US4636340A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing crosslinked polyethylene stretched film
Assignee: Tonen General Sekiyu KK
•
Filing: 1984-12-18
•
Granted: 1987-01-13
•
Expires: 2004-12-18
Abstract
Abstract An oriented film is prepared by crosslinking a sheet of polyethylene (preferably HDPE) containing particulate inorganic slip and antiblock additions to provide maximum crosslinking at the surfaces of the sheet and minimum orientation at its middle layer portion, and thereafter heating and stretching the film to obtain an oriented HDPE of high clarity film of improved moisture proof.
Inventors
- 👤 Yasushi Itaba
- 👤 Tadao Yoshino
- 👤 Yutaka Yoshifuji
- 👤 Keichiro Saito
- 👤 Jyoichi Tabuchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:48
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/24; C08J3/245; B; B29; B29C; B29C55/00; B29C55/02; C08J5/00; C08J5/18; B29K; B29K2023/00; B29K2023/04; B29K2023/06; C08J2323/00; C08J2323/02; C08J2323/04; C08J2323/06; Y; Y10; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/268; Y10T428/31504; Y10T428/31855
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
122 words
A method for producing high clarity oriented polyethylene film which comprises (a) crosslinking opposite surfaces of a sheet of polyethylene having a density greater than 0.935 and containing from 0.02 to 1 parts by weight per 100 parts by weight of said polyethylene of a particulate inorganic compound selected from the group consisting of zeolite, silica, alumina, and bentonite, having an average particle size less than 20 microns, said crosslinking produces gel fractions in opposite outer layer portions of the sheet of between 20% and 70% and a gel fraction in a middle layer portion of the sheet of between 0 and 5%, (b) heating and stretching the crosslinked sheet under conditions to orient the polyethylene molecules thereby producing an oriented film.
Claim 2
Independent Claim
122 words
A method for producing high clarity oriented polyethylene film which comprises (a) crosslinking opposite surfaces of a sheet of polyethylene having a density greater than 0.935 and containing from 0.02 to 1 parts by weight per 100 parts by weight of said polyethylene of a particulate inorganic compound selected from the group consisting of zeolite, silica, alumina, and bentonite, having an average particle size less than 20 microns, said crosslinking produces gel fractions in opposite outer layer portions of the sheet of between 20% and 70% and a gel fraction in a middle layer portion of the sheet of between 0 and 5%, (b) heating and stretching the crosslinked sheet under conditions to orient the polyethylene molecules thereby producing an oriented film.
Claim 3
Dependent Claim
12 words
The method as defined in claim 1 wherein the polyethylene is HDPE.
Claim 4
Dependent Claim
43 words
The method as defined in claim 1 wherein the outer layer portions are crosslinked film and the middle layer portion is an uncrosslinked film, and the thickness ratio of the outer layer portion:middle layer portion:outer layer portion thereof ranging between 1:0.1:1 to 1:10:1.
Claim 5
Dependent Claim
19 words
The method as defined in claim 1 wherein the sheet is crosslinked by irradiating both surfaces of said sheet.
Claim 6
Dependent Claim
19 words
The method as defined in claim 1 wherein the sheet comprises crosslinked layers coextruded onto an uncrosslinked middle layer.
Claim 7
Dependent Claim
32 words
The method as defined in claim 3 wherein the sheet has a thickness of from 210 to 2000 microns and the stretching at least in one direction is at least 300 percent.
Claim 8
Dependent Claim
17 words
The method as defined in claim 1 wherein the crosslinking is carried out in an inert environment.
References Cited (Backward Citations)
US2936261A
Cited
US3187982A
Cited
US3201506A
Cited
US3448182A
Cited
GB1270954A
Cited
US3563870A
Cited
DE1943101A1
Cited
US3886056A
Cited
US4101699A
Cited
JPS5375278A
Cited
JPS5443274A
Cited
US4226905A
Cited
GB2040804A
Cited
DE2911777A1
Cited
US4590020A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-01-12 | 1990-07-14 | 1991-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-12 | 1994-07-14 | 1995-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-12 | 1998-07-14 | 1999-01-13 | $7700.00 | Window Closed / Lapsed |