Heat Sealable Propylene-Based Films

Patent metadata

Field	Value
Publication number	US-2018155538-A1
Application number	US-201715785487-A
Country	US
Kind code	A1
Filing date	Oct 17, 2017
Priority date	Dec 1, 2016
Publication date	Jun 7, 2018
Grant date	—

Abstract

Disclosed herein are multilayer films including at least one layer that comprises and/or is formed from a composition comprising a propylene polymer and a hydrocarbon resin. The films generally further include at least one layer that comprises and/or is made from a composition comprising a propylene-based elastomer and/or a propylene polymer. The multilayer films disclosed herein generally have a low sealing initiation temperature.

First claim

What is claimed is:

1 . A multilayer film comprising:
a first layer, A, wherein the first layer comprises from 1 to 50 wt % of a hydrocarbon resin and from 50 to 99 wt % of a propylene polymer, wherein the propylene polymer is a propylene homopolymer or a copolymer of propylene and at least one comonomer selected from ethylene and C 4 -C 20 alpha-olefins, wherein the copolymer has a propylene content of at least 80 wt % and has a melting point of greater than 115° C., and wherein the hydrocarbon resin comprises an aliphatic hydrocarbon resin, a hydrogenated aliphatic hydrocarbon resin, an aromatic hydrocarbon resin, a hydrogenated aromatic hydrocarbon resin, a cycloaliphatic hydrocarbon resin, a hydrogenated cycloaliphatic hydrocarbon resin, a polyterpene resin, a terpene-phenol resin, a rosin ester resin, a rosin acid resin, or a combination thereof; and a second layer, B, wherein the second layer comprises a propylene-based elastomer, wherein the propylene-based elastomer comprises propylene and at least one comonomer selected from ethylene and C 4 -C 20 alpha-olefins, has a propylene content of at least 75 wt %, an mm triad tacticity of greater than 75%, a melting point of less than 115° C., and a heat of fusion of less than 65 J/g.

2 . The multilayer film of claim 1 , wherein the film further comprises a third layer, C, wherein the third layer comprises a propylene polymer wherein the propylene polymer is a propylene homopolymer or a copolymer of propylene and at least one comonomer selected from ethylene and C 4 -C 20 alpha-olefins, wherein the copolymer has a propylene content of at least 80 wt % and has a melting point of greater than 115° C.

3 . The multilayer film of claim 2 , wherein the film has the structure BAC.

4 . The multilayer film of claim 3 , wherein the propylene polymer of the C layer is substantially the same as the propylene polymer of the A layer.

5 . The multilayer film of claim 2 , wherein the film has the structure CBAB or CBABC.

6 . The multilayer film of claim 5 , wherein the propylene-based elastomers of the two B layers are substantially the same.

7 . The multilayer film of claim 5 , wherein the film has the structure CBABC.

8 . The multilayer film of claim 7 , wherein the propylene polymers of the two C layers are substantially the same.

9 . The multilayer film of claim 1 , wherein the B layer further comprises from 10 to 90 wt % of a propylene polymer, wherein the propylene polymer is a propylene homopolymer or a copolymer of propylene and at least one comonomer selected from ethylene and C 4 -C 20 alpha-olefins, wherein the copolymer has a propylene content of at least 80 wt % and has a melting point of greater than 115° C.

10 . The multilayer film of claim 1 , wherein the B layer further comprises a slip additive and/or antiblocking additive in an amount of from 0.01 to 10 wt % by the weight of the layer.

11 . The multilayer film of claim 1 , wherein the propylene-based elastomer has a propylene content of from 80 wt % to 97 wt %, and an ethylene content of from 3 wt % to 20 wt %.

12 . The multilayer film of claim 1 , wherein the propylene-based elastomer has a propylene content of from 90 wt % to 97 wt %, and an ethylene content of from 3 wt % to 10 wt %.

13 . The multilayer film of claim 1 , wherein the propylene polymer of each layer is independently selected from a propylene homopolymer or a random copolymer of propylene.

14 . The multilayer film of claim 1 , wherein the hydrocarbon resin has a total dicyclopentadiene, cyclopentadiene, and methylcyclopentadiene derived content of from about 60 wt % to about 100 wt % of the total weight of the hydrocarbon resin and wherein the hydrocarbon resin has a weight average molecular weight of from about 600 g/mole to about 1400 g/mole.

15 . The multilayer film of claim 1 , wherein the hydrocarbon resin is present in the A layer from about 5 wt % to about 30 wt % by weight of the A layer.

16 . The multilayer film of claim 1 , wherein the film is a cast film, a blown film, or a laminated film.

17 . The multilayer film of claim 1 , wherein the film is a cast film.

18 . The multilayer film of claim 1 , wherein the thickness of the A layer is from 30% to 70% of the total thickness of the multilayer film.

19 . The multilayer film of claim 1 , wherein the ratio of the thickness of A:B is (0.5-5):1.

20 . The multilayer film of claim 1 , wherein the film has a sealing initiation temperature of less than about 105° C., preferably less than about 80° C.

21 . The multilayer film of claim 1 , wherein the film has an Elmendorf TD tear strength, as determined according to ASTM D1922, of less than about 3.0 g/μm, and an 1% MD Secant Modulus, as determined according to the method of ASTM D882, of greater than 750 MPa.

22 . A multilayer film comprising:
a first layer, A, wherein the first layer comprises from 5 to 30 wt % of a hydrocarbon resin and from 70 to 95 wt % of a propylene polymer, wherein the propylene polymer is a propylene homopolymer or a copolymer of propylene and at least one comonomer selected from ethylene and C 4 -C 20 alpha-olefins, wherein the copolymer has a propylene content of at least 80 wt % and has a melting point of greater than 115° C., and wherein the hydrocarbon resin comprises an aliphatic hydrocarbon resin, a hydrogenated aliphatic hydrocarbon resin, an aromatic hydrocarbon resin, a hydrogenated aromatic hydrocarbon resin, a cycloaliphatic hydrocarbon resin, a hydrogenated cycloaliphatic hydrocarbon resin, a polyterpene resin, a terpene-phenol resin, a rosin ester resin, a rosin acid resin, or a combination thereof; and a second layer, B, wherein the second layer comprises a propylene-based elastomer comprising propylene and at least one comonomer selected from ethylene and C 4 -C 20 alpha-olefins, wherein the propylene-based elastomer has a propylene content of at least 90 wt %, an mm triad tacticity of greater than 75%, a melting point of less than 115° C., and a heat of fusion of less than 65 J/g; and a third layer, C, wherein the third layer comprises a propylene polymer, wherein the propylene polymer is a propylene homopolymer or a copolymer of propylene and at least one comonomer selected from ethylene and C 4 -C 20 alpha-olefins, wherein the copolymer has a propylene content of at least 80 wt % and has a melting point of greater than 115° C.; wherein the multilayer film has a BAC structure, and wherein the film has an Elmendorf TD tear strength, as determined according to ASTM D1922, of less than about 3.0 g/μm, and an 1% MD Secant Modulus, as determined according to ASTM D882, of greater than 750 MPa.

23 . The multilayer film of claim 22 , wherein the film has a sealing initiation temperature, of less than 105° C.

24 . A use of a blend of a propylene polymer and a hydrocarbon resin in a first layer of a multilayer film for reducing Elmendorf TD tear strength and/or increasing MD 1% secant modulus of the multilayer film as compared to the same film not comprising the hydrocarbon resin in the first layer,
wherein the blend comprises from 1 to 50 wt % of the hydrocarbon resin and from 50 to 99 wt % of the propylene polymer based on the weight of the blend, wherein the propylene polymer is a propylene homopolymer or a copolymer of propylene and at least one comonomer selected from ethylene and C 4 -C 20 alpha-olefins, wherein the copolymer has a propylene content of at least 80 wt % and h

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Cheng Lan Y
• Keung Jay K
• Lernoux Etienne R H
• Lui Nai-Tong

Classifications

• B32B27/12

  next to a fibrous or filamentary layer · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• B32B2307/50

  having particular mechanical properties · CPC title

• B32B27/00

  Layered products comprising {a layer of} synthetic resin {(fibrous or filamentary layer made of a synthetic resin B32B5/02; particulate layer made of a synthetic resin B32B5/16; foamed layer made of a synthetic resin B32B5/18)} · CPC title

• B32B2307/30

  having particular thermal properties · CPC title