Resin member for tire, bead member, belt for tire, tire frame, tire, and manufacturing method thereof

Abstract

A tire resin member manufacturing method comprising: a molding step for molding a tire resin member containing a resin of at least one of a thermoplastic elastomer and a thermoplastic resin; and an electron beam irradiation step for irradiating the resin with an electron beam at least before, after, or during the molding step.

Description

[Technical field]

[0001] The present disclosure relates to a tire resin member, a bead member, a tire belt, a tire frame, and a tire, as well as methods for manufacturing these. [Background technology]

[0002] Conventionally, tires used for vehicles such as passenger cars have been studied using resin materials, particularly thermoplastic resin materials such as thermoplastic resins and thermoplastic elastomers, from the viewpoints of weight reduction, ease of molding, ease of recycling, etc. These thermoplastic resin materials have many advantages from the viewpoint of improving productivity, such as the ability to be injection molded.

[0003] For example, a tire has been proposed that is formed from a thermoplastic resin material and has a ring-shaped tire frame, which has reinforcing cord members that are wound circumferentially around the outer periphery of the tire frame to form a reinforcing cord layer, and the thermoplastic resin material contains at least a polyester-based thermoplastic elastomer (see JP 2012-46025 A). Summary of the Invention [Problem to be solved by the invention]

[0004] In tires manufactured using resin materials, such as the tire disclosed in JP 2012-46025 A, the state of the resin material in the manufactured tire affects the characteristics (durability, etc.) of the tire. Therefore, if the state of the resin material can be appropriately controlled, it is believed that the tire characteristics (durability, etc.) can be improved to a desired state. However, there is still room for study as to from what perspective the state of the resin material should be controlled to achieve the desired characteristics.

[0005] In view of the above circumstances, an object of the present disclosure is to provide a tire resin member that has excellent durability (particularly crack resistance) when made into a tire, as well as a bead component, a tire belt, a tire frame, and a tire, each of which has the tire resin member. Another object of the present invention is to provide a method for producing a tire resin member that provides a tire resin member having excellent durability (particularly crack resistance) when made into a tire having the tire resin member, as well as a method for producing a bead member having the tire resin member, a method for producing a tire belt, a method for producing a tire frame, and a method for producing a tire. [Means for solving the problem]

[0006] Specific means for solving the above problems include the following aspects.

[0007] [1] A molding step of molding a tire resin member containing at least one resin selected from a thermoplastic elastomer and a thermoplastic resin; an electron beam irradiation step of irradiating the resin with an electron beam at least either before, after, or during the molding step; Including, A method for producing a tire resin member. Effect of the Invention

[0008] According to the present disclosure, there are provided a tire resin member that has excellent durability (particularly crack resistance) when made into a tire having the tire resin member, as well as a bead component, a tire belt, a tire frame, and a tire, each of which has the tire resin member. Also provided are a method for producing a tire resin member, which provides a tire resin member having excellent durability (particularly crack resistance) when made into a tire having the tire resin member, as well as a method for producing a bead member having the tire resin member, a method for producing a tire belt, a method for producing a tire frame, and a method for producing a tire. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic diagram of a cross section perpendicular to the longitudinal direction of a bead wire, showing an example of a bead member according to the present embodiment. [Diagram 2] 1 is a cross-sectional view taken along the tire width direction, illustrating an example of a configuration of a tire including a tire belt according to an embodiment of the present invention. [Diagram 3] 1 is a perspective view showing a cross section of a portion of a tire including a tire frame according to an embodiment of the present invention. FIG. [Figure 4] 3 is a cross-sectional view of the bead member according to the embodiment attached to a rim. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present disclosure will be described. These descriptions and examples are merely illustrative of the embodiments, and are not intended to limit the scope of the embodiments.

[0011] In the present disclosure, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In the numerical ranges described in the present disclosure in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples. In the present disclosure, the term "process" includes not only an independent process, but also a process that cannot be clearly distinguished from other processes, as long as the process achieves its purpose.

[0012] In the present disclosure, each component may contain multiple types of corresponding substances. When referring to the amount of each component in a composition in the present disclosure, if multiple substances corresponding to each component are present in the composition, the total amount of the multiple substances present in the composition is meant unless otherwise specified.

[0013] In this disclosure, the term "resin" refers to a concept that includes thermoplastic resins, thermoplastic elastomers, and thermosetting resins, and does not include vulcanized rubber. In the following description of resins, "same type" refers to resins that have a common skeleton that constitutes the main chain of the resin, such as ester-based resins or styrene-based resins.

[0014] In this disclosure, "thermoplastic resin" refers to a polymeric compound that softens and flows as the temperature increases and becomes relatively hard and strong when cooled, but does not have rubber-like elasticity.

[0015] In the present disclosure, the term "thermoplastic elastomer" refers to a copolymer having a hard segment and a soft segment. Examples of thermoplastic elastomers include those that soften and flow with increasing temperature, become relatively hard and strong when cooled, and have rubber-like elasticity. Specific examples of thermoplastic elastomers include copolymers having a polymer that constitutes a crystalline hard segment with a high melting point or a hard segment with high cohesive strength, and a polymer that constitutes an amorphous soft segment with a low glass transition temperature.

[0016] The hard segment refers to a component that is relatively harder than the soft segment. The hard segment is preferably a molecular restraining component that serves as a cross-linking point of the cross-linked rubber to prevent plastic deformation. For example, the hard segment may be a segment having a structure having a rigid group such as an aromatic group or an alicyclic group in the main skeleton, or a structure that enables intermolecular packing by intermolecular hydrogen bonding or π-π interaction.

[0017] The soft segment refers to a component that is relatively softer than the hard segment. The soft segment is preferably a flexible component exhibiting rubber elasticity. For example, the soft segment may be a segment having a long-chain group (e.g., a long-chain alkylene group) in the main chain, with a high degree of freedom in molecular rotation and elasticity.

[0018] -Method of manufacturing plastic components for tires- The method for producing a tire resin member according to the first embodiment includes a molding step of molding a tire resin member containing at least one of a thermoplastic elastomer and a thermoplastic resin, and an electron beam irradiation step of irradiating the resin with an electron beam at least either before, after, or during the molding step.

[0019] The method for producing a tire resin member according to the first embodiment particularly includes an electron beam irradiation step. This tends to facilitate the promotion of crosslinking of the resin. Therefore, the crosslink density of the resin tends to be improved, and the molecular weight of the resin tends to be increased. As a result, it is considered that a tire including the tire resin member has better durability (particularly crack resistance).

[0020] ≪Molding process≫ The method for producing a tire resin member according to the first embodiment includes a molding step. In the molding step, a tire resin member containing at least one of a thermoplastic elastomer and a thermoplastic resin is molded. The molding step may be a step of molding a tire resin member containing additives such as compounding agents in addition to the thermoplastic elastomer and the thermoplastic resin.

[0021] In addition, the total content of the thermoplastic elastomer and the thermoplastic resin in all the resins contained in the tire resin component is preferably 50 mass% or more, more preferably 80 mass% or more, and even more preferably 90 mass% or more, and may be 100 mass%.

[0022] [Thermoplastic elastomer] The thermoplastic elastomer is not particularly limited, and any known material can be used. Examples of the thermoplastic elastomer include polyurethane thermoplastic elastomers, polyamide thermoplastic elastomers, polystyrene thermoplastic elastomers, polyester thermoplastic elastomers, olefin thermoplastic elastomers, and vinyl chloride thermoplastic elastomers.

[0023] Among the above, the thermoplastic elastomer preferably contains a crosslinked thermoplastic elastomer in which the crosslinking reaction is easily promoted by irradiation with electron beams. The thermoplastic elastomer more preferably contains at least one selected from the group consisting of vinyl chloride thermoplastic elastomers, polyester thermoplastic elastomers, polyamide thermoplastic elastomers, and olefin thermoplastic elastomers. The thermoplastic elastomer more preferably contains at least one selected from the group consisting of an olefin-based thermoplastic elastomer, a vinyl chloride-based thermoplastic elastomer, and a polyester-based thermoplastic elastomer, and particularly preferably contains a polyester-based thermoplastic elastomer.

[0024] The thermoplastic elastomers may be used alone or in combination of two or more kinds.

[0025] (Polyurethane-based thermoplastic elastomer) Examples of polyurethane-based thermoplastic elastomers include materials in which at least polyurethane forms hard segments that form pseudo-crosslinks through physical aggregation, and other polymers form soft segments that are amorphous and have a low glass transition temperature. Specific examples of polyurethane-based thermoplastic elastomers include polyurethane-based thermoplastic elastomers (TPU) as defined in JIS K6418: 2007. The polyurethane-based thermoplastic elastomer can be expressed as a copolymer including a soft segment containing a unit structure represented by the following formula A and a hard segment containing a unit structure represented by the following formula B.

[0026] [ka] [In the formula, P represents a long-chain aliphatic polyether or a long-chain aliphatic polyester. R represents an aliphatic hydrocarbon, an alicyclic hydrocarbon, or an aromatic hydrocarbon. P' represents a short-chain aliphatic hydrocarbon, an alicyclic hydrocarbon, or an aromatic hydrocarbon.]

[0027] In formula A, the long-chain aliphatic polyether or long-chain aliphatic polyester represented by P may have a molecular weight of, for example, 500 to 5000. P is derived from a diol compound containing the long-chain aliphatic polyether or long-chain aliphatic polyester represented by P. Examples of such diol compounds include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, poly(butylene adipate)diol, poly-ε-caprolactone diol, poly(hexamethylene carbonate)diol, and ABA triblock polyether, each of which has a molecular weight within the above range. These may be used alone or in combination of two or more.

[0028] In formula A and formula B, R is a partial structure introduced by using a diisocyanate compound containing an aliphatic hydrocarbon, an alicyclic hydrocarbon, or an aromatic hydrocarbon represented by R. Examples of the aliphatic diisocyanate compound containing an aliphatic hydrocarbon represented by R include 1,2-ethylene diisocyanate, 1,3-propylene diisocyanate, 1,4-butane diisocyanate, and 1,6-hexamethylene diisocyanate. In addition, examples of the diisocyanate compound containing an alicyclic hydrocarbon represented by R include 1,4-cyclohexane diisocyanate, 4,4-cyclohexane diisocyanate, etc. Furthermore, examples of the aromatic diisocyanate compound containing an aromatic hydrocarbon represented by R include 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, etc. These may be used alone or in combination of two or more.

[0029] In formula B, the short chain aliphatic hydrocarbon, alicyclic hydrocarbon, or aromatic hydrocarbon represented by P' may have a molecular weight of less than 500. P' is derived from a diol compound containing a short chain aliphatic hydrocarbon, alicyclic hydrocarbon, or aromatic hydrocarbon represented by P'. Examples of the aliphatic diol compound containing a short chain aliphatic hydrocarbon represented by P' include glycol and polyalkylene glycol, and specific examples thereof include ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol. Examples of alicyclic diol compounds containing an alicyclic hydrocarbon represented by P' include cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,3-diol, cyclohexane-1,4-diol, and cyclohexane-1,4-dimethanol. Furthermore, examples of aromatic diol compounds containing an aromatic hydrocarbon represented by P' include hydroquinone, resorcinol, chlorohydroquinone, bromohydroquinone, methylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenylmethane, bisphenol A, 1,1-di(4-hydroxyphenyl)cyclohexane, 1,2-bis(4-hydroxyphenoxy)ethane, 1,4-dihydroxynaphthalene, and 2,6-dihydroxynaphthalene. These may be used alone or in combination of two or more.

[0030] From the viewpoint of melt moldability, the number average molecular weight of the polymer (polyurethane) forming the hard segment is preferably 300 to 1500. From the viewpoint of flexibility and thermal stability of the polyurethane-based thermoplastic elastomer, the number average molecular weight of the polymer forming the soft segment is preferably 500 to 20000, more preferably 500 to 5000, and particularly preferably 500 to 3000. From the viewpoint of moldability, the mass ratio (x:y) of the hard segment (x) and the soft segment (y) is preferably 15:85 to 90:10, and more preferably 30:70 to 90:10.

[0031] The polyurethane-based thermoplastic elastomer can be synthesized by copolymerizing a polymer forming a hard segment and a polymer forming a soft segment by a known method. For example, the thermoplastic polyurethane described in JP-A-5-331256 can be used as the polyurethane-based thermoplastic elastomer. Specifically, the polyurethane-based thermoplastic elastomer is preferably a combination of a hard segment made of an aromatic diol and an aromatic diisocyanate with a soft segment made of a polycarbonate ester. More specifically, tolylene diisocyanate (TDI) / polyester-based polyol copolymer, TDI / polyether-based polyol copolymer, TDI / caprolactone-based polyol copolymer, TDI / polycarbonate-based polyol copolymer, 4,4'-diphenylmethane diisocyanate (MDI) / polyester-based polyol copolymer, MDI / At least one selected from polyether-based polyol copolymers, MDI / caprolactone-based polyol copolymers, MDI / polycarbonate-based polyol copolymers, and MDI+hydroquinone / polyhexamethylene carbonate copolymers is preferred, and at least one selected from TDI / polyester-based polyol copolymers, TDI / polyether-based polyol copolymers, MDI / polyester polyol copolymers, MDI / polyether-based polyol copolymers, and MDI+hydroquinone / polyhexamethylene carbonate copolymers is more preferred.

[0032] In addition, examples of commercially available polyurethane thermoplastic elastomers that can be used include the "Elastollan" series manufactured by BASF (e.g., ET680, ET880, ET690, ET890, etc.), the "Kuramilon U" series manufactured by Kuraray Co., Ltd. (e.g., 2000 series, 3000 series, 8000 series, 9000 series, etc.), and the "Miractran" series manufactured by Nippon Miractoran Co., Ltd. (e.g., XN-2001, XN-2004, P390RSUP, P480RSUI, P26MRNAT, E490, E590, P890, etc.).

[0033] (Polyamide thermoplastic elastomer) A polyamide-based thermoplastic elastomer is a thermoplastic resin material made of a copolymer having a polymer that forms a crystalline hard segment with a high melting point and a polymer that forms an amorphous soft segment with a low glass transition temperature, and has an amide bond (-CONH-) in the main chain of the polymer that forms the hard segment.

[0034] Examples of the polyamide-based thermoplastic elastomer include materials in which at least polyamide forms a crystalline hard segment with a high melting point, and other polymers (e.g., polyester, polyether, etc.) form amorphous soft segments with a low glass transition temperature. The polyamide-based thermoplastic elastomer may be formed using a chain extender such as dicarboxylic acid in addition to the hard segment and soft segment. Specific examples of the polyamide-based thermoplastic elastomer include thermoplastic amide elastomers (TPA) as defined in JIS K6418:2007 and polyamide-based elastomers as described in JP-A-2004-346273.

[0035] In the polyamide-based thermoplastic elastomer, examples of the polyamide that forms the hard segment include polyamides produced from monomers represented by the following general formula (1) or (2).

[0036] [ka] General formula (1) [In general formula (1), R 1 represents a molecular chain of a hydrocarbon having 2 to 20 carbon atoms (for example, an alkylene group having 2 to 20 carbon atoms).

[0037] [ka] General formula (2) [In general formula (2), R 2 represents a molecular chain of a hydrocarbon having 3 to 20 carbon atoms (for example, an alkylene group having 3 to 20 carbon atoms).

[0038] In general formula (1), R 1 As the alkylene group, a molecular chain of a hydrocarbon having 3 to 18 carbon atoms (for example, an alkylene group having 3 to 18 carbon atoms) is preferable, a molecular chain of a hydrocarbon having 4 to 15 carbon atoms (for example, an alkylene group having 4 to 15 carbon atoms) is more preferable, and a molecular chain of a hydrocarbon having 10 to 15 carbon atoms (for example, an alkylene group having 10 to 15 carbon atoms) is particularly preferable. In addition, in the general formula (2), R 2 As the alkylene group, a molecular chain of a hydrocarbon having 3 to 18 carbon atoms (for example, an alkylene group having 3 to 18 carbon atoms) is preferable, a molecular chain of a hydrocarbon having 4 to 15 carbon atoms (for example, an alkylene group having 4 to 15 carbon atoms) is more preferable, and a molecular chain of a hydrocarbon having 10 to 15 carbon atoms (for example, an alkylene group having 10 to 15 carbon atoms) is particularly preferable. Examples of the monomer represented by formula (1) or (2) include ω-aminocarboxylic acids and lactams, and examples of the polyamide forming the hard segment include polycondensates of these ω-aminocarboxylic acids or lactams, and co-condensation polymers of diamines and dicarboxylic acids.

[0039] Examples of the ω-aminocarboxylic acid include aliphatic ω-aminocarboxylic acids having 5 to 20 carbon atoms, such as 6-aminocaproic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 10-aminocapric acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. Examples of the lactam include aliphatic lactams having 5 to 20 carbon atoms, such as lauryllactam, ε-caprolactam, undecanelactam, ω-enantholactam, and 2-pyrrolidone. Examples of the diamine include diamine compounds such as aliphatic diamines having 2 to 20 carbon atoms, such as ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 3-methylpentamethylenediamine, and metaxylenediamine. Dicarboxylic acids are also represented by the formula HOOC-(R 3 ) m -COOH(R 3 m: a hydrocarbon molecular chain having 3 to 20 carbon atoms, and m: 0 or 1). Examples of the dicarboxylic acid include aliphatic dicarboxylic acids having 2 to 20 carbon atoms, such as oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid. As the polyamide forming the hard segment, a polyamide obtained by ring-opening polycondensation of lauryllactam, ε-caprolactam, or udecanlactam can be preferably used.

[0040] Examples of the polymer forming the soft segment include polyester and polyether, specifically, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, ABA triblock polyether, etc. These can be used alone or in combination of two or more. Polyether diamines obtained by reacting ammonia or the like with the terminal of polyether can also be used. Here, the term "ABA triblock polyether" refers to a polyether represented by the following general formula (3).

[0041] [ka] General formula (3) [In the general formula (3), x and z represent integers of 1 to 20. y represents an integer of 4 to 50.]

[0042] In general formula (3), x and z are each preferably an integer of 1 to 18, more preferably an integer of 1 to 16, still more preferably an integer of 1 to 14, and particularly preferably an integer of 1 to 12. In addition, in general formula (3), y is preferably an integer of 5 to 45, more preferably an integer of 6 to 40, still more preferably an integer of 7 to 35, and particularly preferably an integer of 8 to 30.

[0043] As the combination of hard segment and soft segment, the combination of each of the hard segment and soft segment mentioned above can be mentioned.Among these, as the combination of hard segment and soft segment, the combination of lauryl lactam ring-opening polycondensate and polyethylene glycol, the combination of lauryl lactam ring-opening polycondensate and polypropylene glycol, the combination of lauryl lactam ring-opening polycondensate and polytetramethylene ether glycol, or the combination of lauryl lactam ring-opening polycondensate and ABA triblock polyether is preferred, and the combination of lauryl lactam ring-opening polycondensate and ABA triblock polyether is more preferred.

[0044] From the viewpoint of melt moldability, the number average molecular weight of the polymer (polyamide) forming the hard segment is preferably 300 to 15000. From the viewpoint of toughness and low-temperature flexibility, the number average molecular weight of the polymer forming the soft segment is preferably 200 to 6000. Furthermore, from the viewpoint of moldability, the mass ratio (x:y) of the hard segment (x) and the soft segment (y) is preferably 50:50 to 90:10, more preferably 50:50 to 80:20.

[0045] The polyamide-based thermoplastic elastomer can be synthesized by copolymerizing a polymer forming a hard segment and a polymer forming a soft segment by a known method.

[0046] Examples of commercially available polyamide thermoplastic elastomers that can be used include the "UBESTA XPA" series from Ube Industries, Ltd. (e.g., XPA9063X1, XPA9055X1, XPA9048X2, XPA9048X1, XPA9040X1, XPA9040X2XPA9044, etc.) and the "VESTAMID" series from Daicel-Eponic, Ltd. (e.g., E40-S3, E47-S1, E47-S3, E55-S1, E55-S3, EX9200, E50-R2, etc.).

[0047] Polyamide-based thermoplastic elastomers are suitable as resin materials because they meet the performance requirements for a tire frame in terms of elastic modulus (flexibility), strength, etc. In addition, polyamide-based thermoplastic elastomers often have good adhesion to thermoplastic resins and thermoplastic elastomers.

[0048] (Polystyrene-based thermoplastic elastomer) Examples of polystyrene-based thermoplastic elastomers include materials in which at least polystyrene forms hard segments, and other polymers (e.g., polybutadiene, polyisoprene, polyethylene, hydrogenated polybutadiene, hydrogenated polyisoprene, etc.) form amorphous soft segments with low glass transition temperatures. As polystyrenes forming hard segments, those obtained by known radical polymerization methods, ionic polymerization methods, etc. are preferably used, and specifically, polystyrenes having anionic living polymerization are exemplified. In addition, examples of polymers forming soft segments include polybutadiene, polyisoprene, poly(2,3-dimethyl-butadiene), etc.

[0049] The combination of the hard segment and the soft segment may be any of the combinations of the hard segment and the soft segment listed above. Among these, the combination of the hard segment and the soft segment is preferably a combination of polystyrene and polybutadiene, or a combination of polystyrene and polyisoprene. In addition, in order to suppress unintended crosslinking reaction of the thermoplastic elastomer, it is preferable that the soft segment is hydrogenated.

[0050] The number average molecular weight of the polymer (polystyrene) forming the hard segment is preferably 5,000 to 500,000, and more preferably 10,000 to 200,000. The number average molecular weight of the polymer forming the soft segment is preferably 5,000 to 1,000,000, more preferably 10,000 to 800,000, and even more preferably 30,000 to 500,000. From the viewpoint of moldability, the volume ratio (x:y) of the hard segment (x) to the soft segment (y) is preferably 5:95 to 80:20, and more preferably 10:90 to 70:30.

[0051] The polystyrene-based thermoplastic elastomer can be synthesized by copolymerizing a polymer forming a hard segment and a polymer forming a soft segment by a known method. Examples of polystyrene-based thermoplastic elastomers include styrene-butadiene-based copolymers [SBS (polystyrene-poly(butylene) block-polystyrene), SEBS (polystyrene-poly(ethylene / butylene) block-polystyrene)], styrene-isoprene copolymers (polystyrene-polyisoprene block-polystyrene), styrene-propylene-based copolymers [SEP (polystyrene-(ethylene / propylene) block), SEPS (polystyrene-poly(ethylene / propylene) block-polystyrene), SEEPS (polystyrene-poly(ethylene-ethylene / propylene) block-polystyrene), SEB (polystyrene (ethylene / butylene) block)], and the like.

[0052] Examples of commercially available polystyrene-based thermoplastic elastomers that can be used include the "Tuftec" series manufactured by Asahi Kasei Corporation (e.g., H1031, H1041, H1043, H1051, H1052, H1053, H1062, H1082, H1141, H1221, H1272, etc.), the "SEBS" series manufactured by Kuraray Co., Ltd. (8007, 8076, etc.), and the "SEPS" series (2002, 2063, etc.).

[0053] (Polyester-based thermoplastic elastomer) Examples of polyester-based thermoplastic elastomers include materials in which at least a polyester forms a crystalline hard segment with a high melting point, and another polymer (e.g., polyester or polyether) forms an amorphous soft segment with a low glass transition temperature.

[0054] As the polyester forming the hard segment, an aromatic polyester can be used. The aromatic polyester can be formed, for example, from an aromatic dicarboxylic acid or an ester-forming derivative thereof and an aliphatic diol. The aromatic polyester is preferably polybutylene terephthalate derived from at least one of terephthalic acid and dimethyl terephthalate and 1,4-butanediol. The aromatic polyester can be formed, for example, from a dicarboxylic acid component such as isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, diphenoxyethanedicarboxylic acid, 5-sulfoisophthalic acid, or an ester-forming derivative thereof, and a diol having a molecular weight of 300 or less (for example, an aliphatic diol such as ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, or decamethylene glycol; 1,4-cyclohexane dimethacrylate, etc.). The polyester may be a polyester derived from a diol component such as alicyclic diols such as ethanol and tricyclodecane dimethylol; aromatic diols such as xylylene glycol, bis(p-hydroxy)diphenyl, bis(p-hydroxyphenyl)propane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane, bis[4-(2-hydroxy)phenyl]sulfone, 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 4,4'-dihydroxy-p-terphenyl, and 4,4'-dihydroxy-p-quaterphenyl; or the like. Alternatively, the polyester may be a copolymerized polyester obtained by combining two or more of these dicarboxylic acid components and diol components. It is also possible to copolymerize a polyfunctional carboxylic acid component, a polyfunctional oxyacid component, a polyfunctional hydroxy component, or the like having three or more functionalities in a range of 5 mol % or less. Examples of polyesters forming the hard segment include polyethylene terephthalate, polybutylene terephthalate, polymethylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate, with polybutylene terephthalate being preferred.

[0055] Examples of the polymer that forms the soft segment include aliphatic polyesters and aliphatic polyethers. Examples of aliphatic polyethers include poly(ethylene oxide) glycol, poly(propylene oxide) glycol, poly(tetramethylene oxide) glycol, poly(hexamethylene oxide) glycol, copolymers of ethylene oxide and propylene oxide, ethylene oxide addition polymers of poly(propylene oxide) glycol, and copolymers of ethylene oxide and tetrahydrofuran. Examples of the aliphatic polyester include poly(ε-caprolactone), polyenantholactone, polycaprylolactone, polybutylene adipate, and polyethylene adipate. Among these aliphatic polyethers and aliphatic polyesters, from the viewpoint of the elastic properties of the resulting polyester block copolymer, preferred polymers for forming soft segments include poly(tetramethylene oxide) glycol, an ethylene oxide adduct of poly(propylene oxide) glycol, poly(ε-caprolactone), polybutylene adipate, and polyethylene adipate.

[0056] From the viewpoints of toughness and low-temperature flexibility, the number average molecular weight of the polymer forming the soft segment is preferably 300 to 6000. From the viewpoint of moldability, the mass ratio (x:y) of the hard segment (x) to the soft segment (y) is preferably 99:1 to 20:80, and more preferably 98:2 to 30:70.

[0057] The combination of the hard segment and the soft segment may be, for example, the combination of the hard segment and the soft segment described above. Among these, the combination of the hard segment and the soft segment described above is preferably a combination in which the hard segment is polybutylene terephthalate and the soft segment is an aliphatic polyether, and more preferably a combination in which the hard segment is polybutylene terephthalate and the soft segment is poly(ethylene oxide) glycol.

[0058] Examples of commercially available polyester thermoplastic elastomers that can be used include the "Hytrel" series (e.g., 3046, 5557, 6347, 4047N, 4767N, etc.) manufactured by DuPont-Toray Co., Ltd. and the "Pelprene" series (e.g., P30B, P40B, P40H, P55B, P70B, P150B, P280B, E450B, P150M, S1001, S2001, S5001, S6001, S9001, etc.) manufactured by Toyobo Co., Ltd.

[0059] The polyester-based thermoplastic elastomer can be synthesized by copolymerizing a polymer forming a hard segment and a polymer forming a soft segment by a known method.

[0060] (Olefin-based thermoplastic elastomer) Examples of olefin-based thermoplastic elastomers include materials in which at least a polyolefin forms a crystalline hard segment with a high melting point, and another polymer (e.g., another polyolefin, a polyvinyl compound, etc.) forms an amorphous soft segment with a low glass transition temperature. Examples of polyolefins that form hard segments include polyethylene, polypropylene, isotactic polypropylene, polybutene, etc. Examples of olefin-based thermoplastic elastomers include olefin-α-olefin random copolymers and olefin block copolymers. Specific examples of such copolymers include propylene block copolymers, ethylene-propylene copolymers, propylene-1-hexene copolymers, propylene-4-methyl-1-pentene copolymers, propylene-1-butene copolymers, ethylene-1-hexene copolymers, ethylene-4-methyl-pentene copolymers, ethylene-1-butene copolymers, 1-butene-1-hexene copolymers, 1-butene-4-methyl-pentene, ethylene-methacrylic acid copolymers, and ethylene-methyl methacrylate copolymers. Examples of the copolymer include ethylene-ethyl methacrylate copolymer, ethylene-butyl methacrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, propylene-methacrylic acid copolymer, propylene-methyl methacrylate copolymer, propylene-ethyl methacrylate copolymer, propylene-butyl methacrylate copolymer, propylene-methyl acrylate copolymer, propylene-ethyl acrylate copolymer, propylene-butyl acrylate copolymer, ethylene-vinyl acetate copolymer, and propylene-vinyl acetate copolymer.

[0061] Among these, examples of olefin-based thermoplastic elastomers include propylene block copolymers, ethylene-propylene copolymers, propylene-1-hexene copolymers, propylene-4-methyl-1-pentene copolymers, propylene-1-butene copolymers, ethylene-1-hexene copolymers, ethylene-4-methyl-pentene copolymers, ethylene-1-butene copolymers, ethylene-methacrylic acid copolymers, ethylene-methyl methacrylate copolymers, ethylene-ethyl methacrylate copolymers, ethylene-butyl methacrylate copolymers, ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate copolymers, ethylene-butyl acrylate copolymers, propylene-methacrylic acid copolymers, propylene-propylene ... At least one selected from the group consisting of a pyrene-methyl methacrylate copolymer, a propylene-ethyl methacrylate copolymer, a propylene-butyl methacrylate copolymer, a propylene-methyl acrylate copolymer, a propylene-ethyl acrylate copolymer, a propylene-butyl acrylate copolymer, an ethylene-vinyl acetate copolymer, and a propylene-vinyl acetate copolymer is preferred, and at least one selected from the group consisting of an ethylene-propylene copolymer, a propylene-1-butene copolymer, an ethylene-1-butene copolymer, an ethylene-methyl methacrylate copolymer, an ethylene-methyl acrylate copolymer, an ethylene-ethyl acrylate copolymer, and an ethylene-butyl acrylate copolymer is more preferred. Two or more olefin resins may be used in combination, such as ethylene and propylene. The content of the olefin resin in the olefin-based thermoplastic elastomer is preferably 50% by mass or more and 100% by mass or less.

[0062] The number average molecular weight of the olefin-based thermoplastic elastomer is preferably 5000 to 10,000,000. When the number average molecular weight of the olefin-based thermoplastic elastomer is 5000 to 10,000,000, the mechanical properties of the thermoplastic resin material are sufficient and the processability is also excellent. From the same viewpoint, the number average molecular weight of the olefin-based thermoplastic elastomer is more preferably 7000 to 1,000,000, and particularly preferably 10,000 to 1,000,000. This can further improve the mechanical properties and processability of the thermoplastic resin material. In addition, the number average molecular weight of the polymer forming the soft segment is preferably 200 to 6000 from the viewpoint of toughness and low-temperature flexibility. Furthermore, the mass ratio (x:y) of the hard segment (x) and the soft segment (y) is preferably 50:50 to 95:5, and more preferably 50:50 to 90:10, from the viewpoint of moldability. The olefin-based thermoplastic elastomer can be synthesized by copolymerization using a known method.

[0063] The olefin-based thermoplastic elastomer may be an olefin-based thermoplastic elastomer modified with an acid. The term "an olefin thermoplastic elastomer modified with an acid" refers to bonding an unsaturated compound having an acidic group such as a carboxylic acid group, a sulfuric acid group or a phosphoric acid group to an olefin thermoplastic elastomer. An example of bonding an unsaturated compound having an acidic group such as a carboxylic acid group, a sulfuric acid group, or a phosphoric acid group to an olefin-based thermoplastic elastomer is to bond (e.g., graft polymerize) the unsaturated bond site of an unsaturated carboxylic acid (generally, maleic anhydride) as an unsaturated compound having an acidic group to the olefin-based thermoplastic elastomer. From the viewpoint of suppressing deterioration of the olefin-based thermoplastic elastomer, the unsaturated compound having an acidic group is preferably an unsaturated compound having a carboxylic acid group, which is a weak acid group, such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, and maleic acid.

[0064] Commercially available olefin-based thermoplastic elastomers include, for example, the "Toughmer" series manufactured by Mitsui Chemicals, Inc. (e.g., A0550S, A1050S, A4050S, A1070S, A4070S, A35070S, A1085S, A4085S, A7090, A70090, MH7007, MH7010, XM-7070, XM-7080, BL4000, BL2481, BL3110, BL3450, P -0275, P-0375, P-0775, P-0180, P-0280, P-0480, P-0680, etc.), "Nucrel" series manufactured by Mitsui DuPont Polychemical Co., Ltd. (e.g. AN4214C, AN4225C, AN42115C, N0903HC, N0908C, AN42012C, N410, N1050H, N1108C, N1110H, N1207C, N1214, AN4221C, N15 25, N1560, N0200H, AN4228C, AN4213C, N035C), "Elbaloy AC" series (e.g., 1125AC, 1209AC, 1218AC, 1609AC, 1820AC, 1913AC, 2112AC, 2116AC, 2615AC, 2715AC, 3117AC, 3427AC, 3717AC, etc.), Sumitomo Chemical Co., Ltd.'s "Acryft" series, "Ebatate" series etc., the "Ultrathene" series manufactured by Tosoh Corporation, and the "Prime TPO" series manufactured by Prime Polymer (e.g., E-2900H, F-3900H, E-2900, F-3900, J-5900, E-2910, F-3910, J-5910, E-2710, F-3710, J-5910, E-2740, F-3740, R110MP, R110E, T310E, M142E, etc.), can also be used.

[0065] (Vinyl chloride thermoplastic elastomer) Examples of vinyl chloride-based thermoplastic elastomers include materials that form hard segments made of at least crystalline polyvinyl chloride having a high melting point, and other polymers (e.g., polyolefins, polyvinyl compounds, etc.) that form amorphous soft segments with a low glass transition temperature.

[0066] The vinyl chloride-based thermoplastic elastomer refers to a thermoplastic resin material composed of a copolymer having a polymer that forms a crystalline hard segment with a high melting point and a polymer that forms an amorphous soft segment with a low glass transition temperature, and has polyvinyl chloride in the main chain of the polymer that forms the hard segment.

[0067] Examples of vinyl chloride-based thermoplastic elastomers include block copolymers, random copolymers, graft copolymers, etc., of a hard segment made of polyvinyl chloride and a soft segment made of polyvinyl chloride; and block copolymers, random copolymers, graft copolymers, etc., of a hard segment made of polyvinyl chloride and a soft segment made of other polymers (e.g., polyolefins, polyvinyl compounds, etc.).

[0068] The content of polyvinyl chloride in the vinyl chloride-based thermoplastic elastomer is preferably 50% by mass or more and 100% by mass or less.

[0069] The number average molecular weight of the vinyl chloride-based thermoplastic elastomer is preferably 5000 to 10,000,000. When the number average molecular weight of the vinyl chloride-based thermoplastic elastomer is 5000 to 10,000,000, the vinyl chloride-based thermoplastic elastomer has sufficient mechanical properties and excellent processability when used as a tire resin member. From the same viewpoint, the number average molecular weight of the vinyl chloride-based thermoplastic elastomer is more preferably 7000 to 1,000,000, and particularly preferably 10,000 to 1,000,000. This can further improve the mechanical properties and processability when used as a tire resin member. In addition, the number average molecular weight of the polymer forming the soft segment is preferably 200 to 6000 from the viewpoint of toughness and low-temperature flexibility. Furthermore, the mass ratio (x:y) of the hard segment (x) and the soft segment (y) is preferably 50:50 to 95:15, and more preferably 50:50 to 90:10, from the viewpoint of moldability. The vinyl chloride thermoplastic elastomer can be synthesized by copolymerization using a known method.

[0070] Commercially available vinyl chloride thermoplastic elastomers include, for example, the "Sunprene" series manufactured by Mitsui Chemicals, Inc., and Rheomer G and LCS manufactured by Plus Tech Co., Ltd.

[0071] [Thermoplastic resin] The thermoplastic resin is not particularly limited, and known materials can be used. Examples of the thermoplastic resin include polyester thermoplastic resin, polyamide thermoplastic resin, olefin thermoplastic resin, vinyl chloride thermoplastic resin, polyurethane thermoplastic resin, and polystyrene thermoplastic resin.

[0072] Among the above, the thermoplastic resin preferably contains a crosslinked thermoplastic resin in which the crosslinking reaction is easily promoted by irradiation with an electron beam. The thermoplastic resin more preferably contains at least one selected from the group consisting of vinyl chloride thermoplastic resins, polyester thermoplastic resins, polyamide thermoplastic resins, and olefin thermoplastic resins. The thermoplastic resin more preferably contains at least one selected from the group consisting of olefin-based thermoplastic resins, vinyl chloride-based thermoplastic resins, and polyester-based thermoplastic resins, and particularly preferably contains a polyester-based thermoplastic resin.

[0073] The thermoplastic resins may be used alone or in combination of two or more kinds.

[0074] (Polyester thermoplastic resin) The polyester-based thermoplastic resin preferably constitutes a discontinuous phase (island regions in a sea-island structure) in contrast to the continuous phase (sea regions in a sea-island structure) of the thermoplastic elastomer. In particular, when the tire resin member contains a polyester-based thermoplastic elastomer and a polyester-based thermoplastic resin, the two tend to have excellent compatibility, and the thermoplastic resin tends to have excellent dispersibility in the continuous phase of the thermoplastic elastomer, so that the tire formed from the polyester-based thermoplastic elastomer tends to have improved rigidity.

[0075] In addition, when the coating resin layer contains a polyester-based thermoplastic elastomer as a thermoplastic elastomer, the inclusion of a polyester-based thermoplastic resin in the coating resin layer means that the coating resin layer contains a thermoplastic resin consisting of the same structural unit as the hard segment of the polyester-based thermoplastic elastomer. In other words, this indicates that the ratio of the hard segment in the coating resin layer (hereinafter also referred to as the "HS ratio") increases. In this way, it is believed that the rigidity of the coating resin layer is further increased by increasing the ratio of the hard segment in the coating resin layer.

[0076] The polyester-based thermoplastic resins may be used alone or in combination of two or more kinds.

[0077] Examples of polyester-based thermoplastic resins include aliphatic polyesters such as polylactic acid, polyhydroxy-3-butylbutyrate, polyhydroxy-3-hexylbutyrate, poly(ε-caprolactone), polyenantholactone, polycaprylolactone, polybutylene adipate, and polyethylene adipate; and aromatic polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and polybutylene naphthalate (PBN). Among the above, as the polyester-based thermoplastic resin, from the viewpoint of further increasing rigidity and from the viewpoint of heat resistance and processability, aromatic polyester is preferred, polybutylene terephthalate, polyethylene terephthalate, polybutylene naphthalate, or polyethylene naphthalate is more preferred, and polybutylene terephthalate is even more preferred.

[0078] Commercially available polyester thermoplastic resins include, for example, the "Duranex" series (e.g., 201AC, 2000, 2002, etc.) manufactured by Polyplastics Co., Ltd., the "NovaDuran" series (e.g., 5010R5, 5010R3-2, etc.) manufactured by Mitsubishi Engineering Plastics Corporation, and the "Trecon" series (e.g., 1401X06, 1401X31, etc.) manufactured by Toray Industries, Inc.

[0079] (Polyamide thermoplastic resin) The polyamide-based thermoplastic resin may be the polyamide that forms the hard segment of the above-mentioned polyamide-based thermoplastic elastomer. Specific examples of polyamide-based thermoplastic resins include polyamide (amide 6) obtained by ring-opening polycondensation of ε-caprolactam, polyamide (amide 11) obtained by ring-opening polycondensation of undecane lactam, polyamide (amide 12) obtained by ring-opening polycondensation of lauryllactam, polyamide (amide 66) obtained by polycondensation of diamine and dibasic acid, and polyamide having metaxylenediamine as a constituent unit (amide MX).

[0080] The amide 6 can be, for example, {CO-(CH2)5-NH} n The amide 11 can be represented, for example, by the formula {CO-(CH2) 10 -NH} n The amide 12 can be represented, for example, by the formula {CO-(CH2) 11 -NH} n The amide 66 can be represented, for example, by {CO(CH2)4CONH(CH2)6NH} n Amide MX can be represented, for example, by the following structural formula (A-1): where n represents the number of repeating units.

[0081] [ka]

[0082] As a commercially available product of amide 6, for example, the "UBE Nylon" series (for example, 1022B, 1011FB, etc.) manufactured by Ube Industries, Ltd. can be used. As a commercially available product of amide 11, for example, the "Rilsan B" series manufactured by Arkema, Ltd. can be used. As a commercially available product of amide 12, for example, the "UBE Nylon" series (for example, 3024U, 3020U, 3014U, etc.) manufactured by Ube Industries, Ltd. can be used. As a commercially available product of amide 66, for example, the "Leona" series (for example, 1300S, 1700S, etc.) manufactured by Asahi Kasei Corporation can be used. As a commercially available product of amide MX, for example, the "MX Nylon" series (for example, S6001, S6021, S6011, etc.) manufactured by Mitsubishi Gas Chemical Co., Ltd. can be used.

[0083] The polyamide-based thermoplastic resin may be a homopolymer formed only of the above-mentioned structural units, or may be a copolymer of the above-mentioned structural units and other monomers. In the case of a copolymer, the content of the above-mentioned structural units in each polyamide-based thermoplastic resin is preferably 40% by mass or more.

[0084] (Olefin thermoplastic resin) Examples of the olefin-based thermoplastic resin include polyolefins that form the hard segments of the above-mentioned olefin-based thermoplastic elastomers. Specific examples of the olefin-based thermoplastic resin include polyethylene-based thermoplastic resins, polypropylene-based thermoplastic resins, polybutadiene-based thermoplastic resins, etc. Among these, polypropylene-based thermoplastic resins are preferred as the olefin-based thermoplastic resins in terms of heat resistance and processability. Specific examples of polypropylene-based thermoplastic resins include propylene homopolymers, propylene-α-olefin random copolymers, propylene-α-olefin block copolymers, etc. Examples of α-olefins include α-olefins having about 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.

[0085] (Vinyl chloride thermoplastic resin) The vinyl chloride thermoplastic resin may be polyvinyl chloride, which forms the hard segment of the vinyl chloride thermoplastic elastomer described above.

[0086] The vinyl chloride thermoplastic resin may be a commercially available product or a synthetic product. The vinyl chloride thermoplastic resin can be polymerized by a known method, and examples thereof include "Sunprene" manufactured by Mitsubishi Chemical Corporation and "Leonyl" manufactured by Riken Technos Corporation.

[0087] [Preferred types of thermoplastic elastomers and thermoplastic resins] Of the above, the thermoplastic elastomer and thermoplastic resin are preferably crosslinked polymers whose crosslinking reaction is easily promoted by irradiation with electron beams.

[0088] From the viewpoint of obtaining a tire resin component having superior durability (particularly crack resistance) when the tire resin component is made into a tire, it is more preferable that the thermoplastic elastomer and the thermoplastic resin include at least one selected from the group consisting of vinyl chloride thermoplastic resins, vinyl chloride thermoplastic elastomers, polyester thermoplastic elastomers, polyester thermoplastic resins, polyamide thermoplastic resins, polyamide thermoplastic elastomers, olefin thermoplastic elastomers, and olefin thermoplastic resins.

[0089] It is more preferable that the thermoplastic elastomer and thermoplastic resin include at least one selected from the group consisting of vinyl chloride thermoplastic resins, polyester thermoplastic elastomers, and olefin thermoplastic elastomers.

[0090] [Compound ingredients] The molding step may be a step of molding a tire resin member by further including a compounding agent in addition to the resin. Examples of the compounding agent include a carbodiimide compound, a polyfunctional epoxy compound, a polyfunctional amino compound, and the like. Among these, a carbodiimide compound is preferable.

[0091] (Carbodiimide compounds) The coating resin layer may contain a carbodiimide compound as a compounding agent. The carbodiimide compound has at least one carbodiimide group (-N=C=N-) in the molecule as a functional group.

[0092] The functional group equivalent of the carbodiimide compound, i.e., the density of the carbodiimide group, is preferably 100 g / eq or more and 500 g / eq or less, more preferably 100 g / eq or more and 400 g / eq or less, and even more preferably 100 g / eq or more and 300 g / eq or less. A functional group equivalent of 100 g / eq or more provides excellent low-temperature impact resistance for the coating resin layer, while a functional group equivalent of 500 g / eq or less prevents excessive thickening of the resin composition after the reaction and appropriately controls the reaction rate, enabling a uniform reaction to occur in the resin composition.

[0093] The carbodiimide compound preferably has a softening point (softening temperature) of 50° C. or more and 150° C. or less, from the viewpoints of supply stability during twin-screw kneading and compounding and ease of melt kneading with the polyester resin.

[0094] Examples of the carbodiimide compound include compounds having one or more carbodiimide groups in the molecule, which are produced from organic isocyanates (e.g., organic monoisocyanates, organic polyisocyanates (organic diisocyanates, organic triisocyanates, and other organic isocyanates having multiple isocyanate groups (-N=C=O) in the molecule)). The organic isocyanate may be an aromatic isocyanate, an aliphatic isocyanate, or a mixture thereof. The organic group of the organic isocyanate may be either an aromatic organic group or an aliphatic organic group, or may be a combination of an aromatic organic group and an aliphatic organic group. The carbodiimide compound may be synthesized, for example, by a condensation reaction of an organic polyisocyanate.

[0095] Commercially available carbodiimide compounds may be used. Examples of commercially available carbodiimide compounds include Carbodilite (registered trademark) (e.g., HMV-15CA, LA-1) manufactured by Nisshinbo Chemical Co., Ltd., and Stavaxol (registered trademark) (e.g., P, P-100, etc.) manufactured by Rhein Chemie.

[0096] [Other ingredients] The molding process may be a process for molding a tire resin member containing other components in addition to the resin and compounding agents, such as rubber, various fillers (e.g., silica, calcium carbonate, clay, etc.), antioxidants, oils, plasticizers, colorants, weather resistance agents, etc.

[0097] The tire resin component may contain the above-mentioned compounding agents, the above-mentioned other components, and the like in addition to the resin containing the thermoplastic elastomer and the thermoplastic resin. However, the content of the above-mentioned resin in the tire resin component is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more and less than 100% by mass.

[0098] [Forming method] The molding method for the tire resin member is not particularly limited as long as it is a method for molding a tire resin member containing at least one of a thermoplastic elastomer and a thermoplastic resin, and a molding method suitable for each member of the tire such as a bead member, a belt, a tire frame, etc. Examples of molding methods for the tire resin member include injection molding, extrusion molding, press molding, blow molding, insert molding, transfer molding, etc.

[0099] ≪Electron beam irradiation process≫ The method for producing a tire resin member according to the first embodiment includes an electron beam irradiation step. In the electron beam irradiation step, the resin is irradiated with an electron beam at least either before, after, or during the molding step. The inclusion of an electron beam irradiation step tends to improve the crosslink density of the resin and increase the molecular weight of the resin, which is believed to result in a tire including the tire resin member having better durability (particularly crack resistance).

[0100] The crosslinking of the resin may be any of intermolecular crosslinking, intramolecular crosslinking, and both intermolecular and intramolecular crosslinking.

[0101] The electron beam irradiation step is a step of irradiating the resin with an electron beam before, after, or during the molding step.

[0102] The electron beam irradiation process may be a process of irradiating an electron beam either before, after, or during the molding process, or a process of irradiating an electron beam both before and after the molding process, or a process of irradiating an electron beam all before, after, and during the molding process.

[0103] The electron beam irradiation step is preferably a step of irradiating with an electron beam after the molding step. When the electron beam irradiation step is a step of irradiating with electron beams after the molding step, a tire including the tire resin member tends to have better crack resistance.

[0104] The absorbed dose of the electron beam is not particularly limited as long as it is an absorbed dose that can increase the molecular weight of the resin by electron beam crosslinking. The absorbed dose of the electron beam is, for example, preferably more than 100 kGy and not more than 600 kGy, more preferably 110 kGy or more and not more than 550 kGy, and even more preferably 120 kGy or more and not more than 500 kGy.

[0105] When the absorbed dose of the electron beam exceeds 100 kGy, electron beam crosslinking tends to occur more efficiently, and a tire including the tire resin member tends to have better crack resistance. When the absorbed dose of the electron beam is 600 kGy or less, the destruction of molecular bonds in the main chain or side chain of the resin, which tends to occur in competition with electron beam crosslinking, tends to be suppressed.

[0106] The irradiation time of the electron beam is not particularly limited as long as it is a time that can increase the molecular weight of the resin by electron beam crosslinking. For example, from the viewpoint of efficiently crosslinking the resin by the electron beam and improving the crack resistance of a tire including the tire resin member, the irradiation time of the electron beam may be 1 second to 60 minutes, 1 second to 30 minutes, or 1 second to 10 minutes.

[0107] The electron beam can be irradiated using, for example, an electron beam irradiation device EPS-3000 manufactured by NHV Corporation.

[0108] The electron beam may be irradiated to the resin from one direction, or may be irradiated from multiple directions by rotating the resin using an electron beam irradiating device with a rotation function or the like.

[0109] The region to be irradiated with the electron beam is not particularly limited, and may be a region in which the electron beam is irradiated to a part of the resin, or a region in which the electron beam is irradiated to the entire region of the resin composition or resin molded article to be the tire resin component.

[0110] [Other steps] The method for producing a tire resin member according to the first embodiment may include other steps in addition to the molding step and the electron beam irradiation step. As the other steps, for example, a cutting step of cutting the resin molded body may be performed as a post-treatment step after the molding step.

[0111] -Resin components for tires- The tire resin member according to the second embodiment contains at least one resin selected from the group consisting of a thermoplastic elastomer and a thermoplastic resin, and has a gel fraction of 0.5% by mass or more. The tire resin member according to the second embodiment may contain compounding agents and other components.

[0112] The tire resin member according to the second embodiment contains at least one of a thermoplastic elastomer and a thermoplastic resin, and in particular, by setting the gel fraction within the above range, a tire including the tire resin member has excellent durability (particularly, crack resistance).

[0113] In the total resin contained in the tire resin component, the total content of the thermoplastic elastomer and the thermoplastic resin is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, and may be 100% by mass. The tire resin component may contain compounding agents, other components, and the like in addition to the resin containing the thermoplastic elastomer and the thermoplastic resin. However, the content of the resin in the tire resin component is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0114] Hereinafter, the tire resin member obtained by the method for producing a tire resin member according to the first embodiment and the tire resin member according to the second embodiment will be collectively referred to as the "tire resin member according to the present embodiment."

[0115] The tire resin member according to the present embodiment is used for, for example, a reinforcing belt member that is wound around the outer periphery of a tire frame in the circumferential direction, a bead member, a tire frame, and the like.

[0116] <Physical properties of tire resin components> The tire resin member according to the second embodiment has a gel fraction of 0.5% by mass or more, preferably 0.5% by mass or more and 100% by mass or less, more preferably 20% by mass to 80% by mass, even more preferably 20% by mass to 60% by mass, and particularly preferably 20% by mass to 55% by mass.

[0117] The gel fraction of the tire resin member being 0.5% by mass or more means that when the tire resin member is mixed with a specific solvent described below, the tire resin member contains a gel portion that remains undissolved in the solvent, i.e., a resin with a large molecular weight, and therefore tends to have excellent durability, particularly crack resistance, when used as a tire. In particular, for example, when the gel fraction of the tire resin member is 80% by mass or less, deterioration in durability due to reduced elongation when made into a tire tends to be further suppressed.

[0118] The method for setting the gel fraction of the tire resin component within the above range is not particularly limited, and examples thereof include a method of irradiating a resin with an electron beam to crosslink the resin; a method of crosslinking the resin using a crosslinking agent; a method of crosslinking the resin by irradiating it with ultraviolet light; and a method of crosslinking the resin by moisture.

[0119] The gel fraction of the tire resin member is measured as follows. (1) A test specimen is prepared by cutting a tire resin component. (2) 1 mg of the test piece is mixed and dissolved in 5 cc of HFIP (hexafluoroisopropanol), and the resulting mixture is subjected to solid-liquid separation using a filter (Tosoh Corporation, non-aqueous (H type) H-13-5, pore size φ0.5 μm). (3) The obtained filtrate is concentrated to dryness, and the mass W2 of this concentrated to dryness is measured. (4) Calculate the gel fraction (mass%) using the following formula. Gel fraction (mass%) = (W1-W2) / (W1+W2) x 100

[0120] In the case where the tire resin member contains a filler (carbon black, silica, etc.), the gel fraction means the gel fraction in the tire resin member from which the filler has been removed.

[0121] When a tire resin component contains the filler, the weight ratio of the resin to the filler such as carbon black can be analyzed by heating to 700°C under a nitrogen atmosphere. When heated to 700°C, the resin is decomposed and volatilized into monomer units and disappears regardless of the presence or absence of crosslinking. On the other hand, the filler does not show a weight loss under a nitrogen atmosphere. Using this, the resin content of the material before extraction is W1, and the resin content burned off at 700°C in the concentrated and dried product after extraction is W2, and the gel fraction can be measured from the above formula (4) in the same way as in the case of no filler.

[0122] The melt flow rate (MFR) of the tire resin component at 260°C is preferably 2.0 g / 10 min or more and 10.0 g / 10 min or less, more preferably 2.5 g / 10 min or more and 8.0 g / 10 min or less, and even more preferably 3.0 g / 10 min or more and 6.5 g / 10 min or less. When the MFR of the tire resin member is 2.0 g / 10 min or more, deterioration of molding processability tends to be suppressed, whereas when the MFR of the tire resin member is 10.0 g / 10 min or less, the tire tends to have better crack resistance.

[0123] The melt flow rate of the tire resin component is measured in accordance with JIS-K7210-1 (2014). Specifically, the melt flow rate is measured using a melt indexer (model number 2A-C, manufactured by Toyo Seiki Co., Ltd.) under the following measurement conditions: temperature 260°C, load 2.16 kg, interval 25 mm, orifice 2.09Φ×8L (mm).

[0124] The melt flow rate of the tire resin member can be controlled by the type and amount (that is, the blending ratio) of the resin.

[0125] The tensile modulus of the tire resin member is preferably 300 MPa or more and 1000 MPa or less, more preferably 400 MPa or more and 900 MPa or less, and further preferably 450 MPa or more and 800 MPa or less. When the tensile modulus of the tire resin member is 300 MPa or more, the rigidity of the tire resin member tends to be increased, whereas when the tensile modulus of the tire resin member is 1000 MPa or less, the impact resistance, particularly at low temperatures, tends to be improved.

[0126] The tensile modulus of elasticity of the tire resin member is measured in accordance with JIS K7113: 1995. Specifically, the tensile modulus of elasticity is measured using Shimadzu Autograph AGS-J (5KN) manufactured by Shimadzu Corporation, with the pulling speed set to 100 mm / min.

[0127] The tensile modulus of elasticity of the tire resin member can be controlled by the type and amount (that is, the blending ratio) of the resin.

[0128] <Resin> The resin in the tire resin member according to the second embodiment may be the same as the resin in the method for producing a tire resin member according to the first embodiment.

[0129] The thermoplastic elastomer in the tire resin member according to the second embodiment may be the same as the thermoplastic elastomer in the method for producing a tire resin member according to the first embodiment.

[0130] The thermoplastic resin in the tire resin member according to the second embodiment may be the same as the thermoplastic resin in the method for producing a tire resin member according to the first embodiment.

[0131] From the viewpoint of improving the crack resistance of a tire including the tire resin member, the resin in the tire resin member preferably contains, as a thermoplastic resin and a thermoplastic elastomer, at least one selected from the group consisting of a vinyl chloride thermoplastic resin, a vinyl chloride thermoplastic elastomer, a polyester thermoplastic elastomer, a polyester thermoplastic resin, an olefin thermoplastic elastomer, and an olefin thermoplastic resin.

[0132] Among the above, the resin in the tire resin member more preferably contains at least one selected from the group consisting of a vinyl chloride-based thermoplastic elastomer, a polyester-based thermoplastic elastomer, and an olefin-based thermoplastic elastomer, and further preferably contains a polyester-based thermoplastic elastomer.

[0133] <Combination Agents> Examples of compounding ingredients in the tire resin member according to the second embodiment include the same compounding ingredients as those in the method for producing a tire resin member according to the first embodiment.

[0134] <Other ingredients> Examples of other components in the tire resin member according to the second embodiment include the same components as those in the method for producing a tire resin member according to the first embodiment.

[0135] -Bead member and its manufacturing method- The bead member according to the second embodiment has the tire resin member according to the second embodiment. When the bead member has the tire resin member according to the second embodiment, a tire including this bead member tends to have further improved crack resistance.

[0136] The manufacturing method of the bead member according to the first embodiment includes a bead member manufacturing step of manufacturing a bead member by using the manufacturing method of the tire resin member according to the first embodiment. When the bead member manufacturing step is included, the crack resistance of a tire using the bead member manufactured by this manufacturing method tends to be further improved.

[0137] Hereinafter, the bead member obtained by the manufacturing method for a bead member according to the first embodiment and the bead member according to the second embodiment will be collectively referred to as the "bead member according to this embodiment".

[0138] The bead member according to the present embodiment may contain materials other than the tire resin member. The method for manufacturing a bead member according to this embodiment may include other steps in addition to the bead member manufacturing step.

[0139] FIG. 1 is a schematic diagram of a cross section perpendicular to the longitudinal direction of a bead wire, showing an example of a bead member according to the present embodiment. 1 includes a bead filler 103, a bead core 101, a bead wire 111, an adhesive layer 112, a first coating resin layer 113, and a second coating resin layer 114. In the bead member 110, the bead filler 103 is disposed on the tire radial direction outer side of the second coating resin layer 114. The bead member 110 may be a single member in which the bead filler 103 and the second coating resin layer 114 are integrally molded.

[0140] In the bead member, for example, the tire resin member according to the present embodiment can be applied as the bead filler 103, the adhesive layer 112, the first coating resin layer 113, and the second coating resin layer 114. In particular, when the tire resin member according to the present embodiment is used as the first coating resin layer 113 and the second coating resin layer 114, a tire including this bead member tends to have improved crack resistance.

[0141] The following is an example of a method for manufacturing a bead member in an embodiment including tire resin members as the first coating resin layer 113 and the second coating resin layer 114. For example, the method for manufacturing the bead member may include a step of forming a bead core 101, a step of forming the second coating resin layer 114, and a step of forming a bead filler 103.

[0142] Bead core 101 forming process The bead core 101 is first formed by coating the outer periphery of the bead wire 111 with an adhesive layer 112. Specifically, for example, a material (e.g., adhesive) that forms the adhesive layer 112 in a molten state is coated on the outer periphery surface of the bead wire 111. Next, the surface of the material that forms the adhesive layer 112 is further coated with a material (e.g., resin) that forms a first coating resin layer 113 in a molten state. This is then solidified by cooling to form a strip member in which the three bead wires 111 are coated with the first coating resin layer 113. Next, the strip member is wound and laminated in three layers so that the shape of the cross section perpendicular to the longitudinal direction of the bead wire is approximately rectangular. In this way, the bead core 101 is formed.

[0143] 1, the number of bead wires 111 in the bead core 101 is nine, but the bead member according to this embodiment is not limited to this, and the number of the bead wires 111 may be one or more. For example, the number of the bead wires 111 may be only one.

[0144] FIG. 1 shows an embodiment in which the strip members are stacked in three layers so that the vertical cross section has an approximately rectangular shape, but the bead member of this embodiment is not limited to this and may be stacked in one layer, two layers, or four or more layers.

[0145] In FIG. 1, the cross-sectional shape of the strip member (the cross-sectional shape perpendicular to the longitudinal direction of the bead wire 111) is approximately rectangular, but the bead member according to this embodiment is not limited to this and can have various shapes, such as approximately a parallelogram.

[0146] The adhesive layer 112 and the first coating resin layer 113 can be formed by a known method such as extrusion molding.

[0147] When stacking strip members to form the bead core 101, the method of joining the stacked strip members is not particularly limited. For example, the joining method can be a known method such as hot plate welding, in which the strip members are wound while melting the first coating resin layer 113, and the melted first coating resin layer 113 is solidified to join the strip members. Alternatively, the strip members can be joined by bonding them with an adhesive or the like.

[0148] - Second coating resin layer formation process A material (e.g., resin) that will form the second resin coating layer 114 in a molten state is coated on the surface of the bead core 101. The material is then cooled and solidified, thereby forming the second resin coating layer 114 on the surface of the bead core 101.

[0149] The second coating resin layer 114 can be formed by a known method such as injection molding. For example, when the second coating resin layer 114 is formed by injection molding, first, the bead core 101 is placed in a cavity of an injection molding die. Then, a material for forming the second coating resin layer 114 in a molten state is injected into the cavity. Next, the injected material is cooled and solidified to form the second coating resin layer 114.

[0150] ·Bead filler 103 formation process The bead filler 103 can be formed by a known method. For example, when the bead filler 103 is made of a resin, the bead filler 103 can be formed by a method such as injection molding. When the bead filler 103 is a single component integrally molded with the second coating resin layer 114, the single component can be integrally molded by a single injection using an injection molding die machined to the shape of the bead filler 103 and the second coating resin layer 114.

[0151] -Tire belt and its manufacturing method- The tire belt according to the second embodiment includes the tire resin member according to the second embodiment. When the tire belt includes the tire resin member according to the second embodiment, a tire including this tire belt tends to have further improved crack resistance.

[0152] The manufacturing method of the tire belt according to the first embodiment includes a tire belt manufacturing step of manufacturing a tire belt using the manufacturing method of the tire resin member according to the first embodiment. When the tire belt manufacturing step is included, the crack resistance of a tire using the tire belt manufactured by this manufacturing method tends to be further improved.

[0153] Hereinafter, the tire belt obtained by the manufacturing method for a tire belt according to the first embodiment and the tire belt according to the second embodiment will be collectively referred to as the "tire belt according to the present embodiment."

[0154] The tire belt according to the present embodiment may contain materials other than the tire resin members. The method for manufacturing a tire belt according to the present embodiment may include other steps in addition to the tire belt manufacturing step.

[0155] FIG. 2 is a cross-sectional view taken along the tire width direction, showing an example of the configuration of a tire including a tire belt according to this embodiment. As shown in Fig. 2, the tire 80 includes an annular skeletal member 94 including a rubber material containing rubber, a belt layer 122 (tire belt), an adhesive layer 11, and a tread 30 which is an example of a rubber member and has a groove 30A on the outer circumferential side. The skeletal member 94 refers to a portion of the tire 80 shown in Fig. 2 excluding the belt layer 122, the adhesive layer 11, and the tread 30. The skeletal member 94 includes a bead member 144, a side portion 92, and a crown portion 90, and has a carcass 86 which is present across the bead member 144, the side portion 92, and the crown portion 90. 2, the tire 80 of this embodiment is, for example, a so-called radial tire, and includes a pair of bead members 144 having bead fillers 88 embedded in the bead cores 200 and extending from the bead cores 200 toward the tire radial outer ends 88A, and a carcass 86 consisting of one carcass ply 82 having a main portion 82A and a folded-up portion 82B is straddled between one bead member 144 and the other bead member 144. Note that FIG. 2 shows the shape of the tire 80 in its natural state before it is filled with air.

[0156] 2, the belt layer 122 is configured by winding the resin-coated cord 28 spirally around the outer periphery of a skeleton member 94 in the tire circumferential direction and joining the resin-coated cord 28 to the skeleton member 94, and joining adjacent portions of the resin-coated cord 28 in the tire width direction. The resin-coated cord 28 is configured by covering a reinforcing cord 244 with a coating resin layer 266.

[0157] The reinforcing cord 244 is made of a monofilament (single wire) of metal fiber, organic fiber, or the like, or a multifilament (twisted wire) made of twisted such fibers.

[0158] Examples of the reinforcing cord 244 include a monofilament (single wire) made of one metal cord, and a multifilament (twisted wire) made of multiple twisted metal cords, with the multifilament being preferred from the viewpoint of further improving the durability of the tire. The number of multiple metal cords may be, for example, 2 to 10, and preferably 5 to 9. From the viewpoint of achieving both the internal pressure resistance and weight reduction of the tire, the thickness of the reinforcing cord 244 is preferably 0.2 mm to 2 mm, and more preferably 0.8 mm to 1.6 mm.

[0159] In the tire belt, for example, the tire resin member according to the present embodiment can be applied as the adhesive layer 11 and the coating resin layer 266. In particular, when the tire resin member according to the present embodiment is used as the coating resin layer 266, there is a tendency for the crack resistance to be further improved in the case of a tire including this tire belt.

[0160] 2, the layer of the resin-coated cord 28 is a single layer, and the reinforcing cords 244 are arranged in a row in the tire width direction, but this is not limited to the configuration. The belt layer 122 may be a laminated belt layer in which the resin-coated cord 28 is wound spirally in the tire circumferential direction to form a layer, and then another resin-coated cord 28 is wound around the outer circumferential surface of the layer.

[0161] 2 is configured by spirally winding and joining the resin-coated cord 28 to the outer peripheral surface of the skeletal member 94, but is not limited thereto. For example, the belt layer may be configured by winding a sheet in which a plurality of reinforcing cords 244 and a resin coating layer 266 are integrated into one piece, around the outer peripheral surface of the skeletal member 94.

[0162] The following is an example of a method for manufacturing a tire belt in an embodiment including a tire resin member as the coating resin layer 266. For example, the method for manufacturing a tire belt may include a step of forming a resin-coated cord and a step of forming a tire belt.

[0163] -Forming process of resin-coated cord 28 The resin-coated cord 28 is first produced by coating the outer periphery of the reinforcement cord 244 with an adhesive (not shown). Specifically, for example, the adhesive in a molten state is applied to the outer periphery surface of the reinforcement cord 244. Next, the surface of the adhesive is further coated with a material (e.g., resin) that forms the molten coating resin layer 266. This is then solidified by cooling to form the resin-coated cord 28 in which the two reinforcement cords 244 are coated with the coating resin layer 266.

[0164] 2, the number of the reinforcement cords 244 in the resin-coated cord 28 is two, but the tire belt according to the present embodiment is not limited to this, and the number of the reinforcement cords 244 may be one or more. For example, the number of the reinforcement cords 244 may be only one.

[0165] In FIG. 2, the cross-sectional shape of the resin-coated cord 28 (the cross-sectional shape perpendicular to the longitudinal direction of the reinforcement cord 244) is approximately rectangular, but the tire belt according to this embodiment is not limited to this and can have various shapes such as approximately parallelogram.

[0166] The adhesive and the coating resin layer 266 can be formed by a known method such as extrusion molding.

[0167] Formation process of the belt layer 122 The resin-coated cord 28 is fed toward the outer circumferential surface of a belt-forming drum (not shown). The resin-coated cord 28 is heated by hot air and pressed against the outer circumferential surface of the belt-forming drum in a molten state, and then cooled. In this manner, the resin-coated cord 28 is spirally wound around the outer circumferential surface of the belt-forming drum and pressed against the outer circumferential surface, thereby forming a layer of the resin-coated cord 28 on the outer circumferential surface of the belt-forming drum. Next, the belt layer 122 in which the resin-coated cord 28 is cooled and the coating resin layer 266 is solidified is removed from the belt-molding drum. Then, a composition to become the adhesive layer 11 is applied to the inner peripheral surface of the removed belt layer 122 to form a composition layer, and then the belt layer 122 is disposed radially outside the unvulcanized skeleton member 94 on the tire-molding drum. Then, the skeleton member 94 is expanded, and the outer peripheral surface of the skeleton member 94, in other words, the outer peripheral surface of the carcass 86, is pressure-bonded to the inner peripheral surface of the belt layer 122. In this manner, a layer of the resin-coated cord 28 is formed on the outer periphery of the skeleton member 94 to form the belt layer 122. If necessary, an adhesive layer may be provided between the skeleton member 94 and the belt layer 122.

[0168] -Tire frame and its manufacturing method- The tire frame body according to the second embodiment includes the tire resin member according to the second embodiment. When the tire frame body includes the tire resin member according to the second embodiment, a tire including this tire frame body tends to have further improved crack resistance.

[0169] The manufacturing method for a tire frame body according to the first embodiment includes a tire frame manufacturing step of manufacturing a tire frame body using the manufacturing method for a tire resin member according to the first embodiment. When the tire frame manufacturing step is included, the crack resistance of a tire using the tire frame body manufactured by this manufacturing method tends to be further improved.

[0170] Hereinafter, the tire frame body obtained by the tire frame body manufacturing method according to the first embodiment and the tire frame body according to the second embodiment will be collectively referred to as the "tire frame body according to this embodiment."

[0171] The tire frame body according to the present embodiment may include materials other than the tire resin members. The method for manufacturing a tire frame body according to the present embodiment may include other steps in addition to the tire frame body manufacturing step.

[0172] Fig. 3 is a perspective view showing a cross section of a portion of a tire including a tire frame according to this embodiment. Fig. 4 is a cross section of a bead member mounted on a rim. As shown in Fig. 3, the tire 10 has a cross-sectional shape substantially similar to that of a conventional pneumatic tire made of rubber.

[0173] As shown in FIG. 3, the tire 10 has a tire frame 17 consisting of a pair of bead members 12 that contact a bead seat 21 and a rim flange 22 of the rim 20, side portions 14 that extend radially outward in the tire direction from the bead members 12, and a crown portion (outer peripheral portion) 16 that connects the radially outer end of one side portion 14 to the radially outer end of the other side portion 14.

[0174] As shown in FIG. 3, the tire frame 17 is formed by facing two annular tire frame halves (tire frame pieces) 17A of the same shape, which are formed by injection molding one bead member 12, one side portion 14, and a half-width crown portion 16 as a single unit, and joining them at the tire equatorial plane.

[0175] As shown in FIG. 4, an annular bead core 18 made of steel cord is embedded in the bead member 12, as in a conventional pneumatic tire. An annular seal layer 24 made of a material having better sealing properties than the resin material constituting the tire frame 17 is formed on the portion of the bead member 12 that contacts the rim 20 or at least on the portion that contacts the rim flange 22 of the rim 20. The seal layer 24 may also be formed on the portion where the surface of the tire frame 17 (specifically, the surface of the bead member 12) contacts the bead seat 21. The seal layer 24 may be omitted if the seal between the tire frame 17 and the rim 20 can be ensured only by the resin material that forms the tire frame 17. The seal layer 24 may be any of rubber, thermoplastic resin, and thermoplastic elastomer, as long as it has a sealing property.

[0176] In the crown portion 16, a resin cord member 26 is wound spirally in the circumferential direction of the tire frame 17 as a reinforcing cord with at least a portion of the resin cord member 26 embedded in the crown portion 16 in a cross-sectional view along the axial direction of the tire frame 17. In addition, on the outer circumferential side of the resin cord member 26 in the tire radial direction, a tread 30 made of rubber, which is a material more abrasion resistant than the resin material constituting the tire frame 17, is arranged.

[0177] The tire frame 17 is formed including the tire resin member according to this embodiment. 3, the tire frame half 17A has a bilaterally symmetrical shape, that is, one tire frame half 17A and the other tire frame half 17A have the same shape. This has the advantage that only one type of mold is required to mold the tire frame half 17A.

[0178] In the tire 10, the tire frame 17 is formed of a single resin material, but the tire frame according to the present embodiment is not limited to this. For example, as long as the tire frame 17 includes the tire resin member according to the present embodiment, resin materials having different characteristics may be used for each portion of the tire frame 17 (for example, the side portion 14, the crown portion 16, the bead member 12, etc.) in the same manner as in a conventional general pneumatic tire made of rubber.

[0179] Each portion of the tire frame 17 (e.g., the side portion 14, the crown portion 16, the bead member 12, etc.) may be reinforced by burying a reinforcing material (polymeric material or metallic fiber, cord, nonwoven fabric, woven fabric, etc.).

[0180] In the tire frame, the tire resin member according to the present embodiment can be applied to, for example, portions other than the reinforcing material. In particular, when the tire resin member according to the present embodiment is used as the bead member 12, the side portion 14, and the crown portion 16, a tire including this tire frame tends to have improved crack resistance.

[0181] The following is an example of a method for manufacturing a tire frame body in an embodiment including a tire resin member as the tire frame body 17. For example, the method for manufacturing a tire frame body may include a step of forming the tire frame body.

[0182] Tire frame forming process The tire frame halves supported by the thin metal support rings are placed opposite each other. Next, a joining mold is placed so as to contact the outer circumferential surfaces of the butted portions of the tire frame halves. Here, the joining mold is configured to press the periphery of the joints (butted portions) of the tire frame halves with a predetermined pressure (not shown). Then, the periphery of the joints of the tire frame halves is pressed at a pressure equal to or higher than the melting point (or softening point) of the material forming the tire frame, that is, the resin in the tire resin member according to this embodiment. When the joints of the tire frame halves are heated and pressurized by the joining mold, the joints melt and the tire frame halves are fused together. Then, a tire frame 17 is formed in which these members are integrated.

[0183] The tire frame body 17 is formed by injection molding, but the method of forming the tire frame body according to the present embodiment is not limited to this. For example, the tire frame body 17 may be formed by vacuum forming, pressure forming, melt casting, or the like. The tire frame 17 is formed by joining multiple components (tire frame halves 17A), but the tire frame according to this embodiment is not limited to this, and two tire frames may be joined into one component by a molten core method using a low-melting point metal, a split core method, or blow molding, or three or more components may be joined into one component.

[0184] -Tire and its manufacturing method- The tire according to the second embodiment includes the tire resin member according to the second embodiment. When the tire includes the tire resin member according to the second embodiment, the crack resistance of the tire tends to be further improved.

[0185] The method for producing a tire according to the first embodiment includes a step of producing at least a part of a resin member by the method for producing a tire resin member according to the first embodiment. By including the step, the crack resistance of a tire produced by this production method tends to be further improved.

[0186] Hereinafter, the tire obtained by the tire manufacturing method according to the first embodiment and the tire according to the second embodiment will be collectively referred to as the "tire according to this embodiment."

[0187] The tire according to the present embodiment may contain materials other than the tire resin member. The tire manufacturing method according to the present embodiment may include other steps.

[0188] An example of the tire configuration according to this embodiment is the tire configuration shown in FIG. 2 of the tire belt described above.

[0189] One aspect of the present embodiment may be, for example, a method for manufacturing a tire including a tire resin member and a rubber member, the method including the molding step, the electron beam irradiation step after the molding step, and a vulcanization step of vulcanizing the rubber member after the electron beam irradiation step.

[0190] An example of a tire manufacturing method will be described below with reference to the tire 80 shown in Fig. 2. The tire manufacturing method may include, for example, a step of forming a member that will be the skeleton of the tire, a step of forming a belt on the outer periphery of the member that will be the skeleton, a step of forming a tread on the outer periphery of the belt, and a vulcanization step.

[0191] The step of forming the framework members may be a tire frame body molding step of molding a tire frame body containing a resin according to the desired tire performance.

[0192] The step of forming the belt on the outer periphery of the framework member may be a manufacturing step similar to the manufacturing step in the manufacturing method for the tire belt according to the embodiment described above.

[0193] A process of forming a tread on the outer peripheral surface of the belt A composition that will become the adhesive layer 11 is applied to the outer peripheral surface of the belt layer 122, and dried as necessary to form a composition layer. Next, a tread before vulcanization is wound around the outer peripheral surface of the composition layer. The application of the composition and the winding of the tread before vulcanization may be performed while rotating the framework member 94 on which the belt layer 122 is provided.

[0194] · Vulcanization process In the vulcanization step, for example, a framework member 94 (i.e., a raw tire) in which a belt layer 122 containing rubber, a composition layer, and a tread before vulcanization are laminated is vulcanized. Specifically, the framework member 94 is placed in a vulcanization can or mold and heated, whereby the composition layer is hardened to form an adhesive layer 11, and the tread before vulcanization is vulcanized to form a tread 30. Examples of the vulcanization temperature include 160°C to 220°C, and examples of the vulcanization time include 1 minute to 20 minutes. In this manner, the tire 80 of the present embodiment is obtained.

[0195] One embodiment of the present disclosure includes the following aspects. [1] A molding step of molding a tire resin member containing at least one resin selected from a thermoplastic elastomer and a thermoplastic resin; an electron beam irradiation step of irradiating the resin with an electron beam at least either before, after, or during the molding step; Including, A method for producing a tire resin member. [2] The electron beam irradiation step is performed after the molding step. A method for producing a tire resin member according to [1]. [3] The absorbed dose of the electron beam is more than 100 kGy and not more than 600 kGy. The method for producing a tire resin member according to [1] or [2]. [4] The thermoplastic resin and the thermoplastic elastomer are At least one selected from the group consisting of vinyl chloride thermoplastic resins, vinyl chloride thermoplastic elastomers, polyester thermoplastic elastomers, polyester thermoplastic resins, polyamide thermoplastic resins, polyamide thermoplastic elastomers, olefin thermoplastic elastomers, and olefin thermoplastic resins, The method for producing a tire resin member according to any one of [1] to [3]. [5] A method for producing a bead member, comprising: a bead member producing step of producing a bead member by using the method for producing a tire resin member according to any one of [1] to [4]. [6] A method for producing a tire belt, comprising a tire belt production step of producing a tire belt by using the method for producing a tire resin member according to any one of [1] to [4]. [7] A method for producing a tire frame body, comprising: a tire frame body production step of producing a tire frame body by using the method for producing a tire resin member according to any one of [1] to [4]. [8] A method for producing a tire, comprising a step of producing at least a part of a resin member by the method for producing a tire resin member according to any one of [1] to [4]. [9] A method for producing a tire including a tire resin member and a rubber member, comprising: The molding step; the electron beam irradiation step after the molding step; a vulcanization step of vulcanizing the rubber member after the electron beam irradiation step; The method for producing a tire according to [8], comprising:

[10] The thermoplastic elastomer and / or thermoplastic resin are included, A tire resin member having a gel fraction of 0.5% by mass or more.

[11] The gel fraction is 20% by mass to 80% by mass. The tire resin member according to

[10] .

[12] The thermoplastic resin and the thermoplastic elastomer are At least one selected from the group consisting of vinyl chloride thermoplastic resins, vinyl chloride thermoplastic elastomers, polyester thermoplastic elastomers, polyester thermoplastic resins, polyamide thermoplastic resins, polyamide thermoplastic elastomers, olefin thermoplastic elastomers, and olefin thermoplastic resins, The tire resin member according to

[10] or

[11] .

[13] A bead member having the tire resin member according to any one of

[10] to

[12] .

[14] A belt for a tire, comprising the resin member for a tire according to any one of

[10] to

[12] .

[15] A tire frame having the tire resin member according to any one of

[10] to

[12] .

[16] A tire comprising the tire resin member according to any one of

[10] to

[12] . EXAMPLES

[0196] The present disclosure will be described in more detail below using examples, but the present disclosure is not limited thereto.

[0197] -Manufacture of plastic components for tires- [Examples 1 to 3, Comparative Example 1] A mixture (resin composition forming a tire resin member) having the composition shown in Table 1 was injection molded to obtain a molded body having a thickness of 2 mm. The obtained molded body was irradiated with an electron beam at an absorbed dose shown in Table 1. Then, a dumbbell-shaped test piece (No. 7 test piece) as specified in JIS K6251:1993 was prepared from this molded body after electron beam irradiation, and this was used as the tire resin member in each example. For the tire resin member (resin layer) and adhesive layer of each example, the gel fraction was measured by the measurement method described in the above-mentioned embodiment, and the results are shown in Table 1.

[0198] <Crack growth resistance (crack growth rate: DC / DN measurement)> A 0.5 mm pre-crack was made in each test piece, and the number of times the 5 mm wide test piece was broken was measured using an electromagnetic servo pulsar manufactured by Shimadzu Corporation. The measurement conditions were temperature = 40°C, strain = 7% and 3%, and frequency = 17Hz. The higher the value, the better the crack propagation resistance. The results are shown in Table 1.

[0199] <Measurement of belt pull fatigue index> In the resin-coated cord 28 shown in Figure 2, the resin coating layer is left only for a length of 2 cm, and the remaining part is exposed as a reinforcing cord (SC). A fatigue test was conducted in which a shear force was applied between the two SCs by repeatedly pulling each SC in the opposite direction. An electromagnetic servo pulser made by Shimadzu Corporation was used to apply a constant load of 200 N at 17 Hz in an 80°C environment.

[0200] The components of the resin composition shown in Table 1 are as follows: The units of the composition of each component in the resin composition shown in Table 1 are parts by mass.

[0201] (Thermoplastic resins and thermoplastic elastomers) 5557: Toray DuPont, polyester thermoplastic elastomer, "Hytrel 5557", melting point 207°C, functional group equivalent (carboxyl group density) 4.5×10 -5 g / eq. 1401X06: Toray Industries, Inc., polybutylene terephthalate resin (PBT), "TORECON 1401X06", MFR: 22, functional group equivalent (carboxyl group density) 9.3 x 10 -5 g / eq.

[0202] (Combination Agent) · 15CA: Nisshinbo Chemical Inc., carbodiimide compound, "Carbodilite (registered trademark) HMV-15CA", functional group equivalent (density of carbodiimide group) 260g / eq, softening point 70°C.

[0203] [Table 1]

[0204] -Manufacture of tires having tire resin components as belts- Separately from the preparation of the above test specimens, a tire having the tire resin member as a belt is manufactured, and a BF drum test is carried out using the tire, as described in detail below.

[0205] (Production of resin-metal composite members including tire resin members) An adhesive layer is formed by applying the following adhesive G-1 that has been heated and melted to a multifilament having an average diameter of φ1.15 mm (a twisted wire made by twisting seven φ0.35 mm monofilaments (steel, strength: 280 N, elongation: 3%)).

[0206] Adhesive G-1: Mitsubishi Chemical Corporation, acid-modified polyester thermoplastic elastomer, "Primalloy-AP GQ741", melting point 214°C, elastic modulus 650MPa

[0207] Next, a mixture having the composition shown in Table 1 (a resin composition forming a tire resin member) extruded by an extruder is applied to the outer periphery of the adhesive layer to coat it, and then cooled. The extrusion conditions are a temperature of the metal member (i.e., the multifilament) of 240°C, a temperature of the coating resin of 260°C, and an extrusion speed of 30 m / min. The obtained molded body is irradiated with an electron beam having an absorbed dose shown in Table 1. In this manner, a resin-metal composite member is produced, which has a structure in which the outer periphery of the multifilament (metal member) is covered with a resin coating layer via an adhesive layer, and contains an electron beam crosslinked resin. The average thickness of the resin coating layer is 500 μm, and the average thickness of the adhesive layer is 100 μm.

[0208] (Tire manufacturing) A carcass is prepared in which a reinforcing cord is covered with a coating rubber containing a rubber material, and a bead member is prepared which has a bead core in which a metal wire serving as a bead wire is covered with a bead coating layer containing a rubber material, and a bead filler in contact with the bead core and containing a rubber material. Next, the obtained resin metal composite member, bead member, and carcass are used to manufacture a raw tire in which the carcass is straddled between a pair of bead members and the ends are fixed, the resin metal composite member is wound around the crown portion of the carcass, unvulcanized tread rubber is placed thereon, and unvulcanized side rubber is placed on the outer side of the carcass in the tire width direction in the side portion. The resin metal composite member is placed on the carcass so that the average distance between the metal members of adjacent resin metal composite members is 1000 μm. The tire size is 225 / 40R18. The thickness of the tread rubber is 10 mm. Then, the raw tire is heated (rubber vulcanization) at 170° C. for 18 minutes to obtain the tire in each example.

[0209] <<Drum running test>> The durability of the tires produced in each example is evaluated by the following durability test 1 or 2. The results are shown in Tables 2 and 3. Note that the results of the durability tests in Comparative Example 1 and Example 2 are data obtained by actually carrying out measurements, while the other examples are predicted data.

[0210] <Durability test 1> The prototype tire of size 225 / 40R18 that can be produced as described above is placed in a room at 25±2℃ and the internal pressure is 3.0kg / cm 2After adjusting the air pressure, leave it for 24 hours. After that, readjust the air pressure, put a load of 1010 kg on the tire, run it on a drum with a diameter of about 3 m at a speed of 60 km / h for 6000 km, and evaluate it according to the following criteria. If the evaluation result is "A" or "B", it can be said that it is suitable for use as a tire. A: No cracks or other damage is visible after driving. B: Able to complete the course, but has some damage such as cracks that do not interfere with driving. C: Cannot complete the course or has damage such as cracks that interfere with driving.

[0211] [Table 2]

[0212] <Durability test 2> The 225 / 40R18 prototype tire produced as described above is adjusted to an internal pressure of 220kPa in a room at 25±2°C, and then left for 24 hours. The air pressure is then readjusted, and a load of 645kg is placed on the tire, which is then run at a speed of 150km / h on a drum with a diameter of approximately 3m under conditions of 38°C±3°C, and evaluated according to the following criteria. If the evaluation result is "A" or "B", it can be said that the tire is suitable for use as a tire. A: Something that has traveled more than 50,000km. B: Those that have been driven more than 30,000km but less than 50,000km. C: Those that have been driven less than 30,000km.

[0213] [Table 3]

[0214] As shown in Tables 2 and 3, the tire resin members of the Examples have superior durability, particularly crack resistance, when formed into tires, compared to the tire resin members of the Comparative Examples.

[0215] The disclosure of Japanese Patent Application No. 2019-222980, filed on December 10, 2019, is incorporated herein by reference in its entirety. All publications, patent applications, and standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or standard was specifically and individually indicated to be incorporated by reference. [Explanation of symbols]

[0216] 10 Tires 11 Adhesive layer 12 Bead member 14 Side section 16 Crown section 17 Tire frame 17A Tire frame half 18 Bead core 20 Rims 21 Bead seat 22 Rim flange 24 Sealing layer 26 Resin cord material 28 Resin-coated cord 30 Tread 80 Tires 82 Carcass ply 86 Carcass 94 Skeletal components 101 Bead core 103 Bead filler 110 Bead member 111 Bead wire 112 Adhesive layer 113 First coating resin layer 114 Second coating resin layer 122 Belt layer 144 Bead member 200 Bead Core 244 Reinforcement Cord 266 Resin Coating Layer

Claims

1. The tire resin member includes at least one of a thermoplastic elastomer and a thermoplastic resin, and has a gel fraction of 0.5% by mass or more. The bead member, wherein the thermoplastic resin and the thermoplastic elastomer include at least one selected from the group consisting of vinyl chloride-based thermoplastic resins, vinyl chloride-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyester-based thermoplastic resins, and polyamide-based thermoplastic resins.

2. The tire resin member includes at least one of a thermoplastic elastomer and a thermoplastic resin, and has a gel fraction of 62.5% by mass to 80% by mass. The thermoplastic resin and the thermoplastic elastomer include at least one selected from the group consisting of vinyl chloride thermoplastic resins, vinyl chloride thermoplastic elastomers, polyester thermoplastic elastomers, polyester thermoplastic resins, and polyamide thermoplastic resins.

3. The tire resin member includes at least one of a thermoplastic elastomer and a thermoplastic resin, and has a gel fraction of 0.5% by mass or more. the thermoplastic resin and the thermoplastic elastomer include at least one selected from the group consisting of a vinyl chloride-based thermoplastic resin, a vinyl chloride-based thermoplastic elastomer, a polyester-based thermoplastic elastomer, a polyester-based thermoplastic resin, and a polyamide-based thermoplastic resin.

Images