Improved method for gluing one or more strands of glass resin composite GRC

Abstract

The present invention relates to a method for gluing one or more strands of glass resin composite material GRC, characterized in that it comprises the following steps: a) a step of pre-bonding one or more strands of GRC by immersing the one or more strands of GRC in a first water bath comprising a composition, the composition is based on:-an epoxy compound; and-a blocked diisocyanate compound; b) a step of depositing on the one or more strands of GRC by immersing the one or more strands of GRC in a second bath comprising an aqueous binder composition based on:-at least one compound A1 comprising at least one aldehyde functional group; -at least one phenol A21; -at least one unsaturated elastomer latex, said unsaturated elastomer latex comprising at least one elastomer, the elastomer is selected from the group consisting of butadiene copolymers, styrene-butadiene copolymers, vinylpyridine-styrene-butadiene terpolymers, natural rubbers other than chlorinated natural rubbers, and mixtures of these elastomers; the aqueous adhesive composition in the second bath has a blocked diisocyanate content strictly less than 0.50% by weight.

Description

Technical Field

[0001] The field of the invention is that of glass reinforced plastics (abbreviated GRP) and of adhesive compositions or "glue" intended to bond these elements to elastomeric substrates, such as are commonly used in semi-finished elastomeric articles or products or in the tyre or conveyor belt field.

[0002] The invention more particularly relates to an improved method for sizing a strand or strands of glass reinforced plastic (GRP), an elastomeric composite comprising such sized GRP and a tyre reinforced by such an elastomeric composite. Background Art

[0003] Known from the prior art is a conventional method for gluing glass reinforced plastics, described in application WO2016116457, in which it is generally known to pre-bond them in an aqueous solution, usually based on epoxy resins and isocyanates, in a first bath and then to glue the glass reinforced plastics in a second bath using a conventional aqueous adhesive composition, for example an adhesive composition known under the name "RFL" (resorcinol-formaldehyde latex), as described in EP2006341, mixed with an aqueous solution based on blocked diisocyanates and then with an elastomeric matrix having a 100% vinylpyridine latex phase. Blocked diisocyanates are added to the adhesive composition at a weight content of 9% to improve the adhesion.

[0004] Also known from the prior art is the method for bonding polyesters described in application WO2021117519, but the bonding mechanism between the adhesive composition and the polyester is different from the bonding mechanism between the adhesive composition and the glass reinforced plastic. In the bonding mechanism between the polyester and the adhesive composition, covalent bonds and secondary chemical bonds are formed between the polyester and the adhesive system. The polarity of polyester is not strong, so a pre-bonding step is required to achieve bonding. In the bonding mechanism between the glass reinforced plastic and the adhesive composition described in application WO2008061544, the glass reinforced plastic has been cross-linked in advance, and the chemical function of the surface is different from the chemical function used between the polyester and the adhesive composition, so a pre-bonding treatment is not necessarily required.

[0005] Therefore, designers of elastomeric articles, in particular tire manufacturers, are now aiming to find new simple ways to achieve satisfactory adhesion of glass reinforced plastics (GRP) to elastomeric substrates without the need to use adhesive compositions in combination with products that have a negative impact on the environment. Furthermore, it is desirable that this adhesion is relatively high initially (i.e. after cooling after curing) and that this adhesion is not easily degraded under humid conditions.

[0006] During the research process, the applicant discovered a method that can achieve the above-mentioned goals. Summary of the invention

[0007] The present invention therefore relates to a method for gluing one or more strands of glass reinforced plastic (abbreviated to GRP), characterised in that the method comprises the following steps:

[0008] a) carrying out a step of pre-bonding one or more strands of GRP plastic by immersing said strand or strands in a first aqueous bath comprising a composition based on:

[0009] - epoxy compounds; and

[0010] - blocked diisocyanate compounds;

[0011] b) carrying out a step of depositing on the GRP plastic strands by immersing the GRP plastic strands in a second bath comprising an aqueous binder composition based on:

[0012] - at least one compound A1 comprising at least one aldehyde function;

[0013] - at least one phenol A21;

[0014] at least one unsaturated elastomeric latex comprising at least one elastomer chosen from butadiene copolymers, styrene-butadiene copolymers, vinylpyridine-styrene-butadiene terpolymers, natural rubbers other than chlorinated natural rubbers and mixtures of these elastomers;

[0015] The content of the blocked diisocyanate compound in the aqueous adhesive composition of the second bath is strictly less than 0.50% by weight.

[0016] Therefore, the applicant assumes that the pre-bonding step is an essential step, on the one hand to maintain a good bonding level initially, and on the other hand to ensure the resistance of the bonding interface to humid conditions and / or temperature, which, however, does not require the use of blocked diisocyanates in the aqueous adhesive composition, and it is therefore desirable to reduce the amount of blocked diisocyanates used.

[0017] The present invention also relates to an elastomeric composite material reinforced by at least one or more sized glass reinforced plastic (GRP) strands embedded in an elastomeric matrix, wherein the sized glass reinforced plastic (GRP) strands are obtained by a method as described above.

[0018] The composite material according to the invention produced in this way can be used advantageously in particular for reinforcing pneumatic or non-pneumatic tires of all types of vehicles, in particular passenger vehicles or industrial vehicles (for example heavy vehicles or civil engineering vehicles), aircraft and other transport or handling vehicles.

[0019] The present invention also relates to a tire comprising the elastomeric composite material as described above.

[0020] The present invention also relates to a conveyor belt comprising the elastomeric composite material as described above.

[0021] The process according to the invention allows a significant increase in the service life of the composite materials according to the invention and thus of the tires or conveyor belts comprising them, especially under wet conditions, which demonstrates the resistance of the resulting adhesive interface.

[0022] Any numerical interval represented by the expression "between a and b" means a numerical range extending from greater than a to less than b (i.e., excluding the endpoints a and b), while any numerical interval represented by the expression "a to b" means a numerical range extending from a to b (i.e., including the strict endpoints a and b).

[0023] In the context of the present invention, the carbon products mentioned in the description can be of fossil origin or of bio-based origin. In the case of bio-based origin, they can be partially or completely produced from biomass, or obtained from renewable raw materials produced from biomass.

[0024] In the present specification, unless otherwise expressly indicated, all percentages (%) shown are % by weight.

[0025] The term "elastomeric composition" refers to a composition comprising at least one elastomer (or equivalently rubber) and at least one other component.

[0026] By "diene" elastomer (or equivalent rubber) is understood an elastomer obtained at least in part (ie homopolymer or copolymer) from diene monomers (ie monomers bearing two conjugated or non-conjugated carbon-carbon double bonds). By "isoprene elastomer" is understood an isoprene homopolymer or copolymer, in other words a diene elastomer chosen from natural rubber (NR), synthetic polyisoprenes (IR), various isoprene copolymers and mixtures of these elastomers.

[0027] The term "elastomeric matrix" refers to a matrix that behaves like an elastomeric body.

[0028] The term "meta-positioned relative to one another" means that the hydroxyl functional groups are carried by carbons of the aromatic ring which are separated from one another by a single other carbon of the aromatic ring.

[0029] The term "ortho to a functional group" refers to the position occupied by the carbon of the aromatic ring that is immediately adjacent to the carbon of the aromatic ring bearing the functional group.

[0030] The term "unit" of a ring refers to the constituent atoms of the ring backbone. Thus, for example, a benzene ring contains six units, each consisting of one carbon atom. In another example, a furan ring contains five units, four of which are each composed of one carbon atom, and the remaining unit is composed of one oxygen atom.

[0031] "CHO" represents an aldehyde functional group.

[0032] "CH2OH" represents a hydroxymethyl functional group.

[0033] The term "aromatic polyphenols" refers to aromatic compounds comprising at least one benzene ring with more than one hydroxyl functional group.

[0034] The term "resin based" is understood to mean that the resin comprises a mixture and / or reaction product of the various essential components as defined above for the resin, and that the resin is based solely on the components of the resin. Thus, the essential components are reactants that are intended to react together during the final condensation of the resin, and are not reactants that are intended to react together to form these essential components.

[0035] According to the present invention, the basic component of the aqueous adhesive composition thus comprises at least one compound A1 and at least one phenol A21. In one embodiment, the basic component may comprise other additional components different from compound A1 and phenol A21. In another embodiment, the basic component consists of at least one compound A1 and at least one phenol A21.

[0036] Preferably, in embodiments where the base component comprises other additional components, these other additional components are free of formaldehyde and / or free of methylene donors selected from the group consisting of hexamethylenetetramine (HMT), hexamethoxymethylmelamine (H3M), hexaethoxymethylmelamine, dodecyloxymethylpyridinium chloride, ethoxymethylpyridinium chloride, polymers of hexamethoxymethylmelamine with trioxane of formaldehyde, hexa(methoxymethyl)melamine, N,N',N"-trimethyl-N,N',N"-trimethylolmelamine, hexamethylolmelamine, N-methylolmelamine, N,N'-dimethylolmelamine, N,N',N"-tri(methoxymethyl)melamine and N,N',N"-tributyl-N,N',N"-trimethylolmelamine. More advantageously, these other additional components are free of formaldehyde and free of the methylene donors described in this paragraph.

[0037] More preferably, in the embodiment where the base component comprises other additional components, these other additional components are free of formaldehyde and / or free of methylene donors selected from the group consisting of hexamethylenetetramine, hexaethoxymethylmelamine, hexamethoxymethylmelamine, dodecyloxymethylpyridinium chloride, ethoxymethylpyridinium chloride, hexamethoxymethylmelamine of trioxane and N-substituted oxymethylmelamine corresponding to the following general formula:

[0038]

[0039] Wherein Q represents an alkyl group containing 1 to 8 carbon atoms; F1, F2, F3, F4 and F5 are independently selected from hydrogen atoms, alkyl groups containing 1 to 8 carbon atoms, groups -CH2OQ and condensation products thereof. More advantageously, these other additional components do not contain formaldehyde and do not contain the methylene donors described in this paragraph.

[0040] Even more preferably, in embodiments where the base component comprises other additional components, these other additional components are formaldehyde-free and / or methylene donor-free. Even more advantageously, these other additional components are formaldehyde-free and methylene donor-free.

[0041] The term "free of formaldehyde or free of methylene donors" means that the total weight content of formaldehyde or methylene donors belonging to the above groups is less than or equal to 10%, preferably less than or equal to 5%, more preferably less than or equal to 2%, and even more preferably less than or equal to 1%, relative to the total weight of Compound A1 in the basic component.

[0042] The term "free of formaldehyde or free of methylene donors" means that the total weight content of formaldehyde and methylene donors belonging to the above-mentioned groups is less than or equal to 10%, preferably less than or equal to 5%, more preferably less than or equal to 2%, and even more preferably less than or equal to 1%, relative to the total weight of Compound A1 in the basic component.

[0043] The term "strands of glass reinforced plastic GRP" refers to composite material reinforcements based on GRP type monofilaments comprising continuous unidirectional multifilament glass fibers embedded in a thermosetting resin and which can be used in particular as reinforcing elements for tires.

[0044] Method according to the invention

[0045] A) Pre-bonding step

[0046] Pre-bonding of the GRP strands is carried out in an aqueous solution in a first bath based on epoxy resin and blocked diisocyanate.

[0047] Advantageously, the epoxy compound is chosen from diethylene glycol diglycidyl ether, polyethylene diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, sorbitol polyglycidyl ether or isosorbide diglycidyl ether; preferably it is polyglycerol polyglycidyl ether.

[0048] Advantageously, the blocked diisocyanate compound is selected from diphenylmethane diisocyanate or polyphenylene polymethylene polyisocyanate, preferably N,N′-(methylenedi-p-phenylene)bis[hexahydro-2-oxo-1H-azepine-1-carboxamide 4,4′-diisocyanate.

[0049] Advantageously, this pre-bonding step is followed by a step of drying the GRP plastic at a temperature greater than or equal to 120° C. for at least 5 seconds, followed by a heat treatment at a temperature greater than or equal to 180° C. for at least 5 seconds.

[0050] B) Step of depositing the aqueous adhesive composition

[0051] An aqueous adhesive composition is then deposited onto the pre-bonded GRP strands.

[0052] According to the invention, the basic component of the resin thus comprises at least one compound A1 and at least one phenol A2. In one embodiment, the basic component may comprise other additional components different from compound A1 and phenol A2. In another embodiment, the basic component consists of at least one compound A1 and at least one phenol A2.

[0053] According to the present invention, the aqueous adhesive composition is prepared so that the weight content of the blocked diisocyanate in the aqueous adhesive composition is strictly less than or equal to 0.50%.

[0054] Preferably, the weight content of the blocked diisocyanate compound in the aqueous adhesive composition of the second bath is strictly less than 0.40%, preferably less than or equal to 0.30%, more preferably less than or equal to 0.20%, more preferably less than or equal to 0.10%, even more preferably less than or equal to 0.05%.

[0055] More preferably, the aqueous adhesive composition of the second bath does not contain blocked diisocyanate.

[0056] Compound A1

[0057] Another essential component of the adhesive composition is compound A1 which comprises at least one aldehyde function.

[0058] According to the invention, the resin is based on at least one (ie one or more) compound A1.

[0059] In a first embodiment, compound A1 is formaldehyde.

[0060] In a second embodiment, compound A1 comprises at least one aromatic ring which carries at least one aldehyde function.

[0061] More preferably, compound A1 carries at least two aldehyde functions.

[0062] Still more preferably, the aromatic ring of compound A1 carries two aldehyde functions.

[0063] In one embodiment, the aromatic ring of compound A1 is selected from a benzene ring and a furan ring; preferably, the aromatic ring of the aromatic aldehyde is a benzene ring.

[0064] Preferably, compound A1 is selected from 1,2-phthalaldehyde, 1,3-phthalaldehyde, 1,4-phthalaldehyde, 2-hydroxybenzene-1,3,5-tricarbaldehyde and mixtures of these compounds.

[0065] In a variant form of the second embodiment, compound A1 has the general formula (A):

[0066]

[0067] in:

[0068] X includes N, S or O,

[0069] R represents -H or -CHO.

[0070] Preferably, compound A1 has the general formula (A'):

[0071]

[0072] Wherein, X represents O.

[0073] Still more preferably, R represents -CHO.

[0074] According to a preferred embodiment, X represents O.

[0075] In one variant of the compound A1 of general formula (A), X represents O and R represents -H. The compound A1 used then has formula (Ba):

[0076]

[0077] In one variant of the aldehyde of general formula (A'), X represents O and R represents -H. The compound A1 used is then furfural and has formula (B'a):

[0078]

[0079] In another variant of the compound A1 of general formula (A), X represents O and R represents -CHO. The compound A1 used then has formula (Bb):

[0080]

[0081] In another variant of compound A1 of general formula (A'), X represents O and R represents -CHO. The compound A1 used is then 2,5-furandicarboxaldehyde and has formula (B'b):

[0082]

[0083] In another embodiment, X comprises N.

[0084] Preferably, compound A1 is selected from furfural, 2,5-furandicarboxaldehyde and mixtures of these compounds.

[0085] In one variant of compound A1 of general formula (A), X represents NH. The compound A12 used has formula (Ca):

[0086]

[0087] In one variant of compound A1 of general formula (A'), X represents NH. The compound A12 used has formula (C'a):

[0088]

[0089] Preferably, in a variant form of compound A12 having formula (C'a), R represents -CHO, the compound A12 obtained is 1H-pyrrole-2,5-dicarbaldehyde.

[0090] In another variant of compound A1 of general formula (A), X represents NT1, wherein T1 represents alkyl, aryl, arylalkyl, alkylaryl or cycloalkyl. The compound A12 used has formula (Cb):

[0091]

[0092] In another embodiment, X comprises S.

[0093] In one variant of compound A1 of general formula (A), X represents S. The compound A12 used has formula (Da):

[0094]

[0095] In one variant of compound A1 of general formula (A'), X represents S. The compound A12 used has formula (D'a):

[0096]

[0097] Preferably, in a variant of compound A1 of formula (IV'a), R represents -CHO, which is 2,5-thiophenedicarbaldehyde.

[0098] In another variant of the compound A1 of the general formula (A), X represents ST2, wherein T2 represents alkyl, aryl, arylalkyl, alkylaryl or cycloalkyl. The compound A12 used has the formula (Db):

[0099]

[0100] In another variant of the compound A1 of general formula (A), X represents T3-S-T2, wherein T2 and T3 independently represent alkyl, aryl, arylalkyl, alkylaryl or cycloalkyl. The compound A1 used has formula (Dc):

[0101]

[0102] In yet another variant of compound A1 of general formula (A), X represents S=O. The compound A12 used has formula (Dd):

[0103]

[0104] In yet another variant of the compound A1 of the general formula (A), X represents O=S=O. The compound A12 used has the formula (De):

[0105]

[0106] In the above embodiments, preferred are embodiments and variants in which X represents NH, S or O. In these embodiments and variants, R may represent -H or -CHO, and preferably R represents -CHO. In these embodiments and variants, on the aromatic ring (formula (A')), R is preferably located at position 5, and the -CHO group is preferably located at position 2.

[0107] Phenol A21

[0108] According to the invention, the resin is based on at least one (ie one or more) phenol A21.

[0109] Advantageously, the phenol A21 is chosen from:

[0110] an aromatic polyphenol A2 comprising at least one aromatic ring carrying at least two hydroxyl functions located in the meta position relative to one another, the two ortho positions of at least one hydroxyl function being unsubstituted;

[0111] an aromatic monophenol A2' comprising at least one six-membered aromatic ring carrying a single hydroxyl function,

[0112] The two ortho positions of the hydroxyl functional group are unsubstituted, or

[0113] At least one of the ortho and para positions of the hydroxyl functional group is unsubstituted;

[0114] - A mixture of A2 and A2'.

[0115] In one embodiment, the phenol is an aromatic polyphenol A2 comprising one or more aromatic rings. The aromatic polyphenol comprises at least one aromatic ring carrying at least two hydroxyl functions located in the meta position relative to each other, at least one hydroxyl function being unsubstituted in both ortho positions.

[0116] In another embodiment, the phenol is an aromatic monophenol A2' comprising at least one six-membered aromatic ring carrying a single hydroxyl function. On the aromatic monophenol, both ortho positions to the hydroxyl function are unsubstituted, or at least one ortho position to the hydroxyl function and the para position to the hydroxyl function are unsubstituted.

[0117] In yet another embodiment, the phenol is a mixture of aromatic polyphenol A2 and aromatic monophenol A2' as described above.

[0118] According to the present invention, in one embodiment, the aromatic polyphenol A2 can be a simple aromatic polyphenol molecule comprising one or more aromatic rings, at least one of these aromatic rings, in fact even each aromatic ring, carries at least two hydroxyl functions located in the meta position relative to each other, and the two ortho positions of at least one hydroxyl function are unsubstituted.

[0119] Similarly, in one embodiment, the aromatic monophenol A2' can be a simple aromatic monophenol molecule comprising one or more six-membered aromatic rings, at least one of these six-membered aromatic rings, or even each of the six-membered aromatic rings, carries a single hydroxyl functional group, the two ortho positions of the hydroxyl functional group are unsubstituted, or at least one ortho position of the hydroxyl functional group and the para position of the hydroxyl functional group are unsubstituted.

[0120] Such simple molecules contain no repeating units.

[0121] According to the present invention, in another embodiment, the aromatic polyphenol A2 may be a precondensation resin based on:

[0122] - at least one aromatic polyphenol comprising at least one aromatic ring carrying at least two hydroxyl functions located in the meta position relative to one another, at least one hydroxyl function being unsubstituted in both ortho positions; and

[0123] at least one compound comprising at least one aldehyde function and / or at least one compound comprising at least two hydroxymethyl functions carried by an aromatic ring.

[0124] Such precondensate resins based on aromatic polyphenols are in accordance with the invention and, unlike the simple molecules described above, comprise repeating units which, where appropriate, comprise at least one aromatic ring carrying at least two hydroxyl functions located in meta position relative to one another.

[0125] Similarly and according to the invention, in another embodiment, the aromatic monophenol A2' may be a precondensation resin based on:

[0126] - at least one aromatic monophenol comprising at least one six-membered aromatic ring carrying a single hydroxyl function:

[0127] - the two ortho positions of the hydroxyl function are unsubstituted, or

[0128] - at least one position ortho to the hydroxyl function and one position para to the hydroxyl function are unsubstituted;

[0129] at least one compound comprising at least one aldehyde function and / or at least one compound comprising at least two hydroxymethyl functions carried by an aromatic ring.

[0130] Such precondensed resins based on aromatic monophenols are in accordance with the invention and, unlike the simple molecules described above, comprise repeating units which, where appropriate, comprise at least one six-membered aromatic ring carrying a single hydroxyl function.

[0131] In another embodiment, phenol A21 is a mixture of an aromatic polyphenol and an aromatic polyphenol-based precondensed resin forming a single molecule.

[0132] In yet another embodiment, phenol A21 is a mixture of an aromatic monophenol and a precondensed resin based on an aromatic monophenol to form a single molecule.

[0133] In the specific embodiments below, the aromatic rings of the aromatic polyphenols and / or aromatic monophenols are described. For the sake of clarity, the "aromatic polyphenols" and / or "aromatic monophenols" are described herein in their simple molecular form. The aromatic polyphenols and / or the aromatic monophenols can then be condensed and partially define the repeating units. The characteristics of the precondensed resin are described in more detail later.

[0134] Aromatic polyphenol A2

[0135] In a preferred embodiment, the aromatic ring of the aromatic polyphenol carries three hydroxyl functional groups located in the meta position relative to each other.

[0136] Preferably, the two ortho positions of each hydroxyl function are unsubstituted. This is understood to mean that the two carbon atoms located on either side (in ortho position) of the hydroxylated carbon atom (ie the carbon atom carrying the hydroxyl function) carry a single hydrogen atom.

[0137] Still more preferably, the remainder of the aromatic ring of the aromatic polyphenol is unsubstituted. This is understood to mean that the other carbon atoms of the remainder of the aromatic ring (other than the carbon atom carrying the hydroxyl function) carry a single hydrogen atom.

[0138] In one embodiment, the aromatic polyphenol comprises a plurality of aromatic rings, at least two of which each bear at least two hydroxyl functional groups located in the meta position relative to each other, both ortho positions of at least one hydroxyl functional group in at least one aromatic ring being unsubstituted.

[0139] In a preferred embodiment, at least one aromatic ring of the aromatic polyphenol carries three hydroxyl functions which are located in meta position relative to one another.

[0140] Preferably, both ortho positions of each hydroxyl function of at least one aromatic ring are unsubstituted.

[0141] Still more preferably, both ortho positions of each hydroxyl function of each aromatic ring are unsubstituted.

[0142] Advantageously, the or each aromatic ring of the aromatic polyphenol is a benzene ring.

[0143] As examples of aromatic polyphenols comprising only one aromatic ring, mention may in particular be made of resorcinol and phloroglucinol, which, as indications, have the structural formulae (IV) and (V), respectively:

[0144]

[0145] For example, in the case where the aromatic polyphenol comprises a plurality of aromatic rings, at least two of these aromatic rings are the same or different and are selected from aromatic rings having the following general formula:

[0146]

[0147] Wherein, if there are multiple symbols Z1 and Z2 on the same aromatic ring, the symbols Z1 and Z2 are identical or different and represent atoms (such as carbon, sulfur or oxygen) or connecting groups, which are at least divalent by definition and connect at least these two aromatic rings to the rest of the aromatic polyphenol.

[0148] Another example of an aromatic polyphenol is 2,2',4,4'-tetrahydroxydiphenyl sulfide having the following structural formula (VII):

[0149]

[0150] Another example of an aromatic polyphenol is 2,2',4,4'-tetrahydroxybenzophenone having the following structural formula (VIII):

[0151]

[0152] It is noted that each of compounds VII and VIII is an aromatic polyphenol comprising two aromatic rings (having the formula VI-c), wherein each aromatic ring carries at least two (in this case two) hydroxyl functions located in the meta position relative to each other.

[0153] It is noted that in the case of aromatic polyphenols containing at least one aromatic ring according to formula VI-b, the two ortho positions of each hydroxyl function of at least one aromatic ring are unsubstituted. In the case of aromatic polyphenols containing a plurality of aromatic rings according to formula VI-b, the two ortho positions of each hydroxyl function of each aromatic ring are unsubstituted.

[0154] According to one embodiment of the present invention, the aromatic polyphenol is selected from resorcinol, phloroglucinol, 2,2',4,4'-tetrahydroxydiphenyl sulfide, 2,2',4,4'-tetrahydroxybenzophenone and mixtures of these compounds.

[0155] In a particularly advantageous embodiment, the aromatic polyphenol is phloroglucinol.

[0156] In one embodiment, the aromatic polyphenol A2 comprises a precondensed resin based on an aromatic polyphenol as described in any of these embodiments.

[0157] The precondensation resin is advantageously based on:

[0158] at least one aromatic polyphenol as defined above, preferably chosen from resorcinol, phloroglucinol, 2,2',4,4'-tetrahydroxydiphenyl sulfide, 2,2',4,4'-tetrahydroxybenzophenone and mixtures thereof; and

[0159] at least one compound capable of reacting with aromatic polyphenols and comprising at least one aldehyde function and / or at least one compound capable of reacting with aromatic polyphenols and comprising at least two hydroxymethyl functions, preferably an aromatic aldehyde comprising at least one aromatic ring carrying at least one aldehyde function.

[0160] The compound capable of reacting with the aromatic polyphenols and with the compound A1 may be an aromatic compound as defined above or any other aldehyde. Advantageously, the compound is chosen from: aromatic compounds comprising an aromatic ring with at least two functional groups (one of these functional groups is a hydroxymethyl function and the other functional group is an aldehyde function or a hydroxymethyl function), formaldehyde, furfural, 2,5-furandicarboxaldehyde, 1,4-phthalaldehyde, 1,3-phthalaldehyde, 1,2-phthalaldehyde and mixtures of these compounds. Very advantageously, when the compound capable of reacting with the aromatic polyphenols is an aromatic compound comprising an aromatic ring with at least two functional groups (one of these functional groups is a hydroxymethyl function and the other functional group is an aldehyde function or a hydroxymethyl function), the compound is chosen from 5-(hydroxymethyl)furfural, 2,5-di(hydroxymethyl)furan and mixtures of these compounds.

[0161] Thus, in the precondensation resin based on aromatic polyphenols, the recurring units correspond to the characteristics of the aromatic polyphenols as defined above, with the difference that at least one unsubstituted carbon atom of the aromatic ring is linked to another unit.

[0162] Whatever the compounds other than the aromatic polyphenols which are the basis of the precondensation resin, the precondensation resin does not contain free formaldehyde. This is because, even in the case where the precondensation resin is based on aromatic polyphenols and formaldehyde as described above, since formaldehyde has reacted with the aromatic polyphenols, the precondensation resin does not contain free formaldehyde which is easily able to react with the compound A1 according to the invention in a subsequent step.

[0163] Aromatic polyphenol A2 may also include a mixture of free aromatic polyphenol molecules as described above and a precondensation resin based on aromatic polyphenols. In particular, aromatic polyphenol A2 may also include a mixture of phloroglucinol and a precondensation resin based on phloroglucinol.

[0164] Aromatic monophenol A2'

[0165] Aromatic monophenol A2' can conform to two variants. In one variant, the two ortho positions of the hydroxyl function are unsubstituted. In another variant, at least one ortho position of the hydroxyl function and the para position of the hydroxyl function are unsubstituted.

[0166] Advantageously, in the variant in which at least one ortho position to the hydroxy function and the para position to the hydroxy function are unsubstituted, a single ortho position is unsubstituted and the para position to the hydroxy function is unsubstituted.

[0167] Preferably, regardless of the variant, both ortho positions of the hydroxyl function are unsubstituted. This is understood to mean that the two carbon atoms located on either side (in ortho position) of the hydroxylated carbon atom (ie the carbon atom carrying the hydroxyl function) carry a single hydrogen atom.

[0168] Still more preferably, the remainder of the aromatic ring is unsubstituted. This is understood to mean that the other carbon atoms of the remainder of the aromatic ring (other than the carbon atom carrying the hydroxyl function) carry a single hydrogen atom.

[0169] In one embodiment, the aromatic monophenol comprises a plurality of six-membered aromatic rings, at least two of the six-membered aromatic rings each carrying a single hydroxyl functional group, and for at least one hydroxyl functional group, both ortho positions to the hydroxyl functional group are unsubstituted, or at least one ortho position to the hydroxyl functional group and the para position to the hydroxyl functional group are unsubstituted.

[0170] Preferably, both ortho positions of each hydroxyl function of the at least one six-membered aromatic ring are unsubstituted.

[0171] Still more preferably, both ortho positions of each hydroxyl function of each six-membered aromatic ring are unsubstituted.

[0172] Still more preferably, the remainder of each aromatic ring is unsubstituted. This is understood to mean that the other carbon atoms of the remainder of each aromatic ring (except the carbon atoms carrying the hydroxyl function or carrying the groups linking the aromatic rings together) carry a single hydrogen atom.

[0173] Advantageously, the or each aromatic ring of the aromatic monophenol is a benzene ring.

[0174] Preferably, the aromatic monophenol is selected from phenol, o-cresol, m-cresol, p-cresol, o-chlorophenol, m-chlorophenol, p-chlorophenol, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 4-vinylphenol, 4-ethylphenol, 4-isopropylphenol, 4-isobutylphenol, p-coumaric acid and mixtures of these compounds.

[0175] In one embodiment, the aromatic monophenol A2' comprises a precondensed resin based on an aromatic monophenol as described in any of these embodiments.

[0176] The precondensation resin is advantageously based on:

[0177] at least one aromatic monophenol as defined above, preferably chosen from phenol, o-cresol, m-cresol, p-cresol, o-chlorophenol, m-chlorophenol, p-chlorophenol, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 4-vinylphenol, 4-ethylphenol, 4-isopropylphenol, 4-isobutylphenol, p-coumaric acid and mixtures of these compounds; and

[0178] at least one compound capable of reacting with an aromatic monophenol and comprising at least one aldehyde function and / or at least one compound capable of reacting with an aromatic monophenol and comprising at least two methylol functions, preferably an aromatic aldehyde comprising at least one aromatic ring carrying at least one aldehyde function.

[0179] The compound capable of reacting with the aromatic monophenol may be compound A1 as defined above or any other aldehyde. Advantageously, the compound capable of reacting with the aromatic polyphenol is chosen from: aromatic compounds comprising an aromatic ring with at least two functional groups (one of these functional groups is a hydroxymethyl function and the other functional group is an aldehyde function or a hydroxymethyl function), formaldehyde, furfural, 2,5-furandicarboxaldehyde, 1,4-phthalaldehyde, 1,3-phthalaldehyde, 1,2-phthalaldehyde and mixtures of these compounds. Very advantageously, when the compound is an aromatic compound comprising an aromatic ring with at least two functional groups (one of these functional groups is a hydroxymethyl function and the other functional group is an aldehyde function or a hydroxymethyl function), the compound is chosen from 5-(hydroxymethyl)furfural, 2,5-di(hydroxymethyl)furan and mixtures of these compounds.

[0180] Thus, in the precondensation resin based on aromatic monophenols, the recurring units correspond to the characteristics of the aromatic monophenols as defined above, with the difference that at least one unsubstituted carbon atom of the six-membered aromatic ring is linked to another unit.

[0181] Whatever the compounds other than the aromatic monophenol which is the basis of the precondensation resin, the precondensation resin does not contain free formaldehyde. This is because, even in the case where the precondensation resin is based on an aromatic monophenol and formaldehyde as described above, since the formaldehyde has reacted with the aromatic monophenol, the precondensation resin does not contain free formaldehyde which is easily capable of reacting with the compound A1 according to the invention in a subsequent step.

[0182] Aromatic monophenol A2' may also include a mixture of free aromatic monophenol molecules as described above and a precondensation resin based on aromatic monophenol. In particular, aromatic monophenol A2' may also include a mixture of phenol and a precondensation resin based on phenol.

[0183] Mixture of aromatic polyphenol A2 and aromatic monophenol A2'

[0184] Phenol A21 may also include a mixture of the aromatic polyphenol A2 and the aromatic monophenol A2' as described above.

[0185] Preferably, phenol A21 comprises a mixture of an aromatic polyphenol and a precondensed resin based on an aromatic polyphenol.

[0186] Elastomer latex

[0187] The adhesive composition also comprises an elastomer latex, preferably an unsaturated elastomer latex. When the adhesive composition is used to coat an element intended to be embedded in an elastomer matrix, this elastomer latex can provide an elastomer physical interface. When the elastomer latex is undersaturated, it also provides a chemical interface by being able to form a bridging unsaturation with the crosslinking system of the elastomer matrix.

[0188] It is to be recalled that latex is a stable dispersion of elastomeric particles suspended in a generally aqueous solution. Thus, an elastomer latex is a liquid composition comprising a liquid solvent (generally water) and at least one elastomer or rubber dispersed in the liquid solvent to form a suspension. Thus, latex is not a rubber composition comprising an elastomeric matrix or a rubber matrix dispersed with at least one other component. A rubber composition is in a plastic state in an uncured (non-crosslinked) state and in an elastic state in a cured (crosslinked) state, but never in a liquid state, unlike latex.

[0189] Unsaturated (ie with carbon-carbon double bonds) elastomer latexes, in particular diene elastomer latexes, are well known to those skilled in the art. They constitute in particular the elastomeric matrix of the RFL adhesives described in the background of the present description.

[0190] The unsaturated elastomer of the latex is preferably a diene elastomer, more preferably a diene elastomer chosen from butadiene copolymers, styrene-butadiene copolymers, vinylpyridine-styrene-butadiene terpolymers, natural rubbers other than chlorinated natural rubbers and mixtures of these elastomers.

[0191] Advantageously, the step of depositing the aqueous binder composition is followed by a step of drying the GRP plastic at a temperature greater than or equal to 120° C. for at least 5 seconds, followed by a heat treatment at a temperature greater than or equal to 180° C. for at least 5 seconds.

[0192] The composite material according to the invention

[0193] The invention also relates to an elastomeric composite reinforced with at least one or more sized glass reinforced plastic (GRP) strands as defined above.The elastomeric matrix is ​​based on an elastomeric composition comprising at least one elastomer and another component.

[0194] Preferably, the elastomeric composition comprises a diene elastomer. An elastomer or rubber of the "diene" type (the two terms are synonymous) is generally understood to mean an elastomer obtained at least partially (ie homopolymer or copolymer) from diene monomers (monomers carrying two conjugated or non-conjugated carbon-carbon double bonds).

[0195] The elastomeric composition may comprise just one diene elastomer or a mixture of several diene elastomers, the diene elastomers possibly being combined with any type of synthetic elastomer other than diene elastomers, indeed even with polymers other than elastomers, such as thermoplastic polymers.

[0196] In a first embodiment, preferably intended for tire use, the elastomeric composition comprises a diene elastomer chosen from polybutadiene (BR), natural rubber (NR), synthetic polyisoprene (IR), various butadiene copolymers, various isoprene copolymers and mixtures of these elastomers.

[0197] These copolymers are more preferably chosen from butadiene / styrene copolymers (SBR), whether prepared by emulsion polymerization (ESBR) or by solution polymerization (SSBR), isoprene / butadiene copolymers (BIR), isoprene / styrene copolymers (SIR) and isoprene / butadiene / styrene copolymers (SBIR).

[0198] In a second embodiment, preferably intended for conveyor belts, the elastomeric composition comprises an elastomer selected from alpha-olefin ethylene elastomers, polychloroprene elastomers and mixtures of these elastomers, one or more other elastomers. The elastomeric composition may also comprise one or more other ingredients.

[0199] Advantageously, the elastomer of the ethylene / α-olefin type is chosen from ethylene / propylene copolymers (EPM), ethylene / propylene / diene copolymers (EPDM) and mixtures of these copolymers.

[0200] Preferably, the elastomeric composition comprises a reinforcing filler.

[0201] When reinforcing fillers are used, any type of reinforcing filler known to be capable of reinforcing elastomeric compositions useful for the manufacture of tires may be used, such as organic fillers, such as carbon black, reinforcing inorganic fillers, such as silica, or blends of these two types of fillers, in particular blends of carbon black and silica.

[0202] Any carbon black conventionally used in tires ("tire-grade" carbon black) is suitable as carbon black. Mention shall more particularly be made of reinforcing carbon blacks of the 100, 200 or 300 series (ASTM grades), for example.

[0203] In the case of using carbon black and isoprene elastomer, the carbon black may, for example, have been incorporated into the isoprene elastomer in the form of a masterbatch (see, for example, applications WO 97 / 36724 and WO 99 / 16600).

[0204] As examples of organic fillers other than carbon black, mention may be made of functionalized polyvinyl aromatic organic fillers as described in applications WO-A-2006 / 069792 and WO-A-2006 / 069793.

[0205] In the present application, the term "reinforcing inorganic filler" is understood, by definition, to mean any inorganic or mineral filler, whatever its colour and its origin (natural or synthetic), also known as "white filler", "transparent filler" or indeed even "non-black filler" relative to carbon black, capable of reinforcing the elastomeric composition alone, without the need for means other than intermediate coupling agents, in other words capable of replacing conventional tire-grade carbon black in its reinforcing effect. In a known manner, such fillers are generally characterized by the presence of hydroxyl (-OH) groups on their surface.

[0206] It is not important in which physical state the reinforcing inorganic filler is provided, whether it is in the form of a powder, microspheres, granules, beads or any other suitable densified form. Of course, "reinforcing inorganic filler" is also understood to mean a mixture of different reinforcing inorganic fillers, in particular a mixture of highly dispersible siliceous fillers and / or aluminous fillers as described below.

[0207] Mineral fillers of the siliceous type, in particular silicon dioxide (SiO2), or of the aluminous type, in particular aluminum oxide (Al2O3), are particularly suitable as reinforcing inorganic fillers. The silicon dioxide used may be any reinforcing silicon dioxide known to those skilled in the art, in particular one having a BET specific surface area and a CTAB specific surface area of ​​less than 450 m 2 / g, preferably 30m 2 / g to 400m 2 As highly dispersible precipitated silicas (HDS), mention may be made of, for example, Ultrasil 7000 and Ultrasil 7005 silicas from Evonik, Zeosil 1165MP, 1135MP and 1115MP silicas from Rhodia, Hi-Sil EZ150G silica from PPG, Zeopol 8715, 8745 and 8755 silicas from Huber or silicas with a high specific surface area as described in application WO 03 / 16837.

[0208] Finally, those skilled in the art will understand that reinforcing fillers of another nature, in particular organic in nature, may be used as fillers equivalent to the reinforcing inorganic fillers described in this section, provided that the reinforcing filler is covered with an inorganic layer such as silica, or contains functional sites on its surface, in particular hydroxyl sites, that require the use of a coupling agent to form a bond between the filler and the elastomer.

[0209] Preferably, the content of total reinforcing fillers (carbon black and / or reinforcing inorganic fillers, such as silica) ranges from 5 to 120 phr, more preferably from 5 to 100 phr, still more preferably from 5 to 90 phr.

[0210] Carbon black can advantageously constitute the sole reinforcing filler or the main reinforcing filler. Of course, only one carbon black or a blend of multiple carbon blacks with different ASTM grades can be used. Carbon black can also be blended with other reinforcing fillers, in particular reinforcing inorganic fillers as described above (in particular silica).

[0211] When an inorganic filler (such as silica) is used alone or in a blend with carbon black in the rubber composition, its content is in the range of 0 phr to 70 phr, preferably 0 phr to 50 phr, and particularly 5 phr to 70 phr, and more preferably the ratio varies from 5 phr to 50 phr, particularly 5 phr to 40 phr.

[0212] Preferably, the elastomeric composition comprises various additives.

[0213] The rubber composition may also contain all or part of the customary additives conventionally used in elastomeric compositions intended for the manufacture of tyres, such as, for example, plasticizers or extender oils, whether of aromatic or non-aromatic nature, pigments, protective agents (for example antiozonant waxes, chemical antiozonants or antioxidants), antifatigue agents or adhesion promoters.

[0214] Preferably, the elastomeric composition comprises a crosslinking system, more preferably a vulcanizing system.

[0215] In a first embodiment, preferably intended for use in tires, the elastomeric composition comprises a vulcanization system.

[0216] The vulcanization system comprises a vulcanizing agent, such as sulfur.

[0217] Preferably, the vulcanization system comprises a vulcanization activator, such as zinc oxide and stearic acid.

[0218] Preferably, the vulcanization system comprises a vulcanization accelerator and / or a vulcanization retardant.

[0219] Advantageously, the composite material satisfies that the elastomeric matrix is ​​based on an elastomeric composition comprising a crosslinking system comprising a molecular sulphur content ranging from 1 phr to 5 phr. Molecular sulphur is understood to mean the sulphur consisting of S n (where n>2) compounds. Specifically, the inventors have proposed the hypothesis that there is competition between the adhesion of the adhesive composition and the adhesion of the copper zinc sulfide dendrites. Now, this competition tends to reduce the overall level of adhesion. The more the content of sulfur present in the elastomeric matrix is ​​reduced, the more this competition is reduced, and the more the adhesion level of the sole adhesive composition is improved.

[0220] Very advantageously, the molecular sulfur content of the crosslinking system of the elastomeric composition is less than or equal to 4 phr, preferably less than or equal to 3 phr, more preferably less than or equal to 2.5 phr. In addition to further reducing the competition between the adhesion of the adhesive composition and the adhesion of the copper-zinc sulfide dendrites, it also increases the shelf life of the elastomeric composition at room temperature, avoiding the risk of pre-vulcanization that would occur if higher sulfur contents were used.

[0221] Very advantageously, the molecular sulphur content of the crosslinking system of the elastomeric composition is greater than or equal to 1.5 phr, preferably greater than or equal to 2 phr.

[0222] Sulfur content was measured by elemental analysis using a Thermo Scientific Flash 2000 microanalyzer. The analysis included a combustion step of the sample followed by a separation step of the compounds formed. About 1 mg of sample was introduced into the microanalyzer and subjected to a flash combustion of 1000°C under oxygen. The resulting gas was then oxidized by excess oxygen and a tungstic anhydride catalyst. The subsequent reduction step through copper allowed the capture of excess oxygen and the reduction of nitrogen oxides to N2, and the reduction of sulfites to sulfur dioxide SO2. Water was captured and the resulting compounds N2, CO2 and SO2 were subsequently separated on a chromatographic column and then detected with a thermal conductivity meter. Total sulfur was quantified by measuring the area of ​​the SO2 peak after calibration with a standard.

[0223] The combined vulcanization accelerator, vulcanization retarder and vulcanization activator are used at a preferred content ranging from 0.5 to 15 phr. The vulcanization activator is used at a preferred content ranging from 0.5 to 12 phr.

[0224] Suitable crosslinking systems are preferably based on sulfur and primary vulcanization accelerators, in particular sulfenamide-type accelerators. In addition to this vulcanization system, there are also various known secondary vulcanization accelerators or vulcanization activators, such as zinc oxide, stearic acid, guanidine derivatives (in particular diphenylguanidine), etc.

[0225] As (primary or secondary) accelerator, any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur may be used, in particular thiazole-type accelerators and derivatives thereof, thiuram-type accelerators and zinc dithiocarbamate-type accelerators. These accelerators are more preferably chosen from 2-mercaptobenzothiazolyl disulfide (abbreviated as "MBTS"), N-cyclohexyl-2-benzothiazolesulfenamide (abbreviated as "CBS"), N,N-dicyclohexyl-2-benzothiazolesulfenamide (abbreviated as "DCBS"), N-(tert-butyl)-2-benzothiazolesulfenamide (abbreviated as "TBBS"), N-(tert-butyl)-2-benzothiazolesulfenimide (abbreviated as "TBSI"), zinc dibenzyldithiocarbamate (abbreviated as "ZBEC") and mixtures of these compounds. Preferably, a sulfenamide-type primary accelerator is used.

[0226] In a second embodiment, preferably intended for conveyor belts, the crosslinking system is substantially free of sulfur and advantageously comprises a peroxide, preferably an organic peroxide. Advantageously, the peroxide content ranges from 0.5 to 8 phr. Advantageously, the crosslinking system comprises a co-crosslinking agent, preferably sulfur or triallyl cyanurate. Advantageously, the content of the co-crosslinking agent is from 0.5 to 5 phr.

[0227] Tire according to the invention

[0228] The invention also relates to a tyre.The elastomeric composite material of the invention can advantageously be used to reinforce tyres for all types of vehicles, in particular passenger vehicles or industrial vehicles, such as heavy vehicles.

[0229] Conveyor belt according to the invention

[0230] The present invention also relates to a conveyor belt. For example, this conveyor belt can be a power transmission belt. BRIEF DESCRIPTION OF THE DRAWINGS

[0231] The invention will be better understood on reading the following description given by way of non-limiting example only and with reference to the accompanying drawings, in which:

[0232] - Figure 1 is a schematic diagram of a tire according to the present invention; and

[0233] - Figure 2 is a schematic representation of a method for gluing one or more GRP strands comprising the steps of the method according to the invention. DETAILED DESCRIPTION

[0234] Attached Figure 1 Very schematically (not to a particular scale) there is represented a radial section through a tyre for passenger vehicles according to the invention.

[0235] This tire 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 by a bead wire 5. The crown 2 is covered by a tread (not shown in this schematic diagram). 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 arranged, for example, towards the outside of the tire 1, which is here represented to be fitted on its rim 9. The carcass reinforcement 7 is formed in a manner known per se by at least one ply reinforced by "radial" cords (for example textile cords), i.e. these cords are arranged almost parallel to each other and extend from one bead to the other, so as to form an angle of between 80° and 90° with the circumferential median plane (a plane perpendicular to the axis of rotation of the tire, situated halfway between the two beads 4 and passing through the center of the crown reinforcement 6).

[0236] This tire 1 of the invention has, for example, the essential feature that at least one crown reinforcement 6 and / or carcass reinforcement 7 comprises an elastomeric composite material according to the invention. The tire has the preferred feature that at least its belt layer and / or its carcass reinforcement comprises a multilayer laminate according to the invention, consisting of at least one multiple composite reinforcement according to the invention, arranged between and in contact with two layers of diene rubber composition. According to a particular embodiment of the invention, this composite material of the invention can be used in the form of parallel sections located below the tread, as described in patent EP 1167080. According to another possible exemplary embodiment of the invention, the bead area can be reinforced by this composite material; for example, the bead wire can be formed wholly or partly by a composite material according to the invention.

[0237] For example, a conveyor belt according to the invention has the essential feature that it comprises an elastomeric composite material according to the invention.

[0238] Needless to say, the present invention relates to the object described above, namely an elastomeric composite and a tire or a conveyor belt comprising said elastomeric composite, both in the uncured state (before crosslinking) and in the cured state (after crosslinking).

[0239] Figure 2 An embodiment of an apparatus, indicated by reference numeral 30, for gluing one or more GRP strands according to the present invention is described.

[0240] The production device 30 is capable of producing one or more sized GRP strands.

[0241] In the running direction of the GRP strands through the device 30, the device 30 comprises, from upstream to downstream: a device 34 for upstream storage of the GRP strands; a first aqueous pre-bonding bath 36, which contains a composition based on an epoxy compound and a blocked diisocyanate compound, in which the GRP strands are immersed; a device 40 for drying the pre-bonded strands by heat treatment; a second bath 42 consisting of an aqueous adhesive composition for depositing this adhesive composition on the GRP strands; a device 44 for heat treatment of the glued GRP strands and a device 46 for downstream storage of the heat-treated glued GRP.

[0242] The upstream storage device 34 and the downstream storage device 46 each comprise a reel for storing the GRP strands, which are capable of unwinding and winding the GRP strands, respectively.

[0243] An example of a method for sizing one or more glass reinforced plastic (GRP) strands will now be described.

[0244] During the process, a pre-bonding step is carried out in an aqueous solution of a first bath based on epoxy resin and blocked diisocyanate (e.g. based on polyglycerol polyglycidyl ether and N,N'-(methylenedi-p-phenylene)bis[hexahydro-2-oxo-1H-azepin-1-carboxamide 4,4'-diisocyanate]. The ingredients are introduced into water by stirring, for example, in the following order: 1.5% by weight of polyglycerol polyglycidyl ether (e.g. Denacol EX-512 from Nagase Chemicals), 0.02% of zinc acetate, 0.08% of defoamer, 15.15% of a 20% solution of N,N'-(methylenedi-p-phenylene)bis[hexahydro-2-oxo-1H-azepin-1-carboxamide 4,4'-diisocyanate] and 83.6% by weight of water.

[0245] To this end, a plurality of glass reinforced plastic (GRP) strands are brought into contact with a first bath.

[0246] Next, the glass reinforced plastic (GRP) strands are dried, for example by passing through a high frequency heating tunnel or oven (for example at 170°C for 20 seconds), and then heat treated (for example at 220°C for 30 seconds).

[0247] Next, a step of depositing an aqueous adhesive composition is performed, the aqueous adhesive composition comprising a mixture of water, an unsaturated elastomer latex and a resin based on phloroglucinol and 1,4-phthalaldehyde. The proportions of these various components are described below.

[0248] To this end, a plurality of glass reinforced plastic (GRP) strands are brought into contact with the adhesive composition. To this end, the glass reinforced plastic (GRP) strands are continuously unwound from storage reels in the storage device 34 and passed through a first bath, then through a heat treatment device, then through a second bath comprising an aqueous adhesive composition, and through a heat treatment device, for example, by passing through a heating tunnel or oven (e.g. at 170° C. for 20 seconds) and then subjected to heat treatment (e.g. at 220° C. for 30 seconds).

[0249] Comparison test

[0250] Adhesion test

[0251] Various control sized glass reinforced plastic (GRP) strands T, T1, T1', T2 and T2' and sized glass reinforced plastic (GRP) strands C1 and C2 according to the invention were tested by a test aimed at measuring the pull-out force of these sized glass reinforced plastic (GRP) strands embedded in an elastomeric matrix.

[0252] The glass reinforced plastic (GRP) strands were coated with each of the solutions described in Table 1 below and then dried in a drying oven at 170° C. for 20 seconds. The adhesive composition was then crosslinked by passing the glass reinforced plastic (GRP) strands through a treatment furnace at 220° C. for 30 seconds. The combination was then integrated by curing with a natural rubber composition through a vulcanization heat treatment to form a composite material specimen described below.

[0253] The quality of the bond between the rubber composition and the glass reinforced plastic (GRP) strands was then determined by a test in which the force required to extract a section of the glass reinforced plastic (GRP) strand from the vulcanized rubber composition was measured. The rubber composition was a conventional composition that can be used for calendering tire carcass reinforcement plies, these plies comprising glass reinforced plastic (GRP) strands embedded in an elastomeric matrix based on natural rubber, carbon black and standard additives.

[0254] More specifically, the vulcanized rubber is a block of elastomeric composition consisting of two sheets of dimensions 200 mm×4.5 mm and 3.5 mm thick, applied next to each other before curing (the thickness of the resulting block is then 7 mm). It is during the preparation of this block that the glass reinforced plastic (GRP) strands (15 sections in total) are embedded between the two rubber sheets of elastomeric composition in the uncured state, at equal distances and while allowing the cord ends to protrude sufficiently on either side of these sheets to carry out the subsequent tensile test. The block comprising the glass reinforced plastic (GRP) strands is then placed in a suitable mould and then cured under pressure. The curing temperature and the curing time are adapted to the test conditions targeted and are at the discretion of the person skilled in the art; by way of example, in the present case, the block is cured at 160° C. for 15 min.

[0255] At the end of curing, the test specimen thus consisting of the vulcanized block and sections of 15 glass reinforced plastic (GRP) strands is placed between the jaws of a suitable tensile testing machine, making it possible to test each section individually at a given speed and a given temperature (for example, in the present case, at 100 mm / min and 20°C).

[0256] The adhesion level is characterized by measuring the "pull-off" force (denoted by Fmax0) to pull the glass reinforced plastic (GRP) strands from the test specimen. For the pull-off force (Fmax0), the adhesion value of the control T is set to 100, which represents the conventional method for gluing glass reinforced plastics described in application WO2016116457.

[0257] The results of adhesion tests carried out on sized glass reinforced plastic (GRP) strands are summarized in Table 1 below.

[0258] Moisture sensitivity test

[0259] Each GRP strand was coated with the adhesive composition to be tested according to the method described in Table 1 below (with or without a first bath). Each sized GRP strand was dried in a drying oven at 170° C. for 20 seconds. The adhesive composition was then crosslinked by passing the sized GRP strand through a treatment oven at 220° C. for 30 seconds.

[0260] The resistance of the interface to humid conditions is characterized by measuring the breaking strength of the glued glass reinforced plastic (GRP) strands (denoted by Fmax0) and the breaking strength of the glued glass reinforced plastic (GRP) strands after heat treatment in an oven at 90°C and 90% humidity level for 70 hours (denoted by Fmax70). The breaking strength Fmax0 is arbitrarily set to 100. The value of the breaking strength Fmax70 of each glued glass reinforced plastic (GRP) strand is necessarily less than 100, and the more it is less than 100, the more sensitive the glued glass reinforced plastic (GRP) strand is to humid conditions.

[0261] The reduction D expressed as a percentage corresponding to the loss of breaking strength between Fmax0 and Fmax70 is calculated. D satisfies D=(1-Fmax70 / Fmax0) x 100. The smaller the reduction value D, the less sensitive the sized glass reinforced plastic (GRP) strand is to humid conditions.

[0262] The results of the moisture sensitivity tests carried out on sized glass reinforced plastic (GRP) strands are summarised in Table 1 below.

[0263] For both the first and second baths, the values ​​for the various compounds are given in weight % solids relative to a formulation base of 100.

[0264] [Table 1]

[0265]

[0266]

[0267] (1) Polyglycerol polyglycidyl ether ([EX512 supplied by Nagase])

[0268] (2) DiNCO 4,4'-diphenylmethylene diisocyanate ([Grilbond IL-6 50% supplied by EMS])

[0269] (3) 1,4-Benzenedicarboxaldehyde (from ABCR; purity 98%)

[0270] (4) Formaldehyde (from Caldic; diluted to 36%)

[0271] (5) Phloroglucinol (from Alfa Aesar; purity 99%)

[0272] (6) Resorcinol (Sumitomo CHIBA)

[0273] It was observed that the adhesion level remained high regardless of whether a first bath was used or not, even in the case where no first bath was used (T1').

[0274] It is observed that the composites C1 and C2 according to the invention have a breaking strength Fmax0 which is admittedly lower than that of the controls T, T1, T1' and T2'' using blocked diisocyanates in the second bath, but which is nevertheless sufficient to ensure satisfactory adhesion compatible with use in tires or conveyor belts.

[0275] It is also observed that the presence of blocked diisocyanates in the first bath limits the reduction, whether or not a second bath (T, T2", C1 and C2) is used, and that the presence of diisocyanates has an impact on the resistance to humid conditions if T1 is compared to C1 and T2 to C2.

[0276] Therefore, the presence of blocked diisocyanates will have an impact on moisture resistance.

[0277] A pre-bonding step is therefore essential, on the one hand to maintain a good level of adhesion initially, and on the other hand to guarantee the resistance of the bonding interface to humid conditions without using products that have a negative impact on the environment.

[0278] The method according to the invention thus makes it possible to satisfactorily bond the composite material C2 according to the invention to an elastomeric matrix without the need to use an adhesive composition in combination with a product that has a negative impact on the environment. In addition, the adhesion of this composite material is relatively high and is not easily reduced under humid conditions.

[0279] The present invention is not limited to the above-described embodiments.

Claims

1. A method for gluing one or more strands of glass reinforced plastic (GRP), characterized in that The method comprises the following steps: a) carrying out a step of pre-bonding one or more strands of GRP plastic by immersing said strand or strands in a first aqueous bath comprising a composition based on: - epoxy compounds; and - blocked diisocyanate compounds; b) carrying out a step of depositing on the GRP plastic strands by immersing the GRP plastic strands in a second bath comprising an aqueous binder composition based on: - at least one compound A1 comprising at least one aldehyde function; - at least one phenol A21; at least one unsaturated elastomeric latex comprising at least one elastomer chosen from butadiene copolymers, styrene-butadiene copolymers, vinylpyridine-styrene-butadiene terpolymers, natural rubbers other than chlorinated natural rubbers and mixtures of these elastomers; The content of the blocked diisocyanate compound in the aqueous adhesive composition of the second bath is strictly less than 0.50% by weight.

2. The method according to the preceding claim, wherein: The weight content of the blocked diisocyanate compound in the aqueous adhesive composition of the second bath is strictly less than 0.40%, preferably less than or equal to 0.30%, more preferably less than or equal to 0.20%, more preferably less than or equal to 0.10%, even more preferably less than or equal to 0.05%.

3. A method according to any one of the preceding claims, wherein: The epoxy compound is selected from diethylene glycol diglycidyl ether, polyethylene diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, sorbitol polyglycidyl ether or isosorbide diglycidyl ether; preferably polyglycerol polyglycidyl ether.

4. A method according to any one of the preceding claims, wherein: The blocked diisocyanate compound is selected from diphenylmethane diisocyanate and polyphenylene polymethylene polyisocyanate, and is preferably N,N′-(methylenedi-p-phenylene)bis[hexahydro-2-oxo-1H-azepine-1-carboxamide 4,4′-diisocyanate.

5. The method according to any one of claims 1 to 4, wherein: The compound A1 is formaldehyde.

6. The method according to any one of claims 1 to 4, wherein: The compound A1 comprises at least one aromatic ring which carries at least one aldehyde function.

7. The method according to the preceding claim, wherein: The compound A1 carries at least two aldehyde functions.

8. The method according to claim 6, wherein: The compound A1 is selected from 1,2-phthalaldehyde, 1,3-phthalaldehyde, 1,4-phthalaldehyde, 2-hydroxybenzene-1,3,5-tricarbaldehyde and a mixture of these compounds.

9. A composition according to any one of the preceding claims, wherein The phenol A21 is selected from: an aromatic polyphenol A2 comprising at least one aromatic ring carrying at least two hydroxyl functions located in the meta position relative to one another, the two ortho positions of at least one hydroxyl function being unsubstituted; - an aromatic monophenol A2' comprising at least one six-membered aromatic ring carrying a single hydroxyl function, wherein: - the two ortho positions of the hydroxyl function are unsubstituted; or - at least one position ortho to the hydroxyl function and one position para to the hydroxyl function are unsubstituted; - A mixture of A2 and A2'.

10. The method according to the preceding claim, wherein: The aromatic polyphenol A2 is selected from resorcinol, phloroglucinol, 2,2',4,4'-tetrahydroxydiphenyl sulfide, 2,2',4,4'-tetrahydroxybenzophenone and a mixture of these compounds, preferably phloroglucinol.

11. A method according to any one of the preceding claims, wherein: After step a) of pre-bonding the GRP plastic, a step of drying the GRP plastic is carried out by drying at a temperature greater than or equal to 120° C. for at least 5 seconds and then heat treating at a temperature greater than or equal to 180° C. for at least 5 seconds.

12. A method according to any one of the preceding claims, wherein: After step b) of depositing on the GRP plastic, a step of drying the GRP plastic is carried out by drying at a temperature greater than or equal to 120° C. for at least 5 seconds and then heat treating at a temperature greater than or equal to 180° C. for at least 5 seconds.

13. Elastomeric composite material reinforced by at least one or more sized glass reinforced plastic (GRP) strands embedded in an elastomeric matrix, characterized in that The sized glass reinforced plastic (GRP) strand is obtained by the method according to any one of claims 1 to 12.

14. A tire (1), characterized in that The tyre (1) comprises the elastomeric composite material according to claim 13.

15. A conveyor belt (P), characterized in that The conveyor belt (P) comprises the elastomeric composite material according to claim 13.

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