# US 11,299,624 B2 · Thermoplastic polyurethane film and preparation method thereof

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- Number: US 11,299,624 B2
- Document ID: US11299624B2
- Status: Granted
- Kind: B2
- Application number: 16/494,558
- Filed: 2018-03-27
- Published: 2020-01-09
- Granted: 2022-04-12
- Earliest claimed: 2017-03-27
- Assignees: LG Chem, Ltd.
- Applicants: LG Chem, Ltd.
- Inventors: Sang Yool Lee; Joo Hee Hong; Se Jung Park; Sang Hwan Kim; Jang Soon Kim
- Web page: https://patentgrep.com/patent/US11299624B2

## CPC

- C08J 7/0427: {with only one layer of a composition containing a polymer binder (with more layers C08J7/042)}
- C08L 75/04: Polyurethanes
- C08J 5/18: Manufacture of films or sheets
- C09D 175/04: Polyurethanes
- C08J 2367/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds; (C08J2367/06 takes precedence)
- C08J 2375/04: Polyurethanes
- C08J 2475/04: Polyurethanes
- C08K 5/0025: {Crosslinking or vulcanising agents; including accelerators}
- C08K 5/21: Urea; Derivatives thereof, e.g. biuret
- 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)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## Abstract

A thermoplastic polyurethane film including a cured product of a polyurethane resin composition is provided. The polyurethane resin composition includes a polyurethane resin, a first isocyanate-based curing agent, and an organic solvent. The thermoplastic polyurethane film has a tensile strength break of 50 MPa to 80 MPa. A method for preparing the thermoplastic polyurethane film is also provided.

## Claims

### Claim 1

A thermoplastic polyurethane film comprising:
a cured product of a polyurethane resin composition, wherein the polyurethane resin compositon comprises
a polyurethane resin,
a first isocyanate-based curing agent, and
an organic solvent,
wherein the thermoplastic polyurethane film has a tensile strength at break of 50 MPa to 80 MPa,
wherein a content of the first isocyanate-based curing agent is 7.5 parts by weight to 15 parts by weight based on 100 parts by weight of the polyurethane resin.

### Claim 2 (depends on 1)

The thermoplastic polyurethane film of claim 1, wherein the first isocyanate-based curing agent comprises two to six isocyanate functional groups.

### Claim 3 (depends on 1)

The thermoplastic polyurethane film of claim 1, wherein the polyurethane resin is a copolymer of a mixture comprising:
a polyol having a number average molecular weight of 1,800 g/mol to 2,200 g/mol;
a chain extender comprising a diol having 4 to 10 carbon atoms; and
a second isocyanate-based curing agent.

### Claim 4 (depends on 3)

The thermoplastic polyurethane film of claim 3, wherein a content of the polyol is 50 wt % to 75 wt % based on a weight of the mixture.

### Claim 5 (depends on 3)

The thermoplastic polyurethane film of claim 3, wherein a content of the chain extender is 5 wt % to 15 wt % based on a weight of the mixture.

### Claim 6 (depends on 3)

The thermoplastic polyurethane film of claim 3, wherein a content of the second isocyanate-based curing agent is 20 wt % to 37.5 wt % based on a weight of the mixture.

### Claim 7 (depends on 1)

The thermoplastic polyurethane film of claim 1, wherein a content of a solid content of the polyurethane resin composition is 20% to 70%.

### Claim 8 (depends on 1)

The thermoplastic polyurethane film of claim 1, wherein the thermoplastic polyurethane film has a thickness of 10 μm to 250 μm.

### Claim 9 (depends on 1)

A method for preparing the thermoplastic polyurethane film according to claim 1, comprising:
preparing a polyurethane resin composition comprising a polyurethane resin, a first isocyanate-based curing agent, and an organic solvent;
forming a polyurethane resin layer by applying the polyurethane resin composition onto a substrate film and heat-treating the polyurethane resin composition; and
additionally curing the polyurethane resin layer.

### Claim 10 (depends on 9)

The method of claim 9, wherein the heat-treating is carried out at a temperature of 100° C. to 150° C.

### Claim 11 (depends on 9)

The method of claim 9, wherein the additional curing is carried out at a temperature of 40° C. to 80° C. for 12 hours to 48 hours.

### Claim 12 (depends on 9)

The method of claim 9, wherein the polyurethane resin is prepared by carrying out a copolymerization reaction of a mixture, wherein the mixture comprises:
a polyol having a number average molecular weight of 1,800 g/mol to 2,200 g/mol;
a chain extender comprising a diol having 4 to 10 carbon atoms; and
a second isocyanate-based curing agent, in an organic solvent.

### Claim 13 (depends on 12)

The method of claim 12, wherein the copolymerization reaction is carried out at a temperature of 50° C. to 70° C.