Rohm and Haas Company

Alexander Kowalski

Martin Vogel

Robert Mitchell Blankenship

Joseph J Wilczynski

Ralph Craig Even

Kim Sang Ho

Chuen-Shyong Chou

Ronald W Novak

Steven Scott Edwards

Mark S Frazza

Robert R Raney

Clarence J Neyhart

Frank Thomas Sanderson

Loretta Ann Wieckowski

Roger H Kottke

Cheun-Shyong Chou

An emulsion polymer and a method for preparing the emulsion polymer by the free radical polymerization of at least one first ethylenically unsaturated monomer to form a first emulsion polymer and the subsequent treatment of the first emulsion polymer with a colloidal stabilizer, at least one second ethylenically unsaturated monomer, and a redox system at 20-85&deg; C. is provided.

Emulsion polymers

The present invention is concerned with core and shell polymeric particles having microvoids in the core and one or more channels connecting the microvoids to the exterior of the particle. These particles, or LCAPs are produced by forming a core of polymeric acid, encasing the core in a shell polymer permeable to base, and then neutralizing the core such that the core swells, causing the shell to 'explode' in a controlled fashion. This controlled explosion causes channels to form in the shell. These particles can be used as control release devices for target compounds, to impart reinforcing properties to acrylic films, as an opacifying agent in coating compositions, and as a supplement or replacement of part or all of the pigmentary material or extenders that would otherwise be used in such coating compositions.

Synthesis of latex capsules

Uniformly sized polymer particles of 1-50 .mu.m diameter are made by gradually combining a water-insoluble monomer mixture with an aqueous dispersion of emulsion-polymerized polymer particles in the presence of a dispersion stabilizer and an oil-soluble, free-radical polymerization initiator.

Process for making controlled, uniform-sized particles in the 1 to 50

Binder, coating, and adhesive compositions having surprising film build, flow, leveling, and adhesive wet tack are provided by an aqueous dispersion comprising polymer particles having a central core surrounded by lobes. Also disclosed are the uses and process of preparation of these unique particles.

Multilobals

Multi-stage polymer particles containing one or more void space(s) therein are produced by sequential emulsion polymerization of an essentially low-acid earlier polymer stage, encapsulation of said low-acid polymer stage with at least a final polymer stage, contacting said polymer particles with a non-polymeric carboxylic acid or anhydride to permit the acid or anhydride to be absorbed into said low-acid polymer stage and swelling the polymer particles by contacting the particles with an aqueous base. The low-acid polymer stage is formed by emulsion polymerizing a monomer system comprising ethylenically unsaturated monomer(s) and containing less than 5% by weight of monomer(s) containing acid functionality. The low-acid polymer stage is swubsequently encapsulated by one or more polymer stages by emulsion polymerizing ethylenically unsaturated monomer(s) in the presence of the low-acid polymer stage. The final stage has a glass transition temperature (Tg) of about 50.degree. C. or greater, and the total polymer stages having a Tg of about 50.degree. C. or greater comprise about 60% or more by weight of the polymer particles. A non-polymeric carboxylic acid or anhydride is absorbed into the polymer particles and the resultant particles are contacted with base at a pH sufficient to swell the particles with water at a temperature near or above the Tg of the neat polymer or plasticized polymer of the final polymer stage. When dried the particles contain void space(s) therein which produce(s) opacity in compositions in which the particles are contained.

Multi-stage opacifying polymer particles containing non-polymeric acid

Multi-stage polymer particles containing one or more void space(s) therein are produced by sequential emulsion polymerization of an essentially low-acid earlier polymer stage, encapsulation of said low-acid polymer stage with at least a final polymer stage, contacting said polymer particles with a non-polymeric carboxylic acid to permit the acid to be absorbed into said low-acid polymer stage and swelling the polymer particles by contacting the particles with an aqueous base. The low-acid polymer stage is formed by emulsion polymerizing a monomer system comprising ethylenically unsaturated monomer(s) and containing less than 5% by weight of monomer(s) containing acid functionality. The low-acid polymer stage is subsequently encapsulated by one or more polymer stages by emulsion polymerizing ethylenically unsaturated monomer(s) in the presence of the low-acid polymer stage. The final stage has a glass transition temperature (Tg) of about 50.degree. C. or greater, and the total polymer stages having a Tg of about 50.degree. C. or greater comprise about 60% or more by weight of the polymer particles. A non-polymeric carboxylic acid is absorbed into the polymer particles and the resultant particles are contacted with base at a pH sufficient to swell the particles with water at a temperature near or above the Tg of the neat polymer or plasticized polymer of the final polymer stage. When dried the particles contain void space(s) therein which produce(s) opacity in compositions in which the particles are contained.

Binder, coating, and adhesive compositions having surprising film build, flow, leveling, and adhesive wet tack are provided by an aqueous dispersion comprising polymer particles having a central core surrounded by lobes. Also disclsoed are the uses and process of preparation of these unique particles.

Process for making core-sheath polymer particles containing voids, said particles useful for opacifying, comprising (A) emulsion polymerizing a core from a core monomer system comprised of at least one ethylenically unsaturated monomer containing acid functionality; (B) encapsulating said core with a hard sheath by emulsion polymerizing a sheath monomer system in the presence of said core, said sheath permitting penetration of fixed or permanent bases; (C) swelling at elevated temperature the resultant core-sheath polymer particles with fixed or permanent base so as to produce a dispersion of particles which, when dried, contain a microvoid which causes opacity in compositions in which they are contained, provided that either (1) said sheath comprises at least about 1% acid functional monomer or (2) said swelling takes place in the presence of solvent. Compositions comprising said core-sheath polymer particles are also disclosed.

Production of core-sheath polymer particles containing voids, resulting

The present invention is concerned with the production and use of water-insoluble particulate heteropolymers made by sequential emulsion polymerization in dispersed particles of which a 'core' of a polymeric base is at least partially encased in a 'sheath' polymer that is permeable to an acid, such as acetic acid, adapted to cause swelling of the core by neutralization. The aqueous dispersion of the acid-swollen, base-containing core/sheath particles is useful in making water-base coating compositions, microvoids being formed in cores of the swollen particles in the film during the drying thereof. Thus, the heteropolymer dispersion can serve as an opacifying agent in coating compositions, such as water-base paints, as a supplement or replacement of part or all of the pigmentary material or extenders that would otherwise be used in such coating compositions. For convenience of description herein, the terms 'core', 'sheath', and 'core/sheath polymer' are frequently used to refer to the distinct functional components of the individual polymer particles of the essential 'mode' of the heteropolymers of the present invention even though in actuality, the components of the polymer particles thereof may not have the precise arrangement implied by this terminology.

Sequential heteropolymer dispersion and a particulate material

The present invention is concerned with the production and use of water-insoluble particulate heteropolymers made by sequential emulsion polymerization in dispersed particles of which a 'core' of a polymeric acid is at least partially encased in a 'sheath' polymer that is permeable to a volatile base, such as ammonia or an organic amine, adapted to cause swelling of the core by neutralization. The aqueous dispersion of the acid-containing core/sheath particles is useful in making water-base coating compositions wherein it may serve as the binder or as a part thereof. In that use, the heteropolymer dispersion serves to provide desirable rheological control of the coating compositions when a volatile base is used to at least partially (to a pH of at least 6) neutralize the heteropolymer. Thus, the heteropolymer dispersion can serve as a thickener, or part thereof in coating compositions, such as water-base paints. For convenience of description herein, the terms 'core', 'sheath', and 'core/sheath polymer' are frequently used to refer to the distinct functional components of the individual polymer particles of the essential 'mode' of the heteropolymers of the present invention even though in actuality, the components of the polymer particles thereof may not have the precise arrangement implied by this terminology.

Sequential heteropolymer dispersion and a particulate materal obtainable

The present invention is concerned with the production and use of water-insoluble particulate heteropolymers made by sequential emulsion polymerization in dispersed particles of which a 'core' of a polymeric acid is at least partially encased in a 'sheath' polymer that is permeable to a volatile base, such as ammonia or an organic amine, adapted to cause swelling of the core by neutralization. The aqueous dispersion of the acid-containing core/sheath particles is useful in making water-base coating compositions wherein it may serve as an opacifying agent when a volatile base is used to at least partially (to a pH of at least 6) neutralize the heteropolymer, microvoids being formed in cores of the swollen particles in the film during the drying thereof. Thus, the heteropolymer dispersion can serve as an opacifying agent in coating compositions, such as water-base paints, as a supplement or replacement of part or all of the pigmentary material or extenders that would otherwise be used in such coating compositions. For convenience of description herein, the terms 'core', 'sheath', and 'core/sheath polymr' are frequently used to refer to the distinct functional components of the individual polymer particles of the essential 'mode' of the heteropolymers of the present invention even though in actuality, the components of the polymer particles thereof may not have the precise arrangement implied by this terminology.

The pressure sensitive adhesive of this invention has improved shear resistance while still having good tackiness and stability in a humid atmosphere, it is prepared by solution polymerization, or by other methods, and has carboxylic acid groups therein, an alkoxyalkyl ester of an unsaturated carboxylic acid, an hydroxyalkyl ester of an unsaturated carboxylic acid having at least one hydroxyl functionality and, in many cases, an alkyl acrylate or an alkyl methacrylate. A crosslinker may be used, and the adhesive cured by heat, without destroying the proper relationship of tack and shear resistance.

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Plymouth Meeting, PA, United States of America

Alexander Kowalski