Resin powder for dermatologic composition, skin cleansing agent and cosmetic composition using the powder, and preparation process of the powder

Abstract

Provided is a resin powder for a dermatologic composition composed of resin particles having an average volume particle size of 2.0 to 20.0 μm, a shape factor SF1 of 110 to 140 and an average volume particle size distribution GSDv of 1.3 or less. Also disclosed are a skin cleansing composition and a cosmetic composition containing the resin powder, and a preparation process of the resin powder.

What is claimed is:  
     
         1 . A resin powder for a dermatologic composition, which comprises resin particles having an average volume particle size of 2.0 to 20.0 μm, a shape factor SF1 of 110 to 140 and an average volume particle size distribution GSDv of 1.3 or less.  
     
     
         2 . The resin powder of  claim 1 , wherein the resin particles further have a surfaceness index of 2.0 or less.  
     
     
         3 . The resin powder of  claim 1 , wherein the resin particles further have an average number particle size distribution GSDp of 1.5 or less.  
     
     
         4 . The resin powder of  claim 1 , wherein a volumetric ratio of the resin particles having a volume particle size of 20 μm or greater is 3% or less.  
     
     
         5 . The resin powder of  claim 1 , wherein the resin has a number-average molecular weight of 3,000 to 20,000.  
     
     
         6 . The resin powder of  claim 1 , wherein the resin has a weight-average molecular weight of 6,000 to 100,000.  
     
     
         7 . The resin powder of  claim 1 , wherein the resin has a glass transition temperature ranging from 40 to 100° C.  
     
     
         8 . The resin powder of  claim 1 , which have a compaction ratio of 0.6 or less.  
     
     
         9 . The resin powder of  claim 1 , wherein the resin particles have a water content of 3 wt. % or less.  
     
     
         10 . The resin powder of  claim 1 , wherein a volatile content in the resin particles is 100 ppm or less.  
     
     
         11 . The resin powder of  claim 1 , wherein the resin constituting the resin particles has an acid value ranging from 1.0 to 20 mg/KOH/g.  
     
     
         12 . The resin powder of  claim 1 , wherein a solution, obtained by dissolving 1 g of the resin powder in 3 g of acetone, adding 25 g of deionized water to the resulting solution to give a precipitate and filtering the precipitate thus formed has a surface tension of 20 mN or greater.  
     
     
         13 . The resin powder of  claim 1 , wherein a solution, obtained by dissolving 1 g of the resin powder in 3 g of acetone, adding 25 g of deionized water to the resulting solution to give a precipitate and filtering the precipitate thus formed has a conductivity of 100 μS or less.  
     
     
         14 . The resin powder of  claim 12 , wherein the solution has a conductivity of 100 μS or less.  
     
     
         15 . The resin powder of  claim 12 , wherein the resin particles has other fine particles adhered thereto.  
     
     
         16 . The resin powder of  claim 15 , wherein the resin particles and the fine particles are used in combination so as to satisfy the following formula: (volume average particle size of the resin particles)/(volume average particle size of the fine particles)≧2.  
     
     
         17 . The resin powder of  claim 15 , wherein a weak adhesive strength ratio of the fine particles to the resin particles is 90% or less.  
     
     
         18 . A cosmetic composition comprising a resin powder for a dermatologic composition as claimed in  claim 1 .  
     
     
         19 . The cosmetic composition of  claim 18 , wherein the content of the resin powder is from 0.1 to 90 wt. % of the composition.  
     
     
         20 . A skin cleansing composition, comprising a resin powder for a dermatologic composition as claimed in  claim 1 .  
     
     
         21 . The skin cleansing composition of  claim 20 , wherein the content of the resin powder is from 0.1 to 90 wt. % of the composition.  
     
     
         22 . A process for preparing a resin powder for a dermatologic composition as claimed in claim  1 , which comprises preparing a dispersion of resin particles by emulsion polymerization and allowing the resin particles to undergo agglomeration.