Fiber reinforced polypropylene compositions
The present invention is directed to granules comprising a fiber reinforced composition (C), said composition comprising a propylene polymer (PP), an elastomeric ethylene copolymer (E) and short fibers (SF). Further, the present invention is directed to an article comprising said fiber reinforced composition (C).
1. Granules comprising a fiber reinforced composition (C), comprising:
i) 20.0 to 70.0 wt. % of a propylene polymer (PP) having a melt flow rate MFR 2 (230° C., 2.16 kg) determined according to ISO 1133 in the range of 50 to 150 g/10 min,
ii) 2.0 to 12.0 wt. % of an elastomeric ethylene copolymer (E) being a copolymer of ethylene and a C 4- C 10 α-olefin,
iii) 0.1 to 5.0 wt. % of an adhesion promoter (AP), and
iv) 10.0 to 70.0 wt. % of short glass fibers (SF) having an average length of 1.0 to 10.0 mm, based on the overall weight of the fiber reinforced composition (C), and
wherein said fiber reinforced composition (C) fulfils in-equation (I)
w
(
P
P
)
w
(
E
)
>
2
.
0
,
(
I
)
wherein w(PP) is the weight fraction [in wt. %] of the propylene polymer (PP), based on the overall weight of the polypropylene composition (C), and w(E) is the weight fraction [in wt. %] of the elastomeric ethylene copolymer (E), based on the overall weight of the fiber reinforced composition (C), and
wherein the polypropylene composition (C) has a tensile modulus determined according to ISO 527 of at least 8000 MPa.
2. The granules according to claim 1 , wherein the fiber reinforced composition (C) fulfils in-equation (II):
w
(
S
F
)
w
(
E
)
>
3
.
3
,
(
II
)
wherein w(SF) is the weight fraction [in wt. %] of the short glass fibers (SF), based on the overall weight of the polypropylene composition (C), and w(E) is the weight fraction [in wt.-%] of the elastomeric ethylene copolymer (E), based on the overall weight of the fiber reinforced composition (C).
3. The granules according to claim 1 , wherein the fiber reinforced composition (C) has a melt flow rate MFR 2 (230° C., 2.16 kg) determined according to ISO 1133 below 100.0 g/10 min.
4. The granules according to claim 1 , wherein the adhesion promoter (AP) is a polar modified polypropylene (PM-PP) being a propylene homo- or copolymer grafted with maleic anhydride having a melt flow rate MFR (190° C., 2.16 kg) determined according to ISO 1133 of at least 50.0 g/10 min.
5. The granules according to claim 1 , wherein the elastomeric ethylene copolymer (E) has a melt flow rate MFR (190° C., 2.16 kg) determined according to ISO 1133 of at least 25.0g/10 min.
6. The granules according to claim 1 , wherein the elastomeric ethylene copolymer (E) has one or more of:
a) a comonomer content of 2.0 to 25.0 mol %, and
b) a density below 0.900 g/cm 3 .
7. The granules according to claim 1 , wherein the elastomeric ethylene copolymer (E) is a copolymer of ethylene and 1-octene.
8. The granules according to claim 1 , wherein the propylene polymer (PP) is a propylene homopolymer.
9. The granules according to claim 1 , wherein the propylene polymer (PP) is at least bimodal.
10. The granules according to claim 1 , wherein the propylene polymer (PP) comprises:
i) 10.0 to 35.0 wt. % of a first propylene polymer (PP1),
ii) 30.0 to 70.0 wt. % of a second propylene polymer (PP2), and
iii) 10.0 to 35.0 wt. % of a third propylene polymer (PP3),
based on the overall weight of the propylene polymer (PP), wherein said first propylene polymer (PP1), said second propylene polymer (PP2) and said third propylene polymer (PP3) have different melt flow rates MFR 2 (230° C., 2.16 kg) determined according to ISO 1133.
11. The granules according to claim 1 , wherein the short glass fibers (SF) have an average diameter of 8 to 20 μm.
12. The granules according to claim 1 , comprising at least 80.0 wt. % of the fiber reinforced polypropylene composition (C), based on the overall weight of the granules.
13. The granules according to claim 1 , wherein the polypropylene composition (C) has a tensile modulus determined according to ISO 527 of at least 10 000 MPa.
14. An article comprising the fiber reinforced polypropylene composition (C) according to claim 1 .