Tire with an element attached to the surface thereof and method for attaching an element to the surface of a tire

Abstract

A tire comprises an interior surface and an exterior surface, an accommodating region arranged on one of said interior and exterior surfaces, an adhesive layer arranged on the accommodating region and a member attached to the accommodating region by the adhesive layer, in which the adhesive layer is based on a silanized polyether.

Claims

1. A tire comprising: two beads; two sidewalls connected to the beads; a crown connected to the ends of the two sidewalls with a crown reinforcement; a radially exterior tread; a radially interior surface; an accommodating region arranged on the radially interior surface; a detachable protective film comprising a fluoropolymer, the detachable protective film radially covering the accommodating region to avoid any contact of the accommodating region during vulcanization of the tire; an adhesive layer arranged on said accommodating region upon removal of the detachable protective film after vulcanization of the tire; and a member consisting of only one assembly, the assembly comprising a rubber attachment layer attached to said accommodating region by said adhesive layer, wherein a force of peeling the detachable protective film from the accommodating region is less than 1 N/mm at 20° C., wherein said adhesive layer is based on a silanized polyether and is free of isocyanate, wherein the rubber attachment layer is based on at least one essentially unsaturated diene elastomer, at least one essentially saturated diene elastomer or a mixture thereof, wherein, the tire having a maximum axial width LT, an axial distance between a center of gravity of the member and a median plane EP of the tire is at least equal to 5% and at most equal to 25% of the maximum axial width LT of the tire, and wherein the member is attached to the radially interior surface opposite of the radially exterior tread, axially on an exterior side of a vehicle relative to the median plane EP of the tire.

2. The tire according to claim 1, wherein the silanized polyether is a polyoxypropylene.

3. The tire according to claim 1, wherein the member is a casing able to receive an electronic device.

4. The tire according to claim 1, wherein the member is an electronic device.

5. The tire according to claim 1, wherein the member is a rubber patch.

6. The tire according to claim 1, wherein a thickness of said adhesive layer is between 1 and 1.5 mm.

7. The tire according to claim 1, wherein the radially exterior tread comprises a set of circumferential grooves, and the center of gravity of the member is located in line with a circumferential groove of the tire tread.

8. The tire according to claim 1, wherein the radially exterior tread comprises a set of ribs, and the center of gravity of the member is located in line with a rib of the tire tread.

9. The tire according to claim 1, wherein the silanized polyether is an alkoxysilane-functional telechelic polyether.

10. The tire according to claim 9, wherein the alkoxysilane is methyldimethoxysilane.

Description

DESCRIPTION OF THE FIGURES

(1) Supplementary elements of the invention are now described with the help of the appended drawing, presented nonlimitingly, in which:

(2) FIG. 1 very schematically shows a radial section through a tyre in accordance with one embodiment of the invention;

(3) FIG. 2 presents, in partial radial section, a tyre blank in accordance with one embodiment of the invention;

(4) FIG. 3 illustrates a member with an attachment layer;

(5) FIG. 4 shows the member attached to the surface of the tyre; and

(6) FIG. 5 shows the member attached to the surface of the tyre at another preferential position.

(7) FIG. 1 schematically represents a radial section through a pneumatic tyre or tyre incorporating, at a given accommodating region 13, a protective film 12 according to one embodiment of the invention.

(8) This tyre 1 has a crown 2 reinforced by a crown reinforcement or belt 6, two sidewalls 3 and two beads 4, each of these beads 4 being reinforced with a bead wire 5. The crown reinforcement 6 is surmounted radially on the outside by a rubber tread 9. A carcass reinforcement 7 is wound around the two bead wires 5 in each bead 4, the turn-up 8 of this reinforcement 7 being, for example, arranged towards the exterior of the tyre 1. The carcass reinforcement 7 is, in a way known per se, composed of at least one ply reinforced by “radial” cords, for example of textile or metal, that is to say that these cords are arranged virtually parallel to one another and extend from one bead to the other so as to form an angle of between 80° and 90° with the median circumferential plane (plane perpendicular to the axis of rotation of the tyre which is situated equidistantly from the two beads 4 and passes through the middle of the crown reinforcement 6). An airtight layer 10 (or “inner liner”) extends from one bead to the other radially on the inside with respect to the carcass reinforcement 7. FIG. 1 also indicates the median plane EP of the tyre. The median plane is a plane perpendicular to the axis of rotation of the tyre which is located halfway between the two beads and passes through the middle of the crown reinforcement. This figure also indicates the maximum axial width of the tyre LT. This maximum axial width is measured at the sidewalls, the tyre being mounted on its rim and lightly inflated, i.e. inflated to a pressure equal to 10% of the nominal pressure as recommended, for example, by the Tire and Rim Association or TRA.

(9) The tyre 1 is such that its inner wall comprises a given accommodating region 13 covered radially on the inside by a protective film 12.

(10) The surface of the accommodating region 13 must be sufficient to obtain robust attachment of the member; those skilled in the art will know how to adjust the dimensions of the protective layer 12 as a function of the size and weight of the member to be attached.

(11) The detachable protective film 12 is a thermoplastic film comprising, by way of example, a fluoropolymer. The thermoplastic film is extendable, with low rigidity, and has plastic behaviour. This film must have a Tg (or M.p., if appropriate) greater than the vulcanization temperature of the pneumatic tyre. An example of a suitable film is the A5000 film from Aerovac Systèmes France. This film comprises a fluorinated ethylene/propylene or FEP copolymer. This film has a maximum usage temperature of the order of 204° C. and an elongation at break of greater than 300%. The thickness thereof is 25 μm. These features enable it, in an exemplary embodiment of the invention, to be put in place directly or on the building drum of the pneumatic tyre.

(12) As indicated in FIG. 2, the detachable protective film 12 makes it possible to save the accommodating region 13 from any contact with the building drum of the tyre then with the curing membrane of the vulcanization mould. The particular nature of this protective film enables it to be removed from the interior surface of the tyre after vulcanization. The removal of this protective film restores all the properties to the surface of the accommodating region of the tyre. The protective film 12 may be removed without tearing.

(13) The pneumatic tyre or tyre of FIG. 1 may be manufactured, as indicated in FIG. 2, by integrating the protective film into an unvulcanized blank of the tyre 1 using a building drum and the other techniques customary in the manufacture of pneumatic tyres. More specifically, the detachable protective film 12 arranged radially innermost is applied first to the building drum 15. All the other customary components of the pneumatic tyre are then successively applied.

(14) After shaping, the crown plies and the tread are applied to the tyre blank. The blank completed in this way is placed in a curing mould and vulcanized. During vulcanization, the protective film protects the curing membrane of the mould from any contact with the accommodating region 13.

(15) Upon removal from the curing mould, the protective film 12 is still attached to the accommodating region 13.

(16) The protective film 12 may be easily removed upon removal from the vulcanization mould of the tyre. It is also possible, and preferable, to leave this protective film in place until the member is attached.

(17) The protective film may also be applied to the chosen accommodating region 13 on the surface of the tyre after the shaping of the tyre blank and before the introduction thereof into the vulcanization mould.

(18) FIG. 3 schematically presents a member 20 comprising a casing 22 and an attachment layer 24. The material of the attachment layer 24 is a rubber compound. Those skilled in the art will know how to adapt the thickness of the attachment layer as a function of that of the adhesive layer and of the size and weight of the member.

(19) FIG. 1 thus presents a tyre 1 ready to receive a member.

(20) It is also possible to attach a member to an accommodating region 13 of a customary vulcanized tyre, that is to say without it comprising a protective film protecting the accommodating region.

(21) In this case, it is preferable to clean this accommodating region before attaching the member.

(22) This cleaning may be carried out, for example, by means of a high-pressure water jet. This cleaning makes it possible to remove the majority of the mould-release agents which were placed on this surface before the vulcanization of the tyre, to facilitate the detachment of the curing membrane of the tyre vulcanization mould.

(23) After cleaning, the surface of the accommodating region of the inner liner is dried.

(24) It is also possible to carry out this cleaning by brushing, or with a laser beam.

(25) FIG. 4 presents the assembly of the tyre of FIG. 1 and the member 20 attached to the inner surface thereof, on the inner liner. This tyre is characterized in that the adhesive layer 11 is based on a silanized polyether. The adhesive layer holds the member 20 in place.

(26) The member 20 is attached to the surface of the tyre easily and rapidly: After having removed the protective film 12 from the accommodating region 13 of the tyre 1, if necessary: an adhesive layer based on silanized polyether is applied to the surface of the accommodating region; application of the adhesive by spraying is also possible: in this case it may be carried out at a higher temperature to support the spraying technique (reduction in the viscosity of the adhesive); the attachment layer of the member is placed against the surface of the adhesive layer 11, preferably with a suitable contact pressure; the adhesive layer is then allowed to crosslink at room temperature, as has been described above.

(27) The crosslinking of the adhesive layer creates two high-quality bonds: between the adhesive and the inner liner on the one hand, and between the adhesive and the rubber attachment layer of the member on the other hand. The quality of these bonds is linked to an interpenetrating network originating from the polycondensation of the alkoxysilane-functional oligomers.

(28) Indeed, the macromolecular chains of the rubber compounds and of the silanized polyether adhesive are partially compatible, which enables intermolecular diffusion between the macromolecular chains to occur when the adhesive layer is brought into contact against the inner liner and the attachment layer of the member.

(29) Moreover, this diffusion is promoted on the one hand by the good mobility of the (not yet crosslinked) silanized polyether and on the other hand by the presence of small molecules such as the adhesion promoter, the dehydration agent and even the plasticizer (the three acting as a pseudo-solvent). Although it is only very superficial, this intermolecular diffusion is capable of ultimately generating an interpenetrating network after crosslinking of the silanized polyether. This entanglement of the molecules of each of the materials, with disappearance of the interface and creation of an interphase over a small thickness, must be responsible for the good adhesion which is observed and measured.

(30) In the example presented, the member is attached to the inner surface of the tyre; it is also possible to place it on an outer surface of the tyre, for example on the tyre sidewall.

(31) The surfaces of the accommodating region 13 and hence of the adhesive layer 11 must be sufficient to obtain robust attachment of the member; those skilled in the art will know how to adjust the dimension of the adhesive layer 11 as a function of the size and weight of the member to be attached.

Tests

(32) The benefit of the adhesive according to one of the subjects of the invention is shown by the results of a very high-speed resistance test.

(33) The tyres in question are of dimension 305/30ZR20 103Y, with an interior side I and an exterior side E, with a maximum axial width of 313 mm, and are tested with a camber angle of 2.5° in order to take into account the technical requirements of a vehicle for which they are specifically intended. The test consists in running on a metal rolling road 8.5 m in circumference, at a set pressure of 3.2 bar and a set load of 587 daN. The tyre runs at levels of increasing speed, lasting 20 minutes each, the speed increment being 10 km/h. The tyres are classified according to the maximum speed achieved and the length of running at the last speed level achieved.

(34) In this test, the member is a pressure and temperature sensor placed in a casing made of rubber compound based on cis-1,4-polybutadiene and on halogenated butyl, as described in document U.S. Pat. No. 8,763,658 B2.

(35) A comparison is made between a tyre not fitted with a member, a tyre with a member attached with a 0.3-0.4 mm thick adhesive layer of Gray-Gum supplied by Tech International and a tyre with a member attached with an approximately 1 mm thick adhesive layer of Bostik-Simson-ISR-7003.

(36) The tyre without the member reached the level of 370 km/h and ran at this speed for 11 minutes. The tyre according to the prior art, namely equipped with the electronic member, a pressure sensor weighing 7 g, positioned according to the prior art and therefore installed in the tyre in such a way that its centre of gravity is in the equatorial plane, to within the positioning tolerance of 1% of the maximum axial width, achieved the speed level of 340 km/h and failed after running under these conditions for one minute. This result, when compared with that of the tyre not fitted with the electronic member, demonstrates the drop in endurance performance at very high speed caused by the presence of the electronic member. This failure is linked to the approximately 15° C. increase in crown temperature seen by numerical simulation in line with the sensor, this being at the same speed on the tyre not fitted with an electronic member and on the tyre fitted with the electronic member according to the prior art.

(37) The inventors tested two embodiments of the invention. The first embodiment, illustrated in FIG. 5, consisted in installing the electronic member 20 at a distance from the equatorial plane of 16% of the maximum axial width LT, in line with a rib 30 of the tread 9. In this case, the tyre according to the invention achieved the speed level of 360 km/h and ran for 15 minutes at this level. This, when compared to the result of the tyre fitted with the electronic member positioned in the equatorial plane, namely the maximum achieved level of 340 km/h, demonstrates the improvement in high-speed endurance of the tyre fitted with the electronic member as described by the invention.

(38) The second embodiment, illustrated in FIG. 4, consisted in installing the electronic member 20 at a distance from the equatorial plane of 7% of the maximum axial width, in line with a groove 40 of the tread 9. In this case, the tyre according to the invention achieved the speed level of 370 km/h and ran for 15 minutes at this level. The maximum crown temperature dropped by almost 15° C. This result, when compared to the result of the tyre fitted with the electronic member positioned in the equatorial plane, namely the maximum achieved level of 340 km/h, shows the improvement in high-speed endurance of the tyre fitted with the electronic device as described by the invention according to this second embodiment.

(39) No difference in performance was observed between the two adhesive layers tested. However, a supplementary test using a cyanoacrylate-based adhesive showed that the latter is unsatisfactory.

(40) These results show that the use of an adhesive layer based on silanized polyether is a beneficial alternative to the use of a conventional bonding rubber such as Gray-Gum from Tech International.