The present invention relates to porous crosslinked polymeric microbeads having cavities joined by interconnecting pores wherein at least some of the cavities at the interior of each microbead communicate with the surface of the microbead. The present invention also relates to a process for producing a porous, crosslinked polymeric microbead as well as the product of this process. This process involves combining an oil phase with an aqueous discontinuous phase to form an emulsion adding the emulsion to an aqueous suspension medium to form an oil-in-water suspension of dispersed emulsion droplets, and polymerizing the emulsion droplets to form microbeads. At least 10 % of the microbeads produced in accordance with the present invention are substantially spherical or substantially ellipsoidal or a combination of the two.

Polymeric microbeads and method of preparation

The invention relates to a process for the gel or surface postcrosslinking of water-absorbing polymers in which the polymers are treated with a surface postcrosslinking solution and during or after the treatment are postcrosslinked and dried by means of an increase in temperature, the crosslinker being a compound of the formula in which R1 and R2 independently of one another are H, hydroxyl, phenyl or C1-C6-alkyl, R3 is hydrogen, C1-C12-alkyl, C1-C12-alkenyl or C6-C12-aryl and R4 and R5 independently of one another are C1 -C 12-alkyl, C1 -C 12-alkenyl, C6 -C 12-aryl, hydroxyl, C1 -C 12-alkoxy or hydrogen, dissolved in an inert solvent, to water-absorbing polymers which can be obtained by said process, and to their use in hygiene articles, packaging materials and nonwovens.

Process for crosslinking hydrogels with bis- and poly-2- oxazolidinones

A thermosetting powder coating composition according to the present invention comprises as binder a co-reactable particulate mixture of a carboxylic acid-functional polyester component and a curing agent having groups reactive with carboxylic acid groups, characterized in that the carboxylic acid-functional component comprises a semi-crystalline polyester having an acid value of from 10 to 70 mg KOH/g and a hydroxy value of no more than 11 mg KOH/g. Generally the semi-crystalline polyester has one or more Tg values less than 55° C., a sharp melting point of 50 to 200° C. and preferably a number average molecular weight of at least 1600. The composition may, if desired, include an amorphous polyester and the curing agent may be, for example, an epoxy resin or a bis(beta-hydroxyalkylamide).

Powder coating composition of semi-crystalline polyester and curing agent

Provided are novel thermosetting powder coating compositions which are useful for coating metal articles and protecting such articles from acidic corrosion. The compositions are comprised of an epoxy containing acrylic copolymer crosslinked with both an aliphatic dibasic acid and a blocked polyisocyanate.

Thermosetting powder coating compositions

Methods are described that have the capability of producing submicron/nanoscale particles, in some embodiments dispersible, at high production rates. In some embodiments, the methods result in the production of particles with an average diameter less than about 75 nanometers that are produced at a rate of at least about 35 grams per hour. In other embodiments, the particles are highly uniform. These methods can be used to form particle collections and/or powder coatings. Powder coatings and corresponding methods are described based on the deposition of highly uniform submicron/nanoscale particles.

Nanoparticle production and corresponding structures

A powder coating composition of the invention comprises a film-forming polymeric component having a d(v,50) in the range of from 25 to 50 microns or a d(v,70) in the range of from 25 to 70 microns, which composition incorporates by dry-blending at least one appearance-modifying additive component and a further component comprising wax-coated silica or consisting of alumina together with aluminium hydroxide. The appearance-modifying additive may be a gloss-reducing component, a texturing component, a metallic or mica component, a colouring pigment, or a further film-forming polymeric material compatible with the first film-forming polymeric material and differing in colouration therefrom, and the further additive may be alumina together with aluminium hydroxide or wax-coated silica together with alumina and/or with aluminium hydroxide or wax-coated silica. Preferably, no more than 70 % by volume of the particles in the film-forming polymeric material are less than 50 microns. A kit of the invention comprises the individual additive components prior to mixing. The kit allows for the flexibl production of a variety of finishes from a gloss powder coating composition, for example a matt or textured or metallic or sparkle finish or a matt textured finish, a matt metallic finish, an antique finish or a contrast texture or metallic sparkle finish.

Powder coating compositions

A process for forming a coating on a conductive substrate, which comprises establishing a fluidized bed of a powder coating composition, in which the mechanism for particle charging is tribostatic charging immersing the substrate wholly or partly within the said fluidized bed, applying a voltage to the substrate for at least part of the period of immersion, whereby particles of the powder coating composition adhere to the substrate, withdrawing the substrate from the fluidized bed and forming the adherent particles into a continuous coating over at least part of the substrate. The process enables the coating of substrate areas which, because of the Faraday cage effect, are inaccessible in conventional electrostatic coating processes, and also enables the formation of thinner coatings than are obtainable by conventional fluidized-bed processes.

Ring John

Papers

Powder coating compositions

Fluidized bed powder coating process utilizing tribostatic charging