Resin composition

Abstract

(Problem) To provide a resin composition having superior thermal stability while ensuring flame retardancy of the resin composition. (Solution) The resin composition according to the present disclosure contains 100 parts by weight of a resin, 5 parts by weight or less of an antimony-based flame retardant and 2 parts by weight or more of hydrotalcite represented by formula (1) with respect to 100 parts by weight of the resin. Formula (1): MgxZnyAl2(OH)zA·nH2O (in the formula, 2.0 ≤ x ≤ 5.0, 0 < y < 4.0, 3 < (x+y) < 6, ((x+y)×2)+4 ≥ z, 0 ≤ n < 8), A is at least one selected from CO3 2-, SO4 2-, Cl-, NO3 -, PO4 3-.

Description

resin composition

[0001] The present invention relates to a resin composition, and more particularly to a resin composition with excellent flame retardancy.

[0002] In recent years, with the advancement of communication networks, the use of various types of cables, such as optical cables, electric cables, and wire cables, has increased due to the spread of electric vehicles. In particular, there is a growing demand for high flame retardancy when these cables are heated.

[0003] Furthermore, while it is known that antimony-based flame retardants are used to impart high flame retardancy to resins, there is also a need to reduce the amount of antimony-based flame retardants, which are heavy metals.

[0004] As a resin composition that reduces the amount of antimony-based flame retardants, it is known that some of the antimony is replaced with hydrotalcite instead of the antimony-based flame retardants (Patent Document 1).

[0005] Furthermore, as a resin composition that reduces the amount of antimony-based flame retardant, it is also known to contain hydrotalcite containing a high concentration of Zn instead of the antimony-based flame retardant (Patent Document 2).

[0006] Japanese Patent Publication No. 2024-011405, Japanese Patent Publication No. 2020-500998

[0007] By the way, when used in electrical wires and cables, they are sometimes colored to distinguish each cable from the others.

[0008] However, for example, if exposed to high temperatures in the engine compartment, the resin tends to change in quality due to the heat and turn black, which can make it difficult to distinguish between different cables.

[0009] The object of this disclosure is to provide a resin composition that has better thermal stability while ensuring the flame retardancy of the resin composition.

[0010] [1] One aspect of the present disclosure provides a resin composition comprising 100 parts by weight of a resin, 5 parts by weight or less of an antimony-based flame retardant and 2 parts by weight or more of hydrotalcite represented by formula (1) per 100 parts by weight of the resin. Mg ｘ Zn ｙAl ２ (OH) ｚ A·nH ２ O ··· (1) (wherein 2.0≦x≦5.0, 0<y<4.0, 3<(x+y)<6, ((x+y)×2)+4≧z, 0≦n<8) A is CO ３ ２－ , SO ４ ２－ , Cl － , NO ３ ― , PO ４ ３－ at least one selected from the group consisting of.

[0011] [2] In another aspect of the present disclosure, there is provided the resin composition according to [1] above, further comprising 1 to 5 parts by weight of hydrotalcite represented by formula (2). Mg ｐ Al ２ (OH) ｑ B·mH ２ O ··· (2) (wherein p≦6, q≦(2p+4), 0≦m≦6) B is CO ３ ２－ , SO ４ ２－ , Cl － , NO ３ ― , PO ４ ３－ at least one selected from the group consisting of.

[0012] [3] In another aspect of the present disclosure, there is provided the resin composition according to [1] or [2] above, further comprising aluminum hydroxide and / or magnesium hydroxide.

[0013] [4] In another aspect of this disclosure, the hydrotalcite provides the resin composition according to any one of [1] to [3] above, wherein the endothermic peak temperature determined by TG-DTA analysis is at least 190 to 230°C. [5] In another aspect of this disclosure, the resin provides the resin composition according to any one of [1] to [3] above, wherein the resin contains a brominated flame retardant or a halogenated flame retardant. [6] In another aspect of this disclosure, the resin composition according to any one of [1] to [3] above, wherein the resin is a vinyl chloride resin or a polyolefin resin. [7] In another aspect of this disclosure, the resin composition according to any one of [1] to [6] above, wherein the specific optical density (Ds at 4.0 min) measured in accordance with the ASTM E662 test method is 100 or less.

[0014] The present invention aims to provide a resin composition with superior thermal stability while ensuring flame retardancy. In addition, the resin composition of one embodiment of this disclosure can reduce the amount of smoke produced during combustion, thereby enabling good visibility (ensuring clear visibility) when evacuating in the event of a fire or other accident, and thus reducing the risk of difficulty in evacuation due to poor visibility and secondary disasters.

[0015] This figure shows the results of the thermal stability test for the examples and comparative examples. This figure shows the results of the thermogravimetric differential thermal analysis for the examples. This figure shows the change in specific optical density Ds up to 20 min for the examples and comparative examples. This figure shows the results for specific optical density Ds (1.5 min) and (4.0 min) for the examples and comparative examples.

[0016] An embodiment of this disclosure will be described in detail below, but the scope of the present invention is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of the invention. Furthermore, if multiple upper and lower limits are given for a particular parameter, any combination of these upper and lower limits can be used to create a suitable numerical range.

[0017] (Resin Composition) A resin composition according to one embodiment of the present disclosure comprises 100 parts by weight of resin, 5 parts by weight or less of an antimony-based flame retardant and 2 parts by weight or more of hydrotalcite represented by formula (1) per 100 parts by weight of resin. Mg ｘ Zn ｙ Al ２ (OH) ｚ A.nH ２ O...(1) (wherein, 2.0≦x≦5.0, 0<y<4.0, 3<(x+y)<6, ((x+y)×2)+4≧z, 0≦n<8) A is CO ３ ２－ , SO ４ ２－ , Cl － NO ３ ― , PO ４ ３－ At least one selected from the following.

[0018] (Resin) Any suitable resin can be used as the resin. Examples include thermoplastic resins and thermosetting resins. Thermoplastic resins are preferably used.

[0019] Any suitable resin can be used as the thermoplastic resin. For example, as chlorine-containing resins, vinyl chloride resins such as polyvinyl chloride, chlorinated polyvinyl chloride, polyvinylidene chloride, chlorinated polyethylene, chlorinated polypropylene, vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer, ethylene-vinyl chloride-vinyl acetate graft copolymer, vinyl chloride-propylene copolymer, vinyl chloride-styrene copolymer, vinyl chloride-isobutylene copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-styrene-maleic anhydride terpolymer, vinyl chloride-styrene-acrylonitrile copolymer, vinyl chloride-butadiene copolymer, vinyl chloride-isoprene copolymer, vinyl chloride-chlorinated propylene copolymer, vinyl chloride-vinylidene chloride-vinyl acetate terpolymer, vinyl chloride-maleic acid ester copolymer, vinyl chloride-methacrylate ester copolymer, vinyl chloride-acrylonitrile copolymer, vinyl chloride-various vinyl ether copolymers can be used; and chlorine-based rubbers such as chloroprene rubber, chlorinated butyl rubber, chlorosulfonated polyethylene rubber, chlorinated polyethylene rubber, and epichlorohydrin rubber can be used. Furthermore, instead of chlorine-containing resins, halogen-containing resins, such as bromine-containing resins, can also be used.

[0020] Furthermore, when using other thermoplastic resins that do not contain halogen elements such as chlorine, it is desirable to use them in combination with halogen-based flame retardants. Examples of other thermoplastic resins that do not contain halogen elements such as chlorine include polyolefin resins such as polyethylene, polypropylene, ethylene-propylene copolymer, polybutene, poly(4-methylpentene-1), C2-C8 (carbon 2-8) olefin (α-olefin) polymers or copolymers thereof, copolymers of these C2-C8 olefins and dienes, polystyrene resins such as polystyrene, ABS resin, AAS resin, AS resin, MBS resin, urethane resin, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl (meth)acrylate copolymer, polyester, etc. Only one type of thermoplastic resin may be used, or two or more types may be used in combination. For example, it can be used in the form of a mixture of a chlorine-containing resin and another thermoplastic resin that does not contain chlorine, a block copolymer, or a graft copolymer.

[0021] Any suitable thermosetting resin can be used. Examples include epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin, phenolic resins such as novolac phenol resin and polyoxystyrene, melamine resins such as butylated melamine resin, urea resin, unsaturated polyester resin, bismaleimide resin, and urethane resins. Only one type of thermosetting resin may be used, or two or more types may be used in combination.

[0022] Examples of halogenated flame retardants include brominated flame retardants and chlorinated flame retardants. Examples of brominated flame retardants include decabromodiphenyl ether (DecaBDE), octabromodiphenyl ether (OctaBDE), pentabromodiphenyl ether (PentaBDE), tetrabromobisphenol A (TBBPA), TBBPA epoxy oligomer, TBBPA carbonate oligomer, TBBPA bis(dibromomethylpropyl ether), tribromophenol, hexabromocyclododecane (HBCD), hexabromobenzene (HBB), pentabromotoluene, ethylenebis(pentabromopeny), ethylenebistetrabromophthalimide, 1,2 Examples include -dibromo-4-(1,2-dibromoethyl)cyclohexane, tetrabromocyclooctane, hexabromotoluene, brominated polystyrene (BPS), brominated epoxy resin, ethylene bispentabromodiphenyl (EBPBP), bis(tribromophenoxy)ethane (BTBPE), brominated polyphenylene ether, pentabromopolybenzyl acrylate, 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine, brominated butadiene / styrene copolymer, decabromodiphenylethane (DBDPE), dibromoneopentyl glycol (DBNPG), etc. Examples of chlorine-based flame retardants include chlorinated paraffin and perchloropentacyclodecane (Dechlorane Plus). When these halogen-based flame retardants are used, the hydrogen halide (e.g., HBr) generated during combustion reacts with the zinc component in hydrotalcite represented by formula (1) to form zinc halides (e.g., ZnBr). ２ This generates a char layer, which increases the amount of char (carbonized layer) formed during combustion, thereby improving flame retardancy.

[0023] (Antimony-based flame retardants) Any suitable antimony-based flame retardant can be used. Examples include antimony trioxide, antimony tetroxide, antimony pentoxide, sodium antimonate, etc. Antimony trioxide is preferably used. One type of antimony-based flame retardant may be used, or two or more types may be used in combination.

[0024] The antimony-based flame retardant content is 5 parts by weight or less per 100 parts by weight of resin, preferably 3 parts by weight or less, more preferably 2 parts by weight or less, and even more preferably 1 part by weight or less. When used in combination with hydrotalcite represented by formula (1), it is possible to reduce the amount of antimony-based flame retardant added and provide a resin composition with superior thermal stability while ensuring high flame retardancy. In addition, the resin composition of one embodiment of this disclosure can reduce the amount of smoke emitted during combustion, thereby enabling good visibility (ensuring a clear field of view) when evacuating in the event of a fire accident, and thus reducing the risk of difficulty in evacuation due to poor visibility and secondary disasters.

[0025] In one embodiment, the resin composition may not contain an antimony-based flame retardant (i.e., the antimony-based flame retardant content is 0 parts by weight). According to the resin composition of the embodiment of this disclosure, flame retardancy can be achieved even if an antimony-based flame retardant is not included.

[0026] (Hydrotalcite) A resin composition according to one embodiment of the present disclosure contains 2 parts by weight or more of hydrotalcite represented by formula (1). A resin composition containing hydrotalcite represented by formula (1) can reduce the amount of antimony-based flame retardant added and, while ensuring flame retardancy, may have better thermal stability and better visibility when evacuating in the event of a fire accident or the like.

[0027] In one embodiment, the resin composition of one embodiment of the present disclosure does not need to contain an antimony-based flame retardant. By using hydrotalcite represented by formula (1), high flame retardancy (e.g., V-0 rating in the UL-94V combustion test) (e.g., an LOI (Limiting Oxygen Index) of 30% or more) can be achieved even without the presence of an antimony-based flame retardant.

[0028] Furthermore, generally, when the resin contained in a resin composition and hydrotalcite are heated, the double bond portion within the resin molecule and the metal ions contained in the hydrotalcite (for example, Mg) ２＋Because these substances form metal complexes, the resin may become discolored depending on the coordination color of the complex. This is considered to be one of the reasons why the resin composition changes color and turns black when heated.

[0029] The resin composition of one embodiment of this disclosure contains zinc (Zn), therefore, if other metal ions (e.g., Mg) are present, ２＋ Even if (etc.) forms a metal complex with the double bond portion within the resin molecule, the zinc ion (Zn) that is similarly formed ２＋ The presence of a metal complex between the resin molecule and the double bond portion of the resin molecule results in complementary coordination colors of the complexes, canceling each other out and consequently suppressing the discoloration of the resin. In other words, it is possible to suppress the resin composition from changing color and turning black due to heat. That is, the resin composition of one embodiment of the present disclosure may have excellent thermal stability (for example, a small change ΔE in the degree of yellowness (Y.I) over time when heated at a predetermined temperature).

[0030] A resin composition according to one embodiment of the present disclosure, when containing hydrotalcite represented by formula (1), can achieve high flame retardancy without reducing or using other flame retardants such as antimony-based flame retardants, while also providing superior thermal stability and excellent visibility during evacuation in the event of a fire or other accident. Hydrotalcite represented by formula (1) may be used alone or in combination of two or more types. Mg ｘ Zn ｙ Al ２ (OH) ｚ A.nH ２ O...(1) (wherein, 2.0≦x≦5.0, 0<y<4.0, 3<(x+y)<6, ((x+y)×2)+4≧z, 0≦n<8) A is CO ３ ２－ , SO ４ ２－ , Cl － NO ３ ― , PO ４ ３－ At least one selected from the following.

[0031] In equation (1), x is a number less than or equal to 5.0, preferably less than or equal to 4.5, and more preferably less than or equal to 4.0. Also, x is a number greater than or equal to 2.0, preferably greater than or equal to 2.5, and more preferably greater than or equal to 3.0.

[0032] In formula (1), y is a number greater than 0 and less than 4.0. y is greater than 0, preferably 0.5 or greater, more preferably 1.0 or greater, and even more preferably 2.0 or greater. Also, y is less than 4.0, preferably 3.5 or less, and even more preferably 3.0 or less.

[0033] In equation (1), x + y is a number greater than 3.0, preferably 4.0 or greater, and more preferably 5.0 or greater. Also, x + y is a number less than 6.0, preferably 5.0 or less, and more preferably 4.0 or less.

[0034] In equation (1), z is a number less than or equal to (x + y) × 2 + 4. For example, z is a number less than or equal to 16.0, preferably less than or equal to 15.0, more preferably less than or equal to 14.0, and even more preferably less than or equal to 13.0. There is no particular upper limit to z. However, if z is too large, it may be difficult to form the structure of hydrotalcite.

[0035] In formula (1), n ​​is a number greater than or equal to 0, more preferably 2.0 or greater, more preferably 3.0 or greater, more preferably 3.5 or greater, more preferably 4.0 or greater, more preferably 4.5 or greater, and even more preferably 5.0 or greater. There is no particular upper limit to n. However, if n is too large, it may be difficult to form the structure of hydrotalcite, so n may be 10.0 or less, 9.0 or less, or 8.0 or less, or even 3.5 or less.

[0036] In formula (1), A is preferably an anion, and in particular CO ３ ２－ , SO ４ ２－ , Cl － NO ３― , PO ４ ３－ It is at least one chemical group selected from the following.

[0037] The hydrotalcite represented by formula (1) is preferably Mg ３ Zn １ Al ２ (OH) １２ CO ３ 3.0H ２ O can be used. By using these hydrotalcites, it is possible to reduce the amount of antimony-based flame retardants added, and to provide a resin composition that has better thermal stability and visibility when evacuating in the event of a fire, while ensuring high flame retardancy.

[0038] In a resin composition according to one embodiment of the present disclosure, the lower limit of the hydrotalcite content represented by formula (1) is 2 parts by weight or more, preferably 5 parts by weight or more, and more preferably 6 parts by weight or more. This allows the resin composition to reduce the amount of antimony-based flame retardant added, while maintaining flame retardancy, and to have better thermal stability and excellent visibility when evacuating in the event of a fire or other accident. The upper limit of the hydrotalcite content represented by formula (1) is not particularly limited, but if it is too high, the content of other components in the resin composition will relatively decrease, so it may be adjusted as appropriate depending on the purpose of the resin composition and the desired properties. For example, the hydrotalcite content represented by formula (1) may further be 20 parts by weight or less, 18 parts by weight or less, or 15 parts by weight or less.

[0039] The resin composition of one embodiment of the present disclosure may further contain 1 to 5 parts by weight of hydrotalcite represented by formula (2). Mg ｐ Al ２ (OH) ｑ B・mH ２ O ... (2) (wherein p ≤ 6, q ≤ (2p + 4), 0 ≤ m ≤ 6, that is, p is a number less than or equal to 6, q is a number less than or equal to (2p + 4), and m is a number between 0 and 6.) B is CO ３ ２－ , SO ４ ２－ , Cl－ , NO ３ ― , PO ４ ３－ which is at least one selected from. Use of these hydrotalcites can improve the flame retardancy of the resin composition.

[0040] In formula (2), p is a number of 6 or less, preferably 5 or less, more preferably 4.3 or less, still more preferably 4.2 or less. The lower limit of p is not particularly limited. However, when p is too small, it tends to be difficult to form a structure as hydrotalcite, so p may be 2.0 or more, 2.5 or more, or 3.0 or more.

[0041] In formula (2), q is a number of (2p+4) or less, for example, preferably 12.6 or less, more preferably 12.2 or less, still more preferably 12.0 or less. The lower limit of q is not particularly limited. However, when q is too small, it tends to be difficult to form a structure as hydrotalcite, so q may be 8.0 or more, 9.0 or more, or 10.0 or more.

[0042] In formula (2), m is a number of 0 or more, preferably 1.0 or more, more preferably 2.0 or more, still more preferably 2.5 or more. The upper limit of m is not particularly limited. However, when m is too large, it tends to be difficult to form a structure as hydrotalcite, so m may be 5.0 or less, 4.5 or less, or 3.5 or less.

[0043] In formula (2), B is preferably an anion, CO ３ ２－ , SO ４ ２－ , Cl － , NO ３ ― , PO ４ ３－ which is at least one chemical group selected from.

[0044] As the hydrotalcite represented by formula (2), preferably Mg ４ Al２ (OH) １２ CO ３ 3H ２ O, Mg ４．３ Al ２ (OH) １２．６ CO ３ 3.3H ２ O can be used. By using these hydrotalcites, thermal stability can be improved.

[0045] The resin composition of one embodiment of the present disclosure can be made to have its thermal stability enhanced by using 1 part by weight or more, preferably 2 parts by weight or more, and more preferably 3 parts by weight or more, of hydrotalcite represented by formula (2). The upper limit of the content of hydrotalcite represented by formula (2) is not particularly limited, but if it is too high, the content of other components in the resin composition will relatively decrease, so it may be adjusted as appropriate depending on the purpose of the resin composition and the desired properties. For example, the content of hydrotalcite represented by formula (2) may be 5 parts by weight or less, 4.5 parts by weight or less, or 4 parts by weight or less.

[0046] <Surface Treatment> The hydrotalcite represented by formula (1) or formula (2) above may also be subjected to a surface treatment to improve its dispersibility in the resin. The surface treatment agents that can be used for this surface treatment are not particularly limited, but examples include anionic surfactants, cationic surfactants, phosphate ester treatment agents, silane coupling agents, titanate coupling agents, aluminum coupling agents, silicone treatment agents, silicic acid, and water glass. Particularly preferred surface treatment agents include at least one selected from the group consisting of oleic acid, stearic acid, octanoic acid, and octicic acid. The amount of the surface treatment agent is not particularly limited, but is, for example, 0.1 to 10% by mass, preferably 0.5 to 5% by mass, relative to the mass of the hydrotalcite.

[0047] (Aluminum hydroxide and / or magnesium hydroxide) The resin composition of one embodiment of the present disclosure may further contain an inorganic flame retardant such as aluminum hydroxide and / or magnesium hydroxide. By using these aluminum hydroxide and / or magnesium hydroxide, the flame retardancy of the resin composition can be enhanced. As inorganic flame retardants, in addition to the above-mentioned aluminum hydroxide (which may also be ATH) and magnesium hydroxide (which may also be MDH), metal hydroxides such as calcium hydroxide can be used. In addition, as other inorganic compounds, zinc borate, zinc stannate, zinc stannate hydroxide, zinc molybdate, ammonium molybdate, expanded graphite, kaolin, talc, montmorillonite, silica, magnesium silicate, etc. can be used.

[0048] Aluminum hydroxide has the chemical formula Al(OH) ３ Examples include gibbsite and vialite, represented as AlO(OH), and boehmite. Typical manufacturing methods involve dissolving and purifying natural bauxite using NaOH, followed by recrystallization. Magnesium hydroxide is not particularly limited, and commonly used magnesium hydroxide known in this field can be used. For example, magnesium hydroxide derived from seawater or brine can be used. Natural brucite, magnesite, magnesium carbonate, and basic magnesium carbonate (e.g., 4MgCO) are readily available and have high purity. ３ Mg(OH) ２ 4H ２ O or Mg ５ (CO ３ ) ４ (OH) ２ 4H ２ Magnesium hydroxide obtained from raw materials such as O) can be used. Aluminum hydroxide and / or magnesium hydroxide can have their performance improved by surface treatment and particle size control for resin addition, and their purity and particle size can be selected according to the application.

[0049] In the resin composition of one embodiment of the present disclosure, the content of an inorganic flame retardant such as aluminum hydroxide and / or magnesium hydroxide is not particularly limited.

[0050] The lower limit of the content of inorganic flame retardants such as aluminum hydroxide and / or magnesium hydroxide may be adjusted as appropriate so as to ensure that the effect of enhancing the flame retardancy of the resin composition is sufficiently obtained. For example, the content may be 3 parts by weight or more, 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, or 30 parts by weight or more.

[0051] Furthermore, regarding the upper limit of the content of inorganic flame retardants such as aluminum hydroxide and / or magnesium hydroxide, if the content is excessive, the content of other components in the resin composition will relatively decrease, so it may be adjusted as appropriate depending on the purpose of the resin composition and the desired properties. For example, the content may be 50 parts by weight or less, 45 parts by weight or less, or 40 parts by weight or less.

[0052] Inorganic flame retardants such as aluminum hydroxide and / or magnesium hydroxide (MDH) may be subjected to a surface treatment to improve their dispersibility in the resin. Examples of surface treatment agents that can be used for this surface treatment include anionic surfactants such as higher fatty acids, phosphate esters, silane coupling agents, titanate coupling agents, aluminum coupling agents, and silicones. The amount of the surface treatment agent is not particularly limited, but it is preferably used in an amount of 0.1 to 15% by weight relative to the inorganic flame retardant such as aluminum hydroxide and / or magnesium hydroxide (MDH).

[0053] (Phosphorus-based flame retardants) The resin composition of one embodiment of the present disclosure may further contain a phosphorus-based flame retardant. Examples of phosphorus-based flame retardants include organophosphorus and inorganic phosphorus-based flame retardants. Examples of organophosphorus-based flame retardants include triphenyl phosphate (TPP), tricresyl phosphate (TCP), resorcinol bis(diphenyl phosphate) (RDP), bisphenol A bis(diphenyl phosphate) (BDP), triethyl phosphate (TEP), tris(chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCPP), tris(1,3-dichloro-2-propyl) phosphate (TDCP), tributyl phosphate (TBP), etc. By using these, in addition to char formation in the solid phase (condensed phase), a radical scavenging effect in the gas phase can also be expected, and flame retardancy is enhanced by a synergistic effect with hydrotalcite represented by formula (1). Examples of inorganic phosphorus-based flame retardants include red phosphorus, ammonium phosphate (APP), and ammonium polyphosphate. By using these, a phosphate glass layer is formed during combustion, and combined with the improved flame retardancy due to the carbonization-promoting effect of hydrotalcite represented by formula (1), a stronger char can be formed.

[0054] Inorganic phosphorus-based flame retardants may be classified into orthophosphate-based, phosphite-based, hypophosphite-based, inorganic phosphate composites (hybrid systems), phosphate nanomaterials, or condensed phosphate systems, and these may be included individually or in combination.

[0055] Examples of orthophosphate compounds include ammonium triphosphate (APP), sodium triphosphate (STPP), sodium pyrophosphate, aluminum metaphosphate, calcium metaphosphate, aluminum orthophosphate (AlPO4), magnesium phosphate (Mg3(PO4)2), calcium phosphate (Ca3(PO4)2), zinc phosphate (Zn3(PO4)2), iron phosphate (FePO4), zirconium phosphate (ZrP2O7, Zr3(PO4)4), titanium phosphate (TiP2O7), and cerium phosphate (CePO4). These orthophosphates undergo a dehydration reaction upon thermal decomposition, contributing to char formation. Furthermore, they form a glassy barrier layer with phosphoric acid at high temperatures, exhibiting an oxygen-blocking effect. In addition, the oxidation and capture of smoke products by metal species (Al, Mg, Zn, etc.) contribute to improved smoke suppression.

[0056] Examples of phosphite compounds include aluminum hydrogen phosphite (AlHPO3), magnesium hydrogen phosphite (MgHPO3), calcium hydrogen phosphite (CaHPO3), zinc phosphite (ZnHPO3), and metal phosphites (such as Fe, Mn, and Cu). These phosphite compounds exhibit radical scavenging activity during thermal decomposition and contribute to carbonization by being converted to phosphoric acid through oxidation. Furthermore, the aggregation and capture of smoke particles by the metal species contribute to improved smoke suppression.

[0057] Examples of hypophosphite compounds include aluminum hypophosphite (Al(H2PO2)3), magnesium hypophosphite (Mg(H2PO2)2), calcium hypophosphite (Ca(H2PO2)2), zinc hypophosphite (Zn(H2PO2)2), and sodium hypophosphite (NaH2PO2). These hypophosphite compounds exhibit gas-phase flame retardancy by thermal decomposing at relatively low temperatures (200-300°C) and generating phosphorus-containing radicals such as PH3 and PO in the gas phase.

[0058] Examples of inorganic phosphate-based composites (hybrid systems) include aluminum phosphate-aluminum hydroxide (AlPO4-Al(OH)3) composites, magnesium phosphate-magnesium hydroxide (Mg3(PO4)2-Mg(OH)2) composites, zinc phosphate-zinc oxide (Zn3(PO4)2-ZnO) composites, and iron phosphate double salts (FePO4 composites). These composites exhibit high effectiveness in both flame retardancy and smoke suppression due to the synergistic action of carbonization promotion by phosphate and endothermic decomposition and barrier formation by metal hydroxides and oxides.

[0059] Examples of phosphate-based nanomaterials include nanoaluminum phosphate (nanoAlPO4), nanotitanium pyrophosphate (TiP2O7), and layered zirconium phosphate (ZrP). These phosphate-based nanomaterials are organic-inorganic hybrid phosphates in which the carbonization of the organic portion and the dehydration of the inorganic phosphate work synergistically to form a dense carbonized layer.

[0060] Examples of condensed phosphoric acid compounds include ammonium polyphosphate (APP), melamine polyphosphate (MPP), and ammonium pyrophosphate. These condensed phosphoric acid compounds undergo stepwise deammonia and dehydration reactions upon heating, producing phosphoric acid or polyphosphate, and ultimately converting to orthophosphoric acid. The polyphosphate produced in this process exhibits a strong dehydrating effect, promoting the formation of a carbonized layer. Furthermore, the non-flammable gases such as ammonia produced by decomposition have a diluting effect on flammable gases. (Nitrogen-based and silicone-based flame retardants)

[0061] The resin composition of one embodiment of the present disclosure may further contain a nitrogen-based flame retardant or a silicone-based flame retardant. Examples of nitrogen-based flame retardants include melamine, melamine cyanurate, melamine polyphosphate (MPP), melamine pyrophosphate, melamine phosphate, melamine borate, and other melamine derivatives, as well as guanidine compounds and triazine derivatives. These expand and foam during combustion, causing the carbonized layer to thicken, and exhibit a synergistic effect with the carbonization-promoting effect of hydrotalcite represented by formula (1). Examples of silicone-based flame retardants include polysiloxane. Silicone-based flame retardants strengthen the char, and through a synergistic effect with the carbonization-promoting effect of hydrotalcite represented by formula (1), the shielding performance during combustion is improved.

[0062] (Dehydration temperature of hydrotalcite represented by formula (1) above) In a resin composition according to one embodiment of the present disclosure, the hydrotalcite represented by formula (1) above may have an endothermic peak temperature of TG-DTA of at least 190 to 230°C. This makes it possible to suppress the temperature rise when the resin is heated based on the dehydration of hydrotalcite, thereby improving flame retardancy. TG-DTA can be measured, for example, using a thermogravimetric differential thermal analyzer (Bruker AXS TG-DTA2000SA). Note that in the measurement using a thermogravimetric differential thermal analyzer, Al ２ O ３ It can be used as a standard substance. Furthermore, in thermogravimetric differential thermal analysis, measurements can be taken under conditions of 50 mL / min. air flow and a heating rate of 10°C / min.

[0063] (Other Additives) The resin composition may contain any other suitable additives. Examples of other additives include plasticizers, stabilizers such as organic acid metal salts, β-diketone compounds, fillers, waxes, heat-resistant additives, UV absorbers, antioxidants, crosslinking additives, and flame retardants other than antimony-based flame retardants. These additives may be used individually or in combination of two or more.

[0064] (Specific optical density (Ds at 4.0 min) at 4.0 min after the start of combustion is 100 or less) The resin composition of one embodiment of the present disclosure may have a specific optical density (Ds at 4.0 min) at 4.0 min after the start of combustion, measured in accordance with the ASTM E662 test method, of 100 or less. The specific optical density Ds at X min after the start of combustion is referred to as Ds at X min, and may be abbreviated as DsX min.

[0065] The amount of smoke emitted during combustion, and consequently the specific optical density Ds, can be evaluated by testing in accordance with ASTM E662, "Standard test method for specific optical density of smoke generated from solid materials." As will be described in detail later, this test aims to quantitatively evaluate the concentration of smoke generated when a material is on fire by measuring the attenuation of light due to the smoke generated from the test specimen and calculating the specific optical density Ds.

[0066] Specific optical density Ds is an index that indicates the smoke concentration at a certain time after the start of the test. It is used to evaluate the rate and concentration of smoke generation in the initial stages of a fire and is a physical property that directly relates to visibility and safety during evacuation. Aircraft companies and others evaluate the amount of smoke emitted 4.0 minutes after the start of combustion from the point of ensuring visibility during evacuation in the initial stages of a fire. If the specific optical density (Ds at 4.0 min) at 4.0 minutes after the start of combustion is 100 or less, it can be said that the amount of smoke emitted during combustion is small. This makes it possible to achieve good visibility (ensuring visibility) when evacuating in the event of a fire accident, and thus reduces the risk of difficulty in evacuation due to poor visibility and secondary disasters. In general, the lower the specific optical density Ds, the less smoke is emitted and the better the visibility. In that respect, the specific optical density Ds may be 90 or less, preferably 85 or less, and more preferably 80 or less. The lower limit of specific optical density Ds is not particularly limited and is theoretically 0 or more, and may exemplify 10 or more, 20 or more, or 30 or more.

[0067] (Method for preparing the resin composition) The resin composition of one embodiment of the present invention can be manufactured by any suitable method. For example, the resin, an antimony flame retardant, and hydrotalcite represented by formula (1), and any other suitable components (e.g., hydrotalcite represented by formula (2), or aluminum hydroxide and / or magnesium hydroxide) can be mixed by any suitable means. The mixing can be carried out by any suitable method. For example, it is preferable to mix the materials in a Henschel mixer or a super mixer and then uniformly knead the resulting mixture using a roll, Banbury mixer, extruder, etc.

[0068] <Method for evaluating flame retardancy (UL-94V combustion test)> The flame retardancy of a resin composition can be evaluated by the UL-94V combustion test.

[0069] UL-94 is a standard for evaluating the flammability of plastic materials, established by Underwriters Laboratories (UL) in the United States. Specifically, "UL94V" refers to the vertical combustion test, which has three grades: V-0, V-1, and V-2. The specific test methods and criteria are as follows:

[0070] Test Method (Preparation of Test Specimens): For each sample, prepare five test specimens measuring 125 ± 5 mm in length and 13.0 ± 0.5 mm in width. Attach the test specimens to clamps and hold them vertically. In this disclosure, test specimens with a thickness of 3 mm are used.

[0071] (Combustion Test) Apply a 20 mm flame to the lower end of the test specimen for 10 seconds. If the combustion is extinguished within 30 seconds, immediately apply the flame again for 10 seconds.

[0072] The following criteria are determined based on the results of the combustion test. V-0 indicates the best flame retardancy, followed by V-1 and V-2, indicating decreasing flame retardancy. (The criteria for V-2 are omitted.)

[0073] V-0: No burning continues for more than 10 seconds after any flame contact. No red-hot glowing continues for more than 30 seconds after the second flame contact. No particles fall that would ignite the gauze placed 300 mm below. The total burning time for 10 flame contacts on 5 test pieces does not exceed 50 seconds.

[0074] V-1: No combustion continues for more than 30 seconds after any flame contact. No red-hot glow continues for more than 60 seconds after the second flame contact. No particles fall that would ignite the gauze placed 300 mm below. The total burning time for 10 flame contacts on 5 test pieces does not exceed 250 seconds.

[0075] Furthermore, the amount of smoke produced during combustion can be observed through combustion tests. Generally, a smaller amount of smoke is preferable. The quantitative evaluation methods for smoke quantity, smoke concentration, and the specific optical density Ds based on these will be described later.

[0076] Furthermore, combustion tests allow observation of char (carbonized and burnt material) formed on the test specimen after combustion. Generally, the less char there is, the higher the thermal stability, which is preferable.

[0077] Through combustion tests and thermal stability tests, test specimens can be searched for that exhibit smoke emission, char formation, or chemical stability (or yellowness) within the desired range, thereby obtaining a resin composition with appropriate components or formulation.

[0078] <Method for evaluating flame retardancy (LOI [Limiting Oxygen Index])> The flame retardancy of resin compositions can be evaluated by LOI based on JIS K7201-2:2021 "Plastics - Test methods for flammability by oxygen index - Part 2: Tests at room temperature".

[0079] The LOI (Liquid Oxygen Index) is an index that indicates the minimum oxygen concentration required for a material to maintain combustion. A higher LOI indicates that the material is less flammable. The specific test methods and criteria are as follows:

[0080] Test Method (Preparation of Test Specimens): For each sample, prepare a test specimen of standard size: 70–150 mm in length, 6.5–10 mm in width, and 3–10 mm in thickness. Hold each test specimen vertically.

[0081] (Supply of oxygen-nitrogen mixed gas:) A mixture of oxygen and nitrogen gas is supplied into the test apparatus (flammability tester ON-1D manufactured by Suga Test Machine Co., Ltd.). The upper end of the test specimen is ignited while adjusting the oxygen concentration.

[0082] (Observation of combustion:) Measure the minimum oxygen concentration required for the test specimen to maintain combustion. If combustion lasts for more than 3 minutes or the combustion length is 50 mm or more, record the oxygen concentration.

[0083] The following criteria are determined based on the results of the combustion test. A higher LOI indicates that the material is less flammable and has higher flame retardancy.

[0084] Oxygen Index (LOI): Below 22%: Highly flammable. 23% to 26%: Flammable but self-extinguishing. 27% to 29%: Difficult to flammable. Above 30%: Even more difficult to flammable.

[0085] <Method for evaluating thermal stability> The thermal stability of a resin composition can be evaluated by a static thermal stability test.

[0086] The thermal stability is evaluated by heating the sample to a predetermined temperature and measuring the yellowness (Y.I.: Yellow Index) of the sample at 0 minutes and 30 minutes of heating. A smaller change ΔE in the yellowness (Y.I.) indicates superior thermal stability. A colorimeter (ZE-2000, manufactured by Nippon Denshoku Co., Ltd.) is used to measure the yellowness.

[0087] Yellowness (Y.I.) refers to the degree to which a color deviates from colorless or white towards yellow. Generally, a lower yellowness (Y.I.) indicates better coloring properties. A smaller change in yellowness (Y.I.) ΔE is preferable because it maintains color even after prolonged heating.

[0088] The specific testing methods and evaluation criteria are as follows:

[0089] Test Method: The resin composition to be tested is kneaded at 170°C for 5 minutes using an 8-inch roll machine (NS-200, manufactured by Nishimura Machinery Co., Ltd.) to create a test roll sheet with a thickness of 0.7 mm. The resulting roll sheet is made into a test piece measuring 4 cm in length and width, placed on a stainless steel plate, and a thermal stability test is performed in a gear oven (GPHH-100, manufactured by ESPEC Corporation) at 190°C with an openness of 60%.

[0090] The evaluation method for thermal stability is as follows: the yellowness (Y.I.) is measured at 0 minutes of heating and at 30 minutes of heating, and the difference ΔE between the yellowness (Y.I.) is calculated. A smaller ΔE indicates superior thermal stability. A colorimeter (ZE-2000, manufactured by Nippon Denshoku Co., Ltd.) is used to measure the yellowness.

[0091] ΔE: ΔE ≤ 30: ○ (The difference ΔE in yellowness (Y.I.) is small, indicating excellent thermal stability.) 30 < ΔE < 50: △ (The difference ΔE in yellowness (Y.I.) is somewhat large, indicating slightly inferior thermal stability.) 50 ≤ ΔE: × (The difference ΔE in yellowness (Y.I.) is large, indicating poor thermal stability.)

[0092] <Test in accordance with ASTM E662 "Standard test method for specific optical density of smoke generated from solid materials"> The amount of smoke emitted or the concentration of smoke when a resin composition is burned, and the specific optical density Ds therefrom, can be evaluated by a test in accordance with ASTM E662 "Standard test method for specific optical density of smoke generated from solid materials".

[0093] This test is conducted in accordance with ASTM E662, with the test specimen positioned vertically in a sealed test chamber. The test specimen is subjected to radiant heating from a heater and irradiated with a flame from a burner. Smoke is generated from the test specimen, and the light transmittance in the test chamber changes (usually attenuates). The light transmittance is measured at 0.5-minute intervals for a maximum of 20 minutes from the start of the test (heating). The specific optical density Ds is calculated based on the light transmittance before the start of the test and the light transmittance after a certain period of time (usually 1.5 minutes and 4.0 minutes) from the start of the test.

[0094] In other words, specific optical density Ds is an index that indicates the smoke concentration at a certain time after the start of the test. It is used to evaluate the rate and concentration of smoke generation in the initial stages of a fire and is a physical property that directly relates to visibility and safety during evacuation. Generally, materials with a high specific optical density Ds value produce a large amount of smoke or a high concentration of smoke, which can increase the risk of difficulty in evacuation due to poor visibility and secondary disasters. Aircraft companies and others evaluate materials based on the amount of smoke produced 4.0 minutes after the start of combustion, in order to ensure visibility during evacuation in the initial stages of a fire.

[0095] The specific testing methods and evaluation criteria are as follows:

[0096] Test Method (Preparation of Test Specimens): The test specimens consist of homogeneous material with a thickness of 0.0745 to 0.0830 inches (approximately 1.89 to 2.11 mm). Each sample (test specimen) is a separate material and is dried at 140°F (approximately 60°C) for 24 hours before testing.

[0097] (Measurement of light transmittance:) Before starting the test, the temperature of the test chamber is set to 76±5°F (approximately 24.4±2.8°C), the relative humidity to 50±10%, and the chamber wall temperature to 95±4°F (approximately 35±2.2°C). The test specimen is placed in the sealed test chamber, vertically mounted using a dedicated mount. In addition to radiant heating from a heater, the test specimen is irradiated with a flame from a burner. The light transmittance inside the chamber, which changes as smoke is generated, is measured. Measurements are taken at 0.5-minute intervals for a maximum of 20 minutes, with one measurement taken for each sample (test specimen).

[0098] (Calculation of specific optical density Ds:) Based on the ratio (transmittance T) of the intensity of transmitted light during the test to the intensity of transmitted light before the test, the specific optical density Ds is calculated using the following formula: Ds = [V / (A・L)]・log(100 / T) T = (I / Io) × 100 T: Transmittance (%) Io: Intensity of transmitted light before the test I: Intensity of transmitted light during the test V: Volume of the smoke chamber (m³) ３ ) A: Surface area of ​​the sample (test specimen) (cm² ２ ) L: Optical path length (m)

[0099] Judgment Criteria: If the specific optical density (Ds at 4.0 min) at 4.0 minutes after the start of combustion is 100 or less, it can be said that the amount of smoke produced during combustion is small. This makes it possible to achieve good visibility (securing a clear line of sight) when evacuating in the event of a fire accident, and thus reduces the risk of difficulty in evacuation due to poor visibility and secondary disasters.

[0100] The present disclosure will be further described below with reference to examples and comparative examples, but the present disclosure is not limited to these examples.

[0101] (Preparation of hydrotalcite) <Hydrotalcite I (Mg ３ Zn １ Al ２ (OH) １２ CO ３ 3.0H ２ O)> Hydrotalcite I is MgCl ２ and ZnCl ２ and Al ２ (SO ４ ) ３ Mixed solution A was prepared with a molar ratio of 3.0:1.0:1.0. Meanwhile, NaOH and Na ２ CO ３ OH:CO ３ Mixed solution B was prepared in a ratio of 12:1. Mixed solution A and mixed solution B were mixed under sufficient stirring to achieve a pH of 9-10, and a hydrotalcite suspension was obtained. The obtained suspension was then mixed with 0.1 mol / L Na ２ CO ３ Wash and remove CO2 from the interlayer ions. ３ The material was converted to ions. Afterward, it was thoroughly washed with deionized water, the resulting wash was resuspended, and hydrothermal treatment was performed at 150°C for 12 hours. The obtained hydrotalcite was surface-treated with 2% by weight of sodium stearate to obtain the hydrotalcite described above. Figure 2 shows the results of thermogravimetric differential thermal analysis of hydrotalcite I. TG-DTA was prepared by using Al as the standard substance. ２ O ３ The measurement conditions were as follows: atmosphere: air, heating rate: 10°C / min, and the temperature was measured using a thermogravimetric differential thermal analyzer (Bruker AXS TG-DTA2000SA).

[0102] <Hydrotalcite II (Mg ４．３ Al ２ (OH) １２．６ CO ３ 3.3H ２ O)> Hydrotalcite II is MgCl ２ and Al ２ (SO ４ ) ３ Mixed solution A was prepared with a molar ratio of 4.3:1.0. Meanwhile, NaOH and Na ２ CO ３ OH:CO ３ Mixed solution B was prepared in a ratio of 12.1:1. Mixed solution A and mixed solution B were mixed under sufficient stirring to achieve a pH of 9-10, and a hydrotalcite suspension was obtained. The obtained suspension was then diluted with 0.1 mol / L Na ２ CO ３ Wash and remove CO2 from the interlayer ions. ３ The material was converted to ions. Afterward, it was thoroughly washed with deionized water, the resulting wash was resuspended, and hydrothermally treated at 170°C for 12 hours. The resulting hydrotalcite was then surface-treated with 3% by weight of sodium stearate to obtain the hydrotalcite described above.

[0103] <Hydrotalcite III (Zn ４ Al ２ (OH) １２ CO ３ 3.0H ２ O)> 4 L of a 1 mol / L aqueous solution of zinc chloride and 1 L of a 1 mol / L aqueous solution of aluminum sulfate were added to a 15 L reaction vessel. While stirring, a mixture of 6 L of a 2 mol / L aqueous solution of NaOH and 1 L of a 1 mol / L aqueous solution of sodium carbonate was added dropwise until the pH reached 9.5. After solid-liquid separation of the resulting reaction product, impurities were washed away, the mixture was re-emulsified to a concentration of 50 g / L, and hydrothermally aged at 120°C for 20 hours. The resulting slurry was surface-treated with 2% sodium stearate, then dehydrated, washed, dried at 100°C, and finely ground with a test hammer mill to obtain a test sample.

[0104] <Hydrotalcite IV (Mg ４ Al ２ (OH) １２ CO ３3H ２ O) > MgCl ２ and Al ２ (SO ４ ) ３ Hydrotalcite can be obtained in the same manner as in Sample 2, except that mixed solution A is prepared to have a molar ratio of 4.0:1.0. The above-mentioned hydrotalcite can be obtained by surface-treating this hydrotalcite with 2% by weight stearic acid.

[0105] (Preparation of Resin Composition) 100 parts by weight of vinyl chloride resin (Shin-Etsu Chemical Co., Ltd.: TK-1000) was mixed with 50 parts by weight of plasticizer (Daihachi Chemical Industry Co., Ltd., octyl trimellitate (TOTM)), 0.8 parts by weight of lubricant (dry zinc stearate: BS-28182, manufactured by Yushi Seihin Co., Ltd.), 0.2 parts by weight of stabilizer I (DBM (dibenzoylmethane): DBM-83, manufactured by NANJING LANYA CHEMICAL), 3.5 parts by weight of stabilizer II (hydrotalcite IV), 0.3 parts by weight of antioxidant (BASF IRGANOX 1010), antimony flame retardant (antimony trioxide, manufactured by Yamanaka Sangyo Co., Ltd., trade name: MSW), and hydrotalcite I to III prepared above in the amounts shown in Table 1 to obtain the resin compositions of the examples and comparative examples.

[0106]

[0107] Using the resin compositions obtained in this manner, flame retardancy was evaluated (UL-94V combustion test and LOI limiting oxygen index) and static thermal stability tests were performed to evaluate the flame retardancy and thermal stability of each resin composition. The procedures and evaluation criteria for each test are as described above.

[0108] The results of the flame retardancy evaluation are shown in Table 1. For the overall flame retardancy evaluation, materials that met V-0 in the UL-94V combustion test and had an LOI of 30.0% or higher were marked with a circle (○). Other materials were marked with a cross (×).

[0109] The results of the thermal stability evaluation are shown in Table 1. Figure 1 shows photographs of the samples taken during the thermal stability test.

[0110] The resin composition of the example contains hydrotalcite I (hydrotalcite represented by formula (1)), and as shown in Table 1, the overall flame retardancy evaluation was ○ and the thermal stability evaluation was also ○. ○ indicates a good evaluation, △ indicates an insufficient evaluation, and × indicates a poor evaluation.

[0111] In Examples 1 and 2, the total content of hydrotalcite I and antimony trioxide was the same, but the mixing ratios were different. During the combustion test for flame retardancy evaluation, it was confirmed that Example 1, which had a high hydrotalcite content (6 parts by weight) and a low antimony trioxide content (1 part by weight), produced less smoke for approximately 1.5 minutes from the start of combustion than Example 2, which had a low hydrotalcite content (5 parts by weight) and a high antimony trioxide content (2 parts by weight), and that the amount of smoke produced thereafter was almost the same. In addition, in the test pieces after the combustion test, Example 1, which had a high hydrotalcite content, showed more char formation than Example 2, which had a low hydrotalcite content. On the other hand, in the thermal stability test, Example 2, which had a low hydrotalcite content, showed a higher yellowness (Y.I.) related to thermal stability than Example 1, which had a high hydrotalcite content.

[0112] The comparative resin compositions did not contain hydrotalcite represented by formula (1). As shown in Table 1, these comparative resin compositions received a score of × or △ in at least one of the overall flame retardancy evaluation or thermal stability evaluation.

[0113] Comparative Example 1 did not contain an antimony-based flame retardant, and its overall flame retardancy rating was ×. Comparative Example 2 contained an antimony-based flame retardant, and its overall flame retardancy rating was ○, but its thermal stability test rating was ×. Comparative Examples 3 and 4 contained an antimony-based flame retardant and hydrotalcite III (not the hydrotalcite represented by formula (1)), but at least one of the overall flame retardancy rating or thermal stability rating was × or △. (The content of antimony-based flame retardant and hydrotalcite III differed in Comparative Examples 3 and 4.) Comparative Example 5 contained an antimony-based flame retardant and hydrotalcite II (not the hydrotalcite represented by formula (1)), but its overall flame retardancy rating was ×.

[0114] (Evaluation of specific optical density Ds) A resin composition for evaluating the specific optical density Ds was prepared separately. The resin composition was prepared by mixing the components in the amounts listed in Table 2, in the same manner as described above, except that magnesium hydroxide I was added in Examples 3 to 6.

[0115] (Preparation of Magnesium Hydroxide I) To prepare magnesium hydroxide I, acetic acid equivalent to 50 mol% of magnesium was added and dissolved as an organic substance to 300 mL of a 2 mol / L magnesium chloride aqueous solution to obtain a mixed aqueous solution. This mixed aqueous solution was placed in a 1 L container, and 300 mL of a 3.2 mol / L sodium hydroxide aqueous solution was added under stirring to induce a precipitation reaction. The amount of NaOH contained in the sodium hydroxide aqueous solution is equivalent to 0.8 equivalents for 1 mole of magnesium contained in the magnesium chloride aqueous solution. The obtained precipitate product was transferred to a 1 L autoclave and subjected to hydrothermal treatment at 130°C for 4 hours under stirring. After cooling to below 100°C, it was removed from the autoclave, filtered, washed with water, dried, pulverized, and sieved to obtain magnesium hydroxide I.

[0116]

[0117] The specific optical density Ds of the obtained resin composition was evaluated. The test procedure and evaluation criteria are as described above.

[0118] The results for the specific optical density Ds of the resin composition are shown in Table 2. The specific optical density Ds (1.5 min) is the value obtained 1.5 minutes after the start of the test (combustion), and the specific optical density Ds (4.0 min) is the value obtained 4.0 minutes after the start of the test (combustion).

[0119] Figure 3 shows a chart plotting the specific optical density Ds acquired at 0.5-minute intervals from the start of the test until 20 minutes had elapsed for Examples 1 and 2, and Comparative Examples 1 and 2.

[0120] The resin composition of the example contained hydrotalcite I (hydrotalcite represented by formula (1)), and as shown in Table 2, the specific optical density Ds (1.5 min) was 100 or less, and the specific optical density Ds (4.0 min) was 81 or less. Since the specific optical density Ds (4.0 min) 4.0 minutes after the start of combustion was 100 or less, good visibility (securing a clear field of view) can be achieved when evacuating in the event of a fire accident, etc., which means that the risk of difficulty in evacuation due to poor visibility and secondary disasters can be reduced.

[0121] Referring to Figure 3, in Examples 1 and 2, a peak in Ds appeared approximately 1.5 minutes after the start of combustion, and then remained relatively stable at approximately 80 until 20 minutes later. In other words, although the amount of smoke is high immediately after the start of combustion, the amount of smoke is low after 1.5 minutes and thereafter, so Ds (1.5 min) and Ds thereafter are stable at approximately 80, confirming that good visibility (ensuring clear field of view) can be achieved.

[0122] The comparative resin compositions do not contain hydrotalcite represented by formula (1). As shown in Table 2, the specific optical density Ds (1.5 min) of these comparative resin compositions is in the range of 130 to 170, and the specific optical density Ds (4.0 min) was approximately 170. Since all Ds values ​​exceed 100, it is difficult to achieve good visibility (securing a clear field of view) when evacuating in the event of a fire or other accident, meaning that the risk of difficulty in evacuation due to poor visibility and secondary disasters cannot be reduced.

[0123] Referring to Figure 3, in Comparative Examples 1 and 2, Ds increased almost monotonically until approximately 2.0 minutes after the start of combustion, and thereafter Ds never fell below 170. Occasionally, peaks where Ds rose sharply were observed, and some of these peaks showed Ds values ​​exceeding 200. In other words, the amount of smoke generally tended to increase until 2.0 minutes after the start of combustion, and there was no decrease in the amount of smoke until 20 minutes had passed. Therefore, Ds (1.5 min) and Ds thereafter never fell below 170, confirming that good visibility (ensuring a clear field of view) was difficult to achieve.

[0124] Referring to Figure 4, in the comparative examples, Comparative Example 1, which did not contain antimony trioxide, had a high Ds (1.5 min) of 170, and it was observed that Ds (1.5 min) tended to decrease to 130 as the antimony trioxide content increased (Comparative Examples 2, 6, and 7). However, Ds (4.0 min) increased to approximately 170 regardless of the antimony trioxide content, and no significant difference was observed among the comparative examples. In contrast, in Examples 1 to 6, no clear difference was observed due to the increase or decrease in antimony trioxide, and it was confirmed that Ds (4.0 min) decreased from Ds (1.5 min) in all examples.

[0125] This disclosure provides a resin composition that ensures flame retardancy while exhibiting superior thermal stability. Therefore, this resin composition can be suitably used in applications such as electric wires and cables, printed circuit boards, housings, cable sheathing, connectors, etc. in the electrical and electronic equipment sector, engine room components, interior materials, wire harnesses, etc. in the automotive industry, thermal insulation materials, wallpaper, flooring, roofing materials, adhesives, paints, etc. in the building and construction sector, work clothes, curtains, carpets, industrial filters, etc. in the textile and apparel sector, sofas, mattresses, curtains, cushioning materials, etc. in the furniture and interior design sector, seats, interior materials, cables, thermal insulation materials, etc. in the aviation, railway, and marine sectors, and foamed materials, pallets, containers, etc. in the packaging and logistics sector. For example, even when electric wires and cables are exposed to high temperatures in an engine room, the resin composition can suppress deterioration and blackening due to heat, making cable identification easier. Furthermore, the amount of antimony-based flame retardant added can be reduced with this resin composition. In addition, the resin composition of one embodiment of the present disclosure can reduce the amount of smoke produced during combustion, thereby enabling good visibility (ensuring a clear line of sight) when evacuating in the event of a fire or other accident, and thus reducing the risk of difficulty in evacuation due to poor visibility and secondary disasters.

Claims

1. A resin composition comprising 100 parts by weight of a resin, 5 parts by weight or less of an antimony-based flame retardant relative to 100 parts by weight of the resin, and 2 parts by weight or more of hydrotalcite represented by formula (1): Mg ｘ Zn ｙ Al ２ (OH) ｚ A・nH ２ O ・・・(1) (wherein 2.0≦x≦5.0, 0<y<4.0, 3<(x+y)<6, ((x+y)×2)+4≧z, 0≦n<8) A is CO ３ ２－ , SO ４ ２－ , Cl － , NO ３ ― , PO ４ ３－ at least one selected from the group consisting of.

2. The resin composition according to claim 1, further comprising 1 to 5 parts by weight of hydrotalcite represented by formula (2). Mg ｐ Al ２ (OH) ｑ B・mH ２ O ... (2) (where p ≤ 6, q ≤ (2p + 4), 0 ≤ m ≤ 6) B is CO ３ ２－ , SO ４ ２－ , Cl － NO ３ ― , PO ４ ３－ At least one selected from the following.

3. The resin composition according to claim 1, further comprising aluminum hydroxide and / or magnesium hydroxide.

4. The resin composition according to claim 1, wherein the hydrotalcite has an endothermic peak temperature of at least 190 to 230 as determined by TG-DTA analysis.

5. The resin composition according to claim 1, wherein the resin contains a brominated flame retardant or a halogenated flame retardant.

6. The resin composition according to claim 1, wherein the resin is a vinyl chloride resin or a polyolefin resin.

7. The resin composition according to any one of claims 1 to 6, wherein the specific optical density (Ds at 4.0 min) measured in accordance with the ASTM E662 test method is 100 or less after 4.0 minutes from the start of combustion.

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