Polypropylene resin composition and molded article

Abstract

To provide a propylene-based resin composition with an obtained molded body having excellent transparency, impact resistance, and machinability.SOLUTION: Provided are a propylene-based resin composition and a molded body, the composition comprising: 87-97 pts.mass of a propylene-based polymer (A) which satisfies requirements (A1) to (A4); 3-13 pts.mass of an ethylene-α-olefin copolymer (B) which satisfies requirements (B1)-(B2) (where a total of (A) and (B) is set to 100 pts.mass); and 0.05 to 0.4 pts.mass of a nucleating agent relative to a total of 100 pts.mass of (A) and (B), and satisfying a requirement (C1). Details of (A2) to (A4) and (C1) are shown in the specification: (A1) the melt flow rate (MFR) is 0.4-2.0 g / 10 min. as measured according to JIS K 7210 at 230°C and under a load of 2.16 kg; (B1) the melt flow rate (MFR) is 5.0-80 g / 10 min. as measured according to JIS K 7210 at 230°C and under a load of 2.16 kg; and (B2) the density is 930-955 kg / m3.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polypropylene resin composition and a molded article. [Background technology]

[0002] As raw materials for blow molded articles such as blown containers, resins such as vinyl chloride resin, polycarbonate resin, ethylene-based resin, and propylene-based resin are used depending on the application. Among these resins, polyethylene resin is widely used as a material that is inexpensive and has excellent moldability. However, when a hard ethylene-based resin such as high-density polyethylene is used, there are problems in that gloss and transparency are poor, and when a soft ethylene-based resin such as low-density polyethylene is used, rigidity is low.

[0003] On the other hand, when propylene-based resins are used, the resulting blow-molded articles have relatively low production costs, similar to polyethylene-based resins, and are superior in gloss and transparency to high-density polyethylene, and are therefore used as containers for liquid detergents, cosmetics, food, medicines, etc.

[0004] For example, Patent Document 1 discloses a propylene-based resin composition for blow molding that has good moldability and is excellent in impact strength, transparency, and heat distortion resistance, the propylene-based resin composition containing 65 to 85 wt % of a propylene-ethylene random copolymer (A) satisfying requirements (Ai) to (A-iii) and 15 to 35 wt % of an ethylene-α-olefin random copolymer (B) satisfying requirements (Bi) to (B-iii), based on the total weight of the composition, and that is substantially free of a crystallization nucleating agent and capable of being blow molded. (Ai) The melt flow rate measured under the conditions of a temperature of 230°C and a load of 2.16 kg is 0.1 to 20 g / 10 min. (A-ii) The ethylene content is 1 to 6% by weight. (A-iii) The maximum crystal melting peak temperature observed in the range of 50 to 180°C in differential scanning calorimetry is 135°C or higher. (Bi) An ethylene-α-olefin random copolymer polymerized with a metallocene catalyst. (B-ii) The melt flow rate measured under conditions of a temperature of 230°C and a load of 2.16 kg is 0.1 to 20 g / 10 min. (B-iii) Density: 0.899 to 0.920 g / cm 3 That is. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-119814 Summary of the Invention [Problem to be solved by the invention]

[0006] Recently, propylene-based resin compositions have been increasingly used not only for sanitary and toiletry products but also for food applications due to their excellent impact strength and transparency. In particular, the airtightness of bottle containers and caps for liquid food applications has become important, and there is a demand for improved cuttability of the bottle neck to ensure airtightness. Conventionally, propylene-based resins have been inferior to polyethylene-based resins in machinability and burr cutting (removal of unnecessary parts), and therefore there is a demand for improved machinability in molded articles formed from propylene-based resin compositions. Poor machinability means that product production stability and yield will deteriorate due to poor burr cutting, poor cutting performance will result in poor food hygiene due to insufficient sealing between the bottle mouth and cap, and there is also the risk that poorly cut pieces will fall into the bottle and become foreign matter in the food, thereby compromising food safety. Patent Document 1 discloses a method of blending low-density PE (polyethylene) into a direct-blow molding material made from a propylene-based resin composition to improve transparency and impact resistance. While this method improves bottle performance, it tends to make the bottle neck less easy to cut.

[0007] An object of one embodiment of the present invention is to provide a propylene-based resin composition that produces a molded article having excellent transparency, impact resistance, and machinability. Another problem to be solved by another embodiment of the present invention is to provide a molded article that is excellent in transparency, impact resistance, and machinability. [Means for solving the problem]

[0008] The means for solving the above problems include the following aspects. <1> A propylene-based resin composition comprising: 87 to 97 parts by mass of a propylene-based polymer (A) satisfying the following requirements (A1) to (A4); 3 to 13 parts by mass of an ethylene-α-olefin copolymer (B) satisfying the following requirements (B1) to (B2) (wherein the total of the propylene-based polymer (A) and the ethylene-α-olefin copolymer (B) is 100 parts by mass); and 0.05 to 0.4 parts by mass of a nucleating agent (C) that satisfies the following requirement (C1) and is based on 100 parts by mass of the propylene-based polymer (A) and the ethylene-α-olefin copolymer (B). (A1): Melt flow rate (MFR) of 0.4 to 2.0 g / 10 min, measured at 230°C under a load of 2.16 kg in accordance with JIS K 7210 (A2): The portion insoluble in n-decane at room temperature (Dinsol) is 80 to 90 mass %, and the portion soluble in n-decane at room temperature (Dsol) is 10 to 20 mass % (where the total of Dinsol and Dsol is 100 mass %) (A3): The content of ethylene-derived structural units in the n-decane-insoluble portion (Dinsol) at room temperature is 0.1 to 1.5% by mass. (A4): The content of ethylene-derived structural units in the n-decane soluble portion (Dsol) at room temperature is 20 to 40% by mass. (B1): Melt flow rate (MFR) of 5.0 to 80 / 10 min, measured at 230°C under a load of 2.16 kg in accordance with JIS K 7210 (B2): Density 930-955 kg / m 3 (C1): The ratio (B1) / (A1) of the melt flow rate (MFR) of the ethylene-α-olefin copolymer (B) to the melt flow rate (MFR) of the propylene-based resin composition (A) is 12.5 to 62.5. <2> <1> A blow-molded article comprising the propylene-based resin composition according to claim 1. <3> <1> An injection blow molded article comprising the propylene-based resin composition according to claim 1. <4> It is a container <2> or <3> The molded article according to claim 1. <5> It is a food container <4> The molded article according to claim 1. [Effects of the Invention]

[0009] According to one embodiment of the present invention, there is provided a propylene-based resin composition which produces a molded article having excellent transparency, impact resistance, and machinability. According to another embodiment of the present invention, a molded article having excellent transparency, impact resistance, and machinability is provided. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below. The following description of the components may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In this specification, the use of "to" to indicate a range of values ​​means that the values ​​before and after it are included as the lower and upper limits. In this specification, when a numerical range is indicated by "to", the units written before or after the range indicate the same units unless otherwise specified. As used herein, a combination of two or more preferred embodiments is a more preferred embodiment. The present invention will be described in detail below.

[0011] (Propylene-based resin composition) The propylene-based resin composition according to the present invention contains 87 to 97 parts by mass of a propylene-based polymer (A) satisfying the following requirements (A1) to (A4), 3 to 13 parts by mass of an ethylene-α-olefin copolymer (B) satisfying the following requirements (B1) and (B2) (where the total of the propylene-based polymer (A) and the ethylene-α-olefin copolymer (B) is 100 parts by mass), and 0.05 to 0.4 parts by mass of a nucleating agent that satisfies the following requirement (C1) and is based on 100 parts by mass of the total of (A) and (B). (A1): Melt flow rate (MFR) of 0.4 to 2.0 g / 10 min, measured at 230°C under a load of 2.16 kg in accordance with JIS K 7210 (A2): The propylene polymer (A) has a portion (Dinsol) insoluble in n-decane at room temperature of 80 to 90 mass % and a portion (Dsol) soluble in n-decane at room temperature of 10 to 20 mass % (where the total of Dinsol and Dsol is 100 mass %). (A3): The content of structural units derived from ethylene in the Dinsol is 0.1 to 1.5% by mass. (A4): The content of structural units derived from ethylene in the Dsol is 20 to 40% by mass. (B1): Melt flow rate (MFR) of 5.0 to 80 / 10 min, measured at 230°C under a load of 2.16 kg in accordance with JIS K 7210 (B2): Density 930-955 kg / m 3 is (C1): The ratio (B1) / (A1) of the melt flow rate (MFR) of the ethylene-α-olefin copolymer (B) to the melt flow rate (MFR) of the ethylene-α-olefin copolymer (B) / propylene-based resin composition (A) is 12.5 to 62.5.

[0012] As mentioned above, in order to improve impact resistance and transparency, for example, in a direct blow molding material of a propylene-based resin composition described in Patent Document 1, the density is 930 kg / m 3In many cases, the propylene-based resin composition contains less than 100% ethylene-α-olefin copolymer (B), and containers formed from such propylene-based resin compositions have poor bottle neck cuttability and burr cuttability, making them unsuitable for use as molded articles for food applications. The inventors have conducted extensive research and found that the propylene-based resin composition according to the present invention, which has the above-mentioned structure, provides a molded article with excellent transparency, impact resistance, and machinability. The reason for this is unclear, but is presumed to be as follows. It is presumed that the ethylene-α-olefin copolymer (B) having a density and melt flow rate (MFR) within specific ranges and the propylene-based polymer (A) having physical property values ​​within specific ranges are contained in specific amounts, which facilitates dispersion of the ethylene-α-olefin copolymer (B) to the propylene-based polymer (A) to a specific intended particle size, resulting in a molded article with an excellent balance of transparency, impact resistance, and machinability.

[0013] <Propylene polymer (A)> The propylene polymer (A) satisfies the requirements (A1) to (A4). The propylene polymer (A) is not particularly limited as long as it satisfies the requirements (A1) to (A4), and is preferably a copolymer of propylene and an α-olefin (excluding propylene), and more preferably a propylene block copolymer containing a component consisting of structural units derived from propylene and a component consisting of structural units derived from propylene and ethylene. The copolymer of propylene and an α-olefin (excluding propylene) may be a block copolymer or a random copolymer.

[0014] Examples of the α-olefin (excluding propylene) include ethylene and α-olefins having 4 to 20 carbon atoms, and among these, ethylene and α-olefins having 4 to 10 carbon atoms are preferred.

[0015] The propylene polymer (A) preferably contains 80 to 100 mol % of structural units derived from propylene and 0.1 to 20 mol % of structural units derived from α-olefins, and more preferably contains 90 to 100 mol % of structural units derived from propylene and 0.1 to 10 mol % of structural units derived from α-olefins, relative to 100 mol % of structural units derived from all monomers constituting the propylene polymer (A).

[0016] <<Requirement (A1)>> (A1): The melt flow rate (MFR), measured in accordance with JIS K 7210 at 230°C under a load of 2.16 kg, is 0.4 to 2.0 g / 10 min, preferably 0.5 to 1.5 g / 10 min, and more preferably 0.5 to 1.0 g / 10 min. When the MFR of the propylene polymer (A) is within the above range, the resulting molded article has excellent blow moldability and machinability.

[0017] <<Requirements (A2)>> (A2): The propylene polymer (A) has a n-decane insoluble portion (Dinsol) of 80 to 90% by mass, preferably 82 to 88% by mass, and more preferably 84 to 88% by mass, and a n-decane soluble portion (Dsol) of 10 to 20% by mass, preferably 12 to 18% by mass, and more preferably 13 to 16% by mass at room temperature (where the total of Dinsol and Dsol is 100% by mass). Specifically, room temperature is 23°C.

[0018] In the propylene polymer (A), the n-decane-insoluble portion (Dinsol) is usually a component mainly composed of structural units derived from propylene, and is thought to have crystallinity and exhibit high rigidity. The n-decane-soluble portion (Dsol) is usually a component mainly composed of structural units derived from propylene and α-olefins (excluding propylene). The Dsol component is a component that does not exhibit crystallinity or has low crystallinity, and is thought to have a low glass transition temperature, impact resistance, and compatibility with the ethylene-α-olefin copolymer (B), which will be described later. The n-decane soluble portion (Dsol) is sometimes referred to as the rubber component. The propylene polymer (A) is usually a propylene copolymer (so-called block copolymer) having an n-decane insoluble portion (Dinsol) and an n-decane soluble portion (Dsol).

[0019] When the contents of Dsol and Dinsol are within the above ranges, the content of Dsol in the propylene polymer (A) is ensured to a certain extent, and therefore the absorbed energy against impact is improved, and the obtained molded article tends to have excellent impact resistance, high-speed moldability, and rigidity (buckling strength).

[0020] As described in the Examples below, the "portion (Dsol) soluble in n-decane at room temperature" refers to a component of the propylene polymer (A) that is dissolved in the n-decane solution when the temperature is lowered to 23°C after heating and dissolving in n-decane at 150°C for 2 hours.

[0021] Specifically, the "portion soluble in n-decane at room temperature (Dsol)" and the "portion insoluble in n-decane at room temperature (Dinsol)" are determined by the following method. First, approximately 3 g of propylene polymer (A), 500 mL of decane, and a small amount of a heat stabilizer soluble in decane were placed in a glass measuring vessel. The vessel was heated to 150°C over 2 hours while stirring with a stirrer under a nitrogen atmosphere to dissolve the propylene polymer (A). The vessel was then maintained at 150°C for 2 hours and then slowly cooled to 23°C over 8 hours. The resulting liquid containing a precipitate of the propylene polymer (A) was filtered under reduced pressure using a 25G-4 glass filter manufactured by Iwata Glass Co., Ltd. The components dissolved in the filtrate were identified as the portion soluble in n-decane at 23°C (Dsol). The precipitate remaining on the glass filter was identified as the portion insoluble in n-decane at 23°C (Dinsol), which was identified as a structural unit derived from α-olefins (excluding propylene).

[0022] <<Requirements (A3)>> (A3): The content of structural units derived from ethylene in Dinsol is 0.1 to 1.5 mass%, preferably 0.1 to 1.0 mass%, and more preferably 0.3 to 0.8 mass%. When the content of structural units derived from ethylene in Dinsol is within the above range, the transparency of the obtained molded article is excellent, and this contributes to the compatibility and dispersibility with the Dsol components and the ethylene-α-olefin copolymer (B).

[0023] <<Requirements (A4)>> (A4): The content of structural units derived from ethylene in the Dsol is 20 to 40% by mass, preferably 20 to 35% by mass, and more preferably 25 to 30% by mass. By setting the content of ethylene-derived structural units in the portion (Dsol) of the propylene polymer (A) soluble in n-decane at room temperature within the above range, the transparency of the obtained molded article is less likely to decrease, and the decrease in impact resistance is also suppressed, resulting in an excellent balance between transparency and impact resistance.

[0024] [Intrinsic viscosity [η] of Dsol in tetralin at 135°C] The propylene polymer (A) has an intrinsic viscosity [ηsol] of preferably 1.8 to 3.5 dl / g, more preferably 2.0 to 2.8 dl / g, in tetralin at 135° C., in the portion (Dinsol) insoluble in n-decane at room temperature. When the intrinsic viscosity [ηsol] is within the above range, the obtained molded article has excellent impact resistance. The intrinsic viscosity [ηsol] can be determined by the measurement method employed in the examples described below.

[0025] <<Propylene polymer (A) content>> The content of the propylene polymer (A) is 87 to 97 parts by mass, preferably 87 to 96% by mass, and more preferably 87 to 95% by mass (where the total of the propylene polymer (A) and the ethylene-α-olefin copolymer (B) is 100 parts by mass). The propylene polymer (A) may be used alone or in combination of two or more kinds.

[0026] The propylene polymer (A) is not particularly limited in its production method, and is usually obtained by copolymerizing propylene and ethylene in the presence of a metallocene compound-containing catalyst or a Ziegler-Natta catalyst.

[0027] The propylene polymer (A) is preferably obtained by copolymerizing propylene and ethylene in the presence of a Ziegler-Natta catalyst, since this makes it easier to obtain a resin with a wide molecular weight distribution and good moldability.

[0028] [Metallocene compound-containing catalyst] Examples of metallocene compound-containing catalysts include metallocene catalysts composed of a metallocene compound and at least one compound selected from organometallic compounds, organoaluminum oxy compounds, and compounds capable of reacting with the metallocene compound to form an ion pair, and optionally a particulate support. Metallocene catalysts capable of stereoregular polymerization, such as isotactic or syndiotactic structures, are preferred. Among these metallocene compounds, preferred are the crosslinked metallocene compounds exemplified in International Publication No. 2001 / 27124 and the metallocene compounds described in paragraphs

[0068] to

[0076] of International Publication No. 2010 / 74001. Furthermore, compounds capable of reacting with organometallic compounds, organoaluminum oxy compounds, and transition metal compounds to form ion pairs, as well as optional particulate supports, include, without limitation, compounds disclosed in International Publication No. 2001 / 27124, Japanese Patent Application Laid-Open No. 11-315109, and the like.

[0029] [Ziegler-Natta catalyst] The propylene polymer (A) can be produced using a highly stereoregular Ziegler-Natta catalyst. Various known catalysts can be used as the highly stereoregular Ziegler-Natta catalyst. For example, a catalyst can be used that comprises (a) a solid titanium catalyst component containing magnesium, titanium, a halogen, and an electron donor, (b) an organometallic compound catalyst component, and (c) an organosilicon compound catalyst component having at least one group selected from the group consisting of a cyclopentyl group, a cyclopentenyl group, a cyclopentadienyl group, and derivatives thereof. This catalyst component can be produced by a known method, such as the method described in paragraphs

[0078] to

[0094] of WO 2010 / 74001.

[0030] When polymerizing propylene using a catalyst comprising the above-mentioned solid titanium catalyst component (a), organometallic compound catalyst component (b), and organosilicon compound catalyst component (c), prepolymerization can also be carried out in advance. In prepolymerization, olefins are polymerized in the presence of the solid titanium catalyst component (a), organometallic compound catalyst component (b), and, if necessary, organosilicon compound catalyst component (c).

[0031] The olefin to be prepolymerized can be an α-olefin having 2 to 8 carbon atoms. Specifically, linear olefins such as ethylene, propylene, 1-butene, and 1-octene; olefins having a branched structure such as 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, and 3-ethyl-1-hexene can be used. These olefins may be copolymerized.

[0032] The prepolymerization is desirably carried out so that about 0.1 to 1000 g, preferably about 0.3 to 500 g, of polymer is produced per gram of the solid titanium catalyst component (a). If the amount of prepolymerization is too large, the efficiency of (co)polymer production in the main polymerization may decrease. In the prepolymerization, the catalyst can be used at a concentration significantly higher than the catalyst concentration in the system in the main polymerization.

[0033] In the main polymerization, the solid titanium catalyst component (a) (or prepolymerization catalyst) is preferably used in an amount of about 0.0001 to 50 millimoles, preferably about 0.001 to 10 millimoles, calculated as titanium atoms per liter of polymerization volume. The organometallic compound catalyst component (b) is preferably used in an amount of about 1 to 2,000 moles, preferably about 2 to 500 moles, calculated as metal atoms, per mole of titanium atoms in the polymerization system. The organosilicon compound catalyst component (c) is preferably used in an amount of about 0.001 to 50 moles, preferably about 0.01 to 20 moles, per mole of metal atoms in the organometallic compound catalyst component (b).

[0034] [Method for producing propylene polymer (A)] The propylene polymer (A) is preferably produced by copolymerizing propylene and ethylene in the presence of the above-mentioned metallocene compound-containing catalyst or Ziegler-Natta catalyst.

[0035] When the propylene polymer (A) is produced by continuous multi-stage polymerization, it is preferable to homopolymerize propylene or copolymerize propylene and ethylene in each stage. The polymerization method is not particularly limited, and may be, for example, a gas phase polymerization method or a liquid phase polymerization method such as a solution polymerization method or a suspension polymerization method, and each stage may be carried out by a separate method. Furthermore, either a continuous or semi-continuous method may be used, and each stage may be carried out separately in a plurality of polymerization vessels, for example, 2 to 10 polymerization vessels. From an industrial perspective, polymerization by a continuous method is preferred, and in this case, the second and subsequent stages of polymerization are preferably carried out separately in two or more polymerization vessels, which can prevent the formation of gel in the polymer.

[0036] The polymerization medium may be an inert hydrocarbon, or liquid propylene may be used. The polymerization conditions for each stage are appropriately selected from the range of polymerization temperature from about -50 to +200°C, preferably about 20 to 100°C, and polymerization pressure from normal pressure to 10 MPa (gauge pressure), preferably about 0.2 to 5 MPa (gauge pressure).

[0037] The propylene polymer (A) can be produced, for example, by continuously carrying out the following two steps ([Step 1] and [Step 2]) in a reactor having two or more polymerization vessels connected in series to obtain the propylene polymer (A). In this case, [Step 1] may be carried out in each polymerization vessel using a polymerization vessel having two or more reactors connected in series, or [Step 2] may be carried out in each polymerization vessel using a polymerization vessel having two or more reactors connected in series. Alternatively, [Step 1] and [Step 2] may be carried out separately, and the polymers obtained in each step may be melt-kneaded using a single-screw extruder, a multi-screw extruder, a kneader, a Banbury mixer, or the like to produce the propylene polymer (A).

[0038] The method for producing the propylene polymer (A) by successively carrying out [Step 1] and [Step 2] will be described below. [Step 1] is a step of polymerizing propylene and optionally ethylene at a polymerization temperature of 0 to 100°C and a polymerization pressure of normal pressure to 5 MPa gauge pressure, in which a propylene-based polymer, which is the main component of Dinsol, is produced by supplying no ethylene or a small amount of ethylene compared to the amount of propylene fed. If necessary, a chain transfer agent such as hydrogen gas may be introduced to adjust the intrinsic viscosity [η] of the polymer produced in [Step 1].

[0039] [Step 2] is a step in which propylene and ethylene are copolymerized at a polymerization temperature of 0 to 100°C and at a polymerization pressure of normal pressure to 5 MPa gauge pressure, and is a step in which the main component of Dsol (rubber component) is produced by increasing the ratio of the amount of ethylene fed to the amount of propylene fed compared to that in [Step 1]. If necessary, a chain transfer agent such as hydrogen gas may also be introduced to adjust the intrinsic viscosity [η] of the polymer produced in [Step 2].

[0040] The propylene polymer (A) can be obtained by continuously carrying out the above [Step 1] and [Step 2], and the requirements (A1) to (A4) can be adjusted as follows. The MFR in requirement (A1) can be adjusted by adjusting the ratio of the feed amount of hydrogen gas as a chain transfer agent to the feed amount of monomer (i.e., propylene in the case of propylene homopolymerization, or propylene and ethylene in the case of copolymerization) when performing [Step 1] or [Step 2]. That is, by increasing this ratio, the MFR can be increased, and by decreasing this ratio, the MFR can be decreased.

[0041] In addition to the above-mentioned methods, the MFR can also be adjusted by melt-kneading the propylene polymer obtained by polymerization in the presence of an organic peroxide. The MFR increases when the propylene polymer obtained by polymerization is melt-kneaded in the presence of an organic peroxide, and the MFR increases further when the amount of organic peroxide added during the melt-kneading in the presence of the organic peroxide is increased. When the propylene polymer obtained by polymerization is melt-kneaded in the presence of an organic peroxide, the amount of the organic peroxide added is preferably 0.005 to 0.05 parts by mass per 100 parts by mass of the propylene polymer (A). The melt-kneading in the presence of the organic peroxide may be carried out after the post-treatment step described below. The organic peroxide is not particularly limited, and examples thereof include conventionally known organic peroxides, such as 2,5-dimethyl-2,5-di(benzoylperoxy)hexane and 1,3-bis(t-butylperoxyisopropyl)benzene.

[0042] The content of Dinsol and the content of Dsol in requirement (A2) can be adjusted by adjusting the polymerization times in the above [Step 1] and [Step 2]. In other words, by increasing the proportion of the polymerization time in [Step 1] relative to the total polymerization time, the proportion of Dinsol can be increased and the proportion of Dsol can be decreased. Also, by increasing the proportion of the polymerization time in [Step 2] relative to the total polymerization time, the proportion of Dinsol can be decreased and the proportion of Dsol can be increased.

[0043] The content of ethylene-derived structural units in Dinsol in requirement (A3) can be adjusted by adjusting the ratio of the amount of ethylene fed to the amount of propylene fed when carrying out [Step 1]. That is, by increasing the ratio of this feed amount, the proportion of ethylene-derived structural units can be increased, and by decreasing the ratio of this feed amount, the proportion of ethylene-derived structural units can be decreased.

[0044] The proportion of ethylene-derived structural units in the Dsol in requirement (A4) can be adjusted by adjusting the ratio of the amount of ethylene fed to the amount of propylene fed when performing [Step 2]. That is, by increasing the ratio of this feed amount, the proportion of ethylene-derived structural units can be increased, and by decreasing the ratio of this feed amount, the proportion of ethylene-derived structural units can be decreased.

[0045] The intrinsic viscosity [ηsol] can be adjusted by the amount of hydrogen gas fed as a chain transfer agent in Step 2. That is, the intrinsic viscosity [ηsol] can be reduced by increasing the ratio of the amount of hydrogen gas fed to the amount of monomers (i.e., propylene and ethylene), and the intrinsic viscosity [ηsol] can be increased by decreasing the ratio of the amount of hydrogen gas fed to the amount of monomers fed.

[0046] After the polymerization is completed, known post-treatment steps such as a catalyst deactivation step, a catalyst residue removal step, and a drying step are carried out as needed, to obtain the propylene polymer (A) as a powder. Furthermore, commercially available products may be used as the propylene polymer (A).

[0047] <Ethylene-α-olefin copolymer (B)> The ethylene-α-olefin copolymer (B) satisfies the following requirements (B1) and (B2). The ethylene-α-olefin copolymer (B) is not particularly limited as long as it satisfies the requirements (B1) and (B2), and preferably contains, for example, structural units derived from ethylene and structural units derived from an α-olefin having 3 to 20 carbon atoms, as this provides excellent impact resistance and transparency. The copolymer may be a block copolymer or a random copolymer.

[0048] Examples of α-olefins having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, etc. Among these, α-olefins having 4 to 10 carbon atoms are preferred from the viewpoints of transparency, impact resistance, rigidity, and economy.

[0049] In the ethylene-α-olefin copolymer (B), the constituent units derived from ethylene preferably account for 80 to 99 mol % and the constituent units derived from α-olefins preferably account for 1 to 20 mol %, and more preferably the constituent units derived from ethylene preferably account for 90 to 99 mol % and the constituent units derived from α-olefins preferably account for 1 to 10 mol %, relative to 100 mol % of the constituent units derived from all monomers constituting the ethylene-α-olefin copolymer (B).

[0050] <<Requirement (B1)>> (B1): The melt flow rate (MFR), measured in accordance with JIS K 7210 at 230°C under a load of 2.16 kg, is 5.0 to 80 / 10 minutes, preferably 10 to 70 / 10 minutes, more preferably 20 to 60 / 10 minutes, and even more preferably 30 to 50 / 10 minutes. When the MFR of the ethylene-α-olefin copolymer (B) is within the above range, the dispersion shape of the ethylene-α-olefin copolymer (B) in the propylene-based resin composition is controlled, thereby improving the absorption energy against impact and providing the obtained molded article with excellent impact resistance.

[0051] <<Requirements (B2)>> The density of the ethylene-α-olefin copolymer (B) is 930 to 955 kg / m 3 and preferably 930 to 950 kg / m 3 and more preferably 935 to 945 kg / m 3 is. When the density of the ethylene-α-olefin copolymer (B) is within the above range, the resulting molded article has excellent transparency, impact resistance and machinability.

[0052] The density value of ethylene-α-olefin copolymer (B) was measured by the density gradient tube method using a sample obtained by heat-treating a strand obtained during the MFR measurement of ethylene-α-olefin copolymer (B) at 120°C for 1 hour and then slowly cooling to room temperature over 1 hour.

[0053] The content of the ethylene-α-olefin copolymer (B) is 3 to 13 parts by mass, preferably 5 to 13 parts by mass, and more preferably 6 to 12 parts by mass (where the total of the propylene polymer (A) and the ethylene-α-olefin copolymer (B) is 100 parts by mass).

[0054] The ethylene-α-olefin copolymer (B) can be produced by a conventionally known method. The MFR in requirement (B1) can be adjusted by adjusting the ratio of the amount of hydrogen gas fed as a chain transfer agent to the amount of monomer (i.e., ethylene and α-olefin) fed when ethylene and α-olefin are copolymerized to produce ethylene-α-olefin copolymer (B). That is, by increasing this ratio, the MFR can be increased, and by decreasing this ratio, the MFR can be decreased.

[0055] The density in requirement (B2) can be adjusted by adjusting the ratio of the amount of α-olefin fed to the amount of ethylene fed when ethylene and α-olefin are copolymerized to produce ethylene-α-olefin copolymer (B). In other words, by increasing this ratio, the density can be lowered, and by decreasing this ratio, the density can be increased.

[0056] The ethylene-α-olefin copolymer (B) may be obtained by polymerization, or a commercially available product may be used. An example of a commercially available product is Neozex (registered trademark) 45200 (MFR=20 g / 10 min, density=943 kg / m 3 ), Neozex (registered trademark) 40300J (MFR = 40 g / 10 min, density = 938 kg / m 3 ) (all manufactured by Prime Polymer Co., Ltd.).

[0057] <Nucleating Agent (C)> The propylene-based resin composition according to the present invention contains a nucleating agent (C). By including the nucleating agent (C), the propylene-based resin composition provides excellent rigidity to molded articles such as containers formed from the propylene-based resin composition. This is presumably due to the increased rigidity resulting from the improved crystallinity. The nucleating agent is not particularly limited, but examples thereof include sorbitol-based nucleating agents, nonitol-based nucleating agents, phosphorus-based nucleating agents, metal carboxylate-based nucleating agents, polymer nucleating agents, and inorganic compounds.

[0058] Specific examples of sorbitol-based nucleating agents include 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol, 1,3,2,4-dibenzylidene sorbitol, 1,3,2,4-di-(p-methylbenzylidene) sorbitol, and 1,3-p-chlorobenzylidene-2,4-p-methylbenzylidene sorbitol.

[0059] Furthermore, examples of nonitol-based nucleating agents include commercially available products containing 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol, such as the "Milad NX8000" series manufactured by Milliken. "Milad NX8000" contains 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol, a fluorescent whitening agent, and a blooming agent, while "Milad NX8000K" does not contain the fluorescent whitening agent contained in "Milad NX8000," and "Milad NX8000J" does not contain the fluorescent whitening agent and blooming agent contained in "Milad NX8000."

[0060] Specific examples of phosphorus-based nucleating agents include sodium bis-(4-t-butylphenyl) phosphate, potassium bis-(4-t-butylphenyl) phosphate, sodium 2,2'-ethylidene-bis(4,6-di-t-butylphenyl) phosphate, sodium 2,2'-methylene-bis(4,6-di-t-butylphenyl) phosphate, and bis(2,4,8,10-tetra-t-butyl-6-hydroxy-12H-dibenzo[d,g][1,3,2]dioxaphosphocin-6-oxide) sodium salt (trade name "ADK STAB (registered trademark)"). Examples of such a composite include "ADK STAB NA-11" (manufactured by ADEKA CORPORATION), a composite containing bis(2,4,8,10-tetra-t-butyl-6-hydroxy-12H-dibenzo[d,g][1,3,2]dioxaphosphocin-6-oxide) aluminum hydroxide salt as the main component (trade name "ADK STAB NA-21" (manufactured by ADEKA CORPORATION), and a composite containing lithium-2,2'-methylene-bis(4,6-di-t-butylphenyl)phosphate and 12-hydroxystearic acid, and containing lithium as an essential component (trade name "ADK STAB NA-71" (manufactured by ADEKA CORPORATION).

[0061] Specific examples of metal carboxylate nucleating agents include aluminum pt-butylbenzoate, aluminum hydroxy-di(pt-butylbenzoate) (trade name "AL-PTBBA", manufactured by Japan Chemtech), aluminum adipate, and sodium benzoate.

[0062] Suitable examples of the polymer nucleating agent include branched α-olefin polymers other than the above-mentioned propylene polymer (A) and ethylene-α-olefin copolymer (B). Examples of branched α-olefin polymers include homopolymers of 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, and 3-ethyl-1-hexene, as well as copolymers thereof with other α-olefins. From the viewpoints of low-temperature impact resistance, good rigidity, and economy, 3-methyl-1-butene polymers are particularly preferred.

[0063] Specific examples of inorganic compounds include talc, mica, and calcium carbonate. Among these nucleating agents, bis(2,4,8,10-tetra-t-butyl-6-hydroxy-12H-dibenzo[d,g][1,3,2]dioxaphosphocin-6-oxide) sodium salt, 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propyphenyl)methylene]-nonitol, and aluminum hydroxy-di(pt-butylbenzoate) are preferred. Among these, sorbitol-based nucleating agents, nonitol-based nucleating agents, phosphorus-based nucleating agents, and polymer nucleating agents are preferred as nucleating agents.

[0064] The propylene-based resin composition contains 0.05 to 0.4 parts by mass, preferably 0.1 to 0.3 parts by mass, and more preferably 0.15 to 0.25 parts by mass of a nucleating agent per 100 parts by mass of the total of (A) and (B). The nucleating agent may be used alone or in combination of two or more kinds. When the content of the nucleating agent is within the above range, the effect of improving rigidity is easily obtained, and the obtained molded article has excellent impact resistance.

[0065] The propylene-based resin composition according to the present invention may contain appropriate components other than the propylene-based polymer (A), the ethylene-α-olefin copolymer (B), and the nucleating agent (C) (hereinafter, also referred to as "other components"), provided that the addition does not impair the object of the present invention. Other components include additives such as neutralizing agents, antioxidants, heat stabilizers, weathering agents, lubricants, ultraviolet absorbers, antistatic agents, antiblocking agents, antifogging agents, anti-bubbling agents, dispersants, flame retardants, antibacterial agents, fluorescent brightening agents, crosslinking agents, and crosslinking aids; and colorants such as dyes and pigments.

[0066] <<Requirement (C1)>> The propylene-based resin composition according to the present invention satisfies the requirement (C1). (C1) The ratio (B1) / (A1) of the melt flow rate (MFR) of the ethylene-α-olefin copolymer (B) to the melt flow rate (MFR) of the propylene-based resin composition (A) is 12.5 to 62.5, preferably 15.0 to 55.0, more preferably 18.0 to 50.0, and even more preferably 20.0 to 48.0. When the (B1) / (A1) ratio in the propylene-based resin composition (A) is within the above range, the resulting molded article has excellent transparency, impact resistance, and machinability.

[0067] The propylene-based resin composition according to the present invention contains 87 to 97 parts by mass of the propylene-based polymer (A), 3 to 13 parts by mass of the ethylene-α-olefin copolymer (B), and 0.05 to 0.4 parts by mass of the nucleating agent (C), preferably 87 to 96 parts by mass of the propylene-based polymer (A), 5 to 13 parts by mass of the ethylene-α-olefin copolymer (B), and 0.1 to 0.3 parts by mass of the nucleating agent (C), and more preferably 87 to 95 parts by mass of the propylene-based polymer (A), 6 to 12 parts by mass of the ethylene-α-olefin copolymer (B), and 0.15 to 0.25 parts by mass of the nucleating agent (C) (where the total of the propylene-based polymer (A) and the ethylene-α-olefin copolymer (B) is 100 parts by mass).

[0068] The melt flow rate (MFR) of the propylene resin composition according to the present invention can be adjusted by appropriately selecting the melt flow rate of the propylene polymer (A) or the melt flow rate of the ethylene-α-olefin copolymer (B), or by adjusting the blending ratio of the propylene polymer (A) and the ethylene-α-olefin copolymer (B).

[0069] The MFR of the propylene-based resin composition according to the present invention can also be adjusted by adding an organic peroxide to each component when the components are melt-kneaded in a kneader. That is, the MFR of the propylene-based resin composition can be increased by adding an organic peroxide when melt-kneading or by increasing the amount of organic peroxide added when melt-kneading.

[0070] The organic peroxide is not particularly limited, but examples thereof include conventionally known organic peroxides such as 2,5-dimethyl-2,5-di-(benzoylperoxy)hexane and 1,3-bis-(t-butylperoxyisopropyl)benzene. When an organic peroxide is used, it is preferable to use 0.005 to 0.05 part by mass of the organic peroxide per 100 parts by mass of the total of the propylene polymer (A) and the ethylene-α-olefin copolymer (B).

[0071] The propylene-based resin composition according to the present invention has a so-called sea-island structure in which Dinsol is mainly the continuous phase, ie, the sea portion, and Dsol and the ethylene-α-olefin copolymer (B) are mainly the island portions.

[0072] The method for producing the propylene-based resin composition is not particularly limited, but for example, the propylene-based resin composition may be produced by melt-kneading the above-mentioned components in a kneader. Examples of kneaders include single-screw kneading extruders, multi-screw kneading extruders, kneaders, Banbury mixers, and Henschel mixers. The melt-kneading conditions are not particularly limited as long as the molten resin is not deteriorated by shear during kneading, heating temperature, heat generated by shear, etc. From the viewpoint of preventing deterioration of the molten resin, it is effective to appropriately set the heating temperature and add an antioxidant or a heat stabilizer.

[0073] <Molded body> The molded article according to the present invention includes the propylene-based resin composition according to the present invention described above. Suitable examples of the molded article include a blow-molded article including the propylene-based resin composition according to the present invention, and an injection-blow-molded article including the propylene-based resin composition according to the present invention.

[0074] Examples of molded articles include containers, home appliance parts, and daily necessities. Among these, containers are preferred in terms of transparency, impact resistance, and rigidity. Examples of such containers include packaging containers for liquid daily necessities such as hair wash, hair conditioner, cosmetics, detergent, and disinfectant; food containers for liquids such as soft drinks, water, and seasonings; food containers (dessert cups) for solids such as jelly, pudding, and yogurt; soy sauce containers, sauce containers, and salad oil containers; Other packaging containers for chemicals; packaging containers for industrial liquids, etc.

[0075] The molded article has a good balance of transparency and impact resistance, and is therefore suitable for use as a food container among these containers.

[0076] The method for producing a molded article preferably includes a step of molding the propylene-based resin composition of the present invention. As a molding method for a molded article, a direct blow molding method is preferably used. In the direct blow molding method, for example, the propylene-based resin composition is introduced into the hopper of a direct blow molding machine, the resin is fed into a cylinder heated to approximately 180°C to 250°C, kneaded and plasticized to a molten state, and a cylindrical molten parison is molded using a crosshead die. The parison is then sandwiched between blow molds whose temperature is controlled to 5 to 60°C using cooling water or hot water in a water circulation circuit, and the mixture is blown at a pressure of 2.0 to 10.0 kg / cm. 2 Compressed air adjusted to a temperature of 100°C is blown into the parison, causing it to stretch and adhere to the mold, and then the parison is cooled and solidified to obtain a cylindrical blown container. [Example]

[0077] The present invention will be further described below with reference to examples, although the present invention is not limited to these examples.

[0078] The following polymers were used as the polymers contained in the propylene-based resin compositions used in the Examples and Comparative Examples. [Production of Propylene Polymer (A-1)] (1) Preparation of solid catalyst component 95.2 g of anhydrous magnesium chloride, 442 mL of decane, and 390.6 g of 2-ethylhexyl alcohol were subjected to a heating reaction at 130°C for 2 hours to obtain a homogeneous solution, and then 21.3 g of phthalic anhydride was added to this solution, followed by stirring and mixing at 130°C for an additional 1 hour to dissolve the phthalic anhydride. The homogeneous solution thus obtained was cooled to room temperature, and then 75 mL of this homogeneous solution was added dropwise over 1 hour to 200 mL of titanium tetrachloride maintained at -20°C. After the addition was complete, the temperature of this mixture was raised to 110°C over 4 hours, and when it reached 110°C, 5.22 g of diisobutyl phthalate (DIBP) was added, and the mixture was stirred at the same temperature for another 2 hours. After the 2-hour reaction, the solid was collected by hot filtration, resuspended in 275 mL of titanium tetrachloride, and heated again for 2 hours at 110°C. After the reaction was completed, the solid was collected again by hot filtration and thoroughly washed with decane and hexane at 110°C until no free titanium compounds were detected in the solution.

[0079] The detection of the free titanium compounds was confirmed as follows. 10 mL of the supernatant liquid from the solid catalyst component was transferred with a syringe to a 100 mL sidearm Schlenk tube previously purged with nitrogen. The hexane solvent was then dried using a nitrogen stream, followed by vacuum drying for 30 minutes. 40 mL of ion-exchanged water and 10 mL of 50% by volume sulfuric acid were added and stirred for 30 minutes. This solution was transferred to a 100 mL volumetric flask through filter paper. Next, 1 mL of conc. H3PO4 as a masking agent for iron(II) ions and 5 mL of a 3% by mass aqueous solution of H2O2 as a titanium coloring reagent were added, and the volume was then adjusted to 100 mL with ion-exchanged water. The volumetric flask was shaken, and after 20 minutes, the absorbance at 420 nm was measured using UV light to detect free titanium. Washing and detection of free titanium were continued until this absorption was no longer observed. The solid titanium catalyst component (A) prepared as described above was stored as a decane slurry, and a portion of this was dried to examine the catalyst composition. The composition of the solid titanium catalyst component (A) thus obtained was 2.3 mass% titanium, 61 mass% chlorine, 19 mass% magnesium, and 12.5 mass% DIBP.

[0080] (2) Preparation of prepolymerized catalyst component A 500 mL three-necked flask equipped with a stirrer was purged with nitrogen gas, and then 400 mL of dehydrated heptane, 19.2 mmol of triethylaluminum, 3.8 mmol of dicyclopentyldimethoxysilane, and 4 g of the above solid titanium catalyst component (A) were added. The internal temperature was maintained at 20°C, and propylene was introduced with stirring. After 1 hour, stirring was stopped, and a prepolymerized catalyst component (B) was obtained in which 2 g of propylene had been polymerized per 1 g of solid titanium catalyst component (A).

[0081] (3-1) Polymerization (1) (Polymerization [Step 1]) A stainless steel autoclave equipped with a stirrer was thoroughly dried and purged with nitrogen. 6 L of dehydrated heptane, 12.5 mmol of triethylaluminum, and 0.6 mmol of dicyclopentyldimethoxysilane were then added. After the nitrogen in the system was purged with propylene, hydrogen was introduced at 0.08 MPa-G, followed by the introduction of propylene and ethylene with stirring. The introduction amounts were adjusted so that the ethylene concentration in the gas phase of the polymerization vessel was 0.6 mol%. After the system was stabilized at an internal temperature of 80°C and a total pressure of 0.8 MPa-G, 20.8 mL of a heptane slurry containing 0.10 mmol of the above prepolymerized catalyst component (B) in terms of Ti atom was added, and polymerization was carried out at 80°C for 3 hours while continuously feeding propylene.

[0082] (3-2) Polymerization (2) (Polymerization [Step 2]) After the polymerization of propylene homopolymer was completed (after the above [Step 1]), the internal temperature was lowered to 30°C and the pressure was released. Then, hydrogen at 0.60 MPa-G was charged, followed by the introduction of a propylene / ethylene mixed gas (4.0 L / min) / (2.2 L / min). Propylene / ethylene copolymerization was carried out for 60 minutes at an internal temperature of 60°C and a total pressure of 0.30 MPa-G (varied depending on the amount of introduced gas). After a predetermined time had elapsed, 50 mL of methanol was added to stop the reaction, and the temperature and pressure were reduced. The entire contents were transferred to a filter-equipped filtration tank and heated to 60°C for solid-liquid separation. The solid portion was then washed twice with 6 L of heptane at 60°C. The propylene / ethylene copolymer thus obtained was dried under vacuum. The resulting propylene polymer (A-1) had a melt flow rate (MFR) (JIS K 7210, measurement temperature 230°C, load 2.16 kg) of 0.9 g / 10 min, a Dinsol content of 86 mass%, a Dsol content of 14 mass%, an intrinsic viscosity [ηsol] in tetralin at 135°C of 2.5 dl / g, a content of structural units derived from ethylene in Dinsol of 0.6 mass%, and a content of structural units derived from ethylene in Dsol of 28 mass%.

[0083] [Production of Propylene Polymer (A-2)] The polymerization was carried out in the same manner as in the production of the propylene polymer (A-1), except that the propylene / ethylene copolymerization in the above polymerization (2) was carried out for 40 minutes. The resulting propylene polymer (A-2) had a melt flow rate (MFR) (JIS K 7210, measurement temperature 230°C, load 2.16 kg) of 0.9 g / 10 min, a Dinsol content of 92 mass%, a Dsol content of 8 mass%, an intrinsic viscosity [ηsol] in tetralin at 135°C of 2.5 dl / g, a content of structural units derived from ethylene in Dinsol of 0.6 mass%, and a content of structural units derived from ethylene in Dsol of 28 mass%.

[0084] [Production of Propylene Polymer (A-3)] In the production of the propylene-based polymer (A-1), polymerization was carried out in the same manner as in the production of the propylene-based polymer (A-1), except that in the propylene / ethylene copolymerization of the above polymerization (2), the mixed gas was introduced at a ratio of propylene / ethylene: (4.0 L / min) / (3.6 L / min). The resulting propylene polymer (A-3) had a melt flow rate (MFR) (JIS K 7210, measurement temperature 230°C, load 2.16 kg) of 0.9 g / 10 min, a Dinsol content of 86 mass%, a Dsol content of 14 mass%, an intrinsic viscosity [ηsol] in tetralin at 135°C of 2.5 dl / g, a content of structural units derived from ethylene in Dinsol of 0.6 mass%, and a content of structural units derived from ethylene in Dsol of 42 mass%.

[0085] [Ethylene-α-olefin copolymer (B)] The products manufactured by Prime Polymer Co., Ltd. shown in Table 1 were used. NZ40300J: Neozex (registered trademark) 40300J (MFR = 40 g / 10 min, density = 938 kg / m 3 ) NZ45200: Neozex (registered trademark) 45200 (MFR = 20 g / 10 min, density = 943 kg / m 3 ) SP4030: Evolue (registered trademark) SP4030 (MFR = 4.0 g / 10 min, density = 938 kg / m 3 ) HZ1700J: Hi-Zex (registered trademark) 1700J (MFR = 18 g / 10 min, density = 967 kg / m 3 ) NZ25200J: Neozex (registered trademark) 25200J (MFR = 25 g / 10 min, density = 926 kg / m 3 ) UZ30501J: UltZex (registered trademark) 30501J (MFR = 60 g / 10 min, density = 928 kg / m 3 ) SP2510: Evolue (registered trademark) SP2510 (MFR = 1.5 g / 10 min, density = 923 kg / m 3 ) SP0540: Evolue (registered trademark) SP0540 (MFR = 3.8 g / 10 min, density = 903 kg / m 3 )

[0086] [Examples 1 to 4 and Comparative Examples 1 to 10] A propylene polymer (A), an ethylene-α-olefin copolymer (B), and 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol ("Milad NX8000J" (trade name), manufactured by Milliken) as a nucleating agent (C) were blended in the formulation shown in Table 1 or Table 2. In Comparative Examples 7 and 9, the nucleating agent was not used, and other additives included 0.05 parts by mass of a phenolic antioxidant: pentaerythritol tetrakis(3-(3,5-di(tert-butyl)-4-hydroxyphenyl)propionate), 0.05 parts by mass of a phosphorus-based antioxidant: tris(2,4-di-t-butylphenyl)phosphite, and 0.09 parts by mass of calcium stearate as a neutralizing agent, and the mixture was stirred and mixed in a Henschel mixer. The resulting mixture was melt-kneaded under the following conditions using a twin-screw extruder (model: TEM35BS) manufactured by Toshiba Machine Co., Ltd. to obtain strands. Model: TEM35BS (35mm twin screw extruder) Screw rotation speed: 300 rpm Screen mesh: #200 ·Resin temperature: 240℃ The resulting strand was cooled with water and then cut with a pelletizer to obtain pellets of the propylene-based resin composition. Using these pellets, the melt flow rate (MFR) of the propylene-based resin composition was measured in accordance with JIS K 7210, and the results are shown in Tables 1 and 2.

[0087] <<Preparation of evaluation samples>> A single-layer direct blow molding machine (Tahara Corporation, model number: MSE-50E / 54M blow molding machine, heating cylinder diameter 50 mm) was used, and the molding conditions were extrusion rate 10 kg / h, cylinder temperature 210°C, and fluid blowing pressure 5.0 kg / cm. 2 A cylindrical molten parison with an outer diameter of 17 mm was molded using a crosshead die with a die hole size of 14 mm and a core size of 12 mm, and a cylindrical single-layer blown container was produced with a weight of 40 g, a capacity of 800 mL, a mouth screw outer diameter of 22.6 mm, a girth outer diameter of 75.2 mm, and an average girth wall thickness of 0.6 mm. Specifically, pellets of the propylene-based resin composition prepared above were melted using an extruder with a cylinder temperature set to 210°C, and a cylindrical molten parison was molded using a crosshead die. The parison was then sandwiched between a blow mold whose temperature was adjusted to 20°C using a water circulation circuit, and the parison was stretched and adhered to the mold using compressed air, followed by cooling and solidification to obtain a cylindrical single-layer blown container.

[0088] [Machinability] The obtained cylindrical single-layer blown container was conditioned at 24°C for 48 to 72 hours, and then at 24°C, the single-layer blown bottle was fixed upright in a drilling press (HARMONIA M20A) using a drill (Fukuda Seiko Co., Ltd., end mill, material: HSS-CO (SKH56), blade diameter 25 mm) and the top surface of the bottle mouth was cut off by 4 mm at a drilling speed of 600 to 1290 rpm. The above cutting test was carried out on n=50 samples, and the number of chips of 0.1 mm or larger that appeared on the cutting surface was visually counted. Samples whose arithmetic mean value of the number of chips of 0.1 mm or larger that appeared was 5% or less of the total number of chips that appeared were rated as "A", and samples whose arithmetic mean value of the number of chips of 0.1 mm or larger that appeared was more than 5% of the total number of chips that appeared were rated as "B".

[0089] [Transparency, haze on the body of the container] The cylindrical single-layer blown container obtained above was conditioned at 24°C for 48 to 72 hours, and the side of the container was cut off and the haze value was measured using a turbidity meter (manufactured by Nippon Denshoku Industries Co., Ltd., model number: NDH2000) in accordance with the haze test method specified in JIS K 7136. If the haze is 25% or less, it can be determined that the transparency is excellent.

[0090] [Impact resistance] The obtained cylindrical single-layer blown container was conditioned at 24°C for 48 to 72 hours, and then filled with ice water (full capacity: 800 mL) and conditioned for more than 24 hours in an environment where it was completely submerged in ice water. The conditioned container was dropped from a flat iron plate at an arbitrary height so that the bottom of the container was facing downwards. If the container did not break, the drop test was repeated by increasing the height in 20 cm intervals, and the height at which it finally broke was measured. Similar tests were conducted with n=10 for each level, and the average height at which the container broke was used as the impact resistance value. If the average height at which the container broke was 4.0 m or more, it was determined that the container had excellent impact resistance.

[0091] [Content of structural units derived from ethylene] The weight of the ethylene-derived structural unit of the propylene polymer (A) is 13 It was determined by the following measurement and calculation based on the C-NMR measurement.

[0092] - 13 C-NMR measurement conditions- Measurement equipment: LA400 nuclear magnetic resonance spectrometer manufactured by JEOL Ltd. Measurement mode: BCM (Bilevel Complete decoupling) Observation frequency: 100.4MHz Observation range: 17006.8Hz Pulse width: C nucleus 45° (7.8 μsec) Pulse repetition time: 5 seconds Sample tube: 5mmφ Sample tube rotation speed: 12Hz Accumulation count: 20,000 times Measurement temperature: 125℃ Solvent: 1,2,4-trichlorobenzene: 0.35 mL / deuterated benzene: 0.2 mL Sample amount: approx. 40 mg

[0093] From the spectrum obtained by the measurement, the ratio of the monomer sequence distribution (triad distribution) was determined in accordance with the following document (1), and the molar fraction (mol%) of the structural units derived from ethylene (hereinafter referred to as E (mol%)) and the molar fraction (mol%) of the structural units derived from propylene (hereinafter referred to as P (mol%)) in Dsol of the propylene polymer (A) were calculated. The determined E (mol%) and P (mol%) were converted into weight % according to the following (Equation 1) to calculate the weight (weight %) of the structural units derived from ethylene in Dsol of the propylene polymer (A) (hereinafter referred to as E (wt%)).

[0094] Literature (1): Kakugo, M.; Naito, Y.; Mizunuma, K.; Miyatake, T., Carbon-13 NMR determination of monomer sequence distribution in ethylene-propylene copolymers prepared with delta-titanium trichloride-diethylaluminum chloride.Macromolecules 1982,15, (4), 1150-1152

[0095] E (wt%)=E(mol%)×28×100 / [P(mol%)×42+E(mol%)×28] (Formula 1)

[0096] [Ethylene-α-olefin copolymer (B) density] The strand obtained when measuring the melt flow rate of ethylene-α-olefin copolymer (B) at a temperature of 190°C under a load of 2.16 kg (JIS K 7210) was heat-treated at 120°C for 1 hour and slowly cooled to room temperature over 1 hour. This sample was used as the sample, and its density was measured by the density gradient tube method to obtain the density of ethylene-α-olefin copolymer (B). The results are shown in Table 1 or Table 2.

[0097] [Table 1]

[0098] [Table 2]

[0099] As shown in Tables 1 and 2, it is clear that the molded articles obtained from the propylene-based resin compositions of Examples 1 to 4 are superior to those of Comparative Examples 1 to 10 in transparency, impact resistance, and machinability.

Claims

1. A propylene-based resin composition comprising: 87 to 97 parts by mass of a propylene-based polymer (A) satisfying the following requirements (A1) to (A4); 3 to 13 parts by mass of an ethylene-α-olefin copolymer (B) satisfying the following requirements (B1) to (B2) (where the total of the propylene-based polymer (A) and the ethylene-α-olefin copolymer (B) is 100 parts by mass); and 0.05 to 0.4 parts by mass of a nucleating agent (C) that satisfies the following requirement (C1) and per 100 parts by mass of the propylene-based polymer (A) and the ethylene-α-olefin copolymer (B). (A1): A melt flow rate (MFR) of 0.4 to 2.0 g / 10 min, measured at 230°C under a load of 2.16 kg in accordance with JIS K 7210 (A2): The fraction (Dinsol) insoluble in n-decane at room temperature is 80 to 90% by mass, and the fraction (Dsol) soluble in n-decane at room temperature is 10 to 20% by mass (where the total of Dinsol and Dsol is 100% by mass). (A3): The content of structural units derived from ethylene in the portion (Dinsol) insoluble in n-decane at room temperature is 0.1 to 1.5% by mass. (A4): The content of structural units derived from ethylene in the portion (Dsol) soluble in n-decane at room temperature is 20 to 40% by mass. (B1): Melt flow rate (MFR) of 5.0 to 80 / 10 min, measured at 230°C under a load of 2.16 kg in accordance with JIS K 7210 (B2): Density is 930 to 955 kg / m 3 (C1): The ratio (B1) / (A1) of the melt flow rate (MFR) of the ethylene / α-olefin copolymer (B) to the melt flow rate (MFR) of the propylene-based resin composition (A) is 12.5 to 62.

5.

2. A blow-molded article comprising the propylene-based resin composition according to claim 1.

3. An injection blow-molded article comprising the propylene-based resin composition according to claim 1.

4. The molded article according to claim 2 or 3, which is a container.

5. The molded article according to claim 4, which is a food container.

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