US4664866A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for preparing a film having preferential one-sided cling
Assignee: Dow Chemical Co
•
Filing: 1985-02-15
•
Granted: 1987-05-12
•
Expires: 2005-02-15
Abstract
Abstract A polymeric film having preferential one-sided cling is prepared from a relatively crystalline polymer such as a copolymer of ethylene and an α-olefin having at least 3 carbon atoms, e.g., 1-octene (linear low density polyethylene); a relatively amorphous polymer such as low density polyethylene and a tackifying polymer such as a low molecular weight polybutene by extruding a film of the blend at melt temperatures and subsequently cooling the two sides of the extruded film at different rates. In addition to preferential one-sided cling, a film of a low density polyethylene, linear low density polyethylene and a low molecular weight polybutene which exhibits excellent film strengths and high resistance to tear, particularly in the cross direction, is prepared.
Inventors
- 👤 Lambertus P. P. M. van der Heijden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:48
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; C08L; C08L23/00; C08L23/02; C08L23/04; C08L23/06; C08L23/08; C08L23/0807; C08L23/0815; C08J2323/00; C08J2323/02; C08J2323/04; C08L2205/00; C08L2205/03; C08L23/18; C08L23/20; C08L23/22
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
126 words
A method for preparing a film having one surface exhibiting a higher cling than the opposite surface, said method comprising: (a) blending a first polymer, a second polymer and sufficient amounts of tackifying agent to impart increased cling to at least one surface of the resulting film; the second polymer having a degree of crystallinity, of at least five percent, absolute, higher than the first polymer, (b) extruding the blend as a film at temperatures sufficient to maintain the blend as a liquid, and (c) cooling the two surfaces of the extruded film at sufficiently different rates to prepare a film having one surface cooled at the lower rate which has higher cling than the cling exhibited by the opposite surface cooled at the higher rate.
Claim 2
Independent Claim
126 words
A method for preparing a film having one surface exhibiting a higher cling than the opposite surface, said method comprising: (a) blending a first polymer, a second polymer and sufficient amounts of tackifying agent to impart increased cling to at least one surface of the resulting film; the second polymer having a degree of crystallinity, of at least five percent, absolute, higher than the first polymer, (b) extruding the blend as a film at temperatures sufficient to maintain the blend as a liquid, and (c) cooling the two surfaces of the extruded film at sufficiently different rates to prepare a film having one surface cooled at the lower rate which has higher cling than the cling exhibited by the opposite surface cooled at the higher rate.
Claim 3
Dependent Claim
49 words
The method of claim 1 wherein the tackifying agent is atactic polypropylene or a polymer of isobutylene and the tackifying agent is employed in an amount of from about 3 to about 8 weight percent, based on the total weight of the first and second polymers and tackifying agent.
Claim 4
Dependent Claim
24 words
The method of claim 2 wherein the tackifying agent is atactic polypropylene having a number average molecular weight from about 2000 to about 4000.
Claim 5
Dependent Claim
26 words
The method of claim 2 wherein the tackifying agent is a polymer of isobutylene having a number average molecular weight from about 600 to about 1500.
Claim 6
Dependent Claim
36 words
The method of claim 2 wherein the first polymer has a degree of crystallinity from about 20 to about 40 percent, the second polymer has a degree of crystallinity from about 35 to about 80 percent.
Claim 7
Dependent Claim
55 words
The method of claim 5 wherein the first polymer is a homopolymer of ethylene having a degree of from about 20 to about 35 percent, the second polymer is a copolymer of ethylene with an α-olefin having 3 or more carbon atoms and has a degree of crystallinity from about 35 to about 70 percent.
Claim 8
Dependent Claim
41 words
The method of claim 6 wherein the second polymer is a copolymer of from about 85 to about 99 mole percent polymerized ethylene and from about 15 to about 1 mole percent of polymerized α-olefin having 3 or more carbon atoms.
Claim 9
Dependent Claim
67 words
The method of claim 7 wherein the first polymer has a degree of crystallinity from about 20 to about 30 percent, the second polymer is a copolymer of ethylene with 1-butene or 1-octene and has a degree of crystallinity from about 40 to about 50 percent and the tackifying agent is a polymer of isobutylene having a number average molecular weight from about 800 to about 1200.
Claim 10
Independent Claim
43 words
The method of claims 1, 2, 4 or 7 wherein the film is prepared by extruding a melt of the blend to form a tubular film and one surface of the tubular film is cooled at a higher rate than the opposite surface.
Claim 11
Dependent Claim
40 words
The method of claim 9 wherein the tubular film is cooled by passing air or other suitable gas over the exterior surface of the tubular film while applying no direct, external cooling to the interior surface of the tubular film.
Claim 12
Dependent Claim
17 words
The method of claim 10 wherein the frost line height is from 2 to about 15 cm.
References Cited (Backward Citations)
US2461975A
Cited
US3309452A
Cited
US3349154A
Cited
US3423274A
Cited
US3822333A
Cited
US4255381A
Cited
US4087505A
Cited
GB1578063A
Cited
US4222913A
Cited
EP0011930A1
Cited
US4311808A
Cited
US4337188A
Cited
US4425268A
Cited
US4436788A
Cited
US4362835A
Cited
US4394474A
Cited
US4367256A
Cited
US4518654A
Cited
US4518654B1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-05-11 | 1990-11-10 | 1991-05-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-11 | 1994-11-10 | 1995-05-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-11 | 1998-11-10 | 1999-05-12 | $7700.00 | Window Closed / Lapsed |