Method for producing medical rubber article

Abstract

[Problem] To provide a method for producing a medical rubber article in which the surface friction coefficient and tackiness are reduced. [Solution] This method for producing a medical rubber composition is characterized by comprising a step for 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.

Description

Method for manufacturing medical rubber articles

[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 adhesion of the surface of medical rubber articles.

[0002] Medical rubber products use halogenated butyl rubber, which has excellent gas barrier properties. Because halogenated butyl rubber has only a small amount of double bonds that can be vulcanized, the surface of the vulcanized rubber product is sticky (high tack value). This results in poor sliding properties, and furthermore, the rubber parts tend to stick together after long-term storage. To improve sliding properties and reduce frictional resistance, the surface of the vulcanized rubber product is coated with silicone oil or laminated with a fluororesin film.

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

[0004] For example, Patent Document 1 discloses a compound having a —CH ２ A method for modifying the surface of a material is disclosed, in which a material made of a polymer having - bonds is irradiated with ultraviolet light having a wavelength of 160 to 310 nm in an inert atmosphere, and then the material is irradiated with ultraviolet light having a wavelength of 200 nm or less in an oxidizing atmosphere, thereby making the wettability of the surface of the material uniform.

[0005] Patent Document 2 discloses a method for forming a polymer material substrate (excluding fabric substrates) on the surface thereof, the method comprising: ２ (wherein R represents an alkyl group having 6 or more carbon atoms), and then irradiating the surface with ultraviolet light, thereby imparting water repellency to the surface of the polymer material substrate.

[0006] JP 03-128941 A JP 2023-053773 A

[0007] To improve sliding properties, medical rubber articles are coated with silicone oil or laminated with a fluororesin film. However, when silicone oil-coated medical rubber articles come into contact with biopharmaceuticals, protein aggregation due to silicone particles may occur. Therefore, silicone oil-coated medical rubber articles cannot be used for medical supplies that use biopharmaceuticals. In particular, there is a growing demand for silicone oil-free (SOF) plunger stoppers for prefilled syringes.

[0008] In addition, the laminated medical rubber articles that are laminated with fluororesin films such as polytetrafluoroethylene (PTFE) films tend to have poor sealing properties as plunger stoppers for pre-filled syringes because the elastic modulus of PTFE film is 100 times higher than that of rubber.In addition, since PTFE film does not decompose, there are potential risks to the environment and human health, and in the future, PTFE film may become unusable in response to PFAS (perfluoroalkyl or polyfluoroalkyl compounds) regulations.

[0009] As described above, in order to comply with the SOF and PFAS regulations, there is a need for a method for reducing the coefficient of friction and adhesion of 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 has as its object to provide a novel method for producing medical rubber articles that have a reduced surface friction coefficient and tackiness.

[0011] The method for producing a medical rubber article of the present invention is characterized by the step of irradiating a cured product of a medical rubber composition containing (a) a base polymer containing a halogenated butyl rubber and (b) a particulate polyolefin resin with ultraviolet light. The present inventors have discovered that irradiating a cured product of a medical rubber composition containing (a) a base polymer containing a halogenated butyl rubber and (b) a particulate polyolefin resin with ultraviolet light significantly modifies the surface of the cured product to have a low coefficient of friction and low tack (a tack value of almost zero), and have completed the present invention.

[0012] By using the method for manufacturing medical rubber articles of the present invention, medical rubber articles having a reduced surface coefficient of friction and reduced tackiness can be obtained.

[0013] FIG. 1 is an explanatory diagram of one embodiment of a medical rubber article of the present invention (plunger stopper). FIG. 2 is an explanatory diagram of one embodiment of a medical rubber article of the present invention (rubber stopper). FIG. 3 is an explanatory diagram of one embodiment of a medical rubber article of the present invention (rubber stopper for vial bottle). FIG. 4 is an explanatory diagram of one embodiment of a medical rubber article of the present invention (nozzle cap). FIG. 5 is an explanatory diagram of one embodiment of a medical rubber article of the present invention (rubber stopper for vacuum blood collection tube). FIG. 6 is an explanatory diagram of a method for measuring the coefficient of friction of a medical rubber article.

[0014] The method for manufacturing a medical rubber article of the present invention is characterized by including a step of irradiating ultraviolet light to a cured product of a medical rubber composition containing (a) a base polymer containing a halogenated butyl rubber and (b) a particulate polyolefin resin (hereinafter sometimes simply referred to as the "ultraviolet light 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 a halogenated butyl rubber and (b) a particulate polyolefin resin. First, the medical rubber composition will be described.

[0016] <Medical Rubber Composition> [(a) Base Polymer] The (a) base polymer contains halogenated butyl rubber. The halogenated butyl rubber undergoes a crosslinking reaction during the ultraviolet irradiation step, increasing the elastic modulus of the entire (a) base polymer at the rubber surface and making it less susceptible to deformation. As a result, the medical rubber article obtained by the manufacturing method of the present invention has a reduced true contact area at the contact surface with other articles, resulting in a lower coefficient of friction.

[0017] (a) Examples of the halogenated butyl rubber contained in the base polymer include chlorinated butyl rubber, brominated butyl rubber, and brominated copolymers of isobutylene and p-methylstyrene. These halogenated butyl rubbers may be used alone or in combination of two or more. The halogenated butyl rubber is preferably chlorinated butyl rubber or brominated butyl rubber. The chlorinated butyl rubber or brominated butyl rubber is, for example, obtained by adding or substituting chlorine or bromine to the isoprene structure of butyl rubber, specifically to the double bond and / or the carbon atom adjacent to the double bond. Butyl rubber is a copolymer obtained by polymerizing isobutylene and a small amount of isoprene. The halogenated butyl rubber is preferably solid at room 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, and is 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 moieties during the ultraviolet irradiation process. (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 moieties during the ultraviolet irradiation process.

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

[0021] Specific examples of the brominated butyl rubber include Exxon Bromobutyl 2211 (halogen content: 2.0 wt %, Mooney viscosity: 32 ML) manufactured by Exxon Mobil Corporation. １＋８ (125°C), specific gravity: 0.93], Exxon Bromobutyl 2222 [halogen content: 2.0 wt%, Mooney viscosity: 32 ML １＋８ (125°C), specific gravity: 0.93], Exxon Bromobutyl 2235 [halogen content: 2.1 wt%, Mooney viscosity: 39 ML １＋８ (125°C), specific gravity: 0.93], Exxon Bromobutyl 2244 [halogen content: 2.0 wt%, Mooney viscosity: 46 ML １＋８ (125°C), specific gravity: 0.93], Exxon Bromobutyl 2255 [halogen content: 2.1 wt%, Mooney viscosity: 46ML １＋８ (125°C), specific gravity: 0.93], Exxon Bromobutyl 6222 [halogen content: 2.4 wt%, Mooney viscosity: 32 ML １＋８ (125°C), specific gravity: 0.93], Exxon Bromobutyl 7211 [halogen content: 2.0 wt%, Mooney viscosity: 32 ML １＋８ (125°C), specific gravity: 0.93], Exxon Bromobutyl 7244 [halogen content: 2.1 wt%, Mooney viscosity: 46ML １＋８ (125°C, specific gravity: 0.93); LANXESS X_BUTYL BBX2 manufactured by LANXESS Corporation.

[0022] (a) The base polymer may contain a rubber component other than halogenated butyl rubber. Examples of other rubber components include butyl rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, natural rubber, chloroprene rubber, nitrile rubber 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, phosphane rubber, and 1,2-polybutadiene. These may be used alone or in combination of two or more.

[0023] When other rubber components are used, the content of the halogenated butyl rubber in the (a) base polymer is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 98% by mass or more. In a preferred embodiment, the (a) base polymer consists solely of the halogenated butyl rubber.

[0024] [(b) Particulate Polyolefin Resin] (b) The particulate polyolefin resin is resin particles made of a polyolefin resin.

[0025] (b) The particulate polyolefin resin hardly absorbs ultraviolet light (especially ultraviolet light with a wavelength of 160 nm or more), so it does not react during the ultraviolet irradiation step and is exposed to the surface of the cured medical rubber composition. As a result, the medical rubber article obtained by the manufacturing method of the present invention has a further reduced true contact area at the contact surface with other parts, thereby achieving a further reduction in the friction coefficient of the rubber part surface.

[0026] The polyolefin resin is not particularly limited, but examples thereof include 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 an α-olefin (for example, an α-olefin having 3 to 8 carbon atoms); polypropylene resins such as polypropylene (PP), propylene-ethylene copolymer, and copolymers of propylene and an α-olefin (for example, an α-olefin having 4 to 8 carbon atoms); and homopolymers or copolymers of olefins (for example, olefins having 4 to 8 carbon atoms) such as polybutene, polypentene, and polymethylpentene. These may be used alone or in combination of two or more. The polyethylene resin refers to a resin in which the mass proportion of repeating units derived from ethylene in the resin is greater than 50% by mass (preferably 70% by mass or more, more preferably 90% by mass or more), and the polypropylene resin refers to a resin in which the mass proportion of repeating units derived from propylene in the resin is greater than 50% by mass (preferably 70% by mass or more, more preferably 90% by mass or more). Among these, polyethylene resins are preferred in terms of achieving the effects of the present invention more favorably, with low-density polyethylene (LDPE), high-density polyethylene (HDPE), and ultra-high molecular weight polyethylene (UHMWPE) being more preferred, and ultra-high molecular weight polyethylene (UHMWPE) being even more preferred.

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

[0028] The volume average particle diameter of the particulate polyolefin resin (b) is preferably 200 μm or less, more preferably 160 μm or less, and even more preferably 120 μm or less. The volume average particle diameter of the particulate polyolefin resin (b) is preferably 10 μm or more, more preferably 15 μm or more, and even more preferably 20 μm or more. This is because within the above range, the particulate polyolefin resin is easily mixed and dispersed uniformly in the polymer. The volume average particle diameter of the particulate polyolefin resin (b) 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 the particulate polyolefin resin (b). 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, and even more preferably 1,500,000 or more, and is 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) was determined by measuring the intrinsic viscosity [η] in a decalin solvent at 135°C and calculating the viscosity average molecular weight using the formula: Mν = k [η] α (Mν is the viscosity average molecular weight, and k and α are constants.) The intrinsic viscosity is measured by a method in accordance with JIS K7367-3 (1999).

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

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

[0034] Specific examples of the ultra-high molecular weight polyethylene (UHMWPE) include Mipelon (registered trademark) PM-200 (viscosity average molecular weight: 1,800,000, volume average particle size (Coulter-Counter method): 10 μm, density: 938 kg / m) manufactured by Mitsui Chemicals, Inc. 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 ] and others.

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

[0036] [Other Components] The medical rubber composition preferably contains (c) a crosslinking agent. The (c) crosslinking agent is blended 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 capable of crosslinking the halogenated butyl rubber. Examples of the (c) crosslinking agent include sulfur, metal oxides, resin crosslinking agents, organic peroxides, and triazine derivatives, which may be used alone or in combination of two or more.

[0037] Examples of sulfur used as a crosslinking agent include insoluble sulfur, powdered sulfur, finely divided sulfur, precipitated sulfur, colloidal sulfur, and sulfur chloride.

[0038] Examples of metal oxides used as crosslinking agents include magnesium oxide, calcium oxide, zinc oxide, and copper oxide.

[0039] Examples of the resin crosslinking agent include alkylphenol formaldehyde resins such as alkylphenol formaldehyde resin, heat-reactive phenol resin, phenol dialcohol resin, bisphenol resin, and heat-reactive bromomethyl alkylated phenol resin.

[0040] Specific examples of the organic peroxides include dialkyl peroxides, peroxy esters, peroxy ketals, and hydroperoxides. Examples of dialkyl peroxides include di(2-t-butylperoxyisopropyl)benzene, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylcumyl peroxy, di-t-hexyl peroxy, di-t-butyl peroxy, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3. Examples of peroxy esters include t-butyl peroxymaleate, t-butylperoxy-3,3,5-trimethylcyclohexanoate, t-butyl peroxylaurate, t-butylperoxyisopropyl monocarbonate, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butyl peroxyacetate, and t-butyl peroxybenzoate. Examples of peroxyketals 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, and 2,2-di(4,4-di(t-butylperoxy)cyclohexyl)propane. Examples of hydroperoxides include p-menthane hydroperoxide and diisopropylbenzene hydroperoxide. These organic peroxides may be used alone or in combination of two or more.

[0041] The triazine derivative used as the crosslinking agent includes, for example, a compound represented by the general formula (1).

[0042]

[0043] [Wherein R represents -SH, -OR １ , -SR ２ , -NHR ３ or -NR ４R ５ (R １ , R ２ , R ３ , R ４ and R ５ represents an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkylaryl group, or a cycloalkyl group. ４ and R ５ may be the same or different. １ and M ２ is H, Na, Li, K, ½ Mg, ½ Ba, ½ Ca, an aliphatic primary amine, a secondary amine or a tertiary amine, a quaternary ammonium salt or a phosphonium salt. １ and M ２ may be the same or different.

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

[0045] Specific examples of the triazine derivative represented by general formula (1) include 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- Examples thereof include 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, and 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 preferred, and 2-dibutylamino-4,6-dimercapto-s-triazine is particularly preferred due to its availability.

[0047] Examples of triazine derivatives 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, and 1,3,5-triazine-2,4,6-trithiol.

[0048] In the medical rubber composition used in the present invention, one type of triazine derivative may be used alone, or two or more types 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 an optimal crosslinking component for crosslinking. When the medical rubber composition contains a chlorinated butyl rubber as the halogenated butyl rubber, it is preferable to contain a triazine derivative as the (c) crosslinking agent. Furthermore, when the medical rubber composition contains a 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, and even more preferably 0.6 parts by mass or more, and is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, relative to 100 parts by mass of the (a) base polymer component. This is because, when the content of the (c) crosslinking agent is within the above range, a rubber having good rubber properties (hardness, tensile strength, Cset) and good processability (less discoloration) can be obtained.

[0051] When a 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, and even more preferably 0.6 parts by mass or more, and preferably 4 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less, per 100 parts by mass of the (a) base polymer component. This is because, when the content of the (c) crosslinking agent is within the above range, a rubber with good rubber properties (hardness, tensile strength, Cset) and good processability (less discoloration) can be obtained.

[0052] When a brominated butyl rubber is used as the halogenated butyl rubber and 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, and even more preferably 2 parts by mass or more, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of the (a) base polymer component. This is because, when the content of the (c) crosslinking agent is within the above range, a rubber with good rubber properties (hardness, tensile strength, Cset) and good processability (less discoloration) 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 leach into the medicinal solution in a syringe, etc. Examples of the vulcanization accelerator include guanidine-based accelerators (e.g., diphenyl guanidine), 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 (d) an acid acceptor. The acid acceptor (d) functions to absorb chlorine-based gases and bromine-based gases generated during crosslinking of the halogenated butyl rubber and to prevent the occurrence of crosslinking inhibition due to these gases. The acid acceptor (d) also functions as a scorch inhibitor during crosslinking of the halogenated butyl rubber and to prevent the compression set of the medical rubber part from increasing.

[0055] (d) Examples of the acid acceptor include hydrotalcite, metal oxides, and metal hydroxides. Examples of hydrotalcite include Mg ４．５ Al ２ (OH) １３ CO ３・3.5H ２ O, Mg ４．５ Al ２ (OH) １３ CO ３ , Mg ４ Al ２ (OH) １２ CO ３ ・3.5H ２ O, Mg ６ Al ２ (OH) １６ CO ３ ・4H ２ O, Mg ５ Al ２ (OH) １４ CO ３ ・4H ２ O, Mg ３ Al ２ (OH) １０ CO ３ ・1.7H ２ Examples of the metal oxide include magnesium oxide, calcium oxide, and zinc oxide. Examples of the metal hydroxide include calcium hydroxide. These acid acceptors may be used alone or in combination of two or more. The metal oxides used as the crosslinking agents described above can also function as acid acceptors.

[0056] The content of (d) the acid acceptor is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 15 parts by mass or less, and more preferably 10 parts by mass or less, relative to 100 parts by mass of the (a) base polymer component, because the content of the acid acceptor within the above range can suppress rust formation on a mold or the like and reduce the problem of the raw material itself becoming white spots.

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

[0058] Examples of the clay include calcined clay and kaolin clay. Specific examples of the clay include SILLITIN (registered trademark) Z manufactured by HOFFMANN MINERAL, SATINTONE (registered trademark) W manufactured by ENGELHARD, NN kaolin clay manufactured by Tsuchiya Kaolin Kogyo Co., Ltd., and PoleStar 200R manufactured by Imerys Specialties Japan.

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

[0060] The content of the filler in the medical rubber composition is preferably set appropriately depending on the rubber hardness, etc., 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, and even more preferably 20 parts by mass or more, and preferably 200 parts by mass or less, more preferably 150 parts by mass or less, and even more preferably 100 parts by mass or less, per 100 parts by mass of the (a) base polymer component.

[0061] The medical rubber composition may further contain colorants such as titanium oxide and carbon black, lubricants such as stearic acid, processing aids, polyethylene glycol as a crosslinking activator, process oil, etc. 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 needed. Kneading can be carried out using, for example, an open roll or an internal kneader. The kneaded product is preferably formed into a ribbon, sheet, pellet, or the like, and more preferably formed into a sheet.

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

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

[0065] <Ultraviolet Irradiation Step> The method for producing a medical rubber article of the present invention includes a step of irradiating the cured product of the medical rubber composition with ultraviolet light (ultraviolet irradiation step). The cured product of the medical rubber composition irradiated with ultraviolet light may be molded into the shape of the final medical rubber article, or may be a preform prior to being molded into the shape of the final medical rubber article.

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

[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. When the wavelength of the ultraviolet light is 160 nm or more, the particulate polyolefin resin (b) hardly absorbs ultraviolet light of this wavelength, and therefore does not react when irradiated with ultraviolet light, and is scattered on the surface of the cured medical rubber composition. The upper limit of the wavelength of the ultraviolet light is not particularly limited, but is preferably 380 nm or less, more preferably 300 nm or less, and even more preferably 200 nm or less. When the wavelength of the ultraviolet light is 380 nm or less, the energy of the ultraviolet light is high, which increases the crosslinking efficiency of the halogenated butyl rubber and makes it less likely to deform. Furthermore, the high-energy ultraviolet light decomposes and evaporates low-molecular-weight components that contribute to the surface adhesion of the cured medical rubber composition, thereby achieving low adhesion. Furthermore, the evaporation of the low-molecular-weight components exposes the particulate polyolefin resin (b) on the surface of the cured product, roughening the surface of the cured product and further reducing the coefficient of friction. Among these, vacuum ultraviolet light having a wavelength of 200 nm or less is particularly preferred, as it allows the effects of the present invention to be obtained more effectively.

[0068] The light source for emitting 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 high energy and can modify the surface in a relatively short time. The excimer lamp emits ultraviolet rays with different wavelengths depending on the type of discharge gas used. For example, xenon (Xe ２When xenon chloride (XeCl) is used, ultraviolet light having a center wavelength of 172 nm is emitted, when xenon bromide (XeBr) is used, 308 nm is emitted, when xenon iodide (XeI) is used, 283 nm is emitted, when xenon iodide (XeI) is used, 193 nm is emitted, when argon fluoride (ArF), 165 nm is emitted, when argon bromide (ArBr), 222 nm is emitted, and when krypton chloride (KrCl) is used, 207 nm is emitted (also called "excimer UV light"). In the present invention, an excimer lamp that emits vacuum ultraviolet light having a center wavelength of 200 nm or less is preferred, and an excimer lamp using xenon (center wavelength: 172 nm) is particularly preferred.

[0069] In the ultraviolet irradiation step, the cumulative irradiance of the cured product of the medical rubber composition is 1000 mJ / cm ２ It is preferable that the concentration is 3000 mJ / cm or more. ２ More preferably, 5000 mJ / cm or more. ２ It is more preferable that the cumulative illuminance of the cured product of the medical rubber composition is 1000 mJ / cm or more. ２ If the irradiation intensity is above this level, the crosslinking of the halogenated butyl rubber is sufficiently carried out, and the low molecular weight components that contribute to the surface adhesion of the cured product of the medical rubber composition are more easily decomposed. ２ Preferably, it is 45,000 mJ / cm or less. ２ More preferably, it is 40,000 mJ / cm or less. ２ It is more preferable that the cumulative illuminance of the cured product of the medical rubber composition is 50,000 mJ / cm or less. ２ This is because a balance between the life of the irradiation equipment and the efficiency of surface modification can be achieved if the cumulative irradiance on the cured product of the medical rubber composition is the total irradiance (arrival irradiance) of ultraviolet light that reaches the surface of the cured product of the medical rubber composition, and can be calculated by multiplying the intensity (arrival intensity) of ultraviolet light that reaches the surface of the cured product of the medical rubber composition by the irradiation time of ultraviolet light.

[0070] The ultraviolet light reaching intensity and irradiation time may be adjusted appropriately so that the integrated illuminance falls within the range described above. Usually, the ultraviolet light reaching intensity is 10 mW / cm ２ / sec~100mW / cm ２ It is preferable that the irradiation time is 10 to 5000 seconds, because by setting the ultraviolet light reaching intensity and irradiation time within these ranges, it is easy to achieve an integrated illuminance within the above range.

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

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

[0073] The method for producing a medical rubber article of the present invention may include the steps of processing the cured product of the medical rubber composition into a predetermined shape, washing, sterilizing, and drying. For example, the medical rubber article is produced by cutting and removing unnecessary parts from the cured product of the medical rubber composition after ultraviolet irradiation to form the predetermined shape, and then washing, sterilizing, drying, and packaging the product. Note that cutting and removing unnecessary parts to form the predetermined shape may be performed before irradiating the cured product of the medical rubber composition with ultraviolet light.

[0074] The medical rubber article obtained by the manufacturing method of the present invention can achieve a low coefficient of friction and low tack without using silicone oil or a resin film such as a fluorine film, etc. Therefore, the medical rubber article of the present invention can be suitably used as a medical rubber article that is required to have a low coefficient of friction and low tack while complying with SOF and PFAS regulations.

[0075] In order to comply with the SOF standard, it is preferable that the medical rubber article obtained by the manufacturing method of the present invention is not coated with silicone oil. Examples of the silicone oil include dimethylpolysiloxane, methylphenylpolysiloxane, and modified products thereof. Furthermore, in order to comply with the PFAS standard, it is preferable that the medical rubber article of the present invention is not laminated with a fluorine-containing resin film. Examples of the fluorine-containing resin film include films made of polytetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene copolymer (ETFE), and modified products thereof.

[0076] Examples of medical rubber articles obtainable by the production method of the present invention include rubber stoppers and sealing members for containers for various drugs such as liquid drugs, powder preparations, and freeze-dried preparations, rubber stoppers for vacuum blood collection tubes, plunger stoppers (gaskets) for pre-filled syringes, and sliding or sealing parts such as nozzle caps. Among these, medical rubber parts (e.g., rubber stoppers and plunger stoppers) that require a low coefficient of friction and low adhesion are preferred, and plunger stoppers that require excellent sliding properties are particularly preferred.

[0077] Of these, rubber stoppers and sealing members, including those for vials and infusion preparation containers, preferably have a rubber hardness of 35 or more and 60 or less in terms of durometer type A hardness (Shore A hardness) measured in accordance with the measurement method described in Japanese Industrial Standards JIS K6253-3:2012 "Vulcanized rubber and thermoplastic rubber -- Determination of hardness -- Part 3: Durometer hardness."

[0078] Furthermore, the sliding or sealing parts of gaskets and nozzle caps for prefilled syringes preferably have a Shore A hardness of 40 or more and 70 or less.

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

[0080] Figure 1 is a diagram showing an exploded view of a medical syringe that uses the medical rubber article of the present invention, a syringe known as a prefillable syringe. In Figure 1, half of a syringe 11 and a plunger stopper 13 are shown 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 that is 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 formed, for example, from a resin plate piece having a cross-shaped cross section, and is provided at its tip with a head portion 18 to which the plunger stopper 13 is attached. The head portion 18 is made of resin and formed integrally with the plunger 12, and is machined into a male thread shape. The plunger stopper 13 is a roughly cylindrical short-axis member, and its tip surface has, for example, an obtuse angled chevron shape with the central axis protruding. A female thread-shaped mating recess 15 is formed axially from the rear end surface. The head portion 18 of the plunger 12 is screwed into the mating recess 15 of the plunger stopper 13, thereby attaching the plunger stopper 13 to the tip of the plunger 12.

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

[0083] The medical rubber stopper 20 comprises a top plate 21 and a stopper leg 22. The top plate 21 has a puncture portion 23 that can be punctured with the injection needle of a syringe and a flange portion 21b that contacts the upper edge surface 24a of the container opening of a medical container 24. The stopper leg 22 protrudes from the underside of the top plate 21 and is fitted into the medical container opening. The stopper leg 22 has a generally cylindrical shape and is provided with a notch 27. A nylon film layer 26 is provided on the top surface of the top plate 21 of the medical rubber stopper 20. Providing the nylon film layer 26 on the top surface of the medical rubber stopper 20 ensures mechanical transportability during pharmaceutical manufacturing. Furthermore, providing the nylon film layer 26 on the top surface of the medical rubber stopper 20 increases the surface smoothness of the top surface, preventing the generation of needle fragments when the injection needle is inserted.

[0084] In the embodiment shown in Figure 3, a vial for storing a freeze-dried preparation is used as container 24. When the liquid pharmaceutical contained in container 24 is an injectable liquid, the needle of a syringe is pierced through puncture portion 23 of top plate 21, and the injectable liquid is drawn into the syringe without opening medical rubber stopper 20. In this way, medical rubber stopper 20 is not opened in order to prevent foreign matter from being mixed into the injectable liquid in container 24.

[0085] A metal or resin cap 25 is provided on the top plate 21, which can cover the opening 24b of the container 24 and the medical rubber stopper 20. The reason for sealing the medical rubber stopper 20 with the cap 25, including the opening 24b, is to prevent mold from adhering to the puncture site 23 where the syringe needle is inserted and then being transferred from the needle to the injection liquid. Types of cap 25 that can be used include flip-off caps, pull-top caps, and clean caps. When large amounts of injection liquid are used, such as in hospitals, it is preferable to use a clean cap, which 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 for a medical syringe and the nozzle of a syringe barrel to be fitted with the nozzle cap. FIG. 4( b) is a cross-sectional view showing the nozzle cap fitted over the nozzle. In this example, nozzle cap 41 is for a needle-equipped syringe 45, in which a needle 44 has been embedded 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 having an inner diameter D1 slightly smaller than the outer diameter D2 of the nozzle 43, and a needle piercing portion 47 connected to one end of the cylindrical portion 46 (the upper end in the figure). The needle piercing portion 47 is formed in a columnar shape with an outer surface continuous with the cylindrical portion 46. The other end of the cylindrical portion 46 (the lower end in the figure) is provided with an opening 48 for inserting a nozzle 43 into the cylindrical portion 46 and fitting the nozzle cap 41 over the nozzle 43.

[0087] 5 is an explanatory diagram showing an example of a vacuum blood collection tube. Vacuum blood collection tube 50 consists of a bottomed tube 51 and a rubber stopper 53 that seals the opening of bottomed tube 51. Such rubber stopper 53 is made of the surface-modified cured product of the present invention. It is designed so that blood can be collected automatically by reducing the pressure inside the blood collection tube.

[0088] The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the following examples, and all modifications and embodiments that do not deviate from the spirit of the present invention are included within the scope of the present invention.

[0089] [Preparation of Medical Rubber Articles] The materials shown in Table 1 were kneaded using an open roll at 60°C for 20 minutes to prepare a medical rubber composition. The resulting medical rubber composition was crosslinked under molding conditions of 170°C for 15 minutes, and then punched out into circular slabs with a diameter of 28 mm and a thickness of 2 mm to prepare a test specimen for ultraviolet irradiation (cured product of medical rubber composition). The test specimen for ultraviolet irradiation was irradiated with vacuum ultraviolet light (wavelength: 172 nm) to achieve the cumulative illuminance shown in Table 1. Ultraviolet irradiation conditions: Irradiation device: Electrodeless excimer 172 nm irradiation device (manufactured by MD.com Co., Ltd.); Distance between the surface of the cured product and the lamp: 7 mm; UV light intensity: 57.9 mW / cm ２ / sec

[0090]

[0091] Details of the compounding materials used are as follows: Chlorinated butyl rubber: Exxon (registered trademark) Chlorobutyl 1066 (chlorine content: 1.25 wt%) manufactured by ExxonMobil Corporation General-purpose butyl rubber: Exxon (registered trademark) Butyl 268 (unsaturation: 2.30 mol%) manufactured by ExxonMobil Corporation Ultra-high molecular weight polyethylene: Mipelon (registered trademark) XM-220 (volume average particle size: 30 μm, viscosity average molecular weight: 2 million) manufactured by Mitsui Chemicals, Inc. Triazine derivative: Jisnet DB manufactured by Sankyo Kasei Co., Ltd. Sulfur: Insoluble sulfur (Seimi OT) manufactured by Nippon Kanritsu Kogyo Co., Ltd. Zinc oxide: Activated zinc oxide AZO manufactured by Seido Chemical Industry Co., Ltd. Magnesium oxide: Magsarat 150s manufactured by Kyowa Chemical Industry Co., Ltd. Dithiocarbamate: Noccela (registered trademark) ZTC manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0092] [Evaluation Method] (1) Friction Coefficient <Measurement of Static and Dynamic Friction Coefficients> Figure 6 is an explanatory diagram showing the method for measuring the friction coefficient of the medical rubber article (a circular slab with a thickness of 2 mm and a diameter of 28 mm after UV irradiation) prepared as described above using a static and dynamic friction coefficient measuring instrument TL201 (manufactured by TAILAB). A measurement sample 63 was fixed to a lower stage 64, and a 10 g weight 61 was placed on a dedicated probe equipped with a 10 mm diameter SUS ball 62, bringing the surface of the measurement sample 63 into contact with the SUS ball 62. The stage 64 was then moved in the direction of the arrow over a distance of 20 mm at a speed of 10 mm / s. The friction coefficient μ was calculated by dividing the generated friction force F by the load (normal force) N (μ = F / N). The coefficient was calculated by dividing the coefficient by the average normal force N1 over a travel distance of 20 mm, and the coefficient was calculated by dividing the coefficient by the maximum average normal force N2 over a travel distance of 20 mm, to obtain the coefficient of static friction. <Evaluation of static friction coefficient> The static friction coefficient was evaluated according to the following evaluation criteria. ○: The static friction coefficient was less than 1.50. ×: The static friction coefficient was 1.50 or more. <Evaluation of dynamic friction coefficient> The dynamic friction coefficient was evaluated according to the following evaluation criteria. ○: The dynamic friction coefficient was less than 1.30. ×: The dynamic friction coefficient was 1.30 or more.

[0093] (2) Adhesion Test <Measurement of Tack Value> For the medical rubber article (circular slab with a thickness of 2 mm and a diameter of 28 mm after UV irradiation) prepared as described above, a testing machine EZ-SX (manufactured by Shimadzu Corporation) was used to fix the medical rubber article to a dedicated jig on the lower side, and an upper metal Φ10 mm SUS probe was pressed against the surface of the medical rubber article. After reaching a set pressure (10 N), the pressure was held for 10 seconds and then raised at a speed of 10 mm / s. The peak value of the adhesion force generated between the probe and the cured product of the rubber composition was defined as the tack value. Five measurements were taken, and the average value of three measurements, excluding the max and min values, was taken as the tack value. <Evaluation of Adhesion> Adhesion was evaluated according to the following evaluation criteria. ◯: Tack value is 0.5 N or less. ×: Tack value is greater than 0.5 N.

[0094] (3) Overall Evaluation ◯: The evaluation results of the friction coefficient and the adhesiveness are both ◯. ×: Both the evaluation results of the friction coefficient and the adhesiveness are ×.

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

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

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

[0098] 10: syringe, 11: syringe, 12: plunger, 13: gasket, 18: head portion, 20: medical rubber stopper, 21: top plate, 22: stopper leg, 23: puncture portion, 24: medical container, 26: nylon film layer, 25: cap, 41: nozzle cap, 42: syringe barrel, 43: nozzle, 44: needle, 45: syringe with needle

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

[0100] A preferred embodiment (2) of the present invention is the method for producing medical rubber articles 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 a brominated copolymer of isobutylene and p-methylstyrene.

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

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

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

[0104] A preferred aspect (6) of the present invention is the method for producing a medical rubber article according to any one of aspects (1) to (5), wherein (b) 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 the method for producing a medical rubber article according to any one of embodiments (1) to (6), wherein the ultraviolet light has a wavelength of 160 nm to 380 nm.

[0106] In a preferred embodiment (8) of the present invention, the cumulative illuminance of the cured product of the medical rubber composition is 1000 mJ / cm ２The above is a method for producing a medical rubber article according to any one of aspects (1) to (7).

[0107] A preferred aspect (9) of the present invention is the method for producing a medical rubber article according to any one of aspects (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 ultraviolet rays to 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 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.

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

6. The method for manufacturing a medical rubber article according to claim 1, 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.

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 method for manufacturing a medical rubber article according to any one of claims 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.

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