JPS6220825B2 - - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to radiation sterilizable medical instruments. More specifically, the present invention relates to a radiation sterilizable medical device comprising a composition comprising a propylene polymer blended with a stabilizer and a nucleating agent. Propylene polymers are widely used in medical instruments, especially disposable medical instruments such as syringes, needle bases, infusion/blood transfusion sets, and blood sampling instruments due to their characteristics such as rigidity and impact strength. However,
Propylene polymer products undergo deterioration and deterioration due to radiation sterilization.
It has the disadvantage of discoloration. That is, when a propylene polymer is irradiated with radiation of 2 to 4 megarads, decomposition and deterioration reactions occur, resulting in discoloration of the product, generation of cracks, and reduction in impact strength. Furthermore, problems such as the elution of stabilizers blended into the polymer for the purpose of preventing oxidation, removing radicals, and other purposes, causing odor, and significant coloring occur.
When the medical device is an injection molded product, the above deterioration due to radiation irradiation is particularly noticeable. Prior Art and Problems Several methods have already been reported for improving the radiation resistance of propylene polymer products. Namely, there are methods of blending various phenol-based, phosphorus-based or sulfur-based compounds as stabilizers into propylene polymers (Japanese Patent Application Laid-open No. 49-39637), methods of blending hindered amines (Japanese Patent Application Laid-open No. 55-19199), and A method of blending an amorphous additive into a propylene polymer with a narrow molecular weight distribution (US Patent No. 4274932)
No.) has been proposed. Although these methods have considerably improved the radiation resistance of propylene polymers, there are still points to be improved. In other words, in the method of blending phenol-based, phosphorus-based, or sulfur-based compounds, there are practical problems in terms of color resistance and heat deterioration resistance, as well as the phenomenon of elution into the contents that come into contact with the molded product. . Tokukai Sho mentioned above
For example, the one described in No. 49-39637 to which tetrakis[methylene (3,5-di-tert-butylhydroxyhydrocinnamate)]methane was added was significantly colored by 2.5 megarad gamma ray irradiation, and the 1,1,3- Those to which tris(2-methyl-5-tert-butyl-4-hydroxyphenyl)butane is added have insufficient heat resistance after irradiation. In the method of adding hindered amine,
The hindered amine described in JP-A-55-19199, such as sebacic acid di-(2,2,6,6-tetramethyl-4-piperidyl), may cause the cytotoxic substance to elute or the additive to dissolve over time. There is a problem of bleeding on the surface of the molded product. Furthermore, when a hindered amine is added alone, the molecular weight decreases during molding, resulting in a large decrease in strength. Furthermore, the method of blending an amorphous additive into a propylene polymer with a narrow molecular weight distribution does not sufficiently prevent deterioration, and there are problems in terms of bleeding of the additive, toxicity, etc., and it is not practical. In this way, the methods reported so far are
All of them had some kind of drawback and were difficult to implement commercially. Furthermore, it is common practice to add a nucleating agent to a propylene polymer composition to improve the transparency of the product. However, among the conventionally used nucleating agents, dibenzylidene sorbitol, which has an excellent transparency improvement effect, decomposes when exposed to radiation and generates an odor, so radiation sterilization of medical instruments to which this nucleating agent is added is difficult. There was a problem. OBJECTS OF THE INVENTION Accordingly, an object of the present invention is to provide a propylene polymer medical device that can be commercially sterilized by radiation irradiation. In other words, the present invention provides a transparent material that retains the characteristics of propylene polymers such as transparency and impact strength even after radiation sterilization, and also satisfies all safety and hygiene issues such as toxicity and odor generation. Its purpose is to provide medical equipment. DETAILED DESCRIPTION OF THE INVENTION The present invention comprises medical instruments as described in each of the following items 1 to 13. (1) To 100 parts by weight of a propylene polymer having a ratio of weight average molecular weight to number average molecular weight of 5 or less, 0.01 to 0.4 parts by weight of a hindered amine represented by the following formula [] or [] as a stabilizer and the following formula [], Phenol or its phosphite compound represented by [] or []0.01~
A radiation sterilizable medical device, characterized in that it is a molded article comprising a composition containing 0.4 parts by weight and 0.01 to 0.4 parts by weight of a compound represented by the following formula [] as a nucleating agent. In the above formula, R ₁ is an alkyl group having 1 to 12 carbon atoms, R ₂ is an alkyl group having 3 to 12 carbon atoms, R ₃ is an alkyl group having 1 to 18 carbon atoms, and X is a hydrogen atom or a group.

[Formula] (R ₄ in the group represents an alkyl group having 1 to 30 carbon atoms), Y is a divalent hydrocarbon group having 1 to 18 carbon atoms or a sulfur atom, and Z has a carbonyloxy group embedded therein. _R5 and _R6 are alkyl or alkoxy groups, hydroxyl groups or halogen atoms having 1 to 8 carbon atoms, k is an integer of 1 to 10, l is m is an integer of 1 to 6, _n1 and _n2 are each independently an integer of 1 to 3, and p is 0 or 1. (2) The ratio of weight average molecular weight to number average molecular weight is 2.5~
4.8, 0.03 to 0.3 parts by weight of a hindered amine represented by the above formula [] or [] as a stabilizer, and a phenol or its phosphorous represented by the above formula [], [] or []. acid ester compound
The medical device according to item 1 above, which is a molded article comprising a composition containing 0.02 to 0.2 parts by weight and 0.05 to 0.3 parts by weight of the compound represented by the formula [] as a nucleating agent. (3) The medical device according to item 1 or 2 above, wherein the hindered amine is a compound in which R ₁ is a methyl group and k is 3 or 4 in the formula []. (4) The medical device according to item 1 or 2 above, wherein the hindered amine is a compound in which R ₁ is a methyl group and l is 2 in the formula []. (5) The above phenol compound is a compound represented by the formula [], where R ₂ is a t-butyl group (5th position), R ₃ is a methyl group (2nd position), X is a hydrogen atom, and m is 1. The medical device according to any one of Items 1 to 4. (6) The above-mentioned phenol phosphite compound is represented by the above formula [], and R ₂ is a t-butyl group (5
position), R ₃ is a methyl group (2nd position), X is a group -P
(OC ₁₃ H ₂₇ ) ₂ , m is a compound represented by 1, the medical device according to any one of Items 1 to 4 above. (7) The above-mentioned phenol phosphite compound is represented by the above formula [], and R ₂ is a t-butyl group (5
position), R ₃ is a methyl group (2nd position), X is a group -P
(OC ₁₃ H ₂₇ ) ₂ , Y is a group 〓CH-CH ₂ -CH ₂ -CH ₃
Items 1 to 4 above, which are compounds represented by
Medical devices listed in any of the following paragraphs. (8) The phenol compound is represented by formula []
R ₂ and R ₃ are t-butyl groups (3 and 5 positions), -OH
The medical device according to any one of the above items 1 to 4, which is a compound in which Z is a methylene group and Z is a methylene group. (9) The nucleating agent is R ₅ and
Items 1 to 8 above are compounds in which R ₆ is a methyl group (4th position), n ₁ and n ₂ are 1, and P is 1.
Medical devices listed in any of the following paragraphs. (10) The medical device according to any one of the above items 1 to 9, wherein the molded product is an injection molded product. (11) The medical device according to item 10 above, wherein the injection molded product is a syringe barrel, a needle base of an injection needle, an infusion or blood transfusion set, or a blood sampling device. (12) 0.01 to 0.4 parts by weight of a hindered amine represented by the following formula [] or [] as a stabilizer to 100 parts by weight of a propylene polymer having a ratio of weight average molecular weight to number average molecular weight of 5 or less, and the following formula [], Phenol or its phosphite compound represented by [] or []0.01~
A radiation sterilizable medical device, characterized in that it is a radiation sterilized molded article, comprising a composition containing 0.4 parts by weight and 0.01 to 0.4 parts by weight of a compound represented by the following formula [] as a nucleating agent. In the above formula, R ₁ is an alkyl group having 1 to 12 carbon atoms, R ₂ is an alkyl group having 3 to 12 carbon atoms, R ₃ is an alkyl group having 1 to 18 carbon atoms, and X is a hydrogen atom or a group.

[Formula] (R ₄ in the group represents an alkyl group having 1 to 30 carbon atoms), Y is a divalent hydrocarbon group having 1 to 18 carbon atoms or a sulfur atom, and Z has a carbonyloxy group embedded therein. _R5 and _R6 are alkyl or alkoxy groups, hydroxyl groups or halogen atoms having 1 to 8 carbon atoms, k is an integer of 1 to 10, l is m is an integer of 1 to 6, _n1 and _n2 are each independently an integer of 1 to 3, and p is 0 or 1. (13) The medical device according to item 12 above, wherein the radiation sterilization is γ-ray or X-ray sterilization. As described above, the medical device of the present invention has a ratio of weight average molecular weight to number average molecular weight (hereinafter referred to as Q value).
is 5 or less, to 100 parts by weight of a propylene polymer,
0.01 to 0.4 parts by weight of a hindered amine represented by the above formula [] or [] and 0.01 to 0.01 to 0.4 parts by weight of a phenol or its phosphite compound represented by the above formula [], [] or [] as a stabilizer.
This is a molded article made of a composition containing 0.4 parts by weight and 0.01 to 0.4 parts by weight of the compound represented by the above formula [] as a nucleating agent. In the present invention, the Q value is 5 or less, preferably
A 2.5-4.8 propylene polymer is used. The Q value indicates the molecular weight distribution, and the smaller the Q value, the narrower the molecular weight distribution. Propylene polymers with a Q value greater than 5 are unsuitable for use in the present invention because their impact strength is significantly reduced by radiation irradiation. The Q value is controlled by methods known per se. For example, selection of the catalyst used in the production of propylene polymer, selection of monomer feed method, polymerization conditions such as polymerization pressure and polymerization temperature, method of thermally decomposing the obtained powder when pelletizing, peroxide A propylene polymer having a desired Q value can be obtained by adding and decomposing the propylene polymer. In addition, the propylene polymer referred to in the present invention includes a polymer of propylene alone, that is, a propylene homopolymer, a propylene-ethylene copolymer having an ethylene content of 5% by weight or less, and a propylene homopolymer and a propylene-ethylene copolymer. Blends containing 5% by weight or less of ethylene are included. The copolymer may be either random or block, but a random copolymer is preferred. Propylene homopolymer has a high rigidity in molded products, so when manufacturing medical devices that require flexibility, it is recommended to copolymerize a small amount of ethylene to control the rigidity of the molded product, as described above. desirable. The appropriate melt flow index (MFR) of the polymer is approximately 5 to 50 g/10 min, depending on the type of product. For example, for the outer barrel of a syringe, it is desirable to have an ethylene content of 1.5 to 4.0 weight percent and an MFR of 10 to 30, and for the syringe needle hub and the octopus tube of the infusion set, it is desirable to have an ethylene content of 0 to 4.0 weight percent and an MFR of 6 to 30. is desirable. Suitable examples of hindered amines used as stabilizers include compounds in which R ₁ is a methyl group and k is 3 to 4 in the formula []; compounds in which R ₁ is a methyl group and l is 2 in the formula []; , etc. In the present invention, two or more hindered amines having the formula [] or [] can also be used in combination. These hindered amines are blended in an amount of 0.01 to 0.4, preferably 0.03 to 0.3 parts by weight, per 100 parts by weight of the propylene polymer. Another suitable example of a phenol or its phosphite compound, which is another stabilizer, is a formula [] in which R ₂ is a t-butyl group (5
position), R ₃ is a methyl group (2nd position), X is a hydrogen atom, m
is 1, R ₂ is a t-butyl group (5th position),
R ₃ is a methyl group (2nd position), X is a group -P
(OC ₁₃ H ₂₇ ) ₂ , a compound where m is 1, in the formula [], R ₂ is a t-butyl group (5th position), R ₃ is a methyl group (2nd position), X is a hydrogen atom, and Y is a group 〓CH−CH ₂₋
A compound in which R 2 is CH ₂ -CH ₃ , R ₂ is a t-butyl group (5
position), R ₃ is a methyl group (2nd position), X is a hydrogen atom, Y
is -S-, R ₂ is a t-butyl group (5
position), R ₃ is a methyl group (2nd position), X is a group -P
(OC ₁₃ H ₂₇ ) ₂ , a compound in which Y is a group 〓CH-CH ₂ -CH ₂ -CH ₃ , in the formula [], R ₂ and R ₃ are t-butyl groups (3 and 5 positions), and Z is Compounds in which R ₂ and R ₃ are methylene groups, t-butyl groups (3,5
position), and compounds where Z is a group -CH ₂ CH ₂ COOCH ₂ CH ₂ -. In the present invention, two or more types of phenols or phosphorous esters thereof having formulas [] to [] can also be used in combination. These phenols or their phosphite compounds are propylene polymers.
0.01-0.4 preferably 0.03-0.3 per 100 parts by weight
Parts by weight are added. Suitable examples of the nucleating agent used in the present invention include compounds in which R ₅ and R ₆ are methyl groups (4th position), n ₁ and n ₂ are 1, and p is 1 in the formula []. . Nucleating agent is propylene polymer
0.01-0.4 preferably 0.05-0.3 per 100 parts by weight
Parts by weight are added. The thus obtained composition of the present invention may contain other additives, such as antioxidants, nucleating agents, light stabilizers, ultraviolet absorbers, antistatic agents, and metal soaps, to the extent that the objects and effects of the present invention are not impaired. Neutralizing agents, dispersants, pigments, etc. can be added. The medical device of the present invention comprises rolling the above composition;
The mixture is melt-kneaded using a kneading machine such as a Banbury mixer, Brabender Plastograph, or an extruder, and then molded into a medical device using injection molding or the like. Generally, each additive is blended into a powdered propylene polymer, mixed in a suitable mixing device such as a mixer, and then melted and kneaded in an extruder to form pellets, or directly injection molded without pelletizing. do. It is preferable that the injection molded product be packaged with a polyester polyethylene laminate film or the like and sterilized by radiation before being shipped as is. γ-rays or X-rays are used as radiation, preferably γ-rays from a cobalt-60 source.
A line is used. The irradiation amount is 5 megarads or less, preferably 2 to 4 megarads, and excessive irradiation causes deterioration of the molded product. Irradiation may be performed in vacuum, in an inert gas such as nitrogen, or in air, and is carried out at a temperature of 80° C. or lower, preferably room temperature or lower. Examples of radiation sterilizable medical instruments obtained by the present invention include, but are not limited to, syringe barrels, syringe needles, bases of syringe needles, infusions, blood transfusion sets, and blood sampling instruments. do not have. Next, the present invention will be explained in more detail with reference to Examples and Comparative Test Examples. Example 1 The hindered amine, phenol or its phosphite compound of the present invention, and a nucleating agent were added to a powdered propylene-ethylene random copolymer in the amounts shown in Table 1, and the mixture was heated in a 30 mm diameter extruder (230°C ) and pelletized. At that time, pellets
In order to adjust the MFR (230℃, 2.16Kg) and Q value to the values listed in Table 1, we selected the MFR of the base powder and perhexine 25B [2,5-dimethyl-
2,5-di(t-butylperoxy)hexyne-
3 (trade name)] was added to obtain prescribed pellets. The obtained pellets were put through an injection molding machine IS90B made by Toshiba Machine, and a square sheet of 100 x 100 x 1 mm was formed (280°C), and the sheet was irradiated with gamma rays (2.5 megarads) using a cobalt 60 radiation source and used for evaluation. did. Evaluation items included visually determining the degree of coloration after placing the specimen in an 80℃ oven for one week, measuring haze using a haze meter (ASTM-D-1003), and using a Dupont impact tester manufactured by Toyo Seiki. Measurement of energy at 50% failure of specimen, number of days until cracking or embrittlement when specimen is placed in 120℃ oven, MFR measurement of specimen and 80℃
After the test piece was placed in an oven for one week, the state of bleeding on the surface was observed. For cytotoxicity tests, add 3 times the volume of the strip sample to
Extraction was performed with MEM medium at 121°C for 20 minutes, and the toxicity of the extract to HeLa-S3 cells was determined using a microscope. 0 if there is no difference from the blank, 1 if there is a slight increase in dead cells, 2 if all but a few cells are dead, 3 if all cells are dead.
was displayed. For hemolytic toxicity, a specimen with a surface area ^of 1200 cm2 was tested.
Rabbit washed red blood cells were added to the extracted solution obtained by immersion in physiological saline at 121°C for 20 minutes, and after being left at 37°C for 24 hours, the degree of coloration of the solution was evaluated. No difference from the blank (-), pale red coloring (low toxicity) (±), red coloring (+), dark red coloring (high toxicity) was displayed. The results are shown in Table 1.

【table】

[Table] In the table, the stabilizer, nucleating agent, and auxiliary agent listed by product name represent the following compounds, respectively. Sanol LS622 Ciba Geigy product A compound in which R ₁ = CH ₃ and k = 3 to 4 in the formula []. Mark LA57 A product of Adeka Argus Chemical Co., Ltd. Sanol, a compound in which R ₁ = CH ₃ , l = 2 in the formula [] LS770 A product of Sankyo Co., Ltd. Chemical name: bis(2,2,6,6-tetramethylpiperidyl) sebacate topanol CA ICI product Compound of formula [] 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butanegutudolite 3114 Gutudritsch Chemical Co. product Compound of formula [] Tris(3,5 -di-tert-butyl-4-hydroxybenzyl) isocyanurate mark 522A Adeka Argus Chemical Co., Ltd. product In the formula [], R ₂ = t-butyl group, R ₃ =
Methyl group (2nd position),

[Formula] Compound DMTP where m = 1 Yoshitomi Pharmaceutical product Dimyristyl thiodipropionate gelol MD Shinnihon Chemical Co., Ltd. product Compound [Formula] where R ₅ and R ₆ are methyl groups (p) and n is 1 ( 1,3,2,4-
Di-(p-methylbenzylidene)-sorbitol EC1 Product from EC Chemical Co., Ltd. 1,3,2,4-dibenzylidene-sorbitol PBK Product from Nitto Chemical Co., Ltd. Calcium stearate In Table 1, Examples 1-(1) to (5) 1 and 2 respectively show the compositions of the present invention in which the stabilizer and nucleating agent of the present invention are blended with a propylene polymer, that is, the compositions of the present invention. Comparative Example 1-(1) shows an example in which only the hindered amine of the present invention was blended as a stabilizer, and phenol or its phosphite and the nucleating agent of the present invention were not blended. ) shows an example in which a hindered amine other than the one of the present invention was blended as a stabilizer. Comparative Examples 1-(3) to (5) are examples in which the phenol compound or phosphoric acid ester of the present invention was blended with a propylene polymer having a Q value of 5 or more, but the hindered amine of the present invention was not blended. show. From the results in Table 1, it can be seen that the impact strength of the injection molded device of the present invention does not decrease significantly by γ-ray irradiation, whereas the comparative example shows a significant decrease in impact strength. Further, while the molded product of the present invention is not colored at all, the molded product of the comparative example is colored yellow. Furthermore, it has been shown to be excellent in terms of toxicity and suppressive effect on molecular weight reduction. Example 2 Pellets having the compositions shown in Table 2 were prepared in the same manner as in Example 1. However, an extruder with a diameter of 50 mm (230°C) was used. The obtained pellets were applied to a Nestal 350T injection molding machine manufactured by Sumitomo Heavy Industries, Ltd. to form a syringe outer cylinder having an internal capacity of 10 ml (at 280°C), and irradiated with gamma rays in the same manner as in Example 1. In addition to the evaluation items listed in Table 1 of Example 1, transparency was determined visually. For the compression test, the syringe outer cylinder was placed in an oven at 80°C and heat treated for a specified number of days, and then using an autograph tester, a round bar with a radius of 5 mm was pressed against the center of the syringe outer cylinder at a speed of 50 mm/min to determine the syringe diameter. (outer diameter 17 mm) was deformed until it was reduced by about half, and cracks were observed. If even one of the three samples was cracked, it was determined to be a crack. Regarding odor, the syringe outer barrel was placed in a 20μ polyester film, sealed, and then irradiated with gamma rays. Thirty days after irradiation, the package was opened and a sensory test using the human sense of smell was conducted to determine the presence or absence of odor. Furthermore, as a method for evaluating the surface condition of the syringe, 30 days after γ-ray irradiation, the contact angle between the syringe surface and the silicone droplet was measured (polydimethylsiloxane, 3000cst), and this was used as a guide for bleeding of decomposed products to the surface. The results are shown in Table 2.

[Table] In Table 2, Examples 2-(1) and (2) show compositions in which the stabilizer and nucleating agent of the present invention are blended with propylene-ethylene random copolymer (Q value 5 or less). These are test examples for molded articles, ie, molded articles of the present invention, and Comparative Examples 2-(1) to (5) show test examples in which a nucleating agent other than the present invention was blended. From the results in Table 2, the molded products of the present invention are excellent in all evaluation items including degree of coloration, transparency, compressive strength, oven life, bleedability, odor, contact angle of silicone droplets, and toxicity. This shows that it can be put to practical use as a radiation-resistant medical device. Changes in the contact angle of the silicone droplets in the above test indicate bleed of the additive onto the molded article surface. In Example 2-(2), the contact angle did not increase significantly before and after radiation irradiation, but in Comparative Example 2-
In (1), there is a large increase. This is EC-1
The results show that hydrophilic substances bled onto the surface and repelled the silicone. Example 3 Pellets made by melting and kneading powders having the respective compositions shown in Table 3 were molded into pellets with an outer diameter of 17.7 mm using an injection molding machine.
The outer barrel of the syringe was molded into a syringe barrel having a cylindrical portion with a length of 750 mm and a wall thickness of 0.98 mm. The samples were wrapped in 20μ polyethylene terephthalate packaging and irradiated with 2.5 megarads using a cobalt-60 source. The samples were placed in an 80℃ air circulation oven for 7 days.
A group left for 1 day, a group left at room temperature for 30 days after irradiation,
After irradiation, the samples were left in an air circulation oven at 80° C. for 7 days, and the samples were divided into four groups, and measurements were performed according to the following method. The hue was determined visually, and no coloring was indicated by ◎, very slight yellowing by ○, slight yellowing by △, and yellowing by ×. Regarding potassium permanganate reducing substances,
A sample cut into 1 square centimeter pieces was extracted with 10 times the volume of distilled water at 121°C for 20 minutes, and measured according to the disposable syringe standard section and expressed as ΔKMnO ₄ . Bleeding was determined visually. A sample with no bleed was indicated as -, and a sample with bleed was indicated as +. The compressive strength was determined by compressing the center of the syringe with a 7 mm steel round bar and measuring the load at which the syringe broke. Measurements were performed at 25°C. In the table, the symbol - indicates no breakage. The impact strength was determined by dropping a cylinder weighing 120 g and having a diameter of 30 mm at different heights, and determining the 50% fracture energy in accordance with JIS-K7211. Measurements were performed at 25°C. The time required for cracks to occur after irradiation was determined using a gear oven at 120°C, and the presence or absence of cracks was determined visually. Regarding odor, when the package was opened, odorless products were rated as ◎, products that had a slight odor as ○, products that had a strong odor as △, and products that had an unpleasant odor as ×. Regarding transparency, it is about the one molded into a 1mm thick sheet.
Haze was measured according to ASTM (D-1003).
Cytotoxicity and hemolytic toxicity were tested using the same test method as in Example 1. The results are shown in Table 3.

【table】

[Table] In Table 3, Example 3-(1) to (3) has a Q value of 4.4.
This is a test example of a molded article of a composition in which the stabilizer and nucleating agent of the present invention are blended with the propylene polymer of the present invention, that is, the molded article of the present invention. , is an example in which the stabilizer according to the present invention and a nucleating agent other than the present invention were blended into a propylene polymer with a Q value of 4.4, and Comparative Examples 3-(1) and (3) are examples in which the stabilizer according to the present invention was blended However, this is an example in which no nucleating agent was added.
From the results in Table 3, the molded product of the present invention showed good results in all evaluation items, especially the elution of potassium permanganate reducing substances (ΔKMnO ₄ value).
The results show that the nucleating agent of the present invention is significantly superior to the control in terms of odor generation and odor generation. Effects of the Invention According to the present invention, a propylene polymer medical device that can be commercially subjected to radiation sterilization is provided. That is, according to the present invention, firstly, a medical instrument is provided in which the strength and transparency of the material are less reduced by radiation irradiation. Propylene polymer material deteriorates significantly when irradiated with radiation, but as shown above, molded products to which the stabilizer and nucleating agent of the present invention have been added have minimal decline in impact strength, compressive strength, etc. It maintains its transparency and is fully usable as a medical device. According to the present invention, secondly, a medical instrument is provided that does not show coloration due to radiation irradiation. Some of the conventionally known stabilizers decompose and color the product when exposed to radiation, and such stabilizers cannot be used in medical devices even if they have excellent anti-deterioration effects. Can not do it. Thirdly, according to the present invention, a safe medical device is provided without bleeding of additives or elution of toxic decomposition products. Some conventional stabilizers bleed onto the product surface over time or decompose due to radiation irradiation to produce toxic substances, which are then leached into the contents that come into contact with the medical device. However, as shown above, such a phenomenon is not observed in the stabilizer used in the present invention. Fourthly, according to the present invention, a medical instrument is provided that does not generate odor due to radiation irradiation. A nucleating agent is blended into propylene polymer products as a clarifying agent, but some of the nucleating agents conventionally used decompose when irradiated with radiation and emit an unpleasant odor. The nucleating agent used in the present invention does not generate any unpleasant odor. In this way, the present invention creates a practical radiation sterilizable medical device by skillfully selecting and blending a specific stabilizer and nucleating agent with a propylene polymer having a specific molecular weight distribution, and then molding the propylene polymer. This is what we provide.

Claims (1)

[Claims] 1. 0.01 to 0.4 parts by weight of a hindered amine represented by the following formula [] or [] as a radiation stabilizer to 100 parts by weight of a propylene polymer having a ratio of weight average molecular weight to number average molecular weight of 5 or less and Phenol or its phosphite compound represented by the following formula [], [] or []0.01-0.4
1. A medical device characterized in that it is a molded article comprising a composition containing 0.01 to 0.4 parts by weight of a compound represented by the following formula [] as a nucleating agent. In the above formula, R ₁ is an alkyl group having 1 to 12 carbon atoms, R ₂ is an alkyl group having 3 to 12 carbon atoms, R ₃ is an alkyl group having 1 to 18 carbon atoms, and X is a hydrogen atom or a group [ [Formula] (R ₄ in the group represents an alkyl group having 1 to 30 carbon atoms), Y is a divalent hydrocarbon group having 1 to 18 carbon atoms or a sulfur atom, and Z is a carbonyloxy group containing an internal carbonyloxy group. a divalent hydrocarbon group having 1 to 8 carbon atoms, R ₅ and R ₆ are alkyl or alkoxy groups having 1 to 8 carbon atoms, a hydroxyl group or a halogen atom, k is an integer of 1 to 10, l is 1 ~16 integer, m is an integer from 1 to 6, _m1 and _n2 are each independently an integer from 1 to 3,
and p represents 0 or 1, respectively. 2 The ratio of weight average molecular weight to number average molecular weight is 2.5~
4.8, 0.03 to 0.3 parts by weight of a hindered amine represented by the above formula [] or [] as a radiation stabilizer, and a phenol or its substituent represented by the above formula [], [] or []. Phosphate ester compound 0.02~
The medical device according to claim 1, which is a molded article comprising a composition containing 0.2 parts by weight and 0.05 to 0.3 parts by weight of the compound represented by the formula [] as a nucleating agent. 3. The medical device according to claim 1 or 2, wherein the hindered amine is a compound in which R ₁ is a methyl group and k is 3 or 4 in the formula []. 4. The medical device according to claim 1 or 2, wherein the hindered amine is a compound in which R ₁ is a methyl group and l is 2 in the formula []. 5 The phenol compound has the above formula [], R ₂ is a t-butyl group, R ₃ is a methyl group (2nd position),
The medical device according to any one of claims 1 to 4, wherein X is a hydrogen atom and m is a compound represented by 1. 6 The phenol phosphite compound has the above formula [], and R ₂ is a t-butyl group (5
position), R ₃ is a methyl group (2nd position), X is a group -P
(OC ₁₃ H ₂₇ ) ₂ , m is a compound represented by 1, the medical device according to any one of claims 1 to 4. 7 The phenol phosphite compound has the above formula [], and R ₂ is a t-butyl group (5
position), R ₃ is a methyl group (2nd position), X is a group -P
(OC ₁₃ H ₂₇ ) ₂ , Y is a compound represented by the group 〓CH-CH ₂ -CH ₂ -CH ₃ , the medical device according to any one of claims 1 to 4 . 8 The phenol compound is represented by the formula []
According to any one of claims 1 to 4, wherein R ₂ and R ₃ are t-butyl groups (3 and 5 positions), -OH is a 4-position, and Z is a methylene group. Medical equipment as described. 9 The nucleating agent is R ₅ and
R ₆ is a methyl group (4th position), n ₁ and n ₂ are 1, and p is 1
The medical device according to any one of claims 1 to 8, which is a compound represented by: 10. The medical device according to any one of claims 1 to 9, wherein the molded product is an injection molded product. 11 The injection molded product is a syringe barrel, a needle base of a syringe needle,
11. The medical device according to claim 10, which is an infusion or blood transfusion set or a blood collection device. 12. The medical device according to any one of claims 1 to 11, wherein the molded product is radiation sterilized.