Manufacturing method of medical rubber article

Abstract

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

Description

Technical Field

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

Background Art

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

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

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

[0005] Patent Document 2 discloses a surface treatment method of a polymer material substrate by bringing a vinyl compound represented by the general formula (1) R-CH=CH2 (wherein R represents an alkyl group having 6 or more carbon atoms) into contact with the surface of the polymer material substrate (excluding a cloth substrate) and irradiating with ultraviolet rays to impart water repellency to the surface of the polymer material substrate.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] To improve slidability, silicone oil is applied to the surface of medical rubber articles or laminated with a fluororesin film. However, when a medical rubber article coated with silicone oil comes into contact with a biopharmaceutical, protein aggregation may occur due to silicone particles. Therefore, medical rubber articles coated with silicone oil cannot be used for medical supplies that use biopharmaceuticals. In particular, for the plunger stopper of a prefilled syringe, the need for silicone oil-free (SOF) is increasing.

[0008] Also, laminated medical rubber articles laminated with a fluororesin film such as a polytetrafluoroethylene (PTFE) film have an elastic modulus of the PTFE film 100 times higher than that of rubber, and the sealing property tends to decrease as a plunger stopper of a prefilled syringe.

[0009] As a measure to comply with SOF regulations, a method is required to reduce the friction coefficient and adhesiveness of the surface of medical rubber articles without using silicone oil.

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

Means for Solving the Problems

[0011] The manufacturing method of the medical rubber article of the present invention is characterized by including a step of irradiating ultraviolet rays onto a cured product of a medical rubber composition containing halogenated butyl rubber as a base polymer. The inventor has found that by irradiating ultraviolet rays onto a cured product of a medical rubber composition containing halogenated butyl rubber as a base polymer, the surface of the cured product is greatly modified to have a low friction coefficient and low adhesiveness (tack value is almost zero), and thus completed the present invention.

Effects of the Invention

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

Brief Description of the Drawings

[0013]

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Modes for Carrying Out the Invention

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

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

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

[0017] (a) Examples of the halogenated butyl rubber contained in the base polymer include chlorinated butyl rubber, brominated butyl rubber, and brominated products of copolymers of isobutylene and p-methylstyrene. These halogenated butyl rubbers may be used alone or in combination of two or more. As the halogenated butyl rubber, chlorinated butyl rubber or brominated butyl rubber is preferred. The chlorinated butyl rubber or brominated butyl rubber is obtained by adding or substituting chlorine or bromine to the isoprene structural part in butyl rubber, specifically, the double bond and / or the carbon atom adjacent to the double bond. Note that butyl rubber is a copolymer obtained by polymerizing isobutylene and a small amount of isoprene. Note that the halogenated butyl rubber is preferably solid at 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, 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, in the ultraviolet irradiation step, a crosslinking reaction occurs at the chlorinated or brominated isoprene moiety. (a) When the base polymer contains brominated isobutylene-paramethylstyrene copolymer rubber (BIMS) as the halogenated butyl rubber, in the ultraviolet irradiation step, a crosslinking reaction occurs at the brominated paramethylstyrene site.

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

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

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

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

[0024] The medical rubber composition preferably contains (b) a crosslinking agent. The (b) crosslinking agent is compounded 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 a crosslinking agent capable of crosslinking halogenated butyl rubber. Examples of the (b) crosslinking agent include sulfur, metal oxides, resin crosslinking agents, organic peroxides, triazine derivatives, etc., and these can be used alone or in combination of two or more.

[0025] Examples of sulfur used as the crosslinking agent include insoluble sulfur, powdered sulfur, fine powdered sulfur, precipitated sulfur, colloidal sulfur, sulfur chloride, etc.

[0026] Examples of metal oxides used as the crosslinking agent include magnesium oxide, calcium oxide, zinc oxide, copper oxide, etc.

[0027] Examples of resin crosslinking agents include alkylphenol formaldehyde resins such as alkylphenol formaldehyde resins, thermoreactive phenol resins, phenol dialcohol resins, bisphenol resins, thermoreactive bromomethylalkylated phenol resins.

[0028] Specific examples of the organic peroxide include dialkyl peroxide, peroxy ester, peroxy ketal, hydroperoxide, etc. Examples of the dialkyl peroxide include di(2-t-butylperoxyisopropyl)benzene, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylcumyl peroxide, di-t-hexyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, etc. Examples of the peroxy ester include t-butyl peroxymaleate, t-butyl peroxy-3,3,5-trimethylcyclohexanoate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butyl peroxyacetate, t-butyl peroxybenzoate, etc. Examples of the peroxy ketal include 1,1-di(t-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-di(t-hexylperoxy)cyclohexane, 1,1-di(t-butylperoxy)-2-methylcyclohexane, 1,1-di(t-butylperoxy)cyclohexane, 2,2-di(t-butylperoxy)butane, n-butyl-4,4-di(t-butylperoxy)valerate, 2,2-di(4,4-di(t-butylperoxy)cyclohexyl)propane, etc. Examples of the hydroperoxide include p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, etc. These organic peroxides may be used alone or in combination of two or more.

[0029] Examples of the triazine derivative used as the crosslinking agent include compounds represented by the general formula (1).

[0030]

Chemical formula

[0031] [wherein, R is -SH, -OR 1 , -SR 2 , -NHR 3 or -NR 4 R 5 (R 1 , R 2 , R 3 , R 4 and R 5 each represents an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkylaryl group or a cycloalkyl group. R 4 and R 5 may be the same or different. ). M 1 and M 2 are H, Na, Li, K, 1 / 2Mg, 1 / 2Ba, 1 / 2Ca, an aliphatic primary amine, a secondary amine or a tertiary amine, a quaternary ammonium salt or a phosphonium salt. M 1 and M 2 may be the same or different. ]

[0032] In general formula (1), examples of the alkyl group include alkyl groups having 1 to 12 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, tert-pentyl group, n-hexyl group, 1,1-dimethylpropyl group, octyl group, isooctyl group, 2-ethylhexyl group, decyl group, or dodecyl group. Examples of the alkenyl group include alkenyl groups having 1 to 12 carbon atoms such as vinyl group, allyl group, 1-propenyl group, isopropenyl group, 2-butenyl group, 1,3-butadienyl group, or 2-pentenyl group. Examples of the aryl group include monocyclic or condensed polycyclic aromatic hydrocarbon groups, such as aryl groups having 6 to 14 carbon atoms such as phenyl group, naphthyl group, anthryl group, phenanthryl group or acenaphthylenyl group. Examples of the aralkyl group include aralkyl groups having 7 to 19 carbon atoms such as benzyl group, phenethyl group, diphenylmethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 2,2-diphenylethyl group, 3-phenylpropyl group, 4-phenylbutyl group, 5-phenylpentyl group, 2-biphenylylmethyl group, 3-biphenylylmethyl group or 4-biphenylylmethyl group. Examples of the alkylaryl group include alkylaryl groups having 7 to 19 carbon atoms such as tolyl group, xylyl group or octylphenyl group. Examples of the cycloalkyl group include cycloalkyl groups having 3 to 9 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group or cyclononyl group.

[0033] Specific examples of the triazine derivative represented by the general formula (1) include, for example, 2,4,6-trimercapto-s-triazine, 2-methylamino-4,6-dimercapto-s-triazine, 2-(n-butylamino)-4,6-dimercapto-s-triazine, 2-octylamino-4,6-dimercapto-s-triazine, 2-propylamino-4,6-dimercapto-s-triazine, 2-diallylamino-4,6-dimercapto-s-triazine, 2-dimethylamino-4,6-dimercapto-s-triazine, 2-dibutylamino-4,6-dimercapto-s-triazine, 2-di(iso-butylamino)-4,6-dimercapto-s-triazine, 2-dipropylamino-4,6-dimercapto-s-triazine, 2-di(2-ethylhexyl)amino-4,6-dimercapto-s-triazine, 2-dioleylamino-4,6-dimercapto-s-triazine, 2-laurylamino-4,6-dimercapto-s-triazine or 2-anilino-4,6-dimercapto-s-triazine, or sodium salts or disodium salts thereof.

[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 preferable, and 2-dibutylamino-4,6-dimercapto-s-triazine is particularly preferable in view of easy availability.

[0035] In addition, examples of the triazine derivative include one or more of 6-[bis(2-ethylhexyl)amino]-1,3,5-triazine-2,4-dithiol, 6-diisobutylamino-1,3,5-triazine-2,4-dithiol, 6-dibutylamino-1,3,5-triazine-2,4-dithiol, 6-dibutylamino-1,3,5-triazine-2,4-dithiol·monosodium, 6-anilino-1,3,5-triazine-2,4-dithiol, 1,3,5-triazine-2,4,6-trithiol, etc.

[0036] In the medical rubber composition used in the present invention, as the triazine derivative, one type 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 the crosslinking component optimal for crosslinking. When the medical rubber composition contains chlorinated butyl rubber as the halogenated butyl rubber, it is preferable to contain a triazine derivative as the (b) crosslinking agent. Further, when the medical rubber composition contains brominated butyl rubber as the halogenated butyl rubber, it is preferable to contain a metal oxide as the (b) crosslinking agent.

[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, still more preferably 0.6 parts by mass or more, preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and still more preferably 10 parts by mass or less, based on 100 parts by mass of the (a) base polymer component. If the content of the (b) crosslinking agent is within the above range, a rubber having good rubber physical properties (hardness, tensile strength, Cset) and processability (less scorching) can be obtained.

[0039] When 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, still more preferably 0.6 parts by mass or more, preferably 4 parts by mass or less, more preferably 3 parts by mass or less, and still more preferably 2 parts by mass or less, based on 100 parts by mass of the (a) base polymer component. If the content of the (b) crosslinking agent is within the above range, a rubber having good rubber physical properties (hardness, tensile strength, Cset) and processability (less scorching) can be obtained.

[0040] As the halogenated butyl rubber, brominated butyl rubber is used. When a metal oxide is used as the crosslinking agent (b), the content of the crosslinking agent (b) in the medical rubber composition is preferably 1 part by mass or more, more preferably 1.5 parts by mass or more, still more preferably 2 parts by mass or more, preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and still more preferably 10 parts by mass or less with respect to 100 parts by mass of the base polymer component (a). If the content of the crosslinking agent (b) is within the above range, a rubber with good rubber physical properties (hardness, tensile strength, C set) and processability (less scorching) 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 elute into the chemical solution in a syringe or the like. Examples of the vulcanization accelerator include guanidine-based accelerators (e.g., diphenylguanidine), thiuram-based accelerators (e.g., tetramethylthiuram disulfide, tetramethylthiuram monosulfide), dithiocarbamate-based accelerators (e.g., zinc dimethyldithiocarbamate), thiazole-based accelerators (e.g., 2-mercaptobenzothiazole, dibenzothiazyl disulfide), and sulfenamide-based accelerators (N-cyclohexyl-2-benzothiazole sulfenamide, N-t-butyl-2-benzothiazole sulfenamide).

[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 the crosslinking of the halogenated butyl rubber and prevent the occurrence of crosslinking inhibition and the like caused by these gases. In addition, the acid acceptor functions as a scorch inhibitor during the crosslinking of the halogenated butyl rubber and also functions to prevent an increase in the compression set of medical rubber parts.

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

[0044] Examples of hydrotalcite include Mg4.5 Al2(OH) 13 CO3·3.5H2O, Mg 4.5 Al2(OH) 13 CO3, Mg4Al2(OH) 12 CO3·3.5H2O, Mg6Al2(OH) 16 CO3·4H2O, Mg5Al2(OH) 14 CO3·4H2O, Mg3Al2(OH) 10 Examples of the Mg - Al - based hydrotalcite include Mg - Al - based hydrotalcite such as Al2(OH)CO3·3.5H2O, Mg, Al2(OH)CO3, Mg4Al2(OH)CO3·3.5H2O, Mg6Al2(OH)CO3·4H2O, Mg5Al2(OH)CO3·4H2O, Mg3Al2(OH)CO3·1.7H2O, etc. Examples of the metal oxide include magnesium oxide, calcium oxide, zinc oxide, etc. Examples of the metal hydroxide include calcium hydroxide, etc. These acid acceptors may be used alone or in combination of two or more. Note that the metal oxide used as the cross - linking agent described above can also function as an acid acceptor.

[0045] The content of the acid acceptor is preferably 0.5 part by mass or more, more preferably 1 part by mass or more, preferably 15 parts by mass or less, and more preferably 10 parts by mass or less with respect to 100 parts by mass of the base polymer component (a). If the content of the acid acceptor is within the above range, the generation of rust on molds, etc. can be suppressed, and the problem that the raw material itself becomes white - dot foreign matter can be reduced.

[0046] The medical rubber composition may further contain a filler. Examples of the filler include inorganic fillers such as clay and talc. Among these, as the filler, an inorganic filler is preferred, and clay or talc is more preferred. The filler functions to adjust the rubber hardness of the medical rubber parts and also functions to reduce the production cost of the medical rubber parts as a bulking agent.

[0047] Examples of the clay include fired clay and kaolin clay. Specific examples of the clay include, for example, SILLITIN (registered trademark) Z manufactured by HOFFMANN MINERAL, SATINTONE (registered trademark) W manufactured by ENGELHARD, NN kaolin clay manufactured by Tsuchiya Kaolin Industry Co., Ltd., PoleStar200R manufactured by Imerys Specialties Japan Co., Ltd., and the like.

[0048] Specific examples of the talc include, for example, Hytron A manufactured by Takehara Chemical Industry Co., Ltd., MICRO ACE (registered trademark) K-1 manufactured by Nippon Talc Co., Ltd., Mistron (registered trademark) Vapor manufactured by Imerys Specialties Japan Co., Ltd., and the like.

[0049] The content of the filler in the medical rubber composition is preferably set appropriately according to the rubber hardness and the like of the target medical rubber article. The content of the filler in the medical rubber composition is, for example, preferably 5 parts by mass or more, more preferably 10 parts by mass or more, still more preferably 20 parts by mass or more, preferably 200 parts by mass or less, more preferably 150 parts by mass or less, and still more preferably 100 parts by mass or less with respect to 100 parts by mass of the base polymer component.

[0050] The medical rubber composition may further be blended with a coloring agent such as titanium oxide and carbon black, a lubricant such as stearic acid, a processing aid, polyethylene glycol as a crosslinking activator, a process oil, and the like at an appropriate ratio.

[0051] The medical rubber composition is obtained by kneading (a) a base polymer, (b) a crosslinking agent, and other compounding materials added as necessary. Kneading can be performed using, for example, an open roll, a closed kneader, or the like. The kneaded product is preferably formed into a ribbon shape, a sheet shape, a pellet shape, or the like, and more preferably formed into a sheet shape.

[0052] The manufacturing method of the 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. By press-molding a ribbon-shaped, sheet-shaped, or pellet-shaped kneaded product, a cured product of the medical rubber composition having a desired shape can be obtained. The crosslinking reaction of the medical rubber composition proceeds during pressing. The molding temperature is preferably, for example, 130 °C or higher, more preferably 140 °C or higher, preferably 200 °C or lower, and more preferably 190 °C or lower. The molding time is preferably 2 minutes or longer, more preferably 3 minutes or longer, preferably 60 minutes or shorter, and more preferably 30 minutes or shorter. The molding pressure is preferably 0.1 MPa or higher, more preferably 0.2 MPa or higher, preferably 10 MPa or lower, and more preferably 8 MPa or lower.

[0053] At least a part of the surface of the cured product of the medical rubber composition to which the present invention is applied may be coated with an inert resin layer. For example, by press-molding in a state where an inert resin film is laminated on a sheet composed of a medical rubber composition, at least a part of the surface of the cured product of the medical rubber composition is coated with an inert resin layer.

[0054] The inert resin layer only needs to cover at least a part of the surface of the medical rubber article, and it is preferably laminated appropriately according to the form of the medical rubber article. In particular, it is preferable to provide an inert resin layer on the surface of the medical rubber article that comes into contact with the drug. In this aspect, the inert resin layer exhibits good chemical resistance, and the slidability of the surface where the inert resin layer is not provided can be improved by ultraviolet irradiation.

[0055] The resin constituting the inert resin layer is not particularly limited, but from the viewpoint of obtaining good chemical resistance, at least one fluororesin selected from the group consisting of tetrafluoroethylene-ethylene copolymer (ETFE), polytetrafluoroethylene (PTFE), and polychlorotetrafluoroethylene (PCTFE), or a non-fluororesin can be mentioned.

[0056] Tetrafluoroethylene-ethylene copolymer (ETFE) is a copolymer of ethylene and tetrafluoroethylene with a molar ratio of 30 / 70 to 70 / 30. There is also modified ETFE obtained by copolymerizing other components for modification purposes. Examples of other components include fluorine-containing olefins and hydrocarbon-based 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, etc. are copolymerized in an amount of about 2 to 10 mol% to modify ETFE.

[0057] As the modified ETFE, ETFE having a functional group capable of imparting adhesiveness can be preferably used. Examples of the functional group include carboxyl group, carboxyl anhydride group, epoxy group, hydroxyl group, isocyanate group, ester group, amide group, aldehyde group, amino group, cyano group, carbon-carbon double bond, sulfonic acid group, ether group, etc. Commercially available products of modified ETFE include Fluon AH-2000 manufactured by Asahi Glass Co., Ltd.

[0058] Examples of non-fluorine resins include olefin resins. Examples of the olefin resins include polyethylene 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 resins such as polypropylene, propylene-ethylene random copolymer, propylene-ethylene block copolymer, and chlorinated polypropylene, polybutene, polyisobutylene, polymethylpentene, copolymers of cyclic olefins, etc. Polyethylene (especially ultra-high molecular weight polyethylene (UHMWPE)) is preferred. Also, the olefin resin may contain fluorine.

[0059] The thickness of the inert resin film to be used may be appropriately adjusted according to the shape and size of the medical rubber article, but is preferably 10 μm or more, more preferably 20 μm or more, still more preferably 30 μm or more, preferably 150 μm or less, more preferably 130 μm or less, and still more preferably 110 μm or less. If the thickness of the inert resin film is within the above range, film breakage during product molding and defects such as wrinkles and floating on the film surface of the molded product will not occur, and both molding processability and product characteristics can be achieved.

[0060] The arithmetic mean roughness Ra of the inert resin film can be from 0.01 to 0.03 μm for casting films and extrusion films, or 0.10 μm for skiving films. By making the surface roughness of the mold 0.03 μm or less, a medical rubber article excellent in liquid tightness and airtightness can be obtained. The lower limit of Ra of the inert film itself is not particularly limited.

[0061] It is preferable to perform a treatment for enhancing the adhesiveness of the inert resin film to rubber or the like. Examples of the treatment for enhancing the adhesiveness include chemical treatment methods, treatments for roughening the surface of the film, and combinations thereof. 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 manufacturing the medical rubber article of the present invention includes a step of irradiating the cured product of the medical rubber composition with ultraviolet rays (ultraviolet irradiation step). The cured product of the medical rubber composition to be irradiated with ultraviolet rays may be in the shape of the final medical rubber article, or may be a preform before being formed into the shape of the final medical rubber article.

[0063] The method for irradiating the cured product of the medical rubber composition with ultraviolet rays is not particularly limited. For example, it may be irradiated onto the surface of the cured product of the medical rubber composition using a light source that emits ultraviolet rays.

[0064] The wavelength of the ultraviolet ray is preferably 160 nm or more, more preferably 165 nm or more, and still more preferably 170 nm or more. This is because surface modification can be achieved when the wavelength of the ultraviolet ray is 160 nm or more. Further, the upper limit of the wavelength of the ultraviolet ray is not particularly limited, but is preferably 380 nm or less, more preferably 300 nm or less, and still more preferably 200 nm or less. When the wavelength of the ultraviolet ray is 380 nm or less, the energy of the ultraviolet ray becomes high, the crosslinking efficiency of the butyl rubber halide becomes high, and it becomes difficult to deform. Further, low molecular components that contribute to the surface tackiness of the cured product of the medical rubber composition are decomposed and evaporated by high-energy ultraviolet rays, and low tackiness can be realized. Furthermore, due to the evaporation of the low molecular components, the surface of the cured product becomes rough, so that the coefficient of friction can be further reduced. Among these, vacuum ultraviolet rays having a wavelength of 200 nm or less are particularly preferable from the viewpoint of obtaining better effects of the present invention.

[0065] The light source that emits the ultraviolet ray 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, or the like is used. In particular, an excimer lamp is preferable because it has strong energy and surface modification can be performed in a relatively short time. The excimer lamp emits ultraviolet rays with different wavelengths depending on the type of discharge gas used. For example, when xenon (Xe2) is used, it emits ultraviolet rays (also called "excimer UV light") having a central wavelength of 172 nm, when xenon chloride (XeCl) is used, it emits ultraviolet rays having a central wavelength of 308 nm, when xenon bromide (XeBr) is used, it emits ultraviolet rays having a central wavelength of 283 nm, when xenon iodide (XeI) is used, it emits ultraviolet rays having a central wavelength of 253 nm, when argon fluoride (ArF) is used, it emits ultraviolet rays having a central wavelength of 193 nm, when argon bromide (ArBr) is used, it emits ultraviolet rays having a central wavelength of 165 nm, when krypton chloride (KrCl) is used, it emits ultraviolet rays having a central wavelength of 222 nm, and when krypton bromide (KrBr) is used, it emits ultraviolet rays having a central wavelength of 207 nm. In the present invention, an excimer lamp that emits vacuum ultraviolet rays having a central wavelength of 200 nm or less is preferable, and an excimer lamp using xenon (central wavelength: 172 nm) is particularly preferable.

[0066] In the ultraviolet irradiation step, the integrated illuminance of ultraviolet rays on the cured product of the medical rubber composition is preferably 1000 mJ / cm 2 or more, more preferably 3000 mJ / cm 2 or more, and even more preferably 5000 mJ / cm 2 or more. If the integrated illuminance of ultraviolet rays on the cured product of the medical rubber composition is 1000 mJ / cm 2 or more, the crosslinking of the halogenated butyl rubber is sufficiently carried out, and the low molecular components contributing to the surface tackiness of the cured product of the medical rubber composition are more easily decomposed. Further, the upper limit of the integrated illuminance of ultraviolet rays on the cured product of the medical rubber composition is not particularly limited, but it is preferably 50000 mJ / cm 2 or less, more preferably 45000 mJ / cm 2 or less, and even more preferably 40000 mJ / cm 2 or less. If the integrated illuminance of ultraviolet rays on the cured product of the medical rubber composition is 50000 mJ / cm 2 or less, the balance between the life of the irradiation equipment and the efficiency of surface modification can be achieved. The integrated illuminance of ultraviolet rays on the cured product of the medical rubber composition is the total illuminance (arrival illuminance) of ultraviolet rays reaching the surface of the cured product of the medical rubber composition, and can be calculated by multiplying the intensity of the ultraviolet rays reaching the surface of the cured product of the medical rubber composition (arrival intensity) by the irradiation time of the ultraviolet rays.

[0067] The arrival intensity and irradiation time of the ultraviolet rays may be appropriately adjusted so as to obtain the integrated illuminance within the above-described range. Usually, the arrival intensity of the ultraviolet rays is 10 mW / cm 2 / sec to 100 mW / cm 2 / sec, and the irradiation time is preferably 10 seconds to 5000 seconds. By setting the arrival intensity and irradiation time of the ultraviolet rays within these ranges, it is easier to obtain the integrated illuminance within the above-described range.

[0068] The distance between the surface of the cured product of the medical rubber composition and the light source (lamp) that emits ultraviolet rays is not particularly limited, but from the viewpoint of enhancing the uniformity of ultraviolet irradiation, it is preferably 1 mm to 20 mm.

[0069] In the present invention, by irradiating the cured product of the medical rubber composition with ultraviolet rays, the surface of the cured product can be greatly modified to have a low coefficient of friction and low adhesiveness.

[0070] In the production method of the present invention, when at least a part of the surface of the cured product of the medical rubber composition is covered with an inert resin layer, it is preferable to irradiate the rubber surface that is not covered with the inert resin layer and is exposed with ultraviolet rays. Ultraviolet rays may be irradiated only on a part of the exposed rubber surface, or may be irradiated on the entire exposed rubber surface.

[0071] The production method of the medical rubber article of the present invention may include a step of processing the cured product of the medical rubber composition into a predetermined shape, a step of washing, a step of sterilizing, and a step of drying. For example, from the cured product of the medical rubber composition after ultraviolet irradiation, unnecessary portions are cut and removed to form a predetermined shape, and then washed, sterilized, dried, and packaged to produce a medical rubber article. Note that cutting and removing unnecessary portions to form a predetermined shape may be performed before irradiating the cured product of the medical rubber composition with ultraviolet rays.

[0072] The medical rubber article obtained by the production method of the present invention can achieve a low coefficient of friction and low adhesiveness without using silicone oil. Therefore, the medical rubber article of the present invention can be suitably used as a medical rubber article that requires a low coefficient of friction and low adhesiveness while conforming to the SOF regulation.

[0073] From the viewpoint of SOF compliance, it is preferable that the medical rubber article obtained by the production method of the present invention is not coated with silicone oil. Examples of the silicone oil include dimethylpolysiloxane, methylphenylpolysiloxane, and modified products thereof.

[0074] Examples of the medical rubber articles obtained by the production method of the present invention include rubber stoppers and seal members for containers for various drugs such as liquid agents, powder preparations, and freeze-dried preparations, rubber stoppers for evacuated blood collection tubes, plunger stoppers (gaskets) for prefilled syringes, or sliding or sealing parts such as nozzle caps. Among these, medical rubber articles (for example, rubber stoppers and plunger stoppers) that require a low coefficient of friction and low adhesiveness are preferred, and plunger stoppers that require excellent slidability are particularly preferred.

[0075] Among these, the rubber stoppers and seal members including those for vials and infusion preparation containers preferably have a durometer type A hardness (Shore A hardness) of 35 or more and preferably 60 or less, as measured according to the measurement method described in Japanese Industrial Standard JIS K6253-3:2012 "Vulcanized Rubber and Thermoplastic Rubber - Method for Determining Hardness - Part 3: Durometer Hardness".

[0076] Also, the sliding or sealing parts such as gaskets for prefilled syringes and nozzle caps preferably have the above Shore A hardness of 40 or more and preferably 70 or less.

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

[0078] Hereinafter, specific examples of the medical rubber article to which the present invention is applied will be described. <Plunger Stopper> FIG. 1 is a diagram showing in an exploded state a medical syringe in which the medical rubber article of the present invention is used, that is, a syringe called a prefillable syringe 30. In FIG. 1, the syringe barrel 31 and the plunger stopper 33 are each shown in cross-section for half of their length. The prefillable syringe 30 includes a cylindrical syringe barrel 31, a plunger 32 combined with the syringe barrel 31 and capable of reciprocating within the syringe barrel 31, and a plunger stopper 33 attached to the tip of the plunger 32.

[0079] The plunger 32 is composed of, for example, a resin plate piece with a cross-section in a cross shape, and is provided with a head portion 38 to which a plunger stopper 33 is attached at its tip. The head portion 38 is made of resin integrally formed with the plunger 32 and is processed into a male screw shape. The plunger stopper 33 has a substantially cylindrical shape with a short axis, and its tip surface has, for example, a blunt-angle mountain shape with the axial center portion protruding. And a fitting recess 35 with a female screw shape engraved axially from the rear end surface is formed. By screwing the head portion 38 of the plunger 32 into the fitting recess 35 of the plunger stopper 33, the plunger stopper 33 is attached to the tip of the plunger 32.

[0080] Figure 2 is a half-sectional front view of an example of a plunger stopper. The plunger stopper 40 includes a main body 41 made of a cured product of a medical rubber composition and an inert resin layer 42 covering a part of the surface of this main body. The plunger stopper 40 has a liquid contact surface portion 47 facing the chemical solution and a sliding surface portion 46 in contact with the syringe barrel.

[0081] In the aspect shown in Figure 2, when the plunger stopper 40 is inserted into the syringe barrel, only the mountain-shaped liquid contact surface portion 47 in contact with the chemical solution is covered with the inert resin layer 42. As the inert resin layer 42, for example, a polytetrafluoroethylene film is preferable.

[0082] The sliding surface portion (outer peripheral surface) 46 where the plunger stopper 40 contacts the syringe barrel is not provided with the inert resin layer 42 and is irradiated with ultraviolet rays. The sliding surface portion (outer peripheral surface) 46 has high slidability.

[0083] The plunger stopper 40 has a short cylindrical shape and has a plurality of annular ribs 43, 44, 45 on the outer circumferential surface 46 of the cylindrical shape. The annular ribs are in sliding contact with the inner circumferential surface of the syringe barrel. The plurality of annular ribs are arranged in the axial direction from the tip end surface (liquid contact portion) 47 to the rear end surface 48 of the plunger stopper. The number of annular ribs is not particularly limited as long as it is 1 or more, but it is preferably 2 or more, more preferably 3 or more, preferably 6 or less, more preferably 5 or less, and even more preferably 4 or less.

[0084] The plunger stopper 40 in Fig. 2 has a first annular rib 43, a second annular rib 44, and a third annular rib 45 from the tip end side. The first annular rib 43 at the tip end 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 by the following formula from the outer diameter D1 of the annular rib in the uncompressed state and the inner diameter R of the syringe barrel. Compression rate (%) = 100×(D1 - R) / D1

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

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

[0087] Incidentally, the plunger stopper may be referred to as a stopper or a gasket.

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

[0089] The medical plug body 50 has a top plate 53 and a cylindrical leg portion 55 extending downward from the lower surface of the top plate 53. The top plate 53 and the leg portion 55 are made of a cured product of a rubber composition. The leg portion 55 fits into the mouth portion of the medical container when the medical container is stoppered with the medical plug body of the present invention. In FIG. 3(b), the opposing inner surfaces of the cylindrical leg portion 55 are tapered so that the distance between the inner surfaces of the leg portion gradually decreases from bottom to top (toward the top surface side).

[0090] The top plate 53 is circular in plan view. The top plate 53 has a puncture portion 53a that allows a syringe injection needle to be punctured, and a flange portion 53b that contacts the upper edge surface of the mouth portion of the medical container when the medical container is stoppered.

[0091] On the top surface side of the flange portion 53b, a protrusion 57 is provided to prevent adhesion to other rubber stoppers.

[0092] The puncture portion 53a is an area for inserting an injection needle to aspirate the chemical solution inside the container on the top plate 53. The puncture portion 53a is circular in plan view and is located at the center of the top plate 53. Further, the puncture portion 53a is formed in a concave shape from the top surface.

[0093] In the embodiment of FIG. 3, the entire lower surface of the top plate 53 and the surface of the leg portion 55 are covered with an inert resin layer 59. Incidentally, the inert resin layer 59 may cover at least a part of the lower surface of the top plate 53 and the surface of the leg portion 55. As the inert resin layer 59, a polytetrafluoroethylene film is preferable.

[0094] The upper surface of the top plate 53 is not provided with an inert resin layer and is irradiated with ultraviolet rays. Since the friction coefficient and adhesiveness of the upper surface of the top plate 53 are reduced, the problem of rubber stoppers sticking to each other is improved.

[0095] FIG. 4 is an explanatory view showing another aspect of the medical rubber stopper 50 to which the present invention is applied. FIG. 4(a) is a plan view, and FIG. 4(b) is a cross-sectional view taken along line B-B in FIG. 4(a). In the medical rubber stopper 50 of FIG. 4, the description of the parts having the same configuration as in FIG. 3 is omitted.

[0096] The medical rubber stopper 50 of this aspect has bifurcated legs 55 extending from the lower surface 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 side). In the aspect of FIG. 4, the top plate 53 and the legs 55 are composed of a cured product of a rubber composition, and the entire lower surface of the top plate 53 and the surface of the legs 55 are covered with an inert resin layer 59. Note that the inert resin layer 59 may cover at least a part of the lower surface 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 inert resin layer and is irradiated with ultraviolet rays. Since the friction coefficient and adhesiveness of the upper surface of the top plate 53 are reduced, the problem of rubber stoppers sticking to each other is improved.

[0098] A nylon film layer may be provided on the top surface of the top plate 53 of the medical rubber stopper 50 in FIGS. 3 and 4. By providing a nylon film layer on the top surface of the medical rubber stopper 50, the mechanical transportability during pharmaceutical production can be ensured. Also, 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, and the generation of needle puncture fragments can be prevented during injection needle puncture.

[0099] <Rubber stopper for vacuum blood collection tube> FIG. 5 is an explanatory diagram showing an example of a vacuum blood collection tube. The vacuum blood collection tube 90 includes a bottomed tube 91 and a rubber stopper 93 that seals the opening of the bottomed tube 91. It is designed to automatically collect blood by reducing the pressure inside the blood collection tube.

[0100] FIG. 6 is an explanatory diagram for explaining an example of a medical plug body to which the present invention is applied. It is an explanatory diagram showing 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 of the vacuum blood collection tube has a top plate 94 and a cylindrical leg portion 95 extending downward from the lower surface of the top plate 94. The top plate 94 and the leg portion 95 are made of an elastic body. The leg portion 95 fits into the mouth of the vacuum blood collection tube when the vacuum blood collection tube is plugged with the rubber stopper. A puncture portion 96, which is an area for inserting an injection needle, is provided at the center of the top plate 94. The puncture portion 96 is formed in a concave shape from the top surface. The entire lower surface of the top plate 94 and the surface of the leg portion 95 are covered with an inert resin layer 97. Note that the inert resin layer 97 may cover at least a part of the lower surface 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 inert resin layer and is irradiated with ultraviolet rays. Since the friction coefficient and adhesiveness of the upper surface of the top plate 94 are reduced, the problem of the rubber stopper bodies sticking to each other is improved.

[0102] <Nozzle cap> FIG. 7(a) is a cross-sectional view showing an example of a nozzle cap of a medical syringe and a nozzle of a syringe barrel to be covered therewith. FIG. 7(b) is a cross-sectional view showing a state where the nozzle cap is put on 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 puncture portion 87 connected to one end side (upper end side in the figure) of the cylindrical portion 86. The needle puncture portion 87 is formed in a columnar shape having an outer surface continuous with the cylindrical portion 86. An opening 88 is provided at the other end side (lower end side in the figure) of the cylindrical portion 86 for inserting the nozzle 83 into the cylindrical portion 86 to cover the nozzle 83 with the nozzle cap 81. The inner surface of the nozzle cap 81 and the surface of the lower end portion of the cylindrical portion 86 are covered with an inert resin layer 84.

[0103] The outer surface of the nozzle cap 81 is not provided with an inert resin layer and is irradiated with ultraviolet rays. Since the friction coefficient and adhesiveness of the outer surface of the nozzle cap 81 are reduced, the problem of the nozzle caps sticking to each other is improved.

Example

[0104] Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited by the following examples, and any changes and embodiments within the scope not departing from the gist of the present invention are all included in the scope of the present invention.

[0105] [Production of Medical Rubber Articles] The materials shown in Table 1 were kneaded at 60° C. for 20 minutes using an open roll to prepare a medical rubber composition. The obtained medical rubber composition was cross-linked under the molding conditions of 170° C. for 15 minutes, and then punched out into a circular slab having a diameter of 28 mm and a thickness of 2 mm to obtain a test piece for ultraviolet irradiation (a cured product of the medical rubber composition). The test piece for ultraviolet irradiation was irradiated with vacuum ultraviolet rays (wavelength: 172 nm) so as to obtain the integrated illuminance shown in Table 1. Irradiation Conditions of Ultraviolet Rays · Irradiation device: Electrodeless excimer 172 nm irradiation device (manufactured by M.D. Com Co., Ltd.) · Distance between the surface of the hardened material and the lamp: 7 mm · Intensity of ultraviolet light reaching: 57.9 mW / cm 2 / sec

[0106]

Table 1

[0107] Details of the compounding materials used are as follows. Chlorinated butyl rubber: Exxon (registered trademark) Chlorobutyl 1066 manufactured by ExxonMobil (chlorine content rate: 1.25 wt%) General-purpose butyl rubber: Exxon (registered trademark) Butyl 268 manufactured by ExxonMobil (degree of unsaturation: 2.30 mol%) Triazine derivative: Disnet DB manufactured by Sankyo Kasei Co., Ltd. Sulfur: Insoluble sulfur (Seimi OT) manufactured by Nippon Kouryū Kōgyō Co., Ltd. Zinc oxide: Activated zinc white AZO manufactured by Shōdō Chemical Industry Co., Ltd. Magnesium oxide: Mag-Sarat 150s manufactured by Kyowa Chemical Industry Co., Ltd. Dithiocarbamate: Nocceler (registered trademark) ZTC manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

[0108] [Evaluation method] (1) Coefficient of friction (Measurement of static friction coefficient and kinetic friction coefficient) Figure 8 is an explanatory diagram showing a method for measuring the coefficient of friction using a coefficient of friction measuring machine TL201 (manufactured by TAILAB) for the medical rubber article (circular slab with a thickness of 2 mm and a diameter of 28 mm after ultraviolet irradiation) prepared above. The measurement sample 63 is fixed to the lower stage 64, and a 10 g weight 61 is placed on a dedicated probe with a SUS ball 62 having a diameter of 10 mm to bring the surface of the measurement sample 63 into contact with the SUS ball 62. Then, the stage 64 is moved in the direction of the arrow at a speed of 10 mm / second for a distance of 20 mm. The value obtained by dividing the frictional force F generated at that time by the load (vertical resistance) N was defined as the coefficient of friction μ. (μ = F / N) The coefficient obtained by dividing by the average vertical resistance N1 at a moving distance of 20 mm was defined as the coefficient of kinetic friction, and the coefficient obtained by dividing by the maximum average vertical resistance N2 at a moving distance of 20 mm was defined as the coefficient of static friction. <Evaluation of Coefficient of Static Friction> The coefficient of static friction was evaluated according to the following evaluation criteria. ○: The coefficient of static friction is less than 1.50. △: The coefficient of static friction is 1.50 or more and less than 3.3. ×: The coefficient of static friction is 3.3 or more. A coefficient of static friction less than 3.3 was considered a pass. <Evaluation of Coefficient of Kinetic Friction> The coefficient of kinetic friction was evaluated according to the following evaluation criteria. ○: The coefficient of kinetic friction is less than 1.30. △: The coefficient of kinetic friction is 1.30 or more and less than 2.00. ×: The coefficient of kinetic friction is 2.00 or more. A coefficient of kinetic friction less than 2.00 was considered a pass.

[0109] (2) Adhesion Test <Measurement of Tack Value> Regarding the medical rubber article prepared above (circular slab with a thickness of 2 mm and a diameter of 28 mm after ultraviolet irradiation), using a testing machine EZ-SX (manufactured by Shimadzu Corporation), the medical rubber article was fixed to the dedicated jig on the lower side, the upper metal Φ10 mm SUS probe was pressed against the surface of the medical rubber article, after reaching the set pressure (10 N), it was held for 10 seconds, raised upward at a speed of 10 mm / second, and 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. n = 5 was measured, and the average value of n = 3 excluding the maximum and minimum was taken as the tack value. <Evaluation of Adhesion> The adhesion was evaluated according to the following evaluation criteria. 〇: The tack value is 0.55 N or less. ×: The tack value exceeds 0.55 N.

[0110] (3) Comprehensive Evaluation 〇: The evaluation results of the friction coefficient and the evaluation results of the adhesion are 〇 or △. ×: Both the evaluation result of the friction coefficient and the evaluation result of the adhesiveness are ×.

[0111] Table 1 shows the measurement results and evaluation results of the friction coefficient and adhesiveness. From Table 1, it can be seen that the medical rubber article obtained by the production method of the present invention has a reduced surface friction coefficient and adhesiveness.

Industrial Applicability

[0112] The surface modification method of the present invention can provide a medical rubber part with 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 slidability).

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

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

[0115] A preferred embodiment (3) of the present invention is a method for producing a medical rubber article according to embodiment (1) or (2), wherein the integrated illuminance of the ultraviolet rays on the cured product is 1000 mJ / cm 2 ~50000 mJ / cm 2 A preferred embodiment (4) of the present invention is a 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 brominated products of copolymers of isobutylene and p-methylstyrene.

[0116] A preferred embodiment (5) of the present invention is a method for producing a medical rubber article according to any one of embodiments (1) to (4), wherein the base polymer (a) consists only of halogenated butyl rubber.

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

[0118] A preferred embodiment (6) of the present invention is a method for manufacturing a medical rubber article according to any one of embodiments (1) to (5), wherein at least a part of the surface of the cured product is coated with an inert resin layer, and ultraviolet rays are irradiated onto the exposed rubber surface that is not coated with the inert resin layer.

[0119] A preferred embodiment (7) of the present invention is a method for manufacturing a medical rubber article according to embodiment (6), wherein the inert resin layer is a layer made of a fluororesin.

[0120] A preferred embodiment (8) of the present invention is a method for manufacturing a medical rubber article according to embodiment (6), wherein the inert resin layer is a layer made of a non-fluororesin.

[0121] A preferred embodiment (9) of the present invention is a method for manufacturing a medical rubber article according to any one of embodiments (1) to (8), wherein the medical rubber article is a rubber stopper for a vial, a cap for a syringe, a plunger stopper, or a rubber stopper for a vacuum blood collection tube.

[0122] A preferred embodiment (10) of the present invention is a method for manufacturing a medical rubber article according to embodiment (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 the inert resin layer, and the cured product of the medical rubber composition is exposed, and it is a plunger stopper for a syringe.

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

[0124] A preferred embodiment (12) of the present invention is a method for manufacturing a medical rubber article according to embodiment (10), wherein the inert resin layer is a layer made of a non-fluororesin.

Claims

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

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 copolymers of isobutylene and p-methylstyrene.

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