Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
  • C09J175/04—Polyurethanes
  • C09J175/14—Polyurethanes having carbon-to-carbon unsaturated bonds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/58—Epoxy resins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/67—Unsaturated compounds having active hydrogen
  • C08G18/6705—Unsaturated polymers not provided for in the groups C08G18/671, C08G18/6795, C08G18/68 or C08G18/69
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/67—Unsaturated compounds having active hydrogen
  • C08G18/68—Unsaturated polyesters

Definitions

• the present invention relates to adhesive systems that can be used for bonding, in composite materials, polyurethane to rubber, more specifically to bonding polyurethane fired to diene elastomers in the green (uncured) state.
• the present invention also relates to tires mounted on wheels and designed to be able to carry a substantial load without inflation pressure, also called non-pneumatic tires.
• Patent Application WO-A-00/37269 (or US Pat. No. 6,640,589) has proposed a non-pneumatic elastic bandage characterized by a bearing structure essentially comprising a plurality of support elements arranged substantially radially, in a cyclic symmetry. around the circumference of the bandage.
• a bearing structure essentially comprising a plurality of support elements arranged substantially radially, in a cyclic symmetry. around the circumference of the bandage.
• This bandage carries a load, a number of support elements present in the contact area are subjected to a large bending, which allows them to develop a force of recovery of part of the load.
• An interconnection structure makes the support elements work together, transferring the stresses to the adjacent support elements.
• this bandage to carry a certain load comes from the bending stress of the support elements present in the contact area of the non-pneumatic elastic bandage, and it also comes from the stress also in bending, the support elements outside. the contact area of the non-pneumatic elastic bandage, via this interconnection structure.
• the support elements or arches 2 comprising for example a stack of material blades.
• Composite, flexible, embedded in a rubber matrix, carry the load. They do not work completely isolated from each other, but they are interconnected by an interconnection structure 3 surmounted by a tread 13, both of diene elastomer, with interposition of elastic joints 4 so to ensure a good overall operation, avoiding shear too intense, and so as to provide good uniformity, that is to say a relative constancy of properties regardless of the circumferential position of the bandage relative to the ground.
• each elastic joint 4 is itself preferably formed of a diene elastomer composition such as those used for the sidewalls of the tires (sufficiently low hysteresis and satisfactory resistance to tearing) , which allows the elastic joints to function properly in their role of transmitting the forces between the support elements 2 and the interconnection structure, while accepting large and repeated deformations.
• a diene elastomer composition such as those used for the sidewalls of the tires (sufficiently low hysteresis and satisfactory resistance to tearing) , which allows the elastic joints to function properly in their role of transmitting the forces between the support elements 2 and the interconnection structure, while accepting large and repeated deformations.
• the excellent compatibility existing between the essentially unsaturated diene elastomers ensures in a known manner a very robust adhesion between the different parts.
• EP-A-I 359 028 specifies that another material capable of giving excellent results for this elastic articulation 4 is polyurethane.
• polyurethane has many advantages, including excellent tensile strength, tear resistance, abrasion and chemical resistance, and especially low hysteresis.
• a major disadvantage of polyurethane lies in the difficulty of properly bonding this product to a diene elastomer part, as also requires the structure of the non-pneumatic tire described above.
• liquid polyurethane glues capable of bonding the baked (that is to say polymerized) polyurethane to diene rubbers in the cured (vulcanized) state
• this requires polymerization of the polyurethane on the one hand and to cook the rubber separately, independently, before treating them together for gluing (see for example US 4,942,093).
• the level of adhesion obtained hot typically at a temperature of the order of 90 ° C to 100 0 C, is known to be insufficient vis-à-vis the requirements of a bandage, whether it is moreover, non-pneumatic as a tire, for a road vehicle capable of driving at a high speed in a sustained manner.
• the Applicant has. unexpectedly found a new adhesive system that allows to stick directly and effectively a polyurethane baked raw rubber, thus avoiding, in particular, the intermediate steps of preparation on a rigid core and then cooking separately from the top of the bandage no pneumatic described above.
• the radial structure constituted by the hoops 2 can act as a rigid core on which it is directly deposited said upper portion of the tire (tread 13 and interconnection structure 3) to the state of gum flood.
• This solution offers, after cooking, excellent adhesion between the polyurethane and the diene rubber, not only at room temperature but also, which is all unexpected and remarkable for the skilled person, at a high temperature of use.
• the invention relates to an adhesive composition, which can be used in particular as an adhesion primer for bonding a polymerized polyurethane to a diene elastomer composition in the green state, characterized in that comprises at least one polyisocyanate compound and a polyester or vinyl ester resin having functional groups reactive with isocyanate groups of said polyisocyanate compound, the total number of these isocyanate groups being in excess relative to the total number of said functional groups of the resin polyester or vinylester.
• the invention also relates to a pre-adhesive polyurethane coated with an adhesive or primary adhesion composition according to the invention.
• the invention also relates to an adhesive system that can be used for bonding a baked polyurethane to a diene elastomer composition in the green state, comprising in combination such a composition as an adhesion primer and a secondary adhesive for diene elastomer, capable of bonding to the vinylester or polyester resin of the adhesion primer.
• the invention also relates to the use, for the bonding of a baked polyurethane to a diene elastomer composition in the green state, of such an adhesive composition (or adhesion primer) or of such an adhesive system both in accordance with the invention.
• the invention also relates to a method for adhering a baked polyurethane to a diene elastomer composition in the green state, comprising at least the following steps:
• the invention also relates per se, before and after firing, to a composite comprising at least a first polyurethane part integral with a second diene rubber part by means of an adhesive interphase, characterized in that said adhesive interphase is based on at least one polyisocyanate compound, a polyester or vinylester resin having isocyanate-reactive functional groups of said polyurethane, and a secondary adhesive for diene elastomer capable of bonding to the vinylester or polyester resin of the primary accession.
• the invention also relates to the use of said composite for the manufacture of a rubber article, as well as any rubber article comprising such a composite.
• the invention relates in particular to the use of such a composite for the manufacture or reinforcement of any ground connection system of motor vehicles, such as non-pneumatic tire, tire, internal safety support for tire, wheel, spring rubber, elastomeric hinge, other suspension and anti-vibratory element, or semi-finished products made of rubber and polyurethane intended for such ground connection systems.
• the invention also relates to the ground connection systems and the semi-finished products of rubber and polyurethane themselves, when they comprise a composite according to the invention.
• the invention relates particularly to a pneumatic or non-pneumatic tire, such a tire being able to equip any type of motor vehicle, for example of the tourism type, two wheels (including motorcycles), aircraft, such as industrial vehicles chosen from vans. , "Heavy goods vehicles” - that is, metros, buses, road transport vehicles (trucks, tractors, trailers), off-the-road vehicles such as agricultural or civil engineering vehicles -, other road vehicles transportation or handling.
• the present invention provides a novel adhesive system employing a specific primary adhesive and secondary adhesive, both of which are described in detail herein. -after.
• the adhesive composition according to the invention is essentially based on a. polyisocyanate compound and a vinylester or unsaturated polyester resin, said resin having functional groups reactive with isocyanate groups of the polyisocyanate compound.
• An essential feature of this adhesive composition, so that it can react with the surface of the polyurethane, is that the total number of isocyanate groups in the compound polyisocyanate is in excess (stoichiometric) with respect to the total number of said functional groups of said resin.
• polyisocyanate compound any type of polyisocyanate compound, the latter being however preferably chosen from the group consisting of diisocyanates, triisocyanates and mixtures of such compounds.
• diisocyanates are used, for example para-phenylene diisocyanate (PPDI), tolidene diisocyanate (TODI), isophorone diisocyanate (IPDI), 4,4'-methylene bis (phenylisocyanate) (MDI), toluene diisocyanate (TDI), naphthalene-1,5-diisocyanate (NDI) and equivalent products.
• PPDI para-phenylene diisocyanate
• TODI tolidene diisocyanate
• IPDI isophorone diisocyanate
• MDI 4,4'-methylene bis (phenylisocyanate)
• TDI toluene diisocyanate
• NDI naphthalene-1,5-diisocyanate
• This polyisocyanate compound is more preferably selected from the group consisting of diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI) and mixtures of these compounds.
• MDI diphenylmethane diisocyanate
• TDI toluene diisocyanate
• MDI diphenylmethane diisocyanate
• TDI liquid at room temperature, well adapted reactivity, is particularly preferred.
• the resin of the polyester type (polyester resin, is understood in a known manner unsaturated polyester resin) or vinylester has the essential feature of having isocyanate-reactive functional groups of the polyisocyanate compound.
• reactive functional groups those selected from the group consisting of hydroxyl (-OH), carboxyl (-COOH), thiol (-SH), amino groups (primary or secondary) - NH, -NH 2 and -NHR, the amide groups -CONH 2 and -CONHR, thioamides -CSNH 2 and -CSNHR 5 sulfonic -SO 2 OH, and the mixtures of such functional groups, the substitutive radical R representing here a radical any monovalent hydrocarbon (having, for example, from 1 to 18 carbon atoms). More preferably, these reactive functional groups are hydroxyl groups.
• the resin used is preferably a vinylester resin of the epoxy type, also called "epoxyvinylester".
• Epoxy vinyl ester resins are well known to those skilled in the art, they have been described in numerous works, in particular in patent documents EP-AI 074,369, US-A-6,329,475 or WO-A-84/00170. It is more preferable to use an epoxyvinylester resin which, at least in part, is based (that is to say, grafted onto a structure of the type) novolak (also called phenoplast) and / or bisphenolic, that is to say a novolac, bisphenolic, or novolac and bisphenolic resin.
• a novolac-based epoxyvinylester resin (part in square brackets of formula I below) for example responds, in known manner, to the formula (n typically less than 10, for example from 1 to 5):
• a bisphenol A epoxyvinylester resin (part in square brackets of the formula II below) for example meets the formula (the "A" recalling that the product is manufactured using acetone) (n typically less than 10 for example from 1 to 5):
• the -OH groups of these resins are capable of reacting with the isocyanate groups (-NCO) of the polyisocyanate compound to form urethane bonds.
• an epoxyvinylester resin of the kolaole and bisphenolic type has shown excellent results, for example the vinylester resin "ATLAC 590" from DSM (diluted with about 40% styrene); such epoxyvinylester resins are available from other manufacturers such as Dow, Reichhold, Cray Valley, UCB.
• the adhesive or primary adhesion composition according to the invention may advantageously comprise a certain number of additives intended to improve its properties of use.
• the viscosity of the latter may for example be adjusted the possible solvent level of the polyester or vinylester resin, or be used a photoinitiator. It is preferred to use a solvent of the resin, at a preferential rate of between 5 and 15% (% total weight of resin and its associated solvent).
• a flexibilizing agent also called “chain extender” intended to make the composition more flexible once polymerized, in particular to significantly increase its elongation at break.
• a low molecular weight diene elastomer for example a polybutadiene, more preferably a vinylester or polyester end-chain functionalized, such an elastomer having a weight-average molecular weight (denoted Mw) more preferably comprised between 2000 and 4000 g. / mol.
• the weight ratio of the chain extender to the resin in the dry state is preferably between 0 and 1.5, more preferably between 0.8 and 1.4.
• the weight ratio polyisocyanate compound on resin in the dry state is preferably between 0.5 and 2.0, more preferably between 1.0 and 1.8, such a ratio being calculated on a molar basis polyisocyanate TDI (molar mass equal to about 174 g, 2 -NCO groups per mole).
• the weight ratio of the polyisocyanate compound to the resin in the dry state is preferably between 0.5 (M / 174) (2 / N) and 2.0 (M / 174) (2 / N). , more preferably between 1.0 (M / 174) (2 / N) and 1.8 (M / 174) (2 / N), M being the molar mass and N the number of groups (or equivalents) -NCO by mole of the polyisocyanate compound.
• M being the molar mass
• N the number of groups (or equivalents) -NCO by mole of the polyisocyanate compound.
• the ratio (in number) -NCO / functional groups of the resin, plus particularly -NCO / -OH, is more preferably greater than 3, for example typically between 3 and 8.
• the polyisocyanate compound and the resin described above, as well as any other additives are mixed until a homogeneous composition is obtained. Generally, a few seconds to a few minutes are enough.
• the period of use of the adhesion primer is preferably quite short, for example from a few minutes to a few tens of minutes during storage in the open air and at 20 ° C., for several hours at a lower temperature and under low humidity.
• the polyurethane covered with the adhesion primer and then baked so-called “pre-adhesive" polyurethane
• any secondary adhesion or hereinafter “secondary”
• diene elastomer which by definition is capable of binding, for example by chemical reaction or by means of a crosslinking agent, on the one hand to the diene elastomer, on the other hand to the vinylester or polyester resin of the primary adhesion.
• a specific secondary adhesion is used, hereinafter also referred to as "diene glue", which has the characteristic of comprising on the one hand a diene elastomer and on the other hand an additional compound capable of to bind, for example by chemical reaction or via a crosslinking agent, to the vinylester or polyester resin of the adhesion primer.
• This additional compound preferably consists of a polyester or vinylester resin.
• this resin is itself, advantageously and preferably, a vinyl ester resin, epoxy vinyl ester resin including a 'based novolak and / or bisphenolic preferably as used in the adhesion primer.
• the diene elastomer is a polyvinylpyridine-styrene-butadiene elastomer (abbreviated "p-VSBR").
• a p-VSBR elastomer consists in a known manner of a polyyinylpyridine coupled to an SBR diene elastomer (styrene-butadiene rubber), corresponding to the general formula:
• It is a polymer having a very high molecular weight, preferably 500,000 to 1,000,000 g / mol. It is generally commercially available in the form of a latex (dilute basic aqueous phase emulsion), for example at a level of about 40% by weight of polymer.
• a latex dilute basic aqueous phase emulsion
• the level of p-VSBR be between 10% and 40% and that of the resin be between 40% and 80% (% by weight of adhesive in the "dry" state). That is to say without any solvent - excluded the solvent of the resin itself - nor water). More preferably, the level of p-VSBR is between 15% and 30% (for example between 15% and 25%) and the resin content is between 50% and 75% (for example between 60% and 75%). .
• This diene adhesive crosslinkable with sulfur thanks to the presence of the diene elastomer, in particular p-VSBR, is capable of ensuring the direct bonding of the pre-adhesive polyurethane to a composition of diene elastomer in the green state.
• the diene adhesive described above can have a relatively high viscosity, which can make its industrial implementation difficult.
• the viscosity is preferably reduced by adding a solvent of the resin, more preferably styrene, at a level preferably comprised between 0% and 40% (% by weight of final glue, that is to say say ready for use). More preferably, the solvent content is adjusted between 5% and 35%, in order to give adequate fluidity to the glue; below 5%, this fluidity may be insufficient depending on the industrial application targeted; beyond 35% or 40%, we is exposed to a risk of fluidity too high (risk of occurrence of spurious spin phenomena).
• a solvent level more preferably between 10% and 30%, more preferably between 10% and 20%.
• the diene adhesive does not require the presence of water, that is why it can be described as “no -aqueuse "although it can withstand without damage the presence of water in small amounts, the latter being preferably present at a rate of less than 5%, more preferably less than 2% (% by weight of final glue, ready to employment).
• the above secondary may advantageously comprise known accelerators and activators for the polymerization of the resin itself, such as cobalt II salts (for example 2-ethylhexanoate). cobalt), dimethylaniline (DMA) or diethylaniline (DEA), N 3 N-dimethylacetoacetamide (DMAA) or N, N-diethylacetoacetamide (DEAA), this at levels typically between 0.3 and 3.0 phr (parts by weight for one hundred parts of elastomer).
• cobalt II salts for example 2-ethylhexanoate
• DMA dimethylaniline
• DEA diethylaniline
• DMAA N 3 N-dimethylacetoacetamide
• DEAA N-diethylacetoacetamide
• the secondary may also comprise all or part of the additives usually used in adhesive compositions for bonding diene rubbers, such as reinforcing fillers such as carbon black or silica, anti-aging agents, for example antioxidants, plasticizers coupling agents, a crosslinking system based on either sulfur, or sulfur and / or peroxide donors, accelerators, vulcanization activators or retarders, methylene acceptors and donors (such as HMT or H3M) reinforcing resins such as resorcinol, bismaleimide, tackifying resins.
• reinforcing fillers such as carbon black or silica
• anti-aging agents for example antioxidants
• plasticizers coupling agents for example antioxidants
• a crosslinking system based on either sulfur, or sulfur and / or peroxide donors
• accelerators, vulcanization activators or retarders such as HMT or H3M
• reinforcing resins such as resorcinol, bismaleimide, tackifying resins
• the crosslinking system itself is preferably based on sulfur and a primary vulcanization accelerator, in particular a sulfenamide type accelerator.
• a primary vulcanization accelerator in particular a sulfenamide type accelerator.
• various secondary accelerators or known vulcanization activators such as zinc oxide, stearic acid, etc., may be added.
• Sulfur is used at a preferred level of between 0.5 and 10 phr, more preferably between 0.5 and 5.0 phr.
• the primary vulcanization accelerator is used at a preferred level of between 0.5 and 10 phr, more preferably between 0.5 and 5.0 phr.
• the diene adhesive described above can be prepared starting, for example, from a diene elastomer latex, in particular p-VSBR, by extracting the water from the latex and then incorporating the resin in solution in styrene into the elastomer.
• the step of extracting the water from the latex may be carried out by any means known to those skilled in the art, in particular by the action of a coagulating agent such as a salt, a base or an acid, for example by coagulation in an acetone-water mixture in an acid medium (eg HCl) and then neutralization (with water or by the action of a weak base), followed by a filtrate recovery step and drying (evaporation of the solvent).
• a coagulating agent such as a salt, a base or an acid
• the extraction of the water from the latex can also be carried out by azeotropic distillation, in which case the elastomer is dissolved in an organic solvent such as toluene and an additional step can be added in order to carry out a final extraction, at less partial, organic solvent (s) used (s).
• organic solvent such as toluene
• additives of the diene glue in particular its crosslinking system, are added.
• these additives are themselves presented in solution or in suspension (for example carbon black and ZnO which are insoluble) in a suitable organic liquid, preferably the same as that used, if appropriate, for azeotropic distillation step.
• the weight ratio resin / diene elastomer in particular resin / p-VSBR, is preferably chosen between 1 and 8. More preferably, it is between 1.5 and 7.0, for example between 2.0 and 6.0. A value within a range of 3 to 5 (for example, close to or equal to 4) has proved optimal in a large number of cases.
• the process according to the invention for adhering a baked (polymerized) polyurethane to a raw diene elastomer composition, comprises the following steps: applying the previously defined adhesion primer to the solid polyurethane; polymerizing the adhesion primer and the polyurethane thus covered with its adhesion primer; then deposit on the polyurethane thus pre-adherited adhesion secondary previously defined; putting the diene elastomer composition in the green state in contact with the polyurethane thus glued; - Cook the whole, preferably under pressure.
• the polyurethane must be in an at least partially polymerized (ie "prepolymerized”) state, that is, sufficiently solid to receive the primary adhesion, moreover in the form that it will have essentially (to any subsequent cutting operations near) in the final composite.
• prepolymerized at least partially polymerized
• the polyurethane may be available as such in the solid state or prepolymerized, or prepared just before implementation of the first step of the above process, in a manner well known to those skilled in the art from a urethane prepolymer.
• the duration of this prepolymerization step may vary according to the particular conditions adopted, typically from a few minutes to a few hours (for example between 30 min and 3 h) for a temperature preferably between 80 0 C and 12O 0 C (for example about 110 ° C.), it being understood that the use of a polymerization catalyst (for example a tertiary amine or a C 18 fatty acid) may make it possible to reduce the duration of such a step to only a few minutes.
• a polymerization catalyst for example a tertiary amine or a C 18 fatty acid
• urethane prepolymers examples include Adiprene® (L series) and Vibrathane® products from Crompton, Baytec® from Bayer.
• Urethane prepolymer curing agents are well known.
• polyols are diols such as, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,3-butanediol or 1,4-butanediol, or triols such as, for example, glycerol; as amino compounds, mention may be made, for example, of diphenylmethane compounds such as 3,3'-dichloro-4,4'-diaminodiphenylmethane (abbreviated "MOCA"), 2,2'-dichloro-3,3 ', 5,5'-tetraethyl-4,4'-diaminodiphenylmethane (abbreviated "MCDEA”), toluene diamines such as 3,5-dimethylthio-2,4-toluene diamine, 3,5-diethyl-2,4 toluene diamine, benzoates such as trimethylene glycol-
• additives such as dye, filler, dispersant, antioxidant, or other stabilizer, could be added at the same time as the hardener.
• the adhesion primer is applied to the at least prepolymerized polyurethane by any known means such as spraying, bathing, or by brush or spatula application.
• This step of application of the adhesion primer may advantageously be preceded by a preliminary step of preparation, activation of the surface of the polyurethane, in particular by ime mechanical action (for example a brushing) or chemical, provided however that this activation, especially when it is of a chemical nature, does not interfere with the effectiveness of the adhesive system of the invention.
• a surface preparation can promote the mechanical anchoring of the adhesion primer and in particular avoid too rapid evaporation of the polyisocyanate compound on the surface of the polyurethane.
• the following step of polymerization of the adhesion primer and of the polyurethane thus covered with its primer is preferably carried out by heat treatment in a temperature range of more preferably between 90 ° C. and 120 ° C. (for example between 100 ° C. and 100 ° C.). 115 0 C) so as not to degrade the mechanical properties of the product. More preferably still, this firing is carried out under pressure, for example in an autoclave under a pressure of between 4 and 8 bar, in order to avoid a possible bubbling of the polyisocyanate which, if it is liquid (in the case of TDI), may have a tendency to to evaporate.
• the primer thus deposited and baked on the pre-adhered polyurethane is very stable over time and could be stored, preferably protected from various pollution such as dust, before use of the secondary adhesion. But it is generally preferred to implement the next step immediately after.
• the secondary adhesion previously described is then deposited by any known means (for example brush, spatula, spraying), then or covers the whole of the diene elastomer composition in the raw state. .
• the final step is then to cook all, preferably under pressure, to allow the crosslinking of the secondary and the adhesion primer, as well as the complete vulcanization of the rubber.
• the invention applies to any type of composite that can be obtained by the method described above, comprising at least a first portion of integral polyurethane a second part of diene rubber composition via an adhesive interphase, said adhesive interphase being based on:
• Said secondary adhesion is preferably an adhesive based on a diene elastomer and an additional compound capable of bonding to the vinylester or polyester resin of the adhesion primer. More preferably, said diene elastomer is a polyvinylpyridine-styrene-butadiene (abbreviated "p-VSBR").
• the secondary adhesion compound capable of bonding to the vinylester or polyester resin of the primer itself consists of a vinylester or polyester resin.
• the use of an identical resin in the primary and secondary, especially an epoxyvinylester-type resin, is particularly advantageous, the adhesive interphase of the composite being in this case simply based on the three essential constituents
• the thickness of the adhesive interphase, after firing is between 0.02 and 0.50 mm, more preferably between 0.02 and 0.10 mm.
• interphase comprising the mixture and / or the reaction product in situ of the various basic constituents used for this interphase, some of them, in particular primary 30 and secondary adhesion, being intended to react with each other or with their surrounding chemical environment, at least in part, during the various phases of manufacture of composites or finished articles comprising such composites, in particular during the step of final cooking.
• diene elastomer or indistinctly rubber is meant in known manner an elastomer derived at least in part (ie, a homopolymer or a copolymer) of monomers dienes that is to say monomers carrying two double bonds carbon-carbon, conjugated or not.
• the diene elastomer used is preferably chosen from the group consisting of polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), butadiene-styrene copolymers (SBR) and isoprene copolymers.
• BIR butadiene
• SIR isoprene-styrene copolymers
• SBIR butadiene-styrene-isoprene copolymers
• a preferred embodiment consists in using an "isoprene” elastomer, that is to say a homopolymer or copolymer of isoprene, in other words a diene elastomer chosen from the group consisting of natural rubber (NR). , the synthetic polyisoprenes (IR), the various isoprene copolymers and the mixtures of these elastomers.
• isoprene elastomer
• NR natural rubber
• IR synthetic polyisoprenes
• the isoprene elastomer is preferably natural rubber or synthetic polyisoprene of the cis-1,4 type.
• synthetic polyisoprenes are used preferably polyisoprenes having a content (mol%) of cis-1,4 linkages greater than 90%, more • preferably still greater than 98%.
• the diene elastomer may consist, in whole or in part, of another diene elastomer such as, for example, an SBR elastomer used in or with another elastomer, for example type BR.
• Said rubber composition may also comprise all or part of the additives normally used in rubber matrices intended for the manufacture of tires, such as, for example, reinforcing fillers such as carbon black or inorganic fillers such as silica, coupling agents for inorganic filler, anti-aging agents, antioxidants, plasticizing agents or extension oils, whether the latter are of aromatic or non-aromatic nature (in particular very low or non-aromatic oils, for example of the naphthenic or paraffinic, high or preferably low viscosity, MES or TDAE oils, plasticizing resins with high Tg greater than 30 ° C), agents facilitating the implementation (processability) of the compositions in the green state, resins tackifying agents, a crosslinking system based on either sulfur or sulfur and / or peroxide donors, accelerators rs, vulcanization activators or retarders, anti-eversion agents, methylene acceptors and donors such as, for example, HMT (hexamethylenetetramine) or H3M
• the invention also relates to any tire for a road vehicle, whether of the pneumatic or non-pneumatic type, in which at least one diene elastomer structure part is cooperating with or associated with at least one polyurethane structure part.
• the invention is particularly applicable to a tire (Le., Conventional) of which at least a part of the structure, zone bead, sidewall or crown of the tire, comprises a polyurethane element, in particular with a high modulus in extension, at contact of another diene elastomer element.
• the invention also applies particularly to a non-pneumatic tire as described for example in the aforementioned EP-AI 359 028 patent application, having a flexible bearing structure extending circumferentially about an axis of rotation, a strip of bearing at the radially outer periphery of the . supporting structure, and at least one attachment zone, radially on the side of the axis of rotation, for the immobilization of said supporting structure to a wheel disk, the bearing structure comprising (reference to the appended figure):
• a plurality of support elements 2 extending essentially transversely, of which a first part is arranged at least facing a part of the tread
• said diene elastomer inter-connection structure 3 being connected to the polyurethane elastic joints 4 by means of an adhesive interphase based on the polyisocyanate compound, the polyester or vinylester resin and the p-VSBR elastomer previously described.
• the attached figure illustrates a particular embodiment of such a bandage wherein the bandage profile delimits a toroidal internal cavity of oval section.
• the tire 1 comprises two axially separable fixing regions 11, two sidewalls 12 and a tread 13.
• the tread 13 has several parallel ribs, but this aspect is of course in no way limiting.
• the flanks 12 are rounded and occupy most of the radial height of the tire 1.
• the bearing structure comprises support elements 2 also called radial hoops. These support elements 2 are
• the hoops 2 may comprise a stack of composite material blades, flexible, superimposed with interposition of a layer of diene elastomer or polyurethane between said blades.
• the bundle of blades thus bonded to each other forms a beam capable of being biased in flexion.
• This aspect of the constitution of the laminate is however not limiting.
• the bearing structure also comprises an interconnection structure 3 between the support elements 2, preferably arranged radially between the tread 13 and the support elements 2.
• the interconnection structure 3 is capable of distributing a circumferential radial stress between several support members 2, while allowing displacement differences between adjacent support members.
• the interconnection structure 3 preferably comprises a reinforcement oriented substantially circumferentially, for example a monofilament reinforcement 30 embedded in an elastomeric matrix 31, wound in several places to surround all the support elements 2 opposite the tread 13, itself being preferably of diene rubber.
• the monofilament reinforcement turns 30 are in this particular case arranged radially over a layer 32 of an elastomeric material.
• the monofilament reinforcement 30 is wound substantially circumferentially, that is to say at an angle close to 0 ° with respect to a plane perpendicular to the axis. It may be a winding of said monofilament reinforcement 30 according to the desired number of turns or, which is equivalent, it may be monofilament rings in desired number. Note that one could alternatively monofilament reinforcement 30, use many cables among those commonly used as reinforcement zero degrees disposed within the tread of conventional tires. It would also be possible to use a reinforcement in the form of a blade or a ribbon for example made of reinforced composite material, rather than a monofilament reinforcement. Again, the blade or ribbon is wound according to the desired number of turns or used in the form of rings used in a desired number.
• each support element 2 and the interconnection structure 3 are connected by elastic joints 4.
• Each support element 2 is radially surmounted by such an elastic articulation 4, which ensures the mechanical connection between the elements. 2 and the interconnection structure 3, the forces transmitted to each other passing through said elastic joints 4.
• said support elements 2 are axially continuous with respect to the tread and beyond, to the attachment zones 11.
• each support element 2 comprises a median portion 25 substantially corresponding to the width of the interconnection structure 3. This is how is realized, in the non-limiting example illustrating the invention, said first part (of each support element) arranged at least facing a portion of the tread.
• the interconnection structure 3 occupies substantially the entire width (w) of the tread 13.
• each elastic articulation 4 makes it possible to connect the middle portion 25 of the support elements 2 to the interconnection structure 3.
• each support member 2 comprises, on each side of the tire, a lateral portion 26 extending in the sidewall 12 and joining the fastening zone 11. This is how is achieved, in the non-limiting example illustrating the invention, said other portion (of each support member) disposed beyond the tread, where the support members are bent when the bandage is loaded.
• the bandage 1 may or may not include an outer skin 120 giving it a uniform appearance as seen in the right part of the figure ; this skin 120, not designed to transmit forces or between support elements or between support elements and interconnection structure, simply covers all of the support elements 2, from outside thereof. There could also be a material between the support members 2, partially or completely filling the space between two adjacent support members 2.
• all or part of the elastic joints 4, preferably each of them, is made of polyurethane and the bond between the polyurethane and the diene rubber of the interconnection structure 3 is ensured by means of adhesive system according to the invention.
• TDI TDI-co-diol
• AAC 590 AZAC 590 having about 10% by weight of residual styrene as the solvent of the resin (% by total weight of resin and styrene).
• the TDI weight ratio on resin in the dry state is therefore of the order of 1.55.
• the ratio of functional groups -NCO / -OH is here greater than 3 (in fact close to 5, depending on the degree of polymerization estimated of the particular epoxyvinylester resin used here); in others
• the adhesion primer contains about five times more isocyanate groups than hydroxyl groups.
• this example starts with a latex of p-VSBR elastomer from which the water is extracted by coagulation, and then is incorporated in the elastomer a vinylester resin in solution in styrene, at a weight ratio (resin / elastomer) equal to about 4.
• a last wash can be carried out for example with a water / acetone mixture.
• the polymer can be treated with an apparatus for spraying the polymer into very fine particles.
• the polymer is filtered and dried for 12 hours, under vacuum, at a temperature of 60 ° C.
• the 20 g of p-VSBR thus obtained are added to 125 g of epoxyvinylester resin ("ATLAC 590" - 80 g of dry vinylester for 45 g of styrene) and allowed to stand overnight. The polymer swells by absorbing the resin.
• epoxyvinylester resin "ATLAC 590" - 80 g of dry vinylester for 45 g of styrene
• the remainder of the components (black, vulcanizing agents, etc.) are then added according to the detailed formulation indicated in the attached Table 1 (the amounts in phr are parts by weight per 100 parts of p-VSBR elastomer), directly in an external mixer (cylinder tool), at room temperature, and the mixture is mixed until a homogeneous glue, black runner.
• the diene adhesive thus prepared advantageously contains less than 1% water (% by weight of final composition, ready for use).
• the vinyl ester resin in order to increase the viscosity of the diene glue but also to reduce the amount of solvent released during the subsequent firing of the composite in press, it is possible to dry the vinyl ester resin under a high vacuum before mixing it with the elastomer, for example up to a residual styrene content of between 10% and 15%.
• this diene adhesive contains a certain residual amount of solvent, it does not have the usual disadvantages of solvent-based adhesives because styrene reacts completely when the diene adhesive is used by taking part in the polymerization. of the latter; it does not have to be evaporated.
• the Adiprene® LF930A product from Crompton consisting of a polyether-TDI prepolymer
• the latter is cast in a mold of predetermined shape (imposed by the shape of the target composite) in the presence of its curing agent (MCDEA), and subjected to a prepolymerization of 45 min at a temperature of 110 ° C, to make it solid in this predefined form (here a simple strip of polyurethane having after cutting a width of 25 mm, length of at least 150 mm and thickness of about 2 mm).
• the adhesion primer is applied with a brush to the polyurethane layer thus prepolymerized, in a layer of thickness. equal to about 50 to 100 ⁇ m.
• the polyurethane and the adhesion primer which covers it are then polymerized by baking for 24 hours at 110 ° C., in an autoclave, under a pressure of 6 bar.
• the whole is covered with a layer of raw diene rubber composition (strip of the same dimensions as the first polyurethane layer), the formulation of which corresponds to a known rubber composition based on natural rubber and carbon black. which can be used in particular as reinforcement reinforcing calendering gum of a conventional tire carcass; two different formulations (expressed in phr) are given as examples in Table 2.
• the assembly is finally cooked in a press, for example at 165 ° C. for 55 min, under a pressure of 20 bar, allowing the end of the polymerization of the secondary adhesion on the primer and on the rubber, as well as the vulcanization or baking. rubber.
• the composite thus obtained is then subjected to a known peel test as described in International Standard ISO 8510-1: 1990 (F), consisting of pulling apart the respective two parts of polyurethane and diene rubber, the test being carried out at ambient temperature (23 ° C.) and at elevated temperature (90 ° C.).
• F International Standard ISO 8510-1: 1990
• the loss of tearing force between 23 0 C and 90-100 0 C is here only about 35% while it is for example greater than 80% in the document US 4 942 093 cited above describing the use a liquid polyurethane glue that has already been improved compared to conventional commercial glues for bonding polyurethane and raw rubber.
• the composite of the invention has, during peeling, a break not in the adhesive interphase, but in the elastomer layer, which illustrates a very high adhesion level cold and hot .
• the adhesive composition according to the invention is particularly suitable, as adhesion primer, for bonding a polyurethane baked with raw rubber, its potential industrial application is broad and can extend to products, in particular polymers or elastomers, other than polyurethane, since these products have the functionalities capable of reacting with such an adhesive composition.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Health & Medical Sciences (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Lining Or Joining Of Plastics Or The Like (AREA)
• Tires In General (AREA)
• Laminated Bodies (AREA)
• Paints Or Removers (AREA)
• Polyurethanes Or Polyureas (AREA)
• Steroid Compounds (AREA)
• Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
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