Title:
ポリエステルフィルム
Document Type and Number:
Japanese Patent JP6597306
Kind Code:
B2
Abstract:
[Problem] To provide a cost efficient and lightweight polyester film which has excellent film forming properties, whiteness, reflectivity, and surface shape, and to inexpensively provide a surface light source that uses this polyester film so that the surface light source will not damage other members on contact and damage on the film is inconspicuous, thereby allowing the surface light source to have excellent brightness properties and brightness unevenness preventive performance. [Solution] A polyester film comprising at least two types of layers comprising a polyester layer (A) and a polyester layer (B). The polyester layer (A) forms a surface layer on at least one side of the polyester film. A coating layer (C) including particles is provided on one of the surface layers, and the particles included in the coating layer (C) are irregularly shaped porous particles which have a volume average particle size of 10 to 30 μm. Observations of an SEM cross-sectional photograph of protrusions created when coating the particles show that: the average value (Dh) of the distance (protrusion height) (dh) from the apex of a protrusion to the outermost surface of the polyester layer (A) is 10 to 30 μm; the average value (Dw) of the length (dw) of the part of a protrusion that contacts the polyester layer (A) (the width of the bottom of a protrusion) is 10 to 35 μm; the ratio of Dh and Dw (Dh/Dw) is 0.70 to 1.00; the average value (Dv) of the particle length (dv) of particles in a direction parallel to the layer (A) at a height of dh/2 from the outermost surface of the polyester layer (A) (width of the center of a protrusion) is 10 to 35 μm; the ratio of Dh and Dv (Dh/Dv) is 0.90 to 1.00; the ratio of Dv and Dw (Dv/Dw) is 0.80 to 1.05; and the number of particles per 1 mm2 of the film surface is 1000 to 2000.
Inventors:
Masatoshi Izawa
Masahiro Hasegawa
Masahiro Hasegawa
Application Number:
JP2015537856A
Publication Date:
October 30, 2019
Filing Date:
July 14, 2015
Export Citation:
Assignee:
TORAY INDUSTRIES,INC.
International Classes:
B32B27/36; B32B27/20; C08J7/043; C08J7/046; G02B5/02; G02B5/08
Domestic Patent References:
| JP2011075779A | ||||
| JP2000075134A | ||||
| JP2010211010A | ||||
| JP2010211027A | ||||
| JP2006328173A |
Foreign References:
| WO2010029910A1 |