Heterophasic propylene copolymer with low extractables
View Patent ↗Heterophasic propylene copolymer comprising a propylene-C 4 to C 12 α-olefin copolymer as a matrix in which an ethylene-propylene rubber is dispersed, said heterophasic propylene copolymer has good mechanical properties and low extractables.
1. Heterophasic propylene copolymer (RAHECO) comprising
(i) a matrix (M) being a propylene-C 4 to C 12 α-olefin copolymer (C-PP), said propylene-C 4 to C 12 α-olefin copolymer (C-PP) comprises units derivable from
(i.1) propylene and
(i.2) at least one C 4 to C 12 α-olefin; and
(ii) an elastomeric propylene copolymer (EC) dispersed in said matrix (M), said elastomeric propylene copolymer (EC) comprises units derivable from
(ii.1) propylene and
(ii.2) ethylene and optionally at least one C 4 to C 12 α-olefin;
wherein said heterophasic propylene copolymer (RAHECO) has
(a) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of 2.5 to 200.0 g/10 min;
(b) a total comonomer content in the range of 12.0 to 35.0 wt.-%;
(c) a xylene cold soluble (XCS) fraction determined according to ISO 16152 (25° C.) in an amount of 10.0 to 40.0 wt.-%;
(d) a total comonomer content of the xylene soluble (XCS) fraction in the range of 50.0 to 90.0 wt.-%
wherein said heterophasic propylene copolymer (RAHECO) fulfills
(e) the in-equation (I)
C
2
(
total
)
Cx
(
total
)
>
1.0
(
I
)
wherein
C2(total) is the ethylene content [in wt.-%] of the heterophasic propylene copolymer (RAHECO);
Cx(total) is the C 4 to C 12 α-olefin content [in wt.-%] of the heterophasic propylene copolymer (RAHECO)
wherein said heterophasic propylene copolymer (RAHECO) comprises a xylene cold in-soluble (XCI) fraction, having one or more of:
(f) a total comonomer content [in wt.-%] based on the weight of the xylene cold in-soluble (XCI) fraction in the range of 3.0 to 12.0 wt.-%;
(g) an ethylene content [in wt.-%] based on the total weight of the xylene cold in-soluble (XCI) fraction in the range of 2.0 to 11.0 wt.-%;
(h) a C 4 to C 12 α-olefin content [in wt.-%] based on the total weight of the xylene cold in-soluble (XCI) fraction in the range of 0.5 to 6.0 wt.-%;
(i) fulfills the in-equation (II)
C
2
(
XCI
)
Cx
(
XCI
)
>
1.0
(
II
)
wherein
C2(XCI) is the ethylene content [in wt.-%] of the xylene cold in-soluble (XCI) fraction of the heterophasic propylene copolymer (RAHECO);
Cx(XCI) is the C 4 to C 12 α-olefin content [in wt.-%] of the xylene cold in-soluble (XCI) fraction of the heterophasic propylene copolymer (RAHECO); or combinations thereof.
2. Heterophasic propylene copolymer (RAHECO) according to claim 1 , wherein one or more of the following is fulfilled:
(a) the ethylene content of the total heterophasic propylene copolymer (RAHECO) is in the range of 12.0 to 33.0 wt.-%, based on the weight of the heterophasic propylene copolymer (RAHECO);
(b) the C 4 to C 12 α-olefin content of the total heterophasic propylene copolymer (RAHECO) is in the range of 0.5 to 6.0 wt.-%, based on the weight of the heterophasic propylene copolymer (RAHECO); or combinations thereof.
3. Heterophasic propylene copolymer (RAHECO) according to claim 1 , wherein one or more of the following is fulfilled:
(a) the propylene-C 4 to C 12 α-olefin copolymer (C-PP) is a propylene-1-hexene copolymer (C 6 -PP);
(b) the elastomeric propylene copolymer (EC) is an ethylene-propylene rubber (EPR); or a combination thereof.
4. Heterophasic propylene copolymer (RAHECO) according to claim 1 , wherein the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (RAHECO) has an intrinsic viscosity (IV) determined according to DIN ISO 1628/1 (in Decalin at 135° C.) of at least 1.2 dl/g.
5. Heterophasic propylene copolymer (RAHECO) according to claim 1 fulfilling one or more of:
(a) the in-equation (III)
C
(
XCS
)
C
(
total
)
≥
1.5
(
III
)
wherein
C(XCS) is the total comonomer content [in wt.-%] of the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (RAHECO);
C(total) is the total comonomer content [in wt.-%] of the total heterophasic propylene copolymer (RAHECO);
(b) the in-equation (IV)
C
2
(
XCS
)
C
2
(
total
)
≥
1.7
(
IV
)
wherein
C2(XCS) is the ethylene content [in wt.-%] of the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (RAHECO);
C2(total) is the ethylene content [in wt.-%] of the total heterophasic propylene copolymer (RAHECO);
(c) the in-equation (V)
C
2
(
XCS
)
C
(
XCI
)
≥
4.5
(
V
)
wherein
C2(XCS) is the ethylene content [in wt.-%] of the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (RAHECO);
C(XCI) is the total comonomer content [in wt.-%] of the xylene cold in-soluble (XCI) fraction of the heterophasic propylene copolymer (RAHECO);
(d) the in-equation (VI)
C
2
(
XCS
)
C
2
(
XCI
)
≥
5.0
(
VI
)
wherein
C2(XCS) is the ethylene content [in wt.-%] of the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (RAHECO);
C2(XCI) is the ethylene content [in wt.-%] of the xylene cold in-soluble (XCI) fraction of the heterophasic propylene copolymer (RAHECO); or combinations thereof.
6. Heterophasic propylene copolymer (RAHECO) according to claim 1 , wherein the propylene-C 4 to C 12 α-olefin copolymer (C-PP) comprises a first polypropylene fraction (PP1) and a second propylene-C 4 to C 12 α-olefin copolymer fraction (C-PP2).
7. Heterophasic propylene copolymer (RAHECO) according to claim 6 , wherein one or more of the following are fulfilled:
(a) the comonomer content [in wt-%] in the propylene-C 4 to C 12 α-olefin copolymer (C-PP) is higher than in the first polypropylene fraction (PP1);
(b) the comonomer content between the first polypropylene fraction (PP1) and the propylene-C 4 to C 12 α-olefin copolymer (C-PP) differ by at least 1.5 wt-%;
(c) the comonomer content between the first polypropylene fraction (PP1) and the second propylene-C 4 to C 12 α-olefin copolymer fraction (C-PP2) differ by at least 2.5 wt-%; or combinations thereof.
8. Heterophasic propylene copolymer (RAHECO) according to claim 6 , wherein the first polypropylene fraction (PP1) is
(a) a propylene homopolymer fraction (H-PP1);
or
(b) a first propylene-C 4 to C 12 α-olefin copolymer fraction (C-PP1).
9. Heterophasic propylene copolymer (RAHECO) according to claim 6 , wherein one or more of the following is fulfilled:
(a) the C 4 to C 12 α-olefin content in second propylene-C 4 to C 12 α-olefin copolymer fraction (C-PP2) is in the range of 2.0 to 15.0 wt.-%;
(b) the comonomer content in the propylene-C 4 to C 12 α-olefin copolymer (C-PP) is in the range of 1.5 to 9.0 wt.-%; or combinations thereof.
10. Heterophasic propylene copolymer (RAHECO) according to claim 1 , wherein the elastomeric propylene copolymer (EC) has a comonomer content in the range of 40 to 90 wt.-%.
11. Heterophasic propylene copolymer (RAHECO) according to claim 1 fulfilling in-equation (VIII)
C
(
total
)
XCS
≥
1.0
(
VIII
)
wherein
C(total) is the total comonomer content [in wt-%] of the heterophasic propylene copolymer (RAHECO);
XCS is the content [in wt. -%] of the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (RAHECO).
12. Heterophasic propylene copolymer (RAHECO) according to claim 1 having a first glass transition temperature Tg(1) and a second glass transition temperature Tg(2), wherein said first glass transition temperature Tg(1) is above the second glass transition temperature Tg(2).
13. Heterophasic propylene copolymer (RAHECO) according to claim 1 having one or more of the following:
(a) a first glass transition temperature Tg(1) in the range of −5 to +12° C.;
(b) a second glass transition temperature Tg(2) in the range of −45 to −25° C.; or combinations thereof.
14. Heterophasic propylene copolymer (RAHECO) according to claim 1 , wherein said heterophasic propylene copolymer (RAHECO) is α-nucleated.
15. Heterophasic propylene copolymer (RAHECO) according to claim 1 having
a tensile modulus measured according ISO 527-1 at 23° C. of at least 500 MPa.
16. A process for the preparation of a heterophasic propylene copolymer (RAHECO) comprising
(i) a matrix (M) being a propylene-C 4 to C 12 α-olefin copolymer (C-PP), said propylene-C 4 to C 12 α-olefin copolymer (C-PP) comprises units derivable from
(i.1) propylene and
(i.2) at least one C 4 to C 12 α-olefin; and
(ii) an elastomeric propylene copolymer (EC) dispersed in said matrix (M), said elastomeric propylene copolymer (EC) comprises units derivable from
(ii.1) propylene and
(ii.2) ethylene and optionally at least one C 4 to C 12 α-olefin;
wherein said heterophasic propylene copolymer (RAHECO) has
(a) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of 2.5 to 200.0 g/10 min;
(b) a total comonomer content in the range of 12.0 to 35.0 wt.-%;
(c) a xylene cold soluble (XCS) fraction determined according to ISO 16152 (25 ° C.) in an amount of 10.0 to 40.0 wt.-%;
(d) a total comonomer content of the xylene soluble (XCS) fraction in the range of 50.0 to 90.0 wt.-%;
wherein said heterophasic propylene copolymer (RAHECO) fulfills
(e) the in-equation (I)
C
2
(
total
)
Cx
(
total
)
>
1.0
(
I
)
wherein
C2(total) is the ethylene content [in wt.-%] of the heterophasic propylene copolymer (RAHECO);
Cx(total) is the C 4 to C 12 α-olefin content [in wt.-%] of the heterophasic propylene copolymer (RAHECO);
wherein said heterophasic propylene copolymer (RAHECO) comprises a xylene cold in-soluble (XCI) fraction, having one or more of:
(f) a total comonomer content [in wt.-%] based on the weight of the xylene cold in-soluble (XCI) fraction in the range of 3.0 to 12.0 wt.-%;
(g) an ethylene content [in wt.-%] based on the total weight of the xylene cold in-soluble (XCI) fraction in the range of 2.0 to 11.0 wt.-%;
(h) a C 4 to C 12 α-olefin content [in wt.-%] based on the total weight of the xylene cold in-soluble (XCI) fraction in the range of 0.5 to 6.0 wt.-%;
(i) fulfills the in-equation (II)
C
2
(
XCI
)
Cx
(
XCI
)
>
1.0
(
II
)
wherein
C2(XCI) is the ethylene content [in wt.-%] of the xylene cold in-soluble (XCI) fraction of the heterophasic propylene copolymer (RAHECO);
Cx(XCI) is the C 4 to C 12 α-olefin content [in wt.-%] of the xylene cold in-soluble (XCI) fraction of the heterophasic propylene copolymer (RAHECO); or combinations thereof;
the process comprising the steps of polymerizing:
(I) propylene and an C 4 to C 12 α-olefin so as to form the matrix (M) being the propylene-C 4 to C 12 α-olefin copolymer (C-PP); and subsequently polymerizing
(II) propylene; ethylene; and optionally at least one C 4 to C 12 α-olefin so as to form the elastomeric propylene copolymer (EC) dispersed in said matrix (M);
wherein both steps (I) and (II) take place in the presence of the same single site solid particulate catalyst, the catalyst comprising
(i) a complex of formula (I):
R n (Cp′) 2 MX 2 (I)
wherein
“M” is zirconium (Zr) or hafnium (Hf),
each “X” is independently a monovalent anionic σ-ligand,
each “Cp′ ” is a cyclopentadienyl-type organic ligand independently selected from the group consisting of substituted cyclopentadienyl, substituted indenyl, substituted tetrahydroindenyl, and substituted or unsubstituted fluorenyl, said organic ligands coordinate to the transition metal (M),
“R” is a bivalent bridging group linking said organic ligands (Cp'),
“n” is 1 or 2 and
(ii) a cocatalyst comprising a compound of a group 13 metal.
17. The process according to claim 16 , wherein step (I) comprises polymerizing propylene and optionally a C 4 to C 12 α-olefin so as to form the first polypropylene fraction (PP1) and subsequently polymerizing in another reactor propylene and C 4 to C 12 α-olefin so as to form the second propylene-C 4 to C 12 α-olefin copolymer fraction (C-PP2), the first polypropylene fraction (PP1) and the second propylene-C 4 to C 12 α-olefin copolymer fraction (C-PP2) form the propylene-C 4 to C 12 α-olefin copolymer (C-PP).
18. An article comprising the heterophasic propylene copolymer (RAHECO) according claim 1 , wherein the article is selected from the group consisting of a pouche, medical pouche, food packaging, film, bottle, and combinations thereof.