Process for producing resin composition and process for producing molded article

Abstract

A medical resin composition is produced by mixing a powder of a polymer (A) comprising repeating units having an ester group and a liquid of a vinyl ester monomer (B) having 6 or more carbon atoms to increase a viscosity and, according to demand, further performing a polymerization reaction. The thus produced resin composition inhibits leaching of irritative substances, reduces any adverse effects on the human body by endocrine disruptors, etc. and can be prepared with high operational efficiency. The resin composition is suitably used as a dental resin composition such as a tissue conditioner, a functional impression material, a lining material, a denture base material or a mouth piece material.

1 . A process for producing a resin composition comprising mixing 100 parts by weight of a powder of a polymer (A) comprising repeating units having an ester group and having a weight average molecular weight of from 5,000 to 2,000,000, and from 20 to 200 parts by weight of a liquid of a vinyl ester monomer (B) having 6 or more carbon atoms and having a plurality of functional groups in the molecule to increase a viscosity. 
   
   
       2 . The process for producing a resin composition according to  claim 1 , wherein the polymer (A) is a poly(alkyl(meth)acrylate) (A1). 
   
   
       3 . The process for producing a resin composition according to  claim 1 , wherein the vinyl ester monomer (B) is a vinyl carboxylate monomer (61). 
   
   
       4 . The process for producing a resin composition according to  claim 1 , wherein the vinyl ester monomer (B) has two or more vinyl groups in the molecule. 
   
   
       5 . The process for producing a resin composition according to  claim 1 , wherein the powder of the polymer (A) has an average particle diameter of from 2 to 200 μm. 
   
   
       6 . The process for producing a resin composition according to  claim 1 , further comprising adding and mixing a polymerization initiator (C) to increase the viscosity. 
   
   
       7 . The process for producing a resin composition according to  claim 1 , wherein in a spreading test comprising sandwiching 1 mL of a resin composition obtained by mixing between glass plates and applying a load of 100 g, where a diameter of the resin composition spread after completion of the test is 30 mm, the time from mixing of the components (A) and (B) to start of the load application is from 3 to 8 minutes. 
   
   
       8 . The process for producing a resin composition according to  claim 1 , wherein the resin composition is a medical resin composition. 
   
   
       9 . The process for producing a resin composition according to  claim 8 , wherein the medical resin composition is a dental resin composition which serves as at least one material selected from the group consisting of a tissue conditioner, a functional impression material, a lining material, a denture base material and a mouth piece material. 
   
   
       10 . A process for producing a dental resin composition which serves as at least one material selected from the group consisting of a tissue conditioner, a functional impression material and a lining material and which is to be inserted into an oral cavity, comprising mixing 100 parts by weight of a powder of a poly(alkyl(meth)acrylate) (A1) having a weight average molecular weight of from 5,000 to 2,000,000 and having an average particle diameter of from 2 to 200 gm and from 20 to 200 parts by weight of a liquid of a vinyl carboxylate monomer (B1) having 6 or more carbon atoms and having a plurality of functional groups in the molecule to increase the viscosity. 
   
   
       11 . A process for producing a molded article comprising:
 mixing 100 parts by weight of a powder of a polymer (A) comprising repeating units having an ester group and having a weight average molecular weight of from 5,000 to 2,000.000, and from 20 to 200 parts by weight of a liquid of a vinyl ester monomer (B) having 6 or more carbon atoms and having a plurality of functional groups in the molecule to increase a viscosity, and   molding it after increasing of a viscosity.   
   
   
       12 . The process for producing a molded article according to  claim 11 , wherein when the molded article is immersed in water at 37° C., a Shore C hardness (H7) measured seven days after start of immersion is from 0.8 to 1.2 times a Shore C hardness (H) measured one day after start of immersion. 
   
   
       13 . The process for producing a molded article according to  claim 11 , further comprising performing a polymerization reaction after molding.