EXPANSION RESERVOIR OF POLYPROPYLENE WITH GLASS FIBERS

Abstract

The present invention relates to a container, preferably a cooling fluid expansion reservoir prepared from a thermoplastic composition comprising from 95-70 wt. % based on the weight of the thermoplastic composition of a polypropylene composition having a total amount of comonomer of at most 3 wt. % based on the weight of the polypropylene composition and comprising a random propylene copolymer having a comonomer content from 0.2 to 5 wt. % based on the weight of the random propylene copolymer and the random propylene copolymer having a melt flow index of at most 0.7 g/10 min determined in accordance with ISO 1133 (2.16 kg, 230? C.), from 5-30 wt. % based on the weight of the thermoplastic composition of reinforcing fibres, from 0-5 wt. % based on the weight of the thermoplastic composition of additives.

Claims

1. A container prepared from a thermoplastic composition comprising from 95-70 wt. % based on the weight of the thermoplastic composition of a polypropylene composition having a total amount of comonomer of at most 3 wt. % based on the weight of the polypropylene composition and comprising a random propylene copolymer having a comonomer content from 0.2-5 wt % based on the weight of the random propylene copolymer and the random propylene copolymer having a melt flow index of at most 0.7 g/10 min determined in accordance with ISO 1133 (2.16 kg, 230? C.), from 5-30 wt. % based on the weight of the thermoplastic composition of reinforcing fibres, from 0-5 wt. % based on the weight of the thermoplastic composition of additives.

2. The container of claim 1 wherein the polypropylene composition further comprises a propylene homopolymer, preferably a propylene homopolymer having a melt flow index of at most 5 g/10 min determined in accordance with ISO 1133 (2.16 kg, 230? C.).

3. The container of claim 2 wherein the amount of random propylene copolymer is from 30-70 wt. % based on the weight of the polypropylene composition.

4. The container of claim 1 wherein the comonomer is selected from the group consisting of ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene and 4-methyl-1-pentene.

5. The container of claim 1 wherein the reinforcing fibres are selected from the group of glass fibres, metal fibres, mineral fibres, ceramic fibres, carbon fibres.

6. The container of claim 5 wherein the reinforcing fibres are glass fibres having a length of from 1-10 mm and a diameter of from 5-30 ?m.

7. The container of claim 1 wherein the thermoplastic composition has a melt flow index of at most 0.6 g/10 min as determined in accordance with ISO 1133 (2.16 kg, 230? C.).

8. The container of claim 1 wherein the thermoplastic composition has a tensile modulus as measured in accordance with ISO 527-1A at 23? C. of at least 2000 MPa and/or a stress at yield as measured according to ISO 527 at 23? C. of at least 45 MPa.

9. The container of claim 1 wherein the thermoplastic composition has a HDT as measured in accordance with ISO 75 at a load of 0.45 MPa of at least 135? C. and/or a HDT as measured in accordance with ISO 75 at a load of 1.8 MPa of at least 90? C.

10. The container of claim 1 wherein the additives comprise an adhesion promotor for promoting the adhesion between the reinforcing fibres and the polypropylene composition.

11. The container of claim 1 having a wall thickness of at most 5 mm.

12. The container of claim 1 wherein the container is a cooling fluid expansion reservoir in automotive applications.

13. A method for the manufacture of the container of claim 1 comprising blow moulding or injection moulding the thermoplastic composition as defined in claim 1.

14. An automotive cooling liquid expansion reservoir comprising the thermoplastic composition of claim 1.

15. The container of claim 8 wherein the thermoplastic composition has a tensile modulus as measured in accordance with ISO 527-1A at 23? of at least 2300 MPa and/or a stress at yield as measured according to ISO 527 at 23? C. of at least 50 MPa.

16. The container of claim 10 wherein the adhesion promotor is a modified polyolefin comprising any one or more of acid anhydride groups or carboxylic acid groups.

17. The container of claim 1 wherein the comonomer is ethylene.

Description

EXAMPLES

[0082] Polypropylene compositions as defined in tables 2 and 3 were prepared by blending the different ingredients listed in tables 2 and 3 using the ingredients mentioned in Table 1.

TABLE-US-00001 TABLE 1 Ingredient Description Supplier SABIC? PP 4935 Polypropylene random copolymer having a C.sub.2 SABIC monomer content of 1.5 wt. % and a MFI of 0.3 g/ 10 min (2.16 kg, 230? C.) SABIC? PP 528K Polypropylene homopolymer having a MFI of SABIC 3 g/10 min (2.16 kg, 230? C.) SABIC? PP 651H Polypropylene random copolymer having a C.sub.2 SABIC monomer content of 3.3 wt. % and a MFI of 0.25 g/10 min (2.16 kg, 230? C.) SABIC? PP 531 Ph Polypropylene homopolymer having a MFI of SABIC 0.23 g/10 min (2.16 kg, 230? C.) glass Glass fibres, 10 ?m diameter average fibre Binani 3B length 4 mm fibreglass

TABLE-US-00002 TABLE 2 polypropylene compositions CE1 Ex. 1 Ex. 2 Ex. 3 SABIC? PP 4935 100 93.6 88.6 83.6 glass 0 5 10 15 Additives 0 1.4 1.4 1.4 Total 100 100 100 100 Charpy Impact Notched 25.0 18.0 17.0 18.0 23? C. (kJ/m.sup.2) Charpy Impact Notched 85.0 24.0 17.0 14.0 23? C. after ageing in glycol/water (kJ/m.sup.2) Tensile modulus, 23? C. 1250 1740 2400 3050 (MPa) Tensile modulus, 80? C. 370 625 1150 1420 (MPa) Tensile modulus, 23? C. after 1175 1640 2200 2790 aging in glycol/water (MPa) MFI (dg/min) 0.3 0.24 0.21 0.14 Shrinkage, average after 1.90 1.41 1.23 1.17 24 hours at 23? C. (%) HDT L = 1.8 MPa (? C.) 56 69 96 107 HDT L = 0.45 MPa (? C.) 95 122 140 142 Tensile creep at 135? C., 5.8 N/A 1.0 N/A 2 MPa (%) Tensile creep at 135? C., max 11.5 2.2 0.88 3.3 MPa (%) elongation (30%) after 4 min

[0083] As can be seen from Table 2, compositions that may be used to prepare a container according to the invention (Examples Ex. 1, Ex. 2 and Ex. 3) show a good balance of impact and creep. Preferably, in the compositions of the invention, the amount of reinforcing fibres is in the range from 8-20 wt % based on the weight of the thermoplastic composition, as a higher amount of reinforcing fibres (Ex. 1 and Ex 2) leads to an increase in stiffness and/or creep resistance, but the impact decreases (compare example 3 (Ex. 3) to example 2 (Ex. 2)) when the amount of reinforcing fibres is higher.

[0084] As can be seen from Table 3 below, compositions that may be used to prepare a container according to the invention show a good balance of impact and creep.

Legend to the Tables

[0085] TC2=ethylene content in random propylene copolymer
Tot. C2=total ethylene content in composition
N/A=not measured.

TABLE-US-00003 TABLE 3 polypropylene compositions Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 TC2 (wt %) 1.5 3.3 3.3 3.3 3.3 Tot. C2 (wt %) 1.5 1.5 2.2 2.2 3.3 SABIC? PP 4935 88.6 0 0 0 0 SABIC? PP 528K 0 0 30 0 0 SABIC? PP 531Ph 0 47.7 0 30 0 SABIC? PP 651H 0 40.9 58.6 58.6 88.6 glass 10 10 10 10 10 Additives 1.4 1.4 1.4 1.4 1.4 Total 100 100 100 100 100 Charpy Impact Notched 17.0 17.0 17.0 18.0 20.0 23? C. (kJ/m.sup.2) Charpy Impact Notched 17.0 18.0 20.0 18.0 25.0 23? C. after ageing in glycol/water (kJ/m.sup.2) Tensile modulus, 23? C. 2400 2550 2425 2380 2000 (MPa) Tensile modulus, 80? C. 1150 1080 1100 925 840 (MPa) Tensile modulus, 23? C. 2200 2520 2300 2330 1890 after aging in glycol/water (MPa) MFI (dg/min) 0.21 0.16 0.26 0.15 0.13 Shrinkage, average after 1.23 1.30 1.17 1.28 1.25 24 hours at 23? C. (%) HDT L = 1.8 MPa (? C.) 96 90 97 86 84 HDT L = 0.45 MPa 140 140 138 136 127 (? C.) Tensile creep at 135? C., 1.0 N/A N/A N/A N/A 2 MPa (%) Tensile creep at 135? C., 2.2 2.0 1.7 3.0 N/A 3.3 MPa (%)