Complexed polymer and method for producing the same, and rubber composition and method for producing the same

Abstract

To provide a polymer having improved tensile strength at break (TB) and elongation at break (EB).SOLUTION: There is provided a complexed polymer which contains a polymer chain containing a diene unit and / or an olefin unit and two or more functional groups containing oxygen atoms bonded to the main chain and / or side chains of the polymer chain, wherein in at least two of the functional groups, an oxygen atom in the functional groups is bonded to adjacent carbon atoms of the main chain and / or side chains of the polymer chain and is complexed with a metal ion of an element in groups 3 to 12 of the periodic table.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a complexed polymer, a method for producing the same, a rubber composition, and a method for producing the same.

Background Art

[0002] Conventionally, most vulcanized rubber products such as used tires have been discarded without being reused. In recent years, however, recycling of used vulcanized rubber products has become an urgent issue from the viewpoints of environmental problems and resource saving. As a method for recycling used vulcanized rubber products, for example, a method is known in which recycling is performed by applying heat and shearing force to used vulcanized rubber products using a twin-screw extruder. However, crosslinked polymers such as those in vulcanized rubber products are regenerated through treatment under severe conditions, which inevitably causes degradation. For example, rubber products using recycled rubber have inferior physical properties such as tensile strength at break (TB) and elongation at break (EB) compared to rubber products not using recycled rubber.

[0003] On the other hand, Patent Document 1 below discloses an elastomer containing vicinal diol units having a specific structure and but-1-ene-1,4-diyl units having a specific structure, and teaches that the elastomer is excellent in toughness and has recyclability.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] However, the present inventors have found that the elastomer described in Patent Document 1 is an elastomer crosslinked by hydrogen bonding of diols, and that these hydrogen bonds are easily dissociated at high temperatures, making it impossible to maintain physical properties such as tensile strength at break (TB) and elongation at break (EB).

[0006] Therefore, the object of the present invention is to solve the problems of the above-mentioned prior art and to provide a polymer (such as rubber) and a method for producing the same that have improved tensile strength (TB) and elongation (EB) at break. Furthermore, a further objective of the present invention is to provide a rubber composition containing such polymer and having improved tensile strength at break (TB) and elongation at break (EB), as well as a method for producing the same. [Means for solving the problem]

[0007] The gist of the present invention, which solves the above problems, is as follows.

[0008] The complexed polymer of the present invention comprises a polymer chain containing diene units and / or olefin units, and two or more functional groups containing oxygen atoms bonded to the main chain and / or side chains of the polymer chain. At least two of the functional groups are characterized in that the oxygen atoms in the functional groups are bonded to adjacent carbon atoms in the main chain and / or side chains of the polymer chain, and are complexed with metal ions of elements from groups 3 to 12 of the periodic table. The complexed polymer of the present invention exhibits improved tensile strength at break (TB) and elongation at break (EB).

[0009] In a preferred example of the complexed polymer of the present invention, the bond dissociation energy between the metal ion and the functional group is 100 kJ / mol or more. In this case, the tensile strength (TB) and elongation (EB) at cleavage of the complexed polymer are further improved.

[0010] In another preferred example of the complexed polymer of the present invention, the metal ion and the functional group are bonded by a coordination bond. In this case, sufficient reversibility can be imparted to the bond between the metal ion and the functional group.

[0011] In the complexed polymer of the present invention, it is preferable that at least two of the functional groups have oxygen atoms bonded to the metal ions. In this case, the tensile strength (TB) and elongation (EB) at cleavage of the complexed polymer are further improved.

[0012] In the complexed polymer of the present invention, it is preferable that at least two of the functional groups containing oxygen atoms are derived from hydroxyl groups. In this case, the tensile strength (TB) and elongation (EB) at cleavage of the complexed polymer are further improved.

[0013] In other preferred examples of the complexed polymer of the present invention, the metal ions are selected from metal ions of elements in the fourth and fifth periods of the periodic table. In this case, the tensile strength (TB) and elongation (EB) at cleavage of the complexed polymer are further improved.

[0014] In another preferred example of the complexed polymer of the present invention, the metal ions are selected from metal ions of elements in groups 7 to 12 of the periodic table. In this case, a higher strength crosslinking can be formed.

[0015] Here, it is preferable that the metal ion is at least one selected from the group consisting of iron ions, copper ions, and zinc ions. In this case, a cross-linked structure with higher strength can be formed.

[0016] In another preferred example of the complexed polymer of the present invention, the functional group is bonded in an amount of 0.1 to 40 mol% relative to the monomer units in the polymer chain. In this case, the tensile strength (TB) and elongation (EB) at cleavage of the complexed polymer are further improved, and a complexed polymer with sufficient elastomeric properties is easily obtained.

[0017] In the complexed polymer of the present invention, it is preferable that the metal ions are complexed by adding a metal salt to the polymer chain to which the functional groups are bonded. In this case, a complexed polymer can be easily obtained, and a crosslink with high strength can be formed.

[0018] Here, the metal salt is preferably a metal halide. Metal halides are easy to handle and can more conveniently form high-strength crosslinks.

[0019] Further, the metal salt is more preferably a metal chloride. Metal chlorides are easy to handle and can more conveniently form high-strength crosslinks.

[0020] Further, the metal salt is preferably other than metal oxides, metal carbonates, and metal fatty acid salts. In this case, it becomes easier to form crosslinks via coordinate bonds.

[0021] Further, the rubber composition of the present invention is characterized by comprising the above complexed polymer. The rubber composition of the present invention has improved tensile strength at break (TB) and elongation at break (EB).

[0022] Further, the method for producing a complexed polymer of the present invention is the above method for producing a complexed polymer, wherein the method comprises reacting a polymer chain having the functional group bonded thereto with a metal salt containing an element belonging to Groups 3 to 12 of the periodic table. According to the method for producing a complexed polymer of the present invention, the complexed polymer can be easily obtained.

[0023] In a preferred embodiment of the method for producing a complexed polymer of the present invention, the molar ratio of the functional group bonded to the polymer chain to the metal salt (functional group bonded to the polymer chain / metal salt) is 4 or more. In this case, excess metal ions derived from the metal salt can be reduced, and deterioration of the complexed polymer caused by metal ions can be suppressed.

[0024] Further, the method for producing a rubber composition of the present invention is the above method for producing a rubber composition, wherein a polymer chain having the functional group bonded thereto is mixed with a metal salt containing an element belonging to Groups 3 to 12 of the periodic table training to produce a complexed polymer. The present invention's method for producing a rubber composition offers excellent productivity because it allows for the preparation of the complexing polymer during the production of the rubber composition (kneading of the rubber composition).

[0025] In a preferred example of the method for producing the rubber composition of the present invention, the amount of the metal salt blended is 0.1 to 10 parts by mass per 100 parts by mass of the polymer chain to which the functional group is bonded. In this case, the tensile strength (TB) and elongation (EB) at break of the rubber composition are further improved, and the excess metal ions derived from the metal salt can be reduced, thereby suppressing the degradation of the complexed polymer caused by the metal ions. [Effects of the Invention]

[0026] According to the present invention, it is possible to provide a polymer with improved tensile strength at break (TB) and elongation at break (EB), as well as a method for producing the same. Furthermore, according to the present invention, it is possible to provide a rubber composition containing such polymer, which has improved tensile strength at break (TB) and elongation at break (EB), as well as a method for producing the same. [Modes for carrying out the invention]

[0027] The complexed polymer and its manufacturing method, as well as the rubber composition and its manufacturing method, of the present invention will be described in detail below, based on embodiments.

[0028] <Complexed polymer> The complexed polymer of the present invention comprises a polymer chain containing diene units and / or olefin units, and two or more functional groups containing oxygen atoms bonded to the main chain and / or side chains of the polymer chain. At least two of the functional groups are characterized in that the oxygen atoms in the functional groups are bonded to adjacent carbon atoms in the main chain and / or side chains of the polymer chain, and are complexed with metal ions of elements from groups 3 to 12 of the periodic table.

[0029] The complexed polymer of the present invention comprises a polymer chain and two or more functional groups containing oxygen atoms, wherein at least two of the functional groups are complexed with metal ions of elements from groups 3 to 12 of the periodic table. Here, at least two of the functional groups have oxygen atoms bonded to adjacent carbon atoms in the main chain and / or side chains of the polymer chain; that is, in the complexed polymer of the present invention, at least two functional groups are located in close proximity. Therefore, by complexing these at least two functional groups with metal ions of elements from groups 3 to 12 of the periodic table, the polymer chain can be crosslinked with a strength higher than that of hydrogen bonding, thereby improving the tensile strength at break (TB) and elongation at break (EB). Therefore, the complexed polymer of the present invention has high tensile strength (TB) and elongation (EB) at break.

[0030] Furthermore, since the bond between the metal ion and the functional group is not a sulfur-based bond like that of typical vulcanized rubber, the bond can be easily broken, and for example, it can be fluidized by heating and remolded. Because the bond can be easily broken in this way, there is no need to expose the complexed polymer to harsh conditions in order to break the bond. Moreover, since the polymer chain having a functional group containing an oxygen atom, which is generated by breaking the bond between the metal ion and the functional group, does not need to be exposed to harsh conditions in order to break the bond, the performance of the polymer chain is maintained, and even if the complexed polymer is regenerated by complexing the polymer chain having the functional group with a metal ion, it can maintain the same performance as when it was new. Therefore, the complexed polymer of the present invention is also recyclable.

[0031] (polymer chain) The complexed polymer of the present invention comprises polymer chains containing diene units and / or olefin units. That is, the polymer chains contain either diene units or olefin units, or both diene units and olefin units. Here, there is one or more polymer chains. When there is one polymer chain, the complexed polymer forms a crosslinked structure intramolecularly via metal ions. When there are two or more polymer chains, crosslinked structures can be formed not only intramolecularly but also intermolecularly (between polymer chains) via metal ions. The complexed polymer has two or more functional groups in order to form a crosslinked structure, and these two or more functional groups may be the same or different.

[0032] The aforementioned diene units may be conjugated diene units (conjugated diene units) or unconjugated diene units (non-conjugated diene units).

[0033] The aforementioned conjugated diene unit is a monomer unit derived from a conjugated diene compound. The conjugated diene compound used as a monomer preferably has 4 to 8 carbon atoms. Specific examples of such conjugated diene compounds include 1,3-butadiene, isoprene, 1,3-pentadiene, and 2,3-dimethyl-1,3-butadiene. Furthermore, from the viewpoint of good elastomeric properties, the conjugated diene compound used as a monomer preferably contains 1,3-butadiene and / or isoprene.

[0034] The aforementioned non-conjugated diene unit is a monomer unit derived from a non-conjugated diene compound. Examples of non-conjugated diene compounds as monomers include those with the following general formula (1): [ka] [In the formula, R 1 Each of these is independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms. Examples include cycloocta-1,5-diene compounds represented by [ ]. As the cycloocta-1,5-diene compound of general formula (1), a commercially available compound may be used, or one synthesized according to a known method may be used. From the viewpoint of availability, etc., R 1 However, compounds comprising a hydrogen atom, a halogen atom, a methyl group, or an ethyl group are preferred, compounds comprising a hydrogen atom or a methyl group are more preferred, and compounds comprising a hydrogen atom are particularly preferred. Specific examples of cycloocta-1,5-diene compounds of general formula (1) include cycloocta-1,5-diene, 1-chlorocycloocta-1,5-diene, 1,5-dichlorocycloocta-1,5-diene, 1-methylcycloocta-1,5-diene, and 1,5-dimethylcycloocta-1,5-diene.

[0035] The proportion of diene units in the polymer chain is not particularly limited and may be 0 mol%, but is preferably 0.1 mol% or more, more preferably 1 mol% or more, and may also be 100 mol%. When the above proportion is 1 mol% or more, a complexed polymer with excellent elastomeric properties can be obtained.

[0036] The aforementioned olefin unit is a monomer unit derived from an olefin compound. The olefin compound used as a monomer preferably has 2 to 10 carbon atoms. Specific examples of such olefin compounds include α-olefins such as ethylene, propylene, 1-pentene, 1-hexene, 1-heptene, and 1-octene, and heteroatom-substituted alkene compounds such as vinyl pivalate, 1-phenylthioethene, and N-vinylpyrrolidone.

[0037] Furthermore, the olefin compound may have two or more functional groups containing oxygen atoms. An example of an olefin compound having two or more functional groups containing oxygen atoms is the following general formula (2): [ka] [In the formula, R 2 Each of these is independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms. Examples include 5-cyclooctene-1,2-diol compounds represented by [ ]. As the 5-cyclooctene-1,2-diol compound of general formula (2), commercially available compounds may be used, or compounds synthesized according to known methods may be used. From the viewpoint of availability, etc., R 2 However, compounds comprising a hydrogen atom, a halogen atom, a methyl group, or an ethyl group are preferred, compounds comprising a hydrogen atom or a methyl group are more preferred, and compounds comprising a hydrogen atom are particularly preferred. Specific examples of 5-cyclooctene-1,2-diol compounds of general formula (2) include 5-cyclooctene-1,2-diol.

[0038] The proportion of olefin units in the polymer chain is not particularly limited and may be 0 mol%, but is preferably 1 mol% or more, and may also be 100 mol%.

[0039] The polymer chain can be synthesized by polymerizing or copolymerizing the diene compound and / or the olefin compound.

[0040] Furthermore, the polymer chain may contain units derived from other monomers copolymerizable with the diene compound and / or the olefin compound. Examples of such units derived from other monomers include aromatic vinyl units. The proportion of units derived from other monomers in the polymer chain is not particularly limited and may be 0 mol%, but in one embodiment, it is preferably 1 mol% or more, and preferably 50 mol% or less. The aforementioned aromatic vinyl unit is a monomer unit derived from an aromatic vinyl compound. The aromatic vinyl compound refers to an aromatic compound substituted with at least one vinyl group. The aromatic vinyl compound as a monomer preferably has 8 to 10 carbon atoms. Specific examples of such aromatic vinyl compounds include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2-ethylstyrene, 3-ethylstyrene, and 4-ethylstyrene.

[0041] (functional group) The complexed polymer of the present invention contains two or more functional groups containing oxygen atoms bonded to the main chain and / or side chains of the polymer chain. At least two of these functional groups have oxygen atoms bonded to adjacent carbon atoms on the main chain and / or side chains of the polymer chain, and are complexed with metal ions of elements from groups 3 to 12 of the periodic table. The inclusion of oxygen atoms in the functional groups and their complexation with metal ions of elements from groups 3 to 12 of the periodic table strengthens the bond between the functional groups and the metal ions. Furthermore, because the oxygen atoms in one functional group and the oxygen atoms in another functional group are bonded to adjacent carbon atoms on the main chain and / or side chains of the polymer chain, two functional groups can easily complex with one metal ion, forming high-strength crosslinks and improving the tensile strength (TB) and elongation (EB) at cleavage of the complexed polymer. Furthermore, the polymer chain includes sites where multiple carbon atoms are directly bonded, and at least two of the functional groups have oxygen atoms in the functional group bonded to carbon atoms (carbon atoms in the sites where multiple carbon atoms are directly bonded to the polymer chain). It can also be said that the number of carbon atoms between the oxygen atom in one functional group and the oxygen atom in the other functional group is 2, or that the functional group has vicinal oxygen atoms.

[0042] In the complexed polymer of the present invention, the bond dissociation energy between the metal ion and the functional group is preferably 100 kJ / mol or more, more preferably 200 kJ / mol or more, even more preferably 250 kJ / mol or more, and preferably 500 kJ / mol or less. When the bond dissociation energy is 100 kJ / mol or more, a higher strength crosslink can be formed, and the tensile strength (TB) and elongation (EB) at cleavage of the complexed polymer are further improved. Furthermore, when the bond dissociation energy is 500 kJ / mol or less, the bond between the metal ion and the functional group can be broken more easily, and the complexed polymer can be recycled more easily.

[0043] In this invention, the bond dissociation energy between the metal ion and the functional group is calculated at the M06 / 6-31G(d,p) / / B3PW91-D3 / 6-31G(d,p) level or the M06 / 6-31G(d,p) level in a vacuum. It is assumed that the metal ion and the functional group form an ionic aggregate. Gaussian09 or GRRM14 can be used to calculate this bond dissociation energy.

[0044] In the complexed polymer of the present invention, it is preferable that the metal ion and the functional group are bonded by a coordination bond. A coordination bond provides sufficient reversibility to the bond between the metal ion and the functional group. Furthermore, a coordination bond facilitates the formation of a sufficiently strong bond between the metal ion and the functional group, and also facilitates the fluidization of the complexed polymer by heating, making remolding easier and further improving the recyclability of the complexed polymer.

[0045] Examples of functional groups containing oxygen atoms include hydroxyl groups, carboxyl groups, or functional groups derived from these. For example, when complexing with metal ions, hydroxyl groups and carboxyl groups may lose a proton and cease to exist as hydroxyl groups or carboxyl groups. Therefore, functional groups derived from hydroxyl groups include hydroxyl groups and groups in which a proton has been removed from a hydroxyl group, and functional groups derived from carboxyl groups include carboxyl groups and groups in which a proton has been removed from a carboxyl group.

[0046] In the complexed polymer of the present invention, it is preferable that at least two of the functional groups have oxygen atoms bonded to the metal ions. Bonding of oxygen atoms in the functional groups to metal ions allows for the formation of stronger crosslinks, further improving the tensile strength (TB) and elongation (EB) at cleavage of the complexed polymer.

[0047] In the complexed polymer of the present invention, it is preferable that at least two of the oxygen atom-containing functional groups are derived from hydroxyl groups. Functional groups derived from hydroxyl groups readily complex with metal ions, enabling the formation of stronger crosslinks, and further improving the tensile strength (TB) and elongation (EB) at cleavage of the complexed polymer.

[0048] In the complexed polymer of the present invention, it is preferable that the functional group is derived from a compound having a functional group containing an oxygen atom. Examples of compounds having a functional group containing an oxygen atom include the 5-cyclooctene-1,2-diol compound represented by the above general formula (2), thioglycerol, and the like.

[0049] In the complexed polymer of the present invention, the functional groups are preferably bonded in an amount of 0.1 to 40 mol% relative to the monomer units in the polymer chain, and more preferably in an amount of 0.1 to 30 mol%. When the functional groups are bonded in an amount of 0.1 mol% or more relative to the monomer units in the polymer chain, high-strength crosslinking can be formed, further improving the tensile strength (TB) and elongation (EB) at cleavage of the complexed polymer. Furthermore, when the functional groups are bonded in an amount of 40 mol% or less relative to the monomer units in the polymer chain, a complexed polymer with sufficient elastomeric properties is easily obtained.

[0050] (Metal ions) In the complexed polymer of the present invention, the metal ion that complexes with the functional group is a metal ion of an element from groups 3 to 12 of the periodic table. Specifically, elements in Group 3 of the periodic table include scandium and yttrium. Other elements in Group 4 of the periodic table include titanium and zirconium. Other elements in Group 5 of the periodic table include vanadium and niobium. Other elements in Group 6 of the periodic table include chromium, molybdenum, and tungsten. Other elements in Group 7 of the periodic table include manganese and rhenium. Other elements in Group 8 of the periodic table include iron, ruthenium, and osmium. Other elements in Group 9 of the periodic table include cobalt, rhodium, and iridium. Other elements in Group 10 of the periodic table include nickel, palladium, and platinum. Other elements in Group 11 of the periodic table include copper and silver. Other elements in Group 12 of the periodic table include zinc, among others. Metal ions of elements in groups 3-12 of the periodic table tend to form strong bonds with functional groups containing oxygen atoms. Furthermore, regarding metal ions of elements in groups 3-12 of the periodic table, the valency of the ions is not particularly limited and can take on any valency that each element can possess.

[0051] The metal ion is preferably selected from metal ions of elements in groups 7 to 12 of the periodic table. When the metal ion is a metal ion of an element in groups 7 to 12 of the periodic table, the bond with the functional group containing an oxygen atom tends to become stronger, and a higher strength crosslink can be formed.

[0052] The metal ions are preferably selected from metal ions of elements in the fourth and fifth periods of the periodic table. Metal ions of elements in the fourth and fifth periods of the periodic table have high coordination power to functional groups containing oxygen atoms, improving the bond dissociation energy between the metal ions and functional groups, and further improving the tensile strength (TB) and elongation (EB) at cleavage of the complexed polymer.

[0053] The aforementioned metal ion is preferably at least one selected from the group consisting of iron ions, copper ions, and zinc ions. Iron ions, copper ions, and zinc ions tend to bond particularly strongly with functional groups containing oxygen atoms, and can form a stronger cross-linked structure. The valency of the iron ion is divalent (Fe 2+ ) or trivalent (Fe 3+ ) is preferable.

[0054] In the complexed polymer of the present invention, the metal ions are preferably complexed by adding a metal salt to the polymer chain to which the functional groups are bonded. In this case, a complexed polymer can be easily obtained, and a high-strength crosslink can be formed. The form of the metal salt to be added is not particularly limited, and may be a hydrate, for example. Furthermore, the amount of metal salt added is preferably in the range of 0.1 to 10 parts by mass, and more preferably in the range of 0.1 to 5 parts by mass, per 100 parts by mass of polymer chain.

[0055] Examples of the aforementioned metal salts include metal halides, metal sulfates, metal nitrates, etc., with metal halides being preferred among these. Metal halides are easy to handle and can form high-strength crosslinks more easily.

[0056] Furthermore, examples of metal halides include metal fluorides, metal chlorides, metal bromides, and metal iodides, and among these, metal chlorides are preferred. Metal chlorides are easy to handle and can form high-strength crosslinks more easily.

[0057] Furthermore, it is preferable that the metal salt is something other than a metal oxide, metal carbonate, or fatty acid metal salt. Metal salts other than metal oxides, metal carbonates, and fatty acid metal salts readily form further coordinate bonds (further complexes) with functional groups containing oxygen atoms. Therefore, using metal salts other than these makes it easier to form crosslinks by coordinate bonds.

[0058] Examples of the aforementioned metal salts include FeCl2, FeCl2·4H2O, FeCl3, FeCl3·6H2O, CuCl2, CuCl2·2H2O, and ZnCl2. Furthermore, the metal salt may be used individually or in combination of two or more types.

[0059] <Method for manufacturing complexed polymers> The method for producing the complexed polymer of the present invention is the method for producing the complexed polymer described above. The present invention provides a method for producing a complexed polymer, characterized by reacting a polymer chain to which the functional groups are bonded with a metal salt containing elements from groups 3 to 12 of the periodic table. According to the method for producing the complexed polymer of the present invention, the complexed polymer can be easily obtained.

[0060] Here, the molar ratio of the functional group attached to the polymer chain to the metal salt (functional group attached to the polymer chain / metal salt) is preferably 2 or more. When the molar ratio of the functional group attached to the polymer chain to the metal salt is 2 or more, the excess metal ions derived from the metal salt can be reduced, and the degradation of the complexed polymer caused by metal ions can be suppressed. From the viewpoint of suppressing the degradation of the complexed polymer, the molar ratio of the functional group attached to the polymer chain to the metal salt (functional group attached to the polymer chain / metal salt) is more preferably 4 or more, and from the viewpoint of increasing the crosslinking structure by metal ions, it is preferably 8 or less.

[0061] The polymer chain or the polymer chain to which the functional group is attached preferably has a weight-average molecular weight (Mw) of 300 to 1,000,000, and more preferably 1,000 to 1,000,000. When the weight-average molecular weight (Mw) is 1,000 or more, the tensile strength at break (TB) and elongation at break (EB) are improved, and when the weight-average molecular weight (Mw) is 1,000,000 or less, the processability is improved. In this specification, the weight-average molecular weight (Mw) is determined by gel permeation chromatography (GPC) using polystyrene as the standard substance.

[0062] Furthermore, in the complexation reaction between the polymer chain to which the functional group is attached and a metal salt (metal ion) containing elements from groups 3 to 12 of the periodic table, it is preferable to appropriately select reaction conditions such as temperature, pressure, and time according to the type of polymer chain to which the functional group is attached, the type of metal ion used, and its reactivity.

[0063] The complexed polymer of the present invention may be prepared in advance by synthesis or other means as described above, but it may also be generated during the rubber composition manufacturing process (in situ), as described in the section on the method of manufacturing the rubber composition later.

[0064] --A first method for producing polymer chains with attached functional groups-- The polymer chain to which the functional group is attached may be formed, for example, by ring-opening metathesis polymerization of a cycloocta-1,5-diene compound represented by the general formula (1) and a 5-cyclooctene-1,2-diol compound represented by the general formula (2). As an example, the reaction scheme for ring-opening metathesis polymerization when cycloocta-1,5-diene is used as the compound represented by the general formula (1) and 5-cyclooctene-1,2-diol is used as the compound represented by the general formula (2) is shown below. [ka]

[0065] The molar ratio of the cycloocta-1,5-diene compound represented by general formula (1) to the 5-cyclooctene-1,2-diol compound represented by general formula (2) is preferably in the range of 1:9 to 9:1 and can be appropriately selected depending on the purpose. In the aforementioned ring-opening metathesis polymerization, known catalysts can be used, such as transition metal complexes including titanium complexes, zirconium complexes, molybdenum complexes, ruthenium complexes, tantalum complexes, tungsten complexes, and rhenium complexes. Among these, transition metal-carbene complexes, such as Grubbs first-generation catalysts, Grubbs second-generation catalysts, and Hoveyda-Grubbs catalysts, are preferred. The structural formula of the Grubbs second-generation catalyst is as follows: [ka] It is expressed as and commercially available products can be used. The amount of catalyst used is preferably 0.001 to 10 mol%, more preferably 0.01 to 1 mol%, and particularly preferably 0.01 to 0.1 mol% per mole of the raw material monomer.

[0066] In the ring-opening metathesis polymerization described above, the reaction temperature is preferably -50°C to 180°C, more preferably -20°C to 100°C, and even more preferably -10°C to 80°C. The reaction time is preferably 1 to 24 hours, and the reaction pressure may be pressurized, depressurized, or atmospheric pressure, but atmospheric pressure is preferred. Furthermore, the reaction atmosphere is preferably an inert gas atmosphere such as nitrogen or argon. The ring-opening metathesis polymerization may be carried out in a solvent, and preferred solvents are those that are inert to the reaction, such as aliphatic halogen solvents such as dichloromethane, chloroform, and 1,2-dichloroethane; ether solvents such as diethyl ether, tetrahydrofuran, and dioxane; aromatic hydrocarbon solvents such as benzene, toluene, xylene, and mesitylene; aromatic halogen solvents such as monochlorobenzene and dichlorobenzene; and aliphatic hydrocarbon solvents such as hexane, heptane, octane, and cyclohexane.

[0067] --A second method for producing polymer chains with attached functional groups-- Furthermore, the polymer chain to which the functional group is attached may be formed by reacting a polymer chain with a compound having a functional group containing an oxygen atom. Here, the polymer chain can be synthesized by polymerizing or copolymerizing the diene compound and / or the olefin compound. Furthermore, it is preferable that the compound having the functional group containing the oxygen atom also has a functional group containing the sulfur atom. Compounds having a functional group containing an oxygen atom and a functional group containing a sulfur atom can be easily added to polymer chains.

[0068] Examples of the aforementioned sulfur atom-containing functional groups include thiol groups (also called "mercapto groups") and sulfide groups (also called "thioether groups"), with thiol groups being preferred. When a compound having a functional group containing an oxygen atom also has a thiol group as the sulfur atom-containing functional group, it becomes easier to further add it to the polymer chain.

[0069] The compound having a functional group containing an oxygen atom preferably has two or more hydroxyl groups as the functional group containing the oxygen atom. Furthermore, it is preferable that at least two of the hydroxyl groups in the compound having two or more hydroxyl groups are bonded to adjacent carbon atoms. That is, the compound having two or more hydroxyl groups is preferably a vicinal diol having a functional group containing a sulfur atom. By having at least two hydroxyl groups bonded to adjacent carbon atoms, the hydroxyl groups of the compound having hydroxyl groups attached to one polymer chain and the hydroxyl groups of the compound having hydroxyl groups attached to another polymer chain form multiple bonds with metal ions in close proximity, further improving the strength of the crosslinked structure.

[0070] Examples of compounds having two or more hydroxyl groups include 1-mercapto-1,2-ethanediol, 3-mercapto-1,2-propanediol (also called "thioglycerol" or "α-thioglycerol"), 2-mercapto-1,2-propanediol, 1-mercapto-1,2-propanediol, 3-mercapto-2-methyl-1,2-propanediol, 3-mercapto-2-ethyl-1,2-propanediol, 1-mercapto-2-methyl-1,2-propanediol, and 1-mercapto-2-ethyl-1,2-propanediol. Among these, thioglycerol is preferred.

[0071] --Other methods for producing polymer chains with attached functional groups-- The polymer chain to which the functional group is attached is not limited to the first and second manufacturing methods described above, but may be formed by other manufacturing methods. For example, a polymer chain having an epoxy group can be synthesized, and the epoxy group can be opened (hydrolyzed) to obtain a polymer chain in which two hydroxyl groups are bonded to adjacent carbon atoms.

[0072] <Rubber composition> The rubber composition of the present invention is characterized by containing the above-mentioned complexed polymer. Such rubber composition of the present invention exhibits improved tensile strength at break (TB) and elongation at break (EB).

[0073] A rubber composition according to one embodiment of the present invention contains the above-mentioned complexing polymer as a rubber component. The rubber composition of the present invention may also contain rubber components other than the above-mentioned complexing polymer, such as natural rubber (NR), synthetic diene rubber, and non-diene rubber. Examples of synthetic diene rubbers include synthetic isoprene rubber (IR), styrene-butadiene rubber (SBR), butadiene rubber (BR), styrene-isoprene rubber (SIR), chloroprene rubber (CR), ethylene-butadiene copolymer, and ethylene-styrene-butadiene copolymer. Examples of non-diene rubbers include silicone rubber, fluororubber, and urethane rubber. Furthermore, the rubber component of the rubber composition preferably contains 10% by mass or more of the complexing polymer, and may contain 100% by mass.

[0074] Furthermore, if the complexed polymer contains olefin units in its polymer chain but no diene units, it becomes a resin component. In this case, any rubber can be used as the rubber component of the rubber composition, and the above-mentioned natural rubber (NR), synthetic diene rubber, non-diene rubber, etc., can be used as the rubber component.

[0075] In addition to the complexing polymer and rubber components described above, the rubber composition of the present invention may also contain, in appropriate selection and in moderation, compounding agents commonly used in the rubber industry, such as fillers (carbon black, silica, etc.), softeners, waxes, stearic acid, antioxidants, silane coupling agents, zinc oxide, vulcanization accelerators, etc., within a range that does not impair the objectives of the present invention. Commercially available compounding agents can be suitably used. The rubber composition of the present invention preferably contains or does not contain a small amount (for example, 3 parts by mass or less) of sulfur and peroxide. Even when sulfur is present or not present, the rubber composition of the present invention may contain a vulcanization accelerator, and more preferably contains one. The vulcanization accelerator preferably contains a sulfenamide-based vulcanization accelerator.

[0076] In one embodiment of the rubber composition of the present invention, the amount of sulfur in the rubber composition is preferably 3 parts by mass or less, more preferably 0.3 parts by mass or less, per 100 parts by mass of the rubber component, and the amount of sulfur may be 0 parts by mass. Because such a rubber composition has a low sulfur content, it has fewer sulfur-derived crosslinked structures (SS bonds, CS bonds, etc.) that are difficult to cleave once formed, and is easy to recycle.

[0077] Furthermore, in another embodiment of the rubber composition of the present invention, the peroxide content in the rubber composition is preferably 3 parts by mass or less, more preferably 0.3 parts by mass or less, per 100 parts by mass of rubber component, and the peroxide content may be 0 parts by mass. Because such a rubber composition has a low peroxide content, it has fewer cross-linked structures (such as CC bonds) caused by peroxide that are difficult to cleave once formed, and is easy to recycle.

[0078] Furthermore, in another embodiment of the rubber composition of the present invention, it is preferable that the amount of sulfur in the rubber composition is 3 parts by mass or less per 100 parts by mass of rubber components, and the amount of peroxide in the rubber composition is 3 parts by mass or less per 100 parts by mass of rubber components, and it is even more preferable that the amount of sulfur in the rubber composition is 0.3 parts by mass or less, and the amount of peroxide in the rubber composition is 0.3 parts by mass or less per 100 parts by mass of rubber components. Because such a rubber composition has a low amount of sulfur and peroxide, it has fewer cross-linking structures (SS bonds, CS bonds, CC bonds, etc.) caused by sulfur and peroxides, and is easy to recycle.

[0079] Examples of the wax include paraffin wax and microcrystalline wax. The amount of the wax is not particularly limited, but is preferably in the range of 0.1 to 5 parts by mass, and more preferably 1 to 4 parts by mass, per 100 parts by mass of the rubber component.

[0080] The stearic acid content is not particularly limited, but is preferably in the range of 0.1 to 5 parts by mass, and more preferably 0.5 to 4 parts by mass, per 100 parts by mass of rubber component.

[0081] Examples of the aforementioned antioxidants include N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), 2,2,4-trimethyl-1,2-dihydroquinoline polymer (TMDQ), 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (AW), and N,N'-diphenyl-p-phenylenediamine (DPPD). The content of the antioxidant is not particularly limited, but is preferably in the range of 0.1 to 5 parts by mass, and more preferably 1 to 4 parts by mass, per 100 parts by mass of the rubber component.

[0082] The content of the zinc oxide is not particularly limited, but is preferably in the range of 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of the rubber component.

[0083] Examples of the vulcanization accelerator include sulfenamide-based vulcanization accelerators, guanidine-based vulcanization accelerators, thiazole-based vulcanization accelerators, thiram-based vulcanization accelerators, and dithiocarbamate-based vulcanization accelerators. The content of the vulcanization accelerator is not particularly limited, but is preferably in the range of 0.1 to 5 parts by mass, and more preferably in the range of 0.2 to 3 parts by mass, per 100 parts by mass of rubber component.

[0084] The rubber composition of the present invention can be used in various rubber products. Examples of rubber products include tires, rubber tracks, and seismic isolation rubber.

[0085] <Method for manufacturing rubber composition> The present invention provides a method for producing a rubber composition containing the complexing polymer described above. The complexing polymer may be generated during the rubber composition manufacturing process.

[0086] A method for producing a rubber composition according to one embodiment of the present invention involves mixing a polymer chain to which the functional group is bonded with a metal salt containing elements from groups 3 to 12 of the periodic table. training This process generates a complexed polymer. This method for producing the rubber composition offers excellent productivity because the complexing polymer can be prepared during the production of the rubber composition (kneading of the rubber composition). Furthermore, training In this case, any combination of the above-mentioned compounding agents may be incorporated simultaneously.

[0087] In the production of the rubber composition, the amount of metal salt blended is preferably 0.1 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the polymer chain to which the functional group is attached. When the amount of metal salt blended is 0.1 parts by mass or more per 100 parts by mass of the polymer chain to which the functional group is attached, the crosslinking structure due to metal ions increases, further improving the tensile strength (TB) and elongation (EB) at break of the rubber composition. Also, when the amount of metal salt blended is 10 parts by mass or less per 100 parts by mass of the polymer chain to which the functional group is attached, excess metal ions derived from the metal salt can be reduced, and degradation of the complexed polymer caused by metal ions can be suppressed.

[0088] The method for producing the rubber composition of the present invention is not limited to the method described above. For example, in another embodiment of the present invention, in the first step of kneading, a polymer chain and a compound having a functional group containing an oxygen atom are kneaded together to form a polymer chain to which the functional group is bonded. In another embodiment of the present invention, in the second and subsequent steps of kneading, a metal salt is added and kneaded together to complex the polymer chain to which the functional group is bonded, thereby forming a complexed polymer. Such a method for producing a rubber composition is highly productive because the complexed polymer can be prepared during the production of the rubber composition (kneading of the rubber composition).

[0089] Furthermore, in another embodiment of the present invention, a method for producing a rubber composition involves pre-forming the complexing polymer and incorporating the pre-formed complexing polymer during kneading. This method also allows for the simple production of a rubber composition containing the above-mentioned complexing polymer and offers excellent productivity.

[0090] Furthermore, in another embodiment of the present invention, a method for producing a rubber composition involves pre-preparing polymer chains to which functional groups are bonded, kneading the polymer chains to which the functional groups are bonded with an arbitrary compounding agent in the first stage of kneading, and then adding a metal salt and kneading it in the second stage and beyond of kneading to complex the polymer chains to which the functional groups are bonded, thereby forming a complexed polymer. This method for producing a rubber composition also allows for the simple production of a rubber composition containing the above-mentioned complexed polymer and offers excellent productivity. [Examples]

[0091] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to the following examples.

[0092] <Method for synthesizing polymer chains with attached functional groups> Using cycloocta-1,5-diene and 5-cycloocten-1,2-diol as monomers, ring-opening metathesis polymerization was performed according to macromoleculecules 2020, 53, 4121 to synthesize polymers containing hydroxyl groups. The synthesized polymer containing hydroxyl groups has a composition where cycloocta-1,5-diene units account for 80 mol% of the total polymer composition, and 5-cyclooctene-1,2-diol units account for 20 mol%.

[0093] <Manufacturing of rubber compositions> Rubber compositions were prepared by kneading according to the formulations shown in Tables 1, 2, and 3. The kneading process was carried out in two stages: first stage and second stage. In the examples, iron(II) chloride tetrahydrate was added during the second stage of kneading to form a complexed polymer. The first stage of kneading was performed at 110°C for 3 minutes, and the second stage was performed at 80°C for 1 minute and 30 seconds. The tensile strength at break (TB) and elongation at break (EB) of the obtained rubber compositions were measured using the following methods.

[0094] Furthermore, regarding Comparative Examples 2 and 3, training However, the rubber composition did not come together, and it was not possible to measure the tensile strength at break (TB) and elongation at break (EB). Furthermore, in the case of Comparative Example 4, since it is a functionalized polymer alone, training They did not do it. Furthermore, regarding the complexed polymer in the rubber compositions produced in Example 1 and Example 2, the bond dissociation energy between the iron ion and the oxygen-containing functional group (hydroxyl group) is approximately 218 kJ / mol.

[0095] (1) Measurement method for TB and EB Dumbbell-shaped test specimens conforming to JIS No. 7 were prepared from the rubber composition, and tensile tests were performed at room temperature (23°C) and high temperature (100°C) in accordance with JIS K6251 to measure the tensile strength at break (TB) and elongation at break (EB). In Table 1, the tensile strength at break (TB) and elongation at break (EB) of Comparative Example 1 at room temperature (23°C) are expressed in exponential terms, with the TB value set to 100. In Table 2, the tensile strength at break (TB) of Comparative Example 4 at room temperature (23°C) and high temperature (100°C) are expressed in exponential terms, with the TB value set to 100. In Table 3, the tensile strength at break (TB) and elongation at break (EB) of Comparative Example 1 at room temperature (23°C) are expressed in exponential terms, with the TB value set to 100. A larger exponential value indicates a greater tensile strength at break (TB) and elongation at break (EB).

[0096] [Table 1]

[0097] [Table 2]

[0098] [Table 3]

[0099] *1 Hydroxyl polymer: A polymer having a hydroxyl group synthesized by the method described above. *2 Butadiene rubber: Manufactured by Asahi Kasei Corporation, product name "Toughden (registered trademark) 2000R" *3 Stearic acid: Manufactured by Kao Corporation, product name "Lunaq S-70V" *4 Wax: Manufactured by Seiko Chemical Co., Ltd., product name "Suntight A" *5 Anti-aging agent 6PPD: N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine, manufactured by Ouchi Shinko Chemical Industry Co., Ltd., product name "Nocrac 6C" *6 FeCl2·4H2O: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. *7 Zinc oxide: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. *8 Vulcanization accelerator DPG: 1,3-diphenylguanidine, manufactured by Sumitomo Chemical Co., Ltd., trade name "Soccinol D" *9 Vulcanization accelerator CBS: N-cyclohexyl-2-benzothiazolyl sulfenamide, manufactured by Sanshin Chemical Industry Co., Ltd., product name "Sunceller CM-G" *10 Vulcanization accelerator DM: Di-2-benzothiazolyl disulfide, manufactured by Ouchi Shinko Chemical Industry Co., Ltd., trade name "Noxellar DM-P" *11 Sulfur: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. *12 α-thioglycerol: Manufactured by Tokyo Chemical Industry Co., Ltd.

[0100] Tables 1 and 3 show that the rubber compositions of the embodiments according to the present invention have improved tensile strength at break (TB) and elongation at break (EB) compared to a general sulfur-crosslinked rubber composition (Comparative Example 1). Furthermore, Table 2 shows that the rubber compositions of the examples according to the present invention exhibit improved tensile strength (TB) at room temperature and high temperature compared to the elastomer crosslinked by hydrogen bonding of diols (Comparative Example 4). [Industrial applicability]

[0101] The complexed polymer and rubber composition of the present invention can be used in various rubber products such as tires, rubber tracks, and seismic isolation rubber.

Claims

1. A polymer chain comprising diene units and / or olefin units, and two or more functional groups containing oxygen atoms bonded to the main chain and / or side chains of the polymer chain, At least two of the functional groups are such that the oxygen atom in the functional group is bonded to an adjacent carbon atom in the main chain and / or side chain of the polymer chain, and is complexed with a metal ion of an element from groups 7 to 12 of the periodic table. The bond dissociation energy between the metal ion and the functional group is 100 kJ / mol or more. A complexed polymer characterized in that at least two of the oxygen atom-containing functional groups are derived from hydroxyl groups.

2. The complexed polymer according to claim 1, wherein the metal ion and the functional group are bonded by a coordination bond.

3. The complexed polymer according to claim 1 or 2, wherein at least two of the functional groups have oxygen atoms in the functional groups bonded to the metal ions.

4. The complexed polymer according to any one of claims 1 to 3, wherein the metal ion is selected from metal ions of elements in the fourth and fifth periods of the periodic table.

5. The complexed polymer according to claim 4, wherein the metal ion is at least one selected from the group consisting of iron ions, copper ions, and zinc ions.

6. The complexed polymer according to any one of claims 1 to 5, wherein the functional group is bonded to the monomer units in the polymer chain in an amount of 0.1 to 40 mol%.

7. The complexed polymer according to any one of claims 1 to 6, wherein the metal ion is complexed by adding a metal salt to the polymer chain to which the functional group is bonded.

8. The complexed polymer according to claim 7, wherein the metal salt is a metal halide.

9. The complexed polymer according to claim 8, wherein the metal salt is a chlorinated metal.

10. The complexed polymer according to any one of claims 7 to 9, wherein the metal salt is other than a metal oxide, a metal carbonate salt, and a fatty acid metal salt.

11. A rubber composition characterized by comprising the complexing polymer described in any one of Claims 1 to 10.

12. A method for producing a complexed polymer according to any one of claims 1 to 10, A method for producing a complexed polymer, characterized by reacting a polymer chain to which the aforementioned functional groups are bonded with a metal salt containing elements from groups 7 to 12 of the periodic table.

13. The method for producing a complexed polymer according to claim 12, wherein the molar ratio of the functional group bonded to the polymer chain to the metal salt (functional group bonded to the polymer chain / metal salt) is 4 or more.

14. A method for producing the rubber composition according to claim 11, A method for producing a rubber composition, characterized by generating a complexed polymer by kneading a polymer chain to which the aforementioned functional groups are bonded with a metal salt containing elements from groups 7 to 12 of the periodic table.

15. The method for producing the rubber composition according to claim 14, wherein the amount of the metal salt added is 0.1 to 10 parts by mass per 100 parts by mass of the polymer chain to which the functional group is attached.

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