JP2006306913A - Fire-retardant polyamide resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fire-retardant polyamide resin composition taking into consideration an environmental property, an economic property and a molding property, excellent in fire-retardancy, glow wire characteristics, tracking characteristics and low warping property, having less reduction of rigidity at suction and having an outstandingly highly uniform quality. <P>SOLUTION: In the fire-retardant polyamide resin composition, 100 pts.wt. of a polyamide resin (A) at least having a viscosity number of 70-130 ml/g; 0.5-20 pts.wt. of a triazine based fire-retardant agent (B); and 10-120 pts.wt. of calcium silicate fillers (C) are blended. The calcium silicate filler (C) has (i) loss on ignition of 1.7 wt.% or less and a sulfur content of 1,000 ppm or less and has (ii) an aspect ratio of 1.5-8 in the state that it is dispersed in the composition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a flame retardant polyamide resin composition. Specifically, it has excellent flame retardancy, glow wire characteristics, tracking characteristics, low warpage, little deterioration in rigidity at the time of water absorption, high balanced quality, low environmental impact, economical, electrical and electronic fields The present invention relates to a flame retardant polyamide resin composition suitable for materials for parts such as connectors and breaker electromagnetic switches.

  Conventionally, polyamide resins have been used in fields such as automobile parts, mechanical parts, and electric / electronic parts because they are excellent in mechanical strength, heat resistance, and the like. In particular, in electrical / electronic component applications, in recent years, there is a high demand for glow wire characteristics and tracking resistance characteristics represented by European IEC standards. In addition, as a trend of the times, non-halogen type hope has been made as a flame retardant.

The electromagnetic switch, which is an example of the electric / electronic component, is used as an important component of a control system in a wide range of fields such as a circuit used in an electronic application device such as a PLC and an inverter, and a capacitor load switching. Furthermore, as an example, a safety breaker, an amper breaker, and an earth leakage breaker: ELB (Earth Leakage Circuit Breaker), a circuit breaker for wiring: MCB (Miniature Circuit Breaker), MCCB (Molded Case Circuit Breaker-Need)
Breakers), breakers for motor protection (motor breaker), slim breakers (one-touch breaker, one-touch breaker), etc., when a current exceeding the specified level flows or when an abnormality such as shaking or heat is detected, It cuts off the energization. It is an electrical / electronic component that is built into electrical wiring, and is indispensable for ensuring the safety of electrical wiring. These electric / electronic parts use resin molded products to support the contacts, and these molded products need to withstand the heat generated at the contacts and the load caused by repeated movement of the contacts. It is one of the parts that require high physical properties with respect to mechanical strength, heat resistance, flame retardancy, dimensional stability, and the like.

  As a molded article satisfying the above physical properties, so-called thermoplastic engineering plastics having heat resistance are often used, and as additives for improving physical properties, means such as halogen flame retardants, fillers, fiber reinforcement are used. It has been studied and used to improve the physical property balance in combination. For example, in the above-described electromagnetic switch and breaker, polybutylene terephthalate (PBT) resin, polyphenol resin, polyepoxy resin, polyphenyl sulfide (PPS), liquid crystal polymer, etc. are conventionally used as resin molded products for contact support members and the like. Although it is more used, the resin alone has limitations in heat resistance, flame retardancy, and insulation properties, and in order to satisfy the required performance including cost, it is necessary to blend various additives such as flame retardant and reinforcing agent was there.

  As a method for imparting flame retardancy to a polyamide resin blended with a reinforcing agent, a method of compounding an antimony compound as an auxiliary agent with a halogenated aromatic compound-based flame retardant is generally used. However, when a halogen-based flame retardant is used, there is a possibility that the tracking resistance is lowered and the insulation characteristics cannot be maintained. In addition, halogen flame retardants generate corrosive hydrogen halide and smoke during combustion and are suspected of eliminating harmful substances. Due to these environmental problems, the use of plastic products containing halogen flame retardants is regulated. There is a movement to do.

  As flame retardants to replace halogen compounds, it is widely known to add hydrated metal compounds such as aluminum hydroxide and magnesium hydroxide. In order to obtain sufficient flame retardancy, these hydrated metals are used. It was necessary to add a large amount of the compound, so that the inherent properties of the polyamide were lost. On the other hand, phosphorus flame retardants such as red phosphorus and organic phosphorus compounds are also known, but there is a problem that the flame retardant bleeds out and corrodes the contact of the product.

  Patent Document 1 proposes a composition in which melamine cyanurate is blended with a polyamide resin as a non-halogen / non-phosphorus type flame retardant. However, Patent Document 1 only shows that an unreinforced polyamide resin composition containing melamine cyanurate has a high degree of flame retardancy that complies with flame retardancy standard V-0 in the UL94 test. The electrical properties are not described. In addition, although there is a description that a filler or other resin additive can be blended, there is no description of a composition that specifically blends the filler, and electrical properties such as flame retardancy and tracking resistance due to the filler are not described. The effect on characteristics is unknown.

  Various proposals have also been made for blending melamine cyanurate and reinforcing fillers in polyamide resins. Patent Document 2 discloses a flame retardant polyamide composition comprising melamine cyanurate or a derivative thereof and an inorganic filler. In order to satisfy the flame retardant standard V-2 in the UL94 test, it is stated that the present invention preferably contains an inorganic filler having an L / D of 4 to 1/4. Specifically, the relative viscosity (96% sulfuric acid is used). , Measured at 25 [deg.] C.) 3.1 medium viscosity polyamide 6 was blended with 10% by weight of melamine cyanurate and 30% by weight of inorganic fillers such as talc, kaolin and wollastonite with L / D = 1.2-2. Examples where the composition satisfies flame retardancy standard V-2 are shown, but there is no description of glow wire characteristics and tracking resistance characteristics, and no description of the surface treatment of the filler. The compositions described in the examples cannot satisfy the glow wire characteristics required in recent years.

  Patent Document 3 proposes a reinforced polyamide molding material containing 10 to 40% by weight of melamine and / or melamine cyanurate and unsized glass fiber, and the influence of the presence or absence of sizing of glass fiber on the glow wire characteristics is proposed. It is disclosed. However, according to the study by the present inventors, if crushed glass fibers that are not sized, that is, crushed glass fibers that have not been surface-treated, are used, the rigidity is significantly reduced during water absorption. Although there is a description of a short pulverized glass fiber, there is no clear description about the influence of the length of the glass fiber on the glow wire characteristics and tracking resistance characteristics. Regarding the relative viscosity of the polyamide used, there is only a description in the examples that polyamide 66 having a relative viscosity of 3.0 and polyamide 6 having a relative viscosity of 2.9 are used. There is no description on the impact on

  Patent Document 4 discloses a flameproof thermoplastic molding material comprising 1 to 50% by weight of a fibrous filler or acicular inorganic filler treated with polyamide, melamine cyanurate, and a silane compound having an arithmetic average fiber length of 70 to 200 μm. Is disclosed. Polyamide 6 having a viscosity number of 145 ml / g and polyamide 66 having a viscosity number of 151, melamine cyanurate 15 to 20% by weight, ground glass fiber (fiber length 135 to 144 μm) or average particle size 3.5 μm, L / D (aspect ratio) = An example in which 20% by weight of 9 wollastonite is blended is shown, showing the results of flammability, glow wire properties and mechanical properties. In the study by the present inventors, the composition described in the examples has a long filler fiber length (or a large aspect ratio) and a high polymer viscosity, so that recently required glow wire characteristics and tracking resistance characteristics are required. Can not be satisfied. Furthermore, with the filler aspect ratio and polymer viscosity of the present invention, a system having a large amount of filler cannot satisfy the glow wire characteristics and tracking resistance characteristics recently required. Further, since a filler having a relatively large aspect ratio is used, low warpage cannot be expected.

Patent Document 5 includes (A) 100 parts by weight of a polyamide resin, (B) 1 to 20 parts by weight of melamine cyanurate, and (C) 5 to 120 parts by weight of whisker made of a metal borate and resistance to tracking. A flame retardant polyamide resin composition having excellent properties is disclosed. In Examples and Comparative Examples, polyamide 66 having a relative viscosity of 2.4 was mixed with melamine cyanurate and borate whiskers (average length of 10-30 μm), potassium titanate whiskers (average length of 10-20 μm), calcium silicate whiskers (average) A composition in which a glass fiber (average length of 300 μm) is blended is shown.
However, in these documents, when calcium silicate filler is used. There is no mention of the effects of impurities in the filler.

JP-A-53-31759 JP-A-54-16565 Japanese Patent Publication No. 7-56008 Japanese National Patent Publication No. 11-513059 Japanese Patent Laid-Open No. 11-1613

  The present invention is environmentally friendly, economical and formable, has excellent flame retardancy, glow wire characteristics, tracking characteristics and low warpage, has little deterioration in rigidity during water absorption, and has a very highly balanced quality. It is to provide a flame retardant polyamide resin composition.

  In order to solve the above-mentioned problems, the present inventors use a relatively low molecular weight polyamide, and the glow wire characteristics, CTI depending on the blending amount of melamine cyanurate, the shape and impurity content of the calcium silicate filler. As a result of intensive studies on the influence on the properties, the inventors have found a delicate relationship among the purity, aspect ratio, and blending amount of the calcium silicate filler, and have reached the present invention. That is, the gist of the present invention is at least (A) 100 parts by weight of a polyamide resin having a viscosity of 70 to 130 ml / g, (B) 0.5 to 20 parts by weight of a triazine flame retardant, and (C) a calcium silicate filler. A composition comprising 10 to 120 parts by weight, wherein the (C) calcium silicate filler (i) has an ignition loss of 1.7% by weight or less and a sulfur content of 1000 ppm or less, (ii ) It exists in the flame-retardant polyamide resin composition characterized by having an aspect ratio in the range of 1.5-8 in the state disperse | distributed in the composition, and a molded article obtained from it.

  The polyamide resin composition of the present invention is an electrically insulating material that is excellent in flame retardancy, glow wire characteristics, and tracking resistance characteristics, suppresses a decrease in rigidity due to water absorption, is excellent in mechanical strength and low warpage, and is poorly molded. This is particularly useful as a material for electrical and electronic parts. Moreover, since the composition of the present invention does not contain a halogen-based flame retardant, the environmental load is small, and an expensive filler is not used, which is economical.

  Hereinafter, the present invention will be described in detail. As the (A) polyamide resin used in the present invention, a polyamide obtained by polycondensation of a lactam having three or more members or ω-amino acid, or polycondensation of a dibasic acid and a diamine can be used. Specifically, polymers such as ε-caprolactam, aminocaproic acid, enanthractam, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 9-aminononanoic acid, α-pyrrolidone, α-piperidone, hexamethylenediamine, nonamethylene Obtained by polycondensation with diamines such as diamine, undecamethylenediamine, dodecamethylenediamine, metaxylylenediamine, and dicarboxylic acids such as terephthalic acid, isophthalic acid, adipic acid, sebacic acid, dodecanedioic acid, and glutaric acid. Polymers or copolymers thereof are mentioned, and more specifically, nylon 4, 6, 7, 8, 11, 12, 6, 6, 6, 9, 6, 10, 6, 11, 6, 12. , 6T, 6/6 · 6, 6/12, 6 / 6T, 6T / 6I, MXD6, and the like. These may be used alone or in combination. Particularly preferred polyamide resins in the present invention include polyamide 6, copolymer polyamide 6/66 or 66/6, and polyamide 6 or polyamide 66 as a main component from the viewpoint of flame retardancy, mechanical strength, and moldability. Or the polyamide 66 is mentioned. More preferably, polyamide 6 is the main component because the moldability can be maintained. The terminal of the polyamide resin in the present invention may be sealed with a carboxylic acid or an amine compound also for molecular weight adjustment.

  The polyamide resin used in the present invention has a polymerization degree within a certain range, that is, a viscosity number within a specific range. (A) The viscosity number of the polyamide resin is 70 to 130 ml / g, preferably 72 to 120 ml / g, as measured at 96% sulfuric acid concentration 1% and a temperature of 23 ° C. When the viscosity number is lower than 70 ml / g, the melt strength is small, so that the mechanical strength is lowered. Further, if the viscosity number is higher than 130 ml / g, the glow wire characteristic (GWFI) is likely to have a longer combustion time after contact with the rod, that is, it may be rejected, which makes it difficult to satisfy the required characteristics for various applications. Absent.

  Examples of the (B) triazine flame retardant used in the present invention include compounds represented by the following general formula (1) or (2), melamines, and melamine cyanurate.

(Wherein R ^{1 to} R ⁶ each represent a hydrogen atom or an alkyl group).
Specific examples of the compound represented by the general formula (1) include cyanuric acid, trimethyl cyanurate, triethyl cyanurate, tri (n-propyl) cyanurate, methyl cyanurate, diethyl cyanurate and the like. Specific examples of the compound represented by the general formula (2) include isocyanuric acid, trimethyl isocyanurate, triethyl isocyanurate, tri (n-propyl) isocyanurate, diethyl isocyanurate, methyl isocyanurate and the like.

Examples of melamines include melamine, melamine derivatives, compounds having a structure similar to melamine, and melamine condensates. Specific examples of melamines include melamine, ammelide, ammelin, formoguanamine, guanylmelamine, cyanomelamine, arylguanamine, melam, melem, melon and the like.
Examples of melamine cyanurate include equimolar reaction products of cyanuric acid and melamine. Moreover, some of the amino groups or hydroxyl groups in melamine cyanurate may be substituted with other substituents. Melamine cyanurate can be obtained, for example, by mixing an aqueous solution of cyanuric acid and an aqueous solution of melamine, reacting at 90 to 100 ° C. with stirring, and filtering the produced precipitate, and is a white solid. It is preferable to use after pulverizing into a powder form. Of course, a commercially available product can be used as it is or after being pulverized.

  Preferred examples of the (B) triazine-based flame retardant used in the present invention include cyanuric acid, isocyanuric acid, melamine, melamine cyanurate, melem cyanuric acid, and the decomposition product is raised on the surface of the molded product. Since there is no inconvenience such as blooming, an equimolar reaction product of cyanuric acid represented by melamine cyanurate and melamine is more preferable. However, since melamine cyanurate starts to decompose at 260 ° C. or higher, it is necessary to avoid the molding temperature at 260 ° C. or higher in order to suppress the occurrence of molding defects and ensure flame retardancy. As in the present invention, in the case where an inorganic filler is blended and the fluidity tends to decrease, a polyamide resin whose main component is polyamide 6 that can ensure flame retardancy by making the molding temperature as low as 260 ° C. is used. It is preferable.

  The compounding amount of the triazine-based flame retardant is 0.5 to 20 parts by weight with respect to 100 parts by weight of the polyamide resin. If the amount of the triazine flame retardant is less than 0.5 parts by weight, a flame retardant effect is not expected. When the amount is more than 20 parts by weight, it is easy to disassemble at the time of molding and mold contamination becomes a problem. The blending amount of the triazine-based flame retardant is preferably 1 to 15 parts by weight, more preferably 1.5 to 10 parts by weight, from the viewpoint of the balance between flame retardancy and glow wire characteristics, tracking resistance characteristics and mechanical characteristics. It is.

The (C) calcium silicate-based filler used in the present invention is calcium silicate known as a resin filler, and any impurities whose amount is less than a specific value or whose aspect ratio is in a specific range can be used. A typical example is a white needle-like crystal mineral known as wollastonite. Wollastonite can be obtained from a natural white mineral having needle-like crystals, the main component of which is calcium silicate, by pulverizing and classifying it. Of course, synthesized wollastonite should also be used in the present invention. Can do. These wollastonites are substantially represented by the chemical formula CaO.SiO ₂ and contain about 50 wt% SiO ₂ , about 47 wt% CaO, and other impurities such as Fe ₂ O ₃ , Al ₂ O ₃ , CaCO _3. The specific gravity is known to be about 2.9.
In addition, in the sense that the Hunter whiteness is 60 or more and the weather resistance to the polyamide is not deteriorated, a slurry having a pH value of 6 to 8 when made into 10% slurry in high purity water is more preferable. The present inventors have found that some impurities present in wollastonite, particularly natural minerals, affect flame retardancy, etc., and flame retardancy is improved by suppressing the content of these impurities. Succeeded.

The calcium silicate used in the present invention has a loss on ignition measured by the following method of 1.7% by weight or less. The present inventors have found that calcium silicate having a loss on ignition of 1.7% by weight or less is excellent in electrical insulating properties and flame retardancy. The ignition loss is more preferably 1.6% by weight or less, and further preferably 1.5% by weight or less.
The ignition loss of calcium silicate in the present invention means that calcium silicate is heat-treated at 110 ° C. for 6 hours to remove moisture, and then allowed to cool to room temperature in a desiccator (with a desiccant). (Thermogravimetric Analysis: Thermogravimetric Analysis) Using a measuring device, the temperature is continuously raised to 1300 ° C. at 10 ° C./min, and the weight reduction value at the time when the temperature reaches 1300 ° C. is calculated and used as ignition loss. The weight loss due to the strong heat treatment is considered to be CO ₂ derived from CaCO ₃ contained in calcium silicate as an impurity in a trace amount.

Furthermore, the calcium silicate used in the present invention has a sulfur content of 1000 ppm or less. The present inventors have found that calcium silicate having a sulfur content of 1000 ppm or less is excellent in electrical insulation characteristics and flame retardancy characteristics. The sulfur content is more preferably 700 ppm or less, and further preferably 500 ppm or less.
In the present invention, the sulfur content of calcium silicate refers to the combustion of calcium silicate that has been heat-treated at 110 ° C. for 6 hours to remove moisture and then allowed to cool to room temperature in a desiccator (with a desiccant). It analyzes with a sulfur oxide analyzer (Oxides of sulfur analyzer), calculates sulfur content from the amount of sulfur dioxide contained in combustion gas, and makes it sulfur content in calcium silicate.

  In addition, calcium silicate has an aspect ratio of 1.5 to 8 in a state dispersed in the composition. The method for measuring the aspect ratio (fiber length and fiber diameter) of calcium silicate is as follows. The fiber length is measured by adding an appropriate amount of calcium silicate obtained by heating the composition pellets in an electric furnace at 500 ° C. for 30 minutes for complete ashing to a 3% neutral detergent solution, stirring, and so on. The obtained calcium silicate dispersion was collected on a glass plate with a pipette and photographed using a stereomicroscope. With respect to the photographic image, the maximum dimension and the minimum dimension for each of 1000 individual calcium silicate fibers were measured using a digitizer. The average fiber length (L) is obtained by dividing the total amount of the maximum dimensions by the number. The minimum dimension is the diameter perpendicular to the fiber, and the average diameter (D) was measured by dividing the total amount by the number. The aspect ratio is indicated by L / D, and L / D = 1.5 to 8, more preferably 2 to 7.

  When the aspect ratio of calcium silicate dispersed in the pellet is 1.5 or less, the effect of improving the strength is small, and when it is larger than 8, the combustibility, the glow wire characteristic and the tracking resistance characteristic are deteriorated.

  (C) The compounding quantity of a calcium-silicate type filler is 10-120 weight part with respect to 100 weight part of (A) polyamide resin, Preferably it is 15-115 weight part, More preferably, it is 20-110 weight part. It is. If the amount of calcium silicate is less than 10 parts by weight, the mechanical properties are not exhibited. If the amount is more than 120 parts by weight, the burning time after contact with the glow wire characteristic (GWFI) becomes long, and it becomes unacceptable.

(C) Calcium silicate, such as wollastonite, is used after being pulverized in advance. Various types of pulverizers can be used, and examples thereof include a high-speed rotary mill, a ball mill, a medium stirring mill, and a jet mill. Among these, a jet mill is preferable. Further, examples of such a jet mill include an air current suction type, a collision object collision type, an opposed jet collision type, and a composite type. Among them, an opposed jet collision type pulverizer is preferable.
Furthermore, it is preferable to use a wollastonite fiber in which the fiber length distribution is controlled by classifying the pulverized wollastonite to remove components having a long fiber length. Such classification methods include mesh-type sieves, impact type inertial force classifiers (variable impactors, etc.), Aanda effect type inertial force classifiers (elbow jets, etc.), spiral airflow type centrifugal fields. Classifiers (multistage cyclones, etc.), helical airflow type centrifugal field classifiers with free pan type and guide vanes (microplex, dispersion separator, etc.), helical airflow type centrifugal field classifiers, forced pan type In addition, a rotary blade type (micron separator, super separator, etc.) can be used, and the use of a composite type of these is also preferable (the names in parentheses are trade names or common names). Of these, a centrifugal field classifier is preferable as a finer particle classifier.

(C) The calcium silicate filler is preferably surface-treated. In other words, using calcium silicate filler pretreated with a coupling agent such as an isocyanate compound, an organic silane compound, an organic titanate compound, an organic borane compound, or an epoxy compound can be used during absolutely dry or water absorption. In the sense of obtaining better mechanical strength, it is preferable. In particular, when the aspect ratio of the filler is small as in the present invention, the effect of improving the mechanical strength, particularly the elastic modulus, is small unless a coupling agent is blended. However, in the tracking resistance test, a surface treatment agent containing a low molecular weight organic component on the surface of the filler tends to form a conductive path, and tends to deteriorate the tracking resistance characteristics. Therefore, it is necessary to select a coupling agent (surface treatment agent) for the filler in balance with mechanical strength, warpage (smoothness of the molding surface), and the like.

  Particularly preferred surface treatment agents are silane coupling agents (organosilane compounds), and specific examples thereof include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- Epoxy group-containing alkoxysilane compounds such as (3,4-epoxycyclohexyl) ethyltrimethoxysilane; mercapto group-containing alkoxysilane compounds such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane; γ-ureidopropyltri Ureido group-containing alkoxysilane compounds such as ethoxysilane, γ-ureidopropyltrimethoxysilane, γ- (2-ureidoethyl) aminopropyltrimethoxysilane; γ-isocyanatopropyltriethoxysilane, γ-isocyanatopropi Trimethoxysilane, γ-isocyanatopropylmethyldimethoxysilane, γ-isocyanatopropylmethyldiethoxysilane, γ-isocyanatopropylethyldimethoxysilane, γ-isocyanatopropylethyldiethoxysilane, γ-isocyanatopropyltrichlorosilane, etc. Isocyanato group-containing alkoxysilane compounds; amino group-containing alkoxysilanes such as γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, and γ-aminopropyltrimethoxysilane Compound; hydroxyl group-containing alkoxysilane compound such as γ-hydroxypropyltrimethoxysilane, γ-hydroxypropyltriethoxysilane; γ-methacryloxypropyltrimethoxysilane, vinyl Trimethoxysilane, N-β- (N- vinylbenzylaminoethyl) such -γ- aminopropyltrimethoxysilane hydrochloride carbon-carbon unsaturated group-containing alkoxysilane compounds, and the like. In particular, γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ-amino Propyltrimethoxysilane is preferably used, but is not limited thereto.

  As a method for using the surface treating agent, a method of pretreating a calcium silicate filler in advance and then melt-kneading with a polyamide resin in accordance with a conventional method is preferably used. An untreated calcium silicate filler and (A) When melt-kneading a polyamide resin, (B) triazine flame retardant, etc., a so-called integral blend method in which a surface treatment agent such as a silane coupling agent is added at the same time may be used, but is not limited thereto. is not.

  The amount of the silane coupling agent in the composition of the present invention is 0.01 to 2 parts by weight with respect to 100 parts by weight of the (A) polyamide resin. When it is used in an amount of 2 parts by weight or more, the tracking resistance and flame retardancy are significantly reduced. On the other hand, in the case of 0.01 parts by weight or less, the effect of improving the mechanical strength, particularly the elastic modulus is small.

  The production method of the composition of the present invention is not particularly limited, and the components (A) to (C) and other components to be blended as necessary may be blended, melted and kneaded. . (A) The polyamide resin is blended with (B) a triazine flame retardant, (C) a calcium silicate filler, and (D) a silane coupling agent. This can be done by various means known at the stage. The simplest method is a method of simply dry blending a polyamide resin, a triazine flame retardant and filler, and a silane coupling agent (or a filler that has been surface-treated with a silane coupling agent in advance). The resulting dry blend is pelletized by melt mixing extrusion. In melt mixing extrusion, it is preferable to supply a polyamide resin, a triazine flame retardant, a filler, and a silane coupling agent from the main hopper port of the extruder because stable mixing is possible. Alternatively, only the filler and the silane coupling agent may be supplied from the side feed port. As another method, a master pellet prepared by kneading more than a predetermined amount of a triazine flame retardant or filler with a polyamide resin is prepared in advance, and this is dry-blended with a dilution polyamide resin. Although a polyamide resin composition can be obtained, it is not limited to these.

  In addition to the components (A) to (C) or (A) to (D) described above, the resin composition of the present invention may contain other components as necessary within a range that does not impair the effects of the present invention. it can. Examples of the components to be blended include pigments, dyes, nucleating agents, mold release agents, stabilizers, antistatic agents and other known additives. In particular, an amide type release agent such as a carboxylic acid amide type wax or a bisamide compound of ethylene bisstearylamide is used as a flame retardant dispersion, for example, 0.001 to 0.5 parts by weight with respect to 100 parts by weight of the polyamide resin, It is more preferable to add 0.005 to 0.3 parts by weight because the productivity at the time of injection molding without lowering the flame retardancy, glow wire characteristics, and tracking resistance characteristics is increased.

The carboxylic acid amide wax is obtained by a dehydration reaction of a mixture of a higher aliphatic monocarboxylic acid and a polybasic acid and a diamine. As the raw material higher aliphatic monocarboxylic acid, saturated aliphatic monocarboxylic acid having 16 or more carbon atoms and hydroxycarboxylic acid are preferable, for example, palmitic acid, stearic acid, behenic acid, montanic acid, 12-hydroxystearic acid and the like. Can be mentioned.
The raw material polybasic acid is a dibasic acid or higher carboxylic acid, for example, malonic acid, succinic acid, adipic acid, sebacic acid, pimelic acid, azelaic acid and other aliphatic dicarboxylic acids, phthalic acid, terephthalic acid, etc. And alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and cyclohexylsuccinic acid. Examples of the diamine include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, hexamethylenediamine, metaxylylenediamine, tolylenediamine, paraxylylenediamine, phenylenediamine, and isophoronediamine. .

  When producing a carboxylic acid amide wax, one having an arbitrary softening point can be obtained by changing the mixing ratio of the polybasic acid to the higher aliphatic monocarboxylic acid to be used. The carboxylic acid amide wax used in the composition of the present invention preferably has a polybasic acid mixing ratio of 0.18 mol to 1.0 mol with respect to 2 mol of the higher aliphatic monocarboxylic acid. The amount of diamine used is preferably in the range of 1.5 mol to 2.0 mol with respect to 2 mol of the higher aliphatic monocarboxylic acid, and varies according to the amount of polybasic acid used.

Bisamide compounds include diamine and fatty acid compounds such as N, N′-methylenebisstearic acid amide and N, N′-ethylene bisstearic acid amide, or dioctadecyl diamides such as N, N′-dioctadecyl terephthalic acid amide. Mention may be made of basic acid amides.
The compounding quantity of an amide-type wax or a bisamide compound is 0.01-0.5 weight part with respect to 100 weight part of (A) polyamide resin.

The polyamide resin composition of the present invention can produce various application parts by a known molding method of thermoplastic resins. Preferably, an injection molding method in which the polyamide resin composition such as the dry blend and pellets is supplied to various molding machines such as an injection molding machine, poured into a mold, cooled, and taken out is limited to this method. It is not something.
Although it does not specifically limit as a molded object of this invention, For example, a breaker housing | casing, a cover, a separator, a handle, etc. are mentioned.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not restrict | limited to a following example, unless the summary is exceeded. In addition, each component used in the following examples and the evaluation test method of the obtained composition are as follows. The characteristics of wollastonite are summarized in Table-1.
<Raw ingredient>

A-1) Polyamide 6: viscosity number = 87 ml / g, “Novamid 1005J” manufactured by Mitsubishi Engineering Plastics.
A-2) Polyamide 6: viscosity number = 99 ml / g, “Novamid 1007J” manufactured by Mitsubishi Engineering Plastics.
A-3) Polyamide 6: viscosity number = 150 ml / g, “Novamid 1015J” manufactured by Mitsubishi Engineering Plastics.
A-4) Polyamide 66: Viscosity number = 118 ml / g, “Amilan E-3000” manufactured by Toray Industries, Inc.
B) Melamine cyanurate: “MX44” manufactured by Ogaki Kasei Co., Ltd.

C-1) Wollastonite A: “NYAD400-10023” manufactured by NYCO
C-2) Wollastonite B: “NYAD325” manufactured by NYCO.
C-3) Wollastonite C: “NYGLOS M3” manufactured by NYCO.
C-4) Wollastonite D: “NYGLOS 8-10013” manufactured by NYCO.
C-5) Wollastonite E: “NYGLOS 8” manufactured by NYCO.
C-6) Wollastonite F: “NYGLOS 4-10013” manufactured by NYCO.
C-7) Wollastonite G: “NYGLOS 4” manufactured by NYCO

D) Silane coupling agent: γ-aminopropyltriethoxysilane, manufactured by Nihon Unicar “A1100”
E-1) Carboxylic acid amide wax releasing agent: “WH255” manufactured by Kyoeisha Chemical Co., Ltd.
E-2) Polyethylene wax release agent “High Wax 110P manufactured by Mitsui Chemicals”.
<Physical property testing method and evaluation method>

* Viscosity number: 1% dissolved in 96% concentrated sulfuric acid solvent according to JIS K6933-99 and measured at 23 ° C.
* Flame retardancy: Test method UL-94 using a test piece of 5 × 1/2 × 1/32 (inch)
It carried out according to the standard.
* Glow wire characteristics (GWFI): Test method IEC60 using a test piece with a thickness of 1.6 mm
It measured based on 695-2-12, and it was set as the pass if the standard was satisfied at 960 degreeC.
* Tracking resistance (CTI): Test method IEC601 using a test piece with a thickness of 3.0 mm
12 was measured. The applied voltage was implemented in units of 50V.

* Mechanical stiffness (rigidity when absolutely dry): An absolutely dry tensile test piece molded according to ISO 527 is ISO5
27, the tensile modulus was measured.
(Rigidity at the time of water absorption): An ISO527 tensile test piece was immersed in water at 23 ° C. for 2 weeks, conditioned at 95% humidity for 1 week, and the tensile elastic modulus was measured according to ISO527.
* Water absorption: It was determined from the weight difference between tensile test pieces before and after immersion humidity control.
* Warp: A 100φ × 1.6 mmt disc was molded, the amount of warp was visually observed, and the following criteria were evaluated.
○: Small amount of warping △: Medium amount of warping ×: Large amount of warping

[Examples 1 to 9 and Comparative Examples 1 to 11]
After blending the polyamide resin and various additives at a blending ratio shown in Table-1 or Table-2 (unit is part by weight), using a TEX30HCT type twin screw extruder manufactured by Nippon Steel Works, the cylinder temperature is 240-270 ° C, Pellets of polyamide resin composition were obtained by melt-kneading under the condition of a screw speed of 200 rpm. The obtained pellets were dried and then injection molded at a cylinder temperature of 240 to 270 ° C. and a mold temperature of 80 ° C. using a J75ED molding machine manufactured by Nippon Steel, and each test piece for the above test was produced. . Flammability, GWFI, CTI and mechanical stiffness were evaluated according to the methods described above. The evaluation results are shown in Table-1 or Table-2.

As shown in Examples 1 to 8, a composition in which a polyamide having a specific viscosity number range, wollastonite having a specific aspect ratio and impurity content is surface-treated in advance or blended with a silane coupling agent is used as a filler. Flame retardant, glow wire characteristics (GWFI), tracking resistance characteristics even if the content is blended in a large amount of about 50% by weight in the total composition, and triazine flame retardant is about 3% by weight. It is excellent in (CTI) and the rigidity reduction at the time of water absorption is suppressed, and the quality balance is extremely excellent.
Example 9 uses untreated wollastonite and does not contain a silane coupling agent. Therefore, the rigidity is greatly reduced at the time of water absorption, but flame retardancy, glow wire characteristics (GWFI), tracking resistance characteristics (CTI) ) Is excellent.

  On the other hand, as shown in Comparative Examples 1-7, when the ignition loss of wollastonite is large and the sulfur content is large, or when the aspect ratio is large, the composition has a filler content of about 50% by weight in the total composition. %, The amount of flame retardant is about 3% by weight, the glow wire characteristic (GWFI) is rejected, and the tracking resistance characteristic (CTI) is also 400 to 450V. Even in the case of such wollastonite, the compositions of Comparative Examples 6 to 8 having a small blending amount pass the glow wire characteristics, but the tracking resistance does not reach that of the example compositions. In addition, in the case of Comparative Example 9 using a polyamide resin having a large viscosity number and Comparative Example 10 using a large amount of wollastonite, the glow wire characteristics are also rejected. In Comparative Example 11, the influence of the difference in the type of release agent was confirmed. By using polyethylene wax in place of the amide wax in the formulation of Example 8, combustibility, glow wire characteristics (GWFI), Tracking resistance characteristics (CTI) are affected.

The composition of the present invention is a polyamide resin composition excellent in flame retardancy, glow wire characteristics, and tracking characteristics, and is suitable for electrical and electronic parts such as safety breakers incorporated in electrical wiring and earth leakage circuit breakers. Since there is little decrease in rigidity during moisture absorption and the warp is low, it can be used even for mechanical parts that have a particularly high mechanical load.

Claims (5)

  At least (A) 100 parts by weight of a polyamide resin having a viscosity of 70 to 130 ml / g, (B) 0.5 to 20 parts by weight of a triazine flame retardant, and (C) 10 to 120 parts by weight of a calcium silicate filler are blended. The (C) calcium silicate filler is (i) a loss on ignition of 1.7% by weight or less, a sulfur content of 1000 ppm or less, and (ii) a state in which it is dispersed in the composition. A flame retardant polyamide resin composition having an aspect ratio in the range of 1.5 to 8.   Furthermore, 0.01-2 weight part is mix | blended with (D) silane coupling agent, The flame-retardant polyamide resin composition of Claim 1 characterized by the above-mentioned.   The flame retardant polyamide resin composition according to claim 1 or 2, wherein the (A) polyamide resin is a polyamide resin having a polyamide 6 resin or a polyamide 66 resin as a main structural unit.   The amide type release agent selected from (E) amide type wax or bisamide is further blended in an amount of 0.01 to 0.5 parts by weight per 100 parts by weight of the (A) polyamide resin. 4. The flame retardant polyamide resin composition according to any one of 3 above. Electrical / electronic equipment parts formed by molding the polyamide resin composition according to claim 1.