Resin composition and molded article obtained by molding said resin composition

Abstract

Provided is a novel technique for improving flame retardancy of a polyolefin-based resin, a polystyrene-based resin, or a polylactic acid-based resin. The present technique provides a resin composition which comprises: one or more resins that are selected from the group consisting of polyolefin-based resins, polystyrene-based resins, and polylactic acid-based resins; aluminum hydroxide that has a weight loss start temperature of 253°C or lower; and expandable graphite that has a weight loss start temperature of 180-210°C and a heating weight loss rate at 500°C of 18.5% or more.

Description

Resin composition, and molded article obtained by molding the resin composition.

[0001] This technology relates to a resin composition. More specifically, it relates to a resin composition capable of producing flame-retardant molded articles, and to a molded article obtained by molding the resin composition.

[0002] Polycarbonate (PC) resin / acrylonitrile-butadiene-styrene copolymer (ABS) resin, which offers an excellent balance of physical properties such as flame retardancy, rigidity, heat resistance, and strength, is commonly used in electrical appliances, photocopiers, and vehicle parts. Although these resins have an excellent balance of physical properties, they are expensive, so there is a desire to use other, less expensive resins. However, other resins have the problem of inferior flame retardancy.

[0003] Against this backdrop, the development of technologies to improve the flame retardancy of resins is progressing. For example, Patent Document 1 proposes a technology that achieves good flame retardancy without using halogen-based or phosphorus-based flame retardants by filling a substrate mainly composed of ethylene vinyl acetate copolymer with expanded graphite having an expansion start temperature of 200°C to 300°C and aluminum hydroxide.

[0004] Patent Document 2 proposes a technology to improve the fire resistance and flame retardancy of polyurethane while maintaining its heat insulation, elasticity, sound insulation, etc., by incorporating a flame retardant into polyurethane that contains at least ammonium polyphosphate, aluminum hydroxide or magnesium hydroxide, a polyhydric alcohol-based carbon layer forming agent, a nitrogen-containing compound having a melamine skeleton, and expanded graphite.

[0005] Patent Document 3 proposes a technique for obtaining a molded article that has good metal hydroxide incorporation, i.e., good dispersion of metal hydroxide in a flame-retardant resin composition, and an excellent balance of mechanical strength, flexibility, and flame retardancy, by using a copolymer of ethylene and a vinyl ester compound in combination with a specific propylene polymer.

[0006] Patent Document 4 proposes a thermoplastic resin composite material that exhibits flame retardant effects by utilizing the fact that the compatibility between thermoplastic resin and charcoal is extremely low, causing charcoal to appear on the surface and cover the entire material, and by impregnating the charcoal on the surface with sodium polyborate.

[0007] Patent Document 5 proposes a flame-retardant polypropylene laminate in which a polypropylene resin containing recycled polypropylene is used as an intermediate layer, and polypropylene resins mainly made from virgin polypropylene are laminated on the surface and back layers, the thickness of each layer of the laminate is set within a predetermined range, and each of the surface, intermediate, and back layers contains 13 to 17% by weight of a flame retardant.

[0008] Patent Document 6 proposes a resin composition that includes a thermoplastic resin (A), a phosphorus-based flame retardant (B), and an acid-modified polyolefin resin (C), wherein the phosphorus-based flame retardant (B) contains ammonium polyphosphate, and the proportion of the phosphorus-based flame retardant (B) is 60% by mass or more, thereby increasing the freedom of composition in flame-retardant resin products with excellent mechanical strength.

[0009] Japanese Patent Publication No. 2006-193590, Japanese Patent Publication No. 2012-52092, Japanese Patent Publication No. 2013-147586, Japanese Patent Publication No. 2008-222753, Japanese Patent Publication No. 2001-009995, Japanese Patent Publication No. 2024-163781

[0010] As mentioned above, development of technologies to improve the flame retardancy of resins is underway, but further development is still expected. For example, polypropylene and polystyrene are known to be highly flammable, with a critical oxygen index (LOI) of 18-19. To make them flame-retardant, flame retardancy has been improved by using methods such as ammonium polyphosphate (APP)-based flame retardants, bromine-based flame retardants, or phosphorus-based flame retardants such as phosphate esters.

[0011] However, ammonium polyphosphate (APP) flame retardants are expensive, brominated flame retardants have a high environmental impact, and phosphorus-based flame retardants such as phosphate esters have the problem of lowering the heat distortion temperature.

[0012] Therefore, the primary objective of this technology is to provide a novel technology that improves the flame retardancy of polyolefin resins, polystyrene resins, or polylactic acid resins.

[0013] The inventors of this invention conducted intensive research to solve the aforementioned problems and discovered that shifting the peak exothermic temperature of the resin to a lower temperature significantly improves its flame retardancy. The general technique involves adding a flame retardant to the resin, which shifts the peak exothermic temperature to a higher temperature, thereby improving its flame retardancy. However, this technology takes a different approach from conventional methods, shifting the peak exothermic temperature of the resin to a lower temperature, which promotes the decomposition of the resin in the initial stages of combustion, forming a thick carbonized layer, and consequently significantly improving the flame retardancy of the resin.

[0014] While techniques for improving flame retardancy by adding aluminum hydroxide or expandable graphite to resins are already known, these typically achieve flame retardancy by shifting the resin's exothermic peak temperature to a higher temperature. However, this technology successfully shifts the resin's exothermic peak temperature to a lower temperature by using aluminum hydroxide with a specific weight loss onset temperature and expandable graphite with a specific weight loss onset temperature and heating weight loss rate, thus completing this technology.

[0015] Specifically, this technology first provides a resin composition containing one or more resins selected from the group consisting of polyolefin resins, polystyrene resins, and polylactic acid resins; aluminum hydroxide having a weight loss onset temperature of 253°C or lower; and expandable graphite having a weight loss onset temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or higher at 500°C. In the resin composition according to this technology, the weight loss onset temperature of the aluminum hydroxide may be 20°C or more higher than the weight loss onset temperature of the expandable graphite. In the resin composition according to this technology, the content of aluminum hydroxide in the resin composition may be 5% by weight or more and 30% by weight or less. In the resin composition according to this technology, the content of expandable graphite in the resin composition may be 5% by weight or more and 20% by weight or less. In thermogravimetric differential thermal analysis (TG-DTA), the resin composition may have an exothermic peak in the region of 250°C to 325°C. The temperature at which the exothermic peak of the resin composition DTA according to this technology is observed may be 10°C or more lower than the temperature at which the exothermic peak of DTA is observed in thermogravimetric differential thermal analysis (TG-DTA). The resin composition according to this technology may contain two or more resins selected from the group consisting of polyolefin resins, polystyrene resins, and polylactic acid resins. The resin composition according to this technology may also contain polyolefin resins and polystyrene resins. In this case, the content of the polyolefin resin in the resin component may be 78 to 97% by mass. The content of the polystyrene resin in the resin component may also be 0.01 to 5% by mass. The resin composition according to this technology may also contain recycled resins. The recycled resin may include recycled polyolefin resins. The recycled polyolefin resin may include recycled polypropylene resins and / or recycled polyethylene resins. The recycled resin may also contain recycled cellulose components.In this case, the content of recycled cellulose components in the recycled resin can be set to 0.0001 to 5% by mass. Here, recycled cellulose components refer to cellulose-based materials such as paper labels attached to plastic containers or chopsticks accidentally mixed into plastic food containers. The resin composition according to this technology may contain a filler. In this case, the filler may be a biomass-derived filler. As a biomass-derived filler, one or more fillers selected from the group consisting of cellulose, lignocellulose, wood powder, and bamboo powder can be used. In the resin composition according to this technology, the content of the filler in the resin composition can be 1% by weight or more and 40% by weight or less. The resin composition according to this technology may contain a flame retardant. In this case, the flame retardant may be a phosphorus-based flame retardant. As a phosphorus-based flame retardant, a phosphate ester-based flame retardant can be used. The resin composition according to this technology can be used for one or more applications selected from electrical appliances, photocopiers, and vehicle parts. This technology then provides a molded article obtained by molding a resin composition related to this technology.

[0016] This is a conceptual diagram illustrating the mechanism by which flame retardancy is achieved in this technology. The graph shows the results of thermogravimetric differential thermal analysis (TG-DTA) in the example.

[0017] The following describes preferred embodiments for implementing this technology. The embodiments described below are examples of typical embodiments of this technology, and any combination of these embodiments is possible. Furthermore, this does not mean that the scope of this technology will be narrowed.

[0018] 1. Resin Composition The resin composition relating to this technology contains a resin, aluminum hydroxide, and expandable graphite. In addition, the resin composition relating to this technology may optionally contain fillers, flame retardants, compatibilizers, and other components that can be used in the manufacture of resin molded articles.

[0019] As mentioned above, a common technique for improving the flame retardancy of resins is to use ammonium polyphosphate (APP)-based flame retardants (hereinafter also referred to as "APP-based flame retardants"). For example, when an APP-based flame retardant is used with resins such as polypropylene, it is known that when the polypropylene burns, the APP-based flame retardant decomposes at a temperature close to the decomposition temperature of the polypropylene, forming an insulating foam layer, thereby making the polypropylene flame retardant.

[0020] On the other hand, this technology uses expandable graphite whose weight loss initiation temperature is between 180°C and 210°C, and whose heating weight loss rate at 500°C is 18.5% or more. This allows for the extraction of sulfur dioxide (SO4) from the expandable graphite at temperatures lower than the decomposition temperature of the resin. ２ As gas is generated, the expandable graphite expands, forming an insulating foam layer. Furthermore, by using aluminum hydroxide whose weight loss initiation temperature is 253°C or lower, water vapor (H) is released from the aluminum hydroxide at temperatures lower than the decomposition temperature of the resin. ２ O) is generated, and this water vapor (H ２ O) is used to dilute and cool the combustion gases. Furthermore, SO is generated from expandable graphite. ２ Gas and water vapor (H) generated from aluminum hydroxide ２ O) reacts with sulfurous acid (H ２ SO ３ Sulfonic acid gases such as ) are generated, and these sulfonic acid gases react with resin decomposition radicals to produce sulfon radicals as shown in the chemical formula (1) below. The hydrogen abstraction from the resin by the generated sulfon radicals promotes the decomposition of the resin in the initial stages of combustion, forming a char layer and leading to flame retardancy of the resin. This mechanism is shown in Figure 1.

[0021]

[0022] The following provides a detailed explanation of each component.

[0023] (1) Resin In this technology, one or more resins selected from the group consisting of polyolefin resins, polystyrene resins, and polylactic acid resins are used as the resin.

[0024] Examples of polyolefin resins that can be used in this technology include polypropylene resins, polyethylene resins, polybutene, polypentene, and copolymers of olefin monomers and monomers that can copolymerize with the olefin monomers. These can be used individually or in combination of two or more.

[0025] Examples of polystyrene resins that can be used in this technology include polystyrene, high-impact polystyrene, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-maleic anhydride copolymer, styrene-polyphenylene ether copolymer, styrene-acrylonitrile copolymer, styrene-acrylonitrile-butadiene copolymer (ABS), styrene-methylstyrene copolymer, styrene-dimethylstyrene copolymer, styrene-ethylstyrene copolymer, and styrene-diethylstyrene copolymer. These can be used individually or in combination of two or more.

[0026] Polylactic acid resins are polymers whose main component is L-lactic acid and / or D-lactic acid, and may contain other copolymer components other than lactic acid. Other monomer units include glycol compounds such as ethylene glycol, propylene glycol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, 1,4-cyclohexanedimethylol, neopentyl glycol, glycerin, pentaerythritol, bisphenol A, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; oxalic acid, adipic acid, sebacic acid, azelaic acid, dodecanedionic acid, malonic acid, glutaric acid, cyclohexanedicarboxylic acid, and terephthalic acid. Examples include acids, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, bis(p-carboxyphenyl)methane, anthracenedicarboxylic acid, 4,4'-diphenyl etherdicarboxylic acid, 5-sodium sulfisoisophthalic acid, 5-tetrabutylphosphonium isophthalic acid, and other dicarboxylic acids; glycolic acid, hydroxypropionic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxybenzoic acid, and other hydroxycarboxylic acids; and lactones such as caprolactone, valerolactone, propiolactone, undecalactone, and 1,5-oxepan-2-one.

[0027] Among these resins, examples include polystyrene resins, polylactic acid resins, and polyolefin resins. Among polyolefin resins, examples include polypropylene resins, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and alloys or copolymers containing these.

[0028] The content of one or more resins selected from the group consisting of polyolefin resins, polystyrene resins, and polylactic acid resins in the resin composition can be freely set as long as the effects and functions of the present technology are not impaired. The lower limit of the content of one or more resins selected from the group consisting of polyolefin resins, polystyrene resins, and polylactic acid resins in 100% by weight of the resin composition is, for example, 25% by weight or more, preferably 30% by weight or more, and more preferably 35% by weight or more. The upper limit of the content of one or more resins selected from the group consisting of polyolefin resins, polystyrene resins, and polylactic acid resins in 100% by weight of the resin composition is, for example, 80% by weight or less, preferably 75% by weight or less, and more preferably 70% by weight or less.

[0029] In the present technology, even when two or more resins selected from the group consisting of polyolefin resins, polystyrene resins, and polylactic acid resins are contained, excellent flame retardancy can be exhibited. As described above, in the conventional flame retardant treatment using APP-based flame retardants, it was sometimes difficult to flame retard two or more different resins. For example, in the case of a mixed resin in which different resins such as polypropylene and polystyrene are mixed, the decomposition temperatures of polypropylene and polystyrene are different, and the timing of generating combustible gas by thermal decomposition is different. Since the combustible gas is generated at a timing different from the timing when the heat insulating foam layer is formed by the decomposition of the APP-based flame retardant, it was difficult to flame retard the mixed resin.

[0030] On the other hand, in the present technology, as described above, in the temperature range lower than the decomposition temperature of the resin, SO ２ gas generated from expandable graphite reacts with water vapor (H ２ O) generated from aluminum hydroxide to generate sulfonic acid gas, and the sulfonic acid gas reacts with the decomposition radical of the resin, and hydrogen abstraction by the sulfonic radical generated by the reaction promotes the decomposition of the resin in the initial stage of combustion, and a Char layer is formed, so that the flame retardancy of the resin is exhibited. Therefore, even when two or more resins are contained, excellent flame retardancy can be exhibited.

[0031] Polyolefin resins that form a hyperconjugated structure by abstracting tertiary hydrogen present in the branched portion of the resin, polystyrene resins that form a benzylic resonance structure by abstracting tertiary hydrogen, and polylactic acid resins having a keto-enol tautomeric structure are considered to have structures that are prone to decomposition by hydrogen abstraction by sulfone radicals. It is presumed that sulfone radicals promote the decomposition at the initial stage of resin combustion by abstracting tertiary hydrogen from these resins, and achieve excellent flame retardancy by forming a char layer.

[0032] In this technology, it is preferable to use polyolefin resins and polystyrene resins in combination. As described above, in the flame retardant treatment using conventional APP-based flame retardants, when a polyolefin resin and a polystyrene resin having a lower decomposition temperature than the polyolefin resin are used in combination, decomposition gas diffuses from the polystyrene resin at a temperature lower than the temperature at which the APP-based flame retardant decomposes, making it difficult to achieve flame retardancy. On the other hand, in this technology, as described above, since flame retardancy is exhibited by a mechanism different from the flame retardant mechanism of APP-based flame retardants, excellent flame retardancy is also exhibited even when a polyolefin resin and a polystyrene resin having a lower decomposition temperature than the polyolefin resin are used in combination.

[0033] When polyolefin resins and polystyrene resins are used in combination, their contents can be freely set as long as the functions and effects of this technology are not impaired.

[0034] The lower limit of the content of the polyolefin resin in the resin component is, for example, 75% by mass or more, preferably 78% by mass or more, more preferably 80% by mass or more. The upper limit of the content of the polyolefin resin in the resin component is, for example, 97% by mass or less, preferably 96% by mass or less, more preferably 95% by mass or less, and still more preferably 94% by mass or less.

[0035] The lower limit of the content of the polystyrene resin in the resin component is, for example, 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more. The upper limit of the content of the polystyrene resin in the resin component is, for example, 5% by mass or less, preferably 3% by mass or less, more preferably 2% by mass or less.

[0036] The polyolefin resin, polystyrene resin, and polylactic acid resin used in the present technology may be recycled resins. As described above, in the present technology, since the flame retardancy is exhibited by a mechanism different from the flame retardant mechanism of the APP-based flame retardant, even a resin mixed with impurities or a mixed resin in which different resins are mixed, such as a recycled resin, exhibits excellent flame retardancy.

[0037] As the recycled resin, in the present technology, it is particularly preferable to contain a recycled polyolefin resin. The recycled polyolefin resin preferably includes a recycled polypropylene resin and / or a recycled polyethylene resin.

[0038] In the present technology, the recycled resin may contain a recycled cellulose component. For example, resins used in food containers and the like may contain components other than the resin, such as chopsticks and toothpicks. In the present technology, even when containing a cellulose component derived from wood such as chopsticks and toothpicks, excellent flame retardancy can be exhibited.

[0039] As described above, in the present technology, in a temperature range lower than the decomposition temperature of the resin, SO ２ gas generated from expandable graphite reacts with water vapor (H ２ O) generated from aluminum hydroxide to generate sulfonic acid gas, and this sulfonic acid gas reacts with the cellulose component to carbonize and form a char layer. Therefore, in the conventional technology, the cellulose component, which was considered to cause a decrease in flame retardancy, can become a component contributing to an improvement in flame retardancy in the present technology.

[0040] When containing a cellulose component, its content can be freely set as long as the functions and effects of the present technology are not impaired. The lower limit value of the content of the cellulose component in the resin component is, for example, 0.0001% by mass or more, preferably 0.001% by mass or more, more preferably 0.01% by mass or more. The upper limit value of the content of the cellulose component in the resin component is, for example, 5% by mass or less, preferably 3% by mass, more preferably 2% by mass or less.

[0041] Furthermore, this technology can also be used in combination with one or more resins selected from the group consisting of polyolefin resins, polystyrene resins, and polylactic acid resins, as long as it does not impair the function or effect of this technology.

[0042] (2) Aluminum Hydroxide The aluminum hydroxide used in this technology is characterized by having a weight loss onset temperature of 253°C or lower. In the prior art, aluminum hydroxide was used to improve flame retardancy, but in this technology, it was found that the flame retardancy effect differs depending on the weight loss onset temperature. This technology is characterized by using aluminum hydroxide with a weight loss onset temperature of 253°C or lower in combination with a specific expansive graphite described later. More specifically, even when using the specific expansive graphite described later, the flame retardancy improvement effect remains mild when used in combination with aluminum hydroxide with a weight loss onset temperature exceeding 253°C (see, for example, Comparative Example 10 described later). On the other hand, in this technology, it was found that a significant flame retardancy improvement effect is exhibited only when the specific expansive graphite described later is used in combination with aluminum hydroxide with a weight loss onset temperature of 253°C or lower.

[0043] The effects of this technology can be achieved if the weight loss initiation temperature of aluminum hydroxide is 253°C or lower, but preferably 250°C or lower, and more preferably less than 250°C. By using aluminum hydroxide with an upper limit of the weight loss initiation temperature in this range, flame retardancy can be further improved. The lower limit of the weight loss initiation temperature of aluminum hydroxide is not particularly limited as long as it does not impair the effects of this technology, but for example, it is 235°C or higher, preferably 240°C or higher.

[0044] The temperature at which the weight loss of aluminum hydroxide begins is preferably higher than the weight loss of expandable graphite, which will be described later, more preferably 20°C or more higher, even more preferably 30°C or more higher, and particularly preferably 37°C or more higher. That is, in thermogravimetric analysis (TG), it is preferable that the weight loss of aluminum hydroxide begins later than that of expandable graphite, which will be described later, preferably 20°C or more later, more preferably 30°C or more later, and particularly preferably 37°C or more later.

[0045] The content of aluminum hydroxide in the resin composition with a weight loss onset temperature of 253°C or lower can be freely set as long as it does not impair the function and effects of this technology. The lower limit of the content of aluminum hydroxide with a weight loss onset temperature of 253°C or lower in 100% by weight of the resin composition is, for example, 5% by weight or more, preferably 8% by weight or more, and more preferably 10% by weight or more. By setting the lower limit of the content of aluminum hydroxide with a weight loss onset temperature of 253°C or lower in 100% by weight of the resin composition within this range, flame retardancy can be further improved. The upper limit of the content of aluminum hydroxide with a weight loss onset temperature of 253°C or lower in 100% by weight of the resin composition is, for example, 35% by weight or less, preferably 30% by weight or less, and more preferably 25% by weight or less.

[0046] Furthermore, this technology can also be used with aluminum hydroxide other than aluminum hydroxide with a weight loss initiation temperature of 253°C or lower, as long as it does not impair the function or effect of this technology.

[0047] (3) Expandable graphite The expandable graphite used in this technology is characterized by having a weight loss initiation temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or more at 500°C. Although expandable graphite has been used in conventional technologies to improve flame retardancy, this technology has found that the flame retardancy effect differs depending on the weight loss initiation temperature and the heating weight loss rate. This technology is characterized by using expandable graphite having a weight loss initiation temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or more at 500°C in combination with the aforementioned specific aluminum hydroxide. Specifically, even when using the aforementioned specific aluminum hydroxide, if the weight loss onset temperature is outside the range of 180°C to 210°C and the weight loss rate at 500°C is less than 18.5% when used in combination with expandable graphite, the flame retardancy improvement effect remains mild (see Comparative Example 5 described later, for example). Furthermore, even if the weight loss onset temperature is 180°C to 210°C, if used in combination with expandable graphite, if the weight loss rate at 500°C is less than 18.5%, the flame retardancy improvement effect remains mild (see Comparative Example 6 described later, for example). Moreover, even if the weight loss rate at 500°C is 18.5% or more, if used in combination with expandable graphite, if the weight loss onset temperature is outside the range of 180°C to 210°C, the flame retardancy improvement effect remains mild. On the other hand, this technology found that a significant improvement in flame retardancy is achieved only when an expandable graphite having a weight loss initiation temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or more at 500°C is used in combination with the aforementioned specific aluminum hydroxide.

[0048] The effects of this technology can be achieved if the weight loss rate of the expandable graphite at 500°C is 18.5% or more, preferably 19.0% or more, and more preferably 20.0% or more. By using aluminum hydroxide with a lower limit of weight loss rate at 500°C within this range, flame retardancy can be further improved. The upper limit of the weight loss rate of the expandable graphite at 500°C is not particularly limited as long as it does not impair the effects of this technology, but is, for example, 30% or less, preferably 25% or less.

[0049] The amount of expandable graphite in the resin composition that has a weight loss initiation temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or more at 500°C can be freely set as long as it does not impair the function and effects of this technology. The lower limit of the amount of expandable graphite in 100% by weight of the resin composition that has a weight loss initiation temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or more at 500°C is, for example, 5% by weight or more, preferably 8% by weight or more, and more preferably 10% by weight or more. By setting the lower limit of the amount of expandable graphite in 100% by weight of the resin composition that has a weight loss initiation temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or more at 500°C to this range, flame retardancy can be further improved. The upper limit for the content of expandable graphite in 100% by weight of the resin composition, which has a weight loss initiation temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or more at 500°C, is, for example, 25% by weight or less, preferably 20% by weight or less, and more preferably 15% by weight or less.

[0050] Furthermore, this technology can also be used in combination with other types of expandable graphite, such as those with a weight loss initiation temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or more at 500°C, as long as it does not impair the function or effect of this technology.

[0051] (4) Fillers Fillers may be used in this technology. Fillers are not an essential component in this technology, but by using fillers, a thick char layer can be formed during combustion, and as a result, flame retardancy can be further improved.

[0052] More specifically, as mentioned above, this technology generates SO2 from expandable graphite at a temperature range lower than the decomposition temperature of the resin. ２ Gas and water vapor (H) generated from aluminum hydroxide ２ O) reacts with the other substance to generate sulfonic acid gas, and this sulfonic acid gas reacts with the filler to form a char layer, further improving flame retardancy.

[0053] As fillers that can be used in this technology, one or more fillers that can be used in general resin compositions can be freely used in combination, as long as they do not impair the function or effect of this technology.

[0054] In this technology, from the viewpoint of environmental sustainability, it is preferable to use biomass-derived fillers. Examples of biomass-derived fillers include plant-derived fillers and inorganic fillers. Examples of plant-derived fillers include one or more plant-derived fillers selected from the group consisting of wood, pulp, bamboo, sugarcane, Eucommia ulmoides, rice husks, and rice (starch), and specifically include cellulose, lignocellulose, pulp, wood flour, and bamboo flour.

[0055] The amount of filler in the resin composition can be freely set as long as it does not impair the function and effects of this technology. The lower limit of the filler content in 100% by weight of the resin composition is, for example, 1% by weight or more, preferably 5% by weight or more, and more preferably 10% by weight or more. By setting the lower limit of the filler content in 100% by weight of the resin composition within this range, flame retardancy can be further improved. The upper limit of the filler content in 100% by weight of the resin composition is, for example, 50% by weight or less, preferably 45% by weight or less, and more preferably 40% by weight or less.

[0056] (5) Flame retardants Flame retardants may be used in this technology. Although flame retardants are not an essential component in this technology, using them can further improve the flame retardancy of the resin.

[0057] As long as the function and effects of this technology are not impaired, one or more flame retardants that can be used in general resin compositions may be freely used. Examples of flame retardants that can be used in this technology include phosphorus-based flame retardants, halogen-based flame retardants, metal salt-based flame retardants, silicone-based flame retardants, fluorine-based flame retardants, and metal hydrate-based flame retardants.

[0058] Among these, the use of phosphorus-based flame retardants is preferred in this technology. Examples of phosphorus-based flame retardants include phosphate ester-based flame retardants, organophosphazene-based flame retardants, polyphosphate-based flame retardants, and red phosphorus-based flame retardants. Among these, the use of phosphate ester-based flame retardants is preferred in this technology.

[0059] The amount of flame retardant in the resin composition can be freely set as long as it does not impair the function and effects of this technology. The lower limit of the amount of flame retardant in 100% by weight of the resin composition is, for example, 0% by weight, preferably 1% by weight or more, and more preferably 5% by weight or more. By setting the lower limit of the amount of flame retardant in 100% by weight of the resin composition within this range, flame retardancy can be further improved. The upper limit of the amount of flame retardant in 100% by weight of the resin composition is, for example, 20% by weight or less, preferably 15% by weight or less, and more preferably 10% by weight or less. By setting the upper limit of the amount of flame retardant in 100% by weight of the resin composition within this range, a decrease in heat resistance can be prevented, and the bleed-out of the flame retardant to the surface of the molded product can be suppressed.

[0060] (6) Other components The resin composition relating to this technology may be used as other components by freely selecting one or more of the various components that can be used in a resin composition, depending on the purpose, as long as they do not impair the action or effect of this technology.

[0061] Other components that can be used in the resin composition relating to this technology include, for example, compatibilizers, stabilizers, plasticizers, colorants, antioxidants, dispersants, UV absorbers, lubricants, and light stabilizers.

[0062] (7) Exothermic peak temperature of the resin composition The resin composition relating to this technology preferably has an exothermic peak in thermogravimetric differential thermal analysis (TG-DTA) in the region of 250°C to 325°C. As described above, by shifting the exothermic peak temperature to a lower temperature than the exothermic peak temperature of the base resin used, decomposition in the initial stages of combustion is promoted, a char layer is formed, and as a result the flame retardancy of the resin composition is significantly improved.

[0063] In other words, as mentioned above, this technology generates SO2 from expandable graphite at a temperature range lower than the decomposition temperature of the resin. ２ Gas and water vapor (H) generated from aluminum hydroxide ２ O) reacts with sulfonic acid gas, and the reaction of this sulfonic acid gas with resin decomposition radicals generates sulfonate radicals that extract hydrogen, thereby promoting the decomposition of the resin in the initial stages of combustion. This allows the exothermic peak temperature of the resin composition to be shifted to a lower temperature than the exothermic peak temperature of the base resin used.

[0064] The exothermic peak temperature of the resin composition relating to this technology is not limited to being in the range of 250°C to 325°C; the flame-retardant effect of this technology can be fully demonstrated as long as the exothermic peak is in a temperature range lower than the inventive peak temperature of the resin used.

[0065] Specifically, in thermogravimetric differential thermal analysis (TG-DTA), the temperature at which the resin composition exhibits its exothermic peak in DTA is preferably 10°C or more lower, more preferably 15°C or more lower, and even more preferably 20°C or more lower than the temperature at which the resin used exhibits its exothermic peak in DTA.

[0066] Furthermore, the lower limit of the exothermic peak temperature in thermogravimetric differential thermal analysis (TG-DTA) of the resin composition relating to this technology can be freely set as long as it does not impair the flame retardant effect of this technology. However, since there is a concern that the flame retardancy may decrease if the exothermic peak temperature is too low, it is preferable to set it to 230°C or higher, more preferably 240°C or higher, and even more preferably 250°C or higher.

[0067] In this technology, the temperature at which the DTA of the resin composition exhibits its exothermic peak is the value measured by the method described in the examples below.

[0068] (8) Uses of the resin composition The uses of the resin composition relating to this technology are not particularly limited, but it can be suitably used in applications where flame retardancy is expected, such as for electrical appliances, photocopiers, and vehicle parts. Examples of electrical appliances include electrical and electronic equipment, office automation equipment, information terminal equipment, machine parts, home appliances, lighting equipment, and parts used therein. Examples of vehicle parts include battery housings for electric vehicles.

[0069] (9) Form of the resin composition The form of the resin composition relating to this technology is not particularly limited and can be distributed in various forms depending on the purpose and application. Examples include pellets, powders, plates, blocks, etc.

[0070] 2. Method for producing resin compositions and molded articles formed from resin compositions The resin compositions and molded articles formed from said resin compositions are characterized by the raw materials used and their physical properties, and the method for producing them is not particularly limited. For example, known methods for producing resins can be suitably used, such as a method in which raw materials are premixed using various mixers such as tumblers, Henschel mixers, and super mixers, and then melt-kneaded using mixers such as Banbury mixers, rolls, bravenders, single-screw extruders, twin-screw extruders, and kneaders.

[0071] Furthermore, for example, the product can be manufactured by supplying the components to an extruder using a feeder and melt-kneading them together, either without pre-mixing each component or by pre-mixing only some of the components. Alternatively, the resin composition obtained by pre-mixing some of the components and supplying it to an extruder for melt-kneading can be used as a masterbatch, and this masterbatch can be mixed again with the remaining components and melt-kneaded to produce the product.

[0072] Furthermore, when mixing components that are difficult to disperse, the dispersibility can be improved by, for example, dissolving or dispersing the difficult-to-disperse components in a solvent such as water or an organic solvent beforehand, and then kneading the solution or dispersion with them. After pre-mixing each component using this method, a suitable resin can be produced by melt-kneading using a mixer such as a Banbury mixer, roll, Brabender, single-screw compounding extruder, twin-screw compounding extruder, or kneader.

[0073] The molding method is not particularly limited, and any molding method commonly used for molding resins can be used. Examples of molding methods include injection molding, ultra-high-speed injection molding, injection compression molding, two-color molding, hollow molding methods such as gas-assisted molding, molding using insulated molds, molding using rapidly heated molds, foam molding (including supercritical fluids), insert molding, IMC (in-mold coating) molding, extrusion molding, sheet molding, thermoforming, rotational molding, lamination molding, and press molding. Molding methods using a hot runner system can also be used.

[0074] The present technology may also take the following configurations: [1] A resin composition comprising: one or more resins selected from the group consisting of polyolefin resins, polystyrene resins, and polylactic acid resins; aluminum hydroxide having a weight loss onset temperature of 253°C or lower; and expandable graphite having a weight loss onset temperature of 180°C or higher and a heating weight loss rate of 18.5% or higher at 500°C. [2] The resin composition according to [1], wherein the weight loss onset temperature of the aluminum hydroxide is 20°C or higher than the weight loss onset temperature of the expandable graphite. [3] The resin composition according to [1] or [2], wherein the content of aluminum hydroxide in the resin composition is 5% by weight or higher and 30% by weight or lower. [4] The resin composition according to any one of [1] to [3], wherein the content of expandable graphite in the resin composition is 5% by weight or higher and 20% by weight or lower. [5] A resin composition according to any one of [1] to [4], wherein in thermogravimetric differential thermal analysis (TG-DTA), the exothermic peak of the DTA is in the region of 250°C to 325°C. [6] A resin composition according to any one of [1] to [5], wherein in thermogravimetric differential thermal analysis (TG-DTA), the temperature at which the exothermic peak of the DTA of the resin composition is observed is 10°C or more lower than the temperature at which the resin exhibits the exothermic peak of the DTA. [7] A resin composition according to any one of [1] to [6], comprising two or more resins selected from the group consisting of polyolefin resins, polystyrene resins, and polylactic acid resins. [8] A resin composition according to [7], comprising a polyolefin resin and a polystyrene resin. [9] A resin composition according to [8], wherein the content of the polyolefin resin in the resin component is 78 to 97% by mass, and the content of the polystyrene resin in the resin component is 0.01 to 5% by mass.

[10] The resin composition according to any one of [1] to [9], wherein the resin comprises a recycled resin.

[11] The resin composition according to

[10] , wherein the recycled resin comprises a recycled polyolefin resin.

[12] The resin composition according to

[11] , wherein the recycled polyolefin resin comprises a recycled polypropylene resin and / or a recycled polyethylene resin.

[13] The resin composition according to any one of

[10] to

[12] , wherein the recycled resin contains recycled cellulose components.

[14] The resin composition according to

[13] , wherein the content of recycled cellulose components in the recycled resin is 0.0001 to 5% by mass.

[15] The resin composition according to any one of [1] to

[14] , which contains a filler.

[16] The resin composition according to

[15] , wherein the filler is a biomass-derived filler.

[17] The resin composition according to

[16] , wherein the filler is one or more fillers selected from the group consisting of cellulose, lignocellulose, pulp, wood flour, and bamboo flour.

[18] The resin composition according to any one of

[15] to

[17] , wherein the content of the filler in the resin composition is 1% by weight or more and 40% by weight or less.

[19] The resin composition according to any one of [1] to

[18] , which contains a flame retardant.

[20] The resin composition according to

[19] , wherein the flame retardant is a phosphorus-based flame retardant.

[21] The resin composition according to

[20] , wherein the phosphorus-based flame retardant is a phosphorus ester-based flame retardant.

[22] The resin composition according to any one of [1] to

[21] , wherein one or more are selected from electrical appliances, photocopiers, and vehicle parts.

[23] A molded article obtained by molding the resin composition according to any one of [1] to

[22] .

[0075] The present technology will be described in more detail below based on the following examples. The examples described below are representative examples of the present technology and should not be interpreted as narrowing the scope of the present technology.

[0076] <Experimental Example 1> 1. Raw Materials [Resin] (1) Polypropylene: Nippon Polypropylene Co., Ltd. "Wintec WSX03" (2) Polypropylene: Nippon Polypropylene Co., Ltd. "Wintec WFM-4M" (3) Polystyrene: PS Japan Co., Ltd. "GPPS HF77" (4) Polylactic acid resin: Total Energies Corbion "Luminy L105" (5) Low-density polyethylene (LDPE): Nippon Polypropylene Co., Ltd. "Novatec LD LJ803" (6) Linear low-density polyethylene (LLDPE): Nippon Polypropylene Co., Ltd. "Novatec LL UJ480" [Aluminum Hydroxide] (1) Al(OH) ３ : Fujifilm Wako Pure Chemical Industries (2) Al(OH) ３ : KC Corporation "KH-101" (3) Al(OH) ３ : Maruto Co., Ltd. "NOC-308" (4) Al(OH) ３ Nippon Light Metal Co., Ltd. "BF013" (5) Al(OH) ３ Nippon Light Metal Co., Ltd. "BF083" (6) Al(OH) ３: Nippon Light Metal Co., Ltd. "BF033" [Expandable Graphite] (1) Expandable Graphite: Air Water Performance Chemical Co., Ltd. "Mo-50N" (2) Expandable Graphite: Ito Graphite Industry Co., Ltd. "9550250" (3) Expandable Graphite: Higashi Nippon Carbon Co., Ltd. "EXP-50HO" (4) Expandable Graphite: NeoGraf Solutions, LLC "GG250-50N" (5) Expandable Graphite: Ito Graphite Industry Co., Ltd. "9280170" (6) Expandable Graphite: Higashi Nippon Carbon Co., Ltd. "EXP-80S220" (7) Expandable Graphite: Nishimura Graphite Co., Ltd. "BE-90" (8) Expandable Graphite: NeoGraf Solutions, LLC "GG280-50N" (9) Expandable Graphite: Suzuhiro Chemical Co., Ltd. "GREP-EG" (10) Expandable graphite: Air Water Performance Chemical Co., Ltd. "CA-60N" [Filler] (1) Filler: Superheated steam treated bamboo powder (Bamboo Techno Co., Ltd.) [Drip inhibitor] Drip inhibitor: Polyflon MPA FA-500H (Daikin Industries, Ltd.) [Phosphorus-based flame retardant] Phosphorus-based flame retardant: PX-202 (Daihachi Chemical Industry Co., Ltd.) [Compatibilizer] Compatibilizer: Yumex 1010 (Sanyo Chemical Industries, Ltd.)

[0077] 2. Measurement of Weight Loss Initiation Temperature and Heating Weight Loss Rate The aluminum hydroxide and expandable graphite used in this experiment were subjected to thermogravimetric analysis (TG) and differential thermal analysis (DTA) using a Thermo Plus EVO TG8120 manufactured by Rigaku Corporation.

[0078] Each of the compositional raw materials shown in Tables 1 to 3 below was placed in a quartz glass container on the sample side at approximately 2 to 5 mg, and an amount of aluminum oxide (alumina) powder, approximately the same as the sample, was placed on the reference side for measurement. The heating program involved raising the temperature from room temperature to 600°C at a rate of 10°C / min, and then lowering it at a rate of 40°C / min to measure TG and DTA. The measurement atmosphere was 200 mL / min of dry air. The aluminum hydroxide, expandable graphite, and resin composition decomposed at approximately 600°C, and weight loss stopped. Since there was no change in weight or DTA even if heating was continued thereafter, the temperature was raised to 600°C. In particular, when measuring the weight loss of expandable graphite, the weight loss at 500°C was used as the standard because sufficient weight loss was observed at 500°C. Furthermore, when performing TG-DTA measurements on expandable graphite alone, a phenomenon was sometimes observed where some of the expandable graphite would burst out of the system during measurement due to its rapid expansion. In such cases, an inverted aluminum container was cut vertically and fitted as a lid onto a quartz glass container, and two tiny holes of about 0.3 mm were drilled in the aluminum to ensure accurate measurement. This method suppressed unnatural weight loss caused by spillage due to the expansion of expandable graphite and resin compositions.

[0079]

[0080] 3. Resin Sheet Manufacturing Approximately 100 to 300 g of each composition raw material shown in Tables 2 and 3 was prepared by blending them in the weight ratios shown in Tables 2 and 3. This mixture was then kneaded and extruded using a twin-screw extruder, and the resulting strand was obtained as pellets of several millimeters using a pelletizer. The twin-screw extruder used was a Laboplast Mill Micro (2D15W, L / D=17, L-256 mm) manufactured by Toyo Seiki Seisakusho Co., Ltd. The above mixture was fed from the hopper over a period of 10 to 30 minutes using a quantitative feeder (model: F3, manufactured by Toyo Seiki Seisakusho Co., Ltd.). The barrel temperature of the extruder was set to 165 to 180°C for the die head, and the temperature below the hopper was set to 130 to 180°C depending on the base resin being kneaded. The rotation speed of the extruder screw was set in the range of 6 to 17 rpm to prevent the torque from becoming too high, especially depending on the viscosity of the base resin. The resulting strands were pelletized using a pelletizer manufactured by Toyo Seiki Seisakusho Co., Ltd.

[0081] A Kapton film was placed on a 2 mm thick steel plate, and a 120 mm x 120 mm x 2 mm thick mold was placed on top of it. 30-40 g of the above pellets were evenly packed into the mold frame, and then sandwiched between the Kapton film and the 2 mm thick steel plate. In this state, the mold was lightly clamped between two presses (Tester Industries Co., Ltd. "SA-303") heated to 180°C on both sides, preheated for approximately 5 minutes, and then pressurized to 30 MPa and left to stand for about 3 minutes. Since the pressure may drop if the resin overflows from the mold, the pressure was adjusted as needed to maintain 30 MPa for 3 minutes. After that, the resin sheet sandwiched between the steel plates was removed from the press and clamped from above and below with aluminum cooling ingots, and a 5 kg weight was placed on top to continue cooling, thereby obtaining the resin sheets for each example and each comparative example.

[0082] 4. Measurement of the Limiting Oxygen Index (LOI) Strip-shaped test pieces measuring 120 mm x 13 mm x 2 mm thick were cut from the manufactured resin sheet using a tabletop cutter (diamond cutter) from Maruto Manufacturing Co., Ltd., and the limiting oxygen index (LOI) was measured using a flammability tester (Suga Test Instruments Co., Ltd. "ON-1"). It is known that the higher this value, the higher the flame retardancy, and it is empirically known that, for example, an LOI of 28 or higher is likely to meet the V-0 (2 mm thickness) standard for flame retardancy in the UL94V test.

[0083] 5. Results are shown in Tables 2 and 3 below. Furthermore, the results of thermogravimetric differential thermal analysis (TG-DTA) for Example 1, Comparative Examples 1 and 2, Reference Example 1 shown in Table 1, and Example 3 shown in Table 2 are shown in the graph in Figure 2.

[0084]

[0085]

[0086] 6. Discussion As shown in the graph in Figure 2, the exothermic peak temperature of Comparative Example 1, in which only aluminum hydroxide with a weight loss onset temperature of 253°C or lower was added to the resin, was shifted to a higher temperature compared to Reference Example 1, which used only the resin. Furthermore, the exothermic peak temperature of Comparative Example 2, in which only expandable graphite with a weight loss onset temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or higher at 500°C was added to the resin, was also shifted to a higher temperature compared to Reference Example 1, which used only the resin.

[0087] On the other hand, compared to the exothermic peak temperature of Reference Example 1, which used only the resin, the exothermic peak temperatures of Examples 1 and 3, in which both aluminum hydroxide with a weight loss onset temperature of 253°C or lower and expandable graphite with a weight loss onset temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or higher at 500°C were added to the resin, were shifted to lower temperatures.

[0088] As shown in Table 2, Examples 2 to 19, which used aluminum hydroxide with a weight loss onset temperature of 253°C or lower, and expandable graphite with a weight loss onset temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or higher at 500°C, all showed a critical oxygen index (LOI) of 28 or higher.

[0089] On the other hand, as shown in Table 3, Comparative Examples 3 to 25, which did not use aluminum hydroxide with a weight loss onset temperature of 253°C or lower, or expandable graphite with a weight loss onset temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or higher at 500°C, had a critical oxygen index (LOI) of less than 28. More specifically, as shown in Comparative Example 9, even when expandable graphite with a weight loss onset temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or higher at 500°C was used, the flame retardancy improvement effect remained mild when used in combination with aluminum hydroxide with a weight loss onset temperature exceeding 253°C. Furthermore, as shown in Comparative Example 5, even when aluminum hydroxide with a weight loss initiation temperature of 253°C or lower was used, when it was used in combination with expandable graphite whose weight loss initiation temperature was outside the range of 180°C to 210°C and whose heating weight loss rate at 500°C was less than 18.5%, the flame retardancy improvement effect remained mild. Moreover, as shown in Comparative Example 6, even with expandable graphite whose weight loss initiation temperature was between 180°C and 210°C, when expandable graphite with a heating weight loss rate of less than 18.5% at 500°C was used in combination with aluminum hydroxide with a weight loss initiation temperature of 253°C or lower, the flame retardancy improvement effect remained mild. In addition, as shown in Comparative Examples 7, 8, and 25, even with expandable graphite exhibiting a heating weight loss rate of 18.5% or more at 500°C, when expandable graphite with a weight loss onset temperature outside the range of 180°C to 210°C was used in combination with aluminum hydroxide having a weight loss onset temperature of 253°C or lower, the flame retardancy improvement effect remained only slight.

[0090] As shown in Reference Examples 2-4 of Table 3, it is sometimes possible to improve the critical oxygen index (LOI) to 28 or higher by using phosphorus-based flame retardants. However, as shown in Comparative Examples 21, 23, and 24, in cases where neither aluminum hydroxide with a weight loss onset temperature of 253°C or lower, nor expandable graphite with a weight loss onset temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or higher at 500°C is used, an improvement in the critical oxygen index (LOI) cannot be confirmed even when phosphorus-based flame retardants are added.

[0091] <Experimental Example 2> 1. Raw Materials The raw materials used in Experimental Example 2 are listed below. Except for those listed below, the same raw materials as in Experimental Example 1 were used. [Resins] (7) High-density polyethylene (HDPE): Tosoh Corporation "Nipolon Hard 1000" (8) Recycled polypropylene (recycled PP): Green Cycle Systems Co., Ltd. "GC-P4ST00" (9) Recycled polypropylene derived from the Container and Packaging Recycling Law (recycled PP derived from the Container and Packaging Recycling Law): Green Loop Co., Ltd. [Fillers] (2) High-purity cellulose: Rettenmeyer Japan Co., Ltd. "BE-600-30" (3) Wood powder: Rettenmeyer Japan Co., Ltd. "C100" (4) Recycled paper: Rettenmeyer Japan Co., Ltd. "FD600-30" [APP-based flame retardants] (1) APP-based flame retardant: ADEKA Corporation "ADEKA Stab FP-2200" (2) APP-based flame retardant: ADEKA Corporation "ADEKA Stab FP-2500S" (3) Ammonium polyphosphate: Suzuhiro Chemical Co., Ltd. "FCP790"

[0092] 2. Resin Sheet Manufacturing: Resin sheets were manufactured using the same method as in Experimental Example 1, with each of the compositional raw materials shown in Table 4.

[0093] 3. Measurement of the Limiting Oxygen Index (LOI) The manufacturing resin sheet was measured using the same method as in Experimental Example 1.

[0094] 4. Results The results are shown in Table 4 below.

[0095]

[0096] 5. Discussion As shown in Examples 20 and 21, and Examples 22 and 23 of Table 4, it was found that when aluminum hydroxide with a weight loss onset temperature of 253°C or lower and expandable graphite with a weight loss onset temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or higher at 500°C are used, adding a filler improves the critical oxygen index (LOI). On the other hand, Comparative Example 26, which used an APP-based flame retardant without using aluminum hydroxide with a weight loss onset temperature of 253°C or lower and expandable graphite with a weight loss onset temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or higher at 500°C, had a critical oxygen index (LOI) of less than 28 due to the use of a filler.

[0097] Furthermore, comparing Example 29, which uses three different types of resins, with Comparative Example 27, Example 29, which uses an APP-based flame retardant instead of aluminum hydroxide with a weight loss onset temperature of 253°C or lower and expandable graphite with a weight loss onset temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or higher at 500°C, showed improved critical oxygen index (LOI) compared to Comparative Example 27, which uses an APP-based flame retardant instead of aluminum hydroxide with a weight loss onset temperature of 253°C or lower and expandable graphite with a weight loss onset temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or higher at 500°C. This result proves that flame retardancy can be improved even when using two or more different types of resins by using this technology.

[0098] Furthermore, as shown in Examples 25-28 and 30, when using aluminum hydroxide with a weight loss onset temperature of 253°C or lower, and expandable graphite with a weight loss onset temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or higher at 500°C, the critical oxygen index (LOI) was high, at 28 or higher, even when using two or more different resins and various fillers.

[0099] Furthermore, as shown in Examples 31 to 33, when using aluminum hydroxide with a weight loss onset temperature of 253°C or lower, and expandable graphite with a weight loss onset temperature of 180°C to 210°C and a heating weight loss rate of 18.5% or higher at 500°C, the limiting oxygen index (LOI) was high, at 28 or higher, even when using recycled resin. In addition, when flame retardancy was confirmed for Examples 31 and 33 using a method in accordance with the UL94 standard, it was confirmed that both conformed to the flame retardancy classes of V-0 (1.0 mmt) and 5VA (2.0 mmt).

Claims

1. A resin composition comprising: one or more resins selected from the group consisting of polyolefin resins, polystyrene resins, and polylactic acid resins; aluminum hydroxide having a weight loss onset temperature of 253°C or lower; and expandable graphite having a weight loss onset temperature of 180°C or higher and a heating weight loss rate of 18.5% or higher at 500°C.

2. The resin composition according to claim 1, wherein the weight loss initiation temperature of the aluminum hydroxide is 20°C or higher than the weight loss initiation temperature of the expandable graphite.

3. The resin composition according to claim 1, wherein the content of aluminum hydroxide in the resin composition is 5% by weight or more and 30% by weight or less.

4. The resin composition according to claim 1, wherein the content of the expandable graphite in the resin composition is 5% by weight or more and 20% by weight or less.

5. The resin composition according to claim 1, wherein, in thermogravimetric differential thermal analysis (TG-DTA), the DTA has an exothermic peak in the region of 250°C to 325°C.

6. The resin composition according to claim 1, wherein, in thermogravimetric differential thermal analysis (TG-DTA), the temperature at which the resin composition exhibits its DTA exothermic peak is 10°C or more lower than the temperature at which the resin exhibits its DTA exothermic peak.

7. The resin composition according to claim 1, comprising two or more resins selected from the group consisting of polyolefin resins, polystyrene resins, and polylactic acid resins.

8. The resin composition according to claim 7, comprising a polyolefin resin and a polystyrene resin.

9. The resin composition according to claim 8, wherein the content of the polyolefin resin in the resin component is 78 to 97% by mass, and the content of the polystyrene resin in the resin component is 0.01 to 5% by mass.

10. The resin composition according to claim 1, wherein the resin includes a recycled resin.

11. The resin composition according to claim 10, wherein the recycled resin includes a recycled polyolefin resin.

12. The resin composition according to claim 11, wherein the recycled polyolefin resin includes a recycled polypropylene resin and / or a recycled polyethylene resin.

13. The resin composition according to claim 10, wherein the recycled resin contains recycled cellulose components.

14. The resin composition according to claim 13, wherein the content of the recycled cellulose component in the recycled resin is 0.0001 to 5% by weight.

15. The resin composition according to claim 1, comprising a filler.

16. The resin composition according to claim 15, wherein the filler is a biomass-derived filler.

17. The resin composition according to claim 16, wherein the filler is one or more fillers selected from the group consisting of cellulose, lignocellulose, pulp, wood powder, and bamboo powder.

18. The resin composition according to claim 15, wherein the content of the filler in the resin composition is 1% by weight or more and 40% by weight or less.

19. The resin composition according to claim 1, comprising a flame retardant.

20. The resin composition according to claim 19, wherein the flame retardant is a phosphorus-based flame retardant.

21. The resin composition according to claim 20, wherein the phosphorus-based flame retardant is a phosphate ester-based flame retardant.

22. The resin composition according to claim 1, wherein one or more are selected from electrical appliances, photocopiers, and vehicle parts.

23. A molded article obtained by molding the resin composition described in claim 1.

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