Resin compositions, pellets, and molded articles

Abstract

The present invention provides a resin composition exhibiting excellent flame retardancy after treatment in a humid heat environment and impact resistance in low-temperature environments, as well as pellets and molded articles using the resin composition. [Solution] The resin composition according to this disclosure comprises 100 parts by mass of polycarbonate resin (A), 0.01 to 0.3 parts by mass of a metal salt flame retardant (B), and 2.5 to 10 parts by mass of inorganic particles (C) having an average particle diameter of 0.01 to 0.4 μm.

Description

[Technical Field]

[0001] This invention relates to resin compositions, pellets, and molded articles. In particular, it relates to resin compositions having polycarbonate resin as a main component. [Background technology]

[0002] Polycarbonate resin is a resin with excellent heat resistance, impact resistance, flame retardancy, and transparency, and is used in a wide range of fields, including automotive materials, electrical materials, and housing materials. In particular, flame-retardant polycarbonate resin compositions are widely used as components in various office automation (OA) information equipment such as computers, notebook PCs, photocopiers, printers, and portable devices.

[0003] Conventionally, methods using brominated or phosphorus-based flame retardants have been widely employed in the production of flame-retardant polycarbonate resin compositions. However, conventional methods have the problem of requiring large amounts of flame retardants, which tend to degrade various physical properties of the resin composition. Furthermore, due to environmental concerns, there is a strong demand for flame-retardant aromatic polycarbonate resin compositions that do not use brominated or phosphorus-based flame retardants.

[0004] On the other hand, the use of metal salt flame retardants is also being considered as a method for flame retarding polycarbonate resins without using brominated or phosphorus-based flame retardants, and improved technologies have been reported in recent years (Patent Document 1, etc.). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2004-002750 [Overview of the project] [Problems that the invention aims to solve]

[0006] Therefore, there is a need for flame-retardant polycarbonate resin compositions using metal salt flame retardants that can maintain high performance under a wide range of usage conditions and environments. Specifically, there is a need for a resin composition that exhibits excellent flame retardancy after treatment in a humid heat environment and superior impact resistance in low-temperature environments. The present invention aims to solve these problems and to provide a resin composition that exhibits excellent flame retardancy after treatment in a humid heat environment and impact resistance in a low-temperature environment, as well as pellets and molded articles using the resin composition. [Means for solving the problem]

[0007] Under these circumstances, the inventors conducted research and found that the above problems can be solved by blending inorganic particles with an average particle size of 0.01 to 0.4 μm together with a metal salt flame retardant in a polycarbonate resin. Specifically, the above problem was solved by the following means. [1] A resin composition comprising 100 parts by mass of polycarbonate resin (A), 0.01 to 0.3 parts by mass of a metal salt flame retardant (B), and 2.5 to 10 parts by mass of inorganic particles (C) having an average particle size of 0.01 to 0.4 μm. [2] The resin composition according to [1], wherein the inorganic particles (C) contain silica. [3] The resin composition according to [1] or [2], wherein the inorganic particles (C) are surface-treated with a surface treatment agent. [4] The resin composition according to any one of [1] to [3], further comprising more than 0 parts by mass and 1 part by mass or less of a droop prevention agent (D) per 100 parts by mass of the polycarbonate resin (A). [5] The resin composition according to any one of [1] to [4], wherein the elastomer content is less than 1 part by mass per 100 parts by mass of the polycarbonate resin (A). [6] The inorganic particles (C) contain silica, The inorganic particles (C) are surface-treated with a surface treatment agent. Furthermore, the polycarbonate resin (A) contains more than 0 parts by mass and 1 part by mass or less of a drip-preventing agent (D) per 100 parts by mass. The resin composition according to any one of [1] to [5], wherein the elastomer content is less than 1 part by mass per 100 parts by mass of the polycarbonate resin (A). A pellet of the resin composition described in any one of [7][1] to [6]. A molded article formed from any one of the resin compositions described in [8], [1], to [6]. A molded product formed from the pellets described in [9] and [7]. [Effects of the Invention]

[0008] The present invention makes it possible to provide a resin composition with excellent flame retardancy after treatment in a humid heat environment and impact resistance in a low-temperature environment, as well as pellets and molded articles using the resin composition. [Modes for carrying out the invention]

[0009] The following describes in detail embodiments for carrying out the present invention (hereinafter simply referred to as "this embodiment"). Note that the following embodiment is illustrative for explaining the present invention, and the present invention is not limited to this embodiment. In this specification, "~" is used to mean that the numerical values ​​before and after it are included as the lower and upper limits. Furthermore, the upper and lower limits of the numerical values ​​in this specification are given as examples of this embodiment, regardless of the combination of upper and lower limits. In this specification, a preferred combination of embodiments is a more preferred embodiment. In this specification, all physical properties and characteristic values ​​shall be those at 23°C unless otherwise specified.

[0010] In this specification, the glass transition temperature (Tg, sometimes referred to as the glass transition point) shall be the value measured according to differential scanning calorimetry (DSC) in accordance with ISO 11357, unless otherwise specified. If the measurement methods, etc., described in the standards shown in this specification differ from year to year, unless otherwise specified, the standards as of January 1, 2024 shall apply. If the measurement methods, etc., described in the standards shown in this specification have been discontinued as of January 1, 2024, the standards in effect at the time of discontinuation shall apply.

[0011] The resin composition of this embodiment is characterized by containing 0.01 to 0.3 parts by mass of a metal salt flame retardant (B) and 2.5 to 10 parts by mass of inorganic particles (C) (in this specification, sometimes simply referred to as "inorganic particles (C)") having an average particle size of 0.01 to 0.4 μm, per 100 parts by mass of polycarbonate resin (A). This configuration makes it possible to provide a resin composition with excellent flame retardancy after treatment in a humid heat environment and impact resistance in a low-temperature environment. Furthermore, it is possible to provide a resin composition with excellent impact resistance after humid heat treatment. Polycarbonate resin is inherently a resin with excellent impact resistance, but its impact resistance at low temperatures is not sufficient. Therefore, conventionally, elastomers have been added to improve impact resistance at low temperatures. However, the inventors' research revealed that if the amount of elastomer added is too small, sufficient impact resistance at low temperatures cannot be achieved, while if the amount of elastomer added is too large, flame retardancy is impaired. Under these circumstances, in this embodiment, we found that the above problems can be solved by incorporating inorganic particles with a small particle size. In other words, it is presumed that when a molded product obtained by compounding small-particle-sized inorganic particles with polycarbonate resin is subjected to impact stress, the inorganic particles inhibit the straight propagation of stress, dispersing it in other directions. Since this function works regardless of temperature, it is presumed that impact resistance at low temperatures can also be improved. On the other hand, elastomers are organic components, and molded articles obtained by compounding elastomers with polycarbonate resin tend to have poor flame retardancy. In particular, the inventors' research revealed that flame retardancy tends to be poor after moist heat treatment. In contrast, when inorganic particles are compounded with polycarbonate resin, the impact on flame retardancy tends to be small. By configuring the present embodiment as described above, it becomes possible to provide a resin composition that is excellent in flame retardancy after being treated in a humid heat environment and impact resistance in a low-temperature environment. Furthermore, it becomes possible to provide a resin composition that is also excellent in impact resistance after being subjected to a humid heat treatment.

[0012] Hereinafter, embodiments of the present invention will be described in detail. However, the description of the constituent elements described below is an example of an embodiment of the present invention and is not limited to these contents.

[0013] <Polycarbonate resin (A)> The resin composition of the present embodiment contains a polycarbonate resin (A). Specifically, the polycarbonate resin (A) is not particularly limited as long as it contains a -[O-R-OC(=O)]- unit (where R is an organic group, preferably a hydrocarbon group, more preferably an aliphatic group, an aromatic group, or a group containing both an aliphatic group and an aromatic group, and further having a linear or branched structure) containing a carbonate ester bond in the main chain of the molecule. In the present embodiment, the polycarbonate resin (A) is preferably an aromatic polycarbonate resin, and more preferably a polycarbonate resin having a bisphenol skeleton. By using such a polycarbonate resin, more excellent heat resistance and toughness are achieved. In the present embodiment, for the polycarbonate resin having a bisphenol skeleton, it is preferable that 90 mol% or more of all the constituent units are constituent units having a bisphenol skeleton, more preferably 90 mol% or more of all the constituent units are constituent units derived from at least one of bisphenol A, bisphenol C, and bisphenol AP, and even more preferably 90 mol% or more of all the constituent units are constituent units derived from bisphenol A.

[0014] Furthermore, the viscosity-average molecular weight (Mv) of the polycarbonate resin (A) is preferably 10,000 or more, more preferably 12,000 or more, and even more preferably 15,000 or more. Setting it above the lower limit tends to further improve the durability of the resulting molded product. The upper limit of the viscosity-average molecular weight (Mv) of the polycarbonate resin (A) is preferably 50,000 or less, more preferably 40,000 or less, and even more preferably 30,000 or less. Setting it below the upper limit tends to further improve the moldability of the molded product. The viscosity-average molecular weight (Mv) is calculated using methylene chloride as the solvent, determining the intrinsic viscosity [η] (unit: dL / g) at 25°C using an Ubbelohde viscometer, and then using Schnell's viscosity formula, i.e., η = 1.23 × 10⁻⁶ -4 ×Mv 0.83 It means a value calculated from ,. When using two or more types of polycarbonate resin, the viscosity-average molecular weight of the mixture shall be used.

[0015] The method for producing polycarbonate resin (A) is not particularly limited, and conventionally known methods such as the phosgene method (interfacial polymerization) or the melting method (transesterification) can be used. Furthermore, when using the melting method, polycarbonate resin with adjusted amounts of OH groups at the end groups can be used.

[0016] The polycarbonate resin (A) used in this embodiment may be recycled polycarbonate resin. In this embodiment, even when using recycled polycarbonate resin, excellent performance equivalent to that of virgin polycarbonate resin can be achieved. Recycled polycarbonate resin refers to virgin polycarbonate resin that has undergone some kind of molding or processing. This includes not only products returned from the market, but also defective polycarbonate resin molded products and scraps from the manufacturing of polycarbonate resin molded products. Molded products include injection molded products, extruded products, and other molded products. Examples of recycled polycarbonate resin include that obtained through material recycling, where collected used polycarbonate resin molded products are crushed, alkaline-washed, and reused as fibers, as well as that obtained through chemical recycling (chemical decomposition method) and mechanical recycling. Chemical recycling involves chemically decomposing collected used polycarbonate resin molded products to return them to their raw material level and then resynthesizing the polycarbonate resin. Mechanical recycling, on the other hand, is a method that makes it possible to remove dirt from polycarbonate resin molded products more reliably than material recycling by performing alkaline cleaning more rigorously than in the aforementioned material recycling, or by vacuum drying at high temperatures. For example, recycled polycarbonate resin can be obtained from used polycarbonate resin molded products by removing foreign matter, crushing and washing them, and then pelletizing them using an extruder. Examples of used polycarbonate resin molded products include discs, sheets (including films), meter covers, headlamp lenses, and bottles.

[0017] For further details regarding the polycarbonate resin (A), please refer to paragraphs 0013-0041 of Japanese Patent Publication No. 2021-084942, paragraphs 0040-0073 of Japanese Patent Publication No. 2019-035001, paragraphs 0016-0043 of Japanese Patent Publication No. 2018-103518, paragraphs 0011-0048 of International Publication No. 2021 / 090823, and paragraphs 0011-0043 of Japanese Patent Publication No. 2019-156942, in addition to the above, and these contents are incorporated herein by reference.

[0018] The proportion of polycarbonate resin (A) in the resin composition of this embodiment is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 97% by mass or more. Setting it above the lower limit tends to further improve the impact resistance of the resulting molded product. Furthermore, the proportion of polycarbonate resin (A) in the resin composition of this embodiment is preferably 99% by mass or less. The resin composition of this embodiment may contain only one type of polycarbonate resin (A), or it may contain two or more types. When two or more types of polycarbonate resin (A) are included, it is preferable that the total amount is within the above range.

[0019] <Metal salt flame retardant (B)> The resin composition of this embodiment contains a metal salt flame retardant (B). By including the metal salt flame retardant, a molded product with excellent flame retardancy can be obtained. The metal salt flame retardant (B) is preferably an alkali metal salt of an organic acid and / or an alkaline earth metal salt of an organic acid, and more preferably an alkali metal salt of an organic acid. Examples of metal salt flame retardants (B) include metal sulfonic acid salts, metal carboxylate salts, metal borate salts, metal phosphate salts, and metal sulfonamide salts. From the viewpoint of thermal stability, metal sulfonic acid salts and metal sulfonamide salts are preferred, metal sulfonic acid salts are more preferred, and alkali metal sulfonic acid salts are even more preferred.

[0020] Examples of alkali metals that make up alkali metal salts include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs). Among these, sodium, potassium, and cesium are preferred, sodium and potassium are more preferred, and potassium is even more preferred.

[0021] Examples of preferred alkali metal sulfonic acid salts include alkali metal salts of fluorine-containing aliphatic sulfonic acids and / or aromatic sulfonic acids. Specific examples of preferred alkali metal salts of fluorine-containing aliphatic sulfonic acids having at least one CF bond in the molecule, such as potassium perfluorobutanesulfonate (potassium nonafluorobutanesulfonate), lithium perfluorobutanesulfonate, sodium perfluorobutanesulfonate, cesium perfluorobutanesulfonate, potassium trifluoromethanesulfonate, lithium trifluoromethanesulfonate, sodium trifluoromethanesulfonate, and cesium trifluoromethanesulfonate; dipotassium diphenylsulfon-3,3'-disulfonate, potassium diphenylsulfon-3,3'-disulfonate, sodium benzenesulfonate, and (poly)st Examples include alkali metal salts of aromatic sulfonic acids having at least one aromatic group in their molecule, such as sodium benzenesulfonate, sodium p-toluenesulfonate, sodium (branched) dodecylbenzenesulfonate, sodium trichlorobenzenesulfonate, potassium benzenesulfonate, potassium styrenesulfonate, potassium (poly)styrenesulfonate, potassium p-toluenesulfonate, potassium (branched) dodecylbenzenesulfonate, potassium trichlorobenzenesulfonate, cesium benzenesulfonate, cesium (poly)styrenesulfonate, cesium p-toluenesulfonate, cesium (branched) dodecylbenzenesulfonate, and cesium trichlorobenzenesulfonate. Potassium sulfonate is particularly preferred as the alkali metal sulfonate salt.

[0022] Examples of preferred alkali metal sulfonamide salts include lithium bisfluorosulfonylimide, lithium bistrifluoromethylsulfonylimide, lithium bispentafluoroethylsulfonylimide, lithium bisheptafluoropropylsulfonylimide, lithium bisnonanefluorobutylsulfonylimide, sodium bisfluorosulfonylimide, sodium bistrifluoromethylsulfonylimide, sodium bispentafluoroethylsulfonylimide, sodium bisheptafluoropropylsulfonylimide, sodium bisnonanefluorobutylsulfonylimide, potassium bisfluorosulfonylimide, potassium bistrifluoromethylsulfonylimide, potassium bispentafluoroethylsulfonylimide, potassium bisheptafluoropropylsulfonylimide, and potassium bisnonanefluorobutylsulfonylimide.

[0023] For other examples of alkali metal sulfonates, refer to paragraphs 0069 to 0078 of Japanese Patent Publication No. 2015-117298, which are incorporated herein by reference.

[0024] The content of the metal salt flame retardant (B) in the resin composition of this embodiment is 0.01 parts by mass or more, preferably 0.03 parts by mass or more, more preferably 0.04 parts by mass or more, even more preferably 0.05 parts by mass or more, and even more preferably 0.06 parts by mass or more, per 100 parts by mass of (A) polycarbonate resin. Setting it above the lower limit promotes the formation of a carbonized layer during combustion of the polycarbonate resin, thereby further enhancing flame retardancy. Furthermore, the content of the metal salt flame retardant (B) is 0.3 parts by mass or less, preferably 0.25 parts by mass or less, more preferably 0.2 parts by mass or less, even more preferably 0.15 parts by mass or less, even more preferably 0.12 parts by mass or less, and even more preferably 0.1 parts by mass or less, per 100 parts by mass of (A) polycarbonate resin. Setting it below the upper limit tends to result in a more effective flame retardant effect despite a reduced content of the metal salt flame retardant (B). The resin composition of this embodiment may contain only one type of metal salt flame retardant (B), or it may contain two or more types. When two or more types of metal salt flame retardants (B) are included, it is preferable that the total amount is within the above range.

[0025] The resin composition of this embodiment may or may not contain flame retardants other than the metal salt flame retardant (B). Examples of flame retardants other than the metal salt flame retardant (B) include phosphorus-based flame retardants and halogen-based flame retardants. An example of the resin composition of this embodiment is one that is substantially free of flame retardants other than the metal salt flame retardant (B). Substantially free means that the content of flame retardants other than the metal salt flame retardant (B) in the resin composition is less than 10% by mass of the content of the metal salt flame retardant (B), preferably less than 5% by mass, more preferably less than 3% by mass, and even more preferably less than 1% by mass.

[0026] <Inorganic particles (C) with an average particle size of 0.01 to 0.4 μm> The resin composition of this embodiment contains inorganic particles (C) having an average particle size of 0.01 to 0.4 μm. By including inorganic particles (C), molded articles with excellent impact resistance, particularly at low temperatures and after moist heat treatment, can be obtained. This is especially preferable because it allows for the maintenance of these impact resistance properties while maintaining flame retardancy.

[0027] The inorganic particles (C) used in this embodiment have an average particle diameter of 0.4 μm or less, preferably 0.35 μm or less, more preferably 0.3 μm or less, even more preferably 0.25 μm or less, even more preferably 0.2 μm or less, and even more preferably 0.15 μm or less. By keeping the average particle diameter below the above upper limit, a molded product with high impact resistance in low-temperature environments can be obtained. Furthermore, flame retardancy tends to improve as well. The lower limit of the average particle diameter of the inorganic particles (C) is 0.01 μm or more, and may be 0.03 μm or more, 0.05 μm or more, 0.08 μm or more, or 0.1 μm or more, depending on the application. The average particle diameter of inorganic particles (C) is defined as the median diameter (D50).

[0028] The type of inorganic particles (C) is not specifically defined, but examples include silica, zirconia, barium sulfate, calcium carbonate, and alumina, with silica being preferred. Silica is generally produced by gas-phase, sol-gel, or precipitation methods. For use in this invention, silica obtained by the sol-gel method is preferred, as it tends to yield silica with relatively uniform particle size and minimal particle fusion.

[0029] In this embodiment, it is preferable that the inorganic particles (C) used are surface-treated. Surface treatment with a surface treatment agent reduces the amount of hydroxyl groups present on the surface of the inorganic particles (C), or the presence of the surface treatment agent on the surface makes it difficult for hydroxyl groups to be exposed on the surface, thus hydrophobicizing the surface of the inorganic particles (C) and making it difficult for the inorganic particles (C) to absorb water. The metal salt flame retardant (B) achieves flame retardancy by forming a carbonized layer on the molded product, but when the inorganic particles (C) become less able to absorb water, the carbonized layer is more easily formed, and flame retardancy tends to improve further. Examples of surface treatment agents for inorganic particles (C) include urethane-based surface treatment agents, epoxy-based surface treatment agents, and silane coupling agents. In this embodiment, it is preferable that the inorganic particles (C) are silica that has undergone surface treatment.

[0030] The inorganic particle (C) content in the resin composition of this embodiment is 2.5 parts by mass or more, preferably 3 parts by mass or more, more preferably 3.5 parts by mass or more, even more preferably 4 parts by mass or more, even more preferably 4.5 parts by mass or more, and also 10 parts by mass or less, preferably 9 parts by mass or less, more preferably 8 parts by mass or less, even more preferably 7 parts by mass or less, even more preferably 6 parts by mass or less, and even more preferably 5.5 parts by mass or less. Setting the content above the lower limit tends to further improve impact resistance at low temperatures, impact resistance after moist heat treatment, and flammability. Conversely, exceeding the upper limit tends to impair impact resistance because the particle dispersion becomes insufficient and the apparent particle size increases. The resin composition of this embodiment may contain only one type of inorganic particle (C) or two or more types. When two or more types of inorganic particles (C) are included, it is preferable that the total amount is within the above range.

[0031] The resin composition of this embodiment may or may not contain inorganic particles other than inorganic particles (C) having an average particle diameter of 0.01 to 0.4 μm. In particular, it is preferable that the resin composition of this embodiment substantially does not contain inorganic particles with an average particle diameter greater than 0.4 μm. "Substantially contained" means that the content of inorganic particles with an average particle diameter of more than 0.4 μm in the resin composition is less than 15% by mass of the content of inorganic particles (C) with an average particle diameter of 0.01 to 0.4 μm in the resin composition, preferably less than 10% by mass, more preferably less than 7% by mass, even more preferably less than 5% by mass, even more preferably less than 3% by mass, and may be less than 1% by mass.

[0032] <Drip prevention agent (D)> The resin composition of this embodiment may also contain a sagging prevention agent (D). The drip-preventing agent (D), also known as the anti-dripping agent, is preferably a fluoropolymer having fibril-forming ability. Such fluoropolymers having fibril-forming ability readily disperse in the resin composition and tend to bond with each other to form a fibrous structure. Fluoropolymers having fibril-forming ability preferably have an extremely high molecular weight of 1 million to 10 million, and tend to bond with each other to form fibers when subjected to external forces such as shear force. Preferred fluoropolymers include tetrafluoroethylene (TFE) resin, perfluoroalkoxy (PFA) resin, and fluoroethylene propylene (FEP) resin, with polytetrafluoroethylene being particularly preferred.

[0033] Examples of fluoropolymers that have fibril-forming ability include Teflon® 6J manufactured by Mitsui DuPont Fluorochemicals, Polyflon manufactured by Daikin Industries, Ltd., and Metabren A-3800 manufactured by Mitsubishi Chemical Corporation.

[0034] It is also preferable to use the fluoropolymer in the form of an aqueous dispersion. This dispersion is an aqueous dispersion prepared by adding a surfactant to a fluoropolymer latex, which is usually obtained by emulsion polymerization, and then concentrating and stabilizing it. The fluoropolymer content in the aqueous dispersion is preferably 20 to 80% by mass, and particularly preferably 30 to 70% by mass. Examples of aqueous dispersions of polytetrafluoroethylene include Teflon® 30J manufactured by Mitsui DuPont Fluorochemicals and Fluon D-1 manufactured by Daikin Industries.

[0035] Furthermore, the fluoropolymer having fibril-forming ability preferably has a primary particle diameter in the range of 0.05 to 1.0 μm, and more preferably 0.1 to 0.5 μm. In the resin composition, the fluoropolymer mainly takes the form of fibrils with a thickness of 0.5 μm or less, and it is preferable that the fibrils exist in a network structure and / or a branched structure.

[0036] If the resin composition of this embodiment contains a drip-preventing agent (D), its content is preferably more than 0 parts by mass, more preferably 0.01 parts by mass or more, more preferably 0.03 parts by mass or more, even more preferably 0.05 parts by mass or more, even more preferably 0.07 parts by mass or more, even more preferably 0.1 parts by mass or more, and even more preferably 0.2 parts by mass or more, per 100 parts by mass of (A) polycarbonate resin. Setting the content above the lower limit tends to effectively exhibit a drip-preventing effect. Furthermore, the content of the drip-preventing agent (D) is preferably 1 part by mass or less, more preferably 0.7 parts by mass or less, and even more preferably 0.5 parts by mass or less, per 100 parts by mass of (A) polycarbonate resin. Setting the content below the upper limit tends to improve the mechanical strength of the resulting molded product and also improve its appearance. The resin composition of this embodiment may contain only one type of anti-sagging agent (D), or it may contain two or more types. When two or more types of anti-sagging agents (D) are included, it is preferable that the total amount is within the above range.

[0037] <Stabilizer (E)> The resin composition of this embodiment may also contain a stabilizer (E). Examples of stabilizers (E) include heat stabilizers and antioxidants. Examples of stabilizers (E) include phenolic, amine, phosphorus, and thioether-based stabilizers. In this embodiment, phosphorus-based heat stabilizers and / or phenolic antioxidants are preferred.

[0038] Any known phosphorus-based heat stabilizer can be used. Specific examples include phosphorus oxoacids such as phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, and polyphosphate; acidic pyrophosphate metal salts such as sodium acidic pyrophosphate, potassium acidic pyrophosphate, and calcium acidic pyrophosphate; phosphates of Group 1 or Group 2B metals such as potassium phosphate, sodium phosphate, cesium phosphate, and zinc phosphate; and organic phosphate compounds, organic phosphite compounds, and organic phosphonite compounds, with organic phosphite compounds being particularly preferred.

[0039] Examples of organic phosphite compounds include triphenyl phosphite, tris(mononylphenyl) phosphite, tris(mononyl / dinonylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, monooctyldiphenyl phosphite, dioctylmonophenyl phosphite, monodecyldiphenyl phosphite, didecylmonophenyl phosphite, tridecyl phosphite, trilauryl phosphite, tristearyl phosphite, and 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite. Examples of such organic phosphite compounds include, for example, "ADEKA Stab (registered trademark; hereinafter the same) 1178," "ADEKA Stab 2112," and "ADEKA Stab HP-10" manufactured by ADEKA Corporation, "JP-351," "JP-360," and "JP-3CP" manufactured by Johoku Chemical Industry Co., Ltd., and "Irgaphos (registered trademark) 168" manufactured by BASF.

[0040] As a phenolic antioxidant, a hindered phenolic antioxidant is preferably used. Specific examples of hindered phenol antioxidants include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], 2,4-dimethyl-6-(1-methylpentadecyl)phenol, diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphate, 4,6-bis(octyl) Examples include ruthiomethyl)-o-cresol, ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazine-2-ylamino)phenol, and 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate.

[0041] Among these, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate are preferred. Specific examples of such hindered phenol antioxidants include, for example, BASF's "Irganox (registered trademark; hereinafter the same) 1010" and "Irganox 1076," and ADEKA's "ADEKA Stab AO-50" and "ADEKA Stab AO-60."

[0042] The content of stabilizer (E) in the resin composition of this embodiment is usually 0.001 parts by mass or more, preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, and usually 1 part by mass or less, preferably 0.5 parts by mass or less, more preferably 0.3 parts by mass or less, per 100 parts by mass of polycarbonate resin (A). By setting the content of stabilizer (E) within the above range, the effect of adding the stabilizer is more effectively exhibited. The resin composition of this embodiment may contain only one type of stabilizer (E) or two or more types. When two or more types of stabilizer (E) are included, it is preferable that the total amount is within the above range.

[0043] <Release agent (F)> The resin composition of this embodiment may contain a mold release agent (F). Examples of the release agent (F) include aliphatic carboxylic acids, salts of aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds with a number average molecular weight of 200 to 15,000, polysiloxane-based silicone oils, ketone waxes, and light amides. Aliphatic carboxylic acids, salts of aliphatic carboxylic acids, and esters of aliphatic carboxylic acids and alcohols are preferred, and esters of aliphatic carboxylic acids and alcohols are more preferred.

[0044] Examples of esters of aliphatic carboxylic acids and alcohols include saturated or unsaturated monovalent or divalent aliphatic carboxylic acid esters, fatty acid esters such as glycerol fatty acid esters and sorbitan fatty acid esters, and their partially saponified products. Among these, fatty acid monoesters and fatty acid diesters composed of fatty acids having 11 to 28 carbon atoms, more preferably 17 to 21 carbon atoms, and alcohols are preferred.

[0045] Examples of fatty acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, melissic acid, tetrariacontanoic acid, montanic acid, adipic acid, and azelaic acid. Furthermore, fatty acids may also be alicyclic. Examples of alcohols include saturated or unsaturated monohydric or polyhydric alcohols. These alcohols may have substituents such as fluorine atoms or aryl groups. Among these, monohydric or polyhydric saturated alcohols with 30 or fewer carbon atoms are preferred, and aliphatic saturated monohydric or polyhydric alcohols with 30 or fewer carbon atoms are more preferred. Here, "aliphatic" includes alicyclic compounds. Specific examples of such alcohols include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, and dipentaerythritol. The above-mentioned ester compounds may contain aliphatic carboxylic acids and / or alcohols as impurities, and may also be mixtures of multiple compounds.

[0046] Specific examples of fatty acid esters include glycerin monostearate, glycerin monobehenate, glycerin dibehenate, glycerin-12-hydroxymonostearate, sorbitan monobehenate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tetrastearate, stearyl stearate, and ethylene glycol montanate. Details of the release agent (F) can be found in paragraphs 0055 to 0060 of Japanese Patent Publication No. 2018-095706 and paragraphs 0106 to 0115 of Japanese Patent Publication No. 2015-117298, in addition to the above, and this information is incorporated herein by reference.

[0047] If the resin composition of this embodiment contains a release agent (F), its content is preferably 0.05 to 3% by mass, more preferably 0.1 to 0.8% by mass, and even more preferably 0.1 to 0.6% by mass. The resin composition of this embodiment may contain only one type of release agent (F) or two or more types. When two or more types of release agents (F) are included, it is preferable that the total amount is within the above range.

[0048] <Other ingredients> The resin composition of this embodiment may further contain other components not listed above. Examples of other components include reinforcing agents, colorants, flame retardants other than metal salt flame retardants, flame retardant additives, ultraviolet absorbers, fluorescent whitening agents, impact resistance modifiers, epoxy compounds, antifogging agents, flow modifiers, plasticizers, dispersants, antibacterial agents, antiviral agents, and the like. Details of these components can be found in paragraphs 0107-0115 of Japanese Patent Application Publication No. 2014-136710, paragraphs 0107-0128 of Japanese Patent Application Publication No. 2015-117298, paragraphs 0055-0061 of Japanese Patent Application Publication No. 2018-095706, and paragraphs 0047-0103 of International Publication No. 2021 / 241471, the contents of which are incorporated herein by reference. The content of the other components mentioned above, if present, is, for example, 0.001% by mass or more, and for example, less than 5.0% by mass, preferably less than 3.0% by mass, and more preferably less than 1.0% by mass, based on the mass of the resin composition. In this embodiment, the resin composition preferably contains a total of 95% by mass or more of the polycarbonate resin (A), metal salt flame retardant (B), and inorganic particles (C), and more preferably 97% by mass or more. Furthermore, it is preferable that the total of the polycarbonate resin (A), metal salt flame retardant (B), inorganic particles (C), stabilizer (E), and mold release agent (F) accounts for 97% by mass or more of the resin composition, and more preferably 99% by mass or more.

[0049] The resin composition of this embodiment may or may not contain an elastomer. As for the elastomer, a copolymer obtained by graft copolymerizing a rubber component with a monomer component that can copolymerize with it is preferred. The elastomer content in the resin composition of this embodiment is preferably less than 2 parts by mass, more preferably less than 1 part by mass, even more preferably less than 0.7 parts by mass, even more preferably less than 0.5 parts by mass, even more preferably less than 0.3 parts by mass, and may be less than 0.1 parts by mass, per 100 parts by mass of polycarbonate resin (A). By keeping it below the above upper limit, the effects of the present invention tend to be exhibited more effectively.

[0050] The resin composition of this embodiment is also suitable for resin compositions containing colorants. In other words, the resin composition of this embodiment can be made to have excellent flame retardancy after treatment in a humid heat environment and impact resistance in a low-temperature environment, even when a black coloring agent (e.g., carbon black), a red coloring agent, or a white coloring agent (e.g., titanium dioxide) is added in addition to the natural color. In particular, in resin compositions containing elastomers, the inclusion of colorants tended to result in inferior flame retardancy after treatment in a humid heat environment. However, the resin composition of this embodiment can be made to have excellent flame retardancy after treatment in a humid heat environment and impact resistance in low-temperature environments, even when colorants are included.

[0051] <Physical properties of resin compositions> The resin composition of this embodiment can provide molded articles with excellent impact resistance. Specifically, using the aforementioned resin composition, an ISO test specimen with a thickness of 3 mm was molded, and the notched Charpy impact strength at 23°C, measured according to ISO 179-1, was 50 kJ / m². 2 Preferably, it is 55 kJ / m 2 It is more preferable that it be greater than or equal to 60kJ / m³ 2 It is even more preferable that the above is true. There is no upper limit to the notched Charpy impact strength, but it is 90 kJ / m 2 The following is practical. Furthermore, the resin composition of the present embodiment can provide a molded product with excellent impact resistance at low temperatures. Specifically, using the resin composition, an ISO test piece with a thickness of 3 mm is molded, and the notch Charpy impact strength at -40°C measured based on ISO179-1 is 30 kJ / m 2 or more, preferably 37 kJ / m 2 or more, more preferably 40 kJ / m 2 or more, still more preferably 45 kJ / m 2 or more, even more preferably. The upper limit of the notch Charpy impact strength is not particularly defined, but 80 kJ / m 2 or less is practical. In addition, the resin composition of the present embodiment can increase the retention rate of impact resistance after wet heat environment treatment. Specifically, using the resin composition, an ISO test piece with a thickness of 3 mm is molded, and the retention rate of the notch Charpy impact strength ((notch Charpy impact strength at 23°C after immersion in hot water / notch Charpy impact strength at 23°C before immersion in hot water) × 100, unit: %) of the ISO test piece after being immersed in hot water at 82°C for 168 hours with respect to the notch Charpy impact strength at 23°C measured based on ISO179-1 is preferably 70% or more, more preferably 80% or more, still more preferably 85% or more, even more preferably 90% or more, and even more preferably 91% or more. The upper limit of the retention rate of the notch Charpy impact strength at 23°C after immersion in hot water is 100%, and even 99% or less can sufficiently meet the required performance.

[0052] In addition, the resin composition of the present embodiment can be made to have excellent flame retardancy after wet heat environment treatment. Specifically, the resin composition of this embodiment is molded into a UL test specimen measuring 125 mm in length, 13 mm in width, and 1.5 mm in thickness, and after immersion in hot water at 82°C for 168 hours, the total flame burning time measured in accordance with the UL-94 test is preferably 125 seconds or less, more preferably 100 seconds or less, even more preferably 50 seconds or less, even more preferably 30 seconds or less, even more preferably 20 seconds or less, even more preferably 15 seconds or less, and especially most preferably 10 seconds or less. The lower limit of the total flame burning time is preferably 0 seconds, and 1 second or more is practical.

[0053] <Manufacturing of resin compositions> There are no limitations on the manufacturing method of the resin composition of this embodiment, and a wide range of known methods for manufacturing resin compositions can be used. For example, a method may be used in which polycarbonate resin (A), metal salt flame retardant (B), inorganic particles (C), and other components that may be added as needed are pre-mixed using various mixers such as a tumbler or Henschel mixer, and then melt-kneaded using a mixer such as a Banbury mixer, roll, brabender, single-screw extruder, twin-screw extruder, or kneader. The melt-kneading temperature is not particularly limited, but is usually in the range of 240 to 320°C.

[0054] One form of the resin composition of this embodiment is a pellet. The resin composition or pellets of this embodiment are molded into various molded articles. That is, the molded articles of this embodiment are molded articles formed from the resin composition or pellets of this embodiment. There is no particular method for molding the molded articles, but examples include injection molding, ultra-high-speed injection molding, injection compression molding, two-color molding, hollow molding methods such as gas-assisted molding, molding using a heat-insulating mold, molding using a rapidly heated mold, foam molding (including supercritical fluid), insert molding, IMC (in-mold coating) molding, extrusion molding, sheet molding, thermoforming, rotational molding, lamination molding, press molding, blow molding, etc., with injection molding being preferred among them.

[0055] Furthermore, there are no particular restrictions on the shape of the molded product in this embodiment, and it can be appropriately selected according to the application and purpose of the molded product. Examples include plate-shaped, rod-shaped, sheet-shaped, film-shaped, cylindrical, annular, circular, elliptical, polygonal, irregularly shaped, hollow, frame-shaped, box-shaped, panel-shaped, and other special shapes.

[0056] The molded articles of this embodiment are preferably used as structural members, portable electronic device components, vehicle and medical device components, other electronic components including electrical circuits and their housings, food and pharmaceutical containers, and composite materials for forming these. [Examples]

[0057] The present invention will be described in more detail below with reference to examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate, as long as they do not depart from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or other reasons, measurements can be taken using other instruments with equivalent performance.

[0058] 1.Raw materials The following ingredients were used. [Table 1]

[0059] In the table above, the average particle size is shown as the D50 value.

[0060] 2. Examples 1-5, Comparative Examples 1-6 <Manufacturing of resin compositions (pellets)> The components shown in Table 1 were blended in the proportions (parts by mass) indicated in Tables 2 and 3, mixed in a tumbler for 20 minutes, and then supplied from the upstream feeder to a twin-screw extruder (TEX30α) manufactured by Japan Steel Works, Ltd., equipped with one vent. The mixture was kneaded under the conditions of a rotation speed of 200 rpm, a discharge rate of 30 kg / hour, and a barrel temperature of 280°C. The molten resin composition extruded in strand form from the extruder was rapidly cooled in a water bath and pelletized using a pelletizer to obtain pellets of the polycarbonate resin composition.

[0061] <Charpy impact strength with notch> After drying the pellets obtained above at 120°C for 5 hours, 3 mm thick ISO multipurpose test specimens were molded using a Nissei Plastic Industrial Co., Ltd. injection molding machine "NEX80III" under conditions of cylinder temperature 280°C and mold temperature 80°C. In accordance with ISO 179-1, the notched Charpy impact strength (unit: kJ / m²) was measured using ISO multipurpose test specimens at 23°C and -40°C. 2 ) was measured. Furthermore, after immersing the aforementioned ISO multipurpose test specimen in 82°C hot water for 168 hours, the moisture on the surface of the test specimen was wiped off, and the notched Charpy impact strength (unit: kJ / m) at 23°C was measured. 2 The following measurements were taken, and the retention rate of Charpy impact strength after immersion in hot water was measured according to the formula below. The percentage of Charpy impact strength retention after immersion in hot water (%) = (Notched Charpy impact strength at 23°C after immersion in hot water / Notched Charpy impact strength at 23°C before immersion in hot water) × 100

[0062] <Flame retardancy evaluation: UL94 test> The pellets obtained by the method described above were dried at 120°C for 5 hours, and then injection molded using a Sumitomo Heavy Industries SE100DU injection molding machine under conditions of cylinder temperature 280°C and mold temperature 80°C to form UL test specimens measuring 125 mm in length, 13 mm in width, and 1.5 mm in thickness. The flame retardancy was evaluated using the UL test specimens obtained above, in accordance with the UL-94 test (combustion test for plastic materials for equipment components) established by Underwriters Laboratories (UL) in the United States. A total of 10 flame exposures were performed on 5 test specimens, and the total flame burning time (seconds) was determined. Furthermore, after immersing the UL test specimen in 82°C hot water for 168 hours, the moisture on the surface of the specimen was wiped off, and the total flame burning time (seconds) was determined in the same manner as described above.

[0063] [Table 2]

[0064] [Table 3]

[0065] As is clear from the above results, molded articles formed from the resin composition of the present invention exhibited excellent impact resistance at room temperature and low temperature, and further exhibited excellent flame retardancy and flame retardancy after moist heat treatment (Examples 1-5). They also exhibited excellent impact resistance after moist heat treatment (Examples 1-5). In contrast, when inorganic particles and elastomers were not included (Comparative Example 1), the impact resistance at low temperatures and impact resistance after moist heat treatment were inferior. When inorganic particles were not included but elastomers were included, the impact resistance at low temperatures was insufficient (Comparative Example 2). Increasing the amount of elastomer compared to Comparative Example 2 improved the impact resistance at low temperatures, but the flame retardancy, especially the flame retardancy after moist heat treatment, deteriorated significantly (Comparative Example 3). On the other hand, when inorganic particles with a larger particle size were incorporated, the impact resistance after low-temperature and moist heat treatment was poor (Comparative Example 4). When the amount of inorganic particles with a larger particle size was increased, an improvement in impact resistance after moist heat treatment was observed, but the impact resistance at low temperatures was insufficient (Comparative Example 5). On the other hand, even when inorganic particles (C) with an average particle size of 0.01 to 0.4 μm were used, the impact resistance at low temperatures and the impact resistance after moist heat treatment were insufficient when the amount added was small (Comparative Example 6).

[0066] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications are possible without departing from the intent and scope of the invention.

Claims

1. A resin composition comprising 100 parts by mass of polycarbonate resin (A), 0.01 to 0.3 parts by mass of a metal salt flame retardant (B), and 2.5 to 10 parts by mass of inorganic particles (C) having an average particle size of 0.01 to 0.4 μm.

2. The resin composition according to claim 1, wherein the inorganic particles (C) include silica.

3. The resin composition according to claim 1 or 2, wherein the inorganic particles (C) are surface-treated with a surface treatment agent.

4. Furthermore, the resin composition according to claim 1 or 2, wherein the polycarbonate resin (A) contains more than 0 parts by mass and 1 part by mass or less of a sagging prevention agent (D) per 100 parts by mass.

5. The resin composition according to claim 1 or 2, wherein the elastomer content is less than 1 part by mass per 100 parts by mass of the polycarbonate resin (A).

6. The inorganic particles (C) contain silica, The inorganic particles (C) are surface-treated with a surface treatment agent. Furthermore, the polycarbonate resin (A) contains more than 0 parts by mass and 1 part by mass or less of a sagging prevention agent (D) per 100 parts by mass. The resin composition according to claim 1, wherein the elastomer content is less than 1 part by mass per 100 parts by mass of the polycarbonate resin (A).

7. Pellets of the resin composition according to claim 1, 2, or 6.

8. A molded article formed from the resin composition according to claim 1, 2, or 6.

9. A molded article formed from the pellets described in claim 7.

Images