Improved bonding process for one or more strands of CVR Glass-Resin composite
A two-step bonding process for Glass-Resin CVR composites using epoxy and blocked diisocyanate pre-adhesion, followed by an aldehyde and phenol adhesive, addresses environmental concerns and enhances adhesion and humidity resistance, improving the durability of elastomer composites.
Patent Information
- Application Number
- FR2022004758
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2022-05-19
- Publication Date
- 2025-08-29
- Estimated Expiration
- 2042-05-19
AI Technical Summary
Existing methods for bonding Glass-Resin CVR composites to elastomer matrices require the use of adhesives that have a negative environmental impact and do not provide sufficient adhesion under humid conditions or after cooling.
A two-step bonding process involving pre-adhesion in an aqueous bath with epoxy and blocked diisocyanate followed by deposition in an adhesive composition containing an aldehyde compound and phenol, with reduced blocked diisocyanate content, to enhance adhesion and resistance to humidity.
The method achieves high initial adhesion and resistance to humid conditions without using blocked diisocyanate, extending the lifespan of composites and products like tires and belts.
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Abstract
Description
Title of the invention: Improved method for bonding one or more strands of CVR Glass-Resin composite
[0001] The field of the present invention is that of Glass-Resin composites, abbreviated to "CVR", and adhesive compositions or "glues" intended to make such elements adhere to elastomeric matrices such as those commonly used in elastomer articles or semi-finished products or in the field of tires or belts.
[0002] The present invention relates more particularly to an improved method for bonding one or more strands of Glass-Resin CVR composite, to the elastomer composite comprising this bonded CVR and to tires reinforced by such elastomer composites.
[0003] Known from the state of the art is a conventional method for bonding glass-resin composites as described in application WO2016116457 where it is conventionally known to carry out their pre-adhesion in a first bath generally based on epoxy and isocyanate in aqueous solution and then the glass-resin composites are bonded in a second bath with conventional aqueous adhesive compositions, for example adhesive compositions known under the name "RFL" (for resorcinol-formaldehyde-latex), as for example described in EP2006341, mixed with an aqueous solution based on blocked diisocyanate, then mixed in an elastomeric matrix with a 100% vinylpyridine latex phase. The blocked diisocyanate is added to the adhesive composition at a mass rate of 9% to improve adhesion.
[0004] Methods for bonding polyesters as described in application WO2021117519 are also known from the prior art, but the adhesion mechanism between an adhesive composition and the polyester is different from the adhesion mechanism between an adhesive composition and a glass-resin composite. In the adhesion mechanism between the polyester and an adhesive composition, covalent bonds are formed between the polyester and the adhesive system as well as secondary chemical bonds. Polyester is not very polar, so a pre-adhesion step is necessary to allow adhesion. In the adhesion mechanism between the glass-resin composite and an adhesive composition as described in application WO2008061544, the glass-resin composite has previously been crosslinked, the chemical functions on the surface are different from those implemented between the polyester and an adhesive composition and there is not necessarily a need for a pre-adhesion.
[0005] Thus, designers of elastomer articles, in particular tire manufacturers, are currently aiming to find new, simple processes for making Glass-Resin CVR composites adhere satisfactorily to elastomer matrices without requiring the use of an adhesive composition in association with products that have a negative impact on the environment. In addition, it is desirable that this adhesion is initially, that is to say after cooling following curing, relatively high and little degraded by humid conditions.
[0006] During its research, the Applicant discovered a process making it possible to meet the above objectives.
[0007] The subject of the invention is therefore a method for bonding one or more strands of Glass-Resin composite, abbreviated to "CVR", characterized in that it comprises the following steps: a) a step of pre-adhesion of one or more strands of CVR composite is carried out by soaking the strand(s) in a first aqueous bath comprising a composition based on: - an epoxy compound; and - a blocked diisocyanate compound; b) a deposition step is carried out on the CVR composite strand(s) by dipping the CVR composite strand(s) in a second bath comprising an aqueous adhesive composition based on: - at least one compound Al, the compound Al comprising at least one aldehyde function; - at least one phenol A21; - at least one unsaturated elastomer latex comprising at least one elastomer chosen from the group consisting of butadiene copolymers, styrene-butadiene copolymers, vinylpyridine-styrene-butadiene terpolymers, natural rubber with the exception of chlorinated natural rubber, and mixtures of these elastomers; the content of blocked diisocyanate compound in the aqueous adhesive composition of the second bath being at a mass rate strictly less than 0.50%.
[0008] The Applicant thus puts forward the hypothesis that the pre-adhesion step is an essential step for, on the one hand, maintaining a good level of initial adhesion and, on the other hand, guaranteeing resistance to humid conditions and / or to the temperature of the adhesive interface, without this requiring the use of blocked diisocyanate in the aqueous adhesive composition, the quantities of which it is desirable to reduce.
[0009] The invention also relates to an elastomer composite reinforced with at least one or more strands of glued CVR Glass-Resin composite embedded in a matrix of elastomer, in which the bonded Glass-Resin CVR composite strand(s) are obtained by the process as described above.
[0010] The composite according to the invention thus manufactured is advantageously usable, in particular for the reinforcement of tires, pneumatic or non-pneumatic, of all types of vehicles, in particular passenger vehicles or industrial vehicles such as heavy goods vehicles, civil engineering, aircraft, other transport or handling vehicles.
[0011] The invention also relates to a tire comprising the elastomer composite as described above.
[0012] The invention also relates to a belt comprising the elastomer composite as described above.
[0013] The method according to the invention allows a significant increase in the lifespan of the composites according to the invention, and therefore of the tires or belts comprising them, in particular in humid conditions demonstrating the resistance of the adhesive interface created.
[0014] Any interval of values designated by the expression "between a and b" represents the domain of values going from plus a to minus b (i.e., limits a and b excluded) while any interval of values designated by the expression "from a to b" means the domain of values going from a up to b (i.e., including the strict limits a and b).
[0015] In the context of the invention, the carbon products mentioned in the description may be of fossil or bio-sourced origin. In the latter case, they may be, partially or totally, derived from biomass or obtained from renewable raw materials derived from biomass.
[0016] In the present description, unless expressly indicated otherwise, all percentages (%) indicated are % by mass.
[0017] By elastomer composition is meant a composition comprising at least one elastomer (or indistinctly rubber) and at least one other constituent.
[0018] By "diene" elastomer (or indistinctly rubber) is meant an elastomer derived at least in part (i.e. a homopolymer or a copolymer) from diene monomer(s) (i.e., bearing(s) two carbon-carbon double bonds, conjugated or not). By "isoprene elastomer" is meant a homopolymer or a copolymer of isoprene, in other words a diene elastomer chosen from the group consisting of natural rubber (NR), synthetic polyisoprenes (IR), the various copolymers of isoprene and mixtures of these elastomers.
[0019] By elastomeric matrix is meant a matrix with elastomeric behavior.
[0020] By "meta position relative to each other" we mean that the functions hydroxyl are carried by carbons of the aromatic ring separated from each other by a single other carbon of the aromatic ring.
[0021] By "in the ortho position of a function" is meant the position occupied by the carbon of the aromatic ring immediately adjacent to the carbon of the aromatic ring carrying the function.
[0022] By "member" of a ring is meant a constituent atom of the skeleton of the ring. Thus, for example, a benzene ring comprises six members, each member being constituted by a carbon atom. In another example, a furan ring comprises five members, four members each being constituted by a carbon atom and the remaining member being constituted by an oxygen atom.
[0023] “CHO” represents the aldehyde function.
[0024] “CH2OH” represents the hydroxymethyl function.
[0025] By “aromatic polyphenol” is meant an aromatic compound comprising at least one benzene nucleus carrying more than one hydroxyl function.
[0026] By "resin based on", it is meant that the resin comprises the mixture and / or the reaction product of the different basic constituents used for this resin as defined above and that this resin is solely based on the constituents of the resin. Thus the basic constituents are the reactants intended to react together during the final condensation of the resin and are not reactants intended to react together to form these basic constituents.
[0027] According to the invention, the basic constituents of the aqueous adhesive composition therefore comprise at least one compound Al and at least one phenol A21. In one embodiment, the basic constituents may comprise other additional constituents different from the compound Al and the phenol A21. In another embodiment, the basic constituents consist of at least one compound Al and at least one phenol A21.
[0028] Preferably, in the embodiment where the base constituents comprise other additional constituents, these other additional constituents are free of formaldehyde and / or free of methylene donor selected from the group consisting of hexa-methylenetetramine (HMT), hexamethoxymethylmelamine (H3M), hexaethoxymethylmelamine, lauryloxymethylpyridinium chloride, ethoxymethylpyridinium chloride, hexamethoxymethylmelamine polymers of formaldehyde trioxane, rhexakis(methoxymethyl)melamine, N,N',N"-trimethyl / -N,N',N"-trimethylolmelamine, hexamethylolmelamine, N-methylolmelamine, N,N'-dimethylolmelamine, N,N',N"-tris(methoxymethyl)melamine, N,N',N"-tributyl-N,N',N"-trimethylolmelamine. More preferably, these other additional constituents are free of formaldehyde and free of the methylene donors described in this paragraph.
[0029] More preferably, in the embodiment where the basic constituents com take other additional constituents, these other additional constituents are free of formaldehyde and / or free of methylene donor chosen from the group consisting of hexamethylenetetramine, hexaethoxymethylmelamine, hexamethoxymethylmelamine, lauryloxymethylpyridinium chloride, ethoxymethylpyridinium chloride, trioxane hexamethoxymethylmelamine and N-substituted oxymethylmelamines corresponding to the general formula: in which Q represents an alkyl group containing from 1 to 8 carbon atoms; Fb F2, F3, F4 and F5 are selected, independently of one another, from the group consisting of a hydrogen atom, an alkyl group containing from 1 to 8 carbon atoms, the group -CH20Q and their condensation products. More preferably, these other additional constituents are free of formaldehyde and free of the methylene donors described in this paragraph.
[0030] Even more preferably, in the embodiment where the basic constituents comprise other additional constituents, these other additional constituents are free of formaldehyde and / or free of methylene donor. More advantageously, these other additional constituents are free of formaldehyde and free of methylene donors.
[0031] By formaldehyde-free or methylene donor-free, it is meant that the total mass content of formaldehyde or of the methylene donor(s) belonging to the groups described above by total weight of the compound(s) Al in the basic constituents is less than or equal to 10%, preferably 5%, more preferably 2% and even more preferably 1%.
[0032] By formaldehyde-free and methylene donor-free, it is meant that the total mass content of formaldehyde and of the methylene donor(s) belonging to the groups described above by total weight of the compound(s) Al in the basic constituents is less than or equal to 10%, preferably 5%, more preferably 2% and even more preferably 1%.
[0033] By CVR glass-resin composite strands, we mean composite reinforcements based on of single strands of the “CVR” type comprising continuous, unidirectional multifilament glass fibers, embedded in a thermoset resin and usable in particular as tire reinforcement elements.
[0034] METHOD ACCORDING TO THE INVENTION
[0035] A) pre-adhesion step
[0036] The pre-adhesion of the CVR strand(s) is carried out in a first bath based on epoxy and diisocyanate blocked in aqueous solution.
[0037] Advantageously, the epoxy compound is chosen from the group consisting of 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, poly-glycerol, polyglycidyl ether; pentaerythrithiol, polyglycidyl ether, diglycerol, polyglycidyl ether; sorbitol polyglycidyl ether or isosorbide diglycidyl ether and preferably is polyglycerol polyglycidyl ether.
[0038] Advantageously, the blocked diisocyanate compound is chosen from the group consisting of diphenylmethane diisocyanate or polyphenylene polymethylene polyisocyanate and preferably N,N'-(methylenedi-p-phenylene)bis[hexahydro-2-oxo-lH-azepine-l-carboxamide] 4,4'-diisocyanate.
[0039] Advantageously, this pre-adhesion step is followed by a step of drying the CVR composite at a temperature greater than or equal to 120°C for at least 5 seconds, then by a heat treatment at a temperature greater than or equal to 180°C for at least 5 seconds.
[0040] B) step of depositing the aqueous adhesive composition
[0041] An aqueous adhesive composition is then deposited on the pre-adhered CVR strand(s).
[0042] According to the invention, the basic constituents of the resin therefore comprise at least one compound Al and at least one phenol A2. In one embodiment, the basic constituents may comprise other additional constituents different from the compound Al and the phenol A2. In another embodiment, the basic constituents consist of at least one compound Al and at least one phenol A2.
[0043] According to the invention, the aqueous adhesive composition is prepared so that the blocked diisocyanate is at a mass content of the aqueous adhesive composition strictly less than or equal to 0.50%.
[0044] Preferably, the diisocyanate compound blocked in the aqueous adhesive composition of the second bath is at a mass content 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% and even more preferably less than or equal to 0.05%.
[0045] More preferably, the aqueous adhesive composition of the second bath is free of blocked diisocyanate.
[0046] Compound Al
[0047] An essential constituent of the adhesive composition is an Al compound, the Al compound comprising at least one aldehyde function.
[0048] According to the invention, the resin is based on at least one (i.e. one or more) Al compounds.
[0049] In a first embodiment, the compound Al is formaldehyde.
[0050] In a second embodiment, the compound Al comprises at least one aromatic nucleus carrying at least one aldehyde function.
[0051] More preferably, the compound Al carries at least two aldehyde functions.
[0052] Even more preferably, the aromatic nucleus of the compound Al carries two aldehyde functions.
[0053] In one embodiment, the aromatic nucleus of the compound Al is selected from the group consisting of a benzene nucleus and a furan nucleus, preferably the aromatic nucleus of the aromatic aldehyde is a benzene nucleus.
[0054] Preferably, the compound Al is chosen from the group consisting of 1,2-benzene-dicarboxaldehyde, 1,3-benzene-dicarboxaldehyde, 1,4-benzene-dicarboxaldehyde, 2-hydroxybenzene-1,3,5-tricarbaldehyde and mixtures of these compounds.
[0055] In a variant of the second embodiment, the compound Al is of general formula (A): in which:
[0056] X includes N, S or O R represents -H or -CHO. Preferably, the compound Al is of general formula (A'): in which X represents O. O
[0057]
[0058]
[0059] (HAS') Even more preferably, R represents -CHO. According to a preferred embodiment, X represents O. In a variant of the compound Al of general formula (A), X represents O and R represents -H. The compound Al used is then of formula (Ba): H
[0060] (Ba) In a variant of the aldehyde of general formula (A'), X represents O and R represents -H. The compound Al used is then furfuraldehyde and is of formula (B'a): O
[0061] In another variant of the compound Al of general formula (A), X represents O and R represents -CHO. The compound Al used is then of formula (Bb):
[0062] In another variant of the compound Al of general formula (A'), X represents O and R represents -CHO. The compound Al used is then 2,5-furanedicarboxaldehyde and is of formula (B'b):
[0063]
[0064]
[0065] In another embodiment, X comprises N. Preferably, compound Al is selected from the group consisting of furfuraldehyde, 2,5-furanedicarboxaldehyde and mixtures of these compounds. In a variant of the compound Al of general formula (A), X represents NH. The compound A12 used is of formula (Ca):
[0066] H (That) In a variant of the compound Al of general formula (A'), X represents NH. The compound A12 used is of formula (C'a):
[0067]
[0068]
[0069]
[0070] (That) Preferably, R represents -CHO in the variant of compound A12 of formula (C'a) and the compound A12 obtained is then 2,5-1H-pyrroledicarboxaldehyde. In another variant of compound Al of general formula (A), X represents NTi with Ti representing an alkyl, aryl arylalkyl, alkylaryl or cycloalkyl group. The compound A12 used is of formula (Cb): H (Cb) In another embodiment, X comprises S. In a variant of the compound Al of general formula (A), X represents S. The compound A12 used is of formula (Da):
[0071] In a variant of the compound Al of general formula (A'), X represents S. The compound A12 used is of formula (D'a): O (From)
[0072] Preferably, R represents -CHO in the variant of compound Al of formula (IV'a) and is then 2,5-thiophenedicarboxaldehyde.
[0073] In another variant of compound Al of general formula (A), X represents ST2 with T2 representing an alkyl, aryl arylalkyl, alkylaryl or cycloalkyl group. The compound A12 used is of formula (Db): L •e (Db)
[0074] In yet another variant of the compound Al of general formula (A), X represents T3-S-T2 with T2, T3 each independently of the other representing an alkyl, aryl arylalkyl, alkylaryl or cycloalkyl group. The compound Al used is of formula (De): ©s)
[0075] In yet another variant of the compound Al of general formula (A), X represents S=O. The compound A12 used is of formula (Dd): O rÔ^° H (Dd)
[0076] In yet another variant of the compound Al of general formula (A), X represents O=S=O. The compound A12 used is of formula (De):
[0077] Among the different embodiments described above, the embodiments and variants in which X represents NH, S or O will be preferred. In these embodiments and variants, R may represent -H or -CHO and preferably R represents -CHO. In these embodiments and variants, R will preferably be in position 5 and the -CHO group in position 2 on the aromatic nucleus (general formula (A')).
[0078] Phenol A21
[0079] According to the invention, the resin is based on at least one (i.e. one or more) phenol A21.
[0080] Advantageously, phenol A21 is chosen from: - an aromatic polyphenol A2 comprising at least one aromatic nucleus carrying at least two hydroxyl functions in the meta position, one by relative to each other, the two ortho positions of at least one of the hydroxyl functions being unsubstituted - an aromatic monophenol A2' comprising at least one six-membered aromatic ring carrying a single hydroxyl function, • the two ortho positions of the hydroxyl function being unsubstituted or • at least one ortho position and the para position of the hydroxyl function being unsubstituted - a mixture of A2 and A2'.
[0081] In one embodiment, the phenol is an aromatic polyphenol A2 comprising one or more aromatic nuclei. The aromatic polyphenol comprises at least one aromatic nucleus carrying at least two hydroxyl functions in meta position relative to each other, the two ortho positions of at least one of the hydroxyl functions being unsubstituted.
[0082] In another embodiment, the phenol is an aromatic monophenol A2' comprising at least one six-membered aromatic ring carrying a single hydroxyl function. On this aromatic monophenol, the two ortho positions of the hydroxyl function are unsubstituted, or at least one ortho position and the para position of the hydroxyl function are unsubstituted.
[0083] In yet another embodiment, the phenol is a mixture of the aromatic polyphenol A2 and the aromatic monophenol A2' as described above.
[0084] In accordance with the invention, the aromatic polyphenol A2 may be, in one embodiment, a simple molecule of aromatic polyphenol comprising one or more aromatic nuclei, at least one of these aromatic nuclei, or even each aromatic nucleus, carrying at least two hydroxyl functions in meta position relative to each other, the two ortho positions of at least one of the hydroxyl functions being unsubstituted.
[0085] Similarly, the aromatic monophenol A2' may be, in one embodiment, a simple molecule of aromatic monophenol comprising one or more six-membered aromatic rings, at least one of these six-membered aromatic rings, or even each six-membered aromatic ring, carrying a single hydroxyl function, the two ortho positions of the hydroxyl function being unsubstituted, or at least one ortho position and the para position of the hydroxyl function being unsubstituted.
[0086] Such simple molecules do not comprise a repeating unit.
[0087] According to the invention, the aromatic polyphenol A2 may be, in another embodiment, a pre-condensed resin based on: • at least one aromatic polyphenol, comprising at least one aromatic nucleus carrying at least two hydroxyl functions in the meta position relative to each other, the two ortho positions of at least one of the hydroxyl functions being unsubstituted; and • 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 nucleus.
[0088] Such a pre-condensed resin based on aromatic polyphenol is in accordance with the invention and comprises, unlike the simple molecule described above, a repeating unit. In this case, the repeating unit comprises at least one aromatic nucleus carrying at least two hydroxyl functions in the meta position relative to each other.
[0089] In a similar manner and in accordance with the invention, the aromatic monophenol A2' may be, in another embodiment, a pre-condensed resin based on: • at least one aromatic monophenol comprising at least one six-membered aromatic ring carrying a single hydroxyl function: - both ortho positions of the hydroxyl function are unsubstituted, or - at least one ortho position and the para position of the hydroxyl function are unsubstituted; • 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 nucleus.
[0090] Such a pre-condensed resin based on aromatic monophenol is in accordance with the invention and comprises, unlike the simple molecule described above, a repeating unit. In this case, the repeating unit comprises at least one six-membered aromatic ring carrying a single hydroxyl function.
[0091] In another embodiment, phenol A21 is a mixture of a single molecule aromatic polyphenol and a pre-condensed aromatic polyphenol resin.
[0092] In yet another embodiment, phenol A21 is a mixture of a single molecule aromatic monophenol and a pre-condensed aromatic monophenol resin.
[0093] In the following particular embodiments, the aromatic nucleus(s) of the aromatic polyphenol and / or aromatic monophenol are described. For the sake of clarity, the “aromatic polyphenol” and / or “aromatic monophenol” are described in their single molecule form. This aromatic polyphenol and / or aromatic monophenol may then be condensed and will partly define the repeating unit. The characteristics of the pre-condensed resin are described in more detail below.
[0094] Aromatic polyphenol A2
[0095] In a preferred embodiment, the aromatic nucleus of the aromatic polyphenol carries three hydroxyl functions in meta position relative to each other.
[0096] Preferably, the two ortho positions of each hydroxyl function are unsubstituted. This means that the two carbon atoms located on either side (in the ortho position) of the hydroxylated carbon atom (i.e., carrying the hydroxyl function) carry a single hydrogen atom.
[0097] Even more preferably, the remainder of the aromatic nucleus of the aromatic polyphenol is unsubstituted. This means that the other carbon atoms of the remainder of the aromatic nucleus (those other than the carbon atoms carrying the hydroxyl functions) carry a single hydrogen atom.
[0098] In one embodiment, the aromatic polyphenol comprises several aromatic nuclei, at least two of which each carry at least two hydroxyl functions in the meta position relative to each other, the two ortho positions of at least one of the hydroxyl functions of at least one aromatic nucleus being unsubstituted.
[0099] In a preferred embodiment, at least one of the aromatic nuclei of the aromatic polyphenol carries three hydroxyl functions in meta position relative to each other.
[0100] Preferably, the two ortho positions of each hydroxyl function of at least one aromatic nucleus are unsubstituted.
[0101] Even more preferably, the two ortho positions of each hydroxyl function of each aromatic nucleus are unsubstituted.
[0102] Advantageously, the or each aromatic nucleus of the aromatic polyphenol is a benzene nucleus.
[0103] As an example of an aromatic polyphenol comprising a single aromatic nucleus, mention may be made in particular of resorcinol and phloroglucinol, as a reminder of the developed formulae (IV) and (V) respectively: cm!
[0104] By way of example, in the case where the aromatic polyphenol comprises several aromatic nuclei, at least two of these aromatic nuclei, identical or different, are chosen from those of general formulas: in which the symbols Zb Z2, identical or different if there are several on the same aromatic nucleus, represent an atom (for example carbon, sulfur or oxygen) or a linking group by definition at least divalent, which links at least these two aromatic nuclei to the rest of the aromatic polyphenol.
[0105] Another example of an aromatic polyphenol is 2,2',4,4'-tetrahydroxydiphenyl sulfide of the following structural formula (VII): UH OH (Vil)
[0106] Another example of an aromatic polyphenol is 2,2',4,4'-tetrahydroxydiphenyl benzophenone of the following structural formula (VIII):
[0107] It is noted that each compound VII and VIII is an aromatic polyphenol comprising two aromatic nuclei (of formulas VI-c) each of which carries at least two (in this case two) hydroxyl functions in the meta position relative to each other.
[0108] It is noted that in the case of an aromatic polyphenol comprising at least one aromatic nucleus in accordance with the formula VI-b, the two ortho positions of each hydroxyl function of at least one aromatic nucleus are unsubstituted. In the case of an aromatic polyphenol comprising several aromatic nuclei in accordance with the formula VI-b, the two ortho positions of each hydroxyl function of each aromatic nucleus are unsubstituted.
[0109] According to one embodiment of the invention, the aromatic polyphenol is chosen from the group consisting of resorcinol, phloroglucinol, 2,2',4,4'-tetrahydroxydiphenyl sulfide, 2,2',4,4'-tetrahydroxybenzophenone, and mixtures of these compounds.
[0110] In a particularly advantageous embodiment, the aromatic polyphenol is phloroglucinol.
[0111] In one embodiment, the aromatic polyphenol A2 comprises a precondensed resin based on the aromatic polyphenol as described in any of these embodiments.
[0112] This pre-condensed resin is advantageously based on: • at least one aromatic polyphenol as defined above, and preferably chosen from the group consisting of resorcinol, phloroglucinol, 2,2',4,4'-tetrahydroxydiphenyl sulfide, 2,2',4,4'-tetrahydroxybenzophenone, and mixtures thereof; and • at least one compound capable of reacting with the aromatic polyphenol comprising at least one aldehyde function and / or at least one compound capable of reacting with the aromatic polyphenol comprising at least two hydroxymethyl functions, and preferably an aromatic aldehyde comprising at least one aromatic nucleus carrying at least one aldehyde function.
[0113] The compound capable of reacting with the aromatic polyphenol with the compound Al may be an aromatic compound as defined above or any other aldehyde. Advantageously, said compound is chosen from the group consisting of an aromatic compound comprising an aromatic nucleus carrying at least two functions, one of these functions being a hydroxymethyl function, the other being an aldehyde function or a hydroxymethyl function, formaldehyde, furfuraldehyde, 2,5-furanedicarboxaldehyde, 1,4-benzenedicarboxaldehyde, 1,3-benzenedicarboxaldehyde, 1,2-benzenedicarboxaldehyde and mixtures of these compounds.Very advantageously, when the compound capable of reacting with the aromatic polyphenol is an aromatic compound comprising an aromatic nucleus carrying at least two functions, one of these functions being a hydroxymethyl function, the other being an aldehyde function or a hydroxymethyl function, this compound is chosen from the group consisting of 5-(hydroxymethyl)-furfural, 2,5-di(hydroxymethyl)furan and mixtures of these compounds.
[0114] Thus, in the pre-condensed resin based on aromatic polyphenol, the repeating unit meets the characteristics of the aromatic polyphenol defined previously except that at least one of the carbon atoms of the aromatic nucleus, which was unsubstituted, is linked to another unit.
[0115] Regardless of the compound other than the aromatic polyphenol at the base of the pre-condensed resin, this pre-condensed resin is free of free formaldehyde. In fact, even in the case where the pre-condensed resin is based on an aromatic polyphenol as described above and formaldehyde, the formaldehyde having already reacted with the aromatic polyphenol, the pre-condensed resin is free of free formaldehyde capable of reacting with a compound Al in accordance with the invention in a subsequent step.
[0116] The aromatic polyphenol A2 may also comprise a mixture of a free molecule of aromatic polyphenol and a pre-condensed resin based on aromatic polyphenol, as described above. In particular, the aromatic polyphenol A2 may also comprise a mixture of phloroglucinol and a pre-condensed resin based on phloroglucinol.
[0117] Aromatic monophenol A2'
[0118] The aromatic monophenol A2' may be in accordance with two variants. In one variant, both ortho positions of the hydroxyl function are unsubstituted. In another variant, at least one ortho position and the para position of the hydroxyl function are unsubstituted.
[0119] Advantageously, in the variant in which at least one ortho position and the para position of the hydroxyl function are unsubstituted, a single ortho position is unsubstituted and the para position of the hydroxyl function is unsubstituted.
[0120] Preferably, whatever the variant, the two ortho positions of the hydroxyl function are unsubstituted. This means that the two carbon atoms located on either side (in the ortho position) of the hydroxylated carbon atom (i.e., carrying the hydroxyl function) carry a single hydrogen atom.
[0121] Even more preferably, the remainder of the aromatic nucleus is unsubstituted. This means that the other carbon atoms of the remainder of the aromatic nucleus (those other than the carbon atoms carrying the hydroxyl functions) carry a single hydrogen atom.
[0122] In one embodiment, the aromatic monophenol comprises several six-membered aromatic rings, at least two of which each carry a single hydroxyl function and, for at least one of the hydroxyl functions, both ortho positions of the hydroxyl function are unsubstituted, or at least one ortho position and the para position of the hydroxyl function are unsubstituted.
[0123] Preferably, both ortho positions of each hydroxyl function of at least one six-membered aromatic ring are unsubstituted.
[0124] Even more preferably, the two ortho positions of each hydroxyl function of each six-membered aromatic ring are unsubstituted.
[0125] Even more preferably, the remainder of each of the aromatic nuclei is unsubstituted. This means that the other carbon atoms of the remainder of each aromatic nucleus (those other than the carbon atoms carrying the hydroxyl or carriers of the group linking the aromatic nuclei together) carry a single hydrogen atom.
[0126] Advantageously, the or each aromatic nucleus of the aromatic monophenol is a benzene nucleus.
[0127] Preferably, the aromatic monophenol is selected from the group consisting of phenol, ortho cresol, meta cresol, para cresol, ortho chlorophenol, meta chlorophenol, para chlorophenol, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 4-vinylphenol, 4-ethylphenol, 4-isopropylphenol, 4-isobutylphenol, paracoumaric acid and mixtures of these compounds.
[0128] In one embodiment, the aromatic monophenol A2' comprises a pre-condensed resin based on the aromatic monophenol as described in any of these embodiments.
[0129] This pre-condensed resin is advantageously based on: • at least one aromatic monophenol as defined above, and preferably chosen from the group consisting of phenol, ortho cresol, meta cresol, para cresol, ortho chlorophenol, meta chlorophenol, para chlorophenol, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 4-vinylphenol, 4-ethylphenol, 4-isopropylphenol, 4-isobutylphenol, paracoumaric acid and mixtures of these compounds; and • at least one compound capable of reacting with the aromatic monophenol comprising at least one aldehyde function and / or at least one compound capable of reacting with the aromatic monophenol comprising at least two hydroxymethyl functions, and preferably an aromatic aldehyde comprising at least one aromatic nucleus carrying at least one aldehyde function.
[0130] The compound capable of reacting with the aromatic monophenol may be a compound Al as defined above or any other aldehyde. Advantageously, said compound capable of reacting with the aromatic polyphenol is chosen from the group consisting of an aromatic compound comprising an aromatic nucleus carrying at least two functions, one of these functions being a hydroxymethyl function, the other being an aldehyde function or a hydroxymethyl function, formaldehyde, furfuraldehyde, 2,5-furanedicarboxaldehyde, 1,4-benzenedicarboxaldehyde, 1,3-benzenedicarboxaldehyde, 1,2-benzenedicarboxaldehyde and mixtures of these compounds. Very advantageously, when the compound is an aromatic compound comprising an aromatic nucleus carrying at least two functions, one of these functions being a hydroxymethyl function, the other being an aldehyde function or a hydroxymethyl function, this compound is selected from the group consisting of 5-(hydroxymethyl)-furfural, 2,5-di(hydroxymethyl)furan and mixtures of these compounds.
[0131] Thus, in the pre-condensed aromatic monophenol resin, the repeating unit meets the characteristics of the aromatic monophenol defined previously except that at least one of the carbon atoms of the six-membered aromatic ring, which was unsubstituted, is linked to another unit.
[0132] Whatever the compound other than the aromatic monophenol at the base of the pre-condensed resin, this pre-condensed resin is free of free formaldehyde. Indeed, even in the case where the pre-condensed resin is based on an aromatic monophenol as described above and formaldehyde, the formaldehyde having already reacted with the aromatic monophenol, the pre-condensed resin is free of free formaldehyde capable of being able to react with a compound Al in accordance with the invention in a subsequent step.
[0133] The aromatic monophenol A2' may also comprise a mixture of a free molecule of aromatic monophenol and a pre-condensed resin based on aromatic monophenol, as described above. In particular, the aromatic monophenol A2' may also comprise a mixture of phenol and a pre-condensed resin based on phenol.
[0134] Mixture of aromatic polyphenol A2 and aromatic monophenol A2'
[0135] Phenol A21 may also comprise a mixture of an aromatic polyphenol A2 and an aromatic monophenol A2', as described above.
[0136] Preferably, phenol A21 comprises a mixture of aromatic polyphenol and a pre-condensed aromatic polyphenol-based resin.
[0137] Elastomer latex
[0138] The adhesive composition also comprises an elastomer latex, preferably unsaturated. Such an elastomer latex makes it possible to provide an elastomeric physical interface when the adhesive composition is used for coating elements intended to be embedded in an elastomer matrix. When the elastomer latex is unsaturated, it also provides a chemical interface thanks to the unsaturations capable of forming bridges with the crosslinking system of the elastomer matrix.
[0139] It is recalled that a latex is a stable dispersion of microparticles of elastomer(s) suspended in a generally aqueous solution. An elastomer latex is therefore a composition in a liquid state comprising a liquid solvent, generally water, and at least one elastomer or rubber dispersed in the liquid solvent so as to form a suspension. Thus, the latex is not a rubber composition which comprises an elastomer or rubber matrix in which is dispersed at least minus one other component. A rubber composition is in a plastic state when raw (uncrosslinked) and in an elastic state when cured (crosslinked) but in no case in a liquid state like a latex.
[0140] Unsaturated elastomer latexes (i.e. those bearing carbon-carbon double bonds), in particular diene elastomer latexes, are well known to those skilled in the art. They constitute in particular the elastomeric base of the RFL adhesives described in the introduction to this document.
[0141] The unsaturated elastomer of the latex is preferably a diene elastomer, more preferably a diene elastomer chosen from the group consisting of butadiene copolymers, styrene-butadiene copolymers, vinyl-pyridine-styrene-butadiene terpolymers, natural rubber with the exception of chlorinated natural rubber, and mixtures of these elastomers.
[0142] Advantageously, this step of depositing the aqueous adhesive composition is followed by a step of drying the CVR composite at a temperature greater than or equal to 120° for at least 5 seconds, then by a heat treatment at a temperature greater than or equal to 180°C for at least 5 seconds.
[0143] COMPOSITE ACCORDING TO THE INVENTION
[0144] The invention also relates to an elastomer composite reinforced with at least one or more strands of bonded Glass-Resin CVR composite as defined above. The elastomer matrix is based on an elastomer composition comprising at least one elastomer and one other constituent.
[0145] Preferably, the elastomer composition comprises a diene elastomer. By elastomer or rubber (the two terms being synonymous) of the "diene" type, is generally meant an elastomer derived at least in part (i.e. a homopolymer or a copolymer) from diene monomers (monomers bearing two carbon-carbon double bonds, conjugated or not).
[0146] The elastomer compositions may contain a single diene elastomer or a mixture of several diene elastomers, the diene elastomer(s) being able to be used in association with any type of synthetic elastomer other than diene, or even with polymers other than elastomers, for example thermoplastic polymers.
[0147] In a first embodiment preferably intended for pneumatic use, the elastomer composition comprises a diene elastomer chosen from the group consisting of polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), different butadiene copolymers, different isoprene copolymers, and mixtures of these elastomers.
[0148] Such copolymers are more preferably chosen from the group consisting of butadiene-styrene copolymers (SBR), whether the latter are prepared by poly emulsion (ESBR) and solution (SSBR) merization, isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR) and isoprene-butadiene-styrene copolymers (SBIR).
[0149] In a second embodiment preferably intended for belt use, the elastomer composition comprises an elastomer selected from the group consisting of an ethylene alpha olefin elastomer, a polychloroprene elastomer and mixtures of these elastomers, one or more other elastomers. The elastomer composition may also comprise one or more other components.
[0150] Advantageously, the ethylene alpha olefin type elastomer is chosen from the group consisting of ethylene-propylene copolymers (EPM), ethylene-propylene-diene copolymers (EPDM) and mixtures of these copolymers.
[0151] Preferably, the elastomer composition comprises a reinforcing filler.
[0152] When a reinforcing filler is used, any type of reinforcing filler known for its ability to reinforce an elastomer composition suitable for the manufacture of tires may be used, for example an organic filler such as carbon black, a reinforcing inorganic filler such as silica, or a blend of these two types of filler, in particular a blend of carbon black and silica.
[0153] Suitable carbon blacks are all carbon blacks conventionally used in tires (so-called tire grade blacks). For example, reinforcing carbon blacks of the 100, 200 or 300 series (ASTM grades) will be mentioned in particular.
[0154] In the case of using carbon blacks with an isoprene elastomer, the carbon blacks could for example already be incorporated into the isoprene elastomer in the form of a masterbatch (see for example applications WO 97 / 36724 or WO 99 / 16600).
[0155] Examples of organic fillers other than carbon blacks that may be mentioned are functionalized polyvinylaromatic organic fillers as described in applications WO-A-2006 / 069792 and WO-A-2006 / 069793.
[0156] By "reinforcing inorganic filler" is meant in the present application, by definition, any inorganic or mineral filler (whatever its color and origin (natural or synthetic)), also called "white" filler, "light" filler or even "non-black filler" as opposed to carbon black, capable of reinforcing on its own, without any other means than an intermediate coupling agent, an elastomer composition, in other words capable of replacing, in its reinforcing function, a conventional tire-grade carbon black. Such a filler is generally characterized, in a known manner, by the presence of hydroxyl groups (-OH) on its surface.
[0157] The physical state in which the reinforcing inorganic filler is present is indifferent, whether in the form of powder, micro-beads, granules, beads or any other suitable densified form. Of course, the term reinforcing inorganic filler also means mixtures of different reinforcing inorganic fillers, in particular highly dispersible siliceous and / or aluminous fillers as described below.
[0158] Suitable reinforcing inorganic fillers include, in particular, mineral fillers of the siliceous type, in particular silica (SiO2), or of the aluminous type, in particular alumina (A12O3). The silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenic silica having a BET surface area and a CTAB specific surface area both less than 450 m2 / g, preferably from 30 to 400 m2 / g. Examples of highly dispersible precipitated silicas (known as "HDS") include "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, and high specific surface silicas as described in application WO 03 / 16837.
[0159] Finally, those skilled in the art will understand that, as a filler equivalent to the reinforcing inorganic filler described in this paragraph, a reinforcing filler of another nature, in particular organic, could be used, provided that this reinforcing filler is covered with an inorganic layer such as silica, or else comprises functional sites on its surface, in particular hydroxyl, requiring the use of a coupling agent to establish the bond between the filler and the elastomer.
[0160] Preferably, the level of total reinforcing filler (carbon black and / or reinforcing inorganic filler such as silica) is within a range of 5 to 120 phr, more preferably 5 to 100 phr and even more preferably 5 to 90 phr.
[0161] Carbon black can advantageously constitute the only reinforcing filler or the majority reinforcing filler. Of course, a single carbon black or a blend of several carbon blacks of different ASTM grades can be used. Carbon black can also be used in blends with other reinforcing fillers and in particular reinforcing inorganic fillers as described above, and in particular silica.
[0162] When an inorganic filler (for example silica) is used in the rubber composition, alone or in a blend with carbon black, its content is within a range of 0 to 70 phr, preferably from 0 to 50 phr, in particular also from 5 to 70 phr, and even more preferably this proportion varies from 5 to 50 pce, especially 5 to 40 pce.
[0163] Preferably, the elastomer composition comprises various additives.
[0164] The rubber compositions may also comprise all or part of the usual additives usually used in elastomer compositions intended for the manufacture of tires, such as for example plasticizers or extender oils, whether the latter are of an aromatic or non-aromatic nature, pigments, protective agents such as anti-ozone waxes, chemical anti-ozonants, antioxidants, anti-fatigue agents or even adhesion promoters.
[0165] Preferably, the elastomer composition comprises a crosslinking system, more preferably a vulcanization system.
[0166] In the first embodiment preferably intended for pneumatic use, the elastomer composition comprises a vulcanization system.
[0167] The vulcanization system comprises a sulfur donor agent, for example sulfur.
[0168] Preferably, the vulcanization system comprises vulcanization activators such as zinc oxide and stearic acid.
[0169] Preferably, the vulcanization system comprises a vulcanization accelerator and / or a vulcanization retarder.
[0170] Advantageously, the composite is such that the elastomer matrix is based on an elastomer composition comprising a crosslinking system comprising a molecular sulfur content ranging from 1 to 5 phr. By molecular sulfur is meant sulfur derived from a Sn compound with n>2. Indeed, the inventors hypothesize that there is competition between adhesion by the adhesive composition and adhesion by the copper and zinc sulfide dendrites. However, this competition tends to reduce the general level of adhesion. The more the sulfur content present in the elastomer matrix is reduced, the more this competition is reduced, the more the level of adhesion by the adhesive composition alone is promoted.
[0171] Very advantageously, the molecular sulfur content of the crosslinking system of the elastomer composition is less than or equal to 4 phr, preferably 3 phr and more preferably 2.5 phr. In addition to further reducing the competition between adhesion by the adhesive composition and adhesion by the copper and zinc sulfide dendrites, the storage life of the elastomer composition at room temperature is improved by avoiding the risks of pre-vulcanization which would occur if a higher sulfur content were used.
[0172] Very advantageously, the molecular sulfur content of the crosslinking system of the elastomer composition is greater than or equal to 1.5 pce, preferably 2 pce.
[0173] The sulfur level is measured by elemental analysis, using the Thermo Scientific Flash 2000 micro-analyzer. The analysis includes a combustion step of the sample and then a step of separation of the compounds formed. Approximately 1 mg of sample is introduced into the micro-analyzer, where it undergoes a flash combustion of 1000°C under oxygen. The gases formed are then oxidized using excess oxygen and a tungstic anhydride catalyst. A reduction step by passage over copper then allows the excess oxygen to be trapped, and the nitrogen oxides to be reduced to N2 as well as the sulfites to sulfur dioxide SO2. The water is trapped and the N2, CO2, SO2 compounds formed are then separated on a chromatographic column and then detected by a katharometer. The quantification of total sulfur is carried out by measuring the area of the SO2 peak, after calibration with standards.
[0174] All vulcanization accelerators, retarders and activators are used at a preferential rate within a range of 0.5 to 15 pce. The vulcanization activator(s) is(are) used at a preferential rate within a range of 0.5 to 12 pce.
[0175] The actual crosslinking system is preferably based on sulfur and a primary vulcanization accelerator, in particular an accelerator of the sulfenamide type. In addition to this vulcanization system, various known secondary accelerators or vulcanization activators such as zinc oxide, stearic acid, guanidine derivatives (in particular diphenylguanidine), etc. are added.
[0176] Any compound capable of acting as an accelerator (primary or secondary) for the vulcanization of diene elastomers in the presence of sulfur, in particular accelerators of the thiazole type and their derivatives, accelerators of the thiuram type, and of the zinc dithiocarbamate type, may be used as accelerator (primary or secondary). These accelerators are more preferably selected from the group consisting of 2-mercaptobenzothiazyl disulfide (abbreviated as "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide (abbreviated as "CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide (abbreviated as "DCBS"), N-tert-butyl-2-benzothiazyl sulfenamide (abbreviated as "TBBS"), N-tert-butyl-2-benzothiazyl sulfenimide (abbreviated as "TBSI"), zinc dibenzyldithiocarbamate (abbreviated as "ZBEC") and mixtures of these compounds. Preferably, a primary accelerator of the sulfenamide type is used.
[0177] In the second embodiment preferably intended for belt use, the crosslinking system is substantially free of sulfur, and advantageously comprises a peroxide, preferably an organic peroxide. Advantageously, the peroxide level ranges from 0.5 to 8 phr. Advantageously, the crosslinking system comprises a co-crosslinking agent, preferably sulfur or triallyl cyanurate. Advantageously, the level of the co-crosslinking agent ranges from 0.5 to 5 phr.
[0178] TYRE ACCORDING TO THE INVENTION
[0179] The invention also relates to a tire. The elastomer composite of the invention can advantageously be used for reinforcing tires of all types of vehicles, in particular passenger vehicles or industrial vehicles such as heavy goods vehicles.
[0180] BELT ACCORDING TO THE INVENTION
[0181] The invention also relates to a belt. For example, such a belt may be a power transmission belt.
[0182] The invention will be better understood on reading the description which follows, given solely by way of non-limiting example and made with reference to the drawings in which: • [Fig.l] is a diagram of a tire according to the invention; and • [Fig.2] is a schematic representation of the process for gluing one or more strands of CVR comprising steps of a process according to the invention.
[0183] The attached [Fig.l] represents very schematically (without respecting a specific scale), a radial section of a tire according to the invention for a passenger vehicle.
[0184] 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 with a bead wire 5. The crown 2 is surmounted by a tread not shown in this schematic figure. A carcass reinforcement 7 is wound around the two bead wires 5 in each bead 4, the turn-up 8 of this reinforcement 7 being for example arranged towards the outside of the tire 1 which is here shown mounted on its rim 9.The carcass reinforcement 7 is, in a manner known per se, made up of at least one ply reinforced by so-called "radial" cables, for example textiles, that is to say that these cables are arranged practically 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 median circumferential plane (plane perpendicular to the axis of rotation of the tire which is located midway between the two beads 4 and passes through the middle of the crown reinforcement 6).
[0185] This tire 1 of the invention has for example the essential characteristic that at least one crown reinforcement 6 and / or the carcass reinforcement 7 comprises the elastomer composite according to the invention. The tire has the preferential characteristic that at least its belt and / or its carcass reinforcement comprises a multi-layer laminate according to the invention, consisting of at least one multi-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 of the invention can be used in the form of parallel sections arranged under the tread, as described in patent EP 1 167 080. According to another possible embodiment of the invention, it is the bead zone which can be reinforced with such a composite; it is for example the bead wires which could be made, in all or part of a composite according to the invention.
[0186] The belt according to the invention has, for example, the essential characteristic that it comprises an elastomer composite according to the invention.
[0187] Of course, the invention relates to the objects previously described, namely the elastomer composite such as the tire or belt comprising it, both in the raw state (before crosslinking) and in the cured state (after crosslinking).
[0188] [Fig.2] shows an embodiment of an installation for gluing one or more strands of CVR according to the invention, designated by the general reference 30.
[0189] The manufacturing installation 30 is capable of manufacturing one or more strands of glued CVR.
[0190] The installation 30 comprises, in the direction of travel of the CVR strand(s) in the installation 30, from upstream to downstream, means 34 for upstream storage of the CVR strands, a first aqueous pre-adherization bath 36 comprising a composition based on an epoxy compound and a blocked diisocyanate compound in which the CVR strand(s) are soaked, a device 40 for drying by heat treatment of the pre-adhered strands, a second bath 42 consisting of an aqueous adhesive composition for depositing this adhesive composition on the CVR strands, a device 44 for heat treatment of the glued CVR strands and means 46 for downstream storage of the heat-treated glued CVR.
[0191] The upstream 34 and downstream 46 storage means each comprise a storage reel for the CVR strands allowing the CVR strands to be unwound and wound respectively.
[0192] We will now describe an example of a process for bonding one or more strands of CVR Glass-Resin composite.
[0193] During this process, a pre-adhesion step is carried out in a first bath based on an epoxy resin and a blocked diisocyanate in aqueous solution, for example based on polyglycerol polyglycidyl ether and 4,4'-diisocyanate of N,N'-(methylenedi-p-phenylene)bis[hexahydro-2-oxo-lH-azepine-l-carboxamide. The ingredients are introduced into the water with stirring, for example in the following order: 1.5 percent by weight of polyglycerol polyglycidyl ether (e.g., "Denacol EX-512" from Nagase Chemicals), 0.02% of zinc acetate, 0.08% of antifoaming agent, 15.15% of a 50% solution of N,N'-(methylenedi-p-phenylene)bis[hexahydro-2-oxo-1H-azepine-1-carboxamide]-4,4'-diisocyanate and 83.6% by weight of water.
[0194] To do this, several strands of CVR Glass-Resin composite are brought into contact with the first bath.
[0195] Then, the strands of Glass-Resin CVR composite are dried, for example, by passing in a high-frequency heating oven or tunnel (e.g. for 20 s at 170°C) and they undergo heat treatment (e.g. for 30 s at 220°C).
[0196] Next, a step of depositing the aqueous adhesive composition comprising water, a mixture of unsaturated elastomer latex and a resin based on phloroglucinol and 1,4-benzenedicarboxaldehyde is carried out. The proportions of these different constituents are described below.
[0197] To do this, several strands of Glass-Resin CVR composite are brought into contact with the adhesive composition. To do this, the strand of Glass-Resin CVR composite is continuously unwound from the storage reel of the storage means 34 and the strands of Glass-Resin CVR composite are passed through the first bath, then they pass into a heat treatment device then into a second bath comprising the aqueous adhesive composition and they pass into a heat treatment device for example by passing through a heating oven or tunnel (for example for 20 s at 170°C) and they undergo a heat treatment (for example for 30 s at 220°C).
[0198] COMPARATIVE TESTS
[0199] Adhesion test
[0200] Different control glued Glass-Resin CVR composite strands T, Tl, Tl', T2 and T2' and glued Glass-Resin CVR composite strands Cl and C2 according to the invention were tested by means of a test aimed at measuring the tearing force of these glued Glass-Resin CVR composite strands embedded in an elastomeric matrix.
[0201] The Glass-Resin CVR composite strands were coated with each of the protocols described below in Table 1 below, then dried in a drying oven at 170°C for 20s. Then the adhesive composition was crosslinked by passing the Glass-Resin CVR composite strands through a treatment oven at 220°C for 30s. Then the assembly was bonded by curing with a natural rubber composition, using a vulcanization heat treatment, to form composite specimens as described below.
[0202] The quality of the bond between the rubber composition and the Glass-Resin CVR composite strands is then determined by a test in which the force required to extract sections of Glass-Resin CVR composite strands from the vulcanized rubber composition is measured. This rubber composition is a conventional composition that can be used for calendering tire carcass reinforcement plies, these plies comprising Glass-Resin CVR composite strands embedded in an elastomeric matrix based on natural rubber, carbon black and the usual additives.
[0203] More precisely, the vulcanizate is a block of an elastomeric composition consisting of two plates measuring 200 mm by 4.5 mm and 3.5 mm thick, applied one on top of the other before curing (the thickness of the resulting block is then 7 mm). It is during the production of this block that the strands of Glass-Resin CVR composite (15 sections in total) are trapped between the two plates of the elastomeric composition in the raw state, at equal distances and leaving protruding on either side of these plates a cable end of sufficient length for subsequent traction. The block comprising the strands of Glass-Resin CVR composite is then placed in a suitable mold and then pressure-cured. The temperature and curing time are adapted to the target test conditions and left to the discretion of the person skilled in the art; for example, in the present case, the curing of the block is carried out at 160°C for 15 min.
[0204] At the end of the curing, the test piece thus constituted from the vulcanized block and the 15 sections of strands of CVR Glass-Resin composite is placed in the jaws of a traction machine adapted to allow each section to be tested in isolation, at a given speed and temperature (for example, in the present case, at 100 mm / min and 20°C).
[0205] The adhesion levels are characterized by measuring the so-called tear force (denoted FmaxO) to tear the strands of Glass-Resin CVR composite from the test piece. For the tear force (FmaxO), an adhesion value of 100 was set for the control T which represents the conventional gluing process for glass-resin composites as described in application WO2016116457.
[0206] The results of the adhesion tests carried out on the bonded CVR Glass-Resin composite strands are summarized in Table 1 below.
[0207] Humidity sensitivity test
[0208] Each strand of Glass-Resin CVR composite was coated with the tested adhesive composition according to the method described below in Table 1 with or without a first bath. Each strand of glued Glass-Resin CVR composite was dried in a drying oven at 170°C for 20 seconds. Then, the adhesive composition was crosslinked by passing the glued Glass-Resin CVR composite strands through a treatment oven at 220°C for 30 seconds.
[0209] The resistance of the interface to humid conditions is characterized by measuring the breaking force of the bonded Glass-Resin CVR composite strands (denoted FmaxO) and the breaking force of the bonded Glass-Resin CVR composite strands after baking for 70 hours at 90°C and 90% humidity (denoted Fmax70). The breaking force FmaxO is arbitrarily set at 100. The value of the breaking force Fmax70 of each bonded Glass-Resin CVR composite strand is necessarily less than 100, especially since the bonded Glass-Resin CVR composite strand has been sensitive to humid conditions.
[0210] The decay D, expressed in %, corresponding to the loss of breaking strength between FmaxO and Fmax70, was calculated. D is such that D= (1-Fmax70 / FmaxO) x 100. The higher the The lower the value of decay D, the lower the sensitivity of the bonded Glass-Resin CVR composite strand to humid conditions.
[0211] The results of the wet sensitivity tests carried out on the strands of Glass-Resin composite CVR bonded are summarized in Table 1 below.
[0212] The values of the different compounds are in % by mass of dry extract for a formula based on 100 for the first and second baths.
[0213] [Tables 1] Glass-Resin Composite Strand Bonded CVR T Tl Tl' Cl T2” C2 T2 T2' 1st Bath Epoxy(l) 1.15 0.5 - 1.15 1.15 1.15 0.5 - Blocked Diisocyanate (2) 15.15 - - 15.15 15.15 15.15 - - Zinc Acetate 0.02 - - 0.02 0.02 0.02 - - Soda - 0.06 - - - - 0.06 - Water 83.6 98.8 - 83.6 83.6 83.6 98.8 - 2nd Bath Al Compound 1,4-benzenedicarboxaldehyde (3) - - - - 0.9 0.9 0.9 0.9 Aldehyde Formaldehyde (4) 3.3 3.3 3.3 3.3 - - - - Compound A2 Phloroglucinol (5) - - - - 1.7 1.7 1.7 1.7 Resorcinol (6) 1.9 1.9 1.9 1.9 - - - - Other compounds Sodium hydroxide 0.1 0.1 0.1 0.1 0.8 0.8 0.8 0.8 Blocked diisocyanate (2) 9.7 9.7 9.7 0 9.7 0 0 0 Ammonia 2.6 2.6 2.6 2.6 2.6 2.5 2.5 2.5 Vinylpyridine-styrene-butadiene terpolymer 41.5 41.5 41.5 41.5 41.5 39.5 39.5 39.5 Water 41.0 41.0 41.0 50.6 42.7 54.6 54.6 54.6 Adhesion test FmaxO 100 146 103 85 85 72 65 74 Moisture sensitivity test D (%) 27 26 53 25 34 28 66 76 1. 2. polyglycerol polyglycidyl ether (EX512 supplied by Nagase) DiNCO 4,4'-diphenylmethylene diisocyanate ([Grilbond IL-6 50% supplied byEMS]) 3. 1,4-benzenedicarboxaldehyde (from ABCR; 98% purity); 4. Formaldehyde (from Caldic; diluted to 36%) 5. Phloroglucinol (from Alfa Aesar; 99% purity); 6. Resorcinol (Sumitomo CHIBA)
[0214] It is noted that the level of adhesion remains high regardless of the first bath used, and even without a first bath (TT).
[0215] It is noted that the composites according to the invention C1 and C2 have a breaking strength FmaxO which is certainly lower than the controls T, Tl, Tl' and T2” using diisocyanates blocked in the second bath, but nevertheless sufficient to ensure satisfactory adhesion and compatible with use in tires or belts.
[0216] It is also noted that the presence of blocked diisocyanate in the first bath limits the decay and this is true whatever the 2nd bath used (T, T2”, Cl and C2) and that the presence of diisocyanate has an effect on the resistance to humid conditions if we compare Tl to Cl and T2 to C2.
[0217] The presence of blocked diisocyanate therefore has an effect on moisture resistance.
[0218] Thus, the pre-adhesion step is an essential step to, on the one hand, maintain a good level of initial adhesion and, on the other hand, guarantee high resistance to humid conditions of the adhesive interface, without using products which have a negative impact on the environment.
[0219] The method according to the invention therefore makes it possible to make the composite C2 according to the invention adhere satisfactorily to the elastomer matrices without the latter requiring the use of an adhesive composition in association with products which have a negative impact on the environment. In addition, the adhesion of this composite is relatively high and is little degraded by humid conditions.
[0220] The invention is not limited to the embodiments previously described.
Claims
Claims
1. Method for bonding one or more strands of Glass-Resin composite, abbreviated to "CVR", characterized in that it comprises the following steps: a) a step of pre-adhesion of one or more strands of CVR composite is carried out by dipping the strand(s) in a first aqueous bath comprising a composition based on: - an epoxy compound; and - a blocked diisocyanate compound; b) a step of deposition on the strand(s) of CVR composite is carried out by dipping the strand(s) of CVR composite in a second bath comprising an aqueous adhesive composition based on: - at least one Al compound, the Al compound comprising at least one aldehyde function; - at least one phenol A21;- at least one unsaturated elastomer latex comprising at least one elastomer chosen from the group consisting of butadiene copolymers, styrene-butadiene copolymers, vinylpyridine-styrene-butadiene terpolymers, natural rubber with the exception of chlorinated natural rubber, and mixtures of these elastomers; the content of blocked diisocyanate compound in the aqueous adhesive composition of the second bath being at a mass rate strictly less than 0.50%.;
2. Method according to the preceding claim, in which the diisocyanate compound blocked in the aqueous adhesive composition of the second bath is at a mass rate 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% and even more preferably less than or equal to 0.05%.
3. A method according to any preceding claim, wherein the epoxy compound is selected from the group consisting of 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; pentaerythrithiol, polyglycidyl ether, diglycerol, polyglycidyl ether; sorbitol polyglycidyl ether or isosorbide diglycidyl ether and preference is polyglycerol polyglycidyl ether.
4. A method according to any preceding claim, wherein the blocked diisocyanate compound is selected from the group consisting of diphenylmethane diisocyanates and polyphenylene polymethylene polyisocyanates and preferably is N,N'-(methylenedi-p-phenylene)bis [hexahydro-2-oxo-1 H-azepine-1 -carboxamide] 4,4'-diisocyanate.
5. A method according to any one of claims 1 to 4, wherein the compound Al is formaldehyde.
6. Method according to any one of claims 1 to 4, in which the compound Al comprises at least one aromatic nucleus carrying at least one aldehyde function.
7. Method according to the preceding claim, in which the compound Al carries at least two aldehyde functions.
8. The method of claim 6, wherein compound A1 is selected from the group consisting of 1,2-benzene-dicarboxaldehyde, 1,3-benzene-dicarboxaldehyde, 1,4-benzene-dicarboxaldehyde, 2-hydroxybenzene-1,3,5-tricarbaldehyde and mixtures of these compounds.
9. Process according to any one of the preceding claims in which the phenol A21 is chosen from: - an aromatic polyphenol A2 comprising at least one aromatic ring carrying at least two hydroxyl functions in meta position relative to each other, the two ortho positions of at least one of the hydroxyl functions being unsubstituted; - an aromatic monophenol A2' comprising at least one six-membered aromatic ring carrying a single hydroxyl function, with: - the two ortho positions of the hydroxyl function being unsubstituted or; - at least one ortho position and the para position of the hydroxyl function being unsubstituted; - a mixture of A2 and A2'.
10. A method according to the preceding claim, wherein the aromatic polyphenol A2 is selected from the group consisting of resorcinol, phloroglucinol, 2,2',4,4'-tetrahydroxydiphenyl sulfide, 2,2',4,4'-tetrahydroxybenzophenone and mixtures of these compounds and preferably is phloroglucinol.
11. Method according to any one of the preceding claims in which a step of drying the CVR composite is carried out following step a) of pre-adhesion of the CVR composite by drying at a temperature greater than or equal to 120°C for at least 5 seconds then by heat treatment at a temperature greater than or equal to 180°C for at least 5 seconds.
12. Method according to any one of the preceding claims in which a step of drying the CVR composite is carried out following step b) of deposition on the CVR composite by drying at a temperature greater than or equal to 120°C for at least 5 seconds then by heat treatment at a temperature greater than or equal to 180°C for at least 5 seconds.
13. Elastomer composite reinforced with at least one or more strands of glued CVR Glass-Resin composite embedded in an elastomer matrix, characterized in that the glued CVR Glass-Resin composite strand(s) are obtained by the method according to any one of claims 1 to 12.
14. Tire (1), characterized in that it comprises an elastomer composite according to claim 13.
15. Belt (P), characterized in that it comprises an elastomer composite according to claim 13.