# US 12,760,167 B2 · Biaxially oriented polyester film and production method therefor

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- Number: US 12,760,167 B2
- Document ID: US12760167B2
- Status: Granted
- Kind: B2
- Application number: 18/558,588
- Filed: 2022-05-27
- Published: 2024-07-04
- Granted: 2026-10-13
- Earliest claimed: 2021-06-02
- Assignees: Toyobo Co., Ltd.
- Applicants: Toyobo Co., Ltd.
- Inventors: Nobuyuki Manabe; Takamichi Goto; Masayuki Haruta
- Web page: https://patentgrep.com/patent/US12760167B2

## CPC

- C08J 11/12: by dry-heat treatment only
- B29C 48/0018: {combined with shaping by orienting, stretching or shrinking, e.g. film blowing (B29C48/0017 takes precedence)}
- B29C 48/08: flexible, e.g. films
- B29C 48/305: having a wide opening, e.g. for forming sheets
- B29C 48/914: {Cooling drums}
- B29C 55/12: biaxial
- B29C 55/14: successively
- B29C 71/02: Thermal after-treatment {(B29C71/0063 and B29C71/0072 take precedence)}
- B29D 7/01: Films or sheets
- C08J 5/18: Manufacture of films or sheets
- C08L 67/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds (C08L67/06 takes precedence)
- B29C 48/49: using two or more extruders to feed one die or nozzle
- B29C 2071/022: {Annealing}
- B29C 2071/025: {Quenching, i.e. rapid cooling of an object}
- B29K 2067/00: Use of polyesters {or derivatives thereof}, as moulding material
- B29L 2007/00: Flat articles, e.g. films or sheets (B29L2024/00 takes precedence)
- C08J 2333/04: esters
- C08J 2367/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds; (C08J2367/06 takes precedence)
- C08J 2467/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds (C08J2467/06 takes precedence)
- Y02W 30/62: Plastics recycling; Rubber recycling
- C08K 3/36: Silica
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## Abstract

The invention provides a biaxially oriented polyester film that is formed of a polyester resin composition containing polyester resin employing recycled PET bottles and particles, and meets all of requirements (1) to (4): (1) crystallization temperature is 120-139° C., (2) amount of change in orientation angle with respect to the film transverse direction is 0-10° per 0.5 m, (3) heat shrinkage rate at 150° C. for 30 minutes is 0.5-2.0% in the machine direction and −1.0-1.0% in the transverse direction, and (4) content rate of an isophthalic acid component with respect to 100 mol % of total dicarboxylic acid components in the polyester resin composition is 0.01-3.0 mol %. Maximum and minimum values of data for each measurement position are within the range in the requirement (3), and a maximum value of each amount of change between two adjacent sample collection positions is within the range in the requirement (2).

## Claims

### Claim 1

A biaxially oriented polyester film comprising a polyester resin composition containing polyester resin employing recycled PET bottles and particles,
wherein the biaxially oriented polyester film meets all of requirements (1) to (4) below:
(1) a crystallization temperature when heated that is measured using a differential scanning calorimeter is 120° C. or more and 139° C. or less;
(2) an amount of change in orientation angle with respect to a film transverse direction is 0° or more and 10° or less per 0.5 m;
(3) a heat shrinkage rate when heat treatment at 150° C. for 30 minutes is performed over an entire width of the film is in a range of 0.5% or more and 2.0% or less in a machine direction and in a range of −1.0% or more and 1.0% or less in a transverse direction; and
(4) a content rate of an isophthalic acid component with respect to 100 mol % of total dicarboxylic acid components in the polyester resin composition is 0.01 mol % or more and 3.0 mol % or less,
where sample collection positions in the requirements (2) and (3) are a center position with respect to the entire width and positions at intervals of 500 mm from the center position toward both ends, and are end positions where collection is possible in a case where intervals of 500 mm cannot be secured near both ends, and
it is required that maximum and minimum values of data for each measurement position is within the range in the requirement (3) and a maximum value of each amount of change between two adjacent sample collection positions is within the range in the requirement (2).

### Claim 2 (depends on 1)

The biaxially oriented polyester film according to claim 1, wherein a content rate of the polyester resin employing recycled PET bottles in the polyester resin composition making up the biaxially oriented polyester film is 50 mass % or more and 100 mass % or less.

### Claim 3 (depends on 1)

The biaxially oriented polyester film according to claim 1, wherein the polyester resin employing recycled PET bottles is mechanically recycled polyester resin and/or chemically recycled polyester resin.

### Claim 4 (depends on 1)

A production method for the biaxially oriented polyester film according to claim 1, the method comprising a polyester raw resin melt extrusion step, a biaxial stretching step, a heat setting treatment step, a thermal relaxation treatment step, and a step of winding a biaxially oriented polyester film into a roll, wherein stretching in a machine direction is performed, then stretching in a transverse direction is performed in a tenter, and a cooling region is provided before a heat setting treatment region in the biaxial stretching step.