METHOD FOR TRANSPORTING PELLETS, METHOD FOR MANUFACTURING PELLETS, AND METHOD FOR THE MANUFACTURE OF A MODULDED PRODUCT FROM PELLETS

Abstract

Method for transporting pellets of a glass fibre reinforced thermoplastic polymer composition from a loading position to an unloading position, said pellets comprising a core and a thermoplastic polymer sheath surrounding said core, wherein the core comprises glass fibres extending in a longitudinal direction of the pellets and an impregnating agent, the method comprising loading pellets onto a non-vibrating belt conveyor at said loading position, conveying the pellets by means of said non-vibrating belt convey—or to said unloading position and unloading the pellets from said non-vibrating belt conveyor at said unloading position. Further methods are claimed as regards a process for manufacturing pellets of a glass fibre reinforced thermoplastic polymer composition and a process for the manufacture at a moulding position of a moulded product from pellets of a glass fibre reinforced thermoplastic polymer composition.

Claims

1. A method for transporting pellets of a glass fibre reinforced thermoplastic polymer composition from a loading position to an unloading position, said pellets comprising a core and a thermoplastic polymer sheath surrounding said core, wherein the core comprises glass fibres extending in a longitudinal direction of the pellets and an impregnating agent, the method comprising loading pellets onto a non-vibrating belt conveyor at said loading position, conveying the pellets by means of said non-vibrating belt conveyor to said unloading position and unloading the pellets from said non-vibrating belt conveyor at said unloading position.

2. The method of claim 1 wherein the thermoplastic polymer of the thermoplastic polymer sheath is polypropylene and the amount of glass fibre in the pellets is from 20 to 60 wt. % on the basis of the weight of the pellets.

3. The method of claim 1 wherein the non-vibrating belt conveyor comprises an endless flexible belt having two longitudinal outer edges perpendicular to a transport direction and wherein during the transport, the outer edges are folded towards each other so as to form a tube-like structure, said tube like structure containing the pellets.

4. The method according to claim 1 wherein the non-vibrating belt conveyor is cleaned continuously while moving away from the unloading position.

5. The method according to claim 1 wherein the method is a continuous method wherein pellets are continuously loaded to the non-vibrating belt conveyor at said loading position and continuously unloaded at said unloading position.

6. A process for manufacturing a glass fibre reinforced thermoplastic polymer composition comprising the steps of i) providing at least one continuous glass multifibre strand ii) applying a thermoplastic polymer sheath around said at least one continuous glass multifibre strand, iii) cutting the sheathed continuous glass multifibre strand into pellets at a cutting position, iv) transporting the pellets with the method of claim 1, v) filling a transport container with said pellets at a filling position.

7. The process of claim 6 wherein the transporting of the pellets in step iv) carried out over at least 50% of the distance between the cutting position and the filling position.

8. The process of claim 6 wherein the transporting of pellets between the cutting position and the filling position does not involve pneumatic conveying of the pellets using a piping system.

9. A process for the manufacture at a moulding position of a moulded product from pellets of a glass fibre reinforced thermoplastic polymer composition, said pellets comprising a core and a thermoplastic polymer sheath surrounding said core, wherein the core comprises glass fibres extending in a longitudinal direction of the pellets and an impregnating agent, the process comprising transporting of the pellets to the moulding position at least in part with the method of claim 1 and moulding of the pellets into the moulded product.

10. (canceled)

11. The process of claim 9 wherein the non-vibrating belt conveyor is a flexible belt having two longitudinal outer edges perpendicular to a transport direction which outer edges may be or are folded towards each other during the transport so as to form a tube-like structure, said tube like structure containing the pellets.

12. The process of claim 11 wherein the non-vibrating belt conveyor is an endless belt conveyor.

13. The process of claim 7 wherein the transporting of the pellets in step iv) carried out over at least 75% of the distance between the cutting position and the filling position.

Description

EXEMPLARY EMBODIMENT

[0047] Pellets of a glass fibre reinforced polypropylene composition are prepared using the method as disclosed in WO 2009/080281. To that extent several glass multifibre strands are fed in parallel to an applicator for application of approximately 10 wt. % of an impregnating agent. After application of the impregnating agent each of the strands is wire-coated (or sheathed) with a sheath of a polypropylene composition. The sheathed strands are then cooled in a water bath and fed to a cutting device where they are cut into pellets of 12 mm in length. Next the pellets are loaded onto a belt conveyor of the type SICON available from Continental contitech and transported over a length of about 150 meter to a warehouse where the pellets are unloaded from the belt conveyor into a filling silo. The belt conveyor comprises a rubber belt with a width of about 650 mm in open position and a width of about 250 mm in closed (tube-like) position. Next, octabins are filled with pellets from the filling silo and the octabins are then ready for shipment to end users.