Polypropylene resin composition

Abstract

[Problem] To provide a material having good fluidity for excellent moldability and having flame resistance and flame retardancy for withstanding contact with flames over a long period. [Solution] Provided is a polypropylene resin composition characterized by: comprising a polypropylene resin (A) satisfying requirement (A1), a flame retardant satisfying requirement (B1), and fibers (C) satisfying requirement (C1); and by satisfying condition 1 and condition 2.

Description

Polypropylene resin composition

[0001] The present invention relates to a polypropylene resin composition, and more particularly to a polypropylene resin composition containing a phosphorus-based flame retardant and glass fibers and having excellent fire resistance and flame barrier properties.

[0002] Taking advantage of their superior chemical and mechanical properties, polyolefin resins are widely used in a variety of fields, including building materials, automobile parts, packaging materials, and home appliances, and their applications are expanding. However, many polyolefin resins are flammable, and flame retardancy is required for some applications. A widely used flame retardant method has traditionally been a combination of a bromine-based flame retardant and antimony trioxide, a flame retardant promoter.

[0003] However, flame retardant methods using bromine-based flame retardants have poor shape retention when softened by heat due to their material properties, making it difficult to withstand prolonged flame contact.In contrast, flame retardant methods using phosphorus-based flame retardants, especially those that form carbonaceous char after combustion, carbonize the flame-contact surface and retain their shape, making them fire-resistant and flame-blocking, and are expected to be able to withstand relatively long periods of flame contact.

[0004] On the other hand, in the case of materials using phosphorus-based flame retardants, as typified by Patent Documents 1 and 2, although many studies have been conducted on the oxygen index and self-extinguishing properties such as UL94 V test, there have been few examples of in-depth studies on fire resistance and flame retardancy, and there has been a long awaited development of materials that clearly have the fire resistance and flame retardancy that society demands.

[0005] In recent years, a study has been reported in Patent Document 3, in which the fire resistance of a test piece in which a phosphorus-based flame retardant and glass fiber are combined is studied.

[0006] However, the technology disclosed in Patent Document 3 does not provide a sufficient flame exposure time for evaluation. For example, China's GB / T 38031-2020 standard assumes the occurrence of an electric vehicle fire and requires that "after a battery cell ignites in the battery pack, no smoke or fire should be emitted outside the battery pack for five minutes." However, the invention in Patent Document 3 does not take into consideration fire resistance performance of more than five minutes, and fails to discuss materials with the fire resistance and flame blocking properties that society actually requires. In other words, the problem of providing materials with the performance to withstand long-term flame exposure, which will be required in the future, remains unsolved.

[0007] Japanese Patent Application Laid-Open No. 2003-026935 Japanese Patent Application Laid-Open No. 2011-088970 International Publication No. 2020-071420 Pamphlet

[0008] In view of the above problems, the object of the present invention is to provide a material that combines a phosphorus-based flame retardant, glass fiber, and polypropylene, and that has both fire resistance and flame barrier properties that can withstand long-term flame contact and good fluidity that is excellent in moldability.

[0009] As a result of extensive research conducted to solve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by blending a flame retardant and a fiber in a specific ratio with a polypropylene resin and optimizing the melt flow rate (hereinafter sometimes abbreviated as MFR) of the resin portion relative to the amount of flame retardant, and the resulting polypropylene resin composition can solve the above-mentioned problems. Based on these findings, the present invention has been completed.

[0010] That is, the present invention has the following configuration. [1] A propylene-based resin composition containing a polypropylene-based resin (A) satisfying the following requirement (A1), a flame retardant (B) satisfying the following requirement (B1), and fibers (C) satisfying the following requirement (C1), and characterized by satisfying the following conditions 1 and 2. Requirement (A1) The polypropylene-based 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. Condition 1: The propylene-based resin composition contains 24 to 65% by weight of a polypropylene-based resin (A), 5 to 26% by weight of a flame retardant (B), and 30 to 50% by weight of fibers (C) (provided that the total of the polypropylene-based resin (A), the flame retardant (B), and the fibers (C) is 100% by weight). Condition 2: The melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene-based resin (A) and the content of the flame retardant (B) (provided that the total of the polypropylene-based resin (A), the flame retardant (B), and the fibers (C) is 100% by weight) satisfy either (Condition 2-1) or (Condition 2-2) below. (Condition 2-1) The content of the flame retardant (B) (unit: weight %, provided that the total of the polypropylene resin (A), the flame retardant (B), and the fiber (C) is taken as 100 weight %) is 5 weight % or more and less than 18 weight %, and the melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene resin (A) is 75 g / 10 min or less. (Condition 2-2) The content of the flame retardant (B) (unit: weight %, provided that the total of the polypropylene resin (A), the flame retardant (B), and the fiber (C) is taken as 100 weight %) is 18 weight % or more and 26 weight % or less, and the melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene resin (A) is 105 g / 10 min or less. [2] The propylene-based resin composition according to [1], wherein the polypropylene-based resin (A) further satisfies the following requirement (A2):Requirement (A2): The polypropylene-based resin (A) contains at least two types of polypropylene-based resins (Aa) and (Ab), and the melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene-based resin (Aa) is in the range of 60 to 2000 / 10 min. [3] The propylene-based resin composition according to [1] or [2], wherein the fiber (C) further satisfies the following requirement (C2): Requirement (C2): As the fiber (C), a glass fiber having a fiber length of 1 to 20 mm is used. [4] The propylene-based resin composition according to any one of [1] to [3], wherein the flame retardant (B) is a phosphorus-based flame retardant. [5] The propylene-based resin composition according to [4], wherein the flame retardant (B) is a polyphosphate. [6] A molded article obtained from the propylene-based resin composition according to any one of [1] to [5].

[0011] The present invention makes it possible to provide a material that can achieve both fire resistance and flame barrier properties that can withstand long-term flame contact, and good flowability that allows for excellent moldability. Modes for carrying out the invention

[0012] The present invention provides a propylene-based resin composition comprising a polypropylene-based resin (A) satisfying the following requirement (A1), a flame retardant (B) satisfying the following requirement (B1), and fibers (C) satisfying the following requirement (C1), and characterized by satisfying the following conditions 1 and 2. Requirement (A1): The polypropylene-based 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 fibers (C) are glass fibers. Requirement 1: The propylene-based resin composition contains 24 to 65% by weight of a polypropylene-based resin (A), 5 to 26% by weight of a flame retardant (B), and 30 to 50% by weight of fibers (C) (provided that the total of the polypropylene-based resin (A), the flame retardant (B), and the fibers (C) is 100% by weight). Condition 2 The melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene resin (A) and the content of the flame retardant (B) (where the total of the polypropylene resin (A), the flame retardant (B), and the fiber (C) is taken as 100% by weight) satisfy either (Condition 2-1) or (Condition 2-2) below. (Condition 2-1) The content of the flame retardant (B) (unit: weight %, where the total of the polypropylene resin (A), the flame retardant (B), and the fiber (C) is taken as 100% by weight) is 5% by weight or more and less than 18% by weight, and the melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene resin (A) is 75 g / 10 min or less. (Condition 2-2) The content of the flame retardant (B) (unit: weight %, where the total of the polypropylene-based resin (A), the flame retardant (B), and the fiber (C) is 100 weight %) is 18 weight % or more and 26 weight % or less, and the melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene-based resin (A) is 105 g / 10 min or less.

[0013] Each item of the propylene-based resin composition of the present invention will be described in detail 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-based resin composition contains 24 to 65% by weight of a polypropylene-based resin (A), 5 to 26% by weight of a flame retardant (B), and 30 to 50% by weight of fibers (C) (wherein the total of the polypropylene-based resin (A), the flame retardant (B), and the fibers (C) is 100% by weight). Details of the polypropylene-based resin (A), the flame retardant (B), and the fibers (C) will be described later.

[0016] The propylene-based resin composition must contain 24 to 65 wt% of polypropylene-based resin (A), preferably 29 to 59 wt%, more preferably 34 to 54 wt%, and even more preferably 40 to 49 wt%. The flame retardant (B) must be contained in an amount of 5 to 26 wt%, preferably 10 to 25 wt%, more preferably 14 to 24 wt%, and even more preferably 18 to 23 wt%. The fiber (C) must be contained in an amount of 30 to 50 wt%, preferably 31 to 46 wt%, more preferably 32 to 42 wt%, and even more preferably 33 to 38 wt%. By setting the contents of the polypropylene-based resin (A), flame retardant (B), and fiber (C) within these ranges, it is possible to provide a material that combines fire resistance and flame retardancy sufficient to withstand long-term flame contact with excellent flowability for moldability.

[0017] The propylene-based 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 polypropylene resin (A) and the content of the flame retardant (B) (where the total of the polypropylene resin (A), the flame retardant (B), and the fiber (C) is taken as 100% by weight) satisfy either (Condition 2-1) or (Condition 2-2) below. (Condition 2-1) The content of the flame retardant (B) (unit: weight %, where the total of the polypropylene resin (A), the flame retardant (B), and the fiber (C) is taken as 100% by weight) is 5% by weight or more and less than 18% by weight, and the melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene resin (A) is 75 g / 10 min or less. (Condition 2-2) The content of the flame retardant (B) (unit: weight %, where the total of the polypropylene-based resin (A), the flame retardant (B), and the fiber (C) is 100 weight %) is 18 weight % or more and 26 weight % or less, and the melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene-based resin (A) is 105 g / 10 min or less.

[0019] In general, a polypropylene resin (A) with a lower melt flow rate has better shape retention when the material is softened by heat such as flame contact, and tends to have good fire resistance and flame barrier properties even when the content of flame retardant (B) is low. On the other hand, even when the melt flow rate of polypropylene resin (A) is high, if the content of flame retardant (B) is high, in addition to the flame retardant effect of flame retardant (B), the melt flow rate of the mixture of polypropylene resin (A) and flame retardant (B) is reduced. Therefore, by increasing the content of flame retardant (B), it is possible to improve shape retention and achieve good fire resistance and flame barrier properties. In the present invention, in the region where the content of the flame retardant (B) is low, i.e., the region where the content of the flame retardant (B) (unit: weight %, where the total of the polypropylene resin (A), the flame retardant (B), and the fiber (C) is 100 weight %) defined in (Condition 2-1) is 5 weight % or more but less than 18 weight %, sufficient fire resistance and flame protection can be achieved by setting the melt flow rate of the polypropylene resin (A) to 75 g / 10 min or less. Here, if the melt flow rate of the polypropylene resin (A) exceeds 75 g / 10 min, sufficient shape retention cannot be obtained, and it may be difficult to achieve sufficient fire resistance and flame protection. Within this range, the melt flow rate is preferably 74 g / 10 min or less, more preferably 73 g / 10 min or less, even more preferably 72 g / 10 min or less, particularly preferably 71 g / 10 min or less, and especially preferably 70 g / 10 min or less. Furthermore, in the region where the content of the flame retardant (B) is high, i.e., the region where the content of the flame retardant (B) (unit: weight %, where the total of the polypropylene resin (A), the flame retardant (B), and the fiber (C) is 100 weight %) specified in (Condition 2-2) is 18 weight % or more and 26 weight % or less, good fire resistance and flame protection performance can be obtained even if the melt flow rate of the polypropylene resin (A) exceeds 75 g / 10 min, as long as it is 105 g / 10 min or less. However, even in the region where the content of the flame retardant (B) is high (Condition 2-2), if the melt flow rate of the polypropylene resin (A) exceeds 105 g / 10 min, sufficient fire resistance and flame protection may not be achieved.Within this range, the melt flow rate is preferably 104 g / 10 min or less, more preferably 103 g / 10 min or less, even more preferably 102 g / 10 min or less, particularly preferably 101 g / 10 min or less, and especially preferably 100 g / 10 min or less. In both (Condition 2-1) and (Condition 2-2), the lower limit of the melt flow rate of the polypropylene-based resin (A) is usually 0.5 g / 10 min, preferably 0.8 g / 10 min, even more preferably 1.0 g / 10 min, and even more preferably 1.5 g / 10 min. By setting the lower limit of the melt flow rate of the polypropylene-based resin (A) within this range, sufficient shape retention can be achieved, sufficient fire resistance and sufficient flame retardancy can be exhibited, and good moldability can be obtained. In other words, if the lower limit of the melt flow rate of the polypropylene-based resin (A) is lower than the above range, there is a high risk of deterioration in moldability.

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

[0021] Requirement (A1) The polypropylene-based resin (A) used in the present invention contains 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, the propylene-α-olefin block copolymer and the propylene-α-olefin random copolymer may be simply referred to as "propylene-α-olefin copolymer." The propylene-α-olefin copolymer preferably used is a copolymer containing propylene and an α-olefin having 2 to 8 carbon atoms other than propylene as comonomers, and has a propylene content of 70 to 99.99% by weight (i.e., a comonomer content of 0.01 to 30% by weight), and more preferably a random copolymer or block copolymer of propylene and an α-olefin having a propylene content of 90% by weight or more. Furthermore, a mixture of random copolymers or block copolymers containing 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 and is copolymerized with propylene, may be used alone or in combination of two or more. Specific examples of the propylene-α-olefin copolymer 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 ternary copolymers such as propylene-ethylene-butene-1 copolymer and propylene-ethylene-hexene-1 copolymer. Preferred are propylene-ethylene random copolymers and propylene-ethylene-butene-1 random copolymers. The content of the α-olefin monomer in the propylene-α-olefin copolymer is typically about 0.01 to 30% by weight, preferably about 1 to 20% by weight, and more preferably about 1 to 10% by weight.

[0023] Examples of the 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.

[0024] From the viewpoint of moldability, the polypropylene resin (A) preferably has a melting point of 100 to 170°C, more preferably 150 to 165°C. The melting point of the polypropylene resin can be appropriately controlled mainly by the types of propylene and α-olefins other than propylene used as raw materials, the copolymerization ratio, the melt flow rate (MFR), etc. The "melting point" referred to in this specification is the melting peak temperature measured by a differential scanning calorimeter (DSC).

[0025] The polypropylene resin (A) used in the present invention must satisfy either the above-mentioned (Condition 2-1) or (Condition 2-2) with respect to the melt flow rate (MFR) according to JIS K7210 [measurement temperature: 230°C, load: 2.16 kg (21.18 N)]. Therefore, the melt flow rate (MFR) is usually 0.5 to 105 g / 10 min, preferably 1.0 to 100 g / 10 min, more preferably 5.0 to 90 g / 10 min, and even more preferably 10 to 75 g / 10 min. By setting the melt flow rate (MFR) within this range, the propylene resin composition of the present invention and molded articles obtained by molding it can maintain good flame retardancy, i.e., fire resistance, flame blocking, and moldability, while also exhibiting good scratch resistance and flexural strength.

[0033] That is, if the melt flow rate (MFR) is less than 0.5 g / 10 min, the load when molding the propylene-based resin composition of the present invention increases, resulting in poor moldability and the risk of discoloration of the molded article and a poor appearance, while if it exceeds 105 g / 10 min, scratch resistance and flexural strength may be impaired and sufficient shape retention may not be obtained, resulting in the risk of not being able to obtain sufficient fire resistance and sufficient flame protection. When the polypropylene-based resin (A) contains two or more propylene polymers, all of these two or more propylene polymers may have a melt flow rate (MFR) within the above-mentioned range, or some or all of the two or more propylene polymers may have a melt flow rate (MFR) outside the above-mentioned range, but the polypropylene-based resin (A) as a whole may have a melt flow rate (MFR) within the above-mentioned range.

[0026] Furthermore, the polypropylene resin (A) preferably used in the present invention has an isotactic pentad fraction (mmmm fraction), which indicates the degree of crystallinity, of 96% or more, more preferably an isotactic pentad fraction of 97% or more. When the isotactic pentad fraction is 96% or more, scratch resistance and bending strength are improved, which is preferable. This is due to the effect of the crystal orientation in the surface layer of the molded product in the polypropylene resin (A). The crystallinity of the polypropylene resin (A) can be adjusted by controlling the copolymerization ratio of the raw materials and the molecular weight distribution by the catalyst used. The isotactic pentad fraction (mmmm) is １３ It is a value measured using C-NMR (nuclear magnetic resonance) and is a nuclear magnetic resonance spectrum ( １３ The isotactic pentad fraction is the isotactic fraction of pentad units in a polypropylene molecular chain measured using C-NMR. That is, the isotactic pentad fraction is the fraction of propylene units in which five consecutive propylene monomer units are isotactically bonded. Specifically, １３ The isotactic pentad unit is measured by the intensity fraction of the mmmm peak among all absorption peaks in the methyl carbon region of the C-NMR spectrum, and for example, a 270 MHz FT-NMR device manufactured by JEOL Ltd. is used.

[0027] 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 is a combination of a titanium compound and an organoaluminum compound (for example, as described in Polypropylene Handbook (first edition, first printing published May 15, 1998)), or a metallocene catalyst (for example, as described in JP-A-5-295022) can be used.

[0028] The polymerization process used to obtain the polypropylene-based 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. Furthermore, either batch polymerization or continuous polymerization can be used, and if desired, multi-stage continuous polymerization, such as two-stage or three-stage, can also be used. It can also be produced by mechanically melt-kneading two or more propylene polymers. Various polypropylene resins that can be used as the polypropylene-based resin (A) are commercially available from many companies, and examples thereof include the Novatec series manufactured by Japan Polypropylene Corporation. It is also possible to purchase and use a product having the desired physical properties from these commercially available products.

[0029] The polypropylene resin (A) used in the present invention preferably further satisfies the following requirement (A2). Requirement (A2): The polypropylene resin (A) contains at least two polypropylene resins (Aa) and (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 / 10 min. One embodiment of the present invention involves producing a masterbatch by kneading the flame retardant (B) and the fibers (C) with different polypropylene resins (carrier resins), and then, if necessary, kneading the masterbatch with another polypropylene resin in a molding machine. In this case, for the fiber masterbatch, a resin with a high melt flow rate (MFR) must be used as the carrier resin, because a low melt flow rate (MFR) of the carrier resin results in poor dispersion of the fibers (C). On the other hand, in the present invention, if the melt flow rate (MFR) of the polypropylene resin (A) is too high, the fire resistance and flame retardancy will be reduced, so it is necessary to adjust the melt flow rate (MFR) of the entire polypropylene resin (A) using a polypropylene resin with a low melt flow rate (MFR). Therefore, in an embodiment using a masterbatch in which fiber (C) is kneaded with a polypropylene resin (carrier resin), at least two polypropylene resins are required. In this case, it is preferable to use the other polypropylene resin as a carrier resin in the masterbatch of the flame retardant (B) because this simplifies the kneading process. The melt flow rates (MFR) of the two or more polypropylene resins (Aa) may be the same or different, but it is preferable that the melt flow rate (MFR) of (Aa) is higher than the melt flow rate (MFR) of (Ab), as this makes it easier to adjust the melt flow rate (MFR) of the polypropylene resin (A) to a desired range.

[0030] Here, the melt flow rate (MFR) of the polypropylene-based resin (Aa) is preferably 60 to 2000 g / 10 min, more preferably 70 to 1000 g / 10 min, more preferably 80 to 900 g / 10 min, particularly preferably 100 to 800 g / 10 min, and most preferably 100 to 700 g / 10 min. The melt flow rate (MFR) of the polypropylene-based resin (A) as a whole, comprising at least two polypropylene-based resins (Aa) and (Ab), is the same as the melt flow rate (MFR) of the polypropylene-based resin (A) described above. In this specification, the melt flow rate (MFR) is a value measured in accordance with JIS K7210 at a test temperature of 230°C and a load of 2.16 kg. When a plurality of polypropylene resins are mixed and used as the polypropylene resin (A), it is preferable to use the melt flow rate (MFR) value obtained by calculation using the logarithmic additivity rule (see, for example, the following formula (1)) described in Japanese Patent No. 6331720. Ａ ) represents the melt flow rate of the resin portion obtained by calculation, hereinafter referred to as MFR Ａ It is sometimes abbreviated as log(MFR Ａ ) = {(% by weight of component (PP-A) × log (MFR of component (PP-A)) + (% by weight of component (PP-B) × log (MFR of component (PP-B)) + (% by weight of component (PP-C) × log (MFR of component (PP-C))} / 100 ... Formula (1)

[0031] The types of polypropylene-based resin (Aa) and polypropylene-based resin (Ab) (i.e., types of propylene polymers), preferred melting points, and preferred isotactic pentad fractions are as described in detail for polypropylene-based resin (A). Two or more types of polypropylene-based resin (Ab) may be contained.

[0032] The ratio of the total content of the polypropylene resins (Aa) to the total content of the polypropylene resins (Ab) in the polypropylene resin (A) can be set arbitrarily, taking into consideration the melt flow rate (MFR) of the entire polypropylene resin (A). That is, as described above, in the present invention, it is important to set the melt flow rate (MFR) of the polypropylene resin (A) within a desired range and, within that desired range, to adjust the content of the flame retardant (B) within a specific range.

[0033] (2) Flame Retardant (B) The flame retardant (B) used in the present invention will be described in detail below.

[0034] Requirement (B1) The flame retardant (B) used in the present invention is an organic flame retardant. Generally, a larger amount of inorganic flame retardant is required to achieve the required flame retardancy, and the specific gravity increases when attempting to achieve high flame retardancy. In contrast, organic flame retardants can achieve flame retardancy with a relatively low addition amount, making it possible to achieve high 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).

[0035] 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 such as guanidine-based can be used, but phosphorus-based flame retardants are preferred.

[0036] Any phosphorus-based flame retardant generally used as a flame retardant for polyolefins can be used. Examples include compounds modified with various substituents such as trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, tricyclohexyl phosphate, trixylyl phosphate, cresyl diphenyl phosphate, dicresyl phenyl phosphate, dimethyl ethyl phosphate, trixylyl phosphate, methyl dibutyl phosphate, ethyl dipropyl phosphate, and hydroxyphenyl diphenyl phosphate; phosphate compounds; and compounds or mixtures of phosphazene derivatives containing phosphorus and nitrogen. These phosphorus-based flame retardants may be used alone or in combination of two or more.

[0037] 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 intumescent layer during combustion, which is suitable for improving fire resistance and flame resistance. Examples of polyphosphates include the phosphates described in [Patent Document 1] JP 2003-026935 A, paragraphs

[0015] to

[0021] .

[0038] In addition to the phosphorus-based flame retardant, other organic flame retardants that do not fall under the category of phosphorus-based flame retardants, such as halogen-based and nitrogen compounds, can also be used.

[0039] Preferred examples of halogenated flame retardants include organic halogenated aromatic compounds such as halogenated diphenyl compounds, halogenated bisphenol compounds, halogenated bisphenol-bis(alkyl ether) compounds, and halogenated phthalimide compounds, with halogenated bisphenol-bis(alkyl ether) compounds being more preferred. Examples of the halogenated diphenyl compounds include halogenated diphenyl ether compounds, halogenated diphenyl ketone compounds, and halogenated diphenylalkane compounds, with decabromodiphenylethane and other halogenated diphenylalkane compounds being preferred.

[0040] Examples of the halogenated bisphenol-based compound include halogenated bisphenylalkanes, halogenated bisphenyl ethers, halogenated bisphenyl thioethers, and halogenated bisphenyl sulfones. Among these, halogenated bisphenyl thioethers such as bis(3,5-dibromo-4-hydroxyphenyl)sulfone are preferred.

[0041] Examples of the 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, 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) 1,2-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) bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl)-(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 ether, (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, 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.

[0042] 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. Examples of etherified tetrabromobisphenol S include 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 are less likely to decompose even when subjected to heat history during production and molding of the polypropylene-based resin composition of the present invention.

[0043] Examples of the nitrogen compounds 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, acrylguanamine, 2,4-diamino-6-nonyl-1,3,5-trimethyl- ... 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 suitable compounds include those in which melamine cyanurate, melamine pyrophosphate, butylenediguanamine, norbornenediguanamine, methylenediguanamine, ethylenedimelamine, trimethylenedimelamine, tetramethylenedimelamine, hexamethylenedimelamine, 1,3-hexylenedimelamine, etc. are substituted. Commercially available products include Adeka STAB FP2000, FP2100, FP2200, and FP2500S manufactured by ADEKA CORPORATION, and ammonium polyphosphate.

[0044] When a phosphorus-based flame retardant is used in combination with any of the above organic flame retardants such as halogen-based and nitrogen-based compounds, the organic flame retardants may be used alone or in combination of two or more. For example, a phosphorus-based flame retardant may be used in combination with an organic halogen-based flame retardant and a nitrogen-based compound.

[0045] (3) Fiber (C) The fiber (C) used in the present invention will be described in detail below.

[0046] Requirement (C1) The fiber (C) is a glass fiber. The fiber (C) not only improves the physical properties such as rigidity and impact strength of the propylene-based resin composition of the present invention and the molded article obtained therefrom, but also contributes to the improvement of additional physical properties such as heat resistance, dimensional stability (e.g., reduced linear expansion coefficient), low shrinkage, and scratch resistance.

[0047] (3-1) Types and Production Methods of Glass Fibers As described above, fiber (C) is a glass fiber. Using glass fiber as fiber (C) is preferred in terms of ease of production and economy of the propylene-based resin composition of the present invention and the molded article obtained therefrom. To further enhance the effects of the present invention, two or more types of fiber (C) can be used in combination, or they can be used in the form of a so-called masterbatch in which they are previously incorporated into the polypropylene-based resin (A) or the like at a relatively high concentration. Furthermore, other materials not falling under the category of fiber (C), such as glass beads, glass balloons, mica, and various inorganic or organic fillers not falling 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.

[0048] The glass fiber can be used without any particular limitation, and examples of the type of glass used for the fiber include E-glass, C-glass, A-glass, and S-glass, among which E-glass is preferred. The method for producing the glass fiber is not particularly limited, and the glass fiber can be produced by various known production methods.

[0049] The fiber diameter of the glass fiber is preferably 3 μm to 25 μm, more preferably 6 μm to 20 μm. By setting the fiber diameter of the glass fiber within this range, the glass fiber is less likely to break during the production and molding of the propylene-based resin composition of the present invention and the molded article obtained therefrom, and the fiber aspect ratio can be set within a favorable range, thereby making it possible to effectively improve the rigidity and impact strength of the propylene-based resin composition of the present invention and the molded article obtained therefrom. That is, if the fiber diameter is less than 3 μm, the glass fiber may be more likely to break during the production and molding of the propylene-based resin composition of the present invention and the molded article obtained therefrom. On the other hand, if the fiber diameter exceeds 25 μm, the fiber aspect ratio decreases, and the effect of improving the rigidity and impact strength of the propylene-based resin composition of the present invention and the molded article obtained therefrom may be reduced.

[0050] Furthermore, it is preferable that the glass fiber serving as fiber (C) further satisfies the following requirement (C2). Requirement (C2) Glass fibers having a fiber length of 1 to 20 mm are used as fiber (C). This fiber length is determined from values ​​measured using a microscope, calipers, or the like. Furthermore, when glass fiber-containing pellets are obtained using a method such as the so-called pultrusion method, the glass fiber length in the pellets is substantially the same as the length of one side of the pellets (in the extrusion direction), resulting in "glass fiber-containing pellets." Therefore, the length of the pellets may be used as the glass fiber length. Furthermore, the fiber diameter is determined from values ​​measured using a microscope, calipers, or the like.

[0051] The glass fiber can also be used as so-called chopped strand glass fiber, which is obtained by cutting a fiber yarn to a desired length. When so-called chopped strand glass fiber is used as the glass fiber, a shorter glass fiber length facilitates handling and kneading, and is therefore preferably 2 mm to 15 mm, more preferably 3 mm to 10 mm, and even more preferably 4 mm to 8 mm. By setting the length of the glass fiber within this range, it is possible to improve both the physical properties such as rigidity and impact strength of the propylene-based resin composition of the present invention and the molded article obtained therefrom, as well as the moldability (fluidity). That is, if the fiber (C) is a glass fiber and its fiber length is less than 1 mm, the physical properties such as rigidity and impact strength of the propylene-based resin composition of the present invention and the molded article obtained therefrom may be reduced, while if it exceeds 20 mm, the moldability (fluidity) may be reduced. In this case, the fiber length can also be expressed as the length when the glass fiber is used as a raw material as is. However, this does not apply to the case of glass fiber-containing pellets, which are made by aggregating and integrating a large number of continuous glass fibers through melt extrusion, as will be described later, and roving-like ones are usually used. Two or more types of glass fibers can also be used in combination.

[0052] Both surface-treated and untreated glass fibers can be used. However, to improve dispersibility in the polypropylene resin (A), it is preferable to use glass fibers that have been surface-treated with an organic silane coupling agent, titanate coupling agent, aluminate coupling agent, zirconate coupling agent, silicone compound, higher fatty acid, fatty acid metal salt, fatty acid ester, or the like. 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 isopropyl triisostearoyl titanate, isopropyl tris(dioctylpyrophosphate)titanate, and isopropyl tri(N-aminoethyl)titanate. Examples of aluminate coupling agents include acetoalkoxyaluminum diisopropylate. Examples of the zirconate coupling agent include tetra(2,2-diallyloxymethyl)butyl, di(tridecyl)phosphitozirconate, neopentyl(diallyl)oxy, and trineodecanoyl zirconate. Examples of the silicone compound include silicone oil and silicone resin.

[0053] Furthermore, examples of higher fatty acids used in surface treatment include oleic acid, capric acid, lauric acid, palmitic acid, stearic acid, montanic acid, caraic acid, linoleic acid, rosin acid, linolenic acid, undecanoic acid, and undecenoic acid. Furthermore, examples of higher fatty acid metal salts include sodium salts, lithium salts, calcium salts, magnesium salts, zinc salts, and aluminum salts of fatty acids having 9 or more carbon atoms, such as stearic acid and montanic acid. Among these, calcium stearate, aluminum stearate, calcium montanate, and sodium montanate are preferred. Furthermore, 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 the glass fiber.

[0054] The glass fibers may be subjected to a bundling (surface) treatment with a sizing agent, and examples of the sizing agent include epoxy-based sizing agents, aromatic urethane-based sizing agents, aliphatic urethane-based sizing agents, acrylic-based sizing agents, and maleic anhydride-modified polyolefin-based sizing agents. These sizing agents must be melted during melt-kneading with the polypropylene-based resin (A), and therefore are preferably those that melt at 200° C. or less.

[0055] A specific example of the so-called chopped strand glass fiber is T480H manufactured by Nippon Electric Glass Co., Ltd.

[0056] These glass fibers may also be used as "glass fiber-containing pellets" prepared by melt-extruding a desired amount of, for example, polypropylene resin (A) using a method such as the so-called pultrusion method to form pellets in which a large number of continuous glass fibers are aggregated and integrated, and the length of the glass fibers in the pellets is substantially the same as the length of one side (in the extrusion direction) of the pellets, which is preferred from the viewpoint of further improving the physical properties, such as rigidity and impact strength, of the propylene resin composition of the present invention and the molded article obtained by molding it. In this case, "substantially" specifically means that the length of 50% or more, preferably 90% or more of the glass fibers in the glass fiber-containing pellets is the same as the length (in the extrusion direction) of the glass fiber-containing pellets, based on the total number of the glass fibers, and that the fibers are hardly broken during the preparation of the pellets.

[0057] The method for producing such glass fiber-containing pellets is not particularly limited, but for example, a method (pultrusion method, pultrusion method) in which a resin extruder is used to pull a large number of continuous glass fibers from a fiber rack through a crosshead die, and an arbitrary amount of polypropylene resin is melt-extruded (impregnated) in a molten state to aggregate and integrate the large number of glass fibers is preferred because it hardly causes fiber breakage.

[0058] The length (in the extrusion direction) of the glass fiber-containing pellets varies depending on the glass fiber used, but as mentioned above, it is 1 mm to 20 mm. When glass fiber-containing pellets are used as the glass fiber, a longer glass fiber length (length of the glass fiber-containing pellets) facilitates pellet production and handling, so a length of 3 mm to 18 mm is more preferable, 4 mm to 15 mm is even more preferable, and 5 mm to 12 mm is particularly preferable. By setting the length of the glass fiber, i.e., the length of the glass fiber-containing pellets, within this range, it is possible to improve both the physical properties, such as rigidity and impact strength, and moldability (fluidity), of the propylene-based resin composition of the present invention and the molded article obtained therefrom. That is, if the length is less than 1 mm, the physical properties, such as rigidity and impact strength, of the propylene-based resin composition of the present invention and the molded article obtained therefrom may be reduced, while if it exceeds 20 mm, the moldability (fluidity) may be reduced. The fiber diameter of the glass fiber is usually 3 to 25 μm, preferably 5 to 23 μm, more preferably 7 to 21 μm, and even more preferably 9 to 19 μm. By setting the fiber diameter of the glass fiber within this range, dispersion in the polypropylene resin is improved, thereby enabling the resulting polypropylene resin composition to exhibit good flame retardancy while maintaining good fluidity and mechanical properties. Furthermore, 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 pellets. When glass fiber-containing pellets having a glass fiber content within this range are used in the present invention, the propylene resin composition of the present invention and the molded article obtained therefrom can have good physical properties such as rigidity and impact strength, as well as moldability (fluidity). That is, when glass fiber-containing pellets having a glass fiber content of less than 20% by weight are used in the present invention, the propylene resin composition of the present invention and the molded article obtained therefrom may have poor physical properties such as rigidity and impact strength. On the other hand, when glass fiber-containing pellets having a glass fiber content of 70% by weight or more are used, moldability (fluidity) may be poor.

[0059] (4) Additive (D) In ​​addition to the polypropylene resin (A), flame retardant (B), and fiber (C), the propylene resin composition of the present invention may contain, as needed, an optional additive (D) typically used in polypropylene resins, within a range that does not impair the object of the present invention. Examples of the additive (D) include a nucleating agent, a molecular weight regulator, a foaming agent, a pigment, an ultraviolet absorber, an antioxidant, an antistatic agent, a neutralizing agent, a metal deactivator, a stabilizer, an antibacterial agent, an inorganic filler, and a rubber-like component.

[0060] As the molecular weight lowering agent, for example, various organic peroxides and so-called 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-butylperoxyisopropyl carbonate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexyne-3, t-butyl-diperadipate, t-butylperoxy-3,5,5-trimethylhexanoate, methylethylketone peroxide, cyclohexanone peroxide, di-t-butyl peroxide, dicumyl 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-butylcumyl peroxide, 1,1-bis- Examples include, but are not limited to, one or more compounds 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-tetra-methylbutyl hydroperoxide, and 2,5-di-methyl-2,5-di-(hydroperoxy)hexane.

[0061] The type of blowing agent that can be used in the present invention is not particularly limited, and known blowing agents used in plastics, rubber, etc. can be used. Also, any blowing agent used in various foam molding processes can be used, including physical blowing agents, decomposable blowing agents (chemical blowing agents), and microcapsules containing thermal expansion agents. 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, dichloromethane, chloroethane, dichlorotrifluoroethane, dichlorofluoroethane, chlorodifluoroethane, dichloropentafluoroethane, tetrafluoroethane, difluoroethane, pentafluoroethane, trifluoroethane, trichlorotrifluoroethane, dichlorotetrafluoroethane, chloropentafluoroethane, and perfluorocyclobutane; and inorganic gases such as water, carbon dioxide, and nitrogen. These compounds may be used alone or in combination. Among them, aliphatic hydrocarbons such as propane, butane, and pentane, and carbon dioxide gas are preferred because they are inexpensive and have high solubility in polypropylene-based resins. In particular, when carbon dioxide gas is used, it is more preferred to use it under supercritical conditions of 7.4 MPa or more and 31°C or more, since this results in a state in which it is highly diffusible and soluble in the propylene-based resin composition.

[0062] When a physical foaming agent is used, a foam regulator can be used as necessary. Examples of foam regulators include inorganic decomposable foaming agents such as ammonium carbonate, sodium bicarbonate (sodium bicarbonate), ammonium bicarbonate, and ammonium nitrite; azo compounds such as azodicarbonamide, azobisisobutyronitrile, and diazoaminobenzene; nitroso compounds such as N,N'-dinitrosopentanemethylenetetramine and N,N'-dimethyl-N,N'-dinitrosoterephthalamide; organic decomposable foaming agents such as benzenesulfonyl hydrazide, p-toluenesulfonyl hydrazide, p,p'-oxybisbenzenesulfonylsemicarbazide, p-toluenesulfonylsemicarbazide, trihydrazinotriazine, and barium azodicarboxylate; inorganic powders (inorganic powders) such as talc and silica; acid salts of 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 a cell regulator is used, the blending amount of the cell regulator is preferably in the range of 0.01 to 5 parts by weight in pure content per 100 parts by weight of the propylene-based resin composition. Specific examples of decomposable foaming agents (chemical foaming agents) include a mixture of organic acids such as sodium bicarbonate and 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'-dinitrosoterephthalamide, sulfohydrazide-based foaming agents such as p,p'-oxybisbenzenesulfonylhydrazide and p-toluenesulfonylsemicarbazide, and trihydrazinotriazine. The amount of the foaming agent to be 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, based on 100 parts by weight of the propylene-based resin composition.

[0063] The pigment may be any of known organic or inorganic pigments, including organic pigments such as azo, anthraquinone, phthalocyanine, quinacridone, isoindolinone, diosadin, perinone, quinophthalone, and perylene pigments, and inorganic pigments such as ultramarine, titanium oxide, titanium yellow, iron oxide (red oxide), chromium oxide, zinc white, and carbon black.

[0064] Examples of light stabilizers and ultraviolet absorbers that are effective in imparting and improving the weather resistance and durability of the propylene-based resin composition of the present invention and the molded articles produced by molding the same include hindered amine compounds such as condensates 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 the benzotriazole-based solvents include 2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole and 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole. Examples of the benzophenone-based solvents include 2-hydroxy-4-methoxybenzophenone and 2-hydroxy-4-n-octoxybenzophenone. Examples of the salicylate-based solvents include 4-t-butylphenyl salicylate and 2,4-di-t-butylphenyl 3',5'-di-t-butyl-4'-hydroxybenzoate. Here, the method of using the light stabilizer and the ultraviolet absorber in combination is preferable because it has a significant effect of improving weather resistance, durability, etc. Two or more of these may be used in combination.

[0065] As the antioxidant, for example, phenol-based, phosphorus-based, or sulfur-based antioxidants are effective in imparting or improving the heat resistance, processing stability, heat aging resistance, etc. of the polypropylene resin composition of the present invention and the molded articles obtained by molding it.

[0066] As the antistatic agent, for example, a nonionic or ionic antistatic agent is effective in imparting or improving the antistatic properties of the propylene-based resin composition of the present invention and the molded article obtained by molding it.

[0067] In particular, as the antistatic agent, ionic agents such as cationic, anionic, nonionic, and amphoteric agents, fatty acid partial esters such as glycerin fatty acid monoesters, etc. can be used. Specific examples include alkyltrimethylammonium salts, dialkyldimethylammonium salts, benzalkonium salts, N,N-bis(2-hydroxyethyl)-N-(3-dodecyloxy-2-hydroxypropyl)methylammonium methosulfate, (3-laurylamidopropyl)trimethylammonium methylsulfate, stearamidopropyldimethyl-2-hydroxyethylammonium nitrate, stearamidopropyldimethyl-2-hydroxyethylammonium phosphate, cationic polymers, alkyl sulfonates, alkylbenzene sulfonates, sodium alkyldiphenylether disulfonate, alkyl nitrate ester salts, phosphorus Examples of suitable hydroxypropyl esters include alkyl ester salts, alkyl phosphate amine salts, stearic acid monoglyceride, pentaerythritol fatty acid esters, sorbitan monopalmitate, sorbitan monostearate, diglycerin fatty acid esters, alkyldiethanolamines, alkyldiethanolamine fatty acid monoesters, alkyldiethanolamides, polyoxyethylene dodecyl ethers, polyoxyethylene alkylphenyl ethers, polyethylene glycol monolaurates, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyether block copolymers, cetyl betaine, and hydroxyethyl imidazoline sulfate. These may be used in combination of two or more.

[0068] Examples of nucleating agents that can be used include aromatic aluminum salt-based nucleating agents, aromatic sodium salt-based nucleating agents, phosphorus-based nucleating agents such as aromatic metal phosphates, sorbitol nucleating agents, rosin 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 nucleating agents 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 p-t-butylbenzoate, sodium montanate, calcium montanate, aluminum oxide, kaolin clay, talc, rosins, petroleum resins, etc. These may be used in combination of two or more.

[0069] Examples of usable metal deactivators include triazines, phosphones, epoxies, triazoles, hydrazides, and oxamides. Specific examples include N,N'-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl]hydrazine, isophthalic acid bis(2-phenoxypropionylhydrazide), decanedicarboxylic acid disalicyloyl hydrazide, oxalic acid bisbenzylidenehydrazide, N,N'-bis{2-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxyl]ethyl}oxamide, 3-(N-salicyloyl)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. These may be used in combination of two or more.

[0070] As the neutralizing agent, various fatty acid metal salts can be used. Specific examples include saturated or unsaturated fatty acids with a molecular weight of about 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), and salts of metals such as lithium, sodium, calcium, magnesium, aluminum, and zinc. Two or more of these may be used in combination.

[0071] The antibacterial agent may be either an organic or inorganic antibacterial agent. Examples of organic antibacterial agents include chlorine-based, phenol-based, imidazole-based, or thiazole-based compounds, and 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.

[0072] Furthermore, specific examples of inorganic fillers include talc, barium sulfate, clay, silica, calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, glass fiber, whiskers, and the like.

[0073] As the rubber component, so-called elastomers or plastomers can be used, specifically ethylene-propylene rubbers, ethylene-butene-1 rubbers, ethylene-hexene rubbers, ethylene-octene rubbers, and styrene-butadiene rubbers, etc., and various commercially available products may be used within the range that does not impair the effects of the present invention.

[0074] 2. Method for Preparing Propylene-Based Resin Composition Examples of methods for preparing the propylene-based resin composition of the present invention include a method in which a predetermined amount of flame retardant (B), fiber (C), and optional additive (D) are added directly to powder or pellets of polypropylene-based resin (A); a method in which a masterbatch containing powder of polypropylene-based resin (A), flame retardant (B), fiber (C), and optional additive (D) is prepared in advance and the masterbatch is added to pellets of polypropylene-based resin; a method in which flame retardant (B) and optional additive (D) are added to powder or pellets of polypropylene-based resin (A) to first prepare a masterbatch of flame retardant (B), and further fiber (C) and optional additive (D) are added to powder or pellets of polypropylene-based resin (A) to prepare a masterbatch of fiber (C), and then the obtained masterbatch of flame retardant (B) and the masterbatch of fiber (C) are melt-kneaded together.

[0075] 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 a tumbler mixer, super mixer, Henschel mixer, screw blender, ribbon blender, etc. can be used for mixing. The melt kneading is not particularly limited as long as it is performed at a temperature equal to or higher than the melting point of the polypropylene resin (A) using, for example, a melt extruder, a Banbury mixer, etc.

[0076] The propylene-based resin composition of the present invention has an overall melt flow rate (MFR, 230°C, 2.16 kg load) of usually 1 to 60 g / 10 min, preferably 2 to 50 g / 10 min, more preferably 5 to 40 g / 10 min, and particularly preferably 10 to 30 g / 10 min. By controlling the overall MFR within this range, good moldability can be maintained while at the same time good flame retardancy can be obtained.

[0077] 3. Molding and Uses of Propylene-Based Resin Composition (1) Molding Another aspect of the present invention is a molded article obtained from the propylene-based resin composition of the present invention. The propylene-based 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 achieve the effects of the present invention, and it is preferable to obtain a molded article by such a molding method. The propylene-based resin composition of the present invention can also be molded by various molding methods such as blow molding, extrusion molding, compression (press) molding, foam (expansion) molding, sheet molding, thermoforming, stamping molding, and powder molding, as necessary, to obtain a desired molded article (e.g., an extrusion molded article). Among these, molding methods other than foam (expansion) molding are preferred.

[0078] (2) Applications Examples of applications of injection-molded articles obtained from the propylene-based resin composition of the present invention include home appliance parts such as rice cookers, vacuum cleaners, washing machines, refrigerators, electric fans, and air conditioners; home appliance parts such as vanities, ventilation fans, toilet seats, toilet covers, and housings for devices used as accessories; general batteries and battery peripheral parts; and battery peripheral parts for electric vehicles.

[0079] 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.

[0080] 1. Evaluation Method 1) MFR of Resin Portion The melt flow rate (MFR) of the resin portion was measured in accordance with JIS K7210 at a test temperature of 230°C and a load of 2.16 kg. In the present example, when a mixture of multiple polypropylene resins was used as the polypropylene resin (A), the melt flow rate (MFR) of the resin portion used was Ａ ) was calculated according to the logarithmic additivity rule using the following formula (1): log(MFR Ａ) = {(% by weight of component (PP-A) × log (MFR of component (PP-A)) + (% by weight of component (PP-B) × log (MFR of component (PP-B)) + (% by weight of component (PP-C) × log (MFR of component (PP-C))} / 100 ... Formula (1)

[0081] 2) Flame Retardancy Test (Fire Resistance Evaluation) 2)-1. Flame Retardancy Time Evaluation Using an injection molding machine [Toshiba EC180, long fiber screw mounted], 170 × 170 mm test pieces (thickness: 3.0 mmt) were molded under the following conditions: cylinder temperature: 200 ° C, mold temperature: 40 ° C, injection pressure: 60 MPa, injection speed: 60 mm / sec, and a flame retardancy test was performed. The details of the flame retardancy test are as follows. A 125 mm flame used in UL94 5VA was applied to the test piece from below the flat surface. At this time, the distance between the test piece and the burner port was 100 mm. In this state, the flame was applied for 15 minutes, and the time until the flame penetrated was measured and recorded as the flame retardancy time of the flame retardancy test. If the flame did not penetrate after 15 minutes of continued flame application, the flame application was discontinued. The evaluation of the flame retardancy time is as follows. ◎: The flame did not penetrate within 15 minutes of flame contact (denoted as >900) ◯: The flame penetrated within 10 minutes or more but less than 15 minutes △: The flame penetrated within 5 minutes or more but less than 10 minutes ×: The flame penetrated in less than 5 minutes

[0082] 2)-2. Evaluation of Shape Retention For samples that were not penetrated by flames for 15 minutes in the above flame-proofing test, the shape retention of the samples was evaluated 15 minutes after the flame was applied in the above flame-proofing test. The evaluation of shape retention is as follows: ◎: No cracks or fissures were observed on the flame-applied surface. ○: Cracks of less than 1 cm in size were observed in the vertical direction (below the flame-applied surface) of the flame-applied surface. △: Cracks of 1 cm or more but less than 8 cm in size were observed in the vertical direction (below the flame-applied surface) of the flame-applied surface. ×: Cracks of 8 cm or more in size were observed in the vertical direction (below the flame-applied surface) of the flame-applied surface. -: The flame penetrated in less than 15 minutes in the flame-proofing test, so the sample was not included in the evaluation of shape retention.

[0083] 2)-3. Overall evaluation of flame resistance Based on the above evaluation of flame resistance time and shape retention, an overall evaluation was made as follows: ◎: When both evaluations were evaluated as ◎ ○: When the flame resistance time was evaluated as ◎ and the shape retention was evaluated as 〇 or △ △: When the flame resistance time was evaluated as 〇 ×: When the flame resistance time was evaluated as △ or ×, or when the shape retention was evaluated as ×

[0084] 3) Evaluation of fluidity (spiral flow) Using an injection molding machine [Toshiba EC180, long fiber screw installed], injection molding was performed using a 20 mm wide x 2.5 mm thick spiral flow mold under the following conditions: cylinder temperature: 200°C, mold temperature: 40°C, injection pressure: 60 MPa, injection speed: 50 mm / sec. Spiral flow test pieces of 20 mm wide x 2.5 mm thick were produced. The length of the molded test pieces was measured, and the longer the length, the higher the fluidity. The fluidity was evaluated as follows: ◎: 420 mm or more; ◯: 370 mm or more but less than 420 mm; △: 320 mm or more but less than 370 mm; ×: Less than 320 mm.

[0085] 4) Mechanical properties (bending strength) Measurements were made at 23°C in accordance with JIS K7203. The dimensions of the molded product were 90 x 10 x 4 mm, and the unit was MPa. The mechanical properties were evaluated as follows: ◎: Bending strength was 190 MPa or more; ○: Bending strength was 180 MPa or more but less than 190 MPa; △: Bending strength was 170 MPa or more but less than 180 MPa; ×: Bending strength was less than 170 MPa

[0086] 5) Overall Evaluation Based on the overall evaluation of flame retardancy, the evaluation of fluidity, and the evaluation of mechanical properties, an overall evaluation was made as follows: ◎: No × or △ in any evaluation, and only ○ and ◎ evaluations ○: No × in any evaluation, and all evaluations are △ or higher, with at least one evaluation being ○ or higher △: All evaluations are △ ×: At least one evaluation of any of the evaluations is × In the comparative examples, if any of the above evaluations was rated "×", the overall evaluation was also determined to be "×", so in some cases no other evaluations were made.

[0087] 2. Materials Polypropylene Resin (A) (A-1) Novatec PP Series, MA1B (propylene homopolymer, MFR: 20 g / 10 min), manufactured by Japan Polypropylene Corporation (A-2) Novatec PP Series, SA08A (propylene homopolymer, MFR: 75 g / 10 min), manufactured by Japan Polypropylene Corporation (A-3) Novatec PP Series, MA3 (propylene homopolymer, MFR: 11 g / 10 min), manufactured by Japan Polypropylene Corporation (A-4) Novatec PP Series, MA04C (propylene homopolymer, MFR: 40 g / 10 min), manufactured by Japan Polypropylene Corporation (A-5) Novatec PP Series, FY6H (propylene homopolymer, MFR: 2 g / 10 min), manufactured by Japan Polypropylene Corporation (A-6) The above (A-3) was mixed with an organic peroxide to adjust the MFR of (A-3), and this was used as (A-6) (propylene homopolymer, MFR: 150 g / 10 min). (A-7) The above (A-3) was mixed with an organic peroxide to adjust the MFR of (A-3), and this was used as (A-7) (propylene homopolymer, MFR: 650 g / 10 min). Organic flame retardant (B) (B-1) FP2500S (phosphorus-based flame retardant containing polyphosphate) manufactured by ADEKA Corporation Fiber (C) (C-1) Glass fiber: RS2300, 2300TEX manufactured by Nitto Boseki Co., Ltd., fiber diameter 17 μm Other additives (D) As other additives (D), antioxidants (D-1: Irganox 1010 manufactured by BASF), (D-2: Irgafos 168 manufactured by ADEKA Corporation), and maleic anhydride-modified polypropylene (D-3: OREVAC CA100 manufactured by Arkema) were used.

[0088] 3. Preparation of various masterbatches (MB) 1) Flame-retardant masterbatches: 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 at room temperature for 3 minutes using a high-speed agitator mixer (Henschel Mixer, product 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 using a strand cutter to obtain pellets of the flame-retardant masterbatch.

[0089]

[0090] 2) Fiber Masterbatch: Preparation of Fiber MB-I, II Fiber MB-I, II was prepared by introducing glass fiber (C) from a fiber rack as a fiber bundle into a resin impregnation tank of polypropylene resin (A-6) or (A-7) heated to 270 ° C., and impregnating the glass fiber bundle with polypropylene resin (A-6) or (A-7). The impregnation tank was then drawn through a circular nozzle, cooled, and cut to obtain fiber MB-I pellets (length 10 mm) and fiber MB-II pellets (length 6 mm). The MFR of the polypropylene resin (A-6) or (A-7) in the impregnation tank and the weight ratio of the polypropylene resin (A-6) or (A-7) to the glass fiber of each fiber MB were as shown in Table 2. At this time, 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 as additives per 100 parts by weight of the polypropylene resin (A-6) or (A-7) in the impregnation bath.

[0091]

[0092] 3. Preparation of Test Pieces 1) Examples 1 to 16, Comparative Examples 1 to 8 The various masterbatches and polypropylene-based resins obtained were mixed in the ratios shown in the dry blend ratio column in Tables 3 and 4, and then molded in an injection molding machine and evaluated according to the evaluation methods described above. The final compositions of the propylene-based resin compositions and the obtained evaluation results are shown in Tables 3 and 4.

[0093]

[0094]

[0095] 4. Evaluation Results From the results shown in Tables 3 and 4, the melt flow rate (MFR) of the resin portion was determined for any amount of flame retardant. Ａ It can be seen that the lower the value of MFR, the more improved the fire resistance and flame retardancy. Ａ It can be seen that the fire resistance and flame retardancy improve as the melt flow rate (MFR) of the resin portion decreases. Ａ) is at the same level, but increasing the proportion of flame retardant improves the fire resistance and flame barrier properties. Ａ It is clear that controlling both parameters is important for fire resistance and flame retardancy. On the other hand, the melt flow rate (MFR) of the resin part for a given amount of flame retardant is Ａ If the melt flow rate (MFR) of the resin is reduced to a certain level, the fluidity will decrease, which will hinder the production of actual products. Therefore, in the present invention, the melt flow rate (MFR) of the resin part is set by taking into consideration the balance between fire resistance, flame retardancy, and fluidity. Ａ It is necessary to optimize the amount of fiber and flame retardant. In other words, in Comparative Example 1, the fire resistance and flame retardancy are good, but the fluidity is low, and for practical use, the melt flow rate (MFR) of the resin part is low. Ａ ) is required to be increased. Furthermore, the present invention proposes a composition that is excellent not only in fire resistance, flame retardancy, and fluidity but also in mechanical strength. For example, when the concentration of fiber (C) is reduced as in Comparative Example 8, the mechanical strength decreases. Therefore, in order to propose a composition that is excellent in the balance of fire resistance, flame retardancy, fluidity, and mechanical properties, the concentration of fiber (C) needs to be 30% by weight or more.

[0096] These examples and comparative examples demonstrate that the composition defined in the present application can achieve both high levels of fire resistance and flame retardancy and good fluidity.

Claims

1. A propylene-based resin composition comprising a polypropylene-based resin (A) satisfying the following requirement (A1), a flame retardant (B) satisfying the following requirement (B1), and fibers (C) satisfying the following requirement (C1), and characterized by satisfying the following conditions 1 and 2. Requirement (A1): The polypropylene-based 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 fibers (C) are glass fibers. Requirement 1: The propylene-based resin composition contains 24 to 65% by weight of a polypropylene-based resin (A), 5 to 26% by weight of a flame retardant (B), and 30 to 50% by weight of fibers (C) (provided that the total of the polypropylene-based resin (A), the flame retardant (B), and the fibers (C) is 100% by weight). Condition 2 The melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene resin (A) and the content of the flame retardant (B) (where the total of the polypropylene resin (A), the flame retardant (B), and the fiber (C) is taken as 100% by weight) satisfy either (Condition 2-1) or (Condition 2-2) below. (Condition 2-1) The content of the flame retardant (B) (unit: weight %, where the total of the polypropylene resin (A), the flame retardant (B), and the fiber (C) is taken as 100% by weight) is 5% by weight or more and less than 18% by weight, and the melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene resin (A) is 75 g / 10 min or less. (Condition 2-2) The content of the flame retardant (B) (unit: weight %, where the total of the polypropylene-based resin (A), the flame retardant (B), and the fiber (C) is 100 weight %) is 18 weight % or more and 26 weight % or less, and the melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene-based resin (A) is 105 g / 10 min or less.

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

3. The propylene-based resin composition according to claim 1, wherein the fiber (C) further satisfies the following requirement (C2): Requirement (C2) The fiber (C) is a glass fiber having a fiber length of 1 to 20 mm.

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

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

6. A molded article obtained from the propylene-based resin composition according to any one of claims 1 to 5.

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