Resin composition and molded body

Abstract

The purpose of the present invention is to provide a resin composition excellent in flame retardancy and long-term flame retardancy (for example, flame retardancy after long-term thermal aging at 140°C for 500 hours), while maintaining physical properties such as deflection temperature under load and impact strength. The resin composition according to the present invention comprises (a) a polyphenylene ether-based resin and (b) a phosphoric acid ester-based flame retardant represented by formula (I), wherein the content of the polyphenylene ether-based resin (a) is 40-80 mass% based on 100 mass% of the total mass of all polymer components and the phosphoric acid ester-based flame retardant (b) contained in the resin composition.

Description

Resin composition and molded article

[0001] The present invention relates to resin compositions and molded articles.

[0002] Polyphenylene ether resins are widely used in home appliances, office automation equipment, and automotive parts due to their excellent electrical insulation properties, as well as heat resistance, hydrolysis resistance, and flame retardancy. Materials used in these applications require high flame retardancy due to fire safety concerns, and polyphenylene ether resins achieve this flame retardancy by adding phosphorus compounds without the need for halogen compounds, thus increasing their value from a safety perspective.

[0003] In recent years, with the increasing performance of components, long-term performance is required in addition to short-term performance. Polyphenylene ether resins are required to maintain their mechanical strength and flame retardancy when exposed to high-temperature environments for extended periods. However, polyphenylene ether resins have had the problem of losing their flame retardancy when exposed to high-temperature environments for long periods.

[0004] To address these challenges, techniques are known that involve incorporating specific hydrogenated block copolymers and specific flame retardants in specific compositions, and further utilizing specific manufacturing methods (Patent Document 1), as well as techniques that stabilize polyphenylene ether ends by adding vinyl compounds (Patent Document 2).

[0005] Patent No. 5704936 Patent No. 2925646

[0006] The above-mentioned polyphenylene ether-based resin composition exhibits excellent flame retardancy, but in recent years, there has been a growing demand for even better performance in flame retardancy after high-temperature, long-term heat aging, such as 500 hours or more at 140°C. Furthermore, a challenge has been that adding excessive amounts of flame retardant in anticipation of a decrease in flame retardancy after heat aging can reduce the mechanical properties of the resin composition, such as the temperature of deflection under load and impact strength.

[0007] Therefore, the present invention aims to provide a resin composition that has high flame retardancy even after long-term thermal aging.

[0008] As a result of diligent research to solve the above problems, the present inventors have revealed that by using a phosphate ester-based flame retardant having a specific chemical structure and a polyphenylene ether-based resin in a specific mass ratio, it is possible to provide a composition that is excellent in impact strength and load deflection temperature, and, surprisingly, maintains its flame retardancy even when exposed to high temperatures for a long period of time.

[0009] In other words, the present invention is as follows: [1] A resin composition comprising (a) a polyphenylene ether resin and (b) a phosphate ester flame retardant represented by the following formula (I), wherein the content of the (a) polyphenylene ether resin is 40 to 80% by mass relative to 100% by mass of the total polymer components and the phosphate ester flame retardant contained in the resin composition. (In formula (I), Q １ Q ２ Q ３ , and Q ４ Each of these independently represents an alkyl group having 1 to 6 carbon atoms, and R １represents a methyl group. n1 is an integer from 0 to 2, and m1, m2, m3, and m4 independently represent integers from 0 to 3. n is an integer of 1 or more, and the weight-average degree of condensation N calculated by excluding the component n=0 has 1.00 ≤ N ≤ 1.40.) [2] The resin composition according to [1], further comprising (c) a polystyrene resin. [3] The resin composition according to [2], wherein the mass ratio of the (a) polyphenylene ether resin and the (c) polystyrene resin is (a):(c) = 50:50 to 90:10. [4] The resin composition according to any one of [1] to [3], further comprising (d) an elastomer. [5] The resin composition according to any one of [1] to [4], wherein the (b) phosphate ester flame retardant is n1=0 and m1, m2, m3, and m4 are 0. [6] The resin composition according to any one of [1] to [5], wherein the weight-average degree of condensation N of the (b) phosphate ester flame retardant, calculated by excluding the component with n=0, is 1.00 ≤ N ≤ 1.10. [7] The resin composition according to any one of [1] to [6], wherein the proportion of the component in the (b) phosphate ester flame retardant having a weight-average degree of condensation N of 1 is 90% by mass or more. [8] The resin composition according to [2], wherein the mass ratio of the (b) phosphate ester flame retardant to 100 parts by mass of the total of the (a) polyphenylene ether resin and the (c) polystyrene resin is 5 to 25 parts by mass. [9] The resin composition according to any one of [1] to [8], wherein the difference between the average burning time Ta measured based on the UL-94 vertical combustion test without heat aging of a 0.75 mm thick UL-94 vertical combustion test measurement test piece made of the resin composition and the average burning time Tb measured based on the UL-94 vertical combustion test after heat aging of a 0.75 mm thick UL-94 vertical combustion test measurement test piece made of the resin composition at 140°C for 500 hours is 2.5 seconds or less.

[10] A molded article characterized by comprising the resin composition according to any one of [1] to [9].

[0010] According to the present invention, it is possible to provide a resin composition that has high flame retardancy even after long-term thermal aging.

[0011] Hereinafter, a mode for implementing the resin composition of the present invention (hereinafter, also referred to as "this embodiment") will be described in detail. The present invention is not limited to the following embodiments, and can be implemented with various modifications within the scope of the gist. In addition, in this specification, the flame retardancy after long-term thermal aging, which is an effect of the present invention, may be referred to as "long-term flame retardancy".

[0012] The resin composition of this embodiment contains (a) a polyphenylene ether resin and (b) a phosphate ester flame retardant represented by the following formula (I), and the content of the (a) polyphenylene ether resin with respect to the total mass of 100% by mass of all polymer components and the above-mentioned (b) phosphate ester flame retardant contained in the resin composition is 40 to 80% by mass. (In formula (I), Q １ , Q ２ , Q ３ , and Q ４ each independently represents an alkyl group having 1 to 6 carbon atoms, and R １ represents a methyl group. n1 represents an integer of 0 to 2, and m1, m2, m3, and m4 independently represent an integer of 0 to 3. n is an integer of 1 or more, and the weight average degree of condensation N calculated excluding the component with n = 0 has 1.00 ≦ N ≦ 1.40.) The resin composition of this embodiment may be a composition consisting only of the (a) component and the (b) component, or may be a composition consisting only of the (a) component, the (b) component, and the (c) component, or may be a composition consisting only of the (a) component, the (b) component, and the (d) component, or may be a composition consisting only of the (a) component, the (b) component, the (c) component, and the (d) component, and may further contain other components (for example, other flame retardants and additives described later). In this specification, the above-mentioned (a) polyphenylene ether resin may be referred to as the "(a) component", the above-mentioned (b) phosphate ester flame retardant may be referred to as the "(b) component", the above-mentioned (c) polystyrene resin may be referred to as the "(c) component", and the above-mentioned (d) elastomer may be referred to as the "(d) component".

[0013] - (a) Polyphenylene ether resin (component (a)) - As component (a) in the resin composition of this embodiment, either a homopolymer consisting only of the structural units of general formula (II) below, or a copolymer having the structural units of general formula (II) (hereinafter sometimes simply referred to as "polyphenylene ether") can be used. In general formula (II), O is an oxygen atom, and R １ ~R ４ This independently represents one selected from the group consisting of a hydrogen atom, a halogen atom, a primary or secondary C1-C8 alkyl group, a phenyl group, a haloalkyl group, an aminoalkyl group, a hydrocarbon oxy group, and a halohydrocarbon oxy group (where at least two carbon atoms separate the halogen atom and the oxygen atom). The structural unit of general formula (II) contained in component (a) above may be one type or a combination of multiple types.

[0014] (a) Examples of polyphenylene ether homopolymers include, but are not limited to, poly(2,6-dimethyl-1,4-phenylene ether), poly(2-methyl-6-ethyl-1,4-phenylene ether), poly(2-methyl-6-phenyl-1,4-phenylene ether), and poly(2,6-dichloro-1,4-phenylene ether).

[0015] (a) Examples of copolymers of polyphenylene ether resins include, but are not limited to, copolymers of 2,6-dimethylphenol with other phenols (for example, copolymers with 2,3,6-trimethylphenol, copolymers with 2-methyl-6-butylphenol, and copolymers with 3-methyl-6-t-butylphenol).

[0016] Among these, (a) as polyphenylene ether resins, poly(2,6-dimethyl-1,4-phenylene ether), copolymers of 2,6-dimethylphenol and 2,3,6-trimethylphenol, or mixtures thereof are preferred from the viewpoint of balance of mechanical properties and productivity.

[0017] The method for producing the (a) polyphenylene ether resin used in this embodiment is not limited to the following, but examples include known production methods described in U.S. Patent No. 3,306,874, No. 3,306,875, No. 3,257,357, No. 3,257,358, Japanese Unexamined Patent Publication No. 50-51197, Japanese Patent Publication No. 52-17880, Japanese Unexamined Patent Publication No. 63-152628, etc.

[0018] (a) The reduced viscosity of the polyphenylene ether resin is preferably in the range of 0.25 to 0.70 dL / g from the viewpoint of balancing fluidity and impact strength. More preferably, the reduced viscosity is in the range of 0.30 to 0.65 dL / g, and even more preferably in the range of 0.40 to 0.60 dL / g. If the reduced viscosity is 0.25 dL / g or higher, the composition has excellent impact strength. If the reduced viscosity is 0.65 dL / g or lower, the fluidity is excellent. In this embodiment, the reduced viscosity of (a) the polyphenylene ether resin is the value measured in a 0.5 g / dL chloroform solution at 30°C using an Ubbelohde type viscosity tube. In this embodiment, a mixture of two or more polyphenylene ether resins with different reduced viscosities can also be preferably used.

[0019] Furthermore, the polyphenylene ether resin (a) of this embodiment may contain a modified polyphenylene ether that is modified in whole or in part. The modified polyphenylene ether referred to herein is a polyphenylene ether modified with a modified compound (hereinafter sometimes simply referred to as "modified compound") which has at least one carbon-carbon double or triple bond in its molecule and at least one group selected from the group consisting of a carboxylic acid group, an acid anhydride group, an amino group, a hydroxyl group, and a glycidyl group. Only one type of modified compound may be used, or two or more types may be used in combination.

[0020] Methods for producing modified polyphenylene ether are not limited to the following, but include, for example, (1) a method of reacting a modified compound with a polyphenylene ether at a temperature of 100°C or higher but below the glass transition temperature of the polyphenylene ether, (2) a method of melt-kneading and reacting a modified compound with a polyphenylene ether at a temperature of 360°C or higher but above the glass transition temperature of the polyphenylene ether, and (3) a method of reacting a polyphenylene ether with a modified compound in solution at a temperature below the glass transition temperature of the polyphenylene ether. Among these methods for producing modified polyphenylene ether, method (1) or (2) is preferred from the viewpoint of productivity.

[0021] Next, the modified compounds used to produce modified polyphenylene ethers will be described. The modified compounds used to produce modified polyphenylene ethers are modified compounds that have at least one carbon-carbon double or triple bond in their molecule, and at least one group selected from the group consisting of a carboxylic acid group, an acid anhydride group, an amino group, a hydroxyl group, and a glycidyl group.

[0022] Modified compounds having a carbon-carbon double bond in the molecule and a carboxylic acid group or an acid anhydride group are not limited to the following, but examples include unsaturated dicarboxylic acids such as maleic acid, fumaric acid, chloromaleic acid, cis-4-cyclohexene-1,2-dicarboxylic acid, and their acid anhydrides. In particular, from the viewpoint of reactivity with polyphenylene ether resins, fumaric acid, maleic acid, and maleic anhydride are preferred as modified compounds, and fumaric acid and maleic anhydride are more preferred.

[0023] Furthermore, compounds in which one or two of the two carboxyl groups of the above-mentioned unsaturated dicarboxylic acid are esterified can also be used as modified compounds.

[0024] Examples of the modified compound having a carbon-carbon double bond and a glycidyl group in the molecule include, but are not limited to, allyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate, epoxidized natural oils, etc. Among these, glycidyl acrylate and glycidyl methacrylate are preferred.

[0025] Examples of the modified compound having a carbon-carbon double bond and a hydroxy group in the molecule include, but are not limited to, allyl alcohol, 4-penten-1-ol, 1,4-pentadien-3-ol, etc., unsaturated alcohols of the general formula C ｎ H ２ｎ－１ OH, C ｎ H ２ｎ－３ OH (where n is a positive integer), unsaturated alcohols of the general formula C ｎ H ２ｎ－５ OH, C ｎ H ２ｎ－７ OH (where n is a positive integer), etc.

[0026] The above-mentioned modified compounds may be used alone or in combination of two or more.

[0027] From the viewpoint of modification efficiency, for example, the addition amount of the modified compound in the production of the modified polyphenylene ether is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 5 parts by mass, and still more preferably 0.5 to 3 parts by mass with respect to 100 parts by mass of the polyphenylene ether.

[0028] From the viewpoints of the modification rate and the balance of physical properties, the addition amount of the radical initiator in the production of the modified polyphenylene ether using the radical initiator is preferably 0.001 to 1 part by mass, more preferably 0.01 to 0.5 part by mass, and still more preferably 0.05 to 0.3 part by mass with respect to 100 parts by mass of the polyphenylene ether.

[0029] Further, the addition rate of the modified compound to the modified polyphenylene ether is preferably 0.01 to 5% by mass, more preferably 0.05 to 3% by mass, and still more preferably 0.1 to 1% by mass with respect to 100% by mass of the modified polyphenylene ether.

[0030] Unreacted modified compounds and polymers of modified compounds may remain in the modified polyphenylene ether. The amount of unreacted modified compounds and polymers of modified compounds remaining is preferably less than 5% by mass, more preferably 3% by mass or less, and even more preferably 1% by mass or less.

[0031] The above-mentioned polyphenylene ether is generally available as a powder, and the particle size is preferably 1 to 1000 μm in weight-average particle diameter, more preferably 10 to 700 μm, and particularly preferably 100 to 500 μm. From the viewpoint of handling during processing, 1 μm or more is preferred, and 1000 μm or less is preferred in order to suppress the generation of unmelted material during molten mixing. In this specification, weight-average particle diameter refers to the value obtained by sieving for 30 minutes using a micro-type electromagnetic vibrating sieve (10 mesh stages with mesh openings from 1700 μm to 46 μm) and calculating the 50% diameter of the weight-cumulative particle size distribution.

[0032] - (b) Phosphate ester flame retardant (component (b)) - The resin composition of this embodiment contains a phosphate ester flame retardant having the following structure as component (b). In general formula (I), Q １ Q ２ Q ３ , and Q ４ Each of these independently represents an alkyl group having 1 to 6 carbon atoms, and R １represents a methyl group. n1 is an integer from 0 to 4 (preferably an integer from 0 to 2), and m1, m2, m3, and m4 independently represent integers from 0 to 3. n is an integer of 1 or more, and the weight-average degree of condensation N calculated by excluding the component n=0 preferably has a range of 1.00 ≤ N ≤ 1.40, and being within this range tends to result in excellent fluidity, impact strength, and long-term flame retardancy. The above weight-average degree of condensation N is more preferably 1.00 ≤ N ≤ 1.10. Here, the weight-average degree of condensation N can be determined by known methods by analyzing (b) the phosphate ester flame retardant itself or (b) the phosphate ester flame retardant extracted from the composition by liquid chromatography (LC) or gel permeation chromatography (GPC). In particular, with respect to long-term flame retardancy, it is thought that the smaller the weight-average degree of polymerization, the greater the plasticizing effect of the polyphenylene ether resin, and therefore the more effectively the oxidative crosslinking of the polyphenylene ether resin, which is a factor in the deterioration of long-term flame retardancy, can be suppressed. However, even if the effects of the present invention are achieved for other reasons, they are still within the technical scope of the present invention. Examples of preferred general formula (I) include compounds where n1 = 0 and m1, m2, m3, and m4 are 0, and compounds where m1, m2, m3, m4, and n1 are 0 and 1.00 ≤ N ≤ 1.40. Another example is a compound where m1, m2, m3, and m4 are 1, and Q １ Q ２ Q ３ Q ４ The group is a methyl group, n1 is 0, and 1.00 ≤ N ≤ 1.40. Another example is when m1, m2, m3, m4 are 2, and Q １ Q ２ Q ３ Q ４(b) is a methyl group, n1 is 0, and 1.00 ≤ N ≤ 1.40. When the components of (b) are these, (a) the compatibility with polyphenylene ether resins is excellent, and the fluidity, impact strength and long-term flame retardancy tend to be excellent. Of the above (b) phosphate ester flame retardants, it is preferable that the proportion of components with a weight-average degree of condensation N of 1 (N=1) is 90% by mass or more, more preferably 95% by mass or more, and even more preferably 98% by mass or more. By adjusting the proportion of components with N=1 to 90% by mass or more, the plasticizing effect of the resin composition is enhanced, and the long-term flame retardancy can be improved.

[0033] (b) It is believed that the above structure of component (b) effectively suppresses oxidative crosslinking of polyphenylene ether resins, which is a factor in the deterioration of long-term flame retardancy. Furthermore, the high hydrolysis resistance of the flame retardant itself, derived from its chemical structure, also contributes to long-term flame retardancy. It should be noted that the above mechanism is merely speculative, and even if the effects of the present invention are achieved for other reasons, they are still within the technical scope of the present invention.

[0034] The content of component (b) is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 12 parts by mass or more, relative to 100 parts by mass of the total of components (a) and (c). Furthermore, from the viewpoint of heat resistance and impact strength, the upper limit is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less. Furthermore, the mass ratio of the (b) phosphate ester flame retardant having a weight-average degree of condensation N of 1 (N=1) is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 12 parts by mass or more, relative to 100 parts by mass of the total of components (a) and (c). Furthermore, from the viewpoint of heat resistance and impact strength, the upper limit is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less.

[0035] - (c) Polystyrene resin (component (c)) - In this embodiment, (c) polystyrene resin (component (c)) may be included. (c) Polystyrene resin is a copolymer obtained by polymerizing a styrene compound, or a compound copolymerizable with a styrene compound and a compound copolymerizable with a styrene compound (hereinafter, "compound copolymerizable with a styrene compound" may be simply referred to as "copolymerizable compound"), in the presence or absence of a rubbery polymer. The styrene resin that also corresponds to the (d) elastomer described later is component (d) and not component (c).

[0036] The styrene-based compounds mentioned above are not limited to those listed below, but examples include styrene, α-methylstyrene, 2,4-dimethylstyrene, monochlorostyrene, p-methylstyrene, p-tert-butylstyrene, ethylstyrene, and the like. Among these, styrene is preferred as the styrene-based compound.

[0037] Examples of compounds that can copolymerize with styrene compounds (copolymerizable compounds) are, but are not limited to, methacrylic acid esters such as methyl methacrylate and ethyl methacrylate; unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile; and acid anhydrides such as maleic anhydride.

[0038] The amount of copolymerizable compound is preferably 20% by mass or less, and more preferably 15% by mass or less, based on 100% by mass of the total amount of the styrene-based compound and copolymerizable compound.

[0039] Examples of the above-mentioned rubbery polymers include conjugated diene rubbers, copolymers of conjugated dienes and aromatic vinyl compounds, and ethylene-propylene copolymer rubbers. Among these, polybutadiene, styrene-butadiene random copolymers, styrene-butadiene block copolymers, and rubber components obtained by partially, substantially, or completely hydrogenating these (for example, rubber components with a hydrogenation rate of 50 to 100%) are preferred as rubbery polymers.

[0040] (c) Component is not limited to the following, but examples include homopolystyrene, rubber-modified polystyrene (HIPS), styrene-acrylonitrile copolymer (AS resin), styrene-rubbery polymer-acrylonitrile copolymer (ABS resin), and other styrene copolymers. Among these, (c) is preferably one or more selected from the group consisting of homopolystyrene and rubber-modified polystyrene (HIPS) from the viewpoint of compatibility with polyphenylene ether resins.

[0041] The mass ratio of component (a) to component (c) is preferably (a):(c) = 50:50 to 90:10. More preferably (a):(c) = 70:30 to 88:12, even more preferably (a):(c) = 75:25 to 85:15, and even more preferably (a):(c) = 77:23 to 82:18. This content ratio allows component (b) to effectively maintain long-term flame retardancy. In the range where the mass ratio of component (a) to component (c) is lower, oxidative crosslinking of the polyphenylene ether resin is inherently less likely to occur, and the effect of deterioration of flame retardancy due to hydrolysis of the flame retardant becomes dominant, limiting the long-term flame retardancy maintenance effect of component (b). In the range where the content ratio of component (a) to component (c) is higher, oxidative crosslinking of the polyphenylene ether resin proceeds very rapidly, resulting in a region where the oxidative crosslinking suppression by component (b) does not work effectively, and the long-term flame retardancy maintenance effect is limited.

[0042] - (d) Elastomer (component (d)) - The resin composition of this embodiment may further contain (d) elastomer. Including component (d) improves the impact strength of the resin composition. Preferred (d) elastomers are block copolymers of aromatic vinyl compounds (e.g., styrene) and conjugated diene compounds, and more preferably hydrogenated block copolymers obtained by hydrogenating the above block copolymer. As stated above, styrene-based resins among those contained in the elastomer are not included in component (c).

[0043] From the viewpoint of heat stability, the hydrogenation rate of the unsaturated bonds derived from the conjugated diene compound by hydrogenation is preferably 60% or more, more preferably 80% or more, and even more preferably 95% or more.

[0044] The structure of a block copolymer before hydrogenation is such that, if the block copolymer is a block copolymer of styrene and a conjugated diene compound, then, if we represent the styrene block chain as S and the diene compound block chain as B, then for example, S-B-S, S-B-S-B, (S-B-) ４ Examples include -S, S-B-S-B-S, etc. Furthermore, the microstructure of the polymer block of the conjugated diene compound (the bonding configuration of the conjugated diene compound) can be arbitrarily selected. The amount of vinyl bonds in the conjugated diene compound polymer block (total of 1,2-vinyl bonds and 3,4-vinyl bonds) is preferably 2 to 60%, and more preferably 8 to 40%, of the total amount of bonds in the conjugated diene compound polymer (total of 1,2-vinyl bonds, 3,4-vinyl bonds and 1,4-conjugated bonds).

[0045] The number-average molecular weight of component (d) is preferably 100,000 to 400,000, more preferably 150,000 to 350,000, and even more preferably 200,000 to 300,000. When the number-average molecular weight of component (d) is 100,000 or more, the resin composition exhibits superior impact strength. Furthermore, when the number-average molecular weight of component (d) is 400,000 or less, the resin composition exhibits superior fluidity. The above number-average molecular weight is the number-average molecular weight on a polystyrene basis, and specifically, it can be determined using GPC, with chloroform as the solvent and a column temperature of 40°C, from the detection time-molecular weight curve of standard polystyrene measured in advance under the same conditions.

[0046] If component (d) has styrene polymer block chains, it is preferable that the number average molecular weight of at least one styrene polymer block chain is 15,000 or more. More preferably, the number average molecular weight of at least one styrene polymer block chain is 20,000 to 50,000. Even more preferably, the number average molecular weight of all styrene polymer block chains is 15,000 or more.

[0047] If component (d) has styrene polymer block chains, the proportion of component (d) occupied by styrene polymer block chains is not particularly limited as long as the number-average molecular weight of the styrene polymer block chains is within the above range, but from the viewpoint of impact strength, it is preferably 10 to 70% by mass, more preferably 20 to 50% by mass, and even more preferably 30 to 40% by mass.

[0048] (d) Component may also be a combination of two or more hydrogenated block copolymers with different compositions or structures. For example, a combination of a hydrogenated block copolymer with a conjugated styrene polymer block content of 50% by mass or more and a hydrogenated block copolymer with a conjugated styrene polymer block content of 30% by mass or less, a combination of hydrogenated block copolymers with different molecular weights, or a combination of a block copolymer of styrene and a conjugated diene compound as described above and a hydrogenated random block copolymer obtained by hydrogenating a block copolymer containing random copolymer blocks of styrene and a conjugated diene compound. Note that "conjugated styrene polymer block content" refers to the proportion of styrene polymer block chains in component (d).

[0049] (Other Flame Retardants) The resin composition of this embodiment may contain various conventionally known flame retardants and flame retardant additives. Examples of other flame retardants include phosphinates, alkaline earth metal hydroxides such as magnesium hydroxide, aluminum hydroxide, alkali metal hydroxides, zinc borate compounds, zinc stannate compounds, and the like.

[0050] (Additives) In order to impart further properties to the resin composition of this embodiment, other resins other than components (a), (c), and (d), or additives such as plasticizers, antioxidants, stabilizers such as ultraviolet absorbers, antistatic agents, mold release agents, dyes, pigments, fillers, reinforcing agents, and spreading agents may be added, to the extent that they do not impair the effects of the present invention.

[0051] (Composition of the resin composition) The mass ratio of component (a) above to 100% by mass of the resin composition of this embodiment is preferably 40% by mass or more, more preferably 50% by mass or more. It is also preferably 85% by mass or less, more preferably 77% by mass or less. The mass ratio of component (b) above (preferably a (b) phosphate ester flame retardant having a weight-average degree of condensation N of 1) above to 100% by mass of the resin composition of this embodiment is preferably 5% by mass or more, more preferably 7% by mass or more. It is also preferably 30% by mass or less, more preferably 22% by mass or less. The mass ratio of component (c) above to 100% by mass of the resin composition of this embodiment is preferably 5% by mass or more, more preferably 7% by mass or more. It is also preferably 35% by mass or less, more preferably 26% by mass or less. If the resin composition of this embodiment contains component (d) above, the mass ratio of component (d) above to 100% by mass of the resin composition is preferably 1% by mass or more, more preferably 2% by mass or more. Furthermore, it is preferable that the amount be 10% by mass or less, and more preferably 5% by mass or less. The ratio of the total mass of component (a), component (b), component (c), and component (d) to 100% by mass of the resin composition of this embodiment is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. It may also be 100% by mass or less than 100% by mass. In the resin composition of this embodiment, the content of (a) polyphenylene ether resin is 40 to 80% by mass, preferably 50 to 75% by mass, and even more preferably 55 to 70% by mass, based on 100% by mass of the total mass of all polymer components and (b) phosphate ester flame retardant contained in the resin composition. By adjusting the content of (a) polyphenylene ether resin in the total mass of all polymer components and (b) phosphate ester flame retardant contained in the resin composition to the above range, oxidative crosslinking of the polyphenylene ether resin is efficiently suppressed, and long-term flame retardancy is improved.Here, the total polymer components and the (b) phosphate ester-based flame retardant contained in the above resin composition must contain (a) polyphenylene ether resin and (b) phosphate ester-based flame retardant, and if the resin composition contains (c) polystyrene resin and / or (d) elastomer, then (c) polystyrene resin and / or (d) elastomer are also included. Furthermore, the total polymer components and the (b) phosphate ester-based flame retardant contained in the above resin composition also include polymers other than components (a), (c), and (d) that are included as additives. The ratio of the total mass of the total polymer components and the (b) phosphate ester-based flame retardant contained in the above resin composition to 100% by mass of the resin composition of this embodiment is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. It may also be 100% by mass or less than 100% by mass.

[0052] (Characteristics of the Resin Composition) - Influence of Heat Aging on Flame Retardancy - The difference between the average burning time Ta measured based on the UL-94 vertical combustion test without heat aging of a 0.75 mm thick UL-94 vertical combustion test piece made of the resin composition of this embodiment and the average burning time Tb measured based on the UL-94 vertical combustion test after heat aging of the 0.75 mm thick UL-94 vertical combustion test piece made of the resin composition of this embodiment at 140°C for 500 hours is preferably 2.5 seconds or less, more preferably 2.0 seconds or less, and even more preferably 1.5 seconds or less. By making the difference between Ta and Tb 2.5 seconds or less, flame retardancy equivalent to V-0 can be achieved in the UL-94 vertical combustion test of a 0.75 mm thick piece even after long-term heat aging. The average burning time can be measured by the method described in the examples below.

[0053] -Thin-walled flame retardancy- The average burning time Ta measured based on the UL-94 vertical combustion test of a 0.75 mm thick test piece made of the resin composition of this embodiment, without thermal aging, is preferably 5.0 seconds or less, more preferably 4.0 seconds or less, and even more preferably 3.0 seconds or less. The above average burning time Ta can be measured by the method described in the examples below.

[0054] -Long-term flame retardancy- The average burning time Tb measured based on the UL-94 vertical combustion test after a 0.75 mm thick test piece made of the resin composition of this embodiment has been heat-aged at 140°C for 500 hours is preferably 5.0 seconds or less, more preferably 4.0 seconds or less, and even more preferably 3.0 seconds or less. The above average burning time Tb can be measured by the method described in the examples below.

[0055] (Method for producing the resin composition) The resin composition of this embodiment can be produced, for example, by melt-kneading components (a) to (c), and optionally component (d), etc., using a twin-screw extruder.

[0056] Examples of twin-screw extruders include the "ZSK" series from Coperion, the "TEM" series from Toshiba Machine, and the "TEX" series from Japan Steel Works.

[0057] In the method for producing the resin composition of this embodiment, the melt mixing temperature and screw rotation speed can be appropriately selected from the range of 200 to 370°C for the melt mixing temperature and 100 to 1200 rpm for the screw rotation speed.

[0058] Examples of raw material supply devices for supplying raw materials to a twin-screw extruder include loss-in-weight feeders, single-screw feeders, twin-screw feeders, table feeders, and rotary feeders. Among these, loss-in-weight feeders are preferred from the viewpoint of minimizing fluctuations in raw material supply.

[0059] When supplying liquid raw materials, the liquid raw materials can be directly introduced into the cylinder system using a liquid-supply pump or the like to the extruder cylinder section for mixing. The liquid-supply pump is not particularly limited and examples include gear pumps and flange-type pumps. Among these, gear pumps are preferred. Furthermore, it is even more preferable to heat the parts that form the flow path of the liquid raw materials, such as the tank for storing the liquid raw materials used in the liquid-supply pump, the piping between the tank and the pump, and the piping between the pump and the extruder cylinder, using a heater or the like. This reduces the viscosity of the liquid raw materials, thereby reducing the load on the liquid-supply pump, which is preferable from the viewpoint of operability and other factors.

[0060] (Molded article) The molded article of this embodiment contains the resin composition of this embodiment described above. Because the molded article of this embodiment contains the resin composition of this embodiment, it has excellent impact resistance, flame retardancy, and long-term flame retardancy.

[0061] The resin composition of this embodiment can be molded to form a molded article.

[0062] As for the molding method, known molding methods such as injection molding, hollow molding, extrusion molding, sheet molding, and film molding can be used, with injection molding being particularly preferred. As for the injection molding machine, for example, the "PS-40" manufactured by Nissei Plastic Industrial Co., Ltd. can be mentioned.

[0063] In the molding method of the resin composition of this embodiment, the melting temperature and mold temperature can be appropriately selected from the range of 150 to 350°C for the melting temperature and 5 to 150°C for the mold temperature.

[0064] The molded body can be used as a variety of molded parts and is applicable to a wide range of fields, including industrial parts, electrical and electronic components, office equipment housings, automotive parts, and precision parts.

[0065] The following describes this embodiment with reference to specific examples and comparative examples, but this embodiment is not limited to these.

[0066] The raw materials used in the examples and comparative examples, as well as the evaluation and measurement methods for the resin compositions, are shown below.

[0067] <Raw Materials> The raw materials used in the resin compositions of the examples and comparative examples are as follows: • (a) Component poly(2,6-dimethyl-1,4-phenylene ether) (manufactured by Asahi Kasei, trade name "S201A") • (b) Component (b-1): Aromatic condensed phosphate ester compound of the following formula (manufactured by ICL, trade name "Sol-DP", weight-average condensation degree N=1.00, proportion of component with N=1: 99.7% by mass) (b-2): The following aromatic condensed phosphate ester compound (manufactured by Daihachi Chemical Co., Ltd., trade name "CR-741", weight-average degree of condensation N=1.15, proportion of component with N=1: 86.0% by mass) (b-3): The following aromatic condensed phosphate ester compound (manufactured by Daihachi Chemical Co., Ltd., trade name "CR-733S", weight-average degree of condensation N=1.48, proportion of component with N=1: 58.2% by mass) The weight-average condensation degree N and the proportion of components with N=1 in component (b) were calculated as follows. Each condensation degree component in component (b) was separated by liquid chromatography (LC), and the peaks of each condensation degree component were identified by mass spectrometry (MS). The weight-average condensation degree N and the proportion of components with N=1 were determined from the peak area of ​​each. The sample solution was a 10 mg / mL tetrahydrofuran solution of component (b) further diluted with acetonitrile to 20 μg / mL, and the measurement conditions were as follows. Liquid chromatography apparatus: ACQUITY UPLC I-Class (manufactured by Waters Japan Ltd.) Mass spectrometer: microOTOF-QIII (manufactured by Bruker Daltonics Co., Ltd.) Detector: Photodiode array detector (scan range 195 nm to 600 nm) Mass spectrometer column: ACQUITY UPLC BEH C18 (2.1 mm I.D. × 50 mm, 1.7 μm) Column temperature: 50°C Mobile phase A: 10 mmol / L ammonium formate aqueous solution Mobile phase B: Acetonitrile Mobile phase delivery: The concentration gradient is controlled by changing the mixing ratio of mobile phase A and mobile phase B as follows. Mobile phase A 0 min to 4 min 40 → 0 (vol%) Mobile phase B 0 min to 4 min 60 → 100 (vol%) Flow rate: 0.25 mL per minute Injection volume: 1 μL Area measurement range: 4 minutes after sample injection Washing and equilibration: 1. After the analysis is complete, wash by injecting the mobile phase B at a ratio of 100 vol% for 2 minutes, and then equilibrate by further adjusting the mobile phase B ratio to 60 vol%. ・(c) Component: Rubber-modified polystyrene (manufactured by Petrochemical, trade name "CT60") ・(d) Component: Hydrogenated block copolymer (manufactured by TSRC, trade name "TAIPOL6151")

[0068] The equipment used in the example is shown below. Twin-screw extruder: Coperion, product name "ZSK-25WLE" Small injection molding machine: Toshiba Machine, "EC75SXII"

[0069] <Evaluation Method> The resin compositions obtained in the examples and comparative examples were evaluated using the following methods and conditions.

[0070] (Fluidity) Molding fluidity was evaluated by measuring the melt flow rate. The resin composition pellets obtained in the examples and comparative examples were pre-dried at 80°C for 1 hour, and then the melt flow rate (MFR) (g / 10min) was measured in accordance with ISO 1133 at 250°C and 10 kg. A higher measured value indicates better molding fluidity.

[0071] (Impact Strength) Impact strength was evaluated by Charpy impact testing. The resin compositions obtained in the examples and comparative examples were supplied to a screw-type in-line injection molding machine (Toshiba Machine Co., Ltd., "EC75SXII") set to 220-280°C, and test specimens of the dimensions specified in ISO-179 were produced by injection molding under conditions of a mold temperature of 60-80°C. Using these test specimens, the Charpy impact strength (kJ / m²) was measured with notches in accordance with ISO-179. ２ The impact strength was measured. A larger measured value indicates better impact strength.

[0072] (Heat Resistance) The resin compositions obtained in the examples and comparative examples were supplied to a screw-type in-line injection molding machine (Toshiba Machine Co., Ltd., "EC75SXII") set to 220-280°C, and test specimens with dimensions specified in JIS K7191-1 were produced by injection molding under conditions of a mold temperature of 60-80°C. The temperature of deflection under load (°C) was measured using these test specimens in accordance with JIS K7191-1. A higher value indicated better heat resistance.

[0073] (Flame Retardancy) Using the resin composition pellets obtained in the examples and comparative examples, the pellets were supplied to a screw in-line injection molding machine set to 240°C to 320°C, and UL-94 vertical combustion test pieces (0.75 mm thick) were injection molded under conditions of a mold temperature of 90°C. The flame retardancy of the five test pieces molded in this way was evaluated based on the UL-94 vertical combustion test. After 10 seconds of flame contact, the burning time from when the flame was removed until the flame went out was defined as t1 (seconds), and after another 10 seconds of flame contact, the burning time from when the flame was removed until the flame went out was defined as t2 (seconds). For each of the five pieces, the average burning time Ta (seconds) was calculated by combining t1 and t2 over 10 trials.

[0074] (Long-term flame retardancy) Test pieces (0.75 mm thick) for the UL-94 vertical combustion test, obtained by the same method as the flame retardancy test described above, were suspended by clips in a gear oven at 140°C and subjected to thermal aging for 500 hours while being rotated to ensure uniform heating. The damper opening of the gear oven was set to 50% during this time. After thermal aging, the test pieces were removed, and their flame retardancy was evaluated based on the UL-94 vertical combustion test, with t1 and t2 being measured. The average combustion time Tb (seconds) was then calculated by combining t1 and t2 over 10 trials.

[0075] <Preparation of Resin Compositions> (Examples 1-8 and Comparative Examples 1-5) Components (a) to (d) were supplied to a twin-screw extruder in the compositions shown in Table 1, and melt-kneaded under the conditions of an extrusion temperature of 280-320°C, a screw rotation speed of 300 rpm, and a discharge rate of 15 kg / hour to obtain pellets of the resin compositions of each example and comparative example. The twin-screw extruder was configured as follows: it had 12 barrel blocks, and regarding the flow direction of the raw materials, an upstream supply port was provided at the 1st barrel from the upstream end, and vacuum vents were provided at the 5th and 11th barrels. Components (a), (b), (c), and (d) were all supplied from the upstream supply port. The composition and evaluation results of the resin compositions of each example and comparative example prepared are shown in Table 1.

[0076]

[0077] From the results in Table 1, Examples 1 to 8 all exhibited excellent fluidity, impact strength, load deflection temperature, flame retardancy, and long-term flame retardancy, yielding thermoplastic resin compositions applicable to electrical and electronic components, automotive parts, and other applications requiring high heat resistance over long periods. Comparative Examples 1 and 2 compare the performance of resin compositions with Example 1 when component (b) has a structure outside the scope of this claim. In both cases, the long-term flame retardancy is inferior to that of Example 1, and the average burning time is 5 seconds or more, failing to meet the V-0 requirement of the UL-94 standard. Furthermore, the impact strength is also inferior to that of Example 1. Comparative Examples 4 and 5 are resin compositions in which the content ratio of component (a) and component (c) is outside the scope of this claim compared to that of Example 1. In this case, the long-term flame retardancy is significantly inferior to that of Example 1. Comparative Example 3 is a resin composition in which component (b) has a structure outside the scope of this claim and the content ratio of component (a) and component (c) is outside the scope of this claim. In this case, Comparative Example 3 has inferior long-term flame retardancy compared to Example 1, and therefore neither can be suitably used in applications requiring high heat resistance over a long period of time. Thus, it can be seen that when component (b) is within the scope of this claim and the mass ratio of (a) polyphenylene ether resin to the total mass of all polymer components and the above-mentioned (b) phosphate ester flame retardant contained in the resin composition is within the scope of this claim, a resin composition that can be suitably used in electrical and electronic components, automotive parts, etc., that specifically require high heat resistance over a long period of time can be obtained.

Claims

1. A resin composition comprising (a) a polyphenylene ether resin and (b) a phosphate ester flame retardant represented by the following formula (I), wherein the content of (a) the polyphenylene ether resin is 40 to 80% by mass relative to 100% by mass of the total polymer components and the phosphate ester flame retardant contained in the resin composition. (In formula (I), Q １ Q ２ Q ３ , and Q ４ Each of these independently represents an alkyl group having 1 to 6 carbon atoms, and R １ represents a methyl group. n1 is an integer between 0 and 2, and m1, m2, m3, and m4 independently represent integers between 0 and 3. n is an integer greater than or equal to 1, and the weight-average degree of condensation N calculated excluding the component n=0 has a range of 1.00 ≤ N ≤ 1.

40.

2. The resin composition according to claim 1, further comprising (c) a polystyrene resin.

3. The resin composition according to claim 2, wherein the mass ratio of (a) polyphenylene ether resin to (c) polystyrene resin is (a):(c) = 50:50 to 90:

10.

4. The resin composition according to claim 1, further comprising (d) an elastomer.

5. The resin composition according to claim 1, wherein the (b) phosphate ester flame retardant is n1 = 0 and m1, m2, m3, and m4 are 0.

6. The resin composition according to claim 1, wherein the weight-average degree of condensation N of the phosphate ester flame retardant, calculated by excluding the component n=0, is 1.00 ≤ N ≤ 1.

10.

7. The resin composition according to claim 1, wherein the proportion of the phosphate ester flame retardant (b) having a weight-average degree of condensation N of 1 is 90% by mass or more.

8. The resin composition according to claim 2, wherein the mass ratio of (b) phosphate ester flame retardant to 100 parts by mass of the total of (a) polyphenylene ether resin and (c) polystyrene resin is 5 to 25 parts by mass.

9. The resin composition according to claim 1, wherein the difference between the average burning time Ta measured based on the UL-94 vertical combustion test without thermal aging of a 0.75 mm thick UL-94 vertical combustion test measurement test piece made of the resin composition and the average burning time Tb measured based on the UL-94 vertical combustion test after thermal aging of a 0.75 mm thick UL-94 vertical combustion test measurement test piece made of the resin composition at 140°C for 500 hours is 2.5 seconds or less.

10. A molded article characterized by comprising the resin composition described in any one of claims 1 to 9.

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