# US 12,595,346 B2 · Polyolefin-based composition for a lid and methods of making and using

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- Number: US 12,595,346 B2
- Document ID: US12595346B2
- Status: Granted
- Kind: B2
- Application number: 18/678,555
- Filed: 2024-05-30
- Published: 2024-09-19
- Granted: 2026-04-07
- Earliest claimed: 2017-10-10
- Assignees: Dart Container Corporation
- Applicants: Dart Container Corporation
- Inventors: Chengtao Li; Robert Allan Brubaker; Jacob Christopher Purcell
- Web page: https://patentgrep.com/patent/US12595346B2

## CPC

- C08J 9/0066: {Use of inorganic compounding ingredients}
- B65D 43/0202: {without integral tamper element}
- B65D 65/38: Packaging materials of special type or form
- C08J 9/08: developing carbon dioxide
- C08J 9/10: developing nitrogen {, the blowing agent being a compound containing a nitrogen-to-nitrogen bond}
- C08J 9/36: After-treatment (C08J9/22 takes precedence)
- B32B 27/20: using fillers, pigments, thixotroping agents
- B32B 27/32: comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)}
- B65D 2543/00092: circular
- B65D 2543/00296: Plastic
- B65D 2543/00351: Dome-like
- C08J 2201/03: Extrusion of the foamable blend
- C08J 2203/02: CO2-releasing, e.g. NaHCO3 and citric acid
- C08J 2203/04: N2 releasing, ex azodicarbonamide or nitroso compound
- C08J 2205/044: Micropores, i.e. average diameter being between 0,1 micrometer and 0,1 millimeter
- C08J 2205/10: Rigid foams
- C08J 2323/12: Polypropene
- 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)
- 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
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM

## Abstract

Aspects of the present disclosure relate to a polyolefin composition and processes suitable for use in forming a lid for a hot food or beverage container that has a stiffness comparable to a similar lid made using high impact polystyrene and a density less than water at 23° C.

## Claims

### Claim 1

A thermoformed lid for a food or beverage container, the thermoformed lid made from a non-vented, extruded sheet comprising at least one polyolefin with at least one filler, and having expanded cells providing the thermoformed lid with a density greater than 0 g/cm3 at 23° C. and less than 1 g/cm3 at 23° C.

### Claim 2 (depends on 1)

The thermoformed lid of claim 1 wherein the at least one polyolefin is selected from the group consisting of polypropylene homopolymers, polypropylene impact copolymers, ethylene-propylene copolymers, high density polyethylene, and combinations thereof.

### Claim 3 (depends on 2)

The thermoformed lid of claim 2 wherein the polyolefin comprises a polypropylene having one of:
a flexural modulus of greater than or equal to 290,000 psi;
a heat deflection temperature of at least 95° C.; or
a combination of a flexural modulus of greater than or equal to 290,000 psi and a heat deflection temperature of at least 95° C.

### Claim 4 (depends on 1)

The thermoformed lid of claim 1 wherein the at least one filler is selected from talc, calcium carbonate, mica, wollastonite, wood fiber, paper powder, cellulose fiber, or combinations thereof.

### Claim 5 (depends on 1)

The thermoformed lid of claim 1 wherein a total amount of the at least one filler is greater than 12 wt. % of the sheet and less than or equal to 40 wt. % of the sheet.

### Claim 6 (depends on 1)

The thermoformed lid of claim 1 wherein a stiffness of the thermoformed lid is comparable to a similar thermoformed lid made from unexpanded high impact polystyrene, and wherein stiffness is based on a weight required to induce a 0.25 inch deflection of the thermoformed lid when the thermoformed lid is placed on a cup holding liquid at 200° F.

### Claim 7 (depends on 1)

The thermoformed lid of claim 1 wherein the expanded cells have an average cell diameter in a range of 0.01 to 0.15 mm.

### Claim 8 (depends on 1)

The thermoformed lid of claim 1 comprising:
a flexural modulus of greater than or equal to 290,000 psi;
a heat deflection temperature of at least 95° C.;
a density in a range of 0.900 to 0.999 g/cm3; and
a shrinkage rate of 1.3 to 1.5% during storage.

### Claim 9 (depends on 1)

The thermoformed lid of claim 1 wherein the expanded cells are randomly distributed.

### Claim 10

A thermoformed lid for a food or beverage container, the thermoformed lid made from a non-vented, extruded and expanded sheet comprising a polyolefin blend having at least one polyolefin and at least one filler, a blowing agent, and having a plurality of expanded cells with an average cell diameter in a range of 0.01 to 0.15 mm, and a density less than water at 23° C.

### Claim 11 (depends on 10)

The thermoformed lid of claim 10 wherein the thermoformed lid has a density in a range of 0.900 to 0.999 g/cm3.

### Claim 12 (depends on 11)

The thermoformed lid of claim 11 wherein the thermoformed lid comprises at least one of:
a stiffness of the thermoformed lid is comparable to a similar lid made from unexpanded high impact polystyrene, and wherein stiffness is based on a weight required to induce a 0.25 inch deflection of the thermoformed lid when the thermoformed lid is placed on a cup holding liquid at 200° F.;
a shrinkage rate of 1.3 to 1.5% during storage; or
combinations thereof.

### Claim 13 (depends on 12)

The thermoformed lid of claim 12 wherein the blowing agent is at least one of:
selected from the group consisting of sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, and ammonium nitrite;
present in an amount of 0.2 to 3 wt. %; or
combinations thereof.

### Claim 14 (depends on 10)

The thermoformed lid of claim 10 wherein the polyolefin is selected from the group consisting of polypropylene homopolymers, polypropylene impact copolymers, ethylene-propylene copolymers, high density polyethylene, and combinations thereof.

### Claim 15 (depends on 10)

The thermoformed lid of claim 10 wherein the polyolefin comprises a polypropylene having one of:
a flexural modulus of at least greater than or equal to 290,000 psi;
a heat deflection temperature of at least 95° C.; or
a combination of a flexural modulus of at least greater than or equal to 290,000 psi and a heat deflection temperature of at least 95° C.

### Claim 16 (depends on 10)

The thermoformed lid of claim 10 wherein the at least one filler is selected from talc, calcium carbonate, mica, wollastonite, wood fiber, paper powder, cellulose fiber, or combinations thereof.

### Claim 17 (depends on 16)

The thermoformed lid of claim 16 wherein a total amount of the at least one filler is greater than 12 wt. %.

### Claim 18 (depends on 10)

The thermoformed lid of claim 10 wherein the sheet is expanded to decrease the density by 5 to 10%.

### Claim 19

A thermoformed lid for a food or beverage container, the thermoformed lid made from a non-vented, extruded, and expanded sheet comprising a polyolefin blend having at least one polyolefin and at least one filler, a blowing agent, a plurality of expanded cells providing the thermoformed lid with a density less than water at 23° C., and at least one of:
a stiffness of the thermoformed lid is comparable to a similar lid made from unexpanded high impact polystyrene, and wherein stiffness is based on a weight required to induce a 0.25 inch deflection of the thermoformed lid when the thermoformed lid is placed on a cup holding liquid at 200° F.;
a shrinkage rate of 1.3 to 1.5% during storage; or
combinations thereof.

### Claim 20 (depends on 19)

The thermoformed lid of claim 19 wherein the thermoformed lid has a density in a range of 0.900 to 0.999 g/cm3.

### Claim 21 (depends on 19)

The thermoformed lid of claim 19 wherein the blowing agent is at least one of:
selected from the group consisting of sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, and ammonium nitrite;
present in an amount of 0.2 to 3 wt. %; or
combinations thereof.

### Claim 22 (depends on 19)

The thermoformed lid of claim 19 wherein the plurality of expanded cells has an average cell diameter in a range of 0.01 to 0.15 mm.

### Claim 23

A thermoformed lid for a food or beverage container, the thermoformed lid made from a non-vented, extruded sheet comprising a polyolefin blend having at least one polyolefin and at least one filler, a blowing agent, with the sheet being at least partially expanded to form a plurality of expanded cells, wherein the thermoformed lid has a density in a range of 0.900 to 0.999 g/cm3 at 23° C.

### Claim 24 (depends on 23)

The thermoformed lid of claim 23 wherein the blowing agent is at least one of:
selected from the group consisting of sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, and ammonium nitrite;
present in an amount of 0.2 to 3 wt. %; or
combinations thereof.

### Claim 25 (depends on 24)

The thermoformed lid of claim 24 wherein the plurality of expanded cells has an average cell diameter in a range of 0.01 to 0.15 mm.

### Claim 26 (depends on 23)

The thermoformed lid of claim 23 wherein the polyolefin is selected from the group consisting of polypropylene homopolymers, polypropylene impact copolymers, ethylene-propylene copolymers, high density polyethylene, and combinations thereof.

### Claim 27 (depends on 23)

The thermoformed lid of claim 23 wherein the polyolefin comprises a polypropylene having one of:
a flexural modulus of at least greater than or equal to 290,000 psi;
a heat deflection temperature of at least 95° C.; or
a combination of a flexural modulus of at least greater than or equal to 290,000 psi and a heat deflection temperature of at least 95° C.

### Claim 28 (depends on 23)

The thermoformed lid of claim 23 wherein the at least one filler is selected from talc, calcium carbonate, mica, wollastonite, wood fiber, paper powder, cellulose fiber, or combinations thereof.

### Claim 29 (depends on 23)

The thermoformed lid of claim 23 wherein a total amount of the at least one filler is greater than 12 wt. %.

### Claim 30 (depends on 23)

The thermoformed lid of claim 23 wherein the sheet is expanded to decrease the density by 5 to 10%.

### Claim 31

A thermoformed lid for a food or beverage container, the thermoformed lid made from a non-vented, at least partially expanded sheet comprising a polyolefin blend with at least one polyolefin with at least one filler, a plurality of expanded cells, and a blowing agent, wherein the blowing agent is at least one of:
selected from the group consisting of sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, and ammonium nitrite;
present in an amount of 0.2 to 3 wt. %; or
combinations thereof;
wherein the thermoformed lid has a density less than water at 23° C.

### Claim 32 (depends on 31)

The thermoformed lid of claim 31 wherein the plurality of expanded cells has an average cell diameter in a range of 0.01 to 0.15 mm.