Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08C—TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS
  • C08C19/00—Chemical modification of rubber
  • C08C19/30—Addition of a reagent which reacts with a hetero atom or a group containing hetero atoms of the macromolecule
  • C08C19/42—Addition of a reagent which reacts with a hetero atom or a group containing hetero atoms of the macromolecule reacting with metals or metal-containing groups
  • C08C19/44—Addition of a reagent which reacts with a hetero atom or a group containing hetero atoms of the macromolecule reacting with metals or metal-containing groups of polymers containing metal atoms exclusively at one or both ends of the skeleton
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08C—TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS
  • C08C19/00—Chemical modification of rubber
  • C08C19/22—Incorporating nitrogen atoms into the molecule
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08C—TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS
  • C08C19/00—Chemical modification of rubber
  • C08C19/25—Incorporating silicon atoms into the molecule

Definitions

• This invention refers to a 1, 3 -butadiene and styrene copolymer product, functionalized at both extremities of its chains.
• This invention also refers to the preparation process of a 1, 3 -butadiene and styrene copolymer product, functionalized at both extremities of its polymeric chains.
• This invention further refers to compounds containing 1, 3 -butadiene and styrene copolymer product and use of the same .
• elastomers can be employed to obtain many important products when correctly used in the form of vulcanized compounds.
• the main products are tires in all their complexity, including their constituents such as tread, sidewalls etc, and mats, straps, and a wide range of technical products.
• tires manufactured with elastomers of the type SBR copolymers 1, 3 -butadiene-styrene
• SBR cold emulsion polymerization
• S-SBR solution polymerization
• bound styrene of approximately 23%wt
• the tires that are manufactured with conventional elastomers such as the 1,4-Cis BR (polybutadiene High Cis) , NR (Natural Rubber) and IR (Polyisoprene) , present low rolling resistance and low wet skid resistance (P. L.A. Coutinho, CH. Lira, L.
• Tg which provides an improvement in the skid resistance properties of the vulcanized compounds for tires (CH. Lira, L. F. Nicolini, G. Weinberg, N. M. T. Pires, P. L.A.
• Cis-BR and NR R. H. Schuster, H. M. Issel and V. Peterseim
• Elastomeric compounds used in the production of tires, especially in the tread, are normally composed of copolymers, formed by a conjugated diene and a monomer with an aromatic vinyl structure.
• Elastomers of type S-SBR are mainly used. These copolymers present a predominantly random distribution of their constituent mers along their polymeric chains and can also present sections with blocked distribution, or a mixture of random and blocked distribution. They are decisive in the obtainment of the final properties of the tire .
• patent EP 0929582 US
• Patent GB 2368069 describes the preparation process of the functionalized polymers in both extremities of the polymeric chains. Its structure is essentially that of a triblock, where the intermediary section can be a polydiene or a copolymer, resulting from the copolymerization between the conjugated diene and a monomer with an aromatic vinyl structure (e.g. : S-SBR) , where the end sections are preferentially polydialkylsiloxanes.
• S-SBR aromatic vinyl structure
• Patent EP 0849 333 B2 describes the use of substituted siloxanes in the preparation of the polydienes or copolymers, resulting from the copolymerization between the conjugated dienes and a monomer with an aromatic vinyl structure.
• the use of these functionalized polymers in vulcanized elastomeric compounds and their observed properties are also presented.
• Patent US 5,717,043 describes the preparation of polymers resulting from the copolymerization between conjugated dienes and a monomer with an aromatic vinyl structure (e.g.: S-SBR), functionalized with amine groups. These groups interact with the carbon black, utilized as a component of the vulcanized compounds, improving their properties.
• S-SBR aromatic vinyl structure
• said patent describes the use of a polymerization initiator prepared "in situ", in the obtainment of these polymers and the properties of the resulting vulcanized compounds.
• the patent also describes the use of coupling agents in the preparation of these polymers .
• Patent EP 0 992 536 Al describes the preparation of a polymer resulting from the anionic copolymerization between two conjugated dienes (e.g.: copolymer 1,3- butadiene- isoprene (S-IBR) .
• S-IBR copolymer 1,3- butadiene- isoprene
• This patent describes the use of polar compounds for the control of the microstructure of these copolymers, and the properties observed in vulcanized compounds .
• the abovementioned examples are perfectly- illustrative of the state of the art, in the sense that many of these developments are still considered current.
• there is an increase in demand for higher performance materials and products arising from, for example, the increase in the power of automobiles and improved highway conditions.
• the present invention concerns a product and a process of preparation of a new family of elastomers of type S-SBR, designed mainly for the production of high performance tires.
• the production of these elastomers uses advanced processes of polymerization, allowing larger control over the macrostructure and microstructure of the polymer.
• the control over the polymeric architecture allows the obtainment of elastomers with an improved balance of mechanical properties and better suitability to their end use.
• the objective of this invention is the preparation of elastomers of type S-SBR (copolymers of 1,3- butadiene-styrene) , modified in their structure and functionalized at the extremity of their polymeric chains, and their preparation process. More specifically, this invention deals with the preparation of copolymers of type S-SBR, with a controlled macrostructure and microstructure, the introduction of functional groups at the end of the polymeric chains, and the use of these copolymers in vulcanized elastomeric compounds and their properties .
• S-SBR copolymers of 1,3- butadiene-styrene
• polydienes and/or copolymers resulting from the copolymerization between conjugated dienes and a monomer with an aromatic vinyl structure, can be functionalized in their extremities, in the appropriate conditions, the effect of a structural change in the polymeric chains of these polymers, which includes the presence of terminal functional groups situated in both extremities of the polymeric chains, one of them preferentially being of the siloxane type, in the properties of the vulcanized elastomeric compounds, is not known in the state of the art .
• the elastomers in this invention are copolymers of the type functionalized S-SBR, produced by the process of anionic polymerization in solution.
• They are basically formed by a preferential composition between one or more conjugated dienes and one or more monomers with an aromatic vinyl structure, in appropriate proportions. They have a controlled macrostructure and microstructure, with an appropriate content of 1,2-vinylic units, based on the conjugated diene incorporated in the copolymer, and the specific functional groups in the polymeric structure.
• elastomers have a predominantly random distribution of their constituent mers, along the polymeric chains. At the end of these chains, in both extremities, there are specific functional groups that interact and/or react with the reinforcement fillers utilized in the vulcanized elastomeric compounds. Furthermore, their chains present linear structures or a composition of linear, branched and/or radial structures, with a controlled microstructure, and have a determinate content of 1,2-vinylic units, based on the conjugated diene incorporated in the copolymer. Elastomers containing linear, branched and radial polymeric chains are obtained, in the appropriate conditions.
• these elastomers are copolymers obtained by the polymerization of one or more monomers of the conjugated diene type (e.g.: 1, 3 -butadiene) with one or more monomers with an aromatic vinyl structure (e.g.: styrene) , which present a predominantly random distribution of constituent mers in their polymeric chains, so that the microsequences of one of these mers are preferentially less than 10 units, mainly for the aromatic vinyl mers.
• their polymeric chains have a linear, branched or radial structure.
• the polymeric chains are functionalized at both the extremities with specific functional groups, which interact and/or react with the reinforcement fillers of the vulcanized elastomeric compounds.
• One of the extremities of the polymeric chains is functionalized preferentially with silyl, silanol and siloxane type groups, represented by the structures: -SiH 2 (OH), -Si(Ri) 2 (OH), -SiH(OH) 2 , -SiRi(OH) 2 , -Si(OH) 3 , -Si(ORi) 3 , -(SiRiR 2 O) x -R 3 , -Si (R 3 ) 3 - m (X) m , where X is a halogen, x is the number of repetitive units between 1 and 500, m is the number of linked groups, varying from 0 to 3, Ri and R 2 are identical or different, and can be alkoxy or alkyl, linear or branched, cycloalkyl, aryl, alkylaryl, aralkyl or vinyl groups, in each case having 1 to 20 carbon atoms, and R 3 is H or alkyl
• the other extremity of the polymeric chains of these elastomers is preferentially functionalized with groups of the type -OH, -COOH, -COX, where X as a halogen, -SH, -CSSH, -NCO, amine or epoxy.
• the amine groups can be represented by the following structures: -N(Ri) 2 , -NRiR 2 - NHR 1 , -NH 2 , where Ri and R 2 are identical or different, can be alkyl, linear or branched, cycloalkyl, aryl, alkylaryl, aralkyl or vinyl groups, in each case having 1 to 20 carbon atoms .
• amine type represented by the structures -N(Ri) 2 , -NR x R 2 , - NHRi, -NH 2 , where R 1 and R 2 are identical or different, can be alkyl, linear or branched, cycloalkyl, aryl, alkylaryl, aralkyl or vinyl groups, in each case having 1 to 20 carbon atoms, and at the other extremity of the polymeric chains, functional groups preferentially of the siloxane type, in the form of structures that can be represented by the general formula -- [--Si (RiR 2 ) -0-] n --Si (RiR 2 ) -OH, where Ri and R 2 are identical or different, and can be alkoxy or alkyl, linear or branched, cycloalkyl, aryl, alkylaryl, aralkyl or vinyl groups
• Small sections or microsequences of one of the monomers of the copolymer, situated along the polymeric chains, can also form part of the structure of these elastomers .
• the elastomers of this invention present a percentage composition in weight of their chains, which can vary from 5% to 50%, , for the aromatic vinyl monomer (e.g.: styrene) , and from 50% to 95% for the conjugated diene (e.g.: 1, 3 -butadiene) .
• these elastomers present a composition from 15% to 40%, for the percentage in weight of the monomer with an aromatic vinyl structure, and from 60% to 85% for the percentage in weight of the conjugated diene incorporated in the copolymer.
• Both extremities of their polymeric chains are functionalized, one of them preferentially with amine groups, and the other with siloxane groups, followed by silanol groups .
• an amine is used, preferentially pyrrolidine.
• a siloxane is used, preferentially hexamethylcyclotrisiloxane (D 3 ) , which allows the incorporation of continuous sequences of the siloxane functional group -- [--Si (CH 3 ) 2 -0-] --, and a silanol terminal group --Si(CH 3 J 2 -OH.
• Mll+4 @ 100 0 C Mooney Viscosity
• These elastomers present glass transition temperatures, Tg, in the range from -92°C to -I 0 C 1 depending on the content of the aromatic vinyl monomer of the copolymer and the microstructure of the conjugated diene incorporated in the copolymer.
• the elastomers of this invention are functionalized in both extremities of their polymeric chains, in one with amine groups, preferentially pyrrolidine, and in the other extremity with siloxane groups, preferentially with hexamethylcyclotrisiloxane (D 3 ) , which allows the incorporation of a sequence of siloxane groups - [--Si (CH 3 ) 2 -0--] -, which vary in the range from 1 to 500 units per polymeric chain, followed by the silanol termination (--Si(CH 3 J 2 -OH) .
• A represents the polymeric chains of a polymer, formed by the copolymerization between one or more conjugated dienes with one or more monomers with an aromatic vinyl structure (e.g.: S-SBR), which have a preferentially random distribution of their constituent mers, linear structure (group 1) , or a preferential composition of linear, branched and/or radial structures (group 2) , as well as a controlled content of 1,2-vinylic units, based on the incorporated conjugated diene;
• Fi represents a terminal functionalization of the polymeric chains, and can be groups of the type -OH, -COOH, -COX, where X is a halogen, -SH, -CSSH, -NCO, amine, and epoxy, the amine groups may be represented by the following structures -N(Rx) 2 , -NRiR 2 , -NHRi, -NH 2 , where R 1 and R 2 are identical or different, can be alkyl, linear or branched,
• F 2 represents one of the extremities of the polymeric chains, functionalized preferentially with silyl, silanol and siloxane type groups, represented by the structures: -SiH 2 (OH), -Si(Ri) 2 (OH), -SiH(OH) 2 , -SiR x (OH) 2 , -Si(OH) 3 , -Si(OR 1 J 3 , -(SiRiR 2 O) x -R 3 , -Si (R 3 ) 3 -m(X)m, where X is a halogen, x is the number of repetitive units between 1 and 500, m is the number of linked groups, varying from 0 to 3 , Ri and R 2 are identical or different, and can be alkoxy or alkyl, linear or branched, cycloalkyl, aryl, alkylaryl, aralkyl or vinyl groups, in each case having 1 to 20 carbon atoms, and R 3 is H or
• A represents the polymeric chains of a polymer formed by the copolymerization of the monomers 1,3- butadiene and styrene, with a random distribution of their constituent mers, and a determinate content of the 1,2- vinylic structures, based on the content of the diene incorporated in the copolymer;
• Fi represents terminal amine groups, preferentially pyrrolidine;
• C represents the coupling agent employed in the preparation of elastomers, which has a functionality larger or equal to 2, being preferentially silicon tetrachloride (SiCl 4 ) or tin tetrachloride (SnCl 4 ) ;
• F 2 represents siloxane groups, preferentially hexamethylcyclotrisiloxane (D 3 ) , which allows the incorporation of a sequence of siloxane groups -[-- Si (CH 3 ) 2-0--] -, which vary in the range from 1 to 500
• the anionic polymerization allows the obtainment of polymers with a controlled architecture . Due to their large versatility, varied polymeric structures can be obtained, allowing a large control over the microstructure and the macrostructure of the polymer, including the incorporation of functional groups in the polymeric chains . The use of this process requires a rigorous inspection of the employed materials to remove any impurities that could act as terminators and/or damage the control of the polymerization.
• the elastomers cited in this invention are obtained by this process of polymerization, with the use of different reaction conditions and additives that aim to incorporate determinate characteristics in the final product .
• the process of polymerization of these elastomers can be conducted in a continuous manner or in batches .
• the batch process is normally preferred since it provides a better control over the variables that affect the molecular architecture of the polymer.
• the reactions of the polymerization are realized employing solvents, preferentially apolar, such as cyclohexane or n-hexane, although other solvents of the aliphatic class can also be utilized.
• Solvents of the aromatic class such as toluene, can also be employed.
• the initiator normally employed in these polymerizations is n-butyl-lithium although, in general, compounds of the group of alkyl-lithiums can also be employed.
• alkyl groups of these initiators are: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec- butyl, t-butyl, n-amyl, sec-amyl, n-hexyl, sec-hexyl, n- heptyl, n-octyl, n-nonyl, n-dodecyl and octadecyl .
• the initiators are: n-butyl- lithium, sec-butyl-lithium, n-propyl-lithium, isobutyl- lithium, t-butyl-lithium and amyl-lithium.
• the monomers 1, 3 -butadiene and styrene are mainly used for the production of these elastomers, although other conjugated dienes and other vinyl-aromatic monomers can also be employed.
• conjugated dienes aside from 1,3- butadiene, there are: 2-alkyl-1, 3 -butadiene, 2,3-dialkyl- 1, 3 -butadiene, 2 -alkyl-3 -alkyl-1, 3 -butadiene, 1,3- pentadiene, 1, 3-hexadiene, 2,4-hexadiene, etc.
• vinyl-aromatic monomers can also be employed, such as alpha-methyl-styrene, orto, meta and para divinylbenzene, orto, meta and para- methylstyrene, para-t-butyl-styrene, vinyl-toluene, methoxystyrene, vinylmesitylene, etc.
• polar substances that act as Lewis bases, such as N, N, N" , lST-tetramethylethylenediamine (TMEDA) , tetrahydrofurane (THF) or ditetrahydrofurylpropane (DTHFP) .
• TEDA lST-tetramethylethylenediamine
• THF tetrahydrofurane
• DTHFP ditetrahydrofurylpropane
• ethers and amines can also be utilized, for example: dimethyl ether, diethyl ether, di-n-propyl ether, diisopropyl ether, di-n-butyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, trimethyl amine, triethyl amine, N-methyl morpholine, N-ethyl morpholine, N- phenyl morpholine, etc.
• terminal functionalization of these elastomers is introduced with the objective of improving the interaction of the polymeric chains with the reinforcement fillers in the vulcanized compounds. It is usually introduced utilizing a functionalized initiator, a functionalized terminator, or by the reaction between the active anionic terminals of the polymeric chains and the compounds that contain desirable functional groups.
• a large variety of functionalizations can, in principle, be incorporated in these elastomers. It is preferable that these functionalizations be incorporated in the extremities of the polymeric chains.
• a functional group can be introduced via the utilization of a functionalized initiator, and the other by the utilization of a terminator, also functionalized, at the end of the polymeric chains.
• one of the functional groups of the polymeric chains should be preferentially of the siloxane type.
• Patents EP 396780 and EP 849333 provide examples of compounds and processes that can be employed with this purpose .
• terminal functional groups of the polymeric chains of the elastomers of this invention are preferentially of type -OH, -COOH, -COX, where X is a halogen, -SH, -CSSH, -NCO, amine, epoxy, silyl, silanol or siloxane, as well as the polysiloxane and siloxane groups or polysiloxane containing amine groups.
• X is a halogen, -SH, -CSSH, -NCO, amine, epoxy, silyl, silanol or siloxane, as well as the polysiloxane and siloxane groups or polysiloxane containing amine groups.
• Amine groups -N(Ri) 2 , -NR 2 R 2 , -NHRi, -NH 2 , where Ri and R 2 are identical or different, can be alkyl groups, linear or branched, cycloalkyl, aryl, alkylaryl, aralkyl or vinyl, in each case having from 1 to 20 carbon atoms ;
• Silyl, silanol and siloxane groups SiH 2 (OH), -Si(R 1 J 2 (OH), -SiH(OH) 2 , -SiR 1 (OH) 2 , -Si(OH) 3 ,-- Si(ORi) 3 , -(SiRiR 2 O) x -R 3 , -Si (R 3 ) 3 - m (X) m , where X is a halogen, x is the number of repetitive units between 1 to 500, m is the number of replacement groups, and can vary from 0 to 3, Ri and R 2 are identical or different, and can be alkoxy or alkyl groups, linear or branched, cycloalkyl, aryl, alkylaryl, aralkyl or vinyl, in each case having from 1 to 20 carbon atoms, and R 3 is H or alkyl, branched or linear, in each case having from 1 to 20 carbon atoms, or a monon
• Siloxane groups that contain amine groups represented by the formula -A ⁇ Si (A 2 -N( (H) k [R 1 ) 2 - k ) ) y (0Ri) z (R 3 ) 3 -( y+z ) , where: k can vary from 0 to 2 , y can vary from 1 to 3 , and z can vary from 0 to 2 , 0 ⁇ y+z ⁇ 3, R 1 and R 2 are identical or different, and can be alkyl groups, linear or branched, cycloalkyl, aryl, alkylaryl, aralkyl or vinyl, in each case having from 1 to 20 carbon atoms, , aryl mononuclear groups, R 3 is H or alkyl, branched or linear, in each case having from 1 to 20 carbon atoms, or a mononuclear aryl group, and A 1 and A 2 are chains of up to 12 carbon atoms, linear or branched
• the elastomers of this invention are functionalized at the extremities of their polymeric chains, in one with amine groups, preferentially pyrrolidine, and in the other extremity with siloxane groups, preferentially with hexamethylcyclotrisiloxane
• This invention uses a method of polymerization divided into sequential steps, which allows a large control over the polymeric architecture.
• 1 st step formation of the amine-functionalized initiator and copolymerization of the 1, 3-butadiene- styrene .
• the random copolymerization is performed, in an appropriate reactor, involving the selected monomers.
• a monomer with an aromatic vinyl structure e.g.: styrene
• a conjugated diene e.g.: 1, 3 -butadiene
• the percentage ratio in weight between these monomers varies in the range from 5% to 50% for the aromatic vinyl monomer and from 50% to 95% for the conjugated diene. More specifically, it adopts a content in the range from .15% to 40% in weight for the aromatic vinyl monomer, and in the range from 60% to 85% in weight for the conjugated diene, for these copolymers.
• the copolymerization reaction is conducted in an appropriate apolar solvent, normally using cyclohexane or n-hexane.
• the percentage ratio in weight monomers / solvent is controlled to ensure that the content of the total solids at the end of the reaction are found in the range from 8% to 30%. More specifically, it is employed in the range of total solids from 10% to 18%, and even more specifically, it is desirable that the content of the solids of these reactions is from 12% to 16%.
• organometallic compounds of lithium are employed for the initiation of these reactions.
• N-butyl- lithium is preferred as the initiator, due to its appropriate reactivity with the copolymerization 1,3- butadiene-styrene and its larger commercial availability.
• the quantity employed of this initiator is related to the total mass of the monomers employed in the reaction and the end molecular weight desired for the copolymer .
• pyrrolidine is used in the first step of the reaction.
• a polar additive is also used at this step of the copolymerization, which acts as a Lewis base, which is added to the reaction medium, before the start of the reaction. Its function is to increase the content of the 1,2-vinylic units of the polymeric chains.
• copolymers present a content of 1,2-vinylic units in the range from 8% to 80%, considering the total of the diene incorporated with the copolymer. It is desirable that the content of the 1,2- vinylic units be in the range from 10% to 70%. More specifically, a content of 1,2-vinylic units between 55 and 65% is preferred.
• This additive is not consumed during the copolymerization and the quantity utilized depends on an appropriate molar relation with the quantity of initiator employed. This relation is chosen to allow a better control of the kinetics of the reaction, as well as the microstructure of the diene incorporated with the copolymer .
• the reaction of the copolymerization strictly speaking, is achieved in the range of temperature between 25°C and 120 0 C. More specifically, the copolymerization is achieved between 30 0 C and 90 0 C. Even more specifically, the copolymerization is achieved between 30 0 C and 80 0 C, which is maintained until the total conversion of the monomers, which normally occurs between 30 and 55 minutes.
• the control of the temperature during this step is fundamental for the obtainment of the desired content of the 1,2- vinylic units, which vary depending on the temperature of the reaction.
• the pressure of the reactor during this step varies normally in the range from 3 Kgf/crn 2 to 5 Kgf/cm 2 .
• Route 1 elastomer containing only linear polymeric chains .
• the compound in the second step the compound is added that will functionalize the copolymer with the still active anionic chains, in the range of temperature between 60 0 C and 80 0 C, and the same range of pressure employed in the previous step.
• hexamethylcyclotrisiloxane (D 3 ) is employed as the functionalizing agent.
• This cyclic compound allows, by the opening of its ring, the incorporation of the continuous sequences of the siloxane functional group (-- [--Si (CH 3 ) 2 -O-] --) .Once this step is concluded, which normally takes from 15 to 20 minutes, a terminator agent is added, maintaining the same previous reactionary conditions. Cetylic alcohol, or other alcohol with a high molecular weight, is employed as the terminator agent of the polymerization.
• This final step is normally concluded in 10 minutes, with the deactivation of all the active anionic chains and the formation of the silanol terminal group - Si (CH 3 ) 2 -OH in the polymeric chains.
• the elastomer thus obtained has linear polymeric chains, which are functionalized with amine groups, in one of the extremities, and with siloxane groups, followed by silanol termination, in the other extremity.
• the elastomer is subsequently stabilized with the addition of an appropriate quantity of trynonylphenylphosphite and octadecyl 3, 5-di-t-butyl-4- hydroxyhydrocinnamate antioxidants .
• Route 2 elastomer containing a preferential composition of linear, branched and/or radial polymeric chains .
• a coupling agent is added, with a functionality larger or equal to 2, which reacts with the active anionic chains, generating radial polymeric structures.
• This reaction is realized in the range of temperature between 55 0 C and 95 0 C, preferentially in the range of temperature between 65 0 C and 75 0 C, and the same range of pressure employed in the previous step.
• the control of the efficiency of this coupling reaction is essential for the obtainment of an elastomer with an appropriate composition of linear and radial chains.
• the efficiency of this reaction is normally found in the range from 5% to 95%, preferentially in the range from 20% to 60%.
• silicon tetrachloride SiCl 4 is used preferentially as the coupling agent, which allows the coupling or union of up to four active chains per molecule.
• the partial coupling of the polymeric chains with SiCl 4 performed in this step, allows for a fraction of the original polymeric chains to remain active, making their functionalization possible.
• the compound is added that will functionalize the remaining active chains, in the range of temperature between 60 °C and 80 0 C, and the same range of pressure employed in the previous step.
• hexamethylcyclotrisiloxane (D 3 ) is employed as the functionalizing agent.
• This cyclic compound allows, by the opening of its ring, the incorporation of the continuous sequences of the siloxane functional group (-- [--Si (CH 3 ) 2 -O-] --) .
• a terminator agent is added, maintaining the same previous reactionary conditions. Cetylic alcohol, or other alcohol with a high molecular weight, is employed as the terminator agent of the polymerization .
• This final step is normally concluded in 10 minutes, with the deactivation of all the remaining active anionic chains and the formation of the silanol terminal group -Si(CH 3 J 2 -OH in the remaining active anionic chains.
• the elastomer thus obtained has a preferential composition of linear and radial polymeric chains functionalized in their extremities.
• the linear chains are functionalized with amine groups, in one of the extremities, and with siloxane groups, followed by silanol termination, in the other extremity.
• the chains with a radial structure are only functionalized with amine groups in their extremities.
• the elastomer is subsequently stabilized with the addition of an appropriate quantity of trynonylphenylphosphite and octadecyl 3, 5-di-t-butyl-4- hydroxyhydrocinnamate antioxidants .
• the first step was performed of the anionic copolymerization of the 1, 3 -butadiene monomers and styrene, in a solution of cyclohexane, with the polar additive TMEDA, and using n-butyl-lithium as the initiator.
• the reactor was filled with 61.3 Kg of 1, 3 -butadiene, 15.5 Kg of styrene, 470.6 Kg of cyclohexane and 0.2 Kg of TMEDA, 0.030 Kg of pyrrolidine, aiming for a content of total solids at the end of the reaction of 14% in weight.
• n-butyl-lithium reacts preferentially with the pyrrolidine, generating a functionalized initiator with this amine.
• This new initiator, generated "in situ”, is what properly initiates the copolymerization, functionalizing with an amine group at one of the extremities of the polymeric chains.
• the copolymerization was conducted semi- adiabatically, with the temperature between 32 0 C and 76 0 C, until the total conversion of the monomers, which normally occurs in 55 minutes.
• This step was conducted with the temperature between 65°C and 75°C, for a period of 15 to 20 minutes.
• the elastomer produced was recovered by the drying by evaporation of the solvent of the polymeric solution, in an open mill, heated to 100 0 C.
• the Mooney viscosity (Mll+4 @ 100 0 C) of the produced elastomer was 57.
• the total content of styrene in the copolymer was 20.9% and the content of the 1,2-vinylic units, based on the incorporated 1, 3 -butadiene, was 63.9%. Both these results were obtained using RMN 1 H spectroscopy.
• the confirmation of the functionalization with siloxane groups in the elastomer was obtained via RMN 1 H spectroscopy, analyzing a sample of the elastomer submitted to a process of purification, in which a cycle of dissolution in cyclohexane followed by coagulation in ethanol and drying, was repeated 3 times, to remove any residual of the functionalizing agent not incorporated in the polymeric chains.
• the analysis was performed with the sample dissolved in CDCl 3 (deuterated chloroform) , without the use of TMS (tetramethylsilane) as a marker.
• UV-VIS spectroscopy was used, analyzing a sample of the previously purified elastomer.
• the method is based on the interaction/reaction between the amine groups of the elastomer and the reagent "Patent Blue", forming an ammonium salt that can be observed in a wavelength of 628 nm.
• This method requires the prior preparation of a calibration curve, which was obtained by the preparation of standards and of the respective UV-VIS spectroscopic analyses .
• an elastomer of type S-SBR containing a composition of linear, branched and/or radial polymeric chains, which have a random distribution of their constituent mers, functionalized in both their extremities, one with an amine group and the other with a siloxane group (--[-Si(CH 3 J 2 -O-]--), followed by a silanol termination (-- Si(CH 3 J 2 -OH), and a controlled microstructure.
• the first step was performed of the anionic copolymerization of the 1, 3 -butadiene monomers and styrene, in a solution of cyclohexane, with the polar additive TMEDA, and using n-butyl-lithium as the initiator.
• the reactor was filled with 61.3 Kg of 1, 3 -butadiene, 15.5 Kg of styrene, 471 Kg of cyclohexane and 0.35 Kg of TMEDA and 0.050 Kg of pyrrolidine
• n-butyl-lithium reacts preferentially with the pyrrolidine, generating a functionalized initiator with this amine.
• This new initiator, generated "in situ”, is what effectively initiates the copolymerization, functionalizing with an amine group at one of the extremities of the polymeric chains.
• the copolymerization was conducted semi- adiabatically, with the temperature between 30°C and 72 0 C, until the total conversion of the monomers, which normally occurs in 55 minutes.
• the pressure of the reactor varied in the range from 3 Kgf/cm 2 to 5 Kgf/cm 2 in this step.
• a second step 0.0087 Kg of silicon tetrachloride was added, for the coupling of 30% of the active polymeric chains. This step was conducted with the temperature between 65 0 C and 75 0 C for a period of 5 minutes, in the same range of pressure as the previous step.
• the elastomer obtained in this way with linear and radial polymeric chains, functionalized with an amine group and siloxane groups followed by silanol, was subsequently stabilized with the addition of 0.30 Kg of the antioxidant trynonylphenylphosphite and 0.15 Kg of the antioxidant octadecyl 3, 5-di-t-butyl-4- hydroxyhydrocinnamate .
• the elastomer produced in this way was recovered by the drying by evaporation of the solvent of the polymeric solution, in an open mill, heated to 100 0 C.
• the Mooney viscosity (Mll+4 @ 100 0 C) of the produced elastomer was 59.7.
• the total content of styrene in the copolymer was 21.4% and the content of the 1,2- vinylic units, based on the incorporated 1, 3 -butadiene, was 64.2%. Both these results were obtained using RMN 1 H spectroscopy.
• the molecular weight and the polydispersion of the elastomer were determined by Size Exclusion
• DSC Differential Scanning Calorimetry .
• SEC Size Exclusion Chromatography
• PS polystyrene
• SBR 1 is a solution polymerized SBR comprising uncoupled polymer molecules which are substituted with amino groups at one polymer chain end and coupled polymer molecules which carry amino groups at each chain end.
• Vinyl content 66 weight-% Styrene content : 20 weight-% Mooney-viscosity (ML1+4 ) : 40
• SBR 2 is a solution polymerized SBR comprising uncoupled polymer molecules which are substituted with amino groups at one polymer chain end and coupled polymer molecules which carry amino groups at each chain end.
• Vinyl content 66 weight-% Styrene content : 20 weight-% Mooney-viscosity (ML1+4 ) : 40
• SBR 2 is a solution polymerized SBR comprising uncoupled polymer molecules which are substituted with amino groups at one polymer chain end and coupled polymer molecules which carry amino groups at each chain end.
• Vinyl content 66 weight-% Styrene content : 20 weight-% Mooney-viscosity (ML1+4 )
• SBR 2 is a SBR according to the invention which consists of uncoupled polymer molecules which carry amino groups at one polymer chain end as well as Si-OH groups at the other chain end and coupled polymer molecules which carry amino groups at each chain end.
• Vinyl content 66 weight-%
• Styrene content 20 weight-%
• the compounds were vulcanized for 20 minutes at 160 0 C after the mixing procedure.
• the physical properties of the vulcanizates are listed in Table 5.
• a low rolling resistance is advantageous for tires.
• a low rolling resistance can be expected from measurements done at the vulcanizate when the rebound at 60 0 C is high and the tan ⁇ value at 60 0 C (from dynamic damping experiment) as well as the tan ⁇ maximum (from the amplitude sweep measurement) are low.
• Table 5 that the vulcanizate from example V2 has a high rebound at 60 0 C as well as a low tan ⁇ value at 60 0 C (from dynamic damping experiment) and a low tan ⁇ maximum (from the amplitude sweep measurement) .

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• 2007
  • 2007-12-14 BR BRPI0705025 patent/BRPI0705025A2/pt not_active Application Discontinuation
• 2008
  • 2008-12-11 WO PCT/IB2008/003437 patent/WO2009077837A1/en active Application Filing

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