Process for manufacturing of a fibre-reinforced polymer composition

Abstract

Process for producing a fibre-reinforced polymer composition comprising the following steps: a) providing a polymer composition, b) melting the polymer composition in a compounding device, c) feeding a non-woven fabric into the compounding device in the presence of the molten polymer composition, and d) withdrawing the fibre-reinforced polymer composition from the compounding device. Furthermore, the product obtained by the process and the use of a non-woven fabric in an extruder to reinforce a polymer with fibres are disclosed.

Claims

1. A process for producing a fibre-reinforced polymer composition comprising the following steps: a) providing a polymer composition (A); b) melting the polymer composition (A) in a compounding device; c) feeding a non-woven fabric into the compounding device in the presence of the molten polymer composition (A), wherein the non-woven fabric comprises at least 75 wt. % carbon fibres based on the total weight of the non-woven fabric; and d) withdrawing the fibre-reinforced polymer composition from the compounding device.

2. The process according to claim 1, wherein the compounding device is an extruder.

3. The process according to claim 1, wherein the non-woven fabric is fed into the compounding device through a side feed port.

4. The process according to claim 1, wherein the non-woven fabric further comprises glass reinforcing fibres.

5. The process according to claim 1, wherein the non-woven fabric is in the form of a stripe.

6. The process according to claim 5, wherein the stripe has a width of 10 to 300 mm.

7. The process according to claim 5, wherein the stripe has a length of at least 50 cm.

8. The process according to claim 1, wherein the average weight of the non-woven fabric is within the range of 100 to 1000 g/m.sup.2.

9. The process according to claim 1, wherein the polymer composition (A) comprises a polyolefin.

10. The process according to claim 9, wherein the content of the polyolefin is at least 50 wt. % based on the polymer composition (A).

11. The process according to claim 9, wherein the polymer composition (A) comprises a polypropylene.

12. The process according to claim 1, wherein a compatibilizer is added prior to step c).

13. The process according to claim 1, wherein the non-woven fabric is obtained by needle-punching.

Description

EXAMPLES

(1) In all examples a co-rotational twin-screw extruder (ZSK 40 from Coperion) has been used. As side-feeder a Coperion ZSB40 twin screw side feeder has been used.

(2) The following process parameters were used: throughput of 100 kg/h screw speed of 100-150 rpm barrel temperatures of 250 C. flat die plate with 5 mm holes, whereby 3 holes were opened

(3) Non-Woven Fabric:

(4) The non-woven fabric comprises 80 wt. % of carbon fibres and has been produced by needle-punching. The average fiber diameter is 7 m.

(5) The polymer and the additives different from the non-woven fabric are fed to the extruder and melt-kneaded in the 4.sup.th barrel of the extruder which consists of three kneading blocks (two times a KB 45/5/40, followed by a KB 45/5/20 LH) and a left-handed conveying element. The non-woven fabric is added in the 6.sup.th barrel using a side feeder. A second kneading zone located in the 8.sup.th barrel and consisting of three kneading blocks (KB 45/5/20) is used to distribute the carbon fibres homogeneously.

(6) Moreover, two TME elements (one TME 22.5/20 and one TME 22.5/20 LH) located between the 8.sup.th and the 9.sup.th barrel are used to further distribute the carbon fibres.

(7) The following compositions have been prepared.

(8) TABLE-US-00001 CE1 IE1 CF laid web [wt %] 20.0 CF non-woven fabric [wt %] 20.0 HF955MO.sup.1) [wt %] 64.85 63.5 Engage 8100.sup.2) [wt %] 10.0 10.0 SCONA TSPP 3598 [wt %] 5.0 5.0 GB.sup.3) Kinox-B15.sup.4) [wt %] 0.15 0.15 CF content [wt %] 20.35 19.82 Tensile modulus [MPa] 11279 10901 Tensile strength [MPa] 107.7 110.9 Impact strength [kJ/m.sup.2] 31.58 31.33 unnotched Impact strength notched [kJ/m.sup.2] 6.53 6.55 .sup.1)a propylene homopolymer distributed by Borealis having a density of 905 kg/m.sup.3, a melt flow rate (230 C., 2.16 kg, ISO 1133) of 20 g/10 min and a melting temperature of 167 C.; .sup.2)an ethylene-octene copolymer distributed by The Dow Chemical Company having a density of 870 kg/m.sup.3 and a melt flow rate (190 C., 2.16 kg, ISO 1133) of 1.0 g/10 min; .sup.3)compatibilizer distributed by BYK; .sup.4)additive package distributed by High Polymer Labs

(9) In comparative example 1 the laid web was fed manually to the compounding device whereby the initially targeted fibre content was 15 wt. % which, however, could not be reached by manual feeding. Hence, for comparison purposes a composition comprising the same amount of fibres but using the non-woven fabric according to the invention has been produced using the side-feeder. The physical properties of CE1 and IE1 are similar. However, manual feeding as required in CE1 is not feasible in an industrial-scale process. Moreover, it has not been possible to reach the desired final carbon fibre content using manual feed. Using the process of the invention the desired fibre content in the final composition can be easily adjusted by adjusting the feed speed of the side feeder.