Rubber composition containing phloroglucinol resin for heavy vehicle tire treads

Abstract

A silane-based additive, rubber formulations comprising the additive, tires having a tread portion made with the additive, and methods of forming these products are provided. Uncured rubber formulations according to preferred embodiments of the present invention include (1) a rubber host polymer or polymer blend, such as natural rubber and / or synthetic rubber; (2) reinforced silicon dioxide filler; (3) a methylene donor compound; (4) a silane containing one or more of the aforementioned mesh-forming polymer moieties, and (5) a phloroglucinol resin. In particular, the mesh is preferably able to be generated in situ. The cured rubber formulation should comprise silica, in the rubber matrix, having a load-bearing path-reinforced interpenetrating polymer grid coupled thereto, rather than being coupled directly to rubber chains through sulfide bonds.

Description

Technical Field

[0001] The present invention generally relates to rubber compounds for heavy vehicle tires such as large trucks and buses. More specifically, the present invention relates to an environmentally friendly, energy-saving rubber compound for truck and bus tire treads that does not contain resorcinol but unexpectedly provides excellent rolling resistance properties for such rubber compounds. Background Art

[0002] Due to the Corporate Average Fuel Economy (CAFE) standards, the Greenhouse Gas (GHG) Protocol and other legislation issued by the National Highway Traffic Safety Administration (NHTSA) and the Environmental Protection Agency (EPA) in the United States, as well as regulations issued by Transport Canada and Health Canada, and EU tire labeling in Europe, there is an unmet demand for further improvements in the fuel efficiency of tires. One way to determine fuel efficiency is to examine the rolling resistance of the rubber composition, which can be determined by various mechanical properties of the rubber composition. In simple terms, the lower the rolling resistance of the rubber composition, the more fuel efficient the tire.

[0003] Generally, it is known in the art that various properties, such as wet traction and rolling resistance, can be improved by adding silica or sulfur-containing organosilane coupling agents to tire tread rubber compositions. Therefore, the Japanese patent No. 50-88150 shows that by adding silane compounds containing silica and sulfur atoms to the rubber mixture, this treatment of winter tires gives the tire tread improved skid resistance. Similarly, the European patent No. EP 0299074 suggests the use of functionalized alkoxysilanes as reinforcing fillers in rubber compositions containing silica. Similarly, the U.S. Patent No. 5,227,425 (the disclosure of which is incorporated herein by reference in its entirety) discloses a tire tread composition, wherein the rubber component is a copolymer of a conjugated diene and a vinyl aromatic compound prepared in a solution, and wherein the carbon black filler is partially or completely replaced by silica and a silane coupling agent, and the silane coupling agent is added separately from the polymer during the mixing process.

[0004] However, these rubber compounds cannot withstand the loads required of heavy vehicles, such as commercial medium-duty trucks weighing more than 13,000 lb. or heavy-duty trucks weighing more than 26,000 lb. These rubber compounds are better suited for smaller tires, such as those used on passenger cars and light trucks.

[0005] Attempts have been made to address the problem of providing a high load-bearing tread composition having enhanced natural rubber stress-strain properties including silica in order to provide an energy-efficient tread for tires for applications such as trucks or buses. One such attempt is provided by U.S. Patent Application Publication No. US2020 / 0140661 A1 (now U.S. Patent No. 11,267,955), which discloses and claims a rubber compound containing natural rubber, a reinforcing filler (e.g., silica) that is reactive with a special silane coupling agent (e.g., hexamethoxymethylmelamine (HMMM) functionalized silane), and a secondary grid based on resorcinol or resorcinol-formaldehyde resin. In the patent, it is noteworthy that phloroglucinol is considered to be a potential active hydrogen-containing compound. However, as described below, phloroglucinol is not a phloroglucinol resin. Furthermore, it is noteworthy that the patent claims a hexamethoxymethylmelamine functionalized silane that reacts with a reinforcing filler. The novelty of the patent is believed to reside in this and it does not claim the use of hexamethoxymethylmelamine (HMMM) independently and separately from the silane.

[0006] On the other hand, resorcinol-formaldehyde resins, also known as RF resins or resorcinol resins, are reaction products of resorcinol and formaldehyde and have been widely used in various applications including rubber compounding. In rubber compound formulations, solid RF resins have long been used to enhance rubber properties, such as the adhesion between rubber and reinforcement materials and the dynamic properties of products such as tires, belts and hose products.

[0007] The problem with these resins is that resorcinol resins typically contain 10% to 20% unreacted or free resorcinol. The amount of free resorcinol can be a critical factor in balancing important properties, and the presence of free resorcinol can be problematic. For example, free resorcinol can volatilize during the rubber compounding process. This volatilization is often referred to as fuming, which creates additional problems in the rubber compounding process. In addition, the presence of free resorcinol increases the hygroscopicity of the resorcinol resin, which creates storage and handling problems.

[0008] Additionally, formaldehyde has been used for many years in the production of resorcinol-formaldehyde resins. Given its widespread use, toxicity, and volatility, formaldehyde presents potential health and environmental concerns. In 2011, the U.S. National Toxicology Program classified formaldehyde as a known human carcinogen. As a result, rubber compositions containing resorcinol or resorcinol-formaldehyde resin compounds are currently not acceptable for new tire manufacturers.

[0009] WIPO patent publication number WO2021 / 141934 provides for the use of phloroglucinol resins instead of resorcinol or resorcinol-formaldehyde resins, but only if no silane additives are used. That is, like many of the other patents cited above, these resins are only suitable for rubber compositions used in light vehicle tires because no silane additives are used in these patents or tires.

[0010] Therefore, there is a need to develop a high load-bearing rubber compound having enhanced stress-strain properties of natural rubber and fuel efficiency of silicone-based tread for heavy-duty vehicle (e.g., medium to heavy truck and bus) tire applications. Summary of the invention

[0011] To develop fuel-efficient heavy truck and bus tires without resorcinol or formaldehyde, the inventors developed rubber compound formulations consisting of natural rubber, silica, a specialty silane coupling agent, hexamethoxymethylmelamine (HMMM) (independent of the silane coupling agent), and phloroglucinol resin. Surprisingly and unexpectedly, these rubber formulations exhibited better fuel efficiency and durability than compounds containing resorcinol. The present invention provides a better natural rubber-silica tread compound for trucks and buses without any resorcinol or formaldehyde.

[0012] At least one aspect of the present invention can be embodied in a rubber composition comprising: (a) a rubber polymer or polymer blend; (b) at least one organosilane coupling agent; (c) at least one reinforcing filler reactive with at least one organosilane coupling agent; (d) at least one methylene donor compound; (e) at least one phloroglucinol resin; and (f) at least one sulfur donating compound. In various embodiments, the rubber composition includes the above ingredients, wherein the rubber component (a) is about 25 to about 95 weight % based on the total weight of the rubber composition; the organosilane coupling agent (b) is 0.05 to 30 parts of the organosilane coupling agent (b) per 100 parts of the rubber polymer; the reinforcing filler (c) reacted with the organosilane coupling agent (b) is 1 to 150 parts of the reinforcing filler per 100 parts of the rubber polymer; the methylene donor compound (d) is 0.1 to 30 parts of the methylene donor compound per 100 parts of the rubber polymer; the phloroglucinol resin (e) is 0.1 to 10 parts of the phloroglucinol resin per 100 parts of the rubber polymer; and the sulfur-donating compound (f) is 0.1 to 5 parts of the sulfur-donating compound per 100 parts of the rubber compound.

[0013] In one or more embodiments, the rubber polymer (a) can be selected from natural rubber (NR), synthetic polyisoprene (IR), polybutadiene (BR), various copolymers of butadiene, copolymers of isoprene, solution styrene-butadiene rubber (SSBR), emulsion styrene-butadiene rubber (ESBR), ethylene-propylene terpolymer (EPDM), acrylonitrile-butadiene rubber (NBR), and functionalized rubber modified by at least one alkoxysilane group, tin-containing group, amino group, hydroxyl group, carboxylic acid group, polysiloxane group, epoxy group or phthalocyanine group. In other more specific embodiments, the rubber polymer includes natural rubber or a mixture of natural rubber and butadiene rubber.

[0014] In these and other embodiments, the reinforcing filler (b) may be selected from fibers, particles or platelet structures comprising metalloid oxides or metal oxides having surface hydroxyl groups. In the same or other embodiments, the reinforcing filler (b) comprises precipitated silica.

[0015] In these and other embodiments, the methylene donor compound (d) may be selected from polyisocyanates, polyisocyanurates, epoxy resins, amino resins, and polyurethanes. In these and other embodiments, an amino resin may be included, which is selected from: 1,1,3,3-tetramethoxymethyl urea, 1,3,3-trimethoxymethyl urea, 1,3-bismethoxymethyl urea, 1,1-bismethoxymethyl urea, 1,1,3,3-tetraethoxymethyl urea, 1,3,3-triethoxymethyl urea, 1,3-bisethoxymethyl urea, 1,1-bisethoxymethyl urea, 1,1,3,3-tetrapropoxymethyl urea, 1,3,3-tripropoxymethyl urea, 1,3-bispropoxymethyl urea, 1,1-bispropoxymethyl urea, 1,1,3,3-tetrabutoxymethyl urea, 1,3,3-tripropoxymethyl urea, 1,3 ... Oxymethyl urea, 1,1,3,3-tetraphenoxymethyl urea, N-(1,3,3-triethoxymethylureidomethyl)-1,1,33-tetraethoxymethyl urea, N,N′-bis-(1,1,3-triethoxymethylureidomethyl)-1,3-bisethoxymethyl urea, N,N′-bis-(1,1,3-triethoxymethylureidomethoxymethyl)-1,3-bisethoxymethyl urea, N,N,N′,N′,N″,N″-hexamethoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″-pentamethoxymethyl-[1, 3,5]triazine-2,4,6-triamine, N,N,N′,N″-tetramethoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″,N″-hexaethoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″-pentaethoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N″-tetraethoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″,N″-hexapropoxymethyl-[1,3,5]triazine -2,4,6-triamine, N,N,N′,N′,N″-pentapropoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N″-tetrapropoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″,N″-hexaphenoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″-pentaphenoxymethyl-[1,3,5]triazine-2,4,6-triamine and N,N,N′,N″-tetraphenoxymethyl-[1,3,5]triazine-2,4,6-triamine.

[0016] In these and other embodiments, the phloroglucinol resin (e) has the structure shown in Formula (I):

[0017]

[0018] Among them, R 1, R 2 and R 3 At least one of them combines with the second phloroglucinol unit to form a disubstituted methylene bridge, wherein R 1 , R 2 and R 3 The second one in is a hydrogen atom, or it combines with the third phloroglucinol unit to form another disubstituted methylene bridge, wherein R 1 , R 2 and R 3 The third one in is a hydrogen atom. More specifically, the phloroglucinol resin can be a solid. It should be understood that in one or more embodiments, the phloroglucinol resin can have a chemical structure as described above, and therefore can have an isopropyl bridge, which has a chemical structure of a disubstituted methylene bridge. In other embodiments, the phloroglucinol resin can have a chemical structure as described above, and therefore can have a chemical structure of 2,2 disubstituted butane bridges as disubstituted methylene bridges. In some further embodiments, the phloroglucinol resin can have a chemical structure as described above, and therefore can have a chemical structure of 2,2 disubstituted, 4-methylpentane bridges as disubstituted methylene bridges.

[0019] It should also be understood that the solid phloroglucinol resin used in the rubber composition can be the reaction product of phloroglucinol and a ketone in the presence of an acidic catalyst. The ketone can be selected from acetone, methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK).

[0020] In general, it will be appreciated that the sulfur donating compound (f) may be sulfur.

[0021] One or more other aspects of the present invention are embodied in a method for preparing the rubber composition.

[0022] Other aspects of the present invention are embodied in a cured rubber composition prepared from the above rubber composition. It should be understood that other aspects of the present invention can be obtained by an article (eg, a tire component) comprising the cured rubber composition. DETAILED DESCRIPTION

[0023] Truck tires and other heavy vehicle tires include an expandable structure made of multiple shrinkable rubber belts and composite materials. For example, the layer above the inner liner consists of fine textile fiber cords bonded into rubber and is called the carcass or casing. Carcass and casing are interchangeable terms. Many tire carcasses are made of one or two carcass plies. The tire carcass can contain steel, polyester, nylon or rayon cord fabrics within the carcass rubber compound. During the tire manufacturing process, the belt system can be arranged on top of the carcass portion (radially outward). The tread plate or crown portion can be arranged on top of the belt system and / or the carcass (radially outward). The tread portion contacts the road and is configured to enhance the performance and durability of the tire. Key characteristics include handling, traction, rolling resistance and wear resistance.

[0024] In the specification and claims herein, the following terms and expressions are to be understood as indicated.

[0025] Except in the working examples or where otherwise indicated, all numbers indicating amounts of materials, reaction conditions, durations, quantitative properties of materials, etc., described in the specification and claims are to be understood as being modified in all instances by the term "about". In addition, when a number in a table is provided in the claims, it is to be understood that when most or many other numbers in the same table for the same attribute, quantity, etc. are lower than the number provided, the number will mean "or less". Conversely, when a number in a table is provided in the claims, it is to be understood that when most or many other numbers in the same table for the same attribute, quantity, etc. are higher than the number provided, the number will mean "or more".

[0026] Unless otherwise specified herein or clearly contradictory to the context or unless a specific order is required, all methods described herein may be performed in any suitable order. The use of any and all examples or exemplary language (e.g., "such as") provided herein is intended only to better illustrate the present invention and, unless otherwise stated, is not intended to limit the scope of the present invention.

[0027] No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0028] The term "for instance" has the same meaning as "for example".

[0029] It should be understood that any numerical range recited herein includes all sub-ranges within that range and any combination of the various endpoints of such ranges or sub-ranges.

[0030] As used herein, integer values ​​of stoichiometric subscripts refer to molecular species, while non-integer values ​​of stoichiometric subscripts refer to mixtures of molecular species based on molecular weight averages, number averages, or mole fractions.

[0031] In the following description, unless otherwise specified, all weight % are based on the total weight % of organic materials, and all ranges given herein include all subranges therebetween and any combination of ranges and / or subranges therebetween.

[0032] As used herein, "rubber polymer" is an organic polymer containing at least two carbon-carbon double bonds and a main chain comprising one or more chains of carbon atoms or a mixture thereof. In one embodiment of the present invention, the rubber polymer may be at least one selected from a diene elastomer and a rubber. The rubber polymer may be any one known in the art and has been described in many references, two examples of which are incorporated herein by reference.

[0033] The term "rubber polymer" does not exclude that some parts of the polymer may be temporarily or permanently in a partially or completely crystalline state. The terms used in this specification are as similar as possible to those appearing in Vanderbilt Rubber Handbook, RF Ohm, ed., RT Vanderbilt Company, Inc., Norwalk, CT, 1990; and Manual For The Rubber Industry, T. Kempermann, S. Koch, J. Sumner, ed., Bayer AG, Leverkusen, Germany, 1993.

[0034] The term "primary lattice" refers to the rubber polymer lattice that has been crosslinked by vulcanization with a crosslinking agent in a cure package.

[0035] The term interpenetrating network refers to the fact that the polymeric components of the rubber compound do not covalently interact with the primary network within the compound.

[0036] Some representative non-limiting examples of suitable rubber polymers (i.e., the rubber component of the composition) include those selected from natural rubber (NR), synthetic polyisoprene (IR), polybutadiene (BR), various butadiene copolymers, various isoprene copolymers, solution styrene-butadiene rubber (SSBR), emulsion styrene-butadiene rubber (ESBR), ethylene-propylene terpolymer (EPDM), acrylonitrile-butadiene rubber (NBR), and combinations thereof. It is understood that natural rubber (NR) includes rubber from various natural plant sources, including but not limited to rubber trees, dandelions, guayule, etc.

[0037] Suitable monomers for preparing the rubber polymer herein may be selected from: conjugated dienes (such as the non-limiting examples of isoprene and 1,3-butadiene); and suitable vinyl aromatic compounds (such as the non-limiting examples of styrene and alpha methyl styrene) and combinations thereof. The rubber polymer may be a sulfur cured rubber. The diene-based elastomer or rubber may be selected as at least one of cis-1,4-polyisoprene rubbers, including natural rubber and synthetic polyisoprene rubbers, more specifically natural rubber, styrene / butadiene copolymer rubber prepared by emulsion polymerization, styrene / butadiene rubber prepared by organic solution polymerization, 3,4-polyisoprene rubber, isoprene / butadiene rubber, styrene / isoprene / butadiene terpolymer rubber, cis-1,4-polybutadiene, medium vinyl polybutadiene rubber (35-50% vinyl), high vinyl polybutadiene rubber (50-75% vinyl), styrene / isoprene copolymer, styrene / butadiene / acrylonitrile terpolymer rubber prepared by emulsion polymerization, and butadiene / acrylonitrile copolymer rubber. Emulsion polymerization derived styrene / butadiene rubbers (ESBRs) are also contemplated for use as diene-based rubbers for use herein, including ESBRs having relatively conventional styrene contents (i.e., 20% to 28% bound styrene), or, for certain applications, ESBRs having moderate to relatively high bound styrene contents (i.e., 28% to 45% bound styrene contents). Emulsion polymerization prepared styrene / butadiene / acrylonitrile terpolymer rubbers containing 2 to 40% by weight bound acrylonitrile are also contemplated for use as diene-based rubbers for use herein.

[0038] The rubber polymer can also be a functionalized rubber. Functionalized rubber is a rubber modified by at least one functional group containing atoms other than carbon or hydrogen. The functional group is generally an alkoxysilane group, a tin-containing group, an amino group, a hydroxyl group, a carboxylic acid group, a polysiloxane group, an epoxy group, etc., or a combination of these functional groups. In the process of preparing synthetic rubber, the functional group can be introduced into the rubber polymer by copolymerizing the monomer used to make the rubber with the monomer, initiator or termination unit containing the functional group.

[0039] Alternatively, the rubber polymer may be modified with functional groups by grafting the functional groups onto an already formed rubber polymer.

[0040] Functionalized rubber polymers can be used in combination with other non-functionalized rubber polymers. The mixture can contain at least about 5 to about 95 parts per hundred parts of rubber of at least one styrene-butadiene rubber, the rubber being functionalized with at least one group selected from phthalocyanine groups, tin-containing groups, hydroxyl groups, epoxy groups, carboxylate groups, amino groups, alkoxysilane groups, and sulfur groups, wherein the styrene content is 0 to about 12 weight percent, and about 5 to about 95 parts per hundred parts of rubber contain at least one additional rubber polymer. According to DSC testing, the glass transition temperature (Tg) of the functionalized rubber polymer (rubber) in the uncured state is generally -120 to -10°C.

[0041] In another embodiment of the present invention, the rubber polymer can be a diene polymer functionalized or modified by an alkoxysilane derivative. Styrene-butadiene rubber prepared by silane functionalized organic solution polymerization and 1,4-polybutadiene rubber prepared by silane functionalized organic solution polymerization can be used. These rubber compositions are known; see, for example, U.S. Pat. No. 5,821,290, the entire contents of which are incorporated herein by reference.

[0042] In another embodiment of the invention, the rubber polymer is a diene polymer functionalized or modified with a tin derivative. Tin-coupled copolymers of styrene and butadiene can be prepared, for example, by introducing a tin coupling agent in an organic solvent solution during the copolymerization of styrene and 1,3-butadiene monomers, typically at or near the end of the polymerization reaction. Such tin-coupled styrene-butadiene rubbers are well known to those skilled in the art; see, for example, U.S. Patent No. 5,268,439, the entire contents of which are incorporated herein by reference. In practice, at least about 50%, preferably about 60% to about 85%, of the tin is bound to the butadiene units of the styrene-butadiene rubber to form tin-dienyl bonds.

[0043] The properties of natural rubber (NR) are particularly useful in the manufacture of heavy vehicle tires, bus tires and truck tires. One of the important reasons is that cis-1,4-polyisoprene content is high in natural rubber, molecular weight is large and has the ability of strain induced crystallization. In one embodiment of the invention, the rubber polymer includes natural rubber, or a mixture of natural rubber and synthetic rubber. Preferably, when the rubber polymer is a rubber mixture, the rubber formulation should include at least about 10% by weight of natural rubber, preferably about 30% by weight of natural rubber, more preferably at least about 50% by weight of natural rubber, even more preferably at least about 70% by weight of natural rubber.

[0044] The uncured rubber composition preferably contains reinforcing fillers. The reinforcing filler should be a material with a modulus higher than that of the rubber polymer of the rubber composition, and should be able to absorb stress when the cured rubber composition is subjected to strain. The reinforcing filler can be a material that reacts with an organosilane coupling agent and can include fibers, particles and sheet structures. They can be composed of inorganic minerals, silicates, silica, clay, ceramics and diatomaceous earth. The reinforcing filler that reacts with the organosilane coupling agent can be a discrete particle or a particle group in the form of an aggregate or agglomerate. The organosilane coupling agent can react with the filler surface. Granular precipitated silica can be used as a reinforcing filler that reacts with an organosilane coupling agent, particularly when the silica has a reactive surface silanol. The silica can be provided in a hydrated form or converted to a hydrated form by reaction with water. The amount of reinforcing filler can be 1 to 150 parts of reinforcing filler per 100 parts of rubber polymer, more specifically, 25 to 90 parts of reinforcing filler per 100 parts of rubber polymer, and more specifically, 40 to 80 parts of reinforcing filler per 100 parts of rubber polymer.

[0045] Representative, non-limiting examples of reinforcing fillers that react with the organosilane coupling agent include at least one metalloid oxide or metal oxide such as fumed silica, precipitated silica, titania, aluminosilicates, alumina, and siliceous materials including clay and talc, and combinations thereof.

[0046] In one or more embodiments of the present invention, the reinforcing filler can be silica used alone or in combination with one or more other fillers (e.g., organic and / or inorganic fillers that do not react with organosilane coupling agents). A representative, non-limiting example is a combination of silica and carbon black, such as a reinforcing filler for various rubber products, including the non-limiting example of tire treads. Alumina can be used alone or in combination with silica. The term "alumina" herein refers to aluminum oxide or Al2O3. The use of alumina in rubber compositions is known; see, for example, U.S. Patent No. 5,116,886 and EP 631982, both of which are incorporated herein by reference in their entirety.

[0047] Reinforcing fillers reactive with organosilane coupling agents can serve as carriers for organosilane coupling agents. Other fillers that can be used as carriers do not react with organosilane coupling agents. The non-reactive nature of the filler is demonstrated by the ability to extract the organosilane coupling agent in greater than 50% of the loaded silane using an organic solvent. The extraction procedure is described in U.S. Patent Publication No. 6,005,027, the entire contents of which are incorporated herein by reference. Representative materials for non-reactive carriers include, but are not limited to, porous organic polymers and carbon black. The amount of organosilane coupling agent that can be loaded on the carrier is preferably 0.1% to 70%, more preferably 10% to 50%, of the total weight of the carrier and the organosilane coupling agent.

[0048] In one non-limiting embodiment of the present invention, other fillers that can be mixed with reinforcing fillers reactive with organosilane coupling agents are substantially inert to the organosilane coupling agents mixed therewith, such as carbon black or organic polymers. In another embodiment, at least two reinforcing fillers reactive with organosilane coupling agents can be mixed together and can react therewith. Reinforcing fillers having pseudo-metal hydroxyl surface functional groups, such as silica and other siliceous particles having surface silanol functional groups, can be used in combination with reinforcing fillers containing metal hydroxyl surface functional groups, such as alumina and other siliceous fillers.

[0049] In one embodiment of the present invention, precipitated silica is used as a reinforcing filler for reaction with an organosilane coupling agent. In a preferred embodiment of the present invention, the silica filler is characterized in that its Brunauer, Emmett and Teller (BET) surface area (measured using nitrogen) is from about 40 to about 600 m 2 / g, preferably about 50 to about 300 m 2 / g, more preferably about 100 to about 220 m 2 / g. The BET method for measuring surface area described in the Journal of the American Chemical Society, Vol. 60, p. 304 (1930) is used herein. In another preferred embodiment, the typical characteristic of silica is that the absorption value of dibutyl phthalate (DBP) is about 100 to about 350, preferably about 150 to about 300, and more preferably about 200 to about 250. In other embodiments, the reinforcing filler reacted with the organic silane coupling agent can be alumina and aluminosilicate fillers, and has a molecular weight of about 80 to about 220 m 2 The CTAB surface area is the external surface area measured by cetyltrimethylammonium bromide at a pH of about 9; the measurement method is described in ASTM D 3849.

[0050] Mercury pore surface area is the specific surface area determined by mercury porosimetry. In this technique, mercury penetrates into the pores of the sample after heat treatment to remove volatiles. In a more specific embodiment, conditions are set to remove volatiles within 2 hours at 105°C and ambient atmospheric pressure using 100 mg of sample, and a measurement range from ambient pressure to 2000 bar pressure is used. Such evaluations can be made according to the method described by Winslow et al. in ASTM Bulletin 39 (1959) or in accordance with DIN 66133; for such evaluations, a CARLO-ERBA Porosimeter 2000 can be used. Useful reinforcing fillers that can react with silane include silica, which has an average mercury pore specific surface area of ​​about 100 to about 300 m 2 / g, preferably about 150 to about 275m 2 / g, more preferably about 200 to about 250 m 2 / g.

[0051] For reinforcing fillers that can react with an organosilane coupling agent, suitable pore size distributions include non-limiting examples of silica, alumina, and aluminosilicates, which are considered herein to have pores with diameters less than 10 nm or less, according to such mercury porosity evaluation; pores with diameters of 10 to 100 nm account for about 60% to about 90%; pores with diameters of 100 to 1000 nm account for about 10% to about 30%; pores with diameters greater than 1000 nm account for about 5% to about 20%. These reinforcing fillers can generally be expected to have an average final particle size in the range of about 0.005 to about 0.075 mm, preferably about 0.01 to about 0.05 mm, as determined by electron microscopy, although the average size of the particles can be smaller or larger. Various commercially available silicas may be used in the present invention, such as those available from PPG Industries under the HI-SIL trademark, particularly HI-SIL 210 and 243; silicas available from Solvay, such as ZEOSIL 1165MP; silicas available from Evonik, such as VN2 and VN3, and the like, and silicas available from Huber, such as HUBERSIL 8745.

[0052] In one embodiment of the invention, the filler may include a reinforcing filler that can react with an organosilane coupling agent, and the amount thereof is about 15 to about 95 weight % of precipitated silica, alumina and / or aluminosilicate, preferably silica, and correspondingly, about 5 to about 85 weight % of carbon black having a CTAB value of about 80 to about 150, more preferably, the filler may include about 60 to about 95 weight % of the silica, alumina and / or aluminosilicate, preferably silica, and correspondingly, about 40 to about 50 weight % of carbon black. The precipitated silica, alumina and / or aluminosilicate fillers and the carbon black may be premixed or mixed together during the manufacture of the vulcanized rubber. When used, 0.5 to 10 parts of carbon black may be added per 100 parts of rubber polymer.

[0053] The tread portion of a tire is typically formulated with carbon black filler. Carbon black provides excellent wear resistance to the tread, resulting in higher mileage and longer service life for the tire. When silica is used as a filler, the dispersion of silica throughout the rubber matrix can be reversed to high friction silica-silica and rubber-silica interactions. This friction can affect tire properties such as rolling resistance. Adding conventional silanes to tire formulations can reduce rolling resistance by limiting internal friction of silica-silica interactions and fixing polymer chains to the silica surface. However, without being bound by theory, it is believed that silanes can increase the trans content of natural rubber by binding to rubber chains through sulfur, as discussed in JI Cuneen, Rubber Chemistry and Technology, Vol. 33, p. 445, 1960; and JI Cuneen and FW Shipley, Journal of Polymer Science, Vol. 36, p. 77, 1959. This may have an adverse effect on properties such as wear resistance. Furthermore, severely restricting the chain mobility may affect the ability of natural rubber to undergo strain-induced crystallization and compromise the abrasion and tear resistance.

[0054] Conventional silanes react directly with polymer chains and degrade key properties of the primary rubber network. Standard amino resin-resorcinol systems can reinforce the primary polymer network through an interpenetrating network, but may produce irreversible strain and lead to degradation of key properties. Without being bound by theory, it is believed that the organosilane reacts with the HMMM and phloroglucinol resin to form an interpenetrating network that enhances load transfer from one filler to another and reduces friction between filler aggregates. The concentration of the thermoset interpenetrating network at the filler interface attracts the thermoset material where the strain is minimum.

[0055] Rolling resistance can be reduced by hydrophobic treatment of silica. Increasing the effective filler volume improves wear and tear resistance. In addition, the secondary polymer grid increases the strength and stiffness of the tread under static and dynamic deformation.

[0056] This load-bearing path-enhancing interpenetrating network polymerization is believed to grow from the surface of reinforcing fillers (especially silica surfaces) that react with organosilane coupling agents. These organosilane coupling agents can act as initiators or co-initiators during rubber mixing and / or curing. The resulting reinforcing interpenetrating network may create additional physical and chemical chain entanglement points for the rubber phase directly surrounding the filler. These entanglements and the resulting interpenetrating polymer network and silica are believed to form a hierarchical structure with a modulus gradient that can be used to transfer loads from rubber polymer chains to silica during static and dynamic deformation, thereby enhancing tear and abrasion resistance and reducing wear. The interpenetrating polymer network polymerization occurring on the filler surface can form a grid structure on the filler surface, increasing the effective volume of the filler. This grid structure and effective filler volume create additional reinforcement, which also helps to improve wear resistance.

[0057] Without being bound by theory, it is believed that the polymer network is formed by an enhanced interpenetrating polymer network methylene donor compound and a phloroglucinol resin. As will be appreciated by those skilled in the art, an interpenetrating network may also be referred to as a secondary network. Without being bound by theory, a secondary network refers to two discrete polymer networks that are indistinguishable on a macroscopic scale. The phloroglucinol resin that forms the load-bearing path enhanced interpenetrating network includes, but is not limited to, phloroglucinol connected by disubstituted methylene bonds.

[0058] In one embodiment of the present invention, the methylene donor compound is an amino resin. The amino resin can be a resin formed by reacting an -NH-containing compound with formaldehyde and an alcohol. More preferably, the amino resin is derived from 2,4,6-triamino-1,3,5-triazine, benzoguanamine, urea, glycoluril and poly(meth)acrylamide.

[0059] The methylene donor compound may be used in an amount of 0.1 to 30 parts of methylene donor compound per 100 parts of rubber polymer, more specifically 0.2 to 15 parts of methylene donor compound per 100 parts of rubber polymer, even more specifically 0.3 to 10 parts of methylene donor compound per 100 parts of rubber polymer.

[0060] Representative and non-limiting examples of methylene donor compounds are 1,1,3,3-tetramethoxymethyl urea, 1,3,3-trimethoxymethyl urea, 1,3-bismethoxymethyl urea, 1,1-bismethoxymethyl urea, 1,1,3,3-tetraethoxymethyl urea, 1,3,3-triethoxymethyl urea, 1,3-bisethoxymethyl urea, 1,1-bisethoxymethyl urea, 1,1,3,3-tetrapropoxymethyl urea, 1,3,3-tripropoxymethyl urea, 1,3-bispropoxymethyl urea, 1,1-bispropoxymethyl urea, 1,1,3,3-tetrabutoxymethyl urea, 1,1,3,3-tetraphenoxymethyl urea, N-(1,3,3-triethoxymethylureamethyl)-1,1,3,3-tetraethoxymethyl urea, N,N′-bis-(1,1,3-triethoxymethylureidomethyl)-1,3-bisethoxymethylurea, N,N′-bis-(1,1,3-triethoxymethylureidomethoxymethyl)-1,3-bisethoxymethylurea, N,N,N′,N′,N″,N″-hexamethoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″-pentamethoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N″-tetramethoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″,N″-hexaethoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′, N′,N″-pentaethoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N″-tetraethoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″,N″-hexapropoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″-pentapropoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N″-tetrapropoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″-hexaphenoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″-pentaphenoxymethyl-[ 1,3,5]triazine-2,4,6-triamine and N,N,N′,N″-tetraphenyloxymethyl-[1,3,5]triazine-2,4,6-triamine, 1,3,4,6-tetra-methoxymethyl-tetrahydro-imidazo[4,5-d]imidazole-2,5-dione, 1,3,4,6-tetra-ethoxymethyl-tetrahydro-imidazo[4,5-J]imidazole-2,5-dione, 1,3,4,6-tetra-propoxymethyl-tetrahydro-imidazo[4,5-d]imidazole-2,5-dione, 1,3,4,6-tetra-phenoxymethyl-tetrahydro-imidazo[4,5-d]imidazole-2,5-dione, 1,3,4,6-tris-ethoxymethyl-tetrahydro-imidazo[4,5-d]imidazole-2,5-dione, 1,4-Bis-ethoxymethyl-tetrahydro-imidazo[4,5-d]imidazole-2,5-dione, 1,3,4-tris-methoxymethyl-tetrahydro-imidazo[4,5-d]imidazole-2,5-dione and 1,3,4-tris-phenoxymethyl-tetrahydro-imidazo[4,5-d]imidazole-2,5-dione.

[0061] Methylene donor compounds are commercially available. For example, amino resins are available from PERFERE, formally from INEOS Melamine GmbH, under the trade name 747ULF, 755, 757, 764, CE 8824ULF and UF134 / 60B purchase.

[0062] In one example, the organosilane coupling agent has the general formula (Ia):

[0063] (R 2 O)a(R 3 )3 -a Si(R 4 XH)

[0064] Each R 2 is independently hydrogen, an alkyl group having 1 to 10 carbon atoms and optionally having at least one oxygen atom, a cycloalkyl group having 3 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably an ethyl group; each R 3 R is independently an alkyl group having 1 to 3 carbon atoms or a phenyl group; 4 is an alkylene group having 1 to 10 carbon atoms and optionally having at least one oxygen atom, a cycloalkylene group having 3 to 10 carbon atoms, an alkenylene group having 2 to 10 carbon atoms, an arylene group having 6 to 12 carbon atoms, an aralkylene group having 7 to 14 carbon atoms, more preferably an alkylene group having 1 to 6 carbon atoms, even more preferably a propylene group; X is one or more sulfur atoms, preferably 2 to 10 on average, even more preferably 2 to 4 on average.

[0065] Representative non-limiting examples of silanes containing a functional group of formula (Ia) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltripropoxysilane, 3-mercaptopropyldimethoxyethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropyldimethylethoxysilane, mercaptomethyltriethoxysilane, 4-mercapto-3,3-dimethylbutyltriethoxysilane, 3-mercaptopropylethoxy-[1,3,2]dioxasilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxy ... triethoxysilane, 3-ureapropyltriethoxysilane, 3-ureapropyltriethoxysilane, 3-ureapropyltrimethoxysilane, and mixtures thereof.

[0066] The silane coupling agent in formula (Ia) may be used in an amount of 0.05 to 30 parts of mercaptosilane coupling agent per 100 parts of rubber polymer, more specifically 0.5 to 15 parts of mercaptosilane coupling agent per 100 parts of rubber polymer, even more specifically 1 to 10 parts of mercaptosilane coupling agent per 100 parts of rubber polymer.

[0067] The organosilane of formula (Ia) can be obtained commercially. For example, mercaptosilane coupling agents can be purchased from Momentive Performance Materials, Inc. under the trade names Si263, Usi-5301, Silquest A-189, Z-6062, KBM-803. MTMO, GF 70 and S810.

[0068] In another example, the organic silane coupling agent is a silane having the following general formula (Ib):

[0069] (R 2 O) a R 3 3-a Si(R 4 )X 1 R 4 Si(R 3 3-a (R 2 O) a )

[0070] Each R 2is independently hydrogen, an alkyl group having 1 to 10 carbon atoms and optionally having at least one oxygen atom, a cycloalkyl group having 3 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably an ethyl group; each R 3 R is independently an alkyl group having 1 to 3 carbon atoms or a phenyl group; 4 is an alkylene group having 1 to 10 carbon atoms and optionally having at least one oxygen atom, a cycloalkylene group having 3 to 10 carbon atoms, an alkenylene group having 2 to 10 carbon atoms, an arylene group having 6 to 12 carbon atoms, an aralkylene group having 7 to 14 carbon atoms, more preferably an alkylene group having 1 to 6 carbon atoms, even more preferably a propylene group; X is one or more sulfur atoms, preferably 2 to 10 on average, even more preferably 2 to 4 on average.

[0071] Representative non-limiting examples of silanes containing a functional group represented by formula (Ib) include bis(tripropoxysilylpropyl)tetrasulfide, bis(triethoxysilylpropyl)tetrasulfide, bis(trimethoxysilylethyl)tetrasulfide, bis(trimethoxymethyl)tetrasulfide, bis(tripropoxysilylpropyl)disulfane, bis(triethoxysilylethyl)tetrasulfide, bis(triethoxysilylmethyl)tetrasulfide, bis(3-triethoxysilylpropyl)disulfane, bis[3-(triethoxysilyl)propyl]- disulfide, bis[3-(triethoxysilyl)propyl]persulfide, 3,3'-bis-(triethoxysilylpropyl)disulfide, bis[3-(triethoxysilyl)propyl]perdisulfide, bis(triethoxysilyl)-4,5-dithiooctane, bis(tripropoxysilylpropyl)disulfide, bis(triethoxysilylpropyl)disulfide, bis(trimethoxysilylethyl)disulfide, bis(triethoxysilylethyl)disulfide, bis(triethoxysilylmethyl)disulfide.

[0072] The silane coupling agent in formula (Ib) may be used in an amount of 0.05 to 30 parts of organosilane coupling agent per 100 parts of rubber polymer, more specifically 0.5 to 15 parts of organosilane coupling agent per 100 parts of rubber polymer, even more specifically 1 to 10 parts of organosilane coupling agent per 100 parts of rubber polymer.

[0073] An organosilane of formula (Ib) wherein X 1The average represents four sulfurs and can be obtained commercially. For example, Si69 coupling agent can be purchased from Evonik. Crosile 69 TESPT can be purchased from Guangzhou Ecopower. Z6940 can be purchased from Owen Corning. A-1289 can be purchased from Momentive Performance Materials. KBE-846 can be purchased from Shin-Etsu. In addition, the organosilane of molecular formula (Ib) can be purchased under the trade names Si75, HP1589, JH-S75, TESPD, where X 1 Represents an average of two sulfurs.

[0074] In another embodiment, the organosilane is covalently attached to the hydrogen-containing compound.

[0075] The rubber composition of the present invention may also include a phloroglucinol resin, which may be solid under standard conditions. A solid phloroglucinol resin comprises a plurality of phloroglucinol units generally defined by formula (II):

[0076]

[0077] Among them, R 1 , R 2 and R 3 At least one of them is combined with the second phloroglucinol unit to form a disubstituted methylene bridge, wherein R 1 , R 2 and R 3 The second one in is a hydrogen atom, or it combines with the third phloroglucinol unit to form another disubstituted methylene bridge, where R 1 , R 2 and R 3 The third one in formula (II) is intended to represent R 1 , R 2 or R 3 The disubstituted methylene bridge of can be bonded to the 2, 4 or 6 position of the aromatic ring. 1 , R 2 or R 3 The hydrogen atoms are also located at the 2, 4 or 6 positions. It will be appreciated by those skilled in the art that any carbon atom in the aromatic ring that is not bonded to a hydroxyl group may be bonded to R 1 , R 2 or R 3 bond, and will include hydrogen atoms or be part of a disubstituted methylene bridge.

[0078] Generally, the disubstituted methylene bridge is connected to at least two C1 to C10 alkyl groups extending from the methylene bridge. In another embodiment, the methylene bridge includes at least two C1 to C5 alkyl groups extending therefrom. In yet another embodiment, the methylene bridge includes at least two C1 to C4 alkyl groups extending therefrom. In yet another embodiment, the methylene bridge includes at least two C1 to C3 alkyl groups extending therefrom. In yet another embodiment, the methylene bridge includes at least two C1 to C2 alkyl groups extending therefrom.

[0079] More specifically, the phloroglucinol resin of the present invention can be described as shown in formula (III).

[0080]

[0081] The R 1 has been replaced by a disubstituted methylene bridge as shown at position 2, and R 3 has been replaced by 5 substituted. 3 and R on the right 1 It may also be a disubstituted methylene bridge as shown herein, or it may be a hydrogen atom, and in this embodiment R 2 It can be a hydrogen atom. 4 and R 5 In one embodiment, R 4 and R 5 In another embodiment, R 4 It can be ethyl, R 5 It can be methyl, wherein the disubstituted methylene bridge formed is a 2,2 disubstituted butane bridge. In another embodiment, R 4 It can be isopropyl and R 5 It may be methyl, wherein the disubstituted methylene bridge formed is a 2,2 disubstituted 4-methylpentane bridge.

[0082] The resin is distributed in dimer, trimer, tetramer, pentamer and pentamer or more, and can be used with resin when the monomer content is less than 40%. The amount of phloroglucinol resin can be 0.1 to 15 parts of phloroglucinol resin per 100 parts of rubber polymer, more specifically, 0.5 to 10 parts of phloroglucinol resin per 100 parts of rubber polymer, and even more specifically, 1 to 5 parts of phloroglucinol resin per 100 parts of rubber polymer.

[0083] Sulfur donating compounds may also be added to the rubber composition. Sulfur donating compounds may be used to crosslink the rubber polymer to form a crosslinked primary network. Without being bound by theory, it is believed that sulfur donating compounds donate sulfur atoms under curing conditions. Sulfur donating compounds are typically composed of two or more sulfur atoms bonded together to form a chain of sulfur atoms. Polysulfides and elemental sulfur are sulfur donating compounds, preferably sulfur, S8.

[0084] Vulcanization can be carried out in the presence of a sulfur-donating compound (commonly referred to as a vulcanizing agent). It reacts with a rubber polymer containing a carbon-carbon double bond to form a crosslinked or cured rubber. Some non-limiting examples of suitable sulfur-vulcanizing agents include, for example, elemental sulfur (free sulfur) or a sulfur-donating compound, such as the non-limiting examples of amino disulfide, polymerized polysulfide or sulfur-olefin adducts. In the method for preparing a rubber composition, in the mixing step referred to as a productive mixing step, these and other known and conventional vulcanizing agents are added in a common amount.

[0085] The sulfur-donating compound is generally used in an amount of about 0.1 to about 5 phr, more preferably about 1 to about 3 phr, and even more preferably about 1.5 to about 2.5 phr.

[0086] The rubber composition may be mixed with other conventional additive materials, such as retarders and accelerators, processing additives (e.g., oils), resins (e.g., tackifying resins), plasticizers, pigments, fatty acids, zinc oxide, waxes, antioxidants and antiozonants, peptizers, etc. These and / or other rubber additives are used in conventional amounts, depending on the intended use of the rubber composition.

[0087] If desired, a vulcanization accelerator may also be used. Non-limiting examples of vulcanization accelerators include benzothiazoles, alkylthiuram disulfides, guanidine derivatives, and thiocarbamates. Other examples of such accelerators include, but are not limited to, mercaptobenzothiazole, tetramethylthiuram disulfide, tetrabenzylthiuram disulfide, benzothiazole disulfide, diphenylguanidine, zinc dithiocarbamate, alkylphenol disulfide, zinc butyl xanthate, N-dicyclohexyl-2-benzothiazolesulfenamide, N-cyclohexyl-2-benzothiazolesulfenamide, N-oxydivinylbenzothiazole-2-sulfenamide, N,N-diphenylthiourea, dithiocarbamoylsulfenamide, N,N-diisopropylbenzothiazole-2-sulfenamide, zinc-2-mercaptotoluene imidazole, dithiobis(N-methylpiperazine), dithiobis(N-β-hydroxyethylpiperazine), and dithiobis(dibenzylamine). In another embodiment, other additional sulfur donors include, for example, thiuram and morpholine derivatives. In more specific embodiments, representatives of such donors include, but are not limited to, dimorpholine disulfide, dimorpholine tetrasulfide, tetramethylthiuram tetrasulfide, benzothiazole-2,N-dithiomorpholine, thioplast, dipentamethylenethiuram hexasulfide, and caprolactam disulfide.

[0088] Accelerators can be used to control the time and / or temperature required for vulcanization, and improve the performance of the vulcanized product. In one embodiment of the invention, a single accelerator system, i.e., a primary accelerator, can be used. In another embodiment, conventionally and preferably, the total amount of the primary accelerator is about 0.5 to about 4 phr, preferably about 0.8 to about 2.0 phr. In a preferred embodiment, a combination of a primary accelerator and a secondary accelerator can be used, wherein the amount of the secondary accelerator is less, such as about 0.05 to about 3 phr, to activate and improve the performance of the vulcanized rubber. In another embodiment, a delayed action accelerator can also be used. In another embodiment, a vulcanization retarder can also be used. Suitable accelerator types are those non-limiting examples, such as amine, disulfide, guanidine, thiourea, thiazole, thiuram, sulfenamide, dithiocarbamate, xanthate and combinations thereof. In a preferred embodiment, the primary accelerator is a sulfenamide. In another embodiment, if a secondary accelerator is used, it may be a guanidine, dithiocarbamate or thiuram compound, such as tetrabenzylthiuram disulfide, used in an amount of about 0.1 to about 0.3 phr, more preferably about 0.2 phr.

[0089] The amount of optional tackifying resin is from about 0.5 to about 10 phr, preferably from about 1 to about 5 phr. In a preferred embodiment, the amount of processing aid ranges from about 1 to about 50 phr. As a non-limiting example, suitable processing aids may include aromatic, cycloparaffinic and / or paraffinic processing oils and combinations thereof. In another embodiment, the preferred amount of antioxidant is from about 1 to about 5 phr. As a non-limiting example, representative antioxidants include diphenyl p-phenylenediamine and others, for example, those disclosed in Vanderbilt Rubber Handbook (1978), pages 344-346, which are incorporated herein by reference. In another embodiment, the preferred amount of antiozonant ranges from about 1 to about 5 phr. The preferred amount of optional fatty acid (which may include the non-limiting example of stearic acid) ranges from about 0.5 to about 3 phr.

[0090] The preferred amount of zinc oxide ranges from about 2 to about 5 phr. The preferred amount of wax (e.g., microcrystalline wax) ranges from about 1 to about 5 phr. The preferred amount of peptizing agent ranges from about 0.1 to about 1 phr. As non-limiting examples, suitable peptizing agents include pentachlorothiophenol, diphenylaminodiphenyl disulfide, and combinations thereof.

[0091] In one embodiment of the present invention, the rubber composition contains a phloroglucinol resin, and the rubber composition preferably includes (a) at least one rubber polymer for forming a primary grid, (b) at least one reinforcing filler capable of reacting with an organic silane coupling agent; (c) at least one load-bearing path reinforcing interpenetrating grid-forming methylene donor compound; (d) at least one organic silane coupling agent capable of reacting with a reinforcing filler, (e) at least one phloroglucinol resin and (f) at least one sulfur-donating compound, especially sulfur (S8), or at least one sulfur-donating compound, especially sulfur (S8). The rubber polymer may include one or more rubber components, wherein the rubber components total about 100 phr (parts per hundred parts of rubber). In one embodiment of the present invention, natural rubber should account for about 50 to 100 phr of the main polymer blending portion of the rubber composition, preferably about 75 to 100 phr. The reinforcing filler may include about 1 to about 150 phr of the rubber composition, preferably about 15 to 90 phr, and more preferably about 20 to 55 phr. In one embodiment of the present invention, the reinforcing filler is silica, preferably precipitated silica. The organosilane coupling agent itself and / or the material forming the load-bearing path reinforcing interpenetrating network (the methylene donor and phloroglucinol resin forming the network) can include about 6% to 50% by weight of the reinforcing filler in the formulation, preferably about 8% to 25% by weight of the reinforcing filler, and more preferably about 12% to 25% by weight of the reinforcing filler in the formulation.

[0092] Thus, in one or more embodiments, the rubber composition comprises:

[0093] (a) Rubber polymers or polymer mixtures;

[0094] (b) at least one organosilane coupling agent;

[0095] (c) at least one reinforcing filler that is reactive with an organosilane coupling agent;

[0096] (d) at least one methylene donor resin;

[0097] (e) at least one phloroglucinol resin; and

[0098] (f) Optionally, at least one sulfur donating compound.

[0099] In another embodiment, the rubber composition includes about 25 to about 95 weight % of a rubber component based on the total weight of the rubber composition, about 2 to about 70 weight % of a reinforcing filler reactive with an organic silane coupling agent based on the total weight of the rubber composition, about 0.2 to about 25 weight % of a methylene donor resin based on the total weight of the rubber composition, about 0.2 to about 25 weight % of a phloroglucinol resin based on the total weight of the rubber composition, and about 0.2 to about 5 weight % of a sulfur-donating compound based on the total weight of the rubber composition.

[0100] In the cured rubber composition, the primary polymer network is cured to form a crosslinked rubber polymer or crosslinked polymer mixture by subjecting the rubber composition to an elevated temperature and for a time sufficient to react the rubber polymer or rubber polymer mixture (a) with at least one sulfur-donating compound.

[0101] In another embodiment of the present invention, the method for providing the rubber composition described herein includes mixing at least one reinforcing filler, at least one methylene donor resin, at least one organosilane coupling agent, at least one phloroglucinol resin, and at least one optional sulfur-supplying compound with a rubber component (e.g., natural rubber) in an effective amount. In one embodiment of the method according to the present invention, the effective amount of the organosilane coupling agent can be about 0.2 to about 20 weight % based on the total weight of the rubber composition, preferably about 0.5 to about 15 weight %, more preferably about 2 to about 10 weight %. The effective amount of the rubber component can be about 25 to about 95 weight % based on the total weight of the rubber composition, preferably about 50 to about 90 weight %, more preferably about 60 to about 80 weight %. The effective amount of the reinforcing filler reacted with the organosilane coupling agent can be about 2 to about 70 weight % based on the total weight of the rubber composition, preferably about 5 to about 55 weight %, more preferably about 20 to about 50 weight %. The effective amount of the organic resin can be about 0.2 to about 25 weight % based on the total weight of the rubber composition, preferably about 2 to about 15 weight %, more preferably about 5 to about 10 weight %. The effective amount of the active hydrogen-containing compound (e) may be about 0.2 to about 25 weight %, preferably about 2 to about 15 weight %, more preferably about 5 to about 10 weight %, based on the total weight of the rubber composition. The effective amount of the sulfur-donating compound may be about 0.2 to about 5 weight %, preferably about 0.5 to about 2.5 weight %, more preferably about 1 to about 2 weight %, based on the total weight of the rubber composition.

[0102] In another embodiment of the present invention, the method for preparing the rubber composition may optionally include curing the rubber composition before, during and / or after molding the rubber composition. The vulcanized rubber composition should contain a sufficient amount of load path reinforcing interpenetrating networks to help increase modulus and improve wear resistance.

[0103] In one embodiment of the present invention, the organosilane coupling agent is added separately to the process mixture containing the rubber polymer component. It can be considered that the reinforcing filler couples or reacts in situ with the organosilane coupling agent to form a reinforcing filler in which the organosilane coupling agent and the filler are chemically bonded.

[0104] In one embodiment of the invention, the method for preparing the rubber composition comprises a plurality of steps. In the non-productive step (i), the rubber component, reinforcing filler, methylene donor resin and organosilane are mixed under reactive mechanical processing conditions. As used herein, the expression "reactive mechanical processing conditions" should be understood as the high temperature, residence time and shearing conditions that are prevalent in mechanical processing equipment (such as extruder, meshing mixer or tangential mixer), which are sufficient to achieve one or more of the following situations.

[0105] The reaction of the organosilane coupling agent with water on the reinforcing filler during hydrolysis may form alkoxymethylamino functional silanols. The reaction of these silanols with the reinforcing filler may form covalent chemical bonds with the filler. The reinforcing filler aggregates may break down into smaller aggregates and / or individual filler particles. When dispersed in the rubber polymer, the reinforcing filler may covalently bond with the hydrolyzed and subsequently condensed alkoxymethylamino functional silane.

[0106] In a non-productive step (ii), a methylene donor and a phloroglucinol resin are added to the mixture of step (i). In a non-productive step (ii), all components (except, in this embodiment, the sulfur-donating compound) are mixed under reactive mechanical processing conditions, wherein conditions of elevated temperature, residence time, and shear prevail within the mechanical processing equipment (e.g., an extruder, an intermeshing mixer, or a tangential mixer) sufficient to achieve one or more of the following, namely, dispersion of the rubber polymer, the reinforcing filler covalently bonded to the hydrolyzed and subsequently condensed organosilane coupling agent of step (i), the methylene donor, and the phloroglucinol resin in the mixture; and / or reaction of the reinforcing filler covalently bonded to the hydrolyzed and subsequently condensed organosilane coupling agent with the methylene donor and the phloroglucinol resin; and / or alternatively, reaction of the methylene donor with the phloroglucinol resin to form a load-bearing path-reinforcing interpenetrating network dispersed within the primary network and provide an uncured rubber composition.

[0107] If the methylene donor or phloroglucinol resin is not added in step (ii), the missing ingredients can be added in a second non-productive mixing step (ii).

[0108] In the productive step (iii), the sulphur donating compound (f) is added to the mixture of step (ii).

[0109] In any of steps (i), (ii) or (iii), other components may be added to the rubber composition. Representative and non-limiting examples of other components include activators, processing aids, accelerators, waxes, oils, antiozonants and antioxidants.

[0110] The rubber composition is typically mixed under high shear conditions in a mixing device and the rubber composition spontaneously heats up during the mixing process, primarily due to the shear and associated friction occurring in the rubber mixture.

[0111] In a preferred embodiment of the present invention, the mixture of the desired amount of rubber polymer, reinforcing filler, methylene donor and organosilane coupling agent in step (i) is substantially uniformly mixed under reactive mechanical processing conditions in a mixing step (i) performed continuously or discontinuously. When overheating accumulation may occur and the rubber composition may need to be cooled, discontinuous mixing may be adopted. The cooling of the rubber will avoid or minimize the thermal decomposition of the rubber polymer component or other components in the rubber composition. Preferably, the mixing step (i) is carried out at a temperature of 100°C to 200°C, more preferably at a temperature of 140°C to 180°C.

[0112] In step (iii), at least one sulfur supplying compound (f) can be mixed with the rubber composition from step (ii) together with other vulcanization accelerators.Mixing should be completed under non-reactive mechanical processing conditions.Statement " non-reactive mechanical processing " condition used herein should be understood to refer to the temperature, residence time and shearing conditions that are ubiquitous in mechanical processing equipment (such as extruder, meshing mixer, tangential mixer or roller mill) and are lower than ambient temperature, ambient temperature or slightly elevated, these conditions are enough to make sulfur supplying compound (such as vulcanizing agent) and vulcanization accelerator be dispersed in the rubber composition of step (ii), and will not cause any obvious vulcanization to occur in rubber composition.Advantageously adopt low temperature and low shear in step (iii).

[0113] In step (iii), the residence time can vary widely and is generally selected to completely disperse the vulcanizing agent. In most cases, the residence time ranges from 0.5 to 30 minutes, preferably from 5 to 20 minutes.

[0114] The temperature used in step (iii) is in the range of 5° C. to 150° C., preferably 30° C. to 120° C., more preferably 50° C. to 110° C. These temperatures are lower than those used for reactive machining conditions to prevent or inhibit premature curing of the sulfur-curable rubber (sometimes referred to as scorching of the rubber composition), which may occur at higher temperatures.

[0115] The temperature of the rubber composition may be cooled to 50° C. or lower, for example, during or after step (iii) or between step (i) and step (ii) or between step (ii) and step (iii).

[0116] In another embodiment of the present invention, when it is desired to mold and cure the rubber composition, the rubber composition is placed in a desired mold and heated to at least about 130°C up to about 200°C for 1 to 60 minutes to vulcanize the rubber.

[0117] According to a preferred embodiment of the present invention, a rubber composition preferably used to form a tire tread portion comprises (a) a rubber main polymer or a polymer blend, (b) reinforcing silica filler particles, (c) a methylene donor capable of forming a load-bearing path reinforcing interpenetrating network, which can be generated in situ, (d) an organic silane coupling agent that can react with the reinforcing filler and / or (e) an active hydrogen-containing compound, i.e., at least one phloroglucinol resin, wherein components (b), (c), (d) and (e) contribute to the aforementioned load-bearing path reinforcing interpenetrating network.

[0118] The rubber composition herein can be used for various purposes. In one embodiment of the present invention, a kind of article is provided, wherein at least one component is a cured rubber composition as described herein. In another embodiment herein, a kind of tire is provided, wherein at least one component (such as tread) is a cured rubber composition as described herein.

[0119] In another preferred embodiment, for example, the rubber composition can be used to make articles such as soles, hoses, seals, cable sheaths, washers and other industrial products. Such articles can be constructed, shaped, molded and cured by various known and conventional methods apparent to those skilled in the art. In particular, compositions and methods according to the present invention are particularly suitable for making tires, particularly truck or bus tires.

[0120] Example

[0121] To demonstrate the practice of the present invention, the following examples were prepared and tested. However, these examples should not be considered to limit the scope of the present invention. The claims will be used to define the present invention. The abbreviation PG means phloroglucinol.

[0122] Example 1 of PG resin

[0123] 440.0 g of phloroglucinol, 628.7 g of acetone, and 349.3 g of an acidic cation exchange catalyst (DIAION PK212LH, Mitsubishi Chemical Corporation) were added to a flask, heated to 70° C., and the reaction was maintained at about 70° C. for 24 hours. Then 0.4 g of a 25% sodium hydroxide solution was added. The solvent was then removed by vacuum distillation to 155° C. When the temperature reached 155° C., the vacuum was released and the resin was discharged from the flask.

[0124] Table 1 lists the ingredients used to prepare rubber compositions using natural rubber. The compositions contain silica coupled with bis[3-(triethoxysilyl)propyl]tetrasulfide (TESPT) or a mercaptosilane coupling agent, a methylene donor compound, and resorcinol or a resorcinol resin as a control. The compositions contain a mercaptosilane coupling agent, a methylene donor compound, and a synthetic phloroglucinol resin. A "non-productive" combination refers to an uncured material combination, and a "productive" combination is used to produce a cured composition. In order to illustrate the prior art of truck and bus tire treads, a composition containing N121 carbon black was also prepared.

[0125] All four formulations (TESPT, mercaptosilane coupling agent, hexa(methoxymethyl)melamine with resorcinol or resorcinol-formaldehyde resin (Penacolite), and mercaptosilane coupling agent hexa(methoxymethyl)melamine with phloroglucinol resin) were mixed in an internal rubber mixer using a mixing procedure that included three consecutive non-productive mixing steps followed by a final productive (cured) mix. The silica formulation containing TESPT was heat treated at 145°C for 150 seconds during all three non-productive treatments. The silica formulation containing the methylene donor compound and the resin was heat treated at 155°C for 150 seconds in the first non-productive step, at 150°C for 150 seconds in the second non-productive step, and at 140°C for 150 seconds in the third non-productive step. Hexa(methoxymethyl)melamine and resorcinol, Penacolite or phloroglucinol resin for in-situ polymerization of load-bearing path-reinforced interpenetrating grids are added in the second and third non-productive stages, respectively. The phr contents of hexa(methoxymethyl)melamine and resorcinol are optimized to ensure that the Shore A hardness of the cured compound is within the typical range of truck tire formulations (Shore A hardness of 60-65) and to achieve the best balance of physical and dynamic properties. The rubber composition shown in Table 1 was cured at 160°C for 15 minutes. The resulting dynamic and physical properties are shown in Tables 2 and 3 below, respectively.

[0126] Table 1

[0127]

[0128]

[0129]

[0130] 1 Natural rubber cis-1,4-polyisoprene as SIR20 standard: Indonesian rubber

[0131] 2 Zeosil 1165MP-Solvay

[0132] 3 N121 Carbon Black-Columbia Chemicals

[0133] 4 N-1,3-Dimethylbutyl-N-phenyl-p-phenylenediamine - Harwick Standard Distribution Company

[0134] 5 2,2,4-Trimethyl-1,2-dihydroquinoline polymer-NOCIL

[0135] 6 N-Cyclohexyl-2-benzothiazole sulfonamide - Harwick Standard Distribution Company

[0136] 7Diphenylguanidine - Harwick Standard Distribution Company

[0137] Table 2

[0138]

[0139]

[0140] Table 3

[0141] Compound DIN wear Sample 5 116 Sample 1 229 Sample 2 171 Sample 3 137 Sample 4 141

[0142] The compounds containing mercaptosilane coupling agent, methylene donor compound and resorcinol or resorcinol resin showed better wear resistance and abrasion resistance than the TESPT compounds when measured using DIN abrasives and angle abrasives (at 12° and 16° slip angles, under normal loads of 61N and 123N, respectively, using a grindstone as a grinding surface). However, unexpectedly, the compounds containing mercaptosilane coupling agent, methylene donor compound and resorcinol resin showed better rolling resistance performance (tanD at 60°C) than the other compounds when measured using dynamic mechanical analysis Metravib. This means that the present invention not only obtains a NR / silica tread system without resorcinol, but also makes progress in improving low rolling resistance.

[0143] As can be appreciated, PG Resin 1 performs unexpectedly well, with rolling resistance being 48% better than the carbon black control, 30% better than Penacolite, 13% better than resorcinol, and 17% better than TESPT, while the compound of Example 1 retaining PG Resin has a DIN wear improvement of 62% over TESPT, 21% over resorcinol, and comparable to Penacolite.

[0144] Example 2 of PG resin

[0145] 440.0 g of phloroglucinol, 628.7 g of acetone, and 349.3 g of an acidic cation exchange catalyst (DIAION PK212LH, Mitsubishi Chemical Corporation) were added to a flask, heated to 70° C., and the reaction was maintained at about 70° C. for 24 hours. Then 0.4 g of a 25% sodium hydroxide solution was added. The solvent was then removed by vacuum distillation to 155° C. When the temperature reached 155° C., the vacuum was released and the resin was discharged from the flask.

[0146] Table 2 lists the ingredients used to prepare rubber compositions using natural rubber. The compositions contain silica coupled with a TESPT coupling agent, a methylene donor compound, and a phloroglucinol resin, which is similar to the previous examples as a control. The compositions contain high and low levels of methylene donor compounds, high and low levels of TESPT, and high and low levels of synthetic phloroglucinol resins. The "non-productive" combinations refer to uncured material combinations, and the "productive" combinations are used to produce cured compositions with low and high sulfur contents.

[0147] All three formulations (normal sulfur, high sulfur, low sulfur) were mixed in an internal rubber mixer using a mixing procedure that included three consecutive non-productive mixing steps followed by a final productive (cured) mixture. All three formulations were processed identically. The first mix was continued at 65 rpm for 3 minutes to ensure uniform mixing, followed by 80 rpm for 3 minutes to complete the distribution of the additives. The mixing of the first masterbatch was completed after a two-minute silanization treatment at 160°C. The second process was mixed at 140°C for two minutes and held at 140°C for 1.5 minutes before pouring. The third mixing process was mixed at 40 rpm for 1.5 minutes and then held at 100°C for 1 minute. The productive step was mixed for 1.5 minutes and held at 100°C for 1 minute. The phr values ​​of silane, HMMM, TESPT, resin, and sulfur were adjusted to produce similar physical properties.

[0148] Table 4

[0149]

[0150]

[0151] 1 cis 1,4 polyisoprene natural rubber as SIR20-standard: Indonesian rubber

[0152] 2 Ultrasil 7000 GR

[0153] 3 N121 Carbon Black-Columbia Chemicals

[0154] 4 N1,3-Dimethylbutyl-N-phenyl-p-phenyl-p-phenylenediamine - Harwick Standard Distribution Company

[0155] 5 2,2,4-Trimethyl-1,2-dihydroquinoline polymer-NOCIL

[0156] 6 N-Cyclohexyl-2-benzothiazole sulfonamide - Harwick Standard Distribution Company

[0157] 7Diphenylguanidine - Harwick Standard Distribution Company

[0158] Table 5

[0159] <![CDATA[ Compound ]]> <![CDATA[ tanD at 60℃ ]]> Sample 1 0.073 Sample 2 0.070 Sample 3 0.072

[0160] Table 6

[0161] <![CDATA[ Compound ]]> <![CDATA[ hardness ]]> Sample 1 65 Sample 2 64.8 Sample 3 64.8

[0162] Table 7

[0163]

[0164]

[0165] Table 8

[0166] <![CDATA[ Compound ]]> <![CDATA[ Elongation % ]]> Sample 1 488 Sample 2 505 Sample 3 493

[0167] All three experimental compounds exhibited comparable physical properties. Without being bound by theory, high sulfur content can be compensated by low levels of interpenetrating network monomers. Low sulfur compounds are compensated by high levels of interpenetrating network components. Surprisingly, the path-bearing interpenetrating network can fully compensate the primary network over a wide range of additions.

[0168] Those skilled in the art will appreciate that hardness is a predictor of wear performance in the DIN wear test.

[0169] Various modifications and alterations will be apparent to those skilled in the art without departing from the scope and spirit of the invention.The present invention should not be properly limited to the illustrative embodiments set forth herein.

Claims

1. A rubber composition comprising: (a) rubber polymers or polymer blends; (b) at least one organosilane coupling agent; (c) at least one reinforcing filler, the reinforcing filler being reactive with the at least one organosilane coupling agent; (d) at least one methylene donor compound; (e) at least one phloroglucinol resin; and (f) at least one sulfur donating compound.

2. The rubber composition according to claim 1, wherein the rubber component (a) is about 25 to about 95 weight % of the total weight of the rubber composition; the organosilane coupling agent (b) is 0.05 to 30 parts of the organosilane coupling agent (b) per 100 parts of the rubber polymer; the reinforcing filler (c) reacted with the organosilane coupling agent (b) is 1 to 150 parts of the reinforcing filler per 100 parts of the rubber polymer; the methylene donor compound (d) is 0.1 to 30 parts of the methylene donor compound per 100 parts of the rubber polymer; the phloroglucinol resin (e) is 0.1 to 10 parts of the phloroglucinol resin per 100 parts of the rubber polymer; and the sulfur-donating compound (f) is 0.1 to 5 parts of the sulfur-donating compound per 100 parts of the rubber compound.

3. The rubber composition according to claim 2, wherein the rubber polymer (a) is selected from natural rubber (NR), synthetic polyisoprene (IR), polybutadiene (BR), various copolymers of butadiene, copolymers of isoprene, solution styrene-butadiene rubber (SSBR), emulsion styrene-butadiene rubber (ESBR), ethylene-propylene terpolymer (EPDM), acrylonitrile-butadiene rubber (NBR), and functionalized rubber modified by at least one of an alkoxysilane group, a tin-containing group, an amino group, a hydroxyl group, a carboxylic acid group, a polysiloxane group, an epoxy group or a phthalocyanine group.

4. The rubber composition according to claim 2, wherein the rubber polymer (a) comprises natural rubber or a mixture of natural rubber and butadiene rubber.

5. The rubber composition according to claim 2, wherein the reinforcing filler (c) is selected from fibers, particles or plate-like structures comprising metalloid oxides or metal oxides having surface hydroxyl groups.

6. The rubber composition according to claim 5, wherein the reinforcing filler (c) comprises precipitated silica.

7. The rubber composition according to claim 2, wherein the methylene donor compound (d) is selected from the group consisting of polyisocyanates, polyisocyanurates, epoxy resins, amino resins and polyurethanes.

8. The rubber composition according to claim 7, wherein the amino resin is selected from the group consisting of 1,1,3,3-tetramethoxymethyl urea, 1,3,3-trimethoxymethyl urea, 1,3-bismethoxymethyl urea, 1,1-bismethoxymethyl urea, 1,1,3,3-tetraethoxymethyl urea, 1,3,3-triethoxymethyl urea, 1,3-bisethoxymethyl urea, 1,1-bisethoxymethyl urea, 1,1,3,3-tetrapropoxymethyl urea, 1,3,3-tripropoxymethyl urea, 1,3-bispropoxymethyl urea, 1,1-bispropoxymethyl urea, 1,1,3,3-tetrabutoxymethyl urea, 1,3,3- 1,1,3,3-tetraphenoxymethyl urea, N-(1,3,3-triethoxymethylureidomethyl)-1,1,3,3-tetraethoxymethyl urea, N,N′-bis-(1,1,3-triethoxymethylureidomethyl)-1,3-bisethoxymethyl urea, N,N′-bis-(1,1,3-triethoxymethylureidomethoxymethyl)-1,3-bisethoxymethyl urea, N,N,N′,N′,N″,N″-hexamethoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″-pentamethoxymethyl-[1, 3,5]triazine-2,4,6-triamine, N,N,N′,N″-tetramethoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″,N″-hexaethoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″-pentaethoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N″-tetraethoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″,N″-hexapropoxymethyl-[1,3,5]triazine -2,4,6-triamine, N,N,N′,N′,N″-pentapropoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N″-tetrapropoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″,N″-hexaphenoxymethyl-[1,3,5]triazine-2,4,6-triamine, N,N,N′,N′,N″-pentaphenoxymethyl-[1,3,5]triazine-2,4,6-triamine and N,N,N′,N″-tetraphenoxymethyl-[1,3,5]triazine-2,4,6-triamine.

9. The rubber composition according to claim 2, wherein the phloroglucinol resin (e) has a structure represented by formula (I): in, R 1 , R 2 and R 3 At least one of them combines with the second phloroglucinol unit to form a disubstituted methylene bridge, wherein R 1 , R 2 and R 3 The second one in is a hydrogen atom, or it combines with the third phloroglucinol unit to form another disubstituted methylene bridge, wherein R 1 , R 2 and R 3 The third atom is a hydrogen atom.

10. The rubber composition according to claim 9, wherein the phloroglucinol resin is solid, wherein the phloroglucinol resin has the chemical structure shown in claim 9, wherein the disubstituted methylene bridge formed is an isopropyl bridge.

11. The rubber composition according to claim 9, wherein the phloroglucinol resin is solid, the phloroglucinol resin having the chemical structure shown in claim 9, wherein the disubstituted methylene bridge formed is a 2,2 disubstituted butane bridge.

12. The rubber composition according to claim 9, wherein the phloroglucinol resin is solid, wherein the phloroglucinol resin has the chemical structure shown in claim 9, wherein the disubstituted methylene bridge formed is a 2,2 disubstituted 4-methylpentane bridge. 13 . The rubber composition according to claim 2 , wherein the solid phloroglucinol resin is a reaction product of phloroglucinol and a ketone in the presence of an acidic catalyst.

14. The rubber composition according to claim 12, wherein the solid phloroglucinol resin is as described in claim 12, wherein the ketone is selected from the group consisting of acetone, methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK).

15. The rubber composition according to claim 2, wherein the sulfur-donating compound (f) is sulfur.

16. A method for preparing the rubber composition of claim 2.

17. A cured rubber composition prepared from the composition of claim 2.

18. An article comprising the cured rubber composition of claim 17.

19. The article of claim 18, wherein the article is a component of a tire.

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