Reinforcing sheet for resin molded article, reinforced structure of resin molded article, and reinforcing method

Abstract

A reinforcing sheet for a resin molded article includes a constraining layer and a reinforcing layer laminated on the constraining layer. When the reinforcing sheet for a resin molded article is attached to a polypropylene plate having a thickness of 2.0 mm and is heated at 80° C. for 10 minutes, the bending strength at a displacement of 1 mm of the resulting sheet after the heating is 3 N or more and the maximum bending strength thereof is 30 N or more, and a high-temperature adhesion retention ratio R as determined by the following formula is 80% or more. High-temperature adhesion retention ratio R=(Adhesive force A1000h after heating at 100° C. for 1000 hours/Adhesive force A1h after heating at 100° C. for 1 hour)×100.

1 . A reinforcing sheet for a resin molded article comprising:
 a constraining layer and a reinforcing layer laminated on the constraining layer, wherein   when the reinforcing sheet for a resin molded article is attached to a polypropylene plate having a thickness of 2.0 mm and is heated at 80° C. for 10 minutes, the bending strength at a displacement of 1 mm of the resulting sheet after the heating is 3 N or more and the maximum bending strength thereof is 30 N or more, and a high-temperature adhesion retention ratio R as determined by the following formula is 80% or more.
   High-temperature adhesion retention ratio  R =(Adhesive force  A   1000h  after heating at 100° C. for 1000 hours/Adhesive force  A   1h  after heating at 100° C. for 1 hour)×100
 
   Adhesive force A 1000h  after heating at 100° C. for 1000 hours: the adhesive force with respect to a polypropylene plate, which is obtained by attaching the reinforcing layer to the polypropylene plate to be heated at 80° C. for 10 minutes and then heated at 100° C. for 1000 hours to be thereafter measured by a 90-degree peeling test based on JIS Z0237 (in 2000) at a peeling rate of 300 mm/min.   Adhesive force A 1h  after heating at 100° C. for 1 hour: the adhesive force with respect to a polypropylene plate, which is obtained by attaching the reinforcing layer to the polypropylene plate to be heated at 80° C. for 10 minutes and then heated at 100° C. for 1 hour to be thereafter measured by a 90-degree peeling test based on JIS Z0237 (in 2000) at a peeling rate of 300 mm/min.   
     
     
         2 . The reinforcing sheet for a resin molded article according to  claim 1 , wherein
 an adhesive force A 10m  with respect to a polypropylene plate, which is obtained by attaching the reinforcing layer to the polypropylene plate to be heated at 80° C. for 10 minutes to be thereafter measured by a 90-degree peeling test based on JIS Z0237 (in 2000) at a peeling rate of 300 mm/min, is 15 N/25 mm or more.   
     
     
         3 . The reinforcing sheet for a resin molded article according to  claim 1 , wherein
 the adhesive force A 1h  after heating at 100° C. for 1 hour is 50 N/25 mm or more.   
     
     
         4 . The reinforcing sheet for a resin molded article according to  claim 1 , wherein
 the storage elastic modulus of the reinforcing layer at 25° C. is 500 kPa or more and that at 80° C. is 500 kPa or less.   
     
     
         5 . The reinforcing sheet for a resin molded article according to  claim 1 , wherein
 an adhesive force A 0  at the time of normal temperature with respect to a polypropylene plate, which is measured by a 90-degree peeling test based on JIS Z0237 (in 2000) at a peeling rate of 300 mm/min, is 0.3 N/25 mm or more.   
     
     
         6 . The reinforcing sheet for a resin molded article according to  claim 1 , wherein
 the reinforcing layer is formed of a thermally adhesive type adhesive composition.   
     
     
         7 . The reinforcing sheet for a resin molded article according to  claim 6 , wherein
 the adhesive composition contains a hydrogenated polymer of a monomer containing conjugated dienes.   
     
     
         8 . The reinforcing sheet for a resin molded article according to  claim 7 , wherein
 the adhesive composition further contains a tackifier.   
     
     
         9 . The reinforcing sheet for a resin molded article according to  claim 8 , wherein
 the tackifier contains an alicyclic saturated hydrocarbon resin.   
     
     
         10 . The reinforcing sheet for a resin molded article according to  claim 9 , wherein
 the tackifier further contains a terpene resin.   
     
     
         11 . The reinforcing sheet for a resin molded article according to  claim 8 , wherein
 the mixing ratio of the tackifier is 40 to 200 parts by weight with respect to 100 parts by weight of the hydrogenated polymer.   
     
     
         12 . A reinforced structure of a resin molded article comprising:
 a reinforcement of a resin molded article obtained by attaching a reinforcing sheet for a resin molded article including a constraining layer and a reinforcing layer laminated on the constraining layer to the resin molded article to be then heated at 80° C. or more to bring the reinforcing sheet for a resin molded article into close contact with the resin molded article, wherein   when the reinforcing sheet for a resin molded article is attached to a polypropylene plate having a thickness of 2.0 mm and is heated at 80° C. for 10 minutes, the bending strength at a displacement of 1 mm of the resulting sheet after the heating is 3 N or more and the maximum bending strength thereof is 30 N or more, and a high-temperature adhesion retention ratio R as determined by the following formula is 80% or more.
   High-temperature adhesion retention ratio  R =(Adhesive force  A   1000h  after heating at 100° C. for 1000 hours/Adhesive force  A   1h  after heating at 100° C. for 1 hour)×100
 
   Adhesive force A 1000h  after heating at 100° C. for 1000 hours: the adhesive force with respect to a polypropylene plate, which is obtained by attaching the reinforcing layer to the polypropylene plate to be heated at 80° C. for 10 minutes and then heated at 100° C. for 1000 hours to be thereafter measured by a 90-degree peeling test based on JIS Z0237 (in 2000) at a peeling rate of 300 mm/min.   Adhesive force A 1h  after heating at 100° C. for 1 hour: the adhesive force with respect to a polypropylene plate, which is obtained by attaching the reinforcing layer to the polypropylene plate to be heated at 80° C. for 10 minutes and then heated at 100° C. for 1 hour to be thereafter measured by a 90-degree peeling test based on JIS Z0237 (in 2000) at a peeling rate of 300 mm/min.   
     
     
         13 . The reinforced structure of the resin molded article according to  claim 12 , wherein
 the reinforcing sheet for a resin molded article is heated at 80° C. or more in advance and then, the reinforcing sheet for a resin molded article is attached to the resin molded article.   
     
     
         14 . A reinforcing method of a resin molded article comprising the steps of:
 attaching a reinforcing sheet for a resin molded article including a constraining layer and a reinforcing layer laminated on the constraining layer to the resin molded article and   reinforcing the resin molded article by heating the reinforcing sheet for a resin molded article and/or the resin molded article at 80° C. or more to bring the reinforcing sheet for a resin molded article into close contact with the resin molded article, wherein   when the reinforcing sheet for a resin molded article is attached to a polypropylene plate having a thickness of 2.0 mm and is heated at 80° C. for 10 minutes, the bending strength at a displacement of 1 mm of the resulting sheet after the heating is 3 N or more and the maximum bending strength thereof is 30 N or more, and a high-temperature adhesion retention ratio R as determined by the following formula is 80% or more.
   High-temperature adhesion retention ratio  R =(Adhesive force  A   1000h  after heating at 100° C. for 1000 hours/Adhesive force  A   1h  after heating at 100° C. for 1 hour)×100
 
   Adhesive force A 1000h  after heating at 100° C. for 1000 hours: the adhesive force with respect to a polypropylene plate, which is obtained by attaching the reinforcing layer to the polypropylene plate to be heated at 80° C. for 10 minutes and then heated at 100° C. for 1000 hours to be thereafter measured by a 90-degree peeling test based on JIS Z0237 (in 2000) at a peeling rate of 300 mm/min.   Adhesive force A 1h  after heating at 100° C. for 1 hour: the adhesive force with respect to a polypropylene plate, which is obtained by attaching the reinforcing layer to the polypropylene plate to be heated at 80° C. for 10 minutes and then heated at 100° C. for 1 hour to be thereafter measured by a 90-degree peeling test based on JIS Z0237 (in 2000) at a peeling rate of 300 mm/min.   
     
     
         15 . The reinforcing method of the resin molded article according to  claim 14 , wherein
 in the step of attaching the reinforcing sheet for a resin molded article to the resin molded article, the reinforcing sheet for a resin molded article is heated at 80° C. or more in advance and then, the reinforcing sheet for a resin molded article is attached to the resin molded article.