Propylene resin composition

Abstract

To provide a propylene-based resin composition excellent in moldability (high fluidity), dimensional stability (low linear expansion coefficient), and balance of physical properties (high rigidity and high impact strength) and capable of obtaining high surface smoothness.SOLUTION: The propylene-based resin composition contains 30-90 wt.% of a polypropylene-based resin (A) satisfying specific conditions, 5-30 wt.% of a thermoplastic elastomer (B), and 5-40 wt.% of an inorganic filler (C) (provided that the total amount of the polypropylene-based resin (A), the thermoplastic elastomer (B), and the inorganic filler (C) is 100 wt.%).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a propylene-based resin composition and a molded article using the same, and more particularly to a propylene-based resin composition and a molded article that are excellent in moldability (high fluidity), dimensional stability (low linear expansion coefficient), and physical property balance (high rigidity, high impact strength), and that can obtain high surface smoothness.

Background Art

[0002] Propylene-based resin compositions have been widely used as various molded articles in the industrial parts field, such as automotive parts such as door trims, instrument panels, bumpers, side moldings, back doors, and fenders, and parts of home appliance products such as televisions, taking advantage of their excellent moldability, mechanical strength, environmental adaptability, and economy. On the other hand, since polypropylene has high crystallinity, it is known that the dimensional change (linear expansion coefficient) with respect to temperature is large. Due to this property, in automotive parts using propylene-based resin compositions, problems such as gaps occurring at the joints of parts and deterioration of the buildability during part assembly have arisen. In particular, molded articles such as automotive exterior members are becoming increasingly larger and more complex in design. Along with this, propylene-based resin compositions and their molded articles are required to simultaneously satisfy high physical property balance (high rigidity, impact strength), high dimensional stability, high moldability (high fluidity), and improvement of surface smoothness that further enhances the product value.

[0003] In addition to improving moldability (high fluidity), dimensional stability (low linear expansion coefficient), and physical property balance (high rigidity, high impact strength), a propylene-based resin composition containing a specific propylene-based polymer, a specific ethylene-α-olefin copolymer, and a specific talc in specific amounts, respectively, has been proposed for the purpose of obtaining a polypropylene-based resin composition and an automotive exterior member with good painted appearance quality (see, for example, Patent Document 1). However, the smoothness of the product surface of this resin composition was not sufficient.

[0004] Furthermore, polypropylene resin compositions for automotive exterior components have been proposed that contain specific amounts of a specific propylene-α-olefin block copolymer, a specific ethylene-butene copolymer, and talc of a specific shape, in order to improve dimensional stability (low coefficient of thermal expansion), moldability (high fluidity), and balance of physical properties (high rigidity, high impact strength), as well as to improve flow marks and weld appearance (see, for example, Patent Document 2). However, the patent document did not describe the smoothness of the product surface, and the dimensional stability (low coefficient of thermal expansion) of the resin composition was not sufficient.

[0005] Furthermore, in order to improve dimensional stability (low coefficient of thermal expansion), balance of mechanical properties (high rigidity, high impact strength), and reduce the protrusion of butt welds, low-linear-expansion polypropylene resin compositions containing specific amounts of specific propylene-α-olefin block copolymers, specific ethylene-butene copolymers, and talc of a specific shape have been proposed (see, for example, Patent Document 3). However, the examples in the patent document in question focused on the appearance performance (weld ridges) at the butt weld area and were not sufficient to satisfy the overall surface smoothness requirements of the molded body.

[0006] Under these circumstances, there was a need for a propylene-based resin composition that would overcome the problems of conventional propylene-based resin compositions and possess the necessary properties for obtaining automotive exterior parts such as bumpers, side moldings, tailgates, and fenders: high moldability (high fluidity), dimensional stability (low coefficient of thermal expansion), and a high balance of physical properties (high rigidity, high impact strength), as well as excellent surface smoothness of the product. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] No. 5827143 Patent Publication [Patent Document 2] No. 6006058 Patent Publication [Patent Document 3] No. 6560612 Patent Publication [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The object of the present invention is to provide a propylene-based resin composition and molded article that, in view of the problems of the prior art described above, is excellent in moldability (high fluidity), dimensional stability (low coefficient of thermal expansion), and balance of physical properties (high rigidity, high impact strength), as well as high surface smoothness. [Means for solving the problem]

[0009] To solve the above problems, the inventors conducted extensive research and, as a result, discovered that a propylene-based resin composition containing specific amounts of a particular polypropylene-based resin (A), a thermoplastic elastomer (B), and an inorganic filler (C) exhibits excellent moldability (high fluidity), dimensional stability (low coefficient of thermal expansion), and balance of physical properties (high rigidity, high impact strength), as well as high surface smoothness, thus completing the present invention.

[0010] In other words, according to the first invention of the present invention, 5 to 95% by weight of a propylene-ethylene block copolymer (A1) satisfying the following characteristic (A1-1), 5-95% by weight of a propylene-ethylene block copolymer (A2) that satisfies the following characteristic (A2-1). (The total amount of the propylene-ethylene block copolymer (A1) and the propylene-ethylene block copolymer (A2) is 100% by weight) and contains A polypropylene resin (A) that satisfies the following characteristic (A-1), Thermoplastic elastomer (B) and It contains an inorganic filler (C), A propylene-based resin composition is provided that satisfies the following condition (a). Characteristics (A1-1): Propylene-ethylene block copolymer (A1) is It contains a propylene polymer portion (a11) and an ethylene-propylene random copolymer portion (a12), The intrinsic viscosity [η] of the ethylene-propylene random copolymer portion (a12), measured at 135°C in decalin solution, is 1.5–4.5 dl / g. Characteristics (A2-1): The propylene-ethylene block copolymer (A2) contains a propylene polymer portion (a21) and an ethylene-propylene random copolymer portion (a22). The intrinsic viscosity [η] of the ethylene-propylene random copolymer portion (a22), measured at 135°C in decalin solution, is 5.0–9.5 dl / g. Characteristics (A-1): Polypropylene resin (A) has an overall melt flow rate (230°C, 2.16 kg load) of 10-200 g / 10 min. Condition (a): The propylene resin composition comprises 30-90% by weight of polypropylene resin (A), 5-30% by weight of thermoplastic elastomer (B), and 5-40% by weight of inorganic filler (C) (provided that the total amount of polypropylene resin (A), thermoplastic elastomer (B), and inorganic filler (C) is 100% by weight).

[0011] Furthermore, according to the second invention of the present invention, a propylene-based resin composition is provided characterized in that, in the first invention, the propylene-ethylene block copolymer (A1) further satisfies the following properties (A1-2) to (A1-5). Characteristics (A1-2): The melt flow rate of the propylene polymer portion (a11) (230°C, 2.16 kg load) is 100 g / 10 min or more. Characteristics (A1-3): The proportion of the ethylene-propylene random copolymer portion (a12) to the total propylene-ethylene block copolymer (A1) is 10-30% by weight. Characteristics (A1-4): The melt flow rate (at 230°C and a load of 2.16 kg) of the entire propylene-ethylene block copolymer (A1) is 20 to 150 g / 10 min. Characteristic (A1-5): The ethylene content of the ethylene-propylene random copolymer portion (a12) is 30 to 50% by weight.

[0012] Further, according to the third invention of the present invention, in the first invention, there is provided a propylene-based resin composition characterized in that the propylene-ethylene block copolymer (A2) further satisfies the following characteristics (A2-2) to (A2-5). Characteristic (A2-2): The melt flow rate (at 230°C and a load of 2.16 kg) of the propylene polymer portion (a21) is 250 g / 10 min or more. Characteristic (A2-3): The ratio of the ethylene-propylene random copolymer portion (a22) to the entire propylene-ethylene block copolymer (A2) is 5 to 25% by weight. Characteristic (A2-4): The melt flow rate (at 230°C and a load of 2.16 kg) of the entire propylene-based copolymer (A2) is 20 to 120 g / 10 min. Characteristic (A2-5): The ethylene content of the ethylene-propylene random copolymer portion (a22) is 30 to 50% by weight.

[0013] Further, according to the fourth invention of the present invention, in the first invention, there is provided a propylene-based resin composition characterized in that the inorganic filler (C) is talc having an average particle diameter exceeding 8.5 μm and an aspect ratio exceeding 10.

[0014] Further, according to the fifth invention of the present invention, there is provided a molded article obtained by molding the propylene-based resin composition of any one of the first to fourth inventions.

Advantages of the Invention

[0015] According to the present invention, a propylene-based resin composition can be obtained that possesses the necessary properties for obtaining automotive parts such as bumpers, side moldings, tailgates, and fenders, including high moldability (high fluidity), dimensional stability (low coefficient of thermal expansion), and a balance of physical properties (high rigidity, high impact strength), as well as excellent surface smoothness of the product. [Modes for carrying out the invention]

[0016] The present invention relates to a propylene resin composition containing specific amounts of a specific polypropylene resin (A), a thermoplastic elastomer (B), and an inorganic filler (C), and a molded article made using the same. The following provides a detailed explanation of the constituent components of the propylene-based resin composition, the resin composition itself, its manufacturing and molding processes, and related materials.

[0017] [I] Components of propylene resin composition 1. Polypropylene resin (A) The polypropylene resin (A) (hereinafter also simply referred to as component A) used in the propylene resin composition of the present invention has an overall melt flow rate (hereinafter also referred to as MFR) (230°C, 2.16 kg load) of 10 to 200 g / 10 min, preferably in the range of 20 to 150 g / 10 min, and more preferably in the range of 30 to 120 g / 10 min.

[0018] Component A has characteristics that contribute to maintaining and improving the balance of physical properties such as fluidity (moldability) and rigidity / impact strength in the propylene-based resin composition of the present invention. If the total MFR of component A is 10 g / 10 min or more, the fluidity (moldability) of the resin composition of the present invention and the molded article made therefrom (hereinafter also simply referred to as the molded article) can be improved. On the other hand, if the total MFR of component A is 200 g / 10 min or less, the balance of physical properties (impact strength) can be improved. The MFR value is measured in accordance with JIS K7210, at a measurement temperature of 230°C and a load of 2.16 kg.

[0019] Component A contains 5 to 95% by mass of a propylene-ethylene block copolymer (A1) (hereinafter also simply referred to as component A1) containing an ethylene-propylene random copolymer portion with an intrinsic viscosity [η] of 1.5 to 4.5 dl / g, and 5 to 95% by mass of a propylene-ethylene block copolymer (A2) (hereinafter also simply referred to as component A2) containing an ethylene-propylene random copolymer portion with an intrinsic viscosity [η] of 5.0 to 9.5 dl / g (the sum of component A1 and component A2 is 100% by mass). Here, the intrinsic viscosity [η] is a value obtained by measuring it at a temperature of 135°C using an Ubbelohde viscometer with decalin as the solvent.

[0020] The ratio of component A1 to component A2 in component A (the sum of component A1 and component A2 is 100% by mass) is preferably 5-95% by weight for component A1 and 5-95% by weight for component A2, preferably 10-85% by weight for component A1 and 15-90% by weight for component A2, more preferably 20-80% by weight for component A1 and 20-80% by weight for component A2, and even more preferably 35-65% by weight for component A1 and 35-65% by weight for component A2. When the content of component A1 is 5% by weight or more (i.e., the content of component A2 is 95% by weight or less), the dimensional stability (low coefficient of thermal expansion) of the resin composition of the present invention and molded articles made therefrom can be improved. On the other hand, when the content of component A1 is 95% by weight or less (i.e., the content of component A2 is 5% by weight or more), the surface smoothness can be improved.

[0021] 2. Propylene-ethylene block copolymer (A1) The propylene-ethylene block copolymer (A1) (component A1) used in the propylene-based resin composition of the present invention satisfies the following property (A1-1). Characteristics (A1-1): The propylene-ethylene block copolymer (A1) contains a propylene polymer portion (a11) and an ethylene-propylene random copolymer portion (a12), and the intrinsic viscosity [η] (measured at 135°C in decalin solution) of the ethylene-propylene random copolymer portion (a12) is preferably in the range of 1.5 to 4.5 dl / g, more preferably 2.0 to 4.0 dl / g, and more preferably 2.5 to 3.6 dl / g. An intrinsic viscosity [η] of 1.5 dl / g or higher improves surface smoothness, while an intrinsic viscosity [η] of 4.5 dl / g or lower improves fluidity (moldability) and dimensional stability (low coefficient of thermal expansion). Note that two or more components A1 may be used in combination, and in that case, the intrinsic viscosity [η] is naturally the value of the entire component A1 after combination.

[0022] In order to further enhance the effects of the present invention, it is desirable that component A1 also satisfies the following characteristics (A1-2) to (A1-5). Characteristics (A1-2): The melt flow rate of the propylene polymer portion (a11) (230°C, 2.16 kg load) is 100 g / 10 min or more. Characteristics (A1-3): The proportion of the ethylene-propylene random copolymer portion (a12) to the total propylene-ethylene block copolymer (A1) is 10-30% by weight. Characteristics (A1-4): The total melt flow rate of the propylene-ethylene block copolymer (A1) (230°C, 2.16 kg load) is 20-150 g / 10 min. Characteristics (A1-5): The ethylene content of the ethylene-propylene random copolymer portion (a12) is 30-50% by weight.

[0023] 2-1. Characteristics of Component A1 (1) Characteristics (A1-2): The MFR (at 230°C and 2.16 kg load) of the propylene polymer portion (a11) in component A1 used in the propylene-based resin composition of the present invention is 100 g / 10 min or more, preferably 120 to 400 g / 10 min, and more preferably 130 to 300 g / 10 min. An MFR of 100 g / 10 min or more suppresses the occurrence of flow marks (deterioration of molded appearance) in the resin composition and molded article, and improves fluidity (moldability). This MFR is the MFR at the time when polymerization of the propylene polymer portion is completed, and in the case of multi-stage polymerization of the propylene polymer portion, it is the MFR of the propylene polymer portion removed from the final polymerization tank.

[0024] (2) Characteristics (A1-3): The proportion of the ethylene-propylene random copolymer portion (a12) in component A1 to the total propylene-ethylene block copolymer (A1) is 10 to 30% by weight, preferably 12 to 28% by weight, and more preferably 14 to 26% by weight. In other words, the proportion of the propylene polymer portion (a11) to the total component A1 is 70-90% by weight, preferably 72-88% by weight, and more preferably 74-86% by weight. When the ethylene-propylene random copolymer portion (a12) is 10% by weight or more (i.e., the propylene polymer portion (a11) is 90% by weight or less), the balance of physical properties (impact strength) of the resin composition and molded article of the present invention can be improved. On the other hand, when the proportion of the ethylene-propylene random copolymer portion (a12) is 30% by weight or less (i.e., the propylene polymer portion (a11) is 70% by weight or more), the occurrence of flow marks (deterioration of molded appearance) can be suppressed, and the balance of physical properties (rigidity) can be improved.

[0025] (3) Characteristics (A1-4): The total MFR (at 230°C and a 2.16 kg load) of component A1 is 20 to 150 g / 10 min, preferably 25 to 130 g / 10 min, and more preferably 30 to 110 g / 10 min. When the MFR is 20 g / 10 min or higher, the occurrence of flow marks (deterioration of molded appearance) in the propylene-based resin composition and molded articles of the present invention can be suppressed, and the fluidity (moldability) and balance of physical properties can be improved. On the other hand, when the MFR is 150 g / 10 min or lower, the balance of physical properties (impact strength) can be improved.

[0026] (4) Characteristics (A1-5): The ethylene content of the ethylene-propylene random copolymer portion (a12) in component A1 is 30 to 50% by weight, preferably 35 to 45% by weight. When the ethylene content is within the above range, the scratch resistance and physical property balance of the propylene-based resin composition and molded article of the present invention can be improved.

[0027] 3. Propylene-ethylene block copolymer (A2) The propylene-ethylene block copolymer (A2) (component A2) used in the propylene-based resin composition of the present invention satisfies the following characteristic (A2-1). Characteristics (A2-1): The propylene-ethylene block copolymer (A2) contains a propylene polymer portion (a21) and an ethylene-propylene random copolymer portion (a22), and the intrinsic viscosity [η] (measured at 135°C in decalin solution) of the ethylene-propylene random copolymer portion (a22) is preferably in the range of 5.0 to 9.5 dl / g, more preferably 6.0 to 9.0 dl / g, and more preferably 7.0 to 8.5 dl / g. An intrinsic viscosity [η] of 5.0 dl / g or higher improves surface smoothness, while an intrinsic viscosity [η] of 9.5 dl / g or lower suppresses poor surface appearance due to the formation of aggregates called gels and improves dimensional stability (low coefficient of thermal expansion). Note that two or more types of component A2 may be used in combination, and in that case, the intrinsic viscosity [η] is naturally the value of the entire component A2 after combination.

[0028] In order to further enhance the effects of the present invention, it is desirable that component A2 also satisfies the following characteristics (A2-2) to (A2-5). Characteristics (A2-2): The melt flow rate of the propylene polymer portion (a21) (230°C, 2.16 kg load) is 250 g / 10 min or more. Characteristics (A2-3): The proportion of the ethylene-propylene random copolymer portion (a22) to the total propylene-ethylene block copolymer (A2) is 5-25% by weight. Characteristics (A2-4): The total melt flow rate of the propylene-ethylene block copolymer (A2) (230°C, 2.16 kg load) is 20-120 g / 10 min. Characteristics (A2-5): The ethylene content of the ethylene-propylene random copolymer portion (a22) is 30-50% by weight.

[0029] 3-1. Characteristics of Component A2 (1) Characteristics (A2-2): The MFR (at 230°C and 2.16 kg load) of the propylene polymer portion (a21) in component A2 used in the propylene resin composition of the present invention is 250 g / 10 min or more, preferably 300 to 500 g / 10 min, and more preferably 350 to 450 g / 10 min. An MFR of 250 g / 10 min or more suppresses the occurrence of flow marks (deterioration of molded appearance) in the propylene resin composition and molded article, and improves fluidity (moldability). This MFR is the MFR at the time when polymerization of the propylene polymer portion is completed, and in the case of multi-stage polymerization of the propylene polymer portion, it is the MFR of the propylene polymer portion removed from the final polymerization tank.

[0030] (2) Characteristics (A2-3): The proportion of the ethylene-propylene random copolymer portion (a22) in component A2 to the total propylene-ethylene block copolymer (A2) is 5 to 25% by weight, preferably 7 to 23% by weight, and more preferably 9 to 20% by weight. In other words, the proportion of the propylene polymer portion (a21) to the total component A2 is 75-95% by weight, preferably 77-93% by weight, and more preferably 80-91% by weight. When the ethylene-propylene random copolymer portion (a22) is 5% by weight or more (i.e., the propylene polymer portion (a21) is 95% by weight or less), the balance of physical properties (impact strength) of the propylene-based resin composition and molded article of the present invention can be improved. On the other hand, when the proportion of the ethylene-propylene random copolymer portion (a22) is 25% by weight or less (i.e., the propylene polymer portion (a21) is 75% by weight or more), the occurrence of flow marks (deterioration of molded appearance) can be suppressed, and the balance of physical properties (rigidity) can be improved.

[0031] (3) Characteristics (A2-4): The total MFR (Mold Free Load) of component A2 (at 230°C, 2.16 kg load) is 20 to 120 g / 10 min, preferably 25 to 110 g / 10 min, and more preferably 30 to 100 g / 10 min. When the MFR is 20 g / 10 min or higher, the occurrence of flow marks (deterioration of molded appearance) in the propylene-based resin composition and molded article of the present invention can be suppressed, and the fluidity (moldability) and balance of physical properties can be improved. On the other hand, when the MFR is 120 g / 10 min or lower, the balance of physical properties (impact strength) can be improved.

[0032] (4) Characteristics (A2-5): The ethylene content of the ethylene-propylene random copolymer portion (a22) in component A2 is 30 to 50% by weight, preferably 35 to 45% by weight. When the ethylene content is within the above range, the scratch resistance and physical property balance of the propylene-based resin composition and molded article of the present invention can be improved.

[0033] Production of propylene ethylene block copolymer The method for producing propylene-ethylene block copolymer is not particularly limited and can be appropriately selected from known methods and conditions. As a polymerization catalyst for propylene, a highly stereoregular catalyst is usually used. Examples include catalysts obtained by reducing titanium tetrachloride with an organoaluminum compound and further treating it with various electron donors and electron acceptors to obtain a titanium trichloride composition, and a combination of an organoaluminum compound and an aromatic carboxylic acid ester (see, for example, Japanese Patent Publication Nos. 56-100806, 56-120712, and 58-104907), and supported catalysts obtained by contacting magnesium halide with titanium tetrachloride and various electron donors (see, for example, Japanese Patent Publication Nos. 57-63310, 63-43915, and 63-83116), as described in various publications.

[0034] The copolymer is obtained by polymerizing propylene in the presence of the catalyst, using a manufacturing process such as gas-phase polymerization, liquid-phase bulk polymerization, or slurry polymerization, followed by random polymerization of propylene and ethylene. To obtain the propylene-ethylene block copolymer having the aforementioned intrinsic viscosity [η], multi-stage polymerization using the slurry method or gas-phase fluidized bed method is preferable. The polymerization of the propylene polymer portion may be a single-step polymerization or a multi-step polymerization of propylene, but it is more preferable to obtain it by multi-step polymerization in order to exhibit the aforementioned properties. As an example of a multi-stage polymerization method for the propylene polymer portion, a two-stage polymerization method consisting of steps (1) and (2) shown below can be cited. Step (1): Propylene is polymerized in the presence of hydrogen as a molecular weight modifier. This is to suppress the formation of polymers with excessively large molecular weights. The hydrogen concentration is usually selected from a range of 0.1 mol% to 40 mol% relative to the total amount of monomer. Furthermore, the polymerization temperature is typically selected from 40°C to 90°C, and the pressure is typically selected from a range of 0.1 MPa to 5 MPa relative to atmospheric pressure. The amount of polymer obtained in step (1) is usually adjusted to be 70-95% by weight of the total polymerized material. If the amount of polymer produced in step (1) is 70% by weight or more, it is possible to prevent the amount of high molecular weight propylene polymer produced in step (2) from becoming too large, thereby improving fluidity (moldability).

[0035] The propylene polymer portion is preferably a propylene homopolymer in order to enhance the balance of physical properties (rigidity) of the resin composition of the present invention. However, for the purpose of further improving fluidity (moldability) and the balance of physical properties, it may also be a copolymer with a small amount of comonomer, as long as the crystallinity is not significantly impaired. Specifically, the material may contain, preferably in a content of 5% by weight or less, comonomer units corresponding to one or more comonomers selected from the group consisting of α-olefins other than propylene, such as ethylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, and 4-methyl-1-pentene, as well as vinyl compounds such as styrene, vinylcyclopentene, vinylcyclohexane, and vinylnorbornane. These comonomers may be copolymerized in two or more forms. The comonomers are preferably ethylene and / or 1-butene, with ethylene being the most preferred. Here, the content of the comonomer units is determined by infrared spectroscopy (IR).

[0036] Step (2): In order to polymerize a propylene polymer with a higher molecular weight compared to the propylene polymer portion produced in Step (1), it is preferable to polymerize under a hydrogen atmosphere with the lowest possible concentration or in a state where hydrogen is substantially absent. Polymerization is carried out in the presence of the propylene polymer produced in Step (1) and the catalyst. The polymerization temperature is typically selected from 40°C to 90°C, and the pressure is typically selected from a range of 0.1 MPa to 5 MPa relative to atmospheric pressure. The amount of polymer obtained in this step (2) is usually adjusted to be 5 to 30% by weight of the total polymerized amount. Furthermore, to suppress gel formation and stickiness, it is desirable to add alcohols such as ethanol during or before the reaction of the ethylene-propylene random copolymer portion. Specifically, the alcohol / organoaluminum compound ratio should be between 0.5 and 3.0 molars. The proportion of the ethylene-propylene random copolymer portion in the propylene-ethylene block copolymer can also be controlled by the amount of alcohol added. Any combination of steps (1) and (2) can be used as long as the physical properties of the resulting polymer can be adjusted to the aforementioned range.

[0037] The MFR of the propylene-ethylene block copolymer is measured using an MFR meter. The content of the ethylene-propylene random copolymer portion, the ethylene content, and the Q value are measured using a cross-fractionation apparatus, Fourier transform infrared absorption spectroscopy, and gel permeation chromatography (GPC). The intrinsic viscosity [η] is measured using an Ubbelohde viscometer. The measurement conditions for the main parameters are described in the examples.

[0038] 4. Thermoplastic elastomer (B) Component B (hereinafter also simply referred to as component B) of the thermoplastic elastomer used in the propylene-based resin composition of the present invention is an olefin-based elastomer and / or a styrene-based elastomer, and has characteristics that contribute to improving the balance of physical properties (such as impact strength) and dimensional stability in the resin composition and molded articles of the present invention.

[0039] The thermoplastic elastomer (B) used in the present invention is at least one elastomer selected from the group consisting of olefin-based elastomers and styrene-based elastomers, and is a polymer (elastomer) having rubber-like properties. In the present invention, the ethylene content in component B is preferably more than 50% by weight, more preferably 60% to 90% by weight, and the melt flow rate of component B (230°C, 2.16 kg load) is preferably 0.1 g / 10 min to 100 g / 10 min, more preferably 0.5 g / 10 min to 60 g / 10 min, and particularly preferably 1.0 g / 10 min to 30 g / 10 min. By setting the MFR within this range, it is possible to achieve a good balance of physical properties (such as impact strength) and dimensional stability in the propylene-based resin composition of the present invention. That is, if the melt flow rate of thermoplastic elastomer (B) is 0.1 g / 10 min or higher, dimensional stability and paint adhesion can be improved. Using a flow rate of 100g / 10min or less can suppress the occurrence of flow marks (deterioration of molded appearance) while also improving impact performance.

[0040] 4-1. Types Component B can be an olefin-based elastomer, and examples include ethylene-α-olefin copolymer elastomers such as ethylene-butene copolymer elastomer (EBR), ethylene-hexene copolymer elastomer (EHR), ethylene-octene copolymer elastomer (EOR), and ethylene-propylene copolymer elastomer (EPR); and ethylene-α-olefin-diene terpolymer elastomers such as ethylene-propylene-ethylidene norbornene copolymer, ethylene-propylene-butadiene copolymer, and ethylene-propylene-isoprene copolymer. Examples of styrene-based elastomers include styrene-butadiene-styrene triblock copolymer elastomer (SBS), styrene-isoprene-styrene triblock copolymer elastomer (SIS), styrene-ethylene-butylene copolymer elastomer (SEB), styrene-ethylene-propylene copolymer elastomer (SEP), styrene-ethylene-butylene-styrene copolymer elastomer (SEBS), styrene-ethylene-butylene-ethylene copolymer elastomer (SEBC), hydrogenated styrene-butadiene elastomer (HSBR), styrene-ethylene-propylene-styrene copolymer elastomer (SEPS), styrene-ethylene-ethylene-propylene-styrene copolymer elastomer (SEEPS), styrene-butadiene-butylene-styrene copolymer elastomer (SBBS), partially hydrogenated styrene-isoprene-styrene copolymer elastomer, and partially hydrogenated styrene-isoprene-butadiene-styrene copolymer elastomer. Furthermore, hydrogenated polymer elastomers such as ethylene-ethylene-butylene-ethylene copolymer elastomers (CEBC) can also be mentioned. In particular, the use of ethylene-octene copolymer elastomer (EOR) and / or ethylene-butene copolymer elastomer (EBR) is preferred because the resin composition and molded articles of the present invention tend to have superior physical property balance (such as impact strength), fluidity (moldability), and dimensional stability, as well as superior economic efficiency. Note that two or more types of component B may be used in combination.

[0041] 4-2.Manufacturing Component B, for example, olefin-based elastomers such as ethylene-α-olefin copolymer elastomers and ethylene-α-olefin-diene terpolymer elastomers, is produced by polymerizing each monomer in the presence of a catalyst. As catalysts, for example, titanium compounds such as titanium halides, organoaluminum-magnesium complexes such as alkylaluminum-magnesium complexes, so-called Ziegler-type catalysts such as alkylaluminum or alkylaluminum chloride, and metallocene compound catalysts described in pamphlet WO91 / 04257 can be used. Polymerization can be carried out using various manufacturing processes, including the gas-phase fluidized bed method, the solution method, and the slurry method. Furthermore, styrene-based elastomers can be manufactured by conventional anionic polymerization methods and their polymer hydrogenation techniques.

[0042] 4-3.Blending ratio The proportion of component B is 5 to 30 parts by mass, preferably 10 to 27 parts by mass, and more preferably 15 to 25 parts by mass, based on a total amount of 100 parts by mass of component A, component B, and inorganic filler (C). When the amount of component B is 30 parts by mass or less, it is possible to suppress the occurrence of flow marks (deterioration of molded appearance) and improve the balance of physical properties (rigidity) and fluidity (moldability). On the other hand, when the amount of component B is 5 parts by mass or more, it is possible to improve the balance of mechanical properties such as impact strength.

[0043] 5.Inorganic filler (C) The inorganic filler (C) (hereinafter also simply referred to as component C) used in the propylene resin composition of the present invention has characteristics that contribute to improving the balance of physical properties (such as rigidity), dimensional stability (such as reduction of the coefficient of linear expansion), and environmental adaptability of the propylene resin composition and molded article of the present invention.

[0044] 5-1. Types, shapes, etc. Specific examples of component C include, for example, inorganic fillers such as silica, diatomaceous earth, barium ferrite, beryllium oxide, pumice, pumice balloons and other oxides, aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate and other hydroxides, calcium carbonate, magnesium carbonate, dolomite, dawsonite and other carbonates, calcium sulfate, barium sulfate, ammonium sulfate, calcium sulfite and other sulfates or sulfites, talc, clay, mica, glass fibers, glass balloons, glass beads, calcium silicate, wollastonite, montmorillonite, bentonite and other silicates, carbon compounds such as carbon black, graphite, carbon fibers, and hollow carbon spheres, as well as molybdenum sulfide, boron fibers, zinc borate, barium metaborate, calcium borate, sodium borate, magnesium oxysulfate, basic magnesium sulfate fibers, potassium titanate fibers, aluminum borate fibers, calcium silicate fibers, calcium carbonate fibers, and various metal fibers. Note that two or more types of component C may be used in combination.

[0045] There are no particular restrictions on the shape of component C; any shape, such as granular, plate-like, fibrous, rod-like, or whisker-like, can be used. Among these, plate-shaped, fibrous, and whisker-shaped materials are preferred because they easily yield resin compositions and molded articles of the present invention that have excellent balance of physical properties and dimensional stability. In addition, any commercially available polymer fillers can be used. These are often manufactured in forms other than the common powder form, such as compressed solids, pellets (granules), granules, and chopped strands, which offer improved handling convenience, and all of these forms can be used. Among these, powder, compressed solids, and granules are preferred.

[0046] Of the aforementioned component C, at least one selected from talc, whiskers, and glass fibers is preferred because it makes it easier to obtain the resin composition and molded articles of the present invention that are excellent in terms of scratch resistance, balance of physical properties, and economy. Furthermore, the term "whiskers" here refers to extremely fine (generally 2 μmφ or less, especially 1 μmφ or less) fibrous materials such as basic magnesium sulfate fibers, potassium titanate fibers, aluminum borate fibers, calcium silicate fibers, calcium carbonate fibers, and ultrafine carbon fibers.

[0047] Among these, talc is preferred as component C, and talc with an average particle size exceeding 8.5 μm, preferably 9 to 15 μm, and especially preferably 9.5 to 12 μm, is preferred because it is easier to obtain the resin composition and molded articles of the present invention which have particularly excellent scratch resistance, balance of physical properties, and economic efficiency. This average particle size is a value measured using a laser diffraction scattering particle size analyzer, for example, the LA-920 model manufactured by Horiba, Ltd. Furthermore, talc with an aspect ratio exceeding 10, particularly 12 or higher, and more preferably 15 or higher, is preferred. The aspect ratio of talc is determined from values ​​measured using a microscope or the like.

[0048] These components C may be those whose surfaces have been treated with organic titanate coupling agents, organic silane coupling agents, unsaturated carboxylic acids, or modified polyolefins grafted with their anhydrides, fatty acids, fatty acid metal salts, fatty acid esters, etc., or two or more of these may be used in combination to treat the surfaces.

[0049] 5-2.Manufacturing The method for producing component C is not particularly limited and can be produced by various known manufacturing methods. For example, in the case of talc, it can be obtained by mechanically grinding naturally occurring talc into fine particles and then further classifying it precisely once or multiple times. Examples of crushing machines that can be used include jaw crushers, hammer crushers, roll crushers, screen mills, jet crushers, colloid mills, roller mills, and vibratory mills. These crushed talc particles are subjected to wet or dry classification, once or repeatedly, using equipment such as a cyclone, cyclone air separator, microseparator, cyclone air separator, or sharpcut separator, to adjust them to the average particle size shown in the present invention. It is preferable to perform the classification operation using a sharpcut separator after crushing to a specific particle size.

[0050] 5-3.Blending ratio The proportion of component C is 5 to 40 parts by mass, preferably 10 to 38 parts by mass, more preferably 15 to 34 parts by mass, and even more preferably 20 to 30 parts by mass, based on a total amount of component A, component B, and component C of 100 parts by mass. When the amount of component C is 5 parts by mass or more, the balance of physical properties (rigidity, heat resistance, etc.) of the resin composition and molded article of the present invention can be improved. Furthermore, when the amount of component C is 40 parts by mass or less, the occurrence of flow marks (deterioration of molded appearance) can be suppressed, and scratch resistance and fluidity (moldability) can be improved.

[0051] 6.Optional addition ingredients In the present invention, in addition to components A to C, optional additives may be included as needed, to the extent that they do not significantly impair the effects of the present invention, for example, to further improve the inventive effects or to impart other effects.

[0052] Specifically, examples include antioxidants such as phenol-based and phosphorus-based compounds, colorants, light stabilizers such as hindered amine-based compounds, ultraviolet absorbers such as benzotriazole-based compounds, nucleating agents such as sorbitol-based compounds, antistatic agents such as nonionic compounds, neutralizing agents such as inorganic compounds, antibacterial and antifungal agents such as thiazole-based compounds, flame retardants such as halogen compounds, plasticizers, dispersants such as organometallic salts, lubricants, metal deactivators such as nitrogen compounds, surfactants such as nonionic compounds, polyolefin resins such as polypropylene-based resins that do not fall under component A, thermoplastic resins such as polyamide resins and polyester resins, and elastomers (rubber components) that do not fall under component B. These optional additives may be used in combination of two or more types, added to the composition, or added to each of the aforementioned components A to C, and each component may also be used in combination of two or more types.

[0053] As coloring components, for example, inorganic and organic pigments are effective in imparting and improving scratch resistance, colored appearance, aesthetics, texture, commercial value, weather resistance, and durability of the resin composition and molded articles of the present invention. Specific examples of inorganic pigments include titanium dioxide; iron oxide (such as red iron oxide); chromic acid (such as yellow lead); molybdic acid; selenides sulfides; and ferrocyanides. Organic pigments include azo pigments such as sparingly soluble azo lakes; soluble azo lakes; insoluble azo chelates; and condensing azo chelates; phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; slene pigments such as anthraquinone, perinone, and perylene; dye lakes; quinacridone-based pigments; dioxazine-based pigments; and isoindolinone-based pigments.

[0054] For example, hindered amine compounds, benzotriazole compounds, benzophenone compounds, and salicylate compounds are effective as light stabilizers and ultraviolet absorbers in providing and improving the weather resistance and durability of the resin composition and molded articles of the present invention. Specific examples of hindered amine compounds include the condensate of dimethyl succinate and 1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine; poly[[6-(1,1,3,3-tetramethylbutyl)imino-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]]; tetrakis(2,2,6,6-tetramethyl-4-piperidyl)1,2,3,4-butanetetracarboxylate; tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)1,2,3,4-butanetetracarboxylate; bis(1,2,2,6,6-pentame Examples of benzotriazoles include 2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole and 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole. Examples of benzophenones include 2-hydroxy-4-methoxybenzophenone and 2-hydroxy-4-n-octoxybenzophenone. Examples of salicylates include 4-t-butylphenyl salicylate and 2,4-di-t-butylphenyl 3',5'-di-t-butyl-4'-hydroxybenzoate. In this case, the method of using the light stabilizer and the ultraviolet absorber in combination is preferable because it has a significant effect in improving weather resistance, durability, and other properties.

[0055] [II] Method for producing propylene resin compositions, method for producing molded articles, and uses The propylene resin composition of the present invention can be produced by compounding, mixing, and melt-kneading components A to C (and optional additives as needed) in the above-mentioned proportions using conventionally known methods. Mixing is typically carried out using mixing equipment such as tumblers, V-blenders, and ribbon blenders, while melt-kneading is typically performed using kneading equipment such as single-screw extruders, twin-screw extruders, Banbury mixers, roll mixers, Brabender plastographs, and kneaders, followed by granulation. Furthermore, when manufacturing by melt-mixing and granulation, the mixture of each component may be mixed simultaneously. In addition, to improve performance, each component may be mixed separately; for example, component A and component B (and any additional components as needed) may be mixed first, and then the remaining component C may be mixed and granulated.

[0056] The molded article of the present invention is a molded article obtained by molding the propylene-based resin composition of the present invention. The molded article of the present invention can be obtained by molding the polypropylene-based resin composition produced by the above method using, for example, well-known molding methods such as injection molding (including gas injection molding, two-color injection molding, core-back injection molding, and sandwich injection molding), injection compression molding (press injection), extrusion molding, sheet molding, and hollow molding. Of these, it is preferable to obtain it by injection molding or injection compression molding.

[0057] The molded articles of the present invention exhibit excellent dimensional stability (low coefficient of thermal expansion), balance of physical properties, and superior surface smoothness. Therefore, these properties can be balanced and applied to applications where they are highly required, such as automotive parts, various components for electrical and electronic equipment like televisions and vacuum cleaners, various industrial parts and building material components such as toilet seats and other housing equipment parts, and especially automotive interior and exterior parts such as instrument panels, glove boxes, trims, housings, pillars, bumpers, fenders, and back doors. For these reasons, the industrial value of this polypropylene resin composition and molded articles made therefrom is significant. [Examples]

[0058] The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The evaluation methods, analytical methods, and materials used in the examples are as follows. 1. Methods for measuring, evaluating, and analyzing physical properties (1) MFR: In accordance with JIS K 7210, the test was performed at 230°C and with a load of 2.16 kg. (2) Flexural modulus (unit: MPa): Measured in accordance with ISO 527, at a test temperature of 23°C and a test speed of 2 mm / min. The test specimens were dumbbell-shaped tensile test specimens (Type A) formed using a Toshiba Machine Co., Ltd. IS80G injection molding machine at a molding temperature of 200°C and a mold temperature of 40°C. The obtained measurement values ​​were compared with Examples 1, 4, and 8, which were reference examples with the same inorganic filler (C), and the following judgments were made. ○ Its physical properties are less than -10% compared to the standard material. △ Its physical properties are 10% to 20% lower compared to the standard material. × Its physical properties are more than -20% lower compared to the standard material. (3) Charpy impact strength (unit: kJ / m 2 ):Measurements were taken in accordance with ISO 179 (with notch) at a test temperature of 23°C. Test specimens were molded using a Toshiba Machine Co., Ltd. IS80G injection molding machine at a molding temperature of 200°C and a mold temperature of 40°C, with a notch (notch radius 0.25 mm), a thickness of 4.0 mm, a width of 10.0 mm, and a length of 80.0 mm. The obtained measurement values ​​were compared with Examples 1, 4, and 8, which were reference examples with the same inorganic filler (C), and the following judgments were made. ○ Its physical properties are less than -10% compared to the standard material. △ Its physical properties are 10% to 20% lower compared to the standard material. × Its physical properties are more than -20% lower compared to the standard material. (4) Coefficient of linear thermal expansion: A flat plate was manufactured by injection molding under the following conditions, and the coefficient of linear thermal expansion was used by cutting out a test piece. (4-1) Flat plate forming conditions Injection molding machine: NEX220 manufactured by Nissei Plastic Industrial Co., Ltd. Mold: Long flat sheet (L350mm x W100mm x t3mm, single side gate specification) Molding temperature: 220℃ Mold temperature: 40℃ Injection pressure: 80 MPa Holding pressure: 55MPa Injection speed: 30mm / sec Filling time: 3 seconds Cooling time: 20 seconds Next, a 10mm x 10mm x 3mm specimen was cut from the center of the specimen and annealed at 100°C for 1 hour to remove strain from the molding process, as well as to dehydrate and degas. (4-2) Measurement conditions The linear expansion coefficients in the flow direction and perpendicular to it of the resin were measured in compression mode using a linear expansion coefficient measuring device (Shimadzu Corporation "TMA-60") in accordance with JIS K-7197. The measurements were taken over a temperature range of 16°C to 85°C at a heating rate of 2°C / min, and the average linear expansion coefficient from 25°C to 80°C was measured. The average of the two measured values ​​was taken as the linear expansion coefficient. Here, a smaller linear expansion coefficient indicates better dimensional stability. The obtained measured values ​​were compared with Examples 1, 4, and 8, which use the same inorganic filler (C) as a reference, and the following judgments were made. ○ Its physical properties are less than +10% compared to the standard material. △ Its physical properties are +10% to +20% compared to the standard material. × Its physical properties are more than +20% higher compared to the standard material. (5) Surface smoothness Flat plate surface roughness Ra (unit: μm): Flat plates were manufactured by injection molding under the following conditions, and the surface roughness of the flat plates was measured. Here, the smaller the flat plate surface roughness Ra, the better the surface smoothness. (5-1) Flat plate forming conditions Injection molding machine: NEX220 manufactured by Nissei Plastic Industrial Co., Ltd. Mold: Long flat sheet (L350mm x W100mm x t3mm, single side gate specification) Molding temperature: 220℃ Mold temperature: 40℃ Injection pressure: 80 MPa Holding pressure: 55MPa Injection speed: 30mm / sec Filling time: 3 seconds Cooling time: 20 seconds (5-2) Measurement conditions Measuring instrument: Mitutoyo Corporation Surftest SJ-210 Stylus tip shape: Taper angle (60 degrees), tip radius (2 μm) Measuring force: 0.75mN Measurement method: The surface of the test specimens prepared as described above was measured in the MD direction (resin flow direction). The obtained measurement values ​​were compared with Examples 1, 4, and 8, which are reference examples with the same inorganic filler (C), and the following determinations were made. ○ Its physical properties are less than +10% compared to the standard material. △ Its physical properties are +10% to +20% compared to the standard material. × Its physical properties are more than +20% higher compared to the standard material.

[0059] The amount (ratio) of the ethylene-propylene random copolymer portion of a propylene-ethylene block copolymer, and the ethylene content of the ethylene-propylene random copolymer portion, can be quantified by the following method. (a) Analytical equipment to be used (a-1) Cross sorting device Dia Instruments CFC T-100 (abbreviated as CFC) (a-2) Fourier transform infrared absorption spectroscopy FT-IR, PerkinElmer 1760X The fixed-wavelength infrared spectrophotometer that was attached as the detector for the CFC was removed and replaced with an FT-IR, which was then used as the detector. The transfer line from the outlet of the solution eluted from the CFC to the FT-IR was 1 m long and maintained at 140°C throughout the measurement. The flow cell attached to the FT-IR had an optical path length of 1 mm and an optical path width of 5 mmφ and was also maintained at 140°C throughout the measurement. (a-3) Gel permeation chromatography (GPC) For the GPC column in the CFC downstream section, three Showa Denko AD806MS columns are used, connected in series.

[0060] (b) Measurement conditions for CFCs (b-1) Solvent: Orthodichlorobenzene (ODCB) (b-2) Sample concentration: 4 mg / ml (b-3) Injection amount: 0.4ml (b-4) Crystallization: Cool the temperature from 140°C to 40°C over approximately 40 minutes. (b-5) Separation method: During temperature-induced elution and fractionation, the fractionation temperatures are set to 40, 100, and 140°C, resulting in a total of three fractions. The elution ratios (in weight %) of the components that elute below 40°C (Fraction 1), those that elute between 40 and 100°C (Fraction 2), and those that elute between 100 and 140°C (Fraction 3) are defined as W40, W100, and W140, respectively. W40 + W100 + W140 = 100. Each separated fraction is then automatically transported to the FT-IR analyzer. (b-6) Solvent flow rate during elution: 1 ml / min

[0061] (c) FT-IR measurement conditions After the elution of the sample solution from the GPC following the CFC is initiated, FT-IR measurements are performed under the following conditions, and GPC-IR data is collected for each of the fractions 1 to 3 described above. (c-1) Detector: MCT (c-2) Resolution: 8cm -1 (c-3) Measurement interval: 0.2 minutes (12 seconds) (c-4) Number of cumulative measurements per measurement: 15

[0062] (d) Post-processing and analysis of measurement results The amount of eluted components and molecular weight distribution at each temperature were obtained by FT-IR at 2945 cm². -1 The absorbance is used as a chromatogram to determine the elution amount. The elution amount is normalized so that the sum of the elution amounts of each component equals 100%. The conversion from retention capacity to molecular weight is performed using a calibration curve prepared in advance using standard polystyrene. The standard polystyrene used is the following brands manufactured by Tosoh Corporation: F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, and A1000. A calibration curve is created by injecting 0.4 ml of a solution of each polystyrene dissolved in ODCB (containing 0.5 mg / ml BHT) so that the concentration is 0.5 mg / ml. The calibration curve is a cubic equation obtained by approximating it using the least squares method. For conversion to molecular weight, a general calibration curve is used, referring to "Size Exclusion Chromatography" by Sadao Mori (Kyoritsu Shuppan). The following values ​​are used for the viscosity formula ([η]=K×Mα). (d-1) When creating a calibration curve using standard polystyrene K=0.000138, α=0.70 (d-2) When measuring the sample of component (A) propylene-ethylene block copolymer K=0.000103, α=0.78 The ethylene content distribution of each eluted component (distribution of ethylene content along the molecular weight axis) is obtained by FT-IR at 2956 cm². -1 Absorbance and 2927cm² -1 The ethylene content is determined by converting it to weight %) using the ratio of absorbance to a calibration curve prepared in advance using polyethylene, polypropylene, ethylene-propylene rubber (EPR) whose ethylene content is known by 13C-NMR measurement, etc., and mixtures thereof.

[0063] (e) Ratio of ethylene-propylene random copolymer portion (Wc) In the present invention, the ratio (Wc) of the ethylene-propylene random copolymer portion in the propylene-ethylene block copolymer is theoretically defined by the following formula (I) and can be determined by the following procedure. Wc (weight%)=W40×A40 / B40+W100×A100 / B100…(I) In formula (I), W40 and W100 are the elution percentages (in weight %) in each fraction described above, A40 and A100 are the measured average ethylene content (in weight %) in each fraction corresponding to W40 and W100, and B40 and B100 are the ethylene content (in weight %) of the ethylene-propylene copolymer portion contained in each fraction. The methods for calculating A40, A100, B40, and B100 will be described later.

[0064] The meaning of equation (I) is as follows: The first term on the right side of equation (I) is the term used to calculate the amount of ethylene-propylene random copolymer contained in fraction 1 (the portion soluble at 40°C). If fraction 1 contains only the ethylene-propylene random copolymer and no propylene polymer, W40 directly contributes to the total content of the ethylene-propylene random copolymer derived from fraction 1. However, since fraction 1 also contains small amounts of propylene polymer derived components (components with extremely low molecular weight and atactic polypropylene) in addition to the components derived from ethylene-propylene random copolymer, it is necessary to correct for this portion. Therefore, by multiplying W40 by A40 / B40, the amount of fraction 1 derived from ethylene-propylene random copolymer is calculated. For example, if the average ethylene content of fraction 1 (A40) is 30% by weight, and the ethylene content of the ethylene-propylene random copolymer contained in fraction 1 (B40) is 40% by weight, then 30 / 40 = 3 / 4 (i.e., 75% by weight) of fraction 1 comes from the ethylene-propylene random copolymer, and 1 / 4 comes from the propylene polymer. Thus, multiplying by A40 / B40 in the first term on the right side means calculating the contribution of the ethylene-propylene random copolymer from the weight % of fraction 1 (W40). The second term on the right side is similar; the contribution of the ethylene-propylene random copolymer is calculated for each fraction and added together to obtain the partial content of the ethylene-propylene random copolymer.

[0065] (e-1) As described above, the average ethylene content corresponding to fractions 1 and 2 obtained by CFC measurement will be A40 and A100, respectively (all units are in weight percent). The method for determining the average ethylene content will be described later.

[0066] (e-2) B40 is defined as the ethylene content corresponding to the peak position in the differential molecular weight distribution curve of fraction 1 (unit is weight %). For fraction 2, it is assumed that the rubber portion will completely dissolve at 40°C, and therefore it cannot be defined in the same way; therefore, in this invention, B100 is substantially defined as 100. B40 and B100 are the ethylene content of the ethylene-propylene random copolymer portion contained in each fraction, but it is substantially impossible to analytically determine these values. This is because there is no means to completely separate and isolate the propylene polymer and ethylene-propylene random copolymer mixed in the fraction. Through studies using various model samples, it was found that using the ethylene content corresponding to the peak position of the differential molecular weight distribution curve of fraction 1 for B40 successfully explains the improvement effect on material properties. Furthermore, for two reasons—that B100 has crystallinity derived from the ethylene chain, and that the amount of ethylene-propylene random copolymer contained in these fractions is relatively small compared to the amount of ethylene-propylene random copolymer contained in fraction 1—approximating it to 100 is closer to reality and produces almost no error in calculations. Therefore, the analysis is performed with B100 = 100.

[0067] (e-3) For the reasons stated above, the ratio (Wc) of the ethylene-propylene random copolymer portion is determined according to the following formula (II). Wc (weight%)=W40×A40 / B40+W100×A100 / 100…(II) In other words, the first term on the right-hand side of equation (II), W40 × A40 / B40, represents the content (weight %) of non-crystalline ethylene-propylene random copolymer, and the second term, W100 × A100 / 100, represents the partial content (weight %) of crystalline ethylene-propylene random copolymer. Here, the average ethylene content A40 and A100 of each fraction 1 and 2 obtained by B40 and CFC measurements are determined as follows. The ethylene content corresponding to the peak position on the differential molecular weight distribution curve is B40. Furthermore, the sum of the products of the weight percentage and the ethylene content for each data point (captured as a data point during measurement) is the average ethylene content of fraction 1, A40. The average ethylene content of fraction 2, A100, is calculated similarly.

[0068] The significance of setting the three separation temperatures described above is as follows: In the CFC analysis of the present invention, 40°C is significant as a temperature condition that is necessary and sufficient to separate only non-crystalline polymers (for example, the majority of the ethylene-propylene random copolymer, or components with extremely low molecular weight and atactic components within the propylene polymer portion). 100°C is a temperature that is necessary and sufficient to elute only components that are insoluble at 40°C but soluble at 100°C (for example, components in the ethylene-propylene random copolymer that have crystalline properties due to the ethylene and / or propylene chain, and propylene polymers with low crystalline properties). 140°C is a temperature that is necessary and sufficient to elute only components that are insoluble at 100°C but soluble at 140°C (for example, components in the propylene polymer that have particularly high crystalline properties, and components in the ethylene-propylene random copolymer that have extremely high molecular weight and extremely high ethylene crystallinity), and to recover the entire amount of propylene-ethylene block copolymer used for analysis. Furthermore, since W140 contains either no ethylene-propylene random copolymer components at all, or only extremely small amounts, and is practically negligible, it is excluded from calculations of the ratio of ethylene-propylene random copolymers and the ethylene content of the ethylene-propylene random copolymer.

[0069] (f) Ethylene content of the ethylene-propylene random copolymer portion The ethylene content of the ethylene-propylene random copolymer portion of the propylene-ethylene block copolymer of component (A1) and component (A2) in the present invention can be determined using the values ​​described above and the following formulas. Ethylene content (by weight) of the ethylene-propylene random copolymer portion = (W40 × A40 + W100 × A100) / Wc However, Wc is the percentage (by weight) of the ethylene-propylene random copolymer portion determined earlier.

[0070] The intrinsic viscosity [η]copoly of the ethylene-propylene random copolymer portion in the propylene-ethylene block copolymer of component (A1) and component (A2) in the present invention can be determined as follows. First, after the polymerization of the crystalline propylene polymer portion is complete, a portion is sampled from the polymerization tank and its intrinsic viscosity [η]homo is measured. Next, after polymerizing the crystalline propylene polymer portion, the intrinsic viscosity [η]F of the final polymer (F) obtained by polymerizing the ethylene-propylene random copolymer portion is measured. This measurement is performed using an Ubbelohde viscometer with decalin as the solvent at a temperature of 135°C. [η]copoly is determined from the following relationship. [η]F=(100-Wc) / 100×[η]homo+Wc / 100×[η]copoly

[0071] 2.Material The following materials were used as raw materials in the examples and comparative examples. (1) Components (A1) and (A2): Propylene-ethylene block copolymer (A-1): A propylene-ethylene block copolymer with the following properties was used from "Novatec" manufactured by Nippon Polypropylene Co., Ltd. It contains a propylene polymer portion and an ethylene-propylene random copolymer portion. • Overall melt flow rate (230°C, 2.16 kg load): 120 g / 10 min • Propylene polymer content: 85% by weight • Content of ethylene-propylene random copolymer portion: 15% by weight • Melt flow rate of the propylene polymer portion: 230g / 10 min • Ethylene content of the ethylene-propylene random copolymer portion: 40% by weight • Intrinsic viscosity [η]c of the ethylene-propylene random copolymer portion: 2.5 dl / g (A-2): A propylene-ethylene block copolymer with the following properties was used from "Novatec" manufactured by Nippon Polypropylene Co., Ltd. It contains a propylene polymer portion and an ethylene-propylene random copolymer portion. • Overall melt flow rate (230°C, 2.16 kg load): 120 g / 10 min • Propylene polymer content: 90% by weight • Content of ethylene-propylene random copolymer portion: 10% by weight • Melt flow rate of the propylene polymer portion: 350g / 10 min • Ethylene content of the ethylene-propylene random copolymer portion: 45% by weight • Intrinsic viscosity [η]c of the ethylene-propylene random copolymer portion: 7.0 dl / g

[0072] (2) Component (B): Thermoplastic elastomer (B)-1: DuPont Dow's ethylene-octene copolymer "Engage 8100" (trade name). Melt flow rate (230°C, 2.16 kg load): 2 g / 10 min

[0073] (3) Component (C): Inorganic filler (C)-1: Luzenac HAR T84 (product name) manufactured by Imerys. Average particle size: 9.7 μm, aspect ratio: 18 (C)-2: "Micro Ace C-31" (product name) manufactured by Nippon Talc Co., Ltd. Average particle size: 6.2 μm, aspect ratio: 7.5 The average particle size was determined by a laser diffraction scattering particle size analyzer, specifically the particle size at 50% of the cumulative value in the particle size distribution. A Horiba LA-920 was used as the measuring device. (4)Optional addition ingredients • Phenolic antioxidant: Tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, manufactured by Ciba Specialty Chemicals, "Irganox 1010" (trade name) • Phosphate stabilizer: Tris(2,4-di-t-butylphenyl) phosphite, "Irgaphos 168" (trade name), manufactured by Ciba Specialty Chemicals. • Dispersant: Calcium stearate, manufactured by Nitto Chemical Industries, Ltd., "Calcium Stearate" (product name)

[0074] 3. Examples and Comparative Examples The above raw materials (A) to (C) were blended using a tumbler mixer in the proportions shown in Tables 1 to 3. Furthermore, 0.1 parts by weight of a phenolic antioxidant, 0.1 parts by weight of a phosphorus-based stabilizer, and 0.05 parts by weight of a dispersant were thoroughly mixed with 100 parts by weight of the total raw materials. The resulting mixture was kneaded and granulated using a twin-screw extruder (manufactured by Japan Steel Works: TEX30α) at ​​a resin temperature of 210°C to obtain a pelletized propylene resin composition. Test pieces for each evaluation were obtained by injection molding using the above resin composition. The blending and evaluation results of each material are shown in Tables 1, 2, and 3, respectively. In the evaluation of each item in relation to Examples 1, 4, and 8, one or more ×s were classified as "×× (very bad)", two △s as "× (bad)", only one △ as "△ (acceptable range)", and no ×s or △s as "〇 (good)" for an overall judgment.

[0075] [Table 1]

[0076] [Table 2]

[0077] [Table 3]

[0078] 4. Evaluation As shown in Tables 1, 2, and 3, the propylene resin compositions having the compositions shown in Examples 1 to 8, which satisfy each of the essential constituent requirements of the present invention, and the members obtained by injection molding them, all possess excellent moldability (high fluidity), balance of physical properties (high rigidity, high impact strength), dimensional stability (low coefficient of thermal expansion), and superior surface appearance quality of the products. It has been confirmed that these compositions clearly possess performance suitable for industrial parts, preferably automotive parts, such as door trims, instrument panels, pillars, bumpers, side moldings, door protectors, side protectors, back doors, fenders, rear gates, fender accessories, and other fender-related parts, and especially preferably automotive exterior parts such as bumpers, back doors, fenders, rear gates, and fender accessories.

[0079] On the other hand, the propylene-based resin compositions having the compositions shown in Comparative Examples 1 to 7, and the components obtained by injection molding them, have a poor balance of performance and are inferior in comparison. For example, in Comparative Example 1, although the fluidity and smoothness (flat surface roughness Ra) of the propylene resin composition were equivalent to those of Example 2, differences were observed in impact strength and dimensional stability (coefficient of linear expansion). This indicates that component A1 significantly improved dimensional stability (coefficient of linear expansion), and that it is essential that component A1 satisfies the scope of the present invention. Furthermore, in Comparative Example 2, although the dimensional stability (coefficient of linear expansion) of the propylene resin composition was equivalent to that of Example 1, differences were observed in the balance of physical properties (rigidity, impact strength) and the smoothness of the product surface (flat plate surface roughness Ra). This indicates that component A2 significantly improved the smoothness (flat plate surface roughness Ra), and that it is essential that component A2 satisfies the scope of the present invention. Furthermore, in Comparative Example 3, although the smoothness (flat surface roughness Ra) of the propylene-based resin composition was equivalent to that of Example 4, differences were observed in fluidity and dimensional stability (coefficient of linear expansion). This indicates that component A1 significantly improved dimensional stability (coefficient of linear expansion), and that it is essential that component A1 satisfies the scope of the present invention. Furthermore, in Comparative Example 4, although the fluidity, rigidity, and dimensional stability (coefficient of linear expansion) of the propylene resin composition were equivalent to those of Example 4, differences were observed in impact strength and surface smoothness (flat plate surface roughness Ra). This indicates that component A2 significantly improved smoothness (flat plate surface roughness Ra), and that it is essential that component A2 satisfies the scope of the present invention. Furthermore, in Comparative Example 5, although the fluidity and rigidity of the propylene-based resin composition were better than those in Example 4, the impact strength, dimensional stability (coefficient of linear expansion), and surface smoothness of the product (flat plate surface roughness Ra) were poor. This indicates that in order to satisfy the balance of each performance characteristic, it is essential that component B meets the scope of the present invention. Furthermore, in Comparative Example 6, although the fluidity and rigidity of the propylene resin composition were equivalent to those of Example 8, differences were observed in dimensional stability (coefficient of linear expansion) and smoothness (surface roughness Ra of the flat plate). This indicates that component A2 significantly improved the balance between dimensional stability (coefficient of linear expansion) and smoothness (surface roughness Ra of the flat plate), and that it is essential for component A2 to satisfy the scope of the present invention. Furthermore, in Comparative Example 7, although the rigidity and impact properties of the propylene-based resin composition were equivalent to those of Example 8, a difference in dimensional stability (coefficient of linear expansion) was observed. This indicates that component A1 significantly improved dimensional stability (coefficient of linear expansion), and that it is essential that component A1 satisfies the scope of the present invention.

[0080] Based on the results of each example and comparative example described above, the rationality and significance of the configuration and requirements of the present invention are demonstrated, and the superiority of the present invention over the prior art is also clear. [Industrial applicability]

[0081] The propylene resin composition of the present invention and molded articles using the same exhibit excellent moldability (high fluidity), dimensional stability (low coefficient of thermal expansion), and balance of physical properties (high rigidity, high impact strength), as well as good surface appearance quality of the product. These properties make them suitable for industrial parts, preferably automotive parts, such as door trims, instrument panels, pillars, bumpers, side moldings, door protectors, side protectors, back doors, fenders, rear gates, fender accessories, and other fender-related parts. Particularly preferred are automotive exterior parts such as bumpers, back doors, fenders, rear gates, and fender accessories.

Claims

1. A propylene-ethylene block copolymer (A1) satisfying the following characteristic (A1-1) is 5 to 95% by weight, 5 to 95% by weight of a propylene-ethylene block copolymer (A2) that satisfies the following characteristic (A2-1) (The total amount of the propylene-ethylene block copolymer (A1) and the propylene-ethylene block copolymer (A2) is 100% by weight) and contains A polypropylene resin (A) that satisfies the following characteristic (A-1), Thermoplastic elastomer (B) and It contains an inorganic filler (C) which is talc with an average particle diameter exceeding 8.5 μm and an aspect ratio exceeding 10. A propylene-based resin composition characterized by satisfying the following condition (a). Characteristics (A1-1) Propylene-ethylene block copolymer (A1) is It contains a propylene polymer portion (a11) and an ethylene-propylene random copolymer portion (a12), The intrinsic viscosity [η] of the ethylene-propylene random copolymer portion (a12), measured at 135°C in decalin solution, is 1.5 to 4.5 dl / g. Characteristics (A2-1) The propylene-ethylene block copolymer (A2) contains a propylene polymer portion (a21) and an ethylene-propylene random copolymer portion (a22). The intrinsic viscosity [η] of the ethylene-propylene random copolymer portion (a22), measured at 135°C in decalin solution, is 5.0–9.5 dl / g. Characteristics (A-1) Polypropylene resin (A) has an overall melt flow rate (230°C, 2.16 kg load) of 10 to 200 g / 10 min. Condition (a) The propylene resin composition comprises 30 to 90% by weight of a polypropylene resin (A), 5 to 30% by weight of a thermoplastic elastomer (B), and 5 to 40% by weight of an inorganic filler (C) (provided that the total amount of the polypropylene resin (A), thermoplastic elastomer (B), and inorganic filler (C) is 100% by weight).

2. The propylene-ethylene block copolymer (A1) further satisfies the following properties (A1-2) to (A1-5) in the propylene-ethylene block copolymer (A1) according to claim 1. Characteristics (A1-2) The melt flow rate of the propylene polymer portion (a11) (230°C, 2.16 kg load) is 100 g / 10 min or more. Characteristics (A1-3) The proportion of the ethylene-propylene random copolymer portion (a12) to the total propylene-ethylene block copolymer (A1) is 10 to 30% by weight. Characteristics (A1-4) The total melt flow rate of the propylene-ethylene block copolymer (A1) (230°C, 2.16 kg load) is 20 to 150 g / 10 min. Characteristics (A1-5) The ethylene content of the ethylene-propylene random copolymer portion (a12) is 30 to 50% by weight.

3. The propylene-ethylene block copolymer (A2) further satisfies the following properties (A2-2) to (A2-5) of the propylene-ethylene block copolymer (A2) according to claim 1. Characteristics (A2-2) The melt flow rate of the propylene polymer portion (a21) (230°C, 2.16 kg load) is 250 g / 10 min or more. Characteristics (A2-3) The proportion of the ethylene-propylene random copolymer portion (a22) to the total propylene-ethylene block copolymer (A2) is 5 to 25% by weight. Characteristics (A2-4) The total melt flow rate of the propylene-ethylene block copolymer (A2) (230°C, 2.16 kg load) is 20–120 g / 10 min. Characteristics (A2-5) The ethylene content of the ethylene-propylene random copolymer portion (a22) is 30 to 50% by weight.

4. A molded article obtained by molding a propylene-based resin composition according to any one of claims 1 to 3.

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