Resin composition and molded article

Abstract

To provide a resin composition comprising a polyamide resin, a reinforcement fiber and a phosphorus-based flame retardant, which is excellent in fire retardancy while maintaining high mechanical strength inherently possessed by the resin composition and to provide a molded article of the same.SOLUTION: There is provided a resin composition which comprises (A) 28.0 to 50.0 mass% of a semi-aromatic polyamide resin, (B) 35.0 to 60.0 mass% of a reinforcement fiber, (C) 1.0 mass% or more and less than 10.0 mass% of a phosphorus-based flame retardant, (D) 0.1 to 10.0 mass% of a hydrous metal salt having a dehydration temperature higher by 100°C or more than the melting point of the semi-aromatic polyamide resin (A) according to the differential scanning calorimetry and (E) 0 to 25.0 mass% of at least one additive other than the above and the total of the components (A) to (E) is defined as 100.0 mass%, wherein the content of an aliphatic polyamide resin is less than 1.0 mass% of the resin composition.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin composition and a molded article.

Background Art

[0002] Since polyamide resins have excellent mechanical strength, they are applied in various fields. On the other hand, in applications such as automotive parts, aircraft parts, and mobile terminals, the requirement for flame retardancy is increasing more and more. This is not an exception for polyamide resins either, and further improvement in flame retardancy is required while maintaining mechanical strength.

[0003] Patent Document 1 discloses a flame-retardant resin composition containing (A) a polyamide resin, (B) a phosphorus-based flame retardant, and (C) glass fibers having a non-circular cross section, wherein the contents in the composition are, respectively, (A) the polyamide resin is 15 to 78% by weight, (B) the phosphorus-based flame retardant is 2 to 20% by weight, and (C) the glass fibers having a non-circular cross section is 20 to 65% by weight. Also, Patent Document 2 discloses a flame-retardant polyamide resin composition containing (a) about 20 to about 90% by weight of an aromatic polyamide derived from about 5 to about 75 mole percent of an aromatic monomer, (b) a flame retardant containing a phosphinate of formula (I), and / or a bisphosphinate of formula (II), and / or a polymer thereof in an amount of about 10 to about 40% by weight, (c) an inorganic reinforcing agent and / or a filler in an amount of 0 to about 60% by weight, and (d) at least one synergist in an amount of 0 to about 10% by weight, wherein the above-described percentages are based on the total weight of the composition.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described above, a resin composition obtained by blending a polyamide resin with a flame retardant and reinforcing fibers is known. However, when a flame retardant is blended with a polyamide resin, even if reinforcing fibers are blended, the mechanical strength that is originally achieved tends to decrease, and further studies are required. An object of the present invention is to solve such problems, and to provide a resin composition containing a polyamide resin, reinforcing fibers, and a phosphorus-based flame retardant, which maintains the high mechanical strength inherent to the resin composition and has excellent flame retardancy, and a molded article thereof.

Means for Solving the Problems

[0006] As a result of studies by the present inventors under the above problems, it has been found that the above problems can be solved by blending a polyamide resin with a reinforcing fiber, a phosphorus-based flame retardant, and a hydrous metal salt having a dehydration temperature 100 °C or higher than the melting point according to the differential scanning calorimetry of the (A) semi-aromatic polyamide resin. Specifically, the above problems have been solved by the following means. <1> A resin composition comprising (A) 28.0 to 50.0% by mass of a semi-aromatic polyamide resin, (B) 35.0 to 60.0% by mass of reinforcing fibers, (C) 1.0% by mass or more and less than 10.0% by mass of a phosphorus-based flame retardant, (D) 0.1 to 10.0% by mass of a hydrous metal salt having a dehydration temperature 100 °C or higher than the melting point according to the differential scanning calorimetry of the (A) semi-aromatic polyamide resin, and (E) 0 to 25.0% by mass of at least one additive other than the above, with the total of components (A) to (E) being 100.0% by mass, and the content of the aliphatic polyamide resin being less than 1.0% by mass of the resin composition. <2> The resin composition according to <1>, wherein the (C) phosphorus-based flame retardant contains at least one of phosphinates and diphosphinates. <3>The (A) semi-aromatic polyamide resin-containing resin composition according to <1> or <2>, which contains a structural unit having a linear aliphatic chain with 4 to 7 carbon atoms. <4>The resin composition according to any one of <1> to <3>, wherein the (D) hydrous metal salt contains boehmite. <5>The resin composition according to any one of <1> to <4>, wherein the (B) reinforcing fiber contains glass fiber. <6>The resin composition according to any one of <1> to <5>, wherein the (C) phosphorus-based flame retardant contains at least one compound represented by the following formula (I) and a compound represented by formula (II).

Chemical formula

Chemical formula

Advantages of the Invention

[0007] According to the present invention, there is provided a resin composition containing a polyamide resin, a reinforcing fiber, and a phosphorus-based flame retardant, which maintains the high mechanical strength inherent in the resin composition and has excellent flame retardancy, and a molded article thereof.

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. The following present embodiment is an exemplification for explaining the present invention, and the present invention is not limited to the present embodiment only. In this specification, "~" is used in the sense of including the numerical values described before and after it as the lower limit value and the upper limit value. In this specification, various physical property values and characteristic values are those at 23°C unless otherwise specified. When the standards shown in this specification differ depending on the year and the measurement method, etc., they are based on the standards as of January 1, 2021 unless otherwise specified.

[0009] The resin composition of this embodiment comprises (A) 28.0 to 50.0% by mass of a semi-aromatic polyamide resin, (B) 35.0 to 60.0% by mass of a reinforcing fiber, (C) 1.0% by mass or more and less than 10.0% by mass of a phosphorus-based flame retardant, (D) 0.1 to 10.0% by mass of a hydrated metal salt having a dehydration temperature 100 °C or higher than the melting point according to differential scanning calorimetry of (A) the semi-aromatic polyamide resin, and (E) 0 to 25.0% by mass of at least one additive other than the above, with the total of components (A) to (E) being 100.0% by mass, and is characterized in that the content of the aliphatic polyamide resin is less than 1.0% by mass of the resin composition. By adopting such a configuration, a resin composition excellent in flame retardancy can be obtained while maintaining the high mechanical strength inherent in a resin composition containing a polyamide resin, a reinforcing fiber, and a phosphorus-based flame retardant. Furthermore, by adjusting the amount of the hydrated metal salt to some extent, ejection of gas from the nozzle and the like can also be suppressed.

[0010] In this embodiment, a hydrated metal salt having a dehydration temperature 100 °C or higher than the melting point according to differential scanning calorimetry of (A) the semi-aromatic polyamide resin is used. When a hydrated metal salt that dehydrates by such heat is blended into the polyamide resin, it is presumed that water is released by the heat during combustion of the polyamide resin, and the released water exerts an effect of enhancing the flame retardancy of the polyamide resin. However, heat is also applied to the polyamide resin during processing or molding. That is, it is presumed that the hydrated metal salt may be dehydrated by the heat during heating or molding. Such water is presumed to cause a decrease in the mechanical strength of the molded product. In this embodiment, by using a hydrated metal salt having a dehydration temperature 100 °C or higher than the melting point according to differential scanning calorimetry of (A) the semi-aromatic polyamide resin, it is presumed that water is not released during processing or molding of the polyamide resin, and can be adjusted to release water during combustion. Therefore, it is presumed that a resin composition excellent in flame retardancy can be provided while maintaining high mechanical strength.

[0011] <(A) Semi-aromatic polyamide resin> The resin composition of the present embodiment contains 28.0 to 50.0% by mass of a semi-aromatic polyamide resin (A) in a resin composition in which the total of the above (A) to (E) is 100.0% by mass. The semi-aromatic polyamide resin means that it contains a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, and 30 to 70 mol% (preferably 40 to 60 mol%) of the total structural units of the structural unit derived from diamine and the structural unit derived from dicarboxylic acid are structural units containing an aromatic ring. By using such a semi-aromatic polyamide resin, the mechanical strength of the obtained molded product can be increased.

[0012] The semi-aromatic polyamide resin used in the present embodiment preferably contains a structural unit having a linear aliphatic chain with 4 to 7 carbon atoms. By having such a chain, the flame retardancy of the obtained molded product tends to be further improved. The linear aliphatic chain with the number of carbon atoms is more preferably an α,ω-linear aliphatic chain. Further, the aliphatic chain with 4 to 7 carbon atoms is preferably an aliphatic chain with 4 to 6 carbon atoms, and more preferably -(CH2)4-. The aliphatic chain with 4 to 7 carbon atoms is preferably a part of the structural unit derived from dicarboxylic acid. The ratio of the structural unit (monomer unit) having an aliphatic chain with 4 to 7 carbon atoms is preferably 10 mol% or more, more preferably 20 mol% or more, further preferably 30 mol% or more, still more preferably 40 mol% or more, with the total amount of the structural units (all monomer units) in the semi-aromatic polyamide resin being 100 mol%. The upper limit is preferably 70 mol% or less, more preferably 50 mol% or less.

[0013] In the semi-aromatic polyamide resin according to the preferred embodiment of the present embodiment, the proportion of the structural unit having an aliphatic chain with 4 to 7 carbon atoms in the structural unit derived from dicarboxylic acid is preferably 60 mol% or more, more preferably 75 mol% or more, further preferably 90 mol% or more, still more preferably 95 mol% or more, even more preferably 98 mol% or more, and still even more preferably 99 mol% or more. By adopting such a configuration, the flame retardancy tends to be further improved.

[0014] Examples of the semi-aromatic polyamide resin used in this embodiment include polyamide 4T, 6I, 6T, 6T / 6I, 6 / 6T, 66 / 6T, 66 / 6T / 6I, MXD6, MP6, etc. Here, the above "I" represents an isophthalic acid component, and "T" represents a terephthalic acid component.

[0015] The semi-aromatic polyamide resin used in this embodiment contains a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, and preferably 70 mol% or more of the structural unit derived from the diamine is derived from xylylenediamine. Hereinafter, such a semi-aromatic polyamide resin may be referred to as a xylylenediamine-based polyamide resin. The structural unit derived from dicarboxylic acid of the xylylenediamine-based polyamide resin preferably contains an aliphatic chain having 4 to 7 carbon atoms.

[0016] In the xylylenediamine-based polyamide resin, it is preferable to use meta-xylylenediamine and / or para-xylylenediamine as the xylylenediamine. In this embodiment, the xylylenediamine is preferably only meta-xylylenediamine or a mixture (copolymer) of meta-xylylenediamine and para-xylylenediamine. The molar ratio of meta-xylylenediamine to para-xylylenediamine in xylylenediamine is preferably 100:0 to 10:90, more preferably 95:5 to 15:85, still more preferably 90:10 to 50:50, and even more preferably 80:20 to 60:40. Preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, even more preferably 95 mol% or more, and even more preferably 98 mol% or more of the structural unit derived from diamine of the xylylenediamine-based polyamide resin is derived from xylylenediamine.

[0017] Examples of diamines other than xylylenediamine that can be used as the diamine component of the raw material for xylylenediamine-based polyamide resins include aliphatic diamines such as tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, and 2,4,4-trimethylhexamethylenediamine; alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminomethyl)decalin, and bis(aminomethyl)tricyclodecane; and diamines having an aromatic ring such as bis(4-aminophenyl)ether, paraphenylenediamine, and bis(aminomethyl)naphthalene. One or more of them can be mixed and used.

[0018] The structural units derived from dicarboxylic acids of xylylenediamine-based polyamide resins are preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, even more preferably 95 mol% or more, and yet even more preferably 98 mol% or more, and are derived from α,ω-linear aliphatic dicarboxylic acids having 6 to 9 carbon atoms (preferably adipic acid).

[0019] Preferred as the raw material dicarboxylic acid component for xylylenediamine-based polyamide resins are pimelic acid, suberic acid, adipic acid, and azelaic acid, more preferably adipic acid. One or more of them can be mixed and used, and among them, adipic acid is preferred.

[0020] In addition, examples of dicarboxylic acids other than the above-mentioned dicarboxylic acids include phthalic acid compounds such as isophthalic acid, terephthalic acid, and orthophthalic acid; naphthalenedicarboxylic acids such as 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid. One kind or a mixture of two or more kinds can be used.

[0021] The semi-aromatic polyamide resin used in this embodiment has structural units derived from diamine and structural units derived from dicarboxylic acid as main components, but it does not exclude the inclusion of other structural units. Needless to say, it may contain structural units derived from lactams such as ε-caprolactam and laurolactam, and aliphatic aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid. Here, the main component means that among the structural units constituting the semi-aromatic polyamide resin, the total number of the structural units derived from diamine and the structural units derived from dicarboxylic acid is the largest among all the structural units. In this embodiment, the total of the structural units derived from diamine and the structural units derived from dicarboxylic acid in the semi-aromatic polyamide resin preferably accounts for 90.0% by mass or more, and more preferably 95.0% by mass or more of all the structural units.

[0022] The melting point of the semi-aromatic polyamide resin used in the resin composition of this embodiment is preferably 200°C or higher, and preferably 300°C or lower. By using such a semi-aromatic polyamide resin, the mechanical strength and flame retardancy tend to be more effectively improved.

[0023] The semi-aromatic polyamide resin used in the resin composition of this embodiment preferably has a lower limit of number average molecular weight (Mn) of 6,000 or more, more preferably 8,000 or more, still more preferably 10,000 or more, even more preferably 15,000 or more, and yet even more preferably 20,000 or more. The upper limit of the above Mn is preferably 35,000 or less, more preferably 30,000 or less, and still more preferably 28,000 or less.

[0024] In this embodiment, a preferred form of the semi-aromatic polyamide resin includes a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, and 90 mol% or more of the structural unit derived from diamine is derived from xylylenediamine, and xylylenediamine is a mixture of metaxylylenediamine and paraxylylenediamine, and the molar ratio (M:P) thereof is 80:20 to 60:40, and 90 mol% or more of the structural unit derived from dicarboxylic acid is a structural unit derived from adipic acid, and it is a form mainly composed of a polyamide resin. In the first embodiment, it is preferable that the polyamide resin occupies 90.0 mass% or more of the polyamide resin contained in the resin composition of this embodiment, more preferably 95.0 mass% or more, and still more preferably 99.0 mass% or more. The polyamide resin may contain only one kind or two or more kinds. When two or more kinds are contained, the total amount is within the above range.

[0025] The resin composition of this embodiment contains 28.0 to 50.0 mass% of a semi-aromatic polyamide resin in a resin composition in which the total of the above (A) to (E) is 100.0 mass%. By setting it to be not less than the lower limit value, there is a tendency to suppress the bleed-out of the filler and the additive while maintaining the mechanical properties and flame retardancy. Further, by setting it to be not more than the upper limit value, the mechanical properties and flame retardancy tend to be improved. In the resin composition of the present embodiment, the proportion of the semi-aromatic polyamide resin has a lower limit of 30.0 mass% or more, preferably 32.0 mass% or more, and more preferably 34.0 mass% or more. The upper limit of the proportion of the semi-aromatic polyamide resin is preferably 45.0 mass% or less, and more preferably 40.0 mass% or less. The resin composition of the present embodiment may contain only one kind of semi-aromatic polyamide resin, or may contain two or more kinds. When two or more kinds are contained, it is preferable that the total amount is within the above range.

[0026] In the resin composition of the present embodiment, the content of the aliphatic polyamide resin is less than 1.0 mass% of the resin composition. By thus reducing the blending amount of the aliphatic polyamide resin, the flame retardancy of the obtained molded article tends to be further improved. The content of the aliphatic polyamide resin in the resin composition of the present embodiment is preferably less than 0.5 mass%, more preferably less than 0.1 mass%, and even more preferably less than 0.05 mass%. There is no particular lower limit, and it may be 0 mass% or more, or may be 0.0001 mass% or more. Examples of the aliphatic polyamide resin include polyamide 6, polyamide 11, polyamide 12, polyamide 46, polyamide 66, polyamide 610, polyamide 612, polyamide 6 / 66, polybis(4-aminocyclohexyl)methane dodecamide, polybis(3-methyl-4-aminocyclohexyl)methane dodecamide, polyisophorone adipamide, and the like.

[0027] <(B) Reinforcing fiber> In the resin composition of the present embodiment, in the resin composition in which the total of the above (A) to (E) is 100.0 mass%, 35.0 to 60.0 mass% of reinforcing fiber is contained. By containing the reinforcing fiber, a molded article excellent in mechanical strength can be obtained. The reinforcing fiber may be an organic reinforcing fiber or an inorganic reinforcing fiber, and an inorganic reinforcing fiber is preferable. The reinforcing fiber is preferably a plant fiber, carbon fiber, glass fiber, alumina fiber, boron fiber, ceramic fiber, aramid fiber, etc., more preferably selected from carbon fiber and glass fiber, and even more preferably glass fiber.

[0028] As the glass fiber, fibers obtained by melt spinning generally supplied glasses such as E glass, C glass, A glass, S glass, D glass, R glass, and alkali-resistant glass are used. However, any fiber that can be made into glass fiber can be used and is not particularly limited. In the present invention, it is preferably included E glass.

[0029] The glass fiber is preferably surface-treated with a surface treatment agent such as a silane coupling agent such as γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane. The adhesion amount of the surface treatment agent is preferably 0.01 to 1.0% by mass of the glass fiber. Further, if necessary, lubricants such as fatty acid amide compounds and silicone oils, antistatic agents such as quaternary ammonium salts, resins having film-forming ability such as epoxy resins and urethane resins, and mixtures of resins having film-forming ability with heat stabilizers, flame retardants, etc. Those surface-treated can also be used.

[0030] The glass fiber used in the resin composition of the present embodiment is available as a commercial product. Examples of commercial products include T275H, T286H, T756H, T289, T289DE, T289H, T296GH manufactured by Nippon Electric Glass (NEG) Co., Ltd.; DEFT2A manufactured by Owens Corning Co., Ltd., HP3540 manufactured by PPG Co., Ltd.; CSG3PA-810S, CSG3PA-820 manufactured by Nitto Boseki Co., Ltd.; EFH50-31 (all are trade names) manufactured by Central Glass Fiber Co., Ltd., etc.

[0031] The cross-section of the reinforcing fiber may be either circular or non-circular (elliptical, oblong, rectangular, a shape with semi-circles joined to both short sides of a rectangle, comma-shaped, etc.), and is preferably circular. When using a reinforcing fiber having a circular cross-section as the reinforcing fiber in the present invention, in particular, the effects of improving flame retardancy and mechanical strength are remarkable. The circular shape here means, in addition to a perfect circle in the geometric sense, those that are usually referred to as circular in the technical field of the present invention. Examples of the reinforcing fiber having a non-circular cross-section include the reinforcing fibers having a flat shape described in paragraphs 0048 to 0052 of JP-A-2012-214819, and the contents thereof are incorporated herein.

[0032] The reinforcing fiber in the resin composition of the present embodiment preferably has a number average fiber length of 100 μm or more, more preferably 150 μm or more, and even more preferably 200 μm or more. As the upper limit value, it is preferably 10 mm or less, more preferably 8 mm or less, and even more preferably 5 mm or less.

[0033] The reinforcing fiber used in the resin composition of the present embodiment preferably has a number average fiber diameter of 1 μm or more, more preferably 2 μm or more, and even more preferably 5 μm or more. As the upper limit value, it is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less.

[0034] In the resin composition of this embodiment, the proportion of the reinforcing fiber (preferably glass fiber) has a lower limit of 35.0% by mass or more, preferably 38.0% by mass or more, more preferably 40.0% by mass or more, still more preferably 42.0% by mass or more, and may even be 45.0% by mass or more. The upper limit of the content is 60.0% by mass or less, usually 59.0% by mass or less, preferably 55.0% by mass or less, and more preferably 52.0% by mass or less. By setting the lower limit as described above, the flexural strength can be improved and the flame retardancy can also be improved. On the other hand, by setting the amount of the reinforcing fiber to be within the upper limit as described above, the moldability tends to be further improved. The resin composition of this embodiment may contain only one kind of reinforcing fiber or two or more kinds of reinforcing fibers. When two or more kinds are contained, the total amount is preferably within the above range.

[0035] <(C) Phosphorus-based flame retardant> The resin composition of this embodiment contains 1.0% by mass or more and less than 10.0% by mass of a phosphorus-based flame retardant in the resin composition in which the total of the above (A) to (E) is 100.0% by mass. By containing a phosphorus-based flame retardant, a molded product excellent in flame retardancy can be obtained. Examples of the (C) phosphorus-based flame retardant include phosphorus, phosphates, phosphate esters, phosphazenes, reaction products of melamine and phosphoric acid, etc. The reaction product of melamine and phosphoric acid can refer to the description in paragraph 0028 of JP-A-2018-065974, and this content is incorporated herein. In this embodiment, it is preferable that the (C) phosphorus-based flame retardant contains at least one of phosphinates and diphosphinates.

[0036] In this embodiment, it is further preferable that the (C) phosphorus-based flame retardant contains at least one of the compound represented by the following formula (I) and the compound represented by formula (II).

Chemical formula

[0037] In formula (I), R 1 and R 2 Each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, and is preferably a methyl group, an ethyl group, a propyl group, or a phenyl group. M represents a calcium ion, an aluminum ion, a magnesium ion, or a zinc ion. m is a natural number representing the valence of M, and is preferably 2 or 3.

[0038] In formula (II), R 4 and R 5 Each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, and is preferably a methyl group, an ethyl group, a propyl group, or a phenyl group. R 3represents a linear or branched alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, an alkylarylene group having 7 to 10 carbon atoms, or an arylalkylene group having 7 to 10 carbon atoms, and is preferably a methylene group, an ethylene group, a propylene group, or a phenylene group. M represents a calcium ion, an aluminum ion, a magnesium ion, or a zinc ion. n represents a natural number representing the valence of M. n, a, and b are natural numbers satisfying the relational expression 2×b = n×a. n is preferably 2 or 3. b is preferably 1, 2, or 3, and more preferably 1 or 3. a is preferably 1 or 2.

[0039] Specific examples of the phosphinate or diphosphinate include those produced in an aqueous medium using phosphinic acid and a metal carbonate, a metal hydroxide, or a metal oxide. The phosphinate or diphosphinate is basically a monomeric compound, but depending on the reaction conditions and the environment, it may become a polymeric phosphinate with a degree of condensation of 1 to 3.

[0040] Examples of the phosphinic acid or diphosphinic acid include dimethylphosphinic acid, ethylmethylphosphinic acid, diethylphosphinic acid, methyl-n-propylphosphinic acid, methanedi(methylphosphinic acid), benzene-1,4-di(methylphosphinic acid), methylphenylphosphinic acid, and diphenylphosphinic acid.

[0041] Examples of the phosphinate include calcium dimethylphosphinate, magnesium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, magnesium ethylmethylphosphinate, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, magnesium diethylphosphinate, aluminum diethylphosphinate, zinc diethylphosphinate, calcium methyl-n-propylphosphinate, magnesium methyl-n-propylphosphinate, aluminum methyl-n-propylphosphinate, zinc methyl-n-propylphosphinate, calcium methylphenylphosphinate, magnesium methylphenylphosphinate, aluminum methylphenylphosphinate, zinc methylphenylphosphinate, calcium diphenylphosphinate, magnesium diphenylphosphinate, aluminum diphenylphosphinate, zinc diphenylphosphinate and the like.

[0042] Examples of the diphosphinate include calcium methanedi(methylphosphinate), magnesium methanedi(methylphosphinate), aluminum methanedi(methylphosphinate), zinc methanedi(methylphosphinate), calcium benzene-1,4-di(methylphosphinate), magnesium benzene-1,4-di(methylphosphinate), aluminum benzene-1,4-di(methylphosphinate), zinc benzene-1,4-di(methylphosphinate) and the like.

[0043] Among these phosphinates or diphosphinates, aluminum ethylmethylphosphinate, aluminum diethylphosphinate, and zinc diethylphosphinate are particularly preferred from the viewpoints of flame retardancy and electrical properties. Specific products include EXOLIT OP 1230 (aluminum phosphinate) and OP 1400 (both are trade names) manufactured by Clariant.

[0044] In the resin composition of this embodiment, the content of the phosphorus-based flame retardant (preferably at least one of phosphinates and diphosphinates) is 1.0% by mass or more, preferably 2.0% by mass or more, more preferably 2.5% by mass or more, and even more preferably 3.0% by mass or more in the resin composition. The upper limit is less than 10.0% by mass, preferably 9.0% by mass or less. If the amount of the flame retardant is too large, the resulting molded product has excellent performance, but is likely to cause gas generation and mold contamination during molding. The resin composition of this embodiment may contain only one kind of flame retardant or two or more kinds of flame retardants. When two or more kinds are contained, it is preferable that the total amount is within the above range.

[0045] <(D) Hydrated metal salt> In the resin composition in which the total of the above (A) to (E) is 100.0% by mass, the resin composition of this embodiment contains 0.1 to 10.0% by mass of a hydrated metal salt having a dehydration temperature 100°C or higher than the melting point according to the differential scanning calorimetry of the (A) semi-aromatic polyamide resin. By including the hydrated metal salt, it becomes possible to maintain high flame retardancy while maintaining the high mechanical strength that the molded product containing the aromatic polyamide resin and the reinforcing fiber inherently has.

[0046] The hydrated metal salt is a compound that contains a metal and undergoes a dehydration reaction by heat. Specifically, metal salts having a hydroxyl group, metal salt hydrates, etc. are exemplified. Since the dehydration temperature of such a hydrated metal salt is 100°C or higher than the melting point of the semi-aromatic polyamide resin, it does not affect the molding or processing of the resin composition, and can appropriately cause a dehydration reaction during combustion. Therefore, while not reducing the mechanical strength of the molded product due to water content, when the molded product burns, water can be appropriately released. Here, the dehydration temperature refers to the thermal decomposition temperature of the hydrated metal salt, specifically, the temperature at which weight loss starts.

[0047] The hydrated metal salt used in this embodiment has a dehydration temperature that is 100 °C or higher, preferably 120 °C or higher, and more preferably 150 °C or higher than the melting point of the (A) semi-aromatic polyamide resin. As the upper limit value of the dehydration temperature, it is practical that it is the melting point of the (A) semi-aromatic polyamide resin + 350 °C or lower. In addition, when using two or more types of (A) semi-aromatic polyamide resins, the "melting point of the (A) semi-aromatic polyamide resin" means the melting point of the (A) semi-aromatic polyamide resin having the highest melting point among the (A) semi-aromatic polyamide resins contained in the resin composition. Also, the dehydration temperature of the hydrated metal salt used in this embodiment is 300 °C or higher, and it is practical that it is 700 °C or lower.

[0048] The hydrated metal salt used in this embodiment is preferably a neutral metal salt. Specifically, when dissolved in water, the pH is preferably 5 to 9, and more preferably 6 to 8. By using such a neutral metal salt, a molded product that is less likely to deteriorate in quality can be obtained.

[0049] The hydrated metal salt used in this embodiment preferably contains boehmite. Boehmite is a neutral metal salt and can make it less likely to cause quality deterioration of the molded product.

[0050] The content of the hydrated metal salt (preferably boehmite) in the resin composition of this embodiment is 0.1% by mass or more in the resin composition, preferably 0.5% by mass or more, more preferably 1.0% by mass or more, further preferably 1.5% by mass or more, and still more preferably 3.0% by mass or more. By setting it to be the above lower limit value or more, the flame retardancy of the obtained molded product is further improved. As the upper limit, it is 10.0% by mass or less, preferably 8.0% by mass or less, and more preferably 6.0% by mass or less. By setting it to be the above upper limit value or less, the mechanical strength of the molded product tends to be further improved. The resin composition of this embodiment may contain only one type of a predetermined hydrous metal salt, or may contain two or more types. When two or more types are contained, it is preferable that the total amount falls within the above range.

[0051] <(E) Other Additives> The resin composition of this embodiment contains 0 to 25.0% by mass of at least one additive other than the above in a resin composition in which the total of the above (A) to (E) is 100.0% by mass. That is, the resin composition of this embodiment may be composed only of the components of the above (A) to (D), or may contain (E) other additives at a ratio of 25.0% by mass or less in addition to the above.

[0052] Examples of other additives include nucleating agents, mold release agents, light stabilizers, heat stabilizers, alkalis, elastomers, titanium oxide, antioxidants, hydrolysis resistance improvers, matting agents, ultraviolet absorbers, plasticizers, dispersants, antistatic agents, anti-coloring agents, anti-gelling agents, coloring agents, and the like. Details of these can be referred to the descriptions in paragraphs 0130 to 0155 of Japanese Patent No. 4894982, and the contents thereof are incorporated herein. (E) The additives preferably total 20.0% by mass or less of the resin composition, more preferably 15.0% by mass or less, still more preferably 10.0% by mass or less, and even more preferably 5.0% by mass or less. The lower limit of the content of the (E) additives is preferably 0.5% by mass or more. (E) Only one type of additive may be used, or two or more types may be used in combination. The total of components (A) to (E) of the resin composition of this embodiment is 100% by mass.

[0053] <<Nucleating Agent>> As described above, the resin composition of this embodiment may contain a nucleating agent. By containing a nucleating agent, crystallization can be promoted, and dimensional stability and product appearance can be improved. The nucleating agent is preferably talc. As the talc, those surface-treated with at least one compound selected from polyorganohydrogensiloxanes and organopolysiloxanes may be used. In this case, the adhesion amount of the siloxane compound in the talc is preferably 0.1 to 5% by mass of the talc.

[0054] When blended, the content of the nucleating agent in the resin composition of this embodiment is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the polyamide resin.

[0055] <<Release agent>> As described above, the resin composition of this embodiment may contain a release agent. The release agent is mainly used to improve the productivity during the molding of the resin composition. Examples of the release agent include aliphatic carboxylic acid amide-based, aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15000, polysiloxane-based silicone oils, and the like.

[0056] Details of the release agent can refer to the descriptions in paragraphs 0037 to 0042 of JP-A-2016-196563 and paragraphs 0048 to 0058 of JP-A-2016-078318, and these contents are incorporated herein.

[0057] When the release agent is included, the lower limit is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and the upper limit is preferably 2.0% by mass or less, more preferably 1.5% by mass or less, based on the resin composition. By setting the content within such a range, the mold release property can be improved and mold contamination can be effectively suppressed when performing mold forming such as injection molding. The release agent may be used alone or in combination of two or more. When two or more are used, the total amount preferably falls within the above range.

[0058] <Properties of the resin composition> The resin composition of this embodiment preferably has a flexural strength of 290 MPa or more, more preferably 301 MPa or more, and even more preferably 316 MPa or more at a temperature of 23°C when molded into an ISO tensile test piece (4 mm thick) in accordance with ISO 178. The upper limit value of the flexural strength is not particularly defined, but 500 MPa or less is practical.

[0059] The resin composition of this embodiment preferably has a flexural modulus of elasticity of 17.0 GPa or more, more preferably 18.0 GPa or more, and even more preferably 19.0 GPa or more at a temperature of 23°C when molded into an ISO tensile test piece (4 mm thick) in accordance with ISO 178. The upper limit value of the flexural modulus of elasticity is not particularly defined, but 30 GPa or less is practical.

[0060] The resin composition of this embodiment, when molded into an ISO tensile test piece (4 mm thick) in accordance with ISO 179-1 and 2, has a notched Charpy impact strength of 6 kJ / m 2 or more, more preferably 7 kJ / m 2 or more, in an environment of a temperature of 23°C and a humidity of 50%. The upper limit value is not particularly defined, but 20 kJ / m 2 or less is practical.

[0061] The resin composition of this embodiment is preferably evaluated as V-0 when formed into a thickness of 0.8 mm and subjected to the combustion test of the UL94 test. Further, the resin composition of this embodiment is preferably evaluated as V-1 or higher, more preferably evaluated as V-0, when formed into a thickness of 0.5 mm and subjected to the combustion test of the UL94 test. The flexural strength, bending strength, and combustion test of the UL94 test are measured by the methods described in the examples below.

[0062] <Manufacturing method of resin composition> In this embodiment, the manufacturing method of the resin composition is not particularly defined, and the manufacturing methods of known thermoplastic resin compositions can be widely adopted. Specifically, after premixing each component using various mixers such as a tumbler or a Henschel mixer, the resin composition can be manufactured by melt-kneading with a Banbury mixer, a roll, a Brabender, a single-screw extruder, a twin-screw extruder, a kneader, etc.

[0063] Also, for example, without premixing each component, or premixing only some of the components, and feeding them to an extruder using a feeder for melt-kneading, the resin composition can also be manufactured. Furthermore, for example, a composition obtained by premixing some components and feeding them to an extruder for melt-kneading is used as a masterbatch, and this masterbatch is mixed with the remaining components again and melt-kneaded to produce pellets.

[0064] <Molded product> The molded product of this embodiment is formed from the resin composition of this embodiment. The molded product of this embodiment may be a thin-walled molded product. The thin-walled molded product refers to a molded product having a thin-walled portion. For example, a molded product having a thin-walled portion with a thickness of less than 1 mm is exemplified. The lower limit value of the thin-walled portion is, for example, 0.1 mm or more. The manufacturing method of the molded product of this embodiment is not particularly defined. As an example, an injection molded product molded by injection molding is exemplified. For example, after melt-kneading each component, the molded product of this embodiment may be directly molded by various molding methods, or after melt-kneading each component and pelletizing it, it may be melted again and molded by various molding methods.

[0065] The method for molding the molded product is not particularly limited, and a conventionally known molding method can be adopted. For example, injection molding method, injection compression molding method, extrusion molding method, profile extrusion method, transfer molding method, blow molding method, gas-assisted blow molding method, blow molding method, extrusion blow molding, IMC (in-mold coating molding) molding method, rotational molding method, multilayer molding method, two-color molding method, insert molding method, sandwich molding method, foam molding method, pressure molding method, etc. can be mentioned.

[0066] The shape of the molded product of this embodiment is not particularly limited and can be appropriately selected according to the use and purpose of the molded product. For example, plate-like, plate-shaped, rod-shaped, sheet-shaped, film-shaped, cylindrical, annular, circular, elliptical, gear-shaped, polygonal-shaped, irregular-shaped products, hollow products, frame-shaped, box-shaped, panel-shaped ones, etc. can be mentioned.

[0067] There is no particular limitation on the field of use of the molded product of this embodiment, and it is widely used in transportation machine parts such as automobiles, general machine parts, precision machine parts, electronic and electrical equipment parts, OA equipment parts, building materials and housing-related parts, medical devices, leisure sports goods, toys, medical products, daily necessities such as food packaging films, defense and aerospace products, etc.

Examples

[0068] The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. When the measuring instruments used in the examples are difficult to obtain due to being obsolete or the like, measurements can be made using other devices having equivalent performance.

[0069] Raw materials <Polyamide resin (PA)> MP6: It was synthesized according to the following synthesis example. <<Synthesis Example of MP6>> Into a reaction vessel equipped with a stirrer, a partial condenser, a total condenser, a thermometer, a dropping funnel, a nitrogen inlet tube, and a strand die, 7220 g (49.4 mol) of adipic acid (manufactured by Invista) and 11.66 g of sodium acetate / sodium hypophosphite monohydrate (molar ratio = 1 / 1.5) were charged. After sufficient nitrogen substitution, the system was heated to melt at 170 °C while stirring under a small amount of nitrogen flow. 6647 g of a mixed xylylenediamine with a molar ratio of meta-xylylenediamine to para-xylylenediamine of 70 / 30 (34.16 mol of meta-xylylenediamine, 14.64 mol of para-xylylenediamine, manufactured by Mitsubishi Gas Chemical Company) was added dropwise to the melt in the reaction vessel with stirring, and the internal temperature was continuously raised to 260 °C over 2.5 hours while discharging the generated condensed water out of the system. After the completion of the dropping, the internal temperature was raised. When it reached 270 °C, the inside of the reaction vessel was depressurized, and the internal temperature was further raised to continue the melt polycondensation reaction at 280 °C for 20 minutes. Then, the system was pressurized with nitrogen, and the obtained polymer was taken out from the strand die and pelletized to obtain a polyamide resin. When the melting point was measured according to the method described later, it was 256 °C.

[0070] PA66: Polyamide 66, manufactured by Solvay, Zytel 26AE1K, melting point 264 °C

[0071] <Glass Fiber (GF)> T-275H: Circular cross-section glass fiber, manufactured by Nippon Electric Glass Co., Ltd., E-glass, chopped strand, number average fiber diameter 10 μm <Talc> Micron White MW5000S: Manufactured by Hayashi Kasei Co., Ltd., average particle size 5 μm <Release Agent> Light Amide WH-255: Manufactured by Kyoeisha Chemical Co., Ltd., higher fatty acid amide

[0072] <Flame Retardant> Metal phosphinate: Manufactured by Clariant Chemicals, Exolit OP1230 Phosphazene: manufactured by Otsuka Chemical Co., Ltd., SPS-100 <Metal salt> Boehmite: manufactured by Kawaai Lime Industry Co., Ltd., Ceralure BMT-3LV, AlOOH, dehydration temperature 450 °C Zinc borate: manufactured by BORAX, Firebreak ZB, 2ZnO·3B2O3·3.5H2O, dehydration temperature 290 °C Aluminum hydroxide: manufactured by FUJIFILM Wako Pure Chemical Corporation, Al(OH)3, dehydration temperature 200 °C

[0073] <Method for measuring melting point> For measuring the melting point of the polyamide resin, a differential scanning calorimeter (DSC) was used. The sample amount was about 10 mg. Nitrogen was flowed as the atmosphere gas at 30 mL / min, and the temperature was raised at a rate of 10 °C / min. The melting point was determined from the peak top temperature of the endothermic peak observed when heating from room temperature to a temperature above the expected melting point until melting. As the differential scanning calorimeter (DSC), DSC7200 manufactured by Hitachi High-Tech Science Corporation was used.

[0074] Examples 1 to 3, Comparative Examples 1 to 4, Reference Example 1 <Compound> As shown in Table 1, each was weighed, and the components other than the glass fiber were blended in a tumbler and charged from the bottom of a twin-screw extruder (manufactured by Shibaura Machine Co., Ltd., TEM26SS) and melted. Then, the glass fiber was side-fed to produce polyamide resin pellets. The temperature setting of the twin-screw extruder was 280 °C.

[0075] <Flexural strength and flexural modulus> After drying the polyamide resin pellets obtained by the above manufacturing method at 120 °C for 3 hours, ISO tensile test pieces (4 mm thick) were injection molded using an injection molding machine (manufactured by Nissei Plastic Industrial Co., Ltd., "NEX140III") under the conditions of a cylinder temperature of 280 °C, a mold temperature of 130 °C, and a molding cycle of 50 seconds. In accordance with ISO 178, using the above ISO tensile test pieces (4 mm thick), the flexural strength (unit: MPa) and flexural modulus (unit: GPa) were measured in an environment of a temperature of 23 °C and a humidity of 50%. The results are shown in Table 1 below.

[0076] <Notched Charpy impact strength> In accordance with ISO179-1 and 2, using the above ISO tensile test specimen (4 mm thick), the notched Charpy impact strength (unit: kJ / m 2 ) was measured at a temperature of 23°C and a humidity of 50% using a 1 J hammer. The results are shown in Table 1 below.

[0077] <Heat deflection temperature under load> In accordance with ISO75-1 and 2, using the above ISO tensile test specimen (4 mm thick), the heat deflection temperature under load (unit: °C) was measured under a flexural stress of 1.80 MPa.

[0078] <Flammability (UL94 test)> After drying the polyamide resin pellets obtained by the above manufacturing method at 120°C for 4 hours, injection molding was performed using an injection molding machine (manufactured by Japan Steel Works, Ltd., "J50-EP") to form UL test combustion pieces with a length of 125 mm, a width of 13 mm, and thicknesses of 0.5 mm and 0.8 mm. The cylinder temperature and mold temperature were set at 280°C and 130°C, respectively. The UL test combustion pieces obtained by the above method were conditioned in a constant temperature chamber at a temperature of 23°C and a humidity of 50% for 48 hours and then subjected to the UL94 test. The results are shown in Table 1 below.

[0079] <Gas ejected from nozzle> When forming the above UL test combustion pieces, the amount of gas ejected from the nozzle during resin change was visually evaluated. The results are shown in Table 1 below. A: The state where thin gas gently rises upward from the resin discharged from the nozzle B: The gas is denser than A above, and / or the gas is ejected vigorously together with the resin discharged from the nozzle more than A

[0080]

Table 1

[0081] The unit of each component in Table 1 above is mass%. As is clear from the above results, the resin composition of the present invention was able to maintain the high mechanical strength inherent in molded articles formed from polyamide resins and also enhance the flame retardancy while maintaining the high mechanical strength (Examples 1 to 3). On the other hand, when the hydrous metal salt was not included (Comparative Example 1), or when a hydrous metal salt other than the predetermined hydrous metal salt was included (Comparative Examples 2 and 3), the flame retardancy was poor. Further, when an aliphatic polyamide resin was used as the polyamide resin, the flame retardancy was poor (Comparative Example 4).

Claims

1. (A) 28.0 to 50.0% by mass of a semi-aromatic polyamide resin, (B) 35.0 to 60.0% by mass of a reinforcing fiber, (C) 1.0% by mass or more and less than 10.0% by mass of a phosphorus-based flame retardant, (D) 0.1 to 10.0% by mass of a hydrated metal salt having a dehydration temperature 100°C or higher than the melting point according to differential scanning calorimetry of the (A) semi-aromatic polyamide resin, (E) Consisting of 0 to 25.0% by mass of at least one additive other than the above, A resin composition in which the total of components (A) to (E) is 100.0% by mass, The content of the aliphatic polyamide resin is less than 1.0% by mass of the resin composition, The resin composition, wherein the melting point of the (A) semi-aromatic polyamide resin is 200°C or higher and 300°C or lower.

2. (A) 28.0 to 50.0% by mass of a semi-aromatic polyamide resin, (B) 35.0 to 60.0% by mass of a reinforcing fiber, (C) 1.0% by mass or more and less than 10.0% by mass of a phosphorus-based flame retardant, (D) 0.1 to 10.0% by mass of a hydrated metal salt having a dehydration temperature 100°C or higher than the melting point according to differential scanning calorimetry of the (A) semi-aromatic polyamide resin, (E) Consisting of 0 to 25.0% by mass of at least one additive other than the above, A resin composition in which the total of components (A) to (E) is 100.0% by mass, The content of the aliphatic polyamide resin is less than 1.0% by mass of the resin composition, The resin composition, wherein the (A) semi-aromatic polyamide resin contains a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, and 70 mol% or more of the structural unit derived from diamine is derived from xylylenediamine.

3. The resin composition according to claim 1 or 2, wherein the (C) phosphorus-based flame retardant contains at least one of phosphinate and diphosphinate.

4. The resin composition according to any one of claims 1 to 3, wherein the (A) semi-aromatic polyamide resin contains a structural unit having a linear aliphatic chain with 4 to 7 carbon atoms.

5. The resin composition according to any one of claims 1 to 4, wherein the (D) hydrated metal salt contains boehmite.

6. The resin composition according to any one of claims 1 to 5, wherein the (B) reinforcing fiber contains glass fiber.

7. The resin composition according to any one of claims 1 to 6, wherein the (C) phosphorus-based flame retardant contains at least one of a compound represented by the following formula (I) and a compound represented by the following formula (II). 【Chemical 1】 (In formula (I), R １ and R ２ each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. M represents a calcium ion, an aluminum ion, a magnesium ion, or a zinc ion. m is a natural number representing the valence of M.) [Chemical Formula 2] (In formula (II), R ４ and R ５ each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. R ３ represents a linear or branched alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, an alkylarylene group having 7 to 10 carbon atoms, or an arylalkylene group having 7 to 10 carbon atoms. M represents a calcium ion, an aluminum ion, a magnesium ion, or a zinc ion. n represents a natural number representing the valence of M. n, a, and b are natural numbers satisfying the relational expression 2 × b = n × a.)

8. The resin composition according to any one of claims 1 to 7, wherein the content of the (C) phosphorus-based flame retardant is 1.0 to 9.0% by mass.

9. A molded article formed from the resin composition according to any one of claims 1 to 8.

10. The molded article according to claim 9, wherein the molded article has a thin portion with a thickness of less than 1 mm.

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