Polyolefin-based resin pre-expanded particles and polyolefin-based resin in-mold expansion molded article comprising polyolefin-based resin pre-expanded particles

Abstract

Polyolefin-based resin pre-expanded particles include a polyolefin-based resin composition including a polyolefin-based resin, a sterically hindered amine ether flame retardant expressed by the general formula (1): R 1 NHCH 2 CH 2 CH 2 NR 2 CH 2 CH 2 NR 3 CH 2 CH 2 CH 2 NHR 4 (1), and a phosphoric ester. The polyolefin-based resin pre-expanded particles are flame retardant polyolefin-based resin pre-expanded particles that can have good in-mold expansion moldability and exhibit excellent flame resistance compared to the conventional pre-expanded particles even when molded into a sample having a higher density or a larger thickness without using a halogen flame retardant, and that do not generate harmful gas during burning.

1 . Polyolefin-based resin pre-expanded particles comprising a polyolefin-based resin composition including:
 a polyolefin-based resin;   a sterically hindered amine ether flame retardant expressed by the following general formula (1):
   R 1 NHCH 2 CH 2 CH 2 NR 2 CH 2 CH 2 NR 3 CH 2 CH 2 CH 2 NHR 4   (1)
 
   (where R 1 , R 2  and one of R 3  and R 4  are an s-triazine moiety T expressed by the following general formula (2):   
       
         
           
           
               
               
           
         
       
       the other of R 3  and R 4  is a hydrogen atom, and in the general formula (2), R 5  is an alkyl group having 1 to 12 carbon atoms and R 6  is a methyl group, a cyclohexyl group, or an octyl group); and
 a phosphoric ester. 
 
     
     
         2 . The polyolefin-based resin pre-expanded particles according to  claim 1 , obtained by dispersing polyolefin-based resin particles composed of the polyolefin-based resin composition into an aqueous dispersion medium in a presence of a blowing agent, heating the dispersion thus obtained under pressure, and releasing the dispersion into a low pressure region. 
     
     
         3 . The polyolefin-based resin pre-expanded particles according to  claim 1 , wherein the phosphoric ester is an aromatic-based phosphoric ester. 
     
     
         4 . The polyolefin-based resin pre-expanded particles according to  claim 2 , wherein the blowing agent is at least one selected from the group consisting of isobutane and normal butane. 
     
     
         5 . The polyolefin-based resin pre-expanded particles according to  claim 2 , wherein the blowing agent is carbon dioxide. 
     
     
         6 . The polyolefin-based resin pre-expanded particles according to  claim 1 , wherein the polyolefin-based resin composition includes 0.01 parts by weight to 20 parts by weight of the sterically hindered amine ether flame retardant expressed by the general formula (1) and 0.01 parts by weight to 10 parts by weight of the phosphoric ester with respect to 100 parts by weight of the polyolefin-based resin. 
     
     
         7 . The polyolefin-based resin pre-expanded particles according to  claim 1 , wherein the polyolefin-based resin is a polypropylene-based resin. 
     
     
         8 . A polyolefin-based resin in-mold expansion molded article produced by in-mold expansion molding of the polyolefin-based resin pre-expanded particles according to  claim 1 . 
     
     
         9 . The polyolefin-based resin pre-expanded particles according to  claim 2 , wherein the phosphoric ester is an aromatic-based phosphoric ester. 
     
     
         10 . The polyolefin-based resin pre-expanded particles according to  claim 2 , wherein the polyolefin-based resin composition includes 0.01 parts by weight to 20 parts by weight of the sterically hindered amine ether flame retardant expressed by the general formula (1) and 0.01 parts by weight to 10 parts by weight of the phosphoric ester with respect to 100 parts by weight of the polyolefin-based resin. 
     
     
         11 . The polyolefin-based resin pre-expanded particles according to  claim 2 , wherein the polyolefin-based resin is a polypropylene-based resin. 
     
     
         12 . The polyolefin-based resin pre-expanded particles according to  claim 3 , wherein the polyolefin-based resin composition includes 0.01 parts by weight to 20 parts by weight of the sterically hindered amine ether flame retardant expressed by the general formula (1) and 0.01 parts by weight to 10 parts by weight of the phosphoric ester with respect to 100 parts by weight of the polyolefin-based resin. 
     
     
         13 . The polyolefin-based resin pre-expanded particles according to  claim 3 , wherein the polyolefin-based resin is a polypropylene-based resin. 
     
     
         14 . The polyolefin-based resin pre-expanded particles according to  claim 9 , wherein the blowing agent is at least one selected from the group consisting of isobutane and normal butane. 
     
     
         15 . The polyolefin-based resin pre-expanded particles according to  claim 9 , wherein the blowing agent is carbon dioxide. 
     
     
         16 . The polyolefin-based resin pre-expanded particles according to  claim 9 , wherein the polyolefin-based resin composition includes 0.01 parts by weight to 20 parts by weight of the sterically hindered amine ether flame retardant expressed by the general formula (1) and 0.01 parts by weight to 10 parts by weight of the phosphoric ester with respect to 100 parts by weight of the polyolefin-based resin. 
     
     
         17 . The polyolefin-based resin pre-expanded particles according to  claim 9 , wherein the polyolefin-based resin is a polypropylene-based resin.