Antriebsriemen, insbesondere Zahnriemen, mit verbesserten Eigenschaften und Verfahren zur Herstellung hiervon

Abstract

In a first aspect, the present invention relates to a method for producing a drive belt, in particular a toothed belt, having a belt body composed of elastic material and a tension member with tensile strands composed of carbon cord. In this case, these carbon cords, in the form of twisted carbon cords, are soaked with a liquid isocyanate solution before they are used as tension members for the drive belts. In a further aspect, a drive belt which can be obtained in this way is provided. This drive belt is in particular a high performance belt, such as a high performance toothed belt, having improved belt running times and adhesion properties of the carbon cord to the belt body.

Claims

1. A method for producing a drive belt having a belt body composed of elastic material and tension members with tensile strands, wherein at least one tension member with the tensile strands of the tension members is formed from a multiplicity of carbon fibers which are twisted together to form a twisted carbon cord, comprising: treating the twisted carbon cord with a liquid isocyanate solution to produce a soaked, twisted carbon cord; optionally drying and optionally heat-treating the twisted carbon cord after soaking with liquid isocyanate solution; winding the soaked, twisted carbon cord in a form of tensile strands of the at least one tension member around a drum; introducing a solution of reaction partners to the soaked, twisted carbon cord wound on the drum for formation of the belt body composed of elastic material; forming the drive belt under the action of pressure and/or temperature on the reaction partners and the soaked, twisted carbon cord wound on the drum, wherein the belt body of the drive belt comprises the tension members with the at least one tension member that is composed of the twisted carbon cord, wherein the elastic material of the belt body at least partially encloses the tension members; wherein the soaked, twisted carbon cord is not subjected to curing before being brought into contact with the reaction partners for formation of the belt body.

2. The method according to claim 1, wherein the elastic material is a polyurethane material.

3. The method according to claim 1, wherein the isocyanate solution comprises a polyisocyanate.

4. The method according to claim 3, wherein the isocyanate solution is a methylene diphenyl isocyanate solution.

5. The method according to claim 1, wherein the isocyanate solution comprises a solvent.

6. The method according to claim 1 wherein the soaked, twisted carbon cord is dried and/or heat-treated, and wherein the isocyanate solution is present in an amount of 2-10% by weight in relation to the soaked, twisted carbon cord.

7. The method according to claim 1, wherein the liquid isocyanate solution has a viscosity in the range of the viscosity of toluene of 0.6 mPa×s.

8. The method according to claim 1, wherein no coating or soaking of the soaked, twisted carbon cord besides treating the twisted carbon cord with the liquid isocyanate solution is carried out before introduction of the solution of reaction partners for formation of the belt body composed of elastic material.

9. The method according to claim 1 wherein the twisted carbon cord has a tex of 200-3600 and/or a diameter of 0.3-2.4 mm.

10. The method according to claim 1 wherein the twisted carbon cord is a singly twisted carbon cord.

11. The method according to claim 1, further comprising applying a textile overlay as an outer layer to the belt body.

12. The method according to claim 1 wherein the reaction partners for formation of the belt body composed of elastic material are introduced as a prepolymer with a curing agent.

13. The method according to claim 1, wherein the introduction involves casting the reaction partners into a mold with the twisted carbon cord wound onto the drum.

14. A drive belt produced by the method according to claim 1.

15. The drive belt according to claim 14, wherein the belt body comprises belt teeth for formation of a toothed belt, and optionally comprises a coating with a textile overlay in a power transmission zone of the drive belt.

16. The method according to claim 3 wherein the polyisocyanate is a diisocyanate.

17. The method according to claim 5 wherein the solvent is an organic solvent.

18. The method according to claim 10 wherein the singly twisted carbon cord has a maximum of 60 turns per meter.

19. The method according to claim 11 wherein the applying is performed at a power transmission zone of the belt body.

20. The method according to claim 12 wherein the prepolymer is a polyurethane prepolymer with reactive isocyanate groups, and wherein the curing agent is a primary amine.

Description

[0051] The invention will be described below on the basis of exemplary embodiments which serve solely for illustration and do not restrict the scope of the invention, as described above.

[0052] FIGS. 1 to 3 show sectors of different cord cross sections with respect to the elastomeric material, here filled cord enclosed in polyurethane.

[0053] FIG. 1 shows a cross-sectional illustration, in which only one segment of a cord 10 is shown, with a cord 10 embedded in polyurethane with the strands 1 and carbon fibers 2 indicated therein. The polyurethane material 20 of the belt body embeds the cord, with the isocyanate 30 having been placed around the strands 1. In the boundary region 3, the isocyanate is in a state reacted with the polyurethane, such that good bonding of the cord to the belt body is effected here. It is also possible for the isocyanate solution to have potentially penetrated into the strands 1.

[0054] FIG. 2 shows a further exemplary embodiment. In this example, the isocyanate solution 30 is located in the form of a coating on one of the inner strands 1, such that the polyurethane 20 in the edge region of the cord can penetrate further into the interstices between the outer strands 1 of the cord material. In this case, an optimal mechanical interlocking of the polyurethane 20 of the belt body, said polyurethane embedding the cord 10, with the cord strands 1 is produced. The sufficient flexural stability and elasticity, and also bonding to the belt body, is ensured by the isocyanate 30. There is sufficient bonding between the isocyanate 30 and the polyurethane 20 at the common boundary surface 3.

[0055] FIG. 3 shows a third exemplary embodiment, in which the shown strands 1 of the cord 10 are coated with the isocyanate 30. In this way, the cord 10 is at the same time sheathed with the isocyanate 30. The correspondingly very large surface 3 with respect to the polyurethane 20 makes it possible to produce correspondingly good adhesion by bonding.

[0056] An essential aspect is that the cord is soaked if this cord is in the form of twisted carbon fibers, and that the isocyanate which is present on or in the cord after the soaking is not partially polymerized or otherwise reacted, or does so only to a very minor extent, prior to reaction with the reaction partners for formation of the elastic material of the belt body.