Polypropylene-based resin composition

Abstract

[Problem] Increasing the flame retardancy of a polypropylene material combining a phosphorus-based flame retardant. [Solution] A propylene-based resin composition characterized by containing a polypropylene-based resin (A) that satisfies requirement (A1), a flame retardant (B) that satisfies requirement (B1), and fibers (C) that satisfy requirement (C1), and characterized by satisfying condition 1 and condition 2.

Description

Polypropylene-based resin composition

[0001] The present invention relates to a polypropylene-based resin composition. More specifically, it relates to a polypropylene-based resin composition containing a phosphorus-based flame retardant and glass fiber and having excellent flame shielding properties.

[0002] Polyolefin-based resins are widely used in various fields such as building materials, automotive parts, packaging materials, and household appliances, taking advantage of their chemical and mechanical property advantages, and their applications have also been expanding. However, many polyolefin-based resins are flammable, and flame retardancy is required depending on the application. Conventionally, a widely used flame retardant method is a system combining a bromine-based flame retardant and antimony trioxide as a flame retardant aid.

[0003] However, the flame retardant method using a bromine-based flame retardant has poor shape retention due to its material properties and is difficult to withstand direct flame for a long time. On the other hand, a flame retardant method using a phosphorus-based flame retardant, especially a phosphorus-based flame retardant that forms a carbonaceous char after combustion, is expected to be able to carbonize the flame contact surface and have fire resistance and withstand direct flame for a relatively long time.

[0004] On the other hand, in the case of materials using a phosphorus-based flame retardant such as Patent Document 1 and Patent Document 2, although many studies have been conducted on self-extinguishing properties such as oxygen index and UL94 V test, there have been few examples of in-depth studies on fire resistance performance.

[0005] In recent years, studies such as those in Patent Document 3 have been reported, where the fire resistance performance of test pieces obtained by compounding a phosphorus-based flame retardant and glass fiber has been studied.

[0006] However, the direct flame contact time of the technology disclosed in Patent Document 3 cannot be said to be sufficient. For example, in the Chinese GB / T 38031-2020 standard, assuming a fire in an EV vehicle, it is specified that "smoke / fire does not come out of the battery pack for 5 minutes after the battery cell catches fire in the state of the battery pack", but the invention of Patent Document 3 has not discussed the fire resistance performance for 5 minutes or more. That is, it can be seen that the problem of providing a material that can exhibit the performance of withstanding direct flame for a long time required by society in the future still remains.

[0007] Japanese Patent Publication No. 4753498, Japanese Patent Publication No. 5462584, Japanese Unexamined Patent Publication No. 7329528

[0008] The objective of this invention is to address the above-mentioned problems and provide a material system combining a phosphorus-based flame retardant, glass fiber, and polypropylene that exhibits excellent flame-retardant properties and can withstand prolonged exposure to flames.

[0009] In order to solve the above problems, the present invention was developed through diligent research. As a result, it was discovered that a polypropylene resin composition can solve the above problems by blending a specific flame retardant and a specific fiber in a specific ratio with a polypropylene resin, and further optimizing the melt flow rate (hereinafter sometimes abbreviated as MFR) of the propylene resin composition. Based on these findings, the present invention was completed.

[0010] In other words, the present invention has the following configuration: [1] A propylene resin composition characterized by containing a polypropylene resin (A) that satisfies the following requirement (A1), a flame retardant (B) that satisfies the following requirement (B1), and a fiber (C) that satisfies the following requirement (C1), and satisfying the following conditions 1 and 2. Requirement (A1) The polypropylene resin (A) contains at least one propylene polymer selected from the group consisting of propylene homopolymer, propylene random copolymer, and propylene block copolymer. Requirement (B1) The flame retardant (B) is an organic flame retardant. Requirement (C1) The fiber (C) is a glass fiber with a fiber length of 1 mm or more and 20 mm or less. Condition 1: The propylene resin composition contains 20 to 70% by weight of polypropylene resin (A), 15 to 30% by weight of flame retardant (B), and 15 to 50% by weight of fiber (C) (however, the total of polypropylene resin (A), flame retardant (B), and fiber (C) is 100% by weight). Condition 2: The melt flow rate (MFR, 230°C, 2.16 kg load) of the propylene resin composition is 9 g / 10 min or less. [2] The propylene resin composition according to [1], wherein the polypropylene resin (A) further satisfies the following requirement (A2). Requirement (A2): The polypropylene resin (A) contains at least two types of polypropylene resin (Aa) and polypropylene resin (Ab), and the melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene resin (Aa) is in the range of 60 to 2000 g / 10 min. [3] The propylene resin composition according to [1], wherein the flame retardant (B) is a phosphorus-based flame retardant. [4] The propylene resin composition according to [3], wherein the flame retardant (B) is a polyphosphate salt. [5] A molded article comprising the propylene resin composition according to any one of [1] to [4].

[0011] The present invention makes it possible to provide a material with excellent flame-retardant properties that can withstand prolonged exposure to flames. Embodiments for carrying out the invention

[0012] The present invention is a propylene resin composition characterized by containing a polypropylene resin (A) that satisfies the following requirement (A1), a flame retardant (B) that satisfies the following requirement (B1), and a fiber (C) that satisfies the following requirement (C1), and satisfying the following conditions 1 and 2. Requirement (A1) The polypropylene resin (A) contains at least one propylene polymer selected from the group consisting of propylene homopolymer, propylene random copolymer, and propylene block copolymer. Requirement (B1) The flame retardant (B) is an organic flame retardant. Requirement (C1) The fiber (C) is a glass fiber with a fiber length of 1 mm or more and 20 mm or less. Condition 1: The propylene resin composition contains 20-70% by weight of polypropylene resin (A), 15-30% by weight of flame retardant (B), and 15-50% by weight of fiber (C) (however, the total of polypropylene resin (A), flame retardant (B), and fiber (C) is 100% by weight). Condition 2: The melt flow rate (MFR, 230°C, 2.16 kg load) of the propylene resin composition is 9 g / 10 min or less.

[0013] The details of each item regarding the propylene-based resin composition of the present invention are described below.

[0014] 1. Propylene-based resin composition The propylene-based resin composition of the present invention satisfies the following condition 1.

[0015] Condition 1: The propylene resin composition contains 20-70% by weight of polypropylene resin (A), 15-30% by weight of flame retardant (B), and 15-50% by weight of fiber (C) (however, the total of polypropylene resin (A), flame retardant (B), and fiber (C) is 100% by weight). Details of polypropylene resin (A), flame retardant (B), and fiber (C) will be described later.

[0016] The propylene resin composition of the present invention must contain 20 to 70% by weight of polypropylene resin (A), preferably 26 to 64% by weight, more preferably 32 to 58% by weight, and more preferably 38 to 52% by weight. The flame retardant (B) must be contained in an amount of 15 to 30% by weight, preferably 16 to 29% by weight, more preferably 17 to 28% by weight, and more preferably 18 to 27% by weight. The fiber (C) must be contained in an amount of 15 to 50% by weight, preferably 20 to 45% by weight, more preferably 25 to 40% by weight, and more preferably 30 to 35% by weight. By setting the content of polypropylene resin (A), flame retardant (B), and fiber (C) within these ranges, it becomes possible to provide a material that can achieve both flame resistance that can withstand prolonged exposure to flames and fluidity with excellent moldability. That is, if there is too much flame retardant (B) and fiber (C), flame resistance will improve, but fluidity will deteriorate and moldability will tend to decrease. Conversely, if there is too little flame retardant (B) and fiber (C), sufficient flame protection may not be achieved.

[0017] The propylene resin composition of the present invention further satisfies the following condition 2.

[0018] Condition 2: The melt flow rate (MFR, 230°C, 2.16 kg load) of the propylene resin composition is 9 g / 10 min or less.

[0019] In the present invention, sufficient flame retardancy can be achieved by setting the melt flow rate of the propylene resin composition to 9 g / 10 min or less. The melt flow rate of the propylene resin composition is preferably 1 to 8 g / 10 min, more preferably 2 to 7 g / 10 min. The melt flow rate of the propylene resin composition can be adjusted by selecting the melt flow rate of the polypropylene resin (A), the content of the flame retardant (B) and fibers (C), the length of the fibers (C) used as raw materials, and the conditions during melt mixing (for example, the molding back pressure during pellet production or injection molding, and the type of screw used during mixing).

[0020] (1) Polypropylene resin (A) The details of the polypropylene resin (A) used in the present invention will be described below.

[0021] Requirement (A1) The polypropylene resin (A) used in the present invention comprises at least one propylene polymer selected from the group consisting of propylene homopolymer, propylene random copolymer, and propylene block copolymer. A propylene-α-olefin random copolymer is preferred as the propylene random copolymer. A propylene-α-olefin block copolymer is preferred as the propylene block copolymer. Hereinafter, in this specification, propylene-α-olefin block copolymer and propylene-α-olefin random random copolymer may be simply referred to as "propylene-α-olefin copolymer". Preferably used propylene-α-olefin copolymers are copolymers in which propylene and α-olefins having 2 to 8 carbon atoms other than propylene are comonomers, and are typically random copolymers or block copolymers of propylene and α-olefins with a propylene content of 70 to 99.99% by weight (i.e., a comonomer content of 0.01 to 30% by weight), preferably 80 to 99% by weight (a comonomer content of 1 to 20% by weight), and more preferably 90 to 98% by weight (a comonomer content of 2 to 10% by weight). Alternatively, a mixture of random copolymers or block copolymers of different α-olefins may also be used.

[0022] Furthermore, the comonomer, which is an α-olefin having 2 to 8 carbon atoms other than propylene, that is copolymerized with propylene may be used alone or in combination of two or more types. Specific examples of propylene-α-olefin copolymers include binary copolymers such as propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene-pentene-1 copolymer, propylene-hexene-1 copolymer, and propylene-octene-1 copolymer, as well as terpolymers such as propylene-ethylene-butene-1 copolymer and propylene-ethylene-hexene-1 copolymer, with propylene-ethylene random copolymer and propylene-ethylene-butene-1 random copolymer being preferred.

[0023] Examples of α-olefins having 2 to 8 carbon atoms other than propylene include ethylene, 1-butene, 2-methyl-1-propene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3,3-dimethyl-1-butene, 1-heptene, methyl-1-hexene, dimethyl-1-pentene, ethyl-1-pentene, trimethyl-1-butene, and 1-octene. By using the above-mentioned α-olefins in the above amounts as comonomers for the propylene-α-olefin copolymer, it is possible to maximize the effects of the propylene-based resin composition of the present invention.

[0024] Here, the propylene, ethylene, and α-olefins having 4 to 8 carbon atoms (hereinafter sometimes abbreviated as "the monomer") that are comonomers of the polypropylene resin (A) may be manufactured from biomass or derived from chemical recycling. The propylene, ethylene, and α-olefins having 4 to 8 carbon atoms that are comonomers of the polypropylene resin (A) may consist solely of the monomers derived from biomass, or solely of the monomers derived from fossil fuels. Alternatively, both the monomers derived from biomass and those derived from fossil fuels may be included. Furthermore, the propylene, ethylene, and α-olefins having 4 to 8 carbon atoms that are comonomers of the polypropylene resin (A) may consist solely of the monomers derived from chemical recycling, or solely of the monomers derived from fossil fuels. Alternatively, both the monomers derived from chemical recycling and those derived from fossil fuels may be included. Furthermore, the comonomers of the polypropylene resin (A), such as propylene, ethylene, and α-olefins having 4 to 8 carbon atoms, can be used in any combination of biomass-derived monomers, chemically recycled monomers, and fossil fuel-derived monomers.

[0025] Furthermore, recycled resin can be used as the polypropylene resin (A). The ratio of recycled resin to the total polypropylene resin (A) can be arbitrarily selected as long as it does not impede the effects of the present invention. As for the recycled resin, any recycled resin can be used regardless of its origin, as long as it does not impede the effects of the present invention, such as resins derived from discarded automobiles, battery cases, home appliances, contact lens polymerization types, and logistics materials. It is also possible to mix these recycled resins with the aforementioned monomers derived from biomass, chemical recycling, and fossil fuels in any ratio.

[0026] Furthermore, from the viewpoint of moldability, the polypropylene resin (A) preferably has a melting point of 100 to 170°C, and more preferably 150 to 165°C. The melting point of the polypropylene resin can be appropriately controlled mainly by the type of propylene and other α-olefins used as raw materials, the copolymerization ratio, the melt flow rate (MFR), etc. In this specification, "melting point" refers to the melting peak temperature measured by a differential scanning calorimeter (DSC).

[0027] The polypropylene resin (A) used in the present invention has a melt flow rate (MFR) measured in accordance with JIS K7210 [measurement temperature 230°C, load 2.16 kg (21.18 N)] preferably 1.0 to 200 g / 10 min, more preferably 5.0 to 150 g / 10 min, and even more preferably 10 to 100 g / 10 min. By setting the melt flow rate (MFR) within this range, the propylene resin composition of the present invention and the molded articles made therefrom can maintain good flame resistance, fire retardancy, and moldability, while exhibiting various mechanical properties, such as scratch resistance and flexural strength. In other words, if the melt flow rate (MFR) is less than 1 g / 10 min, the load when molding the propylene resin composition of the present invention will increase, the moldability will deteriorate, and the appearance of the molded article may deteriorate due to discoloration, etc. Conversely, if it exceeds 200 g / 10 min, the flame-retardant properties may decrease, and the scratch resistance and flexural strength may be impaired. In the case where the polypropylene resin (A) contains two or more types of propylene polymers, any of these two or more types of propylene polymers may have a melt flow rate (MFR) within the above range, or even if some or all of the two or more types of propylene polymers have a melt flow rate (MFR) outside the above range, the polypropylene resin (A) as a whole may have a melt flow rate (MFR) within the above range.

[0028] Furthermore, in the present invention, the polypropylene resin (A) having an isotactic pentad fraction (mmmm fraction) of 96% or more, which indicates its degree of crystallinity, is preferably used, and more preferably has an isotactic pentad fraction of 97% or more. An isotactic pentad fraction of 96% or more is preferable because it allows for good flame resistance in the propylene resin composition of the present invention, as well as good various mechanical properties, such as scratch resistance and flexural strength. While the detailed reasons are not clear, it is possible that effects such as the orientation of crystals on the surface of the molded body in the polypropylene resin (A) are involved. The degree of crystallinity of the polypropylene resin (A) can be controlled by controlling the molecular weight distribution through the copolymerization ratio of the raw materials and the catalyst used. Note that the above isotactic pentad fraction (mmmm) is... １３ This value is measured using 13C-NMR (nuclear magnetic resonance spectroscopy), and is the nuclear magnetic resonance spectrum due to isotopic carbon. １３ This is the isotactic fraction of pentad units in polypropylene molecular chains, measured using 13C NMR. In other words, the isotactic pentad fraction is the fraction of propylene units in which five propylene monomer units are isotactically linked. Specifically, １３ The isotactic pentad units are measured using the intensity fraction of mmmm peaks among the total absorption peaks in the methyl carbon region of the 13C-NMR spectrum, for example, using a 270MHz FT-NMR instrument manufactured by JEOL Ltd.

[0029] The catalyst used to obtain the polypropylene resin (A) used in the present invention is not particularly limited, and known catalysts can be used. For example, a so-called Ziegler-Natta catalyst, which combines a titanium compound and organoaluminum (for example, described in the Polypropylene Handbook (first edition, first printing, May 15, 1998), etc.), or a metallocene catalyst (for example, described in Japanese Patent Publication No. 5-295022, etc.) can be used.

[0030] The polymerization process used to obtain the polypropylene resin (A) used in the present invention is not particularly limited, and known polymerization processes can be used. For example, slurry polymerization, bulk polymerization, gas-phase polymerization, etc., can be used. In addition, either batch polymerization or continuous polymerization can be used, and if desired, a multi-stage continuous polymerization method such as two-stage or three-stage polymerization may be used. It can also be produced by mechanically melt-kneading two or more propylene polymers. Furthermore, various polypropylene resins that can be used as polypropylene resin (A) are commercially available from many companies, for example, the Novatec series and Nova Orbis series from Nippon Polypropylene Co., Ltd. It is also possible to purchase and use a product with the desired physical properties from these commercially available products.

[0031] The polypropylene resin (A) used in the present invention preferably further satisfies the following requirement (A2). Requirement (A2) The polypropylene resin (A) comprises at least two types of polypropylene resin (Aa) and polypropylene resin (Ab), and the melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene resin (Aa) is in the range of 60 to 2000 g / 10 min. The melt flow rates (MFR) of the at least two types of polypropylene resin (Aa) and polypropylene resin (Ab) may be the same or different, but it is preferable that the melt flow rate (MFR) of the polypropylene resin (Aa) is greater than the melt flow rate (MFR) of the polypropylene resin (Ab) because it makes it easier to set the melt flow rate (MFR) of the polypropylene resin (A) to a preferred desired range. In particular, one embodiment of the present invention involves producing masterbatches (hereinafter sometimes referred to as "flame retardant masterbatch" and "fiber masterbatch") by kneading a flame retardant (B) and fibers (C) into different polypropylene resins (carrier resins), and then, if necessary, further kneading them with another polypropylene resin in a molding machine. In this case, for the fiber masterbatch, if the melt flow rate (MFR) of the carrier resin is low, the dispersion of fibers (C) will be poor, so it is preferable to use a polypropylene resin (Aa) with a relatively high melt flow rate (MFR, 230°C, 2.16 kg load) in the range of 60 to 2000 g / 10 min as the carrier resin. On the other hand, in the present invention, if the melt flow rate (MFR) of the polypropylene resin (A) is too high, the flame-retardant properties will decrease, so it is necessary to adjust the overall melt flow rate (MFR) of the polypropylene resin (A) by using a polypropylene resin with a low melt flow rate (MFR). Therefore, in a configuration using a masterbatch in which fibers (C) are kneaded with a polypropylene resin (carrier resin), using at least two types of polypropylene resins is preferable for adjusting various physical properties.In this case, it is preferable to use the other polypropylene resin, i.e., polypropylene resin (Ab), as the carrier resin in the masterbatch of the flame retardant (B), as it is easy to adjust the flame retardant (B) and fibers (C) to the desired concentration, and the mixing operation is also simple.

[0032] Here, the melt flow rate (MFR) of the polypropylene resin (Aa) is preferably 60 to 1000 g / 10 min, more preferably 80 to 900 g / 10 min, even more preferably 100 to 800 g / 10 min, and even more preferably 150 to 700 g / 10 min. Furthermore, the melt flow rate (MFR) of the polypropylene resin (A) as a whole, which includes at least two types of polypropylene resins (Aa) and polypropylene resin (Ab), is preferably 1.0 to 200 g / 10 min, more preferably 5.0 to 150 g / 10 min, and even more preferably 10 to 100 g / 10 min, similar to the melt flow rate (MFR) of the polypropylene resin (A) described above. It should be noted that it is preferable for the melt flow rate (MFR) of the polypropylene resin (Aa) to be greater than that of the polypropylene resin (Ab), as stated above. In this specification, the melt flow rate (MFR) shall be the value measured in accordance with JIS K7210, at a test temperature of 230°C and a load of 2.16 kg. When multiple polypropylene resins are mixed to form polypropylene resin (A), the melt flow rate (MFR) value obtained by calculating using the logarithmic addition rule described in, for example, Japanese Patent No. 6331720 (see, for example, formula (1) below) may be used. Ａ ) represents the melt flow rate of the resin portion obtained by calculation, and hereafter MFR Ａ It is sometimes abbreviated as log(MFR). Ａ ) = {(Component (PP-A) weight %) × log(Component (PP-A) MFR) + (Component (PP-B) weight %) × log(Component (PP-B) MFR) + (Component (PP-C) weight %) × log(Component (PP-C) MFR)} / 100 ... Equation (1)

[0033] The types of polypropylene resin (Aa) and polypropylene resin (Ab) (i.e., the types of propylene polymers), preferred melting points, and preferred isotactic pentad fractions are as detailed for polypropylene resin (A). Furthermore, polypropylene resin (Ab) may contain two or more types.

[0034] The ratio of the total content of polypropylene resin (Aa) to the total content of polypropylene resin (Ab) in polypropylene resin (A) can be arbitrarily set, taking into account the total melt flow rate (MFR) of polypropylene resin (A). That is, as described above, in the present invention, it is important to set the melt flow rate (MFR) of polypropylene resin (A) to a desired range and adjust the content of flame retardant (B) to a specific range within that desired range.

[0035] Furthermore, when using polypropylene resin (Aa) and polypropylene resin (Ab) in polypropylene resin (A), as described in the section on polypropylene resin (A), recycled resin and materials using biomass-derived monomer, chemically recycled monomer, and fossil fuel-derived monomer can be selected and used in any proportion for each of polypropylene resin (Aa) and polypropylene resin (Ab) within a range that does not impair the effects of the present invention.

[0036] Furthermore, when polypropylene resin (Aa) and polypropylene resin (Ab) are used as preferred embodiments of polypropylene resin (A), various polypropylene resins that can be used as polypropylene resin (Aa) and polypropylene resin (Ab) are commercially available from many companies, for example, the Novatec series and Nova Orbis series from Nippon Polypropylene Co., Ltd. It is also possible to purchase a product with the desired physical properties from these commercially available products, or to adjust the purchased product to the desired physical properties by further processing it with peroxide or other operations before use.

[0037] (2) Flame retardant (B) The flame retardant (B) used in the present invention will be described in detail below.

[0038] Requirement (B1): The flame retardant (B) used in the present invention is an organic flame retardant. Generally, in order to exhibit the required flame retardancy, more amount of inorganic flame retardant is required, and when attempting to exhibit high-level flame retardancy, the specific gravity increases. In contrast, since organic flame retardants can exhibit flame retardancy with a relatively low addition amount, it is possible to exhibit high-level flame retardancy with a relatively low specific gravity. Therefore, in the present invention, it is necessary to use an organic flame retardant as the flame retardant (B).

[0039] The organic flame retardant used in the present invention is not particularly limited, and various organic flame retardants such as halogen-based, phosphorus-based, and nitrogen compounds represented by guanidine-based can be used. However, phosphorus-based flame retardants are preferable because they are likely to exhibit good flame shielding properties in the propylene-based resin composition of the present invention.

[0040] As the phosphorus-based flame retardant, any can be used as long as it is generally used as a flame retardant for polyolefins. Examples include various substituted and modified compounds such as trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, tricyclohexyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, dicresyl phenyl phosphate, dimethyl ethyl phosphate, tricresyl phosphate, methyl dibutyl phosphate, ethyl dipropyl phosphate, hydroxyphenyl diphenyl phosphate, etc., phosphate compounds, phosphazene derivatives containing phosphorus and nitrogen, and other compounds or mixtures. These phosphorus-based flame retardants may be used alone or in combination of two or more.

[0041] Also, in one preferred embodiment of the present invention, the phosphorus-based flame retardant is a polyphosphate. When using polyphosphate as the organic flame retardant, it is suitable for flame shielding properties because it forms an intumescent layer by the reaction during combustion. Examples of the polyphosphate include phosphates as described in paragraphs

[0015] to

[0021] of Patent No. 4753498 of the above [Patent Document 1].

[0042] In addition to the phosphorus-based flame retardant, other organic flame retardants that do not fall under phosphorus-based flame retardants such as halogen-based and nitrogen compounds, for example, halogen-based flame retardants, can also be used.

[0043] As the halogen-based flame retardant, for example, organic halogenated aromatic compounds such as halogenated diphenyl compounds, halogenated bisphenol-based compounds, halogenated bisphenol-bis(alkyl ether) compounds, and halogenated phthalimide-based compounds are preferable, and among them, halogenated bisphenol-bis(alkyl ether) compounds are more preferable. As the above-mentioned halogenated diphenyl compounds, for example, halogenated diphenyl ether-based compounds, halogenated diphenyl ketone-based compounds, halogenated diphenyl alkane-based compounds, etc. can be mentioned, and among them, halogenated diphenyl alkane compounds such as decabromodiphenyl ethane are preferable.

[0044] As the above-mentioned halogenated bisphenol-based compounds, for example, halogenated bisphenyl alkanes, halogenated bisphenyl ethers, halogenated bisphenyl thioethers, halogenated bisphenyl sulfones, etc. can be mentioned, and among them, halogenated bisphenyl thioethers such as bis(3,5-dibromo-4-hydroxyphenyl)sulfone are preferable.

[0045] Examples of the above halogenated bisphenol bis(alkyl ether) compounds include (3,5-dibromo-4-2,3-dibromopropoxyphenyl)-(3-bromo-4-2,3-dibromopropoxyphenyl)methane, 1-(3,5-dibromo-4-2,3-dibromopropoxyphenyl)-2-(3-bromo-4-2,3-dibromopropoxyphenyl)ethane, 1-(3,5-dibromo-4-2,3-dibromopropoxyphenyl)-3-(3-bromo-4-2,3-dibromopropoxyphenyl)propane, and 2,2-bis(3,5- Dibromo-4-2,3-dibromopropoxyphenyl)propane, (3,5-dichloro-4-2,3-dibromopropoxyphenyl)-(3-chloro-4-2,3-dibromopropoxyphenyl)methane, 1-(3,5-dichloro-4-2,3-dibromopropoxyphenyl)-2-(3-chloro-4-2,3-dibromopropoxyphenyl)ethane, 1-(3,5-dichloro-4-2,3-dibromopropoxyphenyl)-3-(3-chloro-4-2,3-dibromopropoxyphenyl)propane, bis(3,5-dibromo 2-bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl)methane, 1,2-bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl)ethane, 1,3-bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl)propane, bis(3,5-dichloro-4-2,3-dibromopropoxyphenyl)methane, 1,2-bis(3,5-dichloro-4-2,3-dibromopropoxyphenyl)ethane, 1,3-bis(3,5-dichloro-4-2,3-dibromopropoxyphenyl)propane, 2-bis(3,5-dichloro-4-2,3-dibromopropoxyphenyl) Nyl)propane, (3,5-dibromo-4-2,3-dibromopropoxyphenyl)-(3-bromo-4-2,3-dibromopropoxyphenyl)ketone, (3,5-dichloro-4-2,3-dibromopropoxyphenyl)-(3-chloro-4-2,3-dibromopropoxyphenyl)ketone, bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl)ketone, bis(3,5-dichloro-4-2,3-dibromopropoxyphenyl)ketone, (3,5-dibromo-4-2,3-dibromopropoxyphenyl)-(3-bromo-4-2,3-dibromopropoxyphenyl) ether, (3,5-dichloro-4-2,3-dibromopropoxyphenyl)-(3-chloro-4-2,3-dibromopropoxyphenyl) ether, bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl) ether, bis(3,5-dichloro-4-2,3-dibromopropoxyphenyl) ether, (3,5-dibromo-4-2,3-dibromopropoxyphenyl) ether (xyphenyl)-(3-bromo-4-2,3-dibromopropoxyphenyl) thioether, (3,5-dichloro-4-2,3-dibromopropoxyphenyl)-(3-chloro-4-2,3-dibromopropoxyphenyl) thioether, bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl) thioether, bis(3,5-dichloro-4-2,3-dibromopropoxyphenyl) thioether Examples include tetrabromobisphenol A, (3,5-dibromo-4-2,3-dibromopropoxyphenyl)-(3-bromo-4-2,3-dibromopropoxyphenyl)sulfone, (3,5-dichloro-4-2,3-dibromopropoxyphenyl)-(3-chloro-4-2,3-dibromopropoxyphenyl)sulfone, bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl)sulfone, and bis(3,5-dichloro-4-2,3-dibromopropoxyphenyl)sulfone, among which brominated bisphenol A (brominated aliphatic ether), brominated bisphenol S (brominated aliphatic ether), chlorinated bisphenol A (chlorinated aliphatic ether), chlorinated bisphenol S (chlorinated aliphatic ether), and especially etherified tetrabromobisphenol A and etherified tetrabromobisphenol S are preferred.

[0046] Examples of etherified tetrabromobisphenol A include tetrabromobisphenol A-bis(2,3-dibromopropyl ether) and 2,2-bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl)propane. An example of etherified tetrabromobisphenol S is bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl)sulfone. Among these halogenated flame retardants, brominated flame retardants are preferred because they have a high flame retardant effect and do not decompose easily even when subjected to thermal history during the manufacture and molding of the polypropylene resin composition of the present invention.

[0047] Examples of the nitrogen compounds mentioned above include melamine, piperazine, 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,N',N'-diethylethylenediamine, 1,2-propanediamine, and 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, acrylicguanamine, 2,4-diamino-6-nonyl-1,3,5-tri Azine, 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, 2,4-diamino-6-mercapto-1,3,5-triazine Compounds that replace riazine, 2-amino-4,6-dimercapto-1,3,5-triazine, anmeline, benzguanamine, acetoguanamine, phthalodiguanamine, melamine cyanurate, melamine pyrophosphate, butylenediguanamine, norbornenediguanamine, methylenediguanamine, ethylenedimelamine, trimethylenedimelamine, tetramethylenedimelamine, hexamethylenedimelamine, 1,3-hexylenedimelamine, etc. Commercially available products include ADEKA Corporation's ADEKA Stab FP2000, FP2100, FP2200, FP2500S, and ammonium polyphosphate.

[0048] When phosphorus-based flame retardants are used in combination with various organic flame retardants such as halogen-based and nitrogen compounds, the organic flame retardants may be used alone or in combination of two or more. For example, phosphorus-based flame retardants can be used in combination with organic halogen-based flame retardants and nitrogen compounds. Furthermore, as described above, they can also be used in the form of a so-called masterbatch, which is pre-mixed into the polypropylene resin (A) or the like at a relatively high concentration.

[0049] (3) Fiber (C) The details of the fiber (C) used in the present invention will be described below.

[0050] Requirement (C1) The fiber (C) is a glass fiber with a fiber length of 1 mm or more and 20 mm or less. The fiber (C) not only improves physical properties such as rigidity and impact strength in the propylene-based resin composition and molded articles containing the present invention, but also has characteristics that contribute to the improvement of additional physical properties such as heat resistance, dimensional stability (reduction of the coefficient of linear expansion, etc.), low shrinkage, and scratch resistance.

[0051] (3-1) Type and Manufacturing Method of Glass Fibers Fiber (C) is glass fiber as described above. Using glass fiber as fiber (C) is preferable in terms of ease of manufacture and economic efficiency, as well as in terms of obtaining good flame resistance in the propylene resin composition and molded articles containing the same of the present invention. Two or more types of fiber (C) can be used in combination to further improve the effects of the present invention, and can also be used in the form of a so-called masterbatch in which the fiber (C) is previously contained in the polypropylene resin (A) or the like at a relatively high concentration, as described above. Furthermore, glass beads, glass balloons, mica, and various inorganic or organic fillers that do not fall under the category of fiber (C) can also be used in combination within a range that does not significantly impair the effects of the present invention.

[0052] The glass fibers are not particularly limited and can be used in any way. Examples of glass types used in the fibers include E-glass, C-glass, A-glass, and S-glass, with E-glass being preferred. The manufacturing method of the glass fibers is not particularly limited, and any glass fibers manufactured by various known manufacturing methods can be used. Therefore, any desired product can be selected from a variety of commercially available products.

[0053] The fiber diameter of the glass fibers is typically 3 to 25 μm, preferably 5 to 23 μm, more preferably 6 to 20 μm, more preferably 7 to 21 μm, and particularly preferably 9 to 19 μm. By setting the fiber diameter of the glass fibers within this range, dispersion in the polypropylene resin is improved, while the glass fibers are less prone to breakage, resulting in improved flame resistance and various mechanical properties, which is therefore more preferable. If the fiber diameter is less than 3 μm, the glass fibers may be prone to breakage during the manufacture and molding of the propylene resin composition and molded articles containing the same of the present invention. On the other hand, if it exceeds 25 μm, the aspect ratio of the fibers decreases, which may reduce the flame resistance, rigidity, and impact strength of the propylene resin composition and molded articles containing the same of the present invention.

[0054] Furthermore, the glass fiber (C) used has a fiber length of 1 mm to 20 mm, preferably 2 to 18 mm, more preferably 3 to 16 mm, even more preferably 4 to 15 mm, particularly preferably 5 to 14 mm, and most preferably 6 to 13 mm. By using glass fiber of such length as fiber (C), it is possible to maintain the flame resistance of the propylene-based resin composition of the present invention within a good range, while simultaneously maintaining the length of the glass fiber in the propylene-based resin composition within a range that is easy to handle, including during molding, thereby improving moldability (fluidity). In other words, if the fiber length is less than 1 mm, it may reduce the flame resistance, rigidity, impact strength, and other physical properties of the propylene-based resin composition of the present invention and the molded article containing it, while if it exceeds 20 mm, it may reduce moldability (fluidity).

[0055] In this case, the fiber length refers to the length when glass fibers are used as raw materials. However, this does not apply to glass fiber-containing pellets, which are produced by melt extrusion and the so-called plutrusion method, where multiple continuous glass fibers are aggregated and integrated. In such cases, roving-like materials are usually used. Furthermore, two or more types of glass fibers can be used in combination.

[0056] The fiber length can be determined from values ​​measured using a microscope or calipers. Furthermore, when obtaining glass fiber-containing pellets using methods such as the so-called plutonization method, the length of the glass fibers within the pellet is substantially equal to the length of one side (in the extrusion direction) of the pellet, resulting in a "glass fiber-containing pellet." In this case, the length of the pellet can be used as the glass fiber length. The fiber diameter can also be determined from values ​​measured using a microscope or calipers. If the glass fibers are commercially available, the values ​​listed in the catalog can be used as reference for fiber length and fiber diameter.

[0057] Glass fibers can be used in both surface-treated and untreated forms, but it is preferable to use glass fibers that have been surface-treated with so-called sizing agents such as organic silane coupling agents, titanate coupling agents, aluminate coupling agents, zirconate coupling agents, silicone compounds, higher fatty acids, fatty acid metal salts, and fatty acid esters, in order to improve dispersibility in polypropylene resin (A). Examples of organic silane coupling agents used for surface treatment include vinyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, and 3-acryloxypropyltrimethoxysilane. Examples of titanate coupling agents include isopropyltriisostearoyl titanate, isopropyltris(dioctyl pyrophosphate) titanate, and isopropyltri(N-aminoethyl) titanate. Examples of aluminate coupling agents include acetalkoxyaluminum diisopropylate. Examples of zirconate coupling agents include tetra(2,2-diallyloxymethyl)butyl, di(tridecyl)phosphytozirconate; neopentyl(diallyl)oxy, and trineodecanoylzirconate. Examples of the silicone compound include silicone oil and silicone resin.

[0058] Furthermore, examples of higher fatty acids used for surface treatment include oleic acid, capric acid, lauric acid, palmitic acid, stearic acid, montanic acid, caleic acid, linoleic acid, rosinic acid, linolenic acid, undecanoic acid, and undecenoic acid. Examples of higher fatty acid metal salts include fatty acids with 9 or more carbon atoms, such as sodium salts, lithium salts, calcium salts, magnesium salts, zinc salts, and aluminum salts of stearic acid and montanic acid. Among these, calcium stearate, aluminum stearate, calcium montanate, and sodium montanate are preferred. Examples of fatty acid esters include polyhydric alcohol fatty acid esters such as glycerin fatty acid esters, alpha-sulfone fatty acid esters, polyoxyethylene sorbitan fatty acid esters, sorbitan fatty acid esters, polyethylene fatty acid esters, and sucrose fatty acid esters. The amount of the surface treatment agent used is not particularly limited, but 0.01 to 5 parts by weight and more preferably 0.1 to 3 parts by weight per 100 parts by weight of glass fiber is preferred.

[0059] Furthermore, the glass fibers may be those that have been treated (surface-treated) with a sizing agent. Examples of sizing agents include epoxy sizing agents, aromatic urethane sizing agents, aliphatic urethane sizing agents, acrylic sizing agents, and maleic anhydride-modified polyolefin sizing agents. Since these sizing agents need to melt during melt-kneading with the polypropylene resin (A), it is preferable that they melt at 200°C or below.

[0060] The glass fibers may also be so-called chopped strand glass fibers, which are obtained by cutting fiber filaments to a desired length, as long as they do not hinder the effects of the present invention. Specific examples of glass fibers include those manufactured by Nippon Electric Glass Co., Ltd. (T480H).

[0061] Furthermore, these glass fibers may also be used as "glass fiber-containing pellets" which are formed by melt-extruding a large number of continuous glass fibers together using a method such as the so-called plutonization method, and wherein the length of the glass fibers in the pellet is substantially the same as the length of one side (extrusion direction) of the pellet. This is more preferable because it further enhances the flame resistance, rigidity, impact strength, and other physical properties of the propylene resin composition of the present invention and the molded product made therefrom. In this case, "substantially" specifically means that, based on the total number of glass fibers in the glass fiber-containing pellet, 50% or more, preferably 90% or more, have a length that is the same as the length (extrusion direction) of the glass fiber-containing pellet, and that there is almost no fiber breakage during the preparation of the pellet.

[0062] The method for manufacturing these glass fiber-containing pellets is not particularly limited, but for example, it is preferable to manufacture them using a resin extruder, in which a large number of continuous glass fibers are drawn from a fiber rack through a crosshead die, and then melt-extruded (impregnated) with an arbitrary amount of polypropylene resin in a molten state to aggregate and integrate the large number of glass fibers (pultrusion method, pull-out method), as this method results in almost no fiber breakage.

[0063] The length (in the extrusion direction) of the glass fiber-containing pellet depends on the glass fiber used, but as mentioned above, when used as a "glass fiber-containing pellet" where the length of the glass fiber in the pellet is substantially the same as the length of one side (in the extrusion direction) of the pellet, the length is 1 mm to 20 mm, preferably 2 to 18 mm, more preferably 3 to 16 mm, even more preferably 4 to 15 mm, particularly preferably 5 to 14 mm, and most preferably 6 to 13 mm. By setting the length of the glass fiber-containing pellet within this range, it is possible to maintain the flame resistance of the propylene-based resin composition of the present invention within a good range, while simultaneously maintaining the length of the glass fiber in the propylene-based resin composition within a range that is easy to handle, including during molding, thereby improving moldability (fluidity). In other words, if the length of the pellet is less than 1 mm, it may reduce the flame resistance, rigidity, impact strength, and other physical properties of the propylene-based resin composition of the present invention and the molded product made therefrom, while if it exceeds 20 mm, it may reduce moldability (fluidity), etc. Furthermore, the fiber diameter of the glass fibers is typically 3 to 25 μm, preferably 5 to 23 μm, more preferably 6 to 20 μm, more preferably 7 to 21 μm, and particularly preferably 9 to 19 μm. By setting the fiber diameter of the glass fibers within this range, the dispersion in the polypropylene resin is improved while the glass fibers are less prone to breakage. This makes it possible to maintain good fluidity and mechanical properties in the resulting polypropylene resin composition while simultaneously exhibiting good flame retardancy and fire resistance. In addition, the glass fiber content in the glass fiber-containing pellets is preferably 20% to 70% by weight, based on 100% by weight of the entire pellet. By setting the glass fiber content within this range, it is possible to improve the flame retardancy and various mechanical properties, such as rigidity and impact strength, and moldability (fluidity), of the propylene resin composition of the present invention and the molded articles obtained therefrom.In other words, if glass fiber-containing pellets with a glass fiber content of less than 20% by weight are used in the present invention, the flame resistance, rigidity, impact strength, and other physical properties of the propylene-based resin composition of the present invention and the molded product made therefrom may decrease. On the other hand, if a content of 70% by weight or more is used, the moldability (fluidity) and other properties may decrease.

[0064] (4) Additives (D) In ​​addition to the polypropylene resin (A), flame retardant (B), and fiber (C), the propylene resin composition of the present invention may optionally contain additives (D), which are ordinary components used in polypropylene resins, to the extent that the objectives of the present invention are not impaired. Examples of additives (D) include nucleating agents, molecular weight modifiers, foaming agents, pigments, ultraviolet absorbers, antioxidants, antistatic agents, neutralizing agents, metal deactivators, stabilizers, antibacterial agents, inorganic fillers, rubber-like components, etc.

[0065] As molecular weight lowering agents, for example, various organic peroxides and substances referred to as decomposition (oxidation) accelerators can be used, with organic peroxides being preferred. Specific examples of organic peroxides include benzoyl peroxide, t-butyl perbenzoate, t-butyl peracetate, t-butyl peroxyisopropyl carbonate, 2,5-dimethyl-2,5-di-(benzoylperoxy)hexane, 2,5-dimethyl-2,5-di-(benzoylperoxy)hexyne-3, t-butyl-di-peradipate, t-butylperoxy-3,5,5-trimethylhexanoate, methyl-ethyl ketone peroxide, cyclohexanone peroxide, di-t-butyl peroxide, diquyl peroxide, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexyne-3, 1,3-bis-(t-butylperoxyisopropyl)benzene, t-butylquyle peroxide, 1,1-bis- Examples include one or more substances selected from the group consisting of (t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis-(t-butylperoxy)cyclohexane, 2,2-bis-t-butylperoxybutane, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, p-cymene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, and 2,5-di-methyl-2,5-di-(hydroperoxy)hexane. However, this list is not limited to these.

[0066] There are no particular restrictions on the type of blowing agent that can be used in the present invention, and known blowing agents used in plastics, rubber, etc. can be used. In addition, any blowing agent used in various foam molding processes can be used, for example, physical blowing agents, biodegradable blowing agents (chemical blowing agents), microcapsules containing thermal expansion agents, etc. Specific examples of physical blowing agents include aliphatic hydrocarbons such as propane, butane, pentane, and hexane; alicyclic hydrocarbons such as cyclopentane and cyclohexane; halogenated hydrocarbons such as chlorodifluoromethane, difluoromethane, trifluoromethane, trichlorofluoromethane, dichlorodifluoromethane, chloromethane, dichloroethane, chloropentafluoroethane, tetrafluoroethane, difluoroethane, pentafluoroethane, trifluoroethane, trichlorotrifluoroethane, dichlorotetrafluoroethane, chloropentafluoroethane, perfluorocyclobutane, and inorganic gases such as water, carbon dioxide, and nitrogen. These compounds may be used individually or in combination. Among them, aliphatic hydrocarbons such as propane, butane, and pentane, as well as carbon dioxide, are preferred because they are inexpensive and have high solubility in polypropylene resins. In particular, when using carbon dioxide, supercritical conditions of 7.4 MPa or higher and 31°C or higher are even more preferable because they result in excellent diffusion and solubility in the resin composition.

[0067] When using a physical foaming agent, a foam regulator may be used as needed. Examples of foam regulators include inorganic degradable foaming agents such as ammonium carbonate, sodium bicarbonate, ammonium bicarbonate, and ammonium nitrite; azo compounds such as azodicarbonamide, azobisisobutyronitrile, and diazoaminobenzene; nitroso compounds such as N,N'-dinitrosopentamenethylenetetramine and N,N'-dimethyl-N,N'-dinitrosotelephthalamide; organic degradable foaming agents such as benzenesulfonyl hydrazide, p-toluenesulfonyl hydrazide, p,p'-oxybisbenzenesulfonyl semicarbazide, p-toluenesulfonyl semicarbazide, trihydrazinotriadin, and barium azodicarboxylate; inorganic powders such as talc and silica; acidic salts such as polycarboxylic acids; and reaction mixtures of polycarboxylic acids with sodium carbonate or sodium bicarbonate. These foam regulators may be used alone or in combination. When using a foam regulator, the amount of foam regulator added is preferably in the range of 0.01 to 5 parts by weight in pure form per 100 parts by weight of the resin composition. Specific examples of degradable foaming agents (chemical foaming agents) include a mixture of sodium bicarbonate and organic acids such as citric acid, azo-based foaming agents such as azodicarbonamide and barium azodicarboxylate, nitroso-based foaming agents such as N,N'-dinitrosopentamethylenetetramine and N,N'-dimethyl-N,N'-dinitrosotelephthalamide, sulfohydrazide-based foaming agents such as p,p'-oxybisbenzenesulfonyl hydrazide and p-toluenesulfonyl semicarbazide, and trihydrazinotriazine. The amount of foaming agent added is preferably in the range of 0.05 to 6.0 parts by weight, more preferably 0.05 to 3.0 parts by weight, even more preferably 0.5 to 2.5 parts by weight, and particularly preferably 1.0 to 2.0 parts by weight per 100 parts by weight of the resin composition.

[0068] Furthermore, either known organic or inorganic pigments can be used as pigments. Specifically, examples include organic pigments such as azo, anthraquinone, phthalocyanine, quinacridone, isoindolinone, diosadin, perinone, quinophthalone, and perylene pigments, as well as inorganic pigments such as ultramarine, titanium dioxide, titanium yellow, iron oxide (red iron oxide), chromium oxide, zinc oxide, and carbon black.

[0069] Examples of light stabilizers and UV absorbers include hindered amine compounds, benzotriazoles, benzophenones, and salicylates, which are effective in imparting and improving the weather resistance and durability of the polypropylene resin composition of the present invention and molded articles made therefrom. Specific examples of hindered amine compounds include: a condensate of dimethyl succinate and 1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine; poly[[6-(1,1,3,3-tetramethylbutyl)imino-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]]; tetrakis(2,2,6,6-tetramethyl-4-piperidyl)1,2,3,4-butanetetracarboxylate; Examples of benzotriazoles include tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)1,2,3,4-butanetetracarboxylate; bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate; bis-2,2,6,6-tetramethyl-4-piperidyl sebacate; benzotriazoles include 2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole; 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole; benzophenones include 2-hydroxy-4-methoxybenzophenone; 2-hydroxy-4-n-octoxybenzophenone; and salicylates include 4-t-butylphenyl salicylate; 2,4-di-t-butylphenyl3',5'-di-t-butyl-4'-hydroxybenzoate. In this case, the method of using the aforementioned light stabilizer and ultraviolet absorber in combination is highly preferable due to its significant effect in improving weather resistance and durability. These may also be used in mixtures of two or more types.

[0070] For example, antioxidants such as phenolic, phosphorus-based, and sulfur-based antioxidants are effective in providing and improving the heat resistance, processing stability, and heat aging resistance of the polypropylene resin composition of the present invention and molded articles obtained by molding it.

[0071] As antistatic agents, for example, nonionic or ionic antistatic agents are effective in imparting and improving the antistatic properties of the polypropylene resin composition of the present invention and molded articles obtained by molding it.

[0072] In particular, as antistatic agents, cationic, anionic, nonionic, and amphoteric ionic agents, as well as fatty acid partial esters such as glycerin fatty acid monoesters, can be used. Specifically, alkyltrimethylammonium salts, dialkyldimethylammonium salts, benzalkonium salts, N,N-bis(2-hydroxyethyl)-N-(3-dodecyloxy-2-hydroxypropyl)methylammonium mesosulfate, (3-laurylamidopropyl)trimethylammonium methylsulfate, stearamidopropyldimethyl-2-hydroxyethylammonium nitrate, stearamidopropyldimethyl-2-hydroxyethylammonium phosphate, cationic polymers, alkyl sulfonates, alkylbenzene sulfonates, alkyldiphenyl ether disulfonate sodium, alkyl nitrate esters, phosphorus Examples include alkyl acid ester salts, alkyl phosphate amine salts, monoglyceride stearate, pentaerythritol fatty acid esters, sorbitan monopalmitate, sorbitan monostearate, diglycerin fatty acid esters, alkyldiethanolamine, alkyldiethanolamine fatty acid monoesters, alkyldiethanolamide, polyoxyethylene dodecyl ether, polyoxyethylene alkylphenyl ether, polyethylene glycol monolaurate, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyether block copolymer, cetyl betaine, and hydroxyethylimidazoline sulfate. Two or more of these may be used in combination.

[0073] As nucleating agents, aromatic aluminum salt-based nucleating agents, aromatic sodium salt-based nucleating agents, phosphorus-based nucleating agents such as aromatic metal phosphate salts, sorbitol-based nucleating agents, rosin-based nucleating agents, petroleum resins, talc, etc., can be used. Examples of sorbitols such as alkyl-substituted benzylidene sorbitol include 1,3,2,4-dibenzylidene sorbitol, 1,3,2,4-di-(p-methylbenzylidene) sorbitol, 1,3-o-methylbenzylidene 2,4-p-methylbenzylidene sorbitol, 1,3,2,4-di-(p-ethylbenzylidene) sorbitol, and 1,3,2,4-di-(2',4'-dimethylbenzylidene) sorbitol. Examples of phosphorus-based nucleating agents include bis(4-t-butylphenyl) sodium phosphate, 2,2'-ethylidene-bis(4,6-di-t-butylphenyl) sodium phosphate, and organophosphate complexes. Other examples include sodium benzoate, p-t-butylbenzoate aluminum, sodium montana, calcium montana, aluminum oxide, kaolin clay, talc, rosins, and petroleum resins. Two or more of these may be used in combination.

[0074] Examples of metal deactivators that can be used include triazines, phosphones, epoxys, triazoles, hydrazides, and oxamides. Specifically, these include N,N'-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl]hydrazine, bis(2-phenoxypropionyl)hydrazide isophthalate, disalityloyl hydrazide decanedicarboxylate, bisbenzylidene oxalate, N,N'-bis{2-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxyl]ethyl}oxamide, 3-(N-salityloyl)amino-1,2,4-triazole, acid amides, melamine, and tris[2-t-butyl-4-thio(2'-methyl-4'-hydroxy-5-t-butyl)phenyl-5-methyl]phosphite. Two or more of these may be used in combination.

[0075] Various fatty acid metal salts can be used as neutralizing agents. Specifically, examples include saturated or unsaturated fatty acids with a molecular weight of approximately 26 to 300, such as oleic acid (unsaturated C18), stearic acid (C18), palmitic acid (C18), myristic acid (C14), lauric acid (C12), erucic acid (unsaturated C22), and behenic acid (C22), along with metal salts such as lithium, sodium, calcium, magnesium, aluminum, and zinc. Two or more of these may be used in combination.

[0076] Either organic or inorganic antibacterial agents may be used. Examples of organic antibacterial agents include chlorine-based, phenol-based, imidazole-based, or thiazole-based compounds, as well as quaternary ammonium compounds. Examples of inorganic antibacterial agents include zeolite-based, apatite-based, silica-alumina-based, ceramic-based, zirconium phosphate-based, silica gel-based, hydroxyapatite-based, or calcium silicate-based antibacterial agents containing metals such as silver and zinc.

[0077] Furthermore, specific examples of inorganic fillers include talc, barium sulfate, clay, silica, calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, glass fiber, and whiskers.

[0078] As the rubbery component, so-called elastomers or plastomers can be used. Specifically, examples include ethylene-propylene rubber, ethylene-butene-1 rubber, ethylene-hexene rubber, ethylene-octene rubber, and styrene-butadiene rubber. Various commercially available products can be obtained and used within a range that does not hinder the effects of the present invention.

[0079] 2. Method for preparing the propylene resin composition of the present invention Examples of methods for preparing the propylene resin composition of the present invention include, for example, a method of directly adding a predetermined amount of flame retardant (B), fibers (C), and optionally used additives (D) to a powder or pellet of polypropylene resin (A); a method of preparing a masterbatch containing a powder of polypropylene resin (A), a flame retardant (B), fibers (C), and optionally used additives (D) in advance, and adding the masterbatch to the pellet of polypropylene resin; a method of first preparing a masterbatch of flame retardant (B) by adding a flame retardant (B) and optionally used additives (D) to a powder or pellet of polypropylene resin (A), then preparing a masterbatch of fibers (C) by adding fibers (C) and optionally used additives (D) to the powder or pellet of polypropylene resin (A), and finally melt-kneading the obtained masterbatch of flame retardant (B) and masterbatch of fibers (C).

[0080] The polypropylene resin composition of the present invention can be obtained by any of the above methods. When using these methods, known methods such as tumbler mixers, super mixers, Henschel mixers, screw blenders, and ribbon blenders can be applied to mixing. The melt kneading method is not particularly limited, as long as it is a method of melt kneading at a temperature above the melting point of the polypropylene resin (A), for example, using a melt extruder or Banbury mixer.

[0081] In the present invention, when melt-kneading is performed during pellet manufacturing or molding (for example, injection molding), it is preferable to use a screw for long fibers. Various studies have been conducted on screws for long fibers, and the results of these studies are reported, for example, in Mitsubishi Heavy Industries Technical Report Vol. 34 No. 2 (1997-3). Regarding the MFR of the propylene resin composition, the longer the fiber length of the contained fibers (C) and the higher the content of the flame retardant (B), the lower the MFR tends to be, and the flame resistance also tends to improve. In terms of fiber length, in order to retain more fibers (C) with longer fiber lengths in the propylene resin composition, it is preferable to use an embodiment in which a screw for long fibers is used during melt-kneading. When a general-purpose screw is used, it is often difficult to melt-knead while maintaining the fiber length of the fibers (C), and it may be difficult to obtain the propylene resin composition of the present invention. This melt-mixing process is performed during pellet manufacturing and molding (e.g., injection molding), and it is known that the molding back pressure at this time also affects the fiber length of the fibers (C). To maintain a long fiber length, it is necessary to select an appropriate molding back pressure. That is, if the molding back pressure is too low, the fiber length will be maintained, but the dispersion of the fibers tends to be insufficient. Conversely, if the molding back pressure is too high, it may be difficult to maintain a long fiber length, and the time during which the propylene resin composition is melt-mixed, i.e., the time it is melted and held at a high temperature, will be extended. The molding back pressure that can maintain a long fiber length, minimize the effects of heat on the propylene resin composition during melt-mixing (such as thermal degradation), and ensure good dispersion of the fibers (C) varies depending on the melt-mixing apparatus, and the conditions for obtaining a propylene resin composition with the desired physical properties can be appropriately selected according to the apparatus used. It is also known that the MFR of the propylene resin composition changes depending on the content of the flame retardant (B). For example, a high content of flame retardant (B) tends to lower the MFR of the propylene resin composition, improving its flame-retardant properties. Conversely, a low content of flame retardant (B) tends to increase the MFR of the propylene resin composition, and because there is less flame retardant (B) in it, the flame-retardant properties tend to deteriorate.Here, if the content of the flame retardant (B) is too high, although an improvement in the flame-retardant properties of the propylene resin composition can be expected, the MFR of the propylene resin composition will decrease. As a result, the fibers (C) will break during melt-mixing due to the influence of the flame retardant (B), making it difficult to maintain a long fiber length, and there are concerns about deterioration of various mechanical properties. Conversely, if the content of the flame retardant (B) is too low, the MFR of the propylene resin composition will increase, and as mentioned above, there are concerns about deterioration in flame-retardant properties. In accordance with the provisions of this application, by adjusting the MFR of the propylene resin composition, which changes due to various factors, to the range specified in this application, it is possible to obtain the propylene resin composition of the present invention that exhibits good flame-retardant properties.

[0082] 3. Molding and Uses of Propylene Resin Composition (1) Molding Another aspect of the present invention is a molded article containing the propylene resin composition of the present invention. The propylene resin composition of the present invention can be molded by injection molding (including gas injection molding) or injection compression molding (including press injection, hot flow stamping molding, and gas injection compression molding). Among these, injection molding other than gas injection molding and injection compression molding (press injection) can more effectively obtain the effects of the present invention, and it is preferable to obtain a molded article by such a molding method. In addition, various molding methods such as hollow molding, extrusion molding, compression (press) molding, foam (expansion) molding, sheet molding, thermoforming, stamping molding, and powder molding can be applied as needed to mold the propylene resin composition of the present invention, and a desired molded article (e.g., an extruded article) can be obtained therefrom. Among these, molding methods other than foam (expansion) molding are preferred.

[0083] (2) Applications Examples of applications for molded articles containing the propylene resin composition of the present invention, particularly injection molded articles, include home appliance parts such as rice cookers, vacuum cleaners, washing machines, refrigerators, electric fans, and air conditioners; housings for residential equipment such as vanity units, ventilation fans, toilet seats, toilet lids, and accessories; general battery peripheral components; and battery peripheral components for electric vehicles.

[0084] The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The evaluation methods and materials used in the examples are as follows.

[0085] 1. Evaluation Method 1) Melt Flow Rate (MFR) of Polypropylene Resin (A) The melt flow rate (MFR) of polypropylene resin (A) was measured in accordance with JIS K7210 under conditions of a temperature of 230°C and a load of 2.16 kg.

[0086] 2) Melt flow rate (MFR) of propylene resin composition The melt flow rate (MFR) of the propylene resin composition was measured using a portion of a 170 x 170 mm test piece (thickness: 3.0 mmt) used in the flame-retardant test described later, under conditions of JIS K7210, at a temperature of 230°C and a load of 2.16 kg.

[0087] 3) Evaluation of Flame Resistance Time As described below, evaluation specimens were prepared using two molding machines, (X) and (Y), and the evaluation was performed. (X) Using an injection molding machine [Toshiba EC180, for long fiber screw mounting], a 170 x 170 mm test specimen (thickness: 3.0 mmt) was molded (thickness: 3.0 mmt) with the molding back pressure shown in Table 3 under the conditions of cylinder temperature: 200°C, mold temperature: 40°C, injection pressure: 60 MPa, and injection speed: 60 mm / sec, and the flame resistance test was performed. (Y) Using an injection molding machine [Sumitomo Heavy Industries SE220HD, for general screw mounting], a 170 x 170 mm test specimen (thickness: 3.0 mmt) was molded (thickness: 3.0 mmt) with the molding back pressure shown in Table 3 under the conditions of cylinder temperature: 200°C, mold temperature: 40°C, injection pressure: 60 MPa, and injection speed: 60 mm / sec, and the flame resistance test was performed. The details of the flame resistance test are as follows: A 125 mm flame, used with UL94 5VA, was applied to the flat surface of the test specimen from below. The distance between the test specimen and the burner nozzle was 100 mm. The flame was applied for 15 minutes, and the time at which the flame penetrated (the flame was visually confirmed to be visible from the top of the test specimen) was measured and defined as the flame resistance time for the flame resistance test. If the shape was maintained and the flame did not penetrate for 15 minutes even with continued flame application, the flame application was stopped. The evaluation of the flame resistance time is as follows: ◎: The shape was maintained and the flame did not penetrate during 15 minutes of flame application (indicated as >900) 〇: The shape could not be maintained and the flame penetrated between 10 minutes and 15 minutes △: The shape could not be maintained and the flame penetrated between 5 minutes and 10 minutes ×: The shape could not be maintained and the flame penetrated in less than 5 minutes

[0088] 2. Materials Polypropylene resin (A) (A-1) Novatec PP series, MA1B (propylene homopolymer, MFR: 20 g / 10 min) manufactured by Nippon Polypropylene Co., Ltd. (A-2) Novatec PP series, SA08A (propylene homopolymer, MFR: 75 g / 10 min) manufactured by Nippon Polypropylene Co., Ltd. (A-3) Novatec PP series, MA3 (propylene homopolymer, MFR: 11 g / 10 min) manufactured by Nippon Polypropylene Co., Ltd. (A-4) The MFR of (A-3) above was adjusted with peroxide to obtain (A-4) (propylene homopolymer, MFR: 150 g / 10 min). Organic flame retardant (B) (B-1) FP2500S manufactured by ADEKA Corporation (a phosphorus-based flame retardant containing polyphosphate) Fiber (C) (C-1) Glass fiber: RS2300, 2300TEX manufactured by Nitto Boseki Co., Ltd., fiber diameter 17 μm. Note that this product is in roving form, and the fiber length used in the examples is the same as the pellet length when the fiber masterbatch was prepared. Other additives (D) Other additives (D) used were antioxidants (D-1: Irganox 1010 manufactured by BASF), (D-2: Irgaphos 168 manufactured by ADEKA Corporation), and maleic anhydride-modified polypropylene (D-3: OREVAC CA100 manufactured by Arkema).

[0089] 3. Preparation of various masterbatches (MB) 1) Flame retardant masterbatch: Preparation of flame retardant MB-I and II Polypropylene resin (A), phosphorus-based flame retardant (B), and other additives (D) were blended in the proportions shown in Table 1 and mixed for 3 minutes at room temperature using a high-speed agitator mixer (Henschel mixer, trade name). Then, the mixture was melt-kneaded and extruded using a twin-screw extruder, passed through a cold water bath, and the strands were cut with a strand cutter to obtain flame retardant masterbatch pellets.

[0090]

[0091] 2) Fiber Masterbatch: Preparation of Fiber MB-I Fiber MB-I was prepared by introducing fiber bundles of glass fibers (C) from a fiber rack into a resin impregnation tank of polypropylene resin heated to 270°C, impregnating the glass fiber bundles with polypropylene resin, then withdrawing them through a circular nozzle in the impregnation tank, cooling, and cutting to obtain fiber MB-I pellets. The length of the obtained fiber MB-I pellets was 10 mm. The weight ratio of polypropylene resin to glass fiber for each fiber MB was as shown in Table 2. In this process, 0.1 parts by weight of D-1, 0.05 parts by weight of D-2, and 0.4 parts by weight of D-3 were added per 100 parts by weight of polypropylene resin in the impregnation tank.

[0092]

[0093] 4. Preparation of Test Specimens 1) Examples 1-3 Comparative Examples 1-5 The obtained masterbatches and polypropylene resin (A) were mixed in the ratios shown in the dry blend ratio column of Table 3, and then molded using an injection molding machine. The samples were evaluated according to the evaluation method described above. The evaluation results are shown in Table 3.

[0094]

[0095] 5. Evaluation Results As shown in Table 3, it can be seen that, at a given glass fiber concentration and flame retardant amount, a propylene-based resin composition exhibits high flame resistance if its melt flow rate is 9 or less. Specifically, although Example 1 and Comparative Examples 1 and 4 use the same raw materials, their composition, molding machine, and molding conditions differ, resulting in different melt flow rates for the propylene-based resin compositions. This changes the shape retention of the propylene-based resin composition when exposed to flame, leading to significant differences in flame resistance. The reasons for the difference in melt flow rate are thought to be the change in residual fiber length depending on the molding machine and molding conditions, as well as the content of flame retardant (B). Focusing particularly on residual fiber length, the propylene-based resin composition obtained by the manufacturing method of Example 1, which is assumed to have a longer residual fiber length, has the lowest melt flow rate and the highest flame resistance. The same can be seen when comparing Example 2 and Comparative Example 2, and Example 3 and Comparative Examples 3 and 5.

[0096] From these examples and comparative examples, it is clear that in order to achieve the high level of flame-retardant properties required in this application, the resin composition and MFR of the propylene-based resin composition as defined in the claims of this application are necessary.

Claims

1. A propylene resin composition characterized by containing a polypropylene resin (A) that satisfies the following requirement (A1), a flame retardant (B) that satisfies the following requirement (B1), and a fiber (C) that satisfies the following requirement (C1), and satisfying the following conditions 1 and 2. Requirement (A1) The polypropylene resin (A) contains at least one propylene polymer selected from the group consisting of propylene homopolymer, propylene random copolymer, and propylene block copolymer. Requirement (B1) The flame retardant (B) is an organic flame retardant. Requirement (C1) The fiber (C) is a glass fiber with a fiber length of 1 mm or more and 20 mm or less. Condition 1: The propylene resin composition contains 20-70% by weight of polypropylene resin (A), 15-30% by weight of flame retardant (B), and 15-50% by weight of fiber (C) (however, the total of polypropylene resin (A), flame retardant (B), and fiber (C) is 100% by weight). Condition 2: The melt flow rate (MFR, 230°C, 2.16 kg load) of the propylene resin composition is 9 g / 10 min or less.

2. The propylene resin composition according to claim 1, wherein the polypropylene resin (A) further satisfies the following requirement (A2): Requirement (A2) The polypropylene resin (A) comprises at least two types of polypropylene resins (Aa) and polypropylene resin (Ab), and the melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene resin (Aa) is in the range of 60 to 2000 g / 10 min.

3. The propylene resin composition according to claim 1, wherein the flame retardant (B) is a phosphorus-based flame retardant.

4. The propylene resin composition according to claim 3, wherein the flame retardant (B) is a polyphosphate salt.

5. A molded article comprising the propylene resin composition according to any one of claims 1 to 4.

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