Polyisoprenoid and method for producing same

Abstract

The purpose of the present invention is to provide a polyisoprenoid that has an alkyne site. The present invention relates to a polyisoprenoid represented by formula (1). (1): R1C≡CR In formula (1), R1 represents a hydrogen atom or an organic group. R represents an organic chain that has a repeating unit represented by formula (2). A terminal of the organic chain may be a functional group having a hetero atom. (2): -(CH2-C(CH3)=CH-CH2)-

Description

Polyisoprenoids and methods for producing the same

[0001] The present invention relates to polyisoprenoids and methods for producing the same.

[0002] One way to improve tire fuel efficiency is to suppress the molecular motion of polymers. Therefore, research has been conducted on synthesizing polymers with reactive groups at their ends or side chains that enable crosslinking with fillers such as silica. Natural rubber lacks these reactive groups, making it incompatible with fillers. While the synthesis of polyisoprenoids with modified end structures has been reported, crosslinking with fillers is difficult with methyl groups or benzene rings.

[0003] Click reactions have been reported as one method for crosslinking polymers with each other or with fillers (for example, Non-Patent Document 1).

[0004] Clickable aqueous polymers and click-crosslinked aqueous polymers are disclosed, with polyurethane, polyester, and polyacrylate disclosed as the main chain constituting the aqueous polymer (for example, Patent Document 1). Also disclosed are multi-component silicone compositions that can be crosslinked by a click reaction, with silicone disclosed as the main chain (for example, Patent Document 2).

[0005] Japanese Patent Publication No. 2018-517802, Japanese Patent Publication No. 2010-037561

[0006] Masayuki Akahori et al., and two others, "Development of Innovative Crosslinking Technology for Rubber," Toyoda Gosei Technical Report, Toyoda Gosei Co., Ltd., published December 23, 2022, Vol. 64 2022, pp. 26-29.

[0007] The present invention aims to solve the aforementioned problems and provide a polyisoprenoid having an alkyne moiety.

[0008] This invention relates to a polyisoprenoid represented by the following formula (1). １ C≡CR (1) In formula (1), R １ represents a hydrogen atom or an organic group. R represents an organic chain having repeating units represented by the following formula (2). The end of the organic chain may be a functional group having a heteroatom. -(CH ２ -C(CH３ )=CH-CH ２ )-(2)

[0009] Since the polyisoprenoid of the present invention is a polyisoprenoid having an alkyne moiety, it is a novel polyisoprenoid expected to be used in various fields such as rubber compositions for tires.

[0010] It is a figure showing an example of the activity measurement result. It is a figure showing an example of the GPC result.

[0011] The present invention is based on the finding that a novel polyisoprenoid having an alkyne moiety can be suitably obtained by polymerizing isopentenyl diphosphate or the like using a prenyltransferase with a starting substrate having an alkyne moiety.

[0012] (Polyisoprenoid) The above polyisoprenoid is represented by the following formula (1). R １ C≡CR (1) In formula (1), R １ represents a hydrogen atom or an organic group. R represents an organic chain having a repeating unit represented by the following formula (2). The terminal of the organic chain may be a functional group having a hetero atom. -(CH ２ -C(CH ３ )=CH-CH ２ )-(2)

[0013] In formula (1), R １ represents a hydrogen atom or an organic group. In the present specification, an organic group means a group having 1 or more carbon atoms. Also, the site represented by C≡C is also referred to as an alkyne site.

[0014] The above-mentioned polyisoprenoid has a structure similar to natural rubber and exhibits high compatibility with rubber molecules. Furthermore, because the above-mentioned polyisoprenoid has an alkyne moiety, it can form crosslinks with fillers such as silica and interact strongly with them. Thus, because the above-mentioned polyisoprenoid has high compatibility with rubber and can form crosslinks with fillers such as silica, when incorporated into a rubber composition, a rubber composition in which rubber molecules and fillers are composited at a high level can be obtained. For example, if the rubber composition is a tire rubber composition, it is thought to suppress the movement of rubber molecules and contribute to the fuel efficiency of the tire. Moreover, because the above-mentioned polyisoprenoid has an alkyne moiety, it is possible to introduce various modifying groups and make it highly branched.

[0015] R in equation (1) １ The organic group is preferably a group having 1 to 12 carbon atoms, and more preferably a group having 1 to 6 carbon atoms. １ The organic group may be linear, branched, or have a cyclic structure. Suitable organic groups include alkyl groups and alkenyl groups, with alkyl groups being more preferred. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, n-hexyl, and cyclohexyl groups.

[0016] R in equation (1) １ It is particularly preferable that this represents a hydrogen atom. It is believed that the polyisoprenoid having click-reactive terminal alkyne groups (HC≡C-) allows for more favorable cross-linking with fillers such as silica, thereby effectively suppressing terminal motion.

[0017] R represents an organic chain having repeating units represented by formula (2) above. The organic chain may have repeating units other than those represented by formula (2) above, but it is preferable that the proportion of repeating units represented by formula (2) above among the repeating units of the organic chain is 50 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 99 mol% or more, and particularly preferably 100 mol%.

[0018] The organic chain represented by R may have an integer number of repeating units represented by formula (2) above (oligomer chain) from 2 to 24, or an integer number of 25 or more (polymer chain), but it is preferable to have an integer number of 25 to 50,000, more preferably 30 to 40,000, even more preferably 40 to 35,000, and particularly preferably 100 to 20,000.

[0019] The repeating unit represented by formula (2) above may be bonded in a trans configuration, a cis configuration, or a combination thereof. For example, it is preferable that the repeating unit represented by formula (2) above is bonded in the same manner (type), and it is preferable that it constitutes a repeat of trans configuration represented by formula (2A) below, or a repeat of cis configuration represented by formula (2B) below. In other words, it is preferable that the repeating unit represented by formula (2) above is represented by formula (2A) below, or by formula (2B) below.

[0020] Other repeating units than those represented by formula (2) above include, for example, those in which the methyl group at position 3 is replaced with a substituent other than a methyl group. Even when the above polyisoprenoid has such repeating units, it can be suitably produced by the polyisoprenoid production method described later.

[0021] The end of the organic chain represented by R in formula (1) may be a hydrocarbon group such as an alkyl group (e.g., a methyl group), an alkenyl group, or an aromatic group, or it may be a functional group having a heteroatom. The heteroatom is not particularly limited and examples include oxygen and nitrogen. The functional group having a heteroatom may have one heteroatom or multiple heteroatoms.

[0022] Examples of functional groups having heteroatoms include hydroxyl groups, formyl groups, carboxyl groups, alkoxycarboxyl groups, alkoxycarbonyl groups, or OPP groups, with hydroxyl groups, carboxyl groups, or OPP groups being preferred.

[0023] In this specification, OPP (OPP group) refers to a diphosphate group (a group represented by formula (A-1) below), which has three hydroxyl groups bonded to a phosphorus atom. However, in aqueous solution, some or all of these hydroxyl groups dissociate (for example, becoming a group represented by formula (A-2) below). In this specification, OPP is a concept that also includes groups in which some or all of the hydroxyl groups have dissociated.

[0024] In this specification, OPP may have some or all of its hydroxyl groups dissociated to form salts. Examples of salts include metal salts, ammonium salts, and organic amine salts.

[0025] The organic chain represented by R in formula (1) may have direct bonds between the carbon atoms of the alkyne moiety in formula (1) and the repeating unit represented by formula (2), or it may have divalent linking groups. Examples of divalent linking groups include divalent aliphatic hydrocarbon groups (e.g., alkylene groups, preferably with 1 to 8 carbon atoms), divalent aromatic hydrocarbon groups (e.g., arylene groups, preferably with 6 to 12 carbon atoms), alkylene oxy groups, -O-, -S-, and -SO ２ Examples include -, -N(R)- (R: alkyl group), -CO-, -NH-, -COO-, -CONH-, or combinations thereof. Among these, alkylene groups or alkylene oxy groups having 1 to 4 carbon atoms are preferred, alkylene groups or alkylene oxy groups having 1 to 2 carbon atoms are more preferred, and alkylene groups (methylene groups) or alkylene oxy groups (methylene oxy groups) having 1 carbon atom are even more preferred.

[0026] The above polyisoprenoid is preferably represented by the following formula (3): HC≡C-CH ２ -O-(CH ２ -C(CH ３ ) = CH - CH ２ ) ｎ -Y (3) In equation (3), Y represents a functional group having a heteroatom. n is an integer of 2 or more.

[0027] In formula (3), n may be an integer from 2 to 24 (oligomer chain) or an integer of 25 or more (polymer chain), but for example, an integer from 25 to 50000 is preferred, an integer from 30 to 40000 is more preferred, an integer from 40 to 35000 is even more preferred, and an integer from 100 to 20000 is particularly preferred. In formula (3), Y may represent a hydroxyl group, a formyl group, a carboxyl group, an alkoxycarboxyl group, an alkoxycarbonyl group, or an OPP group, and is more preferably a hydroxyl group, a carboxyl group, or an OPP group.

[0028] In equation (3), "CH ２ -C(CH ３ ) = CH - CH ２ The repeating units represented by " may be bonded in the trans form, the cis form, or a combination thereof. For example, it is preferable that the above repeating units are bonded in the same manner (type), and it is preferable that they constitute a repeat of trans bonds shown in the following formula (3A), or a repeat of cis bonds shown in the following formula (3B). In other words, the compound represented by formula (3) is preferably represented by the following formula (3A), or by the following formula (3B).

[0029] The above polyisoprenoid may also preferably be represented by, for example, the following formula (4): R １ C≡C-X-(CH ２ -C(CH ３ ) = CH - CH ２ ) ｎ -OPP (4) In formula (4), R １ R in formula (1) is １ It is similar to the above. X represents a direct bond or a divalent linking group. n is an integer greater than or equal to 2.

[0030] In formula (4), X preferably represents a divalent linking group. The divalent linking group of X may be a divalent aliphatic hydrocarbon group (e.g., alkylene group, preferably with 1 to 8 carbon atoms), a divalent aromatic hydrocarbon group (e.g., arylene group, preferably with 6 to 12 carbon atoms), an alkylene oxy group, -O-, -S-, -SO ２Examples include -, -N(R)- (R: alkyl group), -CO-, -NH-, -COO-, -CONH-, or combinations thereof. Among these, alkylene groups or alkylene oxy groups having 1 to 4 carbon atoms are preferred, alkylene groups or alkylene oxy groups having 1 to 2 carbon atoms are more preferred, and alkylene groups (methylene groups) or alkylene oxy groups (methylene oxy groups) having 1 carbon atom are even more preferred.

[0031] In formula (4), n may be an integer from 2 to 24 (oligomer chain) or an integer of 25 or more (polymer chain), but for example, an integer from 25 to 50000 is preferred, an integer from 30 to 40000 is more preferred, an integer from 40 to 35000 is even more preferred, and an integer from 100 to 20000 is particularly preferred.

[0032] In equation (4), "CH ２ -C(CH ３ ) = CH - CH ２ The repeating units represented by " may be bonded in the trans form, the cis form, or a combination thereof. For example, it is preferable that the above repeating units are bonded in the same manner (type), and it is preferable that they constitute a repeat of trans bonds shown in the following formula (4A), or a repeat of cis bonds shown in the following formula (4B). In other words, the compound represented by formula (4) is preferably represented by the following formula (4A) or the following formula (4B).

[0033] The polyisoprenoid described above preferably has a weight-average molecular weight (Mw) of 600 or more. The Mw of the polyisoprenoid is more preferably 2040 or more, and even more preferably 6800 or more. The Mw of the polyisoprenoid is preferably 2,720,000 or less, and more preferably 1,360,000 or less.

[0034] In this specification, Mw can be determined by converting the measured values ​​obtained by gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMULTIIPORE HZ-M manufactured by Tosoh Corporation) to standard polystyrene equivalent.

[0035] Specific examples of the above-mentioned polyisoprenoids include, for example, the polyisoprenoids represented by the following formula (Z1) or formula (Z2).

[0036] (In formula (Z1), R １ R in formula (1) is １ It is the same as above. X is the same as X in equation (4) above. m represents an integer from 0 to 10. n represents an integer greater than m and greater than or equal to 2. Y is the same as Y in equation (3) above.

[0037] (In formula (Z2), R １ R in formula (1) is １ It is the same as above. X is the same as X in equation (4) above. m represents an integer from 0 to 10. n represents an integer greater than m and greater than or equal to 2. Y is the same as Y in equation (3) above.

[0038] The polyisoprenoid represented by formula (Z1) has all isoprene units bonded in the trans configuration. The polyisoprenoid represented by formula (Z2) has isoprene units bonded in the trans-cis configuration (when m is an integer from 1 to 9), or all are bonded in the cis configuration (when m is 0).

[0039] At least one of the atoms or groups of atoms included in the ii portion of the above formulas (Z1) and (Z2) may be substituted by other atoms or groups of atoms, but it is preferable that they are not substituted.

[0040] Other atoms mentioned above include, for example, nitrogen atoms, oxygen atoms, sulfur atoms, silicon atoms, carbon atoms, and so on.

[0041] Other atomic groups mentioned above include nitrogen atom-containing groups, oxygen atom-containing groups, sulfur atom-containing groups, silicon atom-containing groups, carbon atom-containing groups, etc. Examples include acetoxy groups, alkoxy groups (preferably alkoxy groups having 1 to 3 carbon atoms, more preferably methoxy groups), hydroxyl groups, aryl groups (preferably phenyl groups), alkyl groups (preferably alkyl groups having 1 to 5 carbon atoms, more preferably ethyl groups, tert-butyl groups), acetyl groups, N-alkyl-acetamino groups (the alkyl group preferably has 1 to 5 carbon atoms), azide groups, etc.

[0042] The i portion in the above formulas (Z1) and (Z2) is a structure derived from the starting substrate, which is the compound represented by formula (5) described later. Therefore, the m in the above formulas (Z1) and (Z2) is the same as the number of repeating units represented by formula (7) in formula (5) described later.

[0043] The ii portion in formulas (Z1) and (Z2) above represents isoprene units attached to the substrate represented by formula (5) above, which is the starting substrate. Therefore, "n-m" in formulas (Z1) and (Z2) above corresponds to the number of isoprene units attached to the substrate represented by formula (5) above, which is the starting substrate.

[0044] In the above formulas (Z1) and (Z2), Y is preferably a hydroxyl group, a formyl group, a carboxyl group, an alkoxycarboxyl group, an alkoxycarbonyl group, or an OPP group, and more preferably a hydroxyl group, a carboxyl group, or an OPP group.

[0045] Because the above-mentioned polyisoprenoids have alkyne moieties, they can form crosslinks with fillers such as silica, as described above, and can also be modified by introducing various modifying groups and becoming highly branched. For example, by reacting polyisoprenoids with organic compounds or magnetic beads having functional groups such as azide groups, it is possible to introduce organic groups derived from the organic compounds or magnetic bead groups derived from the magnetic beads. Furthermore, by reacting multiple polyisoprenoids with organic compounds or magnetic beads having multiple functional groups such as azide groups, it is possible to form highly branched polyisoprenoids.

[0046] Magnetic beads are made of iron, cobalt, nickel, manganese, or oxides thereof (for example, Fe as an oxide of iron)２ O ３ Ya Fe ３ O ４ The material contains core particles which are magnetic materials such as ), and is usually provided with a coating layer around the core particles, with multiple functional groups such as azide groups on its surface. Examples of materials for the coating layer include water-soluble polymers such as polyglycidyl methacrylate. Examples of functional groups include azide groups, as well as amino groups, carboxyl groups, alkyne groups, hydroxyl groups, epoxy groups, and so on.

[0047] The magnetic beads preferably have an average particle diameter of 0.001 to 100 μm, more preferably 0.01 to 10 μm, and even more preferably 0.1 to 1 μm.

[0048] In this specification, the method for measuring the average particle size of magnetic beads is to use transmission electron microscopy (TEM) observation. Specifically, magnetic beads are photographed with a transmission electron microscope, and if the magnetic beads are spherical, the diameter of the sphere is defined as the particle size; if they are needle-shaped or rod-shaped, the shorter axis is defined as the particle size; if they are irregularly shaped, the average particle size from the center is defined as the particle size; and the average particle size of 100 fine particles is defined as the average particle size.

[0049] Examples of commercially available magnetic beads include FG beads (registered trademark) azido beads (manufactured by Tamagawa Seiki Co., Ltd.).

[0050] (Method for producing polyisoprenoids) The above polyisoprenoids are synthesized using prenyltransferase from a substrate represented by the following formula (5) and a compound represented by the following formula (6). １ C≡CR (5) In formula (5), R １ represents a hydrogen atom or an organic group. R represents an organic chain having repeating units represented by the following formula (7). The ends of the organic chain are OPP. - (CH ２ -C(CH ３ ) = CH - CH ２ ) - (7)

[0051] Using the substrate represented by formula (5) above as an initiating substrate, the compound represented by formula (6) above is polymerized onto the initiating substrate using prenyltransferase, a naturally occurring oligomer-forming enzyme, to obtain a polyisoprenoid having a click-reaction functional group.

[0052] First, let's explain the substrate represented by formula (5) above. R in formula (5) １ The organic group is preferably a group having 1 to 12 carbon atoms, and more preferably a group having 1 to 6 carbon atoms. R in formula (5) １ The organic group may be linear, branched, or have a cyclic structure. Suitable organic groups include alkyl groups and alkenyl groups, with alkyl groups being more preferred. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, n-hexyl, and cyclohexyl groups.

[0053] R in equation (5) １ It is particularly preferable that this represents a hydrogen atom.

[0054] R represents an organic chain having repeating units represented by formula (7) above. The organic chain preferably has an integer number of repeating units represented by formula (7) above, from 1 to 10, and more preferably an integer number of from 2 to 8.

[0055] The repeating unit represented by formula (7) above may be a trans-type repeating unit, a cis-type repeating unit, or a combination thereof. For example, it is preferable that the repeating units represented by formula (7) above are bonded in the same manner (type), and it is preferable that they constitute a repeat of a trans-type bond shown in formula (7A) below, or a repeat of a cis-type bond shown in formula (7B) below.

[0056] The organic chain may have repeating units other than the repeating unit represented by formula (7) above, but it is preferable that it does not have repeating units other than the repeating unit represented by formula (7) above.

[0057] In equation (5), the end of the organic chain of R is OPP.

[0058] The organic chain represented by R in formula (5) may have direct bonds between the carbon atoms of the alkyne moiety in formula (5) and the repeating unit represented by formula (7), or it may have divalent linking groups. Examples of divalent linking groups include divalent aliphatic hydrocarbon groups (e.g., alkylene groups, preferably with 1 to 8 carbon atoms), divalent aromatic hydrocarbon groups (e.g., arylene groups, preferably with 6 to 12 carbon atoms), alkylene oxy groups, -O-, -S-, and -SO ２ Examples include -, -N(R)- (R: alkyl group), -CO-, -NH-, -COO-, -CONH-, or combinations thereof. Among these, alkylene groups or alkylene oxy groups having 1 to 4 carbon atoms are preferred, alkylene groups or alkylene oxy groups having 1 to 2 carbon atoms are more preferred, and alkylene groups (methylene groups) or alkylene oxy groups (methylene oxy groups) having 1 carbon atom are even more preferred.

[0059] The substrate represented by formula (5) above is preferably represented by, for example, the following formula (8). １ C≡C-X-(CH ２ -C(CH ３ ) = CH - CH ２ ) ｍ -OPP (8) In formula (8), R １ represents a hydrogen atom or an organic group. X represents a direct bond or a divalent linking group. m is an integer from 1 to 10.

[0060] R in equation (8) １ R in equation (1) is １ The same applies. In formula (8), X preferably represents a divalent linking group. Possible divalent linking groups for X include divalent aliphatic hydrocarbon groups (e.g., alkylene groups, preferably with 1 to 8 carbon atoms), divalent aromatic hydrocarbon groups (e.g., arylene groups, preferably with 6 to 12 carbon atoms), alkylene oxy groups, -O-, -S-, and -SO ２Examples include -, -N(R)- (R: alkyl group), -CO-, -NH-, -COO-, -CONH-, or combinations thereof. Among these, alkylene groups or alkylene oxy groups having 1 to 4 carbon atoms are preferred, alkylene groups or alkylene oxy groups having 1 to 2 carbon atoms are more preferred, and alkylene groups (methylene groups) or alkylene oxy groups (methylene oxy groups) having 1 carbon atom are even more preferred.

[0061] In equation (8), m is preferably an integer between 2 and 4.

[0062] Note that the repeating unit "CH" in equation (8) ２ -C(CH ３ ) = CH - CH ２ The repeating unit may be a trans-type repeating unit, a cis-type repeating unit, or a combination thereof. For example, it is preferable that the repeating units are bonded in the same manner (type), and it is preferable that they constitute a repeat of trans-type bonds shown in the following formula (8A), or a repeat of cis-type bonds shown in the following formula (8B). In other words, it is preferable that the substrate represented by formula (8) is either the substrate represented by the following formula (8A) or the substrate represented by the following formula (8B).

[0063] In polymerization using prenyltransferase, the alkyne moiety and other parts of the substrate represented by formula (5) above do not react. The reason for this is not entirely clear, but it is thought that prenyltransferase adsorbs to the structure of part I of formula (I) below of the substrate, and is relatively insensitive to the structure of other parts.

[0064] The above manufacturing method may use, in addition to the compound represented by formula (6), other compounds having a heteroatom-containing functional group (other compounds) as the compound to be polymerized onto the substrate. For example, the compound represented by the following formula (Y) (R-IPP) may be used. (In formula (Y), R represents a group other than a methyl group.)

[0065] In formula (Y), R is not particularly limited as long as it is a group other than a methyl group, but examples include nitrogen atom-containing groups, oxygen atom-containing groups, sulfur atom-containing groups, silicon atom-containing groups, carbon atom-containing groups (except for the methyl group), and specifically, examples include acetoxy groups, alkoxy groups, hydroxyl groups, aryl groups, alkyl groups (except for the methyl group), acetyl groups, N-acetylacetamino groups, azide groups, amino groups, mercapto groups, etc.

[0066] The compound represented by the above formula (Y) can be produced by a person skilled in the art, for example, by referring to the method described in the examples of International Publication No. 2014 / 042027.

[0067] The above polyisoprenoid is obtained by synthesis (biosynthesis) from a substrate represented by formula (5), a compound represented by formula (6), and, if necessary, other compounds.

[0068] A method for synthesizing (biosynthesizing) the polyisoprenoid from the substrate represented by formula (5), the compound represented by formula (6), and optionally the other compounds mentioned above can be, for example, a method using an enzyme having prenyltransferase activity. Specifically, the substrate represented by formula (5) and the compound represented by formula (6), which is a monomer to be polymerized onto the substrate, can be reacted in the presence of an enzyme having prenyltransferase activity. Note that the substrate represented by formula (5), the compound represented by formula (6), and the other compounds may each be the same compound, or multiple compounds may be used.

[0069] It is preferable to use only the compound represented by formula (6) above as the monomer to polymerize with the substrate represented by formula (5) above.

[0070] In this specification, prenyltransferase refers to an enzyme that has the activity to catalyze a reaction in which isoprene units (e.g., isopentenyl diphosphate) are sequentially linked to an allyl substrate (e.g., allyl diphosphate). By using prenyltransferase, it is possible to catalyze the condensation reaction between the substrate represented by formula (5) and the compound represented by formula (6) and synthesize a new substrate with one additional isoprene unit. As described above, even with a polymerizable compound (R-IPP) represented by formula (Y) in which, for example, the methyl group at position 3 is substituted with a desired group, the polyisoprenoid can be produced using prenyltransferase while sufficiently suppressing side reactions.

[0071] Many types of prenyltransferases have already been identified. One preferred form of the prenyltransferase is a cis-type prenyltransferase, which extends the prenyl chain into a Z-type (where the newly added isoprene units form a cis structure). Examples of the above-mentioned cis-type prenyltransferases include Z-nonaprenyl diphosphate synthase (Ishii, K. et al., (1986) Biochem, J., 233, 773.), undecaprenyl diphosphate synthase (Takahashi, I. and Ogura, K. (1982) J. Biochem., 92, 1527.; Keenman, M.V. and Allen, C.M. (1974) Arch. Biochem. Biophys., 161, 375.), and Z-farnesyl diphosphate synthase (Identification of a short (C-15) chain Z-isoprenyl diphosphate). Synthase and a homological long (C-50) chain isoprenyl diphosphate synthase in Mycobacterium tuberculosis, Schulbach, MC., et al. JOURNAL OF BIOLOGICAL CHEMISTRY, 275(30), 22876-22881(2000)), Dehydrodochylichyl diphosphate synthase (Identification of human dehydrodochylichyl diphosphate synthase gene) Endo, Shota. et al. Examples include *Biochimica Et Biophysica Acta (BBA), 1625(3), (2003) pp. 291-295.*. It is also preferable that the above-mentioned cis-type prenyltransferase is a mutant of tomato-derived neryl phosphate synthase (NDPS1) or a cis-type prenyltransferase derived from rubber-producing plants such as rubber tree, Russian dandelion, or guayule. By using a cis-type prenyltransferase as the prenyltransferase, the prenyl group can be extended in a cis structure.

[0072] It is also preferable that the above-mentioned prenyltransferase is a trans-type prenyltransferase that elongates the prenyl chain into an E-type (newly added isoprene unit in a trans structure). Examples of the above-mentioned trans-type prenyltransferase include farnesyl diphosphate synthase, geranylgeranyl diphosphate synthase, hexaprenyl diphosphate synthase, heptaprenyl diphosphate synthase, octaprenyl diphosphate synthase, decaprenyl diphosphate synthase, etc. It is also preferable that the above-mentioned trans-type prenyltransferase is a mutant of sapodilla-derived transprenyltransferase (MztPT2). By using a trans-type prenyltransferase as the prenyltransferase, the prenyl group can be elongated in a trans structure.

[0073] Since the maximum number of isoprene units that can be produced by each enzyme and the direction of prenyl chain elongation (trans structure, cis structure) are determined, the enzyme used should be changed according to the desired number of isoprene units and direction of prenyl chain elongation. Note that the direction of prenyl chain elongation (trans structure, cis structure) of polyisoprenoids is not particularly limited. That is, the polyisoprenoid may be, for example, a polyisoprenoid in which all isoprene units are bonded in the trans form (for example, the polyisoprenoid represented by formula (Z1) above), a polyisoprenoid in which isoprene units are bonded in the trans-cis form (for example, the polyisoprenoid represented by formula (Z2) above when m is an integer from 1 to 9), a polyisoprenoid in which isoprene units are bonded in the trans-cis-trans form, or a polyisoprenoid in which all isoprene units are bonded in the cis form (for example, the polyisoprenoid represented by formula (Z2) above when m is 0).

[0074] All organisms on Earth possess the above-mentioned prenyltransferase, but examples of organisms that possess the above-mentioned prenyltransferase include Micrococcus luteus B-P26, Escherichia coli, Saccharomyces cerevisiae, Arabidopsis thaliana, Hevea brasiliensis, Periploca sepium, and Bacillus stearothermophilus. Suitable examples include Steaothermophilus, Sulfolobus acidocaldarius (ATCC49426), Homo sapiens, Sonchus oleracers L., Taraxacum officinale, and Helianthus annuus.

[0075] In the above manufacturing method, a mutant enzyme having improved enzymatic activity toward the substrate represented by formula (5) may be used as the prenyltransferase. When using a mutant enzyme, a transformed organism (transformer) that expresses the mutant enzyme can be produced by genetic engineering techniques. Specifically, a person skilled in the art can easily produce a mutant enzyme having improved enzymatic activity toward the substrate represented by formula (5) by referring to the method described in Japanese Patent Application Publication No. 2012-036360.

[0076] The polyisoprenoid is obtained by reacting the substrate represented by formula (5) with the compound represented by formula (6) in the presence of prenyltransferase. The presence of prenyltransferase means a situation in which a culture of the above organism, an organism isolated from the culture, a processed product of the organism, an enzyme purified from the culture or the organism, a culture of an organism transformed to express prenyltransferase by genetic engineering (transformed organism), an organism isolated from the culture, a processed product of the organism, an enzyme purified from the culture or the organism, etc. An organism transformed to express prenyltransferase can be produced by conventionally known genetic engineering methods by those skilled in the art.

[0077] To obtain the organism described above, it is sufficient to culture the organism in a suitable culture medium. The culture medium is not particularly limited as long as it allows the organism to grow; a standard culture medium containing a carbon source, nitrogen source, inorganic ions, and, if necessary, organic nutrients will suffice.

[0078] For example, any of the above organisms can be used as a carbon source if available. Specifically, sugars such as glucose, fructose, maltose, amylose, and sucrose; alcohols such as sorbitol, ethanol, and glycerol; organic acids such as fumaric acid, citric acid, acetic acid, and propionic acid, and their salts; carbohydrates such as paraffin, or mixtures thereof can be used.

[0079] As nitrogen sources, ammonium salts of inorganic salts such as ammonium sulfate and ammonium chloride, ammonium salts of organic acids such as ammonium fumarate and ammonium citrate, nitrates such as sodium nitrate and potassium nitrate, organic nitrogen compounds such as peptone, yeast extract, meat extract, and corn steep liquor, or mixtures thereof can be used.

[0080] In addition, inorganic salts, trace metal salts, vitamins, hormones, and other nutrients commonly used in culture media can be mixed in as appropriate.

[0081] There are no particular restrictions on the culture conditions; for example, the culture can be carried out for 12 to 480 hours under aerobic conditions, with a pH of 5 to 8 and a temperature of 10 to 60°C, while appropriately controlling the pH and temperature.

[0082] The culture of the above organisms refers, for example, to a culture medium obtained by culturing the organisms under the above-described culture conditions, or to a culture filtrate (culture supernatant) obtained by separating the organisms (organisms) from the culture medium by filtration or the like. Furthermore, the organisms separated from the above cultures refer, for example, to organisms (organisms) separated from the culture medium by filtration, centrifugation or the like.

[0083] Examples of the processed biological material mentioned above include, for example, a homogenized biological material obtained by homogenizing the biological material separated from the culture, or a biological material that has been ultrasonically treated.

[0084] The enzyme purified from the culture or organism mentioned above refers to an enzyme obtained by performing a known purification operation such as salting out, ion exchange chromatography, affinity chromatography, or gel filtration chromatography on the enzyme present in the culture or organism. The purity of the purified enzyme is not particularly limited.

[0085] The polyisoprenoid can be obtained by reacting the substrate represented by formula (5) with the compound represented by formula (6) in the presence of prenyltransferase. Specifically, the reaction can be carried out by mixing the substrate represented by formula (5), the compound represented by formula (6), and prenyltransferase, for example, by adding a culture of the organism or purified enzyme to a solution containing the substrate represented by formula (5) and the compound represented by formula (6). The reaction temperature can be, for example, 20 to 60°C, the reaction time can be, for example, 0.1 to 16 hours, and the pH can be, for example, 5 to 8. Conventional pH adjusters, buffers such as Tris-HCl Buffer, etc., can be used as appropriate to adjust and maintain the pH. In addition, magnesium chloride, surfactants, 2-mercaptoethanol, dithiothreitol (DTT), etc., may be added as needed.

[0086] The polyisoprenoid obtained by the above reaction typically has an OPP group or a hydroxyl group at the end of the organic chain represented by R in formula (1), and at Y in formulas (3), (Z1), and (Z2). The OPP group is an OPP group derived from the compound represented by formula (6) or R-IPP. Furthermore, the OPP group is readily hydrolyzed, and a hydroxyl group is generated when the OPP group is hydrolyzed. Therefore, typically, the end of the organic chain represented by R in formula (1), and at Y in formulas (3), (Z1), and (Z2), are either an OPP group or a hydroxyl group. Furthermore, a polyisoprenoid in which the end of the organic chain represented by R in formula (1), formula (3), formula (Z1), and formula (Z2) is a formyl group can be obtained, for example, by oxidizing a polyisoprenoid in which the end of the organic chain represented by R in formula (1), formula (3), formula (Z1), and formula (Z2) is an OPP group. Furthermore, a polyisoprenoid in which the end of the organic chain represented by R in formula (1), formula (3), formula (Z1), and formula (Z2) is a carboxyl group can be obtained, for example, by oxidizing a polyisoprenoid in which the end of the organic chain represented by R in formula (1), formula (3), formula (Z1), and formula (Z2) is an OPP group. Furthermore, polyisoprenoids in which the end of the organic chain represented by R in formula (1), Y in formula (3), formula (Z1), and formula (Z2) is an alkoxycarboxyl group, and polyisoprenoids in which the end of the organic chain represented by R in formula (1), Y in formula (3), formula (Z1), and formula (Z2) is an alkoxycarbonyl group can be obtained, for example, by carboxylating a polyisoprenoid in which the end of the organic chain represented by R in formula (1), Y in formula (3), formula (Z1), and formula (Z2) is an OPP group using the method described above, and then esterifying it.

[0087] Since the above polyisoprenoids are obtained by biosynthesis using prenyltransferase, they can be used with consideration for the depletion of petroleum resources and environmental issues.

[0088] Furthermore, from the perspective of synthesizing long-chain polyisoprenoids, natural rubber latex can also be used as a source of prenyltransferase.

[0089] It has long been known that natural rubber latex (especially natural rubber latex derived from the Para rubber tree) contains prenyltransferase and other rubber extension factors that catalyze the condensation reaction between isoprene oligomers and isopentenyl diphosphate, sequentially linking isopentenyl diphosphate to the isoprene oligomers in a Z-shape (the newly added isoprene units have a cis structure) to produce natural polyisoprene.

[0090] Furthermore, it is known that some plants contain prenyltransferase and other rubber extension factors that catalyze the condensation reaction between isoprene oligomers and isopentenyl diphosphate, sequentially linking isopentenyl diphosphate to the isoprene oligomers in an E-type (newly added isoprene units in a trans structure) manner, thereby producing naturally occurring polyisoprene.

[0091] As described above, in the above manufacturing method, long-chain polyisoprenoids can be produced by using natural rubber latex and prenyltransferase or other rubber extension factors that produce naturally occurring polyisoprene. That is, a method for synthesizing (biosynthesizing) the above polyisoprenoid from the substrate represented by formula (5), the compound represented by formula (6), and optionally the above-mentioned other compounds can be, for example, carried out using prenyltransferase or other rubber extension factors contained in natural rubber latex. Alternatively, the method may be carried out using prenyltransferase or other rubber extension factors cloned from natural rubber latex.

[0092] In other words, the substrate represented by formula (5), the compound represented by formula (6), and optionally the other compounds can be reacted in the presence of the enzyme and / or the rubber extension factor. Specifically, for example, the reaction can be carried out by adding natural rubber latex, an enzyme isolated from natural rubber latex, a rubber extension factor, etc., to a solution containing the substrate represented by formula (5), the compound represented by formula (6), and optionally the other compounds. The reaction temperature can be, for example, 10 to 60°C, the reaction time can be, for example, 1 to 72 hours, and the pH can be, for example, 6 to 8. Magnesium chloride, 2-mercaptoethanol, potassium fluoride, etc., can also be added as needed.

[0093] The origin of the above-mentioned natural rubber latex is not particularly limited and includes, for example, Hevea brasiliensis, Ficus elastica, Ficus lyrata, Ficus benjamina, Ficus religiosa, Ficus benghalensis, Lactarius volemus, Sonchus oleracers L., Taraxacum officinale, and Helianthus annuus. Among them, the Para rubber tree is preferred because the molecular weight of the rubber produced is large and the amount of rubber contained in the latex is high.

[0094] Natural rubber latex can be obtained, for example, by making groove-like cuts (tapping) in the trunk of a rubber tree using a knife or similar tool, and then collecting the natural rubber latex that flows out from the severed milk ducts.

[0095] Sources of prenyltransferase isolated from natural rubber latex include, for example, serum, the bottom fraction layer, and the rubber layer separated by centrifugation of natural rubber latex. The rubber layer contains the above-mentioned prenyltransferase along with the rubber extension factors.

[0096] A preferred method for synthesizing (biosynthesizing) the polyisoprenoid from the substrate represented by formula (5) above, the compound represented by formula (6) above, and optionally the other compounds is, for example, a method that further uses a surfactant. It is believed that catalytic turnover is improved in the synthesis of the polyisoprenoid by promoting the separation of the product from the enzyme protein.

[0097] The surfactant is not particularly limited, and examples include nonionic surfactants and amphoteric surfactants. Among these, nonionic surfactants and amphoteric surfactants are preferably used, and amphoteric surfactants are particularly preferably used. In other words, it is also a preferred embodiment that the surfactant is an amphoteric surfactant. These surfactants may be used alone or in combination of two or more types.

[0098] Examples of the nonionic surfactants include polyoxyalkylene ether-based, polyoxyalkylene ester-based, polyhydric alcohol fatty acid ester-based, sugar fatty acid ester-based, alkyl polyglycoside-based, and polyoxyalkylene polyglucoside-based nonionic surfactants, as well as polyoxyalkylene alkylamines and alkyl alkanolamides. Among these, polyoxyalkylene ether-based nonionic surfactants and polyhydric alcohol fatty acid ester-based nonionic surfactants are preferred.

[0099] Examples of the polyoxyalkylene ether-based nonionic surfactants include polyoxyalkylene alkyl ethers, polyoxyalkylene alkylphenyl ethers, polyoxyalkylene polyol alkyl ethers, and polyoxyalkylene mono, di, or tristyrylphenyl ethers. Among these, polyoxyalkylene alkylphenyl ethers are preferably used. The polyol is preferably a polyhydric alcohol having 2 to 12 carbon atoms, such as ethylene glycol, propylene glycol, glycerin, sorbitol, glucose, sucrose, pentaerythritol, and sorbitan.

[0100] Examples of the polyoxyalkylene ester-based nonionic surfactants include polyoxyalkylene fatty acid esters and polyoxyalkylene alkylrosin acid esters. Examples of the polyhydric alcohol fatty acid ester-based nonionic surfactants include fatty acid esters of polyhydric alcohols having 2 to 12 carbon atoms or fatty acid esters of polyoxyalkylene polyhydric alcohols. More specifically, examples include sorbitol fatty acid esters, sorbitan fatty acid esters, glycerin fatty acid esters, polyglycerin fatty acid esters, and pentaerythritol fatty acid esters. Polyalkylene oxide adducts of these (e.g., polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene glycerin fatty acid esters, etc.) can also be used. Among these, sorbitan fatty acid esters are preferred. Examples of sugar fatty acid ester-based nonionic surfactants include fatty acid esters of sucrose, glucose, maltose, fructose, and polysaccharides, and polyalkylene oxide adducts of these can also be used. Examples of alkyl polyglycoside-based nonionic surfactants include glucose, maltose, fructose, and sucrose as glycosides, and for example, alkyl glucosides, alkyl polyglucosides, polyoxyalkylene alkyl glucosides, and polyoxyalkylene alkyl polyglucosides, as well as their fatty acid esters. Furthermore, all of these polyalkylene oxide adducts can also be used.

[0101] Examples of alkyl groups in these nonionic surfactants include linear or branched saturated or unsaturated alkyl groups having 4 to 30 carbon atoms. Examples of polyoxyalkylene groups include those having alkylene groups having 2 to 4 carbon atoms, for example, those with an addition number of ethylene oxide moles of about 1 to 50 moles. Examples of the fatty acids include linear or branched saturated or unsaturated fatty acids having 4 to 30 carbon atoms.

[0102] Polyoxyethylene (10) octylphenyl ether (Tritoon® X-100) and sorbitan monolaurate (Span 20) are particularly preferred as the nonionic surfactant.

[0103] Examples of the aforementioned amphoteric surfactants include quaternary ammonium base / sulfonic acid group (-SO ３ Examples of amphoteric surfactants include H-type, quaternary ammonium base / phosphate group type (water soluble), quaternary ammonium base / phosphate group type (water insoluble), and quaternary ammonium base / carboxyl group type. The acid group may be a salt. In particular, it is preferable that the amphoteric surfactant has both positive and negative charges in one molecule, and that the acid dissociation constant (pKa) of the acid group is preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less.

[0104] The amphoteric surfactants mentioned above include, specifically, 3-[(3-collamidopropyl)dimethylamino]-2-hydroxy-1-propanesulfonic acid (CHAPSO), 3-[(3-collamidopropyl)dimethylamino]-propanesulfonic acid (CHAPS), N,N-bis(3-D-gluconamidopropyl)-collamide, n-octadecyl-N,N'-dimethyl-3-amino-1-propanesulfonic acid, n-decyl-N,N'-dimethyl-3-amino-1-propanesulfonic acid, n-dodecyl-N,N'-dimethyl-3-amino-1-propanesulfonic acid, and n-tetradecyl-N,N'-dimethyl-3-amino-1-propanesulfonic acid {Zwittergent(trademark)-3-14}. Examples include ammonium sulfobetaines such as n-hexadecyl-N,N'-dimethyl-3-amino-1-propanesulfonic acid and n-octadecyl-N,N'-dimethyl-3-amino-1-propanesulfonic acid, phosphocholines such as n-octylphosphocholine, n-nonylphosphocholine, n-decylphosphocholine, n-dodecylphosphocholine, n-tetradecylphosphocholine, and n-hexadecylphosphocholine, and phosphatidylcholines such as dilauroylphosphatidylcholine, dimyristoylphosphatidylcholine, dipalmitoylphosphatidylcholine, distearoylphosphatidylcholine, dioleoylphosphatidylcholine, and dilinoleoylphosphatidylcholine. Among these, 3-[(3-coramidopropyl)dimethylamino]-propanesulfonic acid (CHAPS) is particularly preferred because it can remove proteins appropriately while stabilizing the rubber particle membrane.

[0105] The treatment concentration (usage concentration) of the surfactant is preferably within three times the critical micelle concentration (CMC) of the surfactant used. More preferably within 2.5 times, and even more preferably within 2.0 times. The lower limit is preferably 0.05 times or more, more preferably 0.1 times or more, and even more preferably 0.3 times or more.

[0106] The above manufacturing method preferably includes a step of preparing a substrate represented by formula (5). The substrate represented by formula (5) can be obtained by denaturing (adding an alkyne moiety to) an initiating substrate such as dimethylallyl diphosphate (DMAPP), geranyl diphosphate (GPP), farnesyl diphosphate (FPP), geranylgeranyl diphosphate (GGPP), or geranylfarnesyl diphosphate (GFPP).

[0107] The above manufacturing method preferably includes a step of preparing prenyltransferase. The step of preparing prenyltransferase may involve, for example, preparing a culture of the organism or purified enzyme as described above, or isolating it from natural rubber latex. The organism may be a transformed organism (transformed organism) that has been produced by genetic engineering techniques to express a mutant enzyme.

[0108] The above manufacturing method preferably includes a step to stop the reaction between the substrate represented by formula (5) and the compound represented by formula (6). An example of a step to stop the reaction is the addition of saturated saline solution.

[0109] The above manufacturing method may include a step of recovering a polyisoprenoid from the reaction product of a substrate represented by formula (5) and a compound represented by formula (6). A conventionally known purification method, such as centrifugation, can be used as appropriate for the polyisoprenoid recovery step.

[0110] (Rubber Composition) The present invention is also a rubber composition containing the above-mentioned polyisoprenoid. The amount of the above-mentioned polyisoprenoid is preferably 1 part by mass or more, more preferably 20 parts by mass or more, even more preferably 40 parts by mass or more, and particularly preferably 60 parts by mass or more, and may be 100 parts by mass, per 100 parts by mass of the rubber component.

[0111] The above rubber composition contains a rubber component. The above polyisoprenoid can be used as all or part of the rubber component. Here, the rubber component generally has a weight-average molecular weight (Mw) of 10,000 or more.

[0112] The weight-average molecular weight of the rubber component is preferably 50,000 or more, more preferably 150,000 or more, even more preferably 200,000 or more, and also preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,000,000 or less. Within this range, a better effect tends to be obtained.

[0113] In this specification, the weight-average molecular weight (Mw) can be determined by the method described above.

[0114] The above rubber composition preferably contains an isoprene-based rubber with high compatibility with the above polyisoprenoid as a rubber component. Examples of isoprene-based rubbers include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR. For NR, for example, SIR20, RSS#3, TSR20, etc., which are common in the tire industry can be used. For IR, there are no particular limitations, and for example, IR2200, etc., which are common in the tire industry can be used. Examples of modified NR include deproteinized natural rubber (DPNR) and high-purity natural rubber, for modified NR include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber, and for modified IR, epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These may be used alone or in combination of two or more. Among these, NR is preferred.

[0115] When the above rubber composition contains isoprene-based rubber, the content of isoprene-based rubber in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and also preferably 55% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less. When the content is within the above range, the effect tends to be better obtained.

[0116] The above rubber composition may contain styrene-butadiene rubber (SBR) as a rubber component. The SBR is not particularly limited, and for example, emulsion-polymerized styrene-butadiene rubber (E-SBR), solution-polymerized styrene-butadiene rubber (S-SBR), etc., can be used. Commercial products include those from Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, and Nippon Zeon Co., Ltd. As for the SBR, one type may be used alone, or two or more types may be used in combination, but the use of two or more types in combination is preferable.

[0117] The styrene content of SBR is preferably 5% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and also preferably 45% by mass or less, more preferably 35% by mass or less, and even more preferably 25% by mass or less. When the content is within the above range, the effect tends to be better obtained.

[0118] The vinyl content of SBR is preferably 5% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and also preferably 65% ​​by mass or less, more preferably 45% by mass or less, and even more preferably 30% by mass or less. When the content is within the above range, the effect tends to be better.

[0119] The styrene content of the SBR mentioned above refers to the styrene content of a single SBR if there is only one type of SBR, and to the average styrene content if there are multiple types. The average styrene content of an SBR can be calculated as {Σ (content of each SBR × styrene content of each SBR)} / total content of all SBRs. For example, if 85% of the SBRs have a styrene content of 40% by mass and 5% of the SBRs have a styrene content of 25% by mass out of 100% by mass of rubber components, the average styrene content of the SBRs is 39.2% by mass (= (85 × 40 + 5 × 25) / (85 + 5)).

[0120] Furthermore, the vinyl content of the above-mentioned SBR is the ratio of vinyl bonds when the total mass of the butadiene portion in the SBR is set to 100 (unit: mass%), and is calculated as: vinyl content [mass%] + cis content [mass%] + trans content [mass%] = 100 [mass%]. If there is one type of SBR, it means the vinyl content of that SBR, and if there are multiple types, it means the average vinyl content. The average vinyl content of an SBR can be calculated as Σ{content of each SBR × (100 [mass%] - styrene content of each SBR [mass%]) × vinyl content of each SBR [mass%]} / Σ{content of each SBR × (100 [mass%] - styrene content of each SBR [mass%])}, for example, in 100 parts by mass of rubber component, 75 parts by mass of SBR have a styrene content of 40 mass%, a vinyl content of 30 mass%, and 25 mass of styrene content, Vinyl content: If 15 parts by mass are 20% by mass SBR and the remaining 10 parts by mass are other than SBR, the average vinyl content of SBR is 28% by mass (= {75 × (100 [mass%] - 40 [mass%]) × 30 [mass%] + 15 × (100 [mass%] - 25 [mass%]) × 20 [mass%])} / {75 × (100 [mass%] - 40 [mass%]) + 15 × (100 [mass%] - 25 [mass%])}.

[0121] The glass transition temperature (Tg) of SBR is preferably -20°C or lower, more preferably -30°C or lower, and also preferably -80°C or higher, more preferably -65°C or higher. Within this range, better effects tend to be obtained. The glass transition temperature of SBR was measured in accordance with JIS-K7121 using a differential scanning calorimeter (Q200) manufactured by T.A. Instruments Japan, under a heating rate of 10°C / min.

[0122] Hydrogenated SBR, which has hydrogen added to it, can also be used as SBR. When SBR is hydrogenated SBR, there are no particular limitations on the method of hydrogenation or reaction conditions; hydrogenation may be carried out by known methods and under known conditions. Typically, this is carried out at 20 to 150°C, under a hydrogen pressure of 0.1 to 10 MPa, and in the presence of a hydrogenation catalyst. Other manufacturing methods and conditions are also not particularly limited; for example, the contents described in International Publication No. 2016 / 039005 can be applied. Note that hydrogenated SBR has the same structure as a copolymer of ethylene, butadiene, and styrene as a result of hydrogen being added to the butadiene portion of SBR. Therefore, in this specification, hydrogenated SBR includes not only hydrogenated butadiene-styrene copolymers (SBRs) but also copolymers of ethylene, butadiene, and styrene.

[0123] The hydrogenation rate of hydrogenated SBR is preferably 65 mol% or more, more preferably 70 mol% or more, even more preferably 75 mol% or more, with the total butadiene units before hydrogenation being 100 mol%, and also preferably 99 mol% or less, more preferably 97 mol% or less, and even more preferably 95 mol% or less. Within the above range, better effects tend to be obtained. Note that the hydrogenation rate is １ It can be calculated from the spectral reduction rate of the unsaturated bond region of the spectrum obtained by measuring 1H-NMR.

[0124] SBR may be oil-stretched rubber, resin-stretched rubber, or other plasticizer-stretched rubber. These may be used individually or in combination of two or more. Among these, resin-stretched rubber (resin-stretched SBR) is preferred. The amount of plasticizer in these stretchable rubbers is not particularly limited, but is usually about 5 to 50 parts by mass per 100 parts by mass of rubber solids. The oil used in oil-stretched rubber and the resin used in resin-stretched rubber are the same as those described later. Other plasticizers include liquid polymers, which will be described later.

[0125] SBR may be modified to introduce functional groups that interact with fillers such as silica. Examples of such functional groups include silicon-containing groups (-SiR ３(R may be the same or different, and may be hydrogen, hydroxyl group, hydrocarbon group, alkoxy group, etc.), amino group, amide group, isocyanate group, imino group, imidazole group, urea group, ether group, carbonyl group, oxycarbonyl group, mercapto group, sulfide group, disulfide group, sulfonyl group, sulfinyl group, thiocarbonyl group, ammonium group, imide group, hydrazo group, azo group, diazo group, carboxyl group, nitrile group, pyridyl group, alkoxy group, hydroxyl group, oxy group, epoxy group, etc. These functional groups may have substituents. Among these, silicon-containing groups are preferred, -SiR ３ (R is the same or different, and is hydrogen, a hydroxyl group, a hydrocarbon group (preferably a hydrocarbon group having 1 to 6 carbon atoms (more preferably an alkyl group having 1 to 6 carbon atoms)), or an alkoxy group (preferably an alkoxy group having 1 to 6 carbon atoms)), and it is more preferable that at least one of R is a hydroxyl group.

[0126] Specific examples of compounds (modifiers) that introduce the above functional groups include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, and 3-diethylaminopropyltriethoxysilane.

[0127] When the above rubber composition contains SBR, the SBR content in 100% by mass of the rubber component is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, and also preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less. When the content is within the above range, the effect tends to be better obtained.

[0128] The above rubber composition may contain butadiene rubber (BR) as a rubber component. The BR is not particularly limited, and common types used in the tire industry can be used, such as BR1220 from Nippon Zeon Co., Ltd., BR150B from Ube Industries, Ltd., BR1280 from LG Chem, BR containing 1,2-syndiotactic polybutadiene crystals (SPB) such as VCR412 and VCR617 from Ube Industries, Ltd., and butadiene rubber synthesized using rare earth element catalysts (rare earth BR). These may be used individually or in combination of two or more. Among these, rare earth BR is preferred.

[0129] While known rare earth element catalysts can be used in the synthesis of rare earth BRs, lanthanum series rare earth element compounds are preferred, and neodymium-containing compounds (Nd-based catalysts) are more preferred.

[0130] BR may be oil-stretched rubber, resin-stretched rubber, or other plasticizer-stretched rubber. These may be used individually or in combination of two or more. The amount of plasticizer in these stretchable rubbers is not particularly limited, but is usually about 5 to 50 parts by mass per 100 parts by mass of rubber solids. The oil used in oil-stretched rubber and the resin used in resin-stretched rubber are the same as those described later. Other plasticizers include liquid polymers, which will be described later.

[0131] BR may be modified to introduce functional groups that interact with fillers such as silica. Examples of such functional groups include silicon-containing groups (-SiR ３(R may be the same or different, and may be hydrogen, hydroxyl group, hydrocarbon group, alkoxy group, etc.), amino group, amide group, isocyanate group, imino group, imidazole group, urea group, ether group, carbonyl group, oxycarbonyl group, mercapto group, sulfide group, disulfide group, sulfonyl group, sulfinyl group, thiocarbonyl group, ammonium group, imide group, hydrazo group, azo group, diazo group, carboxyl group, nitrile group, pyridyl group, alkoxy group, hydroxyl group, oxy group, epoxy group, etc. These functional groups may have substituents. Among these, silicon-containing groups are preferred, -SiR ３ (R is the same or different, and is hydrogen, a hydroxyl group, a hydrocarbon group (preferably a hydrocarbon group having 1 to 6 carbon atoms (more preferably an alkyl group having 1 to 6 carbon atoms)), or an alkoxy group (preferably an alkoxy group having 1 to 6 carbon atoms)), and it is more preferable that at least one of R is a hydroxyl group.

[0132] Specific examples of compounds (modifiers) that introduce the above functional groups include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, and 3-diethylaminopropyltriethoxysilane.

[0133] Hydrogenated BR, which has hydrogen added to it, can also be used as BR. When BR is hydrogenated BR, there are no particular limitations on the method of hydrogenation or reaction conditions; hydrogenation may be carried out by known methods and under known conditions. Typically, this is carried out at 20 to 150°C, under a hydrogen pressure of 0.1 to 10 MPa, and in the presence of a hydrogenation catalyst. Other manufacturing methods and conditions are also not particularly limited; for example, the contents described in International Publication No. 2016 / 039005 can be applied. Note that hydrogenated BR has the same structure as an ethylene-butadiene copolymer as a result of hydrogen being added to the butadiene portion of BR. Therefore, in this specification, hydrogenated BR includes not only hydrogenated BR but also an ethylene-butadiene copolymer.

[0134] The hydrogenation rate of hydrogenated BR is preferably 65 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, with the total butadiene units before hydrogenation being 100 mol%, and also preferably 95 mol% or less, more preferably 92 mol% or less, and even more preferably 90 mol% or less. Within the above range, a better effect tends to be obtained. Note that the hydrogenation rate is １ It can be calculated from the spectral reduction rate of the unsaturated bond region of the spectrum obtained by measuring 1H-NMR.

[0135] The cis content of BR is preferably 10% by mass or more, more preferably 50% by mass or more, even more preferably 90% by mass or more, and also preferably 99.9% by mass or less, more preferably 99% by mass or less, and even more preferably 97% by mass or less. When it is within the above range, the effect tends to be better obtained. The cis content of BR can be measured by infrared absorption spectroscopy.

[0136] The above-mentioned cis content of BR refers to the cis content of a single type of BR if there is only one type, and the average cis content if there are multiple types. The average cis content of BR can be calculated as {Σ (content of each BR × cis content of each BR)} / total content of all BRs. For example, if 20% of the rubber component is 90% cis and 10% is 40% cis, the average cis content of BR is 73.3% (= (20 × 90 + 10 × 40) / (20 + 10)).

[0137] When the above rubber composition contains BR, the BR content in 100% by mass of the rubber component is preferably 2% by mass or more, more preferably 6% by mass or more, even more preferably 10% by mass or more, and also preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0138] Other rubber components besides isoprene-based rubber, BR, and SBR include diene-based rubbers such as acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), and styrene-isoprene-butadiene copolymer rubber (SIBR). These may be used individually or in combination of two or more types.

[0139] The rubber components other than isoprene-based rubber, BR, and SBR may be oil-stretched rubber, resin-stretched rubber, or other plasticizer-stretched rubber. These may be used individually or in combination of two or more. The amount of plasticizer in these stretched rubbers is not particularly limited, but is usually about 5 to 50 parts by mass per 100 parts by mass of rubber solids. The oil used in oil-stretched rubber and the resin used in resin-stretched rubber are the same as those described later. Other plasticizers include liquid polymers, which will be described later.

[0140] Rubber components other than isoprene-based rubber, BR, and SBR may be modified to introduce functional groups that interact with fillers such as silica. Examples of such functional groups include silicon-containing groups (-SiR ３ (R may be the same or different, and may be hydrogen, hydroxyl group, hydrocarbon group, alkoxy group, etc.), amino group, amide group, isocyanate group, imino group, imidazole group, urea group, ether group, carbonyl group, oxycarbonyl group, mercapto group, sulfide group, disulfide group, sulfonyl group, sulfinyl group, thiocarbonyl group, ammonium group, imide group, hydrazo group, azo group, diazo group, carboxyl group, nitrile group, pyridyl group, alkoxy group, hydroxyl group, oxy group, epoxy group, etc. These functional groups may have substituents. Among these, silicon-containing groups are preferred, -SiR ３ (R is the same or different, and is hydrogen, a hydroxyl group, a hydrocarbon group (preferably a hydrocarbon group having 1 to 6 carbon atoms (more preferably an alkyl group having 1 to 6 carbon atoms)), or an alkoxy group (preferably an alkoxy group having 1 to 6 carbon atoms)), and it is more preferable that at least one of R is a hydroxyl group.

[0141] Specific examples of compounds (modifiers) that introduce the above functional groups include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, and 3-diethylaminopropyltriethoxysilane.

[0142] The raw materials (monomers) for synthetic rubbers such as isoprene rubber, SBR, and BR may be derived from underground resources such as petroleum and natural gas, or they may be recycled from rubber products such as tires or non-rubber products such as polystyrene. The monomers obtained by recycling (recycled monomers) are not particularly limited, but include recycled polyisoprene, recycled butadiene, and recycled aromatic vinyl. Examples of butadiene include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl include styrene. In particular, it is preferable to use recycled polyisoprene (recycled isoprene), recycled butadiene (recycled butadiene), and / or recycled styrene (recycled styrene) as raw materials.

[0143] The method for producing recycled monomer is not particularly limited, and for example, it can be synthesized from recycled naphtha obtained by decomposing rubber products such as tires. Furthermore, the method for producing recycled naphtha is not particularly limited, and for example, rubber products such as tires may be decomposed under high temperature and pressure, decomposed by microwaves, or extracted after mechanical grinding.

[0144] Furthermore, the raw materials (monomers) for synthetic rubbers such as isoprene rubber, SBR, and BR may be derived from biomass. In this specification, biomass refers to substances derived from natural resources such as plants. Biomass is not particularly limited, but examples include agricultural, forestry, and fishery products, sugars, wood chips, plant residues after obtaining useful components, plant-derived ethanol, and biomass naphtha.

[0145] The biomass-derived monomer (biomass monomer) is not particularly limited and includes biomass-derived butadiene and biomass-derived aromatic vinyl. The butadiene is 1,2-butadiene and 1,3-butadiene. The aromatic vinyl is not particularly limited and includes styrene. Furthermore, the method for producing the biomass monomer is not particularly limited and includes, for example, biological and / or chemical and / or physical conversion of plants and animals. A typical example of biological conversion is fermentation by microorganisms, while examples of chemical and / or physical conversion include catalytic conversion, high heat conversion, high pressure conversion, electromagnetic wave conversion, critical liquid conversion, and combinations thereof.

[0146] The polymer synthesized from biomass monomer components (biomass polymer) is not particularly limited, and examples include polybutadiene rubber synthesized from biomass-derived butadiene, and aromatic vinyl / butadiene copolymers synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyl. Examples of the aromatic vinyl / butadiene copolymer include styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene.

[0147] Whether the raw materials for a polymer are biomass-derived can be determined by measuring pMC (percent Modern Carbon) in accordance with ASTM D6866-10.

[0148] pMC stands for Modern Standard Reference. １４ Sample relative to C concentration １４ This is the ratio of C concentrations and is a value used as an indicator of the biomass ratio of a compound. The significance of this value is described below. 1 mole of carbon atoms (6.02 × 10⁻¹⁶) ２３ (Each) contains approximately 6.02 × 10¹⁶ atoms, which is about one trillionth of the amount of carbon atoms in a normal atom. １１ individual １４ C exists. １４C is called a radioactive isotope, and its half-life is 5,730 years, decreasing regularly. It takes 226,000 years for all of these to decay. Therefore, after carbon dioxide in the atmosphere and the like are taken up and fixed by plants and the like, in fossil fuels such as coal, oil, and natural gas where more than 226,000 years have passed, at the beginning of fixation, it was also included in these. １４ All of the C elements have decayed. Therefore, at present in the 21st century, fossil fuels such as coal, oil, and natural gas １４ do not contain any C elements at all. Therefore, chemical substances produced from these fossil fuels １４ also do not contain any C elements.

[0149] On the other hand, １４ C is constantly generated by cosmic rays undergoing nuclear reactions in the atmosphere, and it is balanced with the decrease due to radioactive decay. In the earth's atmospheric environment, １４ the amount of C is constant. Therefore, for substances derived from biomass resources that are circulating in the current environment, １４ the C concentration is about 1×10 －１２ mol% with respect to the entire C atoms as described above. Therefore, by utilizing the difference between these values, the biomass ratio of a certain compound can be calculated.

[0150] This １４ C is generally measured as follows. Using accelerator mass spectrometry based on a tandem accelerator, １３ C concentration ( １３ C / １２ C), １４ C concentration ( １４ C / １２ C) is measured. In the measurement, １４ as the modern standard reference for the concentration of C, the １４ C concentration in the circulating carbon in nature at the time of 1950 is adopted. As a specific standard substance, the oxalic acid standard provided by NIST (National Institute of Standards and Technology: National Institute of Standards and Technology, USA) is used. The specific activity of carbon in this oxalic acid ( １４The radioactivity intensity of C) is separated for each carbon isotope, １３ For C, it is corrected to a certain value, and the value after performing decay correction from 1950 AD to the measurement date is used as the standard １４ C concentration value (100%). The ratio of this value to the value of the actually measured sample becomes the pMC value.

[0151] Therefore, if the rubber is made of 100% biomass-derived substances, although there are regional differences, etc., currently in the normal state, it often does not reach 100, so it will show a value of approximately 110 pMC. On the other hand, for chemical substances derived from fossil fuels such as petroleum, when this １４ C concentration is measured, it will show a value of about 0 pMC (for example, 0.3 pMC). This value corresponds to the biomass ratio of 0% mentioned above.

[0152] From the above, using materials such as rubber with a high pMC value, that is, materials such as rubber with a high biomass ratio, in the rubber composition is suitable from the aspect of environmental protection.

[0153] The above rubber composition may contain a thermoplastic elastomer as an elastomer other than the rubber component. The thermoplastic elastomer is a copolymer (block copolymer) composed of a hard segment that plays the role of crosslinking points and a soft segment that exhibits rubber elasticity, and is usually solid at 25°C.

[0154] Examples of the hard segment include polystyrene, polypropylene, polyester, polyamide, polyvinyl chloride, polyurethane, etc., and examples of the soft segment include vinyl-polybutadiene, polyisoprene, polybutadiene, polyethylene, polychloroprene, poly 2,3-dimethylbutadiene, etc. These may be one kind or two or more kinds.

[0155] The thermoplastic elastomer may be used alone or in combination of two or more. As commercially available products, products of Kuraray Co., Ltd., Asahi Kasei Corporation, etc. can be used. In this specification, the thermoplastic elastomer is not included in the rubber component.

[0156] The thermoplastic elastomer is preferably a thermoplastic elastomer having a styrene block (styrene-based thermoplastic elastomer). Specific examples of styrene-based thermoplastic elastomers include styrene-vinylisoprene-styrene triblock copolymer (SIS), styrene-isobutylene diblock copolymer (SIB), styrene-butadiene-styrene triblock copolymer (SBS), styrene-ethylene-butylene-styrene triblock copolymer (SEBS), styrene-ethylene-propylene-styrene triblock copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene triblock copolymer (SEEPS), and styrene-butadiene-butylene-styrene triblock copolymer (SBBS). These may be used individually or in combination of two or more. Among these, styrene-ethylene-ethylene-propylene-styrene triblock copolymer (SEEPS) is more preferred.

[0157] The styrene content of the styrene-based thermoplastic elastomer is preferably 2% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and also preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less. Within the above range, a better effect tends to be obtained.

[0158] When the above rubber composition contains a thermoplastic elastomer, the content of the thermoplastic elastomer is preferably 1 to 40 parts by mass per 100 parts by mass of the rubber component. Within this range, a better effect tends to be obtained.

[0159] The above rubber composition preferably contains a filler. For example, the above rubber composition more preferably contains silica as a filler. When the above rubber composition is a rubber composition for tires, the silica is not particularly limited, and common types used in the tire industry can be used, such as silica prepared by a dry process (anhydrous silica) or silica prepared by a wet process (hydrated silica). The raw material for silica is not particularly limited, and may be a mineral-derived raw material such as quartz, or a biological-derived raw material such as rice husks (for example, silica made from biomass materials such as rice husks), or silica recycled from silica-containing products may be used. Among these, hydrated silica prepared by a wet process is preferred because it has a high silanol group content. These silicas may be used individually or in combination of two or more, but it is preferable to use two or more in combination. Commercial products from EVONIK, Tosoh Silica Co., Ltd., Solvay Japan Ltd., Tokuyama Corporation, etc. can be used.

[0160] Silica derived from biomass materials can be obtained, for example, by extracting silicates from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and then using these silicates to react with sulfuric acid in the same way as conventional wet silica, the precipitate of silicon dioxide is filtered, washed with water, dried, and pulverized.

[0161] The silica recycled from silica-containing products can be, for example, silica recovered from products containing silica such as semiconductors and other electronic components, tires, desiccants, and diatomaceous earth and other filter materials. The recovery method is not particularly limited and can include thermal decomposition and decomposition by electromagnetic waves. Among these, silica recovered from semiconductors and other electronic components or tires is preferred.

[0162] When silica crystallizes, it becomes insoluble in water, and its component, silicic acid, cannot be utilized. By controlling the combustion temperature and combustion time, the crystallization of silica in rice husk ash can be suppressed (see Japanese Patent Publication No. 2009-2594, Akita Prefectural University Web Journal B / 2019, vol. 6, pp. 216-222, etc.).

[0163] Amorphous silica extracted from rice husks can be commercially available from companies such as Wilmar.

[0164] The average particle size of silica is preferably 24 nm or less, more preferably 19 nm or less, even more preferably 18 nm or less, and also preferably 6 nm or more, more preferably 9 nm or more, and even more preferably 12 nm or more. Within the above range, a better effect tends to be obtained.

[0165] In this specification, the method for measuring the average particle size of silica is to use transmission electron microscopy (TEM) observation. Specifically, silica particles are photographed with a transmission electron microscope, and if the particle shape is spherical, the diameter of the sphere is defined as the particle size; if it is needle-shaped or rod-shaped, the shorter axis is defined as the particle size; if it is irregularly shaped, the average particle size from the center is defined as the particle size; and the average value of the particle sizes of 100 fine particles is defined as the average particle size.

[0166] When the above rubber composition contains silica, the silica content is preferably 65 parts by mass or more, more preferably 75 parts by mass or more, even more preferably 85 parts by mass or more, and even more preferably more than 125 parts by mass, per 100 parts by mass of the rubber component, and also preferably 185 parts by mass or less, more preferably 165 parts by mass or less, and even more preferably 145 parts by mass or less. When the silica content is within the above range, a better effect tends to be obtained.

[0167] Other fillers besides silica include carbon black, vulcanized rubber particles, aluminum hydroxide, talc, calcium compounds, and short fibers. These may be used individually or in combination of two or more. Among these, vulcanized rubber particles are preferred.

[0168] Vulcanized rubber particles are particles made of vulcanized rubber, and specifically, rubber powder as defined in JIS K 6316:2017 can be used. From the viewpoint of environmental considerations and cost, recycled rubber powder produced from crushed waste tires is preferred. These may be used individually or in combination of two or more types. The vulcanized rubber particles are not particularly limited and may be either unmodified vulcanized rubber particles or modified vulcanized rubber particles.

[0169] Commercially available vulcanized rubber particles can be those from companies such as Lehigh and Muraoka Rubber Industries Co., Ltd. Note that, in this specification, vulcanized rubber particles are not included in the rubber component.

[0170] The average particle size of the vulcanized rubber particles is preferably 50 μm or more, more preferably 100 μm or more, even more preferably 200 μm or more, and also preferably 1000 μm or less, more preferably 900 μm or less, and even more preferably 800 μm or less. The average particle size of the vulcanized rubber particles is the average particle size on a mass basis calculated from the particle size distribution measured in accordance with JIS Z 8815:1994.

[0171] When the above rubber composition contains vulcanized rubber particles, the content of vulcanized rubber particles is preferably 2 parts by mass or more, more preferably 6 parts by mass or more, even more preferably 10 parts by mass or more, and preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, a better effect tends to be obtained.

[0172] The carbon black is not particularly limited and examples include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. The raw material for carbon black may be biomass material such as lignin and vegetable oil, or it may be pyrolysis oil obtained by thermal decomposition of waste tires. The method of producing carbon black may be by combustion such as the furnace method, by hydrothermal carbonization (HTC), or by thermal decomposition of methane such as the thermal black method. Commercial products that can be used include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., and Columbia Carbon Corporation. These may be used individually or in combination of two or more types.

[0173] The specific surface area of ​​cetyltrimethylammonium bromide (CTAB) in carbon black is preferably 70 m². ２ / g or more, more preferably 100m ２ / g or more, more preferably 130m２ / g or more, particularly preferably 160m ２ It is 1 / g or more, and preferably 230m ２ / g or less, more preferably 210m ２ / g or less, more preferably 190m ２ It is less than or equal to / g. The CTAB specific surface area of ​​carbon black is measured according to JIS K6217-3:2001.

[0174] When the above rubber composition contains carbon black, the carbon black content is preferably 2 parts by mass or more, more preferably 6 parts by mass or more, even more preferably 10 parts by mass or more, and preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, a better effect tends to be obtained.

[0175] In this specification, aluminum hydroxide is defined as Al(OH) ３ or Al ２ O ３ 3H ２ It means O. Commercially available products include those from Sumitomo Chemical Co., Ltd., Showa Denko K.K., Nabaltec, etc. These can be used individually or in combination of two or more types.

[0176] The average particle diameter of aluminum hydroxide is preferably 0.1 μm or more, more preferably 0.5 μm or more, even more preferably 0.8 μm or more, and also preferably 5 μm or less, more preferably 3 μm or less, and even more preferably 1 μm or less. When the particle diameter is within the above range, the effect tends to be better. In this specification, the method for measuring the average particle diameter of aluminum hydroxide is transmission electron microscopy (TEM) observation. Specifically, aluminum hydroxide particles are photographed with a transmission electron microscope, and if the particle shape is spherical, the diameter of the sphere is taken as the particle diameter; if it is needle-shaped or rod-shaped, the short axis is taken as the particle diameter; if it is irregularly shaped, the average particle diameter from the center is taken as the particle diameter; and the average value of the particle sizes of 100 fine particles is taken as the average particle diameter.

[0177] BET specific surface area of ​​aluminum hydroxide (nitrogen adsorption specific surface area, N ２SA) is preferably 5m ２ / g or more, more preferably 8m ２ / g or more, more preferably 10m ２ It is 1 / g or more, and preferably 40m ２ / g or less, more preferably 30m ２ / g or less, more preferably 20m ２ It is less than or equal to / g. The BET specific surface area of ​​aluminum hydroxide is a value measured by the BET method in accordance with ASTM D3037-81.

[0178] If the above rubber composition contains aluminum hydroxide, the amount of aluminum hydroxide is preferably 1 to 30 parts by mass per 100 parts by mass of the rubber component.

[0179] The average particle size of talc is preferably 50 μm or less, more preferably 30 μm or less. The lower limit of the average particle size of talc is not particularly limited, but is preferably 1 μm or more.

[0180] If the above rubber composition contains talc, the talc content is preferably 1 to 50 parts by mass per 100 parts by mass of the rubber component.

[0181] Calcium compounds are compounds containing calcium, such as inorganic salts of calcium oxide, calcium hydroxide, and calcium carbide; and oxo salts of calcium carbonate, calcium nitrate, and calcium sulfate. Eggshells (main component: calcium carbonate) are another example of materials containing calcium compounds. These may be used individually or in combination of two or more. Oxo salts are preferred, and calcium carbonate is more preferred. In this specification, calcium fatty acid salts are treated as processing aids described later and are not included in the fillers.

[0182] If the above rubber composition contains a calcium compound, the amount of the calcium compound is preferably 1 to 30 parts by mass per 100 parts by mass of the rubber component.

[0183] Examples of short fibers that can be used include organic short fibers and inorganic short fibers. Specific examples of organic short fibers include nanocellulose such as cellulose nanofibers (CNF) and cellulose nanocrystals (CNC); biomass nanomaterials such as chitin nanofibers and chitosan nanofibers; and specific examples of inorganic short fibers include metal fibers and glass fiber systems. Commercially available products include those from Nippon Paper Industries Co., Ltd. and Sugino Machine Co., Ltd. These may be used individually or in mixtures of two or more. Among these, organic short fibers are preferred, and nanocellulose is more preferred.

[0184] The particle size of the nanocellulose is preferably 10 nm or larger, more preferably 20 nm or larger, even more preferably 25 nm or larger, and particularly preferably 28 nm or larger. It is also preferably 50 nm or smaller, more preferably 40 nm or smaller, even more preferably 35 nm or smaller, and particularly preferably 32 nm or smaller. When the particle size is within the above range, a better effect tends to be obtained.

[0185] The particle size of nanocellulose is the average fiber diameter measured by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray scattering data analysis, and pore electrical resistance method (Culter principle method). In this specification, the average fiber diameter of nanocellulose (cellulose fiber) is typically the average fiber diameter of an aggregate of cellulose fibers formed by the aggregation of cellulose molecules.

[0186] If the above rubber composition contains short fibers, the amount of short fibers is preferably 1 to 40 parts by mass per 100 parts by mass of the rubber component.

[0187] When the above rubber composition contains a filler, the filler content is preferably 95 parts by mass or more, more preferably 115 parts by mass or more, even more preferably 135 parts by mass or more, and preferably 190 parts by mass or less, more preferably 165 parts by mass or less, and even more preferably 145 parts by mass or less, based on 100 parts by mass of the rubber component. When the content is within the above range, a better effect tends to be obtained.

[0188] The above rubber composition may contain a plasticizer. A plasticizer is a material that imparts plasticity to the rubber component, and the concept includes both liquid plasticizers at 25°C and solid plasticizers at 25°C. Examples of plasticizers include resins, oils, liquid polymers, and ester-based plasticizers. Among these, resins and liquid polymers are preferred. These plasticizers may be derived from mineral resources such as petroleum and natural gas, from biomass, or from naphtha recycled from rubber or non-rubber products. In addition, low molecular weight hydrocarbon components obtained by thermal decomposition and extraction of used tires or products containing various components may be used as plasticizers. These plasticizers may be used individually or in combination of two or more.

[0189] The resin is not particularly limited, but resins commonly used in the tire industry can be used. Examples include adhesive resins such as C5 resins, C9 resins, C5C9 resins, aromatic vinyl resins, cyclopentadiene resins, coumarone resins, indene resins, terpene resins, rosin resins, and phenolic resins. Among these, dicyclopentadiene resins are preferred. These resins may be used individually or in combination of two or more, but it is preferable to use two or more in combination. In this specification, the resin may be solid or liquid at 25°C.

[0190] C5 resins refer to resins obtained by polymerizing C5 fractions, and may be hydrogenated or modified versions of these resins. Examples of C5 fractions include petroleum fractions with 4 to 5 carbon atoms, such as cyclopentadiene, isoprene, pentane, isopentane, neopentane, pentene, and pentadiene. These C5 resins may be used individually or in combination of two or more types.

[0191] C9 resins refer to resins obtained by polymerizing a C9 fraction, and may be obtained by polymerizing a C9 fraction alone, or as copolymers obtained by copolymerizing a C9 fraction with other components. They may also be hydrogenated or modified. Examples of C9 fractions include petroleum fractions with 8 to 10 carbon atoms, such as vinyltoluene, alkylstyrene, coumarone, indene, and methylindene. These C9 resins may be used individually or in combination of two or more types.

[0192] C5C9 resins refer to resins obtained by copolymerizing the C5 fraction and the C9 fraction, and may be hydrogenated or modified. As C5C9 petroleum resins, for example, those commercially available from Tosoh Corporation, LUHUA Corporation, etc., can be used. These C5C9 resins may be used individually or in combination of two or more types.

[0193] Aromatic vinyl resins refer to resins containing aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, and p-chlorostyrene as the most abundant monomer component, and may also be hydrogenated or modified versions of these compounds. For aromatic vinyl resins, α-methylstyrene or a homopolymer of styrene, or a copolymer of α-methylstyrene and styrene is preferred, and a copolymer of α-methylstyrene and styrene is more preferred, due to their economical nature, ease of processing, and excellent heat generation properties. As aromatic vinyl resins, commercially available products from companies such as Kraton, Eastman Chemical Company, and Mitsui Chemicals, Inc. can be used. These aromatic vinyl resins may be used individually or in combination of two or more types.

[0194] Dicyclopentadiene resins refer to resins containing cyclopentadiene (CPD) or dicyclopentadiene (DCPD) as monomer components, and these may be hydrogenated or modified. Preferred dicyclopentadiene resins are DCPD / C9 resins containing dicyclopentadiene and a C9 fraction as monomer components (these DCPD / C9 resins may be hydrogenated or modified). Among these, DCPD / C9 resins containing dicyclopentadiene and styrene as monomer components are preferred, and DCPD / C9 resins containing dicyclopentadiene, styrene, and indene as monomer components are particularly preferred. Dicyclopentadiene resins that are commercially available from companies such as ExxonMobil, ENEOS Corporation, Nippon Zeon Corporation, and Maruzen Petrochemical Co., Ltd. can be used. These dicyclopentadiene resins may be used individually or in combination of two or more types.

[0195] Coumarone-based resins refer to resins containing coumarone as a monomer component, and may be hydrogenated or modified resins. Examples of coumarone resins include coumarone-indene resins containing coumarone and indene as monomer components, and coumarone-indene-styrene resins containing coumarone, indene, and styrene as monomer components. These coumarone-based resins may be used individually or in combination of two or more types.

[0196] Indene resins refer to resins that contain indene as a monomer component, and may be hydrogenated or modified resins. Examples of indene resins include coumarone-indene resins, which contain coumarone and indene as monomer components, and coumarone-indene-styrene resins, which contain coumarone, indene, and styrene as monomer components. These indene resins may be used individually or in combination of two or more types.

[0197] Terpene resins are resins that contain terpene compounds such as α-pinene, β-pinene, limonene, and dipentene as the most abundant monomer component, and may be hydrogenated or modified versions of these compounds. Specific examples of terpene resins include, for example, polyterpene resins containing only one or more of the aforementioned terpene compounds as monomer components; aromatically modified terpene resins containing the aforementioned terpene compounds and aromatic compounds as monomer components; and terpene-phenol resins containing the aforementioned terpene compounds and phenolic compounds as monomer components. Examples of aromatic compounds that serve as monomer components in aromatically modified terpene resins include styrene, α-methylstyrene, vinyltoluene, and divinyltoluene. Examples of phenolic compounds that serve as monomer components in terpene-phenol resins include phenol, bisphenol A, cresol, and xylenol. These terpene resins may be used individually or in combination of two or more types.

[0198] Rosin-based resins refer to resins containing rosin acid compounds such as abietic acid, neoabietic acid, palastic acid, and isopimal acid, and may be hydrogenated or modified versions of these compounds. Rosin-based resins are not particularly limited, but examples include natural resin rosin and rosin-modified resins obtained by hydrogenation, disproportionation, dimerization, esterification, etc. These rosin-based resins may be used individually or in combination of two or more types.

[0199] Phenolic resins refer to resins that contain phenol compounds such as phenol and cresol as the most abundant monomer component. Phenolic resins are not particularly limited, but examples include phenol-formaldehyde resins, alkylphenol-formaldehyde resins, alkylphenol-acetylene resins, and oil-modified phenol-formaldehyde resins. These phenolic resins may be used individually or in combination of two or more types.

[0200] The resin is preferably a modified resin (functionalized resin) into which functional groups have been introduced. Modified resins can be produced by known methods, for example, by slurry methods, metathesis methods, etc. Specifically, for example, the modified resin can be produced by reacting a polymer that forms the polymer backbone of the modified resin with a functional compound into which functional groups can be introduced, using known methods.

[0201] The polymer forming the polymer backbone is not particularly limited and may be, for example, the C5 resin, aromatic resin, or terpene resin mentioned above, or other resins. These may be used individually or in combination of two or more. Among these, aromatic resins are preferred, α-methylstyrene resins are more preferred, and styrene-α-methylstyrene resin (a copolymer of styrene and α-methylstyrene) is even more preferred.

[0202] The functional group is preferably one containing at least one element selected from the group consisting of oxygen, silicon, and nitrogen, and more preferably one containing silicon.

[0203] When the above rubber composition contains the above modified resin, the content of the modified resin is preferably 15 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 45 parts by mass or more, and also preferably 95 parts by mass or less, more preferably 75 parts by mass or less, and even more preferably 55 parts by mass or less, based on 100 parts by mass of the rubber component. When the content is within the above range, a better effect tends to be obtained.

[0204] Commercially available resins such as those from Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Arizona Chemical Company, Nippon Paint Chemical Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Corporation, Arakawa Chemical Industries, Ltd., and Taoka Chemical Industries, Ltd. can be used.

[0205] When the above rubber composition contains the above resin (a plasticizer resin), the resin content is preferably 15 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 45 parts by mass or more, and particularly preferably more than 50 parts by mass, per 100 parts by mass of the rubber component. Also, preferably 95 parts by mass or less, more preferably 75 parts by mass or less, and even more preferably 55 parts by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0206] In the above rubber composition, the silica content / resin (plasticizer resin) content is preferably 1.0 or more, more preferably 2.0 or more, even more preferably 2.5 or more, and also preferably 7.0 or less, more preferably 5.0 or less, and even more preferably 3.0 or less. When the value is within the above range, a better effect tends to be obtained. In this relationship, the silica content and resin content are expressed as the content per 100 parts by mass of the rubber component (unit: parts by mass).

[0207] In the above rubber composition, the ratio of the carbon black content to the resin (plasticizer resin) content is preferably 0.05 or more, more preferably 0.15 or more, even more preferably 0.20 or more, and also preferably 1.0 or less, more preferably 0.7 or less, and even more preferably 0.4 or less. When the ratio is within the above range, a better effect tends to be obtained. In this relationship, the carbon black content and resin content are expressed as the content per 100 parts by mass of the rubber component (unit: parts by mass).

[0208] Liquid polymers are (co)polymers that are liquid at 25°C, and examples include liquid rubber and liquid resin. Liquid resin is preferred among these. Liquid polymers may also undergo modification treatment or hydrogenation treatment. Commercial products from companies such as Cray Valley and Kuraray Co., Ltd. can be used. These may be used individually or in combination of two or more.

[0209] The weight-average molecular weight (Mw) of the liquid polymer is less than 10,000, preferably 9,000 or less, more preferably 6,000 or less, even more preferably 4,500 or less, and also preferably 100 or more, more preferably 1,000 or more, and even more preferably 2,000 or more. Within this range, better effects tend to be obtained.

[0210] When the above rubber composition contains a liquid polymer, the liquid polymer content is preferably 2 parts by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the rubber component. Within this range, a better effect tends to be obtained. In this specification, the liquid polymer is not included in the rubber component.

[0211] As the liquid rubber, at least one diene-based (co)polymer selected from the group consisting of butadiene, isoprene, styrene, farnesene, and derivatives thereof can be used. Specific examples include liquid diene-based polymers such as liquid styrene-butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), liquid styrene-isoprene copolymer (liquid SIR), liquid farnesene polymer, and liquid farnesene-butadiene copolymer.

[0212] The liquid rubber may be modified with functional groups that interact with silica, or its terminals and / or main chain may be modified with functional groups containing at least one element selected from the group consisting of oxygen, nitrogen, silicon, and phosphorus. Furthermore, the liquid rubber may be either unhydrogenated or hydrogenated.

[0213] When the above rubber composition contains liquid rubber, the liquid rubber content is preferably 2 parts by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, the effect tends to be better obtained.

[0214] The liquid resin is a resin that is liquid at 25°C, and any of the above-mentioned types of resins can be used. One type of liquid resin may be used alone, or two or more types of liquid resins may be used in combination.

[0215] When the above rubber composition contains a liquid resin, the liquid resin content is preferably 2 parts by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, the effect tends to be better obtained.

[0216] Examples of oils include mineral oil, vegetable oil, and animal oil. From a life cycle assessment perspective, waste oil used in rubber mixers and engines, or refined waste cooking oil used in restaurants, may also be used.

[0217] In this specification, mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. Examples of mineral oil include paraffinic oils (mineral oil), naphthenic oils, and aromatic oils. Specific examples of mineral oil include MES (Mild Extract Solvates), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), and RAE (Residual Aromatic Extract). Furthermore, for environmental reasons, oils with a low content of polycyclic aromatic compounds (PCA) can also be used. Examples of the low PCA-content oils include MES, TDAE, and heavy naphthenic oils.

[0218] In this specification, vegetable oils include, for example, linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice oil, tall oil, sesame oil, perilla oil, castor oil, tung oil, pine oil, pine tar oil, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grapeseed oil, and wood wax. Furthermore, vegetable oils may also include refined oils obtained by refining the above oils (such as salad oil), transesterified oils obtained by transesterifying the above oils, hydrogenated oils obtained by hydrogenating the above oils, thermally polymerized oils obtained by thermally polymerizing the above oils, oxidized polymerized oils obtained by oxidizing the above oils, and waste cooking oils recovered from use as edible oils. Note that vegetable oils may be liquid or solid at 25°C. These may be used individually or in combination of two or more types.

[0219] The vegetable oil according to this embodiment preferably contains acylglycerol, and more preferably contains triacylglycerol. In this specification, acylglycerol refers to a compound in which a hydroxyl group of glycerin and a fatty acid are ester-bonded. The acylglycerol is not particularly limited and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, the acylglycerol may be a monomer, a dimer, or a polymer of three or more. Note that acylglycerols of two or more mers can be obtained by thermal polymerization, oxidative polymerization, etc. Also, the acylglycerol may be a liquid or a solid at 25°C.

[0220] The method for confirming whether the rubber composition contains the acylglycerol is not particularly limited, １ This can be confirmed by H-NMR measurement. For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at 25°C for 24 hours, and after removing the rubber composition, it is observed at room temperature. １When 1H-NMR was measured and the signal for tetramethylsilane (TMS) was set to 0.00 ppm, signals were observed around 5.26 ppm, 4.28 ppm, and 4.15 ppm. These signals are presumed to originate from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atom of the ester group. In this paragraph, "around" refers to a range of ±0.10 ppm.

[0221] The aforementioned fatty acids are not particularly limited and may be either unsaturated or saturated fatty acids. Examples of unsaturated fatty acids include monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid. Examples of saturated fatty acids include butyric acid and lauric acid.

[0222] In particular, it is desirable that the fatty acid contains fatty acids with few double bonds, i.e., saturated fatty acids or monounsaturated fatty acids, and oleic acid is preferred. As a vegetable oil containing such fatty acids, for example, a vegetable oil containing saturated fatty acids or monounsaturated fatty acids may be used, or a vegetable oil that has been modified by transesterification or other means may be used. Furthermore, in order to produce a vegetable oil containing such fatty acids, plants may be improved by breeding, genetic modification, genome editing, etc.

[0223] As for vegetable oils, commercially available products from companies such as Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Fuji Kosan Co., Ltd., and Nisshin Oillio Group Ltd. can be used.

[0224] When the above rubber composition contains vegetable oil, the vegetable oil content is preferably 2 parts by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, a better effect tends to be obtained.

[0225] Commercially available oils that can be used include those from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Showa Shell Sekiyu K.K., Fuji Kosan Co., Ltd., Nisshin Oillio Group Ltd., and others.

[0226] If the above rubber composition contains oil, the oil content is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 25 parts by mass or more, and also preferably 55 parts by mass or less, more preferably 45 parts by mass or less, and even more preferably 35 parts by mass or less, per 100 parts by mass of the rubber component. When the oil content is within the above range, a better effect tends to be obtained.

[0227] The ester-based plasticizer is not particularly limited as long as it is a compound having an ester group that is in a liquid state at 25°C, but examples include phthalic acid derivatives, long-chain fatty acid derivatives, phosphoric acid derivatives, sebacic acid derivatives, and adipic acid derivatives. These may be used individually or in combination of two or more. Among these, phosphoric acid derivatives, sebacic acid derivatives, and adipic acid derivatives are preferred, with sebacic acid derivatives being more preferred. The above phthalic acid derivatives are not particularly limited, but examples include phthalic acid esters such as di-2-ethylhexyl phthalate (DOP) and diisodecyl phthalate (DIDP). The above long-chain fatty acid derivatives are not particularly limited, but examples include long-chain fatty acid glycerol esters. The above phosphate derivatives are not particularly limited, but examples include phosphate esters such as tris(2-ethylhexyl) phosphate (TOP) and tributyl phosphate (TBP). The above sebaciate derivatives are not particularly limited, but examples include sebaciate esters such as di(2-ethylhexyl) sebacate (DOS) and diisooctyl sebacate (DIOS). The above adipic acid derivatives are not particularly limited, but examples include adipic acid esters such as di(2-ethylhexyl) adipate (DOA) and diisooctyl adipate (DIOA). Among these, phosphate esters, sebacate esters, and adipic esters are preferred, with sebacate esters being more preferred. Furthermore, as specific compounds, TOP, DOS, and DOA are preferred, with DOS being more preferred. As ester-based plasticizers, for example, products from Daihachi Chemical Industry Co., Ltd., Taoka Chemical Industry Co., Ltd., etc., can be used.

[0228] The glass transition temperature (Tg) of the ester-based plasticizer is preferably -110°C or higher, more preferably -100°C or higher, even more preferably -80°C or higher, preferably -20°C or lower, more preferably -40°C or lower, and even more preferably -55°C or lower. The above effects tend to be more favorably obtained by keeping the temperature within this range. In this specification, the glass transition temperature of the ester-based plasticizer is the value measured in accordance with JIS-K7121 using a differential scanning calorimeter (Q200) manufactured by T.A. Instruments Japan Co., Ltd., under a heating rate of 10°C / min.

[0229] If the above rubber composition contains an ester-based plasticizer, the amount of ester-based plasticizer is preferably 1 to 20 parts by mass per 100 parts by mass of the rubber component.

[0230] If the above rubber composition contains a plasticizer, the plasticizer content is preferably 30 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 70 parts by mass or more, and preferably 120 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 80 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, the effect tends to be better obtained.

[0231] In the above rubber composition, the value of the filler content / plasticizer content is preferably 1.0 or more, more preferably 1.4 or more, even more preferably 1.8 or more, and also preferably 3.0 or less, more preferably 2.5 or less, and even more preferably 2.1 or less. When the value is within the above range, a better effect tends to be obtained. In this relationship, the filler and plasticizer content are expressed as the content per 100 parts by mass of the rubber component (unit: parts by mass).

[0232] The above rubber composition may contain a silane coupling agent. The silane coupling agent is not particularly limited and includes, for example, bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl) trisulfide, bis(4-trimethoxysilylbutyl) trisulfide, bis(3-triethoxysilylpropyl) disulfide, bis(2-triethoxysilylethyl) disulfide, bis(4-triethoxysilylbutyl) disulfide, bis(3-trimethoxysilylpropyl) disulfide, bis(2-trimethoxysilylethyl) disulfide, bis(4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl Examples include sulfide-based compounds such as ropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, and 3-triethoxysilylpropyl methacrylate monosulfide; mercapto-based compounds such as 3-mercaptopropyltrimethoxysilane and 2-mercaptoethyltriethoxysilane; vinyl-based compounds such as vinyltriethoxysilane and vinyltrimethoxysilane; amino-based compounds such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; glycidoxy-based compounds such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based compounds such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro-based compounds such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. Among these, mercapto-based compounds are preferred. Commercially available products include those from companies such as Evonik, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azumax Co., Ltd., and Toray Dow Corning Co., Ltd. These can be used individually or in combination of two or more types.

[0233] In addition to compounds containing a mercapto group, compounds in which the mercapto group is protected by a protecting group (for example, compounds represented by the following formula (S1)) can also be used as mercapto-silane coupling agents.

[0234] Particularly suitable mercapto-silane coupling agents include silane coupling agents represented by the following formula (S1), and silane coupling agents containing a bonding unit A shown in the following formula (I) and a bonding unit B shown in the following formula (II). (In the formula, R １００１ -Cl, -Br, -OR １００６ , -O(O=)CR １００６ , -ON=CR １００６ R １００７ , -NR １００６ R １００７ and - (OSiR １００６ R １００７ ) ｈ (OSiR １００６ R １００７ R １００８ A monovalent group (R) selected from ) １００６ , R １００７ and R １００８ They may be the same or different, and each is a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms, and h has an average value of 1 to 4. １００２ is R １００１ , hydrogen atom or monovalent hydrocarbon group having 1 to 18 carbon atoms, R １００３ ha-[O(R １００９ O) ｊ ]-group (R １００９ is an alkylene group having 1 to 18 carbon atoms, and j is an integer from 1 to 4. ), R １００４ R is a divalent hydrocarbon group having 1 to 18 carbon atoms. １００５ (where represents a monovalent hydrocarbon group with 1 to 18 carbon atoms, and x, y, and z are numbers that satisfy the relationships x + y + 2z = 3, 0 ≤ x ≤ 3, 0 ≤ y ≤ 2, and 0 ≤ z ≤ 1.) (In the formula, v is a non-negative integer and w is a non-negative integer. R １１R represents hydrogen, halogen, branched or unbranched C1-C30 alkyl group, branched or unbranched C2-C30 alkenyl group, branched or unbranched C2-C30 alkynyl group, or an alkyl group in which the terminal hydrogen is substituted with a hydroxyl group or a carboxyl group. １２ R represents a branched or unbranched alkylene group having 1 to 30 carbon atoms, a branched or unbranched alkenylene group having 2 to 30 carbon atoms, or a branched or unbranched alkynylene group having 2 to 30 carbon atoms. １１ and R １２ (They may form a ring structure.)

[0235] In equation (S1), R １００５ , R １００６ , R １００７ and R １００８ Each of these is preferably independently selected from the group consisting of linear, cyclic, or branched alkyl, alkenyl, aryl, and aralkyl groups having 1 to 18 carbon atoms. １００２ If is a monovalent hydrocarbon group having 1 to 18 carbon atoms, it is preferably a group selected from the group consisting of linear, cyclic, or branched alkyl groups, alkenyl groups, aryl groups, and aralkyl groups. １００９ The alkylene group is preferably linear, cyclic, or branched, and is particularly preferred to be linear. １００４ Examples of R include alkylene groups having 1 to 18 carbon atoms, alkenylene groups having 2 to 18 carbon atoms, cycloalkylene groups having 5 to 18 carbon atoms, cycloalkylalkylene groups having 6 to 18 carbon atoms, arylene groups having 6 to 18 carbon atoms, and aralkylene groups having 7 to 18 carbon atoms. The alkylene groups and alkenylene groups may be linear or branched, and the cycloalkylene groups, cycloalkylalkylene groups, arylene groups, and aralkylene groups may have functional groups such as lower alkyl groups on their rings. １００４ Preferably, the alkylene group has 1 to 6 carbon atoms, and in particular, linear alkylene groups such as methylene, ethylene, trimethylene, tetramethylene, pentamethylene, and hexamethylene groups are preferred.

[0236] R in equation (S1) １００２ , R１００５ , R １００６ , R １００７ and R １００８ Specific examples include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group, decyl group, dodecyl group, cyclopentyl group, cyclohexyl group, vinyl group, propenyl group, allyl group, hexenyl group, octenyl group, cyclopentenyl group, cyclohexenyl group, phenyl group, tolyl group, xylyl group, naphthyl group, benzyl group, phenethyl group, naphthylmethyl group, etc. In formula (S1), R １００９ Examples of linear alkylene groups include methylene, ethylene, n-propylene, n-butylene, and hexylene groups, while examples of branched alkylene groups include isopropylene, isobutylene, and 2-methylpropylene groups.

[0237] Specific examples of silane coupling agents represented by formula (S1) include 3-hexanoylthiopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, 3-lauroylthiopropyltriethoxysilane, 2-hexanoylthioethyltriethoxysilane, 2-octanoylthioethyltriethoxysilane, 2-decanoylthioethyltriethoxysilane, 2-lauroylthioethyltriethoxysilane, 3-hexanoylthiopropyltrimethoxysilane, 3-octanoylthiopropyltrimethoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltrimethoxysilane, 2-hexanoylthioethyltrimethoxysilane, 2-octanoylthioethyltrimethoxysilane, 2-decanoylthioethyltrimethoxysilane, and 2-lauroylthioethyltrimethoxysilane. These may be used individually or in combination of two or more. Among them, 3-octanoylthiopropyltriethoxysilane is particularly preferred.

[0238] In a silane coupling agent containing a bonding unit A represented by formula (I) and a bonding unit B represented by formula (II), the content of bonding unit A is preferably 30 mol% or more, more preferably 50 mol% or more, preferably 99 mol% or less, and more preferably 90 mol% or less. The content of bonding unit B is preferably 1 mol% or more, more preferably 5 mol% or more, even more preferably 10 mol% or more, preferably 70 mol% or less, more preferably 65 mol% or less, and even more preferably 55 mol% or less. The total content of bonding units A and B is preferably 95 mol% or more, more preferably 98 mol% or more, and particularly preferably 100 mol%. Note that the content of bonding units A and B includes the amount when bonding units A and B are located at the ends of the silane coupling agent. The form in which bonding units A and B are located at the ends of the silane coupling agent is not particularly limited, as long as they form units corresponding to formulas (I) and (II) representing bonding units A and B.

[0239] R in equations (I) and (II) １１ Examples of halogens include chlorine, bromine, and fluorine. Examples of branched or unbranched alkyl groups having 1 to 30 carbon atoms include methyl and ethyl groups. Examples of branched or unbranched alkenyl groups having 2 to 30 carbon atoms include vinyl and 1-propenyl groups. Examples of branched or unbranched alkynyl groups having 2 to 30 carbon atoms include ethynyl and propynyl groups.

[0240] R in equations (I) and (II) １２ Regarding branched or unbranched alkylene groups having 1 to 30 carbon atoms, examples include ethylene groups and propylene groups. Regarding branched or unbranched alkenylene groups having 2 to 30 carbon atoms, examples include vinylene groups and 1-propenylene groups. Regarding branched or unbranched alkylene groups having 2 to 30 carbon atoms, examples include ethynylene groups and propynylene groups.

[0241] In a silane coupling agent comprising a bonding unit A represented by formula (I) and a bonding unit B represented by formula (II), the sum of the number of repeats of bonding unit A (v) and the number of repeats of bonding unit B (w), (v + w), is preferably in the range of 3 to 300.

[0242] When the above rubber composition contains a silane coupling agent, the content of the silane coupling agent is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, even more preferably 6.4 parts by mass or more, and preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 7.5 parts by mass or less, per 100 parts by mass of silica. When the content is within the above range, a better effect tends to be obtained.

[0243] The above rubber composition may contain processing aids. Examples of processing aids include metal salts (compounds in which the hydrogen atoms of an acid are replaced by metal ions), fatty acid amides, amide esters, and fatty acid esters. These may be used individually or in combination of two or more.

[0244] Examples of metals used in metal salts include alkali metals such as potassium and sodium, and alkaline earth metals such as calcium and barium. Magnesium, zinc, nickel, and molybdenum can also be used. Among these, zinc is preferred.

[0245] Acids used in metal salts include, for example, fatty acids such as lauric acid, myristic acid, and palmitic acid. Boric acid, carbonic acid, hydrochloric acid, nitric acid, and sulfuric acid can also be used. Among these, fatty acids are preferred.

[0246] Commercially available processing aids include products from Kishida Chemical Co., Ltd., Ken-ei Pharmaceutical Co., Ltd., Structol Inc., Performance Additives Inc., and others.

[0247] If the above rubber composition contains a processing aid, the amount of the processing aid is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 4 parts by mass or more, per 100 parts by mass of the rubber component, and also preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less. When the amount is within the above range, a better effect tends to be obtained.

[0248] The above rubber composition may contain an antioxidant. The antioxidant is not particularly limited, but may include naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), and N,N'-ditril-p-phenylenediamine. Examples include p-phenylenediamine-based antioxidants such as methyl amine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based antioxidants such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; and bis, tris, and polyphenol-based antioxidants such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane. Among these, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferred, and polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. Commercially available products include, for example, those from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Co., Ltd., and Flexis Co., Ltd. These may be used individually or in combination of two or more.

[0249] When the above rubber composition contains an antioxidant, the amount of the antioxidant is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 4.5 parts by mass or more, and preferably 15 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 6 parts by mass or less, per 100 parts by mass of the rubber component. When the amount is within the above range, the effect tends to be better obtained.

[0250] The above rubber composition may contain wax. The wax is not particularly limited, and any wax commonly used in the tire industry can be suitably used. Examples include mineral waxes and plant-derived waxes. Mineral waxes refer to waxes derived from mineral resources such as oil and natural gas. Plant-derived waxes refer to waxes derived from natural resources such as plants. Among these, mineral waxes are preferred. Examples of plant-derived waxes include rice wax, carnauba wax, and candelilla wax. Examples of mineral waxes include paraffin wax, microcrystalline wax, and selected special waxes thereof, with paraffin wax being preferred. The wax according to this embodiment does not contain stearic acid. The wax can be commercially available from companies such as Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., and Paramelt Co., Ltd. These waxes may be used individually or in combination of two or more types.

[0251] The wax is preferably obtained as a by-product of Fischer-Tropsch synthesis derived from natural gas. The raw materials for Fischer-Tropsch synthesis may also be recycled methane (such as methane obtained by thermal decomposition of tires) or biomass-derived methane (such as methane obtained from carbon dioxide through a methanation process).

[0252] If the above rubber composition contains wax, the wax content is preferably 1 part by mass or more, more preferably 2.5 parts by mass or more, and preferably 8 parts by mass or less, and more preferably 4 parts by mass or less, per 100 parts by mass of the rubber component. When the wax content is within the above range, the effect tends to be better.

[0253] The above rubber composition may contain stearic acid. Conventional known stearic acid can be used, and commercially available products from companies such as NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Industries, and Chiba Fatty Acid Co., Ltd. can be used. These may be used individually or in combination of two or more.

[0254] The stearic acid content is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 8 parts by mass or less, and more preferably 5 parts by mass or less, per 100 parts by mass of the rubber component. Within this range, a better effect tends to be obtained.

[0255] The above rubber composition may contain zinc oxide. Conventional known zinc oxides can be used, and commercially available products from companies such as Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., and Sakai Chemical Industry Co., Ltd. can be used. These may be used individually or in combination of two or more types.

[0256] When the above rubber composition contains zinc oxide, the zinc oxide content is preferably 1 part by mass or more, more preferably 2.5 parts by mass or more, and preferably 10 parts by mass or less, and more preferably 5 parts by mass or less, per 100 parts by mass of the rubber component. Within this range, a better effect tends to be obtained.

[0257] The above rubber composition may contain sulfur. Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and soluble sulfur, which are commonly used as crosslinking agents in the rubber industry. Commercially available products include those from Tsurumi Chemical Industries, Karuizawa Sulfur Co., Ltd., Shikoku Chemicals, Ltd., Flexis Co., Ltd., Nippon Dry Distillation Co., Ltd., and Hosoi Chemical Industry Co., Ltd. These may be used individually or in combination of two or more.

[0258] If the above rubber composition contains sulfur, the sulfur content is preferably 0.5 parts by mass or more, more preferably 1.5 parts by mass or more, and preferably 10 parts by mass or less, and more preferably 5 parts by mass or less, per 100 parts by mass of the rubber component. Within this range, a better effect tends to be obtained.

[0259] The above rubber composition preferably contains a dibenzylamine compound. The dibenzylamine compound is a compound having at least one group represented by the following formula (a dibenzylamine group).

[0260] Specific examples of dibenzylamine compounds include dibenzylamine, tetrabenzylthium disulfide (TBzTD), zinc dibenzyldithiocarbamate, and 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane. Commercially available products include those from Sanshin Chemical Industry Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., and Lanxess. These may be used individually or in combination of two or more. Among these, compounds having two dibenzylamine groups are preferred.

[0261] When the above rubber composition contains a dibenzylamine compound, the content of the dibenzylamine compound is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, even more preferably 1.5 parts by mass or more, and also preferably 5 parts by mass or less, more preferably 4 parts by mass or less, and even more preferably 3 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, the effect tends to be better obtained.

[0262] The above rubber composition may contain a dialkyldithiophosphate compound. As the dialkyldithiophosphate compound, for example, a salt of dialkyldithiophosphate with a metal such as zinc or molybdenum can be used. As a commercially available product, products such as TP-50 manufactured by Rhein Chemie can be used. These may be used individually or in combination of two or more. Among these, the compound represented by the following formula (1) (zinc dialkyldithiophosphate) is preferred. (In the formula, R １ ~R ４ Each of these independently represents a linear or branched alkyl group having 1 to 18 carbon atoms, or a cycloalkyl group having 5 to 12 carbon atoms.

[0263] In equation (1), R １ ~R ４Examples of linear or branched alkyl groups represented by include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, 4-methylpentyl group, 2-ethylhexyl group, octyl group, octadecyl group, etc., while examples of cycloalkyl groups include cyclopentyl group, cyclohexyl group, cyclooctyl group, etc. Among these, R is particularly suitable because it is easily dispersed in rubber compositions and easy to manufacture. １ ~R ４ The group is preferably a linear or branched alkyl group having 2 to 8 carbon atoms, more preferably an n-butyl group, an n-propyl group, an iso-propyl group, or an n-octyl group, and even more preferably an n-butyl group.

[0264] When the above rubber composition contains a dialkyldithiophosphate compound, the content of the dialkyldithiophosphate compound is preferably 0.1 to 10 parts by mass per 100 parts by mass of the rubber component. Within this range, a better effect tends to be obtained.

[0265] The above rubber composition may contain a vulcanization accelerator. Examples of vulcanization accelerators include benzothiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole and di-2-benzothiazolyl disulfide; thiram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD) and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiadylsulfenamide (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-oxyethylene-2-benzothiazolesulfenamide, and N,N'-diisopropyl-2-benzothiazolesulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, diortotolylguanidine, and orthotolylbiguanidine. Commercially available products from companies such as Sumitomo Chemical Co., Ltd. and Ouchi Shinko Chemical Co., Ltd. can be used. These can be used individually or in combination of two or more.

[0266] When the above rubber composition contains a vulcanization accelerator, the amount of the vulcanization accelerator is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 4.5 parts by mass or more, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of the rubber component. When the amount is within the above range, the effect tends to be better obtained.

[0267] In addition to the above components, the above rubber composition may further contain additives commonly used in the tire industry, such as organic peroxides. The content of these additives is preferably 0.1 to 200 parts by mass per 100 parts by mass of the rubber component.

[0268] In this specification, various materials containing carbon atoms (e.g., rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) may be derived from atmospheric carbon dioxide. As a method for obtaining the above formulations from carbon dioxide, carbon dioxide may be directly converted, or methane obtained through a methanation process in which methane is synthesized from carbon dioxide may be converted.

[0269] The above rubber composition can be produced, for example, by kneading each of the above components using a rubber kneading device such as an open roll or Banbury mixer, and then vulcanizing it.

[0270] Regarding the mixing conditions, in the base mixing step where additives other than the vulcanizing agent and vulcanization accelerator are mixed, the mixing temperature is usually 100 to 180°C, preferably 120 to 170°C. In the finish mixing step where the vulcanizing agent and vulcanization accelerator are mixed, the mixing temperature is usually 120°C or lower, preferably 85 to 110°C. Furthermore, the composition mixed with the vulcanizing agent and vulcanization accelerator is usually subjected to a vulcanization treatment such as press vulcanization. The vulcanization temperature is usually 140 to 190°C, preferably 150 to 185°C. The vulcanization time is usually 5 to 15 minutes.

[0271] The above rubber composition can be used (as a tire rubber composition) in tire components such as treads, sidewalls, undertreads, shoulders, clinches, bead apex, breaker cushion rubber, carcass cord covering rubber, insulation, chafers, inner liners, and side reinforcement layers of run-flat tires.

[0272] (Pneumatic Tire) The present invention also relates to a pneumatic tire made using the above rubber composition. The above pneumatic tire can be manufactured using the above rubber composition by a conventional method. That is, the rubber composition is extruded to match the shape of the above tire components at the unvulcanized stage, molded on a tire molding machine by a conventional method, and bonded together with other tire components to form an unvulcanized tire. This unvulcanized tire can be heated and pressurized in a vulcanizing machine to manufacture a tire.

[0273] The present invention will be specifically described based on the examples provided, but the present invention is not limited to these examples.

[0274] Example 1 <Gene Acquisition> (Acquisition of Sapodilla-derived trans-prenyltransferase gene) To acquire a gene for trans-prenyltransferase that synthesizes high molecular weight trans-1,4-polyisoprene, a de novo assembly was performed on the transcriptome database of Sapodilla that synthesize high molecular weight trans-1,4-polyisoprene. A gene similar to the trans-prenyltransferase gene from Arabidopsis thaliana was searched for, and MztPT2 was discovered. To optimize expression in E. coli, the codons were optimized for E. coli, and then the MztPT2ΔN158 gene was designed by deleting base sequences 1 to 474 (amino acids 1 to 158), and gene synthesis was performed. Sequence ID 1 shows the base sequence of the gene encoding the synthesized Sapodilla-derived transprenyltransferase (MztPT2) mutant, and Sequence ID 2 shows the amino acid sequence of the synthesized Sapodilla-derived transprenyltransferase (MztPT2) mutant.

[0275] <Construction Preparation> (Preparation of the MzTPT2ΔN158 construct for expression in E. coli) The synthesized gene was introduced into the multicloning site of pCold1 (TaKara, Japan) and fused with a His-tag at the N-terminus.

[0276] <Enzyme Expression> The prepared gene construct was introduced into E. coli BL21. The E. coli with the introduced gene was cultured in LB medium at 37°C with shaking. When the absorbance (OD600) measured at 600 nm reached 0.5, IPTG was added to a final concentration of 0.5 mM, and the culture temperature was further reduced to 15°C, followed by 40-45 hours of culture with shaking.

[0277] <Enzyme Purification> After recovering E. coli by centrifugation, the cells were resuspended in 100 mM Tris-HCl (pH 7.5), and then the E. coli were lysed to obtain a crude enzyme solution. The enzyme was purified using a HisTrapHP column (Cytiva, Japan).

[0278] Example 2 The method for producing the enzyme was the same as in Example 1.

[0279] <Enzyme Activity Measurement> To measure the activity of the prenyl chain extension enzyme, a reaction solution was prepared and reacted, and then the radioactivity was measured using a liquid scintillation counter to determine the IPP (isopentenyl diphosphate) uptake activity. The prepared enzyme-bound membrane particle solution was reacted at 30°C for 30 minutes with the following reaction solution composition containing [4-14C]IPP (NEC773, Perkin Elmer).

[0280] Reaction solution composition Tris-HCl (pH 7.5) (buffer) 50mM DTT (reducing agent) 2mM MgCl ２ 5mM HC≡C-CH ２ O-(CH ２ -C(CH ３ ) = CH - CH ２ ) ３ - Tetrabutylamine salt of OPP (click reaction substrate) ＊ ) 15 μM [4- １４C] IPP (5Ci / mol) 50 μM Triton X-100 (surfactant) 2 × CMC ＊＊ MzTPT2ΔN158 solution 0.2μg (protein amount) Ultrapure water up to 100μL ＊ As the click reaction substrate, we used TargetMol's C15AlkOPP t-BA salt (catalog number T30677L). ＊＊ CMC = critical micelle concentration. In the case of Triton X-100, CMC = 0.24 mM. In molar concentration notation, 2 × CMC = 0.48 mM.

[0281] <Product Extraction> After the reaction, the reaction was stopped by adding 200 μL of saturated saline solution and stirring. 1 mL of saturated n-butanol was added to the saturated saline solution, and the mixture was vortexed for 1 minute. After centrifugation at 15,000 rpm at room temperature for 1 minute, the upper butanol layer was collected to extract products down to the dolichol size, which is shorter than natural rubber. Subsequently, 500 μL of tetrahydrofuran was added to the aqueous layer, and the mixture was vortexed for 5 minutes. After centrifugation at 15,000 rpm at room temperature for 1 minute, the upper layer (tetrahydrofuran layer) was collected to extract products down to the natural rubber size. This tetrahydrofuran extraction was performed twice, extracting a total of 1 mL of tetrahydrofuran layer. 50 μL of each extract was added to 3 mL of ClearZol, and the radioactivity was measured using a liquid scintillation counter (LSC-6100, ALOKA). The total count of the extract was calculated by subtracting the background value from the measured value and multiplying by 20 (since 50 μL of 1 mL was measured).

[0282] Example 2 was the same as Example 1, except that it was the reaction solution with MztPT2 as in Example 1, and did not contain Triton X-100 (surfactant).

[0283] [Test Results] Figure 1 shows the difference in the amount of product produced between Example 1 and Example 2.

[0284] Figure 2 shows the GPC analysis results of the tetrahydrofuran extract from Example 1. The molecular weight (weight-average molecular weight) of the product is 10,000 (10 ４ It was around that time.

[0285] Examples 1 and 2 yielded polyisoprenoids having click-reactive functional groups (alkyne moieties), which are thought to be capable of crosslinking with fillers such as silica. By forming crosslinks with fillers, polyisoprenoids can suppress molecular motion at the crosslinking sites, and it is thought that incorporating them into tire rubber compositions, for example, can improve the fuel efficiency of the tires.

[0286] The present invention (1) is a polyisoprenoid represented by the following formula (1). １ C≡CR (1) In formula (1), R １ represents a hydrogen atom or an organic group. R represents an organic chain having repeating units represented by the following formula (2). The end of the organic chain may be a functional group having a heteroatom. -(CH ２ -C(CH ３ ) = CH - CH ２ ) - (2)

[0287] The present invention (2) is R １ However, it is a polyisoprenoid as described in (1) of the present invention, which represents a hydrogen atom.

[0288] The present invention (3) is a polyisoprenoid according to the present invention (1) or (2), represented by the following formula (3): HC≡C-CH ２ -O-(CH ２ -C(CH ３ ) = CH - CH ２ ) ｎ -Y (3) In equation (3), Y represents a functional group having a heteroatom. n is an integer of 2 or more.

[0289] The present invention (4) is a polyisoprenoid according to the present invention (3), wherein Y in formula (3) represents a hydroxyl group, a formyl group, a carboxyl group, an alkoxycarboxyl group, an alkoxycarbonyl group, or an OPP group.

[0290] The present invention (5) is a polyisoprenoid according to any of the present inventions (1) to (4), represented by the following formula (4). １ C≡C-X-(CH ２ -C(CH ３ ) = CH - CH ２ ) ｎ-OPP (4) In formula (4), R １ R in formula (1) is １ It is similar to the above. X represents a direct bond or a divalent linking group. n is an integer greater than or equal to 2.

[0291] The present invention (6) is a polyisoprenoid according to any one of the present inventions (1) to (5), having a weight-average molecular weight of 600 or more.

[0292] The present invention (7) is a method for producing polyisoprenoids using prenyltransferase from a substrate represented by the following formula (5) and a compound represented by the following formula (6). １ C≡CR (5) In formula (5), R １ represents a hydrogen atom or an organic group. R represents an organic chain having repeating units represented by the following formula (7). The ends of the organic chain are OPP. - (CH ２ -C(CH ３ ) = CH - CH ２ ) - (7)

[0293] The present invention (8) is that in formula (5) above, R １ However, this is a manufacturing method described in (7) of the present invention, which represents a hydrogen atom.

[0294] The present invention (9) is a manufacturing method described in the present invention (7), wherein the substrate represented by formula (5) is represented by the following formula (8). １ C≡C-X-(CH ２ -C(CH ３ ) = CH - CH ２ ) ｍ -OPP (8) In formula (8), R １ represents a hydrogen atom or an organic group. X represents a direct bond or a divalent linking group. m is an integer from 1 to 10.

[0295] The present invention (10) is that in formula (8) above, R １ This represents a hydrogen atom, and is the manufacturing method described in (9) of the present invention.

[0296] In the present invention (11), in formula (8), X is CH ２ This is a manufacturing method described in (9) or (10) of the present invention, representing O.

[0297] The present invention (12) is a manufacturing method according to any one of the present inventions (7) to (11), wherein the weight-average molecular weight of the polyisoprenoid is 600 or more.

[0298] The present invention (13) further relates to a manufacturing method according to any one of the present inventions (7) to (12) that uses a surfactant.

[0299] The present invention (14) is a manufacturing method according to any one of the present inventions (7) to (13), wherein the prenyltransferase is a trans-type prenyltransferase.

[0300] The present invention (15) is a production method according to the present invention (14), wherein the trans-type prenyltransferase is a variant of sapodilla-derived transprenyltransferase (MztPT2).

[0301] The present invention (16) is a manufacturing method according to any one of the present inventions (7) to (13), wherein the prenyltransferase is a cis-type prenyltransferase.

[0302] The present invention (17) is a production method according to the present invention (16), wherein the cis-type prenyltransferase is a mutant of tomato-derived neryl phosphate synthase (NDPS1).

[0303] The present invention (18) is a manufacturing method according to the present invention (16), wherein the cis-type prenyltransferase is derived from rubber tree, Russian dandelion, or guayule.

[0304] (Sequence listing free text) SEQ ID NO: 1: Base sequence of the gene encoding a variant of sapodilla-derived transprenyltransferase (MztPT2) SEQ ID NO: 2: Amino acid sequence of the variant of sapodilla-derived transprenyltransferase (MztPT2)

Claims

1. A polyisoprenoid represented by the following formula (1). R １ C≡CR (1) In formula (1), R １ represents a hydrogen atom or an organic group. R represents an organic chain having repeating units represented by the following formula (2). The end of the organic chain may be a functional group having a heteroatom. -(CH ２ -C(CH ３ ) = CH - CH ２ ) - (2) 2. The aforementioned R １ However, the polyisoprenoid according to claim 1, which represents a hydrogen atom.

3. The polyisoprenoid according to claim 1 or 2, which is represented by the following formula (3). HC≡C-CH ２ -O-(CH ２ -C(CH ３ )=CH-CH ２ ) ｎ -Y (3) In the formula (3), Y represents a functional group having a heteroatom. n is an integer of 2 or more.

4. The polyisoprenoid according to claim 3, wherein Y in formula (3) represents a hydroxyl group, a formyl group, a carboxyl group, an alkoxycarboxyl group, an alkoxycarbonyl group, or an OPP group.

5. A polyisoprenoid according to any one of claims 1 to 4, represented by the following formula (4). １ C≡C-X-(CH ２ -C(CH ３ ) = CH - CH ２ ) ｎ -OPP (4) In formula (4), R １ R in formula (1) is １ It is similar to the above. X represents a direct bond or a divalent linking group. n is an integer greater than or equal to 2.

6. The polyisoprenoid according to any one of claims 1 to 5, wherein the weight-average molecular weight is 600 or more.

7. A method for producing polyisoprenoids using prenyltransferase from a substrate represented by the following formula (5) and a compound represented by the following formula (6). １ C≡CR (5) In formula (5), R １ represents a hydrogen atom or an organic group. R represents an organic chain having repeating units represented by the following formula (7). The ends of the organic chain are OPP. - (CH ２ -C(CH ３ ) = CH - CH ２ ) - (7) 8. In formula (5) above, R １ The manufacturing method according to claim 7, wherein the hydrogen atom is represented.

9. The substrate represented by formula (5) is represented by the following formula (8), in the manufacturing method according to claim 7. １ C≡C-X-(CH ２ -C(CH ３ ) = CH - CH ２ ) ｍ -OPP (8) In formula (8), R １ represents a hydrogen atom or an organic group. X represents a direct bond or a divalent linking group. m is an integer from 1 to 10.

10. In formula (8) above, R １ The manufacturing method according to claim 9, wherein is a hydrogen atom.

11. In equation (8) above, X is CH ２ The manufacturing method according to claim 9 or 10, representing O.

12. The manufacturing method according to any one of claims 7 to 11, wherein the weight-average molecular weight of the polyisoprenoid is 600 or more.

13. The manufacturing method according to any one of claims 7 to 12, further comprising the use of a surfactant.

14. The manufacturing method according to any one of claims 7 to 13, wherein the prenyltransferase is a trans-type prenyltransferase.

15. The method for producing the product according to claim 14, wherein the trans-type prenyltransferase is a variant of sapodilla-derived transprenyltransferase (MztPT2).

16. The manufacturing method according to any one of claims 7 to 13, wherein the prenyltransferase is a cis-type prenyltransferase.

17. The production method according to claim 16, wherein the cis-type prenyltransferase is a mutant of tomato-derived neryl phosphate synthase (NDPS1).

18. The manufacturing method according to claim 16, wherein the cis-type prenyltransferase is derived from rubber tree, dandelion, or guayule.

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