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US 8,999,499 B2Granted
White porous polyester film and preparation method thereof
AssigneeSkc Co., Ltd.
InventorsHeon Jung Shin, Jae Seog Ju, Min Ju Kim
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Abstract
A white porous polyester film of the present invention comprising a polyester-based monopolymer/copolymer blend, a crystalline polymer resin which is not miscible with a polyester and has a heat deformation temperature of 90° C. or higher, inorganic particles, a whitening agent, and a stabilizing agent has improved optical properties, and thus is useful as a film for use in printing, labeling, electronics, and display applications.
Claims9
A white porous polyester film comprising
- a blend of a polyester-based monopolymer and a polyester-based copolymer;
- a crystalline polymer resin which is not miscible with a polyester and has a heat deformation temperature of 90° C. or higher, wherein the crystalline polymer consists of a syndiotactic polystyrene;
- inorganic particles;
- a whitening agent;
- and
- a stabilizing agent,
- wherein the amounts of the crystalline polymer resin and the inorganic particles are in the range of 4 to 15 wt % and 15 to 30 wt %, respectively, based on the total weight of the film;
- wherein the sum of the amounts of the syndiotactic polystyrene and the inorganic particles is in the range of 19 to 45 wt % based on the total weight of the film;
- wherein the blend is obtained by blending:
- (a) a polyester-based monopolymer resin selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, and a mixture thereof;
- and (b) a polyester-based copolymer resin prepared from isophthalic acid, dimethyl isophthalate, or cyclohexane dimethanol as a monomer, wherein the weight ratio of (a) the polyester-based monopolymer and (b) the polyester-based copolymer is in the range of 8:2 to 2:8;
- wherein the inorganic particles are selected from the group consisting of particles of barium sulfate, titanium dioxide, calcium carbonate, silica, kaoline, talc, zeolite, and a mixture thereof, each having an average particle diameter of 0.1 to 0.7 μm;
- and
- wherein the film comprises a first population of voids having an average diameter ranging from 1 to 5 μm in the interface between the inorganic particles and the polyester resin and a second population of voids having an average diameter ranging from 10 to 20 μm in the interface between the crystalline polymer resin and the polyester resin.
11 more elements
A method for preparing a white porous polyester film comprising:
- (i) mixing a blend of polyester-based monopolymer and a polyester-based copolymer, a crystalline polymer resin which is not miscible with a polyester and has a heat deformation temperature of 90° C. or higher, inorganic particles, a whitening agent, and a stabilizing agent such that the sum of the amounts of the crystalline polymer resin and the inorganic particles is in the range of 19 to 45 wt % based on the total weight of the film,
- wherein the amounts of the crystalline polymer resin and the inorganic particles are in the range of 4 to 15 wt % and 15 to 30 wt %, respectively, based on the total weight of the film;
- (ii) melt-extruding the blended resin to obtain a film sheet;
- and
- (iii) biaxially drawing the sheet in the longitudinal and transverse directions,
- wherein the crystalline polymer consists of a syndiotactic polystyrene;
- wherein the blend is obtained by mixing (a) a polyester-based monopolymer resin selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, and a mixture thereof;
- and (b) a polyester-based copolymer resin prepared from isophthalic acid, dimethyl isophthalate, or cyclohexane dimethanol as a monomer, wherein the weight ratio of (a) the polyester-based monopolymer and (b) the polyester-based copolymer is in the range of 8:2 to 2:8;
- wherein the inorganic particles are selected from the group consisting of particles of barium sulfate, titanium dioxide, calcium carbonate, silica, kaoline, talc, zeolite, and a mixture thereof, each having an average particle diameter of 0.1 to 0.7 μm;
- wherein the film comprises two populations of voids having respective average diameters ranging from 1 to 5 μm and from 10 to 20 μm;
- and
- wherein the film comprises a first population of voids having an average diameter ranging from 1 to 5 μm in the interface between the inorganic particles and the polyester resin and a second population of voids having an average diameter ranging from 10 to 20 μm in the interface between the crystalline polymer resin and the polyester resin.
9 more elements
Dependencies are inferred from the claim text.