US4956232A
Expired / Lapsed
US
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Multi-layer heat-sealable polypropylene films
Assignee: Mobil Oil AS
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Filing: 1988-12-27
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Granted: 1990-09-11
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Expires: 2008-12-27
Abstract
Abstract Multi-layer, heat-sealable polypropylene films are disclosed which possess good coefficient of friction, and thus good machinability, and which are also capable of forming good bonds with water based adhesives. The film structures consist essentially of (A) an outer heat sealable layer coextensively adherent to the upper surface of core layer (B), said outer layer (A) being formed from a polymer composition (a) consisting essentially of heat sealable resin compounded with one or more slip additives which are incompatible with polypropylene, (B) a core layer derived from a polymer composition (b) consisting essentially of an isotactic polypropylene compounded with one or more slip additives which are incompatible with polypropylene, and (C) an outer layer coextensively adherent to the lower surface of core layer (B), said outer layer (C) being formed from a polymer composition consisting essentially of isotactic polypropylene in the substantial absence of slip additives; wherein the total amount of slip additive in said film structure is effective to provide the outer surface of outer layer (A) with a coefficient of friction sufficient for high speed heat sealing packaging operations but insufficient to cause substantial hazing of said structure.
Inventors
- 👤 Ricardo Balloni
- 👤 Kevin M. Donovan
- 👤 Jay K. Keung
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 05:58
CPC Classifications
C; C09; C09J; C09J7/00; C09J7/20; C09J7/29; B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B32B27/18; B32B27/30; B32B27/304; B32B27/32; B32B7/00; B32B7/04; B32B7/12; C09J7/22; C09J7/30; C09J7/35; B32B2307/00; B32B2307/30; B32B2307/31; B32B2323/00; B32B2323/10; B32B2327/00; B32B2439/00; B32B2439/70; C09J2301/00; C09J2301/10; C09J2301/16; C09J2301/162; Y; Y10; Y10T; Y10T428/00; Y10T428/28; Y10T428/2813; Y10T428/2817; Y10T428/2826; Y10T428/2848; Y10T428/31504; Y10T428/31551; Y10T428/31573; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/31935
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
165 words
A heat-sealable multi-layer film structure consisting essentially of (A) an outer heat sealable layer coextensively adherent to the upper surface of core layer (B), said outer layer (A) being formed from a polymer composition (a) consisting essentially of heat sealable resin compounded with one or more slip additives which are incompatible with polypropylene, (B) a core layer derived from a polymer composition (b) consisting essentially of an isotactic polypropylene homopolymer compounded with one or more slip additives which are incompatible with polypropylene, and (C) an outer layer coextensively adherent to the lower surface of core layer (B), said outer layer (C) being formed from a polymer composition (c) consisting essentially of isotactic polypropylene homopolymer in the substantial absence of slip additives; wherein the total amount of slip additive in said film structure is effective to provide the outer surface of outer layer (A) with a coefficient of friction sufficient for high speed heat sealing packaging operations but insufficient to cause substantial hazing of said structure.
Claim 2
Dependent Claim
165 words
A heat-sealable multi-layer film structure consisting essentially of (A) an outer heat sealable layer coextensively adherent to the upper surface of core layer (B), said outer layer (A) being formed from a polymer composition (a) consisting essentially of heat sealable resin compounded with one or more slip additives which are incompatible with polypropylene, (B) a core layer derived from a polymer composition (b) consisting essentially of an isotactic polypropylene homopolymer compounded with one or more slip additives which are incompatible with polypropylene, and (C) an outer layer coextensively adherent to the lower surface of core layer (B), said outer layer (C) being formed from a polymer composition (c) consisting essentially of isotactic polypropylene homopolymer in the substantial absence of slip additives; wherein the total amount of slip additive in said film structure is effective to provide the outer surface of outer layer (A) with a coefficient of friction sufficient for high speed heat sealing packaging operations but insufficient to cause substantial hazing of said structure.
Claim 3
Dependent Claim
18 words
The film of claim 1 wherein said heat sealable resin is a terpolymer of propylene, ethylene and 1-butene.
Claim 4
Dependent Claim
25 words
The film of claim 2 wherein said terpolymer comprises about 80-97 wt. % propylene, about 1-10 wt. % ethylene, and about 1-20 wt. % butene-1.
Claim 5
Dependent Claim
24 words
The film of claim 3 wherein said terpolymer comprises about 88-95 wt. propylene, about 2-6 wt. % ethylene, and about 2-15 wt. % butene-1.
Claim 6
Dependent Claim
21 words
The film of claim wherein said heat sealable resin is an ethylene-propylene copolymer containing about 1.5 to 10 wt. % ethylene.
Claim 7
Dependent Claim
18 words
The film of claim 5 in which said ethylenepropylene copolymer contains about 3 to 5 wt. % ethylene.
Claim 8
Dependent Claim
22 words
The film of claim 1 wherein said heat sealable resin is a propylene-butene-1 copolymer containing about 5 to 40 weight percent butene-1.
Claim 9
Dependent Claim
20 words
The film of claim 1 wherein said heat sealable layer (A) further contains between about 5-15 wt. % microcrystalline wax.
Claim 10
Dependent Claim
21 words
The film of claim 1 wherein said heat sealable layer (A) further contains about 0.05 to 0.3 wt. % glycerol monostearate.
Claim 11
Dependent Claim
32 words
The film of claim wherein said heat sealable layer (A) further contains about 0.05-5 wt. % anti-block particles having a mean particle size in the range of about 0.5 to 5 microns.
Claim 12
Dependent Claim
12 words
The film of claim 10 wherein said anti-block particles are silica particles.
Claim 13
Dependent Claim
27 words
The film of claim 1 wherein the amount of slip additive in polymer composition (b) is less than the amount of slip additive in polymer composition (a).
Claim 14
Dependent Claim
16 words
The film of claim 1 wherein the slip additive in compositions (a) and (b) is erucamide.
Claim 15
Dependent Claim
27 words
The film of claim 13 wherein said composition (a) contains about 1000 to 2000 ppm erucamide and said composition (b) contains about 400 to 800 ppm erucamide.
Claim 16
Dependent Claim
30 words
The film of claim 1 wherein said polymer composition (c) further contains about 0.05-0.5 wt. % anti-block particles having a mean particle size ranging from about 0.5 to 5 microns.
Claim 17
Dependent Claim
12 words
The film of claim 15 wherein said anti-block particles are silica particles.
Claim 18
Dependent Claim
25 words
The film of claim 1 wherein the outer surface of outer layer (A) exhibits a coefficient of friction of less than 0.45 at room temperature.
Claim 19
Dependent Claim
25 words
The film of claim 17 wherein the outer surface of outer layer (A) exhibits a coefficient of friction of less than 0.35 at room temperature.
Claim 20
Dependent Claim
23 words
The film of claim 1 wherein the outer surface of outer layer (C) has a surface activity of at least about 36 dynes/cm.
Claim 21
Dependent Claim
23 words
The film of claim 1 which further comprises, adjacent to the outer surface of outer layer (C), a coating of water based adhesive.
Claim 22
Dependent Claim
20 words
The film of claim 20 in which said water based adhesive is selected from acrylics, urethanes, and vinylidene chloride polymer.
Claim 23
Dependent Claim
27 words
The film of claim 20 in which the strength of the bond between said water based adhesive coating and said outer layer (C) is about 80-150 g/in.
Claim 24
Dependent Claim
93 words
The film of claim 1 wherein said heat-sealable resin is a terpolymer of propylene, ethylene and 1-butene comprising about 88-95 wt. % propylene and about 2-6 wt. % ethylene; said heat sealable layer (A) further contains between about 5-15 wt. % microcrystalline wax, and about 0.05 to 0.3 wt. % glycerol monostearate; polymer compositions (a) and /(c) contain silica anti-block particles having a mean particle size of about 0.5 to 5 microns; and polymer composition (a) contains about 1000 to 2000 ppm erucamide and composition (b) contains about 400 to 800 ppm erucamide.
Claim 25
Dependent Claim
25 words
The film of claim 23 wherein the outer surface of outer layer (C) exhibits a coefficient of friction of less than 0.3 at room temperature.
Claim 26
Dependent Claim
23 words
The film of claim 23 which further comprises, adjacent to the outer surface of outer layer (C), a coating of water based adhesive.
Claim 27
Dependent Claim
15 words
The film of claim 25 in which said water based adhesive is vinylidene chloride copolymer.
Claim 28
Dependent Claim
26 words
The film of claim 26 in which the strength of the bond between said vinylidene chloride polymer coating and said outer layer (C) is about 80-1/8g/in.
References Cited (Backward Citations)
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