US5628957A Expired / Lapsed US ⏱️ 0.0 years remaining

Method of forming multilayer container with polyethylene naphthalalte (pen)

Assignee: Graham Packaging Pet Technologies Inc

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Filing: 1994-12-05

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Granted: 1997-05-13

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Expires: 2014-12-05

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Abstract

Abstract A multilayer preform and container, and method of forming the same, having at least one layer including polyethylene naphthalate (PEN) to provide enhanced oxygen barrier performance and thermal stability. The PEN layer may be a homopolymer, copolymer, or blend of PEN. In a first high-PEN embodiment, the exterior layer contains on the order of 80-100% PEN and 0-20% PET by total weight of the layer, and a core layer of a non-strain hardenable polyester such as PETG. In a second low-PEN embodiment, the exterior layer includes a strain hardenable low-PEN copolymer or blend including on the order of 1-20% PEN and 80-99% PET, and the core layer is a strain-hardenable polyester such as a low-copolymer PET. In a third mid-range PEN embodiment, the exterior wall includes a substantially amorphous PEN copolymer or blend containing on the order of 20-80% PEN and 80-20% of another polyester such as PET, and a strain-hardened core layer of polyester such as a low-copolymer PET. To further enhance the oxygen barrier and thermal stability properties, the core layer may further include a copolymer or blend of PEN. Alternatively, PEN may be provided in an interior layer only.

Inventors

👤 Wayne N. Collette
👤 Steven L. Schmidt
👤 Suppayan M. Krishnakumar

Bibliographic Details

Application Number —

Jurisdiction US

Data Source google_patents

Last Synchronized 2026-11-05 21:49

CPC Classifications

B; B32; B32B; B32B1/00; B29; B29C; B29C49/00; B29C49/22; B29C49/0005; B29C49/0006; B29C49/42; B29C49/64; B29C49/6409; B32B27/00; B32B27/06; B32B27/08; B32B27/36; B65; B65D; B65D1/00; B65D1/02; B65D1/0207; B65D1/0215; B29C49/78; B29C2049/7879; B29C2949/00; B29C2949/07; B29C2949/0715; B29C2949/079; B29C2949/08; B29C2949/081; B29C2949/0811; B29C2949/0817; B29C2949/082; B29C2949/0826; B29C2949/0829; B29C2949/0861; B29C2949/0862; B29C2949/30; B29C2949/3008; B29C2949/3009; B29C2949/3012; B29C2949/3016; B29C2949/302; B29C2949/3024; B29C2949/3026; B29C2949/3028; B29C2949/303; B29C2949/3032; B29C2949/3034; B29C2949/3036; B29C2949/3038; B29C49/02; B29C49/06; B29C49/08; B29C49/087; B29C49/42394; B29C49/6604; B29C49/6605; B29K; B29K2067/00; B29K2105/00; B29K2105/25; B29K2105/253; B29K2105/258; B29K2105/26; B29K2995/00; B29K2995/0018; B29K2995/0026; B29K2995/0037; B29K2995/004; B29K2995/0041; B29K2995/0043; B29K2995/0065; B29K2995/0067; B29K2995/0068; B29K2995/0069; B29L; B29L2009/00; B29L2031/00; B29L2031/712; B29L2031/7158; B32B2250/00; B32B2250/24; B32B2250/244; B32B2307/00; B32B2307/40; B32B2307/412; B32B2367/00; B32B2439/00; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/1352; Y10T428/1379; Y10T428/1383; Y10T428/139; Y10T428/1393; Y10T428/31504; Y10T428/31786

Claims Analysis

Total Claims: 43

Claim 1

Independent Claim 177 words

A method of forming a container having a substantially transparent multilayer sidewall comprising; forming at an elevated temperature a preform having a substantially amorphous and transparent multilayer sidewall-forming portion including first and third layers of a first polymeric material and a second core layer between the first and third layers of a second polymeric material; wherein the first polymeric material comprises on the order of 80-100% PEN and 0-20% PET by total weight of the layer, and the second polymeric material is a substantially nonstrain-crystallizable polyester which remains substantially transparent when stretched-within an orientation temperature range of the first polymeric material; cooling below the glass transition temperature of the first polymeric material and then reheating the preform within the orientation temperature range of the first polymeric material, wherein the preform is reheated from the exterior such that heat is transferred across the core layer; and expanding the sidewall-forming portion within the orientation temperature range of the first polymeric material to form a container having a substantially transparent multilayer sidewall with strain-crysttallized layers of the first polymeric material.

Claim 2

Independent Claim 177 words

Claim 3

Dependent Claim 23 words

The method of claim 1, wherein the second polymeric material is a) PETG; or b) a copolymer or blend of PEN and PETG.

Claim 4

Dependent Claim 33 words

The method of claim 1, wherein the second polymeric material is a copolymer or blend of PEN and PET copolymer, and the PET copolymer comprises on the order of up to 10% copolymer.

Claim 5

Dependent Claim 40 words

The method of claim 2, wherein the first polymeric material comprises on the order of 90% PEN and 10% PET, the second polymeric material comprises PETG, and the thickness ratio of the first:second:third layers is on the order of 25:50:25.

Claim 6

Dependent Claim 41 words

The method of claim 1, wherein the first polymeric material comprises on the order of 1-20% PEN and 80-99% PETG, and the second polymeric material comprises on the order of 80-100% PEN and 0-20% PET by total weight of the layer.

Claim 7

Dependent Claim 41 words

The method of claim 1, wherein the first polymeric material comprises on the order of 1-20% PEN and 80-99% PETG, and the second polymeric material comprises on the order of 20-80% PEN and 20-80% PET by total weight of the layer.

Claim 8

Dependent Claim 61 words

The method of claim 1, wherein the first polymeric material comprises on the order of 80-100% PEN and 0-20% PET by total weight of the layer, and the second polymeric material comprises on the order of 80-100% PEN and 0-20% PET copolymer by total weight of the layer, where the PET copolymer comprises on the order of up to 10% copolymer.

Claim 9

Dependent Claim 36 words

The method of claim 1, wherein the reheating and expanding is performed at an orientation temperature which is on the order of 11° to 36° C. above the glass transition temperature of the first polymeric material.

Claim 10

Dependent Claim 36 words

The method of claim 8, wherein the reheating and expanding is performed at an orientation temperature which is on the order of 17° to 22° C. above the glass transition temperature of the first polymeric material.

Claim 11

Dependent Claim 24 words

The method of claim 9, wherein the sidewall includes a panel portion which is expanded at a planar stretch ratio of at least 12:1.

Claim 12

Dependent Claim 20 words

The method of claim 10, wherein the panel portion is expanded at a planar stretch ratio of at least 15:1.

Claim 13

Dependent Claim 27 words

The method of claim 11, wherein the sidewall has a panel portion having an average strain-induced crystallinity of at least 15% in the first and third layers.

Claim 14

Dependent Claim 23 words

The method of claim 12, wherein the panel portions has an average strain-induced crystallinity of at least 20% in the first end-third layers.

Claim 15

Dependent Claim 20 words

The method of claim 1, wherein the first polymeric material has no greater than 10% by weight of isophthalic acid.

Claim 16

Dependent Claim 17 words

The method of claim 1, wherein the first polymeric material is a blend of PEN and PET.

Claim 17

Dependent Claim 17 words

The method of claim 1, wherein the first polymeric material is a copolymer of PEN and PET.

Claim 18

Dependent Claim 45 words

The method of claim 1, wherein the second polymeric material is selected from the group consisting of: (a) a PET copolymer with 30% cyclohexane dimethanol (PETG); (b) a copolymer or blend of PEN and PETG; and (c) a copolymer or blend of PEN and PET.

Claim 19

Dependent Claim 16 words

The method of claim 1, wherein the core layer comprises about 50% of the sidewall thickness.

Claim 20

Dependent Claim 21 words

The method of claim 1, wherein the sidewall has a panel portion having a wall thickness of 0.5 to 0.8 mm.

Claim 21

Dependent Claim 19 words

The method of claim 1, wherein the level of crystallinity in the sidewall is further enhanced by thermal-induced crystallinity.

Claim 22

Dependent Claim 26 words

The method of claim 1, wherein the sidewall further includes one or more layers of barrier materials, high thermal stability materials, recycled PET, or post-consumer PET.

Claim 23

Dependent Claim 39 words

The method of claim 1, wherein the article is a container able to withstand at least 20 refill cycles at a caustic wash temperature of 60° C. without crack failure and with a maximum total volume change of +1.5%.

Claim 24

Dependent Claim 14 words

The method of claim 1, wherein the article is a freestanding pressurized beverage container.

Claim 25

Dependent Claim 12 words

The method of claim 1, wherein the article is a hot-fill container.

Claim 26

Independent Claim 193 words

A method of forming a container having a substantially transparent multilayer sidewall comprising; forming at an elevated temperature a preform having a substantially amorphous and transparent multilayer sidewall-forming portion including first and third layers of a first polymeric material and a second core layer between the first and third layers of a second polymeric material; wherein the first polymeric material comprises on the order 80-100% PEN and and 0-20% PET by total weight of the layer, and the second polymeric material is substantially nonstrain-crystallizable polyester which remains substantially transparent when stretched within an orientation, temperature range of the first polymeric material; cooling below the glass transition temperature of the first polymeric material and then reheating the preform from the exterior such that heat is transferred across the core layer, wherein the reheating and expanding is performed at an orientation temperature which is on the order of 11° to 36° C. above the glass transition temperature of the first polymeric material; and expanding the sidewall-forming portion within the orientation temperature range of the first polymeric material to form a container having a substantially transparent multilayer sidewall with strain-crystallized layers of the first polymeric material.

Claim 27

Independent Claim 193 words

A method of forming a container having a substantially transparent multilayer sidewall comprising; forming at an elevated temperature a preform having a substantially amorphous and transparent multilayer sidewall-forming portion including first and third layers of a first polymeric material and a second core layer between the first and third layers of a second polymeric material; wherein the first polymeric material comprises on the order 80-100% PEN and and 0-20% PET by total weight of the layer, and the second polymeric material is substantially nonstrain-crystallizable polyester which remains substantially transparent when stretched within an orientation, temperature range of the first polymeric material; cooling below the glass transition temperature of the first polymeric material and then reheating the preform from the exterior such that heat is transferred across the core layer, wherein the reheating and expanding is performed at an orientation temperature which is on the order of 11° to 36° C. above the glass transition temperature of the first polymeric material; and expanding the sidewall-forming portion within the orientation temperature range of the first polymeric material to form a container having a substantially transparent multilayer sidewall with strain-crystallized layers of the first polymeric material.

Claim 28

Independent Claim 207 words

A method of forming a container having a substantially transparent multilayer sidewall, including forming at an elevated temperature a preform having a substantially amorphous and transparent multilayer sidewall-forming portion including a first layer of a first polymeric material and a second layer of a second polymeric material, cooling and then reheating and expanding the preform to form the container, characterized in that: the first polymeric material is a copolymer or blend which is substantially non-crystallizable and contains both polyethylene naphthalate (PEN) and polyethylene terephthalate (PET), and the second polymeric material is strain-hardened and remains substantially transparent when stretched at a temperature within the orientation temperature range of the first polymeric material; cooling is performed below the glass transition temperature of the first polymeric material and then reheating of the first and second layers is performed within the orientation temperature range of the first polymeric material which is on the order of 11° to 36° C. above the glass transition temperature of the first polymeric material; and expanding of the preform is performed within the orientation temperature range of the first polymeric material to form a container having a substantially transparent multilayer sidewall with a substantially amorphous first polymeric material layer and a strain-hardened second polymeric material layer.

Claim 29

Independent Claim 207 words

Claim 30

Dependent Claim 47 words

The method of claim 26, further including a third layer of the first polymeric material and wherein the second layer is a core layer between the first and third layers and the preform is reheated from the exterior such that heat is transferred across the core layer.

Claim 31

Independent Claim 25 words

The method of any one of claims 26 and 27, wherein the first polymeric material comprises on the order of 20-80% PEN and 80-20% PET.

Claim 32

Dependent Claim 27 words

The method of claim 28, wherein the second polymeric material is a PET copolymer, and the PET copolymer comprises on the order of up to 10% copolymer.

Claim 33

Dependent Claim 24 words

The method of claim 28, wherein the sidewall includes a panel portion which is expanded at a planar stretch ratio of at least 12:1.

Claim 34

Dependent Claim 20 words

The method of claim 28, wherein the panel portion is expanded at a planar stretch ratio of at least 15:1.

Claim 35

Dependent Claim 18 words

The method of claim 31, wherein the panel portion is expanded at a planar stretch ratio of 15-20:1.

Claim 36

Dependent Claim 25 words

The method of any one of claim 28, wherein the panel portion has an average strain-induced crystallinity of at least 15% in the second layer.

Claim 37

Dependent Claim 20 words

The method of claim 33, wherein the panel portion has an average strain-induced crystallinity of 15-25% in the second layer.

Claim 38

Dependent Claim 25 words

The method of claim 28, wherein the first polymeric material is on the order of 50% PEN and 50% PET by total weight of the-layer.

Claim 39

Dependent Claim 21 words

The method of claim 28, wherein the sidewall has a panel portion having a wall thickness of 0.5 to 0.8 mm.

Claim 40

Dependent Claim 19 words

The method of claim 28, wherein the thickness ratio of the first:second:third layers is on the order of 30:40:30.

Claim 41

Dependent Claim 19 words

The method of claim 28, wherein the thickness ratio of the first:second:third layers is on the order of 15:70:15.

Claim 42

Dependent Claim 26 words

The method of claim 28, wherein the sidewall further includes one or more layers of barrier materials, high thermal stability materials, recycled PET, or post-consumer PET.

Claim 43

Dependent Claim 29 words

The method of claim 28, wherein the orientation temperature range is on the order of 17° to 22° C. above the glass transition temperature of the first polymeric material.

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USPTO Annuity & Maintenance Windows

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2000-05-12	2000-11-11	2001-05-13	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2004-05-12	2004-11-11	2005-05-13	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2008-05-12	2008-11-11	2009-05-13	$7700.00	Window Closed / Lapsed

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