Powder composition and injection molded article

Abstract

The present invention provides a polymer composition that exhibits excellent color expression, such as jet blackness. [Solution] A polymer composition comprising a specific propylene homopolymer (A), a styrene copolymer elastomer (C) having a content of styrene-derived structural units of 12 to 20% by mass and a melt flow rate of 0.1 g / 10 min or more and less than 10 g / 10 min as measured by a measurement method in accordance with ASTM D1238 under conditions of 230°C and a 2.16 kg load, a specific ethylene-α-olefin copolymer (D), a colorant (E) containing at least one pigment selected from the group consisting of carbon black and organic pigments, and an inorganic filler (F), wherein the content of each component is within a specific range.

Description

[Technical Field]

[0001] This disclosure relates to polymer compositions and injection-molded articles. [Background technology]

[0002] Propylene polymers have a wide range of applications as materials with excellent rigidity and heat resistance. For this reason, polymer compositions containing propylene polymers are widely used as materials for forming molded articles, such as automotive parts (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2011-116827 [Overview of the project] [Problems that the invention aims to solve]

[0004] In recent years, there has been a growing demand for materials to exhibit desired color tones, such as jet black, in order to create a sense of luxury or high quality, for example, in the interior or exterior materials of automobiles. The purpose of this disclosure is to provide a polymer composition that exhibits excellent color tone expression, such as jet black. [Means for solving the problem]

[0005] One embodiment of the polymer composition of the present disclosure includes 10 to 80% by mass of a polypropylene part (a-1) having an intrinsic viscosity [η] measured in decalin at 135°C of 5 to 13 dl / g, and 90 to 20% by mass of a polypropylene part (a-2) having an intrinsic viscosity [η] measured in decalin at 135°C of less than 5 dl / g, a propylene homopolymer (A), a styrene copolymer elastomer (C) in which the content ratio of styrene-derived structural units is 12 to 20% by mass and the melt flow rate measured under the conditions of 230°C and a load of 2.16 kg by a measuring method conforming to ASTM D1238 is 0.1 g / 10 min or more and less than 10 g / 10 min, and a copolymer of ethylene and an α-olefin having 4 carbon atoms, and the melt flow rate measured under the conditions of 230°C and a load of 2.16 kg by a measuring method conforming to ASTM D1238 is 0.1 to 10 g / 10 min and the density is 0.850 to 0.895 g / cm 3 an ethylene·α-olefin copolymer (D), a colorant (E) containing at least one pigment selected from the group consisting of carbon black and organic pigments, and an inorganic filler (F), In the above polymer composition, based on the mass of the polymer composition, the content ratio of (A) is more than 20% by mass and 97% by mass or less, the content ratio of (C) is 1% by mass or more and less than 10% by mass, the content ratio of (D) is 1% by mass or more and 35% by mass or less, the content ratio of (E) is 0.01% by mass or more and 2.0% by mass or less, and the content ratio of (F) is 0.1% by mass or more and 9.5% by mass or less.

Advantages of the Invention

[0006] One embodiment of the polymer composition of the present disclosure is a composition excellent in the expression of color tones such as jet blackness.

Mode for Carrying Out the Invention

[0007] In this specification, a numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value. In this specification, when the units of the numerical values described before and after "~" indicating a numerical range are the same, the unit of the numerical value described before "~" may be omitted.

[0008] In this specification, without particularly distinguishing between a homopolymer and a copolymer, it may be described as "polymer". That is, the term "polymer" is used in a meaning that it may be a homopolymer or a copolymer.

[0009] [Polymer composition] One embodiment of the polymer composition of the present disclosure (hereinafter also referred to as "this composition") contains a propylene homopolymer (A), a styrene copolymer elastomer (C), an ethylene·α-olefin copolymer (D), a colorant (E), and an inorganic filler (F).

[0010] [Propylene homopolymer (A)] The propylene homopolymer (A) (hereinafter also referred to as "component (A)") is composed of (a-1) 10 to 80% by mass of a polypropylene part (hereinafter also referred to as "high molecular weight PP part") having an intrinsic viscosity [η] measured in decalin at 135°C of 5 to 13 dl / g, and (a-2) 90 to 20% by mass of a polypropylene part (hereinafter also referred to as "low molecular weight PP part") having an intrinsic viscosity [η] measured in decalin at 135°C of less than 5 dl / g. and contains them.

[0011] The composition containing component (A) including such a high molecular weight PP part together with each of the components described below can form a molded body having an excellent balance between rigidity and impact resistance, and can also form a molded body having excellent color tone such as high-level blackness, for example. This composition may contain one kind of component (A) or may contain two or more kinds.

[0012] The intrinsic viscosity [η] of the high molecular weight PP portion (a-1), measured in decalin at 135°C, is 5 to 13 dl / g, preferably 5 to 12 dl / g, and more preferably 5 to 11 dl / g. The intrinsic viscosity [η] of the low molecular weight PP portion (a-2), measured in decalin at 135°C, is less than 5 dl / g, preferably 0.1 to 4 dl / g, and more preferably 0.3 to 3 dl / g.

[0013] The content ratio of the high molecular weight PP portion (a-1) to the total component (A) is 10 to 80% by mass, preferably 10 to 50% by mass, and more preferably 10 to 30% by mass. By using component (A) containing the high molecular weight PP portion (a-1) in a range above the lower limit, the elastic modulus can be improved, and the ability to produce high levels of color, such as jet blackness, can be improved. The content ratio of the low molecular weight PP portion (a-2) to the total component (A) is 90 to 20% by mass, preferably 90 to 50% by mass, and more preferably 90 to 70% by mass. By using component (A) containing the low molecular weight PP portion (a-2) in a range above the lower limit, fluidity can be improved. It is preferable that the sum of the content ratios of the high molecular weight PP portion (a-1) and the low molecular weight PP portion (a-2) relative to the entire component (A) is 100% by mass of the entire component (A).

[0014] The intrinsic viscosity [η] of component (A), as measured in decalin at 135°C, is preferably 1 to 9 dl / g, more preferably 1.5 to 8 dl / g, and even more preferably 2 to 7 dl / g.

[0015] Component (A) 13 The isotactic pentad fraction (mmmm fraction) measured by 13C-NMR is preferably 95% or higher, more preferably 97% or higher. The mmmm fraction is an indicator of the stereoregularity of component (A), and the larger this value, the higher the stereoregularity.

[0016] The mmmm fraction is 13The mmmm fraction is an isotactic chain at the pentad unit level in a polypropylene molecular chain, measured by 13C-NMR. It represents the fraction of propylene monomer units at the center of a chain consisting of five consecutive meso-bonded propylene monomer units. Specifically, the mmmm fraction is: 13 This value is determined as the mmmm peak fraction within the total absorption peaks in the methyl carbon region in a 1C-NMR spectrum.

[0017] The melt flow rate (MFR) of component (A) is preferably 0.01 to 50 g / 10 min, more preferably 0.05 to 10 g / 10 min, and even more preferably 0.1 to 5 g / 10 min. By using a polymer composition containing component (A) having such an MFR, a molded article with excellent moldability and mechanical properties can be obtained. The MFR of component (A) is measured under conditions of 230°C and a 2.16 kg load by a measurement method in accordance with ASTM D1238.

[0018] The Mw / Mn ratio of component (A), as measured by gel permeation chromatography (GPC), is preferably 6 to 20, more preferably 8 to 20. Mw is the weight-average molecular weight, and Mn is the number-average molecular weight. The Mz / Mw ratio of component (A), as measured by GPC, is preferably 2 or more, more preferably 3 or more. Mz is the z-average molecular weight. Details of the measurement conditions for the GPC method will be described later.

[0019] The fact that component (A) has an Mw / Mn ratio of 6 to 20 and an Mz / Mw ratio of 2 or more or 3 or more indicates that component (A) has a wider distribution towards higher molecular weights compared to typical propylene polymers.

[0020] Component (A) can be produced, for example, by multi-stage polymerization in two or more stages in the presence of a catalyst for producing highly stereoregular polypropylene. The catalyst for producing highly stereoregular polypropylene is formed from, for example, (i) a solid titanium catalyst component containing magnesium, titanium, halogen and electron donor, (ii) an organometallic compound catalyst component, and (iii) an electron donor component, and may be a polymerization catalyst as described in, for example, Japanese Patent Application Publication No. 2020-158652.

[0021] Component (A) can be produced by a multi-stage polymerization of two or more steps, for example, which includes the steps of: polymerizing propylene in the presence of a catalyst for producing highly stereoregular polypropylene and substantially in the absence of hydrogen to produce a high molecular weight PP portion (a-1) in a predetermined ratio with respect to the entire component (A); and polymerizing propylene in the presence of a catalyst for producing highly stereoregular polypropylene to produce a low molecular weight PP portion (a-2) in a predetermined ratio with respect to the entire component (A). The method for adjusting the molecular weight and intrinsic viscosity [η] is not particularly limited, but a method using hydrogen as a molecular weight adjusting agent is preferred.

[0022] The preferred order of carrying out the above steps is to first produce a high molecular weight PP portion (a-1) in substantially the absence of hydrogen in the first stage, and then produce a low molecular weight PP portion (a-2) in the second stage and beyond. The intrinsic viscosity [η] of the PP portion from the second stage onward can be calculated, for example, from the intrinsic viscosity [η] of the PP portion from the first stage and the ratio of the amounts of the PP portion from the first stage and the PP portion from the second stage onward. The order in which the above steps are performed can also be changed. For example, the low molecular weight PP portion (a-2) may be produced in the first step, and then the high molecular weight PP portion (a-1) may be produced in the second step and beyond. In this case, it is preferable to remove as much as possible of the molecular weight adjusting agent, such as hydrogen, contained in the reaction product of the first step before the start of polymerization in the second step and beyond. Therefore, the polymerization apparatus may become more complex, and the intrinsic viscosity [η] in the second step and beyond may not increase easily.

[0023] Polymerization at each stage can be carried out continuously, in batches, or semi-continuously, but continuous polymerization is preferred. Polymerization can be carried out by known methods such as gas-phase polymerization, or liquid-phase polymerization methods such as solution polymerization, slurry polymerization, or bulk polymerization. It is preferable that the polymerization from the second stage onward is carried out continuously following the polymerization of the preceding stage. When polymerization is carried out in batches, multi-stage polymerization can also be performed using a single polymerizer.

[0024] In this specification, propylene homopolymer (A) and propylene polymer (B) described later may be polymers obtained using only fossil fuel-derived olefins such as fossil fuel-derived propylene as raw materials, polymers obtained using only biomass-derived olefins such as biomass-derived propylene as raw materials, polymers obtained using only chemically recycled olefins such as chemically recycled propylene as raw materials, or polymers obtained using a mixture of two or more selected from the group consisting of fossil fuel-derived olefins, biomass-derived olefins and chemically recycled olefins as raw materials, or a mixture of two or more of these polymers.

[0025] The propylene homopolymer (A) may contain constituent units derived from biomass-derived propylene. The propylene constituting the polymer (A) may consist solely of biomass-derived propylene, or it may contain both biomass-derived propylene and fossil fuel-derived propylene. Biomass-derived propylene is propylene obtained from any renewable natural raw materials and their residues, including fungi, yeasts, algae, and bacteria, which are of plant or animal origin, and contains carbon as 14 1 × 10¹¹ C isotopes -12 ~1 × 10 -14It contains at a certain percentage, and the biomass carbon concentration (pMC) measured in accordance with ASTM D6866 is about 100 (pMC). Propylene derived from biomass is obtained by a conventionally known method. It is preferable that the propylene homopolymer (A) contains a structural unit derived from biomass-derived propylene from the viewpoint of reducing environmental impact (mainly reducing greenhouse gas emissions). If the polymer production conditions such as the polymerization catalyst, polymerization process, and polymerization temperature are the same, the propylene homopolymer composed of raw material propylene containing biomass-derived propylene is 14 C isotope is 1×10 -12 ~1×10 -14 For the molecular structure other than containing at a certain percentage, it is equivalent to the propylene homopolymer composed of fossil fuel-derived propylene. Therefore, the performance is also considered to be equivalent.

[0026] The propylene homopolymer (A) may contain a structural unit derived from propylene derived from chemical recycling. The propylene constituting the polymer (A) may be only propylene derived from chemical recycling, or may contain propylene derived from chemical recycling and non-chemically recycled fossil fuel-derived propylene and / or biomass-derived propylene. Propylene derived from chemical recycling is obtained by a conventionally known method. It is preferable that the propylene homopolymer (A) contains a structural unit derived from propylene derived from chemical recycling from the viewpoint of reducing environmental impact (mainly reducing waste). If the polymer production conditions such as the polymerization catalyst, polymerization process, and polymerization temperature are the same, the propylene homopolymer composed of raw material propylene containing propylene derived from chemical recycling is equivalent to the propylene homopolymer composed of non-chemically recycled fossil fuel-derived propylene. Therefore, the performance is also considered to be equivalent.

[0027] <Propylene polymer (B)> This composition may further contain a propylene polymer other than the propylene homopolymer (A) (hereinafter also referred to as "propylene polymer (B)" or "component (B)"). The propylene polymer (B) does not correspond to the propylene homopolymer (A). This composition may contain one type of component (B), or it may contain two or more types.

[0028] Component (B) is a polymer mainly having propylene-derived structural units, and is not a propylene homopolymer (A). The content of propylene-derived structural units in component (B) is preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more, out of the total amount of polymerizable monomer-derived structural units. The content of the above structural units is, 13 It is measured by 13C-NMR.

[0029] Component (B) may further have constituent units derived from α-olefins having 2 or 4 to 12 carbon atoms. Examples of the α-olefins include ethylene, 1-butene, 1-octene, isobutylene, and 4-methyl-1-pentene.

[0030] Examples of component (B) include propylene homopolymers, propylene block copolymers, and propylene random copolymers. Among these, propylene homopolymers are preferred as component (B). The isotactic pentad fraction (mmmm fraction) of the propylene homopolymer is preferably 96% or higher. The mmmm fraction is measured by the method described above.

[0031] The MFR of component (B) is preferably 1 to 500 g / 10 min, more preferably 3 to 400 g / 10 min, and even more preferably 5 to 300 g / 10 min, and may be greater than 5 g / 10 min, or 6 g / 10 min or more. From the viewpoint of moldability, it is preferable that the MFR is above the lower limit. From the viewpoint of impact resistance, it is preferable that the MFR is below the upper limit. The MFR of component (B) is measured under conditions of 230°C and a load of 2.16 kg by a measurement method in accordance with ASTM D1238.

[0032] The propylene polymer (B) may contain constituent units derived from biomass-derived propylene. The propylene constituting the polymer (B) may consist solely of biomass-derived propylene, or it may contain both biomass-derived propylene and fossil fuel-derived propylene. It is preferable for the propylene polymer (B) to contain constituent units derived from biomass-derived propylene from the viewpoint of reducing environmental impact (mainly greenhouse gas reduction).

[0033] The propylene polymer (B) may contain constituent units derived from chemically recycled propylene. The propylene constituting the polymer (B) may consist solely of chemically recycled propylene, or it may contain chemically recycled propylene and non-chemically recycled propylene derived from fossil fuels and / or biomass. It is preferable for the propylene polymer (B) to contain constituent units derived from chemically recycled propylene from the viewpoint of reducing environmental impact (mainly waste reduction).

[0034] <Styrene copolymer elastomer (C)> Styrene copolymer elastomer (C) (hereinafter also referred to as "elastomer (C)") is a component for improving the color development, such as jet blackness, and impact resistance of molded articles obtained from this composition. This composition may contain one type of elastomer (C), or it may contain two or more types.

[0035] The MFR of elastomer (C) is preferably 0.1 g / 10 min or more and less than 10 g / 10 min, more preferably 0.5 to 9 g / 10 min, even more preferably 1 to 8 g / 10 min, and particularly preferably 2 to 6 g / 10 min. The MFR is measured under conditions of 230°C and a 2.16 kg load by a measurement method in accordance with ASTM D1238.

[0036] The content of styrene-derived structural units in elastomer (C) is preferably 12 to 20% by mass, more preferably 15 to 20% by mass, based on the mass of elastomer (C), from the viewpoint of achieving a better balance between the rigidity and impact resistance of the molded article formed from this composition. The content of each structural unit, such as styrene-derived structural units, in elastomer (C) is measured by NMR.

[0037] The glass transition temperature (Tg) of the elastomer (C) is preferably 0°C or lower, more preferably -90 to -10°C, and even more preferably -80 to -20°C. The glass transition temperature (Tg) is defined as the peak temperature of tanδ obtained by dynamic viscoelasticity measurement (measurement mode: torsion mode, heating rate: 5°C / min, measurement frequency: 1Hz).

[0038] As the elastomer (C), for example, a copolymer of styrene and a conjugated diene compound and / or its hydrogenated product is preferred, a block copolymer of styrene and a conjugated diene compound and / or its hydrogenated product is more preferred, and a hydrogenated block copolymer of styrene and a conjugated diene compound is even more preferred.

[0039] As for elastomers (C), polymer blocks (C) mainly containing styrene-derived structural units. A ) and polymer blocks (C) mainly consisting of structural units derived from conjugated diene compounds B At least one selected from the group consisting of block copolymers having ) and their hydrogenated products is preferred.

[0040] In the above block copolymer or its hydrogenated product, for example, the polymer block (C) is a hard segment. A ) is a polymer block (C B ) or exists as a crosslinking point of the hydrogenated block, forming a physical crosslink (domain). Polymer block (C A ) Polymer blocks (C B ) or its hydrogenated block is, for example, a soft segment having rubber elasticity.

[0041] A "polymer block mainly containing styrene (or conjugated diene compound)-derived structural units" means a polymer block containing styrene (or conjugated diene compound)-derived structural units in an amount exceeding 50% by mass. The content of styrene (or conjugated diene compound)-derived structural units in the polymer block may be, for example, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more.

[0042] Examples of conjugated diene compounds include butadiene, isoprene, pentadiene, and 2,3-dimethylbutadiene, as well as combinations of two or more selected from these. Among these, butadiene, isoprene, or a combination of butadiene and isoprene is preferred.

[0043] Add block (C B If the polymer block (C) is formed from butadiene and isoprene, B ) may be a random copolymer block of butadiene and isoprene, a block copolymer block, or a tapered copolymer block. Add block (C B If the polymer block (C) is formed from butadiene and isoprene, B The content of isoprene-derived constituent units in the mixture is preferably 40 mol% or more.

[0044] Add block (C A ) and polymer block (C B The block copolymer having ) is, for example, A(BA) n1 , or (AB) n1 Block copolymer represented by (AB) (wherein n1 is an integer of 1 or more, preferably an integer from 1 to 3) n2 Examples of block copolymers are those represented by X (wherein n2 is an integer between 3 and 6, and X is a residue of a coupling agent such as silicon tetrachloride, tin tetrachloride, and a polyepoxy compound). The above A is a polymer block (C A) represents the polymer block (C). The above B represents the polymer block (C B ) represents. Among these, A(BA) n1 The block copolymer represented by is preferred, and the block copolymer represented by ABA is more preferred.

[0045] Examples of the block copolymers and their hydrogenated products include styrene-butadiene-styrene block copolymer (SBS) and its hydrogenated product (styrene-ethylene / butylene-styrene block copolymer (SEBS)), styrene-butadiene block copolymer (SB) and its hydrogenated product (styrene-ethylene / butylene block copolymer (SEB)), styrene-isoprene-styrene block copolymer (SIS) and its hydrogenated product (styrene-ethylene / propylene-styrene block copolymer (SEPS)), and styrene-isoprene block copolymer (SI) and its hydrogenated product (styrene-ethylene / propylene block copolymer (SEP)). Among these, at least one selected from the group consisting of SBS, SEBS, SB, and SEB is preferred from the viewpoint of improving the expression of high levels of color tone such as jet blackness, and SEBS is more preferred.

[0046] Polymer block (C) in the above block copolymer A The content of ) is preferably 5 to 30% by mass, more preferably 10 to 25% by mass, and even more preferably 15 to 20% by mass. Polymer block (C A The content ratio of ) is determined by the polymer block (C) obtained by the above block copolymer oxidatively decomposing with tert-butyl hydroperoxide using osmium tetroxide as a catalyst (method described in IM Kolthoff, et al., J. Polym. Sci. 1, 429 (1946)). A It is defined using the mass of ) as follows: Add block (C A ) content ratio (mass%) = [(polymer block (C) in block copolymer before hydrogenation] A (Mass of ) / (Mass of block copolymer before hydrogenation) × 100

[0047] In the above hydrogenated product, polymer block (C B Some or all of the carbon-carbon double bonds in the material are hydrogenated. The hydrogenation rate is preferably 60 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and particularly preferably 98 mol% or more, from the viewpoint of the heat resistance and weather resistance of the molded article. The hydrogenation rate is measured by NMR.

[0048] The above block copolymer can be produced by various methods. Examples of methods for producing the above block copolymer include: (1) a method in which an alkyllithium compound such as n-butyllithium is used as a polymerization initiator and styrene, and then a conjugated diene compound is polymerized stepwise; (2) a method in which styrene, and then a conjugated diene compound is polymerized and coupled with a coupling agent; (3) a method in which an alkyllithium compound is used as a polymerization initiator and styrene, and then a conjugated diene compound is polymerized stepwise; and (4) a combination of two or more methods selected from (1) to (3) above.

[0049] The block copolymer described above can be hydrogenated, for example, using a hydrogenation catalyst. Examples of hydrogenation catalysts include (1) supported heterogeneous hydrogenation catalysts in which metals such as Ni, Pt, Pd, and Ru are supported on carriers such as carbon, silica, alumina, and diatomaceous earth; (2) so-called Ziegler-type hydrogenation catalysts using organic acid salts of Ni, Co, Fe, or Cr, or transition metal salts such as acetylacetone salts, and reducing agents such as organoaluminum; and (3) homogeneous hydrogenation catalysts such as so-called organometallic complexes such as organometallic compounds of Ti, Ru, Rh, or Zr.

[0050] <Ethylene-α-olefin copolymer (D)> This composition contains an ethylene-α-olefin copolymer (D) (hereinafter also referred to as "polymer (D)"), which is a copolymer of ethylene and an α-olefin having 4 carbon atoms. Copolymer (D) is preferably a random copolymer. This composition, containing a colorant (E) along with a propylene homopolymer (A), an elastomer (C), and a copolymer (D), exhibits particularly excellent color development, such as jet blackness. Furthermore, copolymer (D) can enhance the impact resistance of the molded article. This composition may contain one copolymer (D) or two or more copolymers (D).

[0051] An example of an α-olefin with four carbon atoms is 1-butene. The content of ethylene-derived structural units in copolymer (D) is preferably 70 to 95 mol%, more preferably 75 to 90 mol%, out of a total of 100 mol% of ethylene-derived structural units and C4-α-olefin-derived structural units. The content of the above structural units is 13 It is measured by 13C-NMR.

[0052] The MFR of copolymer (D) is preferably 0.1 to 10 g / 10 min, more preferably 0.5 to 10 g / 10 min. Copolymer (D) having such an MFR contributes to improving the impact resistance of the molded article. The MFR of copolymer (D) is measured under conditions of 230°C and a 2.16 kg load by a measurement method in accordance with ASTM D1238.

[0053] The intrinsic viscosity [η] of copolymer (D), as measured in decalin at 135°C, is preferably 0.1 to 5.0 dl / g, more preferably 0.5 to 3.0 dl / g. Copolymer (D) having such an intrinsic viscosity [η] contributes to improving the impact resistance of molded articles.

[0054] The density of copolymer (D) is preferably 0.850 to 0.895 g / cm³. 3 , more preferably 0.855~0.875 g / cm³ 3 This is the case. Copolymer (D) having such density contributes to improving the impact resistance of molded articles. The density is measured by density gradient tube method using a sample obtained by heat-treating a strand of copolymer (D) obtained during MFR measurement at 120°C for 1 hour and then slowly cooling it to room temperature (23°C) over 1 hour.

[0055] Copolymer (D) can be produced by conventionally known methods. The MFR (Method Factor Retention) can be adjusted, for example, when copolymerizing ethylene and a carbon-4 α-olefin to produce copolymer (D), by adjusting the ratio of hydrogen gas feed as a chain transfer agent to the feed amounts of ethylene and carbon-4 α-olefin. In other words, increasing this ratio can increase the MFR, and decreasing this ratio can decrease the MFR.

[0056] The density can be adjusted, for example, by adjusting the ratio of the α-olefin feed amount to the ethylene feed amount when copolymerizing ethylene and a carbon-4 α-olefin to produce copolymer (D). In other words, increasing this ratio can lower the density, and decreasing this ratio can increase the density.

[0057] <Coloring agent (E)> This composition contains a colorant (E) comprising at least one pigment selected from the group consisting of carbon black and organic pigments. Because this composition contains a colorant (E) together with a propylene homopolymer (A), an elastomer (C), and a copolymer (D), it can exhibit a desired color tone. For example, by including carbon black and / or a black organic pigment as the colorant (E), this composition can exhibit a high level of jet blackness. Therefore, by using this composition, molded articles exhibiting a desired color tone (e.g., a color tone equivalent to or better than that of a painted product) can be manufactured without painting. This composition may contain one coloring agent (E), or it may contain two or more coloring agents.

[0058] Examples of carbon black include furnace black, lamp black, acetylene black, and channel black. One type of carbon black may be used, or two or more types may be used. The average primary particle size of carbon black is preferably 5 to 500 nm, more preferably 8 to 300 nm, and even more preferably 10 to 100 nm. The average primary particle size is measured by a measurement method in accordance with ASTM D3849-14.

[0059] Examples of organic pigments include water-soluble azo pigments, insoluble azo pigments, polyazo pigments, anthraquinone pigments, phthalocyanine pigments, quinacridone pigments, perinone-perylene pigments, azomethine pigments, isoindolinone pigments, isoindoline pigments, and pyrrolopyrrole pigments. One organic pigment may be used, or two or more may be used.

[0060] For example, the coloring agent (E) is: Carbon black, Organic pigments, and Combination of carbon black and organic pigments These are some examples.

[0061] The carbon black and organic pigments are not particularly limited as long as they are pigments that can be used for resin molded products, and can be appropriately selected from pigments known for resin molded products, commonly used pigments, or commercially available pigments.

[0062] <Inorganic filler (F)> This composition contains an inorganic filler (F) from the viewpoint of increasing the rigidity of the molded article. In this specification, the inorganic filler (F) formally excludes carbon black, which is one of the colorants (E) described above. However, this does not prevent the carbon black from functioning as an inorganic filler. This composition may contain one or more inorganic fillers (F).

[0063] As the inorganic filler (F), known inorganic fillers can be used. Examples of inorganic fillers (F) include talc, mica, calcium carbonate, magnesium carbonate, magnesium oxide, barium sulfate, titanium oxide, iron oxide, gypsum, metal powders (e.g., zinc, copper, iron, aluminum), and fibers (e.g., glass fibers). Among these, at least one selected from the group consisting of talc, mica, calcium carbonate, and glass fibers is preferred, with talc being particularly preferred.

[0064] The median diameter (D50) of talc is preferably 1 to 15 μm, more preferably 1 to 6 μm. D50 is obtained by reading the particle size value at 50% cumulative amount from a volume-based cumulative particle size distribution curve obtained in accordance with JIS R1629:1997 (laser diffraction and scattering method).

[0065] <Additives> This composition may further contain additives other than those listed above. Examples of additives include phosphorus-based or phenol-based antioxidants, benzotriazole-based weather stabilizers, dispersants such as calcium stearate, nucleating agents, lubricants, antistatic agents, heat stabilizers, and softeners.

[0066] Organic crystal nucleating agents are preferred as nucleating agents. Examples of organic crystal nucleating agents include organic acids such as succinic acid, adipic acid, and benzoic acid, as well as their metal salts; and metal organophosphates. Examples of metal organophosphates include sodium-2,2'-methylenebis(4,6-di-t-butylphenyl)phosphate, sodium-bis(4-t-phenyl)phosphate, aluminum dihydroxy-2,2'-methylene-bis(4,6-di-t-butylphenyl)phosphate, and aluminum hydroxy-bis[2,2'-methylene-bis(4,6-di-t-butylphenyl)phosphate].

[0067] Examples of lubricants include fatty acid soaps, metal soaps, paraffin waxes, hydrocarbon oils, aliphatic alcohols, low molecular weight polyethylene, fatty acid amides, and fatty acid esters. Among these, fatty acid amides are preferred from the viewpoint of minimizing the reduction in impact resistance and providing a large lubricating effect. Examples of fatty acids include erucic acid, oleic acid, and stearic acid. Examples of fatty acid amides include erucic acid amide, oleic acid amide, and stearic acid amide.

[0068] This composition may contain one or more additives. When using two or more additives, the mixing order of the additives is arbitrary; they may be mixed simultaneously, or a multi-stage mixing method may be employed in which some components are mixed before others.

[0069] <Percentage of each component> The preferred content ratios of each component in this composition are described below. The content ratios of each component are based on the mass of this composition, i.e., they represent the content ratio in 100% by mass of this composition. The above composition containing each component in these content ratios exhibits particularly excellent color development, such as jet blackness. The content of propylene homopolymer (A) in this composition is preferably more than 20% by mass and 97% by mass or less, more preferably 21 to 96% by mass, even more preferably 50 to 93% by mass, and particularly preferably 70 to 92% by mass. The content of component (A) may be, for example, 30% by mass or more, or 40% by mass or more. When the content of component (A) exceeds or is above the lower limit, the resulting molded article has excellent rigidity.

[0070] The total content of the propylene homopolymer (A), propylene polymer (B), styrene copolymer elastomer (C), ethylene-α-olefin copolymer (D), colorant (E), and inorganic filler (F) in this composition is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 97% by mass or more.

[0071] The content of component (B) in this composition is preferably 0 to 76% by mass, more preferably 0 to 60% by mass, even more preferably 0 to 42% by mass, and particularly preferably 0 to 22% by mass, from the viewpoint of balancing rigidity and impact resistance.

[0072] The elastomer (C) content in this composition is preferably 1% by mass or more and less than 10% by mass, more preferably 1 to 9.4% by mass, even more preferably 5 to 9.4% by mass, and particularly preferably 6 to 9.3% by mass. When the elastomer (C) content is above the lower limit, the resulting molded article exhibits excellent color tone, such as jet blackness, and impact resistance. When the elastomer (C) content is below or equal to the upper limit, the resulting molded article exhibits excellent rigidity.

[0073] The content of copolymer (D) in this composition is preferably 1 to 35% by mass, more preferably 1 to 20% by mass, even more preferably 1 to 10% by mass, and particularly preferably 1 to 9% by mass. When the content of elastomer (C) is above the lower limit and the content of copolymer (D) is above the lower limit, this composition exhibits particularly excellent color development, such as jet blackness. When the content of copolymer (D) is below the upper limit, the resulting molded article exhibits excellent rigidity.

[0074] The content of the colorant (E) in this composition is preferably 0.01 to 2.0% by mass, more preferably 0.05 to 2.0% by mass, even more preferably 0.1 to 2.0% by mass, and particularly preferably 0.5 to 2.0% by mass. When the content of the colorant (E) is above the lower limit, the resulting molded article can exhibit a good color tone. When the content of the colorant (E) is below the upper limit, a decrease in mechanical properties can be suppressed.

[0075] The content of the inorganic filler (F) in this composition is preferably 0.1 to 9.5% by mass, more preferably 0.1 to 9.4% by mass, even more preferably 0.2 to 7% by mass, and particularly preferably 0.5 to 6% by mass. When the content of the inorganic filler (F) is below the above upper limit, the resulting molded article has excellent color tone, for example, jet blackness.

[0076] The antioxidant content in this composition is preferably 0 to 1.5% by mass, more preferably 0 to 1% by mass, and if an antioxidant is added, it is preferably 0.1 to 1.5% by mass, more preferably 0.1 to 1% by mass. The proportion of weather stabilizer in this composition is preferably 0 to 1.5% by mass, more preferably 0 to 1% by mass, and if a weather stabilizer is added, it is preferably 0.1 to 1.5% by mass, more preferably 0.1 to 1% by mass. The dispersant content in this composition is preferably 0 to 2.0% by mass, more preferably 0 to 1.5% by mass, and if a dispersant is added, it is preferably 0.1 to 2.0% by mass, more preferably 0.1 to 1.5% by mass. The content of the nucleating agent in this composition is preferably 0 to 1.5% by mass, more preferably 0 to 1% by mass, and if a nucleating agent is added, it is preferably 0.1 to 1.5% by mass, more preferably 0.1 to 1% by mass. The lubricant content in this composition is preferably 0 to 1.5% by mass, more preferably 0 to 1% by mass, and when a lubricant is added, it is preferably 0.1 to 1.5% by mass, more preferably 0.1 to 1% by mass, even more preferably 0.2 to 1% by mass, and particularly preferably 0.3 to 1% by mass.

[0077] The total content of additives in this composition is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, and even more preferably 0 to 3% by mass.

[0078] <Physical properties of polymer compositions> The MFR of this composition is preferably 0.01 to 50 g / 10 min, more preferably 0.1 to 30 g / 10 min, and even more preferably 1 to 15 g / 10 min. The MFR of this composition is measured under conditions of 230°C and a 2.16 kg load by a measurement method in accordance with ASTM D1238.

[0079] The flexural modulus of this composition at 23°C is preferably 1750 MPa or higher, more preferably 1780 to 3000 MPa, and even more preferably 1800 to 2900 MPa. Such polymer compositions can form molded articles with excellent rigidity. The flexural modulus was measured according to the measurement method in accordance with ISO 178, and the details of the measurement conditions are described in the Examples section. The Charpy impact strength of this composition at -30°C is preferably 1.5 kJ / m². 2 More preferably, 1.7 to 10.0 kJ / m 2 More preferably 1.9 to 8.0 kJ / m 2 Such polymer compositions can form molded articles with excellent impact resistance. Charpy impact strength was measured according to the measurement method compliant with ISO 179-1, and details of the measurement conditions are described in the Examples section.

[0080] The brightness L of the central portion of an injection-molded body measuring 350 mm × 100 mm × 2 mm in thickness, obtained by injection molding this composition under the conditions described in the Examples section. * In one embodiment, this is preferably 7.5 or less, more preferably 2.0 to 7.0, even more preferably 2.0 to 6.0, even more preferably 2.5 to 5.0, and particularly preferably 3.0 to 4.5.

[0081] <Method for producing polymer compositions> This composition can be produced, for example, by mixing a propylene homopolymer (A), a styrene copolymer elastomer (C), an ethylene-α-olefin copolymer (D), a colorant (E), an inorganic filler (F), and optionally at least one selected from the group consisting of a propylene polymer (B) and additives.

[0082] This composition can be produced by kneading each of the above-mentioned components simultaneously or sequentially, for example, in a kneader. Examples of kneaders include twin-screw extruders, single-screw extruders, kneaders, Banbury mixers, and Henschel mixers.

[0083] Specifically, this composition can be produced by blending the above-mentioned components in predetermined amounts, mixing them using a Banbury mixer or Henschel mixer, and then melt-kneading them using a twin-screw extruder or single-screw extruder. The melt-kneading conditions are not particularly limited, as long as the molten resin does not deteriorate due to shear during kneading, heating temperature, or heat generation due to shear. From the viewpoint of suppressing the deterioration of the molten resin, it is effective to set the heating temperature appropriately or to add antioxidants or heat stabilizers.

[0084] [Molded body] This composition can be molded by conventionally known molding methods for resin compositions, thereby producing a molded article. Examples of molding methods include injection molding, extrusion molding, hollow molding, film molding, sheet molding, foam molding, stretch molding, vacuum molding, and press molding, with injection molding being preferred. Therefore, an injection-molded article formed from this composition is preferred as the molded article.

[0085] The above-mentioned molded articles can be used, for example, as automotive parts, home appliance parts, industrial parts, household goods, food containers, or medical containers. Among these, automotive parts such as automotive interior or exterior materials are preferred. Examples of automotive interior or exterior materials include door trims, side moldings, fenders, overfenders, side sill garnishes, bumper skirts, spoilers, mudguards, inner panels, pillars, instrument panels, back doors, back panels, and bumpers.

[0086] In recent years, there has been a demand for unpainted molded products from the perspective of reducing volatile organic compounds (VOCs) and costs. Unpainted molded products are required to have the same physical properties as painted molded products (e.g., high rigidity, high impact resistance), and in addition, high color development when colorants are added is sometimes required for unpainted molded products. As described above, by combining the above components with a coloring agent (E), this composition can exhibit desired colors such as jet black at a high level. Furthermore, this composition can form molded articles with excellent rigidity and impact resistance. In addition, if the molded article is unpainted, it also has excellent recyclability.

[0087] The above-mentioned molded body may be painted.

[0088] [Example of an embodiment] This disclosure relates, for example, to the following [1] to [5]. [1] A polymer composition comprising: a propylene homopolymer (A) comprising (a-1) 10 to 80% by mass of a polypropylene portion having an intrinsic viscosity [η] of 5 to 13 dl / g as measured in decalin at 135°C, and (a-2) 90 to 20% by mass of a polypropylene portion having an intrinsic viscosity [η] of less than 5 dl / g as measured in decalin at 135°C; a styrene copolymer elastomer (C) having a styrene-derived constituent unit content of 12 to 20% by mass and a melt flow rate of 0.1 g / 10 min or more and less than 10 g / 10 min as measured under conditions of 230°C and a 2.16 kg load according to the measurement method in accordance with ASTM D1238; and a copolymer of ethylene and a carbon-4 α-olefin, ASTM According to the measurement method compliant with D1238, the melt flow rate measured under conditions of 230°C and a 2.16 kg load was 0.1 to 10 g / 10 min, and the density was 0.850 to 0.895 g / cm³. 3 It contains an ethylene-α-olefin copolymer (D), a colorant (E) containing at least one pigment selected from the group consisting of carbon black and organic pigments, and an inorganic filler (F). The polymer composition wherein, based on the mass of the polymer composition, the content of (A) is greater than 20% by mass and 97% by mass or less, the content of (C) is 1% by mass or more and less than 10% by mass, the content of (D) is 1% by mass or more and 35% by mass or less, the content of (E) is 0.01% by mass or more and 2.0% by mass or less, and the content of (F) is 0.1% by mass or more and 9.5% by mass or less. [2] The polymer composition according to [1], wherein the polymer composition further contains a propylene polymer (B) other than the propylene homopolymer (A), and the content ratio of the propylene polymer (B) in the polymer composition is 76% by mass or less, based on the mass of the polymer composition. [3] The polymer composition according to [1] or [2], wherein the styrene copolymer elastomer (C) is a hydrogenated block copolymer of styrene and a conjugated diene compound. [4] An injection-molded article formed from any of the polymer compositions described in [1] to [3] above. [5] An injection-molded body as described in [4] above, which is an automotive part. [Examples]

[0089] The present composition will be described in more detail below based on the examples, but the present composition is not limited in any way to these examples. The methods for measuring the physical properties of the raw materials used in the examples and comparative examples are as described above, except as described below.

[0090] [Measurement conditions for the GPC method] The weight-average molecular weight (Mw), number-average molecular weight (Mn), and z-average molecular weight (Mz) of the target polymer were determined by gel permeation chromatography (GPC). Specifically, the above average molecular weights were calculated from the molecular weight distribution curve obtained using a Waters Alliance GPC 2000 gel permeation chromatograph (high-temperature size exclusion chromatograph), and the operating conditions were as follows. 《Equipment and Conditions Used》 Measurement device: Gel permeation chromatograph Alliance GPC 2000 (Waters Corporation) Analysis software: Chromatography data system Empower (Waters Corporation) Column: TSKgel GMH6-HT×2 + TSKgel GMH6-HT×2 (Inner diameter 7.5mm x length 30cm, Tosoh Corporation) Mobile phase: o-dichlorobenzene (Wako Pure Chemical Industries, Ltd., special grade reagent) Detector: Differential refractometer (built into the device) Column temperature: 140℃ Flow rate: 1.0mL / min Injection volume: 400μL Sampling time interval: 1 second Sample concentration: 0.15% (w / v) Molecular weight calibration: Monodisperse polystyrene (Tosoh Corporation) Molecular weight from 495 to 20.6 million

[0091] [Measurement conditions for intrinsic viscosity [η]] The intrinsic viscosity [η] of the target polymer was measured by a conventional method in decalin at 135°C. Specifically, approximately 20 mg of the sample was dissolved in 15 ml of decalin, and the specific viscosity [η] was measured in an oil bath at 135°C. sp The specific viscosity η was measured. After diluting this decalin solution by adding 5 ml of decalin solvent, the specific viscosity η was measured in the same manner. sp The following was measured. This dilution procedure was repeated two more times, and when the concentration (C) was extrapolated to 0, the following equation was obtained: sp The value of / C was defined as the intrinsic viscosity [η]. Intrinsic viscosity [η]=lim(η sp / C) (C→0)

[0092] [Manufacturing Example 1] Propylene Homopolymer (A-1) (Preparation of solid catalyst components) A 500 ml round-bottom flask, thoroughly purged with nitrogen gas and equipped with a stirrer, was charged with 10 g of diethoxymagnesium and 500 ml of toluene to form a suspension. 500 ml of room temperature titanium tetrachloride was added to this suspension, and the temperature was raised to 50°C while stirring. Then, 52 ml of di-iso-octyl phthalate was added, and the temperature was further raised to 100°C. 15 ml of diethyl phthalate was added, and the temperature in the system was raised to 115°C. 40 ml of dimethylpolysiloxane with a viscosity of 100 cSt at room temperature was added, and the mixture was reacted for 2 hours. After the reaction was complete, the supernatant was removed and treated with 800 ml of toluene and 200 ml of titanium tetrachloride at 100°C for 15 minutes. The mixture was then washed three times with 1000 ml of toluene at 100°C. Subsequently, 8 g of sodium stearate, 800 ml of toluene, and 200 ml of titanium tetrachloride were added, and the mixture was treated with stirring at 100°C for 2 hours. After that, it was washed eight times with 1000 ml of n-heptane at 40°C to obtain a solid catalyst component. The Ti content in the solid catalyst component was measured to be 2.5% by mass.

[0093] (Preparation of prepolymerization catalyst) 250 g of the above solid catalyst component, 32.1 g of triethylaluminum, and 125 liters of heptane were placed in a 200 liter autoclave, maintained at an internal temperature of 10°C, 180 g of propylene was added, and after stirring for 30 minutes, 18 g of titanium tetrachloride was added to obtain a prepolymerization catalyst.

[0094] (polymerization) In a polymerizer (1) with a capacity of 500 liters, heptane was continuously supplied at a rate of 87 liters / hour, a prepolymerization catalyst at 9.6 g / hour, triethylaluminum at 18.2 g / hour, and dicyclopentyl dimethoxysilane at 37.2 g / hour. Propylene was then charged into the polymerizer (1) at a temperature of 60°C under conditions where the internal pressure of the polymerizer (1) was maintained at 0.69 MPa (first stage polymerization). The slurry from the polymerizer (1) was sampled, and the intrinsic viscosity [η] of the polypropylene was measured to be 9.1 dl / g.

[0095] The obtained slurry was continuously fed into a polymerizer (2) with a capacity of 500 liters, and further polymerization was carried out. Heptane was charged into polymerizer (2) at a rate of 32 liters / hour, and propylene and hydrogen were continuously supplied to maintain the internal pressure of polymerizer (2) at 70°C, 0.69 MPa, and the hydrogen concentration in the gas phase at 10% by volume (second stage polymerization).

[0096] After removing unreacted monomers from the slurry exiting the polymerizer (2), the heptane was centrifuged using a conventional method, and then dried at 80°C and 9.3 MPa for 10 hours to obtain powdered crystalline propylene homopolymer (A-1). Crystalline propylene homopolymer (A-1) was obtained at a rate of 80 kg / hour.

[0097] The crystalline propylene homopolymer (A-1) had an MFR (230°C, 2.16 kg load) of 3.1 g / 10 min, a Mw / Mn ratio of 15, a Mz / Mw ratio of 5, and an intrinsic viscosity [η] of 2.2 dl / g. Calculated from the mass balance, the polypropylene produced in the first polymerization stage of the final crystalline propylene homopolymer (A-1) corresponded to the high molecular weight PP portion, with a proportion of 20% by mass. The polypropylene produced in the second polymerization stage corresponded to the low molecular weight PP portion, with a proportion of 80% by mass and an intrinsic viscosity [η] of 0.5 dl / g.

[0098] The components used in the following examples and comparative examples are listed below. <Propylene polymer (B)> B-1: Propylene homopolymer MFR=9g / 10min B-2: Propylene homopolymer MFR = 200g / 10 min B-3: Propylene homopolymer MFR=30g / 10min <Styrene copolymer elastomer (C)> C-1: SEBS (manufactured by Asahi Kasei Corporation, brand name: ToughTec H1062, styrene-derived component content: 18% by mass, MFR (230°C, 2.16 kg load): 4.1 g / 10 min, tanδ peak temperature: -49°C)

[0099] <Ethylene-α-olefin copolymer (D)> D-1: Ethylene-1-butene random copolymer (manufactured by Mitsui Chemicals, brand name: Toughmer A-4050S, MFR (230℃, 2.16kg load): 6.7g / 10min, density: 0.862g / cm³) 3 )

[0100] <Coloring agent (E)> E-1: Carbon Black (Manufactured by Orion Engineered Carbons, Brand Name: HIBLACK 890B) <Inorganic filler (F)> F-1: Talc (manufactured by Asada Flour Milling Co., Ltd., brand name: JM-209, D50: 3.9μm)

[0101] [Examples 1-2, Comparative Examples 1-7] The above components were mixed in the proportions (mass%) shown in Table 1. The resulting mixture was extruded using a twin-screw extruder (Technovel Co., Ltd., KZW-15) under the conditions of a cylinder temperature of 190°C, screw rotation of 500 rpm, and feeder rotation of 40 rpm to obtain a polymer composition. The results of the evaluation method of the obtained polymer composition are also shown in Table 1.

[0102] [Evaluation Method] The following evaluations were performed using the obtained polymer composition. <Melt Flow Rate (MFR)> The MFR (g / 10 min) of the polymer composition was measured according to the measurement method in accordance with ASTM D1238, under conditions of 230°C and a 2.16 kg load. <Specific gravity> The specific gravity of the polymer composition was measured in accordance with ISO 1183, using the water displacement method at a temperature of 23°C.

[0103] <Flexural modulus> Using the polymer composition, test specimens measuring 80 mm (length) x 10 mm (width) x 4 mm (thickness) were prepared by injection molding under the following conditions. Injection molding machine: NEX110, manufactured by Nissei Plastic Industrial Co., Ltd. Cylinder temperature: 195℃ Screw rotation speed: 100 rpm Holding pressure: 45MPa Back pressure: 5 MPa Injection speed: 25mm / s Mold setting temperature: 40℃ Cooling time: 10sec The flexural modulus (MPa) of the test specimen was measured according to the measurement method compliant with ISO 178, under the conditions of a temperature of 23°C, a span distance of 64 mm, and a bending speed of 2 mm / min. <Charpy impact strength> Charpy impact strength (kJ / m²) of the above test specimen measuring 80mm (length) x 10mm (width) x 4mm (thickness) 2 The measurement was performed according to the measurement method compliant with ISO 179-1, under the conditions of a temperature of -30°C, with a notch, and a hammer capacity of 0.5J.

[0104] <Jet Black> Using a polymer composition, a rectangular plate measuring 350 mm × 100 mm × 2 mm in thickness was injection molded under the following conditions. The resulting injection-molded body was used as a test specimen for brightness measurement. Injection molding machine: Sumitomo Heavy Industries, Ltd., SE220HDZ Cylinder temperature: 220℃ Screw rotation speed: 85 rpm Holding pressure: 86MPa Back pressure: 3MPa Injection speed: 25mm / s Mold setting temperature: 40℃ Cooling time: 23sec Using a spectrophotometer (CM-3600A, manufactured by Konica Minolta; integrating sphere type, SCE method, light source: D65), the brightness L in the center of the above test specimen was measured. * This was measured. This brightness L * The smaller the size, the higher the perceived level of jet blackness.

[0105] [Table 1]

Claims

1. A polymer composition, The polymer composition is A propylene homopolymer (A) comprising (a-1) 10 to 80% by mass of a polypropylene portion having an intrinsic viscosity [η] of 5 to 13 dl / g as measured in decalin at 135°C, and (a-2) 90 to 20% by mass of a polypropylene portion having an intrinsic viscosity [η] of less than 5 dl / g as measured in decalin at 135°C, A styrene copolymer elastomer (C) having a styrene-derived constituent unit content of 12 to 20% by mass, and a melt flow rate of 0.1 g / 10 min or more and less than 10 g / 10 min, measured at 230°C and under a 2.16 kg load according to the measurement method compliant with ASTM D1238, and This copolymer is made of ethylene and a carbon-4 α-olefin. According to the ASTM D1238 measurement method, the melt flow rate measured at 230°C and a 2.16 kg load is 0.1–10 g / 10 min, and the density is 0.850–0.895 g / cm³. 3 The ethylene-α-olefin copolymer (D) and A colorant (E) comprising at least one pigment selected from the group consisting of carbon black and organic pigments, Inorganic filler (F), It contains, In the polymer composition, based on the mass of the polymer composition, The content of (A) above is greater than 20% by mass and less than or equal to 97% by mass. The content of (C) is 1% by mass or more and less than 10% by mass, The content of (D) is 1% by mass or more and 35% by mass or less. The content of (E) is 0.01% by mass or more and 2.0% by mass or less. The content of (F) is 0.1% by mass or more and 9.5% by mass or less. Polymer composition.

2. The polymer composition further contains a propylene polymer (B) other than the propylene homopolymer (A), The content of the propylene polymer (B) in the polymer composition is 76% by mass or less, based on the mass of the polymer composition. The polymer composition according to claim 1.

3. The polymer composition according to claim 1, wherein the styrene copolymer elastomer (C) is a hydrogenated block copolymer of styrene and a conjugated diene compound.

4. An injection-molded article formed from the polymer composition according to any one of claims 1 to 3.

5. An injection-molded body according to claim 4, which is an automotive part.

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