Polymer composition and injection molded body

Abstract

This polymer composition comprises: a specific propylene homopolymer (A); a styrene copolymer elastomer (C) which has a content ratio of a styrene-derived constituent unit of 12-20 mass% and a melt flow rate of not less than 0.1 g / 10 minutes but less than 13 g / 10 minutes as measured at 230°C under a load of 2.16 kg; and a coloring agent (D) which contains at least one pigment selected from the group consisting of carbon black and organic pigments. This polymer composition may additionally contain an inorganic filler (E), and the content ratio of each component is in a specific range.

Description

Powder composition and injection molded article

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

[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).

[0003] Japanese Patent Publication No. 2011-116827

[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 object of this disclosure is to provide a polymer composition that is excellent in the expression of color tones such as jet black and can form molded articles with excellent rigidity.

[0005] One embodiment of the polymer composition of the present disclosure contains 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 structural unit content of 12 to 20% by mass and a melt flow rate of 0.1 g / 10 min or more and less than 13 g / 10 min as measured under conditions of 230°C and a 2.16 kg load according to the measurement method in accordance with ISO 1133; and a colorant (D) comprising at least one pigment selected from the group consisting of carbon black and organic pigments, and further comprising an inorganic filler (E). In the above polymer composition, based on the mass of the polymer composition, the content of (A) is greater than 1% 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 0.01% by mass or more and 2.0% by mass or less, and the content of (E) is 0% by mass or more and 19.5% by mass or less.

[0006] One embodiment of the polymer composition of this disclosure is a composition that exhibits excellent color development, such as jet blackness, and can form a molded article with excellent rigidity.

[0007] In this specification, a numerical range expressed using "~" means a range that includes the numbers written before and after "~" as the lower and upper limits. In this specification, if the units of the numbers written before and after the numerical range indicating "~" are the same, the unit of the number written before "~" may be omitted. In this specification, if multiple upper and lower limits are described for a parameter such as a physical property or content, a numerical range obtained by combining any one upper limit and any one lower limit shall also be described as the numerical range of that parameter. As an example, the description "The upper limit of physical property P is preferably U1, more preferably U2, and even more preferably U3. The lower limit of physical property P is preferably L1, more preferably L2, and even more preferably L3." will be explained. In this example, the numerical range of the physical property P may be, for example, L1 to U1, L1 to U2, L1 to U3, L2 to U1, L2 to U2, L2 to U3, L3 to U1, L3 to U2, or L3 to U3.

[0008] In this specification, homopolymers and copolymers are sometimes referred to simply as "polymers." In other words, the term "polymer" can refer to either homopolymers or copolymers.

[0009] [Polymer Composition] One embodiment of the polymer composition of the present disclosure (hereinafter also referred to as "the Composition") contains a propylene homopolymer (A), a styrene copolymer elastomer (C), and a coloring agent (D).

[0010] <Propylene homopolymer (A)> Propylene homopolymer (A) (hereinafter also referred to as "component (A)") comprises: (a-1) 10 to 80% by mass of a polypropylene portion (hereinafter also referred to as "high molecular weight PP 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 (hereinafter also referred to as "low molecular weight PP portion") having an intrinsic viscosity [η] of less than 5 dl / g as measured in decalin at 135°C.

[0011] This composition, which contains component (A) including such high molecular weight PP portion along with the components described later, can form molded articles with an excellent balance of rigidity and impact resistance, and can also form molded articles with excellent color tones, such as jet black. This composition may contain one type of component (A), or two or more types.

[0012] The intrinsic viscosity [η] of the high molecular weight PP portion (a-1), as measured in decalin at 135°C, is 5 to 13 dl / g. The upper limit of [η] is preferably 12 dl / g, more preferably 11 dl / g. The lower limit of [η] is preferably 6 dl / g. When [η] is below the upper limit, the composition becomes a material with excellent fluidity. When [η] is above the lower limit, the composition becomes a material with even better mechanical properties.

[0013] The intrinsic viscosity [η] of the low molecular weight PP portion (a-2), as measured in decalin at 135°C, is less than 5 dl / g. The upper limit of [η] is preferably 4 dl / g, more preferably 3 dl / g. The lower limit of [η] is preferably 0.1 dl / g, more preferably 0.2 dl / g, even more preferably 0.3 dl / g, and particularly preferably 0.5 dl / g. When [η] is below the above upper limit, the composition becomes a material with excellent fluidity. When [η] is above the above lower limit, the low molecular weight PP portion (a-2) has excellent compatibility with the high molecular weight PP portion (a-1), and a molded article with a good appearance can be obtained. The above [η] of the low molecular weight PP portion (a-2) is preferably 0.1 dl / g or more and less than 5 dl / g.

[0014] The content ratio of the high molecular weight PP part (a-1) to the whole component (A) is 10 to 80% by mass. The upper limit of the above content ratio is preferably 70% by mass, more preferably 60% by mass, still more preferably 50% by mass, and particularly preferably 40% by mass. The lower limit of the above content ratio is preferably 12% by mass, more preferably 17% by mass, and still more preferably 20% by mass. When the above content ratio is below the above upper limit, the above composition becomes a material with excellent fluidity. When the above content ratio is above the above lower limit, the above composition is a material with excellent mechanical properties and improved color expression such as jet blackness.

[0015] The content ratio of the low molecular weight PP part (a-2) to the whole component (A) is 90 to 20% by mass. The upper limit of the above content ratio is preferably 88% by mass, more preferably 83% by mass, and still more preferably 80% by mass. The lower limit of the above content ratio is preferably 30% by mass, more preferably 40% by mass, still more preferably 50% by mass, and particularly preferably 60% by mass. When the above content ratio is below the above upper limit, the above composition is a material with excellent mechanical properties and improved color expression such as jet blackness. When the above content ratio is above the above lower limit, the fluidity of the above composition can be improved.

[0016] It is preferable that the total content ratio of the high molecular weight PP part (a-1) and the low molecular weight PP part (a-2) to the whole component (A) is 100% by mass of the whole component (A).

[0017] The upper limit of the intrinsic viscosity [η] measured in decalin at 135 °C of the component (A) containing the high molecular weight PP part (a-1) and the low molecular weight PP part (a-2) is preferably 9 dl / g, more preferably 8 dl / g, and still more preferably 7 dl / g. The lower limit of the above [η] of the component (A) is preferably 1 dl / g, more preferably 1.5 dl / g, and still more preferably 2 dl / g. When the above [η] is below the above upper limit, the fluidity of the above composition can be improved. When the above [η] is above the above lower limit, the above composition is a material with excellent mechanical properties and improved color expression such as jet blackness. The above [η] of the component (A) is preferably 1 to 9 dl / g.

[0018] of component (A) 13The isotactic pentad fraction (mmmm fraction) measured by 13C-NMR is preferably 95% or more, more preferably 97% or more. The mmmm fraction is an index of the stereoregularity of component (A), and the higher this value, the higher the stereoregularity and the better the rigidity.

[0019] The mmmm fraction is 13 an isotactic chain in the pentad unit in the polypropylene molecular chain measured by 13C-NMR, and is the fraction of the propylene monomer unit at the center of the chain in which five consecutive meso bonds are formed with propylene monomer units. Specifically, the mmmm fraction is 13 a value determined as the mmmm peak fraction in the total absorption peak in the methyl carbon region in the 13C-NMR spectrum.

[0020] The upper limit of the melt flow rate (MFR) of component (A) is preferably 50 g / 10 min, more preferably 30 g / 10 min, still more preferably 10 g / 10 min or 5 g / 10 min. The lower limit of the above MFR is preferably 0.01 g / 10 min, more preferably 0.05 g / 10 min, still more preferably 0.1 g / 10 min. When the above MFR is below the above upper limit, a molded article excellent in mechanical properties can be obtained. When the above MFR is above the above lower limit, the above composition is excellent in fluidity and can be molded into large parts. The MFR of component (A) is preferably 0.01 to 50 g / 10 min. The MFR of component (A) is measured under the conditions of 230 °C and a load of 2.16 kg by a measuring method conforming to ISO 1133.

[0021] The upper limit of Mw / Mn of component (A) measured by gel permeation chromatography (GPC) is preferably 30, more preferably 25, still more preferably 20. The lower limit of the above Mw / Mn is preferably 6, more preferably 7, still more preferably 8. When the above Mw / Mn is below the above upper limit, a molded article excellent in mechanical properties can be obtained. When the above Mw / Mn is above the above lower limit, the above composition is excellent in fluidity and can be molded into large parts. Here, Mw is the weight average molecular weight and Mn is the number average molecular weight. The above Mw / Mn is preferably 6 to 30. Details of the measurement conditions of the GPC method will be described later.

[0022] 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. Here, Mz is the z-average molecular weight.

[0023] 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, for example, formed from (i) a solid titanium catalyst component containing magnesium, titanium, halogen, and an electron donor, (ii) an organometallic compound catalyst component, and (iii) an electron donor component, and may be, for example, a polymerization catalyst described in Japanese Patent Application Publication No. 2020-158652.

[0024] Component (A) can be produced by a multi-stage polymerization process of two or more steps, which includes, for example, the step 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 the step of 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.

[0025] The preferred order of carrying out the above steps is to first produce a high molecular weight PP portion (a-1) in the substantially absence of hydrogen in the first step, and then produce a low molecular weight PP portion (a-2) in the second step and beyond. The intrinsic viscosity [η] of the PP portion from the second step onward can be calculated, for example, from the intrinsic viscosity [η] of the PP portion from the first step and the ratio of the amounts of the PP portions from the first step and the second step and beyond. The order of carrying out the above steps 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 molecular weight adjusting agents 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] of the second step and beyond may not increase easily.

[0026] 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 second and subsequent stages of polymerization be carried out continuously following the preceding stage of polymerization. When polymerization is carried out in batches, multi-stage polymerization can also be performed using a single polymerizer.

[0027] 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.

[0028] The propylene homopolymer (A) may contain a structural unit derived from biomass-derived propylene. The propylene constituting the polymer (A) may be only biomass-derived propylene, or may contain both biomass-derived propylene and fossil fuel-derived propylene. Biomass-derived propylene is propylene obtained from any renewable natural raw material such as plant-derived or animal-derived, including fungi, yeast, algae, and bacteria, and its residue, and as carbon 14 contains 13C isotope at a ratio of about 1×10 -12 to 1×10 -14 and has a biomass carbon concentration (pMC) of about 100 (pMC) measured in accordance with ASTM D6866. Biomass-derived propylene is obtained by a conventionally known method. It is preferable from the viewpoint of reducing environmental load (mainly reducing greenhouse gas) that the propylene homopolymer (A) contains a structural unit derived from biomass-derived propylene. 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 14 contains 13C isotope at a ratio of about 1×10 -12 to 1×10 -14 and is equivalent to the propylene homopolymer composed of fossil fuel-derived propylene in terms of molecular structure other than that. Therefore, the performance is also considered to be equivalent.

[0029] The propylene homopolymer (A) may contain constituent units derived from chemically recycled propylene. The propylene constituting the polymer (A) 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. Chemically recycled propylene can be obtained by conventionally known methods. It is preferable for the propylene homopolymer (A) to contain constituent units derived from chemically recycled propylene from the viewpoint of reducing environmental impact (mainly waste reduction). If the polymer production conditions, such as the polymerization catalyst, polymerization process, and polymerization temperature, are equivalent, a propylene homopolymer made from raw material propylene containing chemically recycled propylene is equivalent to a propylene homopolymer made from non-chemically recycled propylene derived from fossil fuels. Therefore, its performance is also considered equivalent.

[0030] <Propylene Polymer (B)> This composition may further contain a propylene polymer other than propylene homopolymer (A) (hereinafter also referred to as "propylene polymer (B)" or "component (B)"). Propylene polymer (B) is not propylene homopolymer (A). This composition may contain one type of component (B) or two or more types.

[0031] 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 C-NMR.

[0032] 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.

[0033] 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.

[0034] The upper limit of the MFR of component (B) is preferably 500 g / 10 min, more preferably 400 g / 10 min, and even more preferably 300 g / 10 min. The lower limit of the MFR of component (B) is preferably 1 g / 10 min, more preferably 3 g / 10 min, even more preferably 5 g / 10 min, and particularly preferably 6 g / 10 min. When the above MFR is below the above upper limit, a molded article with excellent mechanical properties can be obtained. When the above MFR is above the above lower limit, the above composition has excellent fluidity and enables the molding of large parts. The MFR of component (B) is preferably 1 to 500 g / 10 min. The MFR of component (B) is measured under conditions of 230°C and a 2.16 kg load by a measurement method in accordance with ISO 1133.

[0035] 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).

[0036] 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).

[0037] <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.

[0038] The MFR of elastomer (C) is preferably 0.1 g / 10 min or more and less than 13 g / 10 min. The upper limit of the MFR of elastomer (C) is more preferably 10 g / 10 min, even more preferably 8 g / 10 min, and particularly preferably 6 g / 10 min. The lower limit of the MFR of elastomer (C) is more preferably 0.5 g / 10 min, even more preferably 1 g / 10 min, and particularly preferably 2 g / 10 min. If the above MFR is less than or equal to the above upper limit, a molded article with excellent mechanical properties can be obtained. If the above MFR is equal to or greater than the above lower limit, the above composition has excellent fluidity and can be molded into large parts. The MFR is measured under conditions of 230°C and a 2.16 kg load by a measurement method in accordance with ISO 1133.

[0039] The upper limit of the content of styrene-derived structural units in elastomer (C) is preferably 20% by mass, more preferably 19% by mass, and even more preferably 18% by mass, based on the mass of elastomer (C). The lower limit of the content of styrene-derived structural units is preferably 12% by mass, more preferably 13% by mass, and even more preferably 15% by mass. When the content is below the upper limit, the impact resistance of the molded article tends to be better. When the content is above the lower limit, the rigidity of the molded article tends to be better. The content of styrene-derived structural units is preferably 12 to 20% by mass. The content of each structural unit, such as styrene-derived structural units, in elastomer (C) is measured by NMR. By using elastomer (C) in which the content of MFR and styrene-derived structural units, together with component (A) and colorant (D), is within the above-described range, a molded article with the above-described physical properties can be obtained.

[0040] The upper limit of the glass transition temperature (Tg) of the elastomer (C) is preferably 0°C, more preferably -10°C, and even more preferably -20°C. The lower limit of Tg is preferably -90°C, more preferably -80°C, and even more preferably -70°C. When Tg is below the upper limit, the impact resistance of the molded article tends to be excellent. When Tg is above the lower limit, the rigidity of the molded article tends to be excellent. 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: 1 Hz). The Tg is preferably between -90°C and 0°C.

[0041] 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.

[0042] As for the elastomer (C), polymer blocks (C) mainly containing styrene-derived structural units. A ) and polymer blocks (C) mainly containing structural units derived from conjugated diene compounds B At least one selected from the group consisting of a block copolymer having ) and its hydrogenated product is preferred.

[0043] 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) that exist between them B ) or its hydrogenated block is, for example, a soft segment having rubber elasticity.

[0044] A polymer block primarily 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.

[0045] 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.

[0046] Polymer block (C B If the polymer block (C) is formed from butadiene and isoprene, B ) may be any of the following: a random copolymer block of butadiene and isoprene, a block copolymer block, or a tapered copolymer block. Polymer block (C B If the polymer block (C) is formed from butadiene and isoprene, B The content of isoprene-derived constituent units in the product is preferably 40 mol% or more.

[0047] Polymer 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 from 3 to 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 B ) represents. Among these, A (BA) n1The block copolymer represented by is preferred, and the block copolymer represented by ABA is more preferred.

[0048] 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 color tones such as jet blackness, and SEBS is more preferred.

[0049] 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 (the method described in I. M. Kolthoff, et al., J. Polym. Sci. 1,429 (1946)). A It is defined by the following formula using the mass of the polymer block (C). A ) Content ratio (mass%) = [(polymer block (C) in block copolymer before hydrogenation] A (Mass of ) / (Mass of block copolymer before hydrogenation) × 100

[0050] In the above hydrogenated product, polymer block (C BSome 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.

[0051] 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.

[0052] 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.

[0053] <Colorant (D)> This composition contains a colorant (D) comprising at least one pigment selected from the group consisting of carbon black and organic pigments. Since this composition contains a colorant (D) together with a propylene homopolymer (A) and an elastomer (C), it can exhibit a desired color tone. This composition can exhibit jet blackness by containing carbon black and / or a black organic pigment as the colorant (D). Therefore, by using this composition, it is possible to produce molded articles that exhibit a desired color tone (for example, a color tone equivalent to or better than that of a painted product) without painting. This composition may contain one colorant (D), or it may contain two or more colorants.

[0054] 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 upper limit of the average primary particle diameter of the carbon black is preferably 500 nm, more preferably 300 nm, and even more preferably 100 nm. The lower limit of the average primary particle diameter is preferably 5 nm, more preferably 8 nm, and even more preferably 10 nm. When the average primary particle diameter is below the upper limit, the molded article tends to have excellent jet blackness. When the average primary particle diameter is above the lower limit, the carbon black has good dispersibility. The average primary particle diameter is measured by a measurement method in accordance with ASTM D3849-14. The average primary particle diameter is preferably 5 to 500 nm.

[0055] 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.

[0056] Examples of colorants (D) include carbon black, organic pigments, and combinations of carbon black and organic pigments.

[0057] 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.

[0058] <Inorganic Filler (E)> This composition may further contain an inorganic filler (E) from the viewpoint of increasing the rigidity of the molded article. In this specification, the inorganic filler (E) does not formally include carbon black, which is one of the colorants (D) described above. However, this does not prevent the carbon black from functioning as an inorganic filler. This composition may contain one inorganic filler (E), or two or more.

[0059] As the inorganic filler (E), known inorganic fillers can be used. Examples of inorganic fillers (E) 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, and talc is particularly preferred.

[0060] The upper limit of the median diameter (D50) of talc is preferably 15 μm, more preferably 10 μm, and even more preferably 6 μm. The lower limit of D50 is preferably 1 μm, more preferably 2 μm, and even more preferably 3 μm. When D50 is below the upper limit, the rigidity of the molded article tends to be excellent. When D50 is above the lower limit, the dispersibility is good. D50 is preferably 1 to 15 μm. D50 can be 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).

[0061] <Ethylene-α-olefin copolymer (F)> This composition may further contain ethylene-α-olefin copolymer (F) (hereinafter also referred to as "polymer (F)") from the viewpoint of improving the impact resistance of the molded article. The copolymer (F) is preferably a random copolymer. This composition may contain one type of copolymer (F) or two or more types.

[0062] The copolymer (F) is, for example, a copolymer of ethylene and an α-olefin having 3 to 10 carbon atoms. Examples of α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, and 1-decene. Among these, 1-butene is preferred.

[0063] The content of ethylene-derived structural units in copolymer (F) is preferably 70 to 95 mol%, more preferably 75 to 90 mol%, of the total 100 mol% of ethylene-derived structural units and α-olefin-derived structural units having 3 to 10 carbon atoms. The content of the above structural units is 13 It is measured by C-NMR.

[0064] The upper limit of the MFR of copolymer (F) is preferably 10 g / 10 min, more preferably 9 g / 10 min, and even more preferably 8 g / 10 min. The lower limit of the MFR of copolymer (F) is preferably 0.1 g / 10 min, more preferably 0.3 g / 10 min, and even more preferably 0.5 g / 10 min. When the above MFR is below the above upper limit, a molded article with excellent mechanical properties can be obtained. When the above MFR is above the above lower limit, the above composition has excellent fluidity and enables the molding of large parts. The MFR of copolymer (F) is preferably 0.1 to 10 g / 10 min. The MFR of copolymer (F) is measured under conditions of 230°C and a 2.16 kg load by a measurement method in accordance with ISO 1133.

[0065] The upper limit of the intrinsic viscosity [η] of copolymer (F), as measured in decalin at 135°C, is preferably 5.0 dl / g, more preferably 4.0 dl / g, and even more preferably 3.0 dl / g. The lower limit of the above [η] for copolymer (F) is preferably 0.1 dl / g, more preferably 0.3 dl / g, and even more preferably 0.5 dl / g. When the above [η] is below the above upper limit, the above composition has excellent fluidity and can be molded into large parts. When the above [η] is above the above lower limit, a molded article with excellent mechanical properties can be obtained. The above [η] for copolymer (F) is preferably 0.1 to 5.0 dl / g.

[0066] The density of the copolymer (F) is preferably 0.850 to 0.895 g / cm³. 3 A more preferable concentration is 0.855 to 0.875 g / cm³. 3 This is the case. Copolymers (F) having such density contribute 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 (F) obtained during MFR measurement at 120°C for 1 hour and then slowly cooling it to room temperature (23°C) over 1 hour.

[0067] Copolymer (F) can be produced by conventionally known methods. The MFR can be adjusted, for example, by adjusting the ratio of the amount of hydrogen gas fed as a chain transfer agent to the amount of ethylene and α-olefin fed when copolymerizing ethylene and α-olefin to produce copolymer (F). That is, the MFR can be increased by increasing this ratio, and the MFR can be decreased by decreasing this ratio.

[0068] 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 α-olefin to produce a copolymer (F). In other words, increasing this ratio can lower the density, and decreasing this ratio can increase the density.

[0069] <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.

[0070] 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].

[0071] 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.

[0072] This composition may contain one or more additives. When using two or more additives, the mixing order of the two or more 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.

[0073] <Content Ratio 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, that is, they represent the content ratio in 100% by mass of this composition. The content ratio of propylene homopolymer (A) in this composition is preferably greater than 1% by mass and 97% by mass or less, more preferably 1.5 to 97% by mass, even more preferably 10 to 94% by mass, and particularly preferably 15 to 93% by mass. The content ratio of component (A) may be, for example, 10% by mass or more, 15% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, or 70% by mass or more. When the content ratio of component (A) is greater than or equal to the above lower limit, the resulting molded article has excellent rigidity.

[0074] The total content of the propylene homopolymer (A), propylene polymer (B), styrene copolymer elastomer (C), colorant (D), and inorganic filler (E) in this composition is preferably 85% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0075] The upper limit of the content of component (B) in this composition is preferably 76% by mass, more preferably 60% by mass, even more preferably 42% by mass, and particularly preferably 23% by mass. The lower limit of the content of component (B) is preferably 0% by mass, more preferably 5% by mass, even more preferably 10% by mass, and particularly preferably 15% by mass. If the content of component (B) is below the above upper limit, a molded article with excellent rigidity can be obtained. If the content of component (B) is above the above lower limit, a molded article with excellent impact resistance can be obtained.

[0076] The content of elastomer (C) in this composition is preferably 1% by mass or more and less than 10% by mass. The upper limit of the elastomer (C) content is more preferably 9.4% by mass, even more preferably 9.3% by mass, and particularly preferably 9.2% by mass. The lower limit of the elastomer (C) content is more preferably 2% by mass, even more preferably 5% by mass, and particularly preferably 6% by mass. If the above content is less than or equal to the above upper limit, a molded article with excellent rigidity can be obtained. If the above content is greater than or equal to the above lower limit, a molded article with excellent color tone such as jet blackness and impact resistance can be obtained.

[0077] The content of the colorant (D) in this composition is preferably 0.01 to 2.0% by mass. The upper limit of the content of the colorant (D) is more preferably 1.8% by mass, even more preferably 1.6% by mass, and particularly preferably 1.5% by mass. The lower limit of the content of the colorant (D) is more preferably 0.03% by mass, even more preferably 0.1% by mass, and particularly preferably 0.5% by mass. If the above content is below the upper limit, the deterioration of mechanical properties can be suppressed. If the above content is above the lower limit, the composition becomes a material with improved color expression, such as jet blackness.

[0078] The content of inorganic filler (E) in this composition is preferably 0 to 19.5% by mass. The upper limit of the content of inorganic filler (E) is more preferably 19% by mass, even more preferably 7% by mass, and particularly preferably 6% by mass. The lower limit of the content of inorganic filler (E) is more preferably 0.1% by mass, even more preferably 0.5% by mass, and particularly preferably 1% by mass. When the content of inorganic filler (E) is below the upper limit, the resulting molded article has excellent color tone, for example, jet blackness. When the content of inorganic filler (E) is above the lower limit, the resulting molded article has excellent rigidity.

[0079] The content of copolymer (F) in this composition is preferably 0 to 35% by mass. The upper limit of the content of copolymer (F) is more preferably 20% by mass, even more preferably 10% by mass, and particularly preferably 9% by mass. The lower limit of the content of copolymer (F) is more preferably 0.1% by mass, even more preferably 0.5% by mass, and particularly preferably 1% by mass. When the content of copolymer (F) is below the upper limit, the resulting molded article has excellent rigidity. When the content of copolymer (F) is above the lower limit, the resulting molded article has excellent impact resistance.

[0080] The content of antioxidants in this composition is preferably 0 to 1.5% by mass, more preferably 0 to 1% by mass, and when antioxidants are added, it is preferably 0.1 to 1.5% by mass, more preferably 0.1 to 1% by mass. The content of weather stabilizers in this composition is preferably 0 to 1.5% by mass, more preferably 0 to 1% by mass, and when weather stabilizers are added, it is preferably 0.1 to 1.5% by mass, more preferably 0.1 to 1% by mass. The content of dispersants in this composition is preferably 0 to 2.0% by mass, more preferably 0 to 1.5% by mass, and when dispersants are added, it is preferably 0.1 to 2.0% by mass, more preferably 0.1 to 1.5% by mass. The content of nucleating agents in this composition is preferably 0 to 1.5% by mass, more preferably 0 to 1% by mass, and when nucleating agents are 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.

[0081] The total content of additives in this composition is preferably 0 to 10% by mass, more preferably 0 to 9% by mass, and even more preferably 0 to 7.5% by mass.

[0082] <Physical Properties of Polymer Composition> The upper limit of the MFR of this composition is preferably 50 g / 10 min, more preferably 30 g / 10 min, and even more preferably 10 g / 10 min. The lower limit of the MFR of this composition is preferably 0.01 g / 10 min, more preferably 0.1 g / 10 min, and even more preferably 1 g / 10 min. When the above MFR is below the above upper limit, a molded article with excellent mechanical properties can be obtained. When the above MFR is above the above lower limit, the above composition has excellent fluidity and can be molded into large parts. The MFR of this composition is preferably 0.01 to 50 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 ISO 1133.

[0083] The upper limit of the flexural modulus of this composition at 23°C is preferably 2500 MPa, more preferably 2450 MPa, and even more preferably 2400 MPa. The lower limit of the flexural modulus is preferably 1900 MPa, more preferably 1940 MPa, and even more preferably 2000 MPa. If the flexural modulus is below the upper limit, a molded article with excellent impact resistance can be formed. If the flexural modulus is above the lower limit, a molded article with excellent rigidity can be formed. The flexural modulus is preferably 1900 to 2500 MPa. The flexural modulus is measured by a measurement method in accordance with ISO 178, and details of the measurement conditions are described in the Examples section. The upper limit of the Charpy impact strength of this composition at -30°C is preferably 7.0 kJ / m 2 More preferably 6.5 kJ / m 2 More preferably 6.0 kJ / m 2 The lower limit of the Charpy impact strength is preferably 1.5 kJ / m². 2 More preferably 1.7 kJ / m 2 More preferably 1.9 kJ / m 2 The above Charpy impact strength is less than or equal to the above upper limit, which allows for the formation of a molded article with excellent rigidity. The above Charpy impact strength is greater than or equal to the above lower limit, which allows for the formation of a molded article with excellent impact resistance. The above Charpy impact strength is preferably 1.5 to 7.0 kJ / m 2The 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.

[0084] The brightness L of the central portion of an injection-molded body measuring 350 mm x 100 mm x 2 mm in thickness, obtained by injection molding this composition under the conditions described in the Examples section. ＊ The upper limit is preferably 7.0, more preferably 6.5, and even more preferably 6.0 in one embodiment. ＊ The lower limit is preferably 4.5, more preferably 4.7, and even more preferably 4.9. ＊ If L is below the above upper limit, a molded article with excellent rigidity can be formed. ＊ If the above lower limit is greater than or equal to the above lower limit, a molded body with excellent jet blackness can be formed. ＊ The value is preferably between 4.5 and 7.0.

[0085] <Method for producing the polymer composition> This composition can be produced, for example, by mixing a propylene homopolymer (A), a styrene copolymer elastomer (C), a colorant (D), and, if necessary, at least one selected from the group consisting of a propylene polymer (B), an inorganic filler (E), an ethylene-α-olefin copolymer (F), and an additive.

[0086] 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.

[0087] 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.

[0088] [Molded Article] This composition can be molded by conventionally known molding methods for molding 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.

[0089] 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.

[0090] In recent years, there has been a demand for unpainted molded articles from the perspective of reducing volatile organic compounds (VOCs) and costs. Unpainted molded articles require not only the same physical properties as painted molded articles (e.g., high rigidity, high impact resistance), but also high color development when a coloring agent is added, as is sometimes required for unpainted molded articles. As described above, this composition can exhibit desired colors such as jet black by combining the above components with a coloring agent (D). Furthermore, this composition can form molded articles with excellent rigidity and impact resistance. In addition, when the above molded article is unpainted, it also has excellent recyclability.

[0091] The above-mentioned molded body may be painted.

[0092] [Examples of Embodiments] 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 13 g / 10 min as measured by a measurement method in accordance with ISO 1133 under conditions of 230°C and a 2.16 kg load; and a colorant (D) comprising at least one pigment selected from the group consisting of carbon black and organic pigments, wherein the polymer composition may further contain an inorganic filler (E). [1] The polymer composition wherein, with respect to the mass of the polymer composition, the content of (A) is greater than 1% 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 0.01% by mass or more and 2.0% by mass or less, and the content of (E) is 0% by mass or more and 19.5% 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 of the propylene polymer (B) in the polymer composition is 76% by mass or less, with respect to 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 the polymer composition according to any one of [1] to [3]. [5] The injection molded article described in [4] above, which is an automobile part.

[0093] 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.

[0094] [Measurement Conditions for 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 Inc.) Analysis software: Chromatography data system Empower (Waters Inc.) Column: TSKgel GMH6-HT x 2 + TSKgel GMH6-HT x 2 (inner diameter 7.5 mm x length 30 cm, Tosoh Corporation) Mobile phase: o-dichlorobenzene (Wako Pure Chemical Industries, Ltd., special grade reagent) Detector: Differential refractometer (built into the device) Column temperature: 140°C Flow rate: 1.0 mL / min Injection volume: 400 μL 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

[0095] [Measurement conditions for intrinsic viscosity [η]] The intrinsic viscosity [η] of the target polymer was measured in decalin at 135°C according to a conventional method. 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)

[0096] [Production Example 1] Propylene Homopolymer (A-1) (Preparation of Solid Catalyst Component) 10 g of diethoxymagnesium and 500 ml of toluene were placed in a 500 ml round-bottom flask equipped with a stirrer and thoroughly purged with nitrogen gas to form a suspension. 500 ml of titanium tetrachloride at room temperature 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, where 15 ml of diethyl phthalate was added. The temperature in the system was then raised to 115°C, and 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, and 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.

[0097] (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 the prepolymerization catalyst.

[0098] (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 dicyclopentyldimethoxysilane at 37.2 g / hour, and propylene was charged while maintaining the internal pressure of polymerizer (1) at 0.69 MPa at a temperature of 60°C under conditions where hydrogen was substantially absent (first stage polymerization). The slurry from polymerizer (1) was sampled, and the intrinsic viscosity [η] of polypropylene was measured to be 9.1 dl / g.

[0099] 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).

[0100] 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.

[0101] The crystalline propylene homopolymer (A-1) had an MFR (at 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 its intrinsic viscosity [η] was 0.5 dl / g.

[0102] The components used in the following examples and comparative examples are listed below. <Propylene Polymer (B)> B-1: Propylene homopolymer MFR = 9 g / 10 min B-2: Propylene homopolymer MFR = 200 g / 10 min B-3: Propylene homopolymer MFR = 30 g / 10 min <Styrene Copolymer Elastomer (C)> C-1: SEBS (manufactured by Asahi Kasei Corporation, brand name: ToughTec H1062, styrene-derived constituent unit content: 18% by mass, MFR (230°C, 2.16 kg load): 4.1 g / 10 min, tanδ peak temperature: -49°C)

[0103] <Coloring agent (D)> D-1: Carbon black (manufactured by Orion Engineered Carbons, brand name: HIBLACK 890B) <Inorganic filler (E)> E-1: Talc (manufactured by Asada Flour Milling Co., Ltd., brand name: JM-209, D50: 3.9 μm)

[0104] <Ethylene-α-olefin copolymer (F)> F-1: Ethylene-1-butene random copolymer (manufactured by Mitsui Chemicals, brand name: Tuffmer A-4050S, MFR (230℃, 2.16 kg load): 6.7 g / 10 min, density: 0.862 g / cm³) 3 )

[0105] [Examples 1-4, Comparative Examples 1-4] 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 methods for the obtained polymer compositions are also shown in Table 1.

[0106] [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 at 230°C and under a 2.16 kg load, according to the measurement method in accordance with ISO 1133. <Specific Gravity> The specific gravity of the polymer composition was measured at 23°C by the water displacement method, according to ISO 1183.

[0107] <Flexural Modulus> Using a polymer composition, a test specimen measuring 80 mm (length) x 10 mm (width) x 4 mm (thickness) was prepared by injection molding under the following conditions. Injection molding machine: NEX110, manufactured by Nissei Plastic Industrial Co., Ltd. Cylinder temperature: 195°C Screw rotation speed: 100 rpm Holding pressure: 45 MPa Back pressure: 5 MPa Injection speed: 25 mm / s Mold setting temperature: 40°C Cooling time: 10 sec The flexural modulus (MPa) of the test specimen was measured according to the measurement method in accordance 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> The Charpy impact strength (kJ / m) of the above test specimen measuring 80 mm (length) x 10 mm (width) x 4 mm (thickness) was measured. 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 0.5 J.

[0108] <Jet Blackness> Using a polymer composition, a 350 mm x 100 mm x 2 mm thick rectangular plate was injection molded under the following conditions. The obtained injection molded body was used as a test piece for brightness measurement. Injection molding machine: Sumitomo Heavy Industries, Ltd., SE220HDZ Cylinder temperature: 220°C Screw rotation speed: 85 rpm Holding pressure: 86 MPa Back pressure: 3 MPa Injection speed: 25 mm / s Mold setting temperature: 40°C Cooling time: 23 sec Using a SPECTROPHOTOMETER (CM-3600A, Konica Minolta; integrating sphere type, SCE method, light source: D65), the brightness L in the center of the above test piece was measured. ＊ This was measured. This brightness L ＊ The smaller the size, the higher the perceived level of jet blackness.

[0109]

Claims

1. A polymer composition comprising: a propylene homopolymer (A) comprising (a-1) 10 to 80% by mass of polypropylene 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 polypropylene 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 13 g / 10 min as measured by a measurement method in accordance with ISO 1133 under conditions of 230°C and a 2.16 kg load; and a colorant (D) comprising at least one pigment selected from the group consisting of carbon black and organic pigments, wherein the polymer composition may further contain an inorganic filler (E), and in the polymer composition, based on the mass of the polymer composition, A polymer composition wherein the content of (A) is greater than 1% 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 0.01% by mass or more and 2.0% by mass or less, and the content of (E) is 0% by mass or more and 19.5% by mass or less.

2. The polymer composition according to claim 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 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 article according to claim 4, which is an automotive part.

Images