JP2017061674A - Polyamide resin composition and molded article thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide resin composition having flame retardancy and hinge characteristics, and improved variation in the hinge characteristics, and to provide a molded article thereof.SOLUTION: A polyamide resin composition contains (A) a polyamide 66/6 copolymer and/or a polyamide 66 resin, (B) a polyamide 6 resin and (C) a melamine cyanurate flame retardant, where the polyamide resin composition contains 4 to 8 pts.mass of the component (C) with respect to 100 pts.mass of the total of the components (A) and (B), a mass ratio of the polyamide 66 unit/polyamide 6 unit of the polyamide resin composition is 88/12 to 73/27, 98% sulfuric acid relative viscosity ηr (according to JIS K6920) of the polyamide resin composition is 2.50 to 2.83, and an average particle size of the component (C) in the polyamide resin composition is set at 1.0 μm or less.SELECTED DRAWING: None

Description

  The present invention relates to a polyamide resin composition, and particularly relates to a polyamide resin composition excellent in flame retardancy and hinge characteristics and a molded product thereof.

  Polyamide resins have excellent properties in molding processability and the like including mechanical properties, and thus have been widely used for various parts such as automobile parts, electronic / electric parts, and industrial machine parts. Since it is particularly excellent in toughness, it is used in products having hinge parts such as connectors and clips. In many cases, these products require flame retardancy. In particular, it is desired to use a non-halogen flame retardant from an environmental viewpoint.

  A typical example of such a flame-retardant polyamide resin is a flame-retardant polyamide material using melamine cyanurate, and is used for, for example, connectors and clips in the field of electrical and electronic fields (see Patent Documents 1 and 2). ). Patent Documents 3 and 4 propose a method in which a master batch having a high concentration of melamine cyanurate is prepared in advance, and this is mixed with a polyamide resin by a molding machine or the like and molded. Patent Document 5 proposes blending a specific dispersant at the stage of mixing a polyamide resin and melamine cyanurate.

JP 53-125959 A JP-A-53-031759 Japanese Patent Laid-Open No. 08-245875 Japanese Patent Laid-Open No. 11-302533 JP 2003-301104 A

The flame-retardant polyamide resin using melamine cyanurate is filled in the composition in a form in which melamine cyanurate is not sufficiently compatible with the polyamide resin and is dispersed like an inorganic filler. For this reason, the polyamide resin composition filled with melamine cyanurate tends to have lower toughness. Conventional techniques such as producing a master batch or dispersing with a dispersant cannot achieve a balance between flame retardancy and hinge characteristics, which are contradictory performances.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a polyamide resin composition not only excellent in flame retardancy and hinge characteristics but also improved in variation in hinge characteristics.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has made a resin composition containing a polyamide resin and melamine cyanurate within a specific range, a 98% sulfuric acid relative viscosity ηr of the polyamide resin composition, It was found that by setting the average particle size of the melamine cyanurate within a predetermined range, excellent flame retardancy and hinge characteristics were given, and the present invention was completed.

That is, the polyamide resin composition of the present invention is
A polyamide resin composition comprising (A) a polyamide 66/6 copolymer and / or a polyamide 66 resin, (B) a polyamide 6 resin and (C) a melamine cyanurate flame retardant, wherein the component (A) and (B ) 4 to 8 parts by mass of the flame retardant (C) component with respect to a total of 100 parts by mass of the component, the mass ratio of polyamide 66 units / polyamide 6 units in the polyamide resin composition is 88/12 to 73/27, The polyamide resin composition has a 98% sulfuric acid relative viscosity ηr (based on JIS K6920) of 2.50 to 2.83, and the average particle size of the component (C) in the polyamide resin composition is 1.0 μm or less.

(D) 0.1-1.0 mass part of surfactant containing the fatty acid ester of at least 1 type of polyalkylene polyhydric alcohol is further included with respect to a total of 100 mass parts of (A) component and (B) component. It is preferable.
The polyamide 66/6 copolymer as the component (A) preferably comprises 50 to 95% by mass of polyamide 66 units and 5 to 50% by mass of polyamide 6 units.
The component (A) preferably has a 98% sulfuric acid relative viscosity ηr (based on JIS K6920) of 2.3 to 2.9.
The component (B) preferably has a 98% sulfuric acid relative viscosity ηr (based on JIS K6920) of 2.1 to 2.7.
The 98% sulfuric acid relative viscosity ηr (based on JIS K6920) of the polyamide resin composition is more preferably 2.50 to 2.70.

  (D) component is polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene distearate, polyoxyethylene monooleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate, It is preferably at least one selected from the group consisting of polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate and polyoxyethylene sorbitan trioleate.

The molded article of the present invention is formed by molding the polyamide resin composition of the present invention.
The molded body may be a connector part having a hinge portion.
The molded body may be a clip.

  The polyamide resin composition of the present invention is a polyamide resin composition comprising (A) a polyamide 66/6 copolymer and / or a polyamide 66 resin, (B) a polyamide 6 resin and (C) a melamine cyanurate flame retardant. In addition, 4 to 8 parts by mass of the (C) component is included with respect to 100 parts by mass of the total of the (A) component and the (B) component, and the mass ratio of polyamide 66 units / polyamide 6 units in the polyamide resin composition is 88. / 12-73 / 27, 98% sulfuric acid relative viscosity ηr (according to JIS K6920) of the polyamide resin composition is 2.50-2.83, and the average particle size of the component (C) in the polyamide resin composition is 1.0 μm. Since it is the following, flame retardancy and hinge characteristics can be improved without impairing the mechanical properties, chemical resistance, good moldability, electrical properties, etc. inherent to the polyamide resin composition Can, appliance parts, electronic parts, can be suitably used in applications such as automotive parts.

It is a top view of the molded product used for the test of a hinge characteristic. It is a side view of the molded product used for the test of a hinge characteristic.

Hereinafter, the present invention will be described in detail.
[Polyamide resin composition]
The polyamide resin composition of the present invention is a polyamide resin composition comprising (A) a polyamide 66/6 copolymer and / or a polyamide 66 resin, (B) a polyamide 6 resin and (C) a melamine cyanurate flame retardant. Then, with respect to a total of 100 parts by mass of the component (A) and the component (B), the component (C) contains 4 to 8 parts by mass, and the mass ratio of polyamide 66 units / polyamide 6 units in the polyamide resin composition is 88 / 12-73 / 27, the polyamide resin composition has a 98% sulfuric acid relative viscosity ηr (according to JIS K6920) of 2.50-2.83, and the average particle size of the component (C) in the polyamide resin composition is 1. 0 μm or less.
Hereinafter, each component will be described in detail.

[(A) component: polyamide 66/6 copolymer and / or polyamide 66 resin]
The polyamide 66 resin is a polymer having an amide bond (—NHCO—) in the main chain and comprising hexamethylene units and adipic acid units. The polyamide 66 resin is not particularly limited. For example, a polymer obtained by polycondensation of hexamethylenediamine and adipic acid, a polymer obtained by polycondensation of 6-aminocapronitrile and adipic acid, Examples thereof include a polymer obtained by polycondensation of hexamethylenediamine and adipoyl chloride, and a polymer obtained by polycondensation of 6-aminocapronitrile and adipoyl chloride. Of these, a polymer obtained by polycondensation of hexamethylenediamine and adipic acid is preferred because of the availability of raw materials.

The polyamide 66/6 copolymer is a copolymer of polyamide 66 units and polyamide 6 units, and is preferably a polyamide 66 comprising 50 to 95% by mass of polyamide 66 units and 5 to 50% by mass of polyamide 6 units. / 6 copolymer, more preferably a polyamide 66/6 copolymer comprising 80 to 90% by mass of polyamide 66 units and 10 to 20% by mass of polyamide 6 units.
By using such a polyamide resin, the flame retardancy and hinge characteristics of the polyamide resin composition of the present invention can be further improved. Moreover, it is preferable also from a compatible viewpoint with the below-mentioned (B) polyamide 6 resin.

  The relative viscosity measured at 25 ° C. in a 98% sulfuric acid concentration of 1% according to JIS K6920 of component (A) is preferably in the range of 2.3 to 2.9, and in the range of 2.3 to 2.8. More preferred. By setting the relative viscosity of the component (A) to 2.3 or more, the toughness and mechanical strength of the molded body can be further improved. Further, by setting the relative viscosity to 2.9 or less, flame retardancy and molding of the molded body can be further facilitated, and the appearance can be improved.

  Component (A) is a copper compound containing copper acetate or copper iodide (potassium iodide may be used in combination) as a component, a hindered phenol heat stabilizer, a hindered amine heat stabilizer. Further, it is preferable to obtain a heat-stable prescription by adding an organic heat stabilizer such as a phosphorus heat stabilizer. Thereby, the thermal stability of the polyamide resin composition of the present invention can be further improved.

  The above heat-stable prescription may be carried out in any manufacturing process. For example, copper acetate, copper iodide and an organic heat stabilizer may be added to the monomer, and then polymerization may be performed. After obtaining a polymer by polymerization, in a processing step using an extruder or a molding machine It may be added to the molten polyamide resin. Alternatively, it may be directly mixed with polymer pellets and then subjected to a molding process.

[(B) component: polyamide 6 resin]
The (B) polyamide 6 resin contained in the polyamide resin composition of the present invention is necessary for developing the high hinge characteristics of the polyamide resin composition. The amount of the component (B) is not particularly limited, but the mass ratio of polyamide 66 units / polyamide 6 units in the polyamide resin composition is 88/12 to from the viewpoints of hinge characteristics and variation in hinge characteristics and mechanical characteristics. 73/27, preferably 88/12 to 75/25, and more preferably 86/14 to 75/25. By setting the mass ratio of the polyamide 6 to 12 or more, the hinge characteristics can be further improved, and by setting the mass ratio to 27 or less, the compatibility with the component (A) can be made sufficiently, and the hinge characteristics can be obtained. It is possible to improve the effect of suppressing the variation.

  The relative viscosity measured at 25 ° C. in a 98% sulfuric acid concentration of 1% according to JIS K6920 of component (B) is preferably in the range of 2.1 to 2.7, and in the range of 2.4 to 2.6. More preferred. By setting the relative viscosity of component (B) to 2.1 or more, the hinge characteristics, toughness, mechanical strength, and flame retardancy of the molded product can be further improved. When the relative viscosity is 2.7 or less, the flame retardancy of the molded product can be further improved, and the appearance can be improved.

[(C) component: melamine cyanurate flame retardant]
The component (C) contained in the polyamide resin composition of the present invention is a reaction product of melamine or a derivative thereof and cyanuric acid or a derivative thereof, and is not particularly limited as long as it is such a reaction product. Component (C) is, for example, added melamine or a derivative thereof in an aqueous solution of cyanuric acid or a derivative thereof, stirred at about 90 to 100 ° C., filtered and dried the precipitate obtained as a reaction product, It can be produced by pulverizing into a fine powder.

  A preferred component (C) is melamine cyanurate, which is an equimolar reaction product of melamine and cyanuric acid. Melamine cyanurate may contain 0.001% by mass or more and 0.30% by mass or less of unreacted melamine or cyanuric acid. Such melamine cyanurate is commercially available. In the present invention, commercially available melamine cyanurate can be used as appropriate.

  The component (C) exhibits a dispersed state dispersed in the component (A) and the component (B). Therefore, the average particle diameter in the polyamide resin composition of (C) component can observe a resin composition cross section using a scanning electron microscope (SEM). More specifically, the polyamide resin composition is cut, and the cut surface is observed using a scanning electron microscope (SEM). When the observation target is a cylindrical pellet shape, the observation direction is cut and observed in a cross section substantially perpendicular to the long side of the pellet. In the case of a molded piece, the cross section is observed perpendicular to the flow direction. When the particle of component (C) is not spherical, the diameter passing through the center of gravity of the particle is measured in increments of 2 °, and the average value is taken as the particle size of the particle. The average particle diameter is an average value of dispersed particles measured by an image analyzer (image analysis software).

The average particle size of the component (C) in the polyamide resin composition is 1.0 μm or less. By setting the average particle size in the polyamide resin composition of component (C) to 1.0 μm or less, the tensile elongation, hinge characteristics, low temperature hinge, etc. of the resin composition can be improved.
The average particle size of the component (C) in the polyamide resin composition may be any method as long as it can be controlled to 1.0 μm or less, but is melt-kneaded with the components (A) and (B) and pulverized by mechanical shearing. This method is preferable from an economic viewpoint.

  The median diameter (D50) of the component (C) before mixing with the component (A) and the component (B) is not particularly limited, but is 1 μm to 5 μm from the viewpoint of the dispersibility of the component (C). Preferably, 1.5 μm to 4 μm is more preferable. When the median diameter of the component (C) is 1 μm or more, handling becomes easy, and deterioration of the cohesiveness of the component (C) can be suppressed. (C) Since the median diameter of a component is 5 micrometers or less, it is excellent in the balance of the dispersibility and handling in a polyamide resin composition.

  Here, as defined in JIS Z8901, the median diameter (D50) is when the mass of particles larger than a certain particle size occupies 50% of the mass of all granules in the particle size distribution of the granules. The particle diameter is measured by a laser diffraction scattering method. Specifically, by the laser diffraction scattering method, the particle diameter is plotted on the horizontal axis and the frequency (mass) is plotted on the vertical axis, and the cumulative mass becomes 50% when the sum of the cumulative masses of these frequencies is 100%. It is a value measured as the particle diameter.

  Content of (C) component in a polyamide resin composition is 4-8 mass parts with respect to a total of 100 mass parts of (A) component and (B) component from a viewpoint of a flame retardance and toughness, 4 -7 parts by mass is preferable, 4-6 parts by mass is more preferable, and 4-5.5 parts by mass is particularly preferable.

[Component (D): Surfactant]
The polyamide resin composition of the present invention preferably contains a surfactant containing a fatty acid ester of at least one polyalkylene polyhydric alcohol.
Examples of the fatty acid ester of polyalkylene polyhydric alcohol include polyalkylene polyhydric alcohols such as polyethylene glycol, polypropylene glycol, polybutylene glycol, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, and serotine. Examples thereof include esters and derivatives thereof with aliphatic carboxylic acids such as acid, montanic acid, mellic acid, oleic acid, and erucic acid, and these are easily industrially available. From the viewpoint of the dispersibility of the component (C), a fatty acid ester of polyethylene glycol is preferable, and a higher fatty acid (carbon number 12 or more) ester of polyethylene glycol or a derivative thereof is more preferable.

  Suitable higher fatty acid esters of polyethylene glycol include polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene distearate, polyoxyethylene monooleate, especially polyoxyethylene monolaurate, Polyoxyethylene monostearate and polyoxyethylene monooleate are preferred.

  Suitable polyethylene glycol higher fatty acid ester derivatives include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan Trioleate is mentioned.

  It is preferable that content of (D) component in a polyamide resin composition is 0.1-1.0 mass part with respect to a total of 100 mass parts of (A) component and (B) component. By setting it as this content, in a polyamide resin composition, dispersion | distribution of (C) component becomes favorable, and it can be set as the polyamide resin composition which the hinge characteristic and the flame retardance improved more. Further, by setting the component (C) and the component (D) in the above-described content range, it has been confirmed that when a molded body is obtained, a high-quality molded body that hardly generates a scum is obtained. The mechanism for obtaining this effect is not clear, but it is presumed that component (D) is acting as a plasticizer for polyamide resin (component (A) and component (B)). Not limited to this).

  The polyamide resin composition of the present invention has a 98% sulfuric acid relative viscosity ηr (based on JIS K6920) of 2.50 to 2.83, more preferably 2.50 to 2.70, and more preferably 2.55 to 2.70. preferable. By setting the relative viscosity to 2.50 or more, the hinge characteristics of the molded product can be improved, and by setting the relative viscosity to 2.83 or less, flame retardancy can be further improved.

  In the polyamide resin composition of the present invention, in a hinge test in which a test piece having a thickness of 0.4 mm and a width of 5 mm is bent 180 degrees, the number of times until breakage (number of breaks) is 4000 times or more, and 5000 times or more. Preferably, there are 5500 times or more. The number of breaks can be measured by the method described in Examples described later.

(Other resins)
If necessary, other resins may be added to the polyamide resin composition of the present invention as long as the object of the present invention is not impaired. Examples of other resins include polytetramethylene adipamide (polyamide 46), polyhexamethylene cyclohexylamide (polyamide 6C), polyhexamethylene sebamide (polyamide 610), polyhexamethylene dodecamide (polyamide 612), Polyundecalactam (Polyamide 11), Polydodecalactam (Polyamide 12), Polyhexamethylene isophthalamide (Polyamide 6I), Polyhexamethylene terephthalamide (Polyamide 6T), Polynonanemethylene terephthalamide (Polyamide 9T), Polydodecamethylene Terephthalamide (polyamide 12T), polymetaxylylene adipamide (polyamide MXD6) and a polyamide copolymer comprising at least two different polyamide-forming components among them, Mixtures and various elastomers and the like thereof in rabbi.

[Other ingredients]
In the polyamide resin composition of the present invention, a filler that is conventionally used, for example, inorganic fibers such as glass fibers and carbon fibers, mica, talc, clay minerals, as long as the object of the present invention is not impaired as necessary. , Inorganic fillers such as alumina, silica, and apatite, aluminum hydroxide, magnesium hydroxide, zinc borate, zinc stannate, zinc hydroxystannate, ammonium polyphosphate, succinoguanamine, melamine polyphosphate, melamine sulfate, phthalate Flame retardants such as melamine acid and aluminum phosphate, pigments and colorants such as titanium white and carbon black, metal phosphites such as sodium hypophosphite, heat stabilizers represented by hindered phenol and hindered amine, Higher fatty acid metal salts, higher fatty acid amides, higher fatty acid esters, etc. , It may be added various plasticizers, and various additives such as antistatic agents.

[Production Method of Polyamide Resin Composition]
The production method of the polyamide resin composition of the present invention is not particularly limited, and (A) component, (B) component, (C) component (if necessary, (D) component, hereinafter referred to as (D) component. (Explain the case of inclusion) All may be melt-kneaded all at once, but from the viewpoint of dispersibility of the melamine cyanurate flame retardant of component (C), a part of component (C) is melted with all remaining components. In addition to kneading, it may be further melt kneaded. Further, a master batch containing the components (A) to (D) may be prepared in advance and melt kneaded using this master batch.

  The shape of the (A) component and the (B) component polyamide resin is not particularly limited, but is preferably a pellet. In this case, from the viewpoint of simplifying the equipment, the (D) component surfactant is spread on the surface of the (A) component and (B) component polyamide resin pellets, and then the (C) melamine component. You may melt-knead | mix knead | mixing after making the blend thing which spread the cyanurate type flame retardant. Even in this configuration, from the viewpoint of dispersibility, a part of the component (C) may not be spread, and all the remaining components may be melt-kneaded and further melt-kneaded.

  In the method for producing the polyamide resin composition of the present invention, the method of melt kneading is not particularly limited, but at least one machine is used when mixing the component (A), the component (B), the component (C) and the component (D). It is preferable to use a raw material supply apparatus for supplying to an extruder and melt-kneading. Separate raw material supply devices may be used to supply each component to the extruder, or a single raw material supply device may be used.

  The extruder is not particularly limited, but a twin screw extruder is preferable. Specific examples of the twin screw extruder include the ZSK series manufactured by COPERIION, the TEM series manufactured by Toshiba Machine Co., Ltd., the TEX series manufactured by Nippon Steel Works, Ltd., and the like. / D (screw effective length / screw outer diameter) is preferably in the range of 20 or more and 60 or less, and more preferably 30 or more and 50 or less.

  The method for supplying the raw material to the twin screw extruder is not particularly limited. The raw material supply device is not particularly limited, and a single screw feeder, a twin screw feeder, a table feeder, a rotary feeder, a liquid supply pump, or the like can be used. Of these, the loss-in-weight screw feeder is preferable because it has less fluctuation error in raw material supply. In addition, when a plurality of types of raw materials are input to one raw material supply apparatus, at least two types of raw materials to be input may be mixed after being mixed with a mixer, a cone blender, or the like.

  The temperature at the time of kneading and melting is preferably 5 to 30 ° C. higher than the melting point of the component (A), more preferably 5 to 20 ° C. from the viewpoint of productivity and suppression of thermal deterioration. .

[Molded body]
Since the molded body formed by molding the polyamide resin composition of the present invention has characteristics that suppress high variations in flame retardancy, hinge characteristics, and hinge characteristics, such as sockets, switches, cases, covers, etc. It is suitable as an injection molded body used as an electronic component, an automotive interior / exterior component, an automotive electrical component, etc., and a pellet as a molding material of these injection molded bodies. In particular, it is public for connector parts and clips having hinge portions. In particular, high flame retardance and small variation in hinge characteristics due to thin walls can contribute to recent demands for thinner molded products, etc., and small variations in hinge properties can reduce the defective rate of molded products. Because it can contribute, the industrial meaning is very large.

The present invention will be described in further detail using examples and comparative examples.
(Material property evaluation method)
The physical property evaluation described in the following examples and comparative examples was performed as follows.

<Sulfuric acid relative viscosity ηr>
The sulfuric acid relative viscosity ηr (25 ° C., 1 g / 100 ml) of the component (A), the component (B) and the polyamide resin composition was measured according to JIS K6920.

<Melting point>
The melting point of the component (A) was measured using a differential calorimeter DSC-7 manufactured by PerkinElmer. The temperature increase and temperature decrease conditions were each 20 ° C./min. About 10 mg of the sample was heated from room temperature, the endothermic peak temperature (Tm1) was observed, and then held at a temperature 20 to 50 ° C. higher than Tm1 for 3 minutes. Next, after cooling the sample to room temperature, the temperature was raised again and an endothermic peak was observed. The temperature indicated by the peak top was taken as the melting point.

<Medium diameter>
The median diameter of component (C) was measured using a laser diffraction particle size distribution analyzer SALD-7000 manufactured by Shimadzu Corporation. A sample dispersed in pure water was used as a measurement sample, and measurement was performed using a flow cell. The particle diameter is plotted on the horizontal axis, and the frequency (mass) is plotted on the vertical axis. When the sum of the cumulative masses of these frequencies is 100%, the particle diameter at which the cumulative mass becomes 50% is defined as the median diameter (D50). did.

(Preparation of each component)
[(A) component: polyamide 66/6 resin, polyamide 66 resin]
Component (a-1): Polyamide 66/6 resin Necessary for producing 18.8 kg of copolyamide 66/6 containing 90% by mass of a binding unit corresponding to polyamide 66 and 10% by mass of a binding unit corresponding to polyamide 6. An aqueous monomer solution of 39.2 kg of 50% by mass of AH salt (an equimolar salt of adipic acid and hexamethylenediamine) and 1.9 kg of ε-caprolactam were charged into an 80 liter autoclave and stirred well. After sufficiently replacing with nitrogen, the temperature was raised from room temperature to 220 ° C. At this time, the pressure in the autoclave was 1.8 MPa in terms of gauge pressure, but heating was continued for 1 hour while removing water out of the system so that the pressure did not exceed 1.8 MPa. After that, when the internal temperature reaches 270 ° C., the pressure is reduced to atmospheric pressure over 60 minutes while removing water out of the system, then the heating is stopped, the polymer is discharged in a strand form from the lower nozzle, and the water-cooled cutter Were cut into cylindrical pellets having a diameter of 3 mmφ × 3 mm in length to obtain granules of copolymerized polyamide 66/6 resin (mass ratio of copolymerized components 66: 6 = 90: 10 ηr: 2.63 melting point 245 ° C.) .

Component (a-2): Polyamide 66/6 resin When the internal temperature of the autoclave reaches 270 ° C., except that the time for reducing the pressure to atmospheric pressure is 45 minutes while removing water out of the system (a -1) (mass ratio of copolymerizable component 66: 6 = 90: 10 ηr: 2.2 melting point 245 ° C.).

Component (a-3): Polyamide 66/6 resin When the internal temperature of the autoclave reaches 270 ° C., except that the time for reducing the pressure to atmospheric pressure is 75 minutes while removing water out of the system (a -1) (mass ratio of copolymerizable component 66: 6 = 90: 10 ηr: 2.9 melting point 245 ° C.).

(A-4) Component: Polyamide 66 resin 15 kg of an aqueous solution containing 50% by mass of a monomer mixture containing equimolar amounts of hexamethylenediamine and adipic acid was prepared. Next, the monomer aqueous solution was charged into a 40 L autoclave having a stirring device and having a nozzle extracted at the bottom, and the monomer aqueous solution was sufficiently stirred at 50 ° C. After sufficiently replacing the inside of the autoclave with nitrogen, the temperature inside the autoclave was increased from 50 ° C. to about 270 ° C. while the monomer aqueous solution was stirred, and polymerization was performed. At that time, the pressure in the autoclave was about 1.8 MPa in terms of gauge pressure, but water was discharged from the system as needed so that the pressure did not exceed 1.8 MPa. The polymerization time was adjusted so that the polyamide 66 resin had a relative sulfuric acid relative viscosity of about 2.73.
After completion of the polymerization in the autoclave, the polyamide 66 resin was discharged in a strand form from the lower nozzle, and water cooling and cutting were performed to obtain a pellet-like polyamide 66 resin (ηr: 2.73).

[(B) component: polyamide 6 resin]
(B-1): Polyamide 6 SF1013A, Ube Industries, Ltd. Sulfuric acid relative viscosity 2.6
(B-2): Polyamide 6 Ube Industries 1010X1 Sulfuric acid relative viscosity 2.0
(B-3): Polyamide 6 Ube Industries 1030B Sulfuric acid relative viscosity 4.4

[(C) component: melamine cyanurate flame retardant]
(C-1): Melamine cyanurate Middle diameter (D50): 2.6 μm
(C-2): Melamine cyanurate Medium diameter (D50): 6.5 μm

[Component (D): Surfactant]
(D-1) PEM: Polyoxyethylene monolaurate Emanon (registered trademark) 1112 manufactured by Kao Corporation

[Example 1]
(A-1) Polyamide 66/6 copolymer, (b-1) Polyamide 6 resin, (c-1) Melamine cyanurate, Loss-in-weight feeder (LWF-D5 manufactured by K-TRON) It supplied to the 1st supply port of the twin-screw extruder (Toshiba machine Co., Ltd. product TEM35BS, a biaxial same direction screw rotation type, L / D = 47.6). Extrusion was performed at a barrel temperature of 260 ° C., a discharge rate of 30 kg / hr, and a screw rotation speed of 150 rpm. The screw of the extruder was provided with two kneading blocks. The polymer was discharged in a strand form from the nozzle at the tip of the extruder, water-cooled and cut to obtain polyamide resin composition pellets.

[Examples 2 to 9, Comparative Examples 1 to 7]
Polyamide resin composition pellets of Examples 2 to 9 and Comparative Examples 1 to 7 were produced in the same manner as Example 1 except that the composition of each component was as described in Table 1. In addition, about Example 9, barrel temperature was implemented at 270 degreeC.

(Evaluation of polyamide resin composition)
The polyamide resin composition pellets of each example and comparative example were evaluated. Table 1 shows the evaluation items and the results. The evaluation method for each evaluation item was as follows.
<Measurement of sulfuric acid relative viscosity>
1.00 g of the resin composition cut out from the polyamide resin composition pellets produced in each Example and Comparative Example was dissolved in 100 g of 98% concentrated sulfuric acid and measured at 25 ° C. according to JIS K6920.

<Mass ratio of polyamide 66 units / polyamide 6 units in resin composition>
The pellet was dissolved in deuterated formic acid, and ¹³ C-NMR was measured. At this time, the molar ratio of polyamide 66 and polyamide 6 was calculated from the peak area ratio of the polyamide 66 and the carbon derived from polyamide 6, and the molecular weight was multiplied to obtain the mass ratio.

<Average particle diameter of component (C)>
Sections perpendicular to the long sides of the cylindrical pellets of the resin compositions obtained in the examples and comparative examples were taken out, and the sections were observed at a magnification of 3000 times using a scanning electron microscope. The average particle size was measured using image analysis software (Image-Pro Plus 5.0J, manufactured by Media Cybernetics).

<Tensile elongation>
The polyamide resin composition pellets are set using an injection molding machine (PS40E manufactured by Nissei Resin Co., Ltd.) at a cylinder temperature of 270 ° C. and a mold temperature of 80 ° C., and injection is performed under injection molding conditions of 25 seconds for injection and 10 seconds for cooling. Molded to obtain a 4 mm thick ISO test piece. Using the obtained ISO test piece, the tensile elongation was measured according to ISO 527-1.

<Hinge characteristics, hinge standard deviation, low temperature hinge>
The polyamide resin composition pellets produced in each example and comparative example are shown in FIGS. 1 and 2 using an injection molding machine (manufactured by Nissei Kogyo Co., Ltd .: PS40E cylinder temperature 270 ° C., mold temperature 80 ° C.). The hinge molded body 1 was molded. FIG. 1 is a top view of the hinge molded product 1, and FIG. 2 is a side view of the hinge molded product 1. The hinge molded product 1 includes a hinge portion 22. About the produced hinge molded product 1 of each example, the hinge part 22 was bent to almost 180 degrees using an automatic repeated hinge tester in an atmosphere of 23 ° C. and 50% RH, and returned to the original position (0 °). The returning operation was repeated at a rate of 33 times / minute, and the number of bending times at which the material was bent and broken was measured. In the hinge test, 15 pieces were measured, and the average value of the 15 pieces was used as a hinge characteristic value, and the standard deviation was used as an index of variation. A hinge characteristic value that did not break even 4000 times was regarded as acceptable. The standard deviation was evaluated according to the following criteria.
A: Less than 2000 B: 2000 or more to less than 4000 C: 4000 or more As a low-temperature hinge characteristic, after leaving the hinge molded body 1 in a 0 ° C. environment for 2 hours, the test piece was bent 180 ° by hand, and 20 pieces Of these, the number of fractured specimens was counted and evaluated as follows.
A: Number of breaks 0 to 5 B: Number of breaks 6 to 10 C: Number of breaks 11 or more

<Flame retardance>
Using the resin composition pellets produced in the examples and comparative examples, supplying them to a screw in-line injection molding machine set at 270 ° C., and a test for measuring UL-94 vertical combustion test at a mold temperature of 80 ° C. Pieces were injection molded (thickness: 0.35 mm and 0.71 mm). Using the five test pieces having different thicknesses formed in this way, flame retardancy was evaluated based on the UL-94 vertical combustion test, and flame retardancy V-0, V-1, V-2, HB The judgment of was carried out.

  As shown in Table 1, according to the present invention, flame retardancy and hinge characteristics are excellent, and variations in hinge characteristics can also be improved.

  Since the polyamide resin composition of the present invention has high flame retardancy, it is useful as industrial materials for various machine industry parts and electrical / electronic parts, particularly connectors and clips.

1 Hinge molding 22 Hinge part

Claims (10)

  A polyamide resin composition comprising (A) a polyamide 66/6 copolymer and / or a polyamide 66 resin, (B) a polyamide 6 resin and (C) a melamine cyanurate flame retardant, wherein the component (A) and the above (B) 4-100 mass parts of (C) component is included with respect to 100 mass parts of total components, and the mass ratio of polyamide 66 units / polyamide 6 units in the polyamide resin composition is 88 / 12-73 / 27. The polyamide resin composition has a 98% sulfuric acid relative viscosity ηr (according to JIS K6920) of 2.50 to 2.83, and the polyamide resin composition has an average particle size of component (C) of 1.0 μm or less. Resin composition.   0.1 to 1.0 mass of a surfactant further comprising (D) a fatty acid ester of at least one polyalkylene polyhydric alcohol with respect to a total of 100 mass parts of the component (A) and the component (B). The polyamide resin composition according to claim 1 comprising parts.   3. The polyamide resin composition according to claim 1, wherein the polyamide 66/6 copolymer of the component (A) is composed of 50 to 95 mass% of polyamide 66 units and 5 to 50 mass% of polyamide 6 units.   The polyamide resin composition according to any one of claims 1 to 3, wherein the component (A) has a 98% sulfuric acid relative viscosity ηr (based on JIS K6920) of 2.3 to 2.9.   The polyamide resin composition according to any one of claims 1 to 4, wherein the component (B) has a 98% sulfuric acid relative viscosity ηr (based on JIS K6920) of 2.1 to 2.7.   The polyamide resin composition according to claim 1, wherein the polyamide resin composition has a 98% sulfuric acid relative viscosity ηr (based on JIS K6920) of 2.50 to 2.70.   The component (D) is polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene distearate, polyoxyethylene monooleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate The polyamide resin composition according to any one of claims 2 to 6, which is at least one selected from the group consisting of polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, and polyoxyethylene sorbitan trioleate. .   The molded object formed by shape | molding the polyamide resin composition of any one of Claims 1-7.   The molded body according to claim 8, which is a connector part including a hinge part.   The molded article according to claim 8, which is a clip.