Propylene-based resin composition and production method therefor

Abstract

[Problem] To provide: a propylene-based resin composition from which a molded article having excellent low-glossiness, surface smoothness, scratch resistance, and mechanical properties can be produced; and a production method therefor. [Solution] Provided are: a propylene-based resin composition comprising a propylene-based block copolymer (A), polyethylene (B), an ethylene / α-olefin copolymer (C), an inorganic filler (D), and a lubricant (E), and characterized in that the contents of the respective components are 40-85 parts by mass for (A), 2-30 parts by mass for (B), 2-25 parts by mass for (C), and 5-30 parts by mass for (D), the content of (E) is 0.1-3.0 parts by mass with respect to 100 parts by mass of the total amount of (A), (B), (C), and (D), and the ratio ηB / ηA of the viscosity ηB (Pa∙s) of (B) to the viscosity ηA (Pa∙s) of (A) is 3.3-4.9; and a production method therefor.

Description

Propylene-based resin composition and method for producing the same

[0001] The present invention relates to a propylene-based resin composition capable of providing an injection-molded article having low gloss, surface smoothness and excellent scratch resistance, and a method for producing the same.

[0002] Polyolefins are widely used in a variety of applications, including automobile and home appliance parts, due to their excellent mechanical properties, moldability, and economical efficiency.

[0003] Injection molded products for these applications use polypropylene alone, or alternatively, rubber components such as ethylene-propylene copolymer (EPR), ethylene-butene copolymer (EBR), ethylene-octene copolymer (EOR), styrene-butadiene copolymer (SBR), polystyrene-ethylene / butene-polystyrene triblock copolymer (SEBS) are added to polypropylene to improve impact resistance, and inorganic fillers such as talc, mica, and glass fiber are also added to improve rigidity.

[0004] In recent years, the appearance of polypropylene has been improved to reduce flow marks (toray marks) and weld marks, and the demand for polypropylene for automobile parts is increasing.

[0005] On the other hand, automotive interior parts such as instrument panels and console boxes, which require high design quality, often undergo post-processing such as painting the surface or laminating a skin.Even if polypropylene injection-molded products do not require such post-processing, if they have high design quality, their excellent economic benefits are expected to lead to further demand growth.

[0006] Therefore, technological development is being conducted to prevent the occurrence of tiger stripes, welds, etc. on the surface of injection-molded products and improve their surface properties. This has also been attempted to reduce the number of post-processing steps for automotive interior parts that require high design quality, but the scratch resistance of the surface is sometimes insufficient and the high gloss has not led to a reduction in post-processing steps for parts that require particularly high surface properties, such as instrument panels and console boxes.

[0007] Thus, it has become an even greater challenge than before to improve the low gloss and surface smoothness of polypropylene injection-molded articles, as well as to improve their scratch resistance so as to be able to withstand instantaneous scratches caused by external influences, and their mechanical properties so as to be able to withstand long-term use.

[0008] Patent Documents 1 to 3 disclose techniques for polypropylene resin compositions having a viscosity that satisfies specific conditions.

[0009] JP-A-10-330579 Patent No. 4023859 JP-A 8-165400

[0010] However, the techniques proposed in these patent documents do not recognize the problems of improving the low gloss appearance and surface smoothness of injection-molded articles, and improving scratch resistance and mechanical properties that enable them to withstand long-term use.

[0011] Means for Solving the Problems The present inventors have conducted extensive research to solve the above problems and have found a propylene-based resin composition that can provide a molded article having low gloss, surface smoothness, scratch resistance, and excellent mechanical properties, thereby completing the present invention.

[0012] The present invention includes the following aspects.

[0013] [1] A propylene-based resin composition comprising a propylene-based block copolymer (A), a polyethylene (B), an ethylene-α-olefin copolymer (C), an inorganic filler (D), and a lubricant (E), wherein the respective amounts of the copolymers are 40 to 85 parts by mass for (A), 2 to 30 parts by mass for (B), 2 to 25 parts by mass for (C), and 5 to 30 parts by mass for (D) (where the total of (A), (B), (C), and (D) is 100 parts by mass), and further, the amount of (E) is 0.1 to 3.0 parts by mass per 100 parts by mass of the total of (A), (B), (C), and (D), and the ratio ηB / ηA of the viscosity ηA (Pa s) of (A) to the viscosity ηB (Pa s) of (B) is 3.3 to 4.9 (where the viscosities ηA and ηB are measured at a temperature of 200°C and a shear rate of 1216 (1 / sec)).

[0014] [2] The density of the polyethylene (B) is 930 to 965 kg / m ３ The propylene-based resin composition according to the above [1],

[0015] [3] The propylene-based resin composition according to either [1] or [2] above, wherein the polyethylene (B) has a melt mass flow rate (MFR, 230°C, load 2.16 kg) of 0.08 to 1.0 g / 10 min.

[0016] [4] The density of the ethylene / α-olefin copolymer (C) is 880 kg / m ３ The propylene-based resin composition according to any one of [1] to [3] above, which is:

[0017] [5] The propylene-based resin composition according to any one of [1] to [4] above, wherein the ethylene-α-olefin copolymer (C) has a melt mass flow rate (MFR, 230°C, load 2.16 kg) in the range of 0.1 to 5.0 g / 10 min.

[0018] [6] The propylene-based resin composition according to any one of [1] to [5] above, wherein the propylene-based resin composition has a melt mass flow rate (MFR, 230°C, load 2.16 kg) of 10 to 50 g / 10 min.

[0019] [7] A molded article made of the propylene-based resin composition according to any one of [1] to [6] above.

[0020] [8] A method for producing the propylene-based resin composition according to any one of the above [1] to [6], characterized by melt-kneading a propylene-based block copolymer (A), a polyethylene (B), an ethylene-α-olefin copolymer (C), an inorganic filler (D), and a lubricant (E).

[0021] Injection molded articles obtained from the propylene-based resin composition of the present invention are excellent in appearance, scratch resistance and mechanical properties, and are therefore useful in many applications.

[0022] The present invention will be specifically described below, but the present invention is not limited to these embodiments.

[0023] The present invention provides a propylene-based resin composition comprising a propylene-based block copolymer (A), a polyethylene (B), an ethylene-α-olefin copolymer (C), an inorganic filler (D), and a lubricant (E), wherein the amounts of the above components are 40 to 85 parts by mass for (A), 2 to 30 parts by mass for (B), 2 to 25 parts by mass for (C), and 5 to 30 parts by mass for (D) (where the total of (A), (B), (C), and (D) is 100 parts by mass), and further, the amount of (E) is 0.1 to 3.0 parts by mass per 100 parts by mass of the total of (A), (B), (C), and (D), and the ratio ηB / ηA of the viscosity ηA (Pa s) of (A) to the viscosity ηB (Pa s) of (B) is 3.3 to 4.9 (where the viscosities ηA and ηB are measured at a temperature of 200°C and a shear rate of 1216 (1 / sec)).

[0024] The propylene-based block copolymer (A), polyethylene (B), ethylene-α-olefin copolymer (C), inorganic filler (D), and lubricant (E) that constitute the composition of the present invention will be described below.

[0025] <<Propylene-Based Block Copolymer (A)>> The propylene-based block copolymer (A) preferably has a melt mass flow rate (MFR, 230°C, load 2.16 kg) measured according to a method in accordance with JIS K 7210 (ISO 1133) in the range of 2 to 300 g / 10 min. The lower limit of MFR is more preferably 3 g / 10 min, even more preferably 5 g / 10 min, even more preferably 8 g / 10 min, particularly preferably 10 g / 10 min, and most preferably 11 g / 10 min. The upper limit is more preferably 250 g / 10 min, even more preferably 200 g / 10 min, even more preferably 150 g / 10 min, particularly preferably 100 g / 10 min, and most preferably 60 g / 10 min. The MFR is desirably equal to or less than the upper limit value from the viewpoint of strand take-up property during melt-kneading of the propylene-based resin composition, and is desirably equal to or more than the lower limit value from the viewpoint of filling property during injection molding of the composition.

[0026] The melting point of the propylene-based block copolymer (A) is preferably 150° C. or higher, and more preferably 150 to 170° C. When the melting point is in this range, the propylene-based resin composition of the present invention has excellent rigidity and heat resistance.

[0027] The propylene block copolymer (A) generally comprises a propylene polymer portion (A1) mainly composed of propylene and a propylene-α-olefin copolymer portion (A2) mainly composed of propylene and an α-olefin (excluding propylene).

[0028] Propylene Polymer Segment (A1) The propylene polymer segment (A1) preferably contains 98 to 100 mol % of structural units derived from propylene, and preferably contains 0 to 2 mol % of structural units derived from at least one α-olefin selected from α-olefins having 2 to 8 carbon atoms (excluding propylene) (provided that the total of the structural units derived from propylene and the structural units derived from the α-olefin is 100 mol %).

[0029] The propylene polymer portion (A1) is １３The mesopentad fraction (mmmm) determined by C-NMR is usually 90.0 to 100%, preferably 95.0 to 100%, and more preferably 97.0 to 100%. The upper limit of mmmm may be 99.9% or 99.5%. When mmmm is greater than the lower limit, the heat resistance is good.

[0030] The propylene polymer portion (A1) generally corresponds to the n-decane insoluble component of the propylene block copolymer at 23° C., and is a component that is mainly composed of a crystalline polypropylene resin and is considered to exhibit high rigidity.

[0031] Propylene / α-olefin copolymer portion (A2) The propylene / α-olefin copolymer portion (A2) preferably contains 40.0 to 90.0 mol %, particularly 50.0 to 90.0 mol %, and of these, 55.0 to 85.0 mol % of structural units derived from propylene, and the proportion of structural units derived from at least one α-olefin selected from α-olefins having 2 to 20 carbon atoms (excluding propylene) is preferably 10.0 to 60.0 mol %, particularly 10.0 to 50.0 mol %, and of these, 15.0 to 45.0 mol % (wherein the total of the structural units derived from propylene and the structural units derived from the α-olefin is 100 mol %).

[0032] Examples of the α-olefins having 2 to 20 carbon atoms (excluding propylene) include ethylene, 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, and 1-eicosene, with ethylene being preferred. These may be used alone or in combination of two or more.

[0033] This content ratio can be determined by, for example, carbon nuclear magnetic resonance analysis ( １３ It can be measured by C-NMR.

[0034] The propylene / α-olefin copolymer portion (A2) has an intrinsic viscosity [η] measured with decalin at 135°C of usually 1.0 to 12 dL / g, preferably 1.5 to 11 dL / g, and more preferably 1.5 to 8 dL / g.

[0035] The propylene / α-olefin copolymer portion (A2) generally corresponds to the component of the propylene-based block copolymer that is soluble in n-decane at 23°C.

[0036] In the present invention, the propylene-based block copolymer (A) has a propylene polymer portion (A1) content of 50 to 99% by mass, preferably 60 to 99% by mass, and more preferably 70 to 95% by mass, and a propylene-α-olefin copolymer portion (A2) content of 1 to 50% by mass, preferably 1 to 40% by mass, and more preferably 5 to 30% by mass (where the total of (A1) and (A2) is 100% by mass).

[0037] By using the propylene-based block copolymer (A) in the propylene-based resin composition of the present invention, it is possible to form a molded article having an excellent balance between heat resistance, rigidity, and impact resistance.

[0038] The propylene block copolymer (A) may be used alone or in combination of two or more.

[0039] Method for Producing Propylene-Based Block Copolymer (A) The method for producing the propylene-based block copolymer (A) is not particularly limited. For example, the propylene-based block copolymer (A) can be produced by continuously polymerizing the propylene polymer portion (A1) (polymerization step 1) and the propylene-α-olefin copolymer portion (A2) (polymerization step 2) in multiple stages in the presence of a Ziegler-Natta catalyst or a metallocene catalyst.

[0040] As described above, the propylene polymer portion (A1) corresponds to a component insoluble in n-decane at 23° C., is composed mainly of a crystalline polypropylene resin, and is a component that is considered to impart high rigidity to the propylene block copolymer (A). The propylene / α-olefin copolymer portion (A2) generally corresponds to a component soluble in n-decane at 23° C. and is a component that is considered to impart impact resistance to the propylene block copolymer (A).

[0041] The physical properties of the propylene-based block copolymer (A) can be adjusted by adjusting the individual monomer configurations, molecular weights, molecular weight distributions, and further the ratio of (A1) to (A2) produced, of these (A1) and (A2).

[0042] Examples of the catalysts used in these processes include those described in JP-A-2014-214202, JP-A-2016-084387, WO 2019 / 004418, and JP-A-2007-224179.

[0043] Furthermore, with regard to the production conditions of the propylene-based block copolymer (A), these publications, for example, paragraphs

[0053] to

[0077] of JP-A-2014-214202, paragraphs

[0052] to

[0075] of JP-A-2016-084387, and paragraphs

[0100] to

[0110] of WO 2019 / 004418 can be referenced.

[0044] The polymerization in each stage may be carried out by any of gas phase polymerization, solution polymerization, suspension polymerization, or other liquid phase polymerization methods, or may be carried out by different methods in each stage. The polymerization may be carried out either continuously or semi-continuously, and each stage may be carried out in a plurality of polymerization vessels, for example, 2 to 10 polymerization vessels.

[0045] In this case, it is preferable to carry out the second and subsequent polymerization stages in two or more separate polymerization vessels, which makes it possible to prevent the generation of gel.

[0046] As the polymerization medium, an inert hydrocarbon may be used, or liquid propylene may be used. The polymerization conditions for each stage are appropriately selected from the polymerization temperature range of about −50 to +200° C., preferably about 20 to 100° C., and the polymerization pressure range of normal pressure to 10 MPa (gauge pressure), preferably about 0.2 to 5 MPa (gauge pressure).

[0047] The propylene-based block copolymer (A) can be obtained, for example, by continuously carrying out the following two steps ([polymerization step 1] and [polymerization step 2]) in a reactor having two or more polymerization vessels connected in series. When producing the propylene-based block copolymer (A), [polymerization step 1] may be carried out in each polymerization vessel using a polymerization vessel having two or more reactors connected in series, or [polymerization step 2] may be carried out in each polymerization vessel using a polymerization vessel having two or more reactors connected in series. Alternatively, [polymerization step 1] and [polymerization 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-based block copolymer (A).

[0048] Hereinafter, a method for producing the propylene-based block copolymer (A) by successively carrying out [polymerization step 1] and [polymerization step 2] will be described.

[0049] [Polymerization step 1] is a step of producing a propylene polymer (A1) by polymerizing propylene, for example, at a polymerization temperature of 0 to 100° C. and a polymerization pressure of normal pressure to 5 MPa gauge pressure. In order to obtain a molded product excellent in rigidity, it is preferable to polymerize only propylene, and if necessary, a chain transfer agent such as hydrogen gas may be introduced to adjust the molecular weight, intrinsic viscosity, etc. of the polymer produced in [polymerization step 1].

[0050] [Polymerization step 2] is a step of copolymerizing propylene and an α-olefin (e.g., 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-α-olefin copolymer (elastomer) is produced by increasing the ratio of the feed amount of the α-olefin (e.g., ethylene) to the feed amount of propylene compared to that in [polymerization step 1]. If necessary, a chain transfer agent such as hydrogen gas may also be introduced to adjust the molecular weight, intrinsic viscosity, etc. of the polymer produced in [polymerization step 2].

[0051] The propylene-based block polymer (A) is obtained by continuously carrying out the above-mentioned [Polymerization Step 1] and [Polymerization Step 2], and 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 [Polymerization Step 1]) when carrying out [Polymerization Step 1] or [Polymerization Step 2]. That is, the molecular weight can be adjusted by increasing this ratio. Furthermore, in [Polymerization Step 2], the molecular weight can be adjusted by adjusting the ratio of the feed amount of hydrogen gas as a chain transfer agent to the feed amounts of propylene and α-olefin (e.g., ethylene).

[0052] In addition to the above-mentioned method, the molecular weight can be adjusted by melt-kneading the propylene polymer obtained by polymerization in the presence of an organic peroxide. By melt-kneading the propylene polymer obtained by polymerization in the presence of an organic peroxide, the molecular weight can be reduced.

[0053] By adjusting the polymerization times in [Polymerization step 1] and [Polymerization step 2], the ratio of the propylene polymer portion (A1) to the propylene-α-olefin copolymer portion (A2) can be adjusted.

[0054] The monomer ratio of the propylene-α-olefin copolymer portion (A2) can be adjusted by adjusting the ratio of the amount of α-olefin (for example, ethylene) fed to the amount of propylene fed when carrying out [polymerization step 2].

[0055] The molecular weight of the propylene-α-olefin copolymer portion (A2) can be adjusted by adjusting the feed amount of hydrogen gas used as a chain transfer agent in carrying out [polymerization step 2]. That is, the molecular weight can be reduced by increasing the ratio of the feed amount of hydrogen gas to the feed amount of monomer (i.e., propylene and α-olefin (ethylene)), and the molecular weight can be increased by decreasing the ratio of the feed amount of hydrogen gas to the feed amount of monomer.

[0056] After the polymerization is completed, if necessary, a known catalyst is activated, and post-treatments such as removal of catalyst residue and drying are carried out, whereby the propylene-based block polymer (A) is obtained as a powder.

[0057] In addition, if a commercially available product is available as the propylene-based block copolymer (A), it may be used.

[0058] The propylene-based block copolymer (A) used in the present invention may contain biomass-derived propylene. The propylene constituting the polymer may be solely biomass-derived propylene, or may contain both biomass-derived propylene and fossil fuel-derived propylene.

[0059] Biomass-derived propylene is propylene made from any renewable natural raw material or its residue, such as plant or animal origin, including fungi, yeast, algae, and bacteria, and contains 14C isotopes as carbon. -１２ The propylene homopolymer according to the present invention preferably contains biomass-derived propylene in a proportion of about 100 pMC, and has a biomass carbon concentration (pMC) of about 100 pMC as measured in accordance with ASTM D 6866. Biomass-derived propylene can be obtained by a conventionally known method. It is preferable that the propylene homopolymer according to the present invention contains biomass-derived propylene from the viewpoint of reducing the environmental load (mainly greenhouse gas emissions). If the polymer production conditions, such as the polymerization catalyst, polymerization process, and polymerization temperature, are the same, even if the raw material propylene contains biomass-derived propylene, the propylene homopolymer according to the present invention can be obtained by converting the 14C isotope to 10 -１２ ~10 -１４ Other than the proportion of propylene in the polymer, its molecular structure is the same as that of propylene homopolymer, which is made from fossil fuel-derived propylene. Therefore, its performance is said to be the same.

[0060] The propylene-based block copolymer (A) used in the present invention may contain chemically recycled propylene. The propylene constituting the polymer may consist solely of chemically recycled propylene, or may contain chemically recycled propylene together with fossil fuel-derived propylene and / or biomass-derived propylene. Chemically recycled propylene can be obtained by a conventionally known method. It is preferable that the propylene-based block copolymer (A) used in the present invention contain chemically recycled propylene from the viewpoint of reducing environmental impact (mainly waste reduction). Even if the raw material monomer contains a chemically recycled monomer, the chemically recycled monomer is a monomer obtained by depolymerizing or pyrolyzing a polymer such as waste plastic back into a monomer unit such as propylene, or a monomer produced using such a monomer as a raw material. Therefore, if the polymer production conditions, such as the polymerization catalyst, polymerization process, and polymerization temperature, are equivalent, the molecular structure will be equivalent to that of a propylene-based block copolymer made from a fossil fuel-derived monomer. Therefore, the performance is also considered to be unchanged.

[0061] <<Polyethylene (B)>> The polyethylene used in the present invention preferably has a melt mass flow rate (MFR, 230°C, load 2.16 kg) measured by a method in accordance with JIS K 7210 (ISO 1133) of 1.0 g / 10 min or less.

[0062] From the viewpoint of reducing the number of surface defects in the appearance of a molded article of the composition, the lower limit of the MFR is more preferably 0.01 g / 10 min, even more preferably 0.03 g / 10 min, even more preferably 0.06 g / 10 min, and most preferably 0.1 g / 10 min, and the upper limit is more preferably 0.9 g / 10 min, even more preferably 0.8 g / 10 min, even more preferably 0.7 g / 10 min, and most preferably 0.6 g / 10 min.

[0063] The polyethylene (B) has a density of 920 to 970 kg / m ３ , among which 930 to 965 kg / m ３ It is also preferable that the density is 945 to 965 kg / m３ is more preferably 950 to 965 kg / m ３ The polyethylene (B) preferably has an MFR (230° C., load 2.16 kg) of 1.0 g / 10 min or less, more preferably 0.08 to 1.0 g / 10 min.

[0064] The polyethylene (B) is composed mainly of structural units derived from ethylene, and is a homopolymer of ethylene or a copolymer obtained by copolymerizing structural units derived from ethylene with an α-olefin other than ethylene.

[0065] The proportion of structural units derived from ethylene in the polyethylene (B) is 98.0 to 100.0 mol%, preferably 99.0 to 100.0 mol%, and the proportion of structural units derived from at least one α-olefin selected from α-olefins having 2 to 20 carbon atoms (excluding ethylene) is 0 to 2.0 mol%, preferably 0 to 1.0 mol% (where the total of the structural units derived from ethylene and the structural units derived from the α-olefin is taken as 100 mol%).

[0066] The polyethylene (B) used in the present invention can be selected from, for example, ethylene homopolymers produced by known medium-low pressure processes, and copolymers of ethylene with comonomers such as propylene and butene-1. Examples of such resins include high-density polyethylene resins and medium-density polyethylene resins. Two or more of these may be used in combination depending on the desired physical properties. Commercially available products may also be used.

[0067] For example, HI-ZEX (registered trademark) 3000B, 5100B, 5202B, 520MB, 6008B, 6203B, 6700B, 8200B, 8800B, 5000S, 5000SR, 5000SF, 6800S, 5000H, 6300M, 5100E, 5305E, 7700M, 7800M, etc. manufactured by Prime Polymer Co., Ltd. may be appropriately selected and used while taking into consideration the value of ηB / ηA and the value of MFR (230°C) in the composition.

[0068] <<Ethylene / α-olefin copolymer (C)>> The ethylene / α-olefin copolymer (C) used in the present invention is a copolymer of ethylene and an α-olefin having 3 to 10 carbon atoms, and is usually a random copolymer.

[0069] Examples of structural units derived from an α-olefin having 3 to 8 carbon atoms that constitute the ethylene / α-olefin copolymer (C) include propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene. The α-olefins may be used alone or in combination of two or more. Of these, 1-butene, 1-hexene, and 1-octene are preferred. As the ethylene / α-olefin copolymer (C), ethylene / 1-octene copolymer and ethylene / 1-butene copolymer are particularly preferred.

[0070] The ethylene content of the ethylene / α-olefin copolymer (C) is preferably 70 to 95 mol %, more preferably 75 to 95 mol %.

[0071] The melt mass flow rate (MFR, 230°C, 2.16 kg load) of the ethylene / α-olefin copolymer (C) is preferably 0.01 to 10 g / 10 min, more preferably 0.05 to 7 g / 10 min, and of these, preferably 0.1 to 5 g / 10 min.

[0072] From the viewpoint of impact resistance, the lower limit is preferably 0.1 g / 10 min, more preferably 0.2 g / 10 min, particularly preferably 0.3 g / 10 min, and most preferably 0.4 g / 10 min.

[0073] From the viewpoint of dispersibility, the upper limit is preferably 5 g / 10 min, more preferably 4 g / 10 min, even more preferably 3 g / 10 min, particularly preferably 2 g / 10 min, and most preferably 1 g / 10 min.

[0074] The MFR can be measured by a method in accordance with JIS K 7210 (ISO 1133).

[0075] The density of the ethylene-α-olefin copolymer (C) has a lower limit of 0.85 g / cm3 from the viewpoint of impact resistance. ３is preferable, and more preferably 0.855 g / cm ３ , more preferably 0.86 g / cm ３ The upper limit is 0.9 g / cm ３ is preferable, and more preferably 0.89 g / cm ３ , more preferably 0.88 g / cm ３ , particularly preferably 0.87 g / cm ３ is.

[0076] The ethylene-α-olefin copolymer (C) is a copolymer of ethylene and an α-olefin, and is amorphous or low-crystalline, and is generally called a thermoplastic elastomer, unlike ethylene polymers known as linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE).

[0077] The ethylene / α-olefin copolymer (C) used in the resin composition of the present invention can be produced by various known production methods.

[0078] The polyethylene (B) and ethylene-α-olefin copolymer (C) used in the present invention may contain biomass-derived monomers (ethylene, α-olefin). The monomers constituting the polymer may be biomass-derived monomers only, or may contain both biomass-derived monomers and fossil fuel-derived monomers. The biomass-derived monomer is a monomer obtained from any renewable natural raw material or its residue, such as a plant-derived or animal-derived material, including fungi, yeast, algae, and bacteria, and contains 10 carbon isotopes of 14C. -１２ The biomass-derived monomer is contained in a proportion of about 100 (pMC) as measured in accordance with ASTM D 6866. The biomass-derived monomer is obtained by a conventionally known method. It is preferable that the polyethylene (B) and the ethylene-α-olefin copolymer (C) contain a biomass-derived monomer from the viewpoint of reducing the environmental load (mainly greenhouse gas reduction). If the polymer production conditions such as the polymerization catalyst, polymerization temperature in the polymerization process, etc. are the same, even if the raw material monomer contains a biomass-derived monomer, the 14C isotope can be converted to 10 -１２ ~10 -１４Other than the proportion of ethylene α-olefins in the polymer, its molecular structure is the same as that of ethylene-α-olefin copolymers made from fossil fuel-derived monomers, and its performance is therefore said to be unchanged.

[0079] The polyethylene (B) and the ethylene-α-olefin copolymer (C) used in the present invention may contain a monomer (ethylene, α-olefin) derived from chemical recycling.

[0080] The monomers constituting the polymer may consist solely of chemically recycled monomers, or may contain chemically recycled monomers together with fossil fuel-derived monomers and / or biomass-derived monomers. Chemically recycled monomers can be obtained by conventionally known methods. It is preferable for the ethylene-α-olefin copolymer (A) according to the present invention to contain chemically recycled monomers from the viewpoint of reducing environmental impact (mainly waste reduction). Even if the raw material monomer contains chemically recycled monomers, the chemically recycled monomers are monomers obtained by depolymerizing or pyrolyzing polymers such as waste plastics back into monomer units such as ethylene, or monomers produced using such monomers as raw materials. Therefore, if the polymer production conditions, such as the polymerization catalyst, polymerization process, and polymerization temperature, are equivalent, the molecular structure will be equivalent to that of an ethylene-α-olefin copolymer composed of fossil fuel-derived monomers. Therefore, performance is also considered to be unchanged.

[0081] <<Inorganic Filler (D)>> The inorganic filler (D) used in the resin composition of the present invention can be a known inorganic filler, and examples thereof include aluminum-based (aluminum hydroxide, aluminum silicate), barium-based (barium hydroxide, barium carbonate), calcium-based (calcium carbonate, calcium silicate, calcium sulfate), magnesium-based (magnesium carbonate, magnesia, magnesium silicate, talc, magnesium hydroxide, magnesium sulfate fiber), silica-based (silica, sodium aluminum silicate), zinc-based (zinc oxide), bentonite, clay, diatomaceous earth, ammonium phosphate, carbon black, glass fiber, carbon fiber, and other inorganic fibers.

[0082] Of these, calcium carbonate, talc, silica, clay, and diatomaceous earth are preferred.

[0083] The average particle size (D50) of the inorganic filler (D) used in the present invention can be measured by a laser light diffraction scattering method. From the viewpoint of mechanical properties, the lower limit of the average particle size (D50) of the inorganic filler (D) is preferably 1 μm, more preferably 2 μm, and even more preferably 3 μm. The upper limit is preferably 10 μm, more preferably 8 μm, even more preferably 6 μm, and particularly preferably 5 μm.

[0084] When the inorganic filler (D) is mixed with the resin composition of the present invention, it is preferable to prepare a masterbatch or the like to improve dispersibility in other resins.

[0085] <<Lubricant (E)>> As the lubricant (E) used in the present invention, known lubricants can be used, and examples thereof include fatty acid amides and monoglycerides.

[0086] Specific examples of fatty acid amides include oleic acid amide, stearic acid amide, erucic acid amide, behenic acid amide, palmitic acid amide, myristic acid amide, lauric acid amide, caprylic acid amide, caproic acid amide, n-oleyl palmitamide, n-oleyl erucamide, and dimers thereof, among which oleic acid amide, stearic acid amide, erucic acid amide, and dimers of erucic acid amide are preferred. These can be used alone or in combination.

[0087] <<Proportions of Each Component in Propylene-Based Resin Composition>> The propylene-based resin composition of the present invention contains 40 to 85 parts by mass of (A), 2 to 30 parts by mass of (B), 2 to 25 parts by mass of (C), and 5 to 30 parts by mass of (D) (where the total of (A), (B), (C), and (D) is 100 parts by mass), and further contains 0.1 to 3.0 parts by mass of (E) relative to 100 parts by mass of the total of (A), (B), (C), and (D).

[0088] Proportion of Propylene-Based Block Copolymer (A) In terms of ensuring mechanical properties and flowability, the proportion of the propylene-based block copolymer (A) in the propylene-based resin composition, when the total of (A), (B), (C), and (D) is 100 parts by mass, is preferably 40 parts by mass at the lower limit, more preferably 45 parts by mass, and even more preferably 50 parts by mass at the upper limit, and is preferably 85 parts by mass, more preferably 80 parts by mass, even more preferably 75 parts by mass, and particularly preferably 70 parts by mass at the upper limit.

[0089] Proportion of polyethylene (B): From the viewpoint of the quality of injection-molded articles obtained from the composition, the proportion of polyethylene (B) in the propylene-based resin composition is preferably 2 parts by mass, more preferably 3 parts by mass, and even more preferably 4 parts by mass, where the total of (A), (B), (C), and (D) is 100 parts by mass. From the viewpoint of maintaining the rigidity (flexural modulus) of the mechanical properties, the upper limit is preferably 25 parts by mass, more preferably 20 parts by mass, even more preferably 15 parts by mass, and particularly preferably 10 parts by mass.

[0090] Proportion of Ethylene-α-olefin Copolymer (C) From the viewpoint of maintaining the mechanical rigidity (flexural modulus), the proportion of the ethylene-α-olefin copolymer (C) in the propylene-based resin composition, when the total of (A), (B), (C), and (D) is 100 parts by mass, is preferably 2 parts by mass at its lower limit, more preferably 5 parts by mass, and even more preferably 8 parts by mass at its upper limit. The proportion is preferably 25 parts by mass, more preferably 20 parts by mass, even more preferably 18 parts by mass, and particularly preferably 15 parts by mass at its upper limit.

[0091] Proportion of inorganic filler (D): From the viewpoint of improving rigidity, the proportion of the inorganic filler (D) in the propylene-based resin composition, when the total of (A), (B), (C), and (D) is 100 parts by mass, is preferably 5 parts by mass, more preferably 8 parts by mass, more preferably 10 parts by mass, and particularly preferably 15 parts by mass. From the viewpoint of improving impact resistance, the upper limit is preferably 30 parts by mass, more preferably 28 parts by mass, even more preferably 25 parts by mass, and particularly preferably 20 parts by mass.

[0092] Proportion of Lubricant (E) In terms of scratch resistance, the proportion of the lubricant (E) in the propylene-based resin composition is preferably 0.1 parts by mass, more preferably 0.2 parts by mass, and even more preferably 0.25 parts by mass, relative to 100 parts by mass of the total of (A), (B), (C), and (D). The upper limit is preferably 2 parts by mass, more preferably 1 part by mass, even more preferably 0.5 parts by mass, and particularly preferably 0.4 parts by mass.

[0093] <<Ratio ηB / ηA of Viscosity ηA of (A) to Viscosity ηB of (B)>> The propylene-based resin composition of the present invention and the injection-molded article obtained therefrom are characterized in that the ratio ηB / ηA of the viscosity ηA (Pa s) of component (A) at a temperature of 200°C and a shear rate of 1216 (1 / sec) to the viscosity ηB (Pa s) of component (B) at a temperature of 200°C and a shear rate of 1216 (1 / sec) is in the range of 3.3 to 4.9.

[0094] From the viewpoint of ease of molding, the ratio ηB / ηA has a lower limit of preferably 3.3, more preferably 3.5, and of these, preferably 3.9, and an upper limit of preferably 4.9, more preferably 4.5, and of these, preferably 4.3, and particularly preferably 4.2.

[0095] These viscosities can be evaluated using a capillary rheometer.

[0096] In the propylene-based resin composition of the present invention, by setting the composition within the above-mentioned range, it is possible to achieve both improvements in the appearance and scratch resistance of molded articles and improvements in mechanical properties.

[0097] It is generally known that the viscosity of thermoplastic resins changes depending on the shear rate during melting. If the shear rate is high, the viscosity will be low, and if the shear rate is low, the viscosity will be high. It is also generally known that the viscosity of thermoplastic resins changes depending on the melting temperature. If the melting temperature is low, the viscosity will be high, and if the melting temperature is high, the viscosity will be low.

[0098] Regarding the viscosity ηA of the propylene block copolymer (A) component at a temperature of 200°C and a shear rate of 1216 (1 / sec), from the viewpoint of ensuring mass productivity of melt-kneading, the lower limit is preferably 1 (Pa s), more preferably 5 (Pa s), and of these, preferably 30 (Pa s). The upper limit is preferably 150 (Pa s), more preferably 100 (Pa s), and of these, preferably 80 (Pa s), and particularly preferably 70 (Pa s).

[0099] This viscosity can be adjusted by adjusting the molecular weight distribution when polymerizing the propylene-based block copolymer (A) component, or by controlling the viscosity of the propylene-α-olefin copolymer or the like.

[0100] Viscosity ηB From the viewpoint of obtaining a good appearance of a molded product, the viscosity ηB of the polyethylene (B) component at a temperature of 200°C and a shear rate of 1216 (1 / sec) is preferably 50 (Pa s) in lower limit, more preferably 150 (Pa s), and even more preferably 200 (Pa s). The upper limit is preferably 500 (Pa s), more preferably 400 (Pa s), even more preferably 300 (Pa s), and particularly preferably 280 (Pa s).

[0101] This viscosity can be adjusted by adjusting the molecular weight distribution during polymerization of the polyethylene (B) component, or by controlling the number and length of long chain branches and short chain branches.

[0102] <<Other Components>> The propylene-based resin composition of the present invention may contain other components, such as resins, rubbers, nucleating agents, heat stabilizers, weather stabilizers, antistatic agents, antislip agents, antiblocking agents, antifogging agents, pigments, dyes, plasticizers, antioxidants, hydrochloric acid absorbers, and antioxidants, in addition to the components described above, within the scope of the present invention.

[0103] <<Nucleating Agent>> Examples of nucleating agents include organic nucleating agents such as phosphate-based nucleating agents (organic phosphoric acid metal salts), sorbitol-based nucleating agents, metal salts of aromatic carboxylic acids, metal salts of aliphatic carboxylic acids, and rosin-based compounds; and inorganic nucleating agents such as inorganic compounds.

[0104] Commercially available nucleating agents include, for example, the phosphate-based nucleating agent "ADK STAB NA-11" (manufactured by ADEKA CORPORATION), the sorbitol-based nucleating agent "MILAD NX8000" (manufactured by Milliken), the nucleating agent made of a metal salt of an aliphatic carboxylic acid "HYPERFOAM HPN-20E" (manufactured by Milliken), and the nucleating agent made of a rosin-based compound "Pine Crystal KM1610" (manufactured by Arakawa Chemical Industries, Ltd.).

[0105] The nucleating agent may be used alone or in combination of two or more kinds.

[0106] The content of the nucleating agent in the composition of the present invention is preferably 0.01 to 1 mass %, more preferably 0.02 to 0.8 mass %, and even more preferably 0.03 to 0.5 mass %.

[0107] In the propylene-based resin composition of the present invention, by setting the composition within the above-mentioned range, it is possible to achieve both good appearance, scratch resistance, and mechanical properties of the molded product.

[0108] MFR of Propylene-Based Resin Composition The melt mass flow rate (MFR, 230°C, load 2.16 kg) of the propylene-based resin composition of the present invention is generally 5 to 100 g / 10 min, and it can be molded into molded articles for a wide range of uses.

[0109] In particular, those having a melt mass flow rate (MFR, 230° C., load 2.16 kg) of 10 to 50 g / 10 min are suitable for various injection molding applications.

[0110] <<Method for Producing Propylene-Based Resin Composition>> The method for producing the propylene-based resin composition of the present invention is not particularly limited, and the propylene-based resin composition can be produced by mixing the above-mentioned (A), (B), (C), (D), and (E) and, if necessary, additives, and melt-kneading the mixture. The melt-kneading can be carried out by a commonly used method, for example, a method using a single-screw extruder, a twin-screw extruder, a co-kneader, a multi-screw extruder, or the like. The heating temperature (kneading temperature) during melt-kneading is usually selected appropriately in the range of 160 to 270°C.

[0111] In particular, a method using a twin-screw extruder is preferred as a method for obtaining the propylene-based resin composition of the present invention. As a method for producing the propylene-based resin composition, a method is preferred in which, in addition to the above-mentioned (A), (B), (C), (D), and (E), additives are mixed as necessary, and the mixture is melt-kneaded under conditions of a cylinder temperature (kneading temperature) of 160° C. or higher and 270° C. or lower, and a residence time of 20 seconds or higher and 300 seconds or lower.

[0112] Furthermore, from the viewpoint of obtaining a resin composition having an excellent color tone, it is preferable to continuously supply an inert gas such as nitrogen during melt-kneading to replace the air inside.

[0113] In the present invention, even when polyethylene (B) having a different MFR (230°C) is used, as long as the MFR (230°C) is within a range of, for example, 1 or less, it is possible to stably produce compositions having substantially the same low gloss properties.

[0114] As described above, the method for producing a propylene-based resin composition of the present invention is characterized by melt-kneading the propylene-based block copolymer (A), the polyethylene (B), the ethylene-α-olefin copolymer (C), the inorganic filler (D), and the lubricant (E). In this process, in addition to the components (A), (B), (C), (D), and (E), additives may be present as needed.

[0115] <<Method for molding propylene-based resin composition>> The propylene-based resin composition of the present invention can be processed into molded articles for a wide range of uses. The molded articles may be melt-kneaded products of the resin composition or pellets obtained by melt-kneading. Furthermore, the pellets can be used as a raw material to produce the molded articles by injection molding, injection compression molding, extrusion molding, blow molding, press molding, vacuum molding, foam molding, or the like.

[0116] In particular, it is preferable to use the obtained pellets to produce a molded article by injection molding or injection compression molding. As a method for producing a resin molded article, a method including a step of injection molding a resin composition containing a polyolefin under conditions of a cylinder temperature of 180°C or higher and 260°C or lower and a residence time of 20 seconds or higher and 1800 seconds or lower is preferred. Furthermore, from the viewpoint of obtaining a resin molded article with excellent color tone, it is preferable to continuously supply an inert gas such as nitrogen during molding to replace the internal air.

[0117] <<Uses and Components of Molded Articles>> The propylene-based resin composition of the present invention can be molded into various shapes of components. The method for molding the propylene-based resin composition is not particularly limited, and known molding methods can be applied. For example, molding can be performed by any of molding methods such as extrusion molding, injection molding, vacuum molding, blow molding, injection compression molding, decorative molding, other material molding, gas-assisted injection molding, foam injection molding, low-pressure molding, ultra-thin-wall injection molding (ultra-high-speed injection molding), and in-mold composite molding (insert molding, outsert molding). Injection molding and press molding are particularly preferred.

[0118] The propylene-based resin composition of the present invention is suitable for use in applications where uniform quality is required, and where excellent properties such as flowability, productivity, and product appearance are required.

[0119] For example, the material can be suitably used in various fields such as automobile parts, home appliance parts, industrial machine parts, daily necessities, food containers, and medical parts.

[0120] Examples of the automobile parts include automobile interior and exterior components such as bumpers, pillars, and instrument panels; automobile functional components such as engine fans and fan shrouds; and exterior panel materials such as roofs, door panels, and fenders.

[0121] Examples of the home appliance parts include chassis, trays, side panels, parts for office automation equipment such as printers and copiers, parts for cameras or video equipment such as video movie cameras, digital video cameras, cameras, and digital cameras, parts for music, video, or information equipment such as navigation systems and mobile personal computers, parts for communication equipment such as mobile phones and facsimiles, parts for electrical equipment, and parts for electronic equipment.

[0122] Other examples of molded articles include architectural products such as staircase handrails and floor support members; disposable cameras; electronic and electrical parts (for example, personal computer cases, mobile phone cases, office automation equipment, audiovisual equipment, telephones, facsimiles, home appliances, toys, etc.); and vending machines.

[0123] Further examples include industrial machine parts (for example, electromagnetic device housings, medical device components, etc.), general machine parts, automobile, railway, vehicle, etc. parts (for example, outer panels, seats, etc.), ship components (for example, hulls, seats, etc.), aviation-related parts (for example, doors, seats, interior materials, etc.), spacecraft and artificial satellite components (for example, motor cases, main wings, structures, antennas, etc.).

[0124] Examples of the household goods include toys, fasteners, chains, conveyors, buckles, sporting goods, furniture, musical instruments, construction and civil engineering materials, household goods, and materials for sporting and leisure goods.

[0125] Examples of the food container include food packaging films, food packaging lids, and food container materials.

[0126] Examples of the medical parts include pressure-type cap-opening containers, blood suction tips, reagent reaction tips, reagent cartridges, caps for chemical containers, virgin seal containers, and assembly tip racks.

[0127] Examples 1 to 12, Comparative Examples 1 to 12 The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0128] The components used in the examples and comparative examples are as follows.

[0129] [Raw Material] Production of Propylene-Based Block Copolymer (A-1) (1) Preparation of Solid Titanium 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 1 hour to dissolve the phthalic anhydride.

[0130] 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 then maintained at the same temperature with stirring for 2 hours. After the 2-hour reaction was completed, the solid portion was collected by hot filtration, resuspended in 275 ml of titanium tetrachloride, and heated again at 110°C for 2 hours.

[0131] After the reaction was completed, the solid portion was again collected by hot filtration and thoroughly washed with decane and hexane at 110°C until no free titanium compounds were detected in the washings. The detection of free titanium compounds was confirmed by the following method. 10 ml of the washings for the solid titanium catalyst component was taken with a syringe and placed in a 100 ml sidearm Schlenk tube previously purged with nitrogen. The hexane solvent was then dried under a nitrogen stream and further vacuum dried for 30 minutes. 40 ml of ion-exchanged water and 10 ml of sulfuric acid were added to the mixture and stirred for 30 minutes. This aqueous solution was transferred to a 100 ml measuring flask through filter paper, and subsequently, conc. H was added as a masking agent for iron (II) ions. ３ P.O. ４ 1 ml of titanium dioxide and 3% H ２ O ２ The flask was shaken and mixed, and after 20 minutes, the absorbance at 420 nm was measured using UV, and free titanium was washed away until this absorption was no longer observed.

[0132] The solid titanium catalyst component prepared as described above was stored as a decane slurry, and a portion of this was dried for the purpose of examining the catalyst composition, which consisted of 2.3 wt % titanium, 61 wt % chlorine, 19 wt % magnesium, and 12.5 wt % DIBP.

[0133] (2) Preparation of Prepolymerization Catalyst: 100 g of the above solid titanium catalyst component, 131 mL of triethylaluminum, 37.3 ml of diethylaminotriethoxysilane, and 14.3 L of heptane were charged into a 20 L autoclave equipped with a stirrer, and 1,000 g of propylene was charged while maintaining the internal temperature at 15 to 20°C, followed by 120 minutes of stirring to carry out the reaction. After completion of the polymerization, the solid component was allowed to settle, and the supernatant was removed and washed twice with heptane. The resulting prepolymerization catalyst was resuspended in purified heptane to a solid titanium catalyst component concentration of 1.0 g / L.

[0134] (3) Main polymerization: To a 58 L jacketed circulation tubular polymerization reactor, propylene was continuously fed at 40 kg / h, hydrogen at 128 NL / h, the catalyst slurry produced in (2) at 0.46 g / h as a solid titanium catalyst component, triethylaluminum at 3.3 ml / h, and diethylaminotriethoxysilane at 1.3 ml / h, and a polypropylene homopolymer was polymerized in a liquid-filled state with no gas phase present. The temperature of the tubular polymerization reactor was 70°C, and the pressure was 3.23 MPa / G.

[0135] The resulting polypropylene homopolymer slurry was transferred to a 100 L vessel polymerization reactor equipped with a stirrer, where further polymerization was carried out. Propylene was supplied to the polymerization reactor at a rate of 15 kg / h, and hydrogen was supplied so that the hydrogen concentration in the gas phase was 1.2 mol%. Polymerization was carried out under conditions of a polymerization temperature of 70°C and a pressure of 3.03 MPa / G.

[0136] The resulting polypropylene homopolymer slurry was transferred to a 2.4 L transfer tube, where it was gasified and subjected to gas-solid separation. The polypropylene homopolymer powder was then sent to a 480 L gas-phase polymerization reactor, where ethylene / propylene block copolymerization was carried out. Propylene, ethylene, and hydrogen were continuously supplied to the gas-phase polymerization reactor so that the gas composition was ethylene / (ethylene + propylene) = 0.23 (molar ratio) and hydrogen / ethylene = 0.0065 (molar ratio). Polymerization was carried out at a polymerization temperature of 70°C and a pressure of 0.90 MPa / G.

[0137] The resulting propylene-based block copolymer (A-1) was dried in a vacuum at 80°C.

[0138] The analysis was carried out as described below.

[0139] The resulting propylene-based block copolymer (A-1) had an MFR (230° C., 2.16 kg) of 50.9 g / 10 min.

[0140] The propylene-based block copolymer (A-1) had a content of n-decane insoluble components (Dinsol) at room temperature (23° C.) of 91.0 wt %, and an intrinsic viscosity [η] of 0.9 (dl / g).

[0141] Furthermore, the content of n-decane soluble components (Dsol) at room temperature (23° C.) was 9.0 wt %, and the intrinsic viscosity [η] was 7.0 (dl / g).

[0142] Polyethylenes (B-1) to (B-5) The following polyethylenes (B-1) to (B-5) have the following MFR (190° C., 2.16 kg load) and densities, respectively.

[0143] Polyethylene (B-1): MFR 12.3 g / 10 min, density 962 kg / m ３ Polyethylene (B-2): MFR 5.1 g / 10 min, density 964 kg / m ３ Polyethylene (B-3): MFR 0.4 g / 10 min, density 957 kg / m ３Polyethylene (B-4): MFR 0.11 g / 10 min, density 958 kg / m ３ Polyethylene (B-5): MFR 0.03 g / 10 min, density 952 kg / m ３ The pellets of the propylene-based block copolymer (A-1) and the polyethylenes (B-1) to (B-5) obtained above were evaluated by the methods described below.

[0144] The viscosity (Pa·s) is the value at a temperature of 200° C. and a shear rate of 1216 (1 / sec). The results are shown in Table 1.

[0145]

[0146] Ethylene / α-olefin copolymers (C-1) to (C-3) are all thermoplastic elastomers produced using a metallocene catalyst, and those having the following MFR (230°C, 2.16 kg load) and density were used and evaluated by the methods described below. The results are shown in Table 2.

[0147] Ethylene-α-olefin copolymer (C-1) Ethylene-octene random copolymer Thermoplastic elastomer MFR 2g / 10min Density 870kg / m ３ Ethylene-α-olefin copolymer (C-2) Ethylene-butene random copolymer Thermoplastic elastomer MFR 0.7 g / 10 min Density 861 kg / m ３ Ethylene-α-olefin copolymer (C-3) Ethylene-butene random copolymer Thermoplastic elastomer MFR 0.5 g / 10 min Density 861 kg / m ３

[0148]

[0149] Inorganic filler (D-1): Talc (manufactured by Matsumura Sangyo Co., Ltd., product name 5000PJ), average particle size 4 μm was used.

[0150] Lubricant (E-1) Erucamide (manufactured by Nippon Fine Chemical Co., Ltd., product name Neutron S) was used.

[0151] [Evaluation] (Evaluation of Propylene-Based Block Copolymer) (1) Melt Mass Flow Rate (MFR) Measured in accordance with ISO 1133 under conditions of a test load of 2.16 kg and a test temperature of 230°C.

[0152] (2) Amount of n-decane soluble (insoluble) components at room temperature (23°C) Approximately 3 g (10 －４ The weight was measured to the nearest g. This weight was represented as b (g) in the formula below. ), 500 ml of decane, and a small amount of a heat stabilizer soluble in decane were added, and the mixture was heated to 150°C over 2 hours while stirring with a stirrer under a nitrogen atmosphere to dissolve the propylene-based block copolymer. The mixture was then maintained at 150°C for 2 hours and then slowly cooled to room temperature (23°C) over 8 hours. The resulting liquid containing a precipitate of the propylene-based block copolymer was filtered under reduced pressure using a 25G-4 glass filter manufactured by Iwata Glass Co., Ltd.

[0153] 100 ml of the filtrate was collected and dried under reduced pressure to obtain a part of the decane-soluble components. －４ (This weight is represented as a (g) in the formula below.) After this operation, the amount of decane-soluble components was determined by the formula below.

[0154] Content of component soluble in n-decane at room temperature (Dsol) = 100 × (500 × a) / (100 × b) Content of component insoluble in n-decane at room temperature (Dinsol) = 100 - 100 × (500 × a) / (100 × b) (3) Ethylene content of decane soluble portion at 23°C The ethylene content was measured by Fourier transform infrared spectroscopy (FT-IR).

[0155] (4) Intrinsic Viscosity [η] (dl / g) After polymer particles were dissolved in decalin, the intrinsic viscosity was measured in decalin at 135° C. according to a conventional method.

[0156] (Production of Resin Composition) Using a twin-screw extruder (Toshiba Machine Co., Ltd., "TEM-26SS", L / D = 48, equipped with a vent), the cylinder temperature was set to 200°C, and the components shown in Table 3 were mixed together and fed from the main throat of the extruder using a quantitative feeder. The resin kneaded product was extruded in the form of strands under conditions of a screw rotation speed of 150 rpm and an extrusion rate of 20 kg / h, which were then quenched in a strand bath and cut with a strand cutter to obtain a resin composition in the form of pellets.

[0157] <Viscosity> Using pellets comprising the propylene block copolymer (A-1), the polyethylenes (B-1) to (B-5), and the ethylene-α-olefin copolymers (C-1) to (C-3) obtained in [Raw Materials], viscosity was evaluated using a Capilograph manufactured by Toyo Seiki Seisaku-Sho, Ltd. (Capilograph 1D manufactured by Toyo Seiki Seisaku-Sho, Ltd.) at a melting temperature of 200°C, a capillary length of 40 mm, a capillary diameter of 1 mm, and various piston speeds.

[0158] <Melt Mass Flow Rate (MFR, 230°C, Load 2.16 kg)> Using pellets of the propylene block copolymer (A-1), polyethylenes (B-1) to (B-5), and ethylene-α-olefin copolymers (C-1) to (C-3) obtained in [Raw Materials], the melt mass flow rate (MFR, 230°C, load 2.16 kg) was measured under conditions in accordance with ISO 1133-1.

[0159] However, MFR-1 was evaluated at 230°C, and MFR-2 was evaluated at 190°C.

[0160] <Molding of Propylene-Based Resin Composition> Using an injection molding machine (EC-75NII, manufactured by Toshiba Machine Co., Ltd.), a multipurpose test piece was molded in accordance with ISO 294. The propylene-based resin composition of the present invention was molded under conditions in accordance with ISO 19069-2.

[0161] < Room temperature Charpy impact strength (kJ / m ２)> Using the multipurpose test specimen obtained in the above <Molding of propylene-based resin composition>, notching was carried out in accordance with ISO 179. The notched test specimen was used to measure the room temperature Charpy impact strength (kJ / m) under the conditions of 23°C and a hammer capacity of 4J. ２ ) was measured.

[0162] <Flexural Modulus (MPa)> Using the multipurpose test piece obtained in the above <Molding of Propylene-Based Resin Composition>, the flexural modulus (MPa) was measured in accordance with ISO 178 at a test speed of 2 mm / min.

[0163] <Appearance of molded article 1 (mirror gloss)> A mold that gives a mirror-finished surface to the molded article was used, and a square plate having a length of 130 mm, a width of 120 mm, and a thickness of 3 mm was molded at a molding temperature of 205°C and a mold temperature of 40°C. The test piece was used to measure the specular gloss using a gloss meter (UGV-6P manufactured by Suga Test Instruments Co., Ltd.) at a light source irradiation angle of 60°.

[0164] The evaluation criteria were as follows:

[0165] Glossiness of less than 16: ◯ Glossiness of 16 or more: × <Appearance of molded article 2 (surface irregularities)> Using a mold that gives a mirror-finished surface to the molded article, a square plate having a length of 350 mm, a width of 100 mm and a thickness of 2 mm was molded at a molding temperature of 205°C and a mold temperature of 40°C. The square plate was used as a test piece, and the number of irregularities on the surface of the molded piece was visually evaluated.

[0166] The evaluation criteria were as follows: 1 was good appearance, and 4 was considered to be worse appearance.

[0167] 1. 1 to 20 pieces: ◯ 2. 20 to 50 pieces: △ 3. 50 to 100 pieces: ▲ 4. 100 pieces or more: X <Surface hardness (Rockwell hardness)> A D2 square plate with a length of 60 mm, a width of 60 mm, and a thickness of 2 mm was molded at a molding temperature of 190°C and a mold temperature of 40°C to prepare a test specimen. The Rockwell hardness of the obtained test specimen was measured in accordance with ISO 2039-2.

[0168] <Evaluation of scratch resistance> The square plates prepared in the above <Appearance of molded article 1 (mirror gloss)> were used as test pieces, and the surfaces of the test pieces were scratched with a tungsten needle having a diameter of 0.75 mm under a load of 600 g, and the scratches were visually observed. The evaluation criteria were as follows:

[0169] 1. Scratches are not noticeable: 〇 2. Scratches are noticeable from some angles: △ 3. Scratches are noticeable from various angles: ×

[0170]

[0171]

[0172]

[0173] As can be seen from Table 3 (part 1 / 3), Table 3 (part 2 / 3), and Table 3 (part 3 / 3) above, by using a specific viscosity ratio and specific blending amount, the material has an excellent balance of appearance, scratch resistance, and mechanical properties of the molded product.

[0174] Furthermore, the gloss values ​​of the molded articles of Examples 2, 5, and 6, which used polyethylene (B-3), polyethylene (B-4), and polyethylene (B-5) as the polyethylene (B), and Comparative Examples 6, 7, and 8, were approximately the same. Thus, when polyethylene (B) having an MFR (230°C) of, for example, 1 or less is used, compositions with approximately the same low gloss properties can be stably produced even if the MFR (230°C) varies within that range. One reason for this is thought to be that the molded articles contain an ethylene / α-olefin copolymer (C).

Claims

1. A propylene-based resin composition comprising a propylene-based block copolymer (A), polyethylene (B), an ethylene-α-olefin copolymer (C), an inorganic filler (D), and a lubricant (E), wherein the respective amounts of (A) are 40 to 85 parts by mass, (B) are 2 to 30 parts by mass, (C) are 2 to 25 parts by mass, and (D) are 5 to 30 parts by mass (where the total of (A), (B), (C), and (D) is 100 parts by mass), and further, (E) is 0.1 to 3.0 parts by mass per 100 parts by mass of (A), (B), (C), and (D), and the ratio ηB / ηA of the viscosity ηA (Pa s) of (A) to the viscosity ηB (Pa s) of (B) is 3.3 to 4.9 (where the viscosities ηA and ηB are measured at a temperature of 200°C and a shear rate of 1216 (1 / sec)).

2. The density of polyethylene (B) is 930 to 965 kg / m ３ The propylene-based resin composition according to claim 1, wherein 3. The propylene-based resin composition according to claim 1, wherein the polyethylene (B) has a melt mass flow rate (MFR, 230°C, load 2.16 kg) of 0.08 to 1.0 g / 10 min.

4. The density of the ethylene-α-olefin copolymer (C) is 880 kg / m ３ The propylene-based resin composition according to claim 1, wherein:

5. The propylene-based resin composition according to claim 1, wherein the ethylene / α-olefin copolymer (C) has a melt mass flow rate (MFR, 230°C, load 2.16 kg) in the range of 0.1 to 5.0 g / 10 min.

6. The propylene-based resin composition according to claim 1, characterized in that the melt mass flow rate (MFR, 230°C, load 2.16 kg) of the propylene-based resin composition is 10 to 50 g / 10 min.

7. A molded article made from the propylene-based resin composition according to claim 1.

8. A method for producing the propylene-based resin composition according to claim 1, characterized by melt-kneading a propylene-based block copolymer (A), a polyethylene (B), an ethylene-α-olefin copolymer (C), an inorganic filler (D), and a lubricant (E).

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