Aqueous impregnation composition

Abstract

The present invention relates to an aqueous impregnation composition for coating a textile reinforcement material, comprising 4% to 40% by dry weight of at least one rubber latex, provided that the rubber latex is not an isoprene rubber latex, 0.1% to 10% by dry weight of at least one blocked isocyanate, 1% to 20% by dry weight of at least one isoprene rubber latex, and 0% to 6% by dry weight of at least one epoxy-containing compound, wherein the amounts in dry weight % are based on the total weight of the aqueous impregnation composition, and wherein the composition is substantially free of resorcinol, resorcinol precondensates, formaldehyde and substances that release formaldehyde. The present invention further relates to the use of such a composition, a method for coating a textile reinforcement material with such a composition, a coated textile reinforcement material and respective elastomeric articles comprising a coated textile reinforcement material.

Description

[0001] The present invention relates to an aqueous impregnation composition for coating a textile reinforcement material, comprising 4% to 40% by dry weight of at least one rubber latex, provided that the rubber latex is not an isoprene rubber latex, 0.1% to 10% by dry weight of at least one blocked isocyanate, 1% to 20% by dry weight of at least one isoprene rubber latex, and 0% to 6% by dry weight of at least one epoxy-containing compound, wherein the amounts in dry weight % are based on the total weight of the aqueous impregnation composition, and wherein the composition is substantially free of resorcinol, resorcinol precondensates, formaldehyde and substances that release formaldehyde. The present invention further relates to the use of such a composition, a method for coating a textile reinforcement material with such a composition, a coated textile reinforcement material and respective elastomeric articles comprising a coated textile reinforcement material.

[0002] It is known that various components of motor vehicle tires include textile reinforcements (hereinafter also referred to as textile reinforcement materials) for reinforcement. These textile reinforcements are usually based on multifilament textile cords or flat structures such as tapes, which are also based on multifilament yarns. Other industrial elastomeric products, such as belts and hoses, may also include such reinforcements. In tires or other industrial elastomeric products, reinforcements are usually provided together with elastomeric compounds or rubber mixtures. One problem is that reinforcements and elastomeric compounds usually have different strengths. Especially under continuous mechanical stress and dynamic stress, such as in the driving operation of motor vehicle tires, sufficient bonding between reinforcements and surrounding elastomeric compounds is therefore necessary.

[0003] For adequate bonding, activation of the reinforcement (activation of bonding) prior to gluing is known in the prior art. This is usually achieved by treating the reinforcement with an impregnation composition that promotes subsequent bonding between the reinforcement and the elastomeric compound. Such an impregnation composition must meet various requirements. Most importantly, the impregnation composition must provide activation of the reinforcement to enable good bonding between the reinforcement and the elastomeric compound. The reinforcement treated with the impregnation composition should also provide good storage stability (hereinafter also referred to as shelf life stability) so that the treated reinforcement does not have to be further processed immediately. Finally, the impregnation composition should be easy to handle and can be processed well.

[0004] Traditionally, impregnation compositions containing RFL (resorcinol-formaldehyde latex) have been used for this purpose, and the reinforcement has been treated with such a composition before being bonded to the elastomeric compound. Furthermore, it is known to use blocked isocyanates and / or epoxy compounds in combination with RFL dips to pre-activate or further activate the reinforcement. WO 2005 / 026239 A1, for example, discloses the use of polyisocyanates and RFL.

[0005] However, resorcinol and formaldehyde are classified as harmful to the environment and health, and efforts have been made to provide alternatives thereto. RF-free impregnation compositions have been proposed, as described, for example, in WO 2015 / 188939 A1, WO 2014 / 175844 A2 and WO 2014 / 091376 A1. These compositions are based on acrylic polymer resins, epoxy resins, blocked polyisocyanates and styrene-butadiene (SBR) latex and / or vinyl-pyridine (VP) latex, and the cords treated with these compositions show good bonding to the rubberizing mixture. However, these patent applications do not mention the storage stability of the textile reinforcements treated with the compositions. Another RF-free impregnation composition is described in CN 106084362. This composition consists of blocked isocyanates, epoxy compounds, rubber latex, rubber modifiers and water. However, it is not entirely clear from the patent application what the recommended weight ratios of the various components are. Furthermore, the patent application also does not mention the storage stability of the textile reinforcements treated with the compositions.

[0006] In view of the above, it is an object of the present invention to provide an RF-free impregnation composition for coating textile reinforcements which provides a further improved bond between reinforcement and elastomeric compound while being easy to handle and allowing long term storage of the treated textile reinforcements.

[0007] This technical problem is solved by the embodiments characterized in the claims.

[0008] In particular, the present invention provides an aqueous impregnation composition for coating a textile reinforcement material, comprising 4 to 40 wt % (dry weight) of at least one rubber latex, provided that the rubber latex is not isoprene rubber latex, 0.1 to 10 wt % (dry weight) of at least one blocked isocyanate, 1 to 20 wt % (dry weight) of at least one isoprene rubber latex, and 0 to 6 wt % (dry weight) of at least one epoxy-containing compound, wherein the amounts in wt % are based on the total weight of the aqueous impregnation composition, and wherein the composition is substantially free of resorcinol, resorcinol precondensate, formaldehyde and formaldehyde-releasing substances.

[0009] It is pointed out that the expression "% by weight (dry weight)" used in the present description is equivalent to and synonymous with "% by dry weight". This term is used to expressly indicate the dry weight of the respective component (and not, for example, the weight of the aqueous dispersion of the component). When within the present description it is indicated that the amounts in % by weight are based on the total weight of the aqueous impregnation composition, this again means that the amounts in % by dry weight are based on the total weight of the aqueous impregnation composition.

[0010] The present invention provides RF-free aqueous impregnation compositions that can be used to coat textile reinforcement materials. The specific combination of components of the claimed aqueous impregnation composition enables a number of chemical reactions to occur, whereby the textile reinforcement material is activated, which results in a further improved bonding between the textile reinforcement material and the elastomeric compound compared to the impregnation compositions of the prior art. Furthermore, it has surprisingly been found that the storage stability of textile reinforcement materials treated with the claimed composition is improved compared to the RF-free impregnation compositions of the prior art. Furthermore, the aqueous impregnation composition according to the invention is easy to handle and can be used for a wide variety of textile reinforcement materials.

[0011] According to the present invention, the rubber latex may be any suitable rubber latex, provided that it is not isoprene rubber latex. For example, the at least one rubber latex can be selected from styrene-butadiene rubber latex (SBR), ethylene-propylene-diene rubber latex (EPDM), butyl rubber latex (IIR), styrene-butadiene-vinyl pyridine rubber latex (VP), nitrile rubber latex (NBR), chloroprene rubber latex (CR), butadiene rubber latex (BR), ethylene-vinyl acetate rubber latex (EVM), hydrogenated nitrile rubber latex (HNBR), polyacrylate rubber latex (ACM), chloropolyethylene rubber latex (CM), chlorosulfonated polyethylene rubber latex (CSM), ethylene-propylene rubber latex (EPM), fluororubber latex (FKM), epichlorohydrin rubber latex (CO), epichlorohydrin copolymer rubber latex (ECO), propylene oxide copolymer rubber latex (GPO), bromobutyl rubber latex (BIIR), chlorobutyl rubber latex (CIIR), silicone rubber latex, functionalized rubber latex or a combination thereof. According to a preferred embodiment, the at least one rubber latex is selected from styrene-butadiene rubber latex (SBR), ethylene-propylene-diene rubber latex (EPDM), butyl rubber latex (IIR), styrene-butadiene-vinyl pyridine rubber latex (VP), nitrile rubber latex (NBR), chloroprene rubber latex (CR), butadiene rubber latex (BR), functionalized rubber latex and combinations thereof. The functionalization may be any suitable functionalization except carboxylation. According to a particularly preferred embodiment of the present invention, the rubber latex is selected from styrene-butadiene-vinyl pyridine rubber latex (VP), styrene-butadiene rubber latex (SBR) and combinations thereof.

[0012] The styrene-butadiene-vinyl pyridine rubber latex (VP) may be any suitable styrene-butadiene-vinyl pyridine rubber latex. A preferred example of the styrene-butadiene-vinyl pyridine rubber latex is a latex comprising 10-20% vinyl pyridine, 10-20% styrene and 60-80% butadiene monomers. Preferably, the butadiene component is selected from 1,3-butadiene and 2-methyl-1,3-butadiene. The styrene component is preferably selected from styrene, α-methyl styrene, 2-methyl styrene, 3-methyl styrene, 4-methyl styrene, 2,4-diisopropyl styrene, 2,4-dimethyl styrene, 4-tert-butyl styrene and hydroxymethyl styrene. The vinyl pyridine monomer is preferably selected from 2-vinyl pyridine, 3-vinyl pyridine, 4-vinyl pyridine, 2-methyl-5-vinyl pyridine and 5-ethyl-2-vinyl pyridine.

[0013] According to a particularly preferred embodiment of the present invention, the rubber latex of the claimed aqueous dipping composition is a mixture of various latexes. For example, the rubber latex may comprise styrene-butadiene-vinyl pyridine rubber latex and styrene-butadiene latex. In particular, by using styrene-butadiene latex as an additional latex, it is possible to optimize the composition without losing properties.

[0014] The claimed aqueous dipping composition comprises 4 to 40% by weight (dry weight), preferably 4.5 to 20% by weight (dry weight), particularly preferably 5 to 15% by weight (dry weight) of the at least one rubber latex which is not isoprene rubber latex, based on the total weight of the aqueous dipping composition. The total weight of the aqueous dipping composition also includes the weight of the water of the aqueous composition.

[0015] The claimed aqueous impregnation composition further comprises at least one blocked isocyanate. The at least one blocked isocyanate may be any suitable blocked isocyanate. According to the invention, the blocked isocyanate is an isocyanate compound in which the isocyanate groups are blocked by a blocking agent or by dimerization or association to a higher homologue ("self-blocking"). Preferably, the at least one blocked isocyanate is a polyisocyanate containing thermally dissociated blocked isocyanate groups. According to a preferred embodiment of the present invention, the isocyanate group is blocked with a blocking agent selected from phenol, thiophenol, chlorophenol, cresol, resorcinol, p-sec-butylphenol, p-tert-butylphenol, p-sec-amylphenol, p-octylphenol, p-nonylphenol, tert-butyl alcohol, diphenylamine, dimethylaniline, phthalimide, δ-valerolactam, ε-caprolactam, dialkyl malonate, acetylacetone, alkyl acetoacetate, acetone oxime, methyl ethyl ketone oxime, 3,5-dimethylpyrazole, cyclohexanone oxime, 3-hydroxypyridine, acidic sodium sulfite and a combination thereof.

[0016] According to a preferred embodiment of the present invention, the at least one blocked isocyanate comprises units selected from tetramethylene diisocyanate, hexamethylene diisocyanate, diphenylmethane 4,4'-diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, aromatic diisocyanates including toluene 2,4- or 2,6-diisocyanate, tetramethylxylene diisocyanate, p-xylene diisocyanate, 2,4'- or 4,4'-diisocyanatodiphenylmethane, 1,3- or 1,4-phenylene diisocyanate, and combinations thereof.

[0017] The claimed aqueous impregnation composition comprises 0.1% to 10% by weight (dry weight), preferably 0.2% to 4.5% by weight (dry weight), particularly preferably 0.5% to 3.5% by weight (dry weight), of the at least one blocked isocyanate, based on the total weight of the aqueous impregnation composition. The total weight of the aqueous impregnation composition also includes the weight of the water of the aqueous composition.

[0018] The claimed aqueous impregnation composition further comprises at least one isoprene rubber latex. The at least one isoprene rubber latex can be any suitable isoprene rubber latex known to those skilled in the art. According to a preferred embodiment of the present invention, the isoprene rubber latex is selected from the group consisting of synthetic isoprene rubber latex (IR), natural isoprene rubber latex (NR) and combinations thereof.

[0019] For example, the synthetic isoprene rubber latex can be based on cis / trans-1,4-polyisoprene, 3,4-polyisoprene or 1,2-polyisoprene. Preferably, the isoprene rubber latex is based on cis-1,4-polyisoprene or 3,4-polyisoprene. It is particularly preferred to use cis-1,4-polyisoprene having a cis-1,4 content greater than 90% by weight.

[0020] Natural isoprene rubber latex (hereinafter also referred to as natural rubber latex) can be obtained from any suitable source, for example, from "Hevea Brasiliensis", "Hevea Benthamiana", "Hevea Guianensus", "Manihot Carthaginensis", "Manihot Dichotoma", "Castilla Elastica", "Ficus Elastica", "Funtimia Elastica", "Landolphia Kirkii", "Landolphia Gentilli", "Landolphia Heudelotii", "Landolphia Owariensis", "Crytostegia Grandiflora", "Crytostegia Madagascariansis", "Parthenium Argentatum", "Taraxacum", "Lactuca Serriola", "Willoughbya" or "Hancornia" plants. Natural rubber latex can be produced, for example, by creaming, centrifugation or double centrifugation. Natural rubber latex can have high ammonia (HA), full ammonia (FA) or low ammonia (LA) type, or can be ammonia-free. Natural rubber latex can also be destabilized by using one or more organic acids or substances that release acid, using salts of multivalent cations or applying heat. Natural rubber latex can also be chemically modified and / or can include additional additives such as sulfur or sulfur donors (such as zinc dialkyl dithiocarbamate, tetramethylthiuram disulfide), ZnO, boric acid, lauric acid and combinations thereof by, for example, pre-vulcanization, deproteinization, grafting, hydroxylamine modification. According to a preferred embodiment of the present invention, the at least one isoprene rubber latex is not epoxidized natural rubber latex.

[0021] According to a particularly preferred embodiment of the present invention, a high-ammonia natural rubber latex is used, which preferably originates from the "Hevea brasiliensis" plant.

[0022] The claimed aqueous dipping composition comprises 1 to 20% by weight (dry weight), preferably 2 to 15% by weight (dry weight), particularly preferably 3 to 10% by weight (dry weight), of the at least one isoprene rubber latex, based on the total weight of the aqueous dipping composition. The total weight of the aqueous dipping composition also includes the weight of the water of the aqueous composition.

[0023] The aqueous impregnation composition according to the present invention may further comprise at least one epoxy-containing compound. The at least one epoxy-containing compound may be any suitable epoxy-containing compound, such as glycidyl ether epoxy resin, glycidyl-based glycerol, such as polyglycerol glycidyl ether epoxy resin, sorbitol-based epoxy compound, such as sorbitol epoxy resin, phenol-based novolac epoxy compound, such as bisphenol A epoxy resin, cresol-based novolac epoxy compound, such as meta-cresol epoxy resin, and combinations thereof. According to a preferred embodiment, the at least one epoxy-containing compound is selected from glycidyl-based glycerol, sorbitol-based epoxy compound, phenol-based novolac epoxy compound, cresol-based novolac epoxy compound, and combinations thereof. A particularly suitable example is a polyglycidyl ether based on glycerol, such as Denacol TM EX-313, which is described inter alia in DE 69 722 388 T2.

[0024] The claimed aqueous impregnation composition may contain the at least one epoxy-containing compound in an amount of 0% to 6% by weight (dry weight). According to a first preferred embodiment, the composition does not contain an epoxy-containing compound. This makes the production process of the impregnation composition more direct and also advantageous from a cost point of view. According to another preferred embodiment, the claimed composition contains the at least one epoxy-containing compound. In this case, the epoxy-containing compound is contained in the composition in an amount greater than 0% by weight and up to 6% by weight (dry weight), preferably in an amount of 0.2% to 4% by weight (dry weight), more preferably in an amount of 0.5% to 2.5% by weight (dry weight), based on the total weight of the aqueous impregnation composition. The total weight of the aqueous impregnation composition also includes the weight of the water of the aqueous composition. The addition of such an amount of epoxy-containing compound further improves the adhesion of the textile reinforcement material to the elastomeric compound.

[0025] According to a preferred embodiment of the present invention, the claimed dipping composition comprises 4.5 to 20 wt. % (dry weight) of the at least one rubber latex which is not isoprene rubber latex, 0.2 to 4.5 wt. % (dry weight) of the at least one blocked isocyanate, 2 to 15 wt. % (dry weight) of the at least one isoprene rubber latex, and 0 to 4 wt. % (dry weight) of the at least one epoxy-containing compound, wherein the amounts in wt. % are based on the total weight of the aqueous dipping composition. According to a particularly preferred embodiment, the claimed dipping composition comprises 4.5 to 20 wt. % (dry weight) of the at least one rubber latex which is not isoprene rubber latex, 0.2 to 4.5 wt. % (dry weight) of the at least one blocked isocyanate, 2 to 15 wt. % (dry weight) of the at least one isoprene rubber latex, and 0.2 to 4 wt. % (dry weight) of the at least one epoxy-containing compound, which is preferably selected from glycidyl-based glycerols, sorbitol-based epoxy compounds, phenol-based novolac epoxy compounds, cresol-based novolac epoxy compounds and combinations thereof, wherein the amounts in wt. % are based on the total weight of the aqueous dipping composition.

[0026] According to a further particularly preferred embodiment, the claimed dipping composition comprises 5 to 15 wt.-% (dry weight) of the at least one rubber latex which is not isoprene rubber latex, 0.5 to 3.5 wt.-% (dry weight) of the at least one blocked isocyanate, 3 to 10 wt.-% (dry weight) of the at least one isoprene rubber latex, and 0 to 4 wt.-% (dry weight) of the at least one epoxy-containing compound, wherein the amounts in wt.-% are based on the total weight of the aqueous dipping composition. According to a particularly preferred embodiment, the claimed dipping composition comprises 5 to 15 wt. % (dry weight) of the at least one rubber latex which is not isoprene rubber latex, 0.5 to 3.5 wt. % (dry weight) of the at least one blocked isocyanate, 3 to 10 wt. % (dry weight) of the at least one isoprene rubber latex, and 0.2 to 4 wt. % (dry weight) of the at least one epoxy-containing compound, which is preferably selected from glycidyl-based glycerol, sorbitol-based epoxy compounds, phenol-based novolac epoxy compounds, cresol-based novolac epoxy compounds and combinations thereof, wherein the amounts in wt. % are based on the total weight of the aqueous dipping composition.

[0027] The impregnation composition according to the invention may further comprise a base. More specifically, a base may be added to set the pH of the impregnation composition to a range of 5 to 11, preferably a range of 7 to 10. A pH of at least 5 advantageously avoids the formation of any agglomerates. Preferably, the base is selected from ammonium hydroxide (i.e. an aqueous solution of ammonia), an alkali metal hydroxide (in particular sodium hydroxide) and combinations thereof. The base is preferably a volatile base, which evaporates or a component thereof evaporates during the heat treatment step. The addition of a base may further contribute to the stability of the impregnation composition.

[0028] The aqueous impregnation composition according to the present invention may also contain additional additives. For example, the composition may contain additives selected from waxes, colorants, polymers with carboxylic acid functional groups, catalysts for isocyanate deblocking or trimerization, catalysts for reactions between isocyanates and epoxy- and / or hydroxy-containing compounds or polymers with carboxylic acid functional groups, catalysts for reactions between polymers with carboxylic acid functional groups and epoxy- and / or hydroxy-containing compounds, and combinations thereof. Colorants include pigments and dyes. Suitable waxes include, for example, paraffin wax, microcrystalline wax, synthetic wax, wax from natural sources such as from bees, or combinations thereof. More specifically, the wax may include branched and / or non-branched hydrocarbons, the main fraction (i.e., the middle 80% fraction) of which has a carbon chain length of C15 to C100.

[0029] The polymer with carboxylic acid functional group can be any suitable polymer with carboxylic acid functional group and preferably contains 50 to 100 mol % of monomers containing carboxylic acid groups. According to a preferred embodiment, the polymer with carboxylic acid functional group contains 70 to 100 mol %, particularly preferably 90 to 100 mol % of monomers containing carboxylic acid groups. In a particularly preferred embodiment of the present invention, the polymer with carboxylic acid functional group is based on monomers containing carboxylic acid groups to the extent of 100 mol %, but other functional groups are not excluded. The polymer with carboxylic acid functional group can have any suitable molecular weight. Preferably, the polymer with carboxylic acid functional group has 1,000 to 500,000 g / mol, preferably 3,000 to 100,000 g / mol of weight average molecular weight Mw measured by GPC.

[0030] According to a preferred embodiment of the present invention, the polymer having carboxylic acid functional groups is based on monomers selected from acrylic acid, methacrylic acid, esters of acrylic acid, esters of methacrylic acid, itaconic acid, crotonic acid, cinnamic acid, maleic acid and combinations thereof. In a particularly preferred embodiment, the polymer having carboxylic acid functional groups is an acrylic resin.

[0031] In addition, it is also possible to use carboxylated rubber latex as a polymer with carboxylic acid functional groups, wherein "carboxylation" refers to that the latex carries a carboxylic acid group as a functional group. The rubber latex can be any of the rubber latexes mentioned above, as long as it contains an additional carboxylic acid functional group. In other words, once one of the rubber latexes mentioned above contains a carboxylic acid functional group, it is considered as a polymer with a carboxylic acid functional group within the meaning of the present invention, rather than one of the rubber latexes defined above. For example, ethylene-acrylate rubber latex, carboxylated nitrile rubber latex, carboxylated styrene-butadiene-vinyl pyridine rubber latex and / or carboxylated styrene-butadiene latex can be used as a polymer with a carboxylic acid functional group. If the polymer with a carboxylic acid functional group is a carboxylated rubber latex, the latex preferably contains 1 to 15 mol % of a monomer containing a carboxylic acid group.

[0032] The polymer having carboxylic acid functional groups may contain a polyol as a crosslinking agent, and suitable polymers having carboxylic acid functional groups and a polyol crosslinking agent are available, for example, from BASF Corp. under the trade names Acrodur 950 L and Acrodur DS 3530.

[0033] The claimed aqueous impregnation composition may comprise as an additive an amount of up to 10% by weight (dry weight) of the at least one polymer having carboxylic acid functional groups. According to a preferred embodiment, the aqueous impregnation composition comprises an amount of 0.1% to 2% by weight (dry weight), more preferably an amount of 0.2 to 0.4% by weight (dry weight), based on the total weight of the aqueous impregnation composition, of the at least one polymer having carboxylic acid functional groups. The total weight of the aqueous impregnation composition also includes the weight of the water of the aqueous composition.

[0034] Suitable catalysts for the deblocking or trimerization of isocyanates and for the reaction between isocyanates and epoxy- and / or hydroxyl-containing compounds or polymers having carboxylic acid functional groups are known to those skilled in the art and are described in various references, for example (1) Blank, WJ, He, ZA, Hessell, ET (1999): Catalysis of the Isocyanate-Hydroxyl Reaction by Non-Tin Catalysts. Progress in Organic Coatings, 35 (1–4), 19-29; (2) US 2010 / 0151138 A1; (3) Ward, BD et al. (2019): Aluminium-catalysed isocyanate trimerization, enhanced by exploiting a dynamic coordination sphere. Chem. Commun., 55, 7679-7682; (4) Gürtler, C., Danielmeier, K. (2004): catalyst system for the reaction of carboxylic acids with aliphatic isocyanates. Tetrahedron Letters, 45, 2515-2521; (5) Libni, G., Nasar, AS (2017): Catalysis of Forward and ReverseReactions of ε-Caprolactam-Blocked Polyisocyanate: Double Arrhenius Plots andEquilibrium Temperatures of a Thermally Reversible Reaction. ChemistrySelect, 2, 9586-9594.Suitable catalysts for the reaction between a polymer having carboxylic acid functional groups and an epoxy- and / or hydroxyl-containing compound are known to those skilled in the art and are described in various references, for example (1) Blank, WJ, He, ZA, Picci, M. (2002): Catalysis of the epoxy-carboxyl reaction. Journal of Coatings Technology, 74, 33-41; (2) Matsumoto, K., Yanagi, R., Oe, Y.: Chapter 2: Recent Advances in the Synthesis of Carboxylic Acid Esters. In: Badea, G.-I., Radu, GL (Eds), Carboxylic Acid Key Role in Life Sciences, 2018. When the composition contains a polymer having carboxylic acid functional groups, it is of course preferred to add a catalyst for the reaction between an isocyanate and a polymer having carboxylic acid functional groups and a catalyst for the reaction between a polymer having carboxylic acid functional groups and an epoxy- and / or hydroxyl-containing compound.

[0035] The composition may also include a filler. The optional at least one filler may be any suitable material known in the art for use as a filler. Preferably, the filler used in the composition of the present invention is water dispersible. Suitable examples of fillers are particularly water dispersible inorganic fillers such as oxides, hydroxides, carbonates, sulfates, sulfides, carbon black, graphite, graphene, fullerenes, carbon nanotubes and combinations thereof.

[0036] Suitable oxides include, for example, silicon dioxide, silicates, alkaline earth metal oxides such as calcium oxide and magnesium oxide, zinc oxide, titanium dioxide, aluminum oxide, and combinations thereof. Preferred oxides are silicon dioxide, silicates, aluminum oxide (e.g., commercially available Aerodisp W440, Evonik), titanium dioxide (e.g., commercially available Aerodisp W740X, Evonik), and zinc oxide. Suitable silicon dioxide includes, for example, precipitated silicon dioxide, fumed silicon dioxide, dispersed silicon dioxide, colloidal silicon dioxide, functionalized silicon dioxide, and combinations thereof. The silicon dioxide may have any suitable specific surface area. Preferably, the silicon dioxide used has a surface area of ​​30 to 450 m 2 / g, more preferably a BET specific surface area of ​​120 to 410 m² / g (determined according to ISO 9277:2010). Suitable commercially available silicas include, for example, Aerosil 300 (Evonik; with 300 m² / g 2 / g specific surface area of ​​fumed silica), Aerodisp W7520 (Evonik; with a surface area of ​​200 m 2 / g specific surface area of ​​aqueous dispersion of hydrophilic fumed silica), Levasil CT 16APL (Nouryon; colloidal silica, sodium stabilized, with a surface area of ​​160 m 2 / g specific surface area), Levasil CT 16PNL (Nouryon, colloidal silica, ammonia stabilized, 160 m 2 / g specific surface area) or Dispercoll S3030 / 1 (Covestro, aqueous anionic colloidal solution of amorphous silica, sodium stabilized, 300 m 2 / g specific surface area). Suitable silicates include, for example, alkali metal silicates, aluminosilicates, polymeric silicates, and combinations thereof. The alkali metal silicate is preferably sodium silicate.

[0037] Suitable hydroxides include, for example, alkaline earth metal hydroxides, such as magnesium oxide, aluminum hydroxide, and combinations thereof. Suitable carbonates include, for example, alkaline earth metal carbonates, such as calcium carbonate, magnesium carbonate, and combinations thereof. Suitable sulfates include, for example, alkaline earth metal sulfates, such as barium sulfate. Suitable sulfides include, for example, iron sulfide. Suitable carbon blacks include, for example, acetylene black, thermal black, channel black, gas black, furnace black, lamp black, pyrolytic black, and combinations thereof. The graphite, graphene, fullerene, and carbon nanotube used as fillers according to the present invention may also be any suitable graphite, graphene, fullerene, and carbon nanotube, respectively.

[0038] It should be noted that the above-mentioned fillers can be used in synthetic or pure form, or in natural form. For example, natural minerals containing one or more of the above-mentioned compounds as one or more main components can also be used as fillers. Accordingly, if the filler is calcium carbonate, this can also be used in the form of chalk, dolomite or calcite. If the filler is a silicate, this can also be used in the form of clay, talc, mica powder or kaolin.

[0039] According to a particularly preferred embodiment of the present invention, the at least one filler is selected from the group consisting of silicon dioxide, silicates, carbon black, graphite, graphene, fullerene, carbon nanotubes, alkaline earth metal carbonates, alkaline earth metal oxides, zinc oxide, titanium dioxide, aluminum oxide, alkaline earth metal hydroxides, aluminum hydroxide and combinations thereof. The most preferred fillers according to the present invention are silicon dioxide, silicates, carbon black, zinc oxide and combinations thereof.

[0040] The claimed aqueous impregnation composition may preferably contain 0.02% to 20% by weight (dry weight), more preferably 0.3% to 15% by weight (dry weight), particularly preferably 1 to 10% by weight (dry weight) of the at least one filler, based on the total weight of the aqueous impregnation composition. The total weight of the aqueous impregnation composition also includes the weight of the water of the aqueous composition.

[0041] The composition may further also contain a tackifier and / or a defoamer and / or a wetting agent. These additives may be used in suitable amounts, which generally depend on the textile reinforcement material treated with the aqueous impregnation composition and the processing parameters.

[0042] Compared with the impregnation composition of the prior art, the impregnation composition according to the present invention is substantially free of resorcinol, resorcinol precondensate, formaldehyde and formaldehyde-releasing substances. In the present invention, the term "substantially free of" is understood to mean that these substances are present only in an amount that does not substantially affect the basic characteristics of the composition claimed. For example, the amount of these substances should not exceed the trace amount caused by a certain contamination. Typically, resorcinol, resorcinol precondensate, formaldehyde and formaldehyde-releasing substances should each be included in the impregnation composition claimed in an amount of no more than 0.1% by weight (dry weight) based on the total weight of the aqueous composition, i.e. 0.1% by weight is the maximum amount of each of the above components alone. Preferably, the content of resorcinol, resorcinol precondensate, formaldehyde and formaldehyde-releasing substances in the impregnation composition claimed is 0% by weight. The claimed composition substantially free of resorcinol, resorcinol precondensate, formaldehyde and formaldehyde-releasing substances is advantageous because it avoids the use of these compounds that are harmful to the environment and health.

[0043] The dipping composition according to the present invention may have any suitable weight ratio of rubber latex to the sum of blocked isocyanate, epoxy-containing compound and polymer with carboxylic acid functional group (if present as additive), wherein the rubber latex includes rubber latex other than isoprene rubber latex and isoprene rubber latex. According to a preferred embodiment of the present invention, this ratio is at least 2. According to a particularly preferred embodiment of the present invention, the weight ratio of rubber latex to the sum of blocked isocyanate, epoxy-containing compound and optionally polymer with carboxylic acid functional group is in the range of 3 to 20, or more preferably in the range of 3.5 to 8.

[0044] Blocked isocyanate, epoxy-containing compounds and optional polymers with carboxylic acid functional groups are components that form the resin. It has now been surprisingly found that a weight ratio of at least 2 rubber latex to these components that form the resin is advantageous from a processing perspective, i.e., the composition is easy to handle and can be processed well. In particular, the reduction in the amount of the above-mentioned components that form the resin (by increasing the above-mentioned ratio to a value of at least 2) leads to a reduction in dust in production and a reduction in adhesion to the roller. All these advantages improve the production process. When using a ratio of at least 2, the interaction with the rubber phase is also improved. Finally, using a ratio of at least 2 leads to a reduced stiffness and better flexural properties compared to the prior art compositions using a ratio lower than 2.

[0045] The impregnation composition of the invention may have any suitable solids content. Preferably, the composition has a solids content of from 5 to 30 wt% (dry weight), preferably from 7 to 27 wt% (dry weight).

[0046] The impregnation composition of the present invention can be prepared by any suitable method. Generally, the various components of the impregnation composition (in solid form or in the form of an aqueous solution) are simply combined to produce a composition. The various components can be combined simultaneously or added one by one, or the various components can be added in groups or added in any suitable manner known to the technician. For all methods of preparing the impregnation composition claimed, it is generally advantageous to mix the various components under stirring. In addition, it is also preferred to add the at least one rubber latex that is not isoprene rubber latex and the at least one isoprene rubber latex at a pH of 5 to 11 to avoid forming agglomerates. When the isoprene rubber latex used is natural rubber latex, this is particularly important because this type of latex is most prone to coagulation. The preparation of the impregnation composition claimed is usually carried out near ambient temperature, i.e. in the range of 20°C to 25°C. However, it is also possible to prepare (i.e., mixing of the various components) at lower temperatures, preferably in the range of 5°C to less than 20°C, or at higher temperatures, preferably in the range of greater than 25°C to 45°C.

[0047] According to a particularly preferred embodiment of the present invention, the method for preparing the claimed impregnation composition comprises the following steps: (i) providing water, (ii) optionally adding a base, (iii) optionally adding the at least one polymer having carboxylic acid functional groups, (iv) optionally adding the at least one epoxy-containing compound, (v) adding the at least one blocked isocyanate, (vi) adding the at least one rubber latex different from isoprene rubber latex, (vii) adding the at least one isoprene rubber latex, and (viii) optionally adding one or more additives and / or one or more fillers.

[0048] The invention further relates to the use of the aqueous impregnation composition according to the invention for coating a textile reinforcement material. Such a textile reinforcement material may be any suitable textile reinforcement. According to a preferred embodiment of the invention, the textile reinforcement material is based on a material selected from the group consisting of polyester, polyamide, polyurethane, glass, carbon, cellulose, polycarbonate, polyketone and combinations thereof. Suitable polyesters include, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyethylene furandicarboxylate (PEF). Examples of polyamides include nylon-4,6 (PA4.6), nylon-4,10 (PA 4.10), nylon-6 (PA 6), nylon-6,6 (PA 6.6 polyhexamethylene adipamide), nylon-6,12 (PA 6.12), nylon-10,10 (PA 10.10) and nylon-12,12 (PA 12.12). Suitable polyamides further include aromatic polyamides, such as aramid, in particular meta-aramid, para-aramid and mixtures of meta-aramid and para-aramid. Suitable celluloses include, for example, regenerated cellulose (in particular viscose or rayon) and cellulose esters. The most preferred materials for textile reinforcement are polyester, rayon, aramid, nylon and combinations thereof.

[0049] It is also possible to use textile reinforcement materials which have been activated by means of an adhesive. Suitable adhesive-activated (aa) reinforcement materials are known to the person skilled in the art. For example, the textile reinforcement material may be adhesive-activated aramid.

[0050] The fabric reinforcement material can be in any suitable form. For example, the fabric reinforcement material can be in the form of a monofilament or multifilament textile cord, or in the form of a flat yarn structure such as a tape based on a monofilament or multifilament yarn. According to a preferred embodiment of the present invention, the fabric reinforcement material comprises a cord having at least one twisted yarn. Suitable fineness (denier in dtex) and the manner in which the cord and the yarn are twisted are known in the prior art. For example, the denier of each yarn can be 200 to 5000 dtex, and the twist of the yarn and the cord can be 100 to 800 t / m. The fabric reinforcement material can also be made of cords each made of a yarn, which means that a twisted yarn constitutes a cord. Alternatively, the cord may also be made of at least two, more preferably just two yarns. According to another preferred embodiment of the present invention, the fabric reinforcement material is in the form of a flat yarn structure such as a tape. The shape of the filaments can be variable, and the final shape of the yarn itself can also be variable. The dtex of the filaments can be in any suitable range and is preferably 1 to 30 dtex.

[0051] The present invention further relates to a method for coating a textile reinforcement material, comprising the steps of: treating the textile reinforcement material with an impregnation composition according to the present invention; and heat treating the composition. The textile reinforcement material used in this method can be any suitable textile reinforcement material. Preferably, the textile reinforcement material is the one described above. Treatment with the impregnation composition can be carried out in any suitable manner known to those skilled in the art. For example, the treatment can be carried out by impregnating, spraying or applying the impregnation composition to the textile reinforcement material with a suitable device, such as a brush or the like. Preferably, the treatment is carried out by impregnation, for example by preparing a bath containing the impregnation composition and immersing the textile reinforcement material in such a bath. It is also possible to carry out two or more steps of treating the textile reinforcement material with the impregnation composition according to the present invention. According to a particularly preferred embodiment of the present invention, the textile reinforcement material is impregnated twice with the impregnation composition according to the present invention.

[0052] The step of heat treating the composition refers to heat treating the textile reinforcement material that has been treated with the composition in the previous step. The heat treatment can be carried out at any suitable temperature. According to a preferred embodiment, the heat treatment is carried out at a temperature of 60 to 260° C., more preferably 160 to 250° C. The heat treatment can be carried out by any suitable means. Particularly preferably, the heat treatment is carried out by hot-drawing. This can be carried out using known devices, in particular, for example, a 1-zone or 2-zone furnace, through which the textile reinforcement material preferably passes continuously. According to a preferred embodiment of the method according to the invention, two or more heat treatments at the same or different temperatures are carried out successively.

[0053] Usually, it is sufficient to carry out only one coating step. However, depending on the textile reinforcement material used and the desired properties, an additional activation step may optionally be carried out before the above-mentioned treatment with the impregnation composition claimed. Especially in the case of non-preactivated textile materials, it is preferred to treat the textile reinforcement material in a bath containing one or more epoxy compounds and / or one or more polyisocyanate compounds before treating with the impregnation composition according to the invention. This results in an additional impregnation step, but at the same time further optimizes the combined activation of the textile reinforcement material for attachment to the rubber mixture / rubber coating mixture. According to a particularly preferred embodiment of the present invention, the textile reinforcement material is preactivated by means of a pre-impregnation step in a bath containing one or more epoxy compounds and / or one or more polyisocyanate compounds, followed by a single impregnation with the composition according to the invention.

[0054] The invention further relates to a coated textile reinforcement material obtainable by the above process.

[0055] A further advantage of the invention is that the coated textile reinforcement material, in particular the cord, can be provided in various colors by adding colorants, in particular pigments (which are water-dispersible) and / or dyes (which are soluble in water). This can be used, for example, for better marketing of the product or for further processing of the coated textile reinforcement material. For example, the coloring of the coated textile reinforcement material can be used to improve differentiation in further processing, still with the possibility of checking the quality of the impregnation, for example if the impregnation liquid is well distributed and there are no damages on the surface.

[0056] The present invention further relates to an elastomeric article comprising (i) at least one elastomeric compound and (ii) a coated textile reinforcement obtained by the above method or a textile reinforcement coated with the heat-treated impregnated composition as claimed. The elastomeric article may be any suitable elastomeric article. Preferably, the elastomeric article is a tire or a rubber article, such as a belt, a conveyor belt, a transmission belt, a drive belt, a hose, a strip belt, a transport belt or a bellows.

[0057] The elastomeric article according to the present invention may be obtained by any suitable method. For example, such an elastomeric article may be obtained by a method comprising the steps of: (i) providing a coated textile reinforcement material as described above, (ii) combining the coated textile reinforcement material with a rubber coating mixture to produce a green elastomeric article, and (iii) vulcanizing the green elastomeric article to produce an elastomeric article comprising the coated textile reinforcement material and the elastomeric compound.

[0058] According to step (ii) of this method, the coated textile reinforcement material is combined with the rubber coating mixture. This combination can be carried out, for example, by coating the coated textile reinforcement material with the rubber coating mixture, or by calendering the coated textile reinforcement material with the rubber coating mixture. It is also possible to press the coated textile reinforcement material into the rubber coating mixture. The rubber coating mixture can be any suitable rubber coating mixture.

[0059] Preferably, the rubberizing mixture comprises at least one diene rubber. The diene rubber may be any suitable diene rubber known to the skilled person. Preferably, the rubberizing mixture comprises at least one diene rubber selected from natural polyisoprene (NR), synthetic polyisoprene (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR) and combinations thereof. For example, the polyisoprene (IR, NR) may be cis-1,4-polyisoprene or 3,4-polyisoprene. However, it is preferred to use cis-1,4-polyisoprene with a cis-1,4 content of > 90% by weight. Firstly, it is possible to obtain such a polyisoprene by stereospecific polymerization in solution with a Ziegler-Natta catalyst or using finely divided alkyl lithium. Secondly, natural rubber (NR) is such a cis-1,4-polyisoprene; the cis-1,4 content in natural rubber is greater than 99% by weight. Polybutadiene (BR) can be cis-1,4-polybutadiene or vinyl polybutadiene (vinyl content is about 10% to 90% by weight). It is preferred to use cis-1,4-polybutadiene with a cis-1,4 content greater than 90% by weight, which can be prepared, for example, by solution polymerization in the presence of a rare earth catalyst. Styrene-butadiene copolymer (SBR) can be a solution-polymerized styrene-butadiene copolymer (S-SBR) having a styrene content of about 10% to 45% by weight based on the polymer and a vinyl content of 10% to 70% by weight (based on the entire polymer, the content of 1,2-bonded butadiene), which can be prepared, for example, using alkyl lithium in an organic solvent. S-SBR can also be coupled and end-group modified. Alternatively, it is possible to use emulsion-polymerized styrene-butadiene copolymers (E-SBR) and mixtures of E-SBR and S-SBR. The styrene content of E-SBR is approximately 15 to 50% by weight, and it is possible to use products known in the art obtained by copolymerization of styrene and 1,3-butadiene in aqueous emulsion.

[0060] The diene rubbers used in the mixture, in particular the styrene-butadiene copolymers, can also be used in partially or fully functionalized form. The functionalization can be carried out with groups which can interact with the fillers used, in particular with fillers carrying OH groups. The functionalization can be, for example, those using hydroxyl groups and / or epoxy groups and / or siloxane groups and / or amino groups and / or phthalocyanine groups and / or carboxyl groups and / or silane sulfide groups.

[0061] The rubberized mixture preferably contains 25 to 100 phr, more preferably 50 to 100 phr, even more preferably 70 to 100 phr of diene rubber. According to a particularly preferred embodiment, the rubberized mixture contains 100 phr of at least one natural polyisoprene (NR) and / or synthetic polyisoprene (IR), which means that mixtures of NR and IR are also conceivable. According to another particularly preferred embodiment, the rubberized mixture contains 25 to 85 phr of at least one natural and / or synthetic polyisoprene, 15 to 50 phr of at least one butadiene rubber and / or 15 to 50 phr of at least one styrene-butadiene rubber. With these rubbers in particular, and in particular in the reinforcement plies of motor vehicle tires, the rubberized mixture is found to have excellent physical properties in terms of processability, service life and tear properties, while achieving a sufficient degree of bonding.

[0062] The rubber coating mixture preferably further comprises at least one filler selected from carbon black, silica and combinations thereof. This filler is preferably included in the rubber coating mixture in an amount of 20 to 90 phr, more preferably in an amount of 40 to 80 phr. The expression phr (parts by weight relative to every 100 parts of rubber) used herein is a standard unit of the amount of a blending formula in the rubber industry. The dosage of the weight parts of each substance is always based on the total mass of all rubbers present in the mixture as 100 parts by weight. The mass of all rubbers present in the mixture adds up to 100. The rubber coating mixture may further comprise 0.1 to 10 phr of additional fillers, such as aluminosilicates, chalk, starch, magnesium oxide, titanium dioxide, rubber gel, carbon nanotubes (CNT), graphite and graphene and combinations thereof. However, preferably, the rubber coating mixture does not contain these additional fillers, i.e., contains preferably 0 to 0.001 phr of these additional fillers.

[0063] The coating mixture preferably further comprises at least one additive. Suitable additives include aging stabilizers, activators, waxes, resins, especially tackifying resins other than plasticizer resins, plasticizing aids, processing aids, plasticizers, and combinations thereof.

[0064] The method for producing the elastomeric article further comprises a vulcanization step (iii). Vulcanization can be carried out in the presence of sulfur and / or a sulfur donor, and some sulfur donors can simultaneously act as vulcanization accelerators. Sulfur or sulfur donors can be added to the rubberized mixture in an amount commonly used by those skilled in the art (0.4 to 8 phr, preferably 0.4 to 4 phr of sulfur). Vulcanization can also be carried out in the presence of a very small amount of sulfur in combination with a sulfur donor substance. Vulcanization can be carried out at any suitable temperature, preferably at a temperature of 100 to 250° C., preferably at a temperature of 130 to 180° C., wherein a pressure of 10 to 200 bar can be optionally applied.

[0065] The present invention is further described below with reference to examples, but the examples do not limit the scope of the present invention.

[0066] Example :

[0067] Examples 1 and 2 :

[0068] Examples 1 and 2 refer to experiments carried out in a laboratory impregnation unit. Cords made of polyester (polyethylene terephthalate (PET), 2-ply, 1440 dtex, 375x375 twist, no adhesive activation) were pretreated by impregnating the cords into a pre-impregnation composition containing 95.26% by weight of water, 0.90% by weight of Denacol EX313 (epoxy compound) and 3.84% by weight of Grilbond IL-6 (polyisocyanate compound) and heat treated at a temperature ranging from 210 to 250°C. After treatment with the pre-impregnation composition, the cords were impregnated with aqueous impregnation compositions according to Example 1 (reference example) and Example 2 (according to the invention), respectively. The impregnation compositions of Examples 1 and 2 were prepared by adding the various components in the following order of addition in the amounts given in Table 1 below under stirring at ambient temperature (if a chemical was not part of the recipe according to Table 1, the subsequent component was added and so on):

[0069] Water → Epoxide → Isocyanate → SBR latex → VP latex → NR latex.

[0070] The dipped cords were then passed through two additional ovens. The temperature of the first oven was maintained at 170 to 220°C; the temperature of the second oven was maintained at 200 to 250°C. Note that Table 1 provides the total amounts of added components (parts by weight) rather than dry weights.

[0071] Table 1 :

[0072] Ex. 1 (reference) Ex. 2 <![CDATA[VP latex a) > 37.32 23.27 <![CDATA[SBR latex b) > 6.59 7,02 <![CDATA[NR latex c) > - 9.15 <![CDATA[Isocyanate d) > 4.71 4.71 <![CDATA[Epoxide e) > 1.67 1.67 water 49.71 54.17 total 100 100 Latex / resin 4.0 4.0 Solid content of impregnation liquid% 22.5 23.0

[0073] a) copolymer of butadiene, styrene and 2-vinylpyridine, containing about 15% by weight of vinylpyridine bound in the polymer, aqueous dispersion, 41% by weight;

[0074] b) Styrene-butadiene copolymer, aqueous dispersion, 41% by weight;

[0075] c) CentexHF: natural rubber latex, high filterability, high ammonia, aqueous dispersion, 60 wt% (CentroTrade);

[0076] d)Grilbond IL-6: Caprolactam-terminated 4,4'-diphenylmethane diisocyanate, aqueous dispersion, 60 wt% (EMS-GRILTECH);

[0077] e) Denacol EX313: Polyglycidyl ether based on glycerol (Nagase Chemtex).

[0078] After impregnation and subsequent hot drawing, the reinforcements were each covered with a rubberizing mixture according to Table 2. Test specimens comprising two fabric plies bonded with rubber were made to measure the peeling force required to separate the two fabric plies bonded with rubber. The cord density was 90 epdm (ends per decimeter). This composite was then cured at 170°C under pressure (7.5 bar) for 10 minutes to obtain the final reinforced material / reinforcement.

[0079] Table 2

[0080] Composition of the glue coating mixture Amount, phr Natural rubber 70 SBR 30 N660 Carbon Black 50 Zinc Oxide 4 Stearic acid 2 Oil 5 Penacolite (resorcinol-formaldehyde) 3 Hexamethoxymethylmelamine 2 2,2,4-Trimethyl-1,2-dihydroquinoline (TMQ) 1.8 sulfur 2.5 2,2'-Dibenzothiazyl disulfide (MBTS) 0.8

[0081] For all reinforcements described, bonding tests using the above-described rubber coating mixture were carried out according to ISO 36:2011. The vulcanized samples were heated to 120° C. for 30 minutes and the bonding test was carried out within 30 seconds after removal from the oven. The results are provided in Table 3, where the force values ​​obtained are given in % relative to the initial force values ​​of Reference Example 1 normalized to 100%.

[0082] The evaluation of the bonding strength was carried out according to DIN ISO 6133:2004-05, procedure B. In addition, the separation area of ​​the test specimens was visually evaluated on a scale of 1 to 5 using the following coverage rating.

[0083] 1 0% completely rubber-free

[0084] 2 25% Mainly free of rubber

[0085] 3 50% Half covered by rubber

[0086] 4 75% Mainly covered with rubber

[0087] 5 100% completely covered with rubber.

[0088] The face with the worst coverage was used for this evaluation. In the determination of the coverage rating, half ratings (i.e. 3.5) were also allowed. For each example, the reported binding force and the reported coverage are in each case the average values ​​from three measurements. The results are also provided in Table 3.

[0089] In addition, the storage stability / shelf life stability of the textile reinforcement material treated with the impregnation composition according to the present invention is also evaluated. As a test of the storage stability of the treated textile reinforcement material under real conditions, an accelerated aging test is applied by aging the treated textile reinforcement material in an air circulation oven at 60°C for 72 hours. For the accelerated aging test, the sample wound on a suitable carrier is placed in an oven to avoid stretching, twisting, untwisting or forming a loop. The winding is loose enough so that possible shrinkage can occur during the drying process without causing tension on the sample. The aged treated textile reinforcement material is then tested in the same manner as the fresh textile reinforcement material treated with the impregnation composition according to the present invention. The results are also provided in Table 3. The resulting force value is still given in % relative to the initial force value (set to 100%) of Reference Example 1.

[0090] Table 3 :

[0091] Ex. 1 (reference) Ex. 2 Initial adhesion[%] 100.0 120.8 Initial coverage 3.5 4.5 Aging adhesion (72h) 64.8 129.5 Aging coverage (72h) 1.5 4.7

[0092] As can be seen in Table 3, the textile reinforcement material treated with the impregnation composition according to the invention (Example 2) shows improved initial bond as well as aged coverage and bond compared to the prior art composition according to Reference Example 1.

[0093] Examples 3 and 4 :

[0094] Examples 3 and 4 refer to experiments carried out in a production impregnation unit. Cords made of rayon (2-ply, 2440 dtex, 340x340 twist, braid made of cords at 104 epdm (ends per decimeter, measure of the cord density in a fabric ply)) were impregnated with aqueous impregnation compositions according to Example 3 (reference example) and Example 4 (according to the invention) respectively and passed through four ovens. The impregnation compositions of Examples 3 and 4 were prepared by adding the various components in the following order of addition in the amounts given in Table 4 below under stirring at ambient temperature (if a chemical was not part of the recipe according to Table 4, the subsequent component was added and so on):

[0095] Water → Ammonia → Carboxylic acid resin → Epoxy compound → Isocyanate → SBR latex → VP latex → NR latex

[0096] The temperature of the first oven was maintained at 170 to 220° C.; the temperatures of the second, third and fourth ovens were independently maintained at 200 to 250° C. Note that Table 4 provides the total amounts of added components (parts by weight) rather than dry weights.

[0097] Table 4 :

[0098] Ex. 3 (Ref.) Ex. 4 <![CDATA[VP latex a) > 29.00 17.55 <![CDATA[SBR latex f) > 5.12 7.27 <![CDATA[NR latex g) > - 6.36 <![CDATA[Isocyanate d) > 3.40 3.40 <![CDATA[ammonia h) > 0.60 0.60 <![CDATA[Carboxylic acid resin i) > 0.40 0.40 <![CDATA[Epoxide j) > 0.30 0.30 water 61.18 64.12 total 100 100 Latex / resin 6.0 6.3 Solid content of impregnation liquid% 17.9 18.9

[0099] a) d) See above with respect to Examples 1 and 2;

[0100] f) Styrene-butadiene copolymer, aqueous dispersion, 67% by weight;

[0101] g) Natural rubber latex, high ammonia, aqueous dispersion, 60 wt% (Neoquimica);

[0102] h) Ammonium hydroxide, aqueous solution, 25 wt %;

[0103] i) Acrodur 950L: polyacrylate, aqueous solution, 50 wt. % in water (BASF);

[0104] j) Grilbond G1701: Polyglycidyl ether based on glycerol (EMS-GRILTECH).

[0105] After impregnation and subsequent hot drawing, the reinforcements were each covered with a rubber coating mixture according to Table 2. The rayon material was dried (1 hour, 105°C) according to ASTM D885 before sample preparation. A test specimen comprising two fabric plies bonded with rubber was made to measure the peel force required to separate the two fabric plies bonded with rubber. The cord density was 90 epdm (ends per decimeter). This composite was then cured at 170°C under pressure (7.5 bar) for 10 minutes to obtain the final reinforced material / reinforcement.

[0106] The initial coverage and bonding of the resulting reinforcements were tested as described above for Examples 1 and 2. In addition, the storage stability / shelf life stability of the textile reinforcements treated with the impregnation compositions according to the invention were also evaluated. To test the storage stability, the samples were kept in closed moisture-proof dark bags at ambient temperature to protect the samples from light and environmental changes for 4 months and 12 months, respectively. The results are provided in Table 5, where the resulting force values ​​are given in % relative to the initial force values ​​of Reference Example 3 normalized to 100%.

[0107] Table 5 :

[0108] Ex. 3 (reference) Ex. 4 Initial adhesion[%] 100.0 109.4 Initial coverage 4.5 4.7 Aging adhesion (4 months) 64.9 104.0 Aging coverage (4 months) 1.5 4.5 Aging Adhesion (12 months) nd 102.4 Aging coverage (12 months) nd 4.7

[0109] As can be seen in Table 5, the textile reinforcement material treated with the impregnation composition according to the invention exhibits improved initial and aged bonding and coverage (compare Reference Example 3 with Example 4).

[0110] Examples 5 to 7 :

[0111] Examples 5 to 7 refer to experiments carried out in a laboratory impregnation unit. Cords made of rayon (2-ply, 2440 dtex, 340x340 twist) were impregnated with aqueous impregnation compositions (see Table 6) according to Example 5 (reference example) and Examples 6 and 7 (according to the invention), respectively, and passed through four ovens. The impregnation compositions of Examples 5 to 7 were prepared by adding the various components in the following order of addition in the amounts given in Table 6 below under stirring at ambient temperature (if a chemical was not part of the recipe according to Table 6, the subsequent component was added, and so on):

[0112] Water → ammonia → carboxylic acid resin → epoxy compound → isocyanate → SBR latex → VP latex → NR latex.

[0113] The temperature of the first oven was maintained at 170° C. to 220° C., and the temperatures of the second, third, and fourth ovens were independently maintained at 200° C. to 250° C. Note that Table 6 provides the total amounts of added components (parts by weight) rather than dry weights.

[0114] Table 6 :

[0115] Ex. 5 (reference) Ex. 6 Ex. 7 <![CDATA[VP latex a) > 29.00 17.55 17.55 <![CDATA[SBR latex f) > 5.12 7.27 7.27 <![CDATA[NR latex g) > - 6.36 6.36 <![CDATA[Isocyanate d) > 3.40 3.40 3.40 <![CDATA[ammonia h) > 0.60 - - <![CDATA[Carboxylic acid resin i) > 0.40 - - <![CDATA[Epoxide j) > 1.20 1.20 - water 60.28 64.22 65.42 total 100 100 100 Latex / resin 4.5 4.9 7.8 Solid content of impregnation liquid% 18.8 19.6 18.4

[0116] a) d) f) g) h) i) j) See above with respect to Examples 1 to 4.

[0117] After impregnation and subsequent hot drawing, the reinforcements were each covered with a rubber coating mixture according to Table 2. The rayon material was dried (1 hour, 105°C) according to ASTM D885 before sample preparation. A test specimen comprising two fabric plies bonded with rubber was made to measure the peel force required to separate the two fabric plies bonded with rubber. The cord density was 90 epdm (ends per decimeter). This composite was then cured at 170°C under pressure (7.5 bar) for 10 minutes to obtain the final reinforced material / reinforcement.

[0118] The resulting reinforcements were tested as described above for Examples 1 and 2. The results are provided in Table 7, where the resulting force values ​​are given in % relative to the initial force value of Reference Example 5 normalized to 100%.

[0119] Table 7 :

[0120] Ex. 5 (reference) Ex. 6 Ex. 7 Initial adhesion[%] 100.0 105.9 108.1 Initial coverage 4.3 4.8 5.0 Aging adhesion (72h) 72.9 99.5 97.3 Aging coverage (72h) 1.0 4.0 4.0

[0121] As can be seen in Table 7, the textile reinforcement material treated with the impregnation composition according to the invention exhibits improved initial and aged bonding and coverage (compare Reference Example 5 with Examples 6 and 7).

[0122] The following items are further disclosed herein:

[0123] Item 1. An aqueous impregnating composition for coating a textile reinforcement material, comprising

[0124] 4 to 40 wt. % (dry weight) of at least one rubber latex, provided that the rubber latex is not isoprene rubber latex,

[0125] 0.1% to 10% by weight (dry weight) of at least one blocked isocyanate,

[0126] 1 to 20 wt. % (dry weight) of at least one isoprene rubber latex, and

[0127] 0% to 6% by weight (dry weight) of at least one epoxy-containing compound,

[0128] wherein the amounts in wt % are based on the total weight of the aqueous impregnation composition, and

[0129] The composition is substantially free of resorcinol, resorcinol precondensate, formaldehyde and formaldehyde-releasing substances.

[0130] Item 2. The dipping composition according to Item 1, wherein the at least one rubber latex that is not isoprene rubber latex is selected from styrene-butadiene rubber latex, ethylene-propylene-diene rubber latex, butyl rubber latex, styrene-butadiene-vinyl pyridine rubber latex, nitrile rubber latex, chloroprene rubber latex, butadiene rubber latex, functionalized rubber latex and combinations thereof.

[0131] Item 3. The impregnation composition according to Item 1 or 2, wherein the at least one blocked isocyanate comprises units selected from tetramethylene diisocyanate, hexamethylene diisocyanate, diphenylmethane 4,4'-diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, aromatic diisocyanates comprising toluene 2,4- or 2,6-diisocyanate, tetramethylxylene diisocyanate, p-xylene diisocyanate, 2,4'- or 4,4'-diisocyanatodiphenylmethane, 1,3- or 1,4-phenylene diisocyanate, and combinations thereof.

[0132] Item 4. The dipping composition according to any one of items 1 to 3, wherein the at least one isoprene rubber latex is selected from the group consisting of synthetic isoprene rubber latex (IR), natural isoprene rubber latex (NR), and combinations thereof.

[0133] Item 5. The impregnation composition according to any one of Items 1 to 4, comprising

[0134] 4.5 to 20 wt. % (dry weight) of at least one rubber latex that is not isoprene rubber latex,

[0135] 0.2% to 4.5% by weight (dry weight) of the at least one blocked isocyanate,

[0136] 2 to 15 wt. % (dry weight) of said at least one isoprene rubber latex, and

[0137] 0.2 to 4 wt. % (dry weight) of at least one epoxy-containing compound selected from the group consisting of glycidyl-based glycerols, sorbitol-based epoxy compounds, phenol-based novolac epoxy compounds, cresol-based novolac epoxy compounds, and combinations thereof,

[0138] The amounts in wt % are based on the total weight of the aqueous impregnation composition.

[0139] Item 6. The impregnation composition according to any one of Items 1 to 4, which does not contain an epoxy-containing compound.

[0140] Item 7. The impregnation composition according to any one of items 1 to 6, further comprising a base, preferably selected from ammonium hydroxide, sodium hydroxide and a combination thereof.

[0141] Item 8. The impregnation composition according to any one of Items 1 to 7, further comprising an additive selected from waxes, colorants, polymers having carboxylic acid functional groups, and combinations thereof, and / or a filler selected from silica, silicates, carbon black, graphite, graphene, fullerenes, carbon nanotubes, alkaline earth metal carbonates, alkaline earth metal oxides, zinc oxide, titanium dioxide, aluminum oxide, alkaline earth metal hydroxides, aluminum hydroxide, and combinations thereof.

[0142] Item 9. The impregnation composition according to any one of items 1 to 8, which has a solid content of 5 to 30 wt. % (dry weight), preferably 7 to 27 wt. %.

[0143] Item 10. The dipping composition according to any one of items 1 to 9, wherein the weight ratio of the rubber latex to the sum of the blocked isocyanate, the epoxy-containing compound and the optional polymer having a carboxylic acid functional group is at least 2.

[0144] Item 11. Use of the aqueous impregnation composition according to any one of items 1 to 10 for coating a textile reinforcement material, preferably a textile reinforcement material selected from polyester, polyamide, polyurethane, glass, carbon, cellulose, polycarbonate, polyketone and combinations thereof.

[0145] Item 12. A method for coating a textile reinforcement material, comprising the following steps

[0146] - treating the textile reinforcement material with an impregnation composition according to any one of items 1 to 11, preferably by impregnation; and

[0147] - thermally treating the composition, preferably at a temperature ranging from 60 to 260°C.

[0148] Item 13. A coated textile reinforcement material obtained by the method according to Item 12.

[0149] Item 14. An elastomeric article comprising (i) at least one elastomeric compound and (ii) a coated textile reinforcement material according to Item 13 or a textile reinforcement material coated with a heat-treated impregnation composition according to any one of Items 1 to 10.

[0150] Item 15. The elastomeric article according to Item 14, which is a tire or a rubber article such as a belt, a conveyor belt, a transmission belt, a drive belt, a hose, a strip, a conveyor belt and a bellows.

Claims

1. An aqueous impregnation composition for coating a textile reinforcement material, comprising 4 to 40% by dry weight of at least one rubber latex, provided that the rubber latex is not isoprene rubber latex, 0.1 to 10% by dry weight of at least one blocked isocyanate, 2 to 15% by dry weight of at least one isoprene rubber latex, 0% to 6% by dry weight of at least one epoxy-containing compound, and optionally a polymer having carboxylic acid functional groups, wherein the amounts in dry weight % are based on the total weight of the aqueous impregnation composition, wherein the composition is free of resorcinol, resorcinol precondensate, formaldehyde and formaldehyde-releasing substances, and wherein the weight ratio of the rubber latex to the sum of the blocked isocyanate, the epoxy-containing compound and the optional polymer having carboxylic acid functional groups is 3 to 20.

2. The dipping composition according to claim 1, wherein the at least one rubber latex that is not isoprene rubber latex is selected from the group consisting of styrene-butadiene rubber latex, ethylene-propylene-diene rubber latex, butyl rubber latex, styrene-butadiene-vinyl pyridine rubber latex, nitrile rubber latex, chloroprene rubber latex, butadiene rubber latex, functionalized rubber latex, and combinations thereof.

3. The impregnation composition according to claim 1 or 2, wherein the at least one blocked isocyanate comprises units selected from tetramethylene diisocyanate, hexamethylene diisocyanate, diphenylmethane 4,4'-diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, aromatic diisocyanates including toluene 2,4- or 2,6-diisocyanate, tetramethylxylylene diisocyanate, p-xylene diisocyanate, 2,4'- or 4,4'-diisocyanatodiphenylmethane, 1,3- or 1,4-phenylene diisocyanate, and combinations thereof.

4. The dipping composition according to claim 1 or 2, wherein the at least one isoprene rubber latex is selected from the group consisting of synthetic isoprene rubber latex (IR), natural isoprene rubber latex (NR), and combinations thereof.

5. An impregnation composition according to claim 1 or 2, comprising 4.5% to 20% by dry weight of said at least one rubber latex which is not isoprene rubber latex, 0.2% to 4.5% by dry weight of said at least one blocked isocyanate, 2% to 15% by dry weight of said at least one isoprene rubber latex, and 0.2% to 4% by dry weight of at least one epoxy-containing compound selected from the group consisting of glycidyl-based glycerols, sorbitol-based epoxides, phenol-based novolac epoxides, cresol-based novolac epoxides, and combinations thereof, The amounts stated in dry weight % are based on the total weight of the aqueous impregnation composition.

6. The impregnation composition according to claim 1 or 2, further comprising a base.

7. The impregnation composition according to claim 6, wherein the base is selected from the group consisting of ammonium hydroxide, sodium hydroxide and combinations thereof.

8. The impregnation composition according to claim 1 or 2, further comprising an additive selected from waxes, colorants, catalysts for isocyanate deblocking or trimerization, catalysts for the reaction between isocyanates and epoxy- and / or hydroxyl-containing compounds or polymers having carboxylic acid functional groups, catalysts for the reaction between polymers having carboxylic acid functional groups and epoxy- and / or hydroxyl-containing compounds, and combinations thereof, and / or fillers selected from silica, silicates, carbon black, graphite, graphene, fullerenes, carbon nanotubes, alkaline earth metal carbonates, alkaline earth metal oxides, zinc oxide, titanium dioxide, aluminum oxide, alkaline earth metal hydroxides, aluminum hydroxide, and combinations thereof.

9. An impregnation composition according to claim 1 or 2, having a solids content of 5 to 30% by dry weight.

10. An impregnation composition according to claim 1 or 2, having a solids content of 7 to 27% by dry weight.

11. The dipping composition according to claim 1, wherein the weight ratio of the rubber latex to the sum of the blocked isocyanate, the epoxy-containing compound and the optional polymer having carboxylic acid functional groups is from 3.5 to 8.

12. Use of an aqueous impregnation composition according to any one of claims 1 to 11 for coating textile reinforcement materials.

13. The use according to claim 12, wherein the textile reinforcement material is selected from the group consisting of polyester, polyamide, polyurethane, glass, carbon, cellulose, polycarbonate, polyketone and combinations thereof.

14. A method for coating a textile reinforcement material, comprising the following steps - treating a textile reinforcement material with an impregnation composition according to any one of claims 1 to 11; and - heat treating said composition.

15. The method according to claim 14, wherein the treatment is impregnation and the heat treatment is carried out at a temperature of 60 to 260°C.

16. A coated textile reinforcement material obtainable by the process according to claim 14 or 15.

17. An elastomeric article comprising (i) at least one elastomeric compound and (ii) a coated textile reinforcement material according to claim 16 or a textile reinforcement material coated with a heat-treated impregnation composition according to any one of claims 1 to 11.

18. Elastomeric article according to claim 17, which is a tire or a rubber article.

19. The elastomeric article according to claim 17, which is a hose, a belt or a bellows.