(meth)acrylate polymer, a resin composition and a shaped article

Abstract

Disclosed is a (meth)acrylate polymer having a volume average primary particle size of 0.520 to 3.00 μm, a peak temperature of tan δ in the range of −100 to 0° C., determined with dynamic viscoelasticity measurement, of −40° C. or below, a peak height of tan δ in the range of −100 to 0° C., determined with dynamic viscoelasticity measurement, of 0.300 or more, and an acetone-insoluble component of 99% by mass of more. This polymer has excellent dispersibility of primary particles in a resin, excellent storage stability of a resin composition obtained, and excellent insulating properties and reduction in elastic modulus of a molded article obtained.

1 . A (meth)acrylate polymer having a volume average primary particle size of 0.520 to 3.00 μm, a peak temperature of tan δ in the range of −100 to 0° C., determined with dynamic viscoelasticity measurement, of −40° C. or below, a peak height of tan δ in the range of −100 to 0° C., determined with dynamic viscoelasticity measurement, of 0.300 or more, and an acetone-insoluble component of 99% by mass or more. 
     
     
         2 . A resin composition comprising the (meth)acrylate polymer according to  claim 1  and a resin. 
     
     
         3 . The resin Composition according to  claim 2 , wherein the resin is an epoxy resin. 
     
     
         4 . A shaped article obtained with shaping of the resin composition according to  claim 2  or  3 . 
     
     
         5 . A sealing material for semiconductors comprising the (meth)acrylate polymer according to  claim 1  and a resin. 
     
     
         6 . An adhesive comprising the (meth)acrylate polymer according to  claim 1  and a resin. 
     
     
         7 . A process for producing the (meth)acrylate polymer comprising polymerization of monomer mixture (b) in the presence of rubbery (meth)acrylate polymer (A), wherein monomer mixture (b) comprises cross-linkable monomer (b1), the content of rubbery (meth)acrylate polymer (A) is 81 to 98% by mass and the content of monomer mixture (b) is 2 to 19% by mass (total of rubbery (meth)acrylate polymer (A) and monomer mixture (b) is 100% by mass), and the (meth)acrylate polymer has the volume average primary particle size of 0.520 to 3.00 μm and the peak temperature of tan δ in the range of −100 to 0° C., determined with dynamic viscoelasticity measurement, of −40° C. or below. 
     
     
         8 . A process for producing a powdery (meth)acrylate polymer comprising polymerization of monomer mixture (b) in the presence of rubbery (meth)acrylate polymer (A) and spray-drying of a latex of the (meth)acrylate polymer, wherein monomer mixture (b) comprises cross-linkable monomer (b1), the content of rubbery (meth)acrylate polymer (A) is 81 to 98% by mass and the content of monomer mixture (b) is 2 to 19% by mass (total of rubbery (meth)acrylate polymer (A) and monomer mixture (b) is 100% by mass), and the (meth)acrylate polymer has the volume average primary particle size of 0.520 to 3.00 μm and the peak temperature of tan δ in the range of −100 to 0° C., determined with dynamic viscoelasticity measurement, of −40° C. or below. 
     
     
         9 . The process for producing the powdery (meth)acrylate polymer according to  claim 8 , wherein the content of each of metal ions in the powdery (meth)acrylate polymer extracted with hot water extraction is 10 ppm or less. 
     
     
         10 . The process for producing the powdery (meth)acrylate polymer according to  claim 8 , wherein the content of sulfate ion in the powdery (meth)acrylate polymer extracted with hot water extraction is 500 ppm or less.