Rubber compound of functionalized conjugated diene rubber and silica filler
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- ARLANXEO DEUT GMBH
- Filing Date
- 2023-05-26
- Publication Date
- 2026-06-10
Abstract
Description
Technical Field
[0001] Synthetic rubbers are used in many different applications. They are typically combined with one or more fillers to produce rubber compounds, which are then shaped into articles or combined with other components to produce articles. The main uses of synthetic rubbers include tires or tire components such as tire treads. Typically, conjugated diene rubbers are homopolymers of conjugated dienes or copolymers of at least one conjugated diene monomer and are used for this purpose.
Background Art
[0002] There is a continuing need to improve the properties of tires, and in particular the properties of tire treads. It has been found here that a combination of a conjugated diene rubber functionalized to have at least a functional group and a specific silica filler can be advantageously used to form a rubber compound for manufacturing a tire or a tire tread.
Summary of the Invention
Means for Solving the Problems
[0003] Accordingly, in one aspect, there is provided a method for producing a rubber comprising the step of combining a conjugated diene polymer and a silica filler, wherein the silica filler has a SiO2 content of at least 80% by weight based on the weight of the filler and is obtained from biomass ash containing rice husk ash, and the conjugated diene polymer is a homopolymer of a conjugated diene or a copolymer of at least one conjugated diene selected from the group consisting of butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 1-phenyl-1,3-butadiene, 1,3-hexadiene, and the conjugated diene polymer is functionalized with -OX, -OR, -COOX, -COOR, -N(R’1)(R’2)X nor a combination thereof [wherein X represents H or a cation, n is 1 or 0, and when n is 1, the nitrogen atom N is positively charged, R represents a C1-C6 alkyl group, and R'1 and R'2 are each independently H, a C1-C6 alkyl group, or a -Si(R'4)(R'5) group (wherein R'4 and R'5 each independently represent a C1-C6 alkyl group)], and has at least one functional group containing at least one polar group selected therefrom.
[0004] In another aspect, there is provided a rubber compound obtained by this method.
[0005] In a further aspect, there is provided a method for forming an article, which includes subjecting a curable composition containing a compound and a curing agent capable of curing a conjugated diene polymer to at least one curing reaction.
[0006] In another aspect, there is provided an article obtained by a process including the step of curing a composition containing this compound, and this process includes at least one shaping step, and the shaping step can be carried out before, during, or after curing.
DETAILED DESCRIPTION OF THE INVENTION
[0007] In the following description, the terms "comprising", "containing", "including", and "having" are intended to have a non-exclusive meaning that allows, for example, the presence of additional components, elements, steps, or techniques. For example, a composition "comprising component X" means a composition that contains component X but optionally contains additional components other than component X. For an exclusive meaning, the term "consisting of" is used. A composition "consisting of component X" means a composition that contains component X but does not contain other components.
[0008] In the following description, a standard may be used. Unless otherwise specified, the standard used is the version that was effective as of March 1, 2020. For example, if there is no effective version on that date, such as because the standard has expired, the version that was effective on the date closest to March 1, 2020 is referred to.
[0009] In the following description, the amounts of the components of a composition or polymer may be equivalently indicated by "weight percent", "wt.%", or "weight %". The terms "weight percent", "wt.%", or "weight %" are each based on the total weight of the composition or polymer, which is 100% unless otherwise specified.
[0010] The term "phr" means parts per 100 parts of rubber, that is, the weight percent when the total amount including rubber is 100.
[0011] The ranges specified in this disclosure include and disclose all values between the endpoints of the range and, unless otherwise specified, include the endpoints.
[0012] The term "substituted" is used to represent a hydrocarbon-containing organic compound in which at least one hydrogen atom is substituted by a chemical entity other than hydrogen. This chemical entity is equivalently referred to as a "substituent", "residue", or "group" in this specification. For example, the term "methyl group substituted with fluorine" refers to a fluorinated methyl group and includes the groups -CF3, -CHF2, and -CH2F. The term "unsubstituted" is for representing a hydrocarbon-containing organic compound in which none of its hydrogen atoms are substituted. For example, the term "unsubstituted methyl residue" refers to methyl, that is, -CH3.
[0013] Conjugated diene polymer The conjugated diene polymer according to the present disclosure is obtainable by a polymerization reaction including the polymerization of at least one conjugated diene as a monomer. Preferably, the diene polymer is a homopolymer or a copolymer of at least one conjugated diene, preferably selected from 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 1-phenyl-1,3-butadiene, 1,3-hexadiene. 1,3-Butadiene and / or isoprene are particularly preferred.
[0014] In one embodiment of the present disclosure, the diene polymer is a polybutadiene homopolymer, more preferably a 1,3-butadiene homopolymer. In other embodiments of the present disclosure, the diene polymer is a 1,3-butadiene-copolymer.
[0015] In other embodiments of the present disclosure, the diene polymer is a copolymer of a conjugated diene, preferably butadiene, wherein the copolymer comprises units derived from one or more of the above conjugated dienes and / or one or more vinyl aromatic monomers, and optionally, one or more units derived from one or more other comonomers. Examples of vinyl aromatic monomers include, but are not limited to, styrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, para-t-butylstyrene, vinylnaphthalene, and combinations thereof. Styrene is particularly preferred.
[0016] The vinyl aromatic monomer is also a substituted vinyl aromatic monomer, wherein one or more hydrogen atoms of the vinyl aromatic monomer are substituted with a heteroatom or a group having one or more heteroatoms selected preferably from Si, N, O, H, Cl, F, Br, S, and combinations thereof. The substituted monomer also includes one or more functional groups having one or more heteroatoms or a vinyl aromatic monomer having a unit containing at least one functional group having one or more heteroatoms. Preferably, the heteroatom is selected from Si, N, O, H, Cl, F, Br, S, and combinations thereof. Examples of the functional group include, but are not limited to, hydroxy, thiol, thioether, ether, halogen carboxylic acid group or its salt, and combinations thereof. Such a functionalized conjugated monomer is preferably copolymerized with one or more of the above vinyl aromatic monomers.
[0017] In a preferred embodiment, the diene polymer according to the present disclosure includes repeating units derived from 1,3 - butadiene and styrene.
[0018] Preferably, the polymer according to the present disclosure contains units derived from at least 50% by weight, preferably at least 60% by weight of 1,3 - butadiene, based on the weight of the polymer. In one embodiment of the present disclosure, the diene polymer contains units derived from at least 60% by weight, or at least 75% by weight of 1,3 - butadiene. In one embodiment, the polymer according to the present disclosure includes units derived from at least 75% by weight or at least 95% by weight of one or more conjugated diene monomers.
[0019] In one embodiment of the present disclosure, the diene polymer contains units derived from 0 to 49% by weight or 0 to 40% by weight of one or more comonomers, based on the total weight of the polymer.
[0020] In one embodiment, the diene polymer of the present disclosure contains units derived from 0 to 20% by weight of one or more conjugated dienes other than 1,3 - butadiene.
[0021] In one embodiment, the diene polymer according to the present disclosure comprises, based on the weight of the polymer, at least 50 wt%, preferably at least 60 wt%, of units derived from 1,3-butadiene, and at least 5 wt%, preferably 49 wt% or less, of units derived from one or more vinyl aromatic comonomers, preferably 5-40 wt% or 10-35 wt% of units derived from one or more vinyl aromatic comonomers, preferably containing styrene. Optionally, such a polymer may contain 0-25 wt% of one or more other comonomers, provided that the total amount of monomers is adjusted so that the polymer still has a total weight of 100%. In one embodiment, the polymer according to the present disclosure comprises 55-92 wt% of units derived from one or more conjugated diene monomers and 5.8-45 wt% of units derived from a vinyl aromatic comonomer.
[0022] Other conjugated dienes suitable as comonomers include, but are not limited to, myrcene, ocimene and / or farnesene. The conjugated diene may also be a substituted conjugated diene containing one or more heteroatoms selected from Si, N, O, H, Cl, F, Br, S and combinations thereof, or a functional group containing one or more heteroatoms, for example, a functional group having one or more heteroatoms selected from Si, N, O, H, Cl, F, Br, S and combinations thereof, wherein one or more hydrogen atoms of the diene are replaced. Examples of functional groups include, but are not limited to, hydroxy, thiol, thioether, ether, halogen, amine, silane, and units having one or more carboxylic acid groups or salts thereof, and combinations thereof. Such functionalized conjugated dienes are preferably copolymerized with one or more of the above conjugated dienes.
[0023] Suitable comonomers further include one or more α-olefins, such as ethene, propene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and combinations thereof. In one embodiment, the diene polymer according to the present disclosure contains units derived from 0 to 20% by weight of one or more α-olefins.
[0024] Suitable comonomers also include, but are not limited to, one or more other copolymerizable comonomers that introduce functional groups other than the above functional comonomers, including crosslinking sites, side group sites, side groups, or functionalized groups. In one embodiment of the present disclosure, the diene polymer contains units derived from 0 to 10% by weight or 0 to 5% by weight of one or more of such other comonomers. Examples of such comonomers include divinylbenzene, trivinylbenzene, and divinylnaphthalene.
[0025] Combinations of one or more comonomers of the same chemical species described above, as well as combinations of one or more comonomers from different chemical species, can be used. In one embodiment of the present disclosure, the above other comonomers are absent, or the polymer contains units derived from these in less than 10% by weight, less than 5% by weight, or 1% by weight or less.
[0026] Some or all of the butadiene and other monomers used in the production of the polymers according to the present disclosure can be obtained from fossil resources or sustainable resources. Sustainable resources include renewable materials including plant-based materials, or materials produced by organisms including fungi, microorganisms, and extremophilic microorganisms or enzymes, in which case the monomers are also referred to as "bio-based monomers". Sustainable resources also include recycled materials, for example in the case of ISCC+ certified products. Recycled materials may include recycled plant-based materials and recycled materials that are not of plant origin, for example materials obtained from the conversion of plastic waste or rubber waste including the pyrolysis of tires. The chemical and mechanical properties of the polymers obtained from materials derived from sustainable resources are not different from those obtained from materials derived from fossil resources. Regarding the physical properties of the polymers, they are equivalent except that the monomers obtained from plant-based materials may have a different amount of carbon-14 isotope than those obtained from fossil resources. However, the use of monomers derived from sustainable resources can increase the biological content of the polymers, and in any case, reduce the carbon dioxide footprint of the polymers, thus contributing to the reduction of carbon dioxide generation. Monomers obtained from sustainable resources can replace monomers derived from fossil resources, but the use of monomers obtained from sustainable resources may require additional purification steps to remove impurities derived from their manufacturing processes. Such purification processes are known to those skilled in the art and include, but are not limited to, distillation, absorption onto resins or other adsorbents, and combinations thereof.
[0027] The diene polymers according to the present disclosure preferably have an average molecular weight (number average, Mn) of 10,000 to 2,000,000 g / mol, preferably 100,000 to 1,000,000 g / mol.
[0028] Preferably, the diene polymers according to the present disclosure have a glass transition temperature (Tg) of about -110 °C to about +20 °C, preferably about -110 °C to about 0 °C.
[0029] Preferably, the diene polymer according to the present disclosure has a Mooney viscosity [ML1+4(100 °C)] of about 10 to about 200, preferably about 30 to about 150 Mooney units.
[0030] The polymer typically has a dispersity of about 1.03 to about 3.5.
[0031] The diene polymer can be prepared by methods known in the art. Preferably, the polymer can be obtained by a process including anionic solution polymerization or polymerization using one or more coordination catalysts. The polymerization can be carried out in solution or in the gas phase. The coordination catalyst includes a Ziegler-Natta catalyst or a single-site catalyst system. Preferred coordination catalysts are those based on Ni, Co, Ti, Zr, Nd, V, Cr, Mo, W or Fe.
[0032] The conjugated diene polymer is functionalized. The functionalized conjugated diene polymer can be prepared, for example, by a reaction including the addition of at least one functionalizing agent to a reactive polymer chain produced by the polymerization of a conjugated monomer, and the addition of at least one additional functionalizing agent known in the art may follow. In one embodiment, at least one functional group is formed by a coupling agent designed to additionally form at least one functional group, and the functionalized polymer may be a coupled polymer. The coupling agent can link two or more polymer chains together via a reaction with the coupling agent. In one embodiment, the functional group is formed by a functionalizing agent other than a coupling agent. In one embodiment of the present disclosure, the polymer is obtained by using a coupling agent that forms a functional group in combination with one or more functionalizing agents for generating terminal functional groups simultaneously or subsequently. In one embodiment of the present disclosure, the polymer is a coupled polymer, where the coupled polymer can be produced by using a coupling agent that forms a functional group or a coupling agent that does not form a functional group. In one embodiment, the polymer according to the present disclosure is not coupled.
[0033] Preferably, the diene polymer is functionalized with one or more suitable functionalizing agents to form functional groups at the ends of the polymer or as side groups or parts of the coupled polymers. Preferably, the functional group contains 1 to 20 silicon atoms and, in addition to carbon and hydrogen atoms, optionally contains heteroatoms selected from O, N, and S. Preferably, the polymer is functionalized to have at least one terminal functional group, which may be located at the α-position or ω-position or both of the polymer. Preferably, the functional group contains 1 to 50 carbon atoms, more preferably, the functional group contains 1 to 12 silicon atoms and 1 to 30 carbon atoms, and optionally may further contain one or more heteroatoms selected from S and N or combinations thereof.
[0034] Preferably, the functional group has the formula * -Si(R 1 )(R 2 )-C(R 3 )(R 4 )-, * -Si(R 1 )(R 2 )-O-Si(R 3 )(R 4 )- or contains at least one group selected from combinations thereof, where R 1 , R 2 , R 3 , R 4 are the same or different and are, for example, C1-C 12 alkyl groups optionally containing heteroatoms selected from O, N, S, and Si as alkoxy groups, trialkylsilyl groups, alkylamino groups, dialkylamino groups, and combinations thereof, and H, and * - represents a bond to the polymer chain, and at least one of R 1 and R 2 may also represent the polymer chain.
[0035] Preferably, the functional group further comprises at least one polar group selected from -OX, -OR, -COOX, -COOR, -SX, -N(R’1)(R’2), or combinations thereof, where X represents H or a cation, R represents a C1-C6 alkyl group, and R’1 and R’2 are independently of each other H, a C1-C6 alkyl group, or a -Si(R’4)(R’5) group (wherein R’4 and R’5 independently of each other represent a C1-C6 alkyl group). More preferably, the functional group comprises at least one polar group convertible into an ionic group or exists as an ionic group. Preferred examples include -COOX, -N(R’1)(R’2) groups, and combinations thereof.
[0036] In one embodiment, the functional group is: -SiH2(OH), -SiR2(OH), -SiH(OH)2, -SiR1(OH)2, -Si(OH)3, -Si(OR1)S, -(SiR1R2O) x -R3, -Si(R3) 3-m (X) m and includes at least one silyl, silanol, or siloxane group selected from, where X is a halogen, x is the number of repeating units from 1 to 30, m is the number of bonded groups that varies from 0 to 3, and R1 and R2 can be the same or different and in each case are an alkoxy or alkyl (linear or branched), cycloalkyl, aryl, alkylaryl, aralkyl, or vinyl group having from 1 to 20 carbon atoms, and R3 is H or an alkyl (linear or branched) having from 1 to 20 carbon atoms in each case, or a mononuclear aryl group.
[0037] In one embodiment, the functional group has the formula -[-Si(R1R2)-O-] n-Si(R1R2)-OH group, or consists of this group, where R1 and R2 are the same or different, and in each case are alkoxy or alkyl (linear or branched), cycloalkyl, aryl, alkylaryl, aralkyl or vinyl groups having 1 to 20 carbon atoms, and n represents the number of units of the siloxane functional group before the silanol end group, which varies from 1 to 49, preferably from 1 to 29.
[0038] In one embodiment, the functional group has the formula: * -Si(A 2 -N((H) k (R i ) 2-k )) y (OR i ) z (R3) 3-(y+z) and contains or consists of a group represented by, where k can vary from 0 to 2, y can vary from 1 to 3, z can vary from 0 to 2, 0 < y + z < 3, R1 and R2 are the same or different, and in each case are alkyl (linear or branched), cycloalkyl, aryl, alkylaryl, aralkyl or vinyl groups, mononuclear aryl groups having 1 to 20 carbon atoms, R3 is H, or alkyl (linear or branched) having 1 to 20 carbon atoms in each case, and A2 is a spacer having 12 or fewer carbon atoms, which can be linear or branched, preferably selected from alkyl, allyl or vinyl.
[0039] In one embodiment, at least the functional group is formed by reacting a reactive polymer chain with a silane sulfide modifier described in WO 2014 / 040639 A1 pamphlet or an aminosilane described in EP 2675278 A1 specification.
[0040] Preferably, the functional group includes at least one terminal unit containing at least one group selected from the group consisting of -OX, -OR, -COOX, -COOR, -SX, -N(R’1)(R’2), or combinations thereof, where X represents H or a cation, R represents a C1-C6 alkyl group, and R’1 and R’2 are, independently of each other, H, C1-C 10 alkyl group, or a -Si(R’4)(R’5) group (where R’4 and R’5 are, independently of each other, C1-C 10 alkyl group). In one embodiment of the present disclosure, the functional group does not include an -SX group.
[0041] In one embodiment of the present disclosure, the second functional group is obtainable by a reaction comprising the step of adding a silicon-containing compound or a cyclic urea, or an alkylene oxide, or a combination thereof, to a polymerization reaction. Preferably, the reaction product is reacted with a suitable reagent to obtain at least one terminal unit selected from -OX, -OR, -COOX, -COOR, -SX, -N(R’1)(R’2), or combinations thereof, where X represents H or a cation, R represents a C1-C6 alkyl group, and R’1 and R’2 are, independently of each other, H, C1-C 20 alkyl group, or a -Si(R’4)(R’5) group (wherein R’4 and R’5 are, independently of each other, C1-C 20 alkyl group, preferably a C1-C6 alkyl group).
[0042] The silicon-containing compound is preferably selected from divalent compounds having one Si atom per molecule, or the divalent compound is an open-chain siloxane having 2 to 12 silicon atoms per molecule, or a cyclic siloxane having 3 to 12 silicon atoms per molecule, or a combination thereof. The remaining valences of the silicon atoms are preferably bonded to R groups, wherein each R group is independently selected from the group consisting of hydrogen, alkylcycloalkyl, arylaralkyl, and alkaryl groups having 20 or fewer carbon atoms, where the group may optionally be a hetero group bonded to a carbon chain or carbon ring selected from alkylamines and silylamines. The silicon-containing compound has the formula
Chemical formula
[0043] In one embodiment of the present disclosure, the silicon-containing compound includes 2 to 20, preferably 3 to 15, more preferably 4 to 10 unsaturated siloxane units corresponding to the general formula (1’):
Chemical formula
[0044] In formula (1’), each R1 independently represents an alkenyl selected from the group consisting of vinyl (-CH=CH2), allyl (-CH-CH2-CH=CH2), n-propenyl (-CH2CH=CH2), n-butenyl (-CH2CH2CH=CH2), isobutenyl (-CH2(CH3)CH=CH2); n-pentenyl (-CH2CH2CH2CH=CH2), isopentenyl (-CH2(CH3)CH2CH=CH2, -CH2CH2(CH3)CH=CH2). Each R2 independently represents a chemical bond, H, OH, an alkenyl having 2 to 10 carbon atoms, an alkyl having 1 to 10 carbon atoms (wherein the alkyl or alkenyl chain or both may be interrupted one or more times by an ether oxygen atom), a siloxane or polysiloxane having 10 or fewer silicon atoms (wherein the siloxane or polysiloxane may optionally have at least one silicon atom having at least one aliphatic substituent selected from alkyl or alkenyl groups), or a combination thereof. Preferably, at least one R2 represents methyl. Preferably, all R2 represent methyl or ethyl, or a combination thereof.
[0045] In one embodiment of the present disclosure, the silicone-based compound has the general formula (2’):
Chemical formula
[0046] In another preferred embodiment of the present disclosure, the silicone-containing compound is cyclic and has the formula (3’)
Chemical formula
[0047] In one embodiment of the present disclosure, the unsaturated siloxane coupling agent has the general formula (4’):
Chemical formula
[0048] In another embodiment of the present disclosure, the silicone-containing compound has the formula (5’):
Chemical formula
[0049] In formula (5’), Ra, Rb, Rc, Rd, Re, Rf, Rg and Rh are the same or each different, and these are C1-C 10 alkyl, C2-C6-alkenyl, or -O-Si-(R 1’ R 2’ R 3’ )(wherein R1’, R2’ and R3’ are C1-C 10Independently selected from alkyl, C2-C6-alkenyl, preferably vinyl, preferably at least one of R1’, R2’ and R3’ contains a vinyl unit, preferably all of R1’, R2’ and R’3 are vinyl (-CH=CH2)). Ra, Rb, Rc, Rd, Re, Rf, Rg and Rh are independently selected from at least one, preferably at least two, more preferably at least three, of C2-C6-alkenyl, preferably vinyl (-CH=CH2). In one embodiment of the present disclosure, at least four of Ra-Rh are vinyl, or at least one of the residues Ra-Rh is -O-Si(vinyl)3. In one embodiment of the present disclosure, all of Ra-Rh are vinyl. The compound of formula (5’) is also known as a cage-type silsesquioxane or POSS. The material is commercially available or can be prepared as described, for example, in Quirk, Cheng et al, Macromolecules 2012, 45, 21, 8571-8579.
[0050] Preferably, the coupling agent according to the present disclosure has a molecular weight of 5000 g / mol or less. Preferably, the coupling agent has a molecular weight of less than 2000 g / mol.
[0051] Particularly preferred examples of the coupling agent according to the present disclosure include
Chemical formula
Chemical formula
Chemical formula
Chemical formula
[0052] The silicone-containing compounds also include compounds containing at least one N atom of an amino group, or at least one S atom of a thiol group, or a combination thereof, in addition to Si and O atoms. The amino- and thiol functional groups can be protected, for example, by silyl groups and can be deprotected during post-treatment or compounding. Specific examples include compounds of the formula
Chemical formula
[0053] Homologues of these specific examples can also be used. Homologues include, but are not limited to, corresponding compounds in which the propylene group is replaced by another alkylene group containing, for example, a C2 alkylene, a linear or branched C4-C10 alkylene, or, additionally or alternatively, one or more methyl groups are independently replaced by other linear or branched C2-C8, preferably C2-C4 alkyl groups, or corresponding compounds in which one or more ethyl groups are replaced by a C1 or linear or branched C3-C8, preferably C3-C6 alkyl group.
[0054] In one embodiment, the conjugated diene is functionalized by a reaction involving the addition of a cyclic urea as a functionalizing agent. The cyclic urea preferably corresponds to the general formula
Chemical formula
[0055] The reaction product is treated with a suitable agent to give end groups such as -OX, -OR, -COOX, -COOR, -SX, -N(R'1)(R'2) or combinations thereof [wherein X represents or a cation, R represents a C1-C6 alkyl group, and R'1 and R'2 are independently of each other H, C1-C 10 alkyl group, or -Si(R'4)(R'5) group (wherein R'4 and R'5 are independently of each other C1-C 10At least one terminal unit selected from (representing an alkyl group) can be introduced. Suitable agents include, but are not limited to, acids, alcohols, thioalcohols, and combinations thereof. The carboxylic acid group can be introduced, for example, by treatment with a silalactone-based functionalizing agent or an anhydride-based agent. Treatment with a silactone-based or anhydride-based treatment can also be carried out by direct reaction with a reactive polymer chain. The functionalization of the polymer is described in, for example, WO 2021 / 009154 pamphlet; US Patent No. 3,242,129, US Patent No. 4,020,036, US Patent No. 4,465,809, US Patent Application Publication No. 2016 / 0075809A1, and US Patent Application Publication No. 2016 / 0083495A1, and WO 2021 / 009154 pamphlet, all of which are incorporated herein by reference in their entirety.
[0056] The amino-functionalized initiator can be used for end groups having at least one amino functional group at the α-position of the polymer. Examples of suitable amino-functionalized initiators include: 1-naphthyllithium; allyllithium compounds derived from tertiary N-allylamines such as [1-(dimethylamino)-2-propenyl]lithium, [1-[bis(phenylmethyl)amino]-2-propenyl]lithium, [1-(diphenylamino)-2-propenyl]lithium, [1-(1-pyrrolidinyl)-2-propenyl]lithium; lithium amides of secondary amines such as lithium pyrrolide, lithium piperidide, lithium hexamethylene imide, lithium 1-methylimidazolidide, lithium 1-methylpiperazide, lithium morpholide, lithium dicyclohexylamide, lithium dibenzylamide, lithium diphenylamide. These allyllithium compounds and these lithium amides can also be prepared in situ by the reaction of an organolithium compound with the respective tertiary N-allylamine or the respective secondary amine. The amine-functionalized monomer can also be used to generate an amino-functionalized group at the α-position of the polymer. These can be added before or at the start of polymerization, and / or during polymerization, but not at the end of polymerization. The amine-functionalizable monomer can also be added as an active reaction product containing at least two repeating units derived from the functionalizable monomer. Such an active reaction product can also be produced by the reaction of one or more amine-functionalized monomers with an organometallic compound, such as an initiator for anionic polymerization described above, preferably an organolithium compound, preferably an alkyllithium and more preferably butyllithium. This reaction can include the oligomerization of the amine-functionalized monomer, or the co-oligomerization of the amine-functionalized monomer and one or more other comonomers, such as conjugated dienes as described above. Oligomerization or co-oligomerization can result in an oligomerized functionalizable monomer having 2 to 200 units derived from the amine-functionalized monomer. As used herein, the active reaction product refers to a monomer having an unreacted carbon-carbon double bond capable of participating in the polymerization reaction, or a carbanion capable of participating in the polymerization reaction, or both.The reaction product may be formed in separate reactions and then added to the polymerization reactor, or the reaction product may be formed in situ, for example, by simultaneously feeding one or more amine-functionalized monomers and a reaction initiator to the polymerization reaction, or by first reacting the initiator with the amine-functionalized monomer and then adding the conjugated diene monomer.
[0057] Examples of amine-functionalized monomers include, but are not limited to, those corresponding to formula (1”):
Chemical formula
Chemical formula
Chemical formula
[0058] Specific examples include, but are not limited to, 4-(2-(N,N-bis(trimethylsilyl)amino)ethyl)styrene [Chemical formula] vinylbenzylpyrrolidine, [Chemical formula] and N,N-dimethylaminomethylstyrene [Chemical formula] may be mentioned.
[0059] The conjugated diene polymer can be oil-extended and may contain up to 100 parts of extender oil per 100 parts of the polymer. When the polymer is oil-extended, i.e., when the polymer is combined with one or more extender oils before or during the post-treatment of the polymer, typically before solvent removal, the composition also contains the extender oil as part of the oil-extended polymer. The polymer can be oil-extended when they have a high molecular weight. Polymers with a high molecular weight have a high Mooney viscosity. If the Mooney viscosity is excessively high, the processing of the polymer to form a rubber compound can be difficult or uneconomical. The Mooney viscosity of the polymer can be lowered by adding extender oil before or during the post-treatment of the polymer to provide an oil-extended polymer. The typical amount of extender oil is 10 to 100 parts per 100 parts of the polymer. Examples of extender oils include oils known and used for oil-extending diene rubbers, such as TDAE (treated distillate aromatic extract)-, MES (mild extraction solvate)-, RAE (residual aromatic extract)-, TRAE (treated residual aromatic extract)-, naphthenic oils, paraffinic oils, and hydrides thereof (including oils obtained from terpene-containing plant materials). These are preferably added to the reaction mixture before or during solvent removal.
[0060] Silica filler The silica filler according to the present disclosure is preferably precipitated silica. Precipitated silica is obtained by acidifying a caustic silicate solution to yield a slurry of precipitated silica. A mineral acid, such as sulfuric acid, can be used for the precipitation. The precipitated silica can be separated from the slurry, dried, and optionally ground to a desired particle size. Precipitated silica is typically a powder.
[0061] In a conventional process for producing precipitated silica, a caustic silicate solution is formed by melting high-purity soda ash and silica sand at high temperature in a furnace. However, silica can also be prepared from biomass. In such a process, the caustic silicate solution is formed by the caustic digestion of biomass ash containing silica, such as rice husk ash. The ash is obtained from the pyrolysis of biomass. The process for forming precipitated silica is described, for example, in U.S. Patent No. 6,375,735 B1 and the documents cited therein.
[0062] It has been found here that precipitated silica having a certain distribution of alkali and alkaline earth metal ions, when combined with a conjugated diene polymer according to the present disclosure, results in a tire compound having improved performance parameters. Preferably, the silica filler has an ion number IN1 of less than 3, or an ion number IN2 of less than 20, or both. The ion number N1 is given by the formula: IN1 = [(Mg) + (K)] / [(Ca) + (Na)] × 100 and is calculated according to:
[0063] The ion number IN2 is given by the formula: IN2 = [(Mg) + (Na)] / [(Ca) + (K)] × 100 and is calculated according to:
[0064] In both formulas: (Mg) is the concentration of magnesium ions (mg / 1 kg of silica sample) divided by the atomic weight of magnesium (24 g / mol), i.e., c(Mg 2+ ) / 24 g / mol; (K) is the concentration of potassium ions (mg / 1 kg of silica sample) divided by the atomic weight of potassium (39 g / mol), i.e., c(K + ) / 39 g / mol; (Ca) is the concentration of calcium ions (mg / 1 kg of silica sample) divided by the atomic weight of calcium (40 g / mol); (Na) is the concentration of sodium ions (mg / 1 kg of silica sample) divided by the atomic weight of sodium (23 g / mol).
[0065] Preferably, the silica filler has a potassium content of more than 100 mg per 1 kg of silica sample, a magnesium content of more than 100 mg per 1 kg of silica sample, or both.
[0066] Silica obtained from biomass ash, particularly rice husk ash, is considered to have such a cation distribution. Conventional silica has a different cation distribution and generally contains fewer cations. However, such cations can be added to conventional silica to form the above cation profile.
[0067] The silica filler according to the present disclosure is preferably precipitated silica obtained from biomass ash, preferably biomass ash containing rice husk ash. Preferably, the filler is obtained by a process including caustic digestion of biomass ash, preferably rice husk ash. The ash is preferably obtained from the pyrolysis of biomass. Preferably, the caustic silicate solution is acidified with at least one mineral acid to produce a slurry of precipitated silica, and the process further includes separating the precipitated silica from the slurry.
[0068] The precipitated silica is mainly or completely amorphous. Preferably, the silica filler according to the present disclosure has a SiO2 content of at least 80% by weight, preferably at least 85% by weight, based on the total weight of the filler. Preferably, the silica filler has a surface area (BET) of 30 - 300 m 2 / g, or less than 30 - 190 m 2 / g.
[0069] The filler according to the present disclosure can be used with the functionalized polymer according to the present disclosure at a silica-to-polymer weight ratio of 5:1 to 1:5, preferably 2:1 to 1:2.
[0070] The silica filler according to the present disclosure can be used alone or as a mixture with other silica fillers or one or more fillers that are not silica fillers. In one embodiment of the present disclosure, the rubber composition contains a mixture of the silica filler according to the present disclosure and one or more carbon-based fillers including carbon black. The weight ratio of the silica filler to the carbon-based filler can be from 0.01:1 to 50:1, preferably from 0.05:1 to 20:1. Examples of suitable carbon-based fillers include, but are not limited to, carbon blacks produced by lamp black, channel, furnace, gas black, thermal, acetylene black or arc process. The carbon-based filler can have a BET surface area of 9 to 200 m2 / g. Examples of specific carbon blacks include, but are not limited to, SAF-, ISAF-LS-, ISAF-HM-, ISAF-LM-, ISAF-HS-, CF-, SCF-, HAF-LS-, HAF-, HAF-HS-, FF-HS-, SPF-, XCF-, FEF-LS-, FEF-, FEF-HS-, GPF-HS-, GPF-, APF-, SRF-LS-, SRF-LM-, SRF-HS-, SRF-HM- and MT-black, or N110-, N219-, N220-, N231-, N234-, N242-, N294-, N326-, N327-, N330-, N332-, N339-, N347-, N351-, N356, N358, N375, N472, N539, N550, N568, N650, N660, N754, N762, N765, N774, N787 and N990 carbon blacks according to ASTM. Carbon-based fillers obtained from sustainable resources, for example, from the recycling of rubber or plastic waste containing carbon-based materials obtained by thermal decomposition of tires can also be used.
[0071] Examples of suitable fillers that are neither silica-based nor carbon-based include, but are not limited to, glass fibers and glass fiber products (mats, strands) or microspheres; metal oxides including zinc oxide, calcium oxide, magnesium oxide, aluminum oxide; metal carbonates including magnesium carbonate, calcium carbonate, zinc carbonate; metal hydroxides including aluminum hydroxide, magnesium hydroxide; metal sulfates including calcium sulfate, barium sulfate; and rubber gels based on BR, E-SBR, and / or polychloroprene, preferably having a particle size of 5 to 1000 nm.
[0072] Additional rubbers and rubber additives It is possible to form a vulcanizable rubber compound by a process that includes combining a polymer and silica according to the present disclosure, with the polymer and silica filler, and at least one crosslinking agent for crosslinking at least a conjugated diene polymer. Thus, in one aspect of the present disclosure, there is provided a process for forming a vulcanizable rubber compound that includes combining a polymer according to the present disclosure with at least one silica filler according to the present disclosure, and optionally further includes combining at least one curing agent or a combination thereof that is capable of curing at least a diene polymer, and optionally includes combining one or more additional rubbers and / or rubber additives.
[0073] The rubber compound according to the present disclosure may further contain one or more additional rubbers other than the functionalized rubber according to the present disclosure and at least one rubber additive.
[0074] Examples of additional rubbers include natural rubber and synthetic rubbers. When present, these can be used in amounts in the range of 0.5 to 95% by weight, preferably in the range of 10 to 80% by weight, based on the total amount of rubber in the composition. Examples of suitable synthetic rubbers include BR (polybutadiene), alkyl acrylate copolymers, IR (polyisoprene), E-SBR (styrene-butadiene copolymer produced by emulsion polymerization), S-SBR (styrene-butadiene copolymer produced by solution polymerization), IIR (isobutylene-isoprene copolymer), NBR (butadiene-acrylonitrile copolymer), HNBR (partially or fully hydrogenated NBR rubber), EPDM (ethylene-propylene-diene terpolymer), and mixtures thereof. Natural rubber, E-SBR and S-SBR having a glass transition temperature above -60°C, polybutadiene rubbers having a high cis content (>90%) produced with Ni, Co, Ti or Nd-based catalysts, polybutadiene rubbers having a vinyl content of 80% or less, and mixtures thereof are of particular interest in the manufacture of automotive tires.
[0075] Rubber additives are components that can serve to improve the processing characteristics of the rubber composition, to aid in crosslinking the rubber composition, to improve the physical properties of the vulcanizate produced from the rubber, to improve the interaction between the rubber and the filler, or to aid in binding the rubber to the filler. Rubber auxiliaries include crosslinking agents such as sulfur or sulfur-supplying compounds, reaction accelerators, antioxidants, heat stabilizers, light stabilizers, ozone stabilizers, processing aids, plasticizers, adhesives, blowing agents, dyes, pigments, waxes, extenders, organic acids, silanes, retarders, metal oxides, extender oils such as DAE (distilled aromatic extract), TDAE (treated distilled aromatic extract), MES (mild extraction solvate), RAE (residual aromatic extract), TRAE (treated residual aromatic extract), naphthenes and heavy naphthene oils, and activators. Oils obtained from sustainable resources including renewable resources or recycled materials can also be used. Oils obtained from renewable resources include oils obtained from plants including vegetable oils, or oils obtained from or produced by enzymes from microorganisms.
[0076] The total amount of additional rubber and rubber additives can range from 1 to 300 parts by weight, preferably 5 to 150 parts by weight, based on 100 parts of the conjugated diene polymer according to the present disclosure.
[0077] Examples of typical formulations of rubber compounds are shown in US Patent Application Publication No. 2016 / 0075809 A1, and US Patent Application Publication No. 2016 / 0083495 A1 (Steinhauser and Gross), and International Publication No. 2021 / 009154 Pamphlet (Steinhauser).
[0078] The rubber composition can be prepared with conventional processing equipment for the formation and processing of (vulcanizable) rubber compounds, including rollers, kneaders, internal mixers or mixing extruders. The rubber composition can be produced in a single-stage or multi-stage process, with 2 to 3 mixing stages being preferred. Crosslinking agents, such as sulfur, and accelerators can be added in separate mixing stages, for example to rollers, and a temperature in the range of 30°C to 90°C is preferred. Crosslinking agents, such as sulfur, and accelerators are preferably added in the final mixing stage.
[0079] Use The vulcanizable rubber compound can be subjected to at least one curing reaction to produce a shaped article. The shaped article contains the compound or at least the vulcanized form (i.e., crosslinked form) of the conjugated diene polymer.
[0080] Accordingly, in one aspect, there is provided an article obtained by curing a rubber compound according to the present disclosure. This process may include at least one shaping step, where the shaping step may be performed before, during, or after curing. Preferably, the rubber compound according to the present disclosure is used to form a tire or a tire tread, and the preferred article includes a tire, preferably a tire tread. However, the rubber compounds provided herein are also suitable for the manufacture of other articles, particularly other shaped articles, such as cable sheaths, hoses, drive belts, conveyor belts, roll linings, shoe soles, sealing rings, and damping components.
[0081] The following examples are provided to further illustrate the present disclosure, but it is not intended to limit the present disclosure to the embodiments described in these examples.
[0082] Method Composition of silica samples The composition of the silica samples was determined by X-ray fluorescence (XRF).
[0083] To determine the cation content of the cations used in the calculation of the ion number, 0.5 g of the silica sample was decomposed by dry ashing at 550 °C in a platinum crucible, followed by distilling the ash in hydrochloric acid. After appropriately diluting the decomposition solution with deionized water, the metal content was measured by ICP-OES (inductively coupled plasma-optical emission spectrometry) at the following wavelengths with respect to a calibration solution adapted to the acid matrix. Calcium: 317.933 nm, Magnesium: 285.213 nm, Potassium: 766.491 nm, Sodium: 589.592 nm Depending on the concentration of the elements in the decomposition solution and the sensitivity of the measuring instrument used, the concentration of the sample solution was adapted to the linear region related to the calibration for the wavelength used in each case. The BET surface area can be determined using nitrogen gas in accordance with ISO9277 or ISO18852.
[0084] Number of ions: The number of ions 1 (IN1) was calculated according to Equation (1): IN1 = [(Mg) + (K)] / [(Ca) + (Na)] × 100.
[0085] The number of ions 2 (IN2) was calculated according to Equation (2): IN2 = [(Mg) + (Na)] / [(Ca) + (K)] × 100.
[0086] In Equations 1 and 2: (Mg) is the concentration of magnesium ions (mg / 1 kg of silica sample) divided by the atomic weight of magnesium (24 g / mol), that is, c(Mg 2+ ) / 24 g / mol; (K) is the concentration of potassium ions (mg / 1 kg of silica sample) divided by the atomic weight of potassium (39 g / mol), that is, c(K + ) / 39 g / mol; (Ca) is the concentration of calcium ions (mg / 1 kg of silica sample) divided by the atomic weight of calcium (40 g / mol); (Na) is the concentration of sodium ions (mg / 1 kg of silica sample) divided by the atomic weight of sodium (23 g / mol).
[0087] Molecular weight The molecular weights of the polymer (Mw and Mn, the weight-average and number-average molecular weight moments, respectively) were determined by gel permeation chromatography.
[0088] Properties of vulcanized rubber compound The loss factor tanδ was measured at 0 °C and 60 °C to determine the temperature-dependent dynamic mechanical properties. An EPLEXOR device (Eplexor 500 N) manufactured by GABO was used for this purpose. The measurement was carried out at 10 Hz in an Ares strip within the temperature range of -100 °C to 100 °C in accordance with DIN 53513.
[0089] The rebound resilience at 60 °C was determined in accordance with DIN 53512.
[0090] The tensile strength test was carried out on vulcanized S2 test specimens in accordance with DIN 53504.
[0091] The elastic properties were determined in accordance with DIN53513 - 1990. An elastomer test system (MTS Systems GmbH, 831 Elastomer Test System) was used. With no static pre-strain in the shear direction, vibration was centered around 0 in cylindrical samples (two samples of 20×6 mm each, 5 mm thickness pre-compression), and measurements were taken in double shear mode within a strain range of 0.1 - 40% at a measurement frequency of 10 Hz. This method was used to obtain the following properties: G’(0.5%): Dynamic modulus at an amplitude sweep of 0.5%, G’(15%): Dynamic modulus at an amplitude sweep of 15%, G’ = G’(0.5%) - G’(15%): Difference in dynamic modulus at 0.5% with respect to an amplitude sweep of 15%, tanδ(max): Maximum loss factor (G” / G’) in the entire measurement range at 60 °C.
[0092] The difference between G’(0.5%) and G’(15%) is an indicator of the Payne effect of the mixture. The lower this value, the better the distribution of the filler in the mixture, the better the rubber-filler interaction, and the lower the risk of phase separation.
Examples
[0093] Examples C1 - C4 and Ex1, Ex2 and Ex3 Conjugated diene polymers (Polymers 1 and 2) were mixed with different silicas in a tire tread formulation and then subjected to curing. Polymer 1 was an unfunctionalized styrene-butadiene copolymer. Polymer 2 was a styrene-butadiene copolymer with a similar composition but was functionalized to have terminal polar siloxane units containing carboxylate end groups. Silica 1 was a conventional precipitated silica (ULTRASIL 7000GR, surface area (N2) = 175 m2 / g). Silica 2 was a conventional precipitated silica (ZEOZIL 1165 MP) with a surface area (BET) of 165 m 2 / g. Silicas 3 and 4 were obtained from rice husk ash and had surface areas (BET) of 145 - 175 m 2 / g and 160 + / - 10 m 2 / g, respectively (ORYZAZL HD165MP and BSIL 2160MP). In Example 3, a styrene-butadiene polymer functionalized to have terminal amino groups was used. The compositions of the silicas are shown in Tables 1 and 2. The compositions of the rubber compounds are shown in Table 3. The rubber compounds were subjected to curing to produce vulcanized compositions. The properties of the vulcanizates are shown in Table 4.
[0094]
Table 1
[0095]
Table 2
[0096]
Table 3
[0097]
Table 4
[0098] Comparison of compounds of non-functionalized SSBR and conventional silica with compounds of non-functionalized SSBR and silica obtained from biomass ash (C1 and C3) shows only slight changes in energy dissipation, e.g., rebound at 60 °C, tan δ(0 °C) / tan δ(60 °C), and S300 / S100 reinforcement. In the case of C4, a trade-off between improved dynamic properties and reduced tensile properties was observed. In compounds with conventional silica, replacing non-functionalized SSBR with functionalized SSBR shows an improvement in dynamic properties while the reinforcement parameters remain constant (C5, C6). Combinations of functionalized SSBR and silica obtained from biomass ash (Ex1 vs C1, C3, C5, and Ex2 vs C4) show further improvements in dynamic properties: beneficial wet grip / rolling resistance balance (tan d 0 °C / tan d 60 °C), increased rebound at 60 °C, and improved filler dispersion (Payne effect). Good values including low values of the Payne effect (advantageous for showing improved dispersion with the filler) were also achieved in Ex3. In addition, the reinforcement parameter (S300 / S100) was also improved (Ex1 vs C1, C3, C5, and Ex2 vs C4).
Claims
1. A method for forming a rubber compound, comprising the step of combining a conjugated diene polymer and a silica filler, The silica filler contains at least 80% by weight of SiO based on the weight of the silica filler. ２ It has a content of and is obtained from biomass ash containing rice husk ash, The aforementioned conjugated diene polymer is either a homopolymer of a conjugated diene, or a copolymer of at least one conjugated diene selected from the group consisting of butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 1-phenyl-1,3-butadiene, and 1,3-hexadiene, and The conjugated diene polymer is functionalized, and is —OX, —OR, —COOX, —COOR, —N(R' １ )(R' ２ )X ｎ or a combination thereof [wherein, X represents H or a cation, n is 1 or 0, and when n is 1, the nitrogen atom N is positively charged, R represents a C1-C6 alkyl group, and R' １ and R' ２ are each independently H, C １ -C ６ alkyl group, or -Si(R' ４ )(R' ５ ) group (wherein, R' ４ and R' ５ are each independently C １ -C ６ alkyl group)], and contains at least one functional group containing at least one polar group selected from the above.
2. The at least one polar group is -COOX, -N(R' １ ) (R' ２ ) X ｎ Or a combination thereof [wherein X represents H or a cation, n is 1 or 0, and when n is 1, the nitrogen atom N is positively charged, R' １ and R' ２ H and C are mutually independent. １ ~C ６ Alkyl alkyl group, or -Si(R' ４ ) (R' ５ ) group (wherein, R' ４ and R' ５ These are mutually independent, C １ ~C ６ The method according to claim 1, selected from [representing an alkyl group].
3. The method according to claim 1, wherein the functional group comprises 1 to 20 Si atoms in addition to carbon and hydrogen atoms.
4. The functional group is a unit selected from formula (I) or (II) or a combination thereof: ＊ -Si(R １ )(R ２ )-C(R ３ )(R ４ )- (I)、 ＊ -Si(R １ )(R ２ )-O-Si(R ３ )(R ４ )- (--) It has, In equations (I) and (II), R １ , R ２ , R ３ , R ４ C may be the same or different and may contain heteroatoms optionally selected from O, N, S, and Si. １ ~C １２ Selected from alkyl groups or hydrogen, ＊ - indicates bonding to the polymer chain, R １ and R ２ The method according to claim 1, wherein at least one of the members may also represent a polymer chain.
5. The method according to claim 1, wherein the functional group is obtained by reaction with at least a functionalizing agent, a coupling agent, or a combination thereof that generates a functional terminal group.
6. The method according to claim 1, wherein the functional group comprises 1 to 12 silicon atoms and 1 to 30 carbon atoms.
7. The method according to claim 1, wherein the conjugated diene polymer is a copolymer comprising a unit derived from butadiene and at least one other conjugated diene or at least one vinyl aromatic comonomer or a combination thereof, wherein the vinyl aromatic comonomer is selected from styrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, para-t-butylstyrene, and vinylnaphthalene.
8. The method according to claim 1, wherein the conjugated diene polymer comprises units derived from butadiene and styrene, and the conjugated diene polymer is prepared by anionic solution polymerization.
9. The silica filler has an ion number of less than 3 IN1, an ion number of less than 20 IN2, or both, where IN1 is given by formula: IN1=[(Mg)+(K)] / [(Ca)+(Na)]×100 It is calculated according to the formula, and IN2 is: IN2=[(Mg)+(Na)] / [(Ca)+(K)]×100, It is calculated according to the following, and in both formulas, (Mg) is the concentration of magnesium ions (mg / 1 kg of silica sample) divided by the atomic weight of magnesium (24 g / mol); (K) is the concentration of potassium ions (mg / 1 kg of silica sample) divided by the atomic weight of potassium (39 g / mol); (Ca) is the concentration of calcium ions (mg / 1 kg of silica sample) divided by the atomic weight of calcium (40 g / mol); The method according to claim 1, wherein (Na) is the concentration of sodium ions (mg / 1 kg of silica sample) divided by the atomic weight of sodium (23 g / mol).
10. The method according to claim 1, wherein the silica filler has a potassium content of more than 100 mg per 1 kg of silica sample, a magnesium content of more than 100 mg per 1 kg of silica sample, or both.
11. The method according to claim 1, wherein the silica filler is present in a weight ratio of 5:1 to 1:5, preferably 2:1 to 1:2, relative to the conjugated diene polymer.
12. The method according to claim 1, further comprising the step of combining the conjugated diene polymer and the silica filler with at least one curing agent.
13. A rubber compound obtained by the method described in any one of claims 1 to 12.
14. An article obtained by a process comprising a step of curing the rubber compound according to claim 13, wherein the process comprises at least one molding step, the molding step may be performed before, during, or after the curing.
15. The article according to claim 14, selected from tire tread or tire.