Resin composition, molded article, electronic apparatus, and electric apparatus

Abstract

To provide a resin composition which can suppress lowering of flame retardancy and strength, and a molded article molded by the resin composition.SOLUTION: There are provided a resin composition, a molded article, an electronic apparatus, and an electric apparatus. The resin composition contains polyolefin, a dialkylphosphinic acid metal salt and a monoalkylphosphinic acid, a ratio of the dialkylphosphinic acid metal salt to the resin composition is 1 mass% or more and 20 mass% or less, and a ratio of the monoalkylphosphinic acid to the dialkylphosphinic acid metal salt is 1 mass% or more and 20 mass% or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a resin composition, a molded article using the resin composition, and an electronic device and an electric device having the molded article. [Background technology]

[0002] Molded articles of resin compositions are sometimes used as interior and exterior materials for electronic devices including copiers, etc. Examples of thermoplastic resins contained in such resin compositions include polyolefin resins.

[0003] In order to improve the flame retardancy of a resin composition containing a polyolefin resin, it is conceivable to use various flame retardants such as halogen-based, phosphorus-based, and metal hydrate-based flame retardants.

[0004] For example, Patent Document 1 discloses a flame-retardant resin composition in which a specific amount of a flame retardant made of silicone oil, silicone resin, and a phosphorus-containing nitrogen compound (ammonium polyphosphate) is added to polypropylene.

[0005] Patent Document 2 discloses a flame-retardant resin composition in which a specific amount of a phenol resin, a phosphorus-containing compound (red phosphorus), and expandable graphite are blended with a polyolefin resin. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 14277 / 1983 [Patent Document 2] Japanese Patent Application Publication No. 9-111059 Summary of the Invention [Problem to be solved by the invention]

[0007] The above-mentioned polyolefin resins have the disadvantage of being inferior in flame retardancy because their chemical structure has smaller intermolecular forces and they tend to rotate with only single bonds compared to polycarbonate, ABS resin, etc. In order to improve the flame retardancy of polyolefin resins, a large amount of flame retardant is often required, but using a large amount of flame retardant leads to a decrease in strength.

[0008] An object of the present invention is to provide a resin composition capable of suppressing deterioration in flame retardancy and strength, a molded article molded from the resin composition, an electronic device having the molded article, and an electrical device having the molded article. [Means for solving the problem]

[0009] The present invention relates to the following resin composition, molded article, electronic device, and electric device. [1] A resin composition comprising a polyolefin, a metal dialkylphosphinic acid, and a monoalkylphosphinic acid, wherein a ratio of the metal dialkylphosphinic acid to the resin composition is 1% by mass or more and 20% by mass or less, and a ratio of the monoalkylphosphinic acid to the metal dialkylphosphinic acid is 1% by mass or more and 20% by mass or less. [2] The resin composition according to [1], wherein the ratio of the metal dialkylphosphinic acid salt to the resin composition is 2% by mass or more and 5% by mass or less. [3] The resin composition according to [1] or [2], wherein the ratio of the monoalkylphosphinic acid to the metal dialkylphosphinic acid is 5% by mass or more and 20% by mass or less. [4] The resin composition according to any one of [1] to [3], wherein the polyolefin is polypropylene. [5] The resin composition according to any one of [1] to [4], wherein the metal dialkylphosphinic acid salt is aluminum diethylphosphinate. [6] The resin composition according to any one of [1] to [5], wherein the monoalkylphosphinic acid is monoethylphosphinic acid. [7] A molded product made from the resin composition of any one of [1] to [6]. [8] An electronic device having the molded article according to [7]. [9] An electrical device having the molded article according to [7]. Effect of the Invention

[0010] According to the present invention, it is possible to provide a resin composition capable of suppressing deterioration in flame retardancy and strength, a molded article molded from the resin composition, an electronic device having the molded article, and an electrical device having the molded article. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The resin composition according to the embodiment of the present invention is a resin composition containing a polyolefin, a metal dialkylphosphinic acid salt, and a monoalkylphosphinic acid. The ratio of the metal dialkylphosphinic acid salt to the resin composition is 1% by mass or more and 20% by mass or less. The ratio of the monoalkylphosphinic acid to the metal dialkylphosphinic acid salt is 1% by mass or more and 20% by mass or less.

[0012] The reason why the decrease in flame retardancy and strength of the molded article made from the resin composition is suppressed is presumed to be as follows. Dialkylphosphinic metal salts are particulate flame retardants that do not decompose at high temperatures (approximately 300°C) during kneading and molding. In other words, dialkylphosphinic metal salts are present in a particulate state in molded articles made from the resin composition. In general, the more the amount of flame retardant, the higher the flame retardancy can be, but if a particulate flame retardant such as dialkylphosphinic metal salt is present in a large amount in a molded article, the strength of the molded article decreases.

[0013] In the resin composition according to the present embodiment, in addition to the dialkylphosphinic metal salt, monoalkylphosphinic acid is also included as a flame retardant. This makes it possible to achieve both flame retardancy and strength. Although the mechanism is not entirely clear, it is speculated as follows.

[0014] It is generally known that low molecular weight compounds gather near the surface of a molded article due to molding, and it is believed that monoalkylphosphinic acid, which has a low molecular weight, gathers near the surface of the molded article. Here, the mechanism by which a flame retardant exhibits flame retardancy is believed to be the radical trapping effect in the gas phase, and it is believed that the monoalkylphosphinic acid gathered near the surface of the molded article promotes the radical trapping effect in the gas phase. In this way, it is believed that by incorporating an appropriate amount of monoalkylphosphinic acid into a resin composition containing a dialkylphosphinic acid metal salt, it is possible to suppress the decrease in flame retardancy even if the amount of dialkylphosphinic acid metal salt is reduced to 20 mass% or less relative to the resin composition. It is also believed that the decrease in strength can be suppressed. From the above, it is considered that the higher the ratio of monoalkylphosphinic acid, the more the decrease in strength and the decrease in flame retardancy can be suppressed. However, if the ratio of monoalkylphosphinic acid to the dialkylphosphinic metal salt is too high, the flame retardancy decreases. Although the mechanism is not entirely clear, it is considered that too much monoalkylphosphinic acid decomposes the dialkylphosphinic metal salt. Therefore, it is considered that the ratio of monoalkylphosphinic acid to the dialkylphosphinic metal salt is preferably 1% by mass or more and 20% by mass or less.

[0015] The polyolefin, the metal dialkylphosphinic acid salt, and the monoalkylphosphinic acid contained in the resin composition according to the present embodiment will be described below. In addition, other components that may be contained in the resin composition according to the present embodiment will also be described.

[0016] (Polyolefin) Polyolefin is the base material of the resin composition. The polyolefin may be a homopolymer or copolymer polymerized with olefin as the main monomer component. Here, the "olefin" may be an aliphatic chain unsaturated hydrocarbon having one double bond.

[0017] Polyolefins include copolymers of olefins with other olefins, or copolymers of olefins with other monomers copolymerizable with olefins.

[0018] The olefin is preferably an α-olefin having a carbon number of 2 to 12. Examples of the α-olefin include ethylene, propylene, 1-butene, isobutene, 1-pentene, 3-methyl-1-butene, 1-hexene, 1-octene, 1-decene, and 1-dodecene. The olefin may be used alone or in combination of two or more kinds.

[0019] Examples of other monomers copolymerizable with α-olefins include cyclic olefins such as cyclopentene and norbornene, and dienes such as 1,4-hexadiene and 5-ethylidene-2-norbornene. Examples of other monomers include monomers such as vinyl acetate, styrene, (meth)acrylic acid and its derivatives, vinyl ether, maleic anhydride, carbon monoxide, and N-vinylcarbazole. When polymerizing polyolefins, one type of other monomer may be used alone, or two or more types may be used in combination. Note that "(meth)acrylic acid" means at least one of acrylic acid and methacrylic acid.

[0020] Examples of polyolefins include polyethylenes based on ethylene, such as high density polyethylene (HDPE), low density polyethylene (LDPE), and linear low density polyethylene (LLDPE), polypropylene resins based on propylene, such as polypropylene (propylene homopolymer), ethylene-propylene copolymers, propylene-butene copolymers, ethylene-propylene-butene copolymers, and ethylene-propylene-diene copolymers, polybutene, and polypentene.

[0021] Examples of polyolefin resins further include ethylene-vinyl acetate copolymers (EVA), ethylene-ethyl acrylate copolymers, polyketones, copolymers produced with metallocene catalysts, and also include those obtained by chemically reacting or modifying these polymers, specifically ionomer resins, saponified EVA, and olefin elastomers produced by dynamic vulcanization in an extruder.

[0022] The polyolefin resin is preferably a polyethylene resin or a polypropylene resin, more preferably a polypropylene resin. The stereoregularity of the structure derived from propylene in the polypropylene resin may be any of isotactic, syndiotactic and atactic.

[0023] Examples of commercially available polyolefins include the following: Prime Polymer's polypropylene resins "Prime Polypro", "Polyfine", and "Prime TPO" series (e.g., Prime Polypro J715M); Prime Polymer's polyethylene resins "Hi-Zex", "Neo-Zex", "Ult-Zex", "Moatec", and "Evolu" series (e.g., Hi-Zex 1300J).

[0024] As the polyolefin, polypropylene is preferable, and propylene homopolymer is more preferable, from the viewpoint of easily increasing the strength and heat resistance of the molded product.

[0025] The ratio of polyolefin to the resin composition is in the range of 29.0% by mass to 98.0% by mass, preferably in the range of 50% by mass to 93.95% by mass. When the ratio of polyolefin to the resin composition is 29.0% by mass or more, the properties of polyolefin are more easily obtained, and when it is 93.95% by mass or less, the strength of the molded product is more easily increased.

[0026] The method for detecting polyolefin is not particularly limited. Polyolefin can be detected by known methods. For example, polyolefin can be detected by combining IR (infrared spectroscopy), DSC (differential scanning calorimetry), NMR (nuclear magnetic resonance spectroscopy), etc. Specifically, for example, a resin composition or a molded article is frozen and crushed, and the solution obtained by dissolving in chloroform is measured by NMR to detect polyolefin.

[0027] (Dialkylphosphinic acid metal salts) The metal dialkylphosphinate functions as a flame retardant. The metal dialkylphosphinate may include compounds that may be represented by the following formula:

[0028] [ka]

[0029] R 1 and R 2 may each independently be an alkyl having 1 to 8 carbon atoms. n and m may each take a value of 1 to 3. M may be a metal. Examples of metals include metals that can become cations. Examples of metals include alkali metals, alkaline earth metals, aluminum, etc.

[0030] Dialkylphosphinic acid metal salts are R 1 and R 2 Aluminum diethylphosphinate, in which is an ethyl group and M is aluminum, is preferred.

[0031] The ratio of the dialkylphosphinic acid metal salt to the resin composition is as follows from the viewpoint of improving flame retardancy. It is sufficient that it is 1% by mass or more, more preferably 2% by mass or more, more preferably 5% by mass or more, more preferably 7% by mass or more, more preferably 10% by mass or more, and more preferably 15% by mass or more. On the other hand, from the viewpoint of improving strength, the ratio of the dialkylphosphinic acid metal salt to the resin composition is sufficient to be 20% by mass or less, more preferably 15% by mass or less, more preferably 10% by mass or less, and more preferably 5% by mass or less. From the viewpoint of achieving both flame retardancy and strength, the ratio of the dialkylphosphinic acid metal salt to the resin composition is sufficient to be 1% by mass or more and 20% by mass or less, and more preferably 2% by mass or more and 5% by mass or less.

[0032] The method for detecting the dialkylphosphinic metal salt is not particularly limited. The dialkylphosphinic metal salt can be detected by a known method. For example, the dialkylphosphinic metal salt can be detected by ion chromatography, capillary electrophoresis, or ICP-AES (inductively coupled plasma atomic emission spectrometry). It can also be detected by combining ICP-MS (inductively coupled plasma mass spectrometry), atomic absorption spectrometry, X-ray fluorescence spectrometry, NMR, and the like. Specifically, for example, the resin composition or molded product is frozen and crushed, and the solution obtained by dissolving in chloroform is measured by NMR to detect the presence of the dialkylphosphinic metal salt.

[0033] (Monoalkylphosphinic acid) Monoalkylphosphinic acid functions as a flame retardant. It is assumed that monoalkylphosphinic acid is likely to exist near the surface of a molded article, and effectively exerts a radical trap effect in the gas phase to exert flame retardancy. Monoalkylphosphinic acid may include a compound that can be represented by the following formula:

[0034] [ka]

[0035] R may be any alkyl having a carbon number of 1 to 8. The monoalkylphosphinic acid is preferably monoethylphosphinic acid in which R is ethyl.

[0036] The content of monoalkylphosphinic acid in the resin composition is preferably adjusted by the ratio to the dialkylphosphinic metal salt. That is, the ratio of monoalkylphosphinic acid to the dialkylphosphinic metal salt is preferably 20% by mass or less. The ratio of monoalkylphosphinic acid to the dialkylphosphinic metal salt is preferably 1% by mass or more, and more preferably 5% by mass or more. The ratio of monoalkylphosphinic acid to the dialkylphosphinic metal salt is preferably 1% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 20% by mass or less. If the ratio of monoalkylphosphinic acid to the dialkylphosphinic metal salt is less than 1% by mass, the flame retardancy decreases. In addition, even if the ratio of monoalkylphosphinic acid to the dialkylphosphinic metal salt is 20% by mass or more, the flame retardancy decreases. This is presumably because, in a heated state during kneading of the resin composition, the dialkylphosphinic metal salt reacts with the monoalkylphosphinic acid, and the dialkylphosphinic metal salt is decomposed.

[0037] The proportion of monoalkylphosphinic acid in the resin composition may be, for example, from 0.1% by mass to 3% by mass.

[0038] The detection method of monoalkylphosphinic acid is not particularly limited. Monoalkylphosphinic acid can be detected by known methods. For example, monoalkylphosphinic acid can be detected by the following or a combination of the following: ion chromatography, capillary electrophoresis, ICP-AES (inductively coupled plasma atomic emission spectrometry), ICP-MS (inductively coupled plasma mass spectrometry). Also, atomic absorption spectrometry, X-ray fluorescence spectrometry, and NMR. Specifically, for example, the resin composition or molded product is frozen and crushed, and the solution dissolved in chloroform is measured by NMR to detect.

[0039] (Other Ingredients) The resin composition may contain other components within a range that does not impair the effects of the present invention. Examples of other components include flame retardants other than the above-mentioned flame retardants, fillers, impact modifiers, crystal nucleating agents, antioxidants, light resistance stabilizers, antistatic agents, lubricants, plasticizers, pigments, dyes, etc. The resin composition may also contain known components as additives. Each of these will be described below.

[0040] <Other flame retardants> Examples of other flame retardants include phosphorus-based flame retardants such as phosphate esters, ammonium polyphosphate, and guanidine phosphate, nitrogen-based flame retardants such as melamine cyanurate and guanidine compounds, and silicone-based flame retardants. The other flame retardants may be used alone or in combination of two or more.

[0041] <Filling agent> Fillers are broadly classified into organic fillers and inorganic fillers. Examples of organic fillers include starch, cellulose fine particles, cellulose fibers, wood flour, soybean pulp, rice husks, bran, and other naturally derived polymers and their modified products. In addition, high-melting organic fibrous materials such as polyamides, fluororesins, and acrylic resins can also be used.

[0042] As the inorganic filler, a fibrous, powdery or plate-like filler is used. Examples of fibrous fillers include glass fiber, carbon fiber, silica fiber, silica-alumina fiber, and zirconia fiber. In addition, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, wollastonite, barium sulfate fiber, and metal fibrous materials such as stainless steel, aluminum, titanium, copper, and brass are also included.

[0043] Examples of powdered and granular fillers include carbon black, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay, diatomaceous earth, iron oxide, titanium oxide, alumina, and other metal oxides. In addition, metal carbonates such as calcium carbonate and magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate, silicon carbide, silicon nitride, boron nitride, and various metal powders are included. Examples of plate-like inorganic fillers include mica, glass flakes, layered silicates, and various metal foils. The fillers may be used alone or in combination of two or more.

[0044] <Impact modifier> The impact modifier is preferably a thermoplastic elastomer mainly composed of structural units derived from olefins, such as ethylene propylene diene rubber (EPDM). The impact modifier may also be a thermoplastic elastomer, and is preferably one containing structural units derived from olefins. Examples of thermoplastic elastomers include methyl methacrylate-butadiene-styrene copolymer (MBS) and acrylonitrile-butadiene-styrene copolymer (ABS). Also included are styrene-butadiene-styrene copolymer (SBS), styrene-ethylene-butylene-styrene block copolymer (SEBS), ethylene-octene copolymer (EOR) and butyl acrylate-methyl methacrylate copolymer. From the viewpoints of compatibility and flame retardancy of the resin composition and dispersibility of the thermoplastic elastomer in the resin composition, SEBS and EOR are preferred as the impact modifier. One type of impact modifier may be used alone, or two or more types may be used in combination.

[0045] <Nucleating agent> The crystal nucleating agent may be a known one. Examples of the crystal nucleating agent include metal salts of carboxylic acids, dibenzyl sorbitol derivatives, and alkali metal salts of phosphoric acid. Specific examples of the crystal nucleating agent include sodium benzoate, aluminum adipate, pt-butyl aluminum benzoate, and 1,3,2,4-dibenzylidene sorbitol. Also, 1,3,2,4-bis(p-methyl-benzylidene) sorbitol, and 1,3,2,4-bis(p-ethylbenzylidene) sorbitol. Also, 1,3-p-chlorobenzylidene-2,4-p-methylbenzylidene) sorbitol, sodium bis(4-t-butylphenyl) phosphate, and sodium bis(4-t-methylphenyl) phosphate are included. Also, potassium bis(4,6-di-t-butylphenyl) phosphate and sodium 2,2'-methylene-bis(4,6-di-t-butylphenyl) phosphate are included. Also included is sodium 2,2'-ethylidene-bis(4,6-di-t-butylphenyl)phosphate. The crystal nucleating agent may be used alone or in combination of two or more kinds.

[0046] <Antioxidants> Examples of the antioxidant include phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. The antioxidant is preferably a phenol-based antioxidant, and more preferably an alkyl-substituted phenol-based antioxidant. The antioxidant may be used alone or in combination of two or more kinds.

[0047] <Light resistance stabilizer> Examples of the light resistance stabilizer include benzophenone-based light resistance stabilizers, benzotriazole-based light resistance stabilizers, and NH-type and N-methyl-type hindered amine-based light resistance stabilizers. The light resistance stabilizers may be used alone or in combination of two or more types.

[0048] <Antistatic agent> Examples of the antistatic agent include cationic antistatic agents such as fatty acid quaternary ammonium ion salts and polyamine quaternary salts; higher alcohol phosphate salts, higher alcohol EO adducts, and polyethylene glycol fatty acid esters. Also included are anionic alkylsulfonates, higher alcohol sulfate salts, and higher alcohol ethylene oxide adduct sulfate salts. Also included are anionic antistatic agents such as higher alcohol ethylene oxide adduct phosphate salts; and nonionic antistatic agents such as polyhydric alcohol fatty acid esters, polyglycol phosphate esters, and polyoxyethylene alkyl allyl ethers. Also included are amphoteric alkyl betaines such as alkyl dimethylamino acetate betaines, and amphoteric antistatic agents such as imidazoline amphoteric surfactants. The antistatic agent may be used alone or in combination of two or more types.

[0049] <Lubricant> Examples of lubricants include fatty acid salts, fatty acid amides, silane polymers, solid paraffin, liquid paraffin, magnesium stearate, calcium stearate, zinc stearate, stearic acid amide, and silicone powder. Also included are methylene bisstearic acid amide and N,N'-ethylene bisstearic acid amide. The lubricants may be used alone or in combination of two or more.

[0050] <Plasticizer> Examples of the plasticizer include polyethylene glycol, polyamide oligomer, ethylene bisstearamide, phthalate ester, adipate ester, polystyrene oligomer, polyethylene wax, silicone oil, and mineral oil. One type of plasticizer may be used alone, or two or more types may be used in combination.

[0051] The content of other additives in the resin composition of the present invention is within a range that does not impair the effects of the present invention, and is, for example, within a range of about 0.1 to 30 mass %, preferably within a range of 0.1 to 20 mass %, relative to the total mass of the resin composition.

[0052] The method for producing the resin composition is not particularly limited. For example, the resin composition can be produced by mixing the respective components and melt-kneading the mixture.

[0053] The melt kneading in this embodiment is carried out using a kneading device such as a Banbury mixer, a roll, a plastograph, an extruder (such as a single-screw extruder or a multi-screw extruder (e.g., a twin-screw extruder)), or a kneader. From the viewpoint of production efficiency, it is preferable to use an extruder for the melt kneading. Furthermore, from the viewpoint of being able to impart high shear properties, it is more preferable to use a multi-screw extruder, and particularly preferably a twin-screw extruder, for the melt kneading. Here, the term extruder is used in a category that includes an extrusion kneader.

[0054] The temperature during melt kneading (melt kneading temperature) is equal to or higher than the melting temperature of the polyolefin resin. The melt kneading temperature is preferably 150 to 250°C and is appropriately selected depending on the polyolefin resin used. When a polypropylene resin is used as the polyolefin resin, the melt kneading temperature is preferably 160 to 220°C. When an extruder is used for melt kneading, the kneading melt temperature corresponds to the cylinder temperature.

[0055] Prior to melt-kneading, the components may be pre-mixed (dry blended) using various mixers such as a tumbler or a high-speed mixer known as a Henschel mixer.

[0056] In the manufacturing method of this embodiment, the molten kneaded material is extruded into a strand shape, and then the extruded strand shape can be processed into a pellet-like, flake-like, or other shape.

[0057] The resin composition of the present invention can be in various forms such as powder, granules, tablets, pellets, and flakes.

[0058] The resin composition in the embodiment can be molded into any shape to produce a molded article. Examples of molding methods for the molded article include injection molding, extrusion molding, blow molding, vacuum molding, profile extrusion molding, compression molding, and gas-assisted molding.

[0059] When an injection molded article is manufactured using the resin composition of the present embodiment, a conventionally known injection molding machine can be used. The injection molded article can be manufactured by melting the resin composition in a cylinder, injecting the molten resin composition into a mold, and cooling and solidifying it. The injection speed and pressure are appropriately adjusted. The conditions for injection molding are preferably, for example, a cylinder temperature (melting temperature) of 170 to 230°C and a mold temperature of 40 to 80°C.

[0060] The shape and dimensions of the molded article are not particularly limited and can be set arbitrarily depending on the application of the molded article.

[0061] The molded articles can be used for interior or exterior parts of electric or electronic equipment such as home appliances, office automation and media-related equipment, optical equipment, and communication equipment, as well as automobiles, machine parts, and housing and building materials. The molded articles have excellent strength and good flame retardancy, and are suitable for use as exterior parts (especially housings) of electric or electronic equipment such as copiers, printers, personal computers, and televisions, because of their low environmental impact. EXAMPLES

[0062] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples.

[0063] [Example 1] A KTX-30 (manufactured by Kobe Steel) was used as a twin-screw kneader. 94.2% by mass of polypropylene ("J715M" (manufactured by Prime Polymer) was used as a resin. 5% by mass of aluminum diethylphosphinate ("Exolit OP1230" (manufactured by Clariant) was used as a flame retardant. 0.8% by mass of monoethylphosphinic acid ("JAMP-2" (manufactured by Johoku Chemical Industry Co., Ltd.) was used. The resin composition of Example 1 was obtained by melt kneading at a cylinder temperature of 190°C and a screw rotation speed of 200 rpm.

[0064] [Example 2] A resin composition of Example 2 was obtained in the same manner as in Example 1, except that the content of polypropylene was 96.0% by mass, the content of aluminum diethylphosphinate was 3.5% by mass, and the content of monoethylphosphinic acid was 0.5% by mass.

[0065] [Example 3] A resin composition of Example 3 was obtained in the same manner as in Example 1, except that the content of polypropylene was 97.7% by mass, the content of aluminum diethylphosphinate was 2.0% by mass, and the content of monoethylphosphinic acid was 0.3% by mass.

[0066] [Example 4] A resin composition of Example 4 was obtained in the same manner as in Example 1, except that the content of polypropylene was 80.5% by mass, the content of aluminum diethylphosphinate was 17.5% by mass, and the content of monoethylphosphinic acid was 2.0% by mass.

[0067] [Example 5] A resin composition of Example 5 was obtained in the same manner as in Example 1, except that the content of polypropylene was 86.5% by mass, the content of aluminum diethylphosphinate was 12.5% ​​by mass, and the content of monoethylphosphinic acid was 1.0% by mass.

[0068] [Example 6] A resin composition of Example 6 was obtained in the same manner as in Example 1, except that the content of polypropylene was 91.8% by mass, the content of aluminum diethylphosphinate was 8.0% by mass, and the content of monoethylphosphinic acid was 0.2% by mass.

[0069] [Comparative Example 1] A resin composition of Comparative Example 1 was obtained in the same manner as in Example 1, except that the amount of polypropylene was 74.9% by mass, the amount of aluminum diethylphosphinate was 25.0% by mass, and the amount of monoethylphosphinic acid was 0.1% by mass.

[0070] [Comparative Example 2] A resin composition of Comparative Example 2 was obtained in the same manner as in Example 1, except that the content of polypropylene was 99.4% by mass, the content of aluminum diethylphosphinate was 0.5% by mass, and the content of monoethylphosphinic acid was 0.1% by mass.

[0071] [Comparative Example 3] A resin composition of Comparative Example 3 was obtained in the same manner as in Example 1, except that the content of polypropylene was 93.5% by mass, the content of aluminum diethylphosphinate was 4.5% by mass, and the content of monoethylphosphinic acid was 2.0% by mass.

[0072] [Comparative Example 4] A resin composition of Comparative Example 4 was obtained in the same manner as in Example 1, except that the amounts of polypropylene, triphenylphosphine, and monoethylphosphinic acid were 96.0% by mass, 3.5% by mass, and 0.5% by mass, respectively.

[0073] [Comparative Example 5] A resin composition of Comparative Example 5 was obtained in the same manner as in Example 1, except that the contents of polypropylene were 97.7% by mass, aluminum diethylphosphinate were 2.0% by mass, and tricresyl phosphate were 0.3% by mass.

[0074] The formulations of the resin compositions of Example 1 to Comparative Example 5 are shown in Table 1 below.

[0075] [Table 1]

[0076] [evaluation] The resin compositions of Examples 1 to 6 and Comparative Examples 1 to 5 obtained as described above were subjected to a flame retardancy test and a strength test as follows.

[0077] (1) Flame retardancy test The resin compositions of each Example and Comparative Example were dried at 80°C for 4 hours, and then molded into rectangular test pieces with a length of 120 mm, a width of 10 mm, and a thickness of 1.6 mm using an injection molding machine (ROBOSHOT S-2000i50Bp, manufactured by FANUC CORPORATION) under conditions of a cylinder temperature of 170 to 200°C and a mold temperature of 80°C, and a flame retardancy test was performed.

[0078] The flame retardancy test was conducted in accordance with the well-known UL94 (UL94 flammability evaluation method) established by Underwriters Laboratories (UL) of the United States, after the above test specimens were conditioned in a temperature-controlled room at 23°C and humidity of 50% for 48 hours, and then stored in a temperature-controlled room at 70°C for 168 hours. In this method, the burning time (time until the flame goes out) is measured after the test specimen is exposed to a flame, and the flame is exposed twice. In Table 2, the burning times t1 and t2 indicate the first and second burning times, respectively.

[0079] The test pieces of each of the examples and comparative examples were evaluated, and the evaluation results were classified as follows. ◎: V2 and the average of the first and second burning times is less than 10 seconds ○: V2 and first burn time is 10 seconds or more but less than 20 seconds △: V2 and burning time is between 20 and 30 seconds ×: Not V (burning time is 30 seconds or more) (failed)

[0080] (2) Strength test (Charpy impact test) Pellets of the resin composition of each Example and Comparative Example were dried at 80°C for 4 hours, and then molded using an injection molding machine (ROBOSHOT S-2000i50Bp, manufactured by FANUC CORPORATION). Test pieces for evaluating Charpy impact strength (total length 80 mm, width 10 mm, thickness 4 mm, notch width 8 mm) were molded under conditions of a cylinder temperature of 170 to 200°C and a mold temperature of 80°C. The Charpy impact strength was measured using the obtained test pieces in accordance with ISO179. The Charpy impact strength was measured for 10 test pieces, and the number average value was calculated. The following evaluation criteria were passed when they were "◎" or "○", and failed when they were "×".

[0081] Evaluation criteria ◎: 15kJ / m 2 End ○: 10kJ / m 2 More than 15kJ / m 2 less than ×:10kJ / m 2 less than

[0082] The evaluation results are shown in Table 2 below.

[0083] [Table 2]

[0084] As can be seen from Tables 1 and 2, the decrease in flame retardancy and the decrease in strength were suppressed in Examples 1 to 6. This is because in Examples 1 to 6, the ratio of the metal dialkylphosphinic acid to the resin composition was 1% by mass or more and 20% by mass or less, and the ratio of the monoalkylphosphinic acid to the metal dialkylphosphinic acid was 1% by mass or more and 20% by mass or less.

[0085] Comparing Example 2 and Comparative Example 4 in Table 1, Example 2 contains both aluminum diethylphosphinate and monoethylphosphinic acid. However, Comparative Example 4 contains monoethylphosphinic acid but does not contain aluminum diethylphosphinate, but contains triphenylphosphine instead. As shown in Table 2, Comparative Example 4 had low flame retardancy and strength, but Example 2 had high flame retardancy and strength. Thus, when the resin composition contains both aluminum diethylphosphinate and monoethylphosphinic acid, it is possible to increase the flame retardancy and strength.

[0086] Comparing Example 3 and Comparative Example 5 in Table 1, Example 3 contains both aluminum diethylphosphinate and monoethylphosphinic acid. However, Comparative Example 5 contains aluminum diethylphosphinate. However, it does not contain monoethylphosphinic acid, but contains tricresyl phosphate instead. As shown in Table 2, Comparative Example 5 had low flame retardancy and strength, but Example 3 had high flame retardancy and strength. Thus, when the resin composition contains both aluminum diethylphosphinate and monoethylphosphinic acid, it is possible to increase the flame retardancy and strength.

[0087] From the above Examples 2 and 3 and Comparative Examples 4 and 5, it can be seen that when the resin composition contains both aluminum diethylphosphinate and monoethylphosphinic acid, the flame retardancy and strength can be increased. This is presumed to be due to the existence of some kind of interaction between aluminum diethylphosphinate and monoethylphosphinic acid that improves the flame retardancy and strength. Specifically, it is presumed that the monoethylphosphinic acid, which is a low molecular weight, gathers near the surface of the molded article as described above, promoting the radical trapping effect in the gas phase.

[0088] Although the resin composition of Comparative Example 1 contained aluminum diethylphosphinate and monoethylphosphinic acid, the strength was decreased. This is because the ratio of aluminum diethylphosphinate to the resin composition of Comparative Example 1 was as high as 25% by mass.

[0089] Although Comparative Example 2 contained aluminum diethylphosphinate and monoethylphosphinic acid, the flame retardancy was decreased because the ratio of aluminum diethylphosphinate to the resin composition in Comparative Example 2 was as low as 0.5% by mass.

[0090] Comparing Example 1 with Comparative Example 3, although both contain aluminum diethylphosphinate and monoethylphosphinic acid, the flame retardancy was decreased in Comparative Example 3. This is presumably because in Comparative Example 3, the ratio of monoethylphosphinic acid to the metal diethylphosphinic acid was high at more than 20%, and aluminum diethylphosphinate was decomposed by monoethylphosphinic acid.

[0091] Moreover, Examples 1 to 3 in which the proportion of aluminum diethylphosphinate was 2% by mass or more and 5% by mass or less had higher strength than Examples 4 to 6 in which the proportion of aluminum diethylphosphinate was more than 5% by mass. [Industrial Applicability]

[0092] The resin composition of the present invention is useful for molding parts that require flame retardancy and strength.

Claims

1. A resin composition comprising a polyolefin, a metal salt of a dialkylphosphinic acid, and a monoalkylphosphinic acid, The ratio of the dialkylphosphinic acid metal salt to the resin composition is 1% by mass or more and 20% by mass or less, The ratio of the monoalkylphosphinic acid to the dialkylphosphinic acid metal salt is 1% by mass or more and 20% by mass or less. Resin composition.

2. The resin composition according to claim 1 , wherein the ratio of the metal dialkylphosphinic acid salt to the resin composition is 2% by mass or more and 5% by mass or less.

3. The resin composition according to claim 1 , wherein a ratio of the monoalkylphosphinic acid to the dialkylphosphinic acid metal salt is 5% by mass or more and 20% by mass or less.

4. The resin composition according to claim 1 , wherein the polyolefin is polypropylene.

5. The resin composition according to claim 1 , wherein the metal dialkylphosphinic acid salt is aluminum diethylphosphinate.

6. The resin composition according to claim 1 , wherein the monoalkylphosphinic acid is monoethylphosphinic acid.

7. A molded article molded from the resin composition according to any one of claims 1 to 6.

8. An electronic device comprising the molded product according to claim 7.

9. An electrical device comprising the molded article according to claim 7.

Images