# US 11,993,706 B2 · Polyester film and preparation method therefor

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- Number: US 11,993,706 B2
- Document ID: US11993706B2
- Status: Granted
- Kind: B2
- Application number: 17/422,683
- Filed: 2019-07-10
- Published: 2022-04-21
- Granted: 2024-05-28
- Earliest claimed: 2019-01-17
- Assignees: SK Chemicals Co., Ltd.
- Applicants: SK Chemicals Co., Ltd.
- Inventors: Yoo Jin Lee; Da-Young Hwang
- Web page: https://patentgrep.com/patent/US11993706B2

## CPC

- C08G 63/672: Dicarboxylic acids and dihydroxy compounds
- C08L 67/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds (C08L67/06 takes precedence)
- 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 48/21: the layers being joined at their surfaces
- B29C 55/04: uniaxial, e.g. oblique
- B29C 55/12: biaxial
- B29C 55/143: {firstly parallel to the direction of feed and then transversely thereto}
- B32B 27/08: of synthetic resin
- B32B 27/18: characterised by the use of special additives
- B32B 27/36: comprising polyesters
- B32B 37/15: with at least one layer being manufactured and immediately laminated before reaching its stable state, e.g. in which a layer is extruded and laminated while in semi-molten state
- C08G 63/183: Terephthalic acids
- C08J 5/18: Manufacture of films or sheets
- B29C 2948/92209: Temperature
- B29C 2948/92704: Temperature
- B29K 2067/003: {PET, i.e. poylethylene terephthalate}
- B29K 2105/0094: {having particular viscosity}
- B29K 2995/0012: having particular thermal properties
- B29K 2995/0053: bi-axially
- B32B 2250/03: 3 layers
- B32B 2250/244: All polymers belonging to those covered by group B32B27/36
- B32B 2250/40: Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA
- B32B 2270/00: Resin or rubber layer containing a blend of at least two different polymers
- B32B 2307/30: having particular thermal properties
- B32B 2307/306: Resistant to heat
- B32B 2307/518: bi-axially
- B32B 2307/54: Yield strength; Tensile strength
- B32B 2307/732: Dimensional properties
- B32B 2405/00: Adhesive articles, e.g. adhesive tapes
- B32B 2439/70: Food packaging
- B32B 2551/00: Optical elements
- B32B 2553/00: Packaging equipment or accessories not otherwise provided for
- 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)
- C08L 2203/16: used for films
- C08L 2203/30: used for thermoforming
- C08L 2205/025: containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- 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)
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- 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)
- 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

## Abstract

The present disclosure relates to a polyester film and a preparation method of the same. Since the polyester film includes a resin layer formed from a polyester resin including a first diol moiety derived from isosorbide and a second diol moiety derived from cyclohexanedimethanol in a controlled ratio on at least one surface of a base layer, it is possible to exhibit excellent heat resistance and adhesion.

## Claims

### Claim 1

A polyester film comprising: a base layer comprising a thermoplastic resin; and
a resin layer located on at least one surface of the base layer, and formed from a polyester resin that has a structure in which an acid moiety derived from a dicarboxylic acid or a derivative thereof and a diol moiety derived from a diol are repeated and is characterized in that a content of a first diol moiety (a) derived from isosorbide and a content of a second diol moiety (b) derived from cyclohexanedimethanol with respect to 100 mol % of a total diol moiety derived from the diol satisfy the following Equation 1,
wherein the polyester film is stretched in at least one of a longitudinal direction and a transverse direction, and
when a thickness of the polyester film is 200 μm, Tan delta calculated according to the following Equation 2 is 100° C. or more, and Strain at 100° C. calculated according to the following Equation 3 is 3% or less:
b
≤
18
⁢
⁢
mol
⁢
⁢
%
-
a
[
Equation
⁢
⁢
1
]
in the above Equation 1, a is a content (mol %) of a first diol moiety derived from isosorbide and is 4 to 18 mol % with respect to 100 mol % of a total diol moiety derived from the diol in the polyester resin, and b is a content (mol %) of a second diol moiety derived from cyclohexanedimethanol,
Tan
⁢
⁢
delta
=
E
′
/
E
″
[
Equation
⁢
⁢
2
]
in the above Equation 2, E′ and E″ are Young's modulus and loss modulus, respectively, measured using dynamic mechanical analysis under a fixed frequency and a temperature condition where the temperature increases at a rate of 3° C./min from room temperature up to 150° C.,
Strain
⁢
⁢
(
%
)
=
[
(
length
⁢
⁢
of
⁢
⁢
polyester
⁢
⁢
film
⁢
⁢
after
⁢
⁢
stress
⁢
⁢
application
⁢
⁢
at
⁢
⁢
100
⁢
°
⁢
⁢
C
.
-
length
⁢
⁢
of
⁢
⁢
polyester
⁢
⁢
film
⁢
⁢
before
⁢
⁢
stress
⁢
⁢
application
)
/
length
⁢
⁢
of
⁢
⁢
polyester
⁢
⁢
film
⁢
⁢
before
⁢
⁢
stress
⁢
⁢
application
]
⨯
100
[
Equation
⁢
⁢
3
]
in the above Equation 3, the length of polyester film after stress application and the length of polyester film before stress application are a length of the film deformed by a stress of 10 MPa applied at 100° C. under an isothermal condition for 10 minutes after increasing a temperature of the polyester film from room temperature according to a Creep TTS test and a length of the film before applying the stress, respectively.

### Claim 2 (depends on 1)

The polyester film of claim 1, wherein the dicarboxylic acid or the derivative thereof comprises terephthalic acid or a derivative thereof.

### Claim 3 (depends on 2)

The polyester film of claim 2, wherein the dicarboxylic acid or the derivative thereof comprises 60 mol % or less of a C8 to C14 aromatic dicarboxylic acid or a derivative thereof, or a C4 to C12 aliphatic dicarboxylic acid or a derivative thereof, as a dicarboxylic acid or a derivative thereof other than the terephthalic acid or the derivative thereof, with respect to 100 mol % of a total dicarboxylic acid or a derivative thereof.

### Claim 4 (depends on 1)

The polyester film of claim 1, wherein the diol moiety further comprises 82 to 96 mol % of a third diol moiety derived from a C2 to C12 aliphatic diol with respect to 100 mol % of the total diol moiety.

### Claim 5 (depends on 4)

The polyester film of claim 4, wherein the diol moiety consists of 4 to 18 mol % of the first diol moiety derived from isosorbide and 82 to 96 mol % of the third diol moiety derived from ethylene glycol as the aliphatic diol with respect to 100 mol % of the total diol moiety.

### Claim 6 (depends on 1)

The polyester film of claim 1, wherein the polyester resin further comprises at least one selected from the group consisting of 1 to 300 ppm of a polycondensation catalyst, 10 to 5000 ppm of a phosphorus stabilizer, 1 to 300 ppm of a cobalt-based coloring agent, 1 to 200 ppm of a crystallizing agent, 10 to 500 ppm of an antioxidant, and 10 to 300 ppm of a branching agent, based on a central metal atom.

### Claim 7 (depends on 1)

The polyester film of claim 1, wherein the polyester resin has an intrinsic viscosity of 0.50 to 1.00 dl/g as measured at 35° C. after being dissolved in ortho-chlorophenol at a concentration of 1.2 g/dl at 150° C. for 15 minutes.

### Claim 8 (depends on 1)

The polyester film of claim 1, wherein the resin layer is formed from a resin mixture further comprising polyethylene terephthalate together with the polyester resin, the resin mixture comprises the polyester resin and the polyethylene terephthalate in a weight ratio of 90:10 to 10:90, and the polyethylene terephthalate is different from the polyester resin.

### Claim 9 (depends on 8)

The polyester film of claim 8, wherein the polyethylene terephthalate has a melting point of 220 to 260° C.

### Claim 10 (depends on 1)

The polyester film of claim 1, wherein the resin layer further comprises 5 to 200 ppm of a crystallizing agent with respect to a total weight of the polyester resin.

### Claim 11 (depends on 1)

The polyester film of claim 1, wherein the thermoplastic resin is polyethylene terephthalate.

### Claim 12 (depends on 1)

The polyester film of claim 1, wherein the polyester film is a stretched film stretched in at least one of a longitudinal direction and a transverse direction at a total stretch ratio of 2 to 15 times.

### Claim 13 (depends on 1)

The polyester film of claim 1, wherein the polyester film is a stretched film that is biaxially stretched in a longitudinal direction at a stretch ratio of 2 to 5 times and in a transverse direction at a stretch ratio of 2 to 7 times.

### Claim 14 (depends on 1)

The polyester film of claim 1, wherein the polyester film comprises one or more of the base layers and resin layers, respectively.

### Claim 15 (depends on 1)

The polyester film of claim 1, wherein a ratio of a thickness of the resin layer with respect to 100% of a thickness of the base layer is 5 to 75%.

### Claim 16 (depends on 1)

The polyester film of claim 1, wherein the polyester film has a three-layer structure, and the resin layer is located on both upper and lower surfaces of the base layer.