Rubber compound of functionalized conjugated diene rubber and silica filler

Abstract

A rubber compound comprising 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 comprising rice husk ash, and wherein the conjugated diene polymer is a homopolymer of conjugated dienes or at least one copolymer of conjugated dienes selected from the group consisting of butadiene, isoprene, 1, 3-pentadiene, 2, 3-dimethylbutadiene, 1-phenyl-1, 3-butadiene, 1, 3-hexadiene, and at least one of the conjugated dienes selected from the group consisting of butadiene, isoprene, 1, 3-pentadiene, 2, 3-dimethylbutadiene, 1-phenyl-1, 3-butadiene, and 1, 3-hexadiene, and wherein the polymer is functionalized and comprises at least one functional group. Also provided is a method of making a vulcanizable rubber compound comprising combining the conjugated diene polymer with the silica, and a method of making an article comprising subjecting a curable composition comprising the compound and a curing agent capable of curing the conjugated diene polymer to at least one curing reaction. Further provided are articles obtained from these compounds.

Description

Background Art

[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 molded into articles or combined with other ingredients to produce articles. Major applications of synthetic rubbers include tires or parts of tires, such as tire treads. Typically, conjugated diene rubbers are homopolymers of conjugated dienes or copolymers of at least one conjugated diene monomer used for this purpose.

[0002] There is a continuing need to improve the properties of tires and in particular the properties of tire treads. It has now been found that a combination of a conjugated diene rubber functionalized to contain at least functional groups and a specific silica filler can be advantageously used to make rubber compounds for producing tires or tire treads. Summary of the invention

[0003] Thus, in one aspect, there is provided a method for producing rubber, the method comprising combining a conjugated diene polymer and a silica filler, wherein the silica filler has an SiO2 content of at least 80% by weight based on the weight of the filler and is obtained from biomass ash comprising rice husk ash, and wherein 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 wherein the polymer is functionalized and comprises at least one functional group comprising at least one polar group selected from the group consisting of: -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, R'1 and R'2 independently represent H, a C1-C6 alkyl group, or a -Si(R'4)(R'5) group, wherein R'4 and R'5 independently represent a C1-C6 alkyl group.

[0004] In another aspect, a rubber compound obtained by the method is provided.

[0005] In a further aspect, a method of making an article is provided, the method comprising subjecting a curable composition comprising a compound and a curing agent capable of curing a conjugated diene polymer to at least one curing reaction.

[0006] In another aspect, an article is provided, which is obtained by a method comprising curing a composition comprising a compound, wherein the method comprises at least one shaping step, wherein the shaping can be performed before, during or after curing. DETAILED DESCRIPTION

[0007] In the following description, the terms "comprising", "containing", "including", "having" are intended to have an open meaning, thereby allowing, for example, the presence of additional ingredients, components, steps or procedures. For example, a composition "comprising ingredient X" is meant to describe a composition that includes ingredient X but optionally includes additional ingredients other than ingredient X. For a closed meaning, the term "consisting of..." is used. A composition "consisting of ingredient X" is meant to include ingredient X but no other ingredients.

[0008] In the following description, the specification may be used. If not otherwise stated, the specification is used in the version valid on March 1, 2020. If there is no version valid on that date, for example because the specification has expired, reference is made to the version valid on the date closest to March 1, 2020.

[0009] In the following description, the amount of a component of a composition or polymer may be expressed interchangeably by "weight percent," "wt. %," or "% by weight." Unless otherwise indicated, the terms "weight percent," "wt. %," or "% by weight" are based on the total weight of the composition or polymer, respectively, which is 100%.

[0010] The term "phr" means parts per hundred parts of rubber, ie, the weight percent based on the total amount of rubber set at 100.

[0011] Unless otherwise stated, ranges identified in this disclosure include and disclose all values ​​between and including the endpoints of the range.

[0012] The term "substituted" is used to describe a hydrocarbon-containing organic compound in which at least one hydrogen atom has been replaced by a chemical entity other than hydrogen. The chemical entity is referred to interchangeably herein as a "substituent," "residue," or "group." For example, the term "methyl substituted by fluorine" refers to a fluorinated methyl group and includes the groups -CF3, -CHF2, and -CH2F. The term "unsubstituted" is intended to describe a hydrocarbon-containing organic compound in which none of its hydrogen atoms have been replaced. For example, the term "unsubstituted methyl residue" refers to a methyl group, i.e., -CH3.

[0013] Conjugated diene polymers

[0014] The conjugated diene polymer according to the present disclosure can be obtained by a polymerization reaction, which includes polymerizing at least one conjugated diene as a monomer. Preferably, the diene polymer is a homopolymer or copolymer of at least one conjugated diene, and the at least one conjugated diene is 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.

[0015] In one embodiment of the present disclosure, the diene polymer is a polybutadiene homopolymer, more preferably a 1,3-butadiene homopolymer. In another embodiment of the present disclosure, the diene polymer is a 1,3-butadiene copolymer.

[0016] In another embodiment 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 conjugated dienes as described above 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, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-tert-butylstyrene, vinylnaphthalene and combinations thereof. Styrene is particularly preferred.

[0017] Vinyl aromatic monomers also include substituted vinyl aromatic monomers, wherein one or more hydrogen atoms of the vinyl aromatic monomer are replaced by heteroatoms or groups with one or more heteroatoms, and these heteroatoms are preferably selected from Si, N, O, H, Cl, F, Br, S and combinations thereof. Substituted monomers also include vinyl aromatic monomers, and these monomers have one or more functional groups with one or more heteroatoms or contain at least one unit with one or more heteroatomic functional groups. Preferably, heteroatoms are selected from Si, N, O, H, Cl, F, Br, S and combinations thereof. Examples of functional groups include, but are not limited to, hydroxyl, thiol, thioether, ether, halogen, carboxylic acid group or its salt, and combinations thereof. Such functionalized conjugated monomers are preferably copolymerized with one or more of the vinyl aromatic monomers described above.

[0018] In preferred embodiments, the diene polymer according to the present disclosure comprises repeating units derived from 1,3-butadiene and styrene.

[0019] Preferably, the polymer according to the present disclosure contains at least 50% by weight, preferably at least 60% by weight, of units derived from 1,3-butadiene, based on the weight of the polymer. In one embodiment of the present disclosure, the diene polymer contains at least 60% by weight or at least 75% by weight of units derived from 1,3-butadiene. In one embodiment, the polymer according to the present disclosure comprises at least 75% or at least 95% by weight of units derived from one or more than one conjugated diene monomer.

[0020] In one embodiment of the present disclosure, the diene polymer contains 0 to 49% by weight or 0 to 40% by weight of units derived from one or more comonomers, based on the total weight of the polymer.

[0021] In one embodiment, the diene polymer of the present disclosure contains 0 to 20% by weight of units derived from one or more conjugated dienes other than 1,3-butadiene.

[0022] In one embodiment, the diene polymer according to the present disclosure contains at least 50% by weight, preferably at least 60% by weight, of units derived from 1,3-butadiene and at least 5% by weight, and preferably up to 49% by weight of units derived from one or more vinyl aromatic comonomers, preferably 5% to 40% by weight, or 10% to 35% by weight of units derived from one or more vinyl aromatic comonomers, preferably styrene, based on the weight of the polymer. Alternatively, such polymers may contain 0% to 25% by weight 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 contains 55% to 92% by weight of units derived from one or more conjugated diene monomers and 5.8% to 45% by weight of units derived from vinyl aromatic comonomers.

[0023] Suitable other conjugated dienes as comonomers include but are not limited to myrcene, ocimene and / or farnesene.Conjugated dienes also include substituted conjugated dienes, wherein one or more hydrogen atoms of the diene are replaced by heteroatomic groups containing one or more selected from Si, N, O, H, Cl, F, Br, S and combinations thereof or containing one or more heteroatomic functional groups (for example, with one or more selected from Si, N, O, H, Cl, F, Br, S and combinations thereof).The example of functional group includes but is not limited to hydroxyl, thiol, thioether, ether, halogen, amine, silane and units with one or more carboxylic acid groups or their salts, and combinations thereof.This type of functionalized conjugated diene is preferably copolymerized with one or more of the conjugated dienes described above.

[0024] Suitable copolymerizable comonomers further include one or more α-olefins, such as ethylene, propylene, 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 0% to 20% by weight of units derived from one or more α-olefins.

[0025] Suitable comonomers also include, but are not limited to, one or more other copolymerizable comonomers other than the above functional comonomers, which introduce functional groups including crosslinking sites, branching sites, side chains or functionalized groups. In one embodiment of the present disclosure, the diene polymer contains 0% to 10% by weight or 0% to 5% by weight of units derived from one or more such other comonomers. Such comonomers include, for example, divinylbenzene, trivinylbenzene, divinylnaphthalene.

[0026] Combinations of one or more comonomers of the same chemical type as described above as well as combinations of one or more comonomers from different chemical types can be used. In one embodiment of the present disclosure, there are no other comonomers described above, or the polymer contains less than 10% by weight, less than 5% by weight, or no more than 1% by weight of units derived from them.

[0027] Butadiene and some or all of the other monomers used to produce the polymer according to the present disclosure can be obtained from fossil resources or from sustainable resources. Sustainable resources include renewable materials, including plant-based materials or materials produced by organisms (including fungi, microorganisms and extremophiles) or enzymes, in which case the monomers are also referred to as "bio-based monomers". Sustainable resources also include recycled materials, in which case they are products certified by ISCC+, for example. Recycled materials can include recycled plant-based materials and recycled non-plant-based materials, such as materials obtained from the conversion of plastic waste or rubber waste (including pyrolysis of tires). The chemical and mechanical properties of polymers obtained from materials obtained from sustainable resources are no different from those of polymers obtained from materials from fossil resources. The physical properties of polymers are also the same, except that monomers obtained from plant-based materials can have different amounts of carbon 14 isotopes from monomers obtained from fossil resources. However, the use of monomers from sustainable resources can increase the biocontent of polymers and reduce the carbon dioxide footprint of polymers in any case, and therefore contribute to reducing carbon dioxide generation. Although monomers obtained from sustainable resources can replace monomers from fossil sources, using monomers obtained from sustainable resources may require additional purification steps to remove impurities from their production process. Such purification methods are known to those skilled in the art and include, but are not limited to, distillation, absorption on resins or other absorbents, and combinations thereof.

[0028] The diene polymer according to the present disclosure preferably has 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.

[0029] Preferably, the diene polymer according to the present disclosure has a glass transition temperature (Tg) of about -110°C to about +20°C, preferably about -110°C to about 0°C.

[0030] Preferably, the diene polymer according to the present disclosure has a Mooney viscosity [ML 1+4 (100° C.)] of about 10 to about 200, preferably about 30 to about 150 Mooney units.

[0031] The polymers typically have a dispersity of about 1.03 to about 3.5.

[0032] Diene polymers can be prepared by methods known in the art. Preferably, the polymer can be obtained by a method comprising anionic solution polymerization or polymerization using one or more coordination catalysts. The polymerization can be carried out in solution or in the gas phase. Coordination catalysts include Ziegler-Natta catalysts or monometallic catalyst systems. Preferred coordination catalysts are those based on Ni, Co, Ti, Zr, Nd, V, Cr, Mo, W or Fe.

[0033] Conjugated diene polymers are functionalized. Functionalized conjugated diene polymers can be prepared, for example, by involving the following reaction: at least one functionalizing agent is added to a reactive polymer chain produced by polymerization of a conjugated monomer, and at least one additional functionalizing agent as known in the art can be subsequently added. In one embodiment, the at least one functional group is produced by a coupling agent designed to additionally produce at least one functional group, and the functionalized polymer is also a coupled polymer. A coupling agent can connect two or more polymer chains together via a reaction using a coupling agent. In one embodiment, the functional group has been produced by a functionalizing agent that is not a coupling agent. In one embodiment of the present disclosure, a polymer is obtained by using a coupling agent that also produces a functional group in combination with one or more functional agents simultaneously or subsequently to generate a terminal functional group. In one embodiment of the present disclosure, the polymer is a coupled polymer, wherein the coupled polymer can be produced by using a coupling agent that produces a functional group or a coupling agent that does not produce a functional group. In one embodiment, the polymer according to the present disclosure is not coupled.

[0034] Preferably, the diene polymer has been functionalized by one or more suitable functionalizing agents to produce functional groups at the ends of the polymer or as side groups or as part of a coupled polymer. Preferably, the functional group comprises 1 to 20 silicon atoms and comprises heteroatoms selected from O, N and S, optionally in addition to carbon and hydrogen atoms. Preferably, the polymer has been functionalized to have at least one terminal functional group, which may be located at the α position or ω position of the polymer or both. Preferably, the functional group comprises 1 to 50 carbon atoms, more preferably, the functional group comprises 1 to 12 silicon atoms and 1 to 30 carbon atoms and may optionally further comprise one or more heteroatoms selected from S and N or a combination thereof.

[0035] Preferably, the functional group comprises at least one group selected from the following formula

[0036] *-Si(R 1 )(R 2 )-C(R 3 )(R 4 )-,*-Si(R 1 )(R 2 )-O-Si(R 3 )(R 4 )-, or a combination thereof

[0037] Where R 1 , R 2 , R 3 , R 4 the same or different and selected from H and optionally containing a heteroatom selected from O, N, S and Si C1-C 12 Alkyl, for example, as alkoxy, trialkylsilyl, alkylamino, dialkylamino and combinations thereof, and wherein *- represents a bond to the polymer chain, and wherein R 1 and R 2 At least one of may also represent a chain of a polymer.

[0038] Preferably, the functional group further comprises at least one polar group selected from the following: -OX, -OR, -COOX, -COOR, -SX, -N(R'1)(R'2) or a combination thereof, wherein X represents H or a cation, R represents a C1-C6 alkyl group, R'1 and R'2 independently represent H, a C1-C6 alkyl group, -Si(R'4)(R'5) - wherein R'4 and R'5 independently represent a C1-C6 alkyl group. More preferably, the functional group comprises at least one polar group that can be converted into an ionic group or exists as an ionic group. Preferred examples include -COOX, -N(R'1)(R'2) groups and combinations thereof.

[0039] In one embodiment, the functional group comprises at least one silyl, silanol or siloxane group selected from: -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 , in which X is a halogen, x is the number of repeating units between 1 and 30, m is the number of attached groups varying from 0 to 3, R1 and R2 are identical or different and can be linear or branched alkoxy or alkyl, cycloalkyl, aryl, alkaryl, aralkyl or vinyl having in each case 1 to 20 carbon atoms, and R3 is H or linear or branched alkyl, or mononuclear aryl having in each case 1 to 20 carbon atoms.

[0040] In one embodiment, the functional group comprises or consists of a group represented by the formula

[0041] -[-Si(R1R2)-O-] n -Si(R1R2)-OH,

[0042] wherein R1 and R2 are identical or different and may be linear or branched alkoxy or alkyl, cycloalkyl, aryl, alkaryl, aralkyl or vinyl radicals having in each case 1 to 20 carbon atoms, and n represents the number of siloxane-functional units preceding the silanol end groups varying from 1 to 49, preferably from 1 to 29.

[0043] In one embodiment, the functional group comprises or consists of a group represented by the formula:

[0044] *-Si(A 2 -N((H) k (R i ) 2-k )) y (OR i ) z (R3) 3-(y+z) ,

[0045] wherein: k may vary from 0 to 2, y may vary from 1 to 3, and z may vary from 0 to 2, 0<y+z<3, R1 and R2 are identical or different and may be linear or branched alkyl, cycloalkyl, aryl, alkaryl, aralkyl or vinyl, mononuclear aryl having in each case 1 to 20 carbon atoms, R3 is H or linear or branched alkyl having in each case 1 to 20 carbon atoms, and A2 is a spacer having up to 12 carbon atoms and may be linear or branched, and is preferably selected from alkyl, allyl or vinyl.

[0046] In one embodiment, the at least one functional group is generated by reacting the reactive polymer chain with a silane sulfide modifier as described in WO 2014 / 040639 A1 or with an aminosilane as described in EP 2675278 A1.

[0047] Preferably, the functional group comprises at least one terminal unit, which comprises at least one group selected from the following groups: -OX, -OR, -COOX, -COOR, -SX, -N(R'1)(R'2) or a combination thereof, wherein X represents H or a cation, R represents a C1-C6 alkyl group, and R'1 and R'2 independently represent H, C1-C6 alkyl group, 10 Alkyl, -Si(R'4)(R'5) group - wherein R'4 and R'5 are independently C1-C 10 In one embodiment of the present disclosure, the functional group does not contain a -SX group.

[0048] In one embodiment of the present disclosure, the second functional group can be obtained by a reaction comprising the following steps: 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 treated with a suitable reagent to obtain at least one terminal unit selected from the following: -OX, -OR, -COOX, -COOR, -SX, -N(R'1)(R'2) or a combination thereof, wherein X represents H or a cation, R represents a C1-C6 alkyl group, and R'1 and R'2 independently represent H, C1-C6 alkyl group, 20 Alkyl, -Si(R'4)(R'5) group - wherein R'4 and R'5 are independently C1-C 20 Alkyl, preferably C1-C6 alkyl.

[0049] The silicon-containing compound is preferably selected from divalent compounds having one Si atom per molecule, or divalent compounds which are open chain siloxanes having 2 to 12 silicon atoms per molecule or cyclic siloxanes having 3 to 12 silicon atoms per molecule, or combinations thereof. The remaining valencies of the silicon atoms are preferably attached to R groups, wherein each R group is independently selected from the group consisting of hydrogen, alkylcycloalkyl, arylaralkyl, alkaryl groups having up to 20 carbon atoms, wherein these groups may be hetero groups selected from alkylamines and silylamines optionally attached to a carbon chain or a carbocyclic ring. The silicon-containing compound includes cyclosiloxanes according to the formula

[0050]

[0051] Where R 5 and R 6Identical or different and each selected from H, residues having 1 to 20 carbon atoms, preferably selected from alkyl, cycloalkyl, aryl, alkaryl or aralkyl groups, wherein the group may contain one or more heteroatoms, preferably O, N, S or Si, and preferably selected from methyl. Specific examples include, but are not limited to, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane and dodecamethylcyclohexasiloxane, and mixtures of cyclosiloxanes of different ring sizes.

[0052] In one embodiment of the present disclosure, the silicon-containing compound comprises 2 to 20 unsaturated siloxane units, preferably 3 to 15 unsaturated siloxane units, more preferably 4 to 10 unsaturated siloxane units, which corresponds to the general formula (1'):

[0053]

[0054] In formula (1'), each R1 independently represents an alkenyl group 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, -CH2 CH2(CH3)CH=CH2), and each R2 independently represents a chemical bond, H, OH, an alkenyl group having 2 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms (wherein the alkyl or alkenyl chain or both may be interrupted by one or more ether oxygen atoms), or a siloxane or polysiloxane having up to 10 silicon atoms, wherein the siloxane or polysiloxane may optionally have at least one silicon atom having at least one aliphatic substituent selected from an alkyl or alkenyl group or a combination thereof. Preferably, at least one R2 represents a methyl group. Preferably, all R2 represent a methyl group or an ethyl group or a combination thereof.

[0055] In one embodiment of the present disclosure, the silicon-based compound contains at least one, preferably at least two, and more preferably at least three units corresponding to the general formula (2'):

[0056]

[0057] wherein R corresponds to R2 in the above formula (1'), i.e. R is selected from an alkyl group having 1 to 10 carbon atoms, and it may optionally contain one or more oxygen-ether atoms, and may be an alkoxy or polyalkoxy residue, or may optionally contain one or more silane groups, siloxane groups or polysiloxane groups, wherein the polysiloxane or siloxane group may contain 1 to 3 alkyl or alkenyl residues on the silicon atom, and the maximum number of silicon atoms is preferably less than 10. Preferably, R is C1-C 10 -alkyl, more preferably C1-C7-alkyl, and most preferably R is methyl.

[0058] In another preferred embodiment of the present disclosure, the silicon-containing compound is cyclic and corresponds to formula (3'):

[0059]

[0060] wherein n is 1, 2, 3 or 4, preferably n is 1 or 2, and each R1 is as described in formula (1), and preferably at least one, more preferably all R1 represent vinyl (-CH=CH2). Each R2 is as described in formula (1) above. Preferably at least one R2 is C1-C7-alkyl, and more preferably at least one R2 is methyl. Most preferably all R2 represent methyl.

[0061] In one embodiment of the present disclosure, the unsaturated siloxane coupling agent corresponds to the general formula (4'):

[0062]

[0063] wherein n is an integer from 1 to 20 and m is an integer from 1 to 20, and each residue R is selected independently of one another and as described above for formula (2), and

[0064] R3 is H, OH, a saturated or unsaturated hydrocarbon having 1 to 10 carbon atoms, a monovalent siloxane, polysiloxane or silane, or R3 is linked to R5 to form a cyclic compound, and represents a divalent siloxane or polysiloxane having 1 to 10 silicon atoms, and one or at least one of the silicon atoms carries one or more alkyl or alkenyl residues having 1 to 10 carbon atoms, or R3 and R5 together form a chemical bond to form a cyclic compound, and

[0065] R4 is a linking group selected from the group consisting of: (i) an aliphatic hydrocarbon having 1 to 20 carbon atoms, which may optionally contain one or more oxygen ether groups, (ii) one or more silane or siloxane groups or combinations thereof, in which one or more than one silicon atom may carry one or more aliphatic hydrocarbon groups having 1 to 10 carbon atoms, or a combination of (I) and (II), and

[0066] R5 is H, OH, a saturated or unsaturated hydrocarbon having 1 to 10 carbon atoms, a monovalent siloxane, a polysiloxane or a silane, or R5 is connected to R3 to form a cyclic compound and represents a divalent siloxane or a polysiloxane having 1 to 10 silicon atoms, wherein one or at least one of the silicon atoms carries one or more alkyl or alkenyl residues having 1 to 10 carbon atoms, or R5 is connected to R3 to form a cyclic compound and represents a divalent siloxane or a polysiloxane having 1 to 10 silicon atoms, wherein one or at least one of the silicon atoms carries one or more alkyl or alkenyl residues having 1 to 10 carbon atoms, or R3 and R5 together form a chemical bond to form a cyclic compound.

[0067] In another embodiment of the present disclosure, the silicon-containing compound corresponds to formula (5'):

[0068]

[0069] In formula (5'), Ra, Rb, Rc, Rd, Re, Rf, Rg and Rh are the same as or different from each other and are independently selected from C1-C 10 -alkyl, C2-C6-alkenyl, -O-Si-(R 1’ R 2’ R 3’ ), wherein R1', R2' and R3' are independently selected from C1-C 10 -alkyl, C2-C6-alkenyl, preferably vinyl, preferably at least one of R1', R2' and R3' comprises a vinyl unit, preferably all R1', R2' and R'3 are vinyl (-CH=CH2). At least one, preferably at least two, more preferably at least three of Ra, Rb, Rc, Rd, Re, Rf, Rg and Rh comprise a 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, Ra-Rh are all vinyl. Compounds according to formula (5') are also referred to as polyhedral oligomeric silsesquioxanes or POSS. The materials are commercially available or can be prepared as described, for example, by Quirk, Cheng et al. in Macromolecules [macromolecules] 2012, 45, 21, 8571-8579.

[0070] Preferably, the coupling agent according to the present disclosure has a molecular weight up to and including 5000 g / mol. Preferably the coupling agent has a molecular weight less than 2000 g / mol.

[0071] Particularly preferred examples of coupling agents according to the present disclosure include

[0072] (1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane),

[0073] (1,3,5-trivinyl, 1,3,5-trimethylcyclotrisiloxane),

[0074] (octavinylsilsesquioxane),

[0075] (Substituted silsesquioxanes) wherein the residues Rb to Rg independently represent C1-C7-alkyl, preferably cyclopentyl, and Ra is -O-Si(-CH=CH2)3. Combinations of one or more coupling agents according to the present disclosure may also be used.

[0076] Silicon-containing compounds also include compounds that contain, in addition to Si and O atoms, at least one N atom of an amino group or at least one S atom of a thiol group, or a combination thereof. The amino and thiol functional groups can be protected, for example, by silyl groups and can be deprotected during post-processing or compounding. Specific examples include compounds according to the formula

[0077]

[0078] Homologues of these specific examples can also be used. Homologues include, but are not limited to, corresponding compounds in which the propene group has been replaced by another alkylene group, including, for example, a C2 alkylene group, a linear or branched C4-C10 alkylene group; or in addition or alternatively, in which one or more methyl groups have been replaced independently of one another by another linear or branched C2-C8, preferably C2-C4 alkyl group; or in which one or more ethyl groups have been replaced by C1 or a linear or branched C3-C8 alkyl group, preferably a C3-C6 alkyl group.

[0079] In one embodiment, the conjugated diene has been functionalized by a reaction involving the addition of a cyclic urea as a functionalizing agent. The cyclic urea preferably corresponds to the general formula

[0080]

[0081] R1 is selected from the group consisting of: C1-C6-alkylene which may be saturated (which is preferred) or unsaturated and may be unsubstituted or substituted by one or more substituents, C6-C 11Arylene, wherein the substituent is selected from alkoxy and oxyalkyl with 1 to 6 carbon atoms and -SiO(Rx)3 groups, wherein each Rx independently represents an alkyl with 1 to 6 carbon atoms. Preferably, R1 is C1-C3 alkylene, preferably unsubstituted, and more preferably R1 is -CH2CH2-. R2, R3 are identical or different and represent a saturated or unsaturated organic group with 1 to 24 carbon atoms, and these organic groups may contain one or more heteroatoms independently selected from the group consisting of O, N, S and Si in addition to hydrogen. For example, R2 and R3 may be selected from the group consisting of:

[0082] (i)-C1-C 24 - alkyl, saturated or unsaturated, unsubstituted, monosubstituted or polysubstituted; or

[0083] (ii) -C1-C 24 - heteroalkyl, saturated or unsaturated, unsubstituted, monosubstituted or polysubstituted;

[0084] (iii) 6- to 24-membered aryl, unsubstituted, monosubstituted or polysubstituted, wherein the 6- to 24-membered aryl is optionally linked via -C1-C6-alkylene- or -C1-C6-heteroalkylene-, in each case saturated or unsaturated, unsubstituted, monosubstituted or polysubstituted;

[0085] (iv) 5-24 membered heteroaryl, unsubstituted, monosubstituted or polysubstituted; wherein the 5-24 membered heteroaryl is optionally linked via -C1-C6-alkylene- or -C1-C6-heteroalkylene-, in each case saturated or unsaturated, unsubstituted, monosubstituted or polysubstituted;

[0086] (v) 3-24 membered cycloalkyl, saturated or unsaturated, unsubstituted, monosubstituted or polysubstituted; wherein the 3-24 membered cycloalkyl is optionally linked via -C1-C6-alkylene- or -C1-C6-heteroalkylene-, in each case saturated or unsaturated, unsubstituted, monosubstituted or polysubstituted; and

[0087] (vi) 3-24-membered heterocycloalkyl, saturated or unsaturated, unsubstituted, monosubstituted or polysubstituted; wherein the 3-24-membered heterocycloalkyl is optionally linked via -C1-C6-alkylene- or -C1-C6-heteroalkylene-, in each case saturated or unsaturated, unsubstituted, monosubstituted or polysubstituted, wherein "monosubstituted or polysubstituted" in each case means substituted by one or more independently selected from C1-C6-alkylene groups which may be saturated or unsaturated. 18 -alkyl and tri(C1-C 18Preferably, R2 and R3 are selected from C1-C6-alkyl, more preferably from -CH3 or -CH2CH3.

[0088] The reaction product can be treated with an appropriate reagent to introduce terminal units, such as at least one terminal unit selected from the following: -OX, -OR, -COOX, -COOR, -SX, -N(R'1)(R'2) or a combination thereof, wherein X represents H or a cation, R represents a C1-C6 alkyl group, and R'1 and R'2 independently represent H, C1-C6 alkyl group, 10 Alkyl, -Si(R'4)(R'5) group - wherein R'4 and R'5 are independently C1-C 10 Alkyl. Suitable reagents include, but are not limited to, acids, alcohols, thiols, and combinations thereof. Carboxylic acid groups can be introduced, for example, by treatment with a silyl lactone-based functionalizing agent or an anhydride-based reagent. Treatment with a silyl lactone-based or anhydride-based treatment can also be carried out by direct reaction with a reactive polymer chain. Functionalization of polymers is described, for example, in WO2021 / 009154; US 3,242,129, US4,020,036, US 4,465,809, US2016 / 0075809A1 and US2016 / 0083495A1 and WO2021 / 009154, all of which are incorporated herein by reference.

[0089] Amino-functionalized initiators can be used for terminal groups having at least one amino functional group at the alpha position of the polymer. Examples of suitable amino-functionalized initiators include 1-naphthyl lithium; allyl lithium compounds derived from tertiary N-allyl amines, 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; amide lithiums of secondary amines, such as pyrrolidine lithium, piperidine lithium, hexamethyleneimine lithium, 1-methylimidazole amide lithium, 1-methylpiperazine lithium, morpholine lithium, dicyclohexyl amide lithium, dibenzyl amide lithium, diphenyl amide lithium. These allyl lithium compounds and these amide lithiums can also be prepared in situ by reaction of an organic lithium compound with a corresponding tertiary N-allyl amine or with a corresponding secondary amine. Amine-functionalized monomers can also be used to generate amino-functionalized groups at the alpha position of the polymer. They can be added before polymerization or at the beginning and / or during polymerization rather than at the end of polymerization. Amine functional monomers can also be added as active reaction products comprising at least two repeating units derived from functionalized monomers. Such active reaction products can be produced by the reaction of one or more amine functional monomers and organometallic compounds (for example, initiators for anionic polymerization as described above), preferably organolithium compounds, preferably alkyl lithiums and more preferably butyl lithium. Reaction can include the oligomerization of amine functional monomers, or the co-oligomerization of amine functional monomers and one or more other comonomers (for example, conjugated dienes, as described above). Oligomerization or co-oligomerization can result in oligomeric functional monomers with 2 to 200 units derived from amine functional monomers. Active reaction products as mentioned herein mean that monomers have complete carbon-carbon double bonds that can participate in polyreaction or negative carbon ions that can participate in polyreaction or both. The reaction product can be produced in a separate reaction and then added to the polymerization reactor, or it can be formed in situ, such as by co-feeding one or more amine-functional monomers and a reaction initiator to the polymerization reaction, or by first reacting the initiator and amine-functional monomer before adding the conjugated diene monomer.

[0090] Examples of amine functional monomers include, but are not limited to, those corresponding to formula (1"):

[0091]

[0092] wherein R1, R2, R3 are selected from hydrogen and methyl, provided that at least one of R1, R2 and R3 is hydrogen, preferably R1, R2 and R3 are all hydrogen,

[0093] n is 1, 2, 3, 4, or 5,

[0094] Each R4 is independently selected from aliphatic or arylaliphatic residues having 3 to 30 carbon atoms, and wherein if n is 1, R4 comprises at least one tertiary amine group, and in the case where n is 2 to 5, at least one of the residues R4 comprises at least one tertiary alkylamine group. In one embodiment of the present disclosure, R4 is selected from the formula (2")

[0095]

[0096] and a group represented by formula (3")

[0097]

[0098] Wherein in formula (2"), R5 is selected from the group consisting of: a chemical bond, an unsubstituted or substituted straight or branched alkylene group having 1 to 20 carbon atoms, an unsubstituted or substituted cycloalkylene group having 5 to 20 carbon atoms; or an unsubstituted or substituted arylene group having 6 to 20 carbon atoms, wherein the substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and R6 and R7 are each independently a cycloalkyl group having 5 to 10 carbon atoms, or an unsubstituted or substituted aryl group having 6 to 20 carbon atoms. R8 is hydrogen; an alkyl group having 1 to 30 carbon atoms; an alkenyl group having 2 to 30 carbon atoms; an alkynyl group having 2 to 30 carbon atoms; a heteroalkyl group having 1 to 30 carbon atoms; a heteroalkenyl group having 2 to 30 carbon atoms; a heteroalkynyl group having 2 to 30 carbon atoms; a cycloalkyl group having 5 to 30 carbon atoms; an aryl group having 6 to 30 carbon atoms; or a heterocyclyl group having 3 to 30 carbon atoms, and X is a chemical bond or a N, O or S atom, in which case X is O or S or a chemical bond, R8 is absent,

[0099] Wherein in formula (3"), R9 is an unsubstituted or substituted alkylene group having 1 to 20 carbon atoms, an unsubstituted or substituted cycloalkylene group having 5 to 20 carbon atoms; or an unsubstituted or substituted arylene group having 6 to 20 carbon atoms, wherein the substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and R 11 and R 12 Each is independently an alkyl group having 1 to 30 carbon atoms; an alkenyl group having 2 to 30 carbon atoms; an alkynyl group having 2 to 30 carbon atoms; a heteroalkyl group having 1 to 30 carbon atoms; a heteroalkenyl group having 2 to 30 carbon atoms; a heteroalkynyl group having 2 to 30 carbon atoms; a cycloalkyl group having 5 to 30 carbon atoms; an aryl group having 6 to 30 carbon atoms; or a heterocyclyl group having 3 to 30 carbon atoms.

[0100] Specific examples include but are not limited to:

[0101] 4-(2-(N,N-bis(trimethylsilyl)amino)ethyl)styrene

[0102]

[0103] Vinylbenzylpyrrolidine,

[0104]

[0105] and N,N-dimethylaminomethylstyrene

[0106]

[0107] The conjugated diene polymers can be oil-extended and can contain up to 100 parts of extender oil per 100 parts of polymer. In the case where the polymer is oil-extended, i.e., before or during post-processing of the polymer, typically before solvent removal, the polymer has been combined with one or more extender oils, then the composition also contains the extender oil as part of the oil-extended polymer. When the polymers have a high molecular weight, they can be oil-extended. Polymers with high molecular weight have a high Mooney viscosity. When the Mooney viscosity is too high, processing the polymer to make a rubber compound may become difficult or uneconomical. The Mooney viscosity of the polymer can be reduced by adding an extender oil before or during post-processing of the polymer to provide an oil-extended polymer. The typical amount of extender oil is 10 to 100 parts per 100 parts of polymer. Extender oils include oils known and used for diene rubber extension and include oils 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 their hydrogenated forms, including oils obtained from plant-based materials, including terpenes. They are preferably added to the reaction mixture before or during solvent removal.

[0108] Silica Filler

[0109] The silica filler according to the present disclosure is preferably precipitated silica. Precipitated silica is obtained by acidifying a caustic silicate solution to produce a slurry of precipitated silica. Mineral acids (e.g., sulfuric acid) may be used for precipitation. The precipitated silica is separated from the slurry, dried and optionally ground to a desired particle size. Precipitated silica is typically a powder.

[0110] In conventional methods for producing precipitated silica, a caustic silicate solution is prepared 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 methods, a caustic silicate solution is prepared by caustic digestion of biomass ash (like rice husk) containing silica. The ash is obtained by pyrolysis of biomass. Methods for preparing precipitated silica are described, for example, in US6375735 B1 and the references cited therein.

[0111] It has now been found 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 tire compounds 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 calculated according to the following formula:

[0112] IN1=[(Mg)+(K)] / [(Ca)+(Na)]×100.

[0113] The ion number IN2 is calculated according to the following formula:

[0114] IN2=[(Mg)+(Na)] / [(Ca)+(K)]×100.

[0115] In these two formulas:

[0116] (Mg) is the magnesium ion concentration in the silica sample (in mg / kg) divided by the atomic weight of magnesium (24 g / mol), i.e. c(Mg 2+ ) / 24 g / mol;

[0117] (K) is the potassium ion concentration in the silica sample (in mg / kg) divided by the atomic weight of potassium (39 g / mol), that is, c(K + ) / 39g / mol;

[0118] (Ca) is the calcium ion concentration in the silica sample (in mg / kg) divided by the atomic weight of calcium (40 g / mol);

[0119] (Na) is the sodium ion concentration in the silica sample (in mg / kg) divided by the atomic weight of sodium (23 g / mol).

[0120] Preferably, the silica filler has a potassium content greater than 100 mg / kg silica sample, a magnesium content greater than 100 mg / kg silica sample, or both.

[0121] It is believed that the silica obtained from biomass ash, especially rice husk ash, has 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 produce the above-mentioned cationic characteristics.

[0122] The silica filler according to the present disclosure is preferably precipitated silica obtained from biomass ash, preferably from biomass ash containing rice husk ash. Preferably, the filler is obtained by a process comprising caustic digestion of biomass ash, preferably rice husk ash. The ash is preferably obtained from pyrolysis of biomass. Preferably, the caustic silicate solution is acidified, preferably by at least one inorganic acid, to produce a slurry of precipitated silica, and the process further comprises separating the precipitated silica from the slurry.

[0123] 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 to 300 m2 / g or 30 to less than 190 m2 / g.

[0124] Fillers according to the present disclosure may be used with functionalized polymers according to the present disclosure in a weight ratio of silica to polymer of 5:1 to 1:5, preferably 2:1 to 1:2.

[0125] The silica filler according to the present disclosure can be used alone or in a mixture with other silica fillers or with one or more fillers that are not silica fillers. In one embodiment of the present disclosure, the rubber composition contains a mixture of silica fillers 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 0.01: 1 to 50: 1, preferably 0.05: 1 to 20: 1. The example of a suitable carbon-based filler includes but is not limited to the carbon black produced by flame soot, channel, furnace, gas soot, heat, acetylene soot or arc method. The carbon-based filler can have a BET surface of 9-200m2 / 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-soot or carbon blacks as specified in ASTM. 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 black. Carbon-based fillers obtained from sustainable sources, such as from the recycling of rubber or plastic waste, including carbon-based materials obtained from the pyrolysis of tires, can also be used.

[0126] Examples of suitable fillers that are neither silicon-based nor carbon-based include, but are not limited to, glass fibers and glass fiber products (felt, 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; rubber gels including those based on BR, E-SBR and / or polychloroprene, preferably having a particle size of 5 nm to 1000 nm.

[0127] Other rubbers and rubber additives

[0128] The polymer and silica according to the present disclosure can be used to make a vulcanizable rubber compound by a method comprising combining the polymer and silica filler with one or more crosslinking agents for crosslinking at least a conjugated diene polymer. Therefore, in one aspect of the present disclosure, there is provided a method of making a vulcanizable rubber compound, the method comprising combining a polymer according to the present disclosure with at least one silica filler according to the present disclosure, and optionally further comprising combining at least one curing agent capable of curing the at least diene polymer or a combination thereof, and optionally combining one or more additional rubbers and / or rubber additives.

[0129] The rubber compound according to the present disclosure may further contain one or more additional rubbers and at least one rubber additive in addition to the functionalized rubber according to the present disclosure.

[0130] Other rubbers include, for example, natural rubber and synthetic rubber. If present, based on the total amount of rubber in the composition, they can be used in an amount ranging from 0.5% to 95% by weight, preferably ranging from 10% to 80% by weight. 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 hydrogenated or fully hydrogenated NBR rubber), EPDM (ethylene-propylene-diene terpolymer), and mixtures thereof. Of particular interest for use in the manufacture of automobile tires are natural rubber, E-SBR and S-SBR having a glass transition temperature above -60°C, polybutadiene rubber with a high cis content (>90%) produced using catalysts based on Ni, Co, Ti or Nd, polybutadiene rubber with a vinyl content up to 80%, and mixtures thereof.

[0131] Rubber additives are the processing characteristics that can improve rubber composition, be used for crosslinking rubber composition, improve the physical characteristics of the vulcanized product produced by rubber, improve the interaction between rubber and filler or be used for rubber to be bonded to the composition of filler.Rubber additives include crosslinking agent (such as sulphur or sulphur supply compound), reaction accelerator, antioxidant, heat stabilizer, light stabilizer, ozone stabilizer, processing aid, plasticizer, tackifier, foaming agent, dye, pigment, wax, filler, organic acid, silane, retarder, metal oxide, filling oil (such as DAE (distillate aromatic extract)-, TDAE (treated distillate aromatic extract)-, MES (mild extract solvate)-, RAE (residual aromatic extract)-, TRAE (treated residual aromatic extract)-, cycloparaffin oil and heavy cycloparaffin oil) and activator.The oil obtained by sustainable source (comprising renewable source or recycled material) can also be used.The oil obtained by renewable source includes the oil obtained by plant (comprising vegetable oil), or by microorganism or by enzyme production.

[0132] The total amount of additional rubber and rubber additives may 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.

[0133] Examples of typical formulations for rubber compounds include those shown in US 2016 / 0075809 A1 and US 2016 / 0083495 A1 (Steinhauser and Gross) and International Patent Application WO 2021 / 009154 (Steinhauser).

[0134] The rubber composition can be prepared with conventional processing equipment for manufacturing and processing (vulcanizable) rubber compounds, and includes rollers, kneading machines, internal mixers or mixing extruders. The rubber composition can be produced in a single stage or multi-stage process, preferably in 2 to 3 mixing stages. Cross-linking agents (such as sulfur) and accelerators can be added in a separate mixing stage, such as on a roller, preferably at a temperature within the range of 30°C to 90°C. Cross-linking agents (such as sulfur) and accelerators are preferably added in the final mixing stage.

[0135] application

[0136] The vulcanizable rubber compound may be subjected to at least one curing reaction to produce a shaped article.The shaped article contains the compound or at least the conjugated diene polymer in vulcanized (ie crosslinked) form.

[0137] Therefore, in one aspect, there is provided an article obtained by curing the rubber compound according to the present disclosure. The method may comprise at least one molding step, wherein the molding may be performed before, during or after curing. Preferably, the rubber compound according to the present disclosure is used to manufacture a tire or a tire tread, and preferred articles include tires, preferably tire treads. However, the rubber compound provided herein is also suitable for the manufacture of other articles, in particular other molded articles, for example, for the manufacture of cable sheaths, hoses, transmission belts, conveyor belts, roller linings, shoe soles, sealing rings and damping elements.

[0138] The following examples are provided to further illustrate the present disclosure but are not intended to limit the present disclosure to the embodiments set forth in these examples.

[0139] method

[0140] Composition of silica samples

[0141] The composition of the silica samples was determined by X-ray fluorescence (XRF).

[0142] To determine the cationic content of the cations used to calculate the ion number, 0.5 g of a silica sample was digested by dry ashing in a platinum crucible at 550° C. and the ash was subsequently distilled in hydrochloric acid. After appropriate dilution of the digested solution with deionized water, the metal content was measured by ICP-OES (Inductively Coupled Plasma-Optical Emission Spectroscopy) at the following wavelengths:

[0143] Calcium: 317.933nm,

[0144] Magnesium: 285,213nm,

[0145] Potassium: 766.491nm,

[0146] Sodium: 589.592nm

[0147] The reference is a calibration solution matched to the acid matrix. Depending on the concentration of the elements in the digestion solution and the sensitivity of the measuring instrument used, the concentration of the sample solution is matched to the linear region of the calibration at the wavelength used in each case. The BET surface area can be determined using nitrogen according to ISO 9277 or ISO 18852.

[0148] Number of ions:

[0149] The ion number 1 (IN1) is calculated according to formula (1):

[0150] IN1=[(Mg)+(K)] / [(Ca)+(Na)]×100.

[0151] The ion number 2 (IN2) is calculated according to formula (2):

[0152] IN2=[(Mg)+(Na)] / [(Ca)+(K)]×100.

[0153] In formula 1 and 2:

[0154] (Mg) is the magnesium ion concentration in the silica sample (in mg / kg) divided by the atomic weight of magnesium (24 g / mol), i.e. c(Mg 2+ ) / 24 g / mol;

[0155] (K) is the potassium ion concentration in the silica sample (in mg / kg) divided by the atomic weight of potassium (39 g / mol), that is, c(K + ) / 39g / mol;

[0156] (Ca) is the calcium ion concentration in the silica sample (in mg / kg) divided by the atomic weight of calcium (40 g / mol);

[0157] (Na) is the sodium ion concentration in the silica sample (in mg / kg) divided by the atomic weight of sodium (23 g / mol).

[0158] Molecular weight

[0159] The molecular weights (Mw and Mn, weight average and number average molecular weight, respectively) of the polymers were determined by gel permeation chromatography.

[0160] Properties of the vulcanized compounds

[0161] The loss factor tan δ was measured at 0° C. and at 60° C. to determine the temperature-dependent dynamic mechanical properties. An EPLEXOR device from GABO (Eplexor 500N) was used for this purpose. The measurements were carried out in the temperature range of −100° C. to 100° C. in accordance with DIN 53513 at 10 Hz on Ares tapes.

[0162] The rebound resilience at 60° C. is determined in accordance with DIN 53512.

[0163] The tensile strength tests were carried out in accordance with DIN 53504 on vulcanized S2 test specimens.

[0164] The elastic properties were determined according to DIN53513-1990. An elastomer testing system (MTS Systems GmbH, 831 elastomer testing system) was used. The measurements were carried out in double shear mode, with no static prestrain in the shear direction, and the cylindrical samples (2 samples, each 20×6 mm, pre-compressed to 5 mm thickness) were oscillated near 0, and the measurement frequency in the strain range of 0.1% to 40% was 10 Hz. This method was used to obtain the following properties:

[0165] G'(0.5%): dynamic modulus under 0.5% amplitude sweep, G'(15%): dynamic modulus under 15% amplitude sweep, G'=G'(0.5%)-G'(15%): difference in dynamic modulus under 0.5% relative to 15% amplitude sweep, tanδ(maximum): maximum loss factor (G" / G') in the entire measurement range at 60°C.

[0166] The difference of G'(0.5%) - G'(15%) is an indication of the Payne effect of the mixture. The lower the 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.

[0167] Examples C1-C4 and Ex1, Ex2 and Ex3

[0168] Conjugated diene polymers (Polymers 1 and 2) were mixed with different silicas in a tire tread formulation and subjected to curing. Polymer 1 is a non-functionalized styrene-butadiene copolymer. Polymer 2 is a styrene-butadiene copolymer of similar composition but functionalized to have terminal polar siloxane units containing carboxylate end groups. Silica 1 is a conventional precipitated silica (ULTRASIL 7000GR, surface area (N2) = 175 m2 / g). Silica 2 is a precipitated silica with a surface area of ​​165 m2 / g. 2 / g surface area (BET) of conventional precipitated silica (ZEOZIL1165 MP). Silica 3 and 4 were obtained from rice husk ash and had a surface area of ​​145-175 m 2 / g and 160+ / -10m 2 The surface area (BET) of each of the following examples is shown in Table 3. The surface area (BET) of each of the following examples is shown in Table 4. The surface area (BET) of each of the following examples is shown in Table 5. The surface area (BET) of each of the following examples is shown in Table 6. The surface area (BET) of each of the following examples is shown in Table 7. The surface area (BET) of each of the following examples is shown in Table 8. The surface area (BET) of each of the following examples is shown in Table 9.

[0169] Table 1: Composition of silica samples

[0170]

[0171]

[0172] *Repeat experiment of S3.

[0173] Table 2: Ionic number of silicon dioxide

[0174] S1 S2 S3 S3bis S4 (Ca) 7 11.75 8 7.5 22.25 (Mg) 3.3 3.2 6.7 6.3 25.0 (Na) 195.7 321.7 260.9 243.5 869.6 (K) 1.79 0.64 9.49 9.23 25.64 IN1 2.51 1.14 5.01 6.17 5.86 IN2 22.6 26.2 15.3 14.9 18.7

[0175] Table 3: Compound formulations.

[0176]

[0177]

[0178] Table 4: Compound properties

[0179]

[0180] Comparison of the compounds of non-functionalized SSBR and conventional silica with the compounds of non-functionalized SSBR and silica obtained from biomass ash (C1 and C3) shows only minor changes in energy dissipation, e.g., rebound at 60°C, tanδ(0°C) / tanδ(60°C) and reinforcement S300 / S100. In the case of C4, a trade-off between improved dynamic properties and reduced tensile properties is observed. Replacing the non-functionalized SSBR with functionalized SSBR in the compounds with conventional silica shows an improvement in dynamic properties, while the reinforcement parameters remain constant (C5, C6). The combination of functionalized SSBR with silica obtained from biomass ash (Ex1 relative to C1, C3, C5 and Ex2 relative to C4) shows further improvements in dynamic properties: a beneficial wet grip / rolling resistance balance (tan d 0°C / tan d 60°C), improved rebound at 60°C and improved filler dispersion (Payne effect). Good values ​​were also achieved in Ex3, including low values ​​for the Payne effect, which is advantageous because it shows improved dispersion with the filler. In addition, the reinforcement parameters (S300 / S100) were also improved (Ex1 vs. C1, C3, C5 and Ex2 vs. C4).

Claims

1. A method of making a rubber compound, the method comprising combining a conjugated diene polymer and a silica filler, wherein the silica filler has at least 80% SiO by weight based on the weight of the filler. 2 The invention relates to a conjugated diene polymer having a content of 1,2-dihydro-1,4-diene and ... 1 )(R' 2 )X n or a combination thereof, wherein X represents H or a cation, n is 1 or 0, and in the case where n is 1, the nitrogen atom N is positively charged, R represents a C1-C6 alkyl group, and R' 1 and R' 2 Independently represent H and C 1 -C 6 Alkyl, -Si(R' 4 )(R' 5 ) group, wherein R' 4 and R' 5 Independently represent C 1 -C 6 alkyl.

2. The method according to claim 1, in, The at least one polar group is selected from -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 in the case where n is 1, the nitrogen atom N is positively charged, R' 1 and R' 2 Independently represent H and C 1 -C 6 Alkyl, -Si(R' 4 )(R' 5 ) group, wherein R' 4 and R' 5 Independently represent C 1 -C 6 alkyl.

3. The method according to any one of the preceding claims, in, The functional group contains 1 to 20 Si atoms in addition to carbon and hydrogen atoms.

4. The method according to any one of the preceding claims, in, The functional group has 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 )-(II) Wherein in formula (I) and (II), R 1 , R 2 , R 3 , R 4 are the same or different and are selected from hydrogen or C optionally containing heteroatoms selected from O, N, S and Si 1 -C 12 alkyl, and where *- indicates a bond to the polymer chain, where R 1 and R 2 At least one of may also represent a polymer chain.

5. The method according to any one of the preceding claims, in, The functional groups are obtained by reaction with a functionalizing agent or a coupling agent or a combination thereof which produces at least a functional end group.

6. The method according to any one of the preceding claims, in, The functional group contains 1 to 12 silicon atoms and 1 to 30 carbon atoms.

7. The method according to any one of the preceding claims, in, The conjugated diene polymer is a copolymer comprising units 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, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-tert-butylstyrene, vinylnaphthalene.

8. The method according to any one of the preceding claims, in, The conjugated diene polymer comprises units derived from butadiene and styrene, and wherein the polymer is prepared by anionic solution polymerization.

9. The method according to any one of the preceding claims, in, The silica filler has an ion number IN 1 of less than 3, an ion number IN 2 of less than 20, or both, wherein IN 1 is calculated according to the following formula: IN1=[(Mg)+(K)] / [(Ca)+(Na)]×100, And where IN2 is calculated according to the following formula: IN2=[(Mg)+(Na)] / [(Ca)+(K)]×100, And in these two formulas, (Mg) is the magnesium ion concentration in the silica sample in mg / kg divided by the atomic weight of magnesium (24 g / mol); (K) is the potassium ion concentration in the silica sample in mg / kg divided by the atomic weight of potassium (39 g / mol); (Ca) is the calcium ion concentration in the silica sample in mg / kg divided by the atomic weight of calcium (40 g / mol); (Na) is the sodium ion concentration in the silica sample in mg / kg divided by the atomic weight of sodium (23 g / mol).

10. The method according to any one of the preceding claims, in, The silica filler has a potassium content greater than 100 mg / kg silica sample, a magnesium content greater than 100 mg / kg silica sample, or both.

11. The method according to any one of the preceding claims, in, The silica filler and the conjugated diene polymer are present in a weight ratio of 5:1 to 1:5, preferably 2:1 to 1:

2.

12. The method according to any one of the preceding claims, further comprising combining the polymer and the silica filler with at least one curing agent.

13. A rubber compound obtainable by the process according to any one of the preceding claims.

14. An article obtained by a process comprising curing the rubber compound according to claim 13 and wherein the process comprises at least one shaping step, wherein the shaping can be carried out before, during or after curing.

15. The article of claim 14 selected from a tire tread or a tire.

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