US5212273A — Crosslinked polymeric microparticles; their metho…

Claim 1

Independent Claim 165 words

Crosslinked polymeric microparticles useful as rheology control agents for coating compositions, said microparticles being prepared by aqueous emulsion polymerization techniques in the presence of a free radical initiator which is soluble in aqueous medium in the absence of polyester emulsifiers from a mixture of polymerizable ethylenically unsaturated monomers containing less than 1 percent by weight of monomers containing polar groups and at least one of said monomers being a polyethylenically unsaturated crosslinking monomer free of oxyethylene groups and present in amounts of 20 to 50 percent by weight based on total weight of said polymerizable ethylenically unsaturated monomers; removing water from the resulting emulsion by azeotropic distillation with an organic diluent in which the crosslinked polymeric microparticles are insoluble and which forms an azeotrope with water to form a dispersion of the crosslinked polymeric microparticles having a particle size within the range of 0.005 to 1 micron and which are crosslinked to an extent of at least 80 percent by weight in the organic diluent.

Claim 2

Dependent Claim 165 words

Crosslinked polymeric microparticles useful as rheology control agents for coating compositions, said microparticles being prepared by aqueous emulsion polymerization techniques in the presence of a free radical initiator which is soluble in aqueous medium in the absence of polyester emulsifiers from a mixture of polymerizable ethylenically unsaturated monomers containing less than 1 percent by weight of monomers containing polar groups and at least one of said monomers being a polyethylenically unsaturated crosslinking monomer free of oxyethylene groups and present in amounts of 20 to 50 percent by weight based on total weight of said polymerizable ethylenically unsaturated monomers; removing water from the resulting emulsion by azeotropic distillation with an organic diluent in which the crosslinked polymeric microparticles are insoluble and which forms an azeotrope with water to form a dispersion of the crosslinked polymeric microparticles having a particle size within the range of 0.005 to 1 micron and which are crosslinked to an extent of at least 80 percent by weight in the organic diluent.

Claim 3

Dependent Claim 30 words

The crosslinked polymeric microparticles of claim 1 in which said microparticles are prepared by aqueous emulsion polymerization techniques in the presence of an ammonium salt of ethoxylated alkyl phenol sulfate.

Claim 4

Dependent Claim 18 words

The crosslinked polymeric microparticles of claim 2 in which the ammonium salt is of ethoxylated nonyl phenol sulfate.

Claim 5

Dependent Claim 40 words

The crosslinked polymeric microparticles of claim 1 in which the ethylenically unsaturated monomers other than said crosslinking monomer are selected from the class consisting of alkyl acrylates, alkyl methacrylates and polymerizable ethylenically unsaturated aromatic monomers and mixtures of said monomers.

Claim 6

Dependent Claim 63 words

The crosslinked polymeric microparticles of claim 4 in which the ethylenically unsaturated monomers are selected from the class consisting of alkyl acrylates having 1 to 6 carbon atoms in the alkyl group; alkyl methacrylates having 1 to 6 carbon atoms in the alkyl group; styrene and alkyl-substituted styrenes having 1 to 4 carbon atoms in the alkyl group and mixtures of said monomers.

Claim 7

Dependent Claim 25 words

The crosslinked polymeric microparticles of claim 1 in which the crosslinking monomer is an ester of a polyhydric alcohol and an ethylenically unsaturated monocarboxylic acid.

Claim 8

Dependent Claim 40 words

The crosslinked polymeric microparticles of claim 6 in which the crosslinking monomer is a polyacrylate or polymethacrylate ester of an alkylene polyol having 2 to 3 hydroxyl groups and in which the alkylene group contains 2 to 8 carbon atoms.

Claim 9

Dependent Claim 185 words

A process for preparing crosslinked polymeric microparticles comprising: (a) polymerizing via aqueous emulsion polymerization techniques in the presence of a free radical initiator which is soluble in the aqueous medium in the absence of polyester emulsifiers a mixture of polymerizable ethylenically unsaturated monomers containing less than 1 percent by weight of monomers containing polar groups and at least one of said monomers being a polyethylenically unsaturated crosslinking monomer free of oxyethylene groups and present in amounts of 20 to 50 percent by weight; the percentages based on total weight of said ethylenically unsaturated monomers to form an aqueous emulsion of said crosslinked polymeric microparticles; (b) inverting said aqueous emulsion into organic diluent in which the crosslinked polymeric microparticles are insoluble and which forms an azeotrope with water; (c) heating the mixture formed in (b) to reflux; and (d) removing water from said mixture by azeotropic distillation to form a dispersion of the crosslinked polymeric microparticles having a particle size within the range of 0.005 to 1 micron and which are crosslinked to an extent of at least 80 percent by weight in the organic diluent.

Claim 10

Dependent Claim 185 words

A process for preparing crosslinked polymeric microparticles comprising: (a) polymerizing via aqueous emulsion polymerization techniques in the presence of a free radical initiator which is soluble in the aqueous medium in the absence of polyester emulsifiers a mixture of polymerizable ethylenically unsaturated monomers containing less than 1 percent by weight of monomers containing polar groups and at least one of said monomers being a polyethylenically unsaturated crosslinking monomer free of oxyethylene groups and present in amounts of 20 to 50 percent by weight; the percentages based on total weight of said ethylenically unsaturated monomers to form an aqueous emulsion of said crosslinked polymeric microparticles; (b) inverting said aqueous emulsion into organic diluent in which the crosslinked polymeric microparticles are insoluble and which forms an azeotrope with water; (c) heating the mixture formed in (b) to reflux; and (d) removing water from said mixture by azeotropic distillation to form a dispersion of the crosslinked polymeric microparticles having a particle size within the range of 0.005 to 1 micron and which are crosslinked to an extent of at least 80 percent by weight in the organic diluent.

Claim 11

Dependent Claim 42 words

The process of claim 8 in which the organic diluent has the structure: ##STR2## wherein R 1 is an alkyl group of from 1 to 6 carbon atoms and R 2 is an alkyl group of from 1 to 13 carbon atoms.

Claim 12

Dependent Claim 11 words

The process claim 9 in which the organic diluent is hexylacetate.

Claim 13

Dependent Claim 25 words

The process of claim 9 in which the mixture is held at reflux for at least 6 hours prior to removing water by azeotropic distillation.

Claim 14

Dependent Claim 41 words

A coating composition comprising a film-forming synthetic resin and an organic solvent for said resin and from 1 to 15 percent by weight based on weight of resin solids in said coating composition of the crosslinked polymeric microparticles of claim 1.

Claim 15

Dependent Claim 11 words

The coating composition of claim 12 which further comprises a pigment.

Claim 16

Dependent Claim 17 words

The coating composition of claim 12 which is a clear coating composition being substantially free of pigment.

Claim 17

Dependent Claim 63 words

A process for applying a composite coating to a substrate which comprises applying to the substrate a colored film-forming composition to form a base coat and applying to said base coat a clear film-forming composition to form a transparent top coat over the base coat comprising as the clear film-forming composition and/or as the colored film-forming composition the coating composition of claim 12.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1996-05-17	1996-11-16	1997-05-18	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2000-05-17	2000-11-16	2001-05-18	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2004-05-17	2004-11-16	2005-05-18	$7700.00	Window Closed / Lapsed

Crosslinked polymeric microparticles; their method of preparation and use in coating compositions

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