WO2016051028A1 - Sulphur-containing aromatic polyol compound - Google Patents

Abstract

The invention relates to a sulphur-containing polyol compound that can be used in particular as a monomer for the synthesis of a polyurethane by polycondensation with a polyisocyanate, having formula (I): HO - CH₂ - (Z₁)a - CH(OH) - CH₂ - S - Z₃ - S - CH₂ - CH(OH) - (Z₂)b - CH₂ - OH, in which: Z₁ and Z₂, identical or different, represent an optional at-least-divalent linking group comprising at least one carbon atom; a and b, identical or different, are equal to 0 or 1; and Z₃ represents an at-least-divalent aromatic linking group comprising at least six carbon atoms, each sulphur atom on each side of the Z₃ group being connected directly to a Z₃ aromatic ring.

Description

 SOFT AROMATIC POLYOL COMPOUND

1. DOMAIN OF THE INVENTION

The present invention relates to the monomers that can be used for the synthesis of polymers with urethane units (or polyurethanes) especially for adhesive systems for bonding glass or metal to rubber.

It relates more particularly to the above monomers of the sulfur polyol type, in particular for the synthesis of polyurethanes used in metal / rubber type composites for rubber articles such as tires.

2. STATE OF THE ART

Composites of the metal / rubber type, in particular for tires, are well known. They generally consist of an unsaturated rubber matrix, generally diene, crosslinkable with sulfur, comprising reinforcing elements (or "reinforcements") of metal such as carbon steel wires, films or cables.

Subject to very significant constraints during the rolling of the tires, in particular to repeated compressions, flexions or curvature variations, these composites must in a known manner satisfy a large number of technical criteria, sometimes contradictory, such as uniformity, flexibility, endurance in flexion and compression, tensile, wear and corrosion resistance, and maintain these performances at a very high level as long as possible.

It is easy to understand that the adhesive interphase between rubber and reinforcements plays a preponderant role in the durability of these performances. The traditional method of bonding the rubber compositions to carbon steel is to coat the surface of the steel with brass (copper-zinc alloy), the bond between the steel and the rubber matrix being provided by sulfurization brass when vulcanizing or baking rubber. To improve adhesion, organic rubber or metal complexes such as cobalt salts, as adhesion promoting additives, are generally also used in these rubber compositions. However, it is known that the adhesion between the carbon steel and the rubber matrix is likely to weaken over time, due to the progressive evolution of the sulphides formed under the effect of the various stresses encountered, in particular mechanical and / or thermal, the above degradation process can be accelerated in the presence of moisture.

On the other hand, the use of cobalt salts renders the rubber compositions more susceptible to oxidation and aging, and significantly increases their cost, not to mention the fact that it is desirable to eventually eliminate the use of such compounds. Cobalt salts in rubber compositions, due to the recent evolution of European regulations on this type of metal salts.

For all the above reasons, manufacturers of metal / rubber composites, in particular tire manufacturers, are looking for new adhesive solutions for bonding metal reinforcements to rubber compositions, while at the same time compensating for part, the aforementioned disadvantages.

3. BRIEF DESCRIPTION OF THE INVENTION

However, in the course of their research, the Applicants have found a new polyol compound, aromatic sulfur type, which allows the synthesis of a polyurethane meeting such an objective.

According to the invention, said sulfurized aromatic polyol compound corresponds to the following formula (I): HO - CH ₂ - (Z 1) _a - CH (OH) - CH ₂ --S - Z ₃ - S - CH ₂ - CH (OH) - (Z ₂ ) _b - CH ₂ - OH in which:

Z ₁ and Z ₂ , which may be identical or different, represent an optional linking group, at least divalent, comprising at least one carbon atom;

 a and b, identical or different, are 0 or 1;

Z ₃ represents an at least divalent aromatic linking group comprising at least 6 carbon atoms, each sulfur atom on either side of the Z ₃ group being directly attached to an aromatic ring of Z ₃ .

Thanks to this very specific sulfur-containing aromatic polyol (primary diol) compound, comprising in particular, in addition to its two primary alcohol functions, at least two secondary alcohol functions and, on the other hand, a thioether (- S -) function in position. alpha of each of these two secondary alcohol functions, it has proved possible to prepare a polyurethane which, used as an adhesion primer on metal reinforcements, gives these reinforcements the major and unexpected advantage of being able to adhere to unsaturated rubber matrices by using simple textile glues such as "RFL" glues (resorcinol-formaldehyde). latex) or other equivalent adhesive compositions, or directly (that is to say without using such glues) to these unsaturated rubber matrices when the latter contain for example suitable functionalized unsaturated elastomers such as for example epoxidized elastomers.

The invention also relates to the use of a polyol compound according to the invention for the manufacture of a polyurethane, as well as any polyurethane derived from at least one polyol compound according to the invention.

The invention also relates to any process for synthesizing a polyurethane by polycondensation of at least one polyol compound according to the invention with a polyisocyanate compound.

The invention as well as its advantages will be readily understood in the light of the detailed description and the following exemplary embodiments, as well as FIGS. 1 to 3 relating to these examples which represent or schematize: two examples of sulfur-containing polyol compounds conforming to the the invention (denoted as M1 and M2 monomers), as well as a synthetic scheme that can be used to obtain each of these compounds (Figure 1 and Figure 2);

 a detailed synthetic scheme usable from the Monomer M1 according to the invention and a diisocyanate monomer (Monomer A2, MDI blocked benzophenone), a polyurethane polymer PI according to the invention (Figure 3).

4. DETAILED DESCRIPTION OF THE INVENTION

It will first be recalled here that a polyurethane is a polymer (by definition any homopolymer or copolymer, especially a block copolymer) comprising a plurality of urethane bonds (-O-CO-NH-) resulting in a known manner from the reaction of addition of a polyol having at least two primary alcohol functional groups to a polyisocyanate (compound carrying at least two isocyanate functional groups -NCO), in particular to a diisocyanate in the case of a polyurethane of the linear type.

The aromatic polyol (primary diol) sulfur compound of the invention, especially usable for the synthesis of a polyurethane, therefore corresponds to formula (I): HO - CH ₂ - (Z 1) _a - CH (OH) - CH ₂ --S - Z ₃ --S - CH ₂ --CH (OH) - (Z ₂ ) _b --CH ₂ --OH in which:

Z ₁ and Z ₂ , which are identical or different, represent an optional linking group, at least divalent, comprising at least 1 carbon atom;

et Z₂ peuvent être présents ou pas) ; a and b, the same or different, are 0 or 1 (i.e.

and Z ₂ may be present or not);

Z ₃ represents an at least divalent aromatic linking group comprising at least 6 carbon atoms, each sulfur atom on either side of the Z ₃ group being directly attached to an aromatic ring of Z ₃ .

This sulfur-containing aromatic polyol compound therefore has, in particular, the essential characteristic of comprising, on either side of the aromatic central group - Z ₃ -, a secondary alcohol function (- CH (OH) -) and a thioether function (- S -). in position a (alpha, that is to say for recall and by convention, carried by a carbon adjacent to the carbon carrying the secondary alcohol function) of this secondary alcohol function. In other words, this polyol compound comprises an α-hydroxy-thioether unit on either side of the Z ₃ group.

Z ₁ , Z ₂ and Z ₃ are linking groups, spacing units, of organic type, preferably hydrocarbon, also commonly called "separators" or "spacers" (in English spacers) by the skilled person; they can be saturated or unsaturated.

et Z₂, identiques ou différents, substitués ou non substitués, représentent un groupement de liaison aliphatique ayant 1 à 20 atomes, plus préférentiellement 1 à 12 atomes de carbone, ou cycloaliphatique ayant 3 à 20 atomes de carbone, plus préférentiellement 3 à 12 atomes de carbone ; plus particulièrement, il s'agit d'un alkylène en Ci-Cio, notamment en C₁-C5. According to a particular embodiment,

and Z ₂ , identical or different, substituted or unsubstituted, represent an aliphatic linking group having 1 to 20 atoms, more preferably 1 to 12 carbon atoms, or cycloaliphatic having 3 to 20 carbon atoms, more preferably 3 to 12 atoms of carbon ; more particularly, it is a C ₁ -C ₁₀ alkylene, especially C ₁ -C ₅ alkylene.

According to another preferred embodiment, Z ₃ comprises 6 to 30, more preferably 6 to 20 carbon atoms. By definition, each sulfur atom on either side of Z ₃ is directly connected to an aromatic nucleus, it being understood that the latter may be the same nucleus or a different nucleus for these two sulfur atoms. Even more preferably, Z ₃ comprises at least one (in particular one or two) phenylene group, this last group (s) may be substituted or unsubstituted.

According to another preferred embodiment, at least one of the groups Z _ls Z ₂ and Z ₃ comprises at least one (that is to say 1 or more) heteroatom preferably selected from O, S or N. According to another preferred embodiment, at least one of the groups Z _ls Z ₂ and Z ₃ comprises at least one (that is to say 1 or more) ether bond (- O -) or thioether (- S -), the latter may be present on the carbon chain (Z _ls Z ₂ or Z ₃ ) itself or on a substituent of one of its carbon atoms.

According to a preferred embodiment, a and b are equal to zero; in other words, in such a case, the primary sulfur-containing diol compound of the invention has the formula (F):

()

HO - CH ₂ - CH (OH) - CH ₂ - S - Z ₃ - S - CH ₂ - CH (OH) - CH ₂ - OH

The formulas below (with "n" integer ranging for example from 1 to 30, in particular from 1 to 20, more particularly from 1 to 10) illustrate, by way of examples, different groups corresponding to the definition of the sequence. - S - Z ₃ - S - above:

 FIGS. 1 and 2 show, in developed form, the formulas of two examples of sulfur-containing aromatic polyol compounds according to the invention, labeled M1 and M2 monomers, as well as a synthetic scheme that can be used for obtaining of each of these compounds.

The polyol compound (Monomer M1, also later referred to as Al Monomer) of Figure 1 is 3- {4- [4- (2,3-dihydroxy-propylsulfanyl) -phenylsulfanyl] -phenylsulfanyl} -propane-1,2 diol. It can be obtained for example by reaction of 4,4'-thiobisbenzenethiol and liquid 3-chloro-1,2-propanediol, as shown diagrammatically in FIG. 1. Its synthesis will be described in more detail in the following embodiments ( Test 1 of paragraph 5.1).

The polyol compound (Monomer M2) of Figure 2 is 3- (4- {4- [4- (2,3-dihydroxypropylsulfanyl) -phenyl] -6-phenyl- [1,3,5] triazin- 2-yl} -phenylsulfanyl) propane-1,2-diol.

It can be obtained for example according to the process shown diagrammatically in FIG.

Under a stream of nitrogen, 4 flasks of 500 ml (equipped with a condenser, a magnetic bar and a nitrogen inlet, previously dried under vacuum at a temperature above 100 ° C.) are introduced into a flask. 5.70 g (or 16.5 mmol) of 2,4-bis- (p-fluorophenyl) - [1,3,5] -s-triazine, 200 ml of anhydrous DMSO solvent, followed by dry potassium carbonate. (6.03 g, 43.6 mmol); previously, the triazine compound and the potassium carbonate were both dried under vacuum at 150 ° C overnight. The starting triazine compound was synthesized in a known manner, as taught in application WO 2012/016777 (Test V-1-A, Compound 1, Fig. 18). The system is then purged for 30 minutes with stirring under a stream of nitrogen. Then introduced 4.29 g (ie 39.6 mmol) of 1-thioglycerol and the suspension is heated at 100 ° C for 4.5 h under a stream of nitrogen and stirring. The reaction mixture is then cooled to room temperature (23 ° C) and the potassium carbonate is filtered off on filter paper; the salt is washed with an additional 50 ml of DMSO. The filtrate is then poured into 250 ml of ice water and thus precipitated. 100 ml of HCl solution (10%) and 1 liter of demineralized water are then added; the pH is adjusted to 1.0 using the HC1 solution (10%). The white precipitate (Monomer M2) thus obtained (8.6 g, yield of about 100%) is isolated by filtration on filter paper, washed with deionized water and dried overnight at 90 ° C. under vacuum. The common characteristic of the two aromatic sulfur-containing polyol compounds previously described in FIGS. 1 and 2 is that they all correspond to the formula (Γ):

HO - CH ₂ - CH (OH) - CH ₂ --S - Z ₃ --S - CH ₂ --CH (OH) - CH ₂ --OH in which, for these examples: a and b are 0, d other terms Z ₁ and Z ₂ are absent;

Z ₃ represents a divalent aromatic linking group comprising at least 6 carbon atoms and furthermore at least one heteroatom (S or N), each sulfur atom on either side of the Z ₃ group being connected directly to an aromatic nucleus (phenylene group).

The sulfur-containing aromatic polyol compound according to the invention described above is preferably used for the synthesis of a polyurethane of the linear type, thus resulting essentially from the addition of this polyol (primary diol) and a diisocyanate compound. The usable diisocyanate may be aromatic, aliphatic or cycloaliphatic; it may be a monomer, a prepolymer or quasi-prepolymer, or even a polymer.

According to a preferred embodiment, the diisocyanate from which the polymer of the invention is derived is selected from the group consisting of the following aromatic compounds: diphenylmethane diisocyanate (abbreviated "MDI"), toluene diisocyanate ("TDI"), naphthalene diisocyanate ("NDI"), 3,3'-benzenediis diisocyanate ("TODI"), para-phenylene diisocyanate ("PPDI"), their various isomers, and mixtures of these compounds and / or isomers.

More preferably, an MDI or a TDI is used, more preferably still an MDI.

Sont également utilisables des composés diisocyanates du type aliphatiques, tels que par exemple 1 ,4-tétraméthylène diisocyanate, 1,6-hexane-diisocyanate (« HDI »), 1,4- bis(isocyanatométhyl)-cyclohexane, 1 ,3-bis(isocyanatométhyl)-cyclohexane, 1,3- bis(isocyanatométhyl)benzène, l,4-bis(isocyanatométhyl)benzène, isophorone diisocyanate (« IPDI »), bis(4-iso-cyanatocyclohexyl)méthane diisocyanate (« H12MDI »), 4,4'- dicyclohexylméthane diisocyanate (« H13MDI »). All isomers of MDI (in particular 2,2'-MDI, 2,4'-MDI, 4,4'-MDI) and their mixtures are usable, as well as so-called polymeric MDIs (or "PMDI") comprising oligo-mothers. of the following formula (with p equal to or greater than 1):

Also suitable are aliphatic diisocyanate compounds, such as, for example, 1,4-tetramethylene diisocyanate, 1,6-hexane diisocyanate ("HDI"), 1,4-bis (isocyanatomethyl) -cyclohexane, 1,3-bis (isocyanatomethyl) -cyclohexane, 1,3-bis (isocyanatomethyl) benzene, 1,4-bis (isocyanatomethyl) benzene, isophorone diisocyanate ("IPDI"), bis (4-iso-cyanatocyclohexyl) methane diisocyanate ("H12MDI"), 4,4'-dicyclohexylmethane diisocyanate ("H13MDI").

ou, si plusieurs diisocyanates sont utilisés, constitue le diisocyanate majoritaire en poids, représentant de préférence dans le dernier cas plus de 50% du poids total des composés diisocyanates. According to a particularly preferred embodiment, the diisocyanate used is 4,4'-MDI (4,4'-diphenylmethane diisocyanate) having the formula:

or, if several diisocyanates are used, is the majority diisocyanate by weight, preferably representing in the latter case more than 50% of the total weight of the diisocyanate compounds.

It is also possible to advantageously use a blocked 4,4'-MDI caprolactam (for example the product in solid form "Grilbond" IL-6 from the company EMS), of formula:

 The invention is not however limited to a polymer of the linear type (as a reminder, derived from a diisocyanate), it may also be used, in particular with the aim of increasing the Tg of the polymer of the invention by formation of a three-dimensional network, a triisocyanate compound such as, for example, a triazine ring MDI trimer of formula below:

Le polyuréthane issu du composé polyol de l'invention a donc pour caractéristique de comporter, outre ses unités structurelles de base à unités uréthane (-0-CO-NH-) apportées de manière bien connue par le composé de départ polyisocyanate, des unités additionnelles récurrentes spécifiques apportées par le monomère polyol selon l'invention, ces unités additionnelles comportant au moins un motif de formule (II) :

The polyurethane resulting from the polyol compound of the invention therefore has, in addition to its urethane unit (-O-CO-NH-) basic structural units made in a manner well known to the polyisocyanate starting compound, additional units. specific recurring provided by the polyol monomer according to the invention, these additional units comprising at least one unit of formula (II):

(H)

- O - CH ₂ - (Z) _a - CH (OH) - CH ₂ - S - Z ₃ - S - CH ₂ - CH (OH) - (Z _{2) b} - CH ₂ - wherein Z _ls Z _2, Z ₃ , a and b have of course the main and preferential definitions given above.

The formula (III) below reproduces an exemplary sequence (repeating structural unit) of polyurethane type polymers, this sequence comprising on the one hand a base unit (urethane) provided by a diisocyanate (here, of formula OCN-Z -NCO), and on the other hand an additional unit provided by a polyol compound according to the invention, namely:

(III)

-O-C (O) -NH-Z-NH-C (O) -O-CH ₂ - (Z ₁ ) _a -CH (OH) -CH ₂ -SZ ₃ -S-CH ₂ -CH (OH) - (Z ₂ ) _b -CH ₂ -

In formula (III) above, Z represents an at least divalent, saturated or unsaturated linking group; it is preferably an aliphatic, cycloaliphatic or aromatic group, the aliphatic group preferably comprising 1 to 30 (more preferably 1 to 20) carbon atoms, the cycloaliphatic group preferably comprising from 3 to 30 (more preferably 3 at 20) carbon atoms, the aromatic group, substituted or unsubstituted, preferably containing from 6 to 30 (more preferably 6 to 20) carbon atoms.

FIG. 3 illustrates a possible synthesis process, from the polyol monomer according to the invention (M monomer, also noted as A1) and another monomer (Monomère A2), of a polymer according to the invention of the type polyurethane (Polymer P1), a process which will be described in detail later.

This example of Polymer P1 prepared according to the invention does indeed comprise a repeating unit of formula (III) in which Z corresponds more particularly to the divalent residue group of MDI, a and b are equal to 0 and Z ₃ represents an aromatic group carrying, in particular, a thioether bond (- S -). FIG. 3 clearly shows that, according to the invention, the polymer P1 comprises, in addition to its urethane base units, additional units which comprise two α-hydroxy-thioether functions (-CH (OH) -CH ₂ -S -) on both sides of Z ₃ .

The polyurethane synthesizable from a sulfur-containing aromatic polyol compound according to the invention may comprise from ten to several hundred, preferably from 20 to 200 recurring structural units as described above. Its glass transition temperature Tg, measured by DSC (Differential Scanning Calorimetry), for example according to the ASTM D3418 standard, is preferably greater than 50 ° C., more preferably greater than 100 ° C., in particular between 130 ° C. and 250 ° C. ° C.

This polyurethane has a high flexibility, a significant elongation at break, it has also revealed hydrophobic properties and effective anti-corrosion properties.

It is advantageously usable as a hydrophobic coating on any type of substrate, especially metal or glass, or as adhesion primer on any type of metal reinforcement, such as for example a wire, a film, a plate or a cable. carbon steel, brass or non-brass, in particular for reinforcing an unsaturated rubber matrix such as natural rubber.

5. EXAMPLES OF CARRYING OUT THE INVENTION

In the present application, unless expressly indicated otherwise, all the percentages (%) indicated are percentages by mass.

5.1. Test 1 - Synthesis of Al Monomer

The monomer Al (or M1) is 3- {4- [4- (2,3-dihydroxy-propylsulfanyl) -phenylsulfanyl] phenylsulfanyl} -propane-1,2-diol according to the invention. This monomer was synthesized according to the procedure schematized in FIG. 3, as detailed below.

In a 500 ml 4-neck flask previously dried under vacuum at more than 100 ° C., equipped with a condenser, thermometer and magnetic bar, 8.3 g of (Compound) are introduced under an inert atmosphere (stream of nitrogen). 1) 4,4'-thiobisbenzenethiol solid (ie 33.03 mmol) then 10.0 g of potassium carbonate (ie 72.56 mmol, previously dried under vacuum at 150 ° C for 12 h). 200 ml of anhydrous DMSO are then poured in, the dispersion is purged under nitrogen for 30 minutes, then 7.29 g of liquid (2-chloro-1,2-propanediol (66.06 mmol) are added dropwise. ). The reaction mixture is heated immediately at 100 ° C. for 5 h, still under a nitrogen current. The solution obtained is then allowed to cool at room temperature, and the solid potassium carbonate (K ₂ CO ₃ ) is recovered by filtering on a filter paper. The filtrate is then washed with 50 ml of DMSO and then poured into 250 ml of deionized water at 0 ° C. (ice) to precipitate the desired product.

To neutralize residual K ₂ CO ₃ , 10 ml of HCl (10%) and 1 liter of deionized water are then added. After drying under vacuum at 60 ° C. overnight (12 h), the precipitate obtained (orange sticky solid) is poured into 500 ml of ethyl acetate, the whole heated up to 40 ° C. to complete dissolution. The solution obtained is cooled to room temperature (20 ° C.) and then transferred to a separation funnel, 50 ml of saturated (aqueous) NH ₄ CI are then added. After stirring, the organic phase is separated and then washed twice with 25 ml of deionized water, and then dried with dry sodium carbonate. After filtration and distillation of the ethyl acetate on a rotary evaporator ("Rotavap"), the solid obtained is dried at 80 ° C.

The NMR and ESI analyzes confirm the structure of the Al monomer, of formula:

1 H NMR analysis (500 MHz, DMSO- ¾) of the product gave the following results:

 2.89 (m, 2H), 3.11 (m, 2H), 3.40 (m, 4H), 3.61 (m, 2H), 4.67 (d, 2H), 4.99 (d, 2H), 7.22-7.24 (d, 4H). 7.31-7.33 (d, 4H).

As for the molecular mass measured by mass spectrometry ESI, in a mixture ethyl acetate / methanol (1/1) (with traces of aqueous NaCl), it was evaluated in negative mode (anion [M + C1] ^~ ) at 433.3 (calculated theoretical value equal to 434.0), and in positive mode (cation [M + Na] ⁺ ) at 421.1 (theoretical value calculated equal to 420.6).

5.2. Test 2 - Synthesis of Polymer PI by reaction of Al and A2 monomers

This test describes in detail the synthesis of the Polymer P1 according to the invention, starting from the monomers A1 and A2 (blocked MDI caprolactam), according to the procedure shown diagrammatically in FIG.

280.0 mg of Monomer Al, 334.6 mg of Monomer A2 ("Grilbond" IL-6) and 8 ml of NMP solvent are placed in a glass vial. The suspension is heated (under a stream of hot air) to 120 ° C until a clear solution is obtained. Then 3 ml of the solution thus obtained is deposited on a polished brass plate (10 × 10 cm ² ) which is then passed to the oven at 190 ° C. for 15 minutes. A transparent film of Polymer PI is thus obtained, the analysis of which DSC (second pass, -80 ° C to 200 ° C, 10 ° C / min) revealed a Tg of about 115 ° C. It may be noted that a similar polymerization reaction, but conducted in a solvent mixture 1-methoxypropanol-2-acetate / sulfolane (3: 1), resulted in a Tg of about 130 ° C.

5.3. Test 3 - Polymer 1 Adhesion Test in a Metal / Rubber Composite

A thin film of the thus obtained Polymer PI was deposited (at room temperature) uniformly on the surface of a brass plate. Then we covered the whole with a layer of conventional textile glue type "RFL" (resorcinol-formaldehyde-latex). After pre-drying for 5 min at 100 ° C., the whole was then treated in an oven at 190 ° C. for 10 min.

The brass plate thus coated with the Polymer film PI and glued with RFL, was then placed in a composition matrix (raw, unvulcanized) of conventional rubber for touring tire belt reinforcement, based on natural rubber. , carbon black and silica as a filler, and a vulcanization system (sulfur and sulfenamide accelerator); this composition being free of cobalt salt.

Then the metal / rubber composite specimen thus prepared was placed in a press and baked (vulcanized) at 165 ° C for 30 min at a pressure of 20 bar. After vulcanization of the rubber, excellent bonding was obtained between the rubber matrix and the metal plate despite the absence of cobalt salt in the rubber matrix: in peel tests conducted at both room temperature (23 ° C.). C) and at high temperature (100 ° C.), it has indeed been found that the rupture occurs systematically in the rubber matrix itself and not in the interphase between metal and rubber.

In conclusion, the aromatic sulfur polyol compounds of the invention make it possible to synthesize polyurethanes which are characterized by a high glass transition temperature, a high thermal and chemical stability, and an excellent adhesion to glass or metal.

Thanks to the invention, these polyurethanes, used as adhesion primer on metal in metal / rubber composites, very advantageously allow then to stick the metal to the rubber matrices using for example simple textile glues such as "RFL" glues Resorcinol-formaldehyde-latex) or other equivalent adhesive compositions, or directly (i.e., without use of such glues) to these rubber matrices where the latter contain, for example, suitable functionalized unsaturated elastomers such as epoxidized elastomers.

Thus, cobalt salts (or other metal salts) may in particular be omitted in rubber compositions intended to be connected to brass-coated metal reinforcements.

Claims

1. aromatic sulfur polyol compound, usable especially as a monomer for the synthesis of a polyurethane by polycondensation with a polyisocyanate, said polyol compound corresponding to the formula:  (I) HO - CH ₂ - (Z 1) _a - CH (OH) - CH ₂ --S - Z ₃ --S - CH ₂ --CH (OH) - (Z ₂ ) _b --CH ₂ --OH in which: Z ₁ and Z ₂ , which may be identical or different, represent an optional linking group, at least divalent, comprising at least one carbon atom;  a and b, identical or different, are 0 or 1; Z ₃ represents an at least divalent aromatic linking group comprising at least 6 carbon atoms, each sulfur atom on either side of the Z ₃ group being directly attached to an aromatic ring of Z ₃ . 2. Compound according to claim 1, wherein Zi and Z ₂ , which are identical or different, represent an aliphatic group comprising 1 to 20, preferably 1 to 12 carbon atoms, or a cycloaliphatic group comprising 3 to 20, preferably 3 to 12 carbon atoms. 3. Compound according to claim 2, wherein Zi and Z ₂ , which may be identical or different, represent a C ₁ -C ₁₀ , preferably C ₁ -C _5, alkylene group. 4. Compound according to any one of claims 1 to 3, wherein Z ₃ represents an aromatic group having 6 to 30, preferably 6 to 20 carbon atoms. 5. A compound according to any one of claims 1 to 4, wherein at least one of groups Z _ls Z ₂ and Z ₃ contains a heteroatom selected from O, S or N. 6. A compound according to claim 5, wherein at least one of groups Z _ls Z ₂ and Z ₃ contains an ether bond or thioether. A compound according to any one of claims 1 to 6, wherein a and b are O. 8. A compound according to claim 7, having the formula:

9. A compound according to claim 7, having the formula:

 10. Urethane unit polymer derived from at least one aromatic sulfur polyol compound according to any one of claims 1 to 9, said polymer comprising at least units comprising a unit of formula: (H) - O - CH ₂ - (Z 1) _a - CH (OH) - CH ₂ - S - Z ₃ - S - CH ₂ - CH (OH) - (Z ₂ ) _b - CH ₂ - 11. A process for synthesizing a urethane-functional polymer by polycondensation of at least one sulfur-containing aromatic polyol compound according to any one of claims 1 to 9 with a polyisocyanate compound. Use of a sulfur aromatic polyol compound according to any one of claims 1 to 9 for the manufacture of a urethane-functional polymer.