PNEUMATIC VEHICLE TIRE WITH NOISE ABSORBER, AND METHOD FOR DETECTING A PNEUMATIC VEHICLE TIRE WITH NOISE ABSORBER AND FOR RECYCLING A PNEUMATIC VEHICLE TIRE WITH NOISE ABSORBER

Abstract

The invention relates to a pneumatic vehicle tire with at least one sound absorber adhesively attached in its interior to the inner surface opposite the tread. The invention further relates to a process for detecting a pneumatic vehicle tire with a sound absorber and to a process for recycling a pneumatic vehicle tire with a sound absorber.

According to the invention the radially inward-facing surface of the sound absorber has at least one luminescent agent applied to it.

The tire according to the invention is detected via the luminescent agent.

Claims

1.-12. (canceled)

13. A pneumatic vehicle tire comprising: a tread, sidewalls and an inner layer opposite the tread; a sound absorber attached to the inner layer, in the form of a foam ring having an elongated triangle cross section, matched to a tire cavity frequency and having a radially inward facing surface; and a luminescent agent applied to radially inward facing surface of the sound absorber.

14. The tire of claim 13, the luminescent agent is a fluorescent agent or phosphorescent agent.

15. The tire of claim 13, the luminescent agent absorbs light in the wavelength range from 200 to 700 nm and emits light in the wavelength range from 350 to 800 nm.

16. The tire of claim 15, the luminescent agent being dispersion applied by a solution that contains from 1% to 80% by weight of luminescent agents.

17. The tire of claim 13, the luminescent agent covers 0.01% to 100% of the radially inward facing surface of the sound absorber.

18. The tire of claim 13, the luminescent agent comprises a film attached to the radially inward facing surface.

19. The tire of claim 18, the sound absorber comprising a porous damping element.

20. The tire of claim 19, the foam ring being closed.

21. The tire of claim 13, the sound absorber comprises polyurethane.

22. The tire of claim 13, the luminescent agent applied with a random distribution in spatial regions of the radially inward facing surface.

23. The tire of claim 13, the luminescent agent applied as a plurality of parallel strips.

24. The tire of claim 13, the luminescent agent being a film having a film thickness in a radial direction (rR) perpendicular to an axial direction (aR) of the tire of 100 nm (nanometers) to 3500 μm (micrometers).

25. The tire of claim 13, the luminescent agent is hydrophilic or hydrophobic.

26. A method of recycling a tire, the method comprising: providing a tire to be recycled, the tire comprising a sound absorber attached to an inner layer, in the form of a foam ring having an elongated triangle cross section, matched to a tire cavity frequency and having a radially inward facing surface; determining presence of a luminescent agent on the radially inward facing surface of the sound absorber; removing the sound absorber based on the determined presence of the luminescent agent; and recycling the tire based after removing the sound absorber.

27. The method of claim 26, determining the presence of the luminescent agent comprises using a photo-diode.

Description

[0070] In a preferred embodiment the at least one sound absorber is at least one porous damping element. Porous materials especially have the advantage that in addition to sound absorption they also introduce into the tire an intrinsic weight that is not excessive and the rolling resistance properties of the tire are therefore not unnecessarily impaired.

[0071] The porous material from which the damping element is formed is for example selected from the group containing polyurethane, in particular polyether-based and/or polyester-based polyurethane foams having a density of 18 to 300 kg/m.sup.3, preferably 30 to 35 kg/m.sup.3, and a hardness of 6.5 kilopascals, polyesters having a density of 18 to 300 kg/m.sup.3 preferably 30 to 35 kg/m.sup.3, and a hardness of 6.5 kilopascals, polyethers, and also any porous, sound-absorbing material mixtures, for example glass or rock wool, loop-pile or deep-pile fabric or nonwovens or cork. Further possible porous materials which are suitable for utilization as a damping element are for example a melamine resin foam or a builder's foam.

[0072] It is particularly preferable when the sound absorber, preferably at least one porous damping element, contains at least one polyurethane. Polyurethane is particularly suitable on account of its specific density and further nature and also its availability.

[0073] In a particularly advantageous embodiment the porous damping element is a sound-absorbing foam ring closed or open in the circumferential direction. Said ring ensures even sound absorption and the tire maintains its uniformity. The ring may be closed in the circumferential direction or be open in the form of a strip, wherein the ends of the strip may or may not be in contact or may also overlap.

[0074] The foam of the foam ring is preferably an open-celled foam since said foam is best suited for absorbing sound.

[0075] It is particularly preferable when the sound absorber is a closed sound-absorbing foam ring made of polyurethane, particularly preferably a polyether-based polyurethane foam.

[0076] Such foams are known to those skilled in the art.

[0077] The sound absorber(s) may moreover have any desired shape, for example individual elements in the shape of blocks, strips or the like, which may be combined with one another as desired.

[0078] The sound absorber or sound absorbers are preferably adhesively attached to the tire inner surface using an adhesive. Exemplary adhesives and combinations of adhesives include: an adhesive tape and/or a silicone-based adhesive and/or a two-component adhesive and/or a construction adhesive and/or a polyurethane adhesive and/or a rubber-based adhesive and/or a tire repair adhesive and/or an instant adhesive and/or an adhesive based on cyanoacrylate and/or based on a water-based acrylic system having a polyethylene terephthalate structure and/or based on acrylonitrile-butadiene rubber in conjunction with a formaldehyde resin dissolved in acetone and/or based on a silane polyether and/or based on a polybutene crosslinked with butyl rubber and/or based on an alkoxysilicone.

[0079] Such adhesives especially have the advantage that they can be applied in an amount sufficiently small to ensure that they have cured after bonding. This ensures that they are not tacky after removal of the sound absorber and before comminution during recycling of the tires, thus allowing the tires without the sound absorber to be comminuted in the known manner.

[0080] The sound absorber is applied to the inner surface of the tire using processes and apparatuses known to those skilled in the art.

[0081] The luminescent agent is applied to the radially inward-facing surface of the sound absorber according to its type. It may in particular be applied as a suspension, emulsion or solution.

[0082] The invention further provides a process for detecting a pneumatic vehicle tire according to the invention to distinguish pneumatic vehicle tires comprising a sound absorber from pneumatic vehicle tires without a sound absorber.

[0083] In the process according to the invention the sound absorber is detected by an operator or using a detector as a result of the luminescent agent.

[0084] The detector may in particular be a photodiode.

[0085] Suitable detectors are known to those skilled in the art and are usually computer-aided.

[0086] The detector may further be a handheld device or a detector used in an automated process by a robot.

[0087] The invention further provides a process for recycling pneumatic vehicle tires according to the invention comprising at least the process steps of:

A) providing the pneumatic vehicle tire to be recycled;
B) performing the process according to the invention for detecting a pneumatic vehicle tire according to the invention as a result of the luminescence;
C) separating the sound absorber from the pneumatic vehicle tire;
D) subsequently comminuting the pneumatic vehicle tire without the sound absorber.

[0088] In advantageous embodiments the process steps A) to D) are carried out in an automated manner.

[0089] The invention further provides a process for recycling pneumatic vehicle tires comprising at least the process steps of:

a) providing pneumatic vehicle tires to be recycled;
b) performing the process according to the invention for detecting a pneumatic vehicle tire according to the invention in order to distinguish pneumatic vehicle tires with a sound absorber from pneumatic vehicle tires without a sound absorber;
c) spatially separating pneumatic vehicle tires comprising a sound absorber from pneumatic vehicle tires without a sound absorber;
d) recycling pneumatic vehicle tires without sound absorbers comprising comminution of the pneumatic vehicle tires;
e) transferring pneumatic vehicle tires comprising a sound absorber to a separate recycling process comprising separation of the sound absorber and comminution of the pneumatic vehicle tires only subsequently.

[0090] In advantageous embodiments the process steps a) to e) are carried out in an automated manner. In an advantageous embodiment of the invention step c) is carried out in an automated manner in conjunction with step b).

[0091] Further particulars of the invention are more particularly elucidated with reference to FIG. 1, which is a schematic representation of an exemplary embodiment.

[0092] The invention shall be more particularly elucidated hereinbelow with reference to exemplary embodiments. An example of a pneumatic vehicle tire according to the invention is shown in FIG. 1 in the context of a schematic representation.

[0093] FIG. 1 depicts a cross section through a radial passenger motor vehicle tire having a profiled tread 1, sidewalls 2, bead regions 3, bead cores 4 and also a multi-ply belt bandage 5 and a carcass insert 6. On its inner surface, the tire is covered with an inner layer 7 of an airtight rubber compound. On the inner surface of the inner layer 7 opposite the tread strip 1 a sound-absorbing foam ring as sound absorber 9 is subsequently (in the finished tire) adhesively attached using an adhesive 8, for example a polyurethane-based adhesive 8.

[0094] With respect to its sound-absorbing properties the sound-absorbing foam ring is matched to the tire cavity frequency. The sound absorber 9 in the form of a foam ring here has for example approximately an elongated triangle cross section that is symmetrical with respect to the tire equator.

[0095] The foam of the foam ring is an open-celled foam since said foam is particularly well suited for absorbing sound. The foam comprises polyurethane for example.

[0096] The sound absorber 9 has a radially inward-facing surface 9a.

[0097] According to the example in FIG. 1 the radially inward-facing surface 9a of the sound absorber 9 has at least one luminescent agent 10 applied to it.

[0098] The luminescent agent 10 is applied, for example, in a solution or suspension. The liquid of the solution or suspension is, for example, water, wherein styrene-acrylate copolymer is further present as a binder.

[0099] The luminescent agent 10 may be any of the abovementioned agents which is soluble or suspensible in water, such as Rhodamine 6G for example.

[0100] The sound absorber 9 is thus luminescent on the inward-facing surface 9a. The liquid of the suspension is, for example, water, wherein styrene-acrylate copolymer may further be present as a binder.

[0101] The luminescent agent 10 covers, for example, 5% of the surface 9a of the sound absorber 9.

[0102] In FIG. 1 the luminescent agent 10 has been applied with a random distribution in individual spatial regions 11, as illustrated again in plan view in FIG. 1a. FIG. 1a shows a schematic sector of the plan view of the radially inward-facing surface 9a.

[0103] FIG. 2 likewise shows a schematic sector of the plan view of the radially inward-facing surface 9a. In FIG. 2, the luminescence agent 10 has been applied in the form of a plurality of parallel strips 12. There may be three (see FIG. 2) or four strips (not shown in the figures) for example.

[0104] In FIG. 3 the luminescent agent 10 covers almost the entire surface 9a.

[0105] After excitation, in particular by light in the wavelength range from 200 to 700 nm, the luminescence through emission of light in the wavelength range from 350 to 800 nm may either be identified by an operator or detected using a photodiode.

[0106] The pneumatic vehicle tire described by way of example can now be distinguished, using a photodiode, from pneumatic vehicle tires without a sound absorber by the process according to the invention as a result of the luminescence.

[0107] This allows pneumatic vehicle tires with sound absorbers according to the invention and pneumatic vehicle tires without sound absorbers to be distinguished from one another in a, for example automated, process according to the invention, spatially separated and supplied to different recycling processes. In the case of a tire according to the invention sound absorbers comprising luminescent agent are initially removed from the tire in an additional step.

LIST OF REFERENCE NUMERALS

(Part of the Description)

[0108] 1 Tread [0109] 2 Sidewall [0110] 3 Bead region [0111] 4 Bead core [0112] 5 Belt bandage [0113] 6 Carcass insert [0114] 7 Inner layer [0115] 8 Adhesive [0116] 9 Sound absorber [0117] 9a Radially inward-facing surface of the sound absorber [0118] 10 Luminescent agent [0119] 11 Individual spatial regions [0120] 12 Strips [0121] rR radial direction [0122] aR axial direction [0123] UR circumferential direction of the tire