JP2013060580A - Conductive polyamide resin composition, and molding thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide resin composition excellent in mechanical properties, heat resistance and conductivity, and excellent in moldability.SOLUTION: The polyamide resin composition contains 100 pts.mass of a polyamide composed of a dicarboxylic acid component and a diamine component, and 5 to 50 pts.mass of a conductivity imparting agent, wherein the main component of the dicarboxylic acid component constituting the polyamide is terephthalic acid, and the main component of the diamine component is at least one selected from the group consisting of 1,8-octanediamine, 1,10-decanediamine and 1,12-dodecanediamine; and the degree of supercooling of the polyamide measured using a differential scanning calorimeter is ≤40°C.

Description

  The present invention relates to a conductive polyamide resin composition.

  Semi-aromatic polyamides typified by polyamide 6T and polyamide 9T are excellent in heat resistance and mechanical properties, and thus are used in a wide range of fields such as electric / electronics and automobiles. In recent years, among these fields, in the use of separators for fuel cells and the like, it has been studied to disperse and use conductive materials (for example, Patent Document 1).

JP 2005-222937 A

  However, polyamide 9T used in the resin composition of Patent Document 1 is copolymerized with 2-methyl-1,8-octanediamine in addition to 1,9-nonanediamine. Therefore, there is a problem that the crystallization time in the mold becomes long, that is, the molding cycle becomes long.

  An object of the present invention is to provide a polyamide resin composition excellent in moldability in addition to excellent mechanical properties, heat resistance, and conductivity.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems.
That is, the gist of the present invention is as follows.
(1) A conductive polyamide resin composition containing 100 parts by mass of a polyamide composed of a dicarboxylic acid component and a diamine component and 5 to 50 parts by mass of a conductivity-imparting agent, the main component of the dicarboxylic acid component constituting the polyamide Is terephthalic acid, and the main component of the diamine component is at least one selected from the group consisting of 1,8-octanediamine, 1,10-decanediamine and 1,12-dodecanediamine, and the differential scanning of the polyamide A conductive polyamide resin composition, wherein the degree of supercooling measured using a calorimeter is 40 ° C. or less.
(2) The conductive polyamide resin composition according to (1), wherein the polyamide is end-capped with a monocarboxylic acid having a molecular weight of 140 or more.
(3) The conductive polyamide resin composition as described in (1) or (2), wherein the diamine component constituting the polyamide is 1,10-decanediamine.
(4) The conductive polyamide resin composition according to any one of (1) to (3), wherein the triamine unit is 0.3 mol% or less relative to the diamine unit in the polyamide.
(5) The conductive polyamide resin according to any one of (1) to (4), wherein the conductivity imparting agent is at least one selected from the group consisting of carbon black, carbon fiber, and metal fiber. Composition.
(6) A molded article obtained by molding the conductive polyamide resin composition according to any one of (1) to (5).

  According to the present invention, it is possible to provide a polyamide resin composition that is excellent in moldability in addition to the excellent mechanical properties, heat resistance, and conductivity of a conventional conductive semi-aromatic polyamide.

Hereinafter, the present invention will be described in detail.
The polyamide used in the present invention is composed of a dicarboxylic acid component and a diamine component. In the present invention, it is necessary to use a dicarboxylic acid component and a diamine component having a specific chemical structure from the viewpoint of high crystallinity.

  The dicarboxylic acid component constituting the polyamide needs to use terephthalic acid as a main component. Since terephthalic acid has a high chemical structure symmetry among aromatic dicarboxylic acids, a polyamide having high crystallinity and good moldability can be obtained.

  The diamine component constituting the polyamide needs to use one or more selected from the group of 1,8-octanediamine, 1,10-decanediamine and 1,12-dodecanediamine as a main component. 1,8-Octanediamine, 1,10-decanediamine, and 1,12-dodecanediamine are linear aliphatic diamines and have high chemical structure symmetry. A polyamide having good moldability and good moldability can be obtained.

  The number of carbon atoms of the diamine as the main component of the diamine component needs to be an even number. In general, in polyamide, a so-called even-odd effect is developed, and a more stable crystal structure is obtained when the number of carbon atoms of the monomer unit of the diamine component used is an even number than when the number of carbon atoms is an odd number. This is because crystallinity is improved.

  The carbon number of the diamine as the main component of the diamine component needs to be 8, 10, 12. When the number of carbon atoms of the diamine is less than 8, it is not preferable because the obtained polyamide has a melting point exceeding 340 ° C. and exceeding the decomposition temperature of the amide bond. On the other hand, when the diamine has more than 12 carbon atoms, the polyamide obtained is insufficient in heat resistance, which is not preferable. Note that due to the even-odd effect, the polyamide having 9 or 11 carbon atoms in the diamine has lower crystallinity than the polyamide having 8 or 10 or 12 carbon atoms in the diamine.

  The polyamide used in the present invention includes a dicarboxylic acid component other than the terephthalic acid component as the main component and / or other diamine components of a type other than the linear aliphatic diamine component having 8, 10 or 12 carbon atoms. (Hereinafter may be abbreviated as “copolymerization component”) may be copolymerized. The copolymerization component is preferably 5 mol% or less with respect to the total number of moles of the raw material monomers, and more preferably substantially free of the copolymerization component. Crystallinity can be improved by making a copolymerization component into 5 mol% or less.

  Other dicarboxylic acid components include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid and other aliphatic dicarboxylic acids, cyclohexane Examples include alicyclic dicarboxylic acids such as dicarboxylic acids, and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and naphthalenedicarboxylic acid.

  Other diamine components include 1,2-ethanediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, , 8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, aliphatic diamine such as 1,12-dodecanediamine, alicyclic diamine such as cyclohexanediamine, xylylenediamine Aromatic diamines such as In addition, any of 1,8-octanediamine, 1,10-decanediamine, and 1,12-octanediamine listed above is an essential diamine component for the polyamide of the present invention. When any one of 1,8-octanediamine, 1,10-decanediamine, and 1,12-dodecanediamine is used as an essential diamine component, the other diamine components are used as copolymerization components. For example, when 1,8-octanediamine is used as an essential diamine component, 1,10-decanediamine and 1,12-dodecanediamine are used as copolymerization components.

  If necessary, the polyamide may be copolymerized with lactams such as caprolactam and laurolactam, and ω-aminocarboxylic acids such as aminocaproic acid and 11-aminoundecanoic acid.

  The weight average molecular weight of the polyamide is preferably 15000 to 50000, more preferably 20000 to 50000, and further preferably 26000 to 50000. By setting the weight average molecular weight of the polyamide to 15000 to 50000, the mechanical properties can be improved while maintaining the fluidity at the time of injection molding.

  The relative viscosity of the polyamide is not particularly limited, and may be appropriately set depending on the purpose. For example, in order to obtain a polyamide that can be easily molded, the relative viscosity is preferably 2.0 or more.

  The polyamide used in the present invention preferably has a sufficiently reduced amount of triamine. Polyamide tends to have a triamine structure as a by-product due to a condensation reaction between diamines during polymerization. When the amount of triamine is large, a crosslinked structure is formed in the molecular chain, and the crosslinked structure restricts the movement and arrangement of the molecular chain, so that the crystallinity is lowered. Further, when the amount of triamine is large, a large amount of gel is generated, so that it may be present as fish eyes or irregularities on the surface of the obtained molded body, which may cause a deterioration of the surface appearance. Therefore, the triamine unit contained in the polyamide is preferably 0.3 mol% or less of the diamine unit, more preferably 0.15 mol% or less, and further preferably 0.12 mol% or less. Preferably, it is 0.10 mol% or less. When the triamine structure in the polyamide exceeds 0.3 mol% of the diamine unit, the crystallinity may be lowered, the surface smoothness of the molded product obtained by the generation of gel may be impaired, and the color tone may be lowered. is there.

  In order to make the triamine unit 0.3 mol% or less of the diamine unit, when the salt is formed from the terephthalic acid component and the diamine component, the amount of water or organic solvent added is 100 parts by mass based on the total amount of raw material monomers. The amount is preferably 5 parts by mass or less, more preferably less than 0.5 parts by mass, and still more preferably not used at all.

  In general, in order to allow the heat polymerization reaction of polyamide to proceed uniformly, a method is used in which raw materials are mixed in the presence of water and heated to advance the dehydration reaction. However, in such a method, when the total amount of water and the organic solvent during polymerization exceeds 5 parts by mass with respect to 100 parts by mass of the raw material monomers, an increase in the degree of polymerization may be suppressed. is there. In that case, the residence time in the polymerization apparatus in a state where there are many amine ends becomes longer, and the amount of triamine by-produced by the condensation reaction between diamines increases. As a result, a part of the polyamide takes a crosslinked structure, and gelation is promoted or the color tone is lowered. Gelation causes a decrease in the crystallinity of the polyamide and delays the crystallization rate. And in the semi-aromatic polyamide like this invention, the production | generation of a triamine is more remarkable than an aliphatic polyamide. Therefore, as in the present invention, in order to obtain a polyamide in which the triamine unit is 0.3 mol% or less of the diamine unit, the amount of water or an organic solvent added is 5 masses per 100 mass parts of the raw material monomers in total. Part or less, and it is more preferable that water is not substantially added.

  The polyamide resin composition of the present invention has a high crystallization rate and high moldability. The crystallization speed in the present invention can be determined by using the degree of supercooling measured using a differential scanning calorimeter (DSC) as an index. In the present invention, the degree of supercooling of the polyamide to be used needs to be 40 ° C. or less, and preferably 35 ° C. or less. When the degree of supercooling of the polyamide used exceeds 40 ° C, the crystallinity cannot be sufficiently increased, the molding cycle cannot be shortened, and it is difficult to release from the mold, so that continuous productivity during molding is achieved. May decrease.

  The polyamide used in the present invention can be produced by a heat polymerization method or a solution polymerization method that has been conventionally known as a method for producing a polyamide. Of these, the heat polymerization method is preferably used because it is industrially advantageous.

  Examples of the heat polymerization method include a method comprising a step (i) of obtaining a reactant from a monomer and a step (ii) of polymerizing the reactant. In the present invention, in order to obtain a polyamide in which the triamine unit is 0.3 mol% or less of the diamine unit, the step of step (i) is performed under the condition that the water and solvent in the polymerization system are low, that is, dicarboxylic acid and diamine. It is preferable to carry out in the presence of water and / or an organic solvent in which the total amount of water and the organic solvent is 5 parts by mass or less with respect to 100 parts by mass in total.

  As the step (i), for example, the dicarboxylic acid powder is heated in advance to a temperature not lower than the melting point of the diamine and not higher than the melting point of the dicarboxylic acid, and at a temperature not lower than the melting point of the diamine and not higher than the melting point of the dicarboxylic acid. The method of adding diamine to the dicarboxylic acid powder without substantially containing water so as to keep the water content. Alternatively, as another method, a suspension of a molten diamine and solid terephthalic acid is stirred and mixed to obtain a mixed solution, and then at a temperature lower than the melting point of the finally produced polyamide, terephthalic acid and diamine And a method of obtaining a mixture of a salt and a low polymer by performing a production of a salt by a reaction with the salt and a production reaction of a low polymer by polymerization of the salt. In this case, crushing may be performed while the reaction is performed, or crushing may be performed after the reaction is once taken out. As the step (i), the former method in which the shape of the reactant is easily controlled is preferable.

As the step (ii), for example, the reaction product obtained in the step (i) is solid-phase polymerized at a temperature lower than the melting point of the finally produced polyamide to increase the molecular weight to a predetermined molecular weight to obtain a polyamide. A method is mentioned. The solid phase polymerization is preferably performed in a stream of inert gas such as nitrogen at a polymerization temperature of 180 to 270 ° C. and a reaction time of 0.5 to 10 hours.

  In the production of polyamide, a polymerization catalyst can be used to increase the efficiency of polymerization, and a terminal blocking agent can be used to adjust the degree of polymerization, suppress thermal decomposition and coloring.

  Examples of the polymerization catalyst include phosphoric acid, phosphorous acid, hypophosphorous acid or salts thereof. The addition amount of the polymerization catalyst is usually 2 mol% or less based on the total mol of dicarboxylic acid and diamine. It is preferable.

  Examples of the end-capping agent include monocarboxylic acids such as acetic acid, lauric acid, stearic acid, and benzoic acid, and monoamines such as octylamine, cyclohexylamine, and aniline. Among these, monocarboxylic acids having a molecular weight of 140 or more such as lauric acid and stearic acid are preferable. By using a monocarboxylic acid having a molecular weight of 140 or more, the fluidity during molding can be improved without lowering the melting point of the polyamide. As the addition amount of the terminal blocking agent, it is usually preferable to use it at 5 mol% or less based on the total of the dicarboxylic acid component and the diamine component.

  The conductivity-imparting agent used in the present invention is not particularly limited as long as it can be added to polyamide to impart conductivity. Examples of the conductivity imparting agent include carbon black, carbon fiber, and metal fiber. Among these, carbon black and carbon fiber are preferable.

Examples of carbon black include acetylene black obtained by incomplete combustion of acetylene gas, ketjen black obtained by furnace type incomplete combustion using crude oil as a raw material, oil black, naphthalene black, thermal black, channel black, roll Black and disk black are listed. Of these, ketjen black is preferable. The average particle size of the carbon black is preferably 500 nm or less, more preferably 5 to 100 nm, and even more preferably 10 to 70 nm because the volume resistivity can be lowered with a smaller amount. . Surface area of the carbon black is preferably at 10 m ² / g or more, more preferably 300 meters ² / g or more, further preferably 500 to 1500 ² / g. The DBP (dibutyl phthalate) oil absorption of carbon black is preferably 50 mL / 100 g or more, more preferably 100 mL / 100 g, and further preferably 300 mL / 100 g or more. The ash content of carbon black is preferably 0.5% by weight or less, and more preferably 0.3% by weight or less. The average particle diameter is a value measured with an electron microscope, the surface area is a value measured according to JIS K6217, the DBP oil absorption is a value measured according to ASTM D2414, and the ash content is a value measured according to JIS K6218.

  Examples of the carbon fiber include pitch-based carbon fiber and PAN-based carbon fiber. Among them, PAN-based carbon fiber is preferable because bending strength and bending elastic modulus are improved. The average fiber length of the carbon fibers is preferably 0.1 to 20 mm, more preferably 1 to 10 mm, and further preferably 5 to 8 mm before being melt-kneaded. Moreover, it is preferable that the fiber diameter of carbon fiber is 5-15 micrometers.

  Examples of the metal fibers include copper, iron, nickel, gold, silver, titanium, aluminum, stainless steel, and brass fibers. Among these, stainless steel fibers are preferable from the viewpoint of corrosion resistance. The average fiber length of the metal fibers is preferably 0.1 to 15 mm, and more preferably 0.1 to 12 mm, before the melt kneading. Moreover, it is preferable that the fiber diameter of a metal fiber is 3-30 micrometers, It is more preferable that it is 3-20 micrometers, It is further more preferable that it is 5-15 micrometers.

The content of the conductivity imparting agent needs to be 5 to 50 parts by mass with respect to 100 parts by mass of the polyamide, preferably 5 to 45 parts by mass, and more preferably 5 to 40 parts by mass. Preferably, it is 1-30 mass parts. When the content of the conductivity-imparting agent is less than 5 parts by mass, the volume resistivity value is larger than 1.0 × 10 ⁸ Ω · cm, and sufficient conductivity cannot be obtained. In addition, since it has low electrical conductivity, it is charged with static electricity, and dust and dust may adhere to it, causing problems in precision products. On the other hand, when the content of the conductivity imparting agent exceeds 50 parts by mass, the fluidity is lowered, and as a result, the moldability is lowered, which is not preferable. Moreover, the strand of a resin composition cannot be produced and it may become impossible to obtain a pellet.

  The method for adding the conductivity imparting agent is not particularly limited, but melt kneading using a biaxial kneader is preferably used. The kneading temperature needs to be not less than the melting point of the polyamide, and is preferably less than (melting point + 100 ° C.). If the kneading temperature is lower than the melting point, the kneader is overloaded, and problems such as vent-up may occur. If the kneading temperature is too high, the polyamide may be decomposed or yellowed. Although the collection method of the obtained polyamide resin composition is not particularly limited, it is preferable to produce a strand and pelletize it in consideration of subsequent molding.

  The polyamide resin composition of the present invention may contain a fibrous reinforcing material that does not correspond to the conductivity-imparting material. Examples of such fibrous reinforcing materials include glass fiber, boron fiber, asbestos fiber, polyvinyl alcohol fiber, polyester fiber, acrylic fiber, wholly aromatic polyamide fiber, polybenzoxazole fiber, polytetrafluoroethylene fiber, and kenaf fiber. , Bamboo fiber, hemp fiber, bagasse fiber, high strength polyethylene fiber, alumina fiber, silicon carbide fiber, potassium titanate fiber, ceramic fiber, and basalt fiber.

  You may add additives, such as another filler and a stabilizer, to the polyamide resin composition of this invention as needed. The additive is added, for example, at the time of polymerizing the polyamide or melt kneading. Examples of additives include fillers such as talc, swellable clay minerals, silica, alumina, and glass beads, pigments such as titanium oxide, antioxidants, flame retardants, and flame retardant aids.

  Examples of the molding method of the polyamide resin composition include an injection molding method, an extrusion molding method, and a blow molding method. Among these, the injection molding method can be preferably used because the mechanical properties and moldability can be sufficiently improved. Although it does not specifically limit as an injection molding machine, For example, a screw in-line type injection molding machine and a plunger type injection molding machine are mentioned. The polyamide resin composition heated and melted in the cylinder of the injection molding machine is weighed for each shot, injected into the mold in a molten state, cooled to a predetermined shape and solidified, and then as a molded body from the mold. It is taken out. The resin temperature at the time of injection molding must be equal to or higher than the melting point of the polyamide resin composition, and is preferably less than (melting point + 100 ° C.). When the polyamide resin composition is heated and melted, it is preferable to use a sufficiently dried polyamide resin composition. If the water content is large, the resin foams in the cylinder of the injection molding machine, and it may be difficult to obtain an optimal molded body. The moisture content of the polyamide resin composition used for injection molding is preferably less than 0.3% by mass, and more preferably less than 0.1% by mass.

  Since the polyamide resin composition of the present invention is produced mainly using a polyamide having a degree of supercooling measured by DSC of 40 ° C. or less, the crystallization speed is fast, especially during processing of a molded body, particularly injection molding. The molding cycle can be shortened and the molding cost can be reduced.

  The conductive polyamide resin composition of the present invention is excellent in electrical conductivity in addition to mechanical properties, heat resistance, and moldability. Therefore, a separator for a fuel cell, an LED reflector, an LED housing, a connector, a switch, a sensor, It can be suitably used for electrical and electronic parts such as sockets, capacitors, jacks, fuse holders, relays, coil bobbins, resistors, ICs, and cell phone cases.

  In addition, the conductive polyamide resin composition of the present invention can also be used in a wide range of applications such as automobile parts, electrical and electronic parts, miscellaneous goods, and civil engineering and building supplies.

  Auto parts include muffler cover, intake duct, rear spoiler, wheel cover, wheel cap, cowl vent grill, air outlet louver, air scoop, hood bulge, fender, back door, shift lever housing, window regulator, door lock, Interior and exterior parts such as door handles, outside door mirror stays, engine cover, air intake manifold, throttle body, air intake pipe, radiator tank, radiator support, radiator hose, radiator grill, timing belt cover, water pump renlet, water pump Engine peripheral parts such as outlets, cooling fans, fan shrouds, engine mounts, propeller shafts, stabilizer bars Mechanical parts such as cage rod, accelerator pedal, pedal module, seal ring, bearing retainer, gear, driven gear, electric power steering gear, oil pan, oil filter housing, oil filter cap, oil level gauge, fuel tank, fuel tube, Fuel cut-off valves, canisters, fuel delivery pipes, fuel filler necks, fuel sender modules, fuel pipe fittings and other fuel / piping system parts, wire harnesses, relay blocks, sensor housings, encapsulations, ignition coils, distributors , Thermostat housing, quick connector, lamp reflector, lamp housing, lamp extension, lamp socket, Electrical system parts of the bobbin, such as for emissions and the like.

  Electrical and electronic parts include connectors, LED reflectors, switches, sensors, sockets, capacitors, jacks, fuse holders, relays, coil bobbins, resistors, ICs, LED housings, various cases, copier gears, various insulators, etc. Can be mentioned.

  The miscellaneous goods include resin screws, clock frames, fasteners, price tag tags, cable ties, casters and the like.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

1. Measurement Method (1) Relative Viscosity of Polyamide Measured at a concentration of 1 g / dL and 25 ° C. using 96 mass% sulfuric acid as a solvent.

(2) Weight average molecular weight of polyamide After performing GPC analysis on a sample solution adjusted under the following conditions using a gel permeation chromatography apparatus manufactured by Tosoh Corporation, a calibration prepared using polymethyl methacrylate (manufactured by Polymer Laboratories) as a standard sample The weight average molecular weight was determined using a line.
<Sample preparation>
2 ml of hexafluoroisopropanol containing 10 mM sodium trifluoroacetate was added to 5 mg of polyamide and dissolved, followed by filtration with a disk filter.
<Conditions>
-Detector: Differential refractive index detector RI-8010 (manufactured by Tosoh Corporation)
Eluent: Hexafluoroisopropanol containing 10 mM sodium trifluoroacetate Flow rate: 0.4 ml / min Temperature: 40 ° C

(3) Decreasing crystallization temperature, melting point, and degree of supercooling of polyamide Using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer, Inc., the temperature was raised to 350 ° C. at a rate of temperature increase of 20 ° C./min. The temperature which gives the top of the exothermic peak when the temperature is lowered to 25 ° C. at a temperature lowering rate of 20 ° C./min is maintained at a temperature lowering crystallization temperature (Tcc). The top of the endothermic peak when the temperature was measured in minutes was taken as the melting point (Tm). The difference between the melting point and the cooling crystallization temperature (Tm-Tcc) was defined as the degree of supercooling.

(4) Determination of triamine in polyamide 3 mL of 47% hydrobromic acid was added to 10 mg of polyamide, heated at 130 ° C. for 20 hours, evaporated to dryness, and further dried under reduced pressure at 80 ° C. for 2 hours. To this, 2 mL of pyridine and 1 mL of N, O-bis (trimethylsilyl) trifluoroacetamide were added and heated at 90 ° C. for 30 minutes. After cooling, the solution filtered with a membrane filter was analyzed with a gas chromatography apparatus equipped with a mass spectrometer. Using a calibration curve obtained by separately measuring diamine and triamine as standard materials, diamine and triamine in the polyamide were quantified, and the molar ratio of triamine to diamine was calculated. As a triamine standard substance, a triamine compound obtained by reacting diamine with heating and stirring at 240 ° C. for 3 hours in an autoclave using palladium oxide as a catalyst was used.

(5) Melt flow rate (MFR)
Using the polyamide resin composition, measurement was performed at 340 ° C. and a load of 1.2 kgf in accordance with JIS K7210. Practically, 0.1 to 50 g / 10 min is preferable, and 1 to 40 g / 10 min is more preferable.

(6) Volume Specific Resistance Value After sufficiently drying the polyamide resin composition, injection molding was performed using an injection molding machine (EC100 manufactured by Toshiba Machine Co., Ltd.) to produce a 127 mm × 12.7 mm × 10 mm molded piece. The cylinder temperature was (melting point + 25 ° C.), the mold temperature was (melting point−185 ° C.), the injection pressure was 100 MPa, the injection time was 10 seconds, and the removal time was 5 seconds.
The obtained molded piece was measured under a voltage of 500 V according to ASTM D257 using a mega ohm meter manufactured by Toa Denpa.

(7) Flexural strength, flexural modulus Measured according to ASTM D790 using the molded piece obtained in (6).

(8) Molding cycle When the molded body was molded in (6), the shortest time that could be easily taken out without deforming the molded body with the protruding pin was measured. Here, the molding cycle refers to the time from the start of the injection of the first shot of the molded body to the start of the injection of the second shot of the molded body when continuously molded under the same injection conditions. That is, it refers to the time required to mold one molded body (total of injection time + cooling time + removal time). Practically, it is preferably 45 seconds or shorter, and more preferably 30 seconds or shorter.

2. Raw material (1) Dicarboxylic acid component, terephthalic acid, isophthalic acid

(2) Diamine component, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,12-dodecanediamine

(3) Conductivity imparting agent / carbon fiber (CF) manufactured by Toho Tenax Co., Ltd., trade name “Besfight HTA-C6-NR”, average fiber diameter 7 μm, average fiber length 6 mm
・ Ketjen Black (CB) Product name “EC600JD” manufactured by Ketjen Black International
・ Stainless steel fiber (MF) Nippon Seisen Co., Ltd., trade name “Naslon SUS304”, average fiber diameter 8 μm, average fiber length 6 mm

(4) Fibrous reinforcing material / glass fiber (GF) manufactured by Asahi Fiber Glass Co., Ltd., trade name “03JAFT692”, average fiber diameter 10 μm, average fiber length 3 mm

Production Example 1
[Step (i)]
1,10-decanediamine (5050 parts by mass) as a diamine component, powdered terephthalic acid (4870 parts by mass) as a dicarboxylic component, benzoic acid (72 parts by mass) as a terminal blocking agent, sodium hypophosphite monohydrate as a polymerization catalyst The Japanese product (6 parts by mass) was placed in an autoclave and heated to 100 ° C., and then stirring was started at a rotation speed of 28 rpm using a double helical stirring blade, followed by heating for 1 hour. The molar ratio of the raw material monomers was 1,10-decanediamine: terephthalic acid = 50: 50. The mixture was heated to 230 ° C. while maintaining the rotation speed at 28 rpm, and subsequently heated at 230 ° C. for 3 hours. At that time, the formation reaction and crushing of the salt and the low polymer were carried out simultaneously. Thereafter, water vapor generated by the reaction was released to obtain a reaction product.

[Step (ii)]
The reaction product obtained in the step (i) was polymerized by heating at 230 ° C. for 5 hours in a dryer under a normal pressure nitrogen stream to obtain a polyamide (P-1).

Production Example 2
[Step (i)]
Terephthalic acid powder (4870 parts by mass) as a dicarboxylic component, sodium hypophosphite (6 parts by mass) as a polymerization catalyst, and benzoic acid (72 parts by mass) as a terminal blocking agent are placed in a ribbon blender reactor, and nitrogen is added. In a sealed state, the mixture was heated to 170 ° C. while stirring at a rotation speed of 30 rpm using a double helical stirring blade. Thereafter, decanediamine (5050 parts by mass) heated to 100 ° C. at a rate of 28 parts by mass at a rate of 28 parts by mass while maintaining the temperature at 170 ° C. and the number of revolutions at 30 rpm. The reaction product was obtained by adding continuously to the terephthalic acid powder over 3 hours (continuous liquid injection method). The molar ratio of the raw material monomers was 1,10-decanediamine: terephthalic acid = 50: 50.

[Step (ii)]
The reaction product obtained in step (i) was subsequently polymerized by heating to 230 ° C. under a nitrogen stream and heating at 230 ° C. for 5 hours in the ribbon blender reactor used in step (i). Polyamide (P-2) was obtained.

Production Examples 3-5, 7, 12
A polyamide was obtained in the same manner as in Production Example 2 except that the resin composition and production conditions were changed as shown in Table 1.

Production Example 6
[Step (i)]
1,10-decanediamine (5050 parts by mass) as a diamine component, powdered terephthalic acid (4870 parts by mass) as a dicarboxylic component, benzoic acid (72 parts by mass) as a terminal blocking agent, sodium hypophosphite monohydrate as a polymerization catalyst A Japanese product (6 parts by mass) and 400 parts by mass of distilled water (4 parts by mass with respect to 100 parts by mass of the total amount of raw material monomers) are placed in an autoclave, heated to 100 ° C., and then stirred at a rotational speed of 28 rpm. Heated for hours. The molar ratio of the raw material monomers was 1,10-decanediamine: terephthalic acid = 50: 50. The mixture was heated to 230 ° C. while maintaining the rotation speed at 28 rpm, and subsequently heated at 230 ° C. for 3 hours. At that time, the formation reaction and crushing of the salt and the low polymer were carried out simultaneously. Thereafter, water vapor generated by the reaction was released to obtain a reaction product.

[Step (ii)]
The reaction product obtained in the step (i) was polymerized by heating at 230 ° C. for 5 hours under a normal pressure nitrogen stream in a dryer to obtain a polyamide (P-6).

Production Example 8
[Step (i)]
1,10-decanediamine (5050 parts by mass) as a diamine component, powdered terephthalic acid (4870 parts by mass) with an average particle size of 80 μm as a dicarboxylic acid component, benzoic acid (72 parts by mass) as a terminal blocking agent, and the following as a polymerization catalyst Sodium phosphite monohydrate (6 parts by mass) and 9200 parts by mass of distilled water (92 parts by mass with respect to 100 parts by mass of the total amount of raw material monomers) were placed in an autoclave, heated to 100 ° C., and then rotated at 28 rpm. Stirring was started and heated for 1 hour. The molar ratio of the raw material monomers was 1,10-decanediamine: terephthalic acid = 50: 50. The mixture was heated to 230 ° C. while maintaining the rotation speed at 28 rpm, and subsequently heated at 230 ° C. for 3 hours. At that time, the formation reaction and crushing of the salt and the low polymer were carried out simultaneously. Thereafter, water vapor generated by the reaction was released to obtain a reaction product.

[Step (ii)]
The reaction product obtained in the step (i) was polymerized by heating at 230 ° C. for 5 hours in a dryer under a normal pressure nitrogen stream to obtain a polyamide (P-8).

  In Production Example 8, polymerization was performed using 92 parts by mass of distilled water with respect to 100 parts by mass of the total amount of raw material monomers. Therefore, compared with polyamide (P-1), the weight average molecular weight of the polyamide (P-8) was remarkably low, and the amount of triamine was remarkably large.

Production Example 9
A polyamide was obtained in the same manner as in Production Example 6 except that the amount of distilled water added was changed as shown in Table 1.

Production Examples 10 and 11
A polyamide was obtained in the same manner as in Production Example 1 except that the addition amount of the end-capping agent was changed.

  Table 1 shows the polyamide resin composition, production conditions, and characteristic values.

Example 1
100 parts by mass of polyamide (P-1) was weighed using a loss-in-weight continuous quantitative feeder CE-W-1 manufactured by Kubota Corporation, and the same direction twin screw extruder (Toshiba Machine Co., Ltd.) TEM37BS manufactured) was supplied to the main supply port, 5 parts by mass of carbon fiber (CF) was supplied from the side feeder, and melt kneading was performed. The barrel temperature setting of the extruder was 320 ° C. to 340 ° C., the screw rotation speed was 250 rpm, and the discharge amount was 35 kg / hour. Then, after taking up in strand form, it passed through the water tank, solidified by cooling, and it was cut with a pelletizer to obtain a polyamide resin composition.

Examples 2-18, Comparative Examples 1, 2, 4
As shown in Table 2, a polyamide resin composition was obtained in the same manner as in Example 1 except that the resin composition was changed.

Comparative Example 3
Although the same operation as Example 1 was performed, since content of the electroconductivity imparting agent was high, the strands were cut and a pellet of the polyamide resin composition could not be obtained.

  Table 2 shows the resin compositions and characteristic values of the polyamide resin compositions obtained in Examples and Comparative Examples.

In Examples 1 to 18, since the resin composition was prepared using the polyamide specified in the present invention and a predetermined amount of the conductivity-imparting agent, the molded bodies obtained therefrom were excellent in bending strength and bending elastic modulus and inherent in volume. The resistance value was low. Further, since the degree of supercooling of the polyamide used was 40 ° C. or less, the molding cycle during injection molding was short.
In Example 18, stearic acid was used as the end-capping agent, so that MFR was large and molding fluidity was good as compared with Example 2.

Since Comparative Example 1 did not add the conductivity imparting material, the volume resistivity value was high.
In Comparative Example 2, the molding cycle was long because the diamine component of the polyamide used was not a monomer defined in the present invention.
Since the content of the conductivity imparting material in Comparative Example 4 was less than 5 parts by mass, the volume specific resistance value was high.

Claims (6)

A conductive polyamide resin composition containing 100 parts by mass of a polyamide comprising a dicarboxylic acid component and a diamine component and 5 to 50 parts by mass of a conductivity-imparting agent, wherein the main component of the dicarboxylic acid component constituting the polyamide is terephthalic acid The main component of the diamine component is at least one selected from the group consisting of 1,8-octanediamine, 1,10-decanediamine and 1,12-dodecanediamine, and the differential scanning calorimeter of the polyamide is A conductive polyamide resin composition having a degree of supercooling measured by use of 40 ° C. or less. The conductive polyamide resin composition according to claim 1, wherein the polyamide is end-capped with a monocarboxylic acid having a molecular weight of 140 or more. The conductive amide resin composition according to claim 1 or 2, wherein the diamine component constituting the polyamide is 1,10-decanediamine. 4. The conductive polyamide resin composition according to claim 1, wherein the triamine unit is 0.3 mol% or less relative to the diamine unit in the polyamide. 5. The conductive polyamide resin composition according to claim 1, wherein the conductivity imparting agent is at least one selected from the group consisting of carbon black, carbon fiber, and metal fiber. The molded object formed by shape | molding the electroconductive polyamide resin composition in any one of Claims 1-5.