Chafe layer for a fluid conduit, fluid conduit, method for producing a fluid conduit and use of a polyurethane as a chafe layer and use of an ethylene copolymer as an additive

Abstract

A chafe layer for a fluid conduit, wherein the chafe layer consists of thermoplastic polyurethane which contains a polyol, in particular a short-chained, diol as a chain extender and isocyanate. The polyol is a polycarbonate. A fluid conduit, a method for producing a fluid conduit as well as the use of a polyurethane and the use of an ethylene copolymer as an additive.

Claims

1-10. (canceled)

11. A fluid conduit having a base body and a chafe layer, wherein the base body has at least one layer made of plastic, and the chafe layer forms an outer layer of the fluid conduit, wherein the chafe layer has a layer thickness of at least 0.1 mm to at most 1.0 mm and consists of thermoplastic polyurethane comprising polyol present as pol-ycarbonate polyol, diol as a chain extender and isocyanate.

12. The fluid conduit according to claim 1, wherein the isocyanate is a diphenyl methane-4,4′-diisocyanate.

13. The fluid conduit according to claim 1, wherein the thermoplastic polyurethane additionally contains at least one of the following substances as an additive: a lubricant, a wax, a phenolic antioxidant, an aminic antioxidant, a thioester-based antioxidant, a phosphite, a UV absorber, in particular based on benzotriazole or triazine, a sterically hindered amine, a hydrolysis inhibitor, in particular a carbodiimide, an antistatic agent, a flame retardant and an ethylene copolymer as abrasion improver.

14. The fluid conduit according to claim 13, wherein the additive has a proportion of at least 0.05% by weight and/or at most 10% by weight.

15. A method for producing the fluid conduit according to claim 1, wherein the fluid conduit has a chafe layer which is applied to a base body of the fluid conduit which has at least one layer made of plastic, so that the chafe layer forms an outer layer of the fluid conduit.

16. The method according to claim 15, wherein the method comprises the following method steps: a) providing the base body of the fluid conduit; b) applying the chafe layer to the base body by extrusion of an extrusion mixture; wherein the extrusion mixture contains the thermoplastic polyurethane as a polymeric mixture component.

17. The method according to claim 16, wherein the extrusion mixture comprises an ethylene copolymer as an additive as a further mixture component.

18. Use of a thermoplastic polyurethane which contains a polyol present as a polycarbonate polyol, in particular short-chained, diol as a chain extender and isocyanate, as a chafe layer with a layer thickness of at least 0.1 mm to at most 1.0 mm forming an outer layer of a fluid conduit and applied on a base body of the fluid conduit having at least one layer made of plastic.

19. Use of an ethylene copolymer as an additive, preferably as an abrasion improver, in a polyurethane in an outer layer of the fluid conduit applied to a base body of a fluid conduit having at least one layer made of plastic, in particular of an engine or a drive device comprising the engine, with a layer thickness of at least 0.1 mm to at most 1.0 mm.

Description

[0095] FIG. 1 shows a schematic sectional representation through a fluid conduit,

[0096] FIG. 2 shows a schematic longitudinal sectional representation through the fluid conduit in a first embodiment,

[0097] FIG. 3 shows a schematic longitudinal sectional representation of the fluid conduit in a second embodiment, and

[0098] FIG. 4 shows a schematic longitudinal sectional representation of the fluid conduit in a third embodiment.

[0099] FIG. 1 shows a schematic representation of a fluid conduit 1 which consists of a multi-layer composite 2. To form a fluid flow space 3 of fluid conduit 1, multi-layer composite 2 completely surrounds a longitudinal central axis 4 of fluid conduit 1 in the circumferential direction. In cross section, multi-layer composite 2 consists of a first layer 5, a second layer 6, a third layer 7 and a fourth layer 8. Layers 5, 6, 7 and 8 form a base body of fluid conduit 1. A chafe layer has been applied to base body 9. Each of the layers 5, 6, 7 and 8 is continuous in the circumferential direction and preferably has a constant wall thickness in the circumferential direction. This can also apply to the chafe layer 9 as well.

[0100] In the exemplary embodiment illustrated here, first layer 5 consists of a fluoropolymer, second layer 6 consists of a polyamide, third layer 7 consists of an ethylene-vinyl alcohol copolymer, and fourth layer 8 in turn consists of a polyamide. Basically, the wall thicknesses of layers 5, 6, 7 and 8 shown here can be identical. The wall thicknesses of layers 5, 6, 7 and 8 preferably increase in the radial direction outwards, starting from first layer 5, at least for some of the successive layers. In the exemplary embodiment shown here, chafe layer 9 consists of thermoplastic polyurethane, to which additives could have been added. Also, it has been applied to the base body by extrusion. This results in a particularly simple production of fluid conduit 1 and a reliable hold of chafe layer 9 on the base body.

[0101] The thermoplastic polyurathene comprises at least polyol, preferably short-chained diol as a chain extender and isocyanate, the polyol being a polycarbonatepolyol. In addition, an additive has been admixed to the polyurethane. 1,4-Butanediol is preferably used as the chain extender. The additive is, for example, an ethylene copolymer, particularly preferably a maleic anhydride-modified eth-ylene copolymer. In terms of quantity, the polyol and the isocyanate form the main components of the polyurethane. For example, the polyurethane consists of at least 80% by weight, at least 90% or at least 95% from these substances. The remainder is made up of the at least one additive and inevitable impurities. The additive is present in a proportion of at least 0.1% by weight and at most 3% by weight or at most 2% by weight. The inevitable impurities are present at a proportion of at most 2% by weight, preferably at most 1% by weight or at most 0.5% by weight. However, the proportion of inevitable impurities is preferably lower and is at most 0.25% by weight or at most 0.1% by weight FIG. 2 shows a schematic longitudinal sectional representation of fluid conduit 1. Only the base body, which consists of layers 5, 6, 7 and 8, is indicated. Chafe layer 9 has been applied. It is clear that fluid conduit 1 has areas 10 and areas 11 in the axial direction with respect to longitudinal center axis 4, which alternate in the axial direction. In areas 10, chafe layer 9 consists of the thermoplastic polyurethane. In areas 11, on the other hand, it is made of a different material, for example a rubber-like material. This other material is preferably chosen in such a way that it can be detached from the base body more easily than the thermoplastic polyurethane.

[0102] FIG. 3 shows a further longitudinal sectional representation of fluid conduit 1 in schematic form. Again, there are areas 10 and areas 11. Provision is now made for an adhesion promoter 12 to be present in areas 10 between chafe layer 9 and the base body. This is not the case in areas 11. In these areas, the thermoplastic polyurethane is applied to the base body without using an adhesive. This facilitates stripping fluid conduit 1, i. e. removing chafe layer 9, in areas 11. In other words, chafe layer 9 adheres more strongly to the base body in areas 10 than in areas 11.

[0103] FIG. 4 shows a further configuration of fluid conduit 1 in a schematic longitudinal section. It can be seen that the base body has a surface structure 13 to which the chafe layer 9 is applied. In the exemplary embodiment shown here, surface structure 13 is composed of webs 14 spaced apart from one another in the axial direction, of which only a few are indicated here by way of example. The base body is formed in the manner of a corrugated tube by means of webs 14. The use of surface structure 13 improves mechanical adhesion of chafe layer 9 to the base body.