomer wherein the alkyl moiety contains from 3 to 5 carbon atoms, and (3) from about 1 to about 10 percent of at least one unsaturated carbonyl compound selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, itaconic acid, maleic acid and maleic anhydride; (b) a thixotropic thickening agent which is comprised of repeat units which are derived from methacrylic acid monomer, ethylacrylate monomer, and a water soluble crosslinking agent, wherein from 25 to 55 weight percent of the repeat units in said copolymer are derived from ethylacrylate monomer, wherein from 45 to 75 weight percent of the repeat units in said copolymer are derived from methacrylic acid monomer, and wherein from 0.05 to 0.75 weight percent of the repeat units in said copolymer are derived from said water soluble crosslinking agent; (c) a pigment; (d) a plasticizer; and (e) water.