Synthetic resin emulsion powder

Abstract

Disclosed is a synthetic resin emulsion powder obtained by spray-drying a composition that comprises an emulsion (A) where the dispersoid is a polymer that having one or more unsaturated monomer units selected from ethylenic unsaturated monomers and dienic monomers, and a polyvinyl alcohol (B) having, in the molecule, from 1 to 12 mol % of ethylene units. The emulsion powder has good redispersibility and good water resistance. Its redispersion well form good films and has good storage stability at low temperatures. The emulsion powder is favorable for additives to hydraulic substances, as it well disperses in hydraulic substances such as cement mortar and gives hardened articles of high mechanical strength. The emulsion powder is also favorable for joint materials for hydraulic substances, as its adhesiveness and durability are both good and gives jointed articles of high mechanical strength.

1 - 12 . (canceled) 
   
   
       13 . A synthetic resin emulsion powder, obtained by:
 (i) forming a polymer emulsion (A) comprising a dispersant and a dispersoid,   (ii) mixing the polymer emulsion (A) with a polyvinyl alcohol (C) to form an emulsion composition,   (iii) drying the emulsion composition,   wherein the dispersoid is a polymer having one or more unsaturated monomer units selected from the group consisting of ethylenic unsaturated monomers and dienic monomers, and   wherein the polyvinyl alcohol (C) has an ethylene unit content of from 1 to 12 mol %.   
   
   
       14 . The synthetic resin emulsion powder as claimed in  claim 13 , wherein the polyvinyl alcohol (C) is not chemically bonded with the dispersoid. 
   
   
       15 . The synthetic resin emulsion powder as claimed in  claim 13 , wherein the ethylene unit content of the dispersant is from 2 to 12 mol %. 
   
   
       16 . The synthetic resin emulsion powder as claimed in  claim 13 , wherein the ethylene unit content of the dispersant is from 5 to 10 mol %. 
   
   
       17 . The synthetic resin emulsion powder as claimed in  claim 13 , wherein the ethylene unit content of the dispersant is from 1.5 to 5 mol %. 
   
   
       18 . The synthetic resin emulsion powder as claimed in  claim 13 , wherein the polyvinyl alcohol (C) is a polyvinyl alcohol having a 1,2-glycol bond content of at least 1.9 mol %. 
   
   
       19 . The synthetic resin emulsion powder as claimed in  claim 13 , comprising from 1 to 50 parts by weight of the polyvinyl alcohol (C) relative to 100 parts by weight of the dispersoid. 
   
   
       20 . The synthetic resin emulsion powder as claimed in  claim 13 , further comprising an inorganic powder. 
   
   
       21 . The synthetic resin emulsion powder as claimed in  claim 13  for which the drying is spray-drying. 
   
   
       22 . An additive or joint material for hydraulic substances, comprising the synthetic resin powder of  claim 13 .