A composite powder containing microstructured particles obtainable by means of a method in which large particles are combined with small particles, wherein the large particles have an average particle diameter within the range from 0.1 μm to 10 mm, the large particles comprise at least one polymer, the small particles are arranged on the surface of the large particles and/or distributed inhomogeneously within the large particles, the small particles comprise sphere-shaped precipitated calcium carbonate particles having an average diameter within the range from 0.05 μm to 50.0 μm, wherein the sphere-shaped calcium carbonate particles are obtainable by means of a method in which
a. a calcium hydroxide suspension is initially charged,
b. carbon dioxide or a carbon dioxide-containing gas mixture is introduced into the suspension from step a. and
c. resultant calcium carbonate particles are separated off,
with 0.3% by weight to 0.7% by weight of at least one aminotrisalkylenephosphonic acid being further added. Preferred application areas of the composite powder encompass its use as additive, especially as polymer additive, as additive substance or starting material for compounding, for the production of components, for applications in medical technology and/or in microtechnology and/or for the production of foamed articles. The invention therefore also provides components obtainable by selective laser sintering of a composition comprising a composite powder according to the invention, except for implants for uses in the field of neurosurgery, oral surgery, jaw surgery, facial surgery, neck surgery, nose surgery and ear surgery as well as hand surgery, foot surgery, thorax surgery, rib surgery and shoulder surgery. The invention also provides the sphere-shaped calcium carbonate particles which can advantageously be used to produce the composite particles according to the invention, and the use thereof.

A resin powder may be superior in passability through pipes and silos, and a method may produce such a resin powder. The resin powder contains a vinyl alcohol polymer, an average particle diameter thereof is 100 to 2,000 μm, and an average value PA of a roundness P by formula (1), of 50 particles arbitrarily extracted from the particles of the resin powder having a particle diameter of 100 to 1,000 μm, is 0.1 to 0.8.

P=(Σ.sub.i=1.sup.Nr.sub.i)/NR  (1)

r.sub.i being a radius of curvature of each particle corner of the 50 particles; R being a maximum inscribed circle radius of the particle; and N being a number of particle corners. If the number of particle corners is 9 or more, the radii of curvature of eight corners, in increasing order from a smallest radius of curvature, are adopted, and N is 8.

Articles having improved properties are disclosed. The articles are formed from a composition obtained by dry blending: a) 70-95 wt. % of a polyolefin polymer selected from polypropylene homopolymers, polypropylene copolymers, polypropylene impact copolymers, and mixtures thereof; and b) 5 to 30 wt. % of a free-flowing styrenic block copolymer coated with a functional dusting agent having a maximum particle size of 100 microns. The free-flowing styrenic block copolymer requires less than 400 lbs/ft.sup.2 of force to break in a blocking test. The molded article has improved impact strength and haze.

The present invention relates to compositions comprising fibrillated cellulose and one or more nonionic cellulose ethers. Such compositions were found to be able to modify the rheology of an aqueous medium, also when the aqueous medium comprises salts and surfactants, whereby specific formulations shows desirable thixotropic thickening of the aqueous medium.

A resin powder for three-dimensional molding includes ethylene-propylene copolymer particles. The volume average particle size of the ethylene-propylene copolymer particles is within a range of 5 to 200 μm. The ethylene content molar ratio (ethylene/(ethylene+propylene)) in the ethylene-propylene copolymer particles is within a range of 0.001 to 0.04. The melt flow rate (MFR) is within a range of 3 to 40 g/10 min at 230° C.

An object of the present invention is to produce composite resin particles in which the original physical properties of PTFE derived from fine powder are maintained, and the present invention provides a method for producing composite resin particles, wherein the method includes: a first step in which fine powder containing polytetrafluoroethylene obtained by emulsion polymerization is pulverized in the presence of a ketone-based solvent; a second step in which the pulverized fine powder and a carbon nanomaterial are dispersed in the ketone-based solvent to produce a composite resin particles dispersion; a third step in which the composite resin particles are produced by removing the ketone-based solvent from the composite resin particle dispersion; and wherein the fine powder is pulverized so as to have an average particle diameter of 50 μm or less, and a temperature of the ketone-based solvent used in the first step is set to 20° C. or less.

The invention relates to a composition based on a thermoplastic fluoropolymer powder, in particular on polyvinylidene fluoride (PVDF) with improved flowability, particularly suitable for manufacturing parts by 3D laser sintering. The invention also relates to a method for agglomerating powder layer by layer, by melting or sintering using said composition. The invention finally relates to a three-dimensional article obtained by implementing said method.

A composite powder containing microstructured particles having inhibitory calcium carbonate, obtainable by means of a method in which large particles are combined with small particles, wherein the large particles have an average particle diameter within the range from 0.1 μm to 10 mm, the large particles comprise at least one polymer, the small particles are arranged on the surface of the large particles and/or distributed inhomogeneously within the large particles, the small particles comprise calcium carbonate particles, the small particles have an average particle size within the range from 0.01 μm to 1.0 mm,
wherein the small particles are obtainable by means of a method in which calcium carbonate particles are coated with a composition comprising, based on its total weight, at least 0.1% by weight of at least one weak acid.

Preferred application areas of the composite powder encompass its use as additive, especially as polymer additive, as additive substance or starting material for compounding, for the production of components, for applications in medical technology and/or in microtechnology and/or for the production of foamed articles.

The invention therefore also provides components obtainable by selective laser sintering of a composition comprising a composite powder according to the invention, except for implants for uses in the field of neurosurgery, oral surgery, jaw surgery, facial surgery, neck surgery, nose surgery and ear surgery as well as hand surgery, foot surgery, thorax surgery, rib surgery and shoulder surgery.

A process prepares a polymer powder, with a D50 particle size from 40 to 200 μm and a Hausner factor of 1.25 or less, by freeze drying and subsequent loosening up of an aqueous polymer dispersion containing 15 to 50% by weight of a polymer. The polymer is polymerized from 10 to 30% by weight of methyl methacrylate, 50 to 70% by weight of methyl acrylate, and 5 to 15% by weight of methacrylic acid.

A process prepares a polymer powder, with a D50 particle size from 40 to 200 μm and a Hausner factor of 1.25 or less, by freeze drying and subsequent loosening up of an aqueous polymer dispersion containing 15 to 50% by weight of a polymer. The polymer is polymerized from 10 to 30% by weight of methyl methacrylate, 50 to 70% by weight of methyl acrylate, and 5 to 15% by weight of methacrylic acid.