Resin composition, flame-retardant masterbatch, and molded article

Abstract

A resin composition according to the present disclosure comprises a thermoplastic resin (A) and a phosphorus-based flame retardant (B). The phosphorus-based flame retardant (B) has a D50 of 11 μm or greater and a D90 of 20 μm or greater. The phosphorus-based flame retardant (B) includes a component (a), which is a specific melamine salt, and a component (b), which is a specific piperazine salt.

Description

Resin composition, flame retardant masterbatch, and molded article

[0001] The present invention relates to a resin composition, a flame retardant masterbatch, and a molded article.

[0002] Polyolefin resins are excellent in mechanical properties (such as bending properties and tensile properties), chemical resistance, molding processability, etc., have a low specific gravity, and are inexpensive. Therefore, their molded articles are used in various applications such as machinery, electrical and electronic equipment, OA equipment, interior and exterior automotive materials, and electric vehicles. In these applications, the molded articles may be required to have flame retardancy. For example, high flame retardancy is required for molded articles used in the housings (frames, casings, exteriors, covers, etc.) of electrical and electronic equipment or OA equipment, cables, etc.

[0003] The flame retardancy of resin products can be enhanced by blending a flame retardant into the resin composition as its material. For example, Patent Document 1 discloses dispersing a phosphorus-based flame retardant with D50 ≤ 10 μm and D95 ≤ 20 μm in a resin material. Also, Patent Document 2 discloses a resin composition containing a thermoplastic resin, a phosphorus-based flame retardant, and a copolymer of an α-olefin and an unsaturated carboxylic acid in a specific ratio.

[0004] Chinese Patent Application Publication No. 115386142, International Publication No. 2021 / 241682

[0005] From the viewpoint of moldability, improvement of the powder fluidity of the resin composition is desired. On the other hand, Patent Documents 1 and 2 do not mention the powder fluidity of the resin composition.

[0006] One aspect of the present invention aims to realize a resin composition with improved powder fluidity.

[0007] To solve the above problems, the present inventors have intensively studied to solve the above problems. As a result, they have found that a resin composition containing a specific phosphorus-based flame retardant has improved powder fluidity, and thus completed the present invention.

[0008] [1] A resin composition comprising a thermoplastic resin (A) and a phosphorus-based flame retardant (B), wherein the cumulative 50% particle size (D50) in the volume-based particle size distribution of the phosphorus-based flame retardant (B) is 11 μm or more, and the cumulative 90% particle size (D90) in the volume-based particle size distribution of the phosphorus-based flame retardant (B) is 20 μm or more, and the phosphorus-based flame retardant (B) contains component (a) and component (b), wherein component (a) is at least one melamine salt selected from the group consisting of melamine orthophosphate, melamine pyrophosphate and melamine polyphosphate, and component (b) is at least one piperazine salt selected from the group consisting of piperazine orthophosphate, piperazine pyrophosphate and piperazine polyphosphate. [2] The resin composition according to [1], wherein the angle of repose of the phosphorus-based flame retardant (B) is 52° or less. [3] The resin composition according to claim [1] or [2], wherein the circularity of the phosphorus-based flame retardant (B), obtained by volume-based particle size distribution measurement, is 0.92 or greater. [4] The resin composition according to any one of [1] to [3], wherein component (a) comprises melamine polyphosphate. [5] The resin composition according to any one of [1] to [4], wherein component (b) comprises piperazine pyrophosphate. [6] The resin composition according to any one of [1] to [5], wherein component (a) comprises melamine polyphosphate and component (b) comprises piperazine pyrophosphate. [7] The resin composition according to [6], comprising 35% to 75% by mass of melamine polyphosphate and 25% to 65% by mass of piperazine pyrophosphate based on the total mass of the phosphorus-based flame retardant (B). [8] The resin composition according to any one of [1] to [7], wherein the thermoplastic resin (A) comprises a polyolefin resin. [9] The resin composition according to [8], wherein the polyolefin resin is mainly composed of polypropylene.

[10] The resin composition according to any one of [1] to [9], further comprising an acid-modified polyolefin resin (C).

[11] The resin composition according to

[10] , wherein the acid-modified polyolefin resin (C) comprises a copolymer of α-olefin and an unsaturated carboxylic acid.

[12] A flame retardant masterbatch, which is a pellet of the resin composition according to any one of [1] to

[11] .

[13] A molded article made from the resin composition according to any one of [1] to

[11] .

[0009] According to one aspect of the present invention, a resin composition with improved powder fluidity can be provided.

[0010] The following describes in detail one aspect of the present invention, but the present invention is not limited to the following aspects without departing from its purpose. In this specification, "~" includes both a lower limit and an upper limit. Furthermore, for each preferred range, the upper limit and lower limit can be used in any combination.

[0011] [Resin Composition] A resin composition according to one aspect of the present invention comprises a thermoplastic resin (A) and a phosphorus-based flame retardant (B).

[0012] [Thermoplastic Resin (A)] There are no particular restrictions on the thermoplastic resin (A), but examples include polyolefin resin, polycarbonate resin, polyester resin, acrylonitrile styrene resin, ABS resin, polyamide resin, modified polyphenylene oxide, etc. One or more types of thermoplastic resin (A) can be used. For example, thermoplastic resin (A) may be a composite resin of two or more types of thermoplastic resins.

[0013] There are no particular restrictions on the polyolefin resin, and examples include the resins described below. There are no particular restrictions on the polyester resin, and examples include polybutylene terephthalate. There are no particular restrictions on the polyamide resin, and examples include nylon 66, nylon 6, etc.

[0014] In a resin composition according to one aspect of the present invention, it is preferable that the thermoplastic resin (A) contains a polyolefin resin, as it is excellent in mechanical properties (bending properties, tensile properties, etc.), chemical resistance, moldability, etc., has a low specific gravity, and is inexpensive.

[0015] In this specification, "polyolefin resin" means a resin in which the proportion of olefin units or cycloolefin units is 90 mol% or more of the total 100 mol% of all constituent units of the resin. Preferably, the proportion of olefin units or cycloolefin units is 95 mol% or more, and more preferably 98 mol% or more, of the total 100 mol% of all constituent units of the polyolefin resin.

[0016] Examples of polyolefin resins include α-olefin polymers such as polyethylene, polypropylene, polybutene, poly(3-methyl-1-butene), poly(3-methyl-1-pentene), and poly(4-methyl-1-pentene); α-olefin copolymers such as ethylene-propylene blocks or random copolymers, α-olefin-propylene blocks or random copolymers having 4 or more carbon atoms, ethylene-methyl methacrylate copolymers, and ethylene-vinyl acetate copolymers; and cycloolefin polymers such as polycyclohexene and polycyclopentene. Examples of polyethylene include low-density polyethylene, linear low-density polyethylene, and high-density polyethylene. Examples of polypropylene include isotactic polypropylene, syndiotactic polypropylene, hemiisotactic polypropylene, and stereoblock polypropylene. In α-olefin-propylene blocks or random copolymers having 4 or more carbon atoms, examples of α-olefins having 4 or more carbon atoms include butene, 3-methyl-1-butene, 3-methyl-1-pentene, and 4-methyl-1-pentene. These polyolefin resins may be used individually or in combination of two or more types.

[0017] The polyolefin resin preferably contains polypropylene. Polypropylene may be used in combination with other polyolefin resins. For example, as the polyolefin resin, a mixture of polypropylene and other α-olefin polymers such as ethylene-propylene blocks or random copolymers, or α-olefin-propylene blocks or random copolymers having 4 or more carbon atoms may be used.

[0018] In terms of lightness, heat resistance, and fluidity, polyolefin resins are preferably composed mainly of polypropylene. The proportion of polypropylene to 100% by mass of polyolefin resin is preferably 50% by mass or more, and more preferably 60% by mass or more. From the viewpoint of flame retardancy, polypropylene is particularly preferred for the polyolefin resin.

[0019] The melt mass flow rate (MFR) of thermoplastic resin (A) is preferably 0.1 g / 10 min or more, more preferably 0.5 g / 10 min or more, while preferably 80 g / 10 min or less, and more preferably 60 g / 10 min or less. If the MFR of thermoplastic resin (A) is above the lower limit, the moldability is better, and if it is below the upper limit, the bending properties, tensile properties, chemical resistance properties, etc. are better. The preferred lower and upper limits can be combined as appropriate (the same applies hereinafter). For example, the MFR of thermoplastic resin (A) may be 0.1 g / 10 min or more and 80 g / 10 min or less, and 0.5 g / 10 min or more and 60 g / 10 min or less. The melt mass flow rate of thermoplastic resin (A) is measured in accordance with JIS K7210, under conditions of a temperature of 230°C and a load of 2.16 kg.

[0020] The ratio of thermoplastic resin (A) to the total mass of the resin composition according to one aspect of the present invention is preferably 20% by mass or more, more preferably 30% by mass or more, more preferably 40% by mass or more, more preferably 45% by mass or more, more preferably 50% by mass or more, and still more preferably 55% by mass or more, while preferably 85% by mass or less, more preferably 75% by mass or less, and still more preferably 65% ​​by mass or less. If the ratio of thermoplastic resin (A) is above the lower limit, the inherent physical properties of thermoplastic resin (A) are more likely to be expressed, and if it is below the upper limit, the flame retardancy is better.

[0021] The ratio of thermoplastic resin (A) to the total mass of the resin composition according to one aspect of the present invention may be, for example, 20% by mass or more and 85% by mass or less (for example, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or 85% by mass), 30% by mass or more and 85% by mass or less, 40% by mass or more and 85% by mass or less, 45% by mass or more and 85% by mass or less, 50% by mass or more and 75% by mass or less, or 55% by mass or more and 65% by mass or less.

[0022] [Phosphorus-based flame retardant (B)] Phosphorus-based flame retardant (B) contains the following components (a) and (b).

[0023] (Component (a)) Component (a) is at least one melamine salt selected from the group consisting of melamine orthophosphate, melamine pyrophosphate, and melamine polyphosphate. It is preferable that component (a) contains melamine polyphosphate in that it further improves the powder flowability of the resin composition.

[0024] The ratio of component (a) to the total mass of phosphorus-based flame retardant (B) is preferably 20% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more, in terms of processability, weather resistance, and flame retardancy. Furthermore, in terms of processability, weather resistance, and flame retardancy, the ratio of component (a) to the total mass of phosphorus-based flame retardant (B) is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less. The range of the ratio of component (a) to the total mass of phosphorus-based flame retardant (B) is preferably 20% by mass or more and 80% by mass or less (for example, 20, 30, 40, 50, 60, 70 or 80% by mass), more preferably 40% by mass or more and 70% by mass or less, and even more preferably 50% by mass or more and 60% by mass or less.

[0025] (Component (b)) Component (b) is at least one piperazine salt selected from the group consisting of piperazine orthophosphate, piperazine pyrophosphate, and piperazine polyphosphate. It is preferable that component (b) contains piperazine pyrophosphate in that it further improves the powder flowability of the resin composition.

[0026] The ratio of component (b) to the total mass of phosphorus-based flame retardant (B) is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more, in terms of corrosion suppression of the processing machine, weather resistance, and flame retardancy. Furthermore, in terms of corrosion suppression of the processing machine, weather resistance, and flame retardancy, the ratio of component (b) to the total mass of phosphorus-based flame retardant (B) is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 50% by mass or less. The range of the ratio of component (b) to the total mass of phosphorus-based flame retardant (B) is preferably 20% by mass or more and 80% by mass or less (for example, 20, 30, 40, 50, 60, 70 or 80% by mass), more preferably 30% by mass or more and 70% by mass or less, and even more preferably 40% by mass or more and 50% by mass or less.

[0027] Components (a) and (b) can be manufactured, for example, by referring to International Publication No. 2019 / 240181 or Japanese Patent Publication No. 2020-105465. Alternatively, commercially available components (a) and (b) may be used.

[0028] The phosphorus-based flame retardant (B) may contain other components in addition to components (a) and (b). Examples of other components include metal oxides such as zinc oxide or zinc compounds.

[0029] The phosphorus-based flame retardant (B) may be obtained by separately incorporating component (a), component (b), and other components as needed into the resin composition, or by mixing component (a), component (b), and other components as needed into the resin composition. It is preferable to obtain the phosphorus-based flame retardant (B) by mixing component (a), component (b), and other components as needed.

[0030] (Preferred combination of component (a) and component (b)) In terms of further improving the powder fluidity of the resin composition, it is preferable that component (a) of the phosphorus-based flame retardant (B) contains melamine polyphosphate and component (b) contains piperazine pyrophosphate.

[0031] In terms of further improving the powder fluidity of the resin composition, the phosphorus-based flame retardant (B) preferably contains 35% to 75% by mass (for example, 35, 40, 45, 50, 55, 60, 65, 70, or 75% by mass), more preferably 50% to 60% by mass, of melamine polyphosphate and preferably 25% to 65% by mass (for example, 25, 30, 35, 40, 45, 50, 55, 60, or 65% by mass), more preferably 40% to 50% by mass, of piperazine pyrophosphate, based on the total mass of the phosphorus-based flame retardant (B).

[0032] The ratio of phosphorus-based flame retardant (B) to thermoplastic resin (A) (100% by mass) is preferably 10% by mass or more, more preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more. Furthermore, the ratio is preferably 400% by mass or less, more preferably 300% by mass or less, more preferably 200% by mass or less, more preferably 100% by mass or less, more preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. By having the ratio of phosphorus-based flame retardant (B) to thermoplastic resin (A) within the above range, it is possible to prevent a significant decrease in mechanical properties and flexural modulus, and to obtain high flame retardancy, especially when used in combination with the acid-modified polyolefin resin (C) described later.

[0033] The ratio of phosphorus-based flame retardant (B) to thermoplastic resin (A) (100% by mass) may be, for example, 10% by mass or more and 400% by mass or less (for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350 or 400% by mass), 10% by mass or more and 300% by mass or less, 10% by mass or more and 200% by mass or less, 10% by mass or more and 100% by mass or less, 30% by mass or more and 90% by mass or less, 50% by mass or more and 80% by mass or less, or 60% by mass or more and 70% by mass or less.

[0034] The ratio of the phosphorus-based flame retardant (B) to the total mass of the resin composition according to one aspect of the present invention is preferably 15% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, while preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. If the ratio of the phosphorus-based flame retardant (B) is above the lower limit, the flame retardancy is better, and if it is below the upper limit, the inherent physical properties of the thermoplastic resin (A) are more easily expressed.

[0035] The ratio of the phosphorus-based flame retardant (B) to the total mass of the resin composition according to one aspect of the present invention may be, for example, 15% by mass or more and 70% by mass or less (for example, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, or 70% by mass), 20% by mass or more and 60% by mass or less, or 30% by mass or more and 50% by mass or less.

[0036] (Physical properties of phosphorus-based flame retardant (B)) The cumulative 50% particle size (D50) in the volume-based particle size distribution of phosphorus-based flame retardant (B) is 11 μm or more, and the cumulative 90% particle size (D90) in the volume-based particle size distribution of phosphorus-based flame retardant (B) is 20 μm or more. The fact that D50 and D90 of phosphorus-based flame retardant (B) are within the above range improves the powder flowability of the resin composition. Phosphorus-based flame retardant (B) with a large particle size has relatively low cohesive forces between particles (e.g., van der Waals forces, electrostatic forces, etc.), making it difficult for particles to adhere to each other. In addition, the large particle size of phosphorus-based flame retardant (B) increases the porosity when deposited, ensuring air passages, thus improving the powder flowability of the resin composition containing phosphorus-based flame retardant (B).

[0037] The phosphorus-based flame retardant (B) may have a D50 of 11 μm or more (for example, 12 μm or more) and a D90 of 21 μm or more (for example, 22 μm, 24 μm, 26 μm, 28 μm, or 29 μm or more).

[0038] In terms of further improving the powder fluidity of the resin composition, the maximum particle size (Dmax) in the volume-based particle size distribution of the phosphorus-based flame retardant (B) is preferably 30 μm or more, more preferably 32 μm or more, and even more preferably 34 μm or more.

[0039] The above D50 and D90 can be measured by the laser scattering method. Also, the above Dmax can be measured by the image analysis method.

[0040] The volume-based particle size distribution of the phosphorus-based flame retardant (B) can be controlled, for example, by referring to paragraphs 0050 to 0053 of WO 2022 / 131284.

[0041] The angle of repose of the phosphorus-based flame retardant (B) may be 52° or less, may be 51° or less, or may be 50° or less. The angle of repose can be measured by a powder tester. The fact that the angle of repose is within these ranges indicates that the phosphorus-based flame retardant (B) has better fluidity, and thus the powder fluidity of the resin composition is good.

[0042] The roundness obtained by measuring the volume-based particle size distribution of the phosphorus-based flame retardant (B) may be 0.92 or more, may be 0.93 or more, or may be 0.95 or more. The fact that the roundness is within these ranges is considered to reduce the contact area and friction between the phosphorus-based flame retardants (B), resulting in better fluidity of the phosphorus-based flame retardant (B) and, consequently, good powder fluidity of the resin composition.

[0043] The roundness can be measured by the image analysis method and is calculated by the following formula (1). Roundness = 4πS / L ２ In formula (1), S is the projected cross-sectional area of the phosphorus-based flame retardant (B), and L is the perimeter of the phosphorus-based flame retardant (B).

[0044] The apparent specific gravity of the phosphorus-based flame retardant (B) may be less than 0.4 g / cc or may be 0.39 g / cc or less. The apparent specific gravity can be measured by a powder tester.

[0045] When the phosphorus-based flame retardant (B) is heated at a rate of 10 °C / min in thermogravimetric analysis, the weight retention rate at 300 °C (the ratio of the weight of the phosphorus-based flame retardant (B) after heating to the weight of the phosphorus-based flame retardant (B) before heating) may be 86% or more, may be 88% or more, or may be 90% or more. When the particle size of the phosphorus-based flame retardant (B) is larger, the specific surface area is smaller and the thermal decomposition temperature is higher. Therefore, when the thermal decomposition temperature is within these ranges, it is considered that the phosphorus-based flame retardant (B) has better fluidity, and thus the powder fluidity of the resin composition is good.

[0046] [Acid-modified polyolefin resin (C)] In terms of enhancing the dispersibility of the phosphorus-based flame retardant (B) in the thermoplastic resin (A), the resin composition according to one aspect of the present invention preferably further contains an acid-modified polyolefin resin (C). Further, by including the acid-modified polyolefin resin (C) in the resin composition, a resin composition containing the phosphorus-based flame retardant (B) at a high concentration can be obtained. In the present specification, "acid-modified polyolefin resin (C)" means a polyolefin having a structure chemically modified with an acidic monomer. For example, it is a compound in which polypropylene or polyethylene is chemically bonded to an unsaturated carboxylic acid, or a copolymer of an α-olefin and an unsaturated carboxylic acid (hereinafter also referred to as "copolymer").

[0047] In terms of further enhancing the dispersibility of the phosphorus-based flame retardant (B) in the thermoplastic resin (A), the acid-modified polyolefin resin (C) preferably contains a copolymer of an α-olefin and an unsaturated carboxylic acid.

[0048] The copolymer means a copolymer in which the ratio of the α-olefin unit to the total of 100 mol% of the α-olefin unit and the unsaturated carboxylic acid unit is 20 mol% or more and 80 mol% or less (for example, 20, 30, 40, 50, 60, 70 or 80 mol%). In the copolymer, the ratio of the α-olefin unit to the total of 100 mol% of the α-olefin unit and the unsaturated carboxylic acid unit is preferably 30 mol% or more from the viewpoint of enhancing the compatibility between the copolymer and the thermoplastic resin (A), and preferably 70 mol% or less from the viewpoint of enhancing the compatibility between the copolymer and the phosphorus-based flame retardant (B).

[0049] In copolymers, the number of carbon atoms in the α-olefin is preferably 5 to 80 (for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80). If the number of carbon atoms in the α-olefin is 5 or more, compatibility with polyolefin resins tends to be better, and if it is 80 or less, raw material costs tend to be better. For these reasons, the lower limit of the number of carbon atoms in the α-olefin is more preferably 10 or more, more preferably 12 or more, more preferably 15 or more, and even more preferably 18 or more. Also, for the reasons mentioned above, the upper limit of the number of carbon atoms in the α-olefin is more preferably 70 or less, and even more preferably 60 or less.

[0050] In copolymers, α,β-unsaturated carboxylic acids are preferred as unsaturated carboxylic acids from the viewpoint of incorporating hydrophilic functional groups into the main chain of the copolymer or directly bonding them to it to exhibit good compatibility with phosphorus-based flame retardants (B). Examples of α,β-unsaturated carboxylic acids include (meth)acrylic acid, maleic acid, methylmaleic acid, fumaric acid, methylfumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, glutaconic acid, norbornane-5-ene-2,3-dicarboxylic acid, and esters, anhydrides, and imides of these unsaturated carboxylic acids. "(meth)acrylic acid" refers to acrylic acid or methacrylic acid.

[0051] Specific examples of esters, anhydrides, or imides of unsaturated carboxylic acids include (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and glycidyl (meth)acrylate; dicarboxylic acid anhydrides such as maleic anhydride, itaconic anhydride, citraconic anhydride, and 5-norbornene-2,3-dicarboxylic acid anhydride; and maleimide compounds such as maleimide, N-ethylmaleimide, and N-phenylmaleimide.

[0052] As the aforementioned unsaturated carboxylic acids, one of these may be used alone, or two or more may be used in combination. Among these, from the viewpoint of copolymerization reactivity, esters of unsaturated carboxylic acids or dicarboxylic acid anhydrides are preferred. In particular, from the viewpoint of compatibility with phosphorus-based flame retardants (B), dicarboxylic acid anhydrides are preferred, and maleic anhydride is especially preferred.

[0053] The weight-average molecular weight of the copolymer is preferably 2,000 or more, more preferably 3,000 or more, while preferably 50,000 or less, and more preferably 30,000 or less. If the weight-average molecular weight of the copolymer is within the above upper and lower limit range, the dispersibility of the phosphorus-based flame retardant (B) is better. The weight-average molecular weight of the copolymer may be, for example, 2,000 or more and 50,000 or less (for example, 2,000, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000, 9,000, 10,000, 15,000, 20,000, 25,000, 30,000, 35,000, 40,000, 45,000 or 50,000), and may be 3,000 or more and 30,000 or less. The weight-average molecular weight of the copolymer is a value on a standard polystyrene basis, measured by gel permeation chromatography after dissolving the copolymer in tetrahydrofuran (THF).

[0054] Examples of commercially available copolymers include Recolve® CE2 (manufactured by Clariant Japan Co., Ltd.) and Diacarna® 30M (manufactured by Mitsubishi Chemical Corporation).

[0055] The ratio of acid-modified polyolefin resin (C) to the total mass of the resin composition can be appropriately determined from the viewpoint of sufficiently dispersing the phosphorus-based flame retardant (B). From the viewpoint of improving the tensile properties of the resin composition, this ratio is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 4% by mass or less, and still preferably 3% by mass or less. Furthermore, from the viewpoint of good dispersion of the phosphorus-based flame retardant (B) in the resin composition, this ratio is preferably 1% by mass or more, more preferably 1.5% by mass or more, and still preferably 2% by mass or more. The range of the ratio of acid-modified polyolefin resin (C) to the total mass of the resin composition is preferably 1% by mass or more and 10% by mass or less (for example, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9 or 10% by mass), more preferably 1.5% by mass or more and 5% by mass or less, and still preferably 2% by mass or more and 4% by mass or less.

[0056] The ratio of acid-modified polyolefin resin (C) to phosphorus-based flame retardant (B) being within the above range allows for the production of a resin product with high flame retardancy while maintaining high mechanical strength and high flexural modulus when the resin composition according to one aspect of the present invention is used as a flame retardant masterbatch described later. From the above viewpoint, the ratio of acid-modified polyolefin resin (C) to phosphorus-based flame retardant (B) in the resin composition may be, for example, 15% by mass or less, 10% by mass or less, 8% by mass or less, 6% by mass or less, 1% by mass or more, 2% by mass or more, 3% by mass or more, 4% by mass or more, or 5% by mass or more. The range of the ratio of acid-modified polyolefin resin (C) to phosphorus-based flame retardant (B) in the resin composition may be, for example, 1% by mass or more and 15% by mass or less (for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15% by mass).

[0057] The ratio of phosphorus-based flame retardant (B) to acid-modified polyolefin resin (C) is preferably 15 or more, and more preferably 18 or more, from the viewpoint of obtaining a resin product with high flame retardancy while maintaining high mechanical strength and high flexural modulus when the resin composition according to one aspect of the present invention is used as a flame retardant masterbatch described later. From the viewpoint of the stability of the composition as a masterbatch or the stability of the performance of the flame retardant masterbatch, the ratio is preferably 25 or less, more preferably 23 or less, and even more preferably 20 or less. The range of the ratio of phosphorus-based flame retardant (B) to acid-modified polyolefin resin (C) is preferably 15 or more and 25 or less (for example, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25), and more preferably 18 or more and 23 or less.

[0058] The ratio of the total mass of the thermoplastic resin (A), phosphorus-based flame retardant (B), and acid-modified polyolefin resin (C) to the total mass of the resin composition according to one aspect of the present invention is not particularly limited, but a higher ratio is preferable from the viewpoint of increasing the freedom of composition when used as a flame retardant masterbatch as described later. From this viewpoint, the ratio is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 99% by mass or more.

[0059] [Other Components] A resin composition according to one aspect of the present invention may further contain other components besides the thermoplastic resin (A), phosphorus-based flame retardant (B), and acid-modified polyolefin resin (C), to the extent that the effects of the present invention are obtained. The other components may be one or two or more, and their type and amount may be appropriately determined to the extent that both the effects of the present invention and the effects of the other components are obtained. Examples of other components include other flame retardants and flame retardant aids other than the phosphorus-based flame retardant (B); inorganic fiber fillers (D); antioxidants; ultraviolet absorbers; light stabilizers; anti-aging agents; crystal nucleating agents; plasticizers; fluorine-containing anti-dropping agents; and the like.

[0060] (Other flame retardants and flame retardant aids besides phosphorus-based flame retardant (B)) Other flame retardants or flame retardant aids other than phosphorus-based flame retardant (B) that may be included in the resin composition according to one embodiment of the present invention are preferably organic or inorganic flame retardants or flame retardant aids that do not contain halogens. Examples of such flame retardants or flame retardant aids include triazine ring-containing compounds, silicone-based flame retardants, metal hydroxides, metal oxides, boric acid compounds, and expandable graphite. These flame retardants or flame retardant aids may be used individually or in combination of two or more.

[0061] Examples of triazine ring-containing compounds include melamine, ammeline, benzguanamine, acetoguanamine, phthalodiguanamine, melamine cyanurate, butylenediguanamine, norbornenediguanamine, methylenediguanamine, ethylenedimelamine, trimethylenedimelamine, tetramethylenedimelamine, hexamethylenedimelamine, and 1,3-hexylenedimelamine.

[0062] Examples of silicone-based flame retardants include silicone oil, silicone rubber, and silicone resin.

[0063] Examples of metal hydroxides include magnesium hydroxide, aluminum hydroxide, calcium hydroxide, barium hydroxide, zinc hydroxide, and Kissmer 5A (a trademark for magnesium hydroxide manufactured by Kyowa Chemical Industry Co., Ltd.).

[0064] Examples of metal oxides include inorganic compounds such as zinc oxide, titanium oxide, aluminum oxide, magnesium oxide, titanium dioxide, and hydrotalcite, as well as surface-treated products thereof. Specific examples of metal oxides include TIPAQUE R-680 (trademark for titanium oxide manufactured by Ishihara Sangyo Co., Ltd.), Kyowa Mag 150 (trademark for magnesium oxide manufactured by Kyowa Chemical Industry Co., Ltd.), DHT-4A (hydrotalcite: manufactured by Kyowa Chemical Industry Co., Ltd.), and Alkamizer 4 (trademark for zinc-modified hydrotalcite manufactured by Kyowa Chemical Industry Co., Ltd.).

[0065] Examples of boric acid compounds include zinc borate.

[0066] (Inorganic fiber filler (D)) An inorganic fiber filler (D) which may be included in the resin composition according to one aspect of the present invention is at least one inorganic fiber filler (D) selected from the group consisting of glass fibers and carbon fibers.

[0067] The type of glass fiber is not particularly limited; any type of glass fiber, such as E-glass, C-glass, S-glass, or D-glass, can be used.

[0068] The form of the glass fibers is not particularly limited, and any type of glass fiber such as chopped strands, roving, yarn, or glass wool can be used, however, chopped strands and glass wool are preferred in terms of workability.

[0069] The type of carbon fiber is not particularly limited; any carbon fiber such as polyacrylonitrile (PAN) carbon fiber, pitch carbon fiber, or graphite fiber can be used.

[0070] The form of the carbon fiber is not particularly limited, and any carbon fiber such as filament, regular tow, large tow, stable yarn, or chopped strand can be used, but chopped strand is preferred in terms of workability.

[0071] When a resin composition according to one aspect of the present invention contains an inorganic fiber filler (D), the ratio of the inorganic fiber filler (D) to the total mass of the resin composition is preferably 0.01% by mass or more, and more preferably 0.1% by mass or more. Furthermore, the ratio is preferably 50% by mass or less, more preferably 40% by mass or less, more preferably 30% by mass or less, more preferably 25% by mass or less, more preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less. The range of the ratio of the inorganic fiber filler (D) to the total mass of the resin composition is preferably 0.01% by mass or more and 50% by mass or less (for example, 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45 or 50% by mass), and more preferably 0.1% by mass or more and 40% by mass or less. If the proportion of inorganic fiber filler (D) is above the lower limit, lip-preventing and smoke-suppressing effects are easily obtained, and if it is below the upper limit, the inherent properties of the thermoplastic resin (A) are less likely to be impaired.

[0072] If the resin composition according to one aspect of the present invention contains an inorganic fiber filler (D), it may further contain an interfacial strength enhancer (E) for the inorganic fiber filler (D).

[0073] (Interfacial Strength Enhancer (E)) As the interfacial strength enhancer (E), polymers having an olefin skeleton (excluding polyolefin resins and copolymers) are preferred, particularly in terms of compatibility with thermoplastic resins (A) such as polyolefin resins. The interfacial strength is further improved by the compatibility of the olefin skeleton with the polyolefin resin.

[0074] The interfacial strength enhancer (E) preferably has an acidic group. The reaction between the inorganic fibrous filler (D) and the acidic group further improves the interfacial strength.

[0075] Examples of acidic groups include carboxyl groups, carboxylic acid anhydride groups, sulfonic acid groups, sulfinic acid groups, phosphonic acid groups, and phosphinic acid groups. Preferably, at least one selected from the group consisting of carboxyl groups, carboxylic acid anhydride groups, sulfonic acid groups, sulfinic acid groups, phosphonic acid groups, and phosphinic acid groups is preferred, more preferably at least one selected from the group consisting of carboxyl groups, carboxylic acid anhydride groups, and phosphonic acid groups is preferred, and even more preferably at least one selected from the group consisting of carboxyl groups and carboxylic acid anhydride groups.

[0076] Methods for producing an interfacial strength improver (E) having an olefin skeleton and acidic groups include: (1) a method of reducing the molecular weight of an olefin resin by thermal decomposition at high temperature, followed by the addition of a compound or monomer having an acidic group; (2) a method of polymerizing a low molecular weight olefin resin, followed by the addition of a compound or monomer having an acidic group; and (3) a method of copolymerizing an α-olefin with a compound or monomer having an acidic group. Polymerization methods can include radical polymerization methods such as solution polymerization, emulsion polymerization, suspension polymerization, and bulk polymerization, as well as living polymerization. Furthermore, a method of forming macromonomers first and then polymerizing them is also possible.

[0077] Examples of compounds or monomers having an acidic group include acrylic acid, methacrylic acid, maleic acid, fumaric acid, maleic anhydride, and citraconic anhydride, with maleic anhydride being particularly preferred.

[0078] Examples of commercially available interfacial strength improvers (E) include Yumex 1001 and 1010 (manufactured by Sanyo Chemical Industries, Ltd.), and Kayabrid 002PP and 003PP (manufactured by Kayaku Nurion Co., Ltd.).

[0079] A resin composition according to one aspect of the present invention may contain other fillers besides the inorganic fiber filler (D). Other fillers can be fibrous, plate-like, granular, or powdered. Specifically, inorganic fibrous reinforcing materials such as asbestos fibers, metal fibers, potassium titanate whiskers, aluminum borate whiskers, magnesium-based whiskers, silicon-based whiskers, warlastenite, sepiolite, asbestos, slag fibers, zonolite, elestadite, gypsum fibers, silica fibers, silica-alumina fibers, zirconia fibers, boron nitride fibers, silicon nitride fibers, and boron fibers, polyester fibers, nylon fibers, acrylic fibers, regenerated cellulose fibers, acetate fibers, kenaf, ramie, cotton, jute, hemp, sisal, flax, linen, etc. Examples of reinforcing materials include organic fibrous materials such as silk, Manila hemp, sugarcane, wood pulp, paper waste, recycled paper, and wool; glass flakes, non-swelling mica, graphite, metal foil, ceramic beads, clay, mica, sericite, zeolite, bentonite, dolomite, kaolin, fine silica powder, feldspar powder, potassium titanate, shirasu balloons, calcium carbonate, magnesium carbonate, barium sulfate, calcium oxide, aluminum oxide, titanium oxide, titanium dioxide, aluminum silicate, gypsum, novaculite, dawsonite, and white clay, which can be in the form of plates or granules. These fillers may be coated or bundled with thermoplastic resins such as ethylene-vinyl acetate copolymers or thermosetting resins such as epoxy resins, or treated with coupling agents such as aminosilanes or epoxysilanes.

[0080] The content of other fillers is preferably 10 parts by mass or more, and more preferably 20 parts by mass or more, per 100 parts by mass of the synthetic resin component in the resin composition. Furthermore, the content is preferably 60 parts by mass or less, and more preferably 50 parts by mass or less. The range of the content of other fillers per 100 parts by mass of the synthetic resin component in the resin composition is preferably 10 parts by mass or more and 60 parts by mass or less (for example, 10, 20, 30, 40, 50 or 60 parts by mass), and more preferably 20 parts by mass or more and 50 parts by mass or less.

[0081] (Antioxidants) Examples of antioxidants that may be included in the resin composition according to one embodiment of the present invention include phenolic antioxidants, phosphorus-based antioxidants, and thioether-based antioxidants.

[0082] Examples of phenolic antioxidants include 2,6-di-tert-butyl-p-cresol, 2,6-diphenyl-4-octadecyloxyphenol, distearyl(3,5-di-tert-butyl-4-hydroxybenzyl)phosphonate, 1,6-hexamethylenebis[(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], 4,4'-thiobis(6-tert-butyl-m-cresol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), and 4,4'- Tylidenebis(6-tertiary butyl-m-cresol), 2,2'-ethylidenebis(4,6-ditertiary butylphenol), 2,2'-ethylidenebis(4-secondary butyl-6-tertiary butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-tertiary butylphenyl)butane, 1,3,5-tris(2,6-dimethyl-3-hydroxy-4-tertiary butylbenzyl) isocyanurate, 1,3,5-tris(3,5-ditertiary butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris(3,5-ditertiary butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris(3,5-ditertiary butyl-4-hydroxybenzyl) Zyl)-2,4,6-trimethylbenzene, 2-tert-butyl-4-methyl-6-(2-acryloyloxy-3-tert-butyl-5-methylbenzyl)phenol, stearyl(3,5-ditert-butyl-4-hydroxyphenyl)propionate, tetrakis[3-(3,5-ditert-butyl-4-hydroxyphenyl)propionate methyl]methane, thiodiethylene glycol bis[(3,5-ditert-butyl-4-hydroxyphenyl)propionate], 1,6-hexamethylene bis[(3,5-ditert-butyl-4-hydroxyphenyl)propionate] ], bis[3,3-bis(4-hydroxy-3-tertiary butylphenyl)butyric acid] glycol ester, bis[2-tertiary butyl-4-methyl-6-(2-hydroxy-3-tertiary butyl-5-methylbenzyl)phenyl] terephthalate, 1,3,5-tris[(3,5-ditertiary butyl-4-hydroxyphenyl)propionyloxyethyl] isocyanurate, 3,9-bis[1,1-dimethyl-2-{(3-tertiary butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5,5) Examples include undecane, triethylene glycol bis[(3-tertiary butyl-4-hydroxy-5-methylphenyl)propionate], etc.

[0083] The content of the phenolic antioxidant is preferably 0.001 parts by mass or more, and more preferably 0.05 parts by mass or more, per 100 parts by mass of the synthetic resin component in the resin composition. Furthermore, the content is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less. The range of the content of the phenolic antioxidant per 100 parts by mass of the synthetic resin component in the resin composition is preferably 0.001 parts by mass or more and 10 parts by mass or less (for example, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts by mass), and more preferably 0.05 parts by mass or more and 5 parts by mass or less.

[0084] Examples of phosphorus-based antioxidants include trisnonylphenyl phosphite, tris[2-tert-butyl-4-(3-tert-butyl-4-hydroxy-5-methylphenylthio)-5-methylphenyl] phosphite, tridecyl phosphite, octyl diphenyl phosphite, di(decyl)monophenyl phosphite, di(tridecyl)pentaerythritol diphosphite, di(nonylphenyl)pentaerythritol diphosphite, and bis(2,4-ditert-butylphenyl phosphite). Penyl) Pentaerythritol Diphosphite, Bis(2,6-Diter-butyl-4-methylphenyl) Pentaerythritol Diphosphite, Bis(2,4,6-Triter-butylphenyl) Pentaerythritol Diphosphite, Bis(2,4-Dicumylphenyl) Pentaerythritol Diphosphite, Tetra(tridecyl) Isopropylidene Diphenol Diphosphite, Tetra(tridecyl)-4,4'-n-Butylidene Bis(2-Terter-butyl-5-methylphenyl) (Ir) diphosphite, hexa(tridecyl)-1,1,3-tris(2-methyl-4-hydroxy-5-tertiary butylphenyl)butane triphosphite, tetrakis(2,4-ditertiary butylphenyl) biphenylenediphosphonite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2,2'-methylenebis(4,6-tertiary butylphenyl)-2-ethylhexyl phosphite, 2,2'-methylenebis(4,6-tertiary butylphenyl) Examples include phenyl)-octadecyl phosphite, 2,2'-ethylidenebis(4,6-diter-butylphenyl)fluorophosphite, tris(2-[(2,4,8,10-tetrakister-butyldibenzo[d,f][1,3,2]dioxaphosphine-6-yl)oxy]ethyl)amine, phosphite of 2-ethyl-2-butylpropylene glycol and 2,4,6-triter-butylphenol, and tris(2,4-di-ter-butylphenyl) phosphite.

[0085] The content of the phosphorus-based antioxidant is preferably 0.001 parts by mass or more, and more preferably 0.05 parts by mass or more, per 100 parts by mass of the synthetic resin component in the resin composition. Furthermore, the content is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less. The range of the content of the phosphorus-based antioxidant per 100 parts by mass of the synthetic resin component in the resin composition is preferably 0.001 parts by mass or more and 10 parts by mass or less (for example, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts by mass), and more preferably 0.05 parts by mass or more and 5 parts by mass or less.

[0086] Examples of thioether-based antioxidants include dialkylthiodipropionates such as dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiodipropionate, as well as pentaerythritol tetra(β-alkylthiopropionate esters).

[0087] The content of the thioether antioxidant is preferably 0.001 parts by mass or more, and more preferably 0.05 parts by mass or more, per 100 parts by mass of the synthetic resin component in the resin composition. Furthermore, the content is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less. The range of the content of the thioether antioxidant per 100 parts by mass of the synthetic resin component in the resin composition is preferably 0.001 parts by mass or more and 10 parts by mass or less (for example, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts by mass), and more preferably 0.05 parts by mass or more and 5 parts by mass or less.

[0088] (UV absorbers) UV absorbers that may be included in the resin composition according to one aspect of the present invention include, for example, 2-hydroxybenzophenones such as 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 5,5'-methylenebis(2-hydroxy-4-methoxybenzophenone); 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-diter-butylphenyl)-5-chlorobenzotriazole 2-(2'-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-dicumylphenyl)benzotriazole, 2,2'-methylenebis(4-tert-octyl-6-(benzotriazolyl)phenol), 2-(2'-hydroxy-3'-tert-butyl-5'-carboxyphenyl)benzotriazole, etc. Triazoles; Benzoates such as phenyl salicylate, resorcinol monobenzoate, 2,4-diter-butylphenyl-3,5-diter-butyl-4-hydroxybenzoate, 2,4-diter-amylphenyl-3,5-diter-butyl-4-hydroxybenzoate, hexadecyl-3,5-diter-butyl-4-hydroxybenzoate; Substituted oxanilides such as 2-ethyl-2'-ethoxyoxanilide and 2-ethoxy-4'-dodecyloxanilide; Ethyl-α-cyano-β,β-diphenylacrylate Examples include cyanoacrylates such as methyl-2-cyano-3-methyl-3-(p-methoxyphenyl)acrylate; and triaryltriazines such as 2-(2-hydroxy-4-octoxyphenyl)-4,6-bis(2,4-diter-butylphenyl)-s-triazine, 2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-s-triazine, and 2-(2-hydroxy-4-propoxy-5-methylphenyl)-4,6-bis(2,4-diter-butylphenyl)-s-triazine.

[0089] The amount of ultraviolet absorber is preferably 0.001 parts by mass or more, and more preferably 0.05 parts by mass or more, per 100 parts by mass of the synthetic resin component in the resin composition. Furthermore, the amount is preferably 30 parts by mass or less, and more preferably 10 parts by mass or less. The range of the amount of ultraviolet absorber per 100 parts by mass of the synthetic resin component in the resin composition is preferably 0.001 parts by mass or more and 30 parts by mass or less (for example, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, or 30 parts by mass), and more preferably 0.05 parts by mass or more and 10 parts by mass or less.

[0090] (Light stabilizers) Examples of light stabilizers that may be included in the resin composition according to one embodiment of the present invention include 2,2,6,6-tetramethyl-4-piperidyl stearate, 1,2,2,6,6-pentamethyl-4-piperidyl stearate, 2,2,6,6-tetramethyl-4-piperidyl benzoate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, tetrakis(2,2,6,6 Bis(1,2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, bis(1,2,2,6,6-tetramethyl-4-piperidyl)-di(tridecyl)-1,2,3,4-butanetetracarboxylate, bis(1,2,2,4,4-pentamethyl-4-piperidyl)-2- Tyl-2-(3,5-diter-butyl-4-hydroxybenzyl)malonate, 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-piperidinol / diethyl succinate polycondensate, 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane / 2,4-dichloro-6-morpholino-s-triazine polycondensate, 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane / 2,4-dichloro-6-ter-octylamino-s-triazine polycondensate, 1,5,8,12-tetrakis[2,4-bi [N-butyl-N-(2,2,6,6-tetramethyl-4-piperidyl)amino)-s-triazine-6-yl]-1,5,8,12-tetraazadodecane, 1,5,8,12-tetrakis[2,4-bis(N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino)-s-triazine-6-yl]-1,5,8,12-tetraazadodecane, 1,6,11-tris[2,4-bis(N-butyl-N-(2,2,6,6-tetramethyl-4-piperidyl)amino)-s-triazine-6-yl]aminoundecane, 1,6,Examples of hindered amine compounds include 11-tris[2,4-bis(N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino)-s-triazine-6-yl]aminoundecane.

[0091] The content of the light stabilizer is preferably 0.001 parts by mass or more, and more preferably 0.05 parts by mass or more, per 100 parts by mass of the synthetic resin component in the resin composition. Furthermore, the content is preferably 30 parts by mass or less, and more preferably 10 parts by mass or less. The range of the content of the light stabilizer per 100 parts by mass of the synthetic resin component in the resin composition is preferably 0.001 parts by mass or more and 30 parts by mass or less (for example, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, or 30 parts by mass), and more preferably 0.05 parts by mass or more and 10 parts by mass or less.

[0092] (Nurturing agent) As a nucleating agent that may be included in the resin composition according to one aspect of the present invention, those commonly used as nucleating agents for polyolefin resins can be used as appropriate, for example, inorganic nucleating agents and organic nucleating agents.

[0093] Specific examples of inorganic nucleating agents include kaolinite, synthetic mica, clay, zeolite, graphite, carbon black, magnesium oxide, titanium oxide, calcium sulfide, boron nitride, calcium carbonate, barium sulfate, aluminum oxide, neodymium oxide, and metal salts such as phenylphosphonate. These inorganic nucleating agents may be modified with organic substances to improve their dispersibility in the composition.

[0094] Specific examples of organic crystal nucleating agents include sodium benzoate, potassium benzoate, lithium benzoate, calcium benzoate, magnesium benzoate, barium benzoate, lithium terephthalate, sodium terephthalate, potassium terephthalate, calcium oxalate, sodium laurate, potassium laurate, sodium myristate, potassium myristate, calcium myristate, sodium octacosanoate, calcium octacosanoate, sodium stearate, potassium stearate, lithium stearate, calcium stearate, magnesium stearate, barium stearate, sodium montanaate, calcium montanaate, sodium tolulate, sodium salicylate, potassium salicylate, and salicylic acid. Examples include metal salts of organic carboxylic acids such as zinc, aluminum dibenzoate, potassium dibenzoate, lithium dibenzoate, sodium β-naphthalate, and sodium cyclohexanecarboxylate; organic sulfonates such as sodium p-toluenesulfonate and sodium sulfisophthalate; carboxylic acid amides such as stearic acid amide, ethylenebislauric acid amide, palmitic acid amide, hydroxystearic acid amide, erucic acid amide, and tris(t-butylamide) trimesic acid; benzylidene sorbitol and its derivatives; metal salts of phosphorus compounds such as sodium-2,2'-methylenebis(4,6-di-t-butylphenyl)phosphate; and sodium 2,2-methylbis(4,6-di-t-butylphenyl).

[0095] (Plasticizer) Plasticizers that may be included in the resin composition according to one aspect of the present invention can be those commonly used as plasticizers for polyolefin resins, such as polyester plasticizers, glycerin plasticizers, polycarboxylic acid ester plasticizers, polyalkylene glycol plasticizers, epoxy plasticizers, etc. These plasticizers may be used individually or in combination of two or more.

[0096] Specific examples of polyester plasticizers include polyesters composed of acid components such as adipic acid, sebatic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, and rosin, and diol components such as propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, ethylene glycol, and diethylene glycol, as well as polyesters composed of hydroxycarboxylic acids such as polycaprolactone. These polyesters may have their ends sealed with monofunctional carboxylic acids or monofunctional alcohols, or with epoxy compounds, etc.

[0097] Specific examples of glycerin-based plasticizers include glycerin monoacetomolaurate, glycerin diacetomolaurate, glycerin monoacetomostearate, glycerin diacetomooleate, and glycerin monoacetomomonomonate. Specific examples of polycarboxylic acid ester plasticizers include phthalate esters such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, diheptyl phthalate, dibenzyl phthalate, and butylbenzyl phthalate; trimellitic acid esters such as tributyl trimellitic acid, trioctyl trimellitic acid, and trihexyl trimellitic acid; adipic acid esters such as diisodecyl adipate, n-octyl-n-decyl adipate, methyl diglycol butyl diglycol adipate, benzyl methyl diglycol adipate, and benzyl butyl diglycol adipate; citrate esters such as triethyl acetyl citrate and tributyl acetyl citrate; azelaic acid esters such as di-2-ethylhexyl azelaic acid; sebacate esters such as dibutyl sebacate and di-2-ethylhexyl sebacate.

[0098] Specific examples of polyalkylene glycol-based plasticizers include polyethylene glycol, polypropylene glycol, poly(ethylene oxide / propylene oxide) block and / or random copolymer, polytetramethylene glycol, ethylene oxide addition polymers of bisphenols, propylene oxide addition polymers of bisphenols, tetrahydrofuran addition polymers of bisphenols, and other polyalkylene glycols, or end-binding compounds such as their terminal epoxy-modified compounds, terminal ester-modified compounds, and terminal ether-modified compounds.

[0099] Epoxy plasticizers generally refer to epoxy triglycerides composed of alkyl epoxy stearate and soybean oil, but other types of epoxy resins, mainly made from bisphenol A and epichlorohydrin, can also be used. Specific examples of other plasticizers include benzoic acid esters of aliphatic polyols such as neopentyl glycol dibenzoate, diethylene glycol dibenzoate, and triethylene glycol di-2-ethyl butyrate, fatty acid amides such as stearic acid amide, aliphatic carboxylic acid esters such as butyl oleate, oxy acid esters such as methyl acetylricinoleate and butyl acetylricinoleate, pentaerythritol, various sorbitols, polyacrylic acid esters, and paraffins.

[0100] (Fluorine-containing anti-dripping agent) An example of a fluorine-containing anti-dripping agent that may be included in the resin composition according to one aspect of the present invention is a fluorine-containing polymer having fibril-forming ability. Examples of such fluorine-containing polymers include polytetrafluoroethylene (hereinafter also referred to as "PTFE"), tetrafluoroethylene copolymers (for example, tetrafluoroethylene / hexafluoropropylene copolymers), partially fluorinated polymers as shown in U.S. Patent No. 4,379,910, and polycarbonate resins produced from fluorinated diphenols. PTFE is preferred among these.

[0101] PTFE having fibril-forming ability has an extremely high molecular weight and tends to bond with other PTFE particles to form fibers when subjected to external forces such as shear force. The molecular weight is preferably 1 million or more, and more preferably 2 million or more, based on the number average molecular weight determined from the standard specific gravity. Furthermore, the number average molecular weight is preferably 10 million or less, and more preferably 9 million or less. The range of the number average molecular weight of PTFE having fibril-forming ability is preferably 1 million to 10 million (for example, 1 million, 2 million, 3 million, 4 million, 5 million, 6 million, 7 million, 8 million, 9 million, or 10 million), and more preferably 2 million to 9 million.

[0102] PTFE with fibril-forming ability can be used in solid form as well as in aqueous dispersion form.

[0103] Examples of commercially available PTFE products with fibril-forming ability include Teflon® 6J from Mitsui DuPont Fluorochemicals Co., Ltd., and Polyflon® MPA FA500 and F-201L from Daikin Industries, Ltd. Examples of commercially available aqueous dispersions of PTFE include Fluon AD-939E from Asahi ICI Fluoropolymers Co., Ltd., Fluon D-310 and D-210C from Daikin Industries, Ltd., and Teflon® 31JR from Mitsui DuPont Fluorochemicals Co., Ltd.

[0104] To improve the dispersibility of fibril-forming PTFE in resin compositions and to obtain even better flame retardancy, mechanical properties, and flexural modulus, it is also possible to use a PTFE mixture in the form of a mixture of fibril-forming PTFE and other resins.

[0105] The proportion of PTFE to the total mass of the PTFE mixture is preferably 1% by mass or more, and more preferably 5% by mass or more. Furthermore, this proportion is preferably 60% by mass or less, and more preferably 55% by mass or less. The range of the proportion of PTFE to the total mass of the PTFE mixture is preferably 1% by mass or more and 60% by mass or less (for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60% by mass), and more preferably 5% by mass or more and 55% by mass or less. When the proportion of PTFE is within this range, good dispersibility of PTFE can be achieved.

[0106] PTFE mixtures can be obtained, for example, by (1) mixing an aqueous dispersion of PTFE with an aqueous dispersion or solution of another resin and co-precipitating to obtain a co-aggregated mixture (methods described in Japanese Patent Publication No. 60-258263, Japanese Patent Publication No. 63-154744, etc.), (2) mixing an aqueous dispersion of PTFE with dried particles of another resin (method described in Japanese Patent Publication No. 4-272957), or (3) uniformly mixing an aqueous dispersion of PTFE with a solution of another resin and simultaneously obtaining each medium from such mixture. (4) A method of removing the material (as described in Japanese Patent Publication No. 06-220210, Japanese Patent Publication No. 08-188653, etc.), (5) a method of polymerizing monomers that form other resins in an aqueous dispersion of PTFE (as described in Japanese Patent Publication No. 9-95583), or (6) a method of uniformly mixing an aqueous dispersion of PTFE and a dispersion of other resins, polymerizing vinyl monomers in the resulting mixed dispersion, and then obtaining a mixture (as described in Japanese Patent Publication No. 11-29679, etc.) can be used.

[0107] Commercially available PTFE mixtures include Mitsubishi Chemical's "Metablen A3000" and GE Specialty Chemicals' "BLENDEX B449."

[0108] The content of the fluorine-containing anti-dropping agent is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.1 parts by mass or more, as PTFE, per 100 parts by mass of the resin composition. Furthermore, the content is preferably 1 part by mass or less, more preferably 0.8 parts by mass or less, and even more preferably 0.5 parts by mass or less. The range of the content of the fluorine-containing anti-dropping agent per 100 parts by mass of the resin composition is preferably 0.01 parts by mass or more and 1 part by mass or less as PTFE (for example, 0.01, 0.02, 0.05, 0.07, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1 part by mass), and more preferably 0.1 parts by mass or more and 0.8 parts by mass or less.

[0109] In addition to the other components mentioned above, a resin composition according to one aspect of the present invention may contain additives commonly used in synthetic resins, such as crosslinking agents, antistatic agents, metal soaps, filling agents, antifogging agents, plate-out prevention agents, surface treatment agents, fluorescent agents, antifungal agents, disinfectants, foaming agents, metal deactivators, mold release agents, pigments, processing aids, etc., to the extent that they do not impair the effects of the present invention.

[0110] [Method for Producing Resin Composition] Any method can be used to produce a resin composition according to one aspect of the present invention. For example, a thermoplastic resin (A), a phosphorus-based flame retardant (B), and, if necessary, an acid-modified polyolefin resin (C) and other components such as other flame retardants or flame retardant aids are thoroughly mixed using premixing means such as a V-type blender, Henschel mixer, mechanochemical device, or extruder mixer, and if necessary, granulated using an extruder granulator or briquetting machine, and then melt-kneaded and extruded in a melt kneader.

[0111] Examples of melting and mixing machines include twin-screw extruders such as vented twin-screw extruders, Banbury mixers, mixing rolls, single-screw extruders, and multi-screw extruders with three or more shafts.

[0112] The temperature during melting and mixing is, for example, 170 to 260°C (e.g., 170, 180, 190, 200, 210, 220, 230, 240, 250, or 260°C).

[0113] As described above, the extruded resin composition is either directly cut into pellets using equipment such as a pelletizer, or cooled to form strands, and then these strands are cut into pellets using equipment such as a pelletizer.

[0114] [Flame retardant masterbatch] A flame retardant masterbatch according to one aspect of the present invention is a pellet of a resin composition according to one aspect of the present invention.

[0115] [Molded Article] A molded article according to one aspect of the present invention is made of a resin composition according to one aspect of the present invention. The shape of the molded article is not particularly limited and can take various shapes such as resin plates, sheets, films, cables, and irregularly shaped products.

[0116] The molded product is obtained by molding the resin composition described above. The molding method is not particularly limited and includes extrusion, calendering, injection molding, roll molding, compression molding, blow molding, etc. The temperature when molding the resin composition is, for example, 170 to 260°C (for example, 170, 180, 190, 200, 210, 220, 230, 240, 250 or 260°C).

[0117] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in each of the different embodiments are also included within the technical scope of the present invention.

[0118] The present invention will be described in detail below with reference to examples. However, the present invention is not limited in any way by the following examples. In the following examples, percentages are based on mass unless otherwise specified.

[0119] [Evaluation Example 1] Preparation of phosphorus-based flame retardant (B) The following phosphorus-based flame retardants 1 to 3 were prepared. (Phosphorus-based flame retardant 1) Contains 50-60% piperazine pyrophosphate, 35-45% melamine pyrophosphate, and 3-6% zinc oxide relative to the total mass of the phosphorus-based flame retardant. Thermogravimetric analysis shows that the weight retention rate at 300°C when heated at 10°C / min is 85% or more. (Phosphorus-based flame retardant 2) Contains 25-65% piperazine pyrophosphate, 35-75% melamine polyphosphate, and 0.5-2% zinc oxide relative to the total mass of the phosphorus-based flame retardant. Thermogravimetric analysis shows that the weight retention rate at 300°C when heated at 10°C / min is 90% or more. (Phosphorus-based flame retardant 3) Contains 25-55% piperazine pyrophosphate and 45-75% melamine polyphosphate relative to the total mass of the phosphorus-based flame retardant. Thermogravimetric analysis shows that the weight retention rate at 300°C when heated at 10°C / min is 90% or more.

[0120] The melamine salt and piperazine salt contained in the phosphorus-based flame retardant (B) are melamine salts and piperazine salts that can be manufactured by referring to International Publication No. 2019 / 240181 or Japanese Patent Publication No. 2020-105465.

[0121] [Evaluation Example 2] Evaluation of phosphorus-based flame retardant (B) The following evaluation tests were conducted on each phosphorus-based flame retardant (B) prepared in Evaluation Example 1.

[0122] [Analysis by Image Analysis Method] The minimum particle size, maximum particle size, and circularity of the phosphorus-based flame retardant (B) were measured by volume using an image analysis device (Malvern). Principle: Image analysis device: Morphologi 4 (Malvern) Dispersion: Airflow dispersion (high pressure 4 bar) Sample volume: 3 mm 3 Magnification (objective lens): 20x Light source: Transmitted light Analysis: (1) In the evaluation of minimum and maximum particle diameter, particles with a circularity of less than 0.6 were excluded from the analysis. (2) In the evaluation of shape (circularity), particles with a circularity of less than 0.6 or a particle diameter of less than 1 μm were excluded from the analysis. The number of measurements (n) was set to 2, and the average value was adopted.

[0123] [Analysis by Laser Scattering Method] The cumulative 10% particle size (D10), cumulative 50% particle size (D50), and cumulative 90% particle size (D90) of the volume-based particle size distribution of phosphorus-based flame retardant (B) were measured using a particle size distribution analyzer (Microtrac-Bell). Principle: Laser scattering method Analyzer: MT3300EXII (Microtrac-Bell) Dispersant: Water Dispersant: Neutral surfactant Dispersion method: Built-in ultrasonic irradiation (30W 30s) Note: Particle size was calculated assuming a refractive index of 1.81 for the sample and 1.33 for the dispersion medium (water). The number of measurements (n) was 2, and the average value was adopted.

[0124] [Analysis using a powder tester] The apparent specific gravity and angle of repose of the phosphorus-based flame retardant (B) were measured using a powder testing device (manufactured by Hosokawa Micron Corporation). Device: POWDER TESTER MODEL: PT-N Three measurements were taken, and the average value was used.

[0125] [Evaluation Results] The evaluation results are shown in Tables 1 and 2.

[0126]

[0127]

[0128] [Evaluation Example 3] Preparation of Resin Composition and Molded Article The following components were blended in the following amounts and mixed by hand blending. Then, using a φ30 mm co-screw twin-screw extruder (model name "BT-30", manufactured by Plastics Engineering Laboratory Co., Ltd., L / D = 30), the mixture was melt-kneaded under the conditions of a screw rotation speed of 250 rpm and a cylinder temperature of 200°C to obtain a resin composition X1 containing a thermoplastic resin (A), a phosphorus-based flame retardant (B), and an acid-modified polyolefin resin (C). Note that "L / D" indicates the ratio of the screw length (L) to the diameter (D).

[0129] - Thermoplastic resin (A): 58% by mass Polypropylene resin (manufactured by Nippon Polypropylene Co., Ltd., "Novatec® SA06GA", melt mass flow rate 60 g / 10 min) - Phosphorus-based flame retardant (B): 40% by mass Example 1 used flame retardant 2, Example 2 used flame retardant 3, and Comparative Example 1 used flame retardant 1. - Acid-modified polyolefin resin (C): 2% by mass α-olefin / maleic anhydride copolymer (manufactured by Mitsubishi Chemical Corporation, "Diacarna® 30M", weight-average molecular weight 7,800)

[0130] Furthermore, the resin composition X1 of Reference Example 1 was obtained by preparing the same method as in Example 1, except that the following phosphorus-based flame retardant 4 was used as the phosphorus-based flame retardant (B). (Phosphorus-based flame retardant 4) Contains 30-60% ammonium polyphosphate, 10-40% melamine cyanurate, and 10-30% piperazine pyrophosphate based on the total mass of the phosphorus-based flame retardant. In thermogravimetric analysis, the weight retention rate at 300°C when heated at 10°C / min is 90% or more.

[0131] Next, the following components were hand-blended and mixed in the following amounts. Then, the resulting mixture Y1 was injection molded using a fully electric injection molding machine "SE100DU" (Sumitomo Heavy Industries, Ltd.) under the conditions of a cylinder temperature of 180-200°C (180-190-200-200-200°C) and a mold temperature of 80°C to obtain a dumbbell test specimen according to JIS K7139-A1.

[0132] • Thermoplastic resin (A): 25% by mass Long fiber glass fiber (GF)-reinforced PP compound (manufactured by Nippon Polypropylene Co., Ltd., "Funkstar® LR24A", (GF = 40%)) • Thermoplastic resin (A): 12% by mass Polypropylene resin (manufactured by Nippon Polypropylene Co., Ltd., "Novatec® SA06GA", melt mass flow rate 60 g / 10 min) • Resin composition X1: 63% by mass

[0133] The composition of the above mixture Y1 was 63.75% by mass of thermoplastic resin (A), 25.00% by mass of phosphorus-based flame retardant (B), 1.25% by mass of acid-modified polyolefin resin (C), and 10.00% by mass of GF.

[0134] [Evaluation Example 4] Evaluation of resin compositions and molded articles The following evaluation tests were conducted on each resin composition and molded article prepared in Evaluation Example 3.

[0135] [Evaluation of powder flowability] The thermoplastic resin (A) used in the preparation of the above resin composition X1 was mixed in the following proportions: 58% by mass, phosphorus-based flame retardant (B) in proportion to 40% by mass, and acid-modified polyolefin resin (C) in proportion to 2% by mass. 500 g of the mixture was put into a powder feeder and fed at a rotation speed of 280 rpm, and the discharge rate per minute (g / min) was measured.

[0136] The feeder performance was evaluated based on the average discharge rate measured over three trials. A rate of 100 g / min or less was rated as ×, 101-199 g / min as ○, and 200 g / min or more as ◎. A higher average discharge rate indicates easier supply via a feeder.

[0137] Furthermore, the stability was evaluated by assigning a score of × (for a standard deviation of 10 or more) to 6-9 (for a score of ○) and ◎ (for a score of 5 or less) based on the standard deviation of the discharge volume measured three times. A small standard deviation of the discharge volume indicates that there is little variation in the supply from the feeder and that it is stable.

[0138] In this invention, powder flowability was evaluated using the above-mentioned feeder properties and stability as indicators.

[0139] [Evaluation Results] Table 3 shows the evaluation results of the powder fluidity of the resin composition.

[0140]

[0141] As shown in Table 3, the resin composition using flame retardant 2 or 3 was found to have good feedability, stability, and excellent powder flowability.

[0142] [Evaluation of Flame Retardancy (UL94)] The obtained molded product (1 / 16 inch test rod) was used to determine flame retardancy by a vertical combustion test in accordance with the UL94 standard. "Total burning time" is the sum of the flaming burning time during the combustion test. "Number of drips" is the number of particles (drips) that fall from the test piece during the combustion test. The "Judgment" is a grade determined by the UL94 standard, which is based on (1) the burning time of each test piece after flame contact, (2) the total burning time of the five samples, (3) the burning position reached by each test piece, (4) ignition due to drips, and (5) red-hot state after the second flame contact.

[0143] [Evaluation Results] The evaluation results for the flame retardancy of the molded product are shown in Table 4.

[0144]

[0145] As shown in Table 4, the molded articles of Examples 1 and 2 were judged to be V-0 according to the UL94 standard, indicating that they have excellent flame retardancy. On the other hand, the molded article of Reference Example 1 had low flame retardancy because the phosphorus-based flame retardant (B) contained in the molded article did not contain the aforementioned components (a) and (b), resulting in a judgment of V-2 according to the UL94 standard.

[0146] [Evaluation Example 5] Evaluation of Resin Composition Resin composition X2 was obtained by mixing the thermoplastic resin (A) used in the preparation of resin composition X1 in Evaluation Example 3 in a ratio of 60% by mass and phosphorus-based flame retardant (B) in a ratio of 40% by mass. 500 g of resin composition X2 was put into a powder feeder and fed at a rotation speed of 200 rpm, and the discharge rate per minute (g / min) was measured.

[0147] The feeder performance was evaluated based on the average discharge rate measured over three trials. A rate of 75 g / min or less was rated as ×, 76-149 g / min as ○, and 150 g / min or more as ◎. A higher average discharge rate indicates easier supply via a feeder.

[0148] Furthermore, the stability was evaluated by assigning a rating of × if the standard deviation of the discharge volume measured three times was 5 or higher, ○ if it was 3 to 4, and ◎ if it was 2 or lower. A small standard deviation of the discharge volume indicates that there is little variation in the supply from the feeder and that it is stable.

[0149] In the present invention, powder flowability was evaluated using the feeder properties and stability described above as indicators, similar to Evaluation Example 4.

[0150] [Evaluation Results] Table 5 shows the evaluation results for the powder fluidity of resin composition X2.

[0151]

[0152] As shown in Table 5, the resin composition containing a thermoplastic resin (A) and flame retardant 2 or 3 as a phosphorus-based flame retardant (B) was found to have good feedability as well as stability, and to possess excellent powder flowability.

[0153] A resin composition according to one aspect of the present invention can be used as a material for molded articles with excellent flame retardancy.

Claims

1. A resin composition comprising a thermoplastic resin (A) and a phosphorus-based flame retardant (B), wherein the cumulative 50% particle size (D50) in the volume-based particle size distribution of the phosphorus-based flame retardant (B) is 11 μm or more, and the cumulative 90% particle size (D90) in the volume-based particle size distribution of the phosphorus-based flame retardant (B) is 20 μm or more, and the phosphorus-based flame retardant (B) contains component (a) and component (b), wherein component (a) is at least one melamine salt selected from the group consisting of melamine orthophosphate, melamine pyrophosphate and melamine polyphosphate, and component (b) is at least one piperazine salt selected from the group consisting of piperazine orthophosphate, piperazine pyrophosphate and piperazine polyphosphate.

2. The resin composition according to claim 1, wherein the angle of repose of the phosphorus-based flame retardant (B) is 52° or less.

3. The resin composition according to claim 1, wherein the circularity of the phosphorus-based flame retardant (B), obtained by volume-based particle size distribution measurement, is 0.92 or greater.

4. The resin composition according to claim 1, wherein component (a) contains melamine polyphosphate.

5. The resin composition according to claim 1, wherein component (b) comprises piperazine pyrophosphate.

6. The resin composition according to claim 1, wherein component (a) contains melamine polyphosphate and component (b) contains piperazine pyrophosphate.

7. The resin composition according to claim 6, comprising 35% to 75% by mass of melamine polyphosphate and 25% to 65% by mass of piperazine pyrophosphate, based on the total mass of the phosphorus-based flame retardant (B).

8. The resin composition according to claim 1, wherein the thermoplastic resin (A) comprises a polyolefin resin.

9. The resin composition according to claim 8, wherein the polyolefin resin is mainly composed of polypropylene.

10. The resin composition according to claim 1, further comprising an acid-modified polyolefin resin (C).

11. The resin composition according to claim 10, wherein the acid-modified polyolefin resin (C) comprises a copolymer of an α-olefin and an unsaturated carboxylic acid.

12. A flame retardant masterbatch, which is a pellet of the resin composition according to any one of claims 1 to 11.

13. A molded article comprising the resin composition according to any one of claims 1 to 11.

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