Solar-radiation-shielding material for vehicle window and window for vehicle

Abstract

A solar-radiation-shielding material for vehicle windows reduces the visible light transmittance, and reduces the value of solar radiation transmittance/visible light transmittance. The visible light transmittance of the solar-radiation-shielding material is in the range of 5%. The transmission color of the solar-radiation-shielding material satisfies the Expression 2: −14<a*<2, and −8<<2.

1 . A solar-radiation-shielding material for vehicle windows, the material comprising fine particles having a heat-ray-shielding function used in a window of a vehicle, wherein
 the fine particles having the heat-ray-shielding function are a mixture including
 at least one type of fine particles selected from the group consisting of lanthanum hexaboride, titanium nitride, and tungsten oxide and 
 at least one type of fine particles selected from the group consisting of antimony-doped tin oxide, tin-doped indium oxide, and a composite tungsten oxide defined by a general formula: M Y WO Z  (0.001≦Y≦1.0, and 2.2≦Z≦3.0); 
   the visible light transmittance of the solar-radiation-shielding material is in the range of 5% or more and 40% or less;   the solar radiation transmittance and the visible light transmittance of the solar-radiation-shielding material satisfy the following Expression 1; and   the transmission color of the solar-radiation-shielding material satisfies the following Expression 2:
   solar radiation transmittance/visible light transmittance<1, and  Expression 1 
   −14<a*<2, and −8<b*<2.  Expression 2 
   
     
     
         2 . A solar-radiation-shielding material for vehicle windows, the material comprising fine particles having a heat-ray-shielding function used in a window of a vehicle, wherein
 the fine particles having the heat-ray-shielding function are a mixture including
 at least one type of fine particles selected from the group consisting of lanthanum hexaboride, titanium nitride, and tungsten oxide, 
 at least one type of fine particles selected from the group consisting of antimony-doped tin oxide, tin-doped indium oxide, and a composite tungsten oxide defined by a general formula: M Y WO Z  (0.001≦Y≦1.0, and 2.2≦Z≦3.0), and iron oxide fine particles; 
   the visible light transmittance of the solar-radiation-shielding material is in the range of 5% or more and 40% or less;   the solar radiation transmittance and the visible light transmittance of the solar-radiation-shielding material satisfy the following Expression 3; and   the transmission color of the solar-radiation-shielding material satisfies the following Expression 4:
   solar radiation transmittance/visible light transmittance<1, and  Expression 3 
   −2<a*<14, and 2<b*<12.  Expression 4 
   
     
     
         3 . The solar-radiation-shielding material for vehicle windows according to  claim 2 , wherein the tungsten oxide is WO 2  or W 18 O 49 . 
     
     
         4 . The solar-radiation-shielding material for vehicle windows according to  claim 2 , wherein the element M contained in the composite tungsten oxide fine particle is at least one selected from the group consisting of Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn. 
     
     
         5 . The solar-radiation-shielding material for vehicle windows according to  claim 4 , wherein the fine particles having the heat-ray-shielding function have a diameter of 300 nm or less. 
     
     
         6 . The solar-radiation-shielding material for vehicle windows according to  claim 5 , wherein the fine particles having the heat-ray-shielding function are surface-treated with at least one type of compound selected from the group consisting of a silane compound, a titanium compound, and a zirconia compound. 
     
     
         7 . The solar-radiation-shielding material for vehicle windows according to  claim 6 , the solar-radiation-shielding material further comprising at least one type of fine particles selected from the group consisting of zinc oxide fine particles, cerium oxide fine particles, and titanium oxide fine particles. 
     
     
         8 . The solar-radiation-shielding material for vehicle windows according to  claim 7 , wherein the fine particles having the heat-ray-shielding function are contained in a polycarbonate resin molded product. 
     
     
         9 . The solar-radiation-shielding material for vehicle windows according to  claim 8 , wherein the polycarbonate resin molded product is provided with an abrasion-resistant hard coat layer on at least one surface. 
     
     
         10 . The solar-radiation-shielding material for vehicle windows according to  claim 9 , the solar-radiation-shielding material further comprising another resin molded product being laminated. 
     
     
         11 . The solar-radiation-shielding material for vehicle windows according to  claim 7 , wherein the fine particles having the heat-ray-shielding function are contained in one type of resin selected from the group consisting of a polyvinyl butyral resin, a polyvinyl acetate resin, and a polyvinyl alcohol resin. 
     
     
         12 . A solar-radiation-shielding material for vehicle windows having a laminated structure comprising the solar-radiation-shielding material according to  claim 11  interposed as an intermediate film between two laminated plates, wherein the laminated plates are at least one selected from the group consisting of an inorganic glass plate, a polycarbonate resin molded product, and a polyethylene terephthalate resin molded product. 
     
     
         13 . The solar-radiation-shielding material for vehicle windows according to  claim 12 , wherein at least one of the laminated plates is formed from the solar-radiation-shielding material according. 
     
     
         14 . The solar-radiation-shielding material for vehicle windows according to  claim 13 , the material having a shape of a thickness of from 2.5 to 30 mm and a maximum projected area of from 400 to 60000 cm 2 . 
     
     
         15 . A window of a vehicle, the window comprising a solar-radiation-shielding material for vehicle windows according to  claim 1 .