Void-containing heat-shrinkable polyester film
AssigneeToyobo Co., Ltd.
InventorsMasayuki HARUTA, Norimi TABOTA
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Abstract
The present invention provides a void-containing heat-shrinkable polyester film which has satisfactory shrinkage finishing properties and printability even if productivity is improved. The void-containing heat-shrinkable polyester film is a multilayer structure having a non-foamed layer on both outer sides of the foamed layer, and by controlling the film thickness, density, and number of moles of the amorphous component on both outer sides, specific heat shrinkage characteristics and gloss can be improved.
Claims16
A void-containing heat-shrinkable polyester film comprising a structure having three or more layers including at least one polyester resin layer containing voids and at least two layers sandwiching the void-containing layer,
- wherein the void-containing heat-shrinkable polyester film satisfies the following requirements (1) to (7):
- (1) heat shrinkage in a main shrinkage direction is 30% or more and 85% or less when being treated in hot water at a treatment temperature of 90° C. for a treatment time of 10 seconds;
- (2) gloss on both sides of the film measured at an angle of 60 degrees is 40% or more and 150% or less;
- (3) a thickness difference between both outermost layers of the film is 2μm or less;
- (4) thicknesses of both outermost layers of the film are 3 μm or more and 12 μm or less;
- (5) a density difference between both outermost layers of the film is 0.005 g/cm3 or less;
- (6) a difference in the number of moles of an amorphous component between both outermost layers of the film is 1 mol % or less;
- and
- (7) light transmittance is 40% or less.
Dependencies are inferred from the claim text.