Soft and flexible polyolefin composition

Patent metadata

Field	Value
Publication number	US-10214640-B2
Application number	US-201515536052-A
Country	US
Kind code	B2
Filing date	Nov 17, 2015
Priority date	Dec 19, 2014
Publication date	Feb 26, 2019
Grant date	Feb 26, 2019

Abstract

The present disclosure provides a polyolefin composition made from or containing:
A) from about 63 to about 78% by weight of a copolymer of butene-1 with ethylene having a copolymerized ethylene content of up to about 18% by mole and no melting peak detectable at the DSC at the second heating scan; B) from about 22 to about 37% by weight of (i) a propylene homopolymer, or (ii) a propylene copolymer, or (iii) a mixture of two or more of (i) and (ii), having a melting temperature T m , measured by DSC at the second heating scan, of from about 130° C. to about 165° C.;

wherein (i) the amounts of A) and B) are referred to the total weight of A)+B) and (ii) having a melting enthalpy ΔH fus , measured by DSC at the second heating scan, of from 7 to 30 J/g.

First claim

What is claimed is:

1. A polyolefin composition comprising:
A) from about 63 to about 78% by weight, based upon the total weight of the polyolefin composition, of a copolymer of butene-1 with ethylene having a copolymerized ethylene content of up to about 18% by mole, based upon the molar composition of the copolymer, and no melting peak detectable at the DSC at the second heating scan and
B) from about 22 to about 37% by weight, based upon the total weight of the polyolefin composition, of (i) a propylene homopolymer, or (ii) a propylene copolymer, or (iii) a mixture of two or more of (i) and (ii), having a melting temperature T m , measured by DSC at the second heating scan, of from about 130° C. to about 165° C.,

wherein (i) the amounts of A) and B)=100 and referred to as the total weight of A)+B) and the DSC second heating scan is carried out with a heating rate of 10° C. per minute and (ii) having a melting enthalpy ΔH fus , measured by DSC at the second heating scan of from about 7 to about 30 J/g.

2. The polyolefin composition of claim 1 , wherein the composition has MIE from about 0.5 to about 8 g/10 min. and MIE is the melt flow index at 190° C. with a load of 2.16 kg, determined according to ISO 1133.

3. The polyolefin composition of claim 1 , wherein the composition has a flexural modulus equal to or lower than about 150 MPa.

4. The polyolefin composition of claim 1 , wherein the butene-1 copolymer component A) has Shore A equal to or lower than about 80.

5. The polyolefin composition of claim 1 , comprising:
i) from about 63 to about 69% by weight of A) and
ii) from about 31 to about 37% by weight of B).

6. The polyolefin composition of claim 1 , wherein the butene-1 copolymer component A) has at least one of the following additional features:
MIE of from about 0.5 to about 3 g/10 min.;
a lower limit of the copolymerized ethylene content of about 12% by mole, based upon the molar composition of the copolymer;
a Shore A value equal to or lower than about 80;
a Shore D value equal to or lower than about 20;
a Mw/Mn value, where Mw is the weight average molar mass and Mn is the number average molar mass, both measured by GPC, equal to or lower than about 3;
a tension set of less than about 30% at 100% of deformation at 23° C. (ISO 2285);
a percentage of butene-1 units in form of isotactic pentads (mmmm %) greater than about 80%;
tensile stress at break, measured according to ISO 527, of from about 3 MPa to about 20 MPa;
tensile elongation at break, measured according to ISO 527, of from about 550% to about 1000%;
intrinsic viscosity (I.V.) equal to or higher than about 1 dl/g;
crystallinity of less than about 30% measured via X-ray;
density of about 0.895 g/cm 3 or less;
content of xylene insoluble fraction at 0° C. of less than about 15% by weight, based upon the total weight of the copolymer.

7. The polyolefin composition of claim 1 , wherein the propylene homopolymer or copolymer component B) has MFRL values of from about 0.5 to about 9 g/10 min, where MFRL is the melt flow rate at 230° C. with a load of 2.16 kg, determined according to ISO 1133.

8. An article of manufacture comprising:
(1) a polyolefin composition comprising:
A) from about 63 to about 78% by weight, based upon the total weight of the polyolefin composition, of a copolymer of butene-1 with ethylene having a copolymerized ethylene content of up to about 18% by mole, based upon the molar composition of the copolymer, and no melting peak detectable at the DSC at the second heating scan and
B) from about 22 to about 37% by weight, based upon the total weight of the polyolefin composition, of (i) a propylene homopolymer, or (ii) a propylene copolymer, or (iii) a mixture of two or more of (i) and (ii), having a melting temperature T m , measured by DSC at the second heating scan, of from about 130° C. to about 165° C.,
wherein (i) the amounts of A) and B)=100 and referred to as the total weight of A)+B) and the DSC second heating scan is carried out with a heating rate of 10° C. per minute and (ii) having a melting enthalpy ΔH fus , measured by DSC at the second heating scan of from about 7 to about 30 J/g.

9. The article of manufacture according to claim 8 , wherein the article is a liner.

10. The article of manufacture according to claim 8 , wherein the article is a twist closure comprising a liner prepared from the polyolefin composition.

11. The article of manufacture according to claim 10 , wherein the twist is for a food container.

12. The article of manufacture according to claim 10 , wherein the twist is in the form of a cap.

13. A process for preparing a liner comprising the steps:
1) laying down a polyolefin composition in a molten state on the inner surface of a closure, wherein the polyolefin composition comprises
A) from about 63 to about 78% by weight, based upon the total weight of the polyolefin composition, of a copolymer of butene-1 with ethylene having a copolymerized ethylene content of up to about 18% by mole, based upon the molar composition of the copolymer, and no melting peak detectable at the DSC at the second heating scan and
B) from about 22 to about 37% by weight, based upon the total weight of the polyolefin composition, of (i) a propylene homopolymer, or (ii) a propylene copolymer, or (iii) a mixture of two or more of (i) and (ii), having a melting temperature T m , measured by DSC at the second heating scan, of from about 130° C. to about 165° C.,
wherein (i) the amounts of A) and B)=100 and referred to as the total weight of A)+B) and the DSC second heating scan is carried out with a heating rate of 10° C. per minute and (ii) having a melting enthalpy ΔH fus , measured by DSC at the second heating scan of from about 7 to about 30 J/g; and

2) forming the polyolefin composition into the liner.

Assignees

• Basell Poliolefine Italia Srl

Inventors

• Marchini Roberta
• Spataro Stefano
• Pasquali Stefano
• Musacchi Gianluca

Classifications

• B65D41/0435

  with separate sealing elements · CPC title

• C08F2500/18

  Bulk density · CPC title

• C08L23/20 Primary

  having four to nine carbon atoms · CPC title

• C08L23/22 Primary

  Copolymers of isobutene; Butyl rubber; Homopolymers or copolymers of other iso-olefins · CPC title

• C08L2205/02

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