TW202246471A - Flame-retardant polyamide resin composition and molded article comprising same - Google Patents

Abstract

To provide a flame-retardant polyamide resin composition that is suitable for a molded component having a thin-wall portion such as a hinge portion, that has excellent flame retardancy, and from which it is possible to mold a molded article having excellent bending durability at the hinge portion.

Description

Flame-retardant polyamide resin composition and molded articles made of it

The present invention relates to a non-halogen flame retardant polyamide resin composition. In detail, it relates to a non-halogen flame-retardant polyamide resin composition which has high flame retardancy and good toughness, and is especially suitable for molded products with hinges.

Polyamide resins are used in various fields such as electrical and electronic parts and automobile parts, taking advantage of their excellent mechanical properties, electrical properties, chemical resistance, and the like. In these fields, melamine cyanurate is used as a flame retardant when flame retardancy imparted by a non-reinforced non-halogen flame retardant is required (for example, Patent Documents 1 and 2). However, melamine cyanurate has the following disadvantages: poor dispersibility for polyamide resins and lowering of the mechanical properties of polyamide resins; bleeding when blended in large amounts; easy decomposition and sublimation into melamine and melamine due to thermal decomposition Polycyanuric acid; due to the influence of sublimated melamine and cyanuric acid, silver streaks will be produced on the surface of molded products during molding processing; it is easy to contaminate the surface of molds, etc.

In recent years, the level of demand for various electrical and electronic parts, automotive parts, etc. has increased. For parts with thin-walled parts such as hinges, not only the flame retardancy is required to be UL94 thickness 0.4mm and V-0 level, but also it is expected to have hinges. Among molded products of the part, the hinge part has excellent bending durability. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 58-25379 [Patent Document 2] Japanese Patent Publication No. 58-35541

[Problem to be Solved by the Invention]

The object of the present invention is to provide a flame-retardant polyamide resin composition, which is suitable for forming parts with thin-walled parts such as hinge parts, and can be formed with not only UL94 thickness of 0.4mm but also V-0 grade flame retardancy, In addition, the hinge portion is excellent in bending durability, and in particular, the hinge portion retains a molded product having excellent bending durability even in a low-temperature environment or after annealing treatment. [Means to solve the problem]

The inventors of the present invention earnestly studied to solve the above-mentioned problems, and as a result, completed the present invention.

That is, the present invention has the following configurations. [1] A flame-retardant polyamide resin composition, characterized in that: the composition ( A) and (B), and containing 0.01 to 2 parts by mass of hypophosphite metal salt (C) with respect to the total of 100 parts by mass of the aforementioned components (A) and (B), and containing a lubricant (D), a phosphorus-based antioxidant Oxidant (E), phenolic antioxidant (F), and meet the following requirements (1) to (3): (1) 10≦The terminal amino group concentration (eq/ton) of the polyamide resin (A)≦39; (2) Melt flow rate (275°C, 1kgf)≧40; (3) 236°C ≦ cooling crystallization temperature (Tc2) ≦ 242°C. [2] A method for producing a flame-retardant polyamide resin composition as claimed in claim 1, comprising melting the polyamide resin (A), melamine cyanurate (B) and hypophosphite metal salt (C) The step of kneading; relative to the total amount of polyamide resin (A), the ratio of polyamide 66 resin (A1) is 45 to 75% by mass, and the ratio of polyamide 6 resin (A2) is 10 to 40% by mass , and the amorphous polyamide resin (A3) at a ratio of 0 to 8% by mass. [3] The flame-retardant polyamide resin composition according to Claim 1 or 2, which further contains 0.01 to 1 part by mass of a lubricant (D) relative to 100 parts by mass of the above-mentioned flame-retardant polyamide resin composition , 0.01 to 1 part by mass of phosphorus antioxidant (E), and 0.01 to 1 part by mass of hindered phenolic antioxidant (F). [4] The flame-retardant polyamide resin composition according to any one of claims 1 to 3, wherein the phosphorus-based antioxidant (E) is a compound having a neopentylthritol diphosphite skeleton. [5] A flame-retardant polyamide resin composition for a hinge member, which is the flame-retardant polyamide resin composition according to any one of Claims 1-4. [6] A molded article having a hinge portion comprising the flame-retardant polyamide resin composition according to any one of claims 1 to 4. [7] The molded product having a hinge portion according to claim 5, which is any one of a ferrite core cover, a cable tie, and a wire harness protection member. [Effect of Invention]

The flame retardant polyamide resin composition of the present invention can be molded into a hinge retaining molded product which not only has UL94 thickness of 0.4mm and V-0 grade flame retardancy, but also has excellent bending durability of the hinge.

The present invention will be specifically described below. The flame-retardant polyamide resin composition of the present invention is characterized in that the component (A) is contained in a ratio of 97.5-93 parts by mass of polyamide resin (A) and 2.5-7 parts by mass of melamine cyanurate (B). and (B), and containing 0.01 to 2 parts by mass of hypophosphite metal salt (C) with respect to the total of 100 parts by mass of the aforementioned components (A) and (B), and meeting the following (1) to (3) A flame retardant polyamide resin composition that is essential. (1) 10≦The terminal amino group concentration of polyamide resin (A) (eq/ton)≦39 (2) Melt flow rate (275°C, 1kgf)≧40 (3) 236°C ≦ cooling crystallization temperature (Tc2) ≦ 242°C

The average terminal amine group concentration (eq/ton) in the requirement (1) of the present invention refers to the terminal amine group concentration (eq/ton) of each resin and their mixture when it is a mixture of multiple polyamide resins Calculated value of ratio (mean AEG). Preferably 10≦(average AEG)≦38, more preferably 10≦(average AEG)≦37, when the (average AEG) exceeds 39, it becomes difficult to promote the retardation of the crystallization rate caused by the amide exchange reaction As a result, the relaxation of resin alignment in the vicinity of the mold becomes less likely to occur, so cracking of the hinge portion becomes more likely to occur.

The melt flow rate in the requirement (2) of the present invention is the melt fluidity (MFR) measured by the ISO1133 method of the flame-retardant polyamide resin composition of the present invention, preferably more than 50, more preferably 60 or more. When the (MFR) is a melt fluidity lower than the requirement (2) of the present invention, alignment of the resin near the mold is formed, and cracking of the hinge portion tends to occur.

The cooling crystallization temperature (Tc2) in the requirement (3) of the present invention is the temperature measured by heat flux differential scanning calorimetry (heat flux DSC), preferably 238°C≦(Tc2)≦241°C, When (Tc2) exceeds 242°C, relaxation of resin alignment near the mold becomes less likely to occur, and cracks at the hinge portion tend to occur, and when it is less than 236°C, moldability tends to be poor.

Hereinafter, various raw materials used in the present invention are further described in detail. [Polyamide resin (A)] The polyamide resin (A) in the present invention is not particularly limited if it is a polymer having an amide bond (-NHCO-) in the main chain. The polyamide resin (A) is preferably crystalline, and examples thereof include polyamide 6 (PA6), polyamide 66 (PA66), polyamide 46 (PA46), polyamide 11 (PA11), polyamide Amine 12 (PA12), polyamide 610 (PA610), polyamide 612 (PA612), polym-xylyl adipamide (PAMXD6), hexamethylenediamine-terephthalic acid polymer (PA6T ), hexamethylenediamine-terephthalic acid and adipic acid polymer (PA6T/66), hexamethylenediamine-terephthalic acid and ε-caprolactam copolymer (PA6T/6) , trimethylhexamethylenediamine-terephthalic acid polymer (PATMD-T), m-xylylenediamine, adipic acid and isophthalic acid copolymer (PAMXD6/MXDI), trimethylhexamethylene Crystalline polyamides such as methyldiamine, terephthalic acid and ε-caprolactam copolymer (PATMDT/6), diamine dicyclohexylenemethane, isophthalic acid and lauryl lactam copolymer Resins, or their blends, etc., but not limited to these.

The blending amount (content) of the polyamide resin (A) is 97.5 to 94 parts by mass when the total of the polyamide resin (A) and melamine cyanurate (B) is 100 parts by mass. When the blending amount of the polyamide resin (A) is within this range, it is possible to impart to the composition the ability to suppress bleeding of the flame retardant and maintain high flame retardancy. The blending amount (content) of the polyamide resin (A) is preferably from 97 to 94.5 parts by mass, more preferably from 97 to 95 parts by mass. In the flame-retardant polyamide resin composition of the present invention, the blending amount of each component directly becomes the content.

The flame-retardant polyamide resin composition in the present invention can be produced by the steps of melting and kneading polyamide resin (A), melamine cyanurate (B) and hypophosphite metal salt (C) method to get. Preferably, the ratio of the polyamide 66 resin (A1) is 45 to 75% by mass, the ratio of the polyamide 6 resin (A2) is 10 to 40% by mass, relative to the total amount of the polyamide resin (A), and amorphous polyamide resin (A3) at a ratio of 0 to 8% by mass.

Examples of the polyamide 66 resin (A1) in the present invention include polyamide 66 resins obtained by polycondensation of adipic acid and hexamethylenediamine as raw materials. The relative viscosity of the polyamide 66 resin (A1) is a value measured in accordance with JIS K6810 at a concentration of 1% in 98% sulfuric acid at a temperature of 25°C, and is preferably 2.2-3.5. When the relative viscosity is less than 2.2, the mechanical properties tend to decrease, and when it exceeds 3.5, the melt fluidity tends to be insufficient. The relative viscosity of the polyamide 66 resin (A1) is more preferably 2.3-3.0.

The terminal amino group concentration of the polyamide 66 resin (A1) is preferably 10-50 eq/ton, more preferably 10-40 eq/ton in terms of hinge durability and heat discoloration resistance.

The amount of polyamide 66 resin (A1) to be blended is preferably 45 to 75 parts by mass, more preferably 50 to 70 parts by mass, from the viewpoint of hinge durability when the total polyamide resin is 100 parts by mass. . When the blending amount of the polyamide 66 resin (A1) exceeds 75 parts by mass, the hinge property (snap fit) decreases, and when it is less than 45 parts by mass, the moldability tends to decrease.

The polyamide 6 resin (A2) in the present invention is a polyamide 6 resin obtained by polycondensation using ε-caprolactam as a raw material. The relative viscosity of the polyamide 6 resin (A2) is a value measured in accordance with JIS K6810 at a concentration of 1% in 98% sulfuric acid at a temperature of 25°C, and is preferably 2.0-4.0. When the relative viscosity is less than 2.0, the mechanical properties tend to decrease, and when it exceeds 4.0, the flame retardancy tends to be impaired. The relative viscosity of the polyamide 6 resin (A2) is more preferably 2.2-3.0.

The terminal amino group concentration of the polyamide 6 resin (A2) is preferably 5-50 eq/ton, more preferably 10-40 eq/ton in terms of bending durability and heat discoloration resistance of the hinge.

The blending amount of the polyamide 6 resin (A2) is preferably 10 to 40 parts by mass when the entire polyamide resin is 100 parts by mass. When the blending amount of the polyamide 6 resin (A2) is less than 10 parts by mass, the hinge property (snap fit) tends to decrease, and when it exceeds 40 parts by mass, the molding processability tends to decrease. From the viewpoint of the balance between the snap-fit property and the formability, the compounding amount of the polyamide 6 resin (A2) is more preferably 20 to 40 parts by mass.

Amorphous polyamide resins (A3) that do not have a crystalline melting peak in the thermogram during DSC measurement can be exemplified by polymers or copolymers obtained by polycondensation as follows or blended Mixtures, etc.: from 4,4'-diamine-3,3'-dimethyldicyclohexylmethane (CA), 4,4'-diaminedicyclohexylmethane (PACM), m-xylylenediamine ( MXD), trimethylhexamethylenediamine (TMD), isophoronediamine (IA), 4,4'-diaminedicyclohexylpropane (PACP), hexamethylenediamine and other diamines, Polycondensed with dicarboxylic acids such as terephthalic acid, isophthalic acid, adipic acid, sebacic acid, and dodecanedicarboxylic acid, and lactams such as caprolactam and lauryl lactam polymers or copolymers or blends, etc.

Among them, a polyamide resin having an aromatic component is preferable in terms of lowering Tc2 and easily suppressing cracking of the hinge portion. For polyamide resins containing aromatic components, polyamide 6T/6I using terephthalic acid, isophthalic acid, and adipic acid as raw materials is preferred; terephthalic acid, adipic acid , and polyamide 6T/66 using hexamethylenediamine as a raw material; in terms of formability, polyamide 6T/6I is particularly preferred.

[melamine cyanurate (B)] As for the melamine cyanurate (B) in this invention, molar reaction products, such as cyanuric acid and melamine, are mentioned ideally. In addition, some amino groups or hydroxyl groups in melamine cyanurate may be substituted with other substituents. Melamine cyanurate can be obtained by, for example, mixing an aqueous solution of cyanuric acid and an aqueous solution of melamine, reacting them with stirring at 90 to 100° C., and filtering the resulting precipitate. The obtained solid can also be used as it is, but it is preferably crushed and used if necessary. The particle size is not particularly limited, but the average particle size is preferably from 0.5 to 20 μm, more preferably from 1 to 15 μm, from the viewpoint of flame retardancy and toughness.

The compounding quantity (content) of melamine cyanurate (B) is 2.5-7 mass parts when the total of polyamide resin (A) and melamine cyanurate (B) is 100 mass parts. From the viewpoint of flame retardancy, it is 2.5 parts by mass or more, and from the viewpoint of toughness, it is 7 parts by mass or less. More preferably, it is 2.5-6 mass parts, More preferably, it is 3-5 mass parts. In the present invention, toughness is a property related to snap fit.

[Metal Hypophosphite (C)] As far as the metal hypophosphite (C) in the present invention is concerned, it is hypophosphorous acid and 1, 2, 3, 4, 5, 6, 7, 8, 11 of the periodic table of elements , 12, 13 group elements and metal salts such as tin and lead may be used alone or in combination of two or more. Among them, sodium hypophosphite (NaH ₂ PO ₂ ) and calcium hypophosphite (Ca(H ₂ PO ₂ ) ₂ ). The hypophosphite metal salt may also be a hydrate, and examples thereof include sodium hypophosphite monohydrate (NaH ₂ PO ₂ ･H ₂ O) and the like.

The compounding quantity of hypophosphite metal salt (C) is 0.001-2 mass parts with respect to the total 100 mass parts of polyamide resin (A) and melamine cyanurate (B), Preferably it is 0.05-1.5 mass parts parts, more preferably 0.1 to 1.0 parts by mass. When the hypophosphite metal salt exists in a specific range, it can promote the amido exchange reaction between the polyamide resins, which is better for stabilizing the resin properties.

The resin composition of the present invention contains lubricant (D), phosphorus antioxidant (E), hindered phenolic antioxidant (F), etc. in order to improve formability, discoloration resistance, thermal stability, etc. better.

[Lubricant (D)] As the lubricant (D) in the present invention, esters or metal salts of long-chain fatty acids, amide compounds such as ethylidenebisterephthalamide and methylenebisstearamide, fatty acid Hydrocarbon-based, polyethylene-based waxes, polysiloxane-based polysiloxane oils, etc. These lubricants can also be used alone or as a mixture. The amount of lubricant to be added is to choose the optimum amount considering the formability and flame retardancy, but in terms of the balance between formability and flame retardancy, fatty acid metal salt-based or fatty acid ester-based lubricants are preferred .

Examples of metal salts of fatty acids include metal salts of fatty acids having 12 to 40 carbon atoms such as stearic acid, palmitic acid, behenic acid, erucic acid, oleic acid, lauric acid, and montanoic acid. Among them, metal salts of aliphatic carboxylic acids with 18 to 30 carbon atoms are preferred, and alkali metal salts of stearic acid, behenic acid, tetraceric acid, montanic acid, etc. or Alkaline earth metal salts are more preferred. Examples of alkali metal salts or alkaline earth metal salts include lithium salts, sodium salts, magnesium salts, and calcium salts.

Examples of fatty acid ester compounds include: mixtures mainly composed of myricyl palmitate, stearyl stearate, behenyl behenate, behenyl palmitate, Stearyl Ester, Glyceryl Monopalmitate, Glyceryl Monostearate, Glyceryl Distearate, Glyceryl Tristearate, Neopentylthritol Monopalmitate, Neopentylthritol Monostearate Ester, Neopentylitol Distearate, Neopentylitol Tristearate, Neopentylitol Tetrastearate, etc.

The compounding quantity (content) of a lubricant (D) is 0.01-1 mass part with respect to 100 mass parts of polyamide resin compositions. When it is less than 0.01 part by mass, mold release property may fall, and when it exceeds 1 part by mass, there may be a possibility that flame retardancy may fall. The blending amount of the lubricant (D) is preferably from 0.1 to 0.9 parts by mass.

[Phosphorus antioxidant (E)] The phosphorus-based antioxidant (E) in the present invention may be an inorganic compound or an organic compound, and is not particularly limited. In terms of ideal phosphorus compounds, inorganic phosphates such as monosodium phosphate, disodium phosphate, trisodium phosphate, sodium phosphite, calcium phosphite, magnesium phosphite, manganese phosphite can be enumerated; triphenyl phosphite, tri( Octadecyl)phosphite, Tridecylphosphite, Triisodecylphosphite, Trinonylphenylphosphite, Diphenylisodecylphosphite, Diphenylalkylphosphite ester, phenyl dialkyl phosphite, ginseng (nonylphenyl) phosphite, trilauryl phosphite, distearyl neopentylthritol diphosphite, ginseng (2,4-di- Tertiary butylphenyl) phosphite, diisodecyl neopentylthritol diphosphite, bis(2,4-di-tertiary butylphenyl) neopentylthritol diphosphite, bis( 2,6-di-tertiary butyl-4-methylphenyl) neopentylthritol diphosphite, diisodecyloxyneopentylthritol diphosphite, bis(2,4-di- Tertiary butyl-6-methylphenyl) neopentylthritol diphosphite, bis(2,4,6-ginseng(tertiary butylphenyl)) neopentylthritol diphosphite, trihard Aliphatic sorbitan triphosphite, tetra(2,4-di-tertiary butylphenyl)-4,4'-extended biphenyl diphosphonite, 6-isooctyloxy-2, 4,8,10-tetra-tertiary butyl-12H-dibenzo[d,g]-1,3,2-dioxaphosphooctacycline, 6-fluoro-2,4,8,10-tetra -Tertiary butyl-12-methyl-dibenzo[d,g]-1,3,2-dioxaphosphaoctacycline, bis(2,4-di-tertiary butyl-6-methyl Phenyl)methyl phosphite and bis(2,4-di-tertiary butyl-6-methylphenyl)ethyl phosphite, etc., and are blended in order to improve heat discoloration resistance.

Phosphite compounds are preferred as the phosphorus-based antioxidant (E). Among the phosphite compounds, a compound having a neopentylitol diphosphite skeleton is preferred. Specifically, bis(2,6-di-tert-butyl-4-methylphenyl)neopentylthritol diphosphite (“ADK STAB PEP-36”, molecular weight 633), bis(2,4 - Di-tertiary butylphenyl) neopentylthritol diphosphite ("ADK STAB PEP-24G", molecular weight 604), distearyl neopentylthritol diphosphite ("ADK STAB PEP-8 ", molecular weight 733), bis(nonylphenyl) neopentylthritol diphosphite ("ADK STAB PEP-4C", molecular weight 633), etc., which have a neopentylthritol diphosphite skeleton and a molecular weight of 600~ A value of about 800 is particularly good in that the mold release property can be further improved without reducing the flame retardancy, and the snap-fit property is also ideal.

The compounding quantity (content) of phosphorus antioxidant (E) is 0.01-1 mass part with respect to 100 mass parts of flame-retardant polyamide resin compositions. When the blending amount of the phosphorus-based antioxidant (E) is within this range, discoloration during extrusion processing can be suppressed, and secondary oxidation deterioration due to radicals derived from phosphorus can be prevented from being induced. The compounding quantity of phosphorus antioxidant (E) becomes like this. Preferably it is 0.1-0.5 mass part.

[Hindered phenolic antioxidant (F)] The hindered phenolic antioxidant (F) in the present invention includes N,N'-hexamethylene-bis-3-(3,5-di-tertiary butyl-4-hydroxyphenyl) Acrylamide, bis(3,3-bis-(4'-hydroxy-3'-tertiary butylphenyl)butanoic acid) glycol ester, 2,1'-thioethyl bis(3-(3, 5-di-tertiary butyl-4-hydroxyphenyl) propionate, 4,4'-butylene-bis(3-methyl-6-tertiary butylphenol), triethylene glycol-3- (3-tertiary butyl-4-hydroxy-5-methylphenyl) (propionate "SONGNOX 2450", molecular weight 633), etc., and a mixture of two or more of them can also be used.

The compounding amount (content) of the hindered phenolic antioxidant (F) is 0.01-1 mass part with respect to 100 mass parts of flame-retardant polyamide resin compositions. When the blending amount of the hindered phenolic antioxidant (F) is within this range, it is possible to prevent oxidation deterioration over time with an appropriate formulation amount corresponding to the coordination bond of the polyamide composition. It is preferable that the compounding quantity of a hindered phenolic antioxidant (F) is 0.1-0.5 mass part.

[other ingredients] In the flame-retardant polyamide resin composition of the present invention, in the range not detrimental to the purpose of the present invention, in addition to the above-mentioned (A), (B), (C), (D), (E), (F ), other components can be added, such as coloring agents such as pigments and dyes, or additives such as heat stabilizers, weather resistance improvers, nucleating agents, plasticizers, mold release agents, antistatic agents, and other resin polymers. In the flame-retardant polyamide resin composition of the present invention, the total of the above-mentioned components (A), (B), (C), (D), (E) and (F) preferably accounts for 80% by mass or more , more preferably 90% by mass or more, more preferably 95% by mass or more.

The ideal molded part obtained by using the flame-retardant polyamide resin composition of the present invention is a molded product having a hinge part, specifically, a joint used in the fields of electric and electronic parts, automobile parts, etc. Shaped parts with thin-walled hinge parts such as devices, bobbins, circuit breakers, electromagnetic switches, holders, plugs, sockets, switches, casings, covers, etc., more specifically, ferrite core covers , cable ties, electrical wiring protection components and other parts that require thermal discoloration and snap-fit properties.

The manufacturing method of the flame-retardant polyamide resin composition of the present invention is not particularly limited. As far as the kneading device is concerned, a general single-screw extruder, twin-screw extruder, pressurized kneader, etc. can be used, but in Particularly preferred in the present invention is a twin-screw extruder. In one embodiment, according to the aforementioned (A), (B), (C), (D), (E), (F) and the application, the pigment and the like are mixed and put into a twin-screw extruder. By uniformly kneading with a twin-screw extruder, it is possible to produce a polyamide-based resin composition excellent in toughness and flame retardancy. The kneading temperature of the twin-screw extruder is 220-300°C, and the kneading time is preferably about 2-15 minutes. [Example]

The following examples illustrate the present invention in more detail, but the present invention is not limited by these examples.

For each component, the following ones were used. Polyamide resin (A); A1-1: polyamide 66 (RV=2.8) Vydyne 21FSR (manufactured by Ascend), melting point 265°C A1-2: Polyamide 66 (RV=2.4) EPR24 (manufactured by Shanghai Shenma Plastic Technology Co., Ltd.), melting point 265°C A2-1: Polyamide 6 (RV=2.0) M2000 (manufactured by MEIDA Corporation), melting point 225°C A2-2: Polyamide 6 (RV=2.6) ZISAMIDE TP4208 (manufactured by Jisheng Company), melting point 225°C A2-3: Polyamide 6 (RV=3.6) ZISAMIDE TP6603 (manufactured by Jisheng Company), melting point 225°C A3: Polyamide 6T/6I (RV=1.9) Grivory (R) G16 (manufactured by EMS Co., Ltd.) glass transition temperature 130°C

Melamine cyanurate (B); B: MC6000 (manufactured by Nissan Chemical Co., Ltd.)

Hypophosphite metal salt (C); C: Na hypophosphite (manufactured by Taiping Chemical Industry Co., Ltd.)

lubricant (D); D1: Calcium montanate CS-8-CP (manufactured by Nitto Chemical Industry Co., Ltd.) Other release agents; D2: Fatty acid ester Licolub WE-40 (manufactured by CLARIANT JAPAN Co., Ltd.)

Phosphorous antioxidants (E); E: ADK STAB PEP-36 (manufactured by ADEKA Co., Ltd.)

Hindered phenolic antioxidant (F); F: SONGNOX2450 (manufactured by SONGWON International Japan)

[Examples 1-6, Comparative Examples 1-4] Production of evaluation samples Each raw material was weighed so that the blending ratio of the polyamide resin composition shown in Table 1 was mixed with a drum machine, and then put into a twin-screw extruder to obtain a polyamide resin composition. pellets. The setting temperature of the twin-screw extruder is set at 250° C. to 300° C., and the kneading time is set at 5 to 10 minutes. The obtained pellets were molded into various evaluation samples by an injection molding machine. The barrel temperature of the injection molding machine is set at 250°C to 280°C, and the mold temperature is set at 80°C.

Various evaluation methods are as follows. Table 1 shows the evaluation results. 1. Relative viscosity [RV] of polyamide resin (98% sulfuric acid solution method) Using an Ubbelohde viscosity tube, it was measured at 25° C. in a 98% by mass sulfuric acid solution at a polyamide resin concentration of 1 g/dl. 2. Terminal amine group concentration (AEG) of polyamide resin Dissolve the sample in deuterated benzene/HFIP-d (1/1: volume ratio) (temperature: 35°C, 1 hour), centrifuge, and 0.2M triethylamine/CDCl ₃ (CDCl ₃ containing 0.2M triethylamine) was added to the supernatant, and ¹ H-NMR measurement was performed. The samples were cut from near the center of a 100 mm x 100 mm x 3 mm resin flat plate produced by injection molding at a molding temperature of 270°C and a mold temperature of 80°C. From the obtained ¹ H-NMR analysis, the amount of amine groups was calculated from the intensity of the CH ₂ peak at the α-position of the amine group based on the weight of the polyamide resin. However, HFIP is hexafluoro-2-propanol. [NMR measurement] Device: Fourier transform nuclear magnetic resonance device (AVANCE-NEO manufactured by BRUKER) 1H resonance frequency: 600.13MHz Flip angle of detection pulse: 45° Data acquisition time: 4 seconds Delay time: 1 second 3. Cooling crystallization temperature ( Tc2) Using a differential scanning thermal analyzer (manufactured by SEIKO INSTRUMENTS Co., Ltd., EXSTAR 6000), the temperature was raised to 305°C at a heating rate of 20°C/min under a nitrogen stream and held there for 5 minutes, and then measured at a cooling rate of 10°C/min. , Obtain the exothermic peak temperature of the polyamide resin composition when the temperature is lowered, and use it as the lowered temperature crystallization temperature (Tc2). 4. Melt flow rate In accordance with the test method (A method) recorded in ISO1133, the melt flow rate (MFR: g/10min) was measured at a measurement temperature of 275°C and a load of 1000g. A polyamide resin composition with a moisture content of 0.1% by mass or less was used for the measurement. 5. Hinge durability For 20 molded products with hinges obtained by injection molding, after being placed in an environment of 5°C for 15 minutes, when the hinges are bent once in this environment, the hinges will The number of cracks and fractures was defined as "hinge crack (5°C)" and counted. Also, for molded products that have been placed in an oven at 85°C for at least 6 hours after molding, in the same way, after being placed in an environment of 5°C for 15 minutes, when the hinge is bent once in this environment, the The number of cracks and fractures in the hinge is defined as "hinge cracks (annealed at 85°C and 5°C)" and counted. 6. The flammability UL94 is measured according to the vertical burning test. The V-0 series represents the highest flame retardancy.

[Table 1] Example comparative example Blend composition (RV, AEG) 1 2 3 4 5 6 1 2 3 4 A1-1: PA66 (2.8, 43) parts by mass 67 33 67 60 72 67 A1-2: PA66 (2.4, 36) parts by mass 67 67 67 60 34 A2-1: PA6 (2.0, 25) parts by mass twenty four twenty four twenty four 36 12 26 A2-2: PA6 (2.6, 40) parts by mass twenty four 36 twenty four A2-3: PA6 (3.6, 36) parts by mass twenty four A3: PA6T6I (1.9, 15) parts by mass 5 5 5 5 5 5 5 B: Melamine cyanurate parts by mass 4 4 4 4 4 4 4 4 4 2 C: Hypophosphite Metal Salt parts by mass 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 D1: Montanic acid Ca parts by mass 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 D2: fatty acid ester parts by mass 0.8 Average AEG of PA eq/ton 31 35 34 36 36 33 39 40 36 36 Composition properties Composition Tc2 ℃ 240 240 240 240 239 240 239 238 243 241 MFR(275℃, 1kgf) g/10min 80 62 50 48 110 69 twenty three 38 40 43 Hinge crack (5°C) ◎ ◎ ◎ ◎ ◎ ◎ △ x x x Hinge cracked (85°C annealed 5°C) 〇 〇 〇 〇 〇 ◎ x x x x Flame retardant: UL94; 0.4mmt V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-2 (Note 1) Number of broken hinges (◎: 0, 〇: 1～2, △: 3～4, ×: 5≦) (Note 2) In the entire composition, 0.2 mass of phosphorus-based antioxidant (E) is blended Parts, 0.2 parts by mass of hindered phenolic antioxidant (F)

In all of Examples 1 to 6, the fracture number was 2 or less in hinge cracking (5°C) and hinge cracking (annealing at 85°C at 5°C), and good hinge durability was obtained. In terms of flame retardancy at a thickness of 0.4 mm, Examples 1 to 6 also achieved V-0 evaluation. Also, it was confirmed that Tc2 and melt flow rate of the polyamide resin composition met the requirements. In addition, when comparing Examples 1 to 6 in which hypophosphite metal salt (C) was used, and Comparative Example 4 in which only a phosphorus compound was used (only phosphorus-based antioxidants were used) instead of this, it was found that the hinge of the former was Excellent durability.

On the other hand, although Comparative Examples 1 to 4 partially satisfied the characteristics, none of them satisfied the favorable hinge durability. Comparative examples 1 and 2 are unfavorable because the melt flow rate does not meet the requirements, and the cracks of the hinge part of the resin alignment formed near the mold tend to occur. In addition, the terminal amino group concentration (eq/ton) of the polyamide resin (A) of Comparative Example 2 exceeds the upper limit of the requirements, and it becomes difficult to promote the retardation effect of the crystallization rate caused by the amide exchange reaction, which is not ideal. . In Comparative Example 3, the Tc2 of the composition did not meet the requirements, and the relaxation of the resin alignment near the mold did not easily occur, and the fracture of the hinge part was likely to occur, which is not ideal. Finally, the content ratio of the composition of Comparative Example 4 cannot meet the requirements, the relaxation of the resin alignment near the mold is less likely to occur, and the fracture of the hinge part is likely to occur, which is not ideal. In addition, the flammability is evaluated as V-2 and cannot be guaranteed. Flame retardancy, not ideal. [industrial availability]

The flame-retardant polyamide resin composition of the present invention is suitable for molded articles having a hinge portion, and the obtained molded article can be ideally used for electrical and electronic parts and automobile parts in which excellent bending durability of the hinge portion is expected. Wait.

Claims (7)

A flame-retardant polyamide resin composition, characterized in that: Component (A) and (B) containing 0.01 to 2 parts by mass of hypophosphite metal salt (C) relative to the total of 100 parts by mass of the components (A) and (B), and meeting the requirements described in the following (1) to (3) : (1) 10≦The terminal amino group concentration (eq/ton) of the polyamide resin (A)≦39; (2) Melt flow rate (275°C, 1kgf)≧40; (3) 236°C ≦ cooling crystallization temperature (Tc2) ≦ 242°C. A method for producing a flame-retardant polyamide resin composition as claimed in claim 1, comprising melting and kneading polyamide resin (A), melamine cyanurate (B) and hypophosphite metal salt (C) Step: Relative to the total amount of polyamide resin (A), polyamide 66 resin (A1) is a ratio of 45 to 75% by mass, polyamide 6 resin (A2) is a ratio of 10 to 40% by mass, and non- The ratio of the crystalline polyamide resin (A3) is 0 to 8% by mass. Such as the flame-retardant polyamide resin composition of claim 1 or 2, which further contains 0.01-1 mass part of lubricant (D), 0.01- 1 part by mass of phosphorus antioxidant (E), 0.01 to 1 part by mass of hindered phenolic antioxidant (F). The flame-retardant polyamide resin composition according to claim 1 or 2, wherein the phosphorus-based antioxidant (E) is a compound having a neopentylitol diphosphite skeleton. A flame-retardant polyamide resin composition for hinge components, which is the flame-retardant polyamide resin composition according to any one of Claims 1-4. A molded product having a hinge part, which is composed of the flame-retardant polyamide resin composition according to any one of claims 1-4. The molded product having a hinge part according to claim 6, wherein the molded product having a hinge part is any one of a ferrite core cover, a cable tie, and a wire harness protection member.