# US 11,027,523 B2 · Polyester film incorporating silicone for release of canned meat products

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- Number: US 11,027,523 B2
- Document ID: US11027523B2
- Status: Granted
- Kind: B2
- Application number: 15/663,142
- Filed: 2017-07-28
- Published: 2017-11-16
- Granted: 2021-06-08
- Earliest claimed: 2015-11-30
- Assignees: Toray Plastics (America), Inc.
- Applicants: Toray Plastics (America), Inc.
- Inventors: Jan Moritz; Pat Andrews; Keunsuk P. Chang; Christopher Nothnagle; Stefanos Sakellarides
- Web page: https://patentgrep.com/patent/US11027523B2

## CPC

- B32B 15/09: comprising polyesters
- B32B 1/00: Layered products having a non-planar shape
- B32B 7/04: Interconnection of layers
- B32B 7/12: using interposed adhesives or interposed materials with bonding properties
- B32B 15/18: comprising iron or steel {(B32B15/011, B32B15/012 and B32B15/013 take precedence)}
- B32B 15/20: comprising aluminium or copper {(B32B15/016 and B32B15/017 take precedence)}
- B32B 27/08: of synthetic resin
- B32B 27/18: characterised by the use of special additives
- B32B 27/283: {comprising polysiloxanes}
- B32B 27/36: comprising polyesters
- B65D 25/14: Linings or internal coatings (of containers made by folding or erecting blanks made of paper B65D5/56 {; linings for domestic water storage heaters F24H1/183})
- B65D 81/24: Adaptations for preventing deterioration or decay of contents; Applications to the container or packaging material of food preservatives, fungicides, pesticides or animal repellants (with thermal insulation B65D81/38)
- B65D 81/3415: {specially adapted to be heated in hot water, e.g. boil pouches (dissolvable packages B65D65/46; packaging articles or materials intended to be mixed or infused with a liquid B65D85/808)}
- C08J 5/18: Manufacture of films or sheets
- C08L 67/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds (C08L67/06 takes precedence)
- B32B 2250/02: 2 layers
- B32B 2250/03: 3 layers
- B32B 2250/04: 4 layers
- B32B 2250/244: All polymers belonging to those covered by group B32B27/36
- B32B 2264/02: Synthetic macromolecular particles
- B32B 2264/102: Oxide or hydroxide
- B32B 2264/1021: Silica
- B32B 2270/00: Resin or rubber layer containing a blend of at least two different polymers
- B32B 2307/306: Resistant to heat
- B32B 2307/308: Heat stability
- B32B 2307/31: Heat sealable
- B32B 2307/518: bi-axially
- B32B 2307/70: Other properties
- B32B 2307/702: Amorphous
- B32B 2307/714: Inert, i.e. inert to chemical degradation, corrosion
- B32B 2307/73: Hydrophobic
- B32B 2307/732: Dimensional properties
- B32B 2307/746: Slipping, anti-blocking, low friction
- B32B 2307/748: Releasability
- B32B 2311/00: Metals, their alloys or their compounds
- B32B 2311/30: Iron, e.g. steel
- B32B 2367/00: Polyesters, e.g. PET, i.e. polyethylene terephthalate
- B32B 2439/66: Cans, tins
- B32B 2439/70: Food packaging
- B65D 81/34: for packaging foodstuffs {or other articles} intended to be cooked or heated within the package
- C08J 2367/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds; (C08J2367/06 takes precedence)
- C08J 2483/04: Polysiloxanes
- C08K 3/32: Phosphorus-containing compounds
- C08K 3/36: Silica
- C08K 2003/321: {Phosphates}
- C08K 2003/324: {Alkali metal phosphate}
- C08K 2003/329: {Phosphorus containing acids}
- C08L 67/03: the dicarboxylic acids and dihydroxy compounds having the carboxyl- and the hydroxy groups directly linked to aromatic rings
- C08L 83/04: Polysiloxanes
- C08L 2203/16: used for films
- C08L 2205/02: containing two or more polymers of the same C08L -group
- 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
- Y10T 428/31681: Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
- Y10T 428/31786: Of polyester [e.g., alkyd, etc.]
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B65D: CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- 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)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Embodiments herein relates to a Bisphenol A-free multi-layer biaxially oriented polyester (BOPET) film, for lamination on metal sheets, which could be used for food containers. The BOPET film has at least one outer release layer, which aids in the release of food, such as a high protein food source, when food is cooked and sterilized in direct contact with the outer release layer. The BOPET film can be laminated to metals used in the manufacture of food containers with the outer release layer being exposed to allow a direct food contact between the surface of the outer release layer and food. More particularly, the invention relates to a novel outer release layer resin composition comprising an ultra high molecular weight siloxane polymer and a polyethylene trephthalate resin; and an alkali-metal phosphate and a phosphoric acid compound added, during polymerization of the outer release layer resin composition, as a catalyst/additive package to the ingredients forming the outer release layer resin composition. A wax component can be added in the outer release layer, for more robust release performance.

## Claims

### Claim 1

A polyester film comprising an outer release layer (Layer A) and a core layer (Layer B);
the outer release layer comprising: (a) about 93 wt. % to 99.9 wt. % of a polyethylene terephthalate resin P1, the polyethylene terephthalate resin P1 comprising (i) an alkali metal phosphate in an amount of 1.3 mol/ton of the polyester resin P1 to 3.0 mol/ton of the polyester resin P1, and (ii) phosphoric acid in an amount of from 0.4 to 1.5 times by mole that of the alkali metal phosphate, (b) 0.1-2 wt. % of a silicone resin comprising a polydimethylsiloxane resin, and (c) 0.1-3 wt. % silica; and
the core layer comprising a polyester resin P2 and about 15 wt % to about 45 wt % of polybutylene terephthalate (PBT);
wherein the polyester film is free of Bisphenol A, and wherein weight percentages of said (a), said (b), and any optional one or more additional ingredients in the outer release layer total 100 wt. %, and
wherein the outer release layer is free of wax and has a food area coverage of about 5% or less as measured according to Food Release Test;
wherein the silicone resin has a kinematic viscosity ranging from 10-5×106 centistokes at room temperature.

### Claim 2 (depends on 1)

The polyester film of claim 1, wherein the core layer comprises about 30 wt % to about 45 wt % of polybutylene terephthalate.

### Claim 3 (depends on 1)

The polyester film of claim 1, further comprising a heat-sealable layer (Layer C) comprising (a2) 0.1 to less than 100 wt. % of the polyester resin P2, wherein the polyester resin P2 is crystallizable and different from the polyester resin P1, (b2) 0.1 to less than 100 wt. % an amorphous copolyester resin or a polyester resin having a melting point of least 20° C. below that of the polyester resin P2, and (c2) 0.1-15 wt. % of an antiblock comprising organic or inorganic particles; and
wherein the outer release layer, the core layer and the heat-sealable layer are in this order.

### Claim 4 (depends on 3)

The polyester film of claim 3, wherein the polyester resin P2 comprises an aromatic polyester.

### Claim 5 (depends on 3)

The polyester film of claim 3, wherein the polyester resin P2 comprises at least 50 wt. % ethylene terephthalate as a constituent component of the polyester resin P2.

### Claim 6 (depends on 3)

The polyester film of claim 3, where the polyester resin having a melting point of least 20° C. below that of the polyester resin P2 comprises butylene terephthalate repeat units.

### Claim 7 (depends on 3)

A laminated metal sheet comprising the polyester film of claim 3.

### Claim 8 (depends on 1)

A laminated metal sheet comprising the polyester film of claim 1.