Hydrogenated copolymer tube

Abstract

To provide a tube using a hydrogenated copolymer.SOLUTION: There is provided a tube containing a hydrogenated copolymer (a) satisfying the following (1) to (3) which is a hydrogenated copolymer (a) containing at least one polymer block A1 composed mainly of a vinyl aromatic compound and at least one polymer block A2 containing a vinyl aromatic compound and a conjugated diene compound. (1) The content of all vinyl aromatic compounds contained in the hydrogenated copolymer (a) is 30 to 90 mass% based on the mass of the hydrogenated copolymer (a). (2) The content of the polymer block A1 is 1 to 40 mass% based on the mass of the hydrogenated copolymer (a). (3) The content of the vinyl aromatic compound contained in the polymer block A2 is 25 to 80 mass% based on the mass of the polymer block A2.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a tube using a hydrogenated copolymer. [Background technology]

[0002] Hydrogenated copolymers of block copolymers consisting of conjugated diene compounds and vinyl aromatic compounds have elasticity at room temperature similar to that of natural rubber or synthetic rubber, and at high temperatures they have moldability similar to that of thermoplastic resins. Furthermore, they have excellent weather resistance and heat resistance. Therefore, they have been widely used as resin modifiers in a wide range of fields, including automobile parts, medical molded products, asphalt modifiers, footwear, molded products such as food containers, packaging materials, adhesive sheets, and home appliance and industrial parts.

[0003] Recently, due to the need to address environmental issues, the development of non-halogenated transparent polymeric materials has progressed, and soft vinyl chloride resins have been used in particular as materials for medical tubing. However, because soft vinyl chloride resins contain large amounts of plasticizers such as dioctyl phthalate, there is a problem that the plasticizer in the medical tubing elutes and contaminates the liquid flowing through the medical tubing. Therefore, in recent years, the use of styrene-based thermoplastic elastomers has been considered as an alternative to soft vinyl chloride resins, and Patent Document 1 proposes a medical resin composition that combines a hydrogenated block copolymer that meets certain conditions with an olefin-based resin.

[0004] Patent Document 1 discloses a tube comprising a styrene-based thermoplastic elastomer (a) and a polypropylene-based resin (b), in which the elastomer (a) is a hydrogenated block copolymer composed of a polymer block (A) made of an aromatic vinyl compound and a polymer block (B) made of isoprene and / or 1,3-butadiene, in which the content of the polymer block (A) before hydrogenation is 5 to 40 mass %, the hydrogenation rate of the polymer block (B) is 70% or more, and the content of 1,2-bonds and 3,4-bonds in the polymer block (B) is 30 to 85 mol %, the mass ratio [(a) / (b)] of the styrene-based thermoplastic elastomer (a) to the polypropylene resin (b) is 90 / 10 to 40 / 60, and the ratio [I(14) / I(15)] of the diffraction peak intensity at a scattering angle of 14° to the diffraction peak intensity at a scattering angle of 15° in X-ray diffraction [I(15)] is 1.4 or more. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2010 / 104068 Summary of the Invention [Problem to be solved by the invention]

[0006] Tubes used in the medical field, such as infusion tubes, are required to have properties such as transparency, flexibility, kink resistance, clampability (strain recovery), low stickiness, solvent adhesion, and radiation (gamma ray, electron beam) sterilization resistance, and furthermore, a good balance of each of these properties is required.

[0007] However, there is room for further improvement in transparency, flexibility, and kink resistance of the tube disclosed in Patent Document 1. Furthermore, Patent Document 1 does not evaluate solvent adhesion.

[0008] Medical tubing made using styrene-based thermoplastic elastomers can be strongly bonded to other plastic materials using organic solvents. In medical applications, plastic connectors are made from a variety of materials, such as polyolefin, polyester, polycarbonate, polyvinyl chloride, polyetherketone, ABS, polystyrene, polyamide, polyimide, polyoxymethylene, polyacrylate, polyurethane, or polysulfone. Connectors are welded to medical tubing using solvent-based adhesives such as tetrahydrofuran, cyclohexanone, cyclohexane, methyl ethyl ketone, and the like. If the bond strength between the medical tubing and the connector is not strong enough, the connection may become loose, leading to fluid leakage. Solvent adhesive strength can be evaluated by measuring the peel strength when separating the medical tubing from the connector. The tube molded in Patent Document 1 contains polypropylene, which prevents the tube from dissolving in solvents, resulting in low adhesive strength with the connector.

[0009] An object of the present invention is to provide a tube having excellent solvent adhesiveness. [Means for solving the problem]

[0010] As a result of intensive investigations aimed at solving the above problems, the present inventors have found that a hydrogenated copolymer having a specific structure can solve the above problems of the conventional art, and have thus completed the present invention.

[0011] That is, the present invention is as follows. [1] A tube comprising a hydrogenated copolymer (a) containing at least one polymer block A1 mainly composed of a vinyl aromatic compound and at least one polymer block A2 containing a vinyl aromatic compound and a conjugated diene compound, wherein the hydrogenated copolymer (a) satisfies the following (1) to (3): (1) The content of all vinyl aromatic compounds contained in the hydrogenated copolymer (a) is 30% by mass to 90% by mass based on the mass of the hydrogenated copolymer (a). (2) The content of the polymer block A1 is 1% by mass to 40% by mass based on the mass of the hydrogenated copolymer (a). (3) The content of the vinyl aromatic compound contained in the polymer block A2 is 25% by mass to 80% by mass based on the mass of the polymer block A2. [2] The tube according to [1], wherein the content of the polymer block A1 is 5 to 35 mass % based on the mass of the hydrogenated copolymer (a). [3] The tube according to [1] or [2], which does not contain polyolefin resin. [4] The tube according to any one of [1] to [3], which contains at least two lubricants selected from the group consisting of fatty acid amide-based lubricants, metal stearate-based lubricants, and fatty acid monoglyceride-based lubricants. [Effects of the Invention]

[0012] According to the present invention, a tube having excellent solvent adhesiveness can be provided. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 shows the relationship between temperature and loss tangent (tan δ) for hydrogenated copolymer (a-1), hydrogenated copolymer (a-2), and Tuftec (registered trademark) H1043. [Figure 2] FIG. 2 shows the relationship between temperature and storage modulus for hydrogenated copolymer (a-1), hydrogenated copolymer (a-2), and Tuftec (registered trademark) H1043. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. Note that the present invention is not limited to the following embodiment, and various modifications can be made within the scope of the gist of the present invention.

[0015] [Hydrogenated copolymer (a)] The tube of this embodiment is a tube using a hydrogenated copolymer (a) containing (preferably consisting of) a vinyl aromatic compound and a conjugated diene compound.

[0016] Each component will be described in detail below. In this specification, the term "mainly composed of" means that the target monomer unit is contained in the target polymer block in an amount of more than 70% by mass and not more than 100% by mass, preferably 80% by mass or more and 100% by mass or less, and more preferably 90% by mass or more and 100% by mass or less.

[0017] (vinyl aromatic compounds) Examples of vinyl aromatic compounds constituting the hydrogenated copolymer include, but are not limited to, styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylethylene, N,N-dimethyl-p-aminoethylstyrene, and N,N-diethyl-p-aminoethylstyrene.

[0018] Among these, styrene, α-methylstyrene, and 4-methylstyrene are preferred from the viewpoints of availability and productivity. As the vinyl aromatic compound contained in the block containing a vinyl aromatic and a conjugated diene (so-called random block), styrene is preferred from the viewpoint of reactivity. These may be used alone or in combination of two or more.

[0019] (Conjugated diene compounds) The conjugated diene compound constituting the hydrogenated copolymer is not particularly limited as long as it is a diolefin having a conjugated double bond, and examples thereof include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, and 1,3-hexadiene.

[0020] Among these, 1,3-butadiene and isoprene are preferred from the viewpoints of availability and productivity. These may be used alone or in combination of two or more.

[0021] (hydrogenation rate) In this embodiment, it is preferable that 70 mol% or more of all conjugated diene compounds in the hydrogenated copolymer (a) are hydrogenated. The hydrogenation rate also affects the solubility parameter, fluidity, and glass transition temperature of the copolymer, so a preferred hydrogenation rate is set taking these effects into consideration. More specifically, by setting the solubility parameter within a range that satisfies solvent adhesion, adjusting the fluidity within a range that exhibits the required processability, and appropriately setting the glass transition temperature, kink resistance tends to be exhibited. That is, the hydrogenation rate of all conjugated diene compound units in the hydrogenated copolymer (a) (the hydrogenation rate of carbon-carbon double bonds derived from conjugated diene units) is preferably 70 mol% or more, more preferably 85 mol% or more, and even more preferably 95 mol%. There is no particular upper limit.

[0022] A hydrogenation rate of 70 mol% or more improves the mechanical strength, heat resistance, and blocking resistance of the hydrogenated copolymer, thereby improving the tensile strength, breaking elongation, and low stickiness of the resulting tube. The hydrogenation rate can be controlled, for example, by the amount of catalyst used during hydrogenation, and the hydrogenation rate can be controlled, for example, by the amount of catalyst used during hydrogenation, the amount of hydrogen fed, the pressure, and the temperature. The hydrogenation rate can be measured by observing peaks derived from double bonds using proton nuclear magnetic resonance (H-NMR).

[0023] (Hydrogenated copolymer (a)) The hydrogenated copolymer (a) has a hydrogenated polymer block (hereinafter referred to as polymer block A2) containing (preferably consisting of) a vinyl aromatic compound and a conjugated diene compound.

[0024] Furthermore, the hydrogenated copolymer (a) has at least one block (hereinafter sometimes referred to as polymer block A1) mainly composed of a vinyl aromatic compound.

[0025] The hydrogenated copolymer (a) preferably has a structure represented by the following general formula, for example: The hydrogenated copolymer (a) may also be a mixture containing a plurality of types of the following structures in any ratio. (A1-A2)n A1-(A2-A1)n A2-(A1-A2)n [(A1-A2)n]mZ [(A2-A1)n]mZ [(A1-A2)n-A1]mZ [(A2-A1)n-A2]mZ

[0026] In each general formula representing the hydrogenated copolymer (a) above, A1 is a polymer block mainly composed of a vinyl aromatic compound, and A2 is a polymer block containing (preferably consisting of) a vinyl aromatic compound and a conjugated diene compound.

[0027] The polymer block A1 preferably has a vinyl aromatic compound content of more than 90% by mass. The polymer block A2 contains (preferably consists of) a vinyl aromatic compound and a conjugated diene compound, and has a vinyl aromatic compound content of 25 to 80% by mass. The boundary between the polymer block A1 and the polymer block A2 does not necessarily have to be clearly distinguishable.

[0028] Furthermore, n is an integer of 1 or more, preferably an integer of 1 to 5. From the viewpoint of utilizing the elastomer properties, n is preferably 1.

[0029] m is an integer of 2 or more, preferably an integer of 2 to 12, and more preferably an integer of 2 to 8.

[0030] Z represents a residue of a coupling agent. The coupling agent is not limited to the following, but examples thereof include polyhalogen compounds and acid esters, which will be described later.

[0031] When the polymer block A1 is a copolymer of a vinyl aromatic compound and another monomer unit, the vinyl aromatic compound in the polymer block A1 may be distributed uniformly or in a tapered pattern, or may have a plurality of uniformly distributed portions and / or a plurality of taperedly distributed portions. Furthermore, the polymer block A1 may have a plurality of portions with different amounts of the vinyl aromatic compound.

[0032] The vinyl aromatic compound in the polymer block A2 may be distributed uniformly or in a tapered pattern. Furthermore, the vinyl aromatic compound may have a plurality of uniformly distributed portions and / or a plurality of taperedly distributed portions. Furthermore, the polymer block A2 may have a plurality of portions with different vinyl aromatic compound contents.

[0033] <Total vinyl aromatic compound content> The total content of vinyl aromatic compounds in the hydrogenated copolymer (a) is preferably 30% by mass to 90% by mass, more preferably 35% by mass to 80% by mass, and even more preferably 40% by mass to 70% by mass.

[0034] The content of the conjugated diene compound in the hydrogenated copolymer (a) is preferably 10 to 70% by mass, more preferably 20 to 65% by mass, and even more preferably 30 to 60% by mass.

[0035] When the total content of the vinyl aromatic compounds in the hydrogenated copolymer (a) is 30% by mass or more, the resulting tube has excellent solvent adhesion.When the total content of the vinyl aromatic compounds is 90% by mass or less, the resulting tube using the hydrogenated copolymer (a) of this embodiment has excellent flexibility, transparency, and kink resistance.

[0036] The total content of vinyl aromatic compounds can be calculated from the absorption intensity at 262 nm using an ultraviolet spectrophotometer according to the method described in the Examples below.

[0037] <Content of vinyl aromatic compound in polymer block A2> The content of the vinyl aromatic compound in the hydrogenated polymer block A2 in the hydrogenated copolymer (a) is preferably 25 to 80% by mass. The upper limit of the content is more preferably 75% by mass, and even more preferably 70% by mass. The lower limit of the content is preferably 30% by mass, more preferably 35% by mass, and even more preferably 40% by mass.

[0038] When the content of the vinyl aromatic compound in the hydrogenated polymer block A2 is 25% by mass or more, the tube of the present embodiment has excellent kink resistance and solvent adhesion, and when the content of the vinyl aromatic compound is 80% by mass or less, the tube has excellent transparency and flexibility.

[0039] The content of the vinyl aromatic compound in the hydrogenated polymer block A2 can be adjusted to the above-mentioned range by adjusting the amount of the vinyl aromatic compound fed during polymerization, and can be measured by nuclear magnetic resonance (NMR) spectroscopy.

[0040] <Content of Polymer Block A1> In the hydrogenated copolymer (a), the content of the polymer block A1 mainly composed of the vinyl aromatic compound is preferably 1% by mass to 40% by mass, more preferably 5% by mass to 35% by mass, and even more preferably 10% by mass to 30% by mass, relative to the mass of the hydrogenated copolymer (a).

[0041] When the content of polymer block A in hydrogenated copolymer (a) is 1% by mass or more, the resulting tube has excellent solvent adhesion. The reason why a polymer block A1 content as low as 1% by mass affects solvent adhesion is unknown. However, based on the fact that the polymer properties are also affected when vinyl aromatic groups are unbalanced in random blocks, it has been empirically inferred that a content of 1% by mass or more affects solvent adhesion. When the content of block polymer A is 40% by mass or less, the resulting tube has excellent transparency, flexibility, and kink resistance.

[0042] The content of the polymer block A1 can be adjusted by the amount of the monomer fed.

[0043] The content of polymer block A1 in the hydrogenated copolymer (a) can be calculated using the mass of the polymer mainly composed of a vinyl aromatic compound (excluding vinyl aromatic compounds having an average degree of polymerization of about 30 or less) determined by a method of oxidatively decomposing the unhydrogenated copolymer (a') with t-butyl hydroperoxide using osmium tetroxide as a catalyst (the method described in I. M. Kolthoff, et al., Polym. Sci. 1, 429 (1946)) (hereinafter referred to as the osmium tetroxide decomposition method).

[0044] The content of polymer block A1 in the hydrogenated copolymer (a) can be measured by nuclear magnetic resonance (NMR) using the copolymer after hydrogenation (hydrogenated copolymer (a)) according to the method described in Y. Tanaka, et al., RUBBER CHEMISTRY and TECHNOLOGY 54, 685 (1981).

[0045] The NMR method will be specifically explained using an example in which the vinyl aromatic compound is styrene and the conjugated diene compound is 1,3-butadiene.

[0046] 30 mg of the hydrogenated copolymer (a) was dissolved in 1 g of deuterated chloroform, and the H-NMR was measured using the sample. The content (Ns value) of the polymer block A1 (in this case, the polystyrene block) was calculated from the ratio of the integrated value of the chemical shift from 6.9 ppm to 6.3 ppm to the total integrated value. Block styrene strength (b-St strength) = (integrated value of 6.9 ppm to 6.3 ppm) / 2 Random styrene strength (r-St strength) = (integrated value of 7.5 ppm to 6.9 ppm) - 3 × (b-St) Ethylene-butylene strength (EB strength) = Total integrated value - 3 × {(b-St intensity) + (r-St intensity)} / 8 Polystyrene block content (Ns value) obtained by NMR method =104×(b-St strength) / [104×{(b-St strength)+(r-St strength)}+56×(EB strength)]

[0047] Here, there is a correlation represented by the following formula between the content of block polymer A1 in copolymer (a') before hydrogenation measured by the osmium tetroxide decomposition method (referred to as the "Os value") and the content of block polymer A1 in hydrogenated copolymer (a) after hydrogenation measured by the NMR method (referred to as the "Ns value"). Os value = -0.012 (Ns value)² + 1.8 (Ns value) -13.0

[0048] <Vinyl bond content> The amount of vinyl bonds in the conjugated diene compound in the hydrogenated copolymer (a) before hydrogenation is preferably from 1 mol % to 39 mol %, more preferably from 5 mol % to 38 mol %, and even more preferably from 10 mol % to 37 mol %.

[0049] When the amount of vinyl bonds in the hydrogenated copolymer (a) before hydrogenation is 1 mol % or more, the tube using the hydrogenated copolymer of this embodiment will have excellent processability, transparency, and flexibility. When the amount of vinyl bonds in the hydrogenated copolymer (a) before hydrogenation is 39 mol % or less, the tube using the hydrogenated copolymer of this embodiment will tend to have excellent tensile properties.

[0050] In the present embodiment, the vinyl bond content refers to the total content of 1,2-vinyl bonds (conjugated dienes incorporated into the polymer via 1,2-bonds) and 3,4-vinyl bonds (conjugated dienes incorporated into the polymer via 3,4-bonds) relative to all conjugated dienes (here, when 1,3-butadiene is used as the conjugated diene, the 1,2-vinyl bond content is used, and when isoprene is used as the conjugated diene, the 3,4-vinyl bond content is used).

[0051] The vinyl bond content based on the conjugated diene before hydrogenation can be measured using a nuclear magnetic resonance (NMR) spectrometer. The microstructure (cis, trans, vinyl ratio) derived from the conjugated diene compound monomer units in the hydrogenated copolymer (a) can be optionally changed by using a polar compound, etc., as described below.

[0052] <Weight average molecular weight> The weight average molecular weight of the hydrogenated copolymer (a) is preferably from 100,000 to 800,000, more preferably from 120,000 to 500,000, and even more preferably from 140,000 to 400,000.

[0053] When the weight-average molecular weight of the hydrogenated copolymer (a) is 100,000 or more, the tube using the hydrogenated copolymer of this embodiment tends to have excellent tensile properties. When the weight-average molecular weight of the hydrogenated copolymer (a) is 800,000 or less, the flowability allowing molding and the molded appearance tend to be good.

[0054] The weight-average molecular weight of the hydrogenated copolymer (a) can be determined by measuring the molecular weight of the peak in a chromatogram by gel permeation chromatography (GPC) using the method described in the Examples below, and using a calibration curve (prepared using the peak molecular weights of the standard polystyrenes) obtained from measurements of commercially available standard polystyrenes.

[0055] The shape of the molecular weight distribution of the hydrogenated copolymer (a) measured by GPC is not particularly limited, and the hydrogenated copolymer (a) may have a polymodal molecular weight distribution with two or more peaks, or a monomodal molecular weight distribution with one peak.

[0056] The weight average molecular weight of the hydrogenated copolymer (a) can be controlled by adjusting the amount of monomer added during the polymerization step, the amount of reaction initiator added, the polymerization time, and the polymerization temperature.

[0057] The melt flow rate (MFR; according to ISO 1133) of the hydrogenated copolymer (a) is preferably in the range of 0.01 to 200 g / 10 min, more preferably 0.1 to 150 g / 10 min, and even more preferably 1.0 to 100 g / 10 min.

[0058] When the viscosity is 0.01 g / 10 min or more, the fluidity of the resulting tube tends to be sufficiently ensured, and when the viscosity is 200 g / 10 min or less, the low stickiness of the resulting tube tends to be sufficiently ensured.

[0059] (loss tangent (tanδ) peak temperature) In this embodiment, only one type of hydrogenated copolymer (a) may be used, or two or more types of hydrogenated copolymers (a) having different copolymer compositions may be mixed and used.

[0060] Hydrogenated copolymers (a) having different copolymerization compositions exhibit different loss tangent (tan δ) peak temperatures in the obtained dynamic viscoelasticity spectra.

[0061] In this embodiment, the hydrogenated copolymer (a) preferably has at least one tan δ peak temperature in the range of −40° C. to 50° C. A copolymer that uses butadiene as the conjugated diene and styrene as the aromatic vinyl and that has been hydrogenated to a hydrogenation rate of 80% by mass or more tends to exhibit a tan δ peak at this position.

[0062] By adjusting the content of the vinyl aromatic compound in the hydrogenated polymer block A2 in the hydrogenated copolymer (a) to 25 to 50 mass %, the tan δ peak temperature can be controlled within the range of -40°C to -10°C, and the copolymer has excellent low-temperature properties, handleability, and low stickiness.

[0063] On the other hand, by adjusting the content of the vinyl aromatic compound in the hydrogenated polymer block A2 in the hydrogenated copolymer (a) to 50 to 80 mass %, the tan δ peak temperature can be controlled within the range of -10°C to 50°C, and the tensile properties of the tube can be excellent.

[0064] The tan δ peak temperature can be easily controlled by incorporating a vinyl aromatic compound into the hydrogenated polymer block A2 of the hydrogenated copolymer (a). Specifically, it can be controlled by using a vinyl bond amount adjuster (a polar compound such as a tertiary amine compound or an ether compound) as described below, and by the hydrogenation rate. The tan δ peak temperature tends to increase as the content of the vinyl aromatic compound in the hydrogenated polymer block A2 of the hydrogenated copolymer (a) increases, and tends to decrease as the content decreases. Furthermore, the tan δ peak temperature tends to decrease as the hydrogenation rate increases.

[0065] (Method for producing hydrogenated copolymer (a)) Examples of methods for producing the hydrogenated copolymer (a) include, but are not limited to, methods described in Japanese Patent Publication Nos. 36-19286, 43-17979, 46-32415, 49-36957, 48-2423, 48-4106, 51-49567, and JP-A-59-166518.

[0066] The copolymer before hydrogenation can be obtained by, but not limited to, a method of carrying out living anionic polymerization using predetermined monomers in a hydrocarbon solvent using a polymerization initiator such as an organic alkali metal compound.

[0067] The hydrocarbon solvent is not particularly limited, and examples thereof include aliphatic hydrocarbons such as n-butane, isobutane, n-pentane, n-hexane, n-heptane, and n-octane; alicyclic hydrocarbons such as cyclohexane, cycloheptane, and methylcycloheptane; and aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene.

[0068] As the polymerization initiator, an organic alkali metal compound that is generally known to have anionic polymerization activity for conjugated diene compounds and vinyl aromatic compounds can be used.

[0069] For example, there may be mentioned aliphatic hydrocarbon alkali metal compounds having 1 to 20 carbon atoms, aromatic hydrocarbon alkali metal compounds having 1 to 20 carbon atoms, and organic amino alkali metal compounds having 1 to 20 carbon atoms.

[0070] The alkali metal contained in the polymerization initiator is not limited to the following, but examples thereof include lithium, sodium, and potassium. One or more types of alkali metals may be contained in one molecule.

[0071] Examples of the polymerization initiator include, but are not limited to, n-propyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, n-pentyllithium, n-hexyllithium, benzyllithium, phenyllithium, tolyllithium, a reaction product of diisopropenylbenzene and sec-butyllithium, and a reaction product of divinylbenzene, sec-butyllithium, and a small amount of 1,3-butadiene.

[0072] Furthermore, 1-(t-butoxy)propyllithium disclosed in U.S. Patent No. 5,708,092 and lithium compounds into which one to several molecules of isoprene monomer are inserted to improve solubility, siloxy group-containing alkyllithiums such as 1-(t-butyldimethylsiloxy)hexyllithium disclosed in British Patent No. 2,241,239, amino group-containing alkyllithiums disclosed in U.S. Patent No. 5,527,753, diisopropylamide lithium, hexamethyldisilazide lithium and other aminolithiums can also be used.

[0073] The amount of the lithium compound used as a polymerization initiator depends on the molecular weight of the target copolymer, but can generally be 0.01 to 0.5 phm (parts by mass per 100 parts by mass of monomer). The amount of the lithium compound used as a polymerization initiator is preferably 0.03 to 0.3 phm, more preferably 0.05 to 0.15 phm.

[0074] When a conjugated diene compound and a vinyl aromatic compound are copolymerized using an organic alkali metal compound as a polymerization initiator, a tertiary amine compound or an ether compound can be added as a vinyl bond amount adjuster to adjust the content of vinyl bonds (1,2-bonds or 3,4-bonds) resulting from the conjugated diene compound incorporated into the copolymer and to adjust the random copolymerization property of the conjugated diene compound and the vinyl aromatic compound.

[0075] The tertiary amine compound is not particularly limited, but examples thereof include compounds represented by the following formula: R1R2R3N (In the formula, R1, R2, and R3 are hydrocarbon groups having 1 to 20 carbon atoms or hydrocarbon groups having a tertiary amino group.)

[0076] Examples of such compounds include, but are not limited to, trimethylamine, triethylamine, tributylamine, N,N-dimethylaniline, N-ethylpiperidine, N-methylpyrrolidine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetraethylethylenediamine, 1,2-dipiperidinoethane, trimethylaminoethylpiperazine, N,N,N',N'',N''-pentamethylethylenetriamine, and N,N'-dioctyl-p-phenylenediamine. Of these, N,N,N',N'-tetramethylethylenediamine is preferred.

[0077] As the ether compound, a linear ether compound or a cyclic ether compound can be used.

[0078] Examples of the linear ether compound include dialkyl ether compounds of ethylene glycol such as dimethyl ether, diethyl ether, diphenyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and ethylene glycol dibutyl ether; and dialkyl ether compounds of diethylene glycol such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol dibutyl ether.

[0079] Examples of cyclic ether compounds include tetrahydrofuran, dioxane, 2,5-dimethyloxolane, 2,2,5,5-tetramethyloxolane, 2,2-bis(2-oxolanyl)propane, and alkyl ethers of furfuryl alcohol.

[0080] The amount of the tertiary amine compound or ether compound used is preferably 0.1 to 4 (mol / 1 mol of alkali metal), more preferably 0.2 to 3 (mol / 1 mol of alkali metal), relative to the amount of the organic alkali metal compound polymerization initiator.

[0081] In the process for producing the hydrogenated copolymer (a) and the hydrogenated copolymer (b) described below, sodium alkoxide may be present when copolymerization is carried out.

[0082] The sodium alkoxide is, for example, a compound represented by the following formula, but is not limited to the following: In particular, sodium alkoxides having an alkyl group with 3 to 6 carbon atoms are preferred, and sodium t-butoxide and sodium t-pentoxide are more preferred. NaOR (wherein R is an alkyl group having 2 to 12 carbon atoms)

[0083] The amount of sodium alkoxide used in the polymerization step of the hydrogenated copolymer (a) is preferably 0.01 or more and less than 0.1 (molar ratio), more preferably 0.01 or more and less than 0.08 (molar ratio), even more preferably 0.03 or more and less than 0.08 (molar ratio), and still more preferably 0.04 or more and less than 0.06 (molar ratio), relative to the vinyl bond amount adjuster (tertiary amine compound or ether compound).

[0084] When the amount of sodium alkoxide is within this range, it tends to be possible to produce at a high productivity a copolymer having a narrow molecular weight distribution and high strength, which has a copolymer block containing a conjugated diene compound with a high vinyl bond content and a polymer block mainly composed of a vinyl aromatic compound with a narrow molecular weight distribution.

[0085] The method for copolymerizing a conjugated diene compound and a vinyl aromatic compound using an organic alkali metal compound as a polymerization initiator is not particularly limited, and may be batch polymerization, continuous polymerization, or a combination thereof.

[0086] The polymerization temperature is not particularly limited, but is usually 0 to 180°C, and preferably 30 to 150°C.

[0087] The time required for polymerization varies depending on the conditions, but is usually within 48 hours, preferably 0.1 to 10 hours.

[0088] It is also preferable to carry out the polymerization in an atmosphere of an inert gas such as nitrogen gas.

[0089] The polymerization pressure is not particularly limited as long as it is within a pressure range sufficient to maintain the monomer and solvent in a liquid phase within the above-mentioned polymerization temperature range.

[0090] Furthermore, at the end of the polymerization, a required amount of a coupling agent having two or more functional groups may be added to carry out a coupling reaction.

[0091] The coupling agent having two or more functional groups is not particularly limited, and known agents can be used.

[0092] Examples of bifunctional coupling agents include, but are not limited to, dihalogen compounds such as dimethyldichlorosilane and dimethyldibromosilane, and acid esters such as methyl benzoate, ethyl benzoate, phenyl benzoate, and phthalates.

[0093] Examples of polyfunctional coupling agents having three or more functional groups include, but are not limited to, trivalent or higher polyalcohols, epoxidized soybean oil, polyvalent epoxy compounds such as diglycidyl bisphenol A, halogenated silicon compounds represented by the formula R1(4-n)SiXn (wherein R1 is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 3 or 4), and halogenated tin compounds.

[0094] Examples of halogenated silicon compounds include, but are not limited to, methylsilyl trichloride, t-butylsilyl trichloride, silicon tetrachloride, and brominated versions of these compounds.

[0095] Examples of the tin halide compound include, but are not limited to, polyvalent halogen compounds such as methyltin trichloride, t-butyltin trichloride, and tin tetrachloride. Dimethyl carbonate and diethyl carbonate can also be used.

[0096] The hydrogenated copolymer (a) may be obtained by subjecting the living terminal of the copolymer obtained by the above-mentioned method to an addition reaction with a modifier that generates a functional group-containing atomic group.

[0097] Examples of functional group-containing atomic groups include, but are not limited to, atomic groups containing at least one functional group selected from the group consisting of a hydroxyl group, a carbonyl group, a thiocarbonyl group, an acid halide group, an acid anhydride group, a carboxyl group, a thiocarboxylate group, an aldehyde group, a thioaldehyde group, a carboxylic acid ester group, an amide group, a sulfonic acid group, a sulfonate ester group, a phosphoric acid group, a phosphoric acid ester group, an amino group, an imino group, a nitrile group, a pyridyl group, a quinoline group, an epoxy group, a thioepoxy group, a sulfide group, an isocyanate group, an isothiocyanate group, a silicon halide group, a silanol group, an alkoxy silicon group, a tin halide group, an alkoxy tin group, and a phenyl tin group.

[0098] Examples of the modifying agent having a functional group-containing atomic group include, but are not limited to, tetraglycidyl meta-xylenediamine, tetraglycidyl-1,3-bisaminomethylcyclohexane, ε-caprolactone, δ-valerolactone, 4-methoxybenzophenone, γ-glycidoxyethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyldimethylphenoxysilane, bis(γ-glycidoxypropyl)methylpropoxysilane, 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, N,N'-dimethylpropyleneurea, and N-methylpyrrolidone.

[0099] The amount of the modifier added is preferably 0.01 to 40 parts by mass, more preferably 0.1 to 20 parts by mass, and even more preferably 0.3 to 10 parts by mass, relative to 100 parts by mass of the hydrogenated copolymer before modification.

[0100] The temperature for the addition reaction of the modifying agent is preferably 0 to 150°C, more preferably 20 to 120°C.

[0101] The time required for the modification reaction varies depending on the modification reaction conditions, but is preferably within 24 hours, more preferably 0.1 to 10 hours.

[0102] The hydrogenation catalyst used to produce the hydrogenated copolymers (a) and (b) is not particularly limited, and for example, the hydrogenation catalysts described in JP-B-42-8704, JP-B-43-6636, JP-B-63-4841, JP-B-1-37970, JP-B-1-53851, JP-B-2-9041, etc. can be used.

[0103] Preferred hydrogenation catalysts include titanocene compounds and / or mixtures with reducing organometallic compounds.

[0104] The titanocene compound is not particularly limited, but examples thereof include compounds described in JP-A-8-109219, and specific examples thereof include compounds having at least one or more ligands having a (substituted) cyclopentadienyl structure, an indenyl structure, and a fluorenyl structure, such as biscyclopentadienyltitanium dichloride and monopentamethylcyclopentadienyltitanium trichloride.

[0105] The reducing organometallic compound is not particularly limited, but examples thereof include organic alkali metal compounds such as organolithium compounds, organomagnesium compounds, organoaluminum compounds, organoboron compounds, and organozinc compounds.

[0106] The reaction temperature for the hydrogenation reaction is usually 0 to 200°C, preferably 30 to 150°C.

[0107] The pressure of hydrogen used in the hydrogenation reaction is preferably 0.1 to 30 MPa, more preferably 0.2 to 10 MPa, and even more preferably 0.3 to 5 MPa.

[0108] The reaction time for the hydrogenation reaction is usually 3 minutes to 10 hours, preferably 10 minutes to 5 hours.

[0109] The hydrogenation reaction can be carried out by a batch process, a continuous process, or a combination thereof.

[0110] After the hydrogenation reaction is completed, the catalyst residue may be removed from the reaction solution, if necessary.

[0111] Methods for separating the hydrogenated copolymer from the solvent include, but are not limited to, a method in which a polar solvent that is a poor solvent for the hydrogenated copolymer, such as acetone or alcohol, is added to a solution of the hydrogenated copolymer to precipitate and recover the hydrogenated copolymer; a method in which the solution of the hydrogenated copolymer is poured into hot water with stirring and the solvent is removed by steam stripping to recover the hydrogenated copolymer; and a method in which the solvent is distilled off by directly heating the solution of the hydrogenated copolymer.

[0112] The hydrogenated copolymer of this embodiment may contain an antioxidant on the surface and / or inside thereof, for example, by adding an antioxidant during production. The following antioxidant may also be added to the resin composition of the present embodiment, which will be described later.

[0113] Examples of antioxidants include, but are not limited to, phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, and amine-based antioxidants.

[0114] Specifically, 2,6-di-t-butyl-4-methylphenol, n-octadecyl-3-(4'-hydroxy-3',5'-di-t-butyl-phenyl)propionate, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane], tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, 4,4'-butylidene-bis-(3-methyl-6-t-butylphenol), 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methyl phenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)1,3,5-triazine, pentaerythrityl-tetrakis[3 -(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, bis(3,5-di-t-butyl-4 -hydroxybenzylphosphonic acid ethyl) calcium and polyethylene wax (50%) mixture, octylated diphenylamine, 2,4-bis[(octylthio)methyl]-o-cresol, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, butylic acid, 3,3-bis(3-t-butyl-4-hydroxyphenyl)ethylene ester, 1,1,3-tris-(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 2-t-butyl-6-(3'-t-butyl-5'-methyl-2'-hydroxybenzyl)-4-methylphenyl-acrylate, and 2-[1-(2-hydroxy-3,5-di-t-pentylphenyl)-ethyl]-4,6-di-t-pentylphenyl acrylate.

[0115] The hydrogenated copolymer (a) may be pelletized.

[0116] Examples of pelletizing methods include a method in which the hydrogenated copolymer (a) is extruded in the form of a strand from a single-screw or twin-screw extruder and cut in water with a rotary blade installed in front of the die; a method in which the hydrogenated copolymer is extruded in the form of a strand from a single-screw or twin-screw extruder, cooled with water or air, and then cut with a strand cutter; a method in which the copolymer is melt-mixed using an open roll or Banbury mixer, formed into a sheet using a roll, and the sheet is cut into strips and then cut into cubic pellets using a pelletizer. The size and shape of the pellets of the hydrogenated copolymer (a) are not particularly limited.

[0117] If necessary, the hydrogenated copolymer (a) may be blended with a pellet anti-blocking agent in order to prevent blocking between the pellets.

[0118] Examples of pellet blocking inhibitors include, but are not limited to, calcium stearate, magnesium stearate, zinc stearate, polyethylene, polypropylene, ethylene bisstearylamide, talc, and amorphous silica.

[0119] The amount of the pellet anti-blocking agent to be added is preferably 500 to 10,000 ppm, more preferably 1,000 to 5,000 ppm, relative to the hydrogenated copolymer (a). The pellet anti-blocking agent is preferably added in a state where it is attached to the pellet surface, but may also be contained to some extent inside the pellet.

[0120] [Other ingredients] The tube of this embodiment may contain other components in addition to the hydrogenated copolymer (a) described above, provided that the object of this embodiment is not impaired. The other components are not particularly limited, and examples include hydrogenated copolymer (b) having a structure different from that of hydrogenated copolymer (a), heat stabilizers, antioxidants, UV absorbers, antioxidants, plasticizers, light stabilizers, nucleating agents, impact modifiers, pigments, lubricants, antistatic agents, dispersants, flame retardants, copper inhibitors, crosslinking agents, flame retardant aids, compatibilizers, and tackifiers. These other components may be used alone or in combination of two or more.

[0121] [Hydrogenated copolymer (b)] The tube of the present embodiment may further contain 0.1 to 20 mass % of a hydrogenated copolymer (b) other than the hydrogenated copolymer (a).

[0122] The hydrogenated copolymer (b) preferably comprises a polymer block B1 mainly composed of a vinyl aromatic compound and a polymer block B2 mainly composed of a conjugated diene compound, and the content of the polymer block B1 mainly composed of a vinyl aromatic compound in the hydrogenated copolymer (b) is 45 to 80 mass % and the content of the polymer block B2 mainly composed of a conjugated diene compound is 20 to 55 mass %, and the hydrogenation rate of the hydrogenated block copolymer (b) is preferably 80 mol % or more.

[0123] In the hydrogenated copolymer (b), the definition of "mainly composed of," the materials of the conjugated diene compound and the vinyl aromatic compound, the vinyl bond amount, and the hydrogenation rate can be defined, controlled, and quantified in the same manner as in the hydrogenated copolymer (a) described above. The hydrogenated copolymer (b) can be produced by the same method as the hydrogenated copolymer (a) described above.

[0124] [Lubricant] The tube of this embodiment may contain a lubricant (c) to prevent adhesion between the surfaces or the insides of the tube and to improve the texture, such as the feel to the touch. As the lubricant (c), it is preferable to contain at least one lubricant (preferably at least two) selected from fatty acid amide-based lubricants, metal stearate-based lubricants, and fatty acid monoglyceride-based lubricants.

[0125] Examples of fatty acid amide lubricants include, but are not limited to, erucamide, behenamide, oleamide, stearamide, N-stearyl laurate, N-stearyl stearamide, N-stearyl behenamide, N-stearyl erucamide, N-oleyl oleate, N-oleyl behenamide, N-lauryl erucamide, ethylene bisoleate, ethylene bisstearamide, hexamethylene bisoleate, hexamethylene biserucamide, etc. Among these, erucamide, behenamide, oleate, stearamide, and ethylene bisstearamide are preferred, and oleate is more preferred.

[0126] Metal species of the metal stearate-based lubricant include zinc, sodium, calcium, magnesium, lithium, etc. Among these, zinc stearate is preferred.

[0127] Examples of fatty acid monoglyceride lubricants include, but are not limited to, lauric acid monoglyceride, myristic acid monoglyceride, palmitic acid monoglyceride, stearic acid monoglyceride, oleic acid monoglyceride, behenic acid monoglyceride, etc. Among these, stearic acid monoglyceride is preferred.

[0128] The content of lubricant in the resin composition constituting the tube of this embodiment is preferably 0.05% by mass or more from the viewpoint of preventing adhesion, and is preferably 1.0% by mass or less, more preferably 0.7% by mass or less, from the viewpoint of preventing the lubricant from bleeding out from the inside of the tube and interfering with printability on the tube surface. From these viewpoints, the content of lubricant in the hydrogenated copolymer constituting the tube of this embodiment is preferably in the range of 0.05 to 1.0% by mass, more preferably 0.05 to 0.7% by mass.

[0129] The fatty acid amide lubricants, metal stearate lubricants, and fatty acid monoglyceride lubricants may each be used alone or in combination of two or more. Among these, it is preferred to use erucic acid amide, zinc stearate, and ethylene bisstearic acid amide in combination, with the ratio of erucic acid amide / zinc stearate / ethylene bisstearic acid amide being preferably 0.20 / 0.15 / 0.15.

[0130] [Softener] The tube of this embodiment may contain a softener. Examples of softeners include paraffinic oil, naphthenic oil, aromatic oil, paraffin wax, liquid paraffin, white mineral oil, and vegetable softeners. Among these, paraffinic oil, liquid paraffin, and white mineral oil are more preferred from the viewpoints of the low-temperature properties and bleeding resistance of the thermoplastic elastomer composition of this embodiment and the molded article.

[0131] The kinematic viscosity of the softener at 40°C is preferably 500 mm / sec or less. The lower limit of the kinematic viscosity of the softener at 40°C is not particularly limited, but it is preferably 10 mm / sec. If the kinematic viscosity of the softener at 40°C is 500 mm / sec or less, the fluidity of the tube of this embodiment tends to be further improved, and the moldability tends to be further improved. The kinematic viscosity of the softener can be measured by a method such as testing using a glass capillary viscometer.

[0132] [Tackifier] The tube of this embodiment may contain a tackifier, such as coumarone-indene resin, pt-butylphenol-acetylene resin, phenol-formaldehyde resin, xylene-formaldehyde resin, terpene resin, hydrogenated terpene resin, terpene-phenol resin, aromatic hydrocarbon resin, aliphatic hydrocarbon resin, aliphatic cyclic hydrocarbon resin, aliphatic-alicyclic petroleum resin, aliphatic-aromatic hydrocarbon resin, hydrogenated modified alicyclic hydrocarbon resin, hydrogenated alicyclic hydrocarbon resin, hydrocarbon tackifying resin, polybutene, liquid polybutadiene, cis-1,4-polyisoprene rubber, hydrogenated polyisoprene rubber, liquid polyisoprene rubber, and rosin-based resin.

[0133] [Polyolefin resin] In this embodiment, it is preferable that the hydrogenated copolymer (a) does not contain a polyolefin resin. If a polyolefin resin is contained, the solvent adhesion and transparency of the tube tend to deteriorate and the tube tends to whiten. Examples of polyolefin resins include polypropylene and polyethylene.

[0134] [Tube manufacturing method] (Manufacturing method of material that constitutes the tube) The material constituting the tube of this embodiment can be prepared, for example, by appropriately selecting the hydrogenated copolymer (a) and other components to be added as needed, and dry-blending them, or by adjusting the material using an apparatus typically used for mixing polymeric substances.

[0135] The mixing device is not particularly limited, but examples thereof include kneading devices such as a Banbury mixer, a Labo Plastomill, a single-screw extruder, and a twin-screw extruder. From the viewpoints of productivity and good kneading, production by a melt mixing method using an extruder is preferred. The melt temperature during kneading can be appropriately set, but is usually in the range of 130 to 300°C, and preferably in the range of 150 to 250°C.

[0136] (Tube forming method) The method for forming the tube of this embodiment is not particularly limited, but for example, the hydrogenated copolymer (a) and other components added as necessary may be appropriately selected, charged into an extruder, melted, passed through a die to form a tubular shape, and cooled with water or air to form a tube. A single-screw or multi-screw extruder may be used as the extruder, and a multi-layer extruded tube may also be formed using multiple extruders.

[0137] The shape of the tube is not particularly limited, but circular, oval, or other shapes are usually used. The thickness of the tube is not particularly limited, but for example, the outer diameter is preferably 1 to 50 mm, more preferably 2 to 30 mm, and even more preferably 3 to 20 mm. The thickness of the tube is preferably 0.3 to 30 mm, more preferably 0.4 to 20 mm, and even more preferably 0.5 to 10 mm.

[0138] The tube of this embodiment may be formed into a multilayer tube by laminating other polymers to the extent that the object of this embodiment is not impaired. The above polymers may be used singly or in combination of two or more, with different types in a single layer or in each layer, or laminated in multiple layers. Furthermore, by appropriately selecting two or more different polymers through multilayering, it is possible to obtain a tube with different hardness in different regions and yet without seams. The layer made of the above polymer in the above multilayer tube may be the innermost layer, intermediate layer, or outermost layer, depending on the desired performance to be imparted.

[0139] In this embodiment, in order to further improve pressure resistance while suppressing an increase in wall thickness and maintaining flexibility, a pressure-resistant tube (hose) can be made by winding a braided reinforcing thread or a spiral reinforcing body. The braided reinforcing thread is provided inside or between layers in the thickness direction, and vinylon, polyamide, polyester, aramid fiber, carbon fiber, metal wire, etc. can be used, while the spiral reinforcing body is provided on the outer periphery, and metal, plastic, etc. can be used.

[0140] As will be shown in the examples below, the tube of this embodiment has excellent transparency, flexibility, kink resistance, solvent adhesion, and a good balance of each property at a high level, and can be used for any purpose without any particular restrictions.

[0141] By taking advantage of the above properties, the tube of the present embodiment can be used in a wide range of applications, such as home appliance applications, automobile interior and exterior parts applications, daily necessities, leisure goods, toys, industrial products, food manufacturing equipment applications, medical applications, etc. Among these, the tube of the present embodiment can be particularly suitably used for medical applications.

[0142] For example, single-layer or triple-layer tubes with an outer diameter of 7 mm and an inner diameter of 5 mm are often used for peritoneal dialysis bags, and single-layer tubes with an outer diameter of 4 mm and an inner diameter of 3 mm are often used for infusion bags. However, the tube of this embodiment is suitable for these shapes because it has excellent transparency, flexibility, kink resistance, solvent adhesion, and a high level of balance of each property.

[0143] In an embodiment, a medical tubing made from the hydrogenated copolymer requires a peel force of at least 30 N to separate a solvent-soaked medical tubing from a plastic connector, regardless of the type of connector or solvent. Examples of connectors include polyolefin, polyester, polycarbonate, polyvinyl chloride, polyether ketone, ABS, polystyrene, polyamide, polyimide, polyoxymethylene, polyacrylate, polyurethane, or polysulfone, and examples of connectors include solvents such as tetrahydrofuran, cyclohexanone, cyclohexane, methyl ethyl ketone, and the like. Furthermore, when producing medical tubing and connectors on a production line, a high peel force is required even for short solvent immersion. In an embodiment, a medical tubing made from the hydrogenated copolymer needs to dissolve quickly when soaked in a solvent, regardless of the type of solvent.

[0144] The medical tube can be suitably used as a tube for an infusion set, a tube for an enteral nutrition set, an extension tube, a drug administration tube, a tube for a blood circuit, a feeding tube, a connecting tube, a tube for a winged intravenous needle, and also as a suction catheter, a drainage catheter, an enteral nutrition catheter, a gastric tube catheter, a drug administration catheter, a blood catheter and a balloon catheter, a urethral catheter, etc. [Example]

[0145] The present invention will be described in detail below with reference to specific examples and comparative examples, but the present invention is not limited to the following examples.

[0146] First, the evaluation methods and methods for measuring physical properties applied to the examples and comparative examples are described below.

[0147] [Method for identifying the structure of hydrogenated copolymer (a) and hydrogenated copolymer (b) and method for measuring physical properties] (Total vinyl aromatic compound content in hydrogenated copolymer) The total vinyl aromatic compound content (mass%) of each copolymer was calculated from the absorption intensity at 262 nm using an ultraviolet spectrophotometer (Shimadzu Corporation, UV-2450) before hydrogenation.

[0148] Since the content of all vinyl aromatic compound monomer units does not change significantly before and after hydrogenation, the content of all vinyl aromatic compound monomer units (styrene monomer units) obtained for the copolymer before hydrogenation was used as the content of all vinyl aromatic compound monomer units (total styrene content) of the hydrogenated copolymer.

[0149] (Content (Os value) of polymer block A1 or polymer block B1 in hydrogenated copolymer) Using the copolymer before hydrogenation, the measurement was carried out by the osmium tetroxide decomposition method described in I. M. Kolthoff et al., J. Polym. Soi. 1, 429 (1946).

[0150] The copolymer before hydrogenation was decomposed using a 0.1 g / 125 mL tertiary butanol solution of osmic acid. The polystyrene block content obtained here is referred to as the "Os value."

[0151] (Amount of vinyl aromatic compound in polymer block A2 or B2) Using the hydrogenated block copolymer as a measurement sample, polymer blocks mainly composed of vinyl aromatic compounds and polymer blocks composed of vinyl aromatic compounds and conjugated diene compounds were distinguished by proton nuclear magnetic resonance spectroscopy (H-NMR, ECS400 manufactured by JOEL RESONABCE).

[0152] Deuterated chloroform was used as the solvent, the sample concentration was 50 mg / mL, the observation frequency was 400 MHz, tetramethylsilane was used as the chemical shift standard, the pulse delay was 2.904 seconds, the number of scans was 256, and the measurement temperature was 23°C. From the integrated intensity of the signals assigned to aromatics, the random and block aromatics were calculated from the integrated value per 1H of each bonding mode, and then the total styrene content was calculated using the method described above, and the content ratio was calculated.

[0153] (Amount of vinyl bond in polymer block A2) Polymer samples taken at each step of the polymerization process of the copolymer before hydrogenation were analyzed for vinyl bond content (1,2-bond content) by proton nuclear magnetic resonance (H-NMR) analysis using a nuclear magnetic resonance spectrometer (BRUKER, DPX-400). Deuterated chloroform was used as the solvent, the sample concentration was 50 mg / mL, the observation frequency was 400 MHz, tetramethylsilane was used as the chemical shift standard, the pulse delay was 2.904 seconds, the number of scans was 64, the pulse width was 45°C, and the measurement temperature was 26°C. The vinyl bond content was calculated by calculating the integral per 1H of each bond type from the integrals of the signals assigned to 1,4- and 1,2-bonds, and then calculating the ratio of 1,2-bonds to the sum of 1,4- and 1,2-bonds.

[0154] (Weight average molecular weight of hydrogenated copolymer) Measurement was performed using GPC (apparatus: Tosoh HLC8220, column: TSKgel SuperH-RC x 2). Tetrahydrofuran was used as the solvent. Measurement was performed at a temperature of 35°C. A calibration curve was prepared using commercially available standard polystyrenes with known weight-average molecular weights, and the weight-average molecular weight converted into polystyrene was determined.

[0155] (Hydrogenation rate of hydrogenated copolymer (hydrogenation rate)) The hydrogenation rate of the hydrogenated copolymer was measured using a nuclear magnetic resonance spectrometer (BRUKER, DPX-400). The hydrogenated copolymer, which is the copolymer after hydrogenation, was measured by proton nuclear magnetic resonance (H-NMR). Specifically, the integral values ​​of the signals derived from the residual double bonds in the range of 4.5 to 5.5 ppm and the signals derived from the hydrogenated conjugated diene were calculated, and the ratio thereof was calculated.

[0156] (Hardness of hydrogenated copolymer) The hydrogenated copolymer was press-molded at 200°C to form four sheets each 2 mm thick, and the instantaneous and 10-second values ​​were measured using a durometer type A in accordance with ASTM D-2240.

[0157] (MFR of hydrogenated copolymer) The MFR of the hydrogenated copolymer was measured at 230°C under a load of 2.16 kg in accordance with ISO1133.

[0158] (Refractive index of hydrogenated copolymer) The refractive index (D line, 589 nm, 23°C) of the hydrogenated copolymer (a) was measured using an Abbe refractometer (device name DR-M2, manufactured by Atago Co., Ltd.) in accordance with JIS K7142. A 2 mm thick sheet of each polymer was used as the sample.

[0159] [Production of hydrogenated copolymer] (Preparation of hydrogenation catalyst) The hydrogenation catalyst used in the hydrogenation reaction of the copolymer was prepared by the following method. A nitrogen-purged reaction vessel was charged with 1 liter of dried and purified cyclohexane, and 100 mmol of biscyclopentadienyltitanium dichloride was added. With sufficient stirring, an n-hexane solution containing 200 mmol of trimethylaluminum was added, and the mixture was reacted at room temperature for approximately 3 days to obtain a hydrogenation catalyst.

[0160] (Hydrogenated copolymer) The hydrogenated copolymers (a-1) to (a-9) were prepared as follows.

[0161] <Hydrogenated copolymer (a-1)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 20 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.084 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.35 mol of N,N,N',N'-tetramethylethylenediamine relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70°C for 20 minutes. Next, a cyclohexane solution containing 47 parts by mass of styrene and a cyclohexane solution containing 33 parts by mass of butadiene (concentration: 20% by mass) were added, and polymerization was carried out at 70° C. for 1 hour. Next, 0.25 mol of ethyl benzoate was added per 1 mol of n-butyllithium, and the mixture was reacted at 70° C. for 10 minutes. Thereafter, methanol was added to terminate the polymerization reaction.

[0162] The copolymer obtained as described above had a styrene content of 67% by mass, a polymer block A1 content of 20% by mass, a vinyl bond amount in polymer block A2 before hydrogenation of 25%, and a weight average molecular weight of 193,000. The coupling rate determined from the peak area ratio of the GPC curve was 50%. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained copolymer in an amount of 50 ppm (Ti basis) per 100 parts by mass of the copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C. The hydrogenation rate of the resulting hydrogenated copolymer was 98%.

[0163] Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the hydrogenated copolymer to obtain a hydrogenated copolymer (a-1).

[0164] <Hydrogenated copolymer (a-2)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 7.5 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.080 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.35 mol of N,N,N',N'-tetramethylethylenediamine relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70°C for 20 minutes. Next, a cyclohexane solution containing 36 parts by mass of styrene and a cyclohexane solution containing 49 parts by mass of butadiene (concentration: 20% by mass) were added, and polymerization was carried out at 70° C. for 1 hour. Next, a cyclohexane solution containing 7.5 parts by mass of styrene was added, and polymerization was carried out at 60° C. for 20 minutes. Thereafter, methanol was added to terminate the polymerization reaction.

[0165] The copolymer obtained as described above had a styrene content of 51% by mass, a polymer block A1 content of 15% by mass, a vinyl bond amount in polymer block A2 before hydrogenation of 22%, and a weight average molecular weight of 151,000. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained copolymer in an amount of 50 ppm (Ti basis) per 100 parts by mass of the copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C. The hydrogenation rate of the resulting hydrogenated copolymer was 98%.

[0166] Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the hydrogenated copolymer to obtain a hydrogenated copolymer (a-2).

[0167] <Hydrogenated copolymer (a-3)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 20 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.084 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.35 mol of N,N,N',N'-tetramethylethylenediamine relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70°C for 20 minutes. Next, a cyclohexane solution containing 60 parts by mass of styrene and a cyclohexane solution containing 20 parts by mass of butadiene (concentration: 20% by mass) were added, and polymerization was carried out at 70° C. for 1 hour. Next, 0.25 mol of ethyl benzoate was added per 1 mol of n-butyllithium, and the mixture was reacted at 70° C. for 10 minutes. Thereafter, methanol was added to terminate the polymerization reaction.

[0168] The copolymer obtained as described above had a styrene content of 80% by mass, a polymer block A1 content of 20% by mass, a vinyl bond amount in polymer block A2 before hydrogenation of 25%, and a weight average molecular weight of 193,000. The coupling rate determined from the peak area ratio of the GPC curve was 50%. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained copolymer in an amount of 50 ppm (Ti basis) per 100 parts by mass of the copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C. The hydrogenation rate of the resulting hydrogenated copolymer was 98%.

[0169] Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the hydrogenated copolymer to obtain a hydrogenated copolymer (a-3).

[0170] <Hydrogenated copolymer (a-4)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 20 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.084 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.35 mol of N,N,N',N'-tetramethylethylenediamine relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70°C for 20 minutes. Next, a cyclohexane solution containing 28 parts by mass of styrene and a cyclohexane solution containing 52 parts by mass of butadiene (concentration: 20% by mass) were added, and polymerization was carried out at 70° C. for 1 hour. Next, 0.25 mol of ethyl benzoate was added per 1 mol of n-butyllithium, and the mixture was reacted at 70° C. for 10 minutes. Thereafter, methanol was added to terminate the polymerization reaction.

[0171] The copolymer obtained as described above had a styrene content of 48% by mass, a polymer block A1 content of 20% by mass, a vinyl bond amount in polymer block A2 before hydrogenation of 25%, and a weight average molecular weight of 193,000. The coupling rate determined from the peak area ratio of the GPC curve was 50%. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained copolymer in an amount of 50 ppm (Ti basis) per 100 parts by mass of the copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C. The hydrogenation rate of the resulting hydrogenated copolymer was 98%.

[0172] Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the hydrogenated copolymer to obtain a hydrogenated copolymer (a-4).

[0173] <Hydrogenated copolymer (a-5)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 2 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.084 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.35 mol of N,N,N',N'-tetramethylethylenediamine relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70°C for 20 minutes. Next, a cyclohexane solution containing 58 parts by mass of styrene and a cyclohexane solution containing 40 parts by mass of butadiene (concentration: 20% by mass) were added, and polymerization was carried out at 70° C. for 1 hour. Next, 0.25 mol of ethyl benzoate was added per 1 mol of n-butyllithium, and the mixture was reacted at 70° C. for 10 minutes. Thereafter, methanol was added to terminate the polymerization reaction.

[0174] The copolymer obtained as described above had a styrene content of 60% by mass, a polymer block A1 content of 2% by mass, a vinyl bond amount in polymer block A2 before hydrogenation of 25%, and a weight average molecular weight of 193,000. The coupling rate determined from the peak area ratio of the GPC curve was 50%. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained copolymer in an amount of 50 ppm (Ti basis) per 100 parts by mass of the copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C. The hydrogenation rate of the resulting hydrogenated copolymer was 98%.

[0175] Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the hydrogenated copolymer to obtain a hydrogenated copolymer (a-5).

[0176] <Hydrogenated copolymer (a-6)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 38 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.084 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.35 mol of N,N,N',N'-tetramethylethylenediamine relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70°C for 20 minutes. Next, a cyclohexane solution containing 36 parts by mass of styrene and a cyclohexane solution containing 26 parts by mass of butadiene (concentration: 20% by mass) were added, and polymerization was carried out at 70° C. for 1 hour. Next, 0.25 mol of ethyl benzoate was added per 1 mol of n-butyllithium, and the mixture was reacted at 70° C. for 10 minutes. Thereafter, methanol was added to terminate the polymerization reaction.

[0177] The copolymer obtained as described above had a styrene content of 74% by mass, a polymer block A1 content of 38% by mass, a vinyl bond amount in polymer block A2 before hydrogenation of 25%, and a weight average molecular weight of 193,000. The coupling rate determined from the peak area ratio of the GPC curve was 50%. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained copolymer in an amount of 50 ppm (Ti basis) per 100 parts by mass of the copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C. The hydrogenation rate of the resulting hydrogenated copolymer was 98%.

[0178] Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the hydrogenated copolymer to obtain a hydrogenated copolymer (a-6).

[0179] <Hydrogenated copolymer (a-7)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 20 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.084 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.02 mol of N,N,N',N'-tetramethylethylenediamine relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70°C for 20 minutes. Next, a cyclohexane solution containing 47 parts by mass of styrene and a cyclohexane solution containing 33 parts by mass of butadiene (concentration: 20% by mass) were added, and polymerization was carried out at 70° C. for 1 hour. Next, 0.25 mol of ethyl benzoate was added per 1 mol of n-butyllithium, and the mixture was reacted at 70° C. for 10 minutes. Thereafter, methanol was added to terminate the polymerization reaction.

[0180] The copolymer obtained as described above had a styrene content of 67% by mass, a polymer block A1 content of 20% by mass, a vinyl bond amount in polymer block A2 before hydrogenation of 3%, and a weight average molecular weight of 193,000. The coupling rate determined from the peak area ratio of the GPC curve was 50%. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained copolymer in an amount of 50 ppm (Ti basis) per 100 parts by mass of the copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C. The hydrogenation rate of the resulting hydrogenated copolymer was 98%.

[0181] Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the hydrogenated copolymer to obtain a hydrogenated copolymer (a-7).

[0182] <Hydrogenated copolymer (a-8)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 20 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.084 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.50 mol of N,N,N',N'-tetramethylethylenediamine relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70°C for 20 minutes. Next, a cyclohexane solution containing 47 parts by mass of styrene and a cyclohexane solution containing 33 parts by mass of butadiene (concentration: 20% by mass) were added, and polymerization was carried out at 70° C. for 1 hour. Next, 0.25 mol of ethyl benzoate was added per 1 mol of n-butyllithium, and the mixture was reacted at 70° C. for 10 minutes. Thereafter, methanol was added to terminate the polymerization reaction.

[0183] The copolymer obtained as described above had a styrene content of 67% by mass, a polymer block A1 content of 20% by mass, a vinyl bond amount in polymer block A2 before hydrogenation of 35%, and a weight average molecular weight of 193,000. The coupling rate determined from the peak area ratio of the GPC curve was 50%. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained copolymer in an amount of 50 ppm (Ti basis) per 100 parts by mass of the copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C. The hydrogenation rate of the resulting hydrogenated copolymer was 98%.

[0184] Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the hydrogenated copolymer to obtain a hydrogenated copolymer (a-8).

[0185] <Hydrogenated copolymer (a-9)> Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 20 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.084 parts by mass of n-butyllithium relative to 100 parts by mass of the total monomers and 0.35 mol of N,N,N',N'-tetramethylethylenediamine relative to 1 mol of n-butyllithium were added, and polymerization was carried out at 70°C for 20 minutes. Next, a cyclohexane solution containing 47 parts by mass of styrene and a cyclohexane solution containing 33 parts by mass of butadiene (concentration: 20% by mass) were added, and polymerization was carried out at 70° C. for 1 hour. Next, 0.25 mol of ethyl benzoate was added per 1 mol of n-butyllithium, and the mixture was reacted at 70° C. for 10 minutes. Thereafter, methanol was added to terminate the polymerization reaction.

[0186] The copolymer obtained as described above had a styrene content of 67% by mass, a polymer block A1 content of 20% by mass, a vinyl bond amount in polymer block A2 before hydrogenation of 25%, and a weight average molecular weight of 193,000. The coupling rate determined from the peak area ratio of the GPC curve was 50%. Furthermore, the hydrogenation catalyst prepared as described above was added to the obtained copolymer in an amount of 50 ppm (Ti basis) per 100 parts by mass of the copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C, and the reaction was stopped midway. The hydrogenation rate of the resulting hydrogenated copolymer was 80%.

[0187] Next, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the hydrogenated copolymer to obtain a hydrogenated copolymer (a-9).

[0188] The structural composition of each hydrogenated copolymer is shown in Table 1.

[0189] [Table 1]

[0190] [Tube manufacturing] (Examples 1 to 9, 11 to 21) Based on the blending ratios (parts by mass) of the examples shown in Tables 2 and 3, pellets of the hydrogenated copolymer (a) shown in Table 1 were extruded in a single-screw extruder equipped with a tube die at an extrusion temperature of 210°C and a take-up speed of 20 m / min, and then water-cooled in a cooling tank to obtain a single-layer tube having an outer diameter of 4.0 mm, an inner diameter of 2.7 mm, and a wall thickness of 0.65 mm. In the examples shown in Table 3, the hydrogenated copolymer (a) and the styrene-based thermoplastic elastomer A were blended. Styrene-based thermoplastic elastomer A: Asahi Kasei Corporation's "Tuftec (registered trademark) H1043" (hydrogenated styrene-butadiene-styrene block copolymer) [MFR (ISO 1133 (230°C, load 2.16 kg)): 1.5 g / 10 min, styrene unit content: 67% by mass, A hardness (instantaneous value): 97, A hardness (after 10 seconds): 96, refractive index: 1.552]

[0191] (Example 10 in Table 2) Polypropylene: SunAllomer "PC630A" (propylene-ethylene random copolymer) [MFR (JIS K7210 (230°C, load 2.16 kg): 7.5 g / 10 min] The mixture was dry-blended at a ratio of hydrogenated copolymer (a-1) / polypropylene=90 / 10, and molded using a single-screw extruder equipped with a tube die at an extrusion temperature of 210°C and a take-up speed of 20 m / min. The mixture was then water-cooled in a cooling bath to obtain a single-layer tube having an outer diameter of 4.0 mm, an inner diameter of 2.7 mm, and a wall thickness of 0.65 mm.

[0192] (Comparative Example 1 in Table 2) Styrene-based thermoplastic elastomer B: "Tuftec (registered trademark) H1221" (hydrogenated styrene-butadiene-styrene block copolymer) manufactured by Asahi Kasei Corporation [MFR (ISO 1133 (230°C, load 2.16 kg)): 4.5 g / 10 min, styrene unit content: 12% by mass] Polypropylene: SunAllomer "PC630A" (propylene-ethylene random copolymer) [MFR (JIS K7210 (230°C, load 2.16 kg): 7.5 g / 10 min] The mixture was dry-blended in a ratio of 70 / 30 styrene thermoplastic elastomer / polypropylene, and molded using a single-screw extruder equipped with a tube die at an extrusion temperature of 210°C and a take-up speed of 20 m / min. The mixture was then water-cooled in a cooling bath to obtain a single-layer tube with an outer diameter of 4.0 mm, an inner diameter of 2.7 mm, and a wall thickness of 0.65 mm.

[0193] (Comparative Example 2 in Table 2) The PVC tube used was the Terumo "Terufusion Infusion Set (automatic drop-type infusion set with pump connection)."

[0194] [Table 2]

[0195] [Table 3]

[0196] (Tube property evaluation) (kink resistance) The tube was cut to a length of 200 mm, and both ends of the tube were aligned and clamped with a clip or similar. A finger was slowly pressed down and traced from both ends of the clamped tube toward the center of the tube so that the two ends were in contact and parallel, and the finger was stopped at the point where the center of the tube buckled, and the distance from the center of the tube was measured. The shorter this distance, the better the kink resistance.

[0197] (solvent soluble) The tubes were immersed in tetrahydrofuran (THF), methyl ethyl ketone (MEK), cyclohexanone, and cyclohexane (c-Hex) at 23°C for 5 minutes, 30 minutes, and 120 minutes, and the appearance after immersion (tube shape, confirmation of whether or not it dissolved) was visually observed to evaluate the solvent solubility.

[0198] (solvent adhesion) The tube was heat-pressed at 200°C and cut into a sheet (10 mm x 10 mm x 0.5 mm) to prepare test specimens. The test specimens were dipped in tetrahydrofuran (THF), methyl ethyl ketone (MEK), cyclohexanone, or cyclohexane (c-Hex) for 1 second, sandwiched between two adherends (ABS and PC plates, 10 mm x 70 mm x 1 mm), and then dried for 24 hours at 23°C. While gripping the adherends, measurements were taken using a tensile tester at a peel rate of 300 mm / min. The maximum strength was used as an index of solvent adhesion.

[0199] (Radiation sterilization) The hydrogenated copolymer (a) and other materials used for the tube were heat-pressed at 200°C to form sheets (2 mm thick) which were then irradiated with gamma rays (25 kGy) and electron beams (40 kGy). Tensile tests (JIS No. 5, 500 mm / min) were conducted on the sheets before and after irradiation, and the presence or absence of changes in physical properties was used as an index of radiation sterilization resistance. The evaluation criteria were as follows: (Young's modulus) ○: The Young's modulus of the sheet before irradiation is maintained at 90% or more. ×: The Young's modulus of the sheet before irradiation was not maintained at 90% or more. (strength) ○: The sheet maintains 90% or more of its strength before irradiation ×: The sheet strength before irradiation was not maintained at 90% or more. (Elongation at break) ○: The sheet maintains 90% or more of its breaking elongation before irradiation ×: The sheet breaking elongation before irradiation was not maintained at 90% or more.

[0200] (Tactile sensation) The feel of the tube when touched with the fingers (moist, smooth, soft) was used as an index of tactile sensation, and 10 people were asked to give a sensory evaluation on a 5-point scale as shown below. An average score of 3 or more was marked as ○, and an average score of less than 3 was marked as ×.

[0201] (tensile properties) Tensile tests were carried out in accordance with JIS K6251 using a tensile testing machine (Minebea, Tg-5kN) with a No. 3 dumbbell and a crosshead speed of 500 mm / min. The modulus at 100% elongation (100% Mo.), tensile strength, and elongation at break were measured.

[0202] (forceps) The tube was closed with medical tube forceps at 23°C for 24 hours, and then the forceps were removed and the time until the inside of the tube recovered its shape and was released was measured, which was used as an index of clampability.

[0203] (stickiness) The stress when the tube was peeled off from the roll on which it was formed and wound was measured using a digital force gauge (Imada Co., Ltd., ZTS-100N).

[0204] (transparency) The hydrogenated copolymer (a) and other materials used for the tube were hot-pressed at 200°C to form a sheet (0.5 mm thick). The haze value (%) of the sheet was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., NDH-1001DP) and used as an index of transparency. The obtained haze value was evaluated according to the following criteria. ○: Haze value is less than 10% ×: Haze value is 10% or more

[0205] (viscoelasticity measurement) The hydrogenated copolymer (a) and other materials used for the tube were heat-pressed at 200°C to form a sheet (thickness 2.0 mm). The measurement sample was set in a torsion-type geometry using a viscoelasticity measurement analyzer (device name: ARES-G2, manufactured by TA Instruments), and the dynamic viscoelasticity spectrum was measured under the following conditions to obtain the peak temperature (i.e., the temperature at which the peak occurs in the tanδ vs. temperature curve) of the loss factor (tanδ) (i.e., the ratio of the loss modulus (G") to the storage modulus (G')). Measurement sample size: thickness 2.0 mm, width 12.6 mm, length 40 mm Effective measurement length: 22 mm Strain: 0.5% Frequency: 1Hz Measurement temperature range: -100 to 150°C

[0206] 〔tube〕 As can be seen from Tables 2 and 3, the tube of the present embodiment made of the hydrogenated copolymer (a) of the present embodiment and other materials has excellent transparency, flexibility, kink resistance, solvent adhesion, and a good balance of each property at a high level.

[0207] Figure 1 (loss tangent (tanδ)) and Figure 2 (storage modulus) show the viscoelastic curves of hydrogenated copolymers (a) a-1 and a-2, and Asahi Kasei's "Tuftec (registered trademark) H1043" used in Table 3. By combining the hydrogenated copolymers and other components in specific proportions, the tanδ curve can be controlled, achieving a good balance of the properties required for the tube. [Industrial Applicability]

[0208] The tube of this embodiment has industrial applicability for a variety of tubular molded products, including automobile parts, civil engineering and construction applications, home appliance parts, food processing parts, medical parts, sporting goods, miscellaneous goods, and stationery.

Claims

1. The present invention relates to a hydrogenated copolymer (a) that contains at least one polymer block A1 mainly composed of a vinyl aromatic compound and at least one polymer block A2 containing a vinyl aromatic compound and a conjugated diene compound, and that satisfies the following (1) to (3): containing erucamide, zinc stearate, and ethylene bisstearamide in a mass ratio of 0.20:0.15:0.15; tube. (1) The content of all vinyl aromatic compounds contained in the hydrogenated copolymer (a) is 30% by mass to 90% by mass based on the mass of the hydrogenated copolymer (a). (2) The content of the polymer block A1 is 1% by mass to 40% by mass based on the mass of the hydrogenated copolymer (a). (3) The content of the vinyl aromatic compound contained in the polymer block A2 is 25% by mass to 80% by mass based on the mass of the polymer block A2.

2. 2. The tube according to claim 1, wherein the content of the polymer block A1 is 5 to 35 mass % based on the mass of the hydrogenated copolymer (a).

3. 3. The tube according to claim 1, which does not contain a polyolefin resin.

Images