Polypropylene blend with improved balance between sit and melting point

Patent metadata

Field	Value
Publication number	US-9896577-B2
Application number	US-201214353734-A
Country	US
Kind code	B2
Filing date	Oct 31, 2012
Priority date	Oct 31, 2011
Publication date	Feb 20, 2018
Grant date	Feb 20, 2018

Abstract

Polymer composite comprising propylene copolymer composition having a comonomer content in the range of 2.5 to 10 wt. -%, the comonomers are C 5 to C 12 α-olefins, and a low-crystalline polymer having a melting temperature of below 120° C.,
wherein further said polymer composite has (i) a melting temperature of at least 140° C., and (ii) a heat sealing initiation temperature (SIT) of not more than 110° C.

First claim

The invention claimed is:

1. Polymer composite comprising:
(a) a polypropylene (A) having a comonomer content of below 4.0 wt. %, the comonomers are C 5 to C 12 α-olefins,
(b) a propylene copolymer (B) having a comonomer content of 4.0 to 20.0 wt. %, the comonomers are C 5 to C 12 α-olefins, and
(c) a low-crystalline polymer (C) having a melting temperature in the range of 50 to 100 ° C. and a heat of fusion in the range of 10 to 50 J/g,
wherein further
(i) the weight ratio of the polypropylene (A) to the propylene copolymer (B) is in the range of 20/80 to 80/20,
(ii) the polymer composite comprises 5 to 50 wt. % based on the total amount of polymer composite of low-crystalline polymer (C),
(iii) the low-crystalline polymer (C) has a lower crystallinity than a mixture (M) of the polypropylene (A) and the propylene copolymer (B),
(iv) the low-crystalline polymer (C) is a propylene-ethylene copolymer comprising ethylene as comonomer,
(v) the polymer composite has a melting temperature in the range of 145 to 163° C., and
(vi) the polymer composite has a heat sealing initiation temperature (SIT) of not more than 110° C.

2. Polymer composite according to claim 1 , wherein the mixture (M) of the polypropylene (A) and the propylene copolymer (B) has:
a comonomer content of at least 2.5 wt. % the comonomers are C 5 to C 12 α-olefins.

3. Polymer composite according to claim 1 , wherein the mixture (M) of the polypropylene (A) and the propylene copolymer (B) has:
(a) a melt flow rate MFR 2 (230° C.) measured according to ISO 133 in the range of 1.0 to 50.0 g/10 min, and/or
(b) a xylene soluble content (XCS) determined at 23° C. according to ISO 6427 of below 15 wt. %.

4. Polymer composite comprising:
(a) propylene copolymer composition (P) having a comonomer content in the range of 2.5 to 10 wt. %, the comonomers are C 5 to C 12 α-olefins, and
(b) a low-crystalline polymer (C) having a melting temperature in the range of 50 to 100 ° C. and a heat of fusion in the range of 10 to 50 J/g the low-crystalline polymer (C) is a propylene-ethylene copolymer comprising ethylene as comonomer, and wherein further said polymer composite has,
(i) a melting temperature of at least 145° C.,
(ii) a heat sealing initiation temperature (SIT) of not more than 110° C., and
(iii) the polymer composite comprises 5 to 50 wt. % based on the total amount of polymer composite of low-crystalline polymer (C).

5. Polymer composite according to claim 4 , wherein the propylene copolymer composition (P) has:
(a) a polypropylene (A) having a comonomer content of below 4.0 wt. %, the comonomers are C 5 to 12 α-olefins, and
(b) a propylene copolymer (B) having a comonomer content of 4.0 to 20.0 wt. %, the comonomers are C 5 to C 12 α-olefins,
wherein further the weight ratio of the polypropylene (A) to the propylene copolymer (B) is in the range of 20/80 to 80/20.

6. Polymer composite according to claim 4 , wherein:
(a) propylene copolymer composition (P) comprises:
(a1) a polypropylene (A) having a comonomer content of below 4.0 wt. %, the comonomers are C 5 to C 12 α-olefins, and
(a2) a propylene copolymer (B) having a comonomer content of 4.0 to 20.0 wt. %, the comonomers are C 5 to C 12 α-olefins,

(b) the weight ratio of the polypropylene (A) to the propylene copolymer (B) is in the range of 20/80 to 80/20, and
(c) the low-crystalline polymer (C) has a lower crystallinity than a mixture (M) of the polypropylene (A) and the propylene copolymer (B).

7. Polymer composite according to claim 4 , wherein the propylene copolymer composition (P) has:
(a) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of 1.0 to 50.0 g/10 min, and/or
(b) a xylene soluble content (XCS) determined at 23° C. according to ISO 6427 of below 15 wt. %.

8. Polymer composite according to claim 1 , wherein the polymer composite has:
(a) a hot tack force of at least 3.0 N, and/or
(b) fulfills the equation (Ib)
Tm−SIT≧ 40° C.

wherein
SIT is the heat sealing initiation temperature (SIT) given in centigrade [° C.] of the polymer composite, and
Tm is the melting temperature given in centigrade [° C.] of the polymer composite.

9. Polymer composite according to claim 1 , wherein the polypropylene (A):
(a) is a propylene homopolymer, and/or
(b) has a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 of not more than 15.0 g/10 min, and/or
(c) has a xylene soluble content (XCS) of below 2.0 wt. %.

10. Polymer composite according to claim 1 , wherein the propylene copolymer (B):
(a) comprises 1-hexene as comonomer, and/or
(b) has a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 of more than 4 g/10min.

11. Polymer composite according to claim 1 , wherein the comonomer content of the low-crystalline polymer (C) is in the range of 7 to 20 wt. %.

12. Polymer composite according to claim 1 , wherein the low-crystalline polymer (C) has:
(a) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of 1 to 40 g/10 min, and/or
(b) a density of below 910 kg/m 3 .

13. Polymer composite according to claim 1 , being provided as a film.

14. Polymer composite according claim 1 , being provided as a coating for an extrusion coated substrate.

Assignees

• Borealis Ag

Inventors

• Reichelt Kristin
• Resconi Luigi

Classifications

• 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

• C09D123/14

  Copolymers of propene (C09D123/16 takes precedence) · CPC title

• C08L2205/02

  containing two or more polymers of the same C08L -group · CPC title

• C08L23/142 Primary

  at least partially crystalline copolymers of propene with other olefins · CPC title

• C08L23/10 Primary

  Homopolymers or copolymers of propene · CPC title