1. Field of the Invention
The present invention generally relates to a film and, more particularly, to a near-infrared ray shielding film. The present invention also relates to a method of manufacturing the near-infrared ray shielding film and a composition for shielding near-infrared ray.
2. Description of the Related Art
Sunlight given off by the sun includes 5% of ultraviolet light, 43% of visible light and 52% of infrared light of the total electromagnetic radiation, respectively. Visible light-including sunlight is imported inside to meet the demands of lighting. However, the accompanied infrared light imported inside is the major reason of increasing indoor temperature.
For energy conservation and carbon reduction, a commercially available conventional near-infrared ray shielding film is provided. The conventional near-infrared ray shielding film with a decreased solar direct transmittance still poses a remained transmittance of visible lights, maintaining the indoor lighting and blocking infrared light being the major reason of increasing indoor temperature, thereby preventing indoor temperature from increasing. The methods of manufacturing the conventional near-infrared ray shielding film can be divided into the following:
In the first conventional method, the conventional near-infrared ray shielding film is obtained by binding to the surfaces of a transparent resin film via depositing metals or metal oxides. However, the requirement of deposition equipment with high vacuum quality and high precision raises the production cost of the conventional near-infrared ray shielding film and therefore, the conventional near-infrared ray shielding film are not in common use.
In the second conventional method, the conventional near-infrared ray shielding film is obtained via providing a paint including resins mixed with nanoparticles of metal oxides or hexaborides by wet coating method, followed by coating the paint onto the surfaces of a transparent resin film via slot extrusion, spray coating or soak coating. The paint and the transparent resin film belong to different materials and combination of the paint and the transparent resin film by coating may easily result in poor binding at the boundary between the paint and the transparent resin film. Therefore, the conventional near-infrared ray shielding film has a poor durability and the paint is easily peeled off from the transparent resin film.
In the third conventional method, the conventional near-infrared ray shielding film is directly shaping by a polyester mixture forming by dispersing microparticles of hexaborides, indium tin oxides or antimony tin oxides in polycarbonate resins or acrylic resins. Accordingly, the third conventional method shows decreased production cost and time. However, although the conventional near-infrared ray shielding film poses the transmittance of visible light of about 70%, the solar direct transmittance shows a high value merely about 50%.
In light of this, it is necessary to improve the conventional composition for shielding near-infrared ray, the conventional near-infrared ray shielding film and the conventional method of manufacturing the near-infrared ray shielding film.