Propylene resin composition and molded article

Abstract

To provide a molded article which has excellent flame retardancy and in which the amount of deformation due to contact with flame can be reduced and suppressed to the same level while containing fibers, and to provide a propylene-based resin composition from which the molded article can be produced.SOLUTION: A polypropylene-based resin composition containing a polypropylene-based polymer (A), a flame retardant (B), and a fiber (C), wherein the fiber (C) contains a fiber having a flat cross-sectional shape in which the ratio of the major axis to the minor axis [major axis / minor axis] in the cross section is 2.0 or more, and a molded article containing the polypropylene-based resin composition.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a propylene-based resin composition and a molded article. [Background technology]

[0002] Polypropylene-based resins have excellent moldability and are used in a variety of applications, such as as materials for interior and exterior components for automobiles. Among automotive components, those requiring flame retardancy have traditionally been made from metal, but in recent years, efforts have been made to replace these with molded articles made from resin compositions in order to reduce their weight. Molded articles made from resin compositions that replace metal components require not only flame retardancy but also rigidity. Flame-retardant polyolefin-based resin compositions have attracted attention as resin compositions that exhibit such properties. For example, a polypropylene-based resin composition containing a polypropylene-based polymer (A), a flame retardant (B), and glass fibers (C) having an aspect ratio of 20 to 60 has been proposed (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2022 / 030480 Summary of the Invention [Problem to be solved by the invention]

[0004] Molded articles made from resin compositions containing (reinforcing) fibers such as glass fibers are generally prone to anisotropy in the fiber arrangement during molding, resulting in inconsistent rigidity and deformability. Furthermore, when flame-retardant molded articles are exposed to flame, they undergo changes over time, including softening of the base resin, thermal decomposition (lowering of molecular weight), and chemical changes such as the flame-retardant action of the flame retardant (e.g., formation of a carbonized foam layer). As these changes over time progress, the molded article melts and sags near the flame-contact area, a phenomenon known as "melt sagging." In this case, in resin compositions containing fibers, the amount of deformation due to flame contact, i.e., the amount of melt sagging, becomes uneven near the flame-contact area.

[0005] An object of the present invention is to provide a molded article that has excellent flame retardancy and that, despite containing fibers, can reduce or maintain the amount of deformation due to flame contact at an equivalent level, and a propylene-based resin composition from which the molded article can be produced. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above problems and have found that by using fibers having a flat cross section in which the ratio of the long axis to the short axis in the cross section [long axis / short axis] is 2.0 or more, instead of the conventionally commonly used circular cross section fibers, as the fibers to be contained in a propylene-based resin composition, it is possible to maintain excellent flame retardancy even if anisotropic fiber arrangement occurs in the molded article, and even if deformation due to flame contact causes melt dripping, the amount of deformation can be kept small overall and at the same level.The present invention was completed based on these findings and further research.

[0007] That is, the object of the present invention has been achieved by the following means. [1] A polypropylene-based resin composition comprising a polypropylene-based polymer (A), a flame retardant (B), and a fiber (C), The polypropylene-based resin composition, wherein the fibers (C) have a flat cross-sectional shape in which the ratio of the major axis to the minor axis in the cross section [major axis / minor axis] is 2.0 or more. [2] The polypropylene resin composition according to [1], wherein the fiber (C) is a glass fiber. [3] The polypropylene resin composition according to [1] or [2], wherein the fibers (C) are glass fiber chopped strands. [4] The polypropylene resin composition according to any one of [1] to [3], wherein the weight average fiber length of the fibers (C) is 200 to 800 μm. [5] The polypropylene resin composition according to any one of [1] to [4], wherein the flame retardant (B) comprises a phosphorus-containing flame retardant. [6] The polypropylene resin composition according to any one of [1] to [5], wherein the flame retardant (B) includes an intumescent flame retardant. [7] When the total amount of the polypropylene resin composition is 100% by mass, the content of the polypropylene polymer (A) is 25 to 70% by mass, The content of the flame retardant (B) is 5 to 50 mass %, The content of fiber (C) is 5 to 50 mass%. The polypropylene resin composition according to any one of [1] to [6]. [8] The polypropylene resin composition according to any one of [1] to [7], further comprising an acid-modified polyolefin polymer (D). [9] When the total amount of the polypropylene resin composition is 100% by mass, The polypropylene resin composition according to [8], wherein the content of the acid-modified polyolefin polymer (D) is 0.1 to 5.0% by mass.

[10] A molded article comprising the polypropylene resin composition according to any one of the above [1] to [9].

[11] An injection-molded article comprising the polypropylene resin composition according to any one of the above [1] to [9]. [Effects of the Invention]

[0008] The present invention can provide a molded article that has excellent flame retardancy and that, despite containing fibers, can reduce the amount of deformation due to flame contact and keep it at the same level as that of a molded article, and a propylene-based resin composition from which the molded article can be produced. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be specifically described below, but is not limited to the specific embodiments shown below.

[0010] [[Terminology Explanation]] Before describing the present invention, commonly used terms will first be explained. In the present invention and this specification, the term "monomer unit" refers to a structural unit (residue) derived from a monomer contained in a polymer obtained by polymerizing a monomer. In the present invention and this specification, the term "α-olefin" refers to an olefin having a terminal (α-position) carbon-carbon double bond. In the present invention and this specification, the bonding mode (arrangement of the structural units) of two or more structural units in a copolymer that becomes a resin or elastomer is not particularly limited, and unless otherwise specified, may be any bonding mode, such as random bonding (random copolymer), block bonding (block copolymer), alternating bonding (alternating copolymer), or graft bonding (graft copolymer).

[0011] In the present invention and this specification, unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass".

[0012] In the present invention and this specification, when describing content, physical properties, etc., by indicating a numerical range, if the upper and lower limits of the numerical range are described separately, any of the upper and lower limits can be appropriately combined to form a specific numerical range. On the other hand, when describing multiple numerical ranges expressed using "to", the upper and lower limits forming the numerical range are not limited to the specific combination written before and after "to" as a specific numerical range, but can be a numerical range obtained by appropriately combining the upper and lower limits of each numerical range. Note that in the present invention and this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the upper and lower limits.

[0013] In the present invention and this specification, the term "melt flow rate (MFR)" means "melt mass flow rate" and, unless otherwise specified, is the melt flow rate (unit: g / 10 min) measured in accordance with JIS K 7210-1:2014 and JIS K 7210-2:2014 under conditions of a temperature of 230°C and a load of 2.16 kgf.

[0014] In the present invention and this specification, the "intrinsic viscosity (unit: dL / g)" is a value measured at a temperature of 135°C using tetralin as a solvent by the following method. The intrinsic viscosity is determined by the "extrapolation method," in which the reduced viscosity is measured at multiple concentrations using an Ubbelohde viscometer, the reduced viscosity is plotted against the concentration, and the concentration is extrapolated to zero. More specifically, the intrinsic viscosity is determined by the method described on page 491 of "Polymer Solutions, Polymer Experiments 11" (published by Kyoritsu Publishing in 1982), in which the reduced viscosity is measured at three concentrations of 0.1 g / dL, 0.2 g / dL, and 0.5 g / dL, the reduced viscosity is plotted against the concentration, and the concentration is extrapolated to zero.

[0015] [[Polypropylene resin composition]] The polypropylene resin composition of the present invention contains a polypropylene polymer (A), a flame retardant (B), and fibers (C). The fibers (C) include fibers having a flat cross-sectional shape with a ratio of the major axis to the minor axis in the cross-section [major axis / minor axis] of 2.0 or more. The polypropylene resin composition of the present invention, which contains fibers having the above-described flat cross-sectional shape as fiber (C) (hereinafter sometimes referred to as "flat fibers"), exhibits excellent flame retardancy. Furthermore, when molded into a molded article, the polypropylene resin composition of the present invention suppresses softening and melting near the flame-contact area even when exposed to flame, and can keep the amount of deformation (melt sagging) small and at a constant level overall. In particular, when a molded article is formed by injection molding, the polypropylene resin composition of the present invention can effectively suppress deformation in the transverse direction (TD), which is prone to deformation due to the anisotropic arrangement of fiber (C). As a result, the difference between deformation in the machine direction (MD) can be reduced, and an injection-molded article can be realized in which deformation in the TD and MD can be kept at a constant level. Furthermore, the polypropylene resin composition of the present invention can suppress not only the amount of deformation due to flame contact but also preferably the non-uniformity of the amount of deformation of a molded article due to the arrangement anisotropy that generally occurs in molded articles containing fibers, and can also suppress the amount of deformation to an equivalent level overall (exhibit high rigidity). In particular, the polypropylene resin composition of the present invention can effectively suppress the amount of deformation in the TD direction as well, reducing the difference with the amount of deformation in the MD, thereby realizing an injection-molded article in which the amounts of deformation due to the arrangement anisotropy in both the TD and MD can be suppressed to an equivalent level. Molded articles formed from the polypropylene resin composition of the present invention are generally resistant to deformation, and the amount of deformation is highly suppressed regardless of the arranging direction of the fibers (C).

[0016] First, the components contained in the polypropylene resin composition of the present invention will be described. The polypropylene resin composition of the present invention may contain one or more types of each component.

[0017] [Polypropylene polymer (A)] The polypropylene polymer (A) refers to a polymer containing more than 50% by mass of units derived from propylene (also referred to as "propylene units") relative to the total structural units of the polymer (100% by mass). The propylene units in the polypropylene polymer (A) are usually 100% by mass or less.

[0018] Examples of polypropylene polymers include propylene homopolymers and copolymers obtained by polymerizing propylene and one or more other monomers copolymerizable with propylene in any combination in any ratio. The copolymers may be random copolymers or block copolymers.

[0019] The polypropylene resin composition may contain, as the polypropylene polymer (A), one kind of polypropylene polymer alone, or may contain two or more kinds of polypropylene polymers in any combination in any ratio.

[0020] Examples of single-type polypropylene-based polymers include propylene homopolymers and random copolymers of propylene with one or more other monomers copolymerizable therewith (e.g., ethylene, α-olefins having 4 or more carbon atoms) (hereinafter also referred to as polypropylene-based random copolymers). Examples of combinations of two or more polypropylene polymers include a combination of two or more propylene homopolymers having different weight average molecular weights, and a combination of the following polymer (I) and polymer (II).

[0021] The polypropylene-based resin composition may contain a heterophasic propylene polymer material as the polypropylene-based polymer. Here, the term "heterophagic propylene polymer material" refers to a material containing two or more polypropylene-based polymers that are incompatible with each other and form separate phases. Examples of heterophasic propylene polymer materials include a combination of polymer (I) and polymer (II) shown below. Polymer (I) is a polymer containing propylene units in an amount of more than 80% by mass and up to 100% by mass of all structural units, and may be a propylene homopolymer or a copolymer of propylene and the other monomers described above. Polymer (II) is a copolymer of propylene units and at least one monomer unit selected from the group consisting of ethylene units and α-olefin units having 4 or more carbon atoms. Polymer (I) and polymer (II) may each be a single polymer or a combination of two or more polymers.

[0022] From the viewpoint of improving the rigidity and impact resistance of the molded body, the polypropylene-based polymer is preferably one or more selected from the group consisting of propylene homopolymers and heterophasic propylene polymer materials, and more preferably propylene homopolymers.

[0023] In the present invention, the polystyrene-equivalent weight average molecular weight of the polypropylene polymer (A) is usually 1,000 to 1,000,000, and preferably 5,000 to 1,000,000, from the viewpoint of improving the appearance and elongation properties of the molded article.

[0024] From the viewpoint of improving the rigidity of molded articles, polypropylene-based polymers are 13 The isotactic pentad fraction (also called the [mmmm] fraction) measured by C-NMR is preferably 0.96 or more, more preferably 0.97 or more. The closer the isotactic pentad fraction of a polypropylene polymer is to 1, the higher the stereoregularity of the molecular structure of the polypropylene polymer, and the higher the crystallinity of the polypropylene polymer. When the polypropylene polymer is a copolymer, the isotactic pentad fraction can be measured for the chain of propylene units in the copolymer.

[0025] From the viewpoint of improving the molding processability of the polypropylene resin composition of the present invention, the polypropylene polymer preferably has a melt flow rate (MFR) of 1 g / 10 min or more, more preferably 10 g / 10 min or more, and preferably 500 g / 10 min or less, and even more preferably 10 to 300 g / 10 min.

[0026] The polypropylene polymer can be produced, for example, by the following polymerization method using a polymerization catalyst.

[0027] Polymerization catalysts include Ziegler-type catalyst systems, Ziegler-Natta-type catalyst systems, catalyst systems containing a Group 4 transition metal compound with a cyclopentadienyl ring and an alkylaluminoxane, catalyst systems containing a Group 4 transition metal compound with a cyclopentadienyl ring, a compound that reacts with the metal to form an ionic complex, and an organoaluminum compound, and catalyst systems in which catalyst components (e.g., a Group 4 transition metal compound with a cyclopentadienyl ring, a compound that forms an ionic complex, or an organoaluminum compound) are supported on inorganic particles (e.g., silica, clay minerals, etc.) and modified. Prepolymerization catalysts prepared by prepolymerizing monomers such as ethylene or α-olefins in the presence of such catalyst systems may also be used. Ziegler-Natta-type catalyst systems include catalyst systems that use a titanium-containing solid transition metal component in combination with an organometallic component.

[0028] Examples of such catalyst systems include those described in JP-A-61-218606, JP-A-5-194685, JP-A-7-216017, JP-A-9-316147, JP-A-10-212319, and JP-A-2004-182981. In this specification, the contents of the above-mentioned patent documents can be referenced as appropriate, and the contents thereof are incorporated as is into this specification as part of the description thereof.

[0029] Polymerization methods include bulk polymerization, solution polymerization (liquid phase polymerization), and gas phase polymerization. Here, bulk polymerization refers to a method in which polymerization is carried out using a liquid olefin as a medium at the polymerization temperature. Solution polymerization refers to a method in which polymerization is carried out in an inert hydrocarbon solvent such as propane, butane, isobutane, pentane, hexane, heptane, or octane. Gas phase polymerization refers to a method in which gaseous monomers are used as a medium and the gaseous monomers are polymerized in that medium.

[0030] The polymerization method may be carried out by a batch system, a continuous system, or a combination thereof. The polymerization method may be a multi-stage system using a plurality of polymerization reactors connected in series.

[0031] Various conditions in the polymerization method (polymerization temperature, polymerization pressure, monomer concentration, catalyst input amount, polymerization time, etc.) can be appropriately determined depending on the desired polypropylene polymer.

[0032] In the production of a polypropylene-based polymer, in order to remove residual solvents contained in the obtained polypropylene-based polymer and ultralow molecular weight oligomers by-produced during the production, the obtained polypropylene-based polymer may be maintained at a temperature at which impurities such as the residual solvent and oligomers can volatilize but which is lower than the temperature at which the polypropylene-based polymer melts. Methods for removing impurities such as residual solvents and oligomers include, for example, the methods described in JP-A-55-75410 and JP-A-2565753. The contents of these patent documents can be referenced in this specification as appropriate, and the contents thereof are incorporated herein as is.

[0033] <Propylene homopolymer> From the viewpoint of improving the fluidity of the polypropylene-based resin composition of the present invention when melted and the toughness of a molded article containing the polypropylene-based resin composition, the propylene homopolymer preferably has an intrinsic viscosity [η] of 0.1 to 2 dL / g, more preferably 0.5 to 1.5 dL / g, and even more preferably 0.7 to 1.4 dL / g.

[0034] From the viewpoint of improving the fluidity of the polypropylene resin composition of the present invention when melted and the toughness of a molded article containing the polypropylene resin composition of the present invention, the propylene homopolymer preferably has a molecular weight distribution Mw / Mn of 3 or more and less than 7, more preferably 3 to 5. Here, Mw represents the weight-average molecular weight, and Mn represents the number-average molecular weight. The molecular weight distribution is a value measured by gel permeation chromatography (also known as GPC).

[0035] <Polypropylene random copolymer> Examples of polypropylene random copolymers include a random copolymer containing propylene units and units derived from ethylene (also referred to as "ethylene units") (hereinafter also referred to as "random copolymer (1)"), a random copolymer containing propylene units and units derived from an α-olefin having 4 or more carbon atoms (hereinafter also referred to as "olefin units") (hereinafter also referred to as "random polymer (2)"), and a random copolymer containing propylene units, ethylene units, and olefin units (hereinafter also referred to as "random polymer (3)").

[0036] The α-olefin having 4 or more carbon atoms that can constitute the polypropylene random copolymer may be a linear olefin, a branched olefin, or a cyclic olefin. The α-olefin is preferably an α-olefin having 4 to 10 carbon atoms. Examples of the α-olefin having 4 to 10 carbon atoms include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene, with 1-butene, 1-hexene, and 1-octene being preferred. Examples of cyclic olefins include vinylcyclopropane and vinylcyclobutane.

[0037] Examples of the random copolymer (2) include a propylene-1-butene random copolymer, a propylene-1-hexene random copolymer, a propylene-1-octene random copolymer, and a propylene-1-decene random copolymer.

[0038] Examples of the random copolymer (3) include a propylene-ethylene-1-butene copolymer, a propylene-ethylene-1-hexene copolymer, a propylene-ethylene-1-octene copolymer, and a propylene-ethylene-1-decene copolymer.

[0039] The content of ethylene units in the random copolymer (1) is not particularly limited, but is preferably 0.1 to 40 mass %, more preferably 0.1 to 30 mass %, and even more preferably 2 to 15 mass %. The content of the olefin unit in the random copolymer (2) is not particularly limited, but is preferably 0.1 to 40 mass %, more preferably 0.1 to 30 mass %, and even more preferably 2 to 15 mass %. The total content of ethylene units and olefin units in the random copolymer (3) is not particularly limited, but is preferably 0.1 to 40 mass%, more preferably 0.1 to 30 mass%, and even more preferably 2 to 15 mass%.

[0040] The content of propylene units in these random copolymers (1) to (3) is not particularly limited, but is preferably 60 to 99.9 mass%, more preferably 70 to 99.9 mass%, and even more preferably 85 to 98 mass%.

[0041] <Heterophasic propylene polymer material> As described above, polymer (I) is a polymer having propylene units in an amount of more than 80 mass% and not more than 100 mass% of all constituent units. The total content of monomer units other than propylene units in polymer (I), where the mass of polymer (I) is taken as 100 mass%, is usually 0 mass% or more and less than 20 mass%, and may be 0 mass% or more than 0.01 mass%.

[0042] Examples of other monomer units than propylene units that may be contained in the polymer (I) include ethylene units and α-olefin units having 4 or more carbon atoms. The α-olefin having 4 or more carbon atoms that can constitute the polymer (I) may be a linear olefin, a branched olefin, or a cyclic olefin. The α-olefin is the same as the α-olefin having 4 or more carbon atoms in the polypropylene random copolymer, preferably an α-olefin having 4 to 10 carbon atoms, more preferably 1-butene, 1-hexene, 1-octene, and 1-decene, and even more preferably 1-butene.

[0043] Examples of polymer (I) include propylene homopolymer, propylene-ethylene copolymer, propylene-1-butene copolymer, propylene-1-hexene copolymer, propylene-1-octene copolymer, propylene-ethylene-1-butene copolymer, propylene-ethylene-1-hexene copolymer, and propylene-ethylene-1-octene copolymer.

[0044] Among these, preferred polymers (I) are propylene homopolymers, propylene-ethylene copolymers, propylene-1-butene copolymers, and propylene-ethylene-1-butene copolymers, and from the viewpoint of the rigidity of a molded article containing the polypropylene resin composition of the present invention, propylene homopolymers are particularly preferred.

[0045] As described above, the polymer (II) is a copolymer of propylene units and at least one other monomer unit selected from the group consisting of ethylene units and α-olefin units having 4 or more carbon atoms.

[0046] The polymer (II) is preferably a polymer containing propylene units in an amount of more than 0% by mass and not more than 90% by mass, more preferably more than 0% by mass and not more than 80% by mass, based on the mass of all structural units. The polymer (II) may be a random copolymer or a block copolymer. The total content of ethylene units and α-olefin units having 4 or more carbon atoms in polymer (II) is preferably 20 to 80 mass%, more preferably 20 to 60 mass%, based on 100 mass% of the mass of polymer (II).

[0047] The α-olefin having 4 or more carbon atoms that can constitute polymer (II) is preferably an α-olefin having 4 to 10 carbon atoms, similar to the α-olefin that can constitute polymer (I).

[0048] Examples of the polymer (II) include a propylene-ethylene copolymer, a propylene-ethylene-1-butene copolymer, a propylene-ethylene-1-hexene copolymer, a propylene-ethylene-1-octene copolymer, a propylene-ethylene-1-decene copolymer, a propylene-1-butene copolymer, a propylene-1-hexene copolymer, a propylene-1-octene copolymer, and a propylene-1-decene copolymer. The polymer (II) is preferably a propylene-ethylene copolymer, a propylene-1-butene copolymer, or a propylene-ethylene-1-butene copolymer, and more preferably a propylene-ethylene copolymer.

[0049] The content of polymer (II) in the heterophasic propylene polymerization material is not particularly limited, but is preferably 1 to 50 mass%, more preferably 1 to 40 mass%, even more preferably 5 to 30 mass%, and particularly preferably 8 to 15 mass%, based on 100 mass% of the total mass of polymer (I) and polymer (II).

[0050] In the heterophasic propylene polymerization material, the combination of polymer (I) and polymer (II) is not particularly limited, and may be any suitable combination of polymers, preferably a combination of a preferred polymer (I) and a preferred polymer (II). Examples of heterophasic propylene polymer materials include the following polymer combinations in which polymer (I) is a propylene homopolymer. A combination of a propylene homopolymer and a (propylene-ethylene) copolymer, a combination of a propylene homopolymer and a (propylene-ethylene-1-butene) copolymer, a combination of a propylene homopolymer and a (propylene-ethylene-1-hexene) copolymer, a combination of a propylene homopolymer and a (propylene-ethylene-1-octene) copolymer, a combination of a propylene homopolymer and a (propylene-1-butene) copolymer, a combination of a propylene homopolymer and a (propylene-1-hexene) copolymer, a combination of a propylene homopolymer and a (propylene-1-octene) copolymer, and a combination of a propylene homopolymer and a (propylene-1-decene) copolymer.

[0051] Examples of heterophasic propylene polymer materials include the following combinations of polymers, in which polymer (I) is a polymer containing propylene units and monomer units other than propylene units: Here, the type of polymer (I) is described first, followed by the type of polymer (II). A combination of a (propylene-ethylene) copolymer and a (propylene-ethylene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-ethylene-1-butene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-ethylene-1-hexene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-ethylene-1-octene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-ethylene-1-decene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-ethylene-1-decene) copolymer, a combination of a (propylene-1-butene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-1-hexene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-1-octene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-1-decene) copolymer, a combination of a (propylene-1-butene) copolymer and a (propylene-ethylene) copolymer, a combination of a (propylene-1-butene) copolymer and a (propylene-ethylene-1-butene) copolymer, a combination of a (propylene a combination of a (propylene-1-butene) copolymer and a (propylene-ethylene-1-hexene) copolymer, a combination of a (propylene-1-butene) copolymer and a (propylene-ethylene-1-octene) copolymer, a combination of a (propylene-1-butene) copolymer and a (propylene-ethylene-1-decene) copolymer, a combination of a (propylene-1-butene) copolymer and a (propylene-1-butene) copolymer, a combination of a (propylene-1-butene) copolymer and a (propylene-1-hexene) copolymer, a combination of a (propylene-1-butene) copolymer and a (propylene-1-hexene) copolymer, a combination of a (propylene-1-butene) copolymer and a (propylene-1-butene) copolymer a combination of a (propylene-1-butene) copolymer and a (propylene-1-decene) copolymer; a combination of a (propylene-1-hexene) copolymer and a (propylene-1-hexene) copolymer; a combination of a (propylene-1-hexene) copolymer and a (propylene-1-octene) copolymer; a combination of a (propylene-1-hexene) copolymer and a (propylene-1-decene) copolymer; a combination of a (propylene-1-octene) copolymer and a (propylene-1-octene) copolymer; anda combination of a (propylene-1-octene) copolymer and a (propylene-1-decene) copolymer;

[0052] The heterophasic propylene polymer material that can be contained in the polypropylene-based resin composition of the present invention is preferably a combination of a propylene homopolymer and a (propylene-ethylene) copolymer, a combination of a propylene homopolymer and a (propylene-ethylene-1-butene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-ethylene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-ethylene-1-butene) copolymer, and a combination of a (propylene-1-butene) copolymer and a (propylene-1-butene) copolymer, and more preferably a combination of a propylene homopolymer and a (propylene-ethylene) copolymer.

[0053] The heterophasic propylene polymer material can be produced by multi-stage polymerization comprising a first polymerization step of producing polymer (I) and a second polymerization step of producing polymer (II) in the presence of polymer (I) produced in the first polymerization step. The polymerization can be carried out using the catalyst system exemplified above as a catalyst that can be used in the production of polypropylene-based polymers.

[0054] The intrinsic viscosity (hereinafter referred to as [η]I) of the polymer (I) is preferably 0.1 to 2 dL / g, more preferably 0.5 to 1.5 dL / g, and even more preferably 0.7 to 1.3 dL / g.

[0055] The intrinsic viscosity (hereinafter referred to as [η]II) of the polymer (II) is preferably 1 to 10 dL / g, more preferably 2 to 10 dL / g, and even more preferably 5 to 8 dL / g.

[0056] The ratio of [η]II to [η]I ([η]II / [η]I) is preferably 1-20, more preferably 2-10, and even more preferably 2-9.

[0057] When the polypropylene-based polymer is a polymerization material composed of polymer (I) and polymer (II) formed by multistage polymerization, a portion of the polymer formed in the first polymerization stage is extracted from the polymerization vessel to determine its intrinsic viscosity, and the intrinsic viscosity of the polymerization material finally obtained by the multistage polymerization (hereinafter referred to as [η]Total) is determined, and the intrinsic viscosity of the polymer formed in the second polymerization stage can be calculated using these intrinsic viscosity values ​​and the content of each polymer.

[0058] Furthermore, when a polymeric material consisting of polymer (I) and polymer (II) is a material produced by a method in which polymer (I) is obtained in an earlier polymerization step and polymer (II) is obtained in a later polymerization step, the procedures for measuring and calculating the contents and intrinsic viscosities ([η] Total, [η] I, and [η] II) of each of polymer (I) and polymer (II) are as follows.

[0059] The intrinsic viscosity [η]II of polymer (II) can be calculated from the intrinsic viscosity ([η]I) of polymer (I) obtained in the previous polymerization step, the intrinsic viscosity ([η]Total) of the final polymer after the subsequent polymerization step (i.e., the polymer material consisting of polymer (I) and polymer (II)) measured by the above method, and the content of polymer (II) contained in the final polymer, using the following formula. [η]II=([η]Total-[η]I×XI) / XII In the above formula, [η]Total: Intrinsic viscosity of the final polymer (unit: dL / g) [η]I: Intrinsic viscosity of polymer (I) (unit: dL / g) XI: Mass ratio of polymer (I) to final polymer XII: Mass ratio of polymer (II) to final polymer XI and XII can be determined from the mass balance during polymerization.

[0060] The mass ratio XII of polymer (II) to the final polymer may be calculated from the following formula using the heat of crystalline fusion of polymer (I) and the final polymer, respectively. XII=1-(ΔHf)T / (ΔHf)P In the above formula, (ΔHf)T: Heat of fusion of the final polymer (polymer (I) and polymer (II)) (unit: cal / g) (ΔHf)P: Heat of fusion of polymer (I) (unit: cal / g)

[0061] The molecular weight distribution (Mw / Mn) of the polymer (I) measured by GPC is preferably 3 or more and less than 7, and more preferably 3-5.

[0062] The polypropylene-based polymer (A) used in the present invention may contain one or more biomass-derived monomers. The same type of monomer constituting the polymer may be only biomass-derived monomers, or may contain both biomass-derived monomers and fossil fuel-derived monomers. The biomass-derived monomer is a monomer obtained from any renewable natural raw material or its residue, such as a plant-derived or animal-derived material, including fungi, yeast, algae, and bacteria, and contains, as carbon, 14 C isotope 10 -12 The biomass-derived monomer is contained in a proportion of about 100 (pMC) as measured in accordance with ASTM D 6866. The biomass-derived monomer can be obtained by a conventionally known method. It is preferable that the polypropylene-based polymer (A) used in the present invention contains a biomass-derived monomer from the viewpoint of reducing the environmental load. If the polymer production conditions such as the polymerization catalyst and polymerization temperature are the same, even if the raw material olefin contains a biomass-derived olefin, 14 C isotope 10 -12 Other than the proportion of propylene in the polymer, its molecular structure is the same as that of polypropylene polymers made from fossil fuel-derived monomers, and its performance is therefore said to be the same.

[0063] The polypropylene polymer (A) according to the present invention may also contain a chemically recycled monomer. The propylene constituting the polymer may consist solely of a chemically recycled monomer, or may contain a chemically recycled monomer together with a fossil fuel-derived monomer and / or a biomass-derived monomer. The chemically recycled monomer can be obtained by a conventionally known method. It is preferable that the polypropylene polymer (A) according to the present invention contains a chemically recycled monomer from the viewpoint of reducing the environmental load (mainly reducing waste). Even if the raw material monomer contains a chemically recycled monomer, the chemically recycled monomer is a monomer obtained by depolymerizing or pyrolyzing a polymer such as waste plastic back into a monomer unit such as propylene, or a monomer produced using such a monomer as a raw material. Therefore, if the polymer production conditions, such as the polymerization catalyst, polymerization process, and polymerization temperature, are equivalent, the molecular structure of the polypropylene polymer is equivalent to that of a fossil fuel-derived monomer. Therefore, the performance is also considered to be the same.

[0064] The polypropylene polymer (A) may be modified, but is preferably an unmodified polypropylene polymer that is not modified with at least an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative. The unsaturated carboxylic acid and unsaturated carboxylic acid derivative are the same as those described for the acid-modified polyolefin polymer (D). In the present invention, the term "unmodified polypropylene polymer (A)" does not necessarily mean an embodiment in which the total content of unsaturated carboxylic acid units and unsaturated carboxylic acid derivative units in 100% by mass of the polypropylene polymer (A) is 0% by mass, but also includes an embodiment in which the total content is more than 0% by mass and less than 0.1% by mass.

[0065] <Content of Polypropylene Polymer (A)> The content of the polypropylene polymer (A) in the polypropylene resin composition is preferably 25% by mass or more, more preferably 30% by mass or more, even more preferably 35% by mass or more, and preferably 70% by mass or less, more preferably 65% ​​by mass or less, even more preferably 60% by mass or less, based on 100% by mass of the total amount of the polypropylene resin composition.

[0066] [Flame retardant (B)] The polypropylene resin composition of the present invention contains a flame retardant (B). The polypropylene resin composition of the present invention may contain one type of flame retardant alone or two or more types in any combination in any ratio.

[0067] Examples of the flame retardant include halogen-based flame retardants, guanidine-based flame retardants, phosphorus-containing flame retardants, metal oxides, and polyvalent hydroxyl group-containing compounds, with phosphorus-containing flame retardants being preferred.

[0068] Examples of halogen-based flame retardants include organic halogenated aromatic compounds, such as halogenated diphenyl compounds, halogenated bisphenol compounds, halogenated bisphenol bis(alkyl ether) compounds, and halogenated phthalimide compounds.

[0069] Examples of halogenated diphenyl compounds include halogenated diphenyl ether compounds, halogenated diphenyl ketone compounds, and halogenated diphenyl alkane compounds.

[0070] Examples of halogenated bisphenol compounds include halogenated bisphenylalkanes, halogenated bisphenylethers, halogenated bisphenylthioethers, and halogenated bisphenylsulfones.

[0071] Examples of halogenated bisphenol bis(alkyl ether) compounds include brominated bisphenol A (brominated aliphatic ether), brominated bisphenol S (brominated aliphatic ether), chlorinated bisphenol A (chlorinated aliphatic ether), and chlorinated bisphenol S (chlorinated aliphatic ether), and further include etherified tetrabromobisphenol A and etherified tetrabromobisphenol S.

[0072] Examples of guanidine-based flame retardants include guanidine compounds such as guanidine nitride.

[0073] The phosphorus-containing flame retardant is a flame retardant containing a phosphorus atom. The polypropylene resin composition of the present invention preferably contains a phosphorus-containing flame retardant. The polypropylene resin composition of the present invention may contain one type of phosphorus-containing flame retardant alone or two or more types in any combination in any ratio.

[0074] Phosphorus-containing flame retardants include, for example, phosphates, polyphosphates, and phosphoric acid esters.

[0075] Examples of phosphates include melamine orthophosphate, piperazine orthophosphate, melamine pyrophosphate, piperazine pyrophosphate, calcium phosphate, and magnesium phosphate.Specific examples of polyphosphates include ammonium polyphosphate, piperazine polyphosphate, and melamine polyphosphate.

[0076] Examples of phosphates and polyphosphates include salts of orthophosphoric acid and the bases listed below, salts of pyrophosphoric acid and the bases listed below, and salts of polyphosphoric acid and the bases listed below. Examples of the base that can be contained in the phosphate salt include N,N,N',N'-tetramethyldiaminomethane, ethylenediamine, N,N'-dimethylethylenediamine, N,N'-diethylethylenediamine, N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N,N',N'-tetramethylethylenediamine, N,N'-diethylethylenediamine, 1,2-propanediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, trans-2,5-dimethylpiperazine, 1,4-bis(2-aminoethyl)piperazine, 1,4-bis(3-aminopropyl)piperazine, acetoguanamine, benzoguanamine, acrylguanamine, 2,4-diamino- 6-nonyl-1,3,5-triazine, 2,4-diamino-6-hydroxy-1,3,5-triazine, 2-amino-4,6-dihydroxy-1,3,5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino-6-ethoxy-1,3,5-triazine, 2,4-diamino-6-propoxy-1,3,5-triazine, 2,4-diamino-6-isopropoxy-1,3,5-triazine azine, 2,4-diamino-6-mercapto-1,3,5-triazine, 2-amino-4,6-dimercapto-1,3,5-triazine, ammeline, phthalodiguanamine, melamine cyanurate, butylenediguanamine, norbornenediguanamine, methylenediguanamine, ethylenedimelamine, trimethylenedimelamine, tetramethylenedimelamine, hexamethylenedimelamine, and 1,3-hexylenedimelamine.

[0077] The phosphorus-containing flame retardant is preferably one or more selected from the group consisting of melamine pyrophosphate, piperazine pyrophosphate, and ammonium polyphosphate.

[0078] In the present invention, among the phosphorus-containing flame retardants, intumescent flame retardants are preferred. An intumescent flame retardant is a substance that contains phosphorus and nitrogen as constituent components and that can impart flame retardancy to a molded article containing the intumescent flame retardant. When the molded article containing the intumescent flame retardant is burned, the molded article is heated by combustion and a foamed, expandable layer consisting of a foam-like coating is formed on the surface, thereby enabling the molded article to exhibit high flame retardancy. The intumescent flame retardant can also be said to be a substance that has the effect of forming a foamed, expandable layer consisting of a foam-like coating when a molded article containing the intumescent flame retardant is burned.

[0079] The intumescent flame retardant may be a compound containing both a phosphorus atom and a nitrogen atom in the molecule, a combination of a compound containing a phosphorus atom in the molecule with a compound containing a nitrogen atom in the molecule, or a combination of two or more of these. Among these, a compound containing both a phosphorus atom and a nitrogen atom in the molecule, or a combination of a compound containing a phosphorus atom in the molecule with a compound containing a nitrogen atom in the molecule is preferred in terms of exhibiting a high level of flame retardancy.

[0080] Examples of compounds containing both a phosphorus atom and a nitrogen atom in the molecule include those compounds described above as phosphorus-containing flame retardants, such as polyphosphates such as ammonium polyphosphate and melamine polyphosphate, phosphates such as melamine phosphate and phosphate ester amide, pyrophosphates such as piperazine pyrophosphate and melamine pyrophosphate, etc. These may be used alone or in combination of two or more.

[0081] In the case of a combination of a compound containing a phosphorus atom in its molecule and a compound containing a nitrogen atom in its molecule, examples of the compound containing a phosphorus atom include organic phosphorus compounds and red phosphorus. Examples of compounds containing a nitrogen atom in its molecule include hindered amines, melamine, ammonium borate, and ammonium carbonate. Among these, in terms of flame retardancy, organic phosphorus compounds are preferred as the compound containing a phosphorus atom, and hindered amines are preferred as the compound containing a nitrogen atom in its molecule. That is, the intumescent flame retardant preferably contains an organic phosphorus compound and a hindered amine, and more preferably contains only an organic phosphorus compound and a hindered amine. In addition, in the case of a combination of a compound containing a phosphorus atom in its molecule and a compound containing a nitrogen atom in its molecule, the term "compound containing a phosphorus atom" does not include compounds that contain a phosphorus atom and also a nitrogen atom, and the term "compound containing a nitrogen atom" does not include compounds that contain a nitrogen atom and also a phosphorus atom. Examples of the organic phosphorus compound include phosphonates, organic phosphites, organic phosphinites, metal salts of phosphinic acids, metal salts of diphosphinic acids, phosphinates, and polyol phosphate alcohols. Among these, phosphonates are preferred because they can provide foamed molded articles that are superior in ignition and non-ignition properties and self-extinguishing properties. Regarding intumescent flame retardants and organic phosphorus compounds, the contents of International Publication No. 2023 / 181879 can be referred to as appropriate, and the contents thereof are incorporated as is into this specification as part of its description.

[0082] The phosphorus-containing flame retardant and the intumescent flame retardant preferably contain both piperazine pyrophosphate and melamine pyrophosphate, and more preferably contain both piperazine pyrophosphate and melamine pyrophosphate, and the mass ratio of the content of melamine pyrophosphate to the content of piperazine pyrophosphate in the polypropylene resin composition of the present invention (melamine pyrophosphate / piperazine pyrophosphate) is preferably 0.25 or more and 1.0 or less.

[0083] The molar ratio of pyrophosphate to melamine in the melamine pyrophosphate salt is preferably 1:2. The molar ratio of pyrophosphate to piperazine in the piperazine pyrophosphate salt is preferably 1:1.

[0084] The melamine phosphate salts and melamine polyphosphate salts can be obtained by reacting the corresponding phosphoric acid or polyphosphoric acid or salts thereof with melamine, respectively. As the melamine pyrophosphate and the melamine polyphosphate, a melamine pyrophosphate and a melamine polyphosphate obtained by a method of thermally condensing monomelamine orthophosphate may be used, and the melamine pyrophosphate and the melamine polyphosphate obtained by these methods are preferred.

[0085] Piperazine phosphate salts and piperazine polyphosphate salts can be obtained by reacting the corresponding phosphoric acid or polyphosphoric acid or a salt thereof with piperazine, respectively. As the piperazine pyrophosphate and piperazine polyphosphate, those obtained by a method of thermally condensing monomelamine diorthophosphate may be used, and piperazine pyrophosphate and piperazine polyphosphate obtained by these methods are preferred.

[0086] Commercially available phosphates can also be used, such as "ADK STAB FP-2100J," "ADK STAB FP-2200S," "ADK STAB FP-2300S," and "ADK STAB FP-2500S" manufactured by ADEKA Corporation, "FCP-796" manufactured by Suzuhiro Chemical Co., Ltd., and "EXOLIT AP422" and "EXOLIT AP462" manufactured by Clariant Japan.

[0087] The phosphate esters include aromatic phosphate esters, aliphatic phosphate esters, and oligomers or polymers obtained from the aromatic phosphate esters and the aliphatic phosphate esters.

[0088] Examples of aromatic phosphate esters include trixylenyl phosphate, tris(phenyl) phosphate, trinaphthyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, resorcinol bis(diphenyl phosphate), resorcinol bis(dixylenyl phosphate), resorcinol bis(dicresyl phosphate), hydroquinone bis(dixylenyl phosphate), bisphenol A bis(diphenyl phosphate), and tetrakis(2,6-dimethylphenyl)1,3-phenylene bisphosphate.

[0089] Aliphatic phosphate esters include, for example, trimethyl phosphate, tributyl phosphate, tri(2-ethylhexyl) phosphate, tributoxyethyl phosphate, monoisodecyl phosphate, and 2-acryloyloxyethyl acid phosphate.

[0090] Commercially available phosphate esters can be used, such as "ADK STAB FP-600" and "ADK STAB FP-800" manufactured by ADEKA Corporation.

[0091] Examples of metal oxides include zinc oxide, magnesium oxide, calcium oxide, silicon dioxide, titanium oxide, manganese oxide (MnO, MnO), iron oxide (FeO, FeO, FeO), copper oxide, nickel oxide, tin oxide, aluminum oxide, and calcium aluminate. Preferred metal oxides are zinc oxide, magnesium oxide, and calcium oxide, with zinc oxide being more preferred.

[0092] The metal oxide may be surface-treated. Commercially available zinc oxide includes Type 2 zinc oxide manufactured by Seido Chemical Industry Co., Ltd., Type 1 zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd., partially coated zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd., Nanofine 50 (ultrafine zinc oxide particles having an average particle size of 0.02 μm: manufactured by Sakai Chemical Industry Co., Ltd.), and Nanofine K (ultrafine zinc oxide particles having an average particle size of 0.02 μm and coated with zinc silicate: manufactured by Sakai Chemical Industry Co., Ltd.).

[0093] A polyhydroxyl group-containing compound is a compound having two or more hydroxyl groups. Examples of polyhydroxyl group-containing compounds include pentaerythritol, dipentaerythritol, tripentaerythritol, polypentaerythritol having a condensation degree of 4 or more, trishydroxyethyl isocyanate, polyethylene glycol, glycerin, starch, glucose, cellulose, and sorbitol. As the polyhydroxyl group-containing compound, polyhydric alcohol compounds are preferred because of their low water solubility and low hygroscopicity, with pentaerythritol, dipentaerythritol, tripentaerythritol, or polypentaerythritol being more preferred, and pentaerythritol being even more preferred.

[0094] <Flame retardant (B) content> The content of the flame retardant (B) in the polypropylene resin composition of the present invention is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 45% by mass or less, even more preferably 40% by mass or less, based on 100% by mass of the total amount of the polypropylene resin composition.

[0095] When the polypropylene resin composition of the present invention contains a phosphorus-containing flame retardant, the content of flame retardants other than the phosphorus-containing flame retardant that can be contained in the polypropylene resin composition of the present invention is preferably 0 to 30 mass%, more preferably 0 to 20 mass%, even more preferably 0 to 10 mass%, and may be 0 mass%, relative to the total amount of the polypropylene resin composition of the present invention being 100 mass%.

[0096] Fiber The polypropylene resin composition of the present invention contains fibers (C). The polypropylene resin composition of the present invention may contain one type of fiber alone or two or more types of fibers in any combination in any ratio. Fiber (C) can be any fiber used as a reinforcing fiber for a resin molded article, without any particular limitation. Examples of fiber (C) include inorganic and organic fibers. Examples of inorganic fibers include fibrous magnesium oxysulfate, potassium titanate fiber, magnesium hydroxide fiber, aluminum borate fiber, calcium silicate fiber, calcium carbonate fiber, carbon fiber, glass fiber, metal fiber, asbestos fiber, graphite fiber, wollastonite, sepiolite, slag fiber, zonolite, elestadite, gypsum fiber, silica fiber, silica-alumina fiber, boron nitride fiber, silicon nitride fiber, and boron fiber. Examples of organic fibers include polyester fiber, nylon fiber, acrylic fiber, regenerated cellulose fiber, acetate fiber, kenaf, ramie, cotton, jute, hemp, sisal, flax, linen, silk, Manila hemp, sugarcane, wood pulp, wastepaper, recycled paper, and wool. As the fiber (C), inorganic fiber is preferred, and glass fiber is more preferred.

[0097] The material of the glass fiber is not particularly limited, and any glass can be used. Examples of the glass fiber material include E glass (alkali-free glass), A glass, C glass, S glass, and D glass, with E glass being preferred. Glass fibers manufactured by any manufacturing method can be used.

[0098] The glass fibers may be treated with a sizing agent and / or a surface treatment agent.

[0099] The glass fibers are preferably surface-treated with a surface treatment agent from the viewpoint of improving dispersibility in the polypropylene polymer (A), etc. Examples of the surface treatment agent include organic silane coupling agents, titanate coupling agents, aluminate coupling agents, zirconate coupling agents, silicone compounds, higher fatty acids, higher fatty acid metal salts, and fatty acid esters.

[0100] Examples of organic silane coupling agents include vinyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, and 3-acryloxypropyltrimethoxysilane.

[0101] Titanate coupling agents include, for example, isopropyl triisostearoyl titanate, isopropyl tris(dioctylpyrophosphate) titanate, and isopropyl tri(N-aminoethyl) titanate.

[0102] An example of an aluminate coupling agent is acetoalkoxyaluminum diisopropylate. Zirconate coupling agents include, for example, tetra(2,2-diallyloxymethyl)butyl, di(tridecyl)phosphite zirconate, and neopentyl(diallyl)oxytrineodecanoyl zirconate. Examples of the silicone compound include silicone oil and silicone resin.

[0103] Examples of higher fatty acids include oleic acid, capric acid, lauric acid, palmitic acid, stearic acid, montanic acid, linoleic acid, rosin acid, linolenic acid, undecanoic acid, and undecenoic acid.

[0104] Examples of higher fatty acid metal salts include sodium salts, lithium salts, calcium salts, magnesium salts, zinc salts, and aluminum salts of fatty acids having 9 or more carbon atoms (e.g., stearic acid, montanic acid). Of these, calcium stearate, aluminum stearate, calcium montanate, and sodium montanate are preferred.

[0105] Examples of fatty acid esters include polyhydric alcohol fatty acid esters such as glycerin fatty acid esters, alpha sulfo fatty acid esters, polyoxyethylene sorbitan fatty acid esters, sorbitan fatty acid esters, polyethylene fatty acid esters, and sucrose fatty acid esters.

[0106] The amount of the surface treatment agent used is not particularly limited, and is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the glass fibers.

[0107] Glass fibers treated with a sizing agent are bundled together. Examples of sizing agents include epoxy-based sizing agents, aromatic urethane-based sizing agents, aliphatic urethane-based sizing agents, acrylic-based sizing agents, and maleic anhydride-modified polyolefin-based sizing agents. The sizing agent is preferably one that melts at the temperature at which it is melted and kneaded with the polypropylene polymer (A), and more preferably one that melts at 200°C or lower.

[0108] The glass fiber may be a chopped strand obtained by cutting a glass strand (chopped glass fiber strand). From the viewpoint of further enhancing the effect of improving the rigidity and impact strength of a molded article containing a polypropylene-based resin composition, it is preferable to use a chopped strand glass fiber.

[0109] As the glass fibers, resin pellets containing glass fibers (glass fiber-containing resin pellets) may be used. In the glass fiber-containing pellets, the length of the glass fibers (fiber length) usually roughly matches the length of the resin pellets in the extrusion direction.

[0110] The glass fiber-containing resin pellets can be produced by any method. For example, glass fiber-containing resin pellets can be produced by a pultrusion molding method. The pultrusion molding method is a method in which, while drawing out a plurality of continuous glass fibers, a resin is melt-extruded from a resin extruder to impregnate the glass fiber bundles, thereby integrating the plurality of glass fiber bundles. The resin-impregnated glass fiber bundles are usually cooled and cut with a pelletizer to obtain glass fiber-containing resin pellets.

[0111] The content of glass fibers in the glass fiber-containing resin pellets is preferably 50 to 99.9% by mass.

[0112] As the glass fiber, commercially available products can be used.

[0113] <Physical properties and characteristics of fiber (C)> The cross-sectional area of ​​the fiber (C) is not particularly limited and can be set appropriately. However, in terms of rigidity and suppression of deformation of the molded product, it is preferable that the cross-sectional area is 2×10 -5 ~8×10 -3 mm 2 and more preferably 8×10 -5 ~8×10 -3 mm 2 and particularly preferably 8 × 10 -5 ~8×10 -4 mm 2 is.

[0114] The fiber (C) present in the polypropylene resin composition or molded article of the present invention usually has an aspect ratio of 20 to 60. The aspect ratio is preferably 25 or more, more preferably 30 or more, still more preferably 58 or less, and particularly preferably 55 or less.

[0115] The aspect ratio of the fiber (C) can be measured by the following method. 2 g of the polypropylene resin composition or molded article of the present invention is dissolved in boiling p-xylene for 2 hours to obtain a xylene-insoluble component containing fibers (C). The fibers (C) in the xylene-insoluble component are then observed using a microscope, and the lengths and diameters of 200 fibers (C) are measured. The weight-average fiber length and average fiber diameter of the 200 fibers (C) are calculated, and the ratio of the weight-average fiber length to the average fiber diameter is defined as the aspect ratio of the fibers (C) contained in the polypropylene resin composition or molded article of the present invention. Here, the weight average fiber length can be calculated according to the following formula. Weight average fiber length (Lw) = (Σqi × Li 2 ) / (Σqi×Li) In the above formula, Li is the length of the glass fiber (fiber length), and qi is the number of glass fibers having the fiber length Li. For flat fibers described later, the aspect ratio is calculated from the ratio of the weight average fiber length to the average fiber diameter of the "long diameter" of the fiber diameters.

[0116] Methods for adjusting the aspect ratio of the fiber (C) contained in the polypropylene-based resin composition or molded article of the present invention to fall within the above-mentioned range include appropriately adjusting the feed position of the fiber (C) into the extruder, the extruder temperature, the screw rotation speed, the melt flow rate of the polypropylene-based polymer used as the raw material, and the length (fiber length) and fiber diameter of the raw material fiber (C) when kneading the raw materials in the extruder. A specific preparation method is the method described in Patent Document 1. In this specification, the contents of Patent Document 1 can be referred to as appropriate, and the contents thereof are incorporated as is into this specification as part of the description thereof. For example, increasing the extruder temperature during production of the polypropylene resin composition of the present invention usually increases the aspect ratio and fiber length, and increasing the melt flow rate of the polypropylene polymer (A) used as the raw material usually increases the aspect ratio and fiber length.

[0117] The length (fiber length) of the fibers (C) present in the polypropylene resin composition or molded article of the present invention is preferably 200 μm or more, more preferably 300 μm or more, preferably 1000 μm, more preferably 900 μm or less, and even more preferably 800 μm or less, as a weight average fiber length based on 200 fibers. The length of the fibers (C) can be measured by observation with a microscope. The above-mentioned aspect ratio adjustment method can be used as a method for adjusting the fiber length.

[0118] The fibers (C) preferably contain flat fibers having a flat cross-sectional shape in which the ratio of the long diameter to the short diameter in the cross section [long diameter / short diameter] is 2.0 or more, and are preferably flat fibers having a flat cross-sectional shape in which the ratio of the long diameter to the short diameter in the cross section [long diameter / short diameter] is 2.0 or more. The flat cross-sectional shape is a flat cross-section in which, in a cross-section intersecting the axis of the fiber (C), typically a vertical cross-section, the ratio [longitudinal diameter / minor diameter] of the major diameter (the maximum length in the longitudinal direction of the cross-section, i.e., the maximum height of the cross-section when the flat fibers are arranged so that the major diameter is vertical) to the minor diameter (the maximum length in the lateral direction of the cross-section, i.e., the maximum width of the cross-section when the flat fibers are arranged so that the major diameter is horizontal) is 2.0 or more. This ratio [longitudinal diameter / minor diameter] indicates the flatness ratio (flattening rate) of the flat cross-sectional shape of the flat fiber, and the closer this ratio [longitudinal diameter / minor diameter] is to 1.0, the more circular the flat cross-sectional shape becomes. By containing flat fibers having a flat cross-sectional shape with the ratio [longitudinal diameter / minor diameter] of 2.0 or more, melt dripping due to flame contact can be suppressed, and even if melt dripping occurs, the amount of deformation can be homogenized, allowing the amount of deformation of the molded product to be adjusted to a constant level. Furthermore, the amount of deformation caused by the anisotropic orientation of the fibers can be homogenized and adjusted to an equal level. The ratio (major axis / minor axis) is preferably 2.5 or more, since deformation of the molded body can be highly suppressed and the amount of deformation can be adjusted to a smaller, but equivalent, level. On the other hand, the upper limit of the ratio (major axis / minor axis) is not particularly limited and can be 8.0 or less, but is preferably 5.0 or less, more preferably 4.5 or less, since the strength of the flat fibers can be ensured and the rigidity and thermal deformation of the molded body can be suppressed.

[0119] The ratio of the major axis to the minor axis in the cross section (flat cross-sectional shape) of a single flat fiber [major axis / minor axis] (also referred to in the present invention as "flat fiber ratio [major axis / minor axis]") can be determined by observing any flat cross section of the fiber under a microscope, measuring the minor axis and major axis, and dividing the major axis by the minor axis. In the present invention, the ratio of the major axis to the minor axis in the cross section of a flat fiber [major axis / minor axis] is determined by measuring a plurality of flat fibers, for example, 10 flat fibers, and calculating the arithmetic average of the ratios of the major axis to the minor axis in the cross section [major axis / minor axis] for each flat fiber.

[0120] The major axis of the flat fiber obtained as described above is not particularly limited, but may be, for example, 10 to 30 μm, and preferably 15 to 25 μm. The minor axis of the flat fiber obtained as described above is not particularly limited, but may be, for example, 3 to 10 μm, and preferably 4 to 8 μm.

[0121] The flat cross-sectional shape can be a shape obtained by squeezing a circular cross-section in one diameter direction, and examples thereof include an (approximately) rectangle, an (approximately) oval shape with the four corners of a rectangle chamfered, an ellipse, and a shape with a constricted center (cocoon shape). An (approximately) rectangle or an (approximately) oval shape are preferred. In the present invention, the above-mentioned shapes such as a cocoon shape that indicate the cross-sectional shape include not only geometrically accurate shapes but also shapes that are partially deformed as long as the above shape is maintained overall. The cross-section of the flat fiber used to calculate the ratio [major axis / minor axis] may be a cross-section obtained by cutting the flat fiber (removed from the molded product), or may be a cross-section of the flat fiber that appears on the cross-section of the molded product. In the present invention, when commercially available flat fibers are used in preparing the polypropylene resin composition of the present invention, the ratio of the major axis to the minor axis in the cross section of the flat fiber [major axis / minor axis] may be calculated as described above, or a catalog value may be used.

[0122] Flat fibers can be produced, for example, by spinning using a nozzle having an appropriate hole shape, such as an oval, cocoon-shaped, elliptical, or rectangular slit-shaped, as a bushing used to discharge the molten material. They can also be produced by spinning the molten material from multiple nozzles arranged close to each other and having various cross-sectional shapes (including circular cross-sections), and then bonding the spun molten filaments together to form a single filament. For such production techniques, see, for example, Japanese Patent Application Laid-Open Nos. 7-291649 and 2000-344541, the contents of which are incorporated herein by reference.

[0123] The fibers (C) may contain two or more types of flat fibers. The content (mass proportion) of the flat fibers contained in the fibers (C) is not particularly limited, and can be more than 0 mass% to 100 mass% or less, based on 100 mass% of the total mass of the fibers (C). In order to keep the deformation amount of the molded body at the same level overall, the content is preferably 20 mass% or more, more preferably 30 mass% or more, and particularly preferably 50 mass% or more. The upper limit of the content can be 98 mass% or less, or can be 90 mass% or less.

[0124] <Fiber (C) content> The content of the fibers (C) in the polypropylene resin composition of the present invention is not particularly limited, but in terms of increasing the rigidity of the molded body and suppressing the amount of deformation, the content is preferably 5% by mass or more, more preferably 8% by mass or more, even more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 46% by mass or less, and even more preferably 40% by mass or less, based on 100% by mass of the total amount of the polypropylene resin composition.

[0125] [Acid-modified polyolefin polymer (D)] The polypropylene resin composition of the present invention may contain an acid-modified polyolefin polymer (D) in addition to the polypropylene polymer (A), the flame retardant (B), and the fibers (C). When the polypropylene resin composition of the present invention contains the acid-modified polyolefin polymer (D), the compatibility between the polypropylene polymer (A) and the fibers (C) can be improved when the composition is molded into a molded article, thereby enhancing rigidity and highly suppressing deformation due to melt dripping caused by flame contact and deformation due to anisotropic fiber orientation.

[0126] In the present invention, the acid-modified polyolefin polymer means a polymer obtained by modifying a polyolefin polymer with an unsaturated carboxylic acid and / or an unsaturated carboxylic acid derivative. Examples of the acid-modified polyolefin polymer include an acid-modified polyethylene polymer and an acid-modified polypropylene polymer. The acid-modified polyethylene polymer means a polymer obtained by modifying a polyethylene polymer with an unsaturated carboxylic acid and / or an unsaturated carboxylic acid derivative. The acid-modified polypropylene polymer means a polymer obtained by modifying a polypropylene polymer with an unsaturated carboxylic acid and / or an unsaturated carboxylic acid derivative. The polyolefin polymer to be modified is a homopolymer of one type of olefin or a copolymer of two or more types of olefins. Examples of the polyolefin polymer to be modified include polyethylene polymers and polypropylene polymers. The polyethylene polymer to be modified is a polymer containing ethylene units in an amount of more than 50% by mass based on the total structural units of the polymer, and the amount of ethylene units in the polyethylene polymer is usually 100% by mass or less.

[0127] The polypropylene polymer to be modified is a polymer containing propylene units in an amount of more than 50% by mass based on the total structural units of the polymer, and the amount of propylene units in the polypropylene polymer is usually 100% by mass or less. Examples of the polypropylene polymer to be acid-modified include the examples and preferred examples shown as the polypropylene polymer (A).

[0128] Acid-modified polypropylene polymers are generally polymers having a partial structure of a polypropylene polymer and a partial structure derived from an unsaturated carboxylic acid and / or an unsaturated carboxylic acid derivative. Examples of acid-modified polypropylene polymers include (a) polymers obtained by graft polymerizing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid derivative onto a propylene homopolymer, (b) polymers obtained by graft polymerizing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid derivative onto a copolymer obtained by copolymerizing propylene with one or more other monomers selected from the group consisting of ethylene and α-olefins having 4 or more carbon atoms, and (c) modified polypropylene polymers obtained by graft polymerizing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid derivative onto a block copolymer obtained by homopolymerizing propylene and then copolymerizing it with one or more other monomers selected from the group consisting of ethylene and α-olefins having 4 or more carbon atoms.

[0129] The acid-modified polypropylene polymer to be subjected to acid modification may be a single polymer or a combination of two or more polymers in any ratio. Therefore, the acid-modified polypropylene polymer to be subjected to acid modification may be the heterophasic propylene polymer material described above.

[0130] Examples of the unsaturated carboxylic acid include maleic acid, fumaric acid, itaconic acid, acrylic acid, and methacrylic acid.

[0131] Examples of the unsaturated carboxylic acid derivatives include unsaturated carboxylic acid anhydrides, ester compounds, amide compounds, imide compounds, and metal salts. Examples of the unsaturated carboxylic acid derivatives include maleic anhydride, itaconic anhydride, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-hydroxyethyl methacrylate, maleic acid monoethyl ester, maleic acid diethyl ester, fumaric acid monomethyl ester, fumaric acid dimethyl ester, acrylamide, methacrylamide, maleic acid monoamide, maleic acid diamide, fumaric acid monoamide, maleimide, N-butylmaleimide, and sodium methacrylate.

[0132] As the unsaturated carboxylic acid, for example, maleic acid and acrylic acid are preferred, and as the unsaturated carboxylic acid derivative, maleic anhydride and 2-hydroxyethyl methacrylate are preferred.

[0133] The acid-modified polypropylene polymer is preferably the polymer (b) or the polymer (c) described above. In the present invention, the acid-modified polypropylene polymer is preferably a modified polyolefin polymer obtained by graft polymerizing maleic anhydride onto a polyolefin polymer containing propylene units in an amount of more than 50 mass% of all constituent units.

[0134] The total content of unsaturated carboxylic acid units and unsaturated carboxylic acid derivative units in the acid-modified polyolefin polymer (also referred to as "graft ratio") is preferably 0.1 to 20 mass%, more preferably 0.1 to 10 mass%, based on 100 mass% of the amount of the acid-modified polyolefin polymer, from the viewpoint of the rigidity and hardness of a molded article obtained from the polypropylene resin composition of the present invention. When the acid-modified polyolefin polymer contains only one of unsaturated carboxylic acid units and unsaturated carboxylic acid derivative units, the total content refers to the content of only one unit.

[0135] The content of unsaturated carboxylic acid units and unsaturated carboxylic acid derivative units is a value calculated by quantifying the absorption due to unsaturated carboxylic acid and unsaturated carboxylic acid derivatives using infrared absorption spectroscopy or NMR spectroscopy.

[0136] The graft efficiency of the unsaturated carboxylic acid and / or unsaturated carboxylic acid derivative in the acid-modified polyolefin polymer is preferably 0.51 or more from the viewpoint of the rigidity and impact strength of the molded article obtained from the polypropylene resin composition of the present invention.

[0137] The "graft efficiency of an acid-modified polyolefin polymer" means the ratio of the amount of unsaturated carboxylic acid and / or unsaturated carboxylic acid derivative chemically bonded to the polymer to the total amount of unsaturated carboxylic acid and / or unsaturated carboxylic acid derivative chemically bonded to the polymer and unsaturated carboxylic acid and / or unsaturated carboxylic acid derivative not chemically bonded to the polymer, which are contained in the acid-modified polyolefin polymer. The graft efficiency in the graft polymerization of unsaturated carboxylic acid and / or unsaturated carboxylic acid derivative can be determined by the following steps (1) to (9).

[0138] (1) Dissolve 1.0 g of acid-modified polyolefin polymer in 100 ml of xylene. (2) The xylene solution is added dropwise to 1000 ml of methanol while stirring to reprecipitate the acid-modified polyolefin polymer. (3) recovering the reprecipitated acid-modified polyolefin polymer; (4) The recovered acid-modified polyolefin polymer is vacuum-dried at 80°C for 8 hours to obtain a purified acid-modified polyolefin polymer. (5) The purified acid-modified polyolefin polymer is heat-pressed to produce a film having a thickness of 100 μm. (6) measuring the infrared absorption spectrum of the film; (7) quantifying the absorption due to the unsaturated carboxylic acid and / or unsaturated carboxylic acid derivative from the infrared absorption spectrum, and calculating the content (X1) of the unsaturated carboxylic acid and / or unsaturated carboxylic acid derivative that has reacted with the polyolefin polymer in the acid-modified polyolefin polymer; (8) Separately, the above procedures (5) and (6) are carried out on an unpurified acid-modified polyolefin polymer, and the content (X2) of unsaturated carboxylic acid and / or unsaturated carboxylic acid derivative in the unpurified acid-modified polyolefin polymer is calculated from the infrared absorption spectrum (X2 is the sum of the content (X1) of unsaturated carboxylic acid and / or unsaturated carboxylic acid derivative reacted with the polypropylene polymer and the content (X1) of unsaturated carboxylic acid and / or unsaturated carboxylic acid derivative not reacted with the polyolefin polymer (i.e., free).), The grafting efficiency is calculated from the formula (9): Grafting efficiency = X1 / X2.

[0139] From the viewpoint of mechanical strength and production stability, the MFR of the acid-modified polypropylene polymer is preferably 5 to 400 g / 10 min, more preferably 10 to 200 g / 10 min, and particularly preferably 20 to 200 g / 10 min.

[0140] <Content of Acid-Modified Polypropylene Polymer (D)> The content of the acid-modified polypropylene polymer (D) in the polypropylene resin composition is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.5% by mass or more, and preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and even more preferably 2.5% by mass or less, based on 100% by mass of the total amount of the polypropylene resin composition.

[0141] [Other ingredients] The polypropylene resin composition of the present invention may contain, in addition to the components (A) to (D) already explained above, other components (hereinafter sometimes referred to as "other components") as further optional components. Examples of other components include elastomers, neutralizing agents, antioxidants, metal deactivators, UV absorbers, lubricants, antistatic agents, antiblocking agents, processing aids, organic peroxides, colorants (inorganic pigments, organic pigments, etc.), pigment dispersants, foaming agents, foam nucleating agents, plasticizers, crosslinking agents, crosslinking aids, brightness enhancers, antibacterial agents, light diffusing agents, and molecular weight modifiers. The polypropylene resin composition of the present invention may contain one type of other component alone, or two or more types in any combination in any ratio.

[0142] Examples of the elastomer include random copolymers having ethylene units and α-olefin units having 4 to 10 carbon atoms. The random copolymers preferably have an MFR of 0.1 to 50 g / 10 min.

[0143] Examples of the α-olefins having 4 to 10 carbon atoms that constitute the elastomer random copolymer include the same α-olefins having 4 to 10 carbon atoms that can constitute the polypropylene polymer (A), such as linear or branched α-olefins such as 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene, and cyclic α-olefins such as vinylcyclopropane and vinylcyclobutane, with 1-butene, 1-hexene, and 1-octene being preferred.

[0144] Examples of the random copolymer that is an elastomer include ethylene-1-butene random copolymer, ethylene-1-hexene random copolymer, ethylene-1-octene random copolymer, ethylene-1-decene random copolymer, ethylene-(3-methyl-1-butene) random copolymer, and copolymers of ethylene and an α-olefin having a cyclic structure.

[0145] The content of the α-olefin in the random copolymer is preferably 1 to 49% by mass, more preferably 5 to 49% by mass, and even more preferably 24 to 49% by mass, with the mass of the random copolymer being 100% by mass.

[0146] From the viewpoint of improving the impact resistance of a molded article containing the polypropylene-based resin composition of the present invention, the density of the random copolymer is preferably 0.850 to 0.890 g / cm. 3 and more preferably 0.850 to 0.880 g / cm 3 and more preferably 0.855 to 0.867 g / cm 3 is.

[0147] The random copolymer, which is an elastomer, can be produced by polymerizing monomers using a polymerization catalyst, such as those listed above as polymerization catalysts for producing the polypropylene-based polymer.

[0148] The random copolymer may be a commercially available product, such as Engage (registered trademark) manufactured by Dow Chemical Japan, Tafmer (registered trademark) manufactured by Mitsui Chemicals, Inc., Neozex (registered trademark) and Ultozex (registered trademark) manufactured by Prime Polymer Co., Ltd., and Excellen FX (registered trademark), Sumikathene (registered trademark), and Esprene SPO (registered trademark) manufactured by Sumitomo Chemical Co., Ltd.

[0149] The content of the elastomer in the polypropylene resin composition of the present invention is preferably 0 to 30% by mass, more preferably 0 to 10% by mass, based on 100% by mass of the polypropylene resin composition of the present invention. In the present invention, the content of the elastomer in the polypropylene resin composition of the present invention may also be 5 to 30% by mass.

[0150] [Physical properties of polypropylene resin composition] The polypropylene resin composition of the present invention has a melt flow rate of preferably 0.1 g / 10 min or more, more preferably 1 g / 10 min or more, and preferably 400 g / 10 min or less, more preferably 300 g / 10 min or less, and even more preferably 200 g / 10 min or less. When the MFR of the polypropylene resin composition of the present invention is the upper limit value or less of the above range, the flame retardancy of the polypropylene resin composition of the present invention can be effectively improved, and when the MFR is the lower limit value or more of the above range, the weld strength of a molded article containing the polypropylene resin composition of the present invention can be improved.

[0151] In the present invention, the polypropylene resin composition of the present invention is not particularly limited in terms of its properties or form as long as it contains the polypropylene polymer (A), the flame retardant (B), and the fibers (C). It includes a mixture (melt-kneaded product) of the components, e.g., an unmolded product such as a strand or pellet, as well as a molded product. The shape of the pellets is not particularly limited, and examples thereof include granules and tablets. For example, a pellet-like pellet can be produced by preparing a strand-like propylene resin composition and then cutting it to an appropriate length. In the present invention, the term "unmolded product" refers to a product that is not molded into a shape or size suitable for various applications and is used as a molding material, and the term "molded product" refers to a product molded into a shape or size suitable for various applications.

[0152] [Method of producing polypropylene resin composition] The polypropylene resin composition of the present invention can be produced by known methods, and can usually be produced by melt-kneading the components already described. The order in which the components are kneaded is not particularly limited. For example, all components may be charged into a melt-kneading device at once and kneaded, or a mixture obtained by kneading some of the components may be kneaded with the remaining components. Here, the kneading method and timing of the fibers (C) are not particularly limited, but the kneading method and timing described in the preferred production method below are preferred.

[0153] The melt-kneading temperature is not particularly limited and may be determined appropriately. The melt-kneading temperature is usually preferably 170° C. or higher, more preferably 180° C. or higher, and even more preferably 200° C. or higher, and preferably 250° C. or lower. The melt-kneading time is also not particularly limited and may be determined appropriately.

[0154] A conventionally known melt-kneading apparatus can be used as the melt-kneading apparatus for melt-kneading to produce the polypropylene resin composition of the present invention, and suitable melt-kneading apparatuses include, for example, a Banbury mixer, a single-screw extruder, a twin-screw co-rotating extruder, and a twin-screw counter-rotating extruder. Examples of melt-kneading apparatuses include ZSK (registered trademark) manufactured by Coperion, TEM (registered trademark) manufactured by Toshiba Machine Co., Ltd., TEX (registered trademark) manufactured by The Japan Steel Works, Ltd., KZW (registered trademark) manufactured by Technovel Co., Ltd., CMP (registered trademark) and TEX (registered trademark) manufactured by The Japan Steel Works, Ltd., and FCM (registered trademark), NCM (registered trademark), and LCM (registered trademark) manufactured by Kobe Steel, Ltd.

[0155] A preferred method for producing the polypropylene resin composition of the present invention includes melt-kneading a raw material (1) containing a polypropylene polymer (A) and a flame retardant (B) into the cylinder of a twin-screw kneading extruder equipped with a cylinder and two screws, at a distance L1 from the upstream ends of the two screws, and a fiber (C) into the cylinder at a distance L2 from the upstream ends of the two screws. Here, L1 / L is preferably 0 or more and less than 0.3, and L2 / L is preferably 0.3 to 0.9, more preferably 0.5 or more, even more preferably 0.6 or more, particularly preferably 0.5 to 0.9, and most preferably 0.6 to 0.9. Generally, decreasing L2 / L reduces the aspect ratio of the fiber (C) contained in the polypropylene resin composition of the present invention, while increasing L2 / L increases the aspect ratio. Here, L is the length of the screw from the upstream end to the downstream end in the direction of the resin flow being kneaded (i.e., the total length of the screw). The above-mentioned preferred production method is particularly suitably employed when producing a polypropylene-based resin composition containing glass fibers as the fibers (C).

[0156] The raw material (1) may contain, as an optional component, a molecular weight modifier for adjusting the molecular weight of the polypropylene polymer. Examples of the molecular weight modifier include organic peroxides. The molecular weight modifier may be contained in the raw material (1) in the form of a masterbatch diluted with an optional resin.

[0157] The polypropylene resin composition of the present invention is suitable as a material for forming a molded article, particularly a molded article that can achieve excellent flame retardancy and an equivalent level of deformation, and in terms of molding method, is suitable as a material for forming an injection-molded article.

[0158] [[Molded body]] The molded article of the present invention is a molded article containing the polypropylene resin composition of the present invention. The molded article of the present invention is a molded article obtained by molding a melt-kneaded product of the above-mentioned components or the polypropylene resin composition of the present invention by a known molding method.

[0159] The polypropylene resin composition of the present invention contained in the molded article is the same as that explained above in [Polypropylene Resin Composition of the Present Invention].

[0160] Molded articles can be obtained simultaneously with or consecutively to the preparation (melt-kneading) of the polypropylene-based resin composition of the present invention. Alternatively, after preparing the polypropylene-based resin composition of the present invention, the polypropylene-based resin composition can be molded by various molding methods. The molding method is not particularly limited, and known molding methods can be applied, such as injection molding, extrusion molding, compression molding, profile molding, vacuum molding, sheet molding, roll molding, hot press molding, foam molding, injection press molding, blow molding, and gas injection molding. Injection molding is preferred. In addition to general injection molding, injection foam molding, supercritical injection foam molding, ultra-high speed injection molding, injection compression molding, gas-assisted injection molding, sandwich molding, sandwich foam molding, and insert-outsert molding can also be applied. The molded article of the present invention is preferably an injection-molded article molded by injection molding.

[0161] The molding conditions for each molding method are not particularly limited as long as the melt-kneaded mixture of the above-mentioned components or the polypropylene resin composition of the present invention can be molded in a molten state, and can be appropriately set depending on the composition and physical properties of the melt-kneaded mixture of the above-mentioned components or the polypropylene resin composition of the present invention. The kneading method and kneading conditions (kneading temperature) used in preparing the polypropylene resin composition of the present invention can be preferably applied. The shape and size of the molded article of the present invention are determined appropriately depending on the intended use. For example, the outer dimensions of the molded article are 0.5 to 2 m in length, 0.5 to 2 m in width, and 1 to 10 mm in thickness. The shape of the molded article is determined appropriately depending on the intended use, and may be, for example, a plate or hollow shape.

[0162] The molded article of the present invention may be a molded article consisting solely of a molded article of the polypropylene resin composition of the present invention, or may be a molded article consisting of the molded article and other members. Examples of other members include a surface layer (coating layer), a colored layer, a reinforcing layer, etc. Furthermore, the molded article of the present invention may be subjected to a surface treatment such as a hard coat, a water-repellent treatment, or an antibacterial treatment, as necessary.

[0163] The molded article of the present invention contains the polypropylene resin composition of the present invention, has excellent flame retardancy, and even if it deforms due to flame contact and melt drips, the amount of deformation can be kept small and at a constant level (even when exposed to flame, the deformation is small and at a constant level overall). Preferably, the molded article of the present invention can also maintain the amount of deformation of the molded article caused by the anisotropic arrangement of the fibers (C) at a constant level overall.

[0164] The molded article of the present invention is a molded article (particularly an injection molded article) that has excellent flame retardancy and exhibits a small amount of deformation at the same level. Examples of the molded article include injection molded articles, extrusion molded articles, compression molded articles, irregular molded articles, vacuum molded articles, sheet molded articles, roll molded articles, heat press molded articles, foam molded articles, injection press molded articles, blow molded articles, and gas injection molded articles. The molded article of the present invention can be suitably used as various components (for example, automobile interior / exterior parts and engine room interior parts, motorcycle parts, electrical appliance parts, various containers, and furniture). Examples of automobile interior / exterior parts include instrument panels, door trims, pillars, side protectors, console boxes, column covers, bumpers, fenders, and wheel covers. Examples of automobile engine room interior parts include battery cases and engine covers. Examples of motorcycle parts include cowlings and muffler covers. [Example]

[0165] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these examples.

[0166] In the following description, the units "%" and "parts" that represent amounts are by mass unless otherwise specified. Furthermore, the operations described below were carried out under normal temperature and pressure conditions unless otherwise specified.

[0167] The components used in the examples and comparative examples are shown below. (1) Polypropylene polymer (A) Using the polymerization catalyst obtained by the method described in Example 1 of JP-A No. 2004-182981, propylene homopolymers were produced by gas phase polymerization under conditions such that polypropylene-based polymers having the following physical properties were obtained. (A-1) Propylene homopolymer MFR: (230℃, load 2.16kgf): 18g / 10min (A-2) Propylene homopolymer MFR: (230℃, load 2.16kgf): 120g / 10min

[0168] (A-3) Heterophagic propylene polymer material Using the polymerization catalyst obtained by the method described in Example 1 of JP 2004-182981 A, a heterophasic propylene polymerization material (A-3) was produced as a polypropylene-based polymer (A) by a liquid-gas phase polymerization method, containing 79 parts by mass of (a) a propylene homopolymer component as polymer (I) and 21 parts by mass of (b) a propylene-ethylene random copolymer component as polymer (II). The physical properties were as follows: Melt flow rate (230°C, load 2.16 kgf): 60 g / 10 min (a) Propylene homopolymer component Intrinsic viscosity: 1.06dL / g (b) Propylene-ethylene random copolymer Intrinsic viscosity: 2.8dL / g Content of structural units derived from ethylene: 33% by mass

[0169] (b) The content of ethylene-derived structural units in the propylene-ethylene random copolymer was measured under the following conditions: 13 The values ​​were determined from the C-NMR spectrum based on the report by Kakugo et al. (Macromolecules, 15, 1150-1152 (1982)). 13The C-NMR spectrum was measured under the following conditions using a sample prepared by uniformly dissolving about 200 mg of the heterophasic propylene polymerization material (A-3) in 3 mL of orthodichlorobenzene in a test tube with a diameter of 10 mm. Measurement temperature: 135℃ Pulse repetition time: 10 seconds Pulse width: 45° Accumulation count: 2500 times

[0170] (2) Flame retardant (B) The following flame retardants were prepared. (B-1) Flame retardant (intemescent flame retardant) Product name: ADK STAB FP-2500S (ADEKA) Main ingredients: melamine phosphate, piperazine phosphate (B-2) Flame retardant (intemescent flame retardant) Product name: ADK STAB FP-2300S (ADEKA) Main ingredients: melamine phosphate, piperazine phosphate (B-3) Flame retardant (intemescent flame retardant) Ammonium polyphosphate flame retardant Product name: HP-FR-8300 (manufactured by Xusen) Main ingredient: ammonium polyphosphate

[0171] (3) Fiber (C) The following fibers were prepared. Although (C-3) glass fiber, (C-4) glass flake, and (C-5) talc do not fall under the category of fiber (C), they are included in the category of fiber (C) in this example.

[0172] (C-1) Glass fiber (chopped strand) Product name: ESC03T-480FGF (Nippon Electric Glass Co., Ltd.) Long diameter: 20 μm (catalog value) Minor diameter: 5 μm (catalog value) Fiber length: 4mm (catalog value) Ratio of major axis to minor axis in cross section [major axis / minor axis] (flattening ratio): 4.0 (C-2) Glass fiber (chopped strand) Long diameter: 18 μm (catalog value) Minor diameter: 6 μm (catalog value) Fiber length: 4mm (catalog value) Ratio of major axis to minor axis in cross section [major axis / minor axis] (flattening ratio): 3.0 (C-3) Glass fiber (chopped strand) Product name: ESC03T-480H (manufactured by Nippon Electric Glass Co., Ltd.) Diameter: 10.5 μm (catalog value) Fiber length: 3.0 mm (catalog value) Ratio of major axis to minor axis in cross section [major axis / minor axis] (flattening ratio): 1.0

[0173] (C-4) Glass flakes Product name: MEG160FY-M04 (Nippon Electric Glass Co., Ltd.) Glass flakes with an average thickness of approximately 0.7 μm and an average particle size of approximately 160 μm (C-5) Talc Product name: UPN TT-K (manufactured by Hayashi Kasei Co., Ltd.)

[0174] (4) Acid-modified polyolefin polymer (D) As the acid-modified polyolefin polymer (D), maleic anhydride-modified polypropylene (hereinafter, sometimes referred to as "acid-modified PP") (D-1) was produced as follows. Specifically, 100 parts by mass of polypropylene resin powder (intrinsic viscosity [η] = 3.0 dl / g, ethylene content 0.2% by mass) was mixed with 1.0 part by mass of maleic anhydride, 0.14 part by mass of di-(tert-butylperoxy)diisopropylbenzene (product name: Perbutyl P, manufactured by NOF Corporation), 0.05 part by mass of dicetyl peroxydicarbonate (product name: Perkadox 24FL, manufactured by Kayaku Akzo Co., Ltd.), 0.05 part by mass of calcium stearate (product name: AR-2, manufactured by Sakai Chemical Industry Co., Ltd.), and 0.3 part by mass of the antioxidant pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (product name: Songnox 1010, manufactured by SONGWON Co., Ltd.), and the mixture was thoroughly premixed. The mixture was then fed into the feed port of a twin-screw extruder and kneaded to obtain acid-modified PP (D-1). The acid-modified PP obtained had an MFR (230°C, load 2.16 kgf) of 170 g / 10 min and a graft ratio of 0.32%.

[0175] [evaluation] The evaluation was carried out according to the test methods shown below. (flammability according to standard UL94-V) Each resin composition prepared in the Examples and Comparative Examples was fed into an injection molding machine, "IS100EN" manufactured by Toshiba Machine Co., Ltd., and injection molded under conditions of a molding temperature of 220°C and a mold cooling temperature of 50°C to produce a test plate measuring 160 mm (length) x 160 mm (width) x 2.0 mm (thickness). Test specimens measuring 127 mm (length) x 13 mm (width) x 2.0 mm (thickness) were cut in the MD direction from the resulting 2.0 mm thick test plate. The flame retardancy of the resulting test specimens was evaluated according to the UL94-V standard. The evaluation was based on the UL94-V standard, with a rating of "V-0" if it met the V-0 criteria, "V-1" if it met the V-1 criteria, "V-2" if it met the V-2 criteria, and "fail" if it did not meet the V-2 criteria. In terms of flame retardancy, V-0 is better than V-1, and V-1 is better than V-2.

[0176] (Melting and dripping (deformation) of the test piece due to combustion) Each resin composition prepared in the Examples and Comparative Examples was fed into an injection molding machine (Toshiba Machine Co., Ltd., IS100EN) and injection molded at a molding temperature of 220°C and a mold cooling temperature of 50°C to produce test plates measuring 160 mm (length) × 160 mm (width) × 2.0 mm (thickness). The resulting 2.0 mm-thick test plates were cut into 127 mm (length) × 13 mm (width) × 2.0 mm (thickness). Two test pieces were cut in the MD and TD directions, and two different test pieces were prepared for each resin composition. The MD direction was parallel to the flow direction of the resin composition during injection molding, and the TD direction was perpendicular to the flow direction of the resin composition during injection molding. The resulting test pieces were fixed horizontally to the ground, and a gas burner was used to flame the edge of the test piece for 20 seconds. The flame intensity was the same as that used in the UL94-V test, and the flame was applied perpendicular to the test piece. After the test, the length of the specimen hanging down in the vertical direction (the amount of deformation of the specimen end in the vertical direction from the fixed surface due to its own weight) was measured using a ruler. In addition, when the test piece was completely burned and the amount of deformation could not be measured, it was considered to be "completely burned."

[0177] [Example 1] A total of 100 parts by mass of 48.5 parts by mass of polypropylene (A-2), 1.5 parts by mass of modified PP (D-1), 20 parts by mass of flame retardant (B-1), and components (A-1), (D-1), (B-1), and (C-1) described below was mixed with 0.05 parts by mass of calcium stearate (product name: Calcium Stearate S, manufactured by Nippon Oil & Fats Co., Ltd.) as a neutralizing agent and 2,3-bis[[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazine (product name: Rianox MD-1024, manufactured by Lianglong Co., Ltd.) 0.2 parts by mass, tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate (product name: Irganox3114, manufactured by BASF) 0.2 parts by mass as an antioxidant, 3,9-bis(2,4-di-tert-butylphenoxy)-2,4,8,10-tetraoxaspiro[5·5]undecane (product name: Songnox6260, manufactured by SONGWON Co., Ltd.) 0.2 parts by mass, and distearyl-3,3-thiodipropionate (product name: The mixture was melt-kneaded with 0.25 parts by mass of a polypropylene-based resin (trade name: Sumilizer TPS, manufactured by Sumitomo Chemical Co., Ltd.) in a twin-screw kneading extruder at a temperature of 200 to 230°C and a screw rotation speed of 400 rpm, and 30 parts by mass of glass fiber (C-1) was side-fed into the extruder midway, specifically from a position about 70% (L2 / L=0.7) of the total screw length. The glass fiber (C-1) was passed through a cold water bath and then the strands were cut with a strand cutter to obtain pellets (corresponding to a polypropylene-based resin composition). The obtained pellets were dried in a hot air dryer at 100°C for 2 hours and then molded in each molding machine used in the above evaluation to produce injection molded articles.

[0178] [Examples 2 to 5 and Comparative Examples 1 to 6] Pellets of polypropylene resin compositions of Examples 2 to 5 and Comparative Examples 1 to 6 were obtained in the same manner as in Example 1, except that in Example 1, components (A) to (D) were changed to the components and contents shown in Tables 1 and 2, and injection-molded articles of Examples 2 to 5 and Comparative Examples 1 to 6 were produced.

[0179] Comparative Example 7 72 parts by mass of polypropylene (A-1), 28 parts by mass of flame retardant (B-1), and 100 parts by mass of a mixture thereof were mixed with 0.05 parts by mass of calcium stearate (product name: Calcium Stearate S, manufactured by Nippon Oil & Fats Co., Ltd.) as a neutralizing agent and 2,3-bis[[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazine (product name: Rianox) as a metal deactivator. 0.2 parts by mass of tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate (product name: Irganox 3114, manufactured by BASF) as an antioxidant, 0.2 parts by mass of 3,9-bis(2,4-di-tert-butylphenoxy)-2,4,8,10-tetraoxaspiro[5·5]undecane (product name: Songnox 6260, manufactured by SONGWON), and 0.25 parts by mass of distearyl-3,3-thiodipropionate (product name: Sumilizer TPS, manufactured by Sumitomo Chemical Co., Ltd.) were melt-kneaded in a twin-screw kneading extruder at a temperature of 200 to 230°C and a screw rotation speed of 400 rpm. The mixture was passed through a cold water bath and then strands were cut with a strand cutter to obtain pellets. The obtained pellets were dried in a hot air dryer at 100°C for 2 hours and then molded in each molding machine used in the above evaluation to produce injection molded articles.

[0180] [Comparative Examples 8 and 9] Pellets of the polypropylene resin compositions of Comparative Examples 8 and 9 were obtained and injection-molded articles of Comparative Examples 8 and 9 were produced in the same manner as in Comparative Example 7, except that in Comparative Example 7, components (A) and (B) were changed to the components and contents shown in Table 2, and components (C) and (D) were mixed in the contents shown in Table 2.

[0181] The resulting pellets of each polypropylene resin composition were evaluated for flammability according to the UL94-V standard and melting sagging of the test specimens during combustion using the evaluation methods described above. The results are shown in Tables 1 and 2. It was confirmed that the average fiber length of the fibers (C-1) and (C-2) present in each of the polypropylene resin compositions and injection molded articles of Examples 1 to 5 was in the range of 200 to 800 μm.

[0182] [Table 1]

[0183] [Table 2]

[0184] As is clear from the results shown in Tables 1 and 2, Comparative Examples 1 and 2, which do not contain flat fibers, contain glass fibers with a circular cross section, but the melting and dripping that occurs when test pieces cut in the TD direction burn is greater than the melting and dripping that occurs when test pieces cut in the MD direction burn, and they cannot achieve the same level of deformation. Furthermore, Comparative Examples 3 to 6, which contain flat fibers but no flame retardant, are inferior in flame retardancy, and all of them burned down in the test (for melting and dripping that occurs when test pieces burn). Comparative Example 7, which does not contain flat fibers, showed a large amount of deformation when exposed to flame, and Comparative Examples 8 and 9, which do not contain flat fibers, did not exhibit sufficient flame retardancy even though they contained talc or glass flakes, and all of them burned down in the test (for melting and dripping that occurs when test pieces burned). In contrast, Examples 1 to 5, which contain a polypropylene-based polymer, a flame retardant, and flat fibers with a ratio of the long diameter to the short diameter in the cross section [long diameter / short diameter] of 2.0 or more, can achieve a high level of flame retardancy of V-0, and can highly suppress the melt dripping caused by combustion of test pieces cut in the TD direction to a level equivalent to that of test pieces cut in the MD direction.This means that while exhibiting excellent flame retardancy, they can achieve molded articles with small overall deformation when exposed to flame and at a similar level.

Claims

1. A polypropylene-based resin composition comprising a polypropylene-based polymer (A), a flame retardant (B), and fibers (C), The polypropylene-based resin composition, wherein the fibers (C) have a flat cross-sectional shape in which the ratio of the major axis to the minor axis in the cross section [major axis / minor axis] is 2.0 or more.

2. The polypropylene resin composition according to claim 1, wherein the fiber (C) is a glass fiber.

3. The polypropylene resin composition according to claim 1, wherein the fibers (C) are chopped glass fiber strands.

4. 2. The polypropylene resin composition according to claim 1, wherein the weight average fiber length of the fibers (C) is 200 to 800 μm.

5. The polypropylene resin composition according to claim 1 , wherein the flame retardant (B) comprises a phosphorus-containing flame retardant.

6. The polypropylene resin composition according to claim 1, wherein the flame retardant (B) comprises an intumescent flame retardant.

7. When the total amount of the polypropylene resin composition is 100% by mass, The content of the polypropylene polymer (A) is 25 to 70% by mass, The content of the flame retardant (B) is 5 to 50 mass %, The content of fiber (C) is 5 to 50 mass%. The polypropylene resin composition according to claim 1.

8. The polypropylene resin composition according to claim 1, further comprising an acid-modified polyolefin polymer (D).

9. When the total amount of the polypropylene resin composition is 100% by mass, The polypropylene resin composition according to claim 8, wherein the content of the acid-modified polyolefin polymer (D) is 0.1 to 5.0 mass%.

10. A molded article comprising the polypropylene resin composition according to any one of claims 1 to 9.

11. An injection-molded article comprising the polypropylene resin composition according to any one of claims 1 to 9.

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