Cytec Surface Specialties

Surf Chip, Inc.

Cytec Surface Specialties, S.a.

Jong-Shing Guo

Augustin T Chen

Leo Ternorutsky

Sharon D Trembley

Tibor Pernecker

Augustin Chen

Removable, water-whitening resistant pressure sensitive adhesive (PSA) comprising a crosslinked aqueous emulsion polymer comprising (a) at least one hydrophobic monomer; (b) at least about 2 wt. % of at least one hydrophilic monomer; and (c) at least about 5 wt. % of at least one partially hydrophilic monomer; wherein the crosslinked aqueous emulsion polymer is crosslinked with an effective amount of at least one polyfunctional aziridine crosslinker, and the wt. % of monomers (a), (b), and (c) are based on the total weight of monomers (a), (b), and (c).

Removable, water-whitening resistant pressure sensitive adhesives

Pressure sensitive adhesive compositions having enhanced resistance to water-whitening comprising an aqueous emulsion polymer are disclosed. The polymer comprises the polymerization reaction product of a polymerizable aqueous emulsion comprising: (i) at least one hydrophobic alkyl acrylate or alkyl methacrylate ester of an alcohol, (ii) at least about 1 wt. % of at least one hydrophilic monomer, (iii) at least about 5 wt. % of at least one partially hydrophilic alkyl acrylate or alkyl methacrylate ester of an alcohol, and (iv) a water-soluble or water-dispersible polymerizable surfactant selected from compounds having a terminal allyl amine moiety, substituted phenyl compounds having at least one alkenyl substituent, polyoxyalkylene-1-(allyloxymethyl) alkyl ether sulfate salts, or mixtures thereof, and the average particle size of the polymer is less than or equal to 200 nm. Also disclosed are processes for preparing same.

Process for improving water-whitening resistance of pressure sensitive adhesives

Removable pressure sensitive adhesive compositions having enhanced resistance to water-whitening comprising a crosslinked aqueous emulsion polymer are disclosed. The crosslinked aqueous emulsion polymer comprises (a) at least one hydrophobic monomer; (b) greater than 1 wt. % of at least one hydrophilic monomer; (c) greater than 3 wt. % of at least one mono-olefinically unsaturated monomer having an aldehyde or ketone group; (d) optionally at least one partially hydrophilic monomer; and (e) an effective amount of at least one water-soluble or water-dispersible polymerizable surfactant; wherein the crosslinked aqueous emulsion polymer is crosslinked with an effective amount of at least one polyhydrazide crosslinker, the wt. % of monomers (a), (b), (c) and (d) are based on the total weight of monomers (a), (b), (c) and (d), and the mean particle size of the crosslinked aqueous emulsion polymer is less than about 400 nm.

In forming pressure sensitive adhesive microspheres by copolymerizing a non-ionic monomer of an alkyl acrylate or alkyl methacrylate ester of a non-tertiary alcohol and an acid monomer copolymerizable with said non-ionic monomer, an electrolyte is present during the polymerization to promote formation of solid rather than hollow microspheres.

Process for forming solid pressure sensitive adhesive polymer microspheres

Pressure sensitive adhesive compositions having enhanced resistance to water-whitening comprising an aqueous emulsion polymer are disclosed. The polymer comprises the polymerization reaction product of a polymerizable aqueous emulsion comprising: (i) a hydrophobic monomer mixture of at least one alkyl acrylate or alkyl methacrylate ester of an alcohol wherein the alkyl portion of the alcohol is linear or branched and contains at least 4 carbon atoms, and at least one styrenic monomer, wherein the styrenic monomer is up to about 30 wt. % of the total hydrophobic monomer mixture, (ii) at least about 1 wt. % of at least one hydrophilic monomer, (iii) at least about 5 wt. % of at least one partially hydrophilic monomer selected from alkyl acrylate or alkyl methacrylate esters of an alcohol wherein the alkyl portion of the alcohol has 1 to 2 carbon atoms, N-vinyl-2-pyrrolidone, or mixtures thererof, and (iv) a water-soluble or water-dispersible polymerizable surfactant selected from compounds having a terminal allyl amine moiety, polyoxyalkylene-1-(allyloxymethyl) alkyl ether sulfate salts, or mixtures thereof, and the average particle size of the polymer is less than or equal to 200 nm. Also disclosed are processes for preparing same.

In forming pressure sensitive adhesive microspheres by copolymerizing a non-ionic monomer of an alkyl acrylate or alkyl methacrylate ester of a non-tertiary alcohol and an ionic monomer copolymerizable with said non-ionic monomer, non-free radically polymerizable acid is present during the polymerization to promote formation of solid rather than hollow microspheres and to reduce residual unconverted ionic monomer. These microspheres exhibit reduced adhesive transfer in downstream use as a repositionable pressure sensitive adhesive. A water soluble initiator is optionally added to the polymerization mixture after achieving about 90% conversion of the non-ionic monomer to further reduce residual unconverted ionic monomer.

Growing community of inventors

Longmeadow, MA, United States of America

Jong-Shing Guo