Resin composition and molded article

Abstract

To provide a resin composition having improved transparency and excellent impact resistance.SOLUTION: A resin composition comprising: polypropylene; and a propylene - α - olefin copolymer.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a propylene-based resin composition and a molded article formed from the propylene-based resin composition. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-36390 Summary of the Invention [Problem to be solved by the invention]

[0004] Molded articles of conventional resin compositions have insufficient impact resistance. Furthermore, it is known that the inclusion of an ethylene-α-olefin copolymer in a resin composition reduces transparency. Therefore, there is a demand for resin compositions that have improved transparency and excellent impact resistance. The present disclosure has an object to provide a resin composition having improved transparency and excellent impact resistance. The present disclosure can be realized in the following aspects. [Means for solving the problem]

[0005] [1] Polypropylene, a propylene-α-olefin copolymer; A resin composition comprising: [Effects of the Invention]

[0006] According to the present disclosure, a resin composition having improved transparency and excellent impact resistance can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0007] Here, a preferred example of the present disclosure will be described. [2] The resin composition according to [1], which contains an inorganic pigment and / or a black colorant. [3] The resin composition according to [2], wherein the black colorant contains carbon black and / or an organic dye. [4] The resin composition according to any one of [1] to [3], which contains a resin clarifying agent. [5] The resin composition according to any one of [1] to [4], wherein the haze at a thickness of 2 mm according to JIS K 7136:2000 is 40% or less. [6] A molded article of the resin composition according to any one of [1] to [5]. [7] L* value based on JIS Z 8781-4:2013 is 2.5 or less, and / or Charpy impact strength at 23°C based on JIS K 7111 is 5.0 kJ / m 2 The molded article according to [6] above.

[0008] The present disclosure will be described in detail below. 1. First embodiment The resin composition of the first embodiment contains polypropylene and a propylene-α-olefin copolymer. The resin composition preferably contains an inorganic pigment and / or a black colorant.

[0009] 1-1. Components of resin composition (1) Polypropylene The polypropylene is preferably one or more types selected from the group consisting of random polypropylene, block polypropylene, and homopolypropylene. Among these, from the viewpoint of flexibility and impact resistance, the polypropylene preferably includes block polypropylene. Only one type of polypropylene may be used, or two or more types may be used in combination.

[0010] The melting point of polypropylene is preferably 90° C. or higher and 170° C. or lower, more preferably 100° C. or higher and 160° C. or lower, and even more preferably 110° C. or higher and 150° C. or lower. The melting point of polypropylene is determined from the exothermic-endothermic curve obtained in a differential scanning calorimeter (DSC) measurement device under a nitrogen atmosphere, by increasing the temperature from −60° C. to 200° C. at a rate of 10° C. / min, holding at 200° C. for 5 minutes, decreasing the temperature from 200° C. to −60° C. at a rate of 10° C. / min, holding at −60° C. for 5 minutes, and then increasing the temperature from −60° C. to 200° C. at a rate of 10° C. / min.

[0011] The polypropylene content is preferably 70 parts by mass or more, more preferably 75 parts by mass or more, and even more preferably 80 parts by mass or more, when the total of the resin raw materials (polypropylene and propylene-α-olefin copolymer, the same applies hereinafter) is 100 parts by mass. The polypropylene content is preferably 97 parts by mass or less, more preferably 95 parts by mass or less, and even more preferably 90 parts by mass or less. From these viewpoints, the polypropylene content is preferably 70 parts by mass or more and 97 parts by mass or less, more preferably 75 parts by mass or more and 95 parts by mass or less, and even more preferably 80 parts by mass or more and 90 parts by mass or less.

[0012] Examples of random polypropylenes include propylene-ethylene random copolymers (for example, metallocene PP polymerized by a metallocene catalyst).

[0013] The melt flow rate of the random polypropylene (JIS K7210, 230°C, 2.16 kg) is not particularly limited. From the viewpoint of moldability, the melt flow rate of the random polypropylene is preferably 1 g / 10 min or more and 200 g / 10 min or less, more preferably 10 g / 10 min or more and 150 g / 10 min or less, and even more preferably 25 g / 10 min or more and 100 g / 10 min or less.

[0014] The content of the random polypropylene is preferably 30 parts by mass or more, more preferably 35 parts by mass or more, and even more preferably 40 parts by mass or more, when the total amount of the resin raw materials is 100 parts by mass, from the viewpoint of improving transparency. From the viewpoint of ensuring impact resistance, the content of the random polypropylene is preferably 90 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 50 parts by mass or less. From these viewpoints, the content of the random polypropylene is preferably 30 parts by mass or more and 90 parts by mass or less, more preferably 35 parts by mass or more and 70 parts by mass or less, and even more preferably 40 parts by mass or more and 50 parts by mass or less.

[0015] Block polypropylene is a polymer with a sea-island structure in which an ethylene-based resin is dispersed in polypropylene. Block polypropylene is a type of propylene block copolymer in the broad sense. Block polypropylene is a polymer that contains, for example, approximately 10% by mass to 50% by mass of island phases of polyethylene components and / or ethylene-propylene copolymer components in a polypropylene sea phase, and is also called a heterophase copolymer. Unlike ethylene-propylene block copolymers in the narrow sense, homopolypropylene chains and polyethylene chains or ethylene-propylene copolymer chains are not necessarily chemically bonded. In general block polypropylene, polyethylene island phases are dispersed in a polypropylene sea phase while being covered with ethylene-propylene copolymer.

[0016] The heterophase copolymer described above can be produced, for example, by first polymerizing propylene homopolymer and then copolymerizing ethylene or the like. The sea-island structure can be controlled by adjusting the ratio of the ethylene component, the number of chains, and the molecular weight of the PP. Various products are commercially available, and any type of block polypropylene can be used in the present disclosure. Block polypropylenes generally have excellent flexibility and impact resistance. It is believed that the use of block polypropylene can contribute to improvements in flexibility, impact resistance, and the like, compared to the use of, for example, propylene homopolymer or narrowly defined ethylene-propylene block copolymer. Only one type of block polypropylene may be used, or two or more types may be used in combination.

[0017] The melt flow rate of the block polypropylene (based on JIS K7210, 230°C, 2.16 kg) is not particularly limited. From the viewpoint of moldability, the melt flow rate of the block polypropylene is preferably 1 g / 10 min or more and 200 g / 10 min or less, more preferably 10 g / 10 min or more and 150 g / 10 min or less, and even more preferably 25 g / 10 min or more and 100 g / 10 min or less.

[0018] The density of the block polypropylene is not particularly limited. The density of the block polypropylene is 0.89 g / cm 3 More than 0.92g / cm 3 The density can be measured as follows: The density is measured in accordance with JIS K7112.

[0019] The content of the block polypropylene is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more, when the total amount of the resin raw materials is 100 parts by mass, from the viewpoint of improving impact resistance. From the viewpoint of ensuring transparency, the content of the block polypropylene is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less. From these viewpoints, the content of the block polypropylene is preferably 20 parts by mass or more and 70 parts by mass or less, more preferably 30 parts by mass or more and 60 parts by mass or less, and even more preferably 40 parts by mass or more and 50 parts by mass or less.

[0020] (2) Propylene-α-olefin copolymer The propylene-α-olefin copolymer is a copolymer having structural units derived from propylene and structural units derived from at least one α-olefin selected from α-olefins having 4 to 10 carbon atoms. Examples of the α-olefins having 4 to 10 carbon atoms include one or more selected from the group consisting of 1-butene, 1-octene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-decene, and α-olefins having a cyclic structure. 1-butene is preferred as the α-olefin.

[0021] In the propylene-α-olefin copolymer, the content of the structural units derived from propylene and the content of the structural units derived from the above-mentioned α-olefin are not particularly limited.

[0022] The propylene-α-olefin copolymer may have structural units derived from ethylene in addition to structural units derived from propylene and the above-mentioned structural units derived from the α-olefin.

[0023] The propylene-α-olefin copolymer does not include a graft polymer having a side chain made of a propylene polymer.

[0024] The melting point of the propylene-α-olefin copolymer is preferably 120° C. or higher and 190° C. or lower, more preferably 130° C. or higher and 180° C. or lower, and even more preferably 140° C. or higher and 170° C. or lower. The melting point of the propylene-α-olefin copolymer is determined from the exothermic-endothermic curve obtained by heating the copolymer in a differential scanning calorimeter (DSC) measurement device in a nitrogen atmosphere from −60° C. to 200° C. at a heating rate of 10° C. / min, holding the copolymer at 200° C. for 5 minutes, cooling the copolymer from 200° C. to −60° C. at a heating rate of 10° C. / min, holding the copolymer at −60° C. for 5 minutes, and then heating the copolymer from −60° C. to 200° C. at a heating rate of 10° C. / min.

[0025] The melt flow rate of the propylene-α-olefin copolymer (based on ASTM D1238, 230°C, 2.16 kg) is not particularly limited. From the viewpoint of moldability, the melt flow rate of the ethylene-α-olefin copolymer is preferably 1 g / 15 min to 9 g / 10 min, more preferably 3 g / 10 min to 10 g / 10 min, and even more preferably 5 g / 10 min to 7 g / 10 min.

[0026] The density of the propylene-α-olefin copolymer is not particularly limited. The density of the propylene-α-olefin copolymer is 0.85 g / cm 3 More than 0.90g / cm 3 The density can be measured as follows: The density is measured in accordance with ASTM D1505.

[0027] The content of the propylene-α-olefin copolymer is preferably 2 parts by mass or more, more preferably 5 parts by mass or more, and even more preferably 7 parts by mass or more, from the viewpoint of improving impact resistance, when the total amount of the resin raw materials is 100 parts by mass. From the viewpoint of ensuring rigidity, the content of the propylene-α-olefin copolymer is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 16 parts by mass or less. From these viewpoints, the content of the propylene-α-olefin copolymer is preferably 3 parts by mass or more and 30 parts by mass or less, more preferably 5 parts by mass or more and 20 parts by mass or less, and even more preferably 7 parts by mass or more and 16 parts by mass or less.

[0028] (3) Black colorant The black colorant may be either a black pigment or a black dye, and preferably includes carbon black and / or an organic dye.

[0029] The type of carbon black is not particularly limited, and the carbon black may be, for example, one or more types selected from the group consisting of furnace black, ketjen black, and acetylene black.

[0030] The average particle size of carbon black is preferably 3 nm or more, more preferably 5 nm or more, and even more preferably 8 nm or more, from the viewpoint of facilitating mixing in the resin composition. The average particle size of carbon black is preferably 40 nm or less, more preferably 30 nm or less, and even more preferably 20 nm or less, from the viewpoint of imparting a jet black feel to the resin composition. From these viewpoints, the average particle size of carbon black is preferably 3 nm or more and 40 nm or less, more preferably 5 nm or more and 30 nm or less, and even more preferably 8 nm or more and 20 nm or less.

[0031] The carbon black content is preferably 0.25 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 0.8 parts by mass or more, from the viewpoint of imparting a jet-black appearance to the resin composition, when the total amount of the resin raw materials is 100 parts by mass. From the viewpoint of maintaining moldability, the carbon black content is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less. From these viewpoints, the carbon black content is preferably 0.25 parts by mass or more and 5 parts by mass or less, more preferably 0.5 parts by mass or more and 3 parts by mass or less, and even more preferably 0.8 parts by mass or more and 2 parts by mass or less.

[0032] (4) Inorganic pigments The inorganic pigment has a function of imparting a metallic color tone to the resin composition, and examples of the inorganic pigment include metallic pigments, spherical aluminum pigments, mica powder, and metal-coated inorganic polyhedral particles.

[0033] Metallic pigments are flat pigments such as aluminum foils or glass flakes coated with a metal. Spherical aluminum pigments are used to improve the appearance of welds. Mica powder is a pearlescent metallic pigment. Metal-coated inorganic polyhedral particles are inorganic polyhedral particles such as copper powder, brass powder, or glass coated with a metal by plating or sputtering to obtain a bronze color tone.

[0034] Examples of the inorganic polyhedral particles include glass, crushed thin glass films, and metals. Examples of metals include Ni, Al, Ag, Cu, Cr, Zn, Sn, Pb, Co, Fe, Mo, Mn, W, Au, Ti, Sb, Si, Pt, and Mg. At least one metal selected from these metals, or compounds thereof such as alloys, oxides, nitrides, and sulfides, or mixtures thereof, can be used.

[0035] As described above, inorganic pigments are metals or metal compounds themselves, or metals or metal compounds attached to glass, mica, or the like by plating, vapor deposition, or other methods. Inorganic pigments also include those coated with organic substances such as fatty acids to protect the metal surface, or with titanium oxide, silica, or the like. Since the color tone of the resulting metallic resin molded product varies depending on the inorganic pigment used, the inorganic pigment is appropriately selected and used depending on the desired color tone. Furthermore, the desired color tone can be achieved by combining an inorganic pigment with an existing colorant typically blended into resins and adjusting the type and amount of each.

[0036] The inorganic pigment preferably contains one or more selected from the group consisting of mica, alumina, aluminum, and silica.

[0037] The content of the inorganic pigment is not particularly limited. When the total amount of the resin raw materials is 100 parts by mass, the content of the inorganic pigment is preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, and even more preferably 3.0 parts by mass or less, from the viewpoint of suppressing deterioration of physical properties and molding defects of molded articles using the resin composition. The content of the inorganic pigment is preferably 0.05 parts by mass or more, more preferably 0.08 parts by mass or more, and even more preferably 0.1 parts by mass or more, from the viewpoint of obtaining a sufficient color tone due to the inorganic pigment. From these viewpoints, the content of the inorganic pigment is preferably 0.05 parts by mass or more and 5.0 parts by mass or less, more preferably 0.08 parts by mass or more and 4.0 parts by mass or less, and even more preferably 0.1 parts by mass or more and 3.0 parts by mass or less.

[0038] Inorganic pigments are usually present in the form of fine powder, and from the viewpoints of preventing dust explosions, improving the working environment, etc., inorganic pigments may be used in the form of a so-called masterbatch in which the inorganic pigment is pre-mixed with an olefin-based resin, etc. There are no particular restrictions on the amount of inorganic pigment contained in the masterbatch, but it is, for example, 10% by weight or more and 90% by weight or less.

[0039] (5) Dispersant The resin composition preferably contains a dispersant. Examples of dispersants that can be used include polyethylene wax, ester wax, and fatty acid metal soaps. The number-average molecular weight of the polyethylene wax is preferably 300 or more and 8000 or less, and more preferably 1000 or more and 5000 or less. Low-molecular-weight polyethylene and its derivatives can be used as the polyethylene wax. If the number-average molecular weight of the polyethylene wax is less than 300, the pigment dispersibility is excellent, but the processability tends to be reduced. On the other hand, if the number-average molecular weight of the polyethylene wax exceeds 8000, the processability tends to be reduced. Examples of fatty acid metal soaps include zinc stearate, calcium stearate, lithium stearate, magnesium stearate, and sodium palmitate.

[0040] The content of the dispersant is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.1 parts by mass or more, when the total amount of the resin raw materials is 100 parts by mass. The content of the dispersant is preferably 1.0 part by mass or less, more preferably 0.8 parts by mass or less, and even more preferably 0.5 parts by mass or less. Therefore, the content of the dispersant is preferably 0.1 part by mass or more and 1.0 part by mass or less, more preferably 0.05 parts by mass or more and 0.8 parts by mass or less, and even more preferably 0.1 part by mass or more and 0.5 parts by mass or less.

[0041] (6) Antioxidants The resin composition preferably contains an antioxidant, such as a hindered phenol-based antioxidant, a phosphorus-based antioxidant, a hindered amine-based antioxidant, or a sulfur-based antioxidant, and among these, hindered phenol-based antioxidants and phosphorus-based antioxidants are preferred.

[0042] Examples of hindered phenol antioxidants include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and the like. 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), 4-methyl-2,6-di-t-butylphenol, triethylene glycol bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-, C7-C9 side chain alkyl ester, 2,4-bis[(octylthio)methyl]-o-cresol, 2,4-bis[(dodecylthio)methyl]-6-methylphenol, 3,9-bis[1,1-dimethyl-2-[(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane, and the like. Among these, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] is preferred.

[0043] Examples of phosphorus-based antioxidants include tris(2-ethylhexyl) phosphite, tris(dipropylene glycol) phosphite, triphenyl phosphite, tristearyl phosphite, and bis(tridecyl)pentaerythritol diphosphite.

[0044] The content of the antioxidant is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.08 parts by mass or more, when the total amount of the resin raw materials is 100 parts by mass. The content of the antioxidant is preferably 0.20 parts by mass or less, more preferably 0.15 parts by mass or less, and even more preferably 0.12 parts by mass or less. Therefore, the content of the antioxidant is preferably 0.01 parts by mass or more and 0.20 parts by mass or less, more preferably 0.05 parts by mass or more and 0.15 parts by mass or less, and even more preferably 0.08 parts by mass or more and 0.12 parts by mass or less.

[0045] (7) Weatherproofing agent The resin composition preferably contains a weathering agent. A weathering agent is an additive for suppressing deterioration of the resin composition due to outdoor natural environments such as sunlight, temperature, humidity, and rain. Examples of weathering agents include ultraviolet absorbers for absorbing ultraviolet rays and light stabilizers for stabilizing radicals generated by ultraviolet rays. The resin composition of the present disclosure may contain any one of these weathering agents, or may contain two or more of them.

[0046] As the weatherproofing agent, for example, a NOR type hindered amine compound is preferably used. A light stabilizer containing a NOR type hindered amine compound as the main component is, for example, a mixture of a high molecular weight hindered amine light stabilizer and a sterically hindered hindered amine light stabilizer, and a low basicity weatherproofing stabilizer system can be preferably used. Note that the NOR type hindered amine compound is a hindered amine compound in which the H of the imino group (>NH) of the piperidine ring is substituted with an alkoxyl group (-OR).

[0047] The content of the weather resistant agent is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.08 parts by mass or more, when the total amount of the resin raw materials is 100 parts by mass. The content of the weather resistant agent is preferably 1.00 parts by mass or less, more preferably 0.75 parts by mass or less, and even more preferably 0.50 parts by mass or less. Therefore, the content of the weather resistant agent is preferably 0.01 parts by mass or more and 1.00 parts by mass or less, more preferably 0.05 parts by mass or more and 0.75 parts by mass or less, and even more preferably 0.08 parts by mass or more and 0.50 parts by mass or less.

[0048] (8) Resin clarifying agent The resin composition may contain a resin clarifying agent. The resin clarifying agent functions to make the resin transparent. By containing a resin clarifying agent in the resin composition, the transparency of the resin composition can be increased. Examples of resin clarifying agents include the following. Milliken Millad NX 8000 (Bis(4-propylbenzylidene) propyl sorbitol) ADEKA TRANSPAREX CA-2407 New Japan Chemical Gelall DXR

[0049] (9) Other ingredients The resin composition may contain a release agent, a filler, a processing aid, a lubricant, a pigment other than carbon black, a function-imparting agent (for example, a flame retardant), and the like, as needed.

[0050] (10) Melt flow rate of resin composition From the viewpoint of moldability, the melt flow rate of the resin composition (according to JIS K 7210, 230°C, 2.16 kg) is preferably 15 g / 10 min or more and 35 g / 10 min or less, more preferably 20 g / 10 min or more and 30 g / 10 min or less, and even more preferably 25 g / 10 min or more and 28 g / 10 min or less.

[0051] (11) Haze (Transparency) of Resin Composition The haze of the resin composition according to JIS K 7136 is preferably 5% to 40%, more preferably 8% to 35%, and even more preferably 10% to 30%. The test piece of the resin composition used to measure the haze is a small square plate type D (60 mm x 60 mm x 2 mm thick) as specified in JIS K 7139:2009. The haze is measured using a test device (manufactured by Nippon Denshoku Industries Co., Ltd., product name: NDH8000). The haze is measured, for example, on a resin composition that does not contain inorganic pigments or black colorants.

[0052] 1-2.Method for producing resin composition The resin composition of the first embodiment is produced, for example, by melt-kneading a mixture of the above components. Alternatively, the resin composition may be produced, for example, by dissolving the above components in a solvent. The melt-kneading means is not particularly limited, and examples thereof include a twin-screw extruder, a Henschel mixer, a Banbury mixer, a single-screw extruder, a multi-screw extruder, and a co-kneader.

[0053] 1-3. Molded body The resin composition of the first embodiment can be used as a molding material for various molded articles. The resin composition of the first embodiment can be formed into a molded article having excellent low-temperature impact resistance, and is therefore suitable for, for example, vehicle decorative parts (automobile interior and exterior components, etc.). Examples of automobile interior components include pillars, instrument panels, door trims, and console boxes. Examples of automobile exterior components include spoilers, bumpers, fenders, door panels, and trunk lids. The resin composition of the first embodiment can also be used for the exterior of home appliances, etc.

[0054] Examples of methods for molding the resin composition into a molded article include injection molding, extrusion molding, blow molding, heat press molding, calendar molding, coating molding, cast molding, vacuum molding, and transfer molding.

[0055] 1-4. Physical properties of molded products (1) Tensile test The tensile strength, breaking strain, and elastic modulus of the molded product in a tensile test (JIS K 7161) are preferably within the following ranges: The tensile test is performed using a dumbbell-shaped tensile test piece type A1 specified in JIS K 7139:2009.

[0056] (1-1) Tensile strength The tensile strength of the molded article based on a tensile test is preferably 10.0 MPa or more, more preferably 15.0 MPa or more, and even more preferably 20.0 MPa or more. The upper limit of the tensile strength is not particularly limited, and is, for example, 50.0 MPa or less.

[0057] (1-2) Fracture strain The fracture strain of the molded article based on a tensile test is preferably 50% or more, more preferably 100% or more, and even more preferably greater than 150%. The upper limit of the fracture strain is not particularly limited, and is, for example, 1000% or less.

[0058] (1-3) Elastic modulus The elastic modulus of the molded article based on a tensile test is preferably 800 MPa or more, more preferably 850 MPa or more, and even more preferably 900 MPa or more. The upper limit of the elastic modulus is not particularly limited, and is, for example, 2500 MPa or less.

[0059] (2) Heat deflection temperature (HDT) The deflection temperature under load of the molded article (based on JIS K 7191) is preferably 50° C. or higher, preferably 60° C. or higher, and more preferably 70° C. or higher. There are no particular limitations on the upper limit of the deflection temperature under load, and it is, for example, 150° C. Here, the deflection temperature under load is measured by cutting a test piece (length 80 mm, width 10 mm, thickness 4 mm) from the molded article and using a heat destation tester under the condition of applying a bending stress of 0.45 MPa to the test piece.

[0060] (3) Charpy impact strength The Charpy impact strength of the molded product at 23°C (JIS K 7111 standard) is 5.0 kJ / m 2 More than 5.5kJ / m is preferable.2 More preferably, 6.0 kJ / m or more 2 The upper limit of the Charpy impact strength is not particularly limited, and is, for example, 10.0 kJ / m 2 The Charpy impact strength is measured using a Charpy impact tester (IT manufactured by Toyo Seiki Seisakusho Co., Ltd.).

[0061] The Charpy impact strength of the molded product at -30°C (JIS K 7111 standard) is 0.5kJ / m 2 More than 0.8kJ / m is preferable. 2 More preferably, 1.0 kJ / m or more 2 The upper limit of the Charpy impact strength is not particularly limited, and is, for example, 5.0 kJ / m 2 is.

[0062] (4) Lightness (L* value) The lightness (L* value) of the molded article in the L*a*b* color system according to JIS Z 8781-4 is preferably 0.5 to 2.5, more preferably 0.8 to 2.3, and even more preferably 1.0 to 2.0. The lightness (L* value) is measured using an L*a*b* colorimeter (manufactured by Nippon Denshoku Industries Co., Ltd., product name: SD7000) using a D65 light source as the observation light source, a viewing angle of 10°, and the specular exclusion method (SCE). The lightness (L* value) is measured, for example, on a molded article containing an inorganic pigment and / or a black colorant.

[0063] 1-5. Effects of the First Embodiment The resin composition and molded article of the first embodiment have improved transparency and excellent impact resistance. It is generally known that the inclusion of an ethylene-α-olefin copolymer in a resin composition reduces transparency. However, the resin composition of the first embodiment contains polypropylene and a propylene-α-olefin copolymer, thereby increasing transparency and improving impact resistance. The resin composition and molded article of the first embodiment can be widely used as vehicle decorative parts (automobile interior parts and automobile exterior parts). The resin composition and molded article of the first embodiment contain an inorganic pigment and / or a black colorant, which eliminates the need for painting, makes them easy to recycle, and is environmentally friendly from the viewpoint of carbon neutrality. In the resin composition and molded body of the first embodiment, when an inorganic pigment and / or a black colorant is contained, the effect of keeping the brightness (L value) low due to these coloring materials and the effect of suppressing light scattering due to the high transparency of the resin (low haze value) combine to enhance the jet black appearance. [Example]

[0064] The present invention will be explained in more detail below with reference to examples. 1. Preparation of resin composition and molded body Resin compositions and molded articles of Examples and Comparative Examples were prepared using the blending ratios shown in Tables 1 to 3. Details of the raw materials for the resin compositions in Tables 1 to 3 are shown in Table 4. Comparative Examples 1 to 3 employ the constitution of a conventionally known resin composition.

[0065] In Tables 1 to 3, the blending ratios represent blending ratios (parts by mass) when the total of the resin raw materials (polypropylene, ethylene-α-olefin copolymer, and propylene-α-olefin copolymer) is 100 parts by mass.

[0066] In Tables 1 to 3, "random polypropylene" is metallocene PP polymerized with a metallocene catalyst and has a melt flow rate (JIS K7210 standard, 230°C, 2.16 kg) of 30 g / 10 min. "Block polypropylene" is block polypropylene with a melt flow rate (JIS K7210 standard, 230°C, 2.16 kg) of 40 g / 10 min.

[0067] In the formulation of Table 1, the "ethylene-α-olefin copolymer" is LLDPE with a carbon number of 4. The density of the "ethylene-α-olefin copolymer" is 922 kg / m 3The melting point of the "ethylene-α-olefin copolymer" is 120°C. In Table 1, the MFR of the "ethylene-α-olefin copolymer" was measured under the condition of 190°C.

[0068] In the formulations in Tables 1 to 3, "propylene-α-olefin copolymer" is a propylene-ethylene-1-butene copolymer. The density of the "propylene-α-olefin copolymer" is 866 kg / m 3 In the "propylene-α-olefin copolymer", the content of structural units derived from propylene is 75 mol%, the content of structural units derived from ethylene is 7 mol%, and the content of structural units derived from 1-butene is 18 mol%. Here, the total of all structural units in the propylene-α-olefin copolymer is taken as 100 mol%. The melting point of the "propylene-α-olefin copolymer" is 160°C.

[0069] In the formulations of Tables 1 to 3, the "phenolic antioxidant" includes pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], the "phosphorus antioxidant" includes tris(2-ethylhexyl)phosphite, and the "weather resistance agent" includes a NOR-type hindered amine compound.

[0070] In Tables 1 to 3, the average particle size of "jet black carbon black" is 8 nm. In Tables 1 to 3, the "MFR of resin composition" is the MFR of the entire resin composition (e.g., for Comparative Examples 1 to 3 and Examples 1 and 2, a mixture of the above resin raw materials, jet black carbon black, zinc stearate, a phenolic antioxidant, a phosphorus-based antioxidant, and a weathering agent).

[0071] [Table 1]

[0072] [Table 2]

[0073] [Table 3]

[0074] [Table 4]

[0075] 1-2. Preparation of resin compositions and molded articles in examples and comparative examples Raw materials (for example, in Comparative Examples 1-3 and Examples 1 and 2, the above resin raw materials, jet black carbon black, zinc stearate, phenolic antioxidant, phosphorus-based antioxidant, and weathering agent) were mixed and melt-kneaded using a twin-screw extruder at a discharge rate of 30 kg / h, a rotation speed of 400 rpm, and 180°C to obtain a pellet-shaped resin composition. The obtained resin composition was injection-molded at 200°C to obtain a molded product.

[0076] 2. Evaluation Method 2-1. Melt flow rate of resin composition The melt flow rate of the resin composition was measured in accordance with JIS K 7210 at a heating temperature of 230° C. and a load of 2.16 kg.

[0077] 2-2. Haze The haze of the resin composition was measured in accordance with JIS K 7136. The test specimens of the resin composition used for haze measurement were small square plates type D (60 mm × 60 mm × 2 mm thick) as specified in JIS K 7139:2009. The haze was measured using a testing device (manufactured by Nippon Denshoku Industries Co., Ltd., product name: NDH8000). The haze measurement was performed on resin compositions that did not contain jet-black carbon black (for example, in Comparative Examples 1-3 and Examples 1 and 2, the compositions contained the above-mentioned resin raw materials, zinc stearate, a phenolic antioxidant, a phosphorus-based antioxidant, and a weathering agent; for example, in Example 5, the composition contained the above-mentioned resin raw materials, clarifying agent 1, a phenolic antioxidant, a phosphorus-based antioxidant, and a weathering agent).

[0078] 2-3.Tensile test The tensile test of the molded body was carried out based on JIS K 7161 to measure the tensile strength, breaking strain, and elastic modulus. The tensile test was carried out using a dumbbell-shaped tensile test piece type A1 specified in JIS K 7139:2009.

[0079] 2-3-1.Tensile strength The tensile strength of the molded body was measured in accordance with JIS K 7161 by a tensile test.

[0080] 2-3-2.Fracture strain The fracture strain of the molded body was measured in accordance with JIS K 7161 in a tensile test.

[0081] 2-3-3. Elastic modulus The elastic modulus of the molded body was measured in accordance with JIS K 7161 based on a tensile test.

[0082] 2-4. Heat deflection temperature (HDT) The deflection temperature under load of the molded body was measured in accordance with JIS K 7191. The deflection temperature under load was measured by cutting a test piece (length 80 mm, width 10 mm, thickness 4 mm) from the molded body and using a heat destation tester under the conditions of a bending stress of 0.45 MPa applied to the test piece and a standard deflection of 0.34 mm.

[0083] 2-5. Charpy impact strength The Charpy impact strength of the molded body at 23° C. and −30° C. was measured in accordance with JIS K 7111. The Charpy impact strength was measured using a Charpy impact tester (IT manufactured by Toyo Seiki Seisaku-sho, Ltd.).

[0084] 2-6. Lightness (L* value) The lightness (L* value) based on the L*a*b* color system of the molded articles in Comparative Examples 1-3 and Examples 1 and 2 was measured in accordance with JIS Z 8781-4. The lightness (L* value) was measured using an L*a*b* colorimeter (manufactured by Nippon Denshoku Industries Co., Ltd., product name: SD7000) with a D65 light source and a viewing angle of 10° using the specular exclusion (SCE) method. The lightness (L* value) was measured for a resin composition containing jet-black carbon black (a composition containing the above resin raw material, jet-black carbon black, zinc stearate, a phenolic antioxidant, a phosphorus-based antioxidant, and a weathering agent).

[0085] 3.Results The evaluation results are shown in Tables 1 to 3. Comparative Example 1 contains only random polypropylene as a resin raw material, while Comparative Example 2 contains block polypropylene in addition to random polypropylene as a resin raw material. Therefore, the molded body of Comparative Example 2 has a higher Charpy impact strength at 23°C, a higher lightness (L* value), and a higher haze (more cloudiness) than Comparative Example 1.

[0086] Comparative Example 3 contains an ethylene-α-olefin copolymer in addition to random polypropylene and block polypropylene as resin raw materials, and therefore has a larger haze (stronger cloudiness) than Comparative Examples 1 and 2.

[0087] Example 1 contains a propylene-α-olefin copolymer in addition to random polypropylene as a resin raw material. Therefore, the molded body of Example 1 has a higher Charpy impact strength at 23°C than Comparative Examples 1-3, and the lightness (L* value) and haze are comparable to those of Comparative Example 1. Thus, Example 1 has improved impact resistance while increasing transparency.

[0088] Example 2 contains a propylene-α-olefin copolymer in addition to random polypropylene and block polypropylene as resin raw materials. Therefore, the molded body of Example 2 has a higher Charpy impact strength at 23°C than Comparative Examples 1-3 and Example 1, and the lightness (L* value) and haze are lower than Comparative Examples 2 and 3. Thus, Example 2 achieves a good balance between improved transparency and improved impact resistance.

[0089] In Examples 3 and 4, similar to Example 2, the resin raw materials contain propylene-α-olefin copolymer in addition to random polypropylene and block polypropylene, but do not contain jet black carbon black or zinc stearate. The haze of the resin compositions of Examples 3 and 4 is similar to that of Example 2, and the transparency is high.

[0090] In Examples 5 and 6, compared to Example 4, the resin raw materials further contain Clarifying Agents 1 and 2, respectively. The haze of the resin compositions of Examples 5 and 6 is smaller than that of Example 4, and the transparency of the resin is further improved.

[0091] Examples 7-10 further contain mica, alumina, aluminum, and silica as resin raw materials compared to Example 4. The Charpy impact strength values ​​at 23°C of the molded bodies of Examples 7-10 are similar to those of Example 4, and impact resistance is improved.

[0092] 4. Effects of the Example According to the above examples, the polypropylene-based resin composition was able to improve the impact resistance while increasing the transparency.

[0093] The present disclosure is not limited to the above-described embodiments, and various modifications and variations are possible.

Claims

1. Polypropylene and a propylene-α-olefin copolymer; A resin composition comprising:

2. The resin composition according to claim 1 , further comprising an inorganic pigment and / or a black colorant.

3. The resin composition according to claim 2 , wherein the black colorant comprises carbon black and / or an organic dye.

4. The resin composition of claim 1 , further comprising a resin clarifying agent.

5. The resin composition according to claim 1, wherein the haze at a thickness of 2 mm according to JIS K 7136:2000 is 40% or less.

6. A molded article of the resin composition according to any one of claims 1 to 5.

7. L* value based on JIS Z 8781-4:2013 is 2.5 or less, and / or Charpy impact strength based on JIS K 7111 at 23 ° C is 5.0 kJ / m ２ The molded article according to claim 6, wherein the molded article is a molded article having the above structure.

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