JP2010280875A - Polyamide resin composition excellent in conductivity and heat resistance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyamide resin composition excellent in conductivity and heat-resistance and a molded article formed from the composition. <P>SOLUTION: The polyamide resin composition includes a polyamide (A) obtained by polycondensing a diamine component containing ≥70 mol% of para-xylylenediamine and a dicarboxylic acid component and a conductive substance (B), and has volume resistivity of 10<SP>5</SP>Ω cm or less. A 4-20C α,ω-linear chain aliphatic carboxylic acid is preferable as the dicarboxylic acid component. The molded article formed from the resin composition is useful as a cell electrode or a separator. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a polyamide resin composition excellent in conductivity and heat resistance.

Polyamide resins have excellent properties such as strength, rigidity, solvent resistance, and moldability, so they are used as injection molding materials for automobiles, electrical and electronic parts, and packaging materials for foods, beverages, chemicals, and electronic parts. Yes.

On the other hand, the use of resins for battery electrodes, separator applications, and the like has been studied, and there is a demand for conductive resins. In recent years, there has been a demand for a resin having not only conductivity but also heat resistance.

As a battery separator using a conductive resin, a separator using polypropylene or the like is disclosed (see Patent Document 1), but this method has insufficient heat resistance. Moreover, as a battery electrode using a conductive resin, an electrode containing polyamide or the like and a conductive fiber has been disclosed (see Patent Document 2), but the disclosed method has insufficient heat resistance.

JP 2007-18850 A JP 2006-37001 A

An object of the present invention is to solve the above-described problems and provide a polyamide resin composition having excellent conductivity and heat resistance.

As a result of intensive studies, the present inventors include a polyamide (A) obtained by polycondensation of a diamine component containing 70 mol% or more of paraxylylenediamine and a dicarboxylic acid component, and a conductive substance (B). It has been found that a polyamide resin composition having a volume resistivity of 10 ⁵ Ω · cm or less solves the above problems.

The polyamide resin composition of the present invention has excellent conductivity and heat resistance, and a molded product using the polyamide resin composition can be used for battery parts and the like that require conductivity and heat resistance. The value is very high.

The polyamide resin composition of the present invention comprises a polyamide (A) obtained by polycondensation of a diamine component containing 70 mol% or more of paraxylylenediamine and a dicarboxylic acid component and a conductive substance (B), and has a volume resistivity. Is 10 ⁵ Ω · cm or less.

The polyamide (A) used in the present invention is obtained by polycondensation of a diamine component and a dicarboxylic acid component containing paraxylylenediamine in an amount of 70 mol% or more, more preferably 80 mol% or more, and still more preferably 90 mol% or more. Polyamide with good heat resistance. Examples of the polyamide (A) include polyamides obtained by polycondensation of a diamine component mainly composed of paraxylylenediamine and various dicarboxylic acid components. These polyamides may be homopolymers or copolymers. Polyamide (A) can be used by blending one or more resins.

Examples of diamine components other than paraxylylenediamine that can be used in the production of polyamide (A) include tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, Aliphatic diamines such as decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, 2,4,4-trimethylhexamethylenediamine; 1,3-bis (aminomethyl) cyclohexane, 1,4 -Bis (aminomethyl) cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis (4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (amino Alicyclic diamines such as til) decalin and bis (aminomethyl) tricyclodecane; diamines having aromatic rings such as bis (4-aminophenyl) ether, paraphenylenediamine, metaxylylenediamine, and bis (aminomethyl) naphthalene Examples and the like can be exemplified, but are not limited thereto.

Examples of the dicarboxylic acid component that can be used for producing the polyamide (A) include aliphatic dicarboxylic acids such as succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, adipic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid. An aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid or 2,6-naphthalenedicarboxylic acid can be exemplified, but is not limited thereto.

In addition to the diamine component and the dicarboxylic acid component, as a component constituting the polyamide resin composition, lactams such as ε-caprolactam and laurolactam, aliphatics such as aminocaproic acid and aminoundecanoic acid, as long as the effects of the present invention are not impaired. Aminocarboxylic acids can also be used as copolymerization components.

Examples of the polyamide (A) that can be used in the present invention include polyparaxylylene isophthalamide (PA-PXDI), caprolactam / paraxylylene isophthalamide copolymer (PA-6 / PXDI), and the like.

As the polyamide (A) that can be preferably used in the present invention, in addition to the above, a diamine component containing paraxylylenediamine and a dicarboxylic acid component mainly composed of an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms And polyamide obtained by polycondensation. Examples of the α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms include succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, adipic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid. Aliphatic dicarboxylic acids can be exemplified, but among these, adipic acid and sebacic acid are preferable, and sebacic acid is more preferable.
In the present invention, the α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms in the dicarboxylic acid component is preferably 50 mol% or more, more preferably 70 mol% or more, and further preferably 80 mol% or more. Preferably, 90 mol% or more is particularly preferable.

As the polyamide (A) that can be preferably used in the present invention, a diamine component containing paraxylylenediamine in an amount of 70 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more, an α, C 4-20, A polyamide obtained by polycondensation of a dicarboxylic acid component containing ω-linear aliphatic dicarboxylic acid with 50 mol% or more, preferably 70 mol% or more, more preferably 80 mol% or more, and further preferably 90 mol% or more. It can be illustrated. By making paraxylylenediamine in the diamine component 70 mol% or more, the obtained polyamide resin composition has a high melting point and high crystallinity, and is excellent in heat resistance, chemical resistance and the like as the polyamide resin composition of the present invention. It can be suitably used for the intended use.

Examples of such polyamides include polyamides obtained mainly by polycondensation of paraxylylenediamine and sebacic acid, and polyamides obtained mainly by polycondensation of paraxylylenediamine, adipic acid and sebacic acid, and the like. By using a mixture of adipic acid and sebacic acid as the dicarboxylic acid component, the heat resistance, gas barrier properties and crystallinity can be arbitrarily controlled. When it is desired to lower the crystallinity or when it is in an amorphous state, the sebacic acid / adipic acid ratio (molar ratio) is preferably 80/20 to 30/70, more preferably 70/30 to 40/60. When importance is attached to gas barrier properties, 50/50 or less is preferable, 40/60 or less is more preferable, and 30/70 or less is more preferable. When importance is attached to heat resistance, 60/40 or less is preferable, 40/60 or less is more preferable, and 30/70 or less is more preferable.

Moreover, the barrier property and molding processability of a polyamide resin (A) can be improved by adding metaxylylenediamine to paraxylylenediamine as a diamine component. Metaxylylenediamine can be added at an arbitrary ratio to control barrier properties and molding processability as long as it does not exceed 30 mol% of the diamine component. Suitable polyamide (A) includes paraxylylenediamine and metaxylylenediamine, a diamine component containing 70 mol% or more of paraxylylenediamine, and an α, ω-linear aliphatic group having 4 to 20 carbon atoms. Examples thereof include polyamides obtained by polycondensation with a dicarboxylic acid component containing 50 mol% or more of dicarboxylic acid.

The production method of the polyamide (A) is not particularly limited, and is produced by a conventionally known method and polymerization conditions. A small amount of monoamine or monocarboxylic acid may be added as a molecular weight regulator during the polycondensation of the polyamide. For example, a method in which an aqueous solution of a nylon salt of a diamine component and a dicarboxylic acid component is heated under pressure and polycondensed in a molten state while removing water and condensed water, and a diamine component is added directly to a dicarboxylic acid in a molten state. Examples of the method include polycondensation under a pressure or steam pressurized atmosphere. When polymerizing by directly adding diamine to molten dicarboxylic acid, in order to keep the reaction system in a uniform liquid state, diamine component is continuously added to the molten dicarboxylic acid phase so as not to lower the melting point of the resulting oligoamide and polyamide. The polycondensation proceeds while controlling the reaction temperature.

The polyamide (A) may be subjected to solid phase polymerization after being produced by a melt polymerization method. The production method of the polyamide (A) is not particularly limited, and is produced by a conventionally known method and polymerization conditions.

The number average molecular weight (Mn) of the polyamide (A) is preferably 15000 to 70000, more preferably 20000 to 50000 as a PMMA (polymethyl methacrylate) conversion value by GPC (gel permeation chromatography) measurement. Within this range, the heat resistance and moldability are good.

The melting point of the polyamide (A) is preferably 250 to 350 ° C. Heat resistance becomes favorable in it being this range.

The glass transition point (Tg) of the polyamide (A) is preferably 70 to 100 ° C. Within this range, the heat resistance is good.

The melting point and glass transition point can be measured by DSC (Differential Scanning Calorimetry) method. For the measurement, for example, DSC-50 manufactured by Shimadzu Corporation can be used, the amount of the sample is about 5 mg, and the heating rate can be measured by heating from room temperature to about 300 ° C. under the condition of 10 ° C./min. . The atmosphere gas was nitrogen at 30 ml / min. A so-called midpoint temperature (Tgm) was adopted as the glass transition point. As is widely known, Tgm is the midpoint temperature of the intersection of the tangent line of the glass state and the supercooled state (rubber state) of the base line and the tangent line of the transition slope in the DSC curve.

  A phosphorous compound can be added to the polyamide (A) in order to increase the processing stability during melt molding or to prevent the polyamide (A) from being colored. As the phosphorus compound, a phosphorus compound containing an alkali metal or an alkaline earth metal is preferably used. For example, an alkali metal or alkaline earth metal phosphate such as sodium, magnesium, calcium, hypophosphite, phosphorus Acid salts may be mentioned, but those using alkali metal or alkaline earth metal hypophosphites are particularly preferred because they are particularly excellent in the anti-coloring effect of polyamide. The density | concentration of a phosphorus compound is 1-500 ppm as a phosphorus atom, Preferably it is 1-350 ppm, More preferably, it is 1-200 ppm.

The polyamide resin composition of the present invention contains a conductive substance (B) as a constituent component other than polyamide. Carbon black, graphite, amorphous carbon powder, natural graphite powder, artificial graphite powder, carbon fiber, carbon nanotube, pulverized carbon fiber, hollow carbon fibril, copper, nickel, zinc, aluminum, etc. as the conductive substance (B) Examples thereof include powders or metal fibers, metal oxides, inorganic or organic compounds coated with a conductive substance, ionic or nonionic surfactants, and polymer antistatic agents. Among these, carbon black, graphite and carbon fiber are preferable. These conductive substances may be used alone or in combination of two or more.

Examples of the carbon black include, but are not limited to, acetylene carbon black, ketjen black, carbon black by an oil furnace method, and the like.

It is preferable that the compounding quantity of an electroconductive substance (B) is 5-80 weight part with respect to 100 weight part of polyamide (A). More preferably, it is 10-60 weight part, More preferably, it is 15-40 weight part. When it is in the above range, the conductivity is good and the moldability is also good.

The polyamide resin composition of the present invention has a volume resistivity of 10 ⁵ Ω · cm or less, preferably 10 ³ Ω · cm or less.

The polyamide resin composition of the present invention may contain an inorganic filler. By using an inorganic filler, the rigidity and dimensional stability of the molded product can be improved. Inorganic fillers are various fillers having a fiber shape, powder shape, granular shape, plate shape, cloth shape, mat shape, for example, glass fiber, talc, catalbo, diatomaceous earth, clay, kaolin, mica, granular glass, Known substances such as glass flakes and hollow glass can be used.

The polyamide resin composition of the present invention includes a matting agent, a weather resistance stabilizer, an ultraviolet absorber, a nucleating agent, a plasticizer, a flame retardant, an antistatic agent, an anti-coloring agent and a gel as long as the effects of the present invention are not impaired. Additives such as antioxidation agents, colorants, mold release agents, and the like can be added.

In addition, the polyamide resin composition of the present invention can be blended with one or more resins such as polyamide, polyester, polyolefin, polyphenylene sulfide, and polycarbonate other than polyamide (A) within a range that does not impair the purpose.

Especially, polyamides other than polyamide (A) can be blended preferably, More preferably, an aliphatic polyamide resin can be blended. The aliphatic polyamide resin is preferably used because it can improve the mechanical properties of the molded product. As the aliphatic polyamide resin, nylon 6, nylon 66, nylon 11, nylon 12, nylon 46, nylon 610, nylon 612, nylon 666, or the like can be used alone or in combination.

A molded product using the polyamide resin composition of the present invention has both conductivity and heat resistance, and is preferably usable for various parts. In particular, a molded article using the polyamide resin composition can be preferably used as a battery electrode or a separator.

Hereinafter, although an example and a comparative example explain the present invention still in detail, the present invention is not limited to these examples. In this example, various measurements were performed by the following methods.

(1) Conductivity JIS K7149 was used to determine volume resistivity (Ω · cm). It shows that electroconductivity is so favorable that volume resistivity is low. For the measurement, Lorester AP manufactured by Mitsubishi Oil Industries was used.

(2) Melting point of polyamide, glass transition point It was determined by differential scanning calorimetry (DSC) using DSC-60 manufactured by Shimadzu. Measurement conditions were about 5 mg of sample heated at 10 ° C./min, rapidly cooled when it reached 300 ° C. (some samples were 350 ° C.), and then heated again at 10 ° C./min. . In addition, the amorphous sample measured the sample which boiled the pellet and crystallized.

(3) Number average molecular weight Using an HLC-8320GPC manufactured by Tosoh, a PMMA conversion value was determined by GPC measurement. In addition, TSKgel SuperHM-H was used for the measurement column, hexafluoroisopropanol (HFIP) in which sodium trifluoroacetate was dissolved at 10 mmol / l was used as the solvent, and the measurement temperature was 40 ° C. A calibration curve was prepared by dissolving 6 levels of PMMA in HFIP.

<Production Example 1>
(Synthesis of polyamide (A1))
After sufficiently purging the inside of the reactor with nitrogen, sebacic acid (TA Grade manufactured by Ito Oil Co., Ltd.) was heated and melted at 170 ° C, and the contents were stirred while paraxylylenediamine (manufactured by Mitsubishi Gas Chemical Co., Ltd.) Was gradually added dropwise so that the molar ratio with sebacic acid was 1: 1, and the temperature was increased to 281 ° C. After completion of dropping, the temperature was raised to 300 ° C. After completion of the reaction, the contents were taken out in a strand shape and pelletized with a pelletizer.
The obtained pellets were charged into a tumbler and subjected to solid phase polymerization under reduced pressure to obtain a polyamide (A1) having a molecular weight adjusted.
Polyamide (A1) had a melting point of 280 ° C., a glass transition temperature of 75 ° C., and a number average molecular weight of 30000.

<Production Example 2>
(Synthesis of polyamide (A2))
After melting and dissolving sebacic acid in a reactor under a nitrogen atmosphere, the molar ratio of paraxylylenediamine and metaxylylenediamine (manufactured by Mitsubishi Gas Chemical Co., Ltd.) is 8: 2 while stirring the contents. The temperature was raised while the diamine was gradually added dropwise so that the molar ratio of diamine to dicarboxylic acid was 1: 1. After completion of dropping, stirring and reaction were continued until a predetermined viscosity was reached, and then the contents were taken out in a strand shape and pelletized with a pelletizer to obtain polyamide (A2). Polyamide (A2) had a melting point of 263 ° C., a glass transition temperature of 72 ° C., and a number average molecular weight of 17,000.

<Production Example 3>
(Synthesis of polyamide (A3))
A polyamide (A3) was synthesized in the same manner as in Production Example 2 except that a mixed diamine having a molar ratio of paraxylylenediamine to metaxylylenediamine of 9: 1 was used. Polyamide (A3) had a melting point of 271 ° C., a glass transition temperature of 74 ° C., and a number average molecular weight of 21,000.

<Production Example 4>
(Synthesis of polyamide (A4))
A polyamide (A4) was synthesized in the same manner as in Production Example 1 except that a mixed dicarboxylic acid having a molar ratio of sebacic acid and adipic acid (made by Rhodia) of 4: 6 was used instead of sebacic acid. Polyamide (A4) had a melting point of 297 ° C., a glass transition temperature of 83 ° C., and a number average molecular weight of 60000.

<Production Example 5>
(Synthesis of polyamide (A5))
A polyamide (A5) was synthesized in the same manner as in Production Example 2 except that adipic acid was used instead of sebacic acid and a mixed diamine having a molar ratio of paraxylylenediamine to metaxylylenediamine of 7: 3 was used. Polyamide (A5) had a melting point of 299 ° C., a glass transition temperature of 94 ° C., and a number average molecular weight of 45,000.

<Example 1>
Polyamide (A1), graphite (natural scaly graphite grade CP made by Nippon Graphite Co., Ltd.) and carbon black (Vulcan XC made by Cabot Corp.) were melt-kneaded with a twin screw extruder to be pelletized. The obtained pellets were extruded using a single screw extruder equipped with a 30 mmφ screw and a T die to obtain a film having a thickness of 100 μm. Table 1 shows the composition and evaluation results of the polyamide resin composition.

<Examples 2 to 5>
A film was obtained in the same manner as in Example 1 except that the polyamide resin composition was as described in Table 1. The evaluation results are shown in Table 1.

<Comparative Example 1>
A film was obtained in the same manner as in Example 1 except that the polyamide resin composition was as described in Table 1. The evaluation results are shown in Table 1.

The abbreviations listed in Table 1 are as follows.
A1: Polyamide (A1) obtained in Production Example 1
A2: Polyamide (A2) obtained in Production Example 2
A3: Polyamide (A3) obtained in Production Example 3
A4: Polyamide (A4) obtained in Production Example 4
A5: Polyamide obtained in Production Example 5 (A5)
S6007: Polyamide composed of adipic acid and metaxylylenediamine (MX nylon grade S6007 manufactured by Mitsubishi Gas Chemical Co., Inc.), melting point 240 ° C., number average molecular weight 45,000.
Carbon 1: Graphite (Natural scaly graphite grade special CP manufactured by Nippon Graphite Co., Ltd.)
Carbon 2: Carbon black (Vulcan XC manufactured by Cabot)
Carbon 3: Ketjen Black (Lion Corporation grade EC600JD)

As shown in the above examples, the polyamide resin composition containing the polyamide (A) and the conductive substance (B) had excellent conductivity and heat resistance.

Claims (8)

The volume resistivity is 10 ⁵ Ω · cm or less, including a polyamide (A) obtained by polycondensation of a diamine component containing 70 mol% or more of paraxylylenediamine and a dicarboxylic acid component and a conductive substance (B). Polyamide resin composition. The polyamide resin composition according to claim 1, wherein the polyamide (A) has a glass transition point Tg of 70 to 100 ° C. The polyamide (A) is a polycondensation of a diamine component containing 70 mol% or more of paraxylylenediamine and a dicarboxylic acid component containing 50 mol% or more of an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The polyamide resin composition according to claim 1, wherein the polyamide resin composition is a polyamide obtained. Polyamide (A) includes paraxylylenediamine and metaxylylenediamine, and a diamine component in which paraxylylenediamine is 70 mol% or more, and an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The polyamide resin composition according to claim 1 or 2, which is a polyamide obtained by polycondensation with a dicarboxylic acid component containing 50 mol% or more. The polyamide resin composition according to claim 1 or 2, wherein the polyamide (A) is a polyamide obtained mainly by polycondensation of paraxylylenediamine and sebacic acid. The polyamide resin composition according to claim 1 or 2, wherein the polyamide (A) is a polyamide obtained mainly by polycondensation of paraxylylenediamine, adipic acid and sebacic acid. A molded article using the polyamide resin composition according to any one of claims 1 to 6. The molded article according to claim 7, wherein the molded article is a battery electrode or a separator.