Polypropylene resin composition

Abstract

High flame retardancy of polypropylene materials by compounding them with phosphorus-based flame retardants. [Solution] A propylene resin composition that satisfies conditions 1 and 2, comprising a polypropylene resin (A) that satisfies requirement (A1) containing at least one propylene polymer selected from the group consisting of propylene homopolymer, propylene random copolymer and propylene block copolymer; a flame retardant (B) that satisfies requirement (B1) being an organic flame retardant; and a fiber (C) that satisfies requirement (C1) being a glass fiber with a fiber length of 1 mm or more and 20 mm or less. Condition 1: The propylene resin composition contains 20-80% by weight of (A), 5-30% by weight of (B), and 15-50% by weight of (C). Condition 2: The remaining fiber length (LD99.9) and the concentration of fiber (C) of the propylene resin composition satisfy the following formula (1). Formula (1): LD99.9≧-0.03×Cconc.+4.2

Description

[Technical Field]

[0001] The present invention relates to a polypropylene resin composition. More specifically, it relates to a polypropylene resin composition with excellent flame-retardant properties containing a phosphorus-based flame retardant and glass fibers. [Background technology]

[0002] Polyolefin resins, leveraging their superior chemical and mechanical properties, are widely used in various fields such as building materials, automotive parts, packaging materials, and home appliances, and their applications are expanding. However, many polyolefin resins are flammable, and flame retardancy is necessary depending on the application. A method that has been widely used for flame retardancy in the past is a system that combines a brominated flame retardant with antimony trioxide, a flame retardant enhancer.

[0003] However, flame retardation methods using bromine-based flame retardants have poor shape retention due to their material properties, making it difficult to withstand prolonged exposure to flames. In contrast, flame retardation methods using phosphorus-based flame retardants, particularly those that form carbonaceous char after combustion, can achieve fire resistance by carbonizing the flame-contacting surface, and are expected to withstand relatively long periods of exposure to flames.

[0004] On the other hand, in the case of materials using phosphorus-based flame retardants, such as those described in Patent Documents 1 and 2, while studies on oxygen index and self-extinguishing properties, such as UL94 V tests, have been conducted extensively, there have been few examples of in-depth studies on fire resistance performance.

[0005] In recent years, studies such as that described in Patent Document 3 have been reported, which examine the fire resistance performance of test specimens made by combining phosphorus-based flame retardants with glass fibers.

[0006] However, the flame exposure time of the technology disclosed in Patent Document 3 is not sufficient. For example, the Chinese GB / T 38031-2020 standard specifies that, assuming an EV vehicle fire, "no smoke / flames should be emitted outside the battery pack for 5 minutes after the battery cells ignite while the battery pack is in its state," but the invention in Patent Document 3 does not discuss fire resistance performance of 5 minutes or more. In other words, it is clear that the problem of providing a material that exhibits the performance to withstand prolonged flame exposure, which will be required by society in the future, still remains. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 4753498 [Patent Document 2] Patent No. 5462584 [Patent Document 3] Japanese Patent Publication No. 7329528 [Overview of the project] [Problems that the invention aims to solve]

[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. [Means for solving the problem]

[0009] To solve the above problems, this invention was developed through diligent research, resulting in the formulation of a polypropylene resin with a specific flame retardant and specific fibers in specific proportions, and furthermore, the remaining fiber length (L) of the propylene resin composition. D99.9 We discovered that the resulting polypropylene resin composition can solve the above problems by ensuring that the concentration of the fibers satisfies a specific relationship, and based on these findings, we completed the present invention.

[0010] In other words, the present invention has the following configuration. [1] A polypropylene resin (A) satisfying the following requirement (A1), a flame retardant (B) satisfying the following requirement (B1), and a fiber (C) satisfying the following requirement (C1), and satisfying the following Conditions 1 and 2. A propylene resin composition characterized by the above. Requirement (A1) The polypropylene resin (A) contains at least one propylene polymer selected from the group consisting of a propylene homopolymer, a propylene random copolymer, and a propylene block copolymer. Requirement (B1) The flame retardant (B) is an organic flame retardant. Requirement (C1) The fiber (C) is a glass fiber, and a fiber having a fiber length of 1 mm or more and 20 mm or less is used. Condition 1 The propylene resin composition contains 20 to 80% by weight of the polypropylene resin (A), 5 to 30% by weight of the flame retardant (B), and 15 to 50% by weight of the fiber (C) (however, the total of the polypropylene resin (A), the flame retardant (B), and the fiber (C) is 100% by weight). Condition 2 The residual fiber length (L D99.9 ) and the concentration (C conc. ) of the fiber (C) satisfy the following formula (1). Formula (1): L D99.9 ≧ -0.03×C conc. + 4.2 [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 polypropylene resins (Aa) and a 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] or [2], wherein the flame retardant (B) is a phosphorus-based flame retardant. [4] A propylene resin composition according to [3], wherein the flame retardant (B) is a polyphosphate. [5] A molded article comprising a propylene resin composition as described in any one of items [1] to [4]. [Effects of the Invention]

[0011] The present invention makes it possible to provide a material with excellent flame-retardant properties that can withstand prolonged exposure to flames. [Brief explanation of the drawing]

[0012] [Figure 1] The fiber concentration (Cconc.) and remaining fiber length (LD99.9) of the examples and comparative examples are plotted on a graph, and the line shown is represented by the relationship formula defined in the claims of this application. Embodiments for carrying out the invention

[0013] 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. Requirements (A1) The polypropylene resin (A) contains at least one propylene polymer selected from the group consisting of propylene homopolymers, propylene random copolymers, and propylene block copolymers. Requirements (B1) Flame retardant (B) is an organic flame retardant. Requirements (C1) Fiber (C) is a glass fiber with a fiber length of 1 mm to 20 mm. Condition 1 The propylene resin composition contains 20-80% by weight of polypropylene resin (A), 5-30% 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 remaining fiber length (L) of the propylene resin compositionD99.9 ) and the concentration (C conc. ) of the fiber (C) satisfy the following formula (1). Formula (1): L D99.9 ≧ -0.03 × C conc. + 4.2

[0014] Hereinafter, the details of each item of the propylene-based resin composition of the present invention will be described.

[0015] 1. Propylene-based resin composition The propylene-based resin composition of the present invention satisfies the following Condition 1.

[0016] Condition 1 The propylene-based resin composition contains 20 to 80% by weight of a polypropylene-based resin (A), 5 to 30% by weight of a flame retardant (B), and 15 to 50% by weight of a fiber (C) (however, the total of the polypropylene-based resin (A), the flame retardant (B), and the fiber (C) is 100% by weight). Details of the polypropylene-based resin (A), the flame retardant (B), and the fiber (C) will be described later.

[0017] The propylene-based resin composition of the present invention needs to contain 20 to 80% by weight of the polypropylene-based resin (A), preferably 26 to 74% by weight, more preferably 32 to 68% by weight, and still more preferably 38 to 62% by weight. The flame retardant (B) needs to contain 5 to 30% by weight, preferably 6 to 29% by weight, more preferably 7 to 28% by weight, and still more preferably 8 to 27% by weight. The fiber (C) needs to contain 15 to 50% by weight, preferably 20 to 45% by weight, more preferably 25 to 40% by weight, and still more preferably 30 to 35% by weight. By setting the contents of the polypropylene-based resin (A), the flame retardant (B), and the fiber (C) within such ranges, it becomes possible to provide a material that can achieve both flame shielding properties that can withstand long-term flame contact and excellent fluidity in moldability. That is, if the flame retardant (B) and the fiber (C) are too much, although the flame shielding property is improved, the fluidity deteriorates and the moldability tends to decrease. Conversely, if the flame retardant (B) and the fiber (C) are too little, sufficient flame shielding properties may not be obtained.

[0018] The propylene-based resin composition of the present invention further satisfies the following condition 2.

[0019] Condition 2 The remaining fiber length (L) of the propylene resin composition D99.9 ) and the concentration of fiber (C) conc. ) and satisfy the following equation (1). Formula (1):L D99.9 ≥-0.03 × C conc. +4.2

[0020] The remaining fiber length (L) in the present invention D99.9 The measurement method for the remaining fiber length (L) was carried out in accordance with the content described in paragraphs

[0022] to

[0027] of Japanese Patent Publication No. 2021-181908. Of the samples measured at that time, the value of the fiber length that is the 99.9th in length when counting from the shortest remaining fiber length (for example, if 1000 samples were measured, the value of the 999th fiber when counting from the shortest) was used as the remaining fiber length (L). D99.9 ) was defined as follows. In the present invention, the longer the remaining fiber length, the better the flame-retardant properties can be achieved, so it is preferable to measure and evaluate the remaining fiber length of the longest possible fibers. However, if the evaluation is based on all glass fibers as the remaining fiber length, i.e., if the maximum value is used for evaluation, if there are long fibers that happen to remain without breaking during kneading, the evaluation result of the remaining fiber length will be affected by those long fibers that happen to remain, and it may be difficult to make an accurate evaluation. In this application, the remaining fiber length is defined as the remaining fiber length (L D99.9 The reason for using (C) is to eliminate cases where accurate evaluation becomes difficult due to the influence of residual fibers that remain by chance. Regarding the flame-retardant properties of propylene resin compositions, the fiber concentration (C) of the propylene resin composition is used. conc. The higher the remaining fiber length (L), the better. D99.9It has been found that the larger the value of ), the better the flame-retardant properties. Furthermore, fiber concentration and remaining fiber length can complement each other's performance; for example, even with a low fiber concentration, good flame-retardant properties can be maintained if the remaining fiber length is long, and conversely, if the fiber concentration is high, good flame-retardant properties can be maintained even with a short remaining fiber length. Equation (1) is an equation empirically derived from the values ​​of the present invention's examples and comparative examples and Figure 1, describing the above phenomenon.

[0021] The melt flow rate (MFR, 230°C, 2.16 kg load) of the propylene resin composition is preferably 9 g / 10 min or less. In the present invention, sufficient flame-retardant properties can be achieved by setting the melt flow rate of the propylene-based resin composition to 9 g / 10 min or less. The melt flow rate of the propylene-based resin composition is preferably 1 to 8 g / 10 min, more preferably 2 to 7 g / 10 min. Furthermore, the melt flow rate of a propylene-based 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).

[0022] (1) Polypropylene resin (A) The details of the polypropylene resin (A) used in the present invention are described below.

[0023] Requirements (A1) The polypropylene resin (A) used in the present invention comprises at least one propylene polymer selected from the group consisting of propylene homopolymers, propylene random copolymers, and propylene block copolymers. As the propylene random copolymer, a propylene-α-olefin random copolymer is preferred. As the propylene block copolymer, a propylene-α-olefin block copolymer is preferred. Hereinafter, in this specification, propylene-α-olefin block copolymers and propylene-α-olefin random copolymers may be simply referred to as "propylene-α-olefin copolymers". 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 different random copolymers or block copolymers of α-olefins may also be used.

[0024] Furthermore, the comonomer, which is an α-olefin with 2 to 8 carbon atoms excluding propylene, may be used alone or in combination of two or more types. 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, and 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.

[0025] Examples of α-olefins having 2 to 8 carbon atoms, excluding 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-olefin as a comonomer in the propylene-α-olefin copolymer in the above-mentioned amount, it is possible to maximize the effects of the propylene-based resin composition of the present invention.

[0026] Here, the propylene, ethylene, and α-olefins having 4 to 8 carbon atoms (hereinafter sometimes abbreviated as "the monomers") that are comonomers of the polypropylene resin (A) may be manufactured from biomass or derived from chemical recycling. The comonomers of the polypropylene resin (A), such as propylene, ethylene, and α-olefins having 4 to 8 carbon atoms, may consist solely of biomass-derived monomers or solely of fossil fuel-derived monomers. Alternatively, both biomass-derived and fossil fuel-derived monomers may be included. Furthermore, the comonomers of the polypropylene resin (A), such as propylene, ethylene, and α-olefins having 4 to 8 carbon atoms, may consist solely of monomers derived from chemical recycling, or solely of monomers derived from fossil fuels. Alternatively, both monomers derived from chemical recycling and monomers 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.

[0027] 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, such as those derived from discarded automobiles, battery cases, home appliances, contact lens polymerization types, and logistics materials, as long as it does not impede the effects of the present invention. It is also possible to mix these recycled resins with the aforementioned monomers derived from biomass, chemical recycling, and fossil fuels in any ratio.

[0028] 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).

[0029] 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) falls below 1 g / 10 min, the load when molding the propylene-based resin composition of the present invention increases, which may worsen moldability and cause discoloration of the molded article, resulting in a poor appearance. Conversely, if it exceeds 200 g / 10 min, it may reduce flame resistance and fire retardancy, and impair scratch resistance and flexural strength. Furthermore, if the polypropylene resin (A) contains two or more types of propylene polymers, any of these two or more propylene polymers may have a melt flow rate (MFR) within the range described above, or even if some or all of the two or more propylene polymers have a melt flow rate (MFR) outside the range described above, the polypropylene resin (A) as a whole may have a melt flow rate (MFR) within the range described above.

[0030] Furthermore, in the present invention, the polypropylene resin (A) having an isotactic pentad fraction (mmmm fraction) of 96% or higher, which indicates its degree of crystallinity, is preferably used, and more preferably has an isotactic pentad fraction of 97% or higher. When the isotactic pentad fraction is 96% or higher, good flame resistance can be obtained in the propylene resin composition of the present invention, and various mechanical properties, such as scratch resistance and flexural strength, are also good, which is preferable. The detailed reason for this is not clear, but 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 by controlling the copolymerization ratio of the raw materials and the catalyst used. The above isotactic pentad fraction (mmmm) is, 13 This value is measured using 1C-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 1C-NMR. That is, 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 1C-NMR spectrum, for example, using a 270MHz FT-NMR instrument manufactured by JEOL Ltd.

[0031] The catalyst used to obtain the polypropylene resin (A) used in the present invention is not particularly limited, and any known catalyst can be used. For example, a so-called Ziegler-Natta catalyst, which combines a titanium compound and organoaluminum (as described in, for example, the Polypropylene Handbook (first edition, first printing, May 15, 1998)), or a metallocene catalyst (as described in, for example, Japanese Patent Publication No. 5-295022) can be used.

[0032] 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. Furthermore, 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, such as 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.

[0033] The polypropylene resin (A) used in the present invention preferably further satisfies the following requirement (A2). Requirements (A2) The polypropylene resin (A) contains 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. The melt flow rates (MFRs) of at least two polypropylene resins (Aa) and polypropylene resin (Ab) may be the same or different, but it is preferable that the melt flow rate (MFR) of polypropylene resin (Aa) is greater than that of polypropylene resin (Ab) because it makes it easier to set the melt flow rate (MFR) of 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℃, 2.16kg 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 kneading operation is also simple.

[0034] 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 most 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 polypropylene resin (A) described above. As stated above, it is preferable that the melt flow rate (MFR) of polypropylene resin (Aa) is greater than that of polypropylene resin (Ab). In this specification, the melt flow rate (MFR) is 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 is hereafter referred to as MFR. A It is sometimes abbreviated as such. 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)

[0035] The types of polypropylene resins (Aa) and polypropylene resins (Ab) (i.e., the types of propylene polymers), preferred melting points, and preferred isotactic pentad fractions are as detailed for polypropylene resin (A). Furthermore, the polypropylene resin (Ab) may contain two or more types.

[0036] 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). In other words, as mentioned above, in the present invention, it is important to set the melt flow rate (MFR) of polypropylene resin (A) within a desired range and adjust the content of flame retardant (B) within that desired range to a specific range.

[0037] 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), provided that the effects of the present invention are not hindered.

[0038] 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.

[0039] (2) Flame retardant (B) The details of the flame retardant (B) used in the present invention are described below.

[0040] Requirements (B1) The flame retardant (B) used in the present invention is an organic flame retardant. Typically, inorganic flame retardants require a larger additive amount to achieve the desired level of flame retardancy, and achieving a high level of flame retardancy results in a higher specific gravity. In contrast, organic flame retardants can exhibit flame retardancy with relatively low additive amounts, making it possible to achieve a high level of flame retardancy with a relatively low specific gravity. Therefore, in this invention, it is necessary to use an organic flame retardant as flame retardant (B).

[0041] 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 compounds can be used. However, phosphorus-based flame retardants are preferred because they tend to exhibit good flame-retardant properties in the propylene-based resin composition of the present invention.

[0042] As phosphorus-based flame retardants, any that are commonly used as flame retardants for polyolefins can be used. Examples include various substituted or modified compounds such as trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, tricyclohexyl phosphate, trixyneyl phosphate, cresyl diphenyl phosphate, dicresyl phenyl phosphate, dimethyl ethyl phosphate, trixyneyl phosphate, methyl dibutyl phosphate, ethyl dipropyl phosphate, hydroxyphenyl diphenyl phosphate, phosphate compounds, phosphazene derivatives containing phosphorus and nitrogen, and other compounds or mixtures. These phosphorus-based flame retardants may be used individually or in combination of two or more types.

[0043] Furthermore, in one preferred embodiment of the present invention, the phosphorus-based flame retardant is a polyphosphate. When a polyphosphate is used as an organic flame retardant, it forms an intomescent layer during combustion, making it suitable for flame-retardant properties. Examples of polyphosphates include phosphates such as those described in paragraphs

[0015] to

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

[0044] In addition, other organic flame retardants that do not fall under the category of phosphorus-based flame retardants, such as halogenated or nitrogen-based flame retardants, can also be used along with phosphorus-based flame retardants.

[0045] As halogenated flame retardants, organic halogenated aromatic compounds such as halogenated diphenyl compounds, halogenated bisphenol compounds, halogenated bisphenol-bis(alkyl ether) compounds, and halogenated phthalimide compounds are preferred, with halogenated bisphenol-bis(alkyl ether) compounds being particularly preferred. Examples of the above-mentioned halogenated diphenyl compounds include halogenated diphenyl ether compounds, halogenated diphenyl ketone compounds, and halogenated diphenylalkane compounds, among which halogenated diphenylalkane compounds such as decabromodiphenylethane are preferred.

[0046] Examples of the above-mentioned halogenated bisphenol compounds include halogenated bisphenylalkanes, halogenated bisphenyl ethers, halogenated bisphenyl thioethers, and halogenated bisphenylsulfones, among which halogenated bisphenyl thioethers such as bis(3,5-dibromo-4-hydroxyphenyl)sulfone are preferred.

[0047] 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-4-2,3-dibromopropoxyphenyl)propane, bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl)propane, bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl)propane, (3,5-dibromo-4-2,3-dibromopropoxyphenyl)propane, (3,5-dibromo-4-2,3-dibromopropoxyphenyl)propane, (3,5-dibromo-4-2,3-dibromopropoxyphenyl)propane, (3,5-dichloro Romopropoxyphenyl)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) (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 (brominated aliphatic ether), tetrabromobisphenol 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.

[0048] 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 halogen-based flame retardants, bromine-based 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 manufacturing and molding of the polypropylene resin composition of the present invention.

[0049] 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 Examples of 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.

[0050] When phosphorus-based flame retardants are used in combination with various organic flame retardants such as halogenated and nitrogen compounds, the organic flame retardants may be used alone or in combination of two or more types. For example, phosphorus-based flame retardants can be used in combination with organic halogenated flame retardants and nitrogen compounds. Furthermore, as described above, it can also be used in the form of a so-called masterbatch, which is a relatively high concentration of the polypropylene resin (A) or the like that has been prepared in advance.

[0051] (3) Fibers (C) The details of the fiber (C) used in the present invention are described below.

[0052] Requirements (C1) Fiber (C) is a glass fiber with a fiber length of 1 mm to 20 mm. Fiber (C) not only improves physical properties such as rigidity and impact strength in the propylene-based resin composition and molded articles containing the same according to 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.

[0053] (3-1) Types and manufacturing methods of glass fiber As described above, fiber (C) is glass fiber. Using glass fiber as fiber (C) is preferable in terms of ease of manufacture and cost-effectiveness, as it allows for good flame resistance in the propylene-based resin composition and molded articles containing the same according to the present invention. To further improve the effects of the present invention, two or more types of this fiber (C) can be used in combination, and as described above, it can also be used in the form of a so-called masterbatch in which it is previously contained in the polypropylene resin (A) or the like at a relatively high concentration. Furthermore, materials that do not fall under the category of fibers (C), such as glass beads, glass balloons, mica, and various inorganic or organic fillers that do not fall under the category of fibers (C), can also be used in combination within a range that does not significantly impair the effects of the present invention.

[0054] 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 method for manufacturing the glass fibers is not particularly limited, and any glass fibers manufactured by various known manufacturing methods can be used. Therefore, a desired product can be selected from a variety of commercially available products.

[0055] The fiber diameter of the glass fiber 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 fiber within this range, dispersion in the polypropylene resin is improved, while the glass fiber is less prone to breakage, resulting in good 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 manufacturing and molding of the propylene-based resin composition and molded articles containing the same according to the present invention. On the other hand, if the fiber diameter exceeds 25 μm, the aspect ratio of the fibers decreases, which may reduce the flame-retardant properties, rigidity, and impact strength of the propylene-based resin composition and molded articles containing the same according to the present invention.

[0056] 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).

[0057] 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 aggregation of multiple continuous glass fibers, or pellets manufactured by the so-called plutrusion method. In such cases, roving-like materials are usually used. Furthermore, two or more types of glass fibers can be used in combination.

[0058] The fiber length is 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." Therefore, the length of the pellet may be used as the glass fiber length. The fiber diameter is determined from values ​​measured using a microscope or calipers.

[0059] 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 their dispersibility in polypropylene resin (A). Examples of organic silane coupling agents used in 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.

[0060] 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 is preferably 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.

[0061] 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 the melt-kneading process with the polypropylene resin (A), it is preferable that they melt at a temperature of 200°C or lower.

[0062] 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).

[0063] 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 products 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.

[0064] 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 hardly causes any breakage of the fibers.

[0065] 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 fibers 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, even 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 become 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-retardant and flame-blocking properties. Furthermore, in the glass fiber-containing pellets, the glass fiber content 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 becomes possible to improve the flame resistance, 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 made therefrom. Specifically, 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 resin composition of the present invention and the molded articles made therefrom may decrease. On the other hand, if a content of 70% by weight or more is used, moldability (fluidity) and other properties may decrease.

[0066] (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 typically 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 regulators, foaming agents, pigments, ultraviolet absorbers, antioxidants, antistatic agents, neutralizing agents, metal deactivators, stabilizers, antibacterial agents, inorganic fillers, and rubbery components.

[0067] 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-di-methyl-2,5-di-(benzoylperoxy)hexane, 2,5-di-methyl-2,5-di-(benzoylperoxy)hexine-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-di-methyl-2,5-di-(t-butylperoxy)hexane, 2,5-di-methyl-2,5-di-(t-butylperoxy)hexine-3, 1,3-bis-(t-butylperoxyisopropyl)benzene, t-butylquyl 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, di-isopropylbenzene 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.

[0068] 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. Furthermore, 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 these, 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.

[0069] 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 bubble regulator, it is preferable that the amount of the bubble regulator added be 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 decomposable blowing agents (chemical blowing agents) include mixtures of sodium bicarbonate and organic acids such as citric acid, azo-based blowing agents such as azodicarbonamide and barium azodicarboxylate, nitroso-based blowing agents such as N,N'-dinitrosopentamethylenetetramine and N,N'-dimethyl-N,N'-dinitrosotelephthalamide, sulfohydrazide-based blowing 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.

[0070] Furthermore, either known organic pigments or inorganic pigments can be used as the pigment. Specifically, these 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.

[0071] 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-butylphenyl 3',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. Two or more of these may also be used in mixture form.

[0072] 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.

[0073] 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.

[0074] In particular, as antistatic agents, cationic, anionic, nonionic, and amphoteric ionic agents, as well as fatty acid partial esters such as glycerol 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.

[0075] Suitable nucleating agents include 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, and talc. 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 materials include sodium bis(4-t-butylphenyl) phosphate, sodium 2,2'-ethylidene-bis(4,6-di-t-butylphenyl) phosphate, and organic phosphate composites. Other examples include sodium benzoate, aluminum pt-butylbenzoate, sodium montana, calcium montana, aluminum oxide, kaolin clay, talc, rosins, and petroleum resins. Two or more of these may be used in combination.

[0076] Examples of metal deactivators that can be used include triazines, phosphones, epoxys, triazoles, hydrazides, and oxamides. Specifically, examples 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.

[0077] 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 26-300, 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.

[0078] 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.

[0079] Furthermore, specific examples of inorganic fillers include talc, barium sulfate, clay, silica, calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, glass fiber, and whiskers.

[0080] 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.

[0081] 2. Method for preparing a propylene-based resin composition Examples of methods for preparing the propylene resin composition of the present invention include: 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); 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; 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).

[0082] The polypropylene resin composition of the present invention can be obtained by any of the above methods. When using these methods, known mixing methods such as tumbler mixers, super mixers, Henschel mixers, screw blenders, and ribbon blenders can be applied. 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.

[0083] 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 a propylene-based resin composition, the longer the fiber length of the contained fiber (C), the lower the MFR tends to be, and the improved flame resistance also tends to be. To retain more longer fiber (C) in the propylene-based resin composition, an embodiment using a screw for long fibers is preferred. When a general-purpose screw is used, it is often difficult to melt-knead the material while maintaining the long fiber length of the fiber (C), which may make it difficult to obtain the propylene-based 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. On the other hand, 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 prolonged. 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.

[0084] 3. Molding and applications of propylene resin compositions (1) Molding Another aspect of the present invention is a molded article comprising the propylene-based 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, 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 the molded article by such a molding method. The propylene-based resin composition of the present invention can also be molded using various molding methods as needed, such as hollow molding, extrusion molding, compression (press) molding, foam (expansion) molding, sheet molding, thermoforming, stamping molding, and powder molding, thereby obtaining a desired molded article (e.g., an extruded article). Among these, molding methods other than foam (expansion) molding are preferred.

[0085] (2)Applications Applications of molded articles, particularly injection-molded articles, obtained from the propylene resin composition of the present invention include, for example, 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. [Examples]

[0086] 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.

[0087] 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 230°C and a 2.16 kg load.

[0088] 2) Remaining fiber length (L D99.9 ) measurement 2)-1 Sample preparation Using an injection molding machine [Toshiba EC180, equipped with a screw for long fibers], a 170 x 170 mm test specimen (thickness: 3.0 mmt) was molded with the molding back pressure shown in Table 3 under the following conditions: cylinder temperature: 200°C, mold temperature: 40°C, injection pressure: 60 MPa, injection speed: 60 mm / sec. A 15 mm x 15 mm sample was then cut from the center. 2)-2 Measurement Using a MicroCT-50 manufactured by SCANCO, the sample obtained in 2)-1 was set in a dedicated measurement folder, and 3D image data with a resolution of 6.0 μm per voxel was obtained for a range corresponding to 1 / 3 of the total thickness of the sample, using an X-ray tube output of 55 kV, 44 mA (4 W). The tilt of the obtained image data was corrected using the AlignZ function of the image processing software (SCANCO, μCT V6.1) included with the instrument. Then, the contrast threshold was visually set to 3500 using the Fiber Tracking function of the image processing software (SCANCO, μCT V6.1) included with the instrument, and a grayscale image was obtained. The fiber length was measured from this image using the Fiber Tracking function, and the remaining fiber length (L) was determined. D99.9 ) was obtained. In this example, the measurement was performed twice (n2), and the results of the first measurement (N1) and the second measurement (N2) are shown in Table 3. Also, the remaining fiber length (L D99.9 The evaluation of ) was based on the average value obtained from these two measurements.

[0089] 2) Evaluation of flame resistance time As described below, evaluation specimens were prepared using an injection molding machine and evaluated. The remaining fiber length (L) D99.9 Using the same injection molding conditions as those used to prepare the measurement samples, namely the injection molding machine [Toshiba EC180, with long-fiber screw mounting], a 170 x 170 mm test piece (thickness: 3.0 mmt) was molded under the molding back pressure shown in Table 3, with a cylinder temperature of 200°C, mold temperature of 40°C, injection pressure of 60 MPa, and injection speed of 60 mm / sec, and the flame-retardant test was performed. The details of the flame-retardant properties test are as follows. A 125mm flame, as used in 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 100mm. The flame was maintained for 15 minutes, and the time at which the flame penetrated (visually visible from the top of the test specimen) was measured and defined as the flame resistance time for the flame resistance test. If the specimen maintained its shape and the flame did not penetrate for 15 minutes, the flame application was stopped. The evaluation of the flame resistance time is as follows: ◎: Maintains its shape even after 15 minutes of flame exposure, and the flame does not penetrate it (indicated as >900) 〇: Between 10 and 15 minutes, the shape could no longer be maintained, and flames penetrated it. △: The shape was lost between 5 and 10 minutes, and flames penetrated it. ×: The shape was lost in less than 5 minutes, and the flames penetrated it.

[0090] 2.Material Polypropylene resin (A) (A-1) Novatec PP series, MA1B (propylene homopolymer, MFR: 20g / 10 min), manufactured by Nippon Polypropylene Co., Ltd. (A-2) Nippon Polypropylene Co., Ltd., Novatec PP series, SA08A (propylene only heavy Combined, MFR: 75g / 10 mins) (A-3) Novatec PP series, MA3 (propylene homopolymer, MFR: 11g / 10 min), manufactured by Nippon Polypropylene Co., Ltd. (A-4) The above (A-3) was prepared using a peroxide to adjust the MFR, and used as (A-4) (propylene homopolymer, MFR: 150g / 10min). Organic flame retardant (B) (B-1) ADEKA Corporation, FP2500S (a phosphorus-based flame retardant containing polyphosphate) Fiber (C) (C-1) Glass fiber: Manufactured by Nitto Boseki Co., Ltd., RS2300, 2300TEX, 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 used when preparing the fiber masterbatch. Other additives (D) Other additives (D) used included 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).

[0091] 3. Creation of various masterbatches (MBs) 1) Flame-retardant masterbatch: Preparation of flame-retardant MB-I and MB-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). The mixture was then 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.

[0092] [Table 1]

[0093] 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 the 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 MFR of the polypropylene resin in the impregnation tank and the weight ratio of polypropylene resin to glass fiber in each fiber MB are 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.

[0094] [Table 2]

[0095] 4. Preparation of test specimens 1) Examples 1-3, Comparative Examples 1-3 The obtained masterbatches and polypropylene resin (A) were mixed in the ratios shown in the dry blend ratio column of Table 3, then molded using an injection molding machine, and evaluated according to the evaluation method described above. The evaluation results are shown in Table 3.

[0096] [Table 3]

[0097] 5. Evaluation Results From the results shown in Table 3, at a given glass fiber concentration and flame retardant amount of propylene resin composition, the remaining fiber length (L) of the propylene resin composition is determined. D99.9 ) and the concentration of fiber (C) conc. If ) satisfies formula (1), it can be seen that it has a high degree of flame-retardant properties. To give a specific example, Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Example 3 and Comparative Example 3 all use the same raw materials and final composition, but in this example, the molding conditions of the molding machine used for melt kneading, particularly the molding back pressure, differ, resulting in a difference in the remaining fiber length (L) of the propylene resin composition. D99.9 ) differ, which results in a significant difference in flame-retardant properties. In other words, in Examples 1-3, where the molding back pressure is low, the remaining fiber length (L) of the propylene resin composition differs. D99.9 Since the remaining fiber length (L) is long, it satisfies formula (1) and also has high flame-retardant properties. On the other hand, Comparative Examples 1 to 3 are propylene resin compositions with a remaining fiber length (L) D99.9 Since the ratio is short and does not satisfy formula (1), the flame-retardant properties are low and insufficient.

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. Requirements (A1) The polypropylene resin (A) contains at least one propylene polymer selected from the group consisting of propylene homopolymers, propylene random copolymers, and propylene block copolymers. Requirements (B1) Flame retardant (B) is an organic flame retardant. Requirements (C1) Fiber (C) is a glass fiber with a fiber length of 1 mm to 20 mm. Condition 1 The propylene resin composition contains 20 to 80% by weight of polypropylene resin (A), 5 to 30% by weight of flame retardant (B), and 15 to 50% by weight of fiber (C) (provided that the total of polypropylene resin (A), flame retardant (B), and fiber (C) is 100% by weight). Condition 2 The remaining fiber length (L) of the propylene resin composition Ｄ９９．９ ) and the concentration of fiber (C) (C ｃｏｎｃ． ) and satisfy the following equation (1). Equation (1): L Ｄ９９．９ ≧-0.03×C ｃｏｎｃ． +4.2

2. The propylene resin composition according to claim 1, wherein the polypropylene resin (A) further satisfies the following requirement (A2). Requirements (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.

Images