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 70-95 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, wherein the polypropylene composition comprises a random propylene copolymer having a comonomer content from 0.2-5 wt. % based on the weight of the random propylene copolymer and 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, wherein the thermoplastic composition has a melt flow index of less than 0.3 g/10 min determined in accordance with ISO 1133 (2.16 kg, 230° C.), wherein the container has a shape formed by one or more walk having a wall thickness of thickness of 5 mm or less, wherein the shape is maintained after exposure to a temperature of 133° C. and a pressure of 1.6 bar for 3,000 hours; and wherein the container is a cooling fluid expansion reservoir in automotive applications.

2. The container of claim 1 wherein the polypropylene composition further comprises a propylene homopolymer.

3. The container of claim 2, wherein the propylene homopolymer has a melt flow index of at most 5 g/10 min determined in accordance with ISO 1133 (2.16 kg, 230° C.).

4. The container of claim 1 wherein the amount of random propylene copolymer is from 30-70 wt. % based on the weight of the polypropylene composition.

5. 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.

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

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

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 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.

10. The container of claim 1 wherein the thermoplastic composition has a heat deflection temperature (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.

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

12. The container of claim 11 wherein the adhesion promoter is a modified polyolefin comprising any one or more of acid anhydride groups or carboxylic acid groups.

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

14. The container of claim 1 herein the random propylene copolymer has a melt flow index of 0.15-0.25 g/10 min.

15. A method for the manufacture of the container of claim 1 comprising blow moulding or injection moulding the thermoplastic composition to form the container.

16. A container prepared from a thermoplastic composition comprising from 70-95 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, wherein the polypropylene composition comprises a random propylene copolymer having an ethylene content from 0.2-5 wt. % based on the weight of the random propylene copolymer and a melt flow index of at most 0.7 g/10 min determined in accordance with ISO 1133 (2.16 kg, 230° C.), from 5-15 wt. % based on the weight of the thermoplastic composition of glass fibres having a length of from 1-10 mm and a diameter of from 5-30 μm, from 0-3 wt. % based on the weight of the thermoplastic composition of additives wherein the thermoplastic composition has a melt flow index of less than 0.3 g/10 min determined in accordance with ISO 1133 (2.16 kg, 230° C.); wherein the container is a cooling fluid expansion reservoir in automotive applications.

17. An internal combustion engine, comprising: a cooling fluid expansion reservoir, wherein the cooling fluid expansion reservoir is prepared from a thermoplastic composition comprising from 70-95 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, wherein the polypropylene composition comprises a random propylene copolymer having a comonomer content from 0.2-5 wt. % based on the weight of the random propylene copolymer and 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, wherein the thermoplastic composition has a melt flow index of less than 0.3 g/10 min determined in accordance with ISO 1133 (2.16 kg, 230° C.).

Description

EXAMPLES

(1) 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.

(2) 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 μm diameter average fibre Binani 3B length 4 mm fibreglass

(3) 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

(4) 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.

(5) 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

(6) TC2=ethylene content in random propylene copolymer

(7) Tot. C2=total ethylene content in composition

(8) N/A=not measured.

(9) 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 (%)