Flame-retardant resin composition, molded product using same, and method for producing flame-retardant resin composition and molded product
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Filing Date
- 2026-03-23
- Publication Date
- 2026-06-30
Abstract
Description
Flame-retardant resin composition, molded article using the same, and method for manufacturing the flame-retardant resin composition and molded article
[0001] The present disclosure relates to a flame-retardant resin composition, a molded article using the same, and a method for producing the flame-retardant resin composition and the molded article.
[0002] Molded articles of thermoplastic resin compositions based on polyolefin resins, polystyrene resins, polycarbonate resins, etc. are used for housings and parts of home appliances and office automation equipment such as copiers and computers. Examples of thermoplastic resins include polyolefin resins such as polypropylene (abbreviated as PP) resin and polyethylene (abbreviated as PE) resin, polystyrene resins such as high impact polystyrene (abbreviated as HIPS) resin and general purpose polystyrene (abbreviated as GPPS) resin, and acrylonitrile resins such as acrylonitrile-butadiene-styrene (abbreviated as ABS) resin and acrylonitrile-styrene (abbreviated as AS) resin. Most of the thermoplastic resins used for the housings and parts of office automation equipment are acrylonitrile-based resins (e.g., ABS resin, AS resin), polycarbonate (PC)-based resins, polycarbonate / acrylonitrile-based resins, or flame-retardant resins.
[0003] Because polyolefins are flammable, they are required to be flame-retardant when used in automobile parts, home appliances, building materials, etc. It is known to incorporate a flame retardant into polyolefins to impart flame retardancy. For example, Patent Document 1 (Japanese Patent No. 3648032) and Patent Document 2 (Japanese Patent Laid-Open Publication No. 7-76640) disclose flame-retardant resin compositions in which PP resin is blended with a brominated flame retardant, a flame retardant assistant, hydrotalcites, etc. Patent Document 3 (International Publication No. 2014 / 017072) discloses a resin material in which a brominated flame retardant and a flame retardant assistant are blended with PP resin obtained by sorting from crushed waste home appliances. Patent Document 3 also discloses the addition of a metal deactivator to HIPS resin obtained by sorting from crushed waste home appliances.
[0004] Patent No. 3648032 Publication JP 7-76640 Publication International Publication No. 2014 / 017072
[0005] From the viewpoint of reducing environmental impact, etc., there is a demand for the recycling of resin materials recovered from waste. In order to impart flame retardancy to recycled polypropylene resin, which is recycled PP resin, a brominated flame retardant and a flame retardant aid are added to the recycled polypropylene resin, and various additives are further added to the melt-kneaded mixture, which is then molded, but this sometimes results in discoloration of the molded product.
[0006] An object of the present disclosure is to provide a flame-retardant resin composition that can suppress discoloration of molded articles.
[0007] The flame-retardant resin composition of the present disclosure comprises 40 to 90 wt% recycled polypropylene resin (A), 1 to 25 wt% bromine-based flame retardant (B), 1 to 15 wt% antimony compounds (C), 0.1 to 10 wt% hydrotalcites (D), 0.01 to 3 wt% triazine compounds (E), 0.01 to 3 wt% sulfur-based antioxidant (F), and 0.01 to 3 wt% phosphorus-based antioxidant (G). The bromine-based flame retardant (B) includes at least one of 2,2-bis[3,5-dibromo-4-(2,3-dibromopropoxy)phenyl]propane and bis[3,5-dibromo-4-(2,3-dibromopropoxy)phenyl]sulfone. The phosphorus-based antioxidant (G) is a diphosphite-based compound.
[0008] The molded article of the present disclosure is a molded article formed using the flame-retardant resin composition of the present disclosure.
[0009] According to the flame-retardant resin composition of the present disclosure, a molded article with reduced discoloration can be obtained.
[0010] In this specification, a numerical range such as "x to y" includes the upper and lower limits unless otherwise specified, and represents a numerical range of "not less than x and not more than y."
[0011] Embodiment 1 <Flame-retardant resin composition> The flame-retardant resin composition of this embodiment (hereinafter, sometimes referred to as "the composition") contains recycled polypropylene resin (A) (hereinafter, sometimes referred to as "recycled PP resin (A)"), a bromine-based flame retardant (B), antimony compounds (C), hydrotalcites (D), triazine-based compounds (E), a sulfur-based antioxidant (F), and a phosphorus-based antioxidant (G), and these components are blended in blending amounts described below.
[0012] The bromine-based flame retardant (B) contains at least one of 2,2-bis[3,5-dibromo-4-(2,3-dibromopropoxy)phenyl]propane (hereinafter also referred to as "TBA-BP") and bis[3,5-dibromo-4-(2,3-dibromopropoxy)phenyl]sulfone (hereinafter also referred to as "TBS-BP"). The phosphorus-based antioxidant (G) is a diphosphite compound.
[0013] The amounts of the above components in this composition are as follows: Recycled PP resin (A): 40 to 90% by weight, preferably 40 to 88% by weight Brominated flame retardant (B): 1 to 25% by weight, preferably 1 to 20% by weight Antimony compounds (C): 1 to 15% by weight, preferably 1 to 10% by weight Hydrotalcites (D): 0.1 to 10% by weight, preferably 0.5 to 5% by weight Triazine compounds (E): 0.01 to 3% by weight, preferably 0.05 to 1% by weight Sulfur-based antioxidant (F): 0.01 to 3% by weight, preferably 0.05 to 1% by weight Phosphorus-based antioxidant (G): 0.01 to 3% by weight, preferably 0.05 to 1% by weight
[0014] The amount of each component is the amount when the composition is taken as 100% by mass. When each component contains two or more compounds, the amount of each component is the total amount of the two or more compounds.
[0015] The present composition may further contain a virgin homopolypropylene resin (H) (hereinafter, sometimes referred to as "virgin homopolypropylene resin (H)"). The present composition may also contain additives other than the above-mentioned components.
[0016] The present composition contains recycled PP resin (A). The recycled PP resin (A) preferably contains 80% by weight or more of polypropylene (hereinafter sometimes referred to as "PP") as a polymer (described below). In recycling resins, for example, products (e.g., waste) containing plastic parts, such as home appliances, office equipment such as copiers, and computers, are often crushed in their entirety, and the resin is separated and recovered from the crushed material. Therefore, recycled PP resin (A) typically contains traces of other foreign matter, such as polymers other than PP, rubber, and metal. Among these, traces of metal contaminated in recycled PP resin (A) (hereinafter sometimes referred to as "contaminating metal") are thought to originate from residues of metal parts and wiring from the product, as well as from wear particles from the crushing blades used to crush the product. Metal elements and metal ions in such contaminating metals may accelerate the autoxidation reaction of PP, degrading it and potentially reducing the strength, insulation, and other physical properties of molded products. Recycled PP resin (A) is likely to contain copper as a contaminating metal, and is susceptible to copper damage caused by copper element and copper ions. In order to suppress deterioration due to contaminating metals in recycled PP resin (A), it is conceivable to use a metal capture agent that can chelate metal ions or metal elements and suppress resin deterioration due to contaminating metals.
[0017] On the other hand, since PP is flammable, antimony compounds (C), which are flame retardant aids, are sometimes added together with brominated flame retardants (B) to impart flame retardancy to the recycled PP resin (A). The brominated flame retardants (B) decompose under the influence of heat when molding the resin composition by injection molding or the like, liberating bromine, which can discolor the molded product. To capture the liberated bromine, hydrotalcites (D), which function as halogen scavengers, are added.
[0018] As described above, when preparing a composition for obtaining a flame-retardant molded article from recycled PP resin (A), it is conceivable to add a brominated flame retardant (B) and an antimony compound (C) to the recycled PP resin (A), and further add a hydrotalcite (D) to suppress discoloration of the molded article, and add a metal scavenger to suppress deterioration due to contaminating metals. However, even when a molded article is formed from a composition containing recycled PP resin (A), a brominated flame retardant (B), an antimony compound (C), a hydrotalcite (D), and a metal scavenger, discoloration has sometimes not been suppressed. This is presumably because the hydrotalcite (D) is an inorganic compound containing metals such as Mg and Al, and the metal scavenger chelates the metal ions or metal elements contained in the hydrotalcite (D), thereby deactivating the hydrotalcite's (D) function as a halogen scavenger.
[0019] This composition uses a triazine-based compound (E) as a metal scavenger, which is less likely to deactivate the halogen scavenger function of hydrotalcites (D), and also contains a sulfur-based antioxidant (F) and a phosphorus-based antioxidant (G), which is a diphosphite compound, to suppress discoloration of molded articles. Since this composition contains the above-mentioned components, it also suppresses cracking in molded articles.
[0020] Each component contained in this composition is described in detail below. (Recycled PP Resin (A)) Recycled PP Resin (A) is a resin containing, as its main component, PP recycled (reclaimed) from used resin. The main component refers to the component that is contained in the greatest amount in the recycled PP Resin (A). The PP content in the recycled PP Resin (A) is preferably 80% by weight or more, and may be 80 to 99.8% by weight, 80 to 99% by weight, 85 to 98.5% by weight, or 90 to 95% by weight.
[0021] The recycled PP resin (A) may contain other components in addition to PP, such as polymers, rubber, and metals that are mixed in the products to be recycled or during the recycling process. The content of other components in the recycled PP resin (A) is preferably 20% by weight or less, and may be 0 to 20% by weight, 0.2 to 18% by weight, 1 to 15% by weight, or 5 to 10% by weight.
[0022] Other components that may be contained in the recycled PP resin (A) include polyethylenes such as ethylene-α-olefin copolymers; polystyrenes such as styrene-based elastomers; acrylonitrile butadiene styrene (ABS); polyurethanes; rubbers such as hydrocarbon-based rubbers and silicone-based rubbers; inorganic fillers such as talc, mica, wollastonite, calcium carbonate, barium sulfate, magnesium carbonate, clay, alumina, silica, calcium sulfate, carbon fiber, glass fiber, metal fiber, silica sand, silica stone, carbon black, titanium dioxide, zinc oxide, magnesium hydroxide, asbestos, zeolite, molybdenum, diatomaceous earth, sericite, shirasu, calcium hydroxide, calcium sulfite, sodium sulfate, bentonite, kaolinite, and graphite; organic fillers such as cellulose nanofibers and cellulose microfibers; and metals. The recycled PP resin (A) may contain polyethylene and metal.
[0023] The PP contained in the recycled PP resin (A) refers to a polymer in which the propylene unit content is 50 mol% or more when the total structural units constituting the PP are taken as 100 mol%. The propylene unit content of the PP may be 70 mol% or more, 80 mol% or more, or even 90 mol% or more. The propylene unit content can be measured, for example, by nuclear magnetic resonance (NMR).
[0024] PP may be a propylene homopolymer, which is a homopolymer of propylene, or a propylene copolymer, which is a copolymer of propylene and another monomer copolymerizable with propylene. The proportion of structural units other than propylene units in the propylene copolymer is 50 mol% or less, may be more than 0 mol% and 40 mol% or less, may be 5 to 30 mol%, or may be 10 to 25 mol%. The propylene copolymer may be a random copolymer, a block copolymer, or a graft copolymer.
[0025] The propylene copolymer is preferably a copolymer of propylene and an α-olefin other than propylene. The α-olefin copolymerizable with propylene preferably includes an α-olefin having 4 to 20 carbon atoms, such as one or more selected from the group consisting of ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, and 6-methyl-1-heptene.
[0026] Examples of the propylene copolymer include a propylene-ethylene block copolymer, a propylene-butene block copolymer, a propylene-ethylene random copolymer, and a propylene-butene random copolymer.
[0027] The recycled PP resin (A) may contain only a propylene homopolymer as PP, may contain only a propylene copolymer, or may contain both a propylene homopolymer and a propylene copolymer. When the recycled PP resin (A) contains a propylene copolymer, it may contain two or more types of propylene copolymers.
[0028] Recycled PP resin (A) can be obtained, for example, by sorting and recovering PP resin from a product containing a plastic part obtained by processing, such as melt molding, a composition containing PP resin. The melt molding referred to here does not include melt molding in which PP is processed into pellets to provide the raw material PP. Recycled PP resin (A) may be a resin obtained by mechanical recycling, a resin obtained by chemical recycling, or a resin obtained by a combination of mechanical and chemical recycling.
[0029] Mechanical recycling is a method of regenerating resins without chemical reactions. In the mechanical cycle, for example, products containing plastic parts are sorted, crushed, washed, etc. to remove foreign matter and contaminants, and then pelletized or recrystallized to form a form (pellets, powder, etc.) that can be used as a raw material for the present composition, thereby obtaining recycled PP resin (A).
[0030] Chemical recycling is a method of producing resin from plastic parts, etc., through chemical reactions. For example, plastic parts are chemically decomposed to obtain monomers such as propylene, which are then polymerized to produce recycled PP resin (A).
[0031] The recycled PP resin (A) is preferably a resin obtained by mechanical recycling. The recycled PP resin (A) is preferably a resin recovered from products containing plastic parts. Examples of such products include home appliances, office automation equipment such as copiers, computers, packaging materials, containers, and automobiles. Commercially available recycled PP resins (A) may also be used.
[0032] The amount of recycled PP resin (A) in the composition is 40 to 90% by weight, preferably 40 to 88% by weight, more preferably 41.60 to 86.45% by weight, and may be 45 to 85% by weight or 50 to 80% by weight.
[0033] (Brominated flame retardant (B)) The brominated flame retardant (B) is used to impart flame retardancy to the present composition. Since the addition of a small amount of the brominated flame retardant (B) can impart flame retardancy, the use of the brominated flame retardant (B) can suppress the deterioration of the mechanical properties of the present molded article that accompanies the blending of additives such as flame retardants.
[0034] The present composition contains at least one of TBA-BP and TBS-BP as the brominated flame retardant (B), and may contain both of them.
[0035] Commercially available TBA-BP and TBS-BP may be used. Commercially available TBA-BP products include "FCP-680" (manufactured by Suzuhiro Chemical Co., Ltd.). Commercially available TBS-BP products include "FCP-65CN" (manufactured by Suzuhiro Chemical Co., Ltd.) and "Nonnen PR-2" (manufactured by Marubishi Yuka Kogyo Co., Ltd.).
[0036] The amount of brominated flame retardant (B) in the composition is 1 to 25 wt%, preferably 1 to 20 wt%, and may be 2 to 19 wt%, 5 to 18 wt%, or 8 to 16 wt%. When TBA-BP and TBS-BP are blended in the composition, the amount of brominated flame retardant (B) is the combined amount of TBA-BP and TBS-BP. When TBA-BP is blended in the composition, the amount of TBA-BP is 1 to 25 wt%, preferably 1 to 20 wt%, and may be 5 to 19 wt%, 7 to 18 wt%, or 10 to 16 wt%. When TBA-BP is blended in the composition, the amount of TBA-BP is 1 to 25 wt%, preferably 1 to 20 wt%, and may be 2 to 19 wt%, 5 to 18 wt%, or 8 to 16 wt%.
[0037] If the blending amount of the brominated flame retardant (B) exceeds the above range, the mechanical properties of the molded article formed using the present composition (hereinafter, sometimes referred to as the "present molded article") tend to deteriorate. If the blending amount of the brominated flame retardant (B) is below the above range, it becomes difficult to impart sufficient flame retardancy to the present composition.
[0038] (Antimony (C)) Antimony (C) is a compound that improves the flame retardancy effect imparted to the present composition when used in combination with brominated flame retardant (B), and functions as a flame retardant synergist. By using antimony (C) in combination with brominated flame retardant (B), the present composition can exhibit excellent flame retardancy. The present composition may contain one or more antimony (C) compounds.
[0039] The antimony compound (C) may be one or more selected from the group consisting of antimony oxides such as antimony trioxide and antimony pentoxide, and metallic antimony as a simple substance. The antimony compound (C) preferably includes an antimony oxide, and more preferably includes antimony trioxide.
[0040] The average particle size of the antimony compound (C) is, for example, 30 μm or less, preferably 10 μm or less, and more preferably 1 μm or less. From the viewpoint of ease of handling and dispersibility of the antimony compound (C), the average particle size of the antimony compound (C) is usually 0.5 μm or more. If the average particle size of the antimony compound (C) is large, dispersibility in the composition tends to decrease, making it difficult to obtain stable flame retardancy. The average particle size can be determined as the particle size at 50% cumulative value (D50) in the volume-based particle size distribution measured by laser diffraction / scattering method.
[0041] Commercially available antimony compounds (C) may be used. Commercially available antimony trioxide products include PATOX-MK (average particle size 0.51 μm, manufactured by Nippon Seiko Co., Ltd.), PATOX-M (average particle size 0.50 μm, manufactured by Nippon Seiko Co., Ltd.), PATOX-MF (average particle size 0.30 μm, manufactured by Nippon Seiko Co., Ltd.), AT3 (average particle size 1.4 μm, manufactured by Suzuhiro Chemical Co., Ltd.), AT-3TL (average particle size 1.4 μm, manufactured by Suzuhiro Chemical Co., Ltd.), and AT-3LT (average particle size 3.6 μm, manufactured by Suzuhiro Chemical Co., Ltd.).
[0042] The amount of antimony compound (C) in the composition is 1 to 15 wt %, may be 1 to 12 wt %, preferably 1 to 10 wt %, may be 2 to 9 wt %, or may be 3 to 8 wt %. When two or more types of antimony compound (C) are blended in the composition, the blending amount of antimony compound (C) is the total blending amount of the two or more types of antimony compound (C). If the blending amount of antimony compound (C) exceeds the above range, the mechanical properties of the molded article tend to deteriorate. If the blending amount of antimony compound (C) is below the above range, it becomes difficult to impart sufficient flame retardancy to the composition.
[0043] (Hydrotalcites (D)) Hydrotalcites (D) are used as halogen scavengers to capture bromine liberated from the brominated flame retardant (B) due to the influence of heat and other factors applied during molding of the composition. By including hydrotalcites (D) in the composition, bromine liberated from the brominated flame retardant (B) can be captured, thereby preventing discoloration of the molded article. The composition may contain one or more hydrotalcites (D).
[0044] The hydrotalcites (D) are inorganic compounds containing metals, and are, for example, metal double hydroxides represented by the following formula: (M1 ２＋ ) １－ｘ (M2 ３＋ ) ｘ (OH) ２ (A ｎ－ ) ｘ／ｎ ・mH ２ O [wherein, M1 represents one or more divalent metals selected from the group consisting of Mg, Ca, Ni, Zn, Fe, Mn, and Co. M2 represents one or more trivalent metals selected from the group consisting of Al, Fe, Cr, and Co. A ｎ－ Ha, OH － , CO ３ ２－ , S.O. ４ ２－ , NO ３ － , Cl － , CHCOO － , ClO ４ －x represents a positive number satisfying 0<x≦0.5; and m represents a positive number of 0 or greater than 0.
[0045] The metal double hydroxide represented by the above formula is preferably a carbonate containing at least one of Mg and Zn as M1 and Al as M2. ３．５ Zn ０．５ Al ２ (OH) １２ CO ３ ・3H ２ O and Mg ４．３ Al ２ (OH) １２．６ CO ３ ・mH ２ O. The hydrotalcites (D) may be natural products or synthetic products.
[0046] Commercially available hydrotalcites (D) may be used. Examples of commercially available hydrotalcites (D) include HT-7 (average particle size 600 nm, BET (specific surface area) value 7 m ２ / g, manufactured by Sakai Chemical Industry Co., Ltd.), HT-P (average particle size 500 nm, BET value 11 m ２ / g, manufactured by Sakai Chemical Industry Co., Ltd.), HT-9 (average particle size 500 nm, BET value 11 m ２ / g, manufactured by Sakai Chemical Industry Co., Ltd.), DHT-4A (average particle size 370 nm, BET value 11 m ２ / g, manufactured by Kyowa Chemical Industry Co., Ltd.), LH-015A (average particle size 200 nm, BET value 13 to 15 m ２ / g, manufactured by Toda Kogyo Co., Ltd.).
[0047] The average particle size of the hydrotalcites (D) is not particularly limited, but may be, for example, 100 to 900 nm, or 200 to 800 nm. The BET value of the hydrotalcites (D) is, for example, 5 to 20 nm. ２ / g, and 7 to 15m ２ The average particle size can be determined by the method described above. The BET value can be measured by the BET method in accordance with JIS Z8830.
[0048] The amount of hydrotalcite (D) in the composition is 0.1 to 10% by weight, may be 0.2 to 8% by weight, preferably 0.5 to 5% by weight, or may be 1 to 4% by weight. When two or more types of hydrotalcite (D) are blended in the composition, the blending amount of hydrotalcite (D) is the total blending amount of the two or more types of hydrotalcite (D). If the blending amount of hydrotalcite (D) exceeds the above range, the mechanical properties of the molded article tend to deteriorate. If the blending amount of hydrotalcite (D) is below the above range, the bromine scavenging ability decreases, making it difficult to suppress discoloration of the molded article.
[0049] (Triazine-based compound (E)) The triazine-based compound (E) is a compound containing a triazine ring. The triazine-based compound (E) is used as a metal capture agent that chelates metal components (metal elements or metal ions) in the composition. The triazine-based compound (E) exhibits metal component capture ability while not easily inhibiting the bromine capture ability of the hydrotalcites (D), thereby suppressing discoloration of the molded article. Because the triazine-based compound (E) has metal capture ability, it can suppress deterioration of PP and suppress deterioration of the physical properties of the molded article, such as strength and insulating properties. The composition may contain one or more triazine-based compounds (E).
[0050] The triazine-based compound (E) is preferably a compound having at least one of an amino group and an amide group, more preferably at least one of a melamine-based compound and a guanamine-based compound, and even more preferably a melamine-based compound. The melamine-based compound is a compound containing a melamine skeleton, and examples thereof include melamine and melamine salts. Examples of melamine salts include one or more selected from the group consisting of melamine cyanurate, dimelamine sulfate, melamine phosphate, and melamine polyphosphate. The melamine-based compound preferably contains at least one of melamine cyanurate and melamine. The guanamine-based compound is a compound containing a guanamine skeleton.
[0051] Commercially available products may be used as the triazine-based compound (E). Commercially available melamine cyanurate products include MC-4000 (manufactured by Nissan Chemical Industries, Ltd.), and commercially available melamine products include melamine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).
[0052] The amount of triazine compound (E) in the composition is 0.01 to 3 wt %, may be 0.03 to 2 wt %, preferably 0.05 to 1 wt %, may be 0.08 to 0.8 wt %, or may be 0.1 to 0.5 wt %. When two or more types of triazine compound (E) are blended in the composition, the amount of triazine compound (E) is the total amount of the two or more types of triazine compound (E). Even if the amount of triazine compound (E) exceeds the above range, further improvement in the metal component capture ability of the composition is unlikely to be expected. If the amount of triazine compound (E) is below the above range, it becomes difficult to obtain the metal component capture ability.
[0053] When the composition contains melamine cyanurate, the amount of melamine cyanurate in the composition is preferably 0.08 to 2 wt%, or may be 0.1 to 1.5 wt%, or may be 0.2 to 1.0 wt%. When the composition contains melamine, the amount of melamine in the composition is preferably 0.03 to 2 wt%, or may be 0.05 to 1 wt%, or may be 0.1 to 0.8 wt%. By adjusting the amounts of melamine cyanurate and melamine to the above ranges, bleeding out of additives such as the brominated flame retardant (B) can be suppressed during long-term use of the molded article or use in a high-temperature environment. This can suppress the occurrence of poor appearance of the molded article. Furthermore, suppressing bleeding out of the brominated flame retardant (B) can impart excellent flame retardancy to the molded article, allowing for the maintenance of excellent flame retardancy.
[0054] (Sulfur-based antioxidant (F)) The sulfur-based antioxidant (F) is used to complement the suppression of discoloration of the molded article and the bleed-out of additives from the molded article. The incorporation of the sulfur-based antioxidant (F) can also improve the thermal stability of the molded article. The composition may contain one or more sulfur-based antioxidants (F).
[0055] The sulfur-based antioxidant (F) is, for example, an organic compound having a thioether group, and is preferably at least one of a β-alkylmercaptopropionic acid ester compound of a polyol and a dialkylthiodipropionate compound. Examples of the β-alkylmercaptopropionic acid ester compound of a polyol include pentaerythritol tetrakis[3-laurylthiopropionate] and tetrakis[methylene(3-dodecylthio)propionate]methane. Examples of the dialkylthiodipropionate compound include distearylthiodipropionate, dilaurylthiodipropionate, and dimyristylthiodipropionate. The sulfur-based antioxidant (F) more preferably includes at least one of pentaerythritol tetrakis[3-laurylthiopropionate] and distearylthiodipropionate.
[0056] Commercially available sulfur-based antioxidants (F) may be used. Commercially available pentaerythritol tetrakis[3-laurylthiopropionate] products include AO-412S (manufactured by ADEKA Corporation) and Sumilizer TP-D (manufactured by Sumitomo Chemical Co., Ltd.). Commercially available distearyl thiodipropionate products include DSTDP (manufactured by Kyodo Pharmaceutical Co., Ltd.).
[0057] The amount of the sulfur-based antioxidant (F) in the composition is 0.01 to 3 wt %, may be 0.03 to 2 wt %, preferably 0.05 to 1 wt %, may be 0.08 to 0.8 wt %, or may be 0.1 to 0.5 wt %. When two or more sulfur-based antioxidants (F) are blended in the composition, the blending amount of the sulfur-based antioxidants (F) is the total blending amount of the two or more sulfur-based antioxidants (F). If the blending amount of the sulfur-based antioxidant (F) exceeds the above range, the effect of complementing the suppression of discoloration and bleed-out of molded articles is not improved. If the blending amount of the triazine-based compound (E) is below the above range, the effect of complementing the suppression of discoloration and bleed-out of molded articles is not achieved.
[0058] (Phosphorus-based antioxidant (G)) The phosphorus-based antioxidant (G) is used to complement the suppression of discoloration of the molded article and the bleed-out of additives from the molded article. The incorporation of the phosphorus-based antioxidant (G) can also improve the thermal stability of the molded article. The composition may contain one or more phosphorus-based antioxidants (G).
[0059] The phosphorus-based antioxidant (G) is a diphosphite compound. A diphosphite compound has a phosphite structure (P(O-) ３) and is preferably an organic compound. Examples of diphosphite compounds include 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (also known as distearyl pentaerythritol diphosphite), 3,9-bis(2,4-di-tert-butylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (also known as pentaerythritol bis(2,6-di-tert-butyl-4-phenoxy) bis(octadecyl phosphite), 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, 4,4'-butylidene-bis(3-methyl-6-t-butylphenyl-di-tridecyl phosphite), 4,4'-isopropylidene-bis(phenyl-di-alkyl(C12 to C15) phosphite), bis(decyl)pentaerythritol diphosphite, and bis(tridecyl)pentaerythritol diphosphite.
[0060] The phosphorus-based antioxidant (G) is more preferably at least one of 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane and 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane.
[0061] Commercially available products may be used as the phosphorus-based antioxidant (G). Commercially available products of 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane include PEP-36 (manufactured by ADEKA Corporation) and JPP-2000PT (manufactured by Johoku Chemical Industry Co., Ltd.). Commercially available products of 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane include PEP-8 (manufactured by ADEKA Corporation).
[0062] The amount of the phosphorus-based antioxidant (G) in the composition is 0.01 to 3 wt %, may be 0.03 to 2 wt %, preferably 0.05 to 1 wt %, may be 0.08 to 0.8 wt %, or may be 0.1 to 0.5 wt %. When two or more phosphorus-based antioxidants (G) are blended in the composition, the blending amount of the phosphorus-based antioxidants (G) is the total blending amount of the two or more phosphorus-based antioxidants (G). If the blending amount of the phosphorus-based antioxidant (G) exceeds the above range, it is difficult to improve the complementary effect of suppressing discoloration and bleed-out of molded articles. If the blending amount of the phosphorus-based antioxidant (G) is below the above range, it is difficult to obtain the complementary effect of suppressing discoloration and bleed-out of molded articles.
[0063] (New Material Homo PP Resin (H)) New material homo PP resin (H) is a so-called virgin homo PP resin. The content of homo PP in new material homo PP resin (H) is preferably 95% by weight or more, and may be 98% by weight or more, or may be 99% by weight or more. New material homo PP resin is less likely to burn in the flammability test for plastic materials described below, compared to virgin block copolymer polypropylene resin, and is more likely to exhibit excellent flame retardancy.
[0064] The melt flow rate (hereinafter sometimes referred to as "MFR") of the new homo-PP resin (H) is not particularly limited, but may be 100 g / 10 min or less, 0.5 to 80 g / 10 min, or 2 to 50 g / min, and preferably 15 g / 10 min or less. MFR can be measured in accordance with JIS K 7210 at a temperature of 230°C and a load of 2.16 kgf.
[0065] Commercially available virgin homo-PP resins (H) may be used. Examples of commercially available virgin homo-PP resins (H) include PM600M (manufactured by SunAllomer Co., Ltd.), MA3H (manufactured by Japan Polypropylene Corporation), and J105 G (manufactured by Prime Polymer Co., Ltd.).
[0066] The blending amount of virgin homo-PP resin (H) in this composition is 0 to 30% by weight, may be 0 to 25% by weight, preferably 0 to 20% by weight, may be more than 0 to 20% by weight, may be 1 to 20% by weight, or may be 5 to 15% by weight. If the blending amount of virgin homo-PP resin (H) exceeds the above range, the blending ratio of recycled PP resin (A) decreases, making it difficult to improve the utilization rate of recycled resources.
[0067] (Other Additives) The present composition may contain additives other than the recycled PP resin (A), the bromine-based flame retardant (B), the antimony compound (C), the hydrotalcite compound (D), the triazine compound (E), the sulfur-based antioxidant (F), the phosphorus-based antioxidant (G), and the virgin homo-PP resin (H).
[0068] Examples of other additives include heat stabilizers, ultraviolet absorbers, light stabilizers, antistatic agents, plasticizers, mold release agents, flame retardants other than the above-mentioned brominated flame retardants (B), flame retardant auxiliaries other than antimony compounds (C), dyes, pigments, etc. The amount of other additives to be added may be adjusted depending on the physical properties required for the composition.
[0069] (Heat Stabilizer) A heat stabilizer can be used to improve the thermal stability of the composition. Examples of the heat stabilizer include metal scavengers other than the triazine-based compound (E) described above, and antioxidants other than the sulfur-based antioxidant (F) and the phosphorus-based antioxidant (G). The composition can contain one or more heat stabilizers.
[0070] Examples of metal scavengers other than the triazine compound (E) include 3-(N-salicyloyl)amino-1,2,4-triazole, N-formiylsalicyloylhydrazine, benzotriazole, methylbenzotriazole, methylbenzotriazole potassium salt, and N,N-bis(3,5-di-t-butyl-4-hydroxyhydrocinnamate).
[0071] Examples of antioxidants other than the sulfur-based antioxidant (F) and the phosphorus-based antioxidant (G) include phenol-based antioxidants such as hindered phenol-based antioxidants, and phosphorus-based antioxidants other than diphosphite compounds.
[0072] Examples of hindered phenol antioxidants include 2,6-di-tert-butyl-p-cresol, tetrakis[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, stearyl β-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate, 3,9-bis[1,1-dimethyl-2-[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro(5,5)undecane, 1,3,5-trimethyl-2,4,6-tris(3',5'-di-tert-butyl-4-hydroxybenzyl)benzene, and triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]. Among these, from the viewpoint of heat resistance and stability, tetrakis[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, stearyl β-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate, and 3,9-bis[1,1-dimethyl-2-[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro(5,5)undecane are preferred.
[0073] The phosphorus-based antioxidant other than the diphosphite-based compound is a compound containing phosphorus element, and may be either an organic compound or an inorganic compound, but is preferably an organic compound. Examples of the organic phosphorus-based antioxidant include monophosphite-based compounds, phosphonite-based compounds, phosphinite-based compounds, phosphine-based compounds, phosphate (phosphoric acid)-based compounds, phosphonate-based compounds, phosphinate-based compounds, and phosphine oxide-based compounds, and are preferably monophosphite-based compounds.
[0074] Examples of monophosphite compounds include tris(2,4-di-tert-butylphenyl)phosphite, diphenyl mono(2-ethylhexyl)phosphite, diphenyl monodecyl phosphite, 2,2'-methylenebis(4,6-di-tert-butylphenyl)-2-ethylhexyl phosphite, tri(mononylphenyl)phosphite, alkanol (C=12 to 16) 4,4'-isopropylidenediphenol triphenyl phosphite polycondensate, bis[2,4-di-tert-butyl-6-methylphenyl]ethyl phosphite, and triallyl phosphite.
[0075] Examples of the phosphonate compounds include tetrakis(2,4-tert-butylphenyl)-4,4'-biphenyldiphosphonate.
[0076] Among the heat stabilizers described above, the present composition preferably contains a phosphorus-based antioxidant other than a phenol-based antioxidant and a diphosphite-based compound. Examples of heat stabilizers that are less likely to inhibit the bromine scavenging ability of the hydrotalcites (D) and less likely to discolor the present molded article include tetrakis[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane (AO-60, manufactured by ADEKA Corporation), tris(2,4-di-tert-butylphenyl)phosphite (2112, manufactured by ADEKA Corporation), and 2',3-bis[[3-[3,5-di-t-butyl-4-hydroxyphenyl]propionyl]]propionohydrazide (Irganox MD-1024, manufactured by BASF Japan Ltd.).
[0077] The amount of the heat stabilizer in the present composition may be, for example, 0.05 to 10% by weight, or 0.05 to 3% by weight, relative to the recycled PP resin (A).
[0078] (Ultraviolet Absorber) An ultraviolet absorber can be used to prevent the molded article from yellowing due to the influence of ultraviolet rays. The composition can contain one or more ultraviolet absorbers.
[0079] Examples of ultraviolet absorbers include hydroxybis(dimethylbenzyl)phenylbenzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol], 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, etc. Of these, from the viewpoint of weather resistance stability, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole and 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol] are preferred.
[0080] The amount of the ultraviolet absorber in the composition may be, for example, 0.05 to 10% by weight, or 0.05 to 3% by weight, relative to the recycled PP resin (A).
[0081] (Light Stabilizer) A light stabilizer can be used to prevent the molded article from yellowing due to the influence of ultraviolet light. The composition can contain one or more light stabilizers.
[0082] Examples of the light stabilizer include tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, a mixed ester of 1,2,3,4-butanetetracarboxylic acid, 1,2,3,6,6-pentamethyl-4-piperidinol, and 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, and bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate. Among these, a mixed ester of 1,2,3,4-butanetetracarboxylic acid, 1,2,3,6,6-pentamethyl-4-piperidinol, and 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane is preferred from the viewpoint of weather resistance stability.
[0083] The amount of the light stabilizer in the composition may be, for example, 0.05 to 10% by weight, or 0.05 to 3% by weight, relative to the recycled PP resin (A).
[0084] (Antistatic Agent) The antistatic agent is used to prevent adhesion of dust, dirt, etc. to the molded article. The composition may contain one or more antistatic agents.
[0085] Examples of the antistatic agent include phosphonium salt-based ionic liquids such as tributyldodecylphosphonium bis(trifluoromethanesulfonyl)imide (IL-AP3, manufactured by Koei Chemical Industry Co., Ltd.), tributyldodecylphosphonium bromide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), tetrabutylphosphonium dodecylbenzenesulfonate (manufactured by Takemoto Yushi Co., Ltd.), trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide, triethylpentylphosphonium bis(trifluoromethylsulfonyl)imide, triethyloctylphosphonium bis(trifluoromethylsulfonyl)imide, tri-n-butylmethylphosphonium bis(trifluoromethylsulfonyl)imide, and tetrabutylphosphonium tetraphenylborate; and ammonium ionic liquids such as tributylmethylammonium bis(trifluoromethylsulfonyl)imide (FC-4400, manufactured by 3M Japan Limited). pyridinium salt-based ionic liquids such as N-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide (CIL-312, manufactured by Nippon Carlit Co., Ltd.); imidazolium salt-based ionic liquids; pyrrolidinium salt-based ionic liquids; lithium ionic liquids such as lithium bistrifluoromethanesulfonylimide / polyether polyol (PEO-20R, manufactured by Sanko Chemical Industry Co., Ltd.); polyols having a quaternary ammonium salt in the side chain; Polymer-type antistatic agents (1SX-1090, 1WX-1020-NS, manufactured by Taisei Fine Chemical Co., Ltd.); glycerin fatty acid esters such as diglycerin monolaurate (Poem DL-100, manufactured by Riken Vitamin Co., Ltd.); polymer-type permanent antistatic agents such as Pelektron HS, Pelektron AS, Pelestat NC6321 (manufactured by Sanyo Chemical Industries, Ltd.), and Adekastab AS-302 (manufactured by ADEKA Corporation); Biomicelle BN-105 (chemical formula: C ４２ H ８１ O ８ B.C. ２３ H ４８ ON ２ , manufactured by Boron Laboratory Co., Ltd.), and Biomicelle BN-77 (chemical formula: C ４２ H ８１ O ８ B.C. ２３ H ４８ON, manufactured by Boron Laboratory Co., Ltd.) and other donor-acceptor compounds.
[0086] (Plasticizer) The composition may contain one or more plasticizers, such as polyethylene glycol, polyamide oligomer, ethylene bisstearamide, phthalate ester, adipate ester, polystyrene oligomer, polyethylene wax, and mineral oil.
[0087] (Release Agent) The present composition may contain one or more release agents, such as polyethylene wax, silicone oil, long-chain carboxylic acid, metal salt of long-chain carboxylic acid, and higher fatty acid ester of monohydric or polyhydric alcohol.
[0088] (Flame Retardant) The flame retardant referred to in the present disclosure refers to a flame retardant other than the brominated flame retardant (B). The present composition may contain one or more flame retardants.
[0089] Examples of the flame retardant include phosphorus-based flame retardants such as bisphenol A bis(diphenyl phosphite), tricresyl phosphate, triphenyl phosphate, and tris-3-chloropropyl phosphate; bromine-based flame retardants other than the bromine-based flame retardant (B), such as ethylene bispentabromobenzene and hexabromocyclododecane; silicone-based flame retardants; and hydroxide-based flame retardants such as magnesium hydroxide and aluminum hydroxide.
[0090] (Flame retardant aid) In the present disclosure, the flame retardant aid refers to a flame retardant aid other than the antimony compound (C). The present composition may contain one or more flame retardant aids. Examples of the flame retardant aid include PTFE (polytetrafluoroethylene).
[0091] <Method for Producing Flame-Retardant Resin Composition> The method for producing a flame-retardant resin composition of the present embodiment (hereinafter, sometimes referred to as "present production method (1)") is a method for producing the present composition.
[0092] This production method (1) includes, for example, a step of obtaining a blend containing recycled PP resin (A), a brominated flame retardant (B), antimony compounds (C), hydrotalcites (D), triazine compounds (E), a sulfur-based antioxidant (F), and a phosphorus-based antioxidant (G), and, if necessary, at least one of virgin homo-PP resin (H) and other additives. In this production method (1), the above components can be blended in the amounts described for the present composition. This production method (1) may also include a step of kneading the blend obtained in the above step.
[0093] Examples of the method for kneading the blend include physical blending methods such as melt kneading, solvent cast blending, latex blending, and polymer complexing, but the melt kneading method is preferred. When the blend is melt kneaded, the melt kneading temperature is, for example, 180 to 220°C, and may be 180 to 210°C. Melt kneading at a temperature exceeding this temperature range is likely to induce deterioration of the brominated flame retardant (B).
[0094] Examples of devices for kneading the blend include a tumbler, a Henschel mixer, a rotary mixer, a super mixer, a ribbon tumbler, and a V-blender. When using these devices, the present composition may be obtained by uniformly dispersing each component contained in the blend, melt-kneading the mixture, and pelletizing the mixture. Pelletization by melt-kneading may be performed using a single-screw or multi-screw extruder, but a Banbury mixer, roller, co-kneader, blast mill, Prabender blauthograph, or the like may also be used. The present composition may be produced by batch or continuous operation.
[0095] The present production method (1) may be carried out by so-called mold blending, in which the compounded material before melt-kneading is placed in the heating barrel of a molding machine and melt-kneaded.
[0096] Embodiment 2. <Molded Article> The molded article of this embodiment is a molded article (present molded article) formed using the present composition. Since the present molded article is formed using the present composition, discoloration can be suppressed. Furthermore, the occurrence of cracks in the present molded article can also be suppressed.
[0097] As described above, by adjusting the type and amount of the triazine compound (E) blended in the composition used to obtain the molded article, it is possible to suppress the bleeding out of the additive from the molded article, thereby suppressing the occurrence of poor appearance of the molded article, and also imparting and maintaining excellent flame retardancy to the molded article.
[0098] The molded article can achieve 1.5 mm V-0 in UL94 (flammability test for plastic materials) of the UL standard (Underwriters Laboratories Inc.). When the molded article is formed using the composition containing the new homo-PP resin (H), it can prevent the absorbent cotton from igniting in the above-mentioned flammability test, and excellent flame retardancy can be obtained.
[0099] The shape of the molded article is not particularly limited and can be selected depending on the application and intended use of the molded article. The shape of the molded article may be, for example, a plate, plate-like, rod-like, sheet-like, film-like, cylindrical, annular, circular, elliptical, polygonal, hollow, frame-like, box-like, panel-like, or a combination of one or more of these. The molded article may be, for example, a housing, a component, or a display window of various devices such as home appliances and office automation equipment, an automobile interior panel, a headlamp lens of an automobile such as a motorcycle, or a lighting cover. The surface of the molded article may have a textured surface or a three-dimensional curved surface. The molded article may have a single-layer structure or a multi-layer structure. When the molded article has a multi-layer structure, at least one layer may be formed using the present composition, and all layers may be formed using the present composition.
[0100] <Method for producing a molded article> The method for producing a molded article of this embodiment (hereinafter sometimes referred to as "Present Production Method (2)") is a method for molding the Present Composition or the Present Composition produced by Present Production Method (1). Present Production Method (2) can be a method for producing the Present Molded Article.
[0101] The molding method of the present composition is not particularly limited, and examples thereof include injection molding, injection compression molding, extrusion molding, profile extrusion, transfer molding, blow molding, gas-assisted blow molding, blow molding, extrusion blow molding, IMC (in-mold coating) molding, rotational molding, multilayer molding, two-color molding, insert molding, sandwich molding, foam molding, and pressure molding. Known molding conditions can be used for these molding methods.
[0102] The molding method is preferably injection molding or injection compression molding (hereinafter, sometimes referred to as "injection molding, etc."). In injection molding, etc., the composition is exposed to high temperatures during molding, which tends to cause decomposition of the brominated flame retardant (B) and liberate bromine. Since the present composition is used in Production Method (2), discoloration caused by liberated bromine can be suppressed even when the molded article is produced by injection molding, etc. Furthermore, by adjusting the type and amount of the triazine compound (E) blended in the composition, bleeding out of the additive from the molded article can be suppressed. Therefore, the molded article has excellent appearance characteristics and flame retardancy, and is likely to maintain its excellent flame retardancy.
[0103] The present composition used in the present production method (2) may be a pelletized product of melt-kneading the above-mentioned blend, or may be a molten product obtained by melt-kneading the blend.
[0104] Hereinafter, the present disclosure will be described in more detail with reference to examples and comparative examples, but the present disclosure is not limited to these examples.
[0105] [Examples 1 to 17, Comparative Examples 1 to 5] The components were blended to obtain the compositions shown in Tables 1 to 3, and the blends were melt-kneaded at 180 to 220°C using a twin-screw kneading extruder ("TEX-26SX" manufactured by Shibaura Kogyo Co., Ltd.) to obtain pellets of flame-retardant resin composition having lengths of 3 to 5 mm. The pellets were then molded using an electric injection molding machine ("NEX110IV-9EG" manufactured by Nissei Plastic Industrial Co., Ltd.) to obtain flat-plate-shaped molded articles measuring 100 mm long x 100 mm wide x 2 mm thick. The injection molding conditions were a resin temperature of 180 to 210°C and a mold temperature of 50°C.
[0106] In Tables 1 to 4, each symbol indicates the following component: (Recycled PP Resin (A)) A-1: Recycled polypropylene resin (manufactured by Green Cycle Systems Co., Ltd. This is a recycled PP resin that was sorted and recovered from mixed plastic fragments from home appliances.)
[0107] (Brominated flame retardants (B)) B-1: TBA-BP (2,2-bis[3,5-dibromo-4-(2,3-dibromopropoxy)phenyl]propane; "FCP-680" manufactured by Suzuhiro Chemical Co., Ltd.) B-2: TBS-BP (bis[3,5-dibromo-4-(2,3-dibromopropoxy)phenyl]sulfone; "Nonnen PR-2" manufactured by Marubishi Yuka Kogyo Co., Ltd.)
[0108] (Antimony (C)) C-1: Antimony trioxide ("PATOX-MK" manufactured by Nihon Seiko Co., Ltd.)
[0109] (Hydrotalcites (D)) D-1: Metal double hydroxide ("HT-7" manufactured by Sakai Chemical Industry Co., Ltd.) D-2: Metal double hydroxide ("DHT-4A" manufactured by Kyowa Chemical Industry Co., Ltd.)
[0110] (Triazine-based compounds (E)) E-1: Melamine cyanurate ("MC-4000" manufactured by Nissan Chemical Industries, Ltd.) E-2: Melamine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
[0111] (Sulfur-based antioxidants (F)) F-1: Pentaerythritol tetrakis[3-laurylthiopropionate] ("AO-412S" manufactured by ADEKA Corporation) F-2: Distearyl thiodipropionate ("DSTDP" manufactured by Kyodo Pharmaceutical Co., Ltd.)
[0112] (Phosphorus-based antioxidants (G)) G-1: 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane ("PEP-36" manufactured by ADEKA Corporation) G-2: 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane ("PEP-8" manufactured by ADEKA Corporation)
[0113] (New homo PP resin (H)) H-1: New homo polypropylene resin ("PM600M" manufactured by SunAllomer Co., Ltd.) H-2: New homo polypropylene resin ("MA3H" manufactured by Japan Polypropylene Corporation)
[0114] (Other Additives) Heat Stabilizer: A mixture of tetrakis[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane (phenolic antioxidant, manufactured by ADEKA Corporation under the name "AO-60") and tris(2,4-di-tert-butylphenyl)phosphite (monophosphite compound phosphorus-based antioxidant, manufactured by ADEKA Corporation under the name "2112").
[0115] (Metal Scavenger) Decamethylenedicarboxylic acid disalicyloyl hydrazide ("CDA-6" manufactured by ADEKA Corporation)
[0116] [Evaluation of Color Difference] The components were blended to obtain the compositions shown in Tables 1 to 3, and the blends were kneaded and molded using a small blender Xplore MC15 (manufactured by DSM Corporation) and an injection molding machine Xplore IM12 (manufactured by DSM Corporation) to prepare flat test pieces (1) (length 80 mm x width 30 mm x thickness 2 mm). The kneading conditions were a barrel temperature of 210°C, a cylinder rotation speed of 120 rpm, and a kneading time of 2 minutes, and the injection molding conditions were a cylinder temperature of 210°C and a mold temperature of 50°C. After leaving the test piece (1) for one day in an environment at a temperature of 23°C and a humidity of 50%, the L of the test piece (1) was measured using a spectrophotometer (field of view 10°) within a range of φ3 mm. ＊ a ＊ b ＊ Lightness L according to color system ０ ＊ , hue a ０ ＊ , hue b ０ ＊ was measured (initial value). For color measurement, the SCI (Specular Component Include) method was adopted, which takes into account specular reflection light and allows evaluation regardless of the surface condition of the test piece (1). A D65 light source was used as the light source for color measurement.
[0117] A test piece (2) (length 80 mm x width 30 mm x thickness 2 mm) was prepared in the same manner as in the measurement of the initial lightness and hue, except that the kneading time was changed to 12 minutes. ＊ a ＊ b ＊ Lightness L according to color system ＊ , hue a ＊ , hue b ＊ was measured (value after 10 minutes of retention test).
[0118] Using the initial value and the value after the retention test obtained above, the color difference ΔE was calculated according to the following formula. The smaller the ΔE, the smaller the degree of discoloration. The results are shown in Tables 1 to 3.
[0119] [Evaluation of Bleedout] Pellets of the flame-retardant resin compositions obtained in the Examples and Comparative Examples were molded using an injection molding machine to prepare multipurpose test pieces A in accordance with JIS K7139. An accelerated aging test of the multipurpose test piece A was carried out in accordance with JIS K7368, with the test temperature set to 140°C and the test time set to 500 hours. After the accelerated aging test, any deposits on the surface of the multipurpose test piece A were confirmed visually or by wiping with an alcohol-impregnated wipe, and evaluated according to the following criteria. The results are shown in Tables 1 to 3. A: No deposits were observed. B: Deposits were observed.
[0120] [Evaluation of cracks] Cracks on the surface of the multipurpose test piece type A used for the evaluation of bleed-out were observed visually or with an optical microscope and evaluated according to the following criteria. The results are shown in Tables 1 to 3. A: No cracks were observed. B: Cracks were observed.
[0121]
[0122]
[0123]
[0124] The molded articles of Examples 1 to 17 have small ΔE values, which indicates that discoloration of the molded articles is suppressed. It is also clear that the occurrence of cracks is suppressed in the molded articles of Examples 1 to 17. A comparison of Examples 1 to 16 with Example 17 indicates that bleed-out from the molded articles can be suppressed by adjusting the type and amount of triazine-based compound (E). A comparison of Examples 1 to 15 with Examples 16 and 17 indicates that discoloration of the molded articles can be further suppressed by adjusting the amounts of hydrotalcites (D), triazine-based compound (E), sulfur-based antioxidant (F), and phosphorus-based antioxidant (G).
[0125] On the other hand, in Comparative Examples 1 to 5, since at least one of the hydrotalcites (D), triazine-based compounds (E), sulfur-based antioxidants (F), and phosphorus-based antioxidants (G) was not blended, it was found that discoloration of the molded article was hardly suppressed. It was found that the hydrazide-based metal capture agent used in Comparative Example 3 was unable to suppress discoloration of the molded article.
[0126] The embodiments and examples disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.
Claims
1. A flame-retardant resin composition, Recycled polypropylene resin (A) 40-90% by weight, Brominated flame retardant (B) 1 to 25% by weight, Antimony compounds (C) 1 to 15% by weight, Hydrotalcite (D) 0.1-10% by weight, 0.01 to 3% by weight of a triazine compound (E), Sulfur-based antioxidant (F) 0.01 to 3% by weight, It is formulated with 0.01 to 3% by weight of a phosphorus-based antioxidant (G), The brominated flame retardant (B) comprises at least one of 2,2-bis[3,5-dibromo-4-(2,3-dibromopropoxy)phenyl]propane and bis[3,5-dibromo-4-(2,3-dibromopropoxy)phenyl]sulfone, The phosphorus-based antioxidant (G) is a diphosphite compound in the flame-retardant resin composition.
2. The flame-retardant resin composition according to claim 1, wherein the triazine compound (E) is a melamine compound.
3. The flame-retardant resin composition according to claim 2, wherein the melamine compound comprises at least one of melamine cyanurate and melamine.
4. The melamine-based compound comprises melamine cyanurate, The flame-retardant resin composition according to claim 2, wherein the amount of melamine cyanurate blended in the flame-retardant resin composition is 0.08 to 2% by weight.
5. The melamine-based compound contains melamine, The flame-retardant resin composition according to claim 2, wherein the amount of melamine in the flame-retardant resin composition is 0.03 to 2% by weight.
6. The amount of recycled polypropylene resin (A) blended is 40 to 88% by weight. The amount of the brominated flame retardant (B) is 1 to 20% by weight. The amount of antimony (C) is 1 to 10% by weight. The amount of hydrotalcite (D) is 0.5 to 5% by weight. The amount of the aforementioned triazine compound (E) is 0.05 to 1% by weight. The amount of the sulfur-based antioxidant (F) is 0.05 to 1% by weight. The flame-retardant resin composition according to claim 1, wherein the amount of the phosphorus-based antioxidant (G) is 0.05 to 1% by weight.
7. The flame-retardant resin composition according to claim 1, wherein the sulfur-based antioxidant (F) comprises at least one of pentaerythritol tetrakis[3-laurylthiopropionate] and distearyl thiodipropionate.
8. The flame-retardant resin composition according to claim 1, wherein the phosphorus-based antioxidant (G) comprises at least one of 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane and 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane.
9. Furthermore, the flame-retardant resin composition according to claim 1 is further comprising 30% by weight or less of the new homopolypropylene resin (H).
10. A molded article formed using the flame-retardant resin composition described in any one of claims 1 to 9.
11. A method for producing a flame-retardant resin composition according to any one of claims 1 to 9, A method for producing a flame-retardant resin composition, comprising the step of obtaining a compound comprising at least the recycled polypropylene resin (A), the brominated flame retardant (B), the antimony (C), the hydrotalcite (D), the triazine compound (E), the sulfur-based antioxidant (F), and the phosphorus-based antioxidant (G).
12. A method for producing a molded article, comprising molding a flame-retardant resin composition according to any one of claims 1 to 9.
13. The method for manufacturing a molded article according to claim 12, wherein the flame-retardant resin composition is injection molded or injection compression molded.