Interlayer film for laminated glass and laminated glass

Abstract

The invention provides an interlayer film for a laminated glass and a laminated glass, which are protected against a slump in TL value through attenuation of said coincidence effect and adapted to display an outstanding sound insulation performance over a broad temperature range. An interlayer film for a laminated glass comprising a plasticizer and a polyacetal resin, which is a blend of a polyacetal resin having an average polymerization degree of 1,000 to 3,000 and a polyacetal resin having an average polymerization degree of 3,000 to 5,000, and which has an acetalization degree of 60 to 85 mol % and an acetyl group content of 8 to 30 mol %. An interlayer film for a laminated glass which shows a temperature dependence of loss tangent in which the lowest-temperature side maximum of loss tangent appears at 30° C. or lower when examined for dynamic viscoelasticity.

1 . An interlayer film for a laminated glass comprising a poly(vinyl acetal) resin (C), 
 which is a blend of a poly(vinyl acetal) resin (A) and a poly(vinyl acetal) resin (B), and a plasticizer,    said poly(vinyl acetal) resin (A) having an average polymerization degree of 1,000 to 3,000,    said poly(vinyl acetal) resin (B) having an average polymerization degree of 3,000 to 5,000,    the difference in the average polymerization degree between said poly (vinyl acetal) resin (A) and poly (vinyl acetal) resin (B) being not less than 1,500,    said poly (vinyl acetal) resin (C) having an acetalization degree of 60 to 85 mol % and an acetyl group content of 8 to 30 mol %, with the combined total of said acetalization degree and acetyl group content being not less than 75 mol %, and    the cloud point of a solution prepared by dissolving 8 weight parts of said poly(vinyl acetal) resin (C) in 100 weight parts of said plasticizer being not higher than 50° C.    
     
     
         2 . An interlayer film for a laminated glass 
 which comprises a laminate of films each comprising a poly (vinyl acetal) resin and at least one plasticizer selected from the group consisting of triethylene glycol di-2-ethylhexanoate, tetraethylene glycol di-2-ethylhexanoate, triethylene glycol di-n-heptanoate, and tetraethylene glycol di-n-heptanoate, and    which shows a temperature dependence of loss tangent in which the lowest-temperature side maximum of loss tangent appears at 30° C. or lower when examined for dynamic viscoelasticity.    
     
     
         3 . The interlayer film for a laminated glass according to  claim 2 , 
 wherein at least one constituent layer is such that the cloud point of a solution prepared by dissolving 8 weight parts of the poly(vinyl acetal) resin in 100 weight parts of the plasticizer is not higher than 50° C.    
     
     
         4 . The interlayer film for a laminated glass according to  claim 2  or  3 , 
 wherein the amount of the plasticizer relative to 100 weight parts of the poly(vinyl acetal) resin is larger in at least one constituent layer than that in the other layer or layers by not less than 5 weight parts.    
     
     
         5 . The interlayer film for a laminated glass according to any of  claims 2  to  4 , 
 wherein at least one constituent layer is such that the poly(vinyl acetal) resin has an average polymerization degree of not less than 1,500, an acetalization degree of 60 to 85 mol % and an acetyl group content of 8 to 30 mol %, with the combined total of said acetalization degree and acetyl group content being not less than 75 mol %.    
     
     
         6 . The interlayer film for a laminated glass according to any of  claims 2  to  5 , 
 in which at least one constituent layer comprises a poly(vinyl acetal) resin (C) derived from a poly (vinyl alcohol) resin    which is a blend of a poly(vinyl alcohol) resin (A) and a poly(vinyl alcohol) resin (B), and a plasticizer,    the difference in the average polymerization degree between said poly(vinyl alcohol) resin (A) and poly(vinyl alcohol) resin (B) being not less than 500, and    said poly(vinyl acetal) resin (C) having an acetalization degree of 60 to 85 mol % and an acetyl group content of 8 to 30 mol %, with the combined total of said acetalization degree and acetyl group content being not less than 75 mol %.    
     
     
         7 . The interlayer film for a laminated glass according to any of  claims 2  to  5 , 
 in which at least one constituent layer comprises a poly(vinyl acetal) resin (F),    which is a blend of a poly(vinyl acetal) resin (D) and a poly(vinyl acetal) resin (E), and a plasticizer,    the difference in the average polymerization degree between said poly(vinyl acetal) resin (D) and poly(vinyl acetal) resin (E) being not less than 500, and    said poly (vinyl acetal) resin (F) having an acetalization degree of 60 to 85 mol % and an acetyl group content of 8 to 30 mol %, with the combined total of said acetalization degree and acetyl group content being not less than 75 mol %.    
     
     
         8 . The interlayer film for a laminated glass according to  claim 6 , 
 wherein the poly(vinyl alcohol) resin (A) has an average polymerization degree of 500 to 3,000 and the poly (vinyl alcohol) resin (B) has an average polymerization degree of 3,000 to 5,000.    
     
     
         9 . The interlayer film for a laminated glass according to  claim 7 , 
 wherein the poly(vinyl acetal) resin (D) has an average polymerization degree of 500 to 3,000 and the poly (vinyl acetal) resin (E) has an average polymerization degree of 3,000 to 5,000.    
     
     
         10 . The interlayer film for a laminated glass according to any of  claims 2  to  9 , 
 wherein at least one constituent layer is such that the poly(vinyl acetal) resin contains a metal oxide microparticle having a heat ray-shielding function.    
     
     
         11 . The interlayer film for a laminated glass according to any of  claims 1  to  10 , 
 which is further laminated with a polyester film.    
     
     
         12 . The interlayer film for a laminated glass according to any of  claims 1  to  11 , 
 wherein the poly(vinyl acetal) resin is a poly(vinyl butyral) resin.    
     
     
         13 . A laminated glass comprising an integral artifact consisting of at least a pair of glass panels and, as interposed therebetween, an interlayer film for a laminated glass according to any of  claims 1  to  12 .