01-09-2022 дата публикации
Номер: US20220275191A1
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. 1. A resin powder , consisting of particles ,wherein the resin powder comprises a vinyl alcohol polymer,wherein an average particle diameter of the particles is in a range of from 100 to 2,000 μm, and {'br': None, 'i': P', 'r', 'NR, 'sub': i=1', 'i, 'sup': 'N', '=(Σ)/\u2003\u2003(1),'}, 'wherein 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 in a range of from 100 to 1,000 μm, is in a range of from 0.1 to 0.8wherein, in the formula (1),{'sub': 'i', 'ris a curvature radius of each corner of a particle of the 50 particles arbitrarily extracted,'}R is a maximum inscribed circle radius of the particle, andN is a number of corners of the particle,wherein, when a number of corners of the particle is 9 or more, radii of curvature of eight corners, in increasing order from a smallest radius of curvature, are adopted, and N is set to 8.2. The powder of claim 1 , wherein the vinyl alcohol polymer has a viscosity-average degree of polymerization in a range of from 200 to 5 claim 1 ,000 claim 1 , andwherein the vinyl alcohol polymer a degree of saponification in a range of from 35 to 99.99 mol %.3. The powder of claim 1 , wherein the average particle diameter is in a range of from 100 to 1 claim 1 ,000 μm claim 1 , and satisfying inequality (2):{'br': None, 'i': 'PA×S≥', '18\u2003\u2003(2),'}wherein, in the inequality (2), S is a degree of saponification (mol %) of the vinyl alcohol polymer.4. The powder of claim 1 , wherein a percentage content of ...
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