TIRE READY TO RECEIVE A MEMBER ON THE SURFACE THEREOF

Abstract

A tire comprises an inner surface and/or outer surface with an accommodating region, an adhesive layer arranged on said accommodating region and a protective film arranged on said adhesive layer, characterized in that said adhesive layer is based on a block thermoplastic elastomer (TPE) comprising an elastomer block based on a diene elastomer comprising a molar content (or content by weight) of unsaturations of greater than 10%.

Claims

1.-25. (canceled)

26. A tire comprising an inner surface and/or outer surface with an accommodating region, an adhesive layer arranged on the accommodating region and a protective film arranged on the adhesive layer, wherein a composition of the adhesive layer is based on a block thermoplastic elastomer comprising a diene elastomer block with a molar content of diene units relative to all of the units of the elastomer block of greater than 10%.

27. The tire according to claim 26, wherein the molar content of diene units of the diene elastomer block of the composition of the adhesive layer relative to all of the units of the elastomer block is greater than 50%.

28. The tire according to claim 26, wherein the diene of the diene elastomer block is selected from the C4-C12 conjugated dienes.

29. The tire according to claim 26, wherein the diene elastomer block is a copolymer obtained by copolymerization of one or more dienes conjugated with one another or with one or more vinylaromatic compounds having from 8 to 20 carbon atoms.

30. The tire according to claim 26, wherein the diene of the diene elastomer block is selected from the group consisting of butadienes, isoprenes, and mixtures thereof.

31. The tire according to claim 26, wherein the diene elastomer block is based on isoprene.

32. The tire according to claim 26, wherein a thermoplastic block of the block thermoplastic elastomer of the composition of the adhesive layer is selected from the group consisting of polyamide, polyester and styrene blocks.

33. The tire according to claim 32, wherein the thermoplastic block of the block thermoplastic elastomer of the composition of the adhesive layer is a styrene block.

34. The tire according to claim 33, wherein the block thermoplastic elastomer is selected from the group consisting of styrene/isoprene block copolymers.

35. The tire according to claim 34, wherein the block thermoplastic elastomer is a predominantly styrene/isoprene diblock copolymer.

36. The tire according to claim 34, wherein the block thermoplastic elastomer is a predominantly styrene/isoprene/styrene triblock copolymer.

37. The tire according to claim 25, wherein the block thermoplastic elastomer of the composition of the adhesive layer is a block thermoplastic elastomer mixture.

38. The tire according to claim 25, wherein the block thermoplastic elastomer of the adhesive layer is the only elastomer of the adhesive layer.

39. The tire according to claim 25, wherein the protective film is a thermoplastic film selected such that the peel force of the protective film from the adhesive layer is less than 1 N/mm at 20° C.

40. The tire according to claim 39, wherein the protective film is selected from the group consisting of polyesters, polyamides and films comprising at least one fluoropolymer.

41. The tire according to claim 40, wherein the fluoropolymer comprises a fluorinated ethylene/propylene copolymer.

42. The tire according to claim 25, wherein the Tg or melting point, if appropriate, of the protective film is greater than the maximum curing temperature of the rubber mixture of the accommodating region.

43. A member intended to be fixed to the surface of a tire according to claim 25, wherein the member comprises an attachment layer, the composition of which is based on a block thermoplastic elastomer, the thermoplastic block of which is of the same nature as the thermoplastic block of the block thermoplastic elastomer of the composition of the adhesive layer of the accommodating region of the tire.

44. The member according to claim 43, wherein the composition of the attachment layer is based on a block thermoplastic elastomer identical to the block thermoplastic elastomer of the composition of the adhesive layer of the accommodating region of the tire.

45. The member according to claim 43, wherein the block thermoplastic elastomer of the attachment layer comprises an unsaturated diene elastomer block.

46. The member according to claim 43, wherein the block thermoplastic elastomer of the attachment layer comprises a saturated diene elastomer block.

47. The member according to claim 43, wherein the member is a casing able to receive an electronic device.

48. The member according to claim 43, wherein the member is an electronic device.

49. An assembly of a tire according to claim 25 and a member intended to be fixed to the surface of the tire, wherein the member comprises an attachment layer, the composition of which is based on a block thermoplastic elastomer, the thermoplastic block of which is of the same nature as the thermoplastic block of the block thermoplastic elastomer of the composition of the adhesive layer of the accommodating region of the tire.

50. A method for attaching a member according to claim 43 to the surface of the tire comprising the steps of: removing all or a portion of the protective film; bringing both the adhesive layer and the attachment layer to a temperature greater than the softening points of the thermoplastic blocks of the block thermoplastic elastomers; and bringing the attachment layer and the adhesive layer into contact by applying pressure thereto.

Description

DESCRIPTION OF THE FIGURES

[0117] Supplementary elements of the invention are now described with the help of the appended drawing, presented nonlimitingly, in which:

[0118] FIG. 1 represents, highly schematically (without being true to a specific scale), a radial section through a tyre in accordance with one embodiment of the invention;

[0119] FIG. 2 presents, in radial section, a tyre blank in accordance with one embodiment of the invention;

[0120] FIG. 3 illustrates a member with an attachment layer; and

[0121] FIG. 4 shows the member attached to the surface of the tyre.

[0122] FIG. 1 schematically represents a radial section through a pneumatic tyre or tyre incorporating, at a given accommodating region 13, an adhesive layer with a protective film according to one embodiment of the invention.

[0123] This tyre 1 comprises 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 outside 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 at mid-distance from the two beads 4 and passes through the middle of the crown reinforcement 6). An airtight layer 10 extends from one bead to the other radially internally relative to the carcass reinforcement 7.

[0124] The tyre 1 is such that its inner wall comprises, in a given accommodating region 13, an adhesive layer 11. The adhesive layer 11 is covered radially internally by a protective film 12. The thickness of the adhesive layer is preferably between 0.1 and 4 mm, and very preferentially between 0.2 and 2 mm. Those skilled in the art will know how to adapt this thickness as a function of the nature, the geometry and the weight of the member and also of the thickness of the attachment layer of the member.

[0125] The surface of the accommodating region 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 dimensions of the adhesive layer as a function of the size and weight of the member to be attached.

[0126] The adhesive layer 11 consists of a predominantly styrene/isoprene/styrene SIS triblock copolymer of D1161 grade, from Kraton.

[0127] 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 copolymer or FEP. 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 placed directly or on the building drum of the pneumatic tyre.

[0128] As shown in FIG. 2, the protective film 12 extends beyond the accommodating region of the adhesive layer. The extension must be greater than 2 mm to guarantee that this adhesive layer does not become contaminated during the vulcanization of the tyre.

[0129] The detachable protective film 12 makes it possible to separate the adhesive layer 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 inner surface of the tyre after vulcanization. The removal of its protective film restores all its properties to the surface of the adhesive layer. The protective film 12 may be removed without tearing.

[0130] The pneumatic tyre of FIG. 1 may be manufactured, as indicated in FIG. 2, by integrating the adhesive layer into an unvulcanized tyre blank 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. The adhesive layer 11 is then applied. All the other customary components of the pneumatic tyre are then successively applied.

[0131] 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 adhesive layer.

[0132] Upon removal from the curing mould, the protective film 12 is still attached to the adhesive layer 11.

[0133] 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.

[0134] The protective film and the adhesive layer may also be applied to the chosen accommodating region on the surface of the tyre after the shaping of the tyre blank and before the introduction thereof into the vulcanization mould.

[0135] FIG. 3 schematically presents a member 20 comprising a casing 22 and an attachment layer 24. The material of the attachment layer 24 is based on a block thermoplastic elastomer, the hard thermoplastic blocks of which are of the same nature as the hard blocks of the TPE(s) of the adhesive layer of the tyre. The attachment layer is preferentially based on the same TPE as that of the adhesive layer. The adhesive layer and attachment layer consist of a predominantly triblock TPE based on styrene and isoprene (SIS). The thickness of the attachment layer is preferably between 0.5 and 4 mm, and very preferentially between 2 and 3 mm. 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.

[0136] FIG. 4 presents the assembly of the tyre of FIG. 1 and the member 20 attached to the inner surface thereof, on the inner rubber.

[0137] The member 20 is fixed to the surface of the tyre easily and rapidly: [0138] all or a portion of the protective film 12 of the adhesive layer 11 of the tyre 1 is removed; [0139] the adhesive layer 11 of the tyre and the attachment layer 24 of the member are heated to temperatures greater than the Tg (or M.p., if appropriate) of these block thermoplastic elastomers; this heating may be carried out by any means (hot-air blowing, infrared radiation, etc.); the surface regions of the two adhesive and attachment layers are then above their processing temperatures and are thus softened; [0140] the attachment layer and the adhesive layer are brought into contact by applying a contact pressure; this contacting enables the two layers to interpenetrate one another due to the high molecular mobility linked to the temperature; and [0141] contact is maintained until the two adhesive and attachment layers are cooled to below the Tg (or M.p., if appropriate) values of the TPEs.

[0142] The contact pressure is preferably greater than 0.05 bar. Those skilled in the art will know to adjust this as a function of the attachment and adhesive layers used.

[0143] As soon as the cooling is achieved, the member is robustly attached to the surface of the tyre.

[0144] In the examples 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.

Tests

Manual Peel Test

[0145] Adhesion tests (peel tests) were performed to test the capacity of the adhesive layer to adhere after curing to a diene elastomer layer, more precisely to a customary rubber composition for an inner tyre rubber (tyre liner) based on butyl rubber (copolymer of isobutylene and isoprene), also comprising the customary additives (filler, sulphur, accelerator, ZnO, stearic acid, antioxidant). Of course, this test may be adapted to the case in which the member must be placed on the tyre sidewall; in this case, to produce the test specimens, a layer of rubber sidewall mixture will be used instead of a layer of customary inner rubber.

[0146] The peeling test specimens (for 180°-type peeling) were prepared by stacking on the one hand a fabric of passenger vehicle carcass ply type and an adhesive SIS layer (1.5 mm), and on the other hand an identical fabric and a layer of customary inner rubber (1.2 mm) or an adhesive SIS layer. Each part is produced separately at 180° C. for 15 minutes in a press comprising platens.

[0147] These two parts are then assembled by bringing the SIS surface and the inner rubber surface into contact under a pressure of 0.1 bar for 1 min at 180° C. An incipient crack is inserted between the two calendered fabrics at the end of the adhesive layer.

[0148] Strips with a width of 30 mm were cut out using a cutting machine. The two sides of the incipient crack were subsequently placed in the jaws of a tensile testing device with the Instron® brand name. The tests are performed at room temperature and at a pull speed of 100 mm/min. The tensile stresses are recorded and the latter are standardized by the width of the test specimen. A curve of strength per unit of width (in N/mm) as a function of the movable crosshead displacement of the tensile testing machine (between 0 and 200 mm) is obtained. The adhesion value selected corresponds to the initiation of failure in the test specimen and thus to the maximum value of this curve.

[0149] Examples: C-1 is a customary inner rubber composition; C-2 is an adhesive layer in accordance with the invention; C-3 is an attachment layer in accordance with the invention.

TABLE-US-00002 TABLE 1 Composition C-1 C-2 C-3 Butyl elastomer (1) 100 Carbon black (N772) 50 Zinc oxide 1.5 Stearic acid 1.5 Sulphenamide (2) 1.2 Sulphur 1.5 Kraton D1161 SIS 100 100 (1) Brominated polyisobutylene, Bromobutyl 2222, sold by Exxon Chemical Co; (2) N-Dicyclohexyl-2-benzothiazolesulphenamide (Santocure CBS from Flexsys).

Test Results

[0150] The value obtained for adhesion of C-2 on C-3 is multiplied by 13 relative to the value for adhesion of C-2 on C-1.

TABLE-US-00003 TABLE 2 Evaluation of the adhesion between the surfaces C-2 on C-1 C-2 on C-3 Adhesion values (N/mm) 0.3 4

[0151] The invention thus enables rapid and reversible attachment of members to the surface of a tyre without the drawbacks linked to the preparation of the contact surface.

[0152] This attachment is reversible, that is to say that the two adhesive and attachment layers may be disassembled by heating above the Tg (or M.p., if appropriate) values of their hard blocks, then passage of a tool. The adhesive layer uncovered in this way may then be used again to adhesively bond the same member or another.

[0153] The adhesive bonding solutions developed are environmentally friendly and do not use irreversible chemical crosslinking.

[0154] Finally, this method of attachment affords a high degree of freedom as regards the geometry and functions of the member, due to the attachment post-vulcanization.