Fiber reinforced polypropylene composite
The present invention relates to a new composite comprising glass or carbon fibers and polymer-based fibers as well as to a process for the preparation of the composite and molded articles made from said composite.
1. Composite comprising:
a) 50 to 91.0 wt %, based on the total weight of the composite, of a polypropylene base material having a melt flow rate MFR 2 (230° C., 2.16 kg) measured according to ISO 1133 in the range of from 3.0 to 140.0 g/10 min, wherein the polypropylene base material is
i) a heterophasic propylene copolymer (HECO) comprising a semicrystalline polypropylene (PP) as a matrix in which an elastomeric propylene copolymer (EC) is dispersed or
ii) a propylene homopolymer (hPP); and
b) 8.6 to 45.0 wt %, based on the total weight of the composite, of a glass fiber (GF) or carbon fiber (CF); and
c) 2.5 to 20 wt %, based on the total weight of the composite, of a polymer-based fiber (PF) having a melting temperature of ≥210° C., wherein the polymer-based fiber (PF) also has a fiber average diameter in the range of 5 to 30 μm, a tenacity of from 3.0 cN/dtex, or both; and
d) 0.1 to 7.0 wt %, based on the total weight of the composite, of an adhesion promoter (AP), where the adhesion promoter is a maleic anhydride functionalized polypropylene,
wherein the weight ratio of the glass fiber (GF) or carbon fiber (CF) to the polymer-based fiber (PF) [(GF) or (CF)/(PF)] is at least 2:1.
2. Composite according to claim 1 , wherein the heterophasic propylene copolymer (HECO) has
a) a melt flow rate MFR 2 (230° C., 2.16 kg) in the range of from 5.0 to 120.0 g/10 min, and/or
b) a xylene cold soluble (XCS) fraction (25° C.) of from 15.0 to 50.0 wt %, based on the total weight of the heterophasic propylene copolymer (HECO), and/or
c) a comonomer content of ≤30.0 mol %, based on the heterophasic propylene copolymer (HECO).
3. Composite according to claim 1 , wherein an amorphous fraction (AM) of the heterophasic propylene copolymer (HECO) has
a) a comonomer content in the range of 30.0 to 60.0 mol %, based on the amorphous fraction (AM) of the heterophasic propylene copolymer (HECO), and/or
b) an intrinsic viscosity (IV) in the range of 1.8 to 4.0 dl/g.
4. Composite according to claim 1 , wherein the propylene homopolymer (hPP) has:
a) a melt flow rate MFR 2 (230° C., 2.16 kg) in the range of from 5.0 to 120.0 g/10 min, and/or
b) a melting temperature measured according to ISO 11357-3 of at least 150° C., and/or
c) a xylene cold soluble (XCS) content based on the total weight of the propylene homopolymer (hPP).
5. Composite according to claim 1 , wherein the glass fiber (GF) or carbon fiber (CF) has a fiber average diameter in the range of 5 to 30 μm and/or an average fiber length from 0.1 to 20 mm.
6. Composite according to claim 1 , wherein the glass fiber (GF) or carbon fiber (CF) comprises a sizing agent.
7. Composite according to claim 1 , wherein the polymer-based fiber (PF) is selected from the group consisting of a poly vinyl alcohol (PVA) fiber, a polyethylene terephthalate (PET) fiber, a polyamide (PA) fiber and mixtures thereof.
8. Composite according to claim 1 , wherein the polymer-based fiber (PF) also has
an average fiber length of 0.1 to 20 mm.
9. Composite according to claim 1 , wherein the melting temperature Tm according to ISO 11357-3 of the polymer-based fiber (PF) is ≥40° C. above the melting temperature Tm according to ISO 11357-3 of the polypropylene base material.
10. Molded article comprising the composite according to claim 1 .
11. Molded article according to claim 10 , wherein the molded article is an automotive article.