Manufacturing method of medical rubber article

Abstract

To provide a manufacturing method of a medical rubber article with reduced surface friction coefficient and adhesiveness.SOLUTION: A manufacturing method of a medical rubber article includes: a step of irradiating, with ultraviolet light, a cured product of a medical rubber composition including: a base material polymer including halogenation butyl rubber (a), and a particulate polyolefin resin (b).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for manufacturing medical rubber articles, and more particularly to a technique for reducing the coefficient of friction and adhesiveness on the surface of medical rubber articles.

Background Art

[0002] Halogenated butyl rubber, which has excellent gas barrier properties, is used for medical rubber articles. Since halogenated butyl rubber has a small amount of double bonds that can be vulcanized, the surface of the rubber article after vulcanization has adhesiveness (high tack value). Therefore, the slidability is poor, and there is a problem that rubber parts stick to each other when stored for a long time. For the purpose of imparting high slidability and reducing frictional resistance, silicone oil is applied to the surface of the rubber article after vulcanization, or it is laminated with a fluororesin film.

[0003] On the other hand, there is a surface modification method of irradiating a polymer material with ultraviolet rays in order to improve the properties of the polymer material surface.

[0004] For example, in Patent Document 1, a material made of a polymer having a -CH2- bond in the side chain or main chain is irradiated with ultraviolet rays having a wavelength of 160 to 310 nm in an inert atmosphere, and then the material is irradiated with ultraviolet rays having a wavelength of 200 nm or less in an oxidizing atmosphere, thereby a surface modification method of a material for making the wettability of the material surface uniform is disclosed.

[0005] In Patent Document 2, a vinyl compound represented by the general formula (1) R-CH=CH2 (wherein R represents an alkyl group having 6 or more carbon atoms) is brought into contact with the surface of a polymer material substrate (however, excluding a cloth substrate), and ultraviolet rays are irradiated, thereby a surface treatment method of a polymer material substrate for imparting water repellency to the surface of the polymer material substrate is disclosed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] To improve slidability, silicone oil is applied to the surface of medical rubber articles, or they are laminated with fluororesin films. However, when medical rubber articles coated with silicone oil come into contact with biopharmaceuticals, there is a risk of protein aggregation due to silicone particles. Therefore, medical rubber articles coated with silicone oil cannot be used for medical supplies that use biopharmaceuticals. In particular, for the plunger stoppers of prefilled syringes, the need for silicone oil-free (SOF) is increasing.

[0008] In addition, laminated medical rubber articles laminated with fluororesin films such as polytetrafluoroethylene (PTFE) films have an elastic modulus of the PTFE film 100 times higher than that of rubber, and there is a tendency for the sealing performance to decrease as a plunger stopper of a prefilled syringe. Furthermore, since the PTFE film does not decompose, there are potential risks to the environment and human health, and in the future, the PTFE film may not be usable in response to PFAS (perfluoroalkyl compounds or polyfluoroalkyl compounds) regulations.

[0009] As described above, in response to SOF and PFAS regulations, there is a need for a method to reduce the coefficient of friction and adhesiveness on the surface of medical rubber articles without using silicone oil or fluororesin films.

[0010] The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing a novel medical rubber article in which the coefficient of friction and adhesiveness of the surface are reduced.

Means for Solving the Problems

[0011] The manufacturing method of the medical rubber article of the present invention includes a step of irradiating ultraviolet rays to a cured product of a medical rubber composition containing (a) a base polymer containing halogenated butyl rubber and (b) a particulate polyolefin resin. The inventor has completed the present invention by finding that when ultraviolet rays are irradiated to a cured product of a medical rubber composition containing (a) a base polymer containing halogenated butyl rubber and (b) a particulate polyolefin resin, the surface of the cured product is greatly modified to have a low friction coefficient and low adhesiveness (tack value is almost zero).

Advantages of the Invention

[0012] By using the manufacturing method of the medical rubber article of the present invention, a medical rubber article with a reduced surface friction coefficient and adhesiveness can be obtained.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

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Figure 6

Modes for Carrying Out the Invention

[0014] The manufacturing method of the medical rubber article of the present invention includes a step of irradiating ultraviolet rays to a cured product of a medical rubber composition containing (a) a base polymer containing halogenated butyl rubber and (b) a particulate polyolefin resin (hereinafter, may be simply referred to as "ultraviolet irradiation step").

[0015] The cured product of the medical rubber composition used in the manufacturing method of the present invention is obtained by vulcanizing a medical rubber composition containing (a) a base polymer containing halogenated butyl rubber and (b) a particulate polyolefin resin. First, the medical rubber composition will be described.

[0016] <Medical rubber composition> [(a) Base polymer] (a) The base polymer contains halogenated butyl rubber. In the ultraviolet irradiation step, a crosslinking reaction occurs in the halogenated butyl rubber, and the elastic modulus of the entire (a) base polymer increases on the rubber surface, making it difficult to deform. As a result, the medical rubber article obtained by the manufacturing method of the present invention has a reduced true contact area and a reduced friction coefficient at the contact surface with other articles.

[0017] (a) Examples of the halogenated butyl rubber contained in the base polymer include chlorinated butyl rubber, brominated butyl rubber, and brominated products of copolymers of isobutylene and p-methylstyrene. These halogenated butyl rubbers may be used alone or in combination of two or more. As the halogenated butyl rubber, chlorinated butyl rubber or brominated butyl rubber is preferable. The chlorinated butyl rubber or brominated butyl rubber is obtained by adding or substituting chlorine or bromine to the isoprene structural part in butyl rubber, specifically, the double bond and / or the carbon atom adjacent to the double bond. Note that butyl rubber is a copolymer obtained by polymerizing isobutylene and a small amount of isoprene. Note that the halogenated butyl rubber is preferably solid at normal temperature (23°C).

[0018] The halogen content in the halogenated butyl rubber is preferably 0.5% by mass or more, preferably 1% by mass or more, more preferably 1.2% by mass or more, preferably 5% by mass or less, more preferably 4% by mass or less, and even more preferably 3% by mass or less.

[0019] (a) When the base polymer contains chlorinated butyl rubber or brominated butyl rubber as the halogenated butyl rubber, a crosslinking reaction occurs at the chlorinated or brominated isoprene moiety in the ultraviolet irradiation step. (a) When the base polymer contains brominated isobutylene-paramethylstyrene copolymer rubber (BIMS) as the halogenated butyl rubber, a crosslinking reaction occurs at the brominated paramethylstyrene moiety in the ultraviolet irradiation step.

[0020] Specific examples of the chlorinated butyl rubber include, for example, Exxon (registered trademark) Chlorobutyl 1066 manufactured by ExxonMobil [halogen content rate: 1.25 wt%, Mooney viscosity: 38 ML 1+8 (125 °C), specific gravity: 0.92], Exxon Chlorobutyl 5066 [halogen content rate: 1.50 wt%, Mooney viscosity: 40 ML 1+8 (125 °C), specific gravity: 0.92]; and at least one such as LANXESS X_BUTYL (registered trademark) CB1240 manufactured by LANXESS.

[0021] Specific examples of the brominated butyl rubber include, for example, Exxon Bromobutyl 2211 manufactured by ExxonMobil [halogen content rate: 2.0 wt%, Mooney viscosity: 32 ML 1+8 (125 °C), specific gravity: 0.93], Exxon Bromobutyl 2222 [halogen content rate: 2.0 wt%, Mooney viscosity: 32 ML 1+8 (125 °C), specific gravity: 0.93], Exxon Bromobutyl 2235 [halogen content rate: 2.1 wt%, Mooney viscosity: 39 ML 1+8(125 °C), specific gravity: 0.93], Exxon Bromobutyl 2244 [halogen content rate: 2.0 wt%, Mooney viscosity: 46 ML 1+8 (125 °C), specific gravity: 0.93], Exxon Bromobutyl 2255 [halogen content rate: 2.1 wt%, Mooney viscosity: 46 ML 1+8 (125 °C), specific gravity: 0.93], Exxon Bromobutyl 6222 [halogen content rate: 2.4 wt%, Mooney viscosity: 32 ML 1+8 (125 °C), specific gravity: 0.93], Exxon Bromobutyl 7211 [halogen content rate: 2.0 wt%, Mooney viscosity: 32 ML 1+8 (125 °C), specific gravity: 0.93], Exxon Bromobutyl 7244 [halogen content rate: 2.1 wt%, Mooney viscosity: 46 ML 1+8 (125 °C), specific gravity: 0.93]; at least one such as LANXESS X_BUTYL BBX2 manufactured by LANXESS may be mentioned.

[0022] (a) The base polymer may contain a rubber component other than the halogenated butyl rubber. Examples of other rubber components include, for example, butyl rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, natural rubber, chloroprene rubber, nitrile rubbers such as acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, norbornene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, acrylic rubber, ethylene acrylate rubber, fluororubber, chlorosulfonated polyethylene rubber, epichlorohydrin rubber, silicone rubber, urethane rubber, polysulfide rubber, phosphazen rubber, or 1,2-polybutadiene, etc. These may be used alone or in combination of two or more.

[0023] When using other rubber components, (a) the content rate of the halogenated butyl rubber in the base polymer is preferably 90 mass% or more, more preferably 95 mass% or more, and still more preferably 98 mass% or more. Also, (a) it is a preferred embodiment that the base polymer consists only of the halogenated butyl rubber.

[0024] [(b) particulate polyolefin resin] (b) The particulate polyolefin resin is resin particles composed of a polyolefin resin.

[0025] (b) Since the particulate polyolefin resin hardly absorbs ultraviolet rays (especially ultraviolet rays with a wavelength of 160 nm or more), it does not react in the ultraviolet irradiation step and is exposed on the surface of the cured product of the medical rubber composition. As a result, in the medical rubber article obtained by the production method of the present invention, the true contact area further decreases at the contact surface with other parts, so that it is possible to further reduce the friction coefficient on the surface of the rubber part.

[0026] The polyolefin resin is not particularly limited. For example, polyethylene resins such as linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), ultra-high molecular weight polyethylene (UHMWPE), and copolymers of ethylene and α-olefins (for example, α-olefins having 3 to 8 carbon atoms); polypropylene (PP), propylene-ethylene copolymers, polypropylene resins such as copolymers of propylene and α-olefins (for example, α-olefins having 4 to 8 carbon atoms); and olefins such as polybutene, polypentene, and polymethylpentene (for example, olefins having 4 to 8 carbon atoms) alone or copolymers. These can be used alone or in combination of two or more. The polyethylene resin means a resin in which the mass ratio of the repeating unit derived from ethylene in the resin is more than 50% by mass (preferably 70% by mass or more, more preferably 90% by mass or more), and the polypropylene resin means a resin in which the mass ratio of the repeating unit derived from propylene in the resin is more than 50% by mass (preferably 70% by mass or more, more preferably 90% by mass or more). Among these, from the viewpoint of more favorably obtaining the effects of the present invention, polyethylene resins are preferred, low-density polyethylene (LDPE), high-density polyethylene (HDPE), and ultra-high molecular weight polyethylene (UHMWPE) are more preferred, and ultra-high molecular weight polyethylene (UHMWPE) is even more preferred.

[0027] The density (kg / m 3 ) of the high-density polyethylene is preferably 930 kg / m 3 to 960 kg / m 3 and more preferably 930 kg / m 3 to 950 kg / m 3 The density (kg / m 3 ) of the low-density polyethylene is not particularly limited, but is preferably 910 kg / m 3 to 925 kg / m 3 and more preferably 910 kg / m 3 to 920 kg / m 3 .

[0028] (b) The volume average particle diameter of the particulate polyolefin resin is preferably 200 μm or less, more preferably 160 μm or less, and even more preferably 120 μm or less. Also, (b) the volume average particle diameter of the particulate polyolefin resin is preferably 10 μm or more, more preferably 15 μm or more, and even more preferably 20 μm or more. This is because it becomes easier to uniformly mix and disperse within the polymer within the above range. Incidentally, (b) the volume average particle diameter of the particulate polyolefin resin can be measured, for example, by the Coulter-Counter method.

[0029] In the present invention, it is particularly preferable to use ultra-high molecular weight polyethylene (UHMWPE) as (b) the particulate polyolefin resin. Ultra-high molecular weight polyethylene is generally polyethylene having an average molecular weight of 500,000 or more.

[0030] The viscosity average molecular weight of the ultra-high molecular weight polyethylene (UHMWPE) is not particularly limited, but is preferably 500,000 or more, more preferably 1,000,000 or more, even more preferably 1,500,000 or more, preferably 8,000,000 or less, more preferably 7,000,000 or less, and even more preferably 6,000,000 or less.

[0031] The viscosity average molecular weight of the ultra-high molecular weight polyethylene (UHMWPE) is measured by measuring the intrinsic viscosity [η] in a decalin solvent at 135°C, and the value calculated based on the formula: Mν = k[η] α (where Mν is the viscosity average molecular weight, and k and α are constants). The intrinsic viscosity is measured by a method conforming to JIS K7367-3 (1999).

[0032] The density of the ultra-high molecular weight polyethylene (UHMWPE) is not particularly limited, but it is preferably 930 kg / m 3 or more, more preferably 932 kg / m 3 or more, still more preferably 934 kg / m 3 or more, and preferably 945 kg / m 3 or less, more preferably 943 kg / m 3 or less, still more preferably 940 kg / m 3 or less is even more preferable.

[0033] The melting point of the ultra-high molecular weight polyethylene is preferably 120°C or higher, more preferably 125°C or higher, and still more preferably 130°C or higher. The melting point of the ultra-high molecular weight polyethylene is measured in accordance with ATSM-D3418.

[0034] Specific examples of the ultra-high molecular weight polyethylene (UHMWPE) include, for example, Mipiron (registered trademark) PM-200 manufactured by Mitsui Chemicals [viscosity average molecular weight: 1.8 million, volume average particle diameter (Coulter-Counter method): 10 μm, density: 938 kg / m 3 , XM-220 [viscosity average molecular weight: 2 million, volume average particle diameter (Coulter-Counter method): 30 μm, density: 937 kg / m 3 , XM-221U [viscosity average molecular weight: 2 million, volume average particle diameter (Coulter-Counter method): 25 μm, density: 937 kg / m 3 , XM-330 [viscosity average molecular weight: 2 million, volume average particle diameter (Coulter-Counter method): 65 μm, density: 937 kg / m 3 , etc.

[0035] (b) The content of the particulate polyolefin resin is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, still more preferably 20 parts by mass or more, preferably 100 parts by mass or less, more preferably 80 parts by mass or less, and still more preferably 70 parts by mass or less, based on 100 parts by mass of the (a) base polymer component. If the content of the particulate polyolefin resin in (b) is 5 parts by mass or more, the effect of reducing the friction coefficient by the particulate polyolefin resin in (b) is further improved. If it is 100 parts by mass or less, it is easier to uniformly mix and disperse in the polymer.

[0036] [Other components] The medical rubber composition preferably contains (c) a crosslinking agent. The (c) crosslinking agent is compounded to crosslink the halogenated butyl rubber component contained in the (a) base polymer. The (c) crosslinking agent is not particularly limited as long as it is a crosslinking agent capable of crosslinking the halogenated butyl rubber. Examples of the (c) crosslinking agent include sulfur, metal oxides, resin crosslinking agents, organic peroxides, triazine derivatives, etc., and these can be used alone or in combination of two or more.

[0037] Examples of sulfur used as the crosslinking agent include insoluble sulfur, powdered sulfur, fine powdered sulfur, precipitated sulfur, colloidal sulfur, sulfur chloride, etc.

[0038] Examples of metal oxides used as the crosslinking agent include magnesium oxide, calcium oxide, zinc oxide, copper oxide, etc.

[0039] Examples of resin crosslinking agents include alkylphenol formaldehyde resins such as alkylphenol formaldehyde resins, thermoreactive phenol resins, phenol dialcohol resins, bisphenol resins, and thermoreactive bromomethylalkylated phenol resins.

[0040] Specific examples of the organic peroxide include dialkyl peroxide, peroxy ester, peroxy ketal, hydroperoxide, etc. Examples of the dialkyl peroxide include di(2-t-butylperoxyisopropyl)benzene, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylcumyl peroxide, di-t-hexyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, etc. Examples of the peroxy ester include t-butyl peroxymaleate, t-butyl peroxy-3,3,5-trimethylcyclohexanoate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butyl peroxyacetate, t-butyl peroxybenzoate, etc. Examples of the peroxy ketal include 1,1-di(t-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-di(t-hexylperoxy)cyclohexane, 1,1-di(t-butylperoxy)-2-methylcyclohexane, 1,1-di(t-butylperoxy)cyclohexane, 2,2-di(t-butylperoxy)butane, n-butyl-4,4-di(t-butylperoxy)valerate, 2,2-di(4,4-di(t-butylperoxy)cyclohexyl)propane, etc. Examples of the hydroperoxide include p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, etc. These organic peroxides may be used alone or in combination of two or more.

[0041] Examples of the triazine derivative used as the crosslinking agent include compounds represented by the general formula (1).

[0042] [Chemical formula]

[0043] [wherein, R is -SH, -OR 1 , -SR 2 , -NHR 3 or -NR 4 R 5 (R 1 , R 2 , R 3 , R 4 and R 5 each represents an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkylaryl group or a cycloalkyl group. R 4 and R 5 may be the same or different. ). M 1 and M 2 are H, Na, Li, K, 1 / 2Mg, 1 / 2Ba, 1 / 2Ca, an aliphatic primary amine, a secondary amine or a tertiary amine, a quaternary ammonium salt or a phosphonium salt. M 1 and M 2 may be the same or different. ]

[0044] In the general formula (1), examples of the alkyl group include alkyl groups having 1 to 12 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, tert-pentyl group, n-hexyl group, 1,1-dimethylpropyl group, octyl group, isooctyl group, 2-ethylhexyl group, decyl group, or dodecyl group. Examples of the alkenyl group include alkenyl groups having 1 to 12 carbon atoms such as vinyl group, allyl group, 1-propenyl group, isopropenyl group, 2-butenyl group, 1,3-butadienyl group, or 2-pentenyl group. Examples of the aryl group include monocyclic or condensed polycyclic aromatic hydrocarbon groups, and aryl groups having 6 to 14 carbon atoms such as phenyl group, naphthyl group, anthryl group, phenanthryl group or acenaphthylenyl group, etc. Examples of the aralkyl group include aralkyl groups having 7 to 19 carbon atoms such as benzyl group, phenethyl group, diphenylmethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 2,2-diphenylethyl group, 3-phenylpropyl group, 4-phenylbutyl group, 5-phenylpentyl group, 2-biphenylylmethyl group, 3-biphenylylmethyl group or 4-biphenylylmethyl group. Examples of the alkylaryl group include alkylaryl groups having 7 to 19 carbon atoms such as tolyl group, xylyl group or octylphenyl group. Examples of the cycloalkyl group include cycloalkyl groups having 3 to 9 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group or cyclononyl group, etc.

[0045] Specific examples of the triazine derivative represented by the general formula (1) include, for example, 2,4,6-trimercapto-s-triazine, 2-methylamino-4,6-dimercapto-s-triazine, 2-(n-butylamino)-4,6-dimercapto-s-triazine, 2-octylamino-4,6-dimercapto-s-triazine, 2-propylamino-4,6-dimercapto-s-triazine, 2-diallylamino-4,6-dimercapto-s-triazine, 2-dimethylamino-4,6-dimercapto-s-triazine, 2-dibutylamino-4,6-dimercapto-s-triazine, 2-di(iso-butylamino)-4,6-dimercapto-s-triazine, 2-dipropylamino-4,6-dimercapto-s-triazine, 2-di(2-ethylhexyl)amino-4,6-dimercapto-s-triazine, 2-dioleylamino-4,6-dimercapto-s-triazine, 2-laurylamino-4,6-dimercapto-s-triazine or 2-anilino-4,6-dimercapto-s-triazine, or sodium salts or disodium salts thereof.

[0046] Among these, 2,4,6-trimercapto-s-triazine, 2-dialkylamino-4,6-dimercapto-s-triazine, and 2-anilino-4,6-dimercapto-s-triazine are preferable, and 2-dibutylamino-4,6-dimercapto-s-triazine is particularly preferable in terms of easy availability.

[0047] In addition, examples of the triazine derivative include one or more of 6-[bis(2-ethylhexyl)amino]-1,3,5-triazine-2,4-dithiol, 6-diisobutylamino-1,3,5-triazine-2,4-dithiol, 6-dibutylamino-1,3,5-triazine-2,4-dithiol, 6-dibutylamino-1,3,5-triazine-2,4-dithiol monosodium, 6-anilino-1,3,5-triazine-2,4-dithiol, 1,3,5-triazine-2,4,6-trithiol, etc.

[0048] In the medical rubber composition used in the present invention, as the triazine derivative, one kind may be used alone, or two or more kinds may be used in combination.

[0049] Since the chlorinated butyl rubber and the brominated butyl rubber have different crosslinking mechanisms, it is preferable to select and use the crosslinking component optimal for crosslinking. When the medical rubber composition contains chlorinated butyl rubber as the halogenated butyl rubber, it is preferable to contain a triazine derivative as the (c) crosslinking agent. Further, when the medical rubber composition contains brominated butyl rubber as the halogenated butyl rubber, it is preferable to contain a metal oxide as the (c) crosslinking agent.

[0050] The content of the (c) crosslinking agent in the medical rubber composition is preferably 0.2 parts by mass or more, more preferably 0.4 parts by mass or more, still more preferably 0.6 parts by mass or more, preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and still more preferably 10 parts by mass or less with respect to 100 parts by mass of the (a) base polymer component. If the content of the (c) crosslinking agent is within the above range, it is because a rubber having good rubber physical properties (hardness, tensile strength, Cset) and processability (less scorching) can be obtained.

[0051] When chlorinated butyl rubber is used as the halogenated butyl rubber and a triazine derivative is used as the (c) crosslinking agent, the content of the (c) crosslinking agent in the medical rubber composition is preferably 0.2 parts by mass or more, more preferably 0.4 parts by mass or more, still more preferably 0.6 parts by mass or more, preferably 4 parts by mass or less, more preferably 3 parts by mass or less, and still more preferably 2 parts by mass or less with respect to 100 parts by mass of the (a) base polymer component. If the content of the (c) crosslinking agent is within the above range, it is because a rubber having good rubber physical properties (hardness, tensile strength, Cset) and processability (less scorching) can be obtained.

[0052] As the halogenated butyl rubber, brominated butyl rubber is used. When a metal oxide is used as the (c) crosslinking agent, the content of the (c) crosslinking agent in the medical rubber composition is preferably 1 part by mass or more, more preferably 1.5 parts by mass or more, further preferably 2 parts by mass or more, preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and further preferably 10 parts by mass or less with respect to 100 parts by mass of the (a) base polymer component. If the content of the (c) crosslinking agent is within the above range, a rubber with good rubber physical properties (hardness, tensile strength, C set) and processability (less scorching) can be obtained.

[0053] The medical rubber composition preferably does not contain a vulcanization accelerator. This is because the vulcanization accelerator may remain in the final rubber product and elute into the chemical solution in a syringe or the like. Examples of the vulcanization accelerator include guanidine-based accelerators (e.g., diphenylguanidine), thiuram-based accelerators (e.g., tetramethylthiuram disulfide, tetramethylthiuram monosulfide), dithiocarbamate-based accelerators (e.g., zinc dimethyldithiocarbamate), thiazole-based accelerators (e.g., 2-mercaptobenzothiazole, dibenzothiazyl disulfide), and sulfenamide-based accelerators (N-cyclohexyl-2-benzothiazole sulfenamide, N-t-butyl-2-benzothiazole sulfenamide).

[0054] The medical rubber composition may further contain a (d) acid acceptor. The (d) acid acceptor functions to absorb chlorine-based gases and bromine-based gases generated during the crosslinking of the halogenated butyl rubber and prevent the occurrence of crosslinking inhibition and the like caused by these gases. In addition, the (d) acid acceptor functions as a scorch inhibitor during the crosslinking of the halogenated butyl rubber and also functions to prevent an increase in the compression set of the medical rubber parts.

[0055] Examples of the (d) acid acceptor include hydrotalcite, metal oxides, metal hydroxides, etc. Examples of hydrotalcite include Mg 4.5 Al2(OH) 13CO3·3.5H2O, Mg 4.5 Al2(OH) 13 CO3, Mg4Al2(OH) 12 CO3·3.5H2O, Mg6Al2(OH) 16 CO3·4H2O, Mg5Al2(OH) 14 CO3·4H2O, Mg3Al2(OH) 10 Examples include Mg - Al - based hydrotalcites such as CO3·3.5H2O, and the like. Examples of the metal oxide include magnesium oxide, calcium oxide, zinc oxide, and the like. Examples of the metal hydroxide include calcium hydroxide, and the like. These acid acceptors may be used alone or in combination of two or more. Note that the metal oxide used as the crosslinking agent described above can also function as an acid acceptor.

[0056] (d) The content of the acid acceptor is preferably 0.5 part by mass or more, more preferably 1 part by mass or more, preferably 15 parts by mass or less, and more preferably 10 parts by mass or less with respect to 100 parts by mass of the base polymer component (a). If the content of the acid acceptor is within the above range, generation of rust on molds and the like can be suppressed, and the problem that the raw material itself becomes white spot foreign matter can be reduced.

[0057] The medical rubber composition may further contain a filler. Examples of the filler include inorganic fillers such as clay and talc. Among these, the filler is preferably an inorganic filler, and more preferably clay or talc. The filler functions to adjust the rubber hardness of medical rubber parts and also functions to reduce the production cost of medical rubber parts as a bulking agent.

[0058] Examples of the clay include fired clay and kaolin clay. Specific examples of the clay include, for example, SILLITIN (registered trademark) Z manufactured by HOFFMANN MINERAL, SATINTONE (registered trademark) W manufactured by ENGELHARD, NN kaolin clay manufactured by Tsuchiya Kaolin Industry Co., Ltd., PoleStar200R manufactured by Imerys Specialties Japan, and the like.

[0059] Specific examples of the talc include, for example, Hytron A manufactured by Takehara Chemical Industry Co., Ltd., MICRO ACE (registered trademark) K-1 manufactured by Nippon Talc Co., Ltd., Mistron (registered trademark) Vapor manufactured by Imerys Specialties Japan, and the like.

[0060] The content of the filler in the medical rubber composition is preferably set appropriately according to the rubber hardness and the like of the intended medical rubber article. The content of the filler in the medical rubber composition is, for example, preferably 5 parts by mass or more, more preferably 10 parts by mass or more, still more preferably 20 parts by mass or more, preferably 200 parts by mass or less, more preferably 150 parts by mass or less, and still more preferably 100 parts by mass or less with respect to 100 parts by mass of the base polymer component.

[0061] The medical rubber composition may further be blended with a colorant such as titanium oxide and carbon black, a lubricant such as stearic acid, a processing aid, polyethylene glycol as a crosslinking activator, a process oil, and the like in appropriate proportions.

[0062] [Preparation of Medical Rubber Composition] The medical rubber composition is obtained by kneading (a) a base polymer, (b) a particulate polyolefin resin, and other compounding materials added as necessary. Kneading can be performed using, for example, an open roll, a closed kneader, or the like. The kneaded product is preferably formed into a ribbon shape, a sheet shape, a pellet shape, or the like, and more preferably formed into a sheet shape.

[0063] The kneading of (a) the base polymer and (b) the particulate polyolefin resin is preferably carried out at a temperature below the melting point of (b) the particulate polyolefin resin.

[0064] <Hardened product of the medical rubber composition> The hardened product of the medical rubber composition of the present invention is obtained by vulcanizing (crosslinking) the medical rubber composition. By press-molding a ribbon-shaped, sheet-shaped, or pellet-shaped kneaded product, a hardened product of the medical rubber composition having a desired shape can be obtained. The crosslinking reaction of the medical rubber composition proceeds during pressing. The molding temperature is preferably, for example, 130°C or higher, more preferably 140°C or higher, preferably 200°C or lower, and more preferably 190°C or lower. The molding time is preferably 2 minutes or longer, more preferably 3 minutes or longer, preferably 60 minutes or shorter, and more preferably 30 minutes or shorter. The molding pressure is preferably 0.1 MPa or higher, more preferably 0.2 MPa or higher, preferably 10 MPa or lower, and more preferably 8 MPa or lower.

[0065] <UV irradiation step> The method for producing a medical rubber article of the present invention includes a step of irradiating the hardened product of the medical rubber composition with ultraviolet rays (UV irradiation step). The hardened product of the medical rubber composition to be irradiated with ultraviolet rays may be in the shape of the final medical rubber article or a preform before being formed into the shape of the final medical rubber article.

[0066] The method for irradiating the hardened product of the medical rubber composition with ultraviolet rays is not particularly limited, and examples thereof include irradiating the surface of the hardened product of the medical rubber composition using a light source that emits ultraviolet rays.

[0067] The wavelength of the ultraviolet light is preferably 160 nm or more, more preferably 165 nm or more, and even more preferably 170 nm or more. If the wavelength of the ultraviolet light is 160 nm or more, the (b) particulate polyolefin resin hardly absorbs the ultraviolet light of this wavelength, so it does not react even when irradiated with ultraviolet light and is scattered on the surface of the cured product of the medical rubber composition. Further, the upper limit of the wavelength of the ultraviolet light is not particularly limited, but it is preferably 380 nm or less, more preferably 300 nm or less, and even more preferably 200 nm or less. If the wavelength of the ultraviolet light is 380 nm or less, the energy of the ultraviolet light becomes high, the crosslinking efficiency of the halogenated butyl rubber becomes high, and it becomes difficult to deform. Further, the low molecular components that contribute to the surface tackiness of the cured product of the medical rubber composition are decomposed and evaporated by the high-energy ultraviolet light, and low tackiness can be realized. Furthermore, due to the evaporation of the low molecular components, the (b) particulate polyolefin resin is exposed on the surface of the cured product, and the surface of the cured product becomes rough, so that the coefficient of friction can be further reduced. Among these, vacuum ultraviolet light having a wavelength of 200 nm or less is particularly preferable from the viewpoint of obtaining the effects of the present invention more favorably.

[0068] The light source that emits the ultraviolet rays is not particularly limited as long as it can emit ultraviolet rays in the above wavelength range. For example, a low-pressure mercury lamp, a high-pressure mercury lamp, an excimer lamp, etc. are used. In particular, an excimer lamp is preferable because it has strong energy and the surface can be modified in a relatively short time. The excimer lamp emits ultraviolet rays with different wavelengths depending on the type of discharge gas used. For example, when xenon (Xe2) is used, it emits ultraviolet rays with a central wavelength of 172 nm, when xenon chloride (XeCl) is used, it emits ultraviolet rays with a central wavelength of 308 nm, when xenon bromide (XeBr) is used, it emits ultraviolet rays with a central wavelength of 283 nm, when xenon iodide (XeI) is used, it emits ultraviolet rays with a central wavelength of 253 nm, when argon fluoride (ArF) is used, it emits ultraviolet rays with a central wavelength of 193 nm, when argon bromide (ArBr) is used, it emits ultraviolet rays with a central wavelength of 165 nm, when krypton chloride (KrCl) is used, it emits ultraviolet rays with a central wavelength of 222 nm, and when krypton bromide (KrBr) is used, it emits ultraviolet rays with a central wavelength of 207 nm (also called "excimer UV light"). In the present invention, an excimer lamp that emits vacuum ultraviolet rays with a central wavelength of 200 nm or less is preferable, and an excimer lamp using xenon (central wavelength: 172 nm) is particularly preferable.

[0069] In the ultraviolet irradiation step, the integrated illuminance on the cured product of the medical rubber composition is preferably 1000 mJ / cm 2 or more, more preferably 3000 mJ / cm 2 or more, and even more preferably 5000 mJ / cm 2 or more. If the integrated illuminance on the cured product of the medical rubber composition is 1000 mJ / cm 2 or more, the crosslinking of the halogenated butyl rubber is sufficiently carried out, and the low-molecular components that contribute to the surface tackiness of the cured product of the medical rubber composition are more easily decomposed. Also, the upper limit of the integrated illuminance on the cured product of the medical rubber composition is not particularly limited, but it is preferably 50000 mJ / cm 2 or less, more preferably 45000 mJ / cm 2 or less, and even more preferably 40000 mJ / cm 2 or less. If the integrated illuminance on the cured product of the medical rubber composition is 50000 mJ / cm 2This is because if the following conditions are met, a balance can be achieved between the lifespan of the irradiation equipment and the efficiency of surface modification. The cumulative illuminance on the cured product of the medical rubber composition refers to the total illuminance (arrival illuminance) of ultraviolet rays reaching the surface of the cured product of the medical rubber composition, and can be calculated by multiplying the intensity of the ultraviolet rays reaching the surface of the cured product of the medical rubber composition (arrival intensity) by the irradiation time of the ultraviolet rays.

[0070] The arrival intensity and irradiation time of the ultraviolet rays may be appropriately adjusted so that the cumulative illuminance is within the above-mentioned range. Usually, the arrival intensity of the ultraviolet rays is 10 mW / cm 2 / sec to 100 mW / cm 2 / sec, and the irradiation time is preferably 10 seconds to 5000 seconds. By setting the arrival intensity and irradiation time of the ultraviolet rays within these ranges, it is easier to obtain the cumulative illuminance within the above-mentioned range.

[0071] The distance between the surface of the cured product of the medical rubber composition and the light source (lamp) that emits ultraviolet rays is not particularly limited, but from the viewpoint of enhancing the uniformity of ultraviolet irradiation, it is preferably 1 mm to 20 mm.

[0072] In the present invention, by irradiating the cured product of the medical rubber composition with ultraviolet rays, the surface of the cured product can be greatly modified to have a low coefficient of friction and low adhesiveness.

[0073] The method for manufacturing a medical rubber article of the present invention may include a step of processing the cured product of the medical rubber composition into a predetermined shape, a step of washing, a step of sterilizing, and a step of drying. For example, from the cured product of the medical rubber composition after ultraviolet irradiation, unnecessary portions are cut and removed to form a predetermined shape, and then washed, sterilized, dried, and packaged to produce a medical rubber article. Note that cutting and removing unnecessary portions to form a predetermined shape may also be performed before irradiating the cured product of the medical rubber composition with ultraviolet rays.

[0074] The medical rubber article obtained by the production method of the present invention can achieve a low coefficient of friction and low adhesiveness without using silicone oil or resin films such as fluorine films. Therefore, the medical rubber article of the present invention can be suitably used as a medical rubber article that requires a low coefficient of friction and low adhesiveness while complying with SOF and PFAS regulations.

[0075] From the viewpoint of SOF compliance, it is preferable that the silicone oil is not applied to the medical rubber article obtained by the production method of the present invention. Examples of the silicone oil include dimethylpolysiloxane, methylphenylpolysiloxane, and modified products thereof. Further, from the viewpoint of PFAS regulation compliance, it is preferable that the fluorine-containing resin film is not laminated on the medical rubber article of the present invention. Examples of the fluorine-containing resin film include films made of polytetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene copolymer (ETFE), and modified products thereof.

[0076] Examples of the medical rubber article obtained by the production method of the present invention include rubber stoppers and seal members for containers for various drugs such as liquid preparations, powder preparations, and freeze-dried preparations, rubber stoppers for vacuum blood collection tubes, plunger stoppers (gaskets) for prefilled syringes, or sliding or sealing parts such as nozzle caps. Among these, medical rubber parts (for example, rubber stoppers and plunger stoppers) that require a low coefficient of friction and low adhesiveness are preferable, and plunger stoppers that require excellent slidability are particularly preferable.

[0077] Among these, the rubber stoppers and seal members including those for vials and infusion preparation containers are preferably represented by the durometer type A hardness (Shore A hardness) measured in accordance with the measurement method described in Japanese Industrial Standard JIS K6253-3:2012 "Vulcanized Rubber and Thermoplastic Rubber - Method for Determining Hardness - Part 3: Durometer Hardness" and are preferably 35 or more and preferably 60 or less.

[0078] Also, the gasket for the prefilled syringe, the sliding or sealing parts of the nozzle cap preferably have a Shore A hardness of 40 or more and preferably 70 or less.

[0079] The rubber hardness of the medical rubber article can be adjusted by changing the blending ratio of each raw material.

[0080] FIG. 1 is a diagram showing, in an exploded state, a medical syringe in which the medical rubber article of the present invention is used, that is, a syringe called a so-called prefillable syringe. In FIG. 1, the syringe 11 and the plunger stopper 13 are each shown with half in cross-section. The prefillable syringe 10 includes a cylindrical syringe 11, a plunger 12 that is combined with the syringe 11 and can reciprocate within the syringe 11, and a plunger stopper 13 attached to the tip of the plunger 12. The plunger stopper 13 is made of the surface-modified cured product of the present invention.

[0081] The plunger 12 is composed of, for example, a resin plate piece having a cross-section in the shape of a cross, and a head portion 18 to which the plunger stopper 13 is attached is provided at its tip. The head portion 18 is made of resin integrally formed with the plunger 12 and is machined into a male screw shape. The plunger stopper 13 has a substantially cylindrical shape with a short axis, and its front end surface has, for example, a blunt angled mountain shape with the axial center portion protruding. And a female screw-shaped fitting recess 15 is formed by being engraved axially from the rear end surface. The plunger stopper 13 is attached to the tip of the plunger 12 by screwing the head portion 18 of the plunger 12 into the fitting recess 15 of the plunger stopper 13.

[0082] FIG. 2 is a schematic cross-sectional view of a specific example of the medical rubber stopper 20 as the medical rubber article. FIG. 3 shows a state in which the opening 24b of the container 24 filled with the medicine is sealed with the medical rubber stopper 20.

[0083] The medical rubber stopper 20 is configured to include a top plate 21 and a stopper leg 22. The top plate 21 has a puncture portion 23 that enables a syringe injection needle to puncture and a flange portion 21b that contacts the upper edge surface 24a of the container opening of the medical container 24. The stopper leg 22 protrudes from the lower surface of the top plate 21 and is fitted into the medical container opening. Further, the stopper leg 22 has a substantially cylindrical shape and is provided with a notch 27. A nylon film layer 26 is provided on the top surface portion of the top plate 21 of the medical rubber stopper 20. By providing the nylon film layer 26 on the top surface portion of the medical rubber stopper 20, the mechanical transportability during pharmaceutical production can be ensured. Also, by providing the nylon film layer 26 on the top surface portion of the medical rubber stopper 20, the surface smoothness degree of the top surface portion can be increased, and the generation of needle puncture fragments can be prevented during the puncture of the injection needle.

[0084] In the aspect shown in FIG. 3, as the container 24, a vial for storing a lyophilized preparation is used. When the liquid pharmaceutical product accommodated in the container 24 is an injection solution, the injection needle of the syringe is stabbed into the puncture portion 23 of the top plate 21, and the injection solution is inhaled into the syringe without opening the medical rubber stopper 20. In this way, the reason for not opening the medical rubber stopper 20 is to avoid the mixing of foreign substances into the injection solution in the container 24.

[0085] On the top plate 21, a metal or resin cap 25 is provided that can cover the opening 24b of the container 24 and the medical rubber stopper 20. Sealing the medical rubber stopper 20 with the cap 25 including the opening 24b is to prevent mold from adhering to the puncture portion 23 where the injection needle of the syringe is stabbed and the mold from mixing into the injection solution from the injection needle. As the type of the cap 25, a flip-off cap, a pull-top cap, a clean cap, etc. can be used. When a large amount of injection solution is used, such as in a hospital, it is preferable to use a clean cap that can be opened with one hand and is easy to operate.

[0086] FIG. 4(a) is a cross-sectional view showing an example of a nozzle cap of a medical syringe and the nozzle of a syringe barrel to be covered therewith. FIG. 4(b) is a cross-sectional view showing a state where the nozzle cap is put on the nozzle. The nozzle cap 41 in this example is for a syringe 45 with a needle in which a needle 44 is embedded in advance in the nozzle 43 of a syringe barrel 42. The nozzle cap is integrally formed from the surface-modified cured product of the present invention. The nozzle cap includes a cylindrical portion 46 whose inner diameter D1 is slightly smaller than the outer diameter D2 of the nozzle 43, and a needle puncturing portion 47 connected to one end side (the upper end side in the figure) of the cylindrical portion 46. The needle puncturing portion 47 is formed in a columnar shape having an outer surface continuous with the cylindrical portion 46. An opening 48 is provided at the other end side (the lower end side in the figure) of the cylindrical portion 46 for inserting the nozzle 43 into the cylindrical portion 46 to cover the nozzle 43 with the nozzle cap 41.

[0087] FIG. 5 is an explanatory view showing an example of a vacuum blood collection tube. The vacuum blood collection tube 50 includes a bottomed tube 51 and a rubber stopper 53 that seals the opening of the bottomed tube 51. Such a rubber stopper 53 is made of the surface-modified cured product of the present invention. It is designed to be able to automatically collect blood by decompressing the inside of the blood collection tube.

Example

[0088] Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited by the following examples, and any changes and embodiments within the scope not departing from the gist of the present invention are all included in the scope of the present invention.

[0089] [Production of Medical Rubber Articles] The materials shown in Table 1 were kneaded at 60° C. for 20 minutes using an open roll to prepare a medical rubber composition. After crosslinking the obtained medical rubber composition under molding conditions of 170° C. for 15 minutes, it was punched out into a circular slab with a diameter of 28 mm and a thickness of 2 mm to obtain a test piece for ultraviolet irradiation (a cured product of the medical rubber composition). The test piece for ultraviolet irradiation was irradiated with vacuum ultraviolet rays (wavelength: 172 nm) so as to obtain the integrated illuminance shown in Table 1. Irradiation Conditions of Ultraviolet Rays · Irradiation device: Electrodeless excimer 172 nm irradiation device (manufactured by M.D. Com Co., Ltd.) · Distance between the surface of the hardened material and the lamp: 7 mm · Intensity of ultraviolet light reaching: 57.9 mW / cm 2 / sec

[0090]

Table 1

[0091] Details of the compounding materials used are as follows. Chlorinated butyl rubber: Exxon (registered trademark) Chlorobutyl 1066 manufactured by ExxonMobil (chlorine content rate: 1.25 wt%) General-purpose butyl rubber: Exxon (registered trademark) Butyl 268 manufactured by ExxonMobil (degree of unsaturation: 2.30 mol%) Ultra-high molecular weight polyethylene: Mipelon (registered trademark) XM-220 manufactured by Mitsui Chemicals (volume average particle diameter: 30 μm, viscosity average molecular weight: 2 million) Triazine derivative: Disnet DB manufactured by Sankyo Kasei Co., Ltd. Sulfur: Insoluble sulfur (Seimi OT) manufactured by Nippon Kouryū Kōgyō Co., Ltd. Zinc oxide: Active zinc white AZO manufactured by Shōdō Chemical Industry Co., Ltd. Magnesium oxide: Mag Surat 150s manufactured by Kyowa Chemical Industry Co., Ltd. Dithiocarbamate: Nocceler (registered trademark) ZTC manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0092] [Evaluation method] (1) Coefficient of friction ><Measurement of static coefficient of friction and kinetic coefficient of friction> Figure 6 is an explanatory diagram showing a method for measuring the coefficient of friction using a coefficient of static and kinetic friction measuring machine TL201 (manufactured by TAILAB) for the medical rubber article (circular slab with a thickness of 2 mm and a diameter of 28 mm after ultraviolet irradiation) manufactured above. The measurement sample 63 is fixed to the lower stage 64, and a 10 g weight 61 is placed on a dedicated probe with a SUS ball 62 having a diameter of 10 mm to bring the surface of the measurement sample 63 into contact with the SUS ball 62. Then, the stage 64 is moved in the direction of the arrow at a speed of 10 mm / second for a distance of 20 mm. The value obtained by dividing the frictional force F generated at that time by the load (vertical resistance) N was defined as the coefficient of friction μ. (μ = F / N) Note that the coefficient divided by the average vertical resistance N1 for a moving distance of 20 mm was defined as the coefficient of kinetic friction, and the coefficient divided by the maximum average vertical resistance N2 for a moving distance of 20 mm was defined as the coefficient of static friction. <Evaluation of Coefficient of Static Friction> The coefficient of static friction was evaluated according to the following evaluation criteria. ○: The coefficient of static friction is less than 1.50. ×: The coefficient of static friction is 1.50 or more. <Evaluation of Coefficient of Kinetic Friction> The coefficient of kinetic friction was evaluated according to the following evaluation criteria. ○: The coefficient of kinetic friction is less than 1.30. ×: The coefficient of kinetic friction is 1.30 or more.

[0093] (2) Adhesion Test <Measurement of Tack Value> Regarding the medical rubber article (circular slab with a thickness of 2 mm and a diameter of 28 mm after ultraviolet irradiation) manufactured above, using a testing machine EZ-SX (manufactured by Shimadzu Corporation), the medical rubber article was fixed to a dedicated jig on the lower side, the upper metal Φ10 mm SUS probe was pressed against the surface of the medical rubber article, and after reaching the set pressure (10 N), it was held for 10 seconds and then raised upward at a speed of 10 mm / second. The peak value of the adhesive force generated between the probe and the cured product of the rubber composition was defined as the tack value, n = 5 was measured, and the average value of n = 3 excluding the maximum and minimum values was defined as the tack value. <Evaluation of Adhesion> The adhesion was evaluated according to the following evaluation criteria. 〇: The tack value is 0.5 N or less. ×: Tack value is more than 0.5 N.

[0094] (3) Comprehensive evaluation 〇: Evaluation results of both the coefficient of friction and adhesiveness are 〇. ×: There is an × in either the evaluation result of the coefficient of friction or the evaluation result of adhesiveness.

[0095] The measurement results and evaluation results of the coefficient of friction and adhesiveness are shown in Table 1.

[0096] From Table 1, it can be seen that the medical rubber article obtained by the manufacturing method of the present invention has a reduced surface coefficient of friction and adhesiveness.

Industrial applicability

[0097] The surface modification method of the present invention can provide a medical rubber part with a reduced surface coefficient of friction and adhesiveness. The medical rubber part of the present invention can be suitably used as a medical rubber part that requires a low coefficient of friction and low adhesiveness (especially good slidability).

Explanation of reference numerals

[0098] 10: Syringe, 11: Barrel, 12: Plunger, 13: Gasket, 18: Head part, 20: Medical rubber stopper, 21: Top plate, 22: Stopper leg, 23: Puncture part, 24: Medical container, 26: Nylon film layer, 25: Cap, 41: Nozzle cap, 42: Injection cylinder, 43: Nozzle, 44: Needle, 45: Syringe with needle

[0099] A preferred embodiment (1) of the present invention is a method for manufacturing a medical rubber article, which includes a step of irradiating ultraviolet rays onto a cured product of a medical rubber composition containing (a) a base polymer containing halogenated butyl rubber and (b) a particulate polyolefin resin.

[0100] A preferred embodiment (2) of the present invention is a method for manufacturing a medical rubber article according to embodiment (1), wherein the halogenated butyl rubber is at least one selected from the group consisting of chlorinated butyl rubber, brominated butyl rubber, and brominated copolymer of isobutylene and p-methylstyrene.

[0101] A preferred embodiment (3) of the present invention is a method for manufacturing a medical rubber article according to embodiment (1) or (2), wherein the base polymer containing the halogenated butyl rubber consists only of the halogenated butyl rubber.

[0102] A preferred embodiment (4) of the present invention is a method for manufacturing a medical rubber article according to any one of embodiments (1) to (3), wherein the content of the particulate polyolefin resin is 5 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the base polymer containing the halogenated butyl rubber.

[0103] A preferred embodiment (5) of the present invention is a method for manufacturing a medical rubber article according to any one of embodiments (1) to (4), wherein the volume average particle diameter of the particulate polyolefin resin is 200 μm or less.

[0104] A preferred embodiment (6) of the present invention is a method for manufacturing a medical rubber article according to any one of embodiments (1) to (5), wherein the particulate polyolefin resin is at least one selected from the group consisting of ultra-high molecular weight polyethylene, high density polyethylene, and low density polyethylene.

[0105] A preferred embodiment (7) of the present invention is a method for manufacturing a medical rubber article according to any one of embodiments (1) to (6), wherein the wavelength of the ultraviolet light is 160 nm to 380 nm.

[0106] A preferred embodiment (8) of the present invention is a method for manufacturing a medical rubber article according to any one of embodiments (1) to (7), wherein the integrated illuminance on the cured product of the medical rubber composition is 1000 mJ / cm 2 or more.

[0107] A preferred embodiment (9) of the present invention is a method for manufacturing any one of the medical rubber articles of embodiments (1) to (8), wherein the medical rubber article is a rubber stopper for a vial, a cap for a syringe, a plunger stopper, or a rubber stopper for a vacuum blood collection tube.

Claims

1. A method for manufacturing a medical rubber article, comprising a step of irradiating with ultraviolet rays a cured product of a medical rubber composition containing (a) a base polymer containing a halogenated butyl rubber and (b) a particulate polyolefin resin.

2. The method for manufacturing a medical rubber article according to claim 1, wherein the halogenated butyl rubber is at least one selected from the group consisting of chlorinated butyl rubber, brominated butyl rubber, and brominated products of copolymers of isobutylene and p-methylstyrene.

3. The method for manufacturing a medical rubber article according to claim 1, wherein the base polymer containing the halogenated butyl rubber consists only of the halogenated butyl rubber.

4. The method for manufacturing a medical rubber article according to claim 1, wherein the content of the particulate polyolefin resin (b) is 5 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the base polymer (a) containing the halogenated butyl rubber.

5. The method for manufacturing a medical rubber article according to claim 1, wherein the volume average particle diameter of the particulate polyolefin resin (b) is 200 μm or less.

6. The method for manufacturing a medical rubber article according to claim 1, wherein the particulate polyolefin resin (b) is at least one selected from the group consisting of ultra-high molecular weight polyethylene, high density polyethylene, and low density polyethylene.

7. The method for manufacturing a medical rubber article according to claim 1, wherein the wavelength of the ultraviolet rays is 160 nm to 380 nm.

8. The integrated illuminance on the cured product of the medical rubber composition is 1000 mJ / cm ２ The method for manufacturing a medical rubber article according to claim 1, wherein the integrated illuminance is 1000 mJ / cm or more.

9. The medical rubber article is a rubber stopper for a vial, a cap for a syringe, a plunger stopper, or a rubber stopper for a vacuum blood collection tube. The method for manufacturing a medical rubber article according to any one of claims 1 to 8.

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