Biaxially oriented polyester film and method for producing same
AssigneeToyobo Co., Ltd.
InventorsMahiro NAKANO, Masayuki HARUTA
Life of this patent
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Abstract
The present invention is to provide a method for producing a biaxially oriented polyester film that is superior in mechanical properties, transparency, and heat resistance, and at the same time, superior in secondary processing suitability and printing appearance. Disclosed is a biaxially oriented polyester film, having at least one surface satisfying the following requirements (1) and (2), and the film satisfying the following requirements (3) and (4). (1) A maximum peak height roughness (SRp) is 1.2 μm to 1.6 μm. (2) An arithmetic average roughness (SRa) is 0.024 μm to 0.045 μm. (3) A tensile strength in a longitudinal direction and a width direction is 180 MPa to 300 MPa. (4) A haze is 7% or less.
Claims20
A biaxially oriented polyester film, having at least one surface satisfying the following requirements (1) and (2), and the film satisfying the following requirements (3) and (4).
- (1) A maximum peak height roughness (SRp) is 1.2 μm to 1.6 μm.
- (2) An arithmetic average roughness (SRa) is 0.024 μm to 0.045 μm.
- (3) A tensile strength in a longitudinal direction and a width direction is 180 MPa to 300 MPa.
- (4) A haze is 7% or less.
A method for producing a biaxially oriented polyester film, comprising:
- mixing a polyethylene terephthalate-based resin containing 7000 ppm by mass or more and 22000 ppm by mass or less of first inorganic particles and a polyethylene terephthalate-based resin containing 0 to 50 ppm by mass of second inorganic particles to obtain a polyester resin composition containing 500 to 1500 ppm by mass of inorganic particles;
- melt extruding the polyester resin composition to obtain an unstretched sheet;
- biaxially stretching the unstretched sheet to obtain a biaxially stretched film;
- and
- heat setting the biaxially stretched film at a temperature of 200° C. or higher and 250° C. or lower, followed by relaxing the biaxially stretched film by 2% to 10% in a width direction while reducing the temperature to 200° C. or lower.
A method for producing a biaxially oriented polyester film, comprising:
- mixing a polyethylene terephthalate-based resin containing 7000 ppm by mass or more and 22000 ppm by mass or less of first inorganic particles and a polyethylene terephthalate-based resin containing 0 to 50 ppm by mass of second inorganic particles to obtain a first polyester resin composition containing 500 to 1500 ppm by mass of inorganic particles;
- melting the first polyester resin composition and a second polyester resin composition separately;
- extruding the first polyester resin composition and the second polyester resin composition through a die to obtain an unstretched sheet having a layer structure of a layer consisting of the first polyester resin composition/a layer consisting of the second polyester resin composition;
- biaxially stretching the unstretched sheet to obtain a biaxially stretched film;
- and
- heat setting the biaxially stretched film at a temperature of 200° C. or higher and 250° C. or lower, followed by relaxing the biaxially stretched film by 2% to 10% in a width direction while reducing the temperature to 200° C. or lower.
A method for producing a biaxially oriented polyester film, comprising:
- mixing a polyethylene terephthalate-based resin containing 7000 ppm by mass or more and 22000 ppm by mass or less of first inorganic particles and a polyethylene terephthalate-based resin containing 0 to 50 ppm by mass of second inorganic particles to obtain a first polyester resin composition containing 500 to 1500 ppm by mass of inorganic particles;
- melting the first polyester resin composition and a second polyester resin composition separately;
- co-extruding the first polyester resin composition and the second polyester resin composition through a die to obtain an unstretched sheet having a layer structure of a layer consisting of the first polyester resin composition/a layer consisting of the second polyester resin composition/a layer consisting of the first polyester resin composition;
- biaxially stretching the unstretched sheet to obtain a biaxially stretched film;
- and
- heat setting the biaxially stretched film at a temperature of 200° C. or higher and 250° C. or lower, followed by relaxing the biaxially stretched film by 2% to 10% in a width direction while reducing the temperature to 200° C. or lower.
A method for producing a biaxially oriented polyester film, comprising:
- mixing a polyethylene terephthalate-based resin containing 7000 ppm by mass or more and 22000 ppm by mass or less of first inorganic particles and a polyethylene terephthalate-based resin containing 0 to 50 ppm by mass of second inorganic particles to obtain a first polyester resin composition containing 500 to 1500 ppm by mass of inorganic particles;
- melting the first polyester resin composition, a second polyester resin composition, and a third polyester resin composition separately;
- co-extruding the first polyester resin composition, the second polyester resin composition, and the third polyester resin composition through a die to obtain an unstretched sheet having a layer structure of a layer consisting of the first polyester resin composition/a layer consisting of the second polyester resin composition/a layer consisting of the third polyester resin composition;
- biaxially stretching the unstretched sheet to obtain a biaxially stretched film;
- and
- heat setting the biaxially stretched film at a temperature of 200° C. or higher and 250° C. or lower, followed by relaxing the biaxially stretched film by 2% to 10% in a width direction while reducing the temperature to 200° C. or lower.
Dependencies are inferred from the claim text.