Pneumatic vehicle tyre with air-discharging threads and method for manufacturing an electrically conductive coating for the air-discharging threads

Abstract

The invention relates to a pneumatic vehicle tire (1) of radial design having a carcass (4) and having components (9, 10) which adjoin the carcass (4), wherein thread-shaped elements (11) are arranged on at least one of the two surfaces of the carcass (4) and preferably serve to discharge occluded air between the carcass (4) and the adjoining components (9, 10) during the construction of the tire. In order to improve the electrical conductivity of the pneumatic vehicle tire (1), at least one thread-shaped element (11) has a coating which is electrically conductive and jointly forms an electrically conductive, thread-shaped element (12) which has an electrical resistance of <1×10.sup.7 Ohm/cm. The invention also relates to a method for manufacturing the electrically conductive coating.

Claims

1. A pneumatic vehicle tire in radial construction comprising: a carcass having an inner surface and an outer surface; at least one component adjoining the carcass, the at least one component being at least one of an inner layer adjoining the inner surface of the carcass and a side wall adjoining the outer surface of the carcass; a plurality of thread-shaped elements spaced from each other in a circumferential direction of the carcass and being arranged between at least one of: the inner surface of the carcass and the inner layer and the outer surface of the carcass and the side wall, wherein the plurality of thread-shaped elements comprise one of cotton or polyethylene and extend over an entire axial width of the carcass; at least one of the plurality of thread-shaped elements having a coating that is electrically conductive to form an electrically conductive, coated thread-shaped element having an electrical resistance of <1×10.sup.7 ohm/cm; and at least one of the plurality of thread-shaped elements having no electrically conductive coating, wherein the plurality of thread-shaped elements define a plurality of air discharge paths between the at least one of the inner surface of the carcass and the inner layer and the outer surface of the carcass and the side wall, which are arranged to discharge, during construction, air enclosed between the at least one of the carcass and the inner layer and the carcass and the side wall.

2. The pneumatic vehicle tire as claimed in claim 1, wherein the at least one of the thread-shaped elements having a coating to form an electrically conductive, thread-shaped element comprises between 1 and 20 electrically conductive, thread-shaped elements being arranged on the at least one surface of the carcass.

3. The pneumatic vehicle tire as claimed in claim 1, wherein the at least one of the thread-shaped elements having a coating that is electrically conductive to form an electrically conductive, thread-shaped element comprises between 2 and 6 electrically conductive, thread-shaped elements being arranged on the at least one of the inner and outer surfaces of the carcass.

4. The pneumatic vehicle tire as claimed in claim 1, wherein, in an unvulcanized tire, the electrically conductive, thread-shaped element has an extensibility of 1.5% to 50%.

5. The pneumatic vehicle tire as claimed in claim 1, wherein in an unvulcanized tire, the electrically conductive, thread-shaped element has an extensibility of 5% to 25%.

6. The pneumatic vehicle tire as claimed in claim 1, wherein the thread-shaped elements are not electrically conductive.

7. The pneumatic vehicle tire as claimed in claim 1, wherein diameters of the thread-shaped elements are between 0.01 and 1.5 mm.

8. The pneumatic vehicle tire as claimed in claim 1, wherein diameters of the thread-shaped elements are between 0.05 and 0.2 mm.

9. The pneumatic vehicle tire as claimed in claim 1, wherein the electrically conductive, thread-shaped element has a titer<3000 dtex.

10. The pneumatic vehicle tire as claimed in claim 1, wherein the electrically conductive, thread-shaped element has a titer<500 dtex.

11. The pneumatic vehicle tire as claimed in claim 1, wherein the electrically conductive coating is an adhesion promoter that contains electrically conductive particles.

12. The pneumatic vehicle tire as claimed in claim 11, wherein the adhesion promoter comprises a resorcin formaldehyde latex (RFL) dip and the electrically conductive particles comprise carbon black having a specific surface area≥50 m.sup.2/g.

13. The pneumatic vehicle tire as claimed in claim 12, wherein the carbon black has a specific surface area≥100 m.sup.2/g.

14. The pneumatic vehicle tire as claimed in claim 11, wherein the electrically conductive coating comprises a carbon black dip.

15. The pneumatic vehicle tire as claimed in claim 1, wherein the electrically conductive coating is between 10 and 90 wt % of the at least one electrically conductive, thread-shaped element.

16. The pneumatic vehicle tire as claimed in claim 15, wherein the electrically conductive coating is between 10 and 50 wt % of the at least one electrically conductive, thread-shaped element.

17. The pneumatic vehicle tire as claimed in claim 15, wherein the electrically conductive coating is between 15 and 35 wt % of the at least one electrically conductive, thread-shaped element.

18. The pneumatic vehicle tire as claimed in claim 1, further comprising: a head region; and bead regions, wherein rubber mixtures of the head region and the bead regions are electrically conductive rubber mixtures, and a rubber mixture of at least one of the carcass, the side wall region and the inner layer is inadequately electrically conductive.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be explained in greater detail on the basis of two figures, which show schematic exemplary embodiments. In the figures:

(2) FIG. 1 shows a partial section through a pneumatic vehicle tire; and

(3) FIG. 2 shows a cross section through an electrically conductive, thread-shaped element.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(4) FIG. 1 shows a radial partial section through a passenger automobile pneumatic vehicle tire. The pneumatic vehicle tire 1, which includes rubber mixtures, has a radial carcass 4, extending from bead region 2 to bead region 3. Carcass 4 includes an inlay made of strength carriers embedded in rubber being guided around bead cores 5, which have high tensile strength, from the axial inside to the axial outside, ending in a carcass fold-up 8. The pneumatic vehicle tire 1 also has a tread 6 and components, such as the inner layer 9 and the side wall 10, adjoining the carcass 4. The belt 7 is arranged between the carcass 4 and the tread 6. The inner layer 9 adjoins the inner surface of the carcass 4, while the side wall 10 adjoins the outer surface of the carcass 4. Thread-shaped elements in the form of air-discharging threads 11 made of cotton or PET of the structure of 50 to 500 dtex are arranged on at least one of the two surfaces of the carcass 4, cf. FIG. 2. The air-discharging threads 11 are used for the purpose of discharging the air enclosed during the tire construction between the carcass 4 and the adjoining components inner layer and/or side wall 9, 10.

(5) The air-discharging threads 11 are arranged at an interval of 25 to 40 mm—measured in the peripheral direction—on the surface of the carcass 4 in radial orientation and have a diameter of <0.3 mm, preferably 0.05 to 0.2 mm. The air-discharging threads 11 preferably span the full carcass layer width.

(6) Between 2 and 6 of the air-discharging threads 11 of the tire are designed to be electrically conductive as electrically conductive, thread-shaped elements 12, while the remaining air-discharging threads 11 are designed as known. These electrically conductive elements 12 are arranged distributed regularly around the circumference of the tire on the carcass 4. The electrically conductive, thread-shaped element 12 is an air-discharging thread 11 having an electrically conductive coating 13. The air-discharging thread is a yarn, comprising filaments 15, and has the structure 235 dtex×1. The coating, in relation to the blank thread-shaped element 11, makes up between 20 and 40 wt % of the thread-shaped element. The electrically conductive coating is resorcin formaldehyde latex (RFL) dip having carbon black with a specific surface area≥50 m.sup.2/g, which has a carbon black proportion of 15 to 50 wt %, and preferably a carbon black proportion of 20 to 40 wt %, in the dry state. This abovementioned carbon-black-containing RFL dip ensures the desired electrical conductivity and simultaneously allows good bonding to rubber and good adhesion of the carbon black on the thread-shaped element. The coated air-discharging thread 12 and the air-discharging threads 11 are arranged over the entire axial width of the carcass 4.

LIST OF REFERENCE NUMERALS

(7) 1 pneumatic vehicle tire 2 bead region 3 bead region 4 carcass 5 bead core 6 tread 7 belt 8 carcass fold-up 9 inner layer 10 side wall 11 air-discharging thread (thread-shaped element) 12 coated air-discharging thread (electrically conductive, thread-shaped element) 13 electrically conductive coating 14 electrically conductive particle 15 filament aR axial direction rR radial direction