US4066811A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ethylene-vinyl acetate film suitable for stretch wrapping
Assignee: Asahi Kasei Corp
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Filing: 1975-04-08
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Granted: 1978-01-03
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Expires: 1995-04-08
Abstract
Abstract There are disclosed films for stretch wrapping which comprise an olefin polymer, preferably a specific ethylene-vinyl acetate copolymer (referred to as "EVA copolymer" hereinafter) and specific polyalkylene ether polyols and non-ionic surfactants of fatty acid and polyhydric alcohol ester derivatives and which have suitable orientation expressed by heat shrinkage and excellent elastic recovery, by which excellent mechanical strength, wrapping finish, optical characteristics and preservability of the goods, especially fresh foods are attained. Method for producing said films is also disclosed. These films are suitable also for wrapping by automatic wrapping machines.
Inventors
- 👤 Hirokuni Naito
- 👤 Isao Yoshimura
- 👤 Norito Takao
- 👤 Yasuta Kawame
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:59
CPC Classifications
C; C08; C08K; C08K5/00; C08K5/04; C08K5/06; C08K5/10; C08K5/101; C08K5/103; C08L; C08L23/00; C08L23/02; C08L23/04; C08L23/08; C08L23/0846; C08L23/0853; C08L71/00; C08L71/02
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
166 words
Films for stretch wrapping which comprise (1) 99.7-98% by weight of an ethylene-vinyl acetate copolymer having a melt index of 0.5-15 and containing 5-30% by weight of vinyl acetate and (2) 0.3-2% by weight of an additive, said additive comprising (A) 10-40% by weight of at least one polyalkylene ether polyol having a boiling point of at least 200° C. at 760 mm. Hg and a viscosity of less than 1,000 cps at 23° C. and (B) 90-60% by weight of at least one non-ionic surfactant which is an ester of a polyhydric alcohol with either a straight chain saturated fatty acid having an alkyl group of 5 to 13 carbon atoms or a straight chain unsaturated fatty acid having an alkyl group of 17 to 21 carbon atoms, said films having a kinetic coefficient of friction of 0.1-0.5, a tack strength of 0.4-1.5 kg/cm 2 , a haze of less than 5%, a heat shrinkage of 30-80% and an elastic recovery of at least 60%.
Claim 2
Dependent Claim
166 words
Films for stretch wrapping which comprise (1) 99.7-98% by weight of an ethylene-vinyl acetate copolymer having a melt index of 0.5-15 and containing 5-30% by weight of vinyl acetate and (2) 0.3-2% by weight of an additive, said additive comprising (A) 10-40% by weight of at least one polyalkylene ether polyol having a boiling point of at least 200° C. at 760 mm. Hg and a viscosity of less than 1,000 cps at 23° C. and (B) 90-60% by weight of at least one non-ionic surfactant which is an ester of a polyhydric alcohol with either a straight chain saturated fatty acid having an alkyl group of 5 to 13 carbon atoms or a straight chain unsaturated fatty acid having an alkyl group of 17 to 21 carbon atoms, said films having a kinetic coefficient of friction of 0.1-0.5, a tack strength of 0.4-1.5 kg/cm 2 , a haze of less than 5%, a heat shrinkage of 30-80% and an elastic recovery of at least 60%.
Claim 3
Dependent Claim
23 words
Films according to claim 1, wherein the mixing ratio of aditives is 15-35% by weight of (A) and 85-65% by weight of (B).
Claim 4
Dependent Claim
19 words
Films according to claim 1, wherein the total amount of the additives (A) and (B) is 0.5-1.5% by weight.
Claim 5
Dependent Claim
30 words
Films according to claim 1, wherein the ethylene-vinyl acetate copolymer has a melt index of 1 to 10 and a vinyl acetate group content of 5 to 20% by weight.
Claim 6
Dependent Claim
24 words
Films according to claim 1, wherein the polyalkylene ether polyol (A) is polyethylene glycol having a number average molecular weight of 200 to 600.
Claim 7
Dependent Claim
24 words
Films according to claim 1, wherein the polyalkylene ether polyol (A) is polypropylene glycol having a number average molecular weight of 400 to 3000.
Claim 8
Dependent Claim
41 words
Films according to claim 1, wherein the ester is monoester, diester or mixed mono- and di-ester of a fatty acid selected from lauric acid, oleic acid, and erucic acid and a polyhydric alcohol selected from glycerine, polyglycerine, sorbitan, sorbitol and pentaerythritol.
Claim 9
Dependent Claim
14 words
Films according to claim 1, wherein the non-ionic surfactant (B) a polyoxyethylene addition product.
Claim 10
Dependent Claim
14 words
Films according to claim 1, which have a thickness of 10 to 30 μ.
Claim 11
Dependent Claim
16 words
Films according to claim 1, which have a kinetic coefficient of friction of 0.1 to 0.45.
Claim 12
Dependent Claim
17 words
Films according to claim 1, which have a tack strength of 0.5 to 1.5 kg/cm 2 .
Claim 13
Dependent Claim
14 words
Films according to claim 1, which have an elastic recovery of at least 70%.
Claim 14
Dependent Claim
25 words
Films according to claim 1, which have an ultimate elongation of at least 200% and a stress at 200% elongation of 100 to 500 g/cm.
Claim 15
Dependent Claim
17 words
Films according to claim 1, which have a drop dart impact strength of at least 10 kg.cm.
References Cited (Backward Citations)
US3658980A
Cited
FR2117386A5
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-01-02 | 1981-07-04 | 1982-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-02 | 1985-07-04 | 1986-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-02 | 1989-07-04 | 1990-01-03 | $7700.00 | Window Closed / Lapsed |