Polypropylene based composition with improved paintability
The present invention relates to a polypropylene based composition comprising: (A) from 40.0 to 85.0 wt % of a heterophasic propylene copolymer having a content of xylene cold soluble (XCS) fraction in the range of 15 wt % to 35 wt %, based on the total weight of the heterophasic propylene copolymer; (B) from 5.0 to 15.0 wt % of a random copolymer of propylene with comonomer units selected from ethylene and alpha-olefins having from 4 to 12 carbon atoms which has been polymerized in the presence of a single-site catalyst system and has a melting temperature Tm as measured in differential scanning calorimetry (DSC) of less than 140° C.; (C) from 5.0 to 25.0 wt % of an ethylene copolymer with alpha-olefin comonomer units having from 4 to 12 carbon atoms with a density of from 850 kg/m 3 to 900 kg/m 3 ; and (D) from 5.0 to 25.0 wt % of an inorganic filler, wherein the amounts of components (A), (B), (C), and (D) are all based on the total weight amount of the polypropylene based composition, said polypropylene based composition having a melt flow rate (MFR2) as measured at 230° C. and 2.16 kg load in accordance with ISO 1133 in the range of 2.0 g/10 min to 20.0 g/10 min, an article comprising said polypropylene based composition and the use of said copolymer (B) for reducing the paint adhesion failure of an article comprising said polypropylene based composition.
1. A polypropylene based composition comprising:
(A) an amount from 40.0 to 85.0 wt % of a heterophasic propylene copolymer having a content of xylene cold soluble (XCS) fraction in a range of 15 wt % to 35 wt %, based on a total weight of the heterophasic propylene copolymer;
(B) an amount from 5.0 to 15.0 wt % of a random copolymer of propylene with comonomer units selected from the group consisting of ethylene and alpha-olefins having from 4 to 12 carbon atoms which has been polymerized in the presence of a single-site catalyst system and has a melting temperature Tm as measured in differential scanning calorimetry (DSC) of less than 140° C.;
(C) an amount from 5.0 to 25.0 wt % of an ethylene copolymer with alpha-olefin comonomer units having from 4 to 12 carbon atoms with a density of from 850 kg/m 3 to 900 kg/m 3− ; and
(D) an amount from 5.0 to 25.0 wt % of an inorganic filler,
wherein the amounts of components (A), (B), (C), and (D) are all based on a total weight of the polypropylene based composition,
said polypropylene based composition having a melt flow rate (MFR 2 ) as measured at 230° C. and 2.16 kg load in accordance with ISO 1133 in a range of 2.0 g/10 min to 20.0 g/10 min.
2. The polypropylene based composition according to claim 1 , wherein the xylene cold solubles (XCS) fraction of the heterophasic propylene copolymer (A) has a comonomer content of from 25 to 55 wt %, based on a total weight of the xylene cold solubles (XCS) fraction of the heterophasic propylene copolymer (A).
3. The polypropylene based composition according to claim 1 , wherein the heterophasic propylene copolymer (A) has a matrix phase and an elastomeric phase dispersed therein and the matrix phase is a random copolymer of propylene and comonomer units selected from the group consisting of ethylene and alpha olefins having from 4 to 12 carbon atoms, in an amount of from 0.01 wt % to 1.5 wt %, based on a total weight of the matrix phase of the heterophasic propylene copolymer (A).
4. The polypropylene based composition according to claim 1 , wherein the random copolymer of propylene with comonomer units selected from the group consisting of ethylene and alpha-olefins having from 4 to 12 carbon atoms (B) has a melt flow rate MFR (190° C., 2.16 kg) of from 0.8 g/10 min to 50.0 g/10 min.
5. The polypropylene based composition according to claim 1 , wherein the random copolymer of propylene with comonomer units selected from the group consisting of ethylene and alpha-olefins having from 4 to 12 carbon atoms (B) has an amount of a xylene cold soluble (XCS) fraction of less than 7.5 wt %, based on a total weight of the copolymer of propylene with comonomer units selected from the group consisting of ethylene and alpha-olefins having from 4 to 12 carbon atoms (B).
6. The polypropylene based composition according to claim 1 , wherein the random copolymer of propylene with comonomer units selected from the group consisting of ethylene and alpha-olefins having from 4 to 12 carbon atoms (B) has a crystallization temperature Tc of at least 85° C.
7. The polypropylene based composition according to claim 1 , wherein the random copolymer of propylene with comonomer units selected from the group consisting of ethylene and alpha-olefins having from 4 to 12 carbon atoms (B) has an amount of comonomer units of from 1.0 to 4.5 wt %, based on a total weight amount of monomer units in the random copolymer of propylene with comonomer units selected from the group consisting of ethylene and alpha-olefins having from 4 to 12 carbon atoms (B).
8. The polypropylene based composition according to claim 1 , wherein the ethylene copolymer with alpha-olefin comonomer units (C) is an ethylene based plastomer with comonomer units selected from the group consisting of alpha-olefins having from 4 to 12 carbon atoms.
9. The polypropylene based composition according to claim 1 , wherein the inorganic filler (D) is selected from the group consisting of talc, wollastonite, caolin and mica.
10. The polypropylene based composition according to claim 1 , wherein the polypropylene based composition has a Charpy notched impact strength at 23° C. of at least 50 KJ/m 2 and/or a Charpy notched impact strength at −20° C. of at least 5.0 KJ/m 2 .
11. The polypropylene based composition according to claim 1 , wherein the polypropylene based composition has a flexural modulus of at least 1300 MPa.
12. A painted article comprising the polypropylene based composition according to claim 1 .
13. The painted article according to claim 12 , wherein the painted article has a shrinkage of less than 1.0%.
14. The painted article according to claim 12 , wherein the painted article has a paint adhesion failure as average delaminated area of from 10.0 mm 2 to 50.0 mm 2 .