Films and methods of making the same

Patent metadata

Field	Value
Publication number	US-11220092-B2
Application number	US-201816217218-A
Country	US
Kind code	B2
Filing date	Dec 12, 2018
Priority date	Jan 4, 2018
Publication date	Jan 11, 2022
Grant date	Jan 11, 2022

Abstract

Disclosed are films including polypropylene impact copolymers for tarpaulin applications which can provide a combination of desired properties.

First claim

What is claimed is:

1. A film comprising a coating layer comprising:
(a) from about 30 to about 50 wt % of a propylene-based elastomer, based on total weight of polymer in the coating layer, comprising at least about 60 wt % of propylene-derived units and about 3 to about 25 wt % of ethylene-derived units, based on the weight of the propylene-based elastomer, wherein the propylene-based elastomer has a heat of fusion of less than about 80 J/g;
(b) from about 30 to about 60 wt % of an impact copolymer (ICP), based on total weight of polymer in the coating layer, the ICP comprising a polypropylene homopolymer and within the range of from about 10 to about 45 wt % of a propylene copolymer based on the weight of the ICP, wherein the propylene copolymer comprises from about 7 to 30 wt % of ethylene and/or C 4 to C 10 α-olefin derived units and the remainder propylene-derived units based on the weight of the propylene copolymer, the ICP having a melt flow rate (MFR) (230° C./2.16 kg) within the range of from about 10 to about 50 g/10 min and an Elongation at Break of greater than 60%, wherein the ICP has a heat deflection temperature at 66 psi of about 85° C. to about 95° C.; and
(c) from about 1 to about 10 wt % of low density polyethylene (LDPE), based on total weight of polymer in the coating layer,
wherein the film has at least one of the following properties: (i) a processing neck-in ratio of at most about 28% at a die gap of 1 mm for a coating thickness of (50±10%) μm; (ii) a seal strength at a sealing temperature of 250° C. of at least about 5% higher when sealed with a substrate consisting essentially of a polypropylene homopolymer; (iii) a tensile at break of at least about 80% higher in the Machine Direction (MD) and of at least about 50% higher in the Transverse Direction (TD); (iv) an Elongation at break of at most about 20% higher in MD and of at most about 27% in TD; and (v) a puncture resistance of at least about 20% higher in force and of at least about 15% higher in energy at break, compared to that of a film comprising an alloy of polypropylene and rubber in place of the propylene-based elastomer and the impact copolymer but otherwise identical in terms of film formulation, thickness and structure.

2. The film of claim 1 , wherein the propylene-based elastomer has about 11 to about 16 wt % ethylene-derived units, based on the weight of the propylene-based elastomer.

3. The film of claim 1 , wherein the propylene-based elastomer has about 15 to about 16 wt % ethylene-derived units, based on the weight of the propylene-based elastomer.

4. The film of claim 1 , wherein the ICP has about 90 to about 91 wt % propylene-derived units, based on the weight of the ICP.

5. The film of claim 1 , wherein the ICP further has at least one of the following properties:
(i) a 1% Secant flexural modulus of about 130 to about 200 kpsi;
(ii) a tensile strength at yield of about 2800 to about 3000 psi; and
(iii) a notched Izod impact at 23° C. (ISO 180/A) of greater than about 40 kJ/m 2 .

6. The film of claim 1 , wherein the coating layer further comprises at least one of an anti-ultraviolet agent and a color masterbatch.

7. The film of claim 1 , further comprising a substrate consisting essentially of a polypropylene homopolymer.

8. The film of claim 7 , wherein the coating layer is coated to the substrate at a temperature of 250° C.

9. The film of claim 8 , wherein the film has a seal strength of at least about 5% higher than that of a film comprising an alloy of polypropylene and rubber in place of the propylene-based elastomer and the impact copolymer but otherwise identical in terms of film formulation, thickness and structure.

10. A tarpaulin comprising the film of claim 1 .

11. The film of claim 1 , wherein the propylene copolymer comprises from about 7 to 25 wt % ethylene and/or C 4 to C 10 α-olefin derived units and the remainder propylene-derived units based on the weight of the propylene copolymer.

12. The film of claim 1 , wherein the propylene copolymer comprises from about 7 to 20 wt % ethylene and/or C 4 to C 10 α-olefin derived units and the remainder propylene-derived units based on the weight of the propylene copolymer.

13. The film of claim 1 , wherein a total comonomer derived unit content of the ICP is within a range from 2 to 6 wt % by weight of the ICP.

14. The film of claim 1 , wherein the propylene copolymer has a molecular weight distribution (M w /M n ) within the the range from from 6 to 9.

15. The film of claim 1 , wherein the coating layer consists essentially of the propylene-based elastomer, the impact copolymer, and the LDPE.

16. The film of claim 1 , wherein the film has a seal strength at a sealing temperature of 250° C. of at least 5% higher when sealed with a substrate consisting essentially of a polypropylene homopolymer compared to that of a film comprising an alloy of polypropylene and rubber in place of the propylene-based elastomer and the impact copolymer but otherwise identical in terms of film formulation, thickness and structure.

17. A method for making a film comprising a coating layer, comprising the steps of:
(a) preparing a coating layer comprising:
(i) from about 30 to about 50 wt % of a propylene-based elastomer, based on total weight of polymer in the coating layer, comprising at least about 60 wt % of propylene-derived units and about 3 to about 25 wt % of ethylene-derived units, based on the weight of the propylene-based elastomer, wherein the propylene-based elastomer has a heat of fusion of less than about 80 J/g,
(ii) from about 30 to about 60 wt % of an impact copolymer (ICP), based on total weight of polymer in the coating layer, the ICP comprising a polypropylene homopolymer and within the range of from about 10 to about 45 wt % of a propylene copolymer based on the weight of the ICP, wherein the propylene copolymer comprises from about 7 to 30 wt % of ethylene and/or C 4 to C 10 α-olefin derived units and the remainder propylene-derived units based on the weight of the propylene copolymer, the ICP having a melt flow rate (MFR) (230° C./2.16 kg) within the range of from about 10 to about 50 g/10 min and an Elongation at Break of greater than 60%, wherein the ICP has a heat deflection temperature at 66 psi of about 85° C. to about 95° C., and
(iii) from about 1 to about 10 wt % of low density polyethylene (LDPE), based on total weight of polymer in the coating layer; and

(b) forming a film comprising the coating layer in step (a),
wherein the film has at least one of the following properties: (i) a processing neck-in ratio of at most about 28% at a die gap of 1 mm for a coating thickness of (50±10%)μm; (ii) a seal strength at a sealing temperature of 250° C. of at least about 5% higher when sealed with a substrate consisting essentially of a polypropylene homopolymer; (iii) a tensile at break of at least about 80% higher in the Machine Direction (MD) and of at least about 50% higher in the Transverse Direction (TD); (iv) an Elongation at break of at most about 20% higher in MD and of at most about 27% in TD; and (v) a puncture resistance of at least about 20% higher in force and of at least about 15% higher in energy at break, compared to that of a film comprising an alloy of polypropylene and rubber in place of the propylene-based elastomer and the impact copolymer but otherwise identical in terms of film formulation, thickness and structure.

18. The method of claim 17 , wherein the film in step (b) is formed by blown extrusion, cast extrusion, co-extrusion, blow molding, casting, or extrusion blow

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Abubakar Saifudin M
• Jin Jieyu
• Zhang Yinjie
• Gong Yanan

Classifications

• B32B25/10

  next to a fibrous or filamentary layer · CPC title

• B32B15/06

  of {natural rubber or synthetic} rubber · CPC title

• C08L2205/03

  containing three or more polymers in a blend · CPC title

• C08J2423/12

  Polypropene · CPC title

• C08J2423/06

  Polyethene · CPC title