Polypropylene resin composition, and molded article for medical use

Abstract

Disclosed is a polypropylene resin composition which contains a propylene-based polymer, an elastomer, and an NH-type hindered amine compound that has a triazine ring. The elastomer content is 1% by mass to 20% by mass inclusive based on the total amount of the propylene-based polymer and the elastomer. The content of the NH-type hindered amine compound is 100 ppm by mass to 20,000 ppm by mass inclusive based on the total amount of the propylene-based polymer and the elastomer.

Description

Polypropylene resin composition and medical molded article

[0001] The present disclosure relates to a polypropylene resin composition and a medical molded article.

[0002] Polypropylene resin compositions are sometimes used to form medical molded articles such as syringe barrels or dialyzer housings (see, for example, Patent Document 1).

[0003] JP 2019-31609 A International Publication No. 2016 / 200335

[0004] The present disclosure relates to a polypropylene resin composition that can form a molded article with little elution after sterilization with gamma rays.

[0005] The present disclosure includes the following: [1] A polypropylene resin composition comprising a propylene-based polymer, an elastomer, and an NH-type hindered amine compound having a triazine ring, wherein the content of the elastomer is 1% by mass or more and 20% by mass or less based on the total amount of the propylene-based polymer and the elastomer, and the content of the NH-type hindered amine compound is 100 ppm by mass or more and 20,000 ppm by mass or less based on the total amount of the propylene-based polymer and the elastomer. [2] The polypropylene resin composition according to [1], wherein the propylene-based polymer is a copolymer containing ethylene-derived monomer units in a proportion of 0.1% by mass or more and 7.0% by mass or less based on the mass of the propylene-based polymer. [3] The polypropylene resin composition according to [1] or [2], wherein the elastomer comprises a styrene-based elastomer, an ethylene-based elastomer, or a combination thereof. [4] The polypropylene resin composition according to any one of [1] to [3], wherein the NH-type hindered amine compound has a number average molecular weight of 2,000 or more. [5] The polypropylene resin composition according to any one of [1] to [4], comprising two or more of the propylene polymers having different melting points. [6] A medical molded article comprising the polypropylene resin composition according to any one of [1] to [5]. [7] A syringe comprising an outer cylinder having the medical molded article according to [6]. [8] A dialyzer comprising a housing having the medical molded article according to [6].

[0006] A polypropylene resin composition can be provided that can form a molded article with little elution after sterilization with gamma rays.

[0007] 1 is a plan view showing an example of a syringe;

[0008] The present invention is not limited to the following examples.

[0009] An example of a polypropylene resin composition includes a propylene polymer, an elastomer, and an NH-type hindered amine compound having a triazine ring, and can be used as a molding material for forming molded articles such as medical molded articles.

[0010] A propylene-based polymer is a polymer mainly composed of monomer units derived from propylene. The propylene-based polymer may be a homopolymer of propylene or a copolymer of propylene and another copolymerizable monomer. The propylene-based polymer may be crystalline.

[0011] From the viewpoint of mechanical properties of a molded article, the content of propylene-derived monomer units in the propylene polymer may be 85% by mass or more, 90% by mass or more, 93% by mass or more, 94% by mass or more, or 95% by mass or more, based on the mass of the propylene polymer. The content of propylene-derived monomer units may be 100% by mass or less, 99.9% by mass or less, or 98% by mass or less, based on the mass of the propylene polymer. The content of propylene-derived monomer units in the propylene polymer may be 85% by mass or more, 90% by mass or more, 93% by mass or more, 94% by mass or more, or 95% by mass or more, and 100% by mass or less, based on the mass of the propylene polymer. The content of the propylene-derived monomer units in the propylene polymer may be 85% by mass or more, 90% by mass or more, 93% by mass or more, 94% by mass or more, or 95% by mass or more and 99.9% by mass or less, based on the mass of the propylene polymer. The content of the propylene-derived monomer units in the propylene polymer may be 85% by mass or more, 90% by mass or more, 93% by mass or more, 94% by mass or more, or 95% by mass or more and 98% by mass or less, based on the mass of the propylene polymer.

[0012] The copolymerizable monomer constituting the propylene-based polymer may be, for example, ethylene or an α-olefin, and the α-olefin may be an α-olefin having 4 to 20 carbon atoms. The copolymerizable monomer may be any combination selected from ethylene and α-olefins.

[0013] Examples of the α-olefin having 4 to 20 carbon atoms include butene-1, pentene-1, hexene-1, 4-methylpentene-1, heptene-1, octene-1, and decene-1. The propylene-based polymer may be a copolymer of propylene and one or more copolymerizable monomers selected from ethylene, butene-1, pentene-1, hexene-1, 4-methylpentene-1, heptene-1, octene-1, and decene-1, and examples thereof include a propylene-ethylene copolymer, a propylene-butene-1 copolymer, a propylene-ethylene-butene-1 copolymer, a propylene-hexene-1 copolymer, and a propylene-ethylene-hexene-1 copolymer. The propylene-based polymer may be at least one selected from a propylene-ethylene copolymer, a propylene-butene-1 copolymer, and a propylene-ethylene-butene-1 copolymer.

[0014] The content of monomer units derived from a copolymerizable monomer (e.g., ethylene) in the propylene polymer may be 0% by mass or more, 0.1% by mass or more, or 2.0% by mass or more, and may be 15% by mass or less, 10% by mass or less, 7.0% by mass or less, 6.0% by mass or less, or 5.0% by mass or less, based on the mass of the propylene polymer. The content of monomer units derived from a copolymerizable monomer (e.g., ethylene) in the propylene polymer may be 0% by mass or more, 0.1% by mass or more, or 2.0% by mass or more and 15% by mass or less, based on the mass of the propylene polymer. The content of monomer units derived from a copolymerizable monomer (e.g., ethylene) in the propylene polymer may be 0% by mass or more, 0.1% by mass or more, or 2.0% by mass or more and 10% by mass or less, based on the mass of the propylene polymer. The content of monomer units derived from a copolymerizable monomer (e.g., ethylene) in the propylene polymer may be 0% by mass or more, 0.1% by mass or more, or 2.0% by mass or more and 7.0% by mass or less, based on the mass of the propylene polymer. The content of monomer units derived from a copolymerizable monomer (e.g., ethylene) in the propylene polymer may be 0% by mass or more, 0.1% by mass or more, or 2.0% by mass or more and 6.0% by mass or less, based on the mass of the propylene polymer. The content of monomer units derived from a copolymerizable monomer (e.g., ethylene) in the propylene polymer may be 0% by mass or more, 0.1% by mass or more, or 2.0% by mass or more and 5.0% by mass or less, based on the mass of the propylene polymer.

[0015] The melt flow rate (MFR) of the propylene polymer at a temperature of 230°C and a load of 21.18 N may be 0.1 g / 10 min or more, 1.0 g / 10 min or more, 2.0 g / 10 min or more, 3.0 g / 10 min or more, 4.0 g / 10 min or more, or 5.0 g / 10 min or more, and may be 100 g / 10 min or less, 50 g / 10 min or less, 40 g / 10 min or less, or 30 g / 10 min or less. The melt flow rate (MFR) of the propylene polymer at a temperature of 230°C and a load of 21.18 N may be 0.1 g / 10 min or more, 1.0 g / 10 min or more, 2.0 g / 10 min or more, 3.0 g / 10 min or more, 4.0 g / 10 min or more, or 5.0 g / 10 min or more, and 100 g / 10 min or less. The propylene polymer may have a melt flow rate (MFR) of 0.1 g / 10 min or more, 1.0 g / 10 min or more, 2.0 g / 10 min or more, 3.0 g / 10 min or more, 4.0 g / 10 min or more, or 5.0 g / 10 min or more and 50 g / 10 min or less at a temperature of 230°C and a load of 21.18 N. The propylene polymer may have a melt flow rate (MFR) of 0.1 g / 10 min or more, 1.0 g / 10 min or more, 2.0 g / 10 min or more, 3.0 g / 10 min or more, 4.0 g / 10 min or more, or 5.0 g / 10 min or more and 40 g / 10 min or less at a temperature of 230°C and a load of 21.18 N. The propylene polymer may have a melt flow rate (MFR) of 0.1 g / 10 min or more, 1.0 g / 10 min or more, 2.0 g / 10 min or more, 3.0 g / 10 min or more, 4.0 g / 10 min or more, or 5.0 g / 10 min or more and 30 g / 10 min or less at a temperature of 230°C and a load of 21.18 N. When the propylene polymer has an appropriate melt flow rate, good fluidity is easily obtained when the resin composition is extrusion molded or injection molded.

[0016] The polypropylene resin composition may contain two or more propylene polymers having different melting points. For example, the polypropylene resin composition may contain a propylene polymer having a melting point of 160°C or higher and a propylene polymer having a melting point lower than 160°C. The difference in melting points of the two or more propylene polymers may be 5°C or higher. The melting points of the propylene polymers herein are values ​​measured by differential scanning calorimetry.

[0017] The elastomer contained in the polypropylene resin composition may be a styrene-based elastomer, an ethylene-based elastomer, or both. The polypropylene resin composition may form a phase-separated structure composed of a continuous phase mainly containing a propylene-based polymer and particles (elastomer particles) mainly containing an elastomer dispersed in the continuous phase.

[0018] A styrene-based elastomer is an elastomer containing styrene as a monomer unit. The proportion of the styrene-derived monomer units in the styrene-based elastomer may be 5% by mass or more, or 10% by mass or more, and may be 60% by mass or less, 50% by mass or less, or 40% by mass or less, based on the total mass of the styrene-based elastomer. The proportion of the styrene-derived monomer units in the styrene-based elastomer may be 5% by mass or more, or 10% by mass or more and 60% by mass or less, based on the total mass of the styrene-based elastomer. The proportion of the styrene-derived monomer units in the styrene-based elastomer may be 5% by mass or more, or 10% by mass or more and 50% by mass or less, based on the total mass of the styrene-based elastomer. The proportion of the styrene-derived monomer units in the styrene-based elastomer may be 5% by mass or more, or 10% by mass or more and 40% by mass or less, based on the total mass of the styrene-based elastomer. The styrene-based elastomer may be a hydrogenated product in which some or all of the unsaturated bonds derived from the alkadiene monomer (usually excluding the unsaturated bonds in the benzene ring derived from styrene) have been converted to saturated bonds by hydrogenation. Hydrogenation tends to improve heat resistance.

[0019] The styrene-based elastomer may be, for example, a block copolymer composed of a polystyrene block and a polyolefin block consisting of monomer units derived from an alkadiene having 4 to 10 carbon atoms, or a hydrogenated product thereof. From the viewpoints of compatibility with the propylene-based polymer and impact resistance, the polyolefin block may contain at least one alkadiene of isoprene or butadiene as a monomer unit. In this specification, elastomers containing styrene and ethylene as monomer units are classified as styrene-based elastomers.

[0020] The styrene elastomer may be a diblock copolymer consisting of a polystyrene block bonded to a polyolefin block, or a triblock copolymer consisting of polystyrene blocks at both ends and a polyolefin block sandwiched between them, which can contribute to improving the impact resistance of the molded article.

[0021] Examples of styrene-based elastomers include hydrogenated styrene-butadiene-styrene block copolymers, hydrogenated styrene-isoprene-styrene block copolymers, and hydrogenated styrene-isoprene-butadiene-styrene block copolymers.

[0022] Examples of commercially available styrene-based elastomers include Kraton (trade name) manufactured by Kraton Polymers, Tuftec (trade name) manufactured by Asahi Kasei Corporation, Septon and Hybler (trade names) manufactured by Kuraray, and Dynalon (trade name) manufactured by JSR Corporation.

[0023] Ethylene-based elastomers are copolymers containing ethylene and α-olefins as monomer units. Examples of α-olefins constituting ethylene-based elastomers include propylene, butene-1, pentene-1, hexene-1, heptene-1, and octene-1. Examples of ethylene-based elastomers include ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer, and ethylene-octene-1 copolymer.

[0024] Examples of commercially available ethylene-based elastomers include "Excellen" and "Esprene" manufactured by Sumitomo Chemical Co., Ltd., and "Evolue" and "Tafmer" manufactured by Mitsui Chemicals, Inc.

[0025] The elastomer may have a melt flow rate (MFR) at a temperature of 190°C and a load of 21.18 N of 0.1 g / 10 min or more, 0.3 g / 10 min or more, 1 g / 10 min or more, 3 g / 10 min or more, or 5 g / 10 min or more, or may have a melt flow rate (MFR) of 50 g / 10 min or less, 40 g / 10 min or less, 30 g / 10 min or less, 20 g / 10 min or less, or 15 g / 10 min or less. The elastomer may have a melt flow rate (MFR) at a temperature of 190°C and a load of 21.18 N of 0.1 g / 10 min or more, 0.3 g / 10 min or more, 1 g / 10 min or more, 3 g / 10 min or more, or 5 g / 10 min or more, and 50 g / 10 min or less. The elastomer may have a melt flow rate (MFR) of 0.1 g / 10 min or more, 0.3 g / 10 min or more, 1 g / 10 min or more, 3 g / 10 min or more, or 5 g / 10 min or more and 40 g / 10 min or less at a temperature of 190°C and a load of 21.18 N. The elastomer may have a melt flow rate (MFR) of 0.1 g / 10 min or more, 0.3 g / 10 min or more, 1 g / 10 min or more, 3 g / 10 min or more, or 5 g / 10 min or more and 30 g / 10 min or less at a temperature of 190°C and a load of 21.18 N. The elastomer may have a melt flow rate (MFR) at a temperature of 190°C and a load of 21.18 N of 0.1 g / 10 min or more, 0.3 g / 10 min or more, 1 g / 10 min or more, 3 g / 10 min or more, or 5 g / 10 min or more and 20 g / 10 min or less. The elastomer may have a melt flow rate (MFR) at a temperature of 190°C and a load of 21.18 N of 0.1 g / 10 min or more, 0.3 g / 10 min or more, 1 g / 10 min or more, 3 g / 10 min or more, or 5 g / 10 min or more and 15 g / 10 min or less. If the MFR of the elastomer is high, the impact resistance improving effect tends to decrease. If the MFR is too low, the dispersibility of the elastomer in the resin composition decreases, so the dispersed particle size of the elastomer particles tends to increase and the transparency of the molded product tends to decrease.

[0026] The content of the elastomer in the polypropylene resin composition is 1% by mass or more and 20% by mass or less, based on the total amount of the propylene-based polymer and the elastomer. The content of the elastomer may be 2% by mass or more, 3% by mass or more, or 4% by mass or more, based on the total amount of the propylene-based polymer and the elastomer, and may be 15% by mass or less, or 10% by mass or less. When the content of the elastomer is within these ranges, color change and elution after sterilization by gamma rays can be particularly significantly suppressed. Here, "elastomer content" means the total amount of the styrene-based elastomer and the ethylene-based elastomer.

[0027] The total amount of the propylene-based polymer and the elastomer in the polypropylene resin composition may be 80% by mass or more, 85% by mass or more, 90% by mass or more, 95% by mass or more, 96% by mass or more, 97% by mass or more, 98% by mass or more, or 99% by mass or more, based on the mass of the polypropylene resin composition.

[0028] The NH-type hindered amine compound is a compound having a secondary amino group, which is a hindered amino group, and a triazine ring. The content of the NH-type hindered amine compound in the polypropylene resin composition is 100 ppm by mass or more and 20,000 ppm by mass or less based on the total amount of the propylene-based polymer and the elastomer. The content of the NH-type hindered amine compound may be 200 ppm by mass or more, 300 ppm by mass or more, 400 ppm by mass or more, 500 ppm by mass or more, 600 ppm by mass or more, 700 ppm by mass or more, 800 ppm by mass or more, 900 ppm by mass or more, or 1000 ppm by mass or more, based on the total amount of the propylene-based polymer and the elastomer, and may be 10000 ppm by mass or less, 9000 ppm by mass or less, 8000 ppm by mass or less, 7000 ppm by mass or less, 6000 ppm by mass or less, 5000 ppm by mass or less, 4000 ppm by mass or less, 3000 ppm by mass or less, 2500 ppm by mass or less, or 2000 ppm by mass or less. The NH-hindered amine compound content may be 200 ppm by mass or more, 300 ppm by mass or more, 400 ppm by mass or more, 500 ppm by mass or more, 600 ppm by mass or more, 700 ppm by mass or more, 800 ppm by mass or more, 900 ppm by mass or more, or 1000 ppm by mass or more and 20000 ppm by mass or less, based on the total amount of the propylene-based polymer and the elastomer. The NH-hindered amine compound content may be 100 ppm by mass or more, 200 ppm by mass or more, 300 ppm by mass or more, 400 ppm by mass or more, 500 ppm by mass or more, 600 ppm by mass or more, 700 ppm by mass or more, 800 ppm by mass or more, 900 ppm by mass or more, or 1000 ppm by mass or more and 10000 ppm by mass or less, based on the total amount of the propylene-based polymer and the elastomer. The content of the NH-type hindered amine compound may be 100 ppm by mass or more, 200 ppm by mass or more, 300 ppm by mass or more, 400 ppm by mass or more, 500 ppm by mass or more, 600 ppm by mass or more, 700 ppm by mass or more, 800 ppm by mass or more, 900 ppm by mass or more, or 1000 ppm by mass or more and 9000 ppm by mass or less, based on the total amount of the propylene-based polymer and the elastomer.The content of the NH-type hindered amine compound may be 100 ppm by mass or more, 200 ppm by mass or more, 300 ppm by mass or more, 400 ppm by mass or more, 500 ppm by mass or more, 600 ppm by mass or more, 700 ppm by mass or more, 800 ppm by mass or more, 900 ppm by mass or more, or 1000 ppm by mass or more and 8000 ppm by mass or less, based on the total amount of the propylene-based polymer and the elastomer. The content of the NH-type hindered amine compound may be 100 ppm by mass or more, 200 ppm by mass or more, 300 ppm by mass or more, 400 ppm by mass or more, 500 ppm by mass or more, 600 ppm by mass or more, 700 ppm by mass or more, 800 ppm by mass or more, 900 ppm by mass or more, or 1000 ppm by mass or more and 7000 ppm by mass or less, based on the total amount of the propylene-based polymer and the elastomer. The content of the NH-type hindered amine compound may be 100 ppm by mass or more, 200 ppm by mass or more, 300 ppm by mass or more, 400 ppm by mass or more, 500 ppm by mass or more, 600 ppm by mass or more, 700 ppm by mass or more, 800 ppm by mass or more, 900 ppm by mass or more, or 1000 ppm by mass or more and 6000 ppm by mass or less, based on the total amount of the propylene-based polymer and the elastomer. The content of the NH-type hindered amine compound may be 100 ppm by mass or more, 200 ppm by mass or more, 300 ppm by mass or more, 400 ppm by mass or more, 500 ppm by mass or more, 600 ppm by mass or more, 700 ppm by mass or more, 800 ppm by mass or more, 900 ppm by mass or more, or 1000 ppm by mass or more and 5000 ppm by mass or less, based on the total amount of the propylene-based polymer and the elastomer. The content of the NH-type hindered amine compound may be 100 ppm by mass or more, 200 ppm by mass or more, 300 ppm by mass or more, 400 ppm by mass or more, 500 ppm by mass or more, 600 ppm by mass or more, 700 ppm by mass or more, 800 ppm by mass or more, 900 ppm by mass or more, or 1000 ppm by mass or more and 4000 ppm by mass or less, based on the total amount of the propylene-based polymer and the elastomer.The content of the NH-type hindered amine compound may be 100 ppm by mass or more, 200 ppm by mass or more, 300 ppm by mass or more, 400 ppm by mass or more, 500 ppm by mass or more, 600 ppm by mass or more, 700 ppm by mass or more, 800 ppm by mass or more, 900 ppm by mass or more, or 1000 ppm by mass or more and 3000 ppm by mass or less, based on the total amount of the propylene-based polymer and the elastomer. The content of the NH-type hindered amine compound may be 100 ppm by mass or more, 200 ppm by mass or more, 300 ppm by mass or more, 400 ppm by mass or more, 500 ppm by mass or more, 600 ppm by mass or more, 700 ppm by mass or more, 800 ppm by mass or more, 900 ppm by mass or more, or 1000 ppm by mass or more and 2500 ppm by mass or less, based on the total amount of the propylene-based polymer and the elastomer. The content of the NH-type hindered amine compound may be 100 ppm by mass or more, 200 ppm by mass or more, 300 ppm by mass or more, 400 ppm by mass or more, 500 ppm by mass or more, 600 ppm by mass or more, 700 ppm by mass or more, 800 ppm by mass or more, 900 ppm by mass or more, or 1000 ppm by mass or more and 2000 ppm by mass or less, based on the total amount of the propylene-based polymer and the elastomer.

[0029] The number average molecular weight (Mn) of the NH-type hindered amine compound may be 2,000 or more, or 2,500 or more, or may be 20,000 or less, 15,000 or less, 10,000 or less, 9,000 or less, 8,000 or less, 7,000 or less, 6,000 or less, or 5,000 or less. The number average molecular weight (Mn) of the NH-type hindered amine compound may be 2,000 or more, or 2,500 or more and 20,000 or less. The number average molecular weight (Mn) of the NH-type hindered amine compound may be 2,000 or more, or 2,500 or more and 15,000 or less. The number average molecular weight (Mn) of the NH-type hindered amine compound may be 2,000 or more, or 2,500 or more and 10,000 or less. The number average molecular weight (Mn) of the NH hindered amine compound may be 2,000 or more, or 2,500 or more and 9,000 or less. The number average molecular weight (Mn) of the NH hindered amine compound may be 2,000 or more, or 2,500 or more and 8,000 or less. The number average molecular weight (Mn) of the NH hindered amine compound may be 2,000 or more, or 2,500 or more and 7,000 or less. The number average molecular weight (Mn) of the NH hindered amine compound may be 2,000 or more, or 2,500 or more and 6,000 or less. The number average molecular weight (Mn) of the NH hindered amine compound may be 2,000 or more, or 2,500 or more and 5,000 or less. When the number average molecular weight of the NH hindered amine compound is within these ranges, elution after gamma ray irradiation can be particularly significantly suppressed. The number average molecular weight here is determined by gel permeation chromatography (GPC).

[0030] The NH-type hindered amine compound may be a polymer containing a structural unit containing a secondary amino group that is a hindered amino group and a triazine ring, or may be a polymer containing a main chain that contains a triazine ring and a side chain group that is bonded to the main chain and contains a secondary amino group that is a hindered amino group. The NH-type hindered amine compound having a main chain that contains a triazine ring may be, for example, a compound (polymer) containing a structural unit represented by the following formula (I):

[0031] In formula (I), R １ represents an alkanediyl group having 1 to 20 carbon atoms, and R２ represents an alkyl group having 1 to 4 carbon atoms, and R ３ represents an alkyl group having 1 to 20 carbon atoms which may be substituted with a secondary amino group, R ４ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and multiple R ２ may be the same or different. １ may be a hexane-1,6-diyl group or an octane-1,8-diyl group. ２ may be a methyl group. ３ may be a group containing a secondary amino group in which R is a hindered amino group, and examples thereof include a group represented by the following formula (10): ５ represents an alkyl group having 1 to 4 carbon atoms (for example, a methyl group), and multiple R ５ may be the same or different. ４ may be a hydrogen atom, a butyl group, or a tert-octyl group.

[0032] The polypropylene resin composition may further contain a hindered amine compound other than the NH-type hindered amine compounds explained above.

[0033] The polypropylene resin composition may further contain other components as necessary. Examples of the other components include antioxidants, nucleating agents, neutralizing agents, organic peroxides, weathering agents, flame retardants, antistatic agents, plasticizers, lubricants, and copper inhibitors. The nucleating agent may include an aromatic phosphate metal salt.

[0034] The polypropylene resin composition can be obtained, for example, by melt-kneading a propylene polymer, an elastomer, an NH-type hindered amine compound, and, if necessary, other components by a conventional method. The produced polypropylene resin composition may be in the form of pellets for molding. For example, the raw materials are mixed using a mixer such as a tumbler mixer, a Henschel mixer, or a ribbon blender to prepare a mixture, and the mixture is then uniformly melt-kneaded using a single-screw extruder, a twin-screw extruder, a Banbury mixer, or the like to obtain a pelletized polypropylene resin composition.

[0035] Molded articles obtained by molding the polypropylene resin composition have excellent resistance to sterilization treatments such as γ-ray sterilization, electron beam sterilization, and high-pressure steam sterilization, and are therefore useful as medical molded articles that come into contact with various drugs during use. Examples of medical molded articles include syringe barrels and dialyzer housings. The syringes may be disposable syringes or pre-filled syringes containing a drug solution.

[0036] Fig. 1 is a plan view showing an example of a syringe. The syringe 10 shown in Fig. 1 includes an outer cylinder 11, a plunger 13, and a gasket 15 attached to the tip of the plunger 13. The outer cylinder 11 has a mouth portion 11a formed at the tip and a base end portion 11b forming an opening, and the plunger 13 is inserted into the outer cylinder 11 through the opening of the base end portion 11b.

[0037] The outer cylinder 11 is a molded article of a polypropylene resin composition. The thickness, size, etc. of the outer cylinder 11 are appropriately set within normal ranges. The plunger 13 and the gasket 15 can be selected from those commonly used in the field of syringes.

[0038] Fig. 2 is a plan view showing an example of a dialyzer. The dialyzer 20 shown in Fig. 2 comprises a cylindrical housing 21, a plurality of hollow fiber membranes 25 arranged in the longitudinal direction of the housing 21 and housed within the housing 21, and headers 22, 23 attached to both ends of the housing 21. The housing 21 has a dialysate outlet 21a provided at one end and a dialysate inlet 21b provided at the other end. One header 22 has a blood inlet 22a, and the other header 23 has a blood outlet 23a.

[0039] The housing 21 is a molded article made of a polypropylene resin composition. When the dialyzer 20 is in use, the inside of the housing 21 is filled with dialysate introduced through the dialysate inlet 21b. The thickness, size, etc. of the housing 21 are appropriately set within normal ranges. The hollow fiber membrane 25 and the headers 22, 24 can be selected from those commonly used in the field of dialyzers for dialysis.

[0040] The present invention is not limited to the following examples. 1. Raw Materials (A) Propylene-Based Polymers A-1: ​​Propylene-ethylene copolymer (MFR: 22 g / 10 min (230°C, 21.18 N), content of monomer units derived from ethylene: 2.5 mass%, melting point: 152°C) A-2: Propylene-ethylene copolymer (MFR: 6 g / 10 min (230°C, 21.18 N), content of monomer units derived from ethylene: 4.0 mass%, melting point: 142°C) A-3: Propylene homopolymer (MFR: 8 g / 10 min (230°C, 21.18 N), melting point: 164°C) (B) Elastomers B-1: B-1: Styrene-based elastomer (hydrogenated styrene-isoprene-styrene block copolymer, Hybrar 7311F, manufactured by Kuraray Co., Ltd., content of monomer units derived from styrene: 12% by mass, MFR: 0.5 g / 10 min, (190°C, 21.18 N)) B-2: Styrene-based elastomer (hydrogenated styrene-butadiene-styrene block copolymer, Tuftec H1522, manufactured by Asahi Kasei Corporation, content of monomer units derived from styrene: 30% by mass, MFR: 2 g / 10 min, (190°C, 21.18 N)) B-3: Ethylene-based elastomer (ethylene-butene-1 copolymer, Excellen VL EUL731-M, MFR: 9 g / 10 min (190°C, 21.18 N), density: 895 kg / m ３ , high-pressure polymerization, manufactured by Sumitomo Chemical Co., Ltd.) B-4: Ethylene-based elastomer (ethylene-butene-1 copolymer, Excellen VL VL700, MFR: 10 g / 10 min (190°C, 21.18 N), density: 905 kg / m ３ , high-pressure polymerization, manufactured by Sumitomo Chemical Co., Ltd.) (C) NH-type hindered amine compound C-1: A polymer represented by the following formula (n represents a positive integer) (Chimasorb 2020FDL, manufactured by BASF Japan Ltd., number average molecular weight: 2600 to 3400 g / mol) C-2: A polymer represented by the following formula (n represents a positive integer) (Uvinal 5050H, manufactured by BASF Japan Ltd., number average molecular weight: 3000 to 4000 g / mol) C-3: A polymer represented by the following formula (n represents a positive integer) (Tinuvin 622 SF, manufactured by BASF Japan Ltd., number average molecular weight: 3100 to 4000 g / mol) (D) Antioxidant D-1: Tris(2,4-di-tert-butylphenyl)phosphite (Irgafos 168, manufactured by BASF Japan Ltd.) D-2: A mixture of 50 mass% of N,N-dioctadecylhydroxylamine and 50 mass% of tris(2,4-di-tert-butylphenyl)phosphite (Irgastab FS301, manufactured by BASF Japan Ltd.) (E) Nucleating Agent E-1: Aromatic phosphate ester metal salt (A mixture of hydroxyaluminum-bis[2,2-methylene-bis(4,6-di-tert-butylphenyl)phosphate] and lithium salt of an aliphatic monocarboxylic acid having 8 to 20 carbon atoms (ADEKASTAB NA-21, manufactured by ADEKA Corporation)) (F) Neutralizer F-1: Hydrotalcite (magnesium aluminum hydroxide carbonate, DHT-4C, manufactured by Kyowa Chemical Industry Co., Ltd.)) (G) Organic peroxide G-1: A masterbatch containing 8 parts by mass of Perhexa (registered trademark) 25B (manufactured by Nippon Oil & Fats Co., Ltd.) and 92 parts by mass of a propylene-ethylene-butene-1 copolymer having a propylene content of 93.3% by mass, an ethylene content of 2.2% by mass, and a butene-1 content of 4.5% by mass, a melt flow rate of 7.0 g / 10 min, and a melting point of 140°C.

[0041] 2. Polypropylene Resin Composition (Pellets) The raw materials shown in Table 1 were sealed in a polyethylene bag and uniformly mixed using a tumbler mixer. The mixture in the polyethylene bag was melt-kneaded in a single-screw extruder with a screw diameter of 30 mm under a nitrogen atmosphere at a discharge rate of 6 kg / h and 220°C to obtain pellets of the polypropylene resin composition. Table 1 shows the content of each raw material based on the total mass of the propylene polymer and elastomer. The contents of the propylene polymer and elastomer are shown in mass %, and the contents of the other raw materials are shown in mass ppm.

[0042] 3. Evaluation Method (1) Content of Monomer Units in Propylene-Ethylene Copolymer The IR spectrum of the propylene-ethylene copolymer was measured. From the obtained IR spectrum data, the content of monomer units derived from ethylene (unit: mass%) was determined according to "(i) Method for Random Copolymers" described on page 616 of Polymer Analysis Handbook (published by Kinokuniya Shoten in 1995). Next, the content of monomer units derived from propylene in the propylene-ethylene copolymer was calculated by substituting the content of monomer units derived from ethylene into the following formula: Content of monomer units derived from propylene (mass%) = 100 (mass%) - content of monomer units derived from ethylene (mass%)

[0043] (2) Melting Point of Propylene-Based Polymer The melting point (Tm, unit: ° C.) of the propylene-based polymer was measured using a differential scanning calorimeter (TA Instruments Q2000). Approximately 5 mg of a sample was melted under a nitrogen gas atmosphere (nitrogen gas flow rate: 50 ml / min) at 200 ° C., held for 5 minutes, and cooled to 0 ° C. at a rate of 5 ° C. / min. The sample was then held at 0 ° C. for 5 minutes and heated to 230 ° C. at a rate of 5 ° C. / min. The temperature at the maximum peak of the obtained melting endothermic curve was taken as the melting point (Tm). Using the same differential scanning calorimeter, approximately 5 mg of indium was held at 110 ° C. for 2 minutes under a nitrogen atmosphere (nitrogen gas flow rate: 50 ml / min), heated to 180 ° C. at a rate of 5 ° C. / min, and measured. The melting point (Tm), which is the maximum peak temperature of the obtained melting endothermic curve, was 156.6 ° C.

[0044] (3) Melt Flow Rate The melt flow rate (MFR, unit: g / 10 min) of the polypropylene resin composition was measured in accordance with the method of JIS K 7210, condition 14, at a temperature of 230° C. and a load of 21.18 N.

[0045] (4) Stiffness Pellets of the polypropylene resin composition were preheated at 230°C for 5 minutes using a heat press molding machine, and then heated and pressed at 230°C for 5 minutes at 5 MPa to form a resin sheet. The resin sheet was cooled at 30°C for 5 minutes to obtain a resin sheet with a thickness of 1 mm. The stiffness of the obtained resin sheet was measured at a temperature of 23°C according to the method specified in JIS K7106. A high stiffness value indicates excellent rigidity.

[0046] (5) Elution Test Pellets of the polypropylene resin composition were preheated at 180°C for 5 minutes using a heat press molding machine, and then heated and pressed at 180°C for 5 minutes at 5 MPa to form a resin sheet. The resin sheet was cooled at 30°C for 5 minutes to obtain a resin sheet with a thickness of 1 mm. A resin sheet with a surface area of ​​150 cm was extracted from the resin sheet. ２ A test piece was cut out. The test piece was irradiated with gamma rays at an average dose of 50 kGy at room temperature in an air atmosphere. The test piece was then cut into a size of 5 mm wide and 25 mm long. The cut test piece was washed with ultrapure water and then dried at room temperature. The dried test piece was placed in a hard glass container, 50 mL of ultrapure water was added, and the container was tightly sealed. The hard glass container containing the test piece and ultrapure water was heated at 121°C for 1 hour using a small retort high-pressure steam sterilizer, and then left to cool to room temperature. The liquid in the container after leaving it was used as the test liquid. A hard glass container containing only ultrapure water was also treated at the same time to prepare a blank test liquid for control.

[0047] The ultraviolet absorption spectra of the test solution and blank test solution were measured based on the test method described in "(iv) Ultraviolet Absorption Spectrum" of 1.2 Extractables Test, 7.02 Plastic Pharmaceutical Container Test Method, in the 16th Edition of the Japanese Pharmacopoeia. The maximum absorbance at wavelengths of 220 to 240 nm or 241 to 350 nm was determined from the ultraviolet absorption spectrum. Test strips that satisfy the conditions of a maximum absorbance of 0.08 or less at wavelengths of 220 to 240 nm and a maximum absorbance of 0.05 or less at wavelengths of 241 to 350 nm meet the standards of the Japanese Pharmacopoeia.

[0048]

[0049] The evaluation results are shown in Table 1. It was confirmed that the polypropylene resin compositions of the examples containing a propylene-based polymer, an elastomer, and an NH-type hindered amine compound having a triazine ring had good mechanical properties and could be used to form molded articles with little elution after sterilization with gamma rays.

[0050] 10...syringe, 11...outer cylinder, 11a...mouth portion, 11b...base end portion, 13...plunger, 15...gasket, 20...dialyzer, 21...housing, 21a...dialysis solution outlet, 21b...dialysis solution inlet, 22, 23...header, 22a...blood inlet, 23a...blood outlet, 25...hollow fiber membrane

Claims

1. A polypropylene resin composition comprising: a propylene-based polymer; an elastomer; and an NH-type hindered amine compound having a triazine ring, wherein the content of the elastomer is from 1 mass% to 20 mass% based on the total amount of the propylene-based polymer and the elastomer, and the content of the NH-type hindered amine compound is from 100 mass ppm to 20,000 mass ppm based on the total amount of the propylene-based polymer and the elastomer.

2. The polypropylene resin composition according to claim 1, wherein the propylene polymer is a copolymer containing monomer units derived from ethylene in a proportion of 0.1 mass% or more and 7.0 mass% or less based on the mass of the propylene polymer.

3. The polypropylene resin composition of claim 1, wherein the elastomer comprises a styrene-based elastomer, an ethylene-based elastomer, or a combination thereof.

4. The polypropylene resin composition according to claim 1, wherein the NH-type hindered amine compound has a number average molecular weight of 2,000 or more.

5. The polypropylene resin composition according to claim 1, comprising two or more of said propylene polymers having different melting points.

6. A medical molded article comprising the polypropylene resin composition according to any one of claims 1 to 5.

7. A syringe having an outer barrel having the medical molded article according to claim 6.

8. A dialyzer comprising a housing having the medical molded article according to claim 6.

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