Method of manufacturing molded article using pin gate mold, and propylene-based resin composition used therefor

Abstract

To provide a propylene-based resin composition for pin gate mold injection molding being a material capable of reducing sink marks in a pin gate mold, and having excellent appearance, and rigidity, moldability, color development, and further impact resistance.SOLUTION: A propylene-based resin composition for pin gate mold injection molding is used when injection molding using a pin gate mold that satisfies the following condition (X1), contains a propylene-based polymer (A) that satisfies the following conditions (A1) to (A2) and a nucleus agent (B) that satisfies the following condition (B1), and satisfies the following (requirement 1) to (requirement 3).

Description

[Technical Field]

[0001] The present invention relates to a method for producing a molded article using a pin gate mold and a propylene-based resin composition used therein. [Background technology]

[0002] The method of manufacturing a molded article using a pin gate mold has been well known in the past, and a typical example is used in manufacturing cosmetic containers, particularly double-core caps. Cosmetic containers are required to have properties that allow them to withstand long-term storage of cosmetics and mechanical properties, and polypropylene resins with excellent chemical resistance and well-balanced physical properties are used for cosmetic containers and caps. Furthermore, since cosmetic containers also have an image-important aspect, it is important that they have a high-quality appearance that appeals to consumers, particularly a beautiful appearance and a luxurious feel, and various technologies have been proposed for this purpose (see Patent Documents 1 and 2).

[0003] Cosmetic containers are usually bottles or tubes with screw-top lids that fit over the top of the shoulder of the container. For containers with a relatively large outer diameter or non-circular containers, the lid is a so-called double-core cap with an outer cylindrical wall and an inner cylindrical wall, and a mechanism for aligning the lid with the container is provided to ensure that the lid closes securely in the designated position on the container and does not loosen. Patent document 3 discloses a container structure with a double-core cap that provides a sufficient clicking sensation, has a reliable anti-return effect, and can maintain the clicking sensation and engagement strength without decreasing even when the lid is opened and closed multiple times.

[0004] However, when a double-core cap such as that described in Patent Document 3 is molded from polypropylene, double-core caps, which are generally used as cosmetic containers, are often molded using a pin-gate mold because the aesthetic appearance and fine design of the cap surface are important.In such cases, sink marks tend to occur on the top surface of the cap due to the influence of the rib on the back, resulting in a double-core cap with an unsatisfactory appearance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-156910 [Patent Document 2] Japanese Patent Publication No. 2020-182831 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-145290 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0006] In view of the above problems, an object of the present invention is to provide a method for producing a molded article that reduces gate marks and sink marks when a pin gate mold is used, has excellent appearance, and is also excellent in rigidity, moldability, color development, and impact resistance, and to provide a propylene-based resin composition for pin gate mold injection molding. [Means for solving the problem]

[0007] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by using a specific propylene-based resin composition and a pin gate mold having a specific inner diameter, and have thus completed the present invention.

[0008] That is, the present invention has the following configuration. [1] A method for producing a molded article, characterized in that, when injection molding is performed using a pin gate mold satisfying the following condition (X1), a propylene-based resin composition for pin gate mold injection molding is used, the propylene-based resin composition containing a propylene polymer (A) satisfying the following conditions (A1) and (A2) and a nucleating agent (B) satisfying the following condition (B1), and satisfying the following (requirements 1) and (3): Condition(X1) The inner diameter of the pin gate of the pin gate mold is in the range of 0.1 to 1.5 mm. Condition (A1) The propylene polymer (A) is at least one selected from the group consisting of propylene homopolymers, propylene random copolymers, and propylene block copolymers. Condition (A2) The melt flow rate of the propylene polymer (A) (according to JIS K7210, 230°C, 2.16 kg load) is in the range of 5 to 100 g / 10 min. Condition (B1) The nucleating agent (B) is at least one selected from the group consisting of nonitol-based nucleating agents, sorbitol-based nucleating agents, organic phosphate-based nucleating agents, and aromatic phosphate ester-based nucleating agents. (Requirement 1) The propylene-based resin composition for pin gate mold injection molding contains 0.01 to 1 part by weight of a nucleating agent (B) based on 100 parts by weight of a propylene-based polymer (A). (Requirement 2) The propylene-based resin composition for pin gate mold injection molding has a molecular weight distribution (Mw / Mn) in the range of 1.1 to 4.5. (Requirement 3) In the spiral flow (flow length (cm) during injection molding at 200°C in a 2 mm thick spiral mold) of the propylene-based resin composition for pin gate mold injection molding, the ratio (P / D) of the flow length Pcm at the pin gate (inner diameter 0.6φmm) to the flow length Dcm at the direct gate (inner diameter 8φmm) is 0.70 or more. [2] The method for producing a molded article according to [1], wherein the propylene polymer (A) further satisfies the following condition (A3): Condition (A3) The propylene polymer (A) is a random copolymer of an α-olefin and propylene, and the content of the α-olefin is 12% by weight or less (provided that the total of the α-olefin and propylene is 100% by weight). [3] A molded article obtained by the method for producing a molded article according to [1] or [2]. [4] A propylene-based resin composition for pin-gate mold injection molding, which is used in injection molding using a pin-gate mold satisfying the following condition (X1), and which contains a propylene-based polymer (A) satisfying the following conditions (A1) and (A2) and a nucleating agent (B) satisfying the following condition (B1), and which satisfies the following (requirements 1) to (3): Condition(X1) The inner diameter of the pin gate of the pin gate mold is in the range of 0.1 to 1.5 mm. Condition (A1) The propylene polymer (A) is at least one selected from the group consisting of propylene homopolymers, propylene random copolymers, and propylene block copolymers. Condition (A2) The melt flow rate of the propylene polymer (A) (according to JIS K7210, 230°C, 2.16 kg load) is in the range of 5 to 100 g / 10 min. Condition (B1) The nucleating agent (B) is at least one selected from the group consisting of nonitol-based nucleating agents, sorbitol-based nucleating agents, organic phosphate-based nucleating agents, and aromatic phosphate ester-based nucleating agents. (Requirement 1) The propylene-based resin composition for pin gate mold injection molding contains 0.01 to 1 part by weight of a nucleating agent (B) based on 100 parts by weight of a propylene-based polymer (A). (Requirement 2) The propylene-based resin composition for pin gate mold injection molding has a molecular weight distribution (Mw / Mn) in the range of 1.1 to 4.5. (Requirement 3) In the spiral flow (flow length (cm) during injection molding at 200°C in a 2 mm thick spiral mold) of the propylene-based resin composition for pin gate mold injection molding, the ratio (P / D) of the flow length Pcm at the pin gate (inner diameter 0.6φmm) to the flow length Dcm at the direct gate (inner diameter 8φmm) is 0.70 or more. [Effects of the Invention]

[0009] The present invention provides a method for producing a molded article using a pin gate mold, which can reduce sink marks in the molded article obtained when a pin gate mold is used, and can produce a molded article that is excellent in appearance, rigidity, moldability, color development, and impact resistance, and a propylene-based resin composition for pin gate mold injection molding. [Brief explanation of the drawings]

[0010] [Figure 1] 1 shows a drawing of a double core cap. [Figure 2] 1 shows a flow sheet of propylene polymerization in Production Example 2 (production of propylene polymer (a-2)) in the Examples. [Figure 3] 1 shows a diagram of a spiral flow. DETAILED DESCRIPTION OF THE INVENTION

[0011] 1. Manufacturing method of molded body One embodiment of the present invention is a method for producing a molded article, characterized in that, when injection molding is performed using a pin gate mold satisfying the condition (X1), a propylene-based resin composition for pin gate mold injection molding that contains a propylene-based polymer (A) that satisfies the conditions (A1) and (A2) and a nucleating agent (B) that satisfies the condition (B1) and satisfies (Requirements 1) to (Requirements 3) is used (hereinafter also referred to as the "production method of the present invention"). Hereinafter, the conditions and requirements for constituting the production method of the present invention, and the components of the propylene-based resin composition for pin-gate mold injection molding (hereinafter, sometimes simply abbreviated as "propylene-based resin composition") used in the production method will be described in detail.

[0012] [1] Components constituting the propylene-based resin composition for pin gate mold injection molding (1) Propylene polymer (A) Condition (A1) The propylene polymer (A) is at least one selected from the group consisting of propylene homopolymers, propylene random copolymers, and propylene block copolymers. The propylene polymer (A) is preferably a propylene homopolymer from the viewpoint of rigidity, a propylene random copolymer from the viewpoint of transparency related to color development, and a propylene block copolymer from the viewpoint of impact resistance.

[0013] Propylene-based random copolymers and propylene-based block copolymers are copolymers of propylene and an α-olefin. The α-olefin used in the copolymerization includes an α-olefin having 2 to 20 carbon atoms, excluding propylene, such as ethylene, 1-butene, 1-hexene, and 1-octene. One or more types of α-olefins may be copolymerized with propylene. Of these, ethylene and 1-butene are preferred from the viewpoint of various mechanical properties and moldability, and ethylene is more preferred. In the case of a propylene copolymer containing ethylene, which is a more preferred α-olefin, the contents of propylene and ethylene can be measured by the measurement method described in the examples below, i.e. 13 It is a value measured by infrared spectroscopy based on a calibration curve created by infrared spectroscopy using a reference material whose composition has been verified by C-NMR. Two or more of these propylene polymers (A) may be used in combination.

[0014] Condition (A3) In one preferred embodiment of the present invention, the propylene polymer (A) is a random copolymer of an α-olefin and propylene, and has an α-olefin content of 12% by weight or less (provided that the total of the α-olefin and propylene is 100% by weight). This makes it possible to obtain a propylene-based resin composition for pin gate mold injection molding that has excellent color development, appropriate rigidity, and is capable of suppressing sink marks. The upper limit of the α-olefin content is more preferably 8% by weight or less, and even more preferably 5% by weight or less. The lower limit of the α-olefin content is usually 0.01% by weight, preferably 0.2% by weight, even more preferably 0.5% by weight, and even more preferably 0.7% by weight.

[0015] Condition (A2) The propylene polymer (A) used in the present invention has a melt flow rate (hereinafter sometimes simply abbreviated as "MFR") in accordance with JIS K7210 (230°C, 2.16 kg load) in the range of 5 to 100 g / 10 min, preferably 10 to 50 g / 10 min, and more preferably 15 to 35 g / 10 min. A melt flow rate (MFR) of 5 g / 10 min or more improves moldability and allows for satisfactory products, while a MFR of 100 g / 10 min or less improves mechanical strength and provides for satisfactory appearance through sufficient mixing, allowing for satisfactory products. The melt flow rate (MFR) can be easily adjusted by adjusting the temperature and pressure, which are polymerization conditions, when producing the propylene polymer (A), or by controlling the amount of hydrogen added in a method in which a chain transfer agent such as hydrogen is added during polymerization. Here, the melt flow rate (MFR) is a value measured in accordance with JIS K7210:1999, Appendix A, Table 1, Condition M, at a test temperature of 230°C and a nominal load of 2.16 kg.

[0016] The method for producing the propylene polymer (A) is not particularly limited, and may be, for example, a known production method using a metallocene catalyst or a Ziegler catalyst. However, from the viewpoint of easily obtaining a propylene polymer with favorable sink marks, a method using a metallocene catalyst, which can easily adjust the molecular weight distribution (Mw / Mn) to a range of 1.1 to 4.5, is preferred because it makes it easy to adjust the molecular weight distribution of the propylene resin composition for pin-gate mold injection molding to a desired range.

[0017] Examples of Ziegler catalysts include two-component catalysts consisting of a transition metal component, such as a titanium halide compound such as titanium trichloride, titanium tetrachloride, or trichloroethoxytitanium, or a contact product of the titanium halide compound with a magnesium compound such as a magnesium halide, and an organometallic component, such as an alkylaluminum compound or its halide, hydride, or alkoxide, and further three-component catalysts in which an electron-donating compound containing nitrogen, carbon, phosphorus, sulfur, oxygen, silicon, or the like is added to any of the above components.

[0018] Examples of metallocene catalysts include (r)-dichloro[1,1'-dimethylsilylenebis{2-methyl-4-(4-chlorophenyl)-4H-azulenyl}]zirconium, and more specifically, the catalyst comprises (i) a transition metal compound of Group 4 of the periodic table containing a ligand having a cyclopentadienyl skeleton (a so-called metallocene compound), (ii) a cocatalyst capable of reacting with the metallocene compound to activate it to a stable ionic state, and, if necessary, (iii) an organoaluminum compound. Any known catalyst can be used. Usable metallocene compounds are preferably bridged metallocene compounds capable of stereoregular polymerization of propylene, and more preferably bridged metallocene compounds capable of isoregular polymerization of propylene. Metallocene compounds (i) are disclosed, for example, in 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-H7-504934, and JP-A-8-85708.

[0019] Examples of the polymerization method for producing the propylene polymer (A) include a slurry polymerization method using an inert solvent in the presence of the catalyst, a solution polymerization method, a gas phase polymerization method using substantially no solvent, and a bulk polymerization method using a polymerization monomer as a solvent. For example, in the case of a slurry polymerization method, polymerization can be carried out in an inert hydrocarbon such as n-butane, isobutane, n-pentane, isopentane, hexane, heptane, octane, cyclohexane, benzene, toluene, or xylene. In the case of a bulk polymerization method, polymerization can be carried out in a liquid polymerization monomer. The polymerization temperature is usually -80 to 150°C, preferably 40 to 120°C. The polymerization pressure is preferably 1 to 60 atmospheres (0.10 to 6.08 MPa), and the molecular weight of the resulting propylene polymer (A) can be adjusted with hydrogen or other known molecular weight modifiers. The polymerization can be carried out by a continuous or batch reaction under conditions typically used for polymerization. Furthermore, the polymerization reaction can be carried out in one stage or multiple stages.

[0020] Molecular weight distribution (Mw / Mn) of propylene polymer (A) The molecular weight distribution (Mw / Mn) (hereinafter sometimes simply abbreviated as (Mw / Mn)) of the propylene polymer (A) used in the present invention is usually in the range of 1.1 to 4.5. The molecular weight distribution (Mw / Mn) is preferably from 1.2 to 3.5, more preferably from 1.5 to 3.0. A molecular weight distribution (Mw / Mn) of 1.1 or more facilitates achieving a molecular weight distribution (Mw / Mn) within the range specified in the present application during molding. The increased low-molecular weight components in the propylene-based resin composition during molding improve fluidity, allowing the molten resin to smoothly pass through the pin gate and then sufficiently fill every corner of the mold with the propylene-based resin composition for pin-gate mold injection molding. This results in a molded article that is satisfactory as a finished product. A molecular weight distribution (Mw / Mn) of 4.5 or less reduces the high-molecular weight components in the propylene-based resin composition during pin-gate mold injection molding. This reduces pressure loss when the molten resin passes through the pin gate during molding, allowing the pressure during mold filling to be adequately transmitted to the molten resin, ensuring sufficient filling of areas prone to sink marks. This results in a molded article with reduced sink marks and excellent appearance.

[0021] The molecular weight distributions described herein are determined as follows. Molecular weight distribution = (weight average molecular weight: Mw) / (number average molecular weight: Mn) Here, the weight average molecular weight (Mw) and number average molecular weight (Mn) are values ​​obtained by measurement using gel permeation chromatography (GPC), and an example of a specific method will be described below. In the GPC method, the conversion from retention volume to molecular weight is carried out using a calibration curve prepared in advance using standard polystyrene. The standard polystyrene used is, for example, the following brands manufactured by Tosoh Corporation: F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, and A1000. Each is dissolved in ODCB (containing 0.5 mg / mL BHT) to a concentration of 0.5 mg / mL, and 0.2 mL of the solution is injected to create a calibration curve. The calibration curve uses a cubic equation obtained by approximating using the least squares method. The viscosity equation [η] = K × Mα used to convert to molecular weight uses the following values. PS:K = 1.38 × 10 -4 , α=0.7 PP:K = 1.03 × 10 -4 , α=0.78 An example of the GPC measurement conditions is as follows: Apparatus: Waters GPC (ALC / GPC 150C) Detector: FOXBORO MIRAN 1A IR detector (measurement wavelength: 3.42 μm) Column: Showa Denko AD806M / S (3 columns) Mobile phase solvent: o-dichlorobenzene (ODCB) Measurement temperature: 140℃ Flow rate: 1.0ml / min Injection amount: 0.2ml Sample preparation: A 1 mg / mL solution of the sample is prepared using ODCB (containing 0.5 mg / mL of dibutylhydroxytoluene (BHT)), and the sample is dissolved at 140°C for approximately 1 hour. It is also possible to convert retention volume to molecular weight in a similar manner by using other devices, detectors, and columns with equivalent performance and creating a calibration curve using other standard samples.

[0022] The molecular weight distribution (Mw / Mn) can be adjusted to 1.1 to 4.5 by using a metallocene catalyst, which is easy and preferred. Regarding the acquisition of the propylene polymer (A), many products are commercially available from various companies, and it is possible to select and purchase a product that meets the desired conditions as the propylene polymer (A) from among these commercially available products.

[0023] (2) Nucleating agent (B) The nucleating agent (B) used in the production method of the present invention satisfies the following condition (B1).

[0024] Condition (B1) The nucleating agent (B) used in the production method of the present invention is at least one selected from the group consisting of nonitol-based nucleating agents, sorbitol-based nucleating agents, organic phosphate-based nucleating agents, and aromatic phosphate ester-based nucleating agents. By using the above-mentioned nucleating agent as the nucleating agent (B), it is possible to suppress sink marks in the molded article obtained by the production method of the present invention, and to obtain a propylene-based resin composition for pin gate mold injection molding that is particularly excellent in color development.

[0025] A nonitol-based nucleating agent that can be preferably used is, for example, a compound represented by the following formula (1): The compound represented by formula (1) is 3,5:4,6-bis[4-propylbenzylidenebis(oxy)]-1,2-nonanediol or the common name 1,2,3-trideoxy-4,6:5,7-bis-[(4-propylphenyl)methylene]-nonitol. TIFF2025124618000001.tif42159 Commercially available nucleating agents can be used as such nucleating agents. A specific example is NX8000 manufactured by Milliken.

[0026] An example of a sorbitol-based nucleating agent is a sorbitol-based nucleating agent represented by the following formula (2):

[0027] TIFF2025124618000002.tif36156

[0028] In formula (2), m and n independently represent an integer of 1 to 5; R 1 and R 2 represents an alkyl group having 1 to 18 carbon atoms or a halogen group. Examples of the nucleating agent represented by formula (2) include sorbitol-based nucleating agents such as 1·3,2·4-dibenzylidene sorbitol, 1·3,2·4-bis(p-methylbenzylidene) sorbitol, 1·3-p-chlorobenzylidene-2·4-p-methylbenzylidene sorbitol, 1·3,2·4-bis(p-ethylbenzylidene) sorbitol, and 1·3,2·4-bis(3,4-dimethylbenzylidene) sorbitol. These may be used as a mixture of two or more kinds. As the sorbitol-based nucleating agent, commercially available products can be used, specifically, Gelall MD manufactured by New Japan Chemical Co., Ltd. and Millard 3988 manufactured by Milliken.

[0029] An example of an organic phosphate nucleating agent is an organic phosphate metal salt compound represented by the following formula (3).

[0030] TIFF2025124618000003.tif49153

[0031] In equation (3), R 1 is a direct bond, sulfur, an alkylene group or an alkylidene group having 1 to 9 carbon atoms, and R 2 and R 3 are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; M is Na; and n is the valence of M.

[0032] Specific examples of the organophosphate metal salt compound represented by formula (3) include sodium-2,2'-methylene-bis-(4,6-di-t-butylphenyl) phosphate, sodium-2,2'-ethylidene-bis-(4,6-di-t-butylphenyl) phosphate, sodium-2,2'-ethylidene-bis-(4-i-propyl-6-t-butylphenyl) phosphate, sodium-2,2'-butylidene-bis-(4,6-dimethylphenyl) phosphate, sodium-2,2'-butylidene-bis-(4,6-di-t-butylphenyl) phosphate, sodium-2,2'-t-octylmethylene-bis-(4,6-methylphenyl) phosphate, and sodium-2,2'-t-octylmethylene-bis Examples include sodium 2,2'-methylene-bis-(4-methyl-6-t-butylphenyl)phosphate, sodium 2,2'-methylene-bis-(4-ethyl-6-t-butylphenyl)phosphate, sodium (4,4'-dimethyl-6,6'-di-t-butyl-2,2'-biphenyl)phosphate, sodium 2,2'-ethylidene-bis-(4-s-butyl-6-t-butylphenyl)phosphate, sodium 2,2'-methylene-bis-(4,6-dimethylphenyl)phosphate, sodium 2,2'-methylene-bis-(4,6-diethylphenyl)phosphate, and mixtures of two or more thereof. Of these, sodium 2,2'-methylene-bis-(4,6-di-t-butylphenyl)phosphate is particularly preferred. As such a nucleating agent, commercially available products can be used, specifically NA-11 manufactured by ADEKA Corporation.

[0033] Examples of aromatic phosphate ester-based nucleating agents include aromatic phosphate esters represented by the following formula (4).

[0034] TIFF2025124618000004.tif51152

[0035] In equation (4), R 1represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R 2 and R 3 are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms; M represents a metal atom of Group III or IV of the periodic table; X represents HO- when M represents a metal atom of Group III of the periodic table, and represents O= or (HO)2- when M represents a metal atom of Group IV of the periodic table.

[0036] Specific examples of the aromatic phosphate esters represented by formula (4) include, for example, hydroxyaluminum-bis[2,2'-methylene-bis(4,6-dimethylphenyl)phosphate], hydroxyaluminum-bis[2,2'-ethylidene-bis(4,6-dimethylphenyl)phosphate], hydroxyaluminum-bis[2,2'-methylene-bis(4,6-diethylphenyl)phosphate], hydroxyaluminum-bis[2,2'-ethylidene-bis(4,6-diethylphenyl)phosphate], hydroxyaluminum-bis[2,2'-methylene-bis(4,6-di-t-butylphenyl)phosphate], and hydroxyaluminum-bis[2,2'-ethylidene-bis(4,6-di-t-butylphenyl)phosphate], hydroxyaluminum-bis[2,2'-methylene-bis(4-methyl-6-t-butylphenyl)phosphate], hydroxyaluminum-bis[2, 2'-ethylidene-bis(4-methyl-6-t-butylphenyl) phosphate], hydroxyaluminum bis[2,2'-methylene-bis(4-ethyl-6-t-butylphenyl) phosphate], hydroxyaluminum bis[2,2'-ethylidene-bis(4-ethyl-6-t-butylphenyl) phosphate], hydroxyaluminum bis[2,2'-methylene-bis(4-i-propyl-6-t-butylphenyl) phosphate], Examples include hydroxyaluminum bis[2,2'-ethylidene-bis(4-i-propyl-6-t-butylphenyl)phosphate], and preferred examples include hydroxyaluminum bis[2,2'-methylene-bis(4,6-di-t-butylphenyl)phosphate], hydroxyaluminum bis[2,2'-ethylidene-bis(4,6-di-t-butylphenyl)phosphate], and mixtures of two or more of these.

[0037] The aromatic phosphate ester nucleating agent represented by formula (4) is effective in improving the dispersibility of the main component of the nucleating agent when used in combination with an organic alkali metal salt. The organic alkali metal salt can refer to at least one organic alkali metal salt selected from the group consisting of alkali metal carboxylates, alkali metal β-diketonates, and alkali metal β-ketoacetate salts. Examples of the alkali metal constituting the organic alkali metal salt include lithium, sodium, and potassium. Examples of the carboxylic acid constituting the alkali metal carboxylate include aliphatic monocarboxylic acids such as acetic acid, propionic acid, acrylic acid, octylic acid, isooctyl acid, nonanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, ricinoleic acid, 12-hydroxystearic acid, behenic acid, montanic acid, melissic acid, β-dodecylmercaptoacetic acid, β-dodecylmercaptopropionic acid, β-N-laurylaminopropionic acid, and β-N-methyl-lauroylaminopropionic acid; aliphatic polycarboxylic acids such as malonic acid, succinic acid, adipic acid, maleic acid, azelaic acid, sebacic acid, dodecanedioic acid, citric acid, butanetricarboxylic acid, and butanetetracarboxylic acid; naphthacarboxylic acid, hydroxybenzoates ... alicyclic mono- or polycarboxylic acids such as benzoic acid, toluic acid, xylyl acid, ethyl benzoic acid, 4-t-butyl benzoic acid, salicylic acid, phthalic acid, trimellitic acid, and pyromellitic acid; and the like. Examples of the β-diketone compounds constituting the alkali metal β-diketonates include acetylacetone, pivaloylacetone, palmitoylacetone, benzoylacetone, pivaloylbenzoylacetone, and dibenzoylmethane. Examples of the β-ketoacetate ester constituting the alkali metal β-ketoacetate salt include ethyl acetoacetate, octyl acetoacetate, lauryl acetoacetate, stearyl acetoacetate, ethyl benzoylacetate, and lauryl benzoylacetate. The alkali metal carboxylate, alkali metal β-diketonate, or alkali metal β-ketoacetate, which are components of the organic alkali metal salt, are salts of the alkali metal with a carboxylic acid, a β-diketone compound, or a β-ketoacetate, respectively, and can be produced by a conventionally known method. Among these alkali metal salt compounds, alkali metal aliphatic monocarboxylates, particularly lithium aliphatic carboxylates, are preferred, with aliphatic monocarboxylates having 8 to 20 carbon atoms being particularly preferred.

[0038] As such a nucleating agent, commercially available products can be used, specifically NA-21 manufactured by ADEKA Corporation.

[0039] The propylene-based resin composition used in the production method of the present invention contains at least one nucleating agent defined in the condition (B1), but may contain other nucleating agents within a range that does not impair the effects of the present invention.

[0040] Such other nucleating agents include those represented by the following formula (5):

[0041] TIFF2025124618000005.tif42152

[0042] In formula (5), M1 and M2 are each a lithium ion or jointly represent a single metal cation independently selected from the group consisting of calcium, strontium, zinc, magnesium, and monobasic aluminum; R1, R2, R3, R4, R5, R6, R7, R8, R9, and R 10are the same or different and are each selected from the group consisting of hydrogen, C1-C9 alkyl (wherein any two vicinal (bonded to adjacent carbons) or geminal (bonded to the same carbon) alkyl groups may be joined together to form a hydrocarbon ring having up to 6 carbon atoms), hydroxy, C1-C9 alkoxy, C1-C9 alkyleneoxy, amine and C1-C9 alkylamine, halogen (fluorine, chlorine, bromine, and iodine), and phenyl. Here, the term "monobasic aluminum" is well known and is intended to include an aluminum hydroxide group as a single cation to which two carboxylic acid groups are attached. Furthermore, in each of these possible salts, the configuration of the asymmetric carbon atom may be either cis or trans, with cis being preferred. The nucleating agent represented by formula (5) may be used in combination with other compounds for the purpose of preventing aggregation and the like. As such a nucleating agent, commercially available products can be used. Specifically, Hyperform HPN68L manufactured by Milliken can be mentioned. The structure of the nucleating agent component of Hyperform HPN68L is shown below.

[0043] TIFF2025124618000006.tif38149

[0044] The content of the nucleating agent represented by formula (5) that can be used in the propylene-based resin composition is 0.005 to 0.15 parts by weight based on 100 parts by weight of the propylene-based polymer (A).

[0045] Other examples of the nucleating agent include a nucleating agent made of a triaminobenzene derivative represented by the following formula (6).

[0046] TIFF2025124618000007.tif51148

[0047] In the formula (6), R1 to R3 are t-butyl.

[0048] Examples of the nucleating agent composed of a triaminobenzene derivative include IRGACLEAR XT386, manufactured by BASF. The content of the nucleating agent composed of a triaminobenzene derivative that can be used in the propylene - based resin composition is 0.005 to 0.04 parts by weight with respect to 100 parts by weight of the propylene - based polymer (A).

[0049] (3) Additives 1) Neutralizing agent In the propylene - based resin composition used in the production method of the present invention, it is preferable to blend a neutralizing agent from the viewpoint of preventing metal corrosion of a molding machine, a mold, etc. Specific examples of the neutralizing agent include fatty acid metal salts such as calcium stearate, zinc stearate, and magnesium stearate, hydrotalcite (trade name: DHT - 4A, a magnesium - aluminum composite hydroxide salt represented by the following formula (7) manufactured by Kyowa Chemical Industry Co., Ltd.), Mizukarak (trade name, a lithium - aluminum composite hydroxide salt represented by the following formula (8) manufactured by Mizusawa Chemical Industry Co., Ltd.), and the like.

[0050] [[ID=IPD=13]] Mg 1-x Al x (OH)2(CO3) x / 2 ·mH2O …(7) [In the formula, x is 0 < x ≤ 0.5, and m is a number of 3 or less.]

[0051] [Al2Li(OH)6] n X·mH2O …(8) [In the formula, X is an inorganic or organic anion, n is the valence of the anion (X), and m is 3 or less.]

[0052] The blending amount of the neutralizing agent is preferably in the range of 0.005 to 0.2 parts by weight, and more preferably in the range of 0.02 to 0.15 parts by weight with respect to 100 parts by weight of the propylene - based polymer (A).

[0053] 2) Lubricant The propylene-based resin composition used in the production method of the present invention may contain a lubricant to the extent that the effects of the present invention are not impaired. Examples of lubricants include known lubricants, but preferred are oleic acid amide, erucic acid amide, butyl stearate, and silicone oil. Specific examples of silicone oils include dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, α-ω-bis(3-hydroxypropyl)polydimethylsiloxane, polyoxyalkylene (C2-C4) dimethylpolysiloxane, and condensates of polyorgano (C1-C2 alkyl and / or phenyl)siloxane and polyalkylene (C2-C3) glycol. Among these, oleic acid amide and erucic acid amide are preferred because they efficiently achieve superior effects relative to the amount used. These lubricants may be used alone or in combination. Adding silicones such as dimethylpolysiloxane not only prevents scratches that occur during molding, but also prevents burns that occur inside the cylinder and hot runner.

[0054] The amount of the lubricant added is preferably 0.001 to 0.5 parts by weight, more preferably 0.01 to 0.15 parts by weight, and particularly preferably 0.03 to 0.1 parts by weight, per 100 parts by weight of the propylene polymer (A) from the viewpoints of effectiveness and economy.

[0055] 3) Other additives The propylene-based resin composition used in the production method of the present invention may contain, in addition to the above-mentioned components, various additives used as stabilizers for propylene-based polymers, such as various antioxidants, ultraviolet absorbers, and light stabilizers.

[0056] Specifically, examples of the antioxidant include bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, di-stearyl-pentaerythritol diphosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, tris(2,4-di-t-butylphenyl)phosphite, tetrakis(2,4-di-t-butylphenyl)- Examples of the antioxidant include phosphorus-based antioxidants such as 4,4'-biphenylene-diphosphonite and tetrakis(2,4-di-t-butyl-5-methylphenyl)-4,4'-biphenylene-diphosphonite, and thio-based antioxidants such as di-stearyl-β,β'-thio-di-propionate, di-myristyl-β,β'-thio-di-propionate and di-lauryl-β,β'-thio-di-propionate. Further examples of the antioxidant include phenolic antioxidants such as 2,6-di-t-butyl-p-cresol, tetrakis[methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)]methane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, and tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate.

[0057] Examples of the ultraviolet absorber include 2-hydroxy-4-n-octoxybenzophenone, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole, and 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole.

[0058] Light stabilizers include n-hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate, 2,4-di-t-butylphenyl-3',5'-di-t-butyl-4'-hydroxybenzoate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, dimethyl succinate-2-(4-hydroxy-2,2,6,6-tetramethyl-1-piperidyl)ethanol condensate, poly{[6-[(1,1,3,3-tetramethylbutyl)acetate] and light stabilizers such as N,N'-bis(3-aminopropyl)ethylenediamine-2,4-bis[N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino]-6-chloro-1,3,5-triazine condensate.

[0059] Further usable additives include amine-based antioxidants represented by the following formula (9) or (10), lactone-based antioxidants such as 5,7-di-t-butyl-3-(3,4-dimethyl-phenyl)-3H-benzofuran-2-one, and vitamin E-based antioxidants such as those represented by the following formula (11).

[0060] TIFF2025124618000008.tif29150

[0061] TIFF2025124618000009.tif35153

[0062] TIFF2025124618000010.tif27149

[0063] Furthermore, other additives such as antistatic agents, dispersants such as fatty acid metal salts, and other resins such as polyethylene, olefin elastomers, and non-olefin elastomers may be added within the range that does not impair the effects of the present invention.

[0064] [2] Method for producing propylene-based resin composition for pin gate mold injection molding The propylene-based resin composition for pin-gate mold injection molding used in the production method of the present invention can be obtained by charging and mixing the propylene-based polymer (A), the nucleating agent (B), and, if necessary, other additives and other resins such as polyethylene, into a Henschel mixer (trade name), a super mixer, a ribbon blender, or the like, and then melt-kneading the mixture at a temperature of 190 to 260°C using a conventional single-screw extruder, twin-screw extruder, a Banbury mixer, a plavender, a roll, or the like.

[0065] [3] Propylene-based resin composition for pin gate mold injection molding The propylene-based resin composition for pin gate mold injection molding used in the production method of the present invention satisfies the following (Requirement 1) to (Requirement 3).

[0066] (Requirement 1) The propylene-based resin composition for pin gate mold injection molding contains 0.01 to 1 part by weight of a nucleating agent (B) based on 100 parts by weight of a propylene-based polymer (A).

[0067] In the production method of the present invention, the propylene-based resin composition for pin gate mold injection molding contains 0.01 to 1 part by weight of a nucleating agent (B) based on 100 parts by weight of a propylene-based polymer (A). By including the nucleating agent in the above range, it is possible to suppress sink marks in the molded article obtained by the production method of the present invention, and to obtain good color development and rigidity. The content of the nucleating agent is preferably 0.015 to 0.5 parts by weight, more preferably 0.02 to 0.4 parts by weight, based on 100 parts by weight of the propylene polymer (A).

[0068] (Requirement 2) The molecular weight distribution (Mw / Mn) of the propylene-based resin composition for pin gate mold injection molding used in the production method of the present invention is in the range of 1.1 to 4.5. The molecular weight distribution (Mw / Mn) is preferably from 1.2 to 3.5, more preferably from 1.5 to 3.0. When the molecular weight distribution (Mw / Mn) is 1.1 or more, the propylene-based resin composition for pin gate mold injection molding contains an increased amount of low-molecular-weight components during molding, improving fluidity, allowing the molten resin to smoothly pass through the pin gate and then sufficiently fill every corner of the mold with the propylene-based resin composition for pin gate mold injection molding, resulting in a molded article that is satisfactory as a finished product. When the molecular weight distribution (Mw / Mn) is 4.5 or less, the propylene-based resin composition for pin gate mold injection molding contains a decreased amount of high-molecular-weight components, reducing pressure loss when the molten resin passes through the pin gate during molding, allowing the pressure during mold filling to be sufficiently transmitted to the molten resin, ensuring sufficient filling of areas prone to sink marks with the molten resin. This results in a molded article with reduced sink marks and excellent appearance obtained by the manufacturing method of the present invention.

[0069] The molecular weight distribution of the propylene-based resin composition for pin-gate mold injection molding described in this specification is determined by gel permeation chromatography (GPC) in the same manner as the molecular weight distribution (Mw / Mn) of the propylene-based polymer (A).

[0070] The molecular weight distribution (Mw / Mn) of the propylene-based resin composition for pin-gate mold injection molding can be adjusted to 1.1 to 4.5 by using a propylene-based polymer (A) produced using a metallocene catalyst, or by adding a peroxide during granulation to narrow the molecular weight distribution (Mw / Mn) even in the case of a polymerization product produced using a Ziegler catalyst with a large molecular weight distribution (Mw / Mn).

[0071] (Requirement 3) The propylene-based resin composition for pin-gate mold injection molding used in the production method of the present invention has a spiral flow (flow length (cm) during injection molding at 200°C in a 2 mm-thick spiral mold) in which the ratio (P / D) of the flow length P cm at a pin gate (inner diameter 0.6 mm) to the flow length D cm at a direct gate (inner diameter 8 mm) is 0.70 or more. The ratio (P / D) is preferably 0.71 or more, and more preferably 0.75 or more. The larger the ratio (P / D), the less pressure loss there is when the molten resin passes through the gate during molding. In order to obtain molded products with stable suppression of sink marks, the ratio (P / D) needs to be 0.70 or higher. The upper limit of the ratio (P / D) is 1.0, preferably 0.95, and more preferably 0.90. By setting the upper limit of the ratio (P / D) to such a value, various physical properties of the resulting propylene-based resin composition for pin gate mold injection molding can be kept within a favorable range. As mentioned above, the larger the ratio (P / D), the smaller the pressure loss when the molten resin passes through the gate during molding. However, such a propylene-based resin composition for pin gate mold injection molding may have too good fluidity, which may make it more susceptible to flash during molding. In this specification, spiral flow is measured using a mold having the shape shown in FIG. 3 and an SE180EV-A injection molding machine manufactured by Sumitomo Heavy Industries, Ltd. under the conditions shown in Table 4. However, it is also possible to measure using other injection molding machines with equivalent performance.

[0072] TIFF2025124618000011.tif102156

[0073] [4] Manufacturing method for molded body The production method of the present invention is a method for producing a molded article with excellent appearance, i.e., a molded article with excellent surface appearance and excellent designability due to small gate marks and sink marks, by injection molding using the propylene-based resin composition for pin gate mold injection molding described above in detail with a pin gate mold that satisfies the condition (X1).

[0074] Condition(X1) The inner diameter of the pin gate of the pin gate mold is in the range of 0.1 to 1.5 mm.

[0075] When producing a molded product, if a direct gate mold with a large inner diameter is used, large gate marks are left and the gate processing marks are difficult to process, which tends to impair the surface appearance. Furthermore, if an attempt is made to prevent impairing the surface appearance of the resulting molded product, restrictions are imposed on the shape of the molded product, which may impair the design. In the production method of the present invention, by using a pin-gate mold and a specific propylene-based resin composition, a molded article can be obtained without impairing the surface appearance, and further, a molded article having excellent desired design properties can be easily obtained. The inner diameter of the pin gate is preferably 0.2 to 1.0 mm, more preferably 0.3 to 0.8 mm. By setting the inner diameter of the pin gate within this range, when the specific propylene-based resin composition used in the present invention is used, the resin is sufficiently filled into the pin gate mold, maintaining moldability, and the gate marks and sink marks are small, resulting in an excellent surface appearance and a molded product with excellent design.

[0076] The pin gate mold used in the manufacturing method of the present invention is preferably an inner pin gate, since gate marks do not remain on the surface of the molded article, resulting in a molded article with better surface appearance and good design properties.

[0077] In the production method of the present invention, by using the propylene-based resin composition described above in detail, gate marks and sink marks that may occur when a pin-gate mold is used can be reduced, and a molded article that is excellent in appearance, rigidity, moldability, color development, and impact resistance can be provided.

[0078] The manufacturing method of the present invention involves obtaining a molded article by injection molding, and the injection molding machine that can be used can be selected from, for example, commonly used known molding machines having the desired performance.

[0079] As for the conditions for injection molding, the molding temperature (cylinder temperature) is usually 180 to 280°C, preferably 200 to 240°C, and more preferably 190 to 210°C. The temperature of the mold is usually 10 to 60°C, and preferably 15 to 50°C.

[0080] [5] Molded body Another aspect of the present invention is a molded article obtained using the production method of the present invention (hereinafter also referred to as "molded article of the present invention"). Specific molded articles include cosmetic containers (for example, liquid bottles, particularly skin care cosmetic containers, and more preferably, lids for these containers), food containers (pudding containers, jelly containers, yogurt containers, steamed egg containers, instant ramen containers, chilled coffee containers, dessert containers, lunch box containers, etc.), caps (PET bottle caps, one-piece caps, two-piece caps, instant coffee caps, etc.), medical instruments and containers (disposable instruments such as disposable syringes and their parts, catheter tubes, infusion bags, blood bags, vacuum blood collection tubes, surgical nonwoven fabrics, blood filters, and blood circuits). and parts for artificial organs such as artificial lungs and artificial anus, dialyzers, prefilled syringes, kit preparations, drug containers, test tubes, sutures, compress bases, dental material parts, orthopedic material parts, contact lens cases, contact lens manufacturing molds, PTP, SP / sachets, P vials, eye drop containers, drug solution containers, long-term liquid storage containers, etc.), medical containers (infusion packs), daily necessities (wardrobe cases, buckets, washbasins, writing implements), automobile parts (instrument panels, bumpers, light bodies, etc.), electrical parts (casings for various electrical devices, etc.), solar cell encapsulants, films, fibers, sheets, etc., but the molded article of the present invention is particularly suitable for cosmetic containers.

[0081] 2. Propylene-based resin composition for pin gate mold injection molding Another embodiment of the present invention is a propylene-based resin composition for pin-gate mold injection molding, which is used in injection molding using a pin-gate mold satisfying the following condition (X1), and which contains a propylene-based polymer (A) satisfying the following conditions (A1) and (A2) and a nucleating agent (B) satisfying the following condition (B1), and which satisfies the following (Requirements 1) to (Requirements 3) (hereinafter also referred to as the "propylene-based resin composition of the present invention"). Condition(X1) The inner diameter of the pin gate of the pin gate mold is in the range of 0.1 to 1.5 mm. Condition (A1) The propylene polymer (A) is at least one selected from the group consisting of propylene homopolymers, propylene random copolymers, and propylene block copolymers. Condition (A2) The melt flow rate of the propylene polymer (A) (according to JIS K7210, 230°C, 2.16 kg load) is in the range of 5 to 100 g / 10 min. Condition (B1) The nucleating agent (B) is at least one selected from the group consisting of nonitol-based nucleating agents, sorbitol-based nucleating agents, organic phosphate-based nucleating agents, and aromatic phosphate ester-based nucleating agents. (Requirement 1) The propylene-based resin composition for pin gate mold injection molding contains 0.01 to 1 part by weight of a nucleating agent (B) based on 100 parts by weight of a propylene-based polymer (A). (Requirement 2) The propylene-based resin composition for pin gate mold injection molding has a molecular weight distribution (Mw / Mn) in the range of 1.1 to 4.5. (Requirement 3) In the spiral flow (flow length (cm) during injection molding at 200°C in a 2 mm thick spiral mold) of the propylene-based resin composition for pin gate mold injection molding, the ratio (P / D) of the flow length Pcm at the pin gate (inner diameter 0.6φmm) to the flow length Dcm at the direct gate (inner diameter 8φmm) is 0.70 or more.

[0082] Details of the propylene-based resin composition of the present invention, such as the propylene-based polymer (A), the nucleating agent (B), and other additives, (Requirements 1) to (Requirement 3), and condition (X1), are the same as those described in detail for the propylene-based resin composition used in the production method of the present invention.

[0083] (Requirement 2) The molecular weight distribution (Mw / Mn) of the propylene-based resin composition for pin gate mold injection molding of the present invention is in the range of 1.1 to 4.5. The molecular weight distribution (Mw / Mn) is preferably from 1.2 to 3.5, more preferably from 1.5 to 3.0. When the molecular weight distribution (Mw / Mn) is 1.1 or more, the propylene-based resin composition for pin gate mold injection molding has an increased amount of low-molecular-weight components during molding, improving fluidity, allowing the molten resin to smoothly pass through the pin gate and then sufficiently fill every corner of the mold with the propylene-based resin composition for pin gate mold injection molding, resulting in a molded article that is satisfactory as a finished product. When the molecular weight distribution (Mw / Mn) is 4.5 or less, the propylene-based resin composition for pin gate mold injection molding has a decreased amount of high-molecular-weight components, reducing pressure loss when the molten resin passes through the pin gate during molding, allowing the pressure during mold filling to be sufficiently transmitted to the molten resin, allowing the molten resin to sufficiently fill areas prone to sink marks, resulting in a molded article with reduced sink marks and excellent appearance.

[0084] The molecular weight distribution of the propylene-based resin composition for pin gate mold injection molding of the present invention is determined by gel permeation chromatography (GPC) in the same manner as the molecular weight distribution (Mw / Mn) of the propylene-based polymer (A).

[0085] The molecular weight distribution (Mw / Mn) of the propylene-based resin composition for pin-gate mold injection molding can be adjusted to 1.1 to 4.5 by using a propylene-based polymer (A) produced using a metallocene catalyst, or by adding a peroxide during granulation to narrow the molecular weight distribution (Mw / Mn) even in the case of a polymerization product produced using a Ziegler catalyst with a large molecular weight distribution (Mw / Mn).

[0086] (Requirement 3) The propylene-based resin composition for pin-gate mold injection molding of the present invention has a spiral flow (flow length (cm) during injection molding at 200°C in a 2 mm-thick spiral mold) in which the ratio (P / D) of the flow length P cm at a pin gate (inner diameter 0.6 mm) to the flow length D cm at a direct gate (inner diameter 8 mm) is 0.70 or more. The ratio (P / D) is preferably 0.71 or more, and more preferably 0.75 or more. The larger the ratio (P / D), the less pressure loss there is when the molten resin passes through the gate during molding. In order to obtain molded products with stable suppression of sink marks, the ratio (P / D) needs to be 0.70 or higher. The upper limit of the ratio (P / D) is 1.0, preferably 0.95, and more preferably 0.90. By setting the upper limit of the ratio (P / D) to such a value, various physical properties of the resulting propylene-based resin composition for pin gate mold injection molding can be kept within a favorable range. As mentioned above, the larger the ratio (P / D), the smaller the pressure loss when the molten resin passes through the gate during molding. However, such a propylene-based resin composition for pin gate mold injection molding may have too good fluidity, which may make it more susceptible to flash during molding. In this specification, spiral flow is measured using a mold having the shape shown in FIG. 3 and an SE180EV-A injection molding machine manufactured by Sumitomo Heavy Industries, Ltd. under the conditions shown in Table 4 above, but it is also possible to measure using other injection molding machines with equivalent performance.

[0087] The propylene-based resin composition of the present invention satisfies the above requirements and conditions, and is therefore a material that can reduce gate marks and sink marks when a pin-gate mold is used, and has excellent appearance, rigidity, moldability, color development, and impact resistance. [Example]

[0088] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention. The measurement methods for physical properties, evaluation methods, resins, and additives used in the examples and comparative examples are as follows.

[0089] <1. Measurement and evaluation methods for physical properties> (A) Molecular weight distribution (Mw / Mn) (GPC method) The molecular weight distribution (Mw / Mn) was measured by the following method. Molecular weight distribution = (weight average molecular weight: Mw) / (number average molecular weight: Mn) Here, the weight average molecular weight (Mw) and number average molecular weight (Mn) are values ​​obtained by measurement using gel permeation chromatography (GPC), and specifically, they were determined as follows. The retention volume was converted into molecular weight using a calibration curve prepared in advance using standard polystyrene. The standard polystyrenes used were the following brands manufactured by Tosoh Corporation: F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, and A1000. Each was dissolved in ODCB (containing 0.5 mg / mL of BHT) to a concentration of 0.5 mg / mL, and 0.2 mL of the solution was injected to create a calibration curve. The calibration curve used a cubic equation obtained by approximating using the least squares method. The viscosity equation used for conversion to molecular weight was [η] = K × M α The following values ​​were used: PS:K = 1.38 × 10 -4 , α=0.7 PP:K = 1.03 × 10 -4 , α=0.78 The GPC measurement conditions were as follows: Apparatus: Waters GPC (ALC / GPC 150C) Detector: FOXBORO MIRAN 1A IR detector (measurement wavelength: 3.42 μm) Column: Showa Denko AD806M / S (3 columns) Mobile phase solvent: o-dichlorobenzene (ODCB) Measurement temperature: 140℃ Flow rate: 1.0ml / min Injection amount: 0.2ml Sample preparation: A 1 mg / mL solution of the sample was prepared using ODCB (containing 0.5 mg / mL of BHT) and dissolved at 140°C for approximately 1 hour. When no peroxide is used during melt-kneading, the molecular weight distribution (Mw / Mn) of the propylene-based resin composition for pin gate mold injection molding and the molecular weight distribution (Mw / Mn) of the propylene-based polymer (A) are equal. Therefore, when no peroxide is used during melt-kneading, the molecular weight distribution (Mw / Mn) of the propylene-based polymer (A) was measured and used as the molecular weight distribution (Mw / Mn) of the propylene-based resin composition for pin gate mold injection molding. (a) Ethylene content 13 The ethylene-propylene random copolymer whose composition was verified by C-NMR was used as the standard substance. -1 The ethylene content in the random copolymer was measured by infrared spectroscopy using the characteristic absorption band of (a calibration curve was prepared). Based on the prepared calibration curve, a propylene-based polymer sample was press-molded into a film of approximately 500 μm thickness, and the ethylene content was measured by infrared spectroscopy. Here, the propylene and ethylene contents of the reference materials for creating the calibration curve are as follows: 13 The value was measured by C-NMR. 13 The C-NMR spectrum was analyzed according to the analytical method described in JP-A-2006-307120, and the contents of propylene and ethylene were calculated. Equipment: JEOL-GSX270 manufactured by JEOL Ltd. Concentration: 300mg / 2mL Solvent: orthodichlorobenzene (c) Melt flow rate (MFR) Measurements were performed in accordance with JIS K7210:1999, Appendix A, Table 1, Condition M, at a test temperature of 230°C and a nominal load of 2.16 kg. (d) Flexural modulus Measurement was carried out in accordance with JIS K7171. (E) Charpy impact strength The Charpy impact strength at 23°C was measured in accordance with JIS K7111. (Ka) Hayes The haze at t=1 mm was measured in accordance with JIS K7136. (G) Presence of sink marks and burrs (double core cap) Each material was used in an injection molding machine (SE180EV-A manufactured by Sumitomo Heavy Industries, Ltd.) to mold a double-core cap (inner diameter of pin gate: 0.6 mm) using the mold shown in Figure 1 according to the molding conditions listed in Table 1, and the presence or absence of sink marks on the top surface of the double-core cap was visually checked. The presence or absence of burrs on the double-core cap was also visually checked. Presence of sink marks 〇: No sink marks ×: Sink marks present Presence of burrs 〇: No burrs ×: Burrs present

[0090] (H) Spiral flow Each material was molded using an injection molding machine (SE180EV-A manufactured by Sumitomo Heavy Industries, Ltd.) with the spiral flow mold shown in Figure 3 according to the molding conditions listed in Table 4, and the flow length (cm) was measured. Note that the first 10 shots were not used for measurement, and the average value of the next 5 shots was used as the flow length measurement result. In addition, this mold had interchangeable gates, and measurements were taken using both a direct gate (gate diameter 8φmm) and a pin gate (gate diameter 0.6φmm).

[0091] TIFF2025124618000012.tif111154

[0092] <2. Resins and additives> 2-1. Propylene polymer (A) (1) Production Example 1 (Production of a-1) (i) Preparation of catalyst (a) Chemical treatment of layered silicates A 3 L separable flask equipped with a stirring blade and reflux device was charged with 2264 g of pure water and 670 g of 96% sulfuric acid. The flask was heated in an oil bath until the internal temperature reached 90 °C. Upon reaching the target temperature, 400 g of commercially available granulated montmorillonite (structure: Benclay SL, manufactured by Mizusawa Industrial Chemicals, Inc., average particle size: 18 μm, particle size distribution = 7-30 μm, composition (wt%): Al = 9.11, Si = 32.91) was added and stirred. The acid concentration was 19.7 wt%, or 16.4 mmol / g relative to the clay. The reaction was then allowed to proceed for 300 minutes while maintaining the temperature at 90 °C. The reaction was stopped by pouring the reaction solution into 2 L of pure water. The resulting slurry was filtered using a filter with a suction bottle and an aspirator, followed by three washes with 4 L of pure water. The recovered cake was dried overnight at 120°C, and then 100g was weighed out and used in the next step. The recovered cake was added to an aqueous solution of 108g of lithium sulfate hydrate dissolved in 481mL of pure water in a 1L plastic beaker, and the mixture was allowed to react at room temperature for 2 hours. The slurry was filtered using an apparatus consisting of a Nutsche filter and a suction bottle connected to an aspirator, and washed three times with 3L of pure water. The collected cake was dried overnight at 120°C. As a result, 73.3 g of chemically treated montmorillonite was obtained. When this was sieved through a sieve with 53 μm openings, 72.3 g of the fraction that passed through the sieve was obtained, accounting for 98.7% of the total weight. When the average particle size of this was measured using laser diffraction / scattering, it was found to be 17.1 μm. The composition (wt%) of the obtained chemically treated montmorillonite was 6.16% Al and 39.15% Si, with a molar ratio of Al to Si of 0.164. The entire amount of the chemically treated montmorillonite thus obtained was placed in a flask having a volume of 200 mL and dried under reduced pressure at 200°C for approximately 3 hours (2 hours or more after the bumping subsided).

[0093] (b) Catalyst preparation 19.99 g of dried montmorillonite obtained from the chemical treatment of the layered silicate described above was weighed into a 1 L flask, and 131 mL of heptane and 69.0 mL of a heptane solution of triisobutylaluminum (TiBA) (49.4 mmol, concentration 141.9 mg / L) were added and stirred at room temperature for 1 hour. The mixture was then washed with heptane until the residual liquid ratio reached 1 / 100, and finally the slurry volume was adjusted to 100 mL. Next, 181 mL of heptane and 3.1 mL of a heptane solution of TnOA (concentration 143.6 mg / mL, 1214 μmol) were added to the TiBA-treated montmorillonite heptane slurry. To this flask (volume 200 mL), a slurry of 244 mg (300.1 μmol) of (r)-[1,1'-dimethylsilylenebis{2-methyl-4-(4-chlorophenyl)-4H-azulenyl}]hafnium dichloride (synthesized according to the example in JP-A-10-110136) in heptane (48 mL) was added, and the mixture was stirred at 60°C for 60 minutes. The montmorillonite heptane slurry was introduced into a 1 L stirred autoclave that had been thoroughly dried and purged with nitrogen. Once the temperature inside the autoclave stabilized at 40°C, propylene was fed at a rate of 10 g / hour to maintain the temperature constant. After 4 hours, the propylene feed was stopped, and the temperature was maintained for another 1 hour. After completion of the prepolymerization, the remaining monomer was purged, and the prepolymerized catalyst slurry was recovered from the autoclave. The recovered prepolymerized catalyst slurry was allowed to stand, and 215 mL of the supernatant was removed. Subsequently, 8.6 mL (6.1 mmol) of a heptane solution of triisobutylaluminum (TiBA) was added at room temperature, followed by drying under reduced pressure at 40°C for 1 hour, recovering 65.17 g of solid catalyst. The prepolymerization ratio (the value obtained by dividing the amount of prepolymerized polymer by the amount of solid catalyst) was 2.16 g / g. The amount of Hf complex supported per amount of solid catalyst of this catalyst was 12.3 μmol. The average particle size was 29.1 μm.

[0094] (ii) Production of propylene-ethylene copolymer Internal volume 105m 3Continuous production of propylene-ethylene copolymer was carried out using a liquid-phase polymerization reactor equipped with a stirrer. The prepolymerized catalyst prepared above was slurried with hexane solvent to a concentration of 12 wt %, and the catalyst slurry was continuously fed to the polymerization reactor at a rate of 31.4 kg / hr. Liquid propylene was continuously fed to the polymerization reactor at 22 T / hr, ethylene at 28.5 kg / hr, hydrogen at 0.36 kg / hr, and triisobutylaluminum at 2.2 kg / hr. The internal temperature was maintained at 70°C, and polymerization was carried out. The average catalyst residence time in the polymerization reactor was 1.7 hours. The polymer was continuously withdrawn from the polymerization reactor, and ethanol was fed at a rate of 1.0 kg / hr to deactivate the catalyst. The polymer was then transferred to a degassing process, where it was separated from the gas, and subsequently dried in a drying process. The analysis results of the obtained (a-1) are shown in Table 2.

[0095] (2) Production Example 2 (Production of a-2) (a) Preparation of solid components A 10 L autoclave equipped with a stirrer was thoroughly purged with nitrogen, and 2 L of purified toluene was introduced. 200 g of Mg(OEt)2 and 1 L of TiCl4 were added at room temperature. The temperature was raised to 90°C, and 50 mL of di-n-butyl phthalate was added. The temperature was then raised to 110°C and the reaction was carried out for 3 hours. The reaction product was thoroughly washed with purified toluene. Next, purified toluene was introduced to adjust the total liquid volume to 2 L. 1 L of TiCl4 was added at room temperature, and the temperature was raised to 110°C and the reaction was carried out for 2 hours. The reaction product was thoroughly washed with purified toluene. Next, purified toluene was introduced to adjust the total liquid volume to 2 L. 1 L of TiCl4 was added at room temperature, and the temperature was raised to 110°C and the reaction was carried out for 2 hours. The reaction product was thoroughly washed with purified toluene. Next, purified toluene was introduced to adjust the total liquid volume to 2 L. 1 L of TiCl4 was added at room temperature, and the temperature was raised to 110°C and the reaction was carried out for 2 hours. The reaction product was thoroughly washed with purified toluene. Furthermore, purified n-heptane was used to replace toluene with n-heptane, yielding a slurry of solid component (A1). A portion of this slurry was sampled and dried. Analysis revealed that the Ti content of solid component (A1) was 2.7% by mass. Next, a 20 L autoclave equipped with a stirrer was thoroughly purged with nitrogen, and 100 g of the above slurry of solid component (A1) was introduced as solid component (A1). Purified n-heptane was introduced to adjust the concentration of solid component (A1) to 25 g / L. 50 ml of SiCl4 was added, and the reaction was carried out at 90°C for 1 hour. The reaction product was thoroughly washed with purified n-heptane. Subsequently, purified n-heptane was introduced to adjust the liquid level to 4 L. To this mixture were added 30 ml of dimethyldivinylsilane, 30 ml of (i-Pr)2Si(OMe)2, and 80 g of Et3Al diluted in n-heptane (as Et3Al), and the reaction was carried out at 40°C for 2 hours. The reaction product was thoroughly washed with purified n-heptane, and a portion of the resulting slurry was sampled and dried. Analysis revealed that the solid component contained 1.2 mass% Ti and 8.8 mass% (i-Pr)2Si(OMe)2.

[0096] (b) Prepolymerization The solid component obtained above was used for prepolymerization according to the following procedure. Purified n-heptane was added to the slurry to adjust the solid component concentration to 20 g / L. After cooling the slurry to 10 °C, 10 g of EtAl diluted in n-heptane was added as EtAl, and 280 g of propylene was fed over 4 hours. After the propylene feed was completed, the reaction was continued for another 30 minutes. Next, the gas phase was thoroughly purged with nitrogen, and the reaction product was thoroughly washed with purified n-heptane. The resulting slurry was removed from the autoclave and vacuum-dried to obtain solid catalyst (A). This solid catalyst (A) contained 2.5 g of polypropylene per 1 g of solid component. Analysis revealed that the portion of solid catalyst (A) excluding polypropylene contained 1.0 mass% Ti and 8.2 mass% (i-Pr)2Si(OMe)2.

[0097] (c) Polymerization of propylene The process will be explained using the flow sheet shown in Figure 2. A gas-phase polymerization reactor using two polymerization vessels was used. The two polymerization vessels 1 and 10 had an inner diameter D of 340 mm, a length L of 1260 mm, a diameter of the rotating shaft of 90 mm, and an internal volume of 110 dm 3The reactor was a continuous horizontal gas-phase polymerization reactor (length / diameter = 3.7) equipped with an agitator. After purging the interior of the polymerization vessel 1, 25 kg of polypropylene powder (average particle size 1500 μm) from which polymer particles smaller than 500 μm had been removed was introduced. The solid catalyst (A) obtained above was continuously fed into the polymerization vessel 1 as an n-hexane slurry. The feed rate of the solid catalyst (A) was adjusted so that the production rate of a propylene-ethylene random copolymer was constant. A 15 mass% n-hexane solution of triethylaluminum was continuously fed so that the molar ratio per mole of Ti atom in the solid catalyst (A) was 100. Hydrogen was fed into the polymerization vessel 1 so that the ratio of hydrogen to propylene concentration was 0.031, ethylene was fed so that the ratio of ethylene to propylene concentration was 0.017, and propylene monomer was fed into the polymerization vessel 1 so that the pressure inside the polymerization vessel 1 was maintained at 2.2 MPa and the temperature inside the polymerization vessel 1 was maintained at 65°C. Unreacted gas discharged from the polymerization reactor 1 was withdrawn outside the polymerization reactor system through unreacted gas withdrawal line 4, cooled, condensed, and separated into liquefied propylene and a mixed gas. The mixed gas was returned to the polymerization reactor 1 through recycle gas line 2. Hydrogen gas and ethylene were also supplied through line 2. Liquefied propylene condensed outside the polymerization reactor system was supplied together with fresh raw propylene through raw material mixed gas line 3. The heat of polymerization was removed by the heat of vaporization of the liquefied propylene supplied through line 3. The polypropylene produced in the polymerization reactor 1 was continuously withdrawn from the polymerization reactor 1 through polymer withdrawal line 5 so that the polymer retention level was 50% by volume of the reaction volume and supplied to the polymerization reactor 10 for the second polymerization step. The polymer from the first polymerization step and the mixed gas were continuously supplied to the polymerization reactor 10, and copolymerization of propylene and ethylene was carried out. The reaction conditions were a temperature of 70°C and a pressure of 2.0 MPa. The unreacted gas discharged from the polymerization vessel 10 was withdrawn to the outside of the polymerization vessel system through the unreacted gas withdrawal pipe 8, where it was cooled and condensed to separate into liquefied propylene and a mixed gas. The mixed gas was returned to the polymerization vessel 10 through the recycle gas pipe 7. Hydrogen gas and ethylene were also supplied through the pipe 7. At this time, the ratio of the hydrogen concentration to the propylene concentration and the ratio of the ethylene concentration to the propylene concentration were adjusted to be the same as those in the polymerization vessel 1.Liquefied propylene condensed outside the polymerization reactor system was supplied together with fresh raw material propylene through raw material mixed gas pipe 6. The heat of polymerization was removed by the heat of vaporization of the liquefied propylene supplied through pipe 6. Propylene produced in the second polymerization step was continuously withdrawn from the polymerization reactor 10 through polymer withdrawal pipe 9 so that the polymer retention level was 60% by volume of the reaction volume. Gases were separated from the withdrawn powder in gas recovery unit 12, and the powder portion was withdrawn to the recovery system. The analysis results of the obtained (a-2) are shown in Table 2.

[0098] (3) Production Example 3 (Production of a-3) The polymer was polymerized using the catalyst, polymerization equipment, and polymerization pressure and temperature settings described in JP 2011-148980 A. Hydrogen was continuously supplied as a molecular weight control agent to the first reactor so that the hydrogen / propylene molar ratio was 0.00011, and ethylene was continuously supplied together with propylene so that the ethylene / propylene molar ratio was 0.058. Separately, triisobutylaluminum was supplied at a catalyst rate of 6 g / hr so ​​that the first reactor production rate was 9 kg / h, and powder was withdrawn so that the retention level in the reactor was 50% by volume. The withdrawn powder was subjected to reaction quenching by supplying moisture-containing nitrogen gas, yielding a propylene-ethylene random copolymer. The analysis results of the obtained (a-3) are shown in Table 2.

[0099] 2-2. Propylene polymer (A) (a-1) Propylene-based resin obtained by polymerization in Production Example 1 (a-2) Propylene-based resin obtained by polymerization in Production Example 2 (not subject to the provisions of the present application) (a-3) Propylene-based resin obtained by polymerization in Production Example 3

[0100] TIFF2025124618000013.tif49156

[0101] 2-3. Nucleating agent (B) (b-1) 1,2,3-trideoxy-4,6:5,7-bis-[(4-propylphenyl)methylene]-nonitol, manufactured by Milliken & Company, trade name "Milad NX8000J", a compound represented by formula (1). (Nonitol-based nucleating agent, abbreviated as "NX8000J") (b-2) 1,3:2,4-bis-O-benzylidene-D-sorbitol, manufactured by New Japan Chemical Co., Ltd., trade name "Gelol DXR", a compound represented by formula (2). (Sorbitol-based nucleating agent, abbreviated as "Gelol DXR") (b-3) Sodium salt of 2-hydroxy-2-oxo-4,6,10,12-tetra-tert-butyl-1,3,2-dibenzo[d,g]perhydrodioxaphosphalocin, manufactured by ADEKA Corporation, trade name "ADEGASTABE NA-11", a compound represented by formula (3). (organophosphate nucleating agent, abbreviated as "NA11") (b-4) Mixture of aluminum bis(4,4',6,6'-tetra-tert-butyl-2,2'-methylenediphenyl phosphate) hydroxide (mixture not disclosed) Manufactured by ADEKA Corporation, product name "Adegastab NA-21" The main component is the compound represented by formula (4) (aromatic phosphate ester nucleating agent, abbreviated as "NA21")

[0102] 2-4. Other additives Antioxidant: Tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxylphenyl)propionate]methane, product name "IRGANOX 1010" manufactured by BASF Japan Ltd. (hindered phenol antioxidant, abbreviated as "IR1010") Antioxidant: Tris(2,4-di-t-butylphenyl) phosphite, PEPQ: Tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene-diphosphonite. BASF Japan Ltd. product name "Irgafos 168" (phosphorus antioxidant, abbreviated as "IF168") Neutralizer: Calcium stearate (product name: "Calcium Stearate") manufactured by Nippon Oil & Fats Co., Ltd. (abbreviated as "CAST") Lubricant: Oleic acid amide. Manufactured by Tokyo Chemical Industry Co., Ltd. under the trade name "Oleic acid amide" (abbreviated as "OA") Peroxide: 2,5-di(t-butylperoxy)hexane. NOF Corporation product name: "Perhexa 25B" (abbreviation: "PHA25B")

[0103] 3. Examples 1 to 6 and Comparative Examples 1 to 4 Each polymer and additive were prepared in the blending ratios (parts by weight) shown in Tables 3-1 and 3-2, dry-blended in a Super Mixer, and then melt-kneaded and pelletized in a Toshiba Machine TEM-35B twin-screw extruder at a die outlet temperature of 220°C under a nitrogen atmosphere. The resulting pellets were evaluated according to the evaluation methods described above. The evaluation results are shown in Tables 3-1 and 3-2.

[0104] JPEG2025124618000014.jpg195170

[0105] JPEG2025124618000015.jpg165169

[0106] [Examples and Comparative Examples] As is clear from the table, Example 1 uses the propylene-based resin composition of the present invention, and is a material that is free from sink marks, has a good appearance, and is excellent in moldability, rigidity (flexural modulus), impact resistance (Charpy impact strength), and color development (transparency). Examples 2 to 4 use propylene-based resin compositions of the present invention in which the type of nucleating agent (B) is changed. These materials have no sink marks, a good appearance, and are excellent in moldability, rigidity (flexural modulus), impact resistance (Charpy impact strength), and color development (transparency). Example 5 is within the scope of the present invention, but has a lower MFR, and the ethylene content, molecular weight distribution (Mw / Mn) value, and spiral flow ratio P / D were changed. However, it was found that there were no sink marks, the appearance was good, and the moldability, rigidity (flexural modulus), impact resistance (Charpy impact strength), and color development (transparency) were excellent. Although Example 6 has a relatively high MFR, it is within the range of the present invention, with no sink marks, a good appearance, and excellent moldability, rigidity (flexural modulus), impact resistance (Charpy impact strength), and color development (transparency). In Comparative Example 1, no nucleating agent was added, and therefore sink marks occurred; in Comparative Example 2, a nucleating agent was added, but the molecular weight distribution (Mw / Mn) value and spiral flow ratio P / D were outside the ranges specified in the present invention, and therefore sink marks occurred; and in Comparative Example 3, the molecular weight distribution (Mw / Mn) value and spiral flow ratio P / D were outside the ranges specified in the present invention, and no nucleating agent was added, and therefore sink marks occurred. Comparative Example 4 has a high MFR and is outside the range of the present invention, and although a molded product without sink marks was obtained, burrs were generated on the molded product, and the appearance was poor.

Claims

1. A method for producing a molded article, characterized in that, when injection molding is performed using a pin gate mold satisfying the following condition (X1), a propylene-based resin composition for pin gate mold injection molding is used, the propylene-based resin composition containing a propylene-based polymer (A) satisfying the following conditions (A1) and (A2) and a nucleating agent (B) satisfying the following condition (B1), and satisfying the following (requirements 1) to (requirements 3): Condition (X1) The inner diameter of the pin gate of the pin gate mold is in the range of 0.1 to 1.5 mm. Condition (A1) The propylene polymer (A) is at least one selected from the group consisting of propylene homopolymers, propylene random copolymers, and propylene block copolymers. Condition (A2) The melt flow rate of the propylene polymer (A) (according to JIS K7210, 230° C., 2.16 kg load) is in the range of 5 to 100 g / 10 min. Condition (B1) The nucleating agent (B) is at least one selected from the group consisting of nonitol-based nucleating agents, sorbitol-based nucleating agents, organic phosphate-based nucleating agents, and aromatic phosphate ester-based nucleating agents. (Requirement 1) The propylene-based resin composition for pin-gate mold injection molding contains 0.01 to 1 part by weight of a nucleating agent (B) based on 100 parts by weight of a propylene-based polymer (A). (Requirement 2) The molecular weight distribution (Mw / Mn) of the propylene-based resin composition for pin gate mold injection molding is in the range of 1.1 to 4.

5. (Requirement 3) In the spiral flow (flow length (cm) during injection molding at 200°C in a 2 mm-thick spiral mold) of the propylene-based resin composition for pin-gate mold injection molding, the ratio (P / D) of the flow length P cm at a pin gate (inner diameter 0.6 mm) to the flow length D cm at a direct gate (inner diameter 8 mm) is 0.70 or more.

2. The method for producing a molded article according to claim 1, wherein the propylene polymer (A) further satisfies the following condition (A3): Condition (A3) The propylene polymer (A) is a random copolymer of an α-olefin and propylene, and the content of the α-olefin is 12% by weight or less (provided that the total of the α-olefin and propylene is 100% by weight).

3. A molded article obtained by the method for producing a molded article according to claim 1 or 2.

4. A propylene-based resin composition for pin-gate mold injection molding, which is used in injection molding using a pin-gate mold satisfying the following condition (X1), contains a propylene-based polymer (A) satisfying the following conditions (A1) and (A2) and a nucleating agent (B) satisfying the following condition (B1), and satisfies the following (requirements 1) to (requirements 3): Condition (X1) The inner diameter of the pin gate of the pin gate mold is in the range of 0.1 to 1.5 mm. Condition (A1) The propylene polymer (A) is at least one selected from the group consisting of propylene homopolymers, propylene random copolymers, and propylene block copolymers. Condition (A2) The melt flow rate of the propylene polymer (A) (according to JIS K7210, 230° C., 2.16 kg load) is in the range of 5 to 100 g / 10 min. Condition (B1) The nucleating agent (B) is at least one selected from the group consisting of nonitol-based nucleating agents, sorbitol-based nucleating agents, organic phosphate-based nucleating agents, and aromatic phosphate ester-based nucleating agents. (Requirement 1) The propylene-based resin composition for pin-gate mold injection molding contains 0.01 to 1 part by weight of a nucleating agent (B) based on 100 parts by weight of a propylene-based polymer (A). (Requirement 2) The molecular weight distribution (Mw / Mn) of the propylene-based resin composition for pin gate mold injection molding is in the range of 1.1 to 4.

5. (Requirement 3) In the spiral flow (flow length (cm) during injection molding at 200°C in a 2 mm-thick spiral mold) of the propylene-based resin composition for pin-gate mold injection molding, the ratio (P / D) of the flow length P cm at a pin gate (inner diameter 0.6 mm) to the flow length D cm at a direct gate (inner diameter 8 mm) is 0.70 or more.

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