Resin composition, molded article, electronic device, and electrical device

Abstract

The invention relates to a resin composition, a molded article, an electronic device, and an electrical device. This resin composition contains a polyolefin, a dialkylphosphinic acid metal salt, and a monoalkylphosphinic acid, and is characterized in that: the ratio of the dialkylphosphinic acid metal salt to the resin composition is 1-20 mass%; the ratio of the monoalkylphosphinic acid to the dialkylphosphinic acid metal salt is from 1% by mass to 20% by mass (inclusive).

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 Art

[0002] A molded article of a resin composition is sometimes used as an interior and exterior material of electronic equipment including a copying machine, etc. Examples of the thermoplastic resin contained in such a resin composition 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 composed of silicone oil, polysiloxane resin, and a phosphorus-nitrogen-containing compound (ammonium polyphosphate) is added to polypropylene.

[0005] Patent Document 2 discloses a flame-retardant resin composition in which a phenol resin, a phosphorus-containing compound (red phosphorus), and expandable graphite are blended in specific amounts into a polyolefin resin.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 64-14277

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 9-111059 Summary of the invention

[0010] Technical problem to be solved by the invention

[0011] Compared with polycarbonate, ABS resin, etc., polyolefin resins have weak intermolecular forces in chemical structure and are easy to rotate only through single bonds, so they have the disadvantage of poor flame retardancy. In order to improve the flame retardancy of polyolefin resins, a large amount of flame retardants are mostly required, but if a large amount of flame retardants are used, the strength is reduced.

[0012] An object of the present invention is to provide a resin composition capable of suppressing reduction in flame retardancy and strength, a molded article obtained by molding the resin composition, an electronic device having the molded article, and an electric device having the molded article.

[0013] Technical means to solve technical problems

[0014] The present invention relates to the following resin composition, molded article, electronic device and electric device.

[0015] [1] A resin composition comprising a polyolefin, a dialkylphosphinic acid metal salt and a monoalkylphosphinic acid, wherein the ratio of the dialkylphosphinic acid metal salt to the resin composition is 1% by mass or more and 20% by mass or less, and the ratio of the monoalkylphosphinic acid to the dialkylphosphinic acid metal salt is 1% by mass or more and 20% by mass or less.

[0016] [2] The resin composition according to [1], wherein the ratio of the metal dialkylphosphinate to the resin composition is 2% by mass or more and 5% by mass or less.

[0017] [3] The resin composition according to [1] or [2], wherein the ratio of the monoalkylphosphinic acid to the dialkylphosphinic acid metal salt is 5 mass % or more and 20 mass % or less.

[0018] [4] The resin composition according to any one of [1] to [3], wherein the polyolefin is polypropylene.

[0019] [5] The resin composition according to any one of [1] to [4], wherein the metal dialkylphosphinate is aluminum diethylphosphinate.

[0020] [6] The resin composition according to any one of [1] to [5], wherein the monoalkylphosphinic acid is monoethylphosphinic acid.

[0021] [7] A molded article molded from the resin composition according to any one of [1] to [6].

[0022] [8] An electronic device comprising the molded article described in [7].

[0023] [9] An electric device comprising the molded article described in [7].

[0024] Effects of the Invention

[0025] According to the present invention, a resin composition capable of suppressing reduction in flame retardancy and strength, a molded article obtained by molding the resin composition, an electronic device having the molded article, and an electric device having the molded article can be provided. DETAILED DESCRIPTION

[0026] The resin composition according to an embodiment of the present invention is a resin composition comprising a polyolefin, a dialkylphosphinic acid metal salt and a monoalkylphosphinic acid, wherein the ratio of the dialkylphosphinic acid metal salt to the resin composition is 1% by mass or more and 20% by mass or less, and the ratio of the monoalkylphosphinic acid to the dialkylphosphinic acid metal salt is 1% by mass or more and 20% by mass or less.

[0027] The reason why the flame retardancy and strength of a molded article molded from the resin composition are suppressed from decreasing is presumed to be as follows.

[0028] Dialkylphosphinate metal salt is a particulate flame retardant that does not decompose at high temperatures (about 300° C.) during mixing and molding. That is, in the molded product molded from the resin composition, the dialkylphosphinate metal salt exists in a particle state. Generally, the more the amount of flame retardant, the more it can improve the flame retardancy, but when a large amount of particulate flame retardants such as dialkylphosphinate metal salts are present in the molded product, the strength of the molded product is reduced.

[0029] The resin composition of this embodiment contains a monoalkylphosphinic acid as a flame retardant in addition to the dialkylphosphinic acid metal salt. Thus, both flame retardancy and strength can be achieved. The mechanism may not be clear, but it is speculated as follows.

[0030] It is known that low molecular weight compounds usually gather near the surface of the molded product by molding, and it is believed that low molecular weight monoalkyl phosphinic acid gathers near the surface of the molded product. Here, the mechanism by which the flame retardant shows flame retardancy is believed to be the free radical capture effect in the gas phase, and it is believed that the monoalkyl phosphinic acid gathered near the surface of the molded product promotes the free radical capture effect in the gas phase. In this way, it is believed that by appropriately including monoalkyl phosphinic acid in the resin composition containing dialkyl phosphinic acid metal salt, even if the amount of dialkyl phosphinic acid metal salt is less than 20% by mass relative to the resin composition, the reduction of flame retardancy can be suppressed, and the reduction of strength can also be suppressed.

[0031] It is also believed that the more the ratio of monoalkyl phosphinic acid, the more it can suppress the reduction of strength and the reduction of flame retardancy. However, when the ratio of monoalkyl phosphinic acid relative to dialkyl phosphinic acid metal salt is too much, flame retardancy is reduced. Although this mechanism may not be clear, it is believed that when monoalkyl phosphinic acid is too much, dialkyl phosphinic acid metal salt will be decomposed. Therefore, it is believed that it is preferred to make the ratio of monoalkyl phosphinic acid relative to dialkyl phosphinic acid metal salt be more than 1 mass % and less than 20 mass %.

[0032] Hereinafter, the polyolefin, the dialkylphosphinic acid metal salt, and the monoalkylphosphinic acid contained in the resin composition of the present embodiment will be described. In addition, other components that may be contained in the resin composition of the present embodiment will also be described.

[0033] (Polyolefin)

[0034] The polyolefin is used as the base material of the resin composition. The polyolefin may be any homopolymer or copolymer obtained by polymerizing an olefin as the main monomer component. Here, the "olefin" may be any aliphatic chain unsaturated hydrocarbon having one double bond.

[0035] The polyolefin includes a copolymer of an olefin and other olefins, or a copolymer of an olefin and other monomers copolymerizable with the olefin.

[0036] The olefin is preferably an α-olefin having 2 to 12 carbon atoms. Examples of the α-olefin include ethylene, propylene, 1-butene, isobutylene, 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.

[0037] 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. In addition, 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. Other monomers can be used alone or in combination of two or more when polymerizing polyolefins. It should be noted that "(meth)acrylic acid" refers to at least one of acrylic acid and methacrylic acid.

[0038] Examples of polyolefins include polyethylenes with ethylene as the main component, such as high-density polyethylene (HDPE), low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE); polypropylene resins with propylene as the main component, such as polypropylene (propylene homopolymer), ethylene-propylene copolymer, propylene-butene copolymer, ethylene-propylene-butene copolymer and ethylene-propylene-diene copolymer; polybutene; and polypentene.

[0039] Examples of polyolefin resins include ethylene-vinyl acetate copolymers (EVA), ethylene-ethyl acrylate copolymers, polyketones, and copolymers produced using metallocene catalysts. In addition, these polymers are also chemically reacted and modified, specifically, ionomer resins, saponified EVA, and olefin elastomers produced using dynamic vulcanization in an extruder.

[0040] The polyolefin resin is preferably a polyethylene resin or a polypropylene resin, and 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.

[0041] Examples of commercially available polyolefins include various series of polypropylene resins "PRIMEPOLYPRO", "POLYFINE", and "PRIME TPO" manufactured by PRIME POLYMER (for example, PRIME POLYPRO J715M), and various series of polyethylene resins "HI-ZEX", "NEO-ZEX", "ULT-ZEX", "MORETEC", and "EVOLUE" manufactured by PRIME POLYMER (for example, HI-ZEX 1300J).

[0042] From the viewpoint of easily improving the strength and heat resistance of a molded product, the polyolefin is preferably a polypropylene, and more preferably a propylene homopolymer.

[0043] The ratio of polyolefin to the resin composition is in the range of 29.0 mass % or more and 98.0 mass % or less, preferably in the range of 50 mass % or more and 93.95 mass %. When the ratio of polyolefin to the resin composition is 29.0 mass % or more, it is easy to further fully obtain the characteristics of polyolefin, and when it is 93.95 mass % or less, it is easy to further improve the strength of the molded article.

[0044] The detection method of polyolefin is not particularly limited. Polyolefin can be detected by a known method. For example, polyolefin can be detected by combining IR (infrared spectroscopy), DSC (differential scanning calorimetry), NMR (nuclear magnetic resonance spectroscopy), etc. Specifically, for example, the resin composition or the molded product is frozen and crushed, and the dissolved matter dissolved in chloroform is measured and detected by NMR.

[0045] (Dialkylphosphinate metal salt)

[0046] The metal dialkylphosphinate functions as a flame retardant. The metal dialkylphosphinate may include a compound represented by the following formula.

[0047] [Chemical formula 1]

[0048]

[0049] R 1 and R 2 Each independently may be an alkyl group having 1 to 8 carbon atoms. n and m may each be 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, and the like.

[0050] The metal dialkylphosphinate is preferably R 1 and R 2 Aluminum diethylphosphinate wherein M is ethyl and aluminum is aluminum.

[0051] From the viewpoint of improving flame retardancy, the ratio of dialkyl phosphinate metal salt to resin combination is 1 mass % or more, more preferably 2 mass % or more, more preferably 5 mass % or more, more preferably 7 mass % or more, more preferably 10 mass % or more, more preferably 15 mass % or more. On the other hand, from the viewpoint of improving strength, the ratio of dialkyl phosphinate metal salt to resin combination is 20 mass % or less, more preferably 15 mass % or less, more preferably 10 mass % or less, more preferably 5 mass % or less. From the viewpoint of taking into account both flame retardancy and strength, the ratio of dialkyl phosphinate metal salt to resin combination is 1 mass % or more and 20 mass % or less, more preferably 2 mass % or more and 5 mass % or less.

[0052] The detection method of the dialkylphosphinate metal salt is not particularly limited. The dialkylphosphinate metal salt can be detected by a known method. For example, the dialkylphosphinate metal salt can be detected by combining ion chromatography, capillary electrophoresis, ICP-AES (high-frequency inductively coupled plasma emission spectrometry), ICP-MS (inductively coupled plasma mass spectrometry), atomic absorption spectrometry, fluorescent X-ray analysis, NMR, etc. Specifically, for example, the resin composition or the molded product is frozen and crushed, and the dissolved substance dissolved in chloroform is measured and detected by NMR.

[0053] (monoalkylphosphinic acid)

[0054] The monoalkylphosphinic acid functions as a flame retardant. It is presumed that the monoalkylphosphinic acid is likely to exist near the surface of the molded article, effectively exhibits a free radical capture effect in the gas phase, and exhibits flame retardancy. The monoalkylphosphinic acid may include a compound represented by the following formula.

[0055] [Chemical formula 2]

[0056]

[0057] R may be an alkyl group having 1 to 8 carbon atoms. The monoalkylphosphinic acid is preferably monoethylphosphinic acid in which R is an ethyl group.

[0058] The content of monoalkyl phosphinic acid in the resin composition is preferably adjusted with respect to the ratio of dialkyl phosphinic acid metal salt. That is, the ratio of monoalkyl phosphinic acid to dialkyl phosphinic acid metal salt is preferably less than 20% by mass. The ratio of monoalkyl phosphinic acid to dialkyl phosphinic acid metal salt is preferably more than 1% by mass, preferably more than 5% by mass. The ratio of monoalkyl phosphinic acid to dialkyl phosphinic acid metal salt is preferably set to more than 1% by mass and less than 20% by mass, and is further preferably set to more than 5% by mass and less than 20% by mass. When the ratio of monoalkyl phosphinic acid to dialkyl phosphinic acid metal salt is less than 1% by mass, flame retardancy is reduced. In addition, even if the ratio of monoalkyl phosphinic acid to dialkyl phosphinic acid metal salt is more than 20% by mass, flame retardancy is also reduced. It is speculated that this is because, in the heated state during the mixing of the resin composition, the dialkyl phosphinic acid metal salt reacts with the monoalkyl phosphinic acid, and the dialkyl phosphinic acid metal salt is decomposed.

[0059] In addition, the ratio of the monoalkylphosphinic acid to the resin composition may be, for example, 0.1 mass % or more and 3 mass % or less.

[0060] The detection method of monoalkylphosphinic acid is not particularly limited. Monoalkylphosphinic acid can be detected by a known method. For example, monoalkylphosphinic acid can be detected by combining ion chromatography, capillary electrophoresis, ICP-AES (high-frequency inductively coupled plasma emission spectrometry), ICP-MS (inductively coupled plasma mass spectrometry), atomic absorption spectrometry, fluorescent X-ray analysis, NMR, etc. Specifically, for example, the resin composition or the molded product is frozen and crushed, and the dissolved substance dissolved in chloroform is measured and detected by NMR.

[0061] (Other ingredients)

[0062] The resin composition may include other components within the scope of not damaging the effect of the present invention. As other components, other flame retardants, fillers, impact modifiers, crystal nucleating agents, antioxidants, light stabilizers, antistatic agents, lubricating materials, plasticizers, pigments, dyes, etc. other than the flame retardant may be cited. In addition, the resin composition may include components known as additives. Below, they are described respectively.

[0063] <Other flame retardants>

[0064] 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 polysiloxane-based flame retardants. Other flame retardants may be used alone or in combination of two or more.

[0065] <Filling Agent>

[0066] Fillers are roughly divided into organic fillers and inorganic fillers. Examples of organic fillers include polymers of natural origin such as starch, cellulose particles, cellulose fibers, wood powder, bean curd residues, rice husks, wheat bran, and their modified products. In addition, high-melting-point organic fibrous substances such as polyamides, fluororesins, and acrylic resins can also be used.

[0067] As the inorganic filler, a fibrous, powdery or plate-like filler can be used. Examples of fibrous fillers include glass fibers, carbon fibers, silica fibers, silica·alumina fibers, zirconium oxide fibers, boron nitride fibers, silicon nitride fibers, boron fibers, potassium titanate fibers, wollastonite, barium sulfate fibers, and fibrous materials of metals such as stainless steel, aluminum, titanium, copper, and brass.

[0068] Examples of powdery fillers include carbon black, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay, diatomaceous earth, metal oxides such as iron oxide, titanium oxide, aluminum oxide, metal carbonates such as calcium carbonate, magnesium carbonate, metal sulfates such as calcium sulfate, barium sulfate, and silicon carbide, silicon nitride, boron nitride, and various metal powders. Examples of plate-like inorganic fillers include mica, glass flakes, layered silicates, and various metal foils. The filler can be used alone or in combination of two or more.

[0069] <Impact modifier>

[0070] The impact modifier is preferably a thermoplastic elastomer based on a constituent unit derived from olefins, such as ethylene propylene diene monomer (EPDM). In addition, the impact modifier may also be a thermoplastic elastomer, and it is particularly preferred to include a constituent unit derived from olefins. Examples of thermoplastic elastomers include methyl methacrylate-butadiene-styrene copolymers (MBS), acrylonitrile-butadiene-styrene copolymers (ABS), styrene-butadiene-styrene copolymers (SBS), styrene-ethylene·butylene-styrene block copolymers (SEBS), ethylene-octene copolymers (EOR) and butyl acrylate-methyl methacrylate copolymers. From the perspective of the compatibility and flame retardancy of the resin composition and the dispersibility of the thermoplastic elastomer in the resin composition, the impact modifier is preferably SEBS and EOR. The impact modifier may be used alone or in combination of two or more.

[0071] <Crystallization nucleating agent>

[0072] The crystal nucleating agent can use a known crystal nucleating agent. Examples of crystal nucleating agents include metal salts of carboxylic acids, dibenzyl sorbitol derivatives, and alkali metal salts of phosphoric acid. Specific examples of crystal nucleating agents include: sodium benzoate, aluminum adipate, aluminum p-tert-butylbenzoate, 1,3,2,4-dibenzylidene sorbitol, 1,3,2,4-bis(p-methyl-benzylidene) sorbitol, 1,3,2,4-bis(p-ethylbenzylidene) sorbitol, 1,3-p-chlorobenzylidene-2,4-p-methylbenzylidene) sorbitol, sodium bis(4-tert-butylphenyl) phosphate, sodium bis(4-tert-methylphenyl) phosphate, potassium bis(4,6-di-tert-butylphenyl) phosphate, sodium 2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate, sodium 2,2'-ethylidene-bis(4,6-di-tert-butylphenyl) phosphate. The crystal nucleating agents may be used alone or in combination of two or more.

[0073] <Antioxidants>

[0074] Examples of antioxidants include phenolic antioxidants, phosphorus antioxidants, and sulfur antioxidants. The antioxidant is preferably a phenolic antioxidant, and more preferably an alkyl-substituted phenolic antioxidant. The antioxidant may be used alone or in combination of two or more.

[0075] <Light Stabilizer>

[0076] Examples of the light stabilizer include benzophenone-based light stabilizers, benzotriazole-based light stabilizers, and NH-type and N-methyl-type hindered amine-based light stabilizers. The light stabilizer may be used alone or in combination of two or more.

[0077] <Antistatic Agent>

[0078] Examples of antistatic agents include: cationic antistatic agents such as fatty acid quaternary ammonium ion salts and polyamine quaternary salts (polyamine quaternary salts); anionic antistatic agents such as higher alcohol phosphate ester salts, higher alcohol EO adducts, polyethylene glycol fatty acid esters, anionic alkyl sulfonates, higher alcohol sulfate ester salts, higher alcohol ethylene oxide adduct sulfate ester salts, and higher alcohol ethylene oxide adduct phosphate ester salts; nonionic antistatic agents such as polyol fatty acid esters, polyethylene glycol phosphate esters, and polyoxyethylene alkyl allyl ethers; amphoteric antistatic agents such as amphoteric alkyl betaines such as alkyl dimethylaminoacetic acid betaine, and imidazoline type amphoteric active agents. The antistatic agent can be used alone or in combination of two or more.

[0079] <Lubricant>

[0080] 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, polysiloxane powder, methylene bis stearic acid amide, and N,N'-ethylene bis stearic acid amide. The lubricants may be used alone or in combination of two or more.

[0081] <Plasticizer>

[0082] Examples of the plasticizer include polyethylene glycol, polyamide oligomer, ethylene bis stearamide, phthalate ester, adipate ester, polystyrene oligomer, polyethylene wax, silicone oil, and mineral oil. The plasticizer may be used alone or in combination of two or more.

[0083] 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, for example, about 0.1 to 30% by mass, preferably 0.1 to 20% by mass, based on the total mass of the resin composition.

[0084] The method for producing the resin composition is not particularly limited. The resin composition can be produced, for example, by mixing and melt-kneading the components.

[0085] The melt mixing in the present embodiment is carried out using a mixing device such as a Banbury mixer, a roller, a plastograph, an extruder (single screw extruder, multi-screw extruder (e.g., a twin screw extruder), etc.) and a kneader. From the viewpoint of production efficiency, an extruder is preferably used for melt mixing. In addition, from the viewpoint of being able to impart high shear properties, a multi-screw extruder is more preferably used for melt mixing, and a twin screw extruder is particularly preferably used. Here, the term extruder is used within the scope of an extrusion mixer.

[0086] The temperature during melt kneading (melt kneading temperature) is above the melting temperature of the polyolefin resin. The melt kneading temperature is preferably 150 to 250° C., and is appropriately selected according to 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 in melt kneading, the kneading melt temperature is equivalent to the barrel temperature.

[0087] Before melt-kneading, the components may be mixed in advance (dry blending) using various mixers such as a tumbler or a high-speed mixer known as a Henschel mixer.

[0088] In the production method of the present embodiment, after the melt-kneaded product is extruded into a strand shape, the kneaded product extruded into a strand shape may be processed into a form such as a pellet or a sheet.

[0089] The resin composition of the present invention may be in various forms such as powder, granule, sheet (tablet), pellet, and flake.

[0090] The resin composition in the embodiment is molded into any shape to produce a molded article. Examples of the molding method of the molded article include injection molding, extrusion molding, blow molding, vacuum molding, profile extrusion molding, compression molding, and gas-assisted molding.

[0091] When using the resin composition in the present embodiment to manufacture injection molded products, a conventionally known injection molding machine can be used. The injection molded product can be manufactured by melting the resin composition in a barrel, 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 barrel temperature (melting temperature) of 170 to 230°C and a mold temperature of 40 to 80°C.

[0092] The shape and size of the molded article are not particularly limited and can be arbitrarily set according to the purpose of the molded article.

[0093] The molded products can be used for interior or exterior parts of electrical or electronic equipment such as home appliances, OA and media-related equipment, optical equipment and communication equipment, automobiles, machine parts, and housing and building parts. From the perspective of excellent strength, good flame retardancy, and low environmental load, the molded products can be suitably used as exterior parts (especially housings) of electrical or electronic equipment such as copiers, printers, personal computers, and televisions.

[0094] [Example]

[0095] Hereinafter, the present invention will be specifically described by showing examples, but the present invention is not limited to these examples.

[0096] [Example 1]

[0097] KTX-30 (manufactured by Kobe Steel) was used as a twin-screw kneader, and the resin was 94.2% by mass of polypropylene ("J715M" (manufactured by PRIME POLYMER) as a resin, 5% by mass of aluminum diethylphosphinate ("Exolit OP1230" (manufactured by CLARIANT) as a flame retardant, and 0.8% by mass of monoethylphosphinic acid ("JAMP-2" manufactured by Johoku Chemical Industry Co., Ltd.) were melt-kneaded at a barrel temperature of 190° C. and a screw speed of 200 rpm, thereby obtaining a resin composition of Example 1.

[0098] [Example 2]

[0099] A resin composition of Example 2 was obtained in the same manner as in Example 1 except that the amount of polypropylene, the amount of aluminum diethylphosphinate, and the amount of monoethylphosphinic acid were changed to 96.0% by mass.

[0100] [Example 3]

[0101] A resin composition of Example 3 was obtained in the same manner as in Example 1 except that the amount of polypropylene, the amount of aluminum diethylphosphinate, and the amount of monoethylphosphinic acid were changed to 97.7% by mass.

[0102] [Example 4]

[0103] A resin composition of Example 4 was obtained in the same manner as in Example 1 except that the amount of polypropylene, the amount of aluminum diethylphosphinate, and the amount of monoethylphosphinic acid were changed to 80.5% by mass, 17.5% by mass, and 2.0% by mass.

[0104] [Example 5]

[0105] A resin composition of Example 5 was obtained in the same manner as in Example 1 except that the amount of polypropylene, the amount of aluminum diethylphosphinate, and the amount of monoethylphosphinic acid were changed to 86.5% by mass, 12.5% ​​by mass, and 1.0% by mass.

[0106] [Example 6]

[0107] A resin composition of Example 6 was obtained in the same manner as in Example 1 except that the content of polypropylene, the content of aluminum diethylphosphinate, and the content of monoethylphosphinic acid were changed to 91.8% by mass, 8.0% by mass, and 0.2% by mass.

[0108] [Comparative Example 1]

[0109] A resin composition of Comparative Example 1 was obtained in the same manner as in Example 1 except that the content of polypropylene, the content of aluminum diethylphosphinate, and the content of monoethylphosphinic acid were changed to 74.9 mass %, 25.0 mass %, and 0.1 mass % respectively.

[0110] [Comparative Example 2]

[0111] 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 mass %, the content of aluminum diethylphosphinate was 0.5 mass %, and the content of monoethylphosphinic acid was 0.1 mass %.

[0112] [Comparative Example 3]

[0113] A resin composition of Comparative Example 3 was obtained in the same manner as in Example 1 except that the content of polypropylene, the content of aluminum diethylphosphinate, and the content of monoethylphosphinic acid were changed to 93.5% by mass, 4.5% by mass, and 2.0% by mass.

[0114] [Comparative Example 4]

[0115] A resin composition of Comparative Example 4 was obtained in the same manner as in Example 1 except that the content of polypropylene, the content of triphenylphosphine, and the content of monoethylphosphinic acid were changed to 96.0% by mass, 3.5% by mass, and 0.5% by mass.

[0116] [Comparative Example 5]

[0117] A resin composition of Comparative Example 5 was obtained in the same manner as in Example 1 except that the content of polypropylene, the content of aluminum diethylphosphinate, and the content of tricresyl phosphate were changed to 97.7% by mass, 2.0% by mass, and 0.3% by mass.

[0118] The compositions of the resin compositions of Example 1 to Comparative Example 5 are shown in Table 1 below.

[0119] [Table 1]

[0120]

[0121] [evaluate]

[0122] The flame retardancy test and strength test of the resin compositions of Examples 1 to 6 and Comparative Examples 1 to 5 obtained as described above were conducted as follows.

[0123] (1) Flame retardancy test

[0124] After drying the resin composition of each embodiment and each comparative example at 80°C for 4 hours, the resin composition was molded into a long strip test piece 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) at a barrel temperature of 170 to 200°C and a mold temperature of 80°C, and a flame retardancy test was performed.

[0125] The flame retardancy test was conducted as follows: the test piece was humidified in a constant temperature room at 23°C and 50% humidity for 48 hours, and then, after being stored in a constant temperature room at 70°C for 168 hours, the test piece was tested according to the well-known UL94 (UL94 combustion evaluation method) given by the Underwriters Laboratories (UL). It should be noted that in this method, the burning time (the time until the flame disappears) after the flame contacts the test piece is measured, and the flame is contacted twice. In Table 2, the burning times t1 and t2 respectively represent the first and second burning times.

[0126] The test pieces of each example and comparative example were evaluated, and the evaluation results were classified as follows.

[0127] ◎: V2 and the average burning time of the first and second times is less than 10 seconds

[0128] ○: V2 and the first burning time is more than 10 seconds and less than 20 seconds

[0129] △: V2 and the burning time is more than 20 seconds and less than 30 seconds

[0130] ×: not V (burning time is more than 30 seconds) (failed)

[0131] (2) Strength test (Charpy impact test)

[0132] After drying the particles of the resin composition of each embodiment and each comparative example at 80°C for 4 hours, an injection molding machine (ROBOSHOT S-2000i50Bp, manufactured by FANUC Corporation) was used to mold a test piece for evaluating Charpy impact strength (total length 80 mm, width 10 mm, thickness 4 mm, width of notch 8 mm) at a barrel temperature of 170 to 200°C and a mold temperature of 80°C. The obtained test piece was used to measure the Charpy impact strength according to ISO179. The Charpy impact strength was measured for 10 test pieces, and the arithmetic mean value was calculated. The following evaluation criteria are "◎" or "○" for qualified, and "×" for unqualified.

[0133] Evaluation Benchmarks

[0134] ◎:15kJ / m 2 above

[0135] ○:10kJ / m 2 Above and less than 15kJ / m 2

[0136] ×: less than 10 kJ / m 2

[0137] The evaluation results are shown in Table 2 below.

[0138] [Table 2]

[0139]

[0140] 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 dialkylphosphinic acid metal salt 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 dialkylphosphinic acid metal salt was 1% by mass or more and 20% by mass or less.

[0141] Comparing Example 2 and Comparative Example 4 in Table 1, Example 2 contains both aluminum diethylphosphinate and monoethylphosphinic acid, while Comparative Example 4 contains monoethylphosphinic acid but does not contain aluminum diethylphosphinate, and instead contains triphenylphosphine. As shown in Table 2, the flame retardancy and strength of Comparative Example 4 are low, but the flame retardancy and strength of Example 2 are high. In this way, when the resin composition contains both aluminum diethylphosphinate and monoethylphosphinic acid, the flame retardancy and strength can be improved.

[0142] Comparing Example 3 and Comparative Example 5 in Table 1, Example 3 contains both aluminum diethylphosphinate and monoethylphosphinic acid, while Comparative Example 5 contains aluminum diethylphosphinate but does not contain monoethylphosphinic acid, but contains tricresyl phosphate instead. As shown in Table 2, the flame retardancy and strength of Comparative Example 5 are low, but the flame retardancy and strength of Example 3 are high. In this way, when the resin composition contains both aluminum diethylphosphinate and monoethylphosphinic acid, the flame retardancy and strength can be improved.

[0143] As can be known from described embodiment 2,3, comparative example 4,5, when resin combination comprises both diethyl phosphinate aluminum and monoethyl phosphinic acid, flame retardancy and intensity can be improved.It is inferred that this is because there is a certain interaction between diethyl phosphinate aluminum and monoethyl phosphinic acid that improves flame retardancy and intensity.Specifically, as mentioned above, it is inferred that the monoethyl phosphinic acid as low molecular weight gathers near the surface of the molded article and promotes the free radical capture effect in the gas phase.

[0144] Although aluminum diethylphosphinate and monoethylphosphinic acid were contained in Comparative Example 1, the strength was reduced. This is because the ratio of aluminum diethylphosphinate to the resin composition in Comparative Example 1 was as high as 25% by mass.

[0145] Although aluminum diethylphosphinate and monoethylphosphinic acid were contained in Comparative Example 2, the flame retardancy was reduced. This is because, in Comparative Example 2, the ratio of aluminum diethylphosphinate to the resin composition was as low as 0.5 mass %.

[0146] Comparing Example 1 with Comparative Example 3, although both contain aluminum diethylphosphinate and monoethylphosphinic acid, the flame retardancy is reduced in Comparative Example 3. This is presumably because in Comparative Example 3, the ratio of monoethylphosphinic acid to the metal salt of diethylphosphinic acid is as high as more than 20%, and aluminum diethylphosphinate is decomposed by monoethylphosphinic acid.

[0147] Furthermore, Examples 1 to 3 in which the proportion of aluminum diethylphosphinate was 2 mass % or more and 5 mass % or less had higher strength than Examples 4 to 6 in which the proportion of aluminum diethylphosphinate exceeded 5 mass %.

[0148] Industrial Applicability

[0149] The resin composition of the present invention is useful for molding parts requiring flame retardancy and strength.

Claims

1. A resin composition comprising a polyolefin, a dialkylphosphinic acid metal salt and a monoalkylphosphinic acid, wherein: The ratio of the dialkylphosphinate 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 mass % or more and 20 mass % or less.

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

3. The resin composition according to claim 1 or 2, wherein The ratio of the monoalkylphosphinic acid to the dialkylphosphinic acid metal salt is 5 mass % or more and 20 mass % or less.

4. The resin composition according to any one of claims 1 to 3, wherein The polyolefin is polypropylene.

5. The resin composition according to any one of claims 1 to 4, wherein The dialkylphosphinate metal salt is aluminum diethylphosphinate.

6. The resin composition according to any one of claims 1 to 5, wherein The monoalkylphosphinic acid is monoethylphosphinic acid. 7 . A molded article formed from the resin composition according to claim 1 .

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

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

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