Transparent polyester film with low visible light transmittance and high infrared-blocking rate

Abstract

A transparent polyester film has low visible light transmittance of 5-50% by JIS K7705 testing standard and a high infrared-blocking rate of at least 90% by JIS R3106 testing standard, which is extruded from a kind of polyester resins obtained from 5-40 wt % of nanoparticle-based thermal insulation slurry and/or 0.005-0.1 wt % of nanoparticle-based black pigment slurry by weight of and to react with the polymerization materials to completely perform an esterification and a polycondensation, wherein the thermal insulation nanoparticle has a chemical formula of CsXNYWO3-ZClC with an average particle size of 10-90 nm and the nanoparticle-based black contains carbon black particles having a particle size of 20-80 nm.

What is claimed is: 
     
         1 . A transparent polyester film comprising a low visible light transmittance of 5-50% according to the JIS K7705 testing standard, a high infrared-blocking rate of at least 90% according to the JIS R3106 testing standard, and a haze level lower than 1.5% according to the JIS K7705 testing standard. 
     
     
         2 . The transparent polyester film according to  claim 1 , wherein the transparent polyester film is a polyethylene terephthalate (PET) film, a polyethylene naphthalate (PEN) film, a polyvinyl chloride (PVC) film, a polycarbonate (PC) film, a polypropylene (PP) film, a polyethylene (PE) film or a nylon film. 
     
     
         3 . The transparent polyester film according to  claim 1 , wherein the film thickness is from 12 to 75 μm. 
     
     
         4 . The transparent polyester film according to  claim 1 , wherein the polyester film is obtained by a polyester resin including a thermal insulation slurry 5-40wt % and a black pigment slurry 0.005-0.1wt %. 
     
     
         5 . The transparent polyester film according to  claim 4 , wherein the thermal insulation slurry includes an nanoparticle-based thermal insulation slurry, powdered tungsten-containing composite metal oxychloride having a chemical formula of Cs X N Y WO 3-z CL C , wherein Cs is cesium; N is tin (Sn), antimony (Sb) or bismuth (Bi); W is tungsten; O is oxygen; and X, Y, Z, and C are positive numbers satisfying the following conditions:
 X≤1.0; Y≤1.0; Y/X≤1.0; Z≤0.6, and C≤0.1.   
     
     
         6 . The transparent polyester film according to  claim 5 , further comprising an ethylene glycol 30-70 wt % and a dispersing aid 5-40wt %. 
     
     
         7 . The transparent polyester film according to  claim 4 , wherein the black pigment slurry includes a carbon black particles with an average particle size of 20-80 nm 
     
     
         8 . The transparent polyester film according to  claim 4 , wherein the black pigment slurry includes includes a carbon black particles 5-25 wt %, an ethylene glycol 40-75 wt % and a dispersing aid at 10-50 wt %.