Propylene-based resin composition and molded article

Abstract

To provide a propylene-based resin composition for pulsed xenon sterilization which suppresses occurrence of black spots even when being subjected to pulsed xenon sterilization.SOLUTION: A propylene-based resin composition for pulsed xenon sterilization contains a propylene-based polymer (A) satisfying condition (A1), and an ultraviolet absorber (B) satisfying condition (B1), and satisfies condition (1). Condition (A1): The propylene-based polymer (A) is at least one kind selected from the group consisting of a propylene homopolymer, a propylene-based random copolymer and a propylene-based block copolymer. Condition (B1): The ultraviolet absorber (B) is at least one kind of ultraviolet absorber selected from the group consisting of a benzophenone-based ultraviolet absorber, a triazole-based ultraviolet absorber and a benzoate-based ultraviolet absorber. Condition (1): The propylene-based resin composition for pulsed xenon sterilization contains 0.01 to 0.5 pts.wt. of the ultraviolet absorber (B) with respect to 100 pts.wt. of the propylene-based polymer (A).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a propylene - based resin composition for pulsed xenon sterilization.

Background Art

[0002] In recent years, due to the rampage of novel viruses, the importance of product disinfection and sterilization has been increasing. Among them, pulsed xenon sterilization is considered as one of the methods. Polypropylene products are also used in a wide variety of applications and may require sterilization, so the importance of pulsed xenon sterilization with a specific wavelength distribution has been increasing. However, when performing pulsed xenon sterilization, there is a problem that black spots may occur in the product depending on the conditions, and countermeasures are required. There is a demand for an excellent polypropylene - based material that does not generate black spots even when pulsed xenon sterilization is performed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a propylene - based resin composition for pulsed xenon sterilization that can suppress the generation of black spots even when subjected to pulsed xenon sterilization.

Means for Solving the Problems

[0005] The present invention has been completed by finding that the above problems can be solved by containing a specific amount of a specific ultraviolet absorber in a propylene - based polymer.

[0006] That is, the present invention has the following configuration. [1]A propylene-based resin composition for pulsed xenon sterilization, which contains a propylene-based polymer (A) satisfying the following condition (A1) and an ultraviolet absorber (B) satisfying the following condition (B1) and satisfies the following condition (1). Condition (A1) The propylene-based polymer (A) is at least one selected from the group consisting of a propylene homopolymer, a propylene-based random copolymer, and a propylene-based block copolymer. Condition (B1) The ultraviolet absorber (B) is at least one ultraviolet absorber selected from the group consisting of a benzophenone-based ultraviolet absorber, a triazole-based ultraviolet absorber, and a benzoate-based ultraviolet absorber. Condition (1) The propylene-based resin composition for pulsed xenon sterilization contains 0.01 to 0.5 parts by weight of the ultraviolet absorber (B) with respect to 100 parts by weight of the propylene-based polymer (A). [2]The propylene-based resin composition for pulsed xenon sterilization according to [1], wherein the propylene-based polymer (A) further satisfies the following conditions (A2) and (A3). Condition (A2) The propylene-based polymer (A) is at least one selected from the group consisting of a propylene homopolymer, a propylene-based random copolymer having an α-olefin content of 20% by weight or less, and a propylene-based block copolymer having an α-olefin content of 20% by weight or less. Condition (A3) The melt flow rate of the propylene-based polymer (A) (based on JIS K7210, at 230 °C, under a load of 2.16 kg) is in the range of 0.5 to 300 g / 10 min. [3]The propylene-based resin composition for pulsed xenon sterilization according to any one of [1] to [2], which further contains a phenolic antioxidant (C) satisfying the following condition (C1) and satisfies the following condition (2). Condition (C1) The phenolic antioxidant (C) does not have a chroman skeleton. Condition (2) The propylene-based resin composition for pulsed xenon sterilization contains 0.01 to 1.2 parts by weight of a phenolic antioxidant (C) with respect to 100 parts by weight of the propylene-based polymer (A). [4] The propylene-based resin composition for pulsed xenon sterilization according to any one of [1] to [3], wherein the phenolic antioxidant (C) further satisfies the following condition (C2). Condition (C2) The phenolic antioxidant (C) is at least one selected from the group consisting of a phenolic antioxidant (C-1) having a hydroxyphenylpropionic acid skeleton and a phenolic antioxidant (C-2) having an isocyanurate skeleton. [5] A molded article obtained from the propylene-based resin composition for pulsed xenon sterilization according to any one of [1] to [4].

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a propylene-based resin composition for pulsed xenon sterilization that can suppress the generation of black spots even when pulsed xenon sterilization is performed.

Brief Description of the Drawings

[0008]

Figure 1

Embodiments for Carrying Out the Invention

[0009] The propylene-based resin composition for pulsed xenon sterilization of the present invention is characterized in that it contains 0.01 to 0.5 parts by weight of a specific ultraviolet absorber (B) with respect to 100 parts by weight of the propylene-based polymer (A) (hereinafter also referred to as "the propylene-based resin composition of the present invention"). Hereinafter, the components constituting the propylene resin composition of the present invention, the production method of the resin composition, and the molded article will be described in detail.

[0010] [I] Components constituting the propylene-based resin composition 1. Propylene-based polymer (A) Condition (A1) The propylene-based polymer (A) is at least one selected from the group consisting of a propylene homopolymer, a propylene random copolymer, and a propylene block copolymer. The propylene random copolymer and the propylene block copolymer are copolymers of propylene and an α-olefin. Examples of the α-olefin used in the copolymerization include α-olefins having 2 to 20 carbon atoms excluding propylene, such as ethylene, butene-1, hexene-1, octene-1, etc. One kind or two or more kinds of α-olefins copolymerized with propylene may be used. Among these, ethylene and butene-1 are preferred. More preferably, ethylene is preferred. Specific examples of the copolymer include propylene-ethylene copolymer, propylene-ethylene-diene copolymer, propylene-butene-1 copolymer, propylene-hexene-1 copolymer, propylene-octene-1 copolymer, etc. Among these, propylene-ethylene copolymer and propylene-butene-1 copolymer are particularly preferred.

[0011] In the propylene-based resin composition of the present invention, the propylene-based polymer (A) is preferably at least one selected from the group consisting of a propylene homopolymer, a propylene random copolymer having an α-olefin content of 20% by weight or less, and a propylene block copolymer having an α-olefin content of 20% by weight or less (Condition (A2)). When a propylene block copolymer is used as the propylene-based polymer (A), in the propylene block copolymer, the amount of α-olefin is more preferably 0.05 to 10.0% by weight, and even more preferably 0.1 to 5.0% by weight. Of course, at the polymerization stage, so-called polypropylene-based polymer alloys in which a rubber component such as EPR is introduced as a soft segment into a hard segment composed of a polypropylene-based crystalline phase can also be used.

[0012] In addition, when using a propylene-based polymer (A) as a propylene random copolymer (hereinafter sometimes referred to as a random copolymer), the amount of α-olefin in the random copolymer is more preferably 0.1 to 10.0% by weight. By setting the amount of α-olefin in the random copolymer in such a range when using a propylene random copolymer as the propylene-based polymer (A), it becomes possible to further improve transparency, various mechanical properties, bleedability on the surface of the molded product, etc. That is, if the amount of α-olefin in the random copolymer is less than 0.1%, transparency and impact resistance may deteriorate. Conversely, if it exceeds 10.0%, the rigidity may decrease, and there is also a high possibility that bleeding may occur on the surface of the molded product.

[0013] In the propylene-based polymer (A), any of a propylene homopolymer, a propylene-based random copolymer, and a propylene-based block copolymer can be used, but from the viewpoint of transparency, a propylene-based random copolymer is desirable.

[0014] The glass transition temperature of the propylene-based polymer (A) is preferably -100 to 20°C.

[0015] Also, the propylene-based polymer (A) may be of one type or a mixture of two or more types may be used.

[0016] The propylene-based polymer (A) used in the present invention desirably has a melt flow rate (MFR) of 0.5 to 300 g / 10 minutes at 230°C and a load of 2.16 kg (condition (A3)). When the MFR is within this range, it gives a resin composition suitable for the rigidity and impact resistance of the resin composition and the high production rate derived from the molding temperature. If the MFR is less than 0.5 g / 10 minutes, molding becomes difficult. On the other hand, if it exceeds 300 g / 10 minutes, there is a risk that good impact resistance cannot be obtained. Here, the MFR at 230°C is a value measured under a load of 2.16 kg at 230°C in accordance with JIS K7210.

[0017] When using a propylene homopolymer as the propylene-based polymer (A), the isotactic pentad fraction (mmmm) is desirably 90% or more, preferably 94% or more, more preferably 97% or more. If the isotactic pentad fraction (mmmm) is less than 90%, due to a decrease in rigidity and heat distortion temperature, the molded product may be liable to deform during molding. Conversely, the higher the stereoregularity, the higher the rigidity and heat resistance, and deformation of the molded product can be prevented. Here, the isotactic pentad fraction (mmmm) is 13 a value measured by the C-NMR method.

[0018] When using a propylene-based block copolymer, preferably an ethylene-propylene block copolymer (hereinafter, the ethylene-propylene block copolymer may be referred to as the "block copolymer") as the propylene-based polymer (A), the polypropylene segment in the block copolymer preferably accounts for 70 to 99% by weight, more preferably 86 to 98% by weight, and the ethylene-propylene copolymer segment preferably accounts for 1 to 30% by weight, more preferably 2 to 14% by weight. When each segment is within this range, it is suitable for improving various mechanical properties of the resin composition.

[0019] Also, the isotactic pentad fraction (mmmm) of the polypropylene segment is desirably 90% or more, preferably 94% or more, more preferably 97% or more. If the isotactic pentad fraction (mmmm) is less than 90%, the molded product is liable to deform during molding. Here, the isotactic pentad fraction (mmmm) is 13 a value measured by the C-NMR method.

[0020] Furthermore, the total ethylene content in the above block copolymer is 0.5 to 12% by weight, preferably 2 to 9% by weight. Being within this range is suitable for improving the impact resistance and rigidity of the resin composition. If the total ethylene content is less than 0.5% by weight, the impact resistance may be insufficient, and if it exceeds 12% by weight, the rigidity may be insufficient. Here, the ethylene content is the value measured by the IR method.

[0021] The method for producing the propylene-based polymer (A) is not particularly limited, but a polymerization method using a stereoregular catalyst is preferred. Examples of the stereoregular catalyst include Ziegler catalysts and metallocene catalysts.

[0022] Examples of the Ziegler catalyst include titanium halide compounds such as titanium trichloride, titanium tetrachloride, and trichloroethoxytitanium; contact products of the titanium halide compound and a magnesium compound typified by magnesium halide; binary catalysts composed of a transition metal component and an organoaluminum compound or their halides, hydrides, alkoxides, etc.; and ternary catalysts obtained by adding an electron-donating compound containing nitrogen, carbon, phosphorus, sulfur, oxygen, silicon, etc. to these components.

[0023] The metallocene catalyst is a catalyst composed of (i) a transition metal compound of Group 4 of the periodic table containing a ligand having a cyclopentadienyl skeleton (so-called metallocene compound), (ii) a cocatalyst capable of reacting with the metallocene compound to be activated to a stable ionic state, and, if necessary, (iii) an organoaluminum compound, and any known catalyst can be used. The metallocene compound is preferably a crosslinked metallocene compound capable of stereoregular polymerization of propylene, more preferably a crosslinked metallocene compound capable of isotactic polymerization of propylene.

[0024] (i) Examples of the metallocene compound are disclosed in each of the gazettes of JP-A-60-35007, JP-A-61-130314, JP-A-63-295607, JP-A-1-275609, JP-A-2-41303, JP-A-2-131488, JP-A-2-76887, JP-A-3-163088, JP-A-4-300887, JP-A-4-211694, JP-A-5-43616, JP-A-5-209013, JP-A-6-239914, JP-T-7-504934, and JP-A-8-85708.

[0025] Furthermore, specifically, methylenebis(2-methylindenyl)zirconium dichloride, ethylenebis(2-methylindenyl)zirconium dichloride, ethylene 1,2-(4-phenylindenyl)(2-methyl-4-phenyl-4H-azulenyl)zirconium dichloride, isopropylidene(cyclopentadienyl)(fluorenyl)zirconium dichloride, isopropylidene(4-methylcyclopentadienyl)(3-t-butylindenyl)zirconium dichloride, dimethylsilylene(2-methyl-4-t-butyl-cyclopentadienyl)(3'-t-butyl-5'-methyl-cyclopentadienyl)zirconium dichloride, dimethylsilylenebis(indenyl)zirconium dichloride, dimethylsilylenebis(4,5,6,7-tetrahydroindenyl)zirconium dichloride, dimethylsilylenebis[1-(2-methyl-4-phenylindenyl)]zirconium dichloride, dimethylsilylenebis[1-(2-ethyl-4-phenylindenyl)]zirconium dichloride, dimethylsilylenebis[4-(1-phenyl-3-methylindenyl)]zirconium dichloride, dimethylsilylene(fluorenyl)t-butylamidozirconium dichloride, methylphenylsilylenebis[1-(2-methyl-4,(1-naphthyl)-indenyl)]zirconium dichloride, dimethylsilylenebis[1-(2-methyl-4,Examples of zirconium compounds include (5 - benzoindenyl)zirconium dichloride, dimethylsilylenebis[1-(2 - methyl - 4 - phenyl - 4H - azulenyl)]zirconium dichloride, dimethylsilylenebis[1-(2 - ethyl - 4-(4 - chlorophenyl)-4H - azulenyl)]zirconium dichloride, dimethylsilylenebis[1-(2 - ethyl - 4 - naphthyl - 4H - azulenyl)]zirconium dichloride, diphenylsilylenebis[1-(2 - methyl - 4-(4 - chlorophenyl)-4H - azulenyl)]zirconium dichloride, dimethylsilylenebis[1-(2 - ethyl - 4-(3 - fluorobiphenylyl)-4H - azulenyl)]zirconium dichloride, dimethylgermylenebis[1-(2 - ethyl - 4-(4 - chlorophenyl)-4H - azulenyl)]zirconium dichloride, dimethylgermylenebis[1-(2 - ethyl - 4 - phenylindenyl)]zirconium dichloride, etc. In the above, compounds in which zirconium is replaced by titanium or hafnium can also be used in the same manner. In some cases, mixtures of zirconium compounds and hafnium compounds, etc. can also be used. Further, chloride can be replaced by other halogen compounds, hydrocarbon groups such as methyl, isobutyl, benzyl, amide groups such as dimethylamide, diethylamide, alkoxide groups such as methoxy group, phenoxy group, hydride group, etc. Among these, metallocene compounds in which the indenyl group or azulenyl group is cross - linked with a silicon or germyl group are preferred.

[0026] Also, the metallocene compound may be used by being supported on an inorganic or organic compound carrier. As the carrier, porous compounds of inorganic or organic compounds are preferred. Specifically, ion - exchangeable layered silicates, zeolites, SiO2, Al2O3, silica - alumina, MgO, ZrO2, TiO2, B2O3, CaO, ZnO, BaO, ThO2, etc. inorganic compounds, porous polyolefins, styrene - divinylbenzene copolymers, olefin - acrylic acid copolymers, etc. organic compounds composed of these, or mixtures thereof can be mentioned.

[0027] (ii) As cocatalysts that can react with the metallocene compound to be activated to a stable ionic state, there may be mentioned organoaluminum oxy compounds (for example, aluminoxane compounds), ion-exchangeable layered silicates, Lewis acids, boron-containing compounds, ionic compounds, fluorine-containing organic compounds, and the like.

[0028] (iii) As organoaluminum compounds, there may be mentioned trialkylaluminums such as triethylaluminum, triisopropylaluminum, and triisobutylaluminum, dialkylaluminum halides, alkylaluminum sesquihalides, alkylaluminum dihalides, alkylaluminum hydrides, organoaluminum alkoxides, and the like.

[0029] As a method for producing the propylene-based polymer (A), there may be mentioned a slurry method using an inert solvent, a solution method, a gas-phase method substantially without using a solvent, or a bulk polymerization method using a polymerization monomer as a solvent, in the presence of the above catalyst. For example, in the case of the slurry polymerization method, it can be carried out in an inert hydrocarbon such as n-butane, isobutane, n-pentane, isopentane, hexane, heptane, octane, cyclohexane, benzene, toluene, xylene or a liquid monomer. The polymerization temperature is usually -80 to 150°C, preferably 40 to 120°C. The polymerization pressure is preferably 1 to 60 atm, and the molecular weight of the resulting propylene-based polymer can be adjusted with hydrogen or other known molecular weight regulators. The polymerization is carried out by a continuous or batch reaction, and the conditions may be the commonly used conditions. Further, the polymerization reaction may be carried out in one stage or in multiple stages.

[0030] Also, when blending a polymer produced using a metallocene catalyst with the propylene-based polymer (A), it is more preferable that the propylene-based polymer (A) is produced using a metallocene catalyst because of better compatibility.

[0031] 2. Ultraviolet absorber (B) The propylene-based resin composition of the present invention contains an ultraviolet absorber (B) that satisfies the following condition (B1), and the addition amount of the ultraviolet absorber (B) is 0.01 to 0.5 with respect to 100 parts by weight of the propylene-based polymer (A) (condition (1)). Condition (B1) The ultraviolet absorber (B) is at least one ultraviolet absorber selected from the group consisting of benzophenone-based ultraviolet absorbers, triazole-based ultraviolet absorbers, and benzoate-based ultraviolet absorbers. By containing the ultraviolet absorber (B) within the above range, the propylene-based resin composition of the present invention can suppress the generation of black spots due to pulsed xenon sterilization.

[0032] The ultraviolet absorber (B) used in the propylene-based resin composition of the present invention is at least one ultraviolet absorber selected from the group consisting of benzophenone-based ultraviolet absorbers, triazole-based ultraviolet absorbers, and benzoate-based ultraviolet absorbers (condition (B1)) By using the above ultraviolet absorber as the ultraviolet absorber (B), it is considered that the generation of black spots in the propylene-based resin composition can be suppressed due to its ultraviolet absorption wavelength spectrum characteristics of absorbing ultraviolet rays having wavelengths at which black spots are likely to occur in the propylene-based resin composition.

[0033] Examples of the benzophenone-based ultraviolet absorber include 2-hydroxy-4-methoxybenzophenone (product example: Seesorb 101 manufactured by Cipro Kasei Co., Ltd.), 2-hydroxy-4-n-octoxybenzophenone (product example: Seesorb 102 manufactured by Cipro Kasei Co., Ltd.), 2-hydroxy-4-n-dodecyloxybenzophenone (product example: Seesorb 103 manufactured by Cipro Kasei Co., Ltd.), 2-hydroxy-4-benzyloxybenzophenone (product example: Seesorb 105 manufactured by Cipro Kasei Co., Ltd.), and the like.

[0034] Examples of triazole-based ultraviolet absorbers include 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole (product example: Tinuvin 326 manufactured by BASF), 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol] (product example: Adegastab LA-31 manufactured by ADEKA), 2-[2'-hydroxy-3,5'-bis(α,α-dimethylbenzyl)phenyl]benzotriazole (product example: Tinuvin 234 manufactured by BASF), 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole (product example: Seesorb 709 manufactured by Cypro Kasei Co., Ltd.), and the like.

[0035] Examples of benzoate-based ultraviolet absorbers include 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate (product example: Seesorb 712 manufactured by Cypro Kasei Co., Ltd.), 3,5-di-t-butyl-4-hydroxybenzoic acid, n-hexadecyl ester (product example: Cyasorb UV-2908 manufactured by Cytec), and the like.

[0036] 3. Phenolic antioxidant (C) The propylene-based resin composition of the present invention can preferably further contain a phenolic antioxidant (C) that satisfies the following condition (C1). Condition (C1) The phenolic antioxidant (B) does not have a chroman skeleton. By containing a phenolic antioxidant (C) that satisfies the above conditions, the propylene-based resin composition of the present invention can further suppress the generation of black spots due to pulsed xenon lamp sterilization.

[0037] The addition amount of the phenolic antioxidant (C) that satisfies the condition (C1) used in the propylene-based resin composition of the present invention is preferably 0.01 to 1.2 parts by weight (condition (2)), more preferably 0.05 to 0.80 parts by weight, and still more preferably 0.10 to 0.50 parts by weight with respect to 100 parts by weight of the propylene-based polymer (A). When the addition amount is 0.01 part by weight or more, the effect as an antioxidant is sufficient, and when it is 1.2 parts by weight or less, it is also preferable from an economic point of view in terms of the corresponding effect. That is, when the addition amount of the phenolic antioxidant (C) is less than 0.01 part by weight with respect to 100 parts by weight of the propylene-based polymer (A), a sufficient antioxidant effect may not be obtained, and when it exceeds 1.2 parts by weight, the antioxidant effect reaches a plateau, so it may be difficult to obtain an effect commensurate with the addition amount of the phenolic antioxidant (C).

[0038] Examples of the phenolic antioxidant (C) that satisfies the condition (C1) include phenolic antioxidants having a hydroxyphenylpropionic acid skeleton and phenolic antioxidants having an isocyanurate skeleton.

[0039] Examples of the phenolic antioxidant having a hydroxyphenylpropionic acid skeleton include, for example, 1010: tetrakis[methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)]methane, 1076: n-octadecyl-β-(4 , -hydroxy 3 , ,5 , -di-t-butylphenyl)propionate, AO80: 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]―2,4,8,10-tetraoxaspiro[5,5]undecane, and the like.

[0040] Examples of the phenolic antioxidant having an isocyanurate skeleton include, for example, AO20: tris(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, CY1790: 1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, and the like.

[0041] In addition, examples of other phenolic antioxidants C other than the above include, for example, 1330: 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, and the like.

[0042] The phenolic antioxidant (C) that satisfies the condition (C1) used in the propylene-based resin composition of the present invention is preferably at least one selected from the group consisting of a phenolic antioxidant (C-1) having a hydroxyphenylpropionic acid skeleton and a phenolic antioxidant (C-2) having an isocyanurate skeleton (condition (C2)). By using the above phenolic antioxidant as the phenolic antioxidant (C), the generation of black spots due to pulsed xenon sterilization can be more efficiently suppressed.

[0043] 4. Additives To the propylene-based resin composition of the present invention, at least one additive selected from the group consisting of a phosphorus-based antioxidant, an amine-based antioxidant, and a phenolic antioxidant having a chroman skeleton can be further added. By using the above additive, the generation of black spots due to pulsed xenon sterilization can be more effectively suppressed.

[0044] The addition amount of the above additive is preferably 0.01 to 1 part by weight, more preferably 0.02 to 0.8 part by weight, still more preferably 0.03 to 0.5 part by weight, particularly preferably 0.04 to 0.3 part by weight, and most preferably 0.04 to 0.2 part by weight, based on 100 parts by weight of the propylene-based polymer (A). When the addition amount of the above additive is 0.01 part by weight or more, the effect as an antioxidant is sufficient, and when it is 1 part by weight or less, it is preferable from an economic point of view in terms of the matching effect. That is, when the addition amount of the above additive is less than 0.01 part by weight based on 100 parts by weight of the propylene-based polymer (A), a sufficient black spot generation suppression effect may not be obtained, and when it exceeds 1.2 parts by weight, the effect of the additive reaches its peak, so it may be difficult to obtain an effect commensurate with the addition amount of the additive.

[0045] As phosphorus-based antioxidants, for example, PEP36: bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol-di-phosphite, PEP8: di-stearyl-pentaerythritol-di-phosphite, PEP24: bis(2,4-di-t-butylphenyl)pentaerythritol-di-phosphite, IF168: tris(2,4-di-t-butylphenyl)phosphite, PEPQ: tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene-di-phosphonite, etc. can be mentioned.

[0046] As amine-based antioxidants, for example, compounds represented by the following formula (1) and the following formula (2) can be mentioned.

[0047]

Chemical formula

[0048]

Chemical formula

[0049] As phenolic antioxidants having a chroman skeleton, for example, vitamin E-based antioxidants such as the following formula (3) can be mentioned.

[0050]

Chemical formula

[0051] In addition, for example, thio-based antioxidants such as di-stearyl-β,β'-thio-di-propionate, di-myristyl-β,β'-thio-di-propionate, di-lauryl-β,β'-thio-di-propionate, etc. can also be used.

[0052] In the propylene-based resin composition of the present invention, in addition to the above-described components, additives such as neutralizing agents and nucleating agents can be added within a range that does not inhibit the effects of the present invention.

[0053] Examples of neutralizing agents include higher fatty acid metal salts such as calcium stearate and zinc stearate, hydrotalcite (trade name: DHT-4A, a magnesium aluminum composite hydroxide salt represented by the following formula (4) manufactured by Kyowa Chemical Industry Co., Ltd.), Mizukarak (trade name, a lithium aluminum composite hydroxide salt represented by the following formula (5) manufactured by Mizusawa Chemical Industry Co., Ltd.), and the like. Mg 1-x Al x (OH)2(CO3) x / 2 ·mH2O …(4) [In the formula, x satisfies 0 < x ≤ 0.5, and m is a number of 3 or less.] [Al2Li(OH)6] n X·mH2O …(5) [In the formula, X is an inorganic or organic anion, n is the valence of the anion (X), and m is 3 or less.]

[0054] As the nucleating agent, known nucleating agents can be used. Examples include aromatic phosphate metal salts, sterically hindered amide compounds, organic dicarboxylic acid metal salts, aromatic carboxylic acid metal salts, sorbitol-based or its derivatives, nonitol-based or its derivatives, metal salts of diterpenic acids, or polymer nucleating agents, etc.

[0055] Furthermore, in addition, various known additives, such as antistatic agents, lubricants, dispersants such as fatty acid metal salts, dyes, pigments, etc., can be blended within a range that does not impair the object of the present invention.

[0056] [2] Propylene-based resin composition The propylene-based resin composition of the present invention has a remarkable effect of suppressing the generation of black spots even when subjected to pulsed xenon lamp sterilization. In a normal weather resistance tester using a xenon lamp, ultraviolet and infrared control filters are used as necessary to make the wavelength closer to sunlight. However, in the atmosphere when sterilizing by irradiating pulsed xenon, these filters are not used. Therefore, unlike the conditions of the xenon lamp weather resistance test, light having a wide spectral distribution from ultraviolet rays that have a large impact on deterioration by light to infrared rays that have a large impact on deterioration by temperature is simultaneously irradiated onto the propylene-based resin. Regarding the remarkable effect that the generation of black spots is suppressed even when the propylene-based resin composition of the present invention is subjected to pulsed xenon sterilization, the details of its mechanism of action are not clear. However, as described above, when irradiating pulsed xenon, light having a wider spectral distribution than conventionally assumed is simultaneously irradiated onto the propylene-based resin, and its action and the resin deterioration mechanism are considered to be different from the conventional ones. Therefore, it is considered that the ultraviolet absorber (B) used in the propylene-based resin composition of the present invention exhibits a remarkable effect of preventing the deterioration of the propylene-based polymer (A) and suppressing the generation of black spots under such complex circumstances.

[0057] [3] Method for producing propylene-based resin composition The propylene-based resin composition of the present invention can be obtained by charging the propylene-based polymer (A), the ultraviolet absorber (B), and further, if necessary, a phenolic antioxidant (C) and additives into a Henschel mixer, a super mixer, a ribbon blender, etc., mixing them, and then melt-kneading them at a temperature range of 190 to 260°C using a normal single-screw extruder, twin-screw extruder, Banbury mixer, plavender, roll, etc.

[0058] [4] Molded article Another embodiment of the present invention is a molded article obtained from the propylene-based resin composition of the present invention (hereinafter also referred to as "the molded article of the present invention"). The molded article of the present invention can be obtained by molding the above propylene-based resin composition using a known extrusion molding machine, injection molding machine, blow molding machine.

[0059] Examples of the molded article of the present invention include injection molded articles, extrusion molded articles, hollow molded articles, compression molded articles, calendered molded articles, laminated molded articles, fluid dipping molded articles, blow molded articles, slush molded articles, rotational molded articles, thermoformed articles, CCM molded articles, etc. Specifically, food containers (pudding containers, jelly containers, yogurt containers, steamed egg containers, instant ramen containers, chilled coffee containers, dessert containers, bento boxes, etc.), caps (PET bottle caps, one-piece caps, two-piece caps, instant coffee caps, etc.), medical instruments and containers (disposable syringes and their parts, catheter tubes, infusion bags, blood bags, vacuum blood collection tubes, surgical non-woven fabrics, blood filters, blood circuits, etc. disposable instruments, parts of artificial organs such as artificial lungs and artificial anuses, dialyzers, prefilled syringes, kit preparations, drug containers, test tubes, sutures, poultice substrates, parts of dental materials, parts of orthopedic materials, contact lens cases, PTP, SP subcontracting, P vials, ophthalmic drug containers, chemical solution containers, long-term storage containers for liquids, etc.), medical containers (infusion packs, daily necessities (clothing cases, buckets, washbasins, writing utensils), automotive parts (instrument panels, bumpers, lamp bodies, etc.), electrical parts (casings of various electrical appliances, etc.), solar cell encapsulants, films, fibers, sheets, etc.).

Examples

[0060] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. The measurement methods, evaluation methods, resins, and additives used in the examples and comparative examples are as follows.

[0061] <1. Measurement methods and evaluation methods of physical property values> (1) Calculation of ethylene content of propylene-based polymer (A) 13 Using an ethylene-propylene random copolymer whose composition was assayed by C-NMR as a reference substance, the ethylene content in the random copolymer was measured by infrared spectroscopy using the characteristic absorption band at 733 cm -1 Pellets were formed into a film with a thickness of about 500 μm by press molding.

[0062] (2) Melt flow rate (MFR): It was measured in accordance with JIS K7210 (230°C, 2.16 kg load).

[0063] (3) Pulsed xenon sterilization test · A molded product (12 cm × 12 cm × 2 mm plate) was molded using an injection molding machine, and from this, an evaluation molded product (6.5 cm × 3.5 cm × 2 mm plate) was obtained by punching. The obtained molded product was irradiated with pulsed xenon light of 6.0 J / cm 2 and 9.0 J / cm 2 for a light emission time of 0.5 msec, and the presence or absence of black spots was visually confirmed. (4) Hue YI before and after heating · A test piece of 12 cm × 12 cm × 2 mm was injection molded at a molding temperature of 200°C and a mold temperature of 40°C, and the injection test piece was treated at 60°C for 5 hours. The hue YI before and after the treatment was measured.

[0064] <2. Resin, additive> 2-1. Polypropylene-based polymer (A) (1) Manufacturing method of PP-1 The catalyst, polymerization equipment, and polymerization pressure and temperature setting conditions described in JP-A-2008-150466 were used to polymerize the corresponding polymer. Hydrogen as a molecular weight regulator in the first reactor was continuously supplied so that the hydrogen / propylene molar ratio was 0.013, and ethylene was continuously supplied together with propylene so that the ethylene / propylene molar ratio was 0.020. Separately, triethylaluminum was supplied so that the molar ratio was 100 with respect to 1 mol of Ti atoms in the catalyst, and the catalyst amount was supplied so that the production rate in the first reactor was 9 kg / h. The powder was withdrawn so that the holding level in the first reactor was 50% by volume and supplied to the second reactor. Hydrogen as a molecular weight regulator in the second reactor was continuously supplied so that the hydrogen / propylene molar ratio was 0.016, and ethylene was continuously supplied together with propylene so that the ethylene / propylene molar ratio was 0.036. At this time, the production rate after the second reactor was 14 kg / h. The powder was withdrawn so that the holding level in the second reactor was 60% by volume, and the withdrawn powder was supplied with nitrogen gas containing moisture to stop the reaction, obtaining a propylene-ethylene random copolymer. The MFR of the obtained propylene-ethylene random copolymer was 9.1 g / 10 min, and the ethylene content was 4.2% by weight.

[0065] (2) Production method of PP-2 [Prepolymerization treatment of solid catalyst component] A 3-L autoclave equipped with a stirring device sufficiently purged with nitrogen was charged with 90 g of a solid catalyst component (A) (THC-C-125 purchased from Toho Titanium Co., Ltd., a solid catalyst component containing titanium, magnesium, and halogen as essential components) and 1.5 L of purified n-heptane to introduce a slurry with a concentration of 60 g / L. Subsequently, an n-heptane dilution of triethylaluminum containing 10 g of triethylaluminum was introduced into the autoclave. Then, 270 g of propylene was supplied over 3 hours. After the supply of propylene was completed, the reaction was continued for an additional 10 minutes. The prepolymerization temperature was 30°C. The resulting slurry was withdrawn from the autoclave, and the reaction product was thoroughly washed with purified n-heptane. Subsequently, vacuum drying was performed to obtain the component (A) after prepolymerization. This component (A) after prepolymerization contained 2.0 g of polypropylene per 1 g of the solid catalyst component.

[0066] [Polymerization of Propylene-Ethylene-1-Butene Terpolymer] Using a horizontal polymerizer (horizontal reactor) with stirring blades schematically shown in Fig. 1, the polymerization of propylene / ethylene / 1-butene terpolymer was carried out. In a horizontal polymerizer 6 (L / D = 4.3, internal volume 100 liters), 0.29 g / h of component (A) after prepolymerization was fed from pipe 1, and triethylaluminum was used as the organoaluminum compound (component (B)) such that the Al / Mg molar ratio was 10 with respect to Mg in component (A) after prepolymerization, and diisopropyldimethoxysilane was used as the organosilicon compound (component (C)) such that the ratio with Al in component (B) (Al / Si molar ratio) was 1.5 and was fed from pipe 2. The reaction temperature was set to 58°C - 61°C - 64°C from the upstream side for each of the three equal-volume parts of the polymerization reactor 6. While maintaining the reaction pressure at 1.90 MPa and the stirring speed at 28 rpm, the hydrogen concentration in the gas phase in the polymerizer was adjusted to the hydrogen / (ethylene + propylene + 1-butene) molar ratio shown in Table 1, the ethylene concentration to the ethylene / (ethylene + propylene + 1-butene) molar ratio shown in Table 1, and the 1-butene concentration to the 1-butene / (ethylene + propylene + 1-butene) molar ratio shown in Table 1. Hydrogen gas and ethylene were continuously supplied from circulation pipe 3, and 1-butene was continuously supplied from pipe 4 to adjust the MFR, ethylene content, and 1-butene content of the polymer. The heat of reaction (heat of polymerization) was removed by the heat of vaporization of the raw material liquefied propylene supplied from pipe 4. The unreacted gas discharged from the polymerizer 6 was cooled and condensed outside the reactor system through pipe 5 and refluxed to the polymerizer 6 from pipe 3. The produced polymer was continuously withdrawn from the polymerizer 6 through pipe 7 equipped with a blow case such that the holding level of the polymer was 50% by volume of the reaction volume. The production rate of the propylene / ethylene / 1-butene terpolymer at this time was 10 kg / h, and the catalytic activity of the catalyst for propylene polymerization determined from the catalyst feed amount per hour (0.29 g / h) and the production rate of the propylene / ethylene / 1-butene terpolymer (10 kg / h) was approximately 34,000 g / g-catalyst. The MFR of the obtained propylene / ethylene / 1-butene terpolymer was 7 g / 10 min, the ethylene content was 2.8% by weight, and the 1-butene content was 2% by weight.

[0067] 2-2. Ultraviolet Absorbent (B) · TNV326 (triazole-based): Tinuvin 326 (manufactured by BASF). 2-(2'-Hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole. · SS102 (benzophenone-based): Seesorb 102 (manufactured by Cipro Kasei Co., Ltd.). 2-Hydroxy-4-n-octoxybenzophenone. · TNV120 (benzoate-based): Seesorb 712 (manufactured by Cipro Kasei Co., Ltd.). 2,4-Di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate.

[0068] 2-3. Phenolic Antioxidant (C) · IR1010: Irganox 1010 (manufactured by BASF). Tetrakis[methylene-3-(3',5'-di-t-butyl-4-hydroxyphenyl)propionate]methane.

[0069] 2-4. Additives HALS: Hindered amine light stabilizer not corresponding to ultraviolet absorbent (B) · TNV944: Chimassorb 944LD (manufactured by BASF). Poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}].[[]]

[0070] Antioxidant · IF168: Irgafos 168 (manufactured by BASF). Tris(2,4-di-t-butylphenyl)phosphite

[0071] Neutralizing Agent · DHT4A: DHT-4A (manufactured by Kyowa Chemical Industry Co., Ltd.). Magnesium·aluminum·hydroxide·carbonate·hydrate.

[0072] <3. Examples 1 to 15, Comparative Examples 1 to 4> Each polymer and additive were prepared at the compounding ratios (parts by weight) shown in Tables 1 and 2, dry-blended using a super mixer, and then melt-kneaded at a die outlet temperature of 220 °C under a nitrogen atmosphere using a twin-screw extruder TEM-35B manufactured by Toshiba Machine Co., Ltd., and pelletized. Using the obtained pellets, evaluation was carried out according to the above evaluation method. The evaluation results are shown in Tables 1 and 2.

[0073]

Table 1

[0074]

Table 2

[0075] ·Regarding Table 1 Example 1 is an example in which a triazole-based additive was added, Example 2 is an example in which a benzophenone-based additive was added, and Example 3 is an example in which a benzoate-based additive was added. It can be seen that the generation of black spots is suppressed compared to Comparative Example 1 in which these were not added. Examples 4 to 6 are examples in which IR1010, which is a phenolic antioxidant (C-1), a phosphorus-based antioxidant IF168, and a neutralizing agent were added as additives, and it can be seen that black spots are further suppressed. Comparative Example 2 is an example in which a HALS was added instead of the ultraviolet absorber defined in the present invention. Although the number of black spots is smaller compared to Comparative Example 1 in which no additive was added, it can be seen that there are more black spots compared to Examples 1 to 6 of the present invention. Also, Comparative Example 3 is an example in which IR1010, which is a phenolic antioxidant (C-1), a phosphorus-based antioxidant IF168, and a neutralizing agent were added without adding the ultraviolet absorber defined in the present invention. It can be seen that there are more black spots compared to Examples 1 to 6 in which the ultraviolet absorber defined in the present invention was added.

[0076] ·Regarding Table 2 Table 2 shows an example where the propylene-based polymer was changed from Table 1 and experiments were conducted with various formulations. It can be seen that black dots were suppressed in all examples. On the other hand, Comparative Example 4 is an example where the amount of ultraviolet absorber was further increased compared to Example 14, but it can be seen that the hue YI is poor and not preferable.

[0077] [Explanation of Drawing Signs] 1, 2: Catalyst Component Supply Pipe (Pipe) 3: Raw Material Mixed Gas Supply Pipe (Circulation Pipe) 4: Raw Material Propylene, 1-Butene Supply Pipe (Pipe) 5: Unreacted Gas Extraction Pipe (Pipe) 6: Polymerizer (Horizontal Polymerizer) 7: Downstream End of Reactor (Pipe)

Claims

1. A propylene-based resin composition for pulsed xenon sterilization, comprising a propylene-based polymer (A) satisfying the following condition (A1) and an ultraviolet absorber (B) satisfying the following condition (B1), and satisfying the following condition (1). Condition (A1) The propylene-based polymer (A) is at least one selected from the group consisting of a propylene homopolymer, a propylene-based random copolymer, and a propylene-based block copolymer. Condition (B1) The ultraviolet absorber (B) is at least one ultraviolet absorber selected from the group consisting of a benzophenone-based ultraviolet absorber, a triazole-based ultraviolet absorber, and a benzoate-based ultraviolet absorber. Condition (1) The propylene-based resin composition for pulsed xenon sterilization contains 0.01 to 0.5 parts by weight of the ultraviolet absorber (B) with respect to 100 parts by weight of the propylene-based polymer (A).

2. The propylene-based resin composition for pulsed xenon sterilization according to Claim 1, wherein the propylene-based polymer (A) further satisfies the following conditions (A2) and (A3). Condition (A2) The propylene-based polymer (A) is at least one selected from the group consisting of a propylene homopolymer, a propylene-based random copolymer having an α-olefin content of 20% by weight or less, and a propylene-based block copolymer having an α-olefin content of 20% by weight or less. Condition (A3) The melt flow rate of the propylene-based polymer (A) (in accordance with JIS K7210, at 230 °C, under a load of 2.16 kg) is in the range of 0.5 to 300 g / 10 min.

3. The propylene-based resin composition for pulsed xenon sterilization according to Claim 1, further containing a phenolic antioxidant (C) satisfying the following condition (C1) and satisfying the following condition (2). Condition (C1) The phenolic antioxidant (C) does not have a chroman skeleton. Condition (2) The propylene-based resin composition for pulsed xenon sterilization contains 0.01 to 1.2 parts by weight of the phenolic antioxidant (C) with respect to 100 parts by weight of the propylene-based polymer (A).

4. The propylene-based resin composition for pulsed xenon sterilization according to Claim 4, wherein the phenolic antioxidant (C) further satisfies the following condition (C2). Condition (C2) The phenolic antioxidant (C) is at least one selected from the group consisting of a phenolic antioxidant (C-1) having a hydroxyphenylpropionic acid skeleton and a phenolic antioxidant (C-2) having an isocyanurate skeleton.

5. A molded article obtained from the propylene-based resin composition for pulsed docenone sterilization according to any one of claims 1 to 4.

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