Method for producing medical rubber article

Abstract

[Problem] To provide a method for producing a medical rubber article which has a surface having a reduced coefficient of friction and reduced tackiness. [Solution] This method for producing a medical rubber article is characterized by including (a) a step in which as a base rubber, a cured object formed from a medical rubber composition including a halogenated butyl rubber is irradiated with ultraviolet light.

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 articles 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 article is sticky (high tack value). This results in poor sliding properties, and furthermore, the rubber articles tend to stick to each other after long-term storage. To improve sliding properties and reduce frictional resistance, the surface of the vulcanized rubber article 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] Furthermore, laminated medical rubber articles laminated with a fluororesin film such as a polytetrafluoroethylene (PTFE) film tend to have poor sealing properties when used as a plunger stopper for a prefilled syringe, because the elastic modulus of the PTFE film is 100 times higher than that of rubber.

[0009] To comply with the SOF regulations, there is a need for a method to reduce the coefficient of friction and tack of surfaces of medical rubber articles without using silicone oil.

[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 comprising the step of irradiating with ultraviolet light a cured product of a medical rubber composition containing a halogenated butyl rubber as a base polymer (a). The present inventors have found that irradiating with ultraviolet light a cured product of a medical rubber composition containing a halogenated butyl rubber as a base polymer (a) 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 (plunger stopper) of the medical rubber article of the present invention. FIG. 2 is an explanatory diagram of one embodiment (plunger stopper) of the medical rubber article of the present invention. FIG. 3 is an explanatory diagram of one embodiment (rubber stopper) of the medical rubber article of the present invention. FIG. 4 is an explanatory diagram of one embodiment (rubber stopper) of the medical rubber article of the present invention. FIG. 5 is an explanatory diagram of one embodiment (rubber stopper) of the medical rubber article of the present invention. FIG. 6 is an explanatory diagram of one embodiment (rubber stopper) of the medical rubber article of the present invention. FIG. 7 is an explanatory diagram of one embodiment (rubber stopper) of the medical rubber article of the present invention.

[0014] The method for producing a medical rubber article of the present invention is characterized by including (a) a step of irradiating ultraviolet light to a cured product of a medical rubber composition containing a halogenated butyl rubber as a base polymer (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 halogenated butyl rubber as (a) the base polymer. 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] The medical rubber composition preferably contains (b) a crosslinking agent. The (b) crosslinking agent is blended to crosslink the halogenated butyl rubber component contained in the (a) base polymer. The (b) crosslinking agent is not particularly limited as long as it is capable of crosslinking the halogenated butyl rubber. Examples of the (b) 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.

[0025] Examples of sulfur used as a crosslinking agent include insoluble sulfur, powdered sulfur, finely divided sulfur, precipitated sulfur, colloidal sulfur, and sulfur chloride.

[0026] Examples of metal oxides used as crosslinking agents include magnesium oxide, calcium oxide, zinc oxide, and copper oxide.

[0027] 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.

[0028] 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.

[0029] The triazine derivative used as the crosslinking agent includes, for example, a compound represented by the general formula (1).

[0030]

[0031] [Wherein R represents -SH, -OR １ , -SR ２ , -NHR ３ or -NR ４ R 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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 crosslinking agent (b). 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 crosslinking agent (b).

[0038] The content of the (b) 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 (b) 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.

[0039] When a chlorinated butyl rubber is used as the halogenated butyl rubber and a triazine derivative is used as the (b) crosslinking agent, the content of the (b) 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 (b) 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.

[0040] When a brominated butyl rubber is used as the halogenated butyl rubber and a metal oxide is used as the (b) crosslinking agent, the content of the (b) 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 (b) 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.

[0041] 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).

[0042] The medical rubber composition may further contain an acid acceptor. The acid acceptor 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 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.

[0043] Examples of the acid acceptor include hydrotalcite, metal oxides, and metal hydroxides.

[0044] Examples of hydrotalcite include Mg ４．５ Al ２ (OH) １３ CO３ ・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.

[0045] The content of 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 problems such as the raw material itself becoming white spots.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] The medical rubber composition is obtained by kneading (a) a base polymer, (b) a crosslinking agent, 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.

[0052] The method for producing a medical rubber article of the present invention may include a step of curing the medical rubber composition. The cured product of the medical rubber composition used in 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 a ribbon-, sheet-, or pellet-shaped kneaded product. 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.

[0053] The cured product of the medical rubber composition to which the present invention is applied may have at least a portion of its surface coated with an inactive resin layer. For example, by press-molding a sheet made of the medical rubber composition with an inactive resin film superimposed thereon, at least a portion of the surface of the cured product of the medical rubber composition is coated with the inactive resin layer.

[0054] The inactive resin layer may be applied to at least a portion of the surface of the medical rubber article, and is preferably applied appropriately depending on the shape of the medical rubber article. In particular, it is preferable to provide an inactive resin layer on the surface of the medical rubber article that comes into contact with chemicals. In this embodiment, the inactive resin layer exhibits good chemical resistance, and the sliding properties of the surface not provided with the inactive resin layer can be improved by ultraviolet irradiation.

[0055] The resin constituting the inactive resin layer is not particularly limited, but examples thereof include at least one fluororesin selected from the group consisting of tetrafluoroethylene-ethylene copolymer (ETFE), polytetrafluoroethylene (PTFE), and polychlorotetrafluoroethylene (PCTFE), or a non-fluororesin, in terms of obtaining good chemical resistance.

[0056] Tetrafluoroethylene-ethylene copolymer (ETFE) is a copolymer of ethylene and tetrafluoroethylene in a molar ratio of 30 / 70 to 70 / 30, and there is also modified ETFE in which other components are further copolymerized for the purpose of modification. Examples of other components include fluorine-containing olefins and hydrocarbon olefins. Specifically, α-olefins such as propylene and butene, fluorine-containing olefins such as hexafluoropropylene, vinylidene fluoride, perfluorobutylethylene, and trifluorochloroethylene, vinyl ethers such as ethylene vinyl ether, perfluoromethyl vinyl ether, and perfluoropropyl vinyl ether, and fluorine-containing acrylates are copolymerized at about 2 to 10 mol% to modify ETFE.

[0057] As the modified ETFE, ETFE having a functional group that imparts adhesiveness can be suitably used, and examples of the functional group include a carboxyl group, a carboxyl anhydride group, an epoxy group, a hydroxyl group, an isocyanate group, an ester group, an amide group, an aldehyde group, an amino group, a cyano group, a carbon-carbon double bond, a sulfonic acid group, an ether group, etc. Furthermore, an example of a commercially available modified ETFE is Fluon AH-2000 manufactured by Asahi Glass Co., Ltd.

[0058] Examples of non-fluorine-containing resins include olefin-based resins. Examples of the olefin-based resins include polyethylene-based resins such as polyethylene, ethylene-propylene copolymer, ethylene-propylene-non-conjugated diene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-ethyl acrylate copolymer, and chlorinated polyethylene; polypropylene-based resins such as polypropylene, propylene-ethylene random copolymer, propylene-ethylene block copolymer, and chlorinated polypropylene; polybutene, polyisobutylene, polymethylpentene, and cyclic olefin copolymers; and polyethylene (particularly ultra-high molecular weight polyethylene (UHMWPE)). The olefin-based resin may contain fluorine.

[0059] The thickness of the inactive resin film used may be adjusted appropriately according to the shape and size of the medical rubber article, but is preferably 10 μm or more, more preferably 20 μm or more, even more preferably 30 μm or more, and is preferably 150 μm or less, more preferably 130 μm or less, and even more preferably 110 μm or less, because if the thickness of the inactive resin film is within the above range, the film will not break during product molding, and wrinkles or floating defects will not occur on the film surface of the product after molding, and both moldability and product properties can be achieved.

[0060] The arithmetic mean roughness Ra of the inactive resin film ranges from 0.01 to 0.03 μm for cast films and extruded films to 0.10 μm for skived films, but by setting the surface roughness of the mold to 0.03 μm or less, medical rubber articles with excellent liquid adhesion and airtightness can be obtained. There is no particular lower limit for the Ra of the inactive film itself.

[0061] The inactive resin film is preferably subjected to a treatment to enhance its adhesiveness to rubber, etc. Examples of treatments to enhance adhesiveness include chemical treatments, treatments for roughening the surface of the film, and combinations of these, and specific examples include sodium treatment, glow discharge treatment, plasma treatment (discharge treatment) under atmospheric pressure or in a vacuum, excimer laser treatment (discharge treatment), and ion beam treatment.

[0062] <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.

[0063] 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.

[0064] 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. This is because ultraviolet light with a wavelength of 160 nm or more can modify the surface. Furthermore, the upper limit of the ultraviolet light wavelength 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 reduces deformation. Furthermore, high-energy ultraviolet light decomposes and evaporates low-molecular-weight components that contribute to the surface adhesion of the cured product of the medical rubber composition, thereby achieving low adhesion. Furthermore, the evaporation of the low-molecular-weight components roughens the surface of the cured product, further reducing the coefficient of friction. Among these, vacuum ultraviolet light with a wavelength of 200 nm or less is particularly preferred in terms of achieving the effects of the present invention more effectively.

[0065] 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 ２ When 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.

[0066] In the ultraviolet irradiation step, the cumulative irradiance of ultraviolet light on 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 ultraviolet ray irradiance is above 50000 mJ / cm, the halogenated butyl rubber is sufficiently crosslinked 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. ２This is because, if the irradiation time is less than this, a balance can be achieved between the life of the irradiation equipment and the efficiency of surface modification. Note that the integrated illuminance of ultraviolet light on the cured product of the medical rubber composition is the total illuminance (arrival illuminance) 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] In the manufacturing method of the present invention, when at least a portion of the surface of the cured product of the medical rubber composition is coated with an inactive resin layer, it is preferable to irradiate the exposed rubber surface that is not coated with the inactive resin layer with ultraviolet light. Only a portion of the exposed rubber surface may be irradiated with ultraviolet light, or the entire exposed rubber surface may be irradiated with ultraviolet light.

[0071] 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.

[0072] 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, and therefore can be suitably used as a medical rubber article that meets the SOF regulations and requires a low coefficient of friction and low tack.

[0073] In view of SOF compatibility, it is preferable that the medical rubber article obtained by the manufacturing method of the present invention is not coated with silicone oil, such as dimethylpolysiloxane, methylphenylpolysiloxane, and modified products thereof.

[0074] 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 articles (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.

[0075] 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."

[0076] 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.

[0077] The rubber hardness of medical rubber articles can be adjusted by changing the blending ratio of each raw material.

[0078] Specific examples of medical rubber articles to which the present invention is applied are described below. <Plunger Stopper> Figure 1 is a diagram showing an exploded view of a medical syringe, a so-called prefillable syringe 30, in which the medical rubber article of the present invention is used. In Figure 1, half of the syringe barrel 31 and plunger stopper 33 are shown in cross section. The prefillable syringe 30 includes a cylindrical syringe barrel 31, a plunger 32 that is combined with the syringe barrel 31 and can reciprocate within the syringe barrel 31, and a plunger stopper 33 that is attached to the tip of the plunger 32.

[0079] The plunger 32 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 38 to which the plunger stopper 33 is attached. The head portion 38 is made of resin and formed integrally with the plunger 32, and is machined into a male thread shape. The plunger stopper 33 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 35 is formed axially from the rear end surface. The head portion 38 of the plunger 32 is screwed into the mating recess 35 of the plunger stopper 33, thereby attaching the plunger stopper 33 to the tip of the plunger 32.

[0080] 2 is a half-sectional front view of an example of a plunger stopper. Plunger stopper 40 includes a main body 41 made of a cured medical rubber composition and an inactive resin layer 42 that covers a portion of the surface of the main body. Plunger stopper 40 has a liquid-contacting surface 47 that faces the medicinal solution and a sliding surface 46 that contacts the syringe barrel.

[0081] 2, when plunger stopper 40 is inserted into the syringe barrel, only mountain-shaped liquid contact surface 47 that comes into contact with the drug solution is coated with inactive resin layer 42. As inactive resin layer 42, for example, a polytetrafluoroethylene film is preferable.

[0082] The sliding surface (outer peripheral surface) 46 where the plunger stopper 40 comes into contact with the syringe barrel is not provided with the inactive resin layer 42 and is irradiated with ultraviolet light. The sliding surface (outer peripheral surface) 46 has high slidability.

[0083] The plunger stopper 40 has a short cylindrical shape and includes a plurality of annular ribs 43, 44, and 45 on an outer peripheral surface 46 of the cylindrical shape. The annular ribs are in sliding contact with the inner peripheral surface of the syringe barrel. The plurality of annular ribs are arranged in the axial direction from a leading end surface (liquid contact surface) 47 of the plunger stopper to a rear end surface 48. The number of annular ribs is not particularly limited as long as it is one or more, but is preferably two or more, more preferably three or more, and preferably six or less, more preferably five or less, and even more preferably four or less.

[0084] The plunger stopper 40 in Fig. 2 has, from the tip side, a first annular rib 43, a second annular rib 44, and a third annular rib 45. The first annular rib 43 at the tip preferably has a radial compression rate of 1% or more, more preferably 2% or more, even more preferably 3% or more, preferably 10% or less, more preferably 9% or less, and even more preferably 8% or less. The compression rate is calculated from the outer diameter D1 of the annular rib in an uncompressed state and the inner diameter R of the syringe barrel using the following formula: Compression rate (%) = 100 x (D1 - R) / D1

[0085] The linear length H1 (the axial length) of the sliding contact portion of the annular rib 43 at the tip is preferably 1% or more, more preferably 3% or more, and even more preferably 6% or more, of the linear length Ho of the outer peripheral surface of the cylindrical shape (the axial length of the outer peripheral surface), and is preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less.

[0086] The linear length H2 (axial length) of the sliding contact portion of the second annular rib 44 and the linear length H3 (axial length) of the sliding contact portion of the third annular rib 45 are each preferably 1% or more, more preferably 2% or more, and even more preferably 3% or more, of the linear length Ho (axial length of the outer peripheral surface) of the cylindrical outer peripheral surface, and are preferably 15% or less, more preferably 14% or less, and even more preferably 13% or less.

[0087] The plunger stopper may be called a stopper or a gasket.

[0088] <Rubber stopper> Figure 3 is an explanatory diagram illustrating an example of a medical stopper to which the present invention is applied. More specifically, it is a rubber stopper for a vial. Figure 3(a) is a plan view, and Figure 3(b) is a cross-sectional view taken along line A-A in Figure 3(a).

[0089] The medical plug 50 has a top plate 53 and cylindrical legs 55 extending downward from the underside of the top plate 53. The top plate 53 and legs 55 are made of a cured rubber composition. When a medical container is stoppered with the medical plug of the present invention, the legs 55 fit into the opening of the medical container. In Figure 3(b), the opposing inner surfaces of the cylindrical legs 55 are tapered so that the distance between the inner surfaces of the legs gradually decreases from the bottom to the top (towards the top).

[0090] The top plate 53 has a circular shape in a plan view and includes a puncture portion 53a that can be punctured with the needle of a syringe, and a flange portion 53b that contacts the upper edge surface of the opening of the medical container when the medical container is capped.

[0091] A protrusion 57 is provided on the top surface of the flange portion 53b to prevent it from coming into close contact with other rubber stoppers.

[0092] Puncture portion 53a is a region in top plate 53 into which an injection needle is inserted to aspirate the medicinal liquid inside the container. Puncture portion 53a is circular in plan view and is located in the center of top plate 53. Puncture portion 53a is formed in a concave shape on the top surface.

[0093] 3, the entire lower surface of the top plate 53 and the entire surface of the legs 55 are covered with an inactive resin layer 59. The inactive resin layer 59 may cover at least a portion of the lower surface of the top plate 53 and the entire surface of the legs 55. A polytetrafluoroethylene film is preferred as the inactive resin layer 59.

[0094] The upper surface of the top plate 53 is not provided with an inactive resin layer and is irradiated with ultraviolet light. The upper surface of the top plate 53 has a reduced coefficient of friction and adhesiveness, which alleviates the problem of rubber stoppers sticking together.

[0095] Figure 4 is an explanatory diagram showing another embodiment of a medical rubber stopper 50 to which the present invention is applied. Figure 4(a) is a plan view, and Figure 4(b) is a cross-sectional view taken along line B-B in Figure 4(a). Descriptions of parts of the medical rubber stopper 50 in Figure 4 that are common in configuration to Figure 3 will be omitted.

[0096] The medical rubber stopper 50 of this embodiment has bifurcated legs 55 extending from the underside of the top plate 53. In Fig. 4(b), the opposing inner surfaces of the bifurcated legs 55 are tapered so that the distance between the inner surfaces of the legs gradually decreases from bottom to top (towards the top surface). In the embodiment of Fig. 4, the top plate 53 and the legs 55 are made of a cured rubber composition, and the entire underside of the top plate 53 and the entire surface of the legs 55 are coated with an inactive resin layer 59. Note that the inactive resin layer 59 may cover at least a portion of the underside of the top plate 53 and the surface of the legs 55.

[0097] The upper surface of the top plate 53 is not provided with an inactive resin layer and is irradiated with ultraviolet light. The upper surface of the top plate 53 has a reduced coefficient of friction and adhesiveness, which alleviates the problem of rubber stoppers sticking together.

[0098] A nylon film layer may be provided on the top surface of the top plate 53 of the medical rubber stopper 50 in Figures 3 and 4. By providing a nylon film layer on the top surface of the medical rubber stopper 50, mechanical transportability during pharmaceutical manufacturing can be ensured. In addition, by providing a nylon film layer on the top surface of the medical rubber stopper 50, the surface smoothness of the top surface can be increased, preventing the generation of needle fragments when punctured with an injection needle.

[0099] <Rubber stopper of vacuum blood collection tube> Figure 5 is an explanatory diagram showing an example of a vacuum blood collection tube. A vacuum blood collection tube 90 comprises a bottomed tube 91 and a rubber stopper 93 that seals the opening of the bottomed tube 91. It is designed so that blood can be collected automatically by reducing the pressure inside the blood collection tube.

[0100] FIG. 6 is an explanatory diagram illustrating an example of a medical stopper to which the present invention is applied. It is an explanatory diagram illustrating an example of a rubber stopper for a vacuum blood collection tube. FIG. 6( a) is a perspective view, and FIG. 6( b) is a cross-sectional view. The rubber stopper for a vacuum blood collection tube has a top plate 94 and a cylindrical leg portion 95 extending downward from the underside of the top plate 94. The top plate 94 and the leg portion 95 are made of an elastic material. The leg portion 95 fits into the opening of the vacuum blood collection tube when the vacuum blood collection tube is stoppered with the rubber stopper. A puncture portion 96, which is an area for inserting an injection needle, is provided in the center of the top plate 94. The puncture portion 96 is formed in a concave shape from the top surface. The underside of the top plate 94 and the entire surface of the leg portion 95 are coated with an inactive resin layer 97. Note that the inactive resin layer 97 may cover at least a portion of the underside of the top plate 94 and the surface of the leg portion 95.

[0101] The upper surface of the top plate 94 is not provided with an inactive resin layer and is irradiated with ultraviolet light. The upper surface of the top plate 94 has a reduced coefficient of friction and adhesiveness, which alleviates the problem of rubber stoppers sticking together.

[0102] <Nozzle Cap> Figure 7(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. Figure 7(b) is a cross-sectional view showing the nozzle cap fitted over the nozzle. The nozzle cap 81 is integrally formed from a medical rubber composition. The nozzle cap 81 includes a cylindrical portion 86 having an inner diameter D8 slightly smaller than the outer diameter D9 of the nozzle 83, and a needle portion 87 connected to one end (the upper end in the figure) of the cylindrical portion 86. The needle portion 87 is formed in a columnar shape with an outer surface continuous with the cylindrical portion 86. The other end (the lower end in the figure) of the cylindrical portion 86 is provided with an opening 88 for inserting the nozzle 83 into the cylindrical portion 86 and fitting the nozzle cap 81 over the nozzle 83. The inner surface of the nozzle cap 81 and the surface of the lower end of the cylindrical portion 86 are coated with an inactive resin layer 84.

[0103] The outer surface of the nozzle cap 81 is not provided with an inactive resin layer and is irradiated with ultraviolet light. The outer surface of the nozzle cap 81 has a reduced coefficient of friction and adhesiveness, which alleviates the problem of nozzle caps sticking together.

[0104] 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.

[0105] [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

[0106]

[0107] 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 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.

[0108] [Evaluation Method] (1) Friction Coefficient <Measurement of Static and Dynamic Friction Coefficients> Figure 8 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 friction force F generated at this time by the load (normal force) N. (μ = F / N) The coefficient of kinetic friction was calculated by dividing the coefficient by the average normal force N1 over a travel distance of 20 mm, and the coefficient of static friction was calculated by dividing the coefficient by the maximum average normal force N2 over a travel distance of 20 mm. <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 and less than 3.3. ×: The static friction coefficient was 3.3 or more. A static friction coefficient of less than 3.3 was considered acceptable. <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 and less than 2.00. ×: The dynamic friction coefficient was 2.00 or more. A dynamic friction coefficient of less than 2.00 was considered acceptable.

[0109] (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 rate of 10 mm / sec. 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 was 0.55 N or less. ×: Tack value was greater than 0.55 N.

[0110] (3) Overall Evaluation ◯: The evaluation results of the friction coefficient and the adhesion are ◯ or Δ. ×: The evaluation results of both the friction coefficient and the adhesion are ×.

[0111] The measurement and evaluation results of the friction coefficient and adhesion are shown in Table 1. From Table 1, it can be seen that the medical rubber articles obtained by the manufacturing method of the present invention have reduced surface friction coefficients and adhesion.

[0112] 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).

[0113] A preferred embodiment (1) of the present invention is a method for producing a medical rubber article, which comprises the step of irradiating with ultraviolet light a cured product of a medical rubber composition containing a halogenated butyl rubber as a base polymer (a).

[0114] A preferred embodiment (2) of the present invention is the method for producing medical rubber articles according to embodiment (1), wherein the ultraviolet light has a wavelength of 160 nm to 380 nm.

[0115] In a preferred embodiment (3) of the present invention, the cumulative irradiance of ultraviolet light on the cured product is 1000 mJ / cm ２ ~50000mJ / cm ２The method for producing a medical rubber article according to aspect (1) or (2) is as follows:

[0116] A preferred embodiment (4) of the present invention is the method for producing a medical rubber article according to any one of embodiments (1) to (3), 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.

[0117] A preferred embodiment (5) of the present invention is the method for producing a medical rubber article according to any one of the embodiments (1) to (4), in which (a) the base polymer consists solely of halogenated butyl rubber.

[0118] A preferred embodiment (6) of the present invention is the method for producing a medical rubber article according to any one of embodiments (1) to (5), in which at least a portion of the surface of the cured product is coated with an inactive resin layer, and the exposed rubber surface that is not coated with the inactive resin layer is irradiated with ultraviolet light.

[0119] A preferred embodiment (7) of the present invention is the method for producing medical rubber articles according to embodiment (6), in which the inactive resin layer is a layer made of a fluororesin.

[0120] A preferred embodiment (8) of the present invention is the method for producing medical rubber articles according to embodiment (6), wherein the inactive resin layer is a layer made of a non-fluorine-containing resin.

[0121] 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.

[0122] A preferred aspect (10) of the present invention is the method for producing a medical rubber article according to aspect (6), wherein the medical rubber article is a syringe plunger stopper having a liquid-contacting surface portion facing a medicinal solution and a sliding surface portion in contact with a barrel, the liquid-contacting surface portion being coated with an inactive resin layer, and the sliding surface portion not being coated with an inactive resin layer, with the cured product of the medical rubber composition being exposed.

[0123] A preferred embodiment (11) of the present invention is the method for producing a medical rubber article according to embodiment (10), in which the inactive resin layer is a layer made of a fluororesin.

[0124] A preferred embodiment (12) of the present invention is the method for producing a medical rubber article according to embodiment (10), in which the inactive resin layer is a layer made of a non-fluorine-containing resin.

Claims

1. A method for manufacturing a medical rubber article, comprising the step of irradiating a cured product of a medical rubber composition containing a halogenated butyl rubber as a base polymer with ultraviolet light.

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

3. The integrated illuminance of ultraviolet rays on the cured product is 1000 mJ / cm ２ to 50000 mJ / cm ２ The method for producing a medical rubber article according to claim 1, wherein the integrated illuminance of ultraviolet rays on the cured product is 1000 mJ / cm to 50000 mJ / cm 4. 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.

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

6. The method for manufacturing a medical rubber article according to claim 1, wherein at least a part of the surface of the cured product is coated with an inert resin layer, and ultraviolet light is irradiated onto the rubber surface that is not coated with the inert resin layer and is exposed.

7. The method for manufacturing a medical rubber article according to claim 6, wherein the inert resin layer is a layer made of a fluororesin.

8. The method for manufacturing a medical rubber article according to claim 6, wherein the inert resin layer is a layer made of a non-fluororesin.

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.

10. The method for manufacturing a medical rubber article according to claim 6, wherein the medical rubber article has a liquid contact surface facing a chemical solution and a sliding surface in contact with a barrel, the liquid contact surface is coated with an inert resin layer, the sliding surface is not coated with an inert resin layer, and the cured product of the medical rubber composition is exposed, and it is a plunger stopper for a syringe.

11. The method for manufacturing a medical rubber article according to claim 10, wherein the inert resin layer is a layer made of a fluororesin.

12. The method for manufacturing a medical rubber article according to claim 10, wherein the inert resin layer is a layer made of a non-fluororesin.

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