Adhesive layer and adhesive sheet

Abstract

There are provided a pressure-sensitive or bonding adhesive layer that, when a repairing or reinforcing sheet is laminated onto concrete, can temporarily fix the sheet to the concrete to facilitate the repair or reinforcement of the concrete, and a pressure-sensitive or bonding adhesive sheet that includes the pressure-sensitive or bonding adhesive layer. The pressure-sensitive or bonding adhesive layer contains an acrylic resin having a glass transition temperature of 15° C. or below and further contains a liquid epoxy resin, a solid epoxy resin, and a curing agent. A pressure-sensitive or bonding adhesive sheet includes a pressure-sensitive or bonding adhesive layer and a separation film or a repairing or reinforcing sheet provided on one surface of the pressure-sensitive or bonding adhesive layer.

1 . A pressure-sensitive or bonding adhesive layer comprising:
 an acrylic resin having a glass transition temperature of 15° C. or below;   a liquid epoxy resin;   a solid epoxy resin; and   a curing agent configured to cure the liquid epoxy resin and the solid epoxy resin.   
     
     
         2 . The pressure-sensitive or bonding adhesive layer according to  claim 1 , wherein
 a pressure sensitive adhesive strength of the layer is greater than or equal to 0.4N/25 mm and less than or equal to 5N/25 mm.   
     
     
         3 . The pressure-sensitive or bonding adhesive layer according to  claim 1 , wherein
 the content of the acrylic resin is greater than or equal to 4% by mass and less than or equal to 50% by mass based on the total amount of the acrylic resin, the liquid epoxy resin and the solid epoxy resin.   
     
     
         4 . The pressure-sensitive or bonding adhesive layer according to  claim 1 , wherein
 the content of the liquid epoxy resin is greater than or equal to 20% by mass and less than or equal to 80% by mass based on the total amount of the liquid epoxy resin and the solid epoxy resin.   
     
     
         5 . The pressure-sensitive or bonding adhesive layer according to  claim 1 , wherein
 the liquid epoxy resin and the solid epoxy resin include at least one selected from the group of a bisphenol A epoxy resin and a bisphenol F epoxy resin.   
     
     
         6 . A pressure-sensitive or bonding adhesive sheet comprising:
 the pressure-sensitive or bonding adhesive layer according to  claim 1 ; and   a first separation film provided to a first surface of the layer.   
     
     
         7 . The pressure-sensitive or bonding adhesive sheet according to  claim 6 , further comprising
 a second separation film provided to a second surface of the layer.   
     
     
         8 . A pressure-sensitive or bonding adhesive sheet comprising:
 the pressure-sensitive or bonding adhesive layer according to  claim 1 ; and   a repairing or reinforcing sheet provided to a first surface of the layer.   
     
     
         9 . The pressure-sensitive or bonding adhesive sheet according to  claim 8 , further comprising
 a separation film provided to a second surface of the layer.   
     
     
         10 . The pressure-sensitive or bonding adhesive layer according to  claim 1 , wherein
 the acrylic resin includes copolymers of methacrylate-acrylate-methacrylate.   
     
     
         11 . The pressure-sensitive or bonding adhesive layer according to  claim 1 , wherein
 the acrylic resin has a mass average molecular weight in the range of 150,000 to 1,500,000.   
     
     
         12 . The pressure-sensitive or bonding adhesive layer according to  claim 1 , wherein
 the liquid epoxy resin has a mass average molecular weight in the range of 300 to 2,000 and an epoxy equivalent of 100 to 800.   
     
     
         13 . The pressure-sensitive or bonding adhesive layer according to  claim 1 , wherein
 the solid epoxy resin has a mass average molecular weight in the range of 300 to 5,000 and an epoxy equivalent of 100 to 2,200.   
     
     
         14 . The pressure-sensitive or bonding adhesive layer according to  claim 1 , wherein
 the curing agent is a latent curing agent.   
     
     
         15 . The pressure-sensitive or bonding adhesive layer according to  claim 1 , wherein
 the curing agent includes a combination of a photobase generator curing catalyst and either a mercapto group-containing curing agent or a phenolic hydroxyl group-containing curing agent.   
     
     
         16 . The pressure-sensitive or bonding adhesive layer according to  claim 1 , wherein
 the layer has a thickness greater than or equal to 150 μm and less than or equal to 500 μm.   
     
     
         17 . The pressure-sensitive or bonding adhesive layer according to  claim 8 , wherein
 the repairing or reinforcing sheet includes a fiber material.   
     
     
         18 . A pressure-sensitive or bonding adhesive sheet comprising:
 a first pressure-sensitive or bonding adhesive layer according to  claim 1  having a first surface;   a second pressure-sensitive or bonding adhesive layer according to  claim 1  having a first surface; and   a repairing or reinforcing sheet disposed between the first and second pressure-sensitive or bonding adhesive layers so as to contact the first surface of the first pressure-sensitive or bonding adhesive layer and the first surface of the second pressure-sensitive or bonding adhesive layer.   
     
     
         19 . A repairing or reinforcement method comprising:
 providing the pressure-sensitive or bonding adhesive layer according to  claim 1 ;   applying the layer to an adherend; and   curing the layer such that the layer is bonded to the adherend.   
     
     
         20 . The repairing or reinforcement method according to  claim 19 , wherein
 the curing of the layer is accomplished by heat or by irradiation of ultraviolet light or electron beams.