WO2009087798A1

WO2009087798A1 - Gasket for battery and alkaline battery

Info

Publication number: WO2009087798A1
Application number: PCT/JP2008/068419
Authority: WO
Inventors: Seiji Wada
Original assignee: Panasonic Corporation
Priority date: 2008-01-11
Filing date: 2008-10-10
Publication date: 2009-07-16

Abstract

It is intended to provide a gasket for a battery made from a polyamide resin composition which provides a molded article having a mechanical strength equal to or higher than that of a conventional article and showing a sufficiently small decrease in mechanical strength due to a chemical in an environment of excessive contact with the chemical, and showing a sufficiently small change in mechanical strength or appearance due to a chemical, water in a chemical or water in air. The gasket for a battery of the invention is obtained by molding the polyamide resin composition which contains (A) a polyamide resin composed of polyhexamethylene sebacamide and/or polyhexamethylene dodecamide, (B) boron nitride, and (C) baked kaolin.

Description

Battery gasket and alkaline battery

The present invention relates to a battery gasket and an alkaline battery obtained by using a polyamide resin composition.

Conventionally, polyamide resins are widely used in various parts such as automobile parts, electronic / electric parts, and industrial machine parts because they are excellent in various characteristics including mechanical characteristics, such as molding processability. However, with the recent sophistication of the industry, polyamide resins have been required to have various properties that have not been conventionally required.

For example, attempts have been made to replace metal automobile parts, electronic / electric parts, and industrial machine parts with polyamide resin by utilizing the excellent moldability of the polyamide resin. However, polyamide resins are generally not excellent in water resistance. Then, the polyamide resin composition which reduced the water absorption rate is proposed for the purpose of improving the water resistance (for example, refer patent document 1). Such a polyamide resin composition is said to be a polyamide resin composition having excellent water resistance as compared with conventional ones. Moreover, the polyamide resin composition which improved the heat-and-moisture resistance is proposed (for example, refer patent document 2). This composition is said to be a polyamide resin composition excellent in moldability and heat-and-moisture resistance as compared with the conventional one.
JP 2000-86890 A JP 2005-78890 A

However, with the changes in the usage environment of polyamide resins, the required specifications required for polyamide resins are becoming stricter year by year. Therefore, even if it is a polyamide resin composition as described in patent document 1, 2, the specification cannot fully be satisfied.

Recently, one of the specifications required for polyamide resin is a specification that is excellent in balance between chemical resistance such as alkali resistance and calcium chloride resistance and mechanical properties. More specifically, the molded product obtained from the polyamide resin has a mechanical strength equivalent to or higher than that of the conventional one, and there is little decrease in mechanical strength due to the chemical in an environment where the molded product is excessively in contact with the chemical. There is a need for a polyamide resin composition that has little change in mechanical strength and appearance due to moisture in the atmosphere and moisture in the atmosphere.

The present invention has been made in view of the above circumstances, and the obtained molded product has a mechanical strength equivalent to or higher than that of the conventional one, and the mechanical strength is reduced by the chemical in an environment where it is excessively in contact with the chemical. It is an object of the present invention to provide a battery gasket and an alkaline battery that are obtained from a polyamide resin composition that is sufficiently small and that has a sufficiently small change in mechanical strength and appearance due to chemicals, moisture in the chemicals, and moisture in the atmosphere.

As a result of intensive studies to achieve the above object, the present inventors have found that a polyamide resin composition obtained by blending boron nitride and calcined kaolin with a specific polyamide resin is effective in achieving the above object. As a result, the present invention has been completed.

That is, the present invention provides the following.
[1] A polyamide resin composition containing (A) a polyamide resin composed of polyhexamethylene sebacamide and / or polyhexamethylene dodecamide, (B) boron nitride, and (C) calcined kaolin is molded. Battery gasket obtained.
[2] The polyamide resin composition contains 0.0001 to 3 parts by mass of component (B) and 0.01 to 20 parts by mass of component (C) with respect to 100 parts by mass of component (A). The battery gasket of [1] above.
[3] The [1] or [2], wherein the polyamide resin composition contains (D) 1 to 20 parts by mass of a polyamide resin different from the component (A) with respect to 100 parts by mass of the component (A). Battery gasket.
[4] The battery gasket according to any one of [1] to [3], wherein the powder (B) has an average powder particle size of 10 μm or less.
[5] The polyamide resin composition according to any one of [1] to [4], wherein the polyamide resin composition contains 100 to 20000 parts by mass of the component (C) with respect to 100 parts by mass of the component (B). object.
[6] An alkaline dry battery comprising the battery gasket according to any one of [1] to [5] above.

According to the present invention, the obtained molded article has a mechanical strength equivalent to or higher than that of the conventional one, and in an environment where the molded product is excessively contacted with the chemical, the decrease in mechanical strength due to the chemical is sufficiently small. It is possible to provide a battery gasket and an alkaline battery obtained from a polyamide resin composition in which mechanical strength and appearance change due to moisture in chemicals and moisture in the atmosphere are sufficiently small.

It is a typical section front view showing an example of the gasket for batteries of this embodiment. It is a typical half section front view showing an AA alkaline dry battery which is an example of this embodiment. It is a typical section front view showing the metal mold for injection molding concerning an example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Battery gasket, 2 ... Positive electrode, 3 ... Gel-like negative electrode, 4 ... Separator, 5 ... Battery case, 6 ... Negative electrode collector, 7 ... Negative electrode terminal board, 8 ... Exterior label, 9 ... Sealing unit, 10 ... Alkaline battery, 20 ... mold, 28 ... molded product.

Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

The polyamide resin composition of this embodiment contains (A) a polyamide resin composed of polyhexamethylene sebacamide and / or polyhexamethylene dodecamide, (B) boron nitride, and (C) calcined kaolin. It is. Hereinafter, each component will be described in detail.

<(A) component>
The component (A) is a polyamide resin composed of polyhexamethylene sebacamide and / or polyhexamethylene dodecamide. Polyhexamethylene sebacamide is also referred to as “polyamide 610”, and polyhexamethylene dodecamide is also referred to as “polyamide 612”. The component (A) preferably contains at least polyhexamethylene dodecamide, and more preferably consists of polyhexamethylene dodecamide. Thereby, the object of the present invention can be achieved more reliably and effectively. These can be obtained by obtaining commercially available products or by synthesizing them by conventional methods.

The degree of polymerization of the polyamide resin as component (A) is preferably such that the relative viscosity at 25 ° C. is 1.8 to 3.8, more preferably 1.9 to 3.5. More preferably, the degree of polymerization is 2.0 to 3.3. Here, the “relative viscosity” is measured using an Ostwald viscometer in a 98% concentrated sulfuric acid solution containing 1% by mass of a polyamide resin. By controlling the degree of polymerization so that the relative viscosity of the polyamide resin as the component (A) is in the above numerical range, the polyamide resin composition of the present embodiment is further excellent in moldability and mechanical strength.

<(B) component>
The boron nitride component (B) is represented by the chemical formula “BN”. This boron nitride is obtained by heating boron at a high temperature in a nitrogen stream, heating ammonia and boron oxide, or heating ammonium chloride and borax. The boron nitride thus obtained is a fine powder. The powder average particle size of boron nitride is preferably 10 μm or less, and more preferably 0.1 to 10 μm. Here, “powder average particle size” means the particle size distribution of powder measured using a commercially available particle size distribution measuring device (for example, a laser diffraction particle size distribution measuring device manufactured by Shimadzu Corporation, trade name “SALD-2200”). Means a particle size (so-called “D50”) when occupying 50% of the mass of the whole powder. By controlling the average particle size of the boron nitride powder within the above numerical range, structural defects that can occur in the molded product obtained from the polyamide resin composition of the present embodiment tend to be more effectively prevented. . By preventing structural defects in the molded product in this way, the object of the present invention can be achieved more reliably and effectively.

By including this component (B), the polyamide resin composition of the present embodiment contains a change in mechanical strength due to moisture in the medicine or in the medicine or in the atmosphere when in contact with the medicine, particularly impact strength. Can be suppressed. Such a suppression effect can be clearly recognized when compared with the case where the polyamide resin composition contains a crystal nucleating agent different from boron nitride.

<(C) component>
The calcined kaolin as the component (C) is metakaolin (Al ₂ O ₃ .2SiO ₂ ) obtained by calcining kaolinite and dehydrating, and is amorphous in terms of X-rays. The shape of the calcined kaolin is not particularly limited, but is preferably a non-fibrous shape such as a plate shape, a rod shape, or a spherical shape. Thereby, the effect that the anisotropy of the dimension at the time of shape | molding a polyamide resin composition and obtaining a molded article and a mechanical characteristic hardly arises is acquired. The average particle diameter of the calcined kaolin is preferably 0.05 to 10 μm from the viewpoint of more effectively achieving the object of the present invention. The calcined kaolin can be obtained by obtaining a commercially available product, by synthesizing by a conventional method, or by obtaining commercially available kaolinite and dehydrating it by a conventional method.

The calcined kaolin which is the component (C) is preferably subjected to surface treatment from the viewpoint of more effectively achieving the object of the present invention. Examples of such surface treatment include surface treatment in which calcined kaolin is brought into contact with a coupling agent such as an isocyanate compound, an organic silane compound, an organic titanate compound, an organic borane compound, or an epoxy compound.

Among these coupling agents, organosilane compounds (silane coupling agents) are preferable. Specific examples thereof include epoxy group-containing alkoxysilanes represented by γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. Compounds, γ-mercaptopropyltrimethoxysilane, mercapto group-containing alkoxysilane compounds represented by γ-mercaptopropyltriethoxysilane, γ-ureidopropyltriethoxysilane, γ-ureidopropyltrimethoxysilane, γ- (2- Ureido group-containing alkoxysilane compounds represented by ureidoethyl) aminopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropylmethyldimethoxy Isocyanato group-containing alkoxysilane compounds represented by silane, γ-isocyanatopropylmethyldiethoxysilane, γ-isocyanatopropylethyldimethoxysilane, γ-isocyanatopropylethyldiethoxysilane, γ-isocyanatopropyltrichlorosilane, γ -(2-aminoethyl) aminopropylmethyldimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldiethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) Amino group-containing alkoxysilane compounds represented by aminopropyltriethoxysilane, γ-aminotrimethoxysilane, γ-aminotriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ- Hydroxyl-containing alkoxysilane compounds represented by droxypropyltrimethoxysilane, γ-hydroxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) -Carbon-carbon unsaturated bond-containing alkoxysilane compounds represented by -γ-aminopropyltrimethoxysilane hydrochloride. Among these organosilane compounds, in particular, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ- (2-aminoethyl) ) Aminopropylmethyldiethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropyltriethoxysilane, γ-aminotrimethoxysilane, γ-aminotriethoxysilane, γ-aminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane are preferably used.

¡Coupling agents may be used alone or in combination of two or more.

In the polyamide resin composition of the present embodiment, the composition ratio of the above components is not particularly limited as long as it does not impair the object of the present invention, but is preferably as follows. That is, the polyamide resin composition of the present embodiment has a content of 0.0001 to 3 parts by mass of component (B) with respect to 100 parts by mass of component (A), from the viewpoint of more reliably and effectively achieving the object of the invention. It is preferably contained in an amount of 0.001 to 2 parts by mass, more preferably 0.01 to 1 part by mass.

In addition, the polyamide resin composition of the present embodiment is based on 100 parts by mass of component (A) from the viewpoint of further suppressing changes in strength due to chemicals, moisture in the chemicals, moisture in the atmosphere, especially changes in impact strength. The component (C) is preferably contained in an amount of 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, and further preferably 0.5 to 10 parts by mass.

From the viewpoint of more effectively exhibiting the effects obtained by the present invention, the polyamide resin composition of the present embodiment preferably contains 100 to 20000 parts by mass of the component (C) with respect to 100 parts by mass of the component (B). The content is more preferably 500 to 18000 parts by mass, and even more preferably 1000 to 15000 parts by mass.

<(D) component>
The polyamide resin composition of the present embodiment may further contain a polyamide resin that is different from the component (A) as long as the object of the present invention is not impaired. Thereby, the effect that crystallinity can be improved or heat resistance can be improved is obtained. As such a polyamide resin, for example, polyhexamethylene adipamide (polyamide 66), polyε capramide (polyamide 6), a copolymer of polyhexamethylene adipamide and polyisophthalamide (polyamide 6I), Examples thereof include a copolymer of polyhexamethylene adipamide and polyterephthalamide (polyamide 6T), and a terpolymer of polyhexamethylene adipamide, polyisophthalamide and polyterephthalamide. These polyamide resins are used alone or in combination of two or more. The content is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the component (A). By adjusting the content ratio within this numerical range, an effect of excellent balance of chemical resistance, mechanical properties and heat resistance tends to be obtained.

The degree of polymerization of the different type of polyamide resin as component (D) is preferably such that the relative viscosity at 25 ° C. is 1.8 to 3.8, and the degree of polymerization is 1.9 to 3.5. More preferably, the degree of polymerization is 2.0 to 3.3. Further, the relative viscosity at 25 ° C. of the mixture of the component (A) and a polyamide resin different from this is preferably 1.8 to 3.8, more preferably 1.9 to 3.5. More preferably, it is 0.0 to 3.3. As a result, the polyamide resin composition of the present embodiment is further excellent in moldability and mechanical strength.

The polyamide resin composition of the present embodiment includes, in addition to the above-described components, inorganic fillers, flame retardants, and pigments contained in ordinary polyamide resin compositions, as long as they do not impair the purpose of the present invention. Or a colorant. Furthermore, the polyamide resin composition of the present embodiment may be added with various additives such as a moldability improver, a heat stabilizer, a light stabilizer, an antioxidant, and an antistatic agent in any stage within a range not impairing the object of the present invention. May be added. These are used singly or in combination of two or more.

The polyamide resin composition of the present embodiment may contain a polymer other than the above-described polyamide resin as long as it does not hinder the object of the present invention. Examples of such a polymer include polypropylene, ABS resin, polyphenylene oxide, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyarylate, liquid crystal polyester, and various elastomers. These are used singly or in combination of two or more.

The polyamide resin composition of the present embodiment can be produced by the same method as the conventional polyamide resin composition. For example, when mixing the boron nitride of component (B) with the polyamide resin of component (A), it may be added to the raw material of component (A) during the synthesis of component (A), or during melt kneading of component (A) It may be added. Alternatively, the component (A) may be blended and added to the pellet surface after the component (A) is formed into a pellet, or the component (B) may be added as a high-concentration master batch.

Further, the calcined kaolin of the component (C) may be added to the raw material of the component (A) when the component (A) is synthesized, or may be added when the component (A) is melt-kneaded. When the component (C) is added when the component (A) is melt-kneaded in the extruder, the pellets of the component (A) and the component (C) are weighed in advance and then hand-blended, and these are simultaneously fed to the extruder. You may supply. Or the pellet of (A) component may be supplied from the upstream of an extruder, and (C) component may be supplied to an extruder, after (A) component fully fuse | melts.

When the surface treatment is performed on the calcined kaolin of component (C) using the above coupling agent, the component (C) is subjected to surface treatment with these coupling agents in accordance with a conventional method before the component (A). It is preferable to mix with a polyamide resin. However, a so-called integral blend method in which a coupling agent is added when melt kneading with the component (A) without subjecting the component (C) to surface treatment in advance may be used.

The polyamide resin composition of the present embodiment described above is blended with a specific ratio of boron nitride as the component (B) and calcined kaolin as the component (C) to the polyamide resin as the component (A) as a matrix. It is uniformly and finely dispersed. As a result, the molded product obtained from the polyamide resin composition of the present embodiment has a mechanical strength equivalent to or higher than that of the conventional one, and the mechanical strength is sufficiently lowered by the chemical in an environment where it is in excessive contact with the chemical. And the change in mechanical strength and appearance due to chemicals, moisture in the chemicals and moisture in the atmosphere is sufficiently reduced. Therefore, the battery gasket obtained by molding the polyamide resin composition of the present embodiment has extremely excellent alkali resistance and liquid leakage resistance.

Further, the polyamide resin composition of the present embodiment has good moldability, and is particularly excellent in releasability. Therefore, when the polyamide resin composition of the present embodiment is used, a molded product having excellent mass productivity can be obtained.

The polyamide resin composition of the present embodiment is not limited to battery gaskets, and can be molded into various molded products. In order to effectively utilize the above-described characteristics, automotive parts, electronic / electrical parts, industrial machinery Application to various parts such as parts is expected. Specific examples of molded products obtained by molding the polyamide resin composition of the present embodiment include battery gaskets, water inlets, water outlets, radiator tanks, hot water tanks, water pumps, connectors, various switches, and engine covers. Can be mentioned.

These molded products are not particularly limited in shape, except that the polyamide resin composition of the present embodiment is adopted as a raw material, and may be the same as known ones, and can be manufactured by a conventionally known method. . As the molding method, there are known molding methods such as press molding, injection molding, gas assist injection molding, welding molding, extrusion molding, blow molding, film molding, hollow molding, multilayer molding, etc. Can be mentioned. Even if these molding methods are used, good molding processing is possible, and the above-mentioned molded product can be obtained. Among these, it is preferable to form the molded product by injection molding from the viewpoint that it can be efficiently produced by utilizing the characteristics of polyamide having good fluidity and good releasability (high cycle moldability).

Next, the battery gasket of this embodiment will be described with reference to the drawings as necessary. The battery gasket of the present embodiment is a sealing part for alkaline dry batteries and alkaline button type batteries that are generally widely distributed. If the polyamide gasket is obtained by molding the polyamide resin composition of the present embodiment, its shape and the like are There is no particular limitation. The battery gasket of the present embodiment has a function of sealing the opening of a bottomed battery case containing a power generation element containing an alkaline electrolyte to keep the battery sealed. This battery gasket is obtained by molding the polyamide resin composition of this embodiment into a predetermined shape. The battery gasket of the present embodiment may be partially provided with a thin portion having a thickness of about 0.1 to 0.4 mm that acts as a safety valve when the battery is misused.

Since the battery gasket of the present embodiment has good alkali resistance, it is possible to impart excellent chemical resistance and liquid leakage resistance to an alkaline dry battery equipped therewith. In addition, since this battery gasket has good moldability and is particularly excellent in releasability, it can be molded in the same excellent molding cycle as that of the polyamide 66 battery gasket.

FIG. 1 is a schematic cross-sectional front view showing an example of the battery gasket of the present embodiment. The battery gasket 1 is provided with a cylindrical outer wall 1d on the outer peripheral portion, a central boss 1a provided with a through-hole for press-fitting and inserting other parts to be described later in the center, and a connecting portion 1c provided therebetween. Are formed continuously. The connecting portion 1c is provided with a thin-walled portion 1b that acts as a safety valve so as to break when a certain pressure is reached when an abnormal pressure rise occurs inside the battery. The thickness of the thin portion 1b is sufficiently thin with respect to the thickness of the connecting portion 1c, and is set to 0.2 to 0.3 mm.

Next, the alkaline dry battery and alkaline button type battery of this embodiment will be described with reference to the drawings as necessary. In the alkaline dry battery and alkaline button type battery of this embodiment, other components may be conventionally known as long as the battery gasket provided is the battery gasket of this embodiment.

FIG. 2 is a schematic half-sectional front view showing an AA alkaline battery which is an example of the present embodiment. The alkaline dry battery 10 includes a bottomed cylindrical battery case 5 and a hollow cylindrical positive electrode 2 accommodated therein so as to be inscribed therein. A gelled negative electrode 3 is disposed in the hollow portion of the positive electrode 2 with a bottomed cylindrical separator 4 interposed therebetween. Most of the needle-shaped negative electrode current collector 6 is immersed in the gelled negative electrode 3, and one end of the negative electrode current collector 6 not immersed in the gelled negative electrode 3 is the center of the disk-shaped negative electrode terminal plate 7. It is electrically connected to the part. Furthermore, the negative electrode current collector 6 and the negative electrode terminal plate 7 are integrated with the battery gasket 1 described above to constitute a sealing unit 9. The battery gasket 1 is in contact with the opening end of the separator 4 at the connecting portion 1c, and the cylindrical outer wall portion 1d is sandwiched and fixed between the opening end of the battery case 5 and the outer edge portion of the negative electrode terminal plate 7. In such a configuration, in the battery case 5, the power generation elements such as the positive electrode 2 and the gelled negative electrode 3 containing an alkaline electrolyte are accommodated, and the sealing unit 9 is arranged as illustrated, and then the opening end of the battery case 5 is opened. It is obtained by folding inward in an arc shape and sealing. The outer peripheral surface of the battery case 5 is covered with an exterior label 8 to ensure insulation.

As the alkaline electrolyte, an aqueous solution containing 30 to 40% by mass of potassium hydroxide and 1 to 3% by mass of zinc oxide is generally used. A battery gasket obtained by molding a conventional polyamide resin or a composition thereof is hydrolyzed by an alkaline electrolyte, resulting in a decrease in mechanical strength. There is also. Therefore, in order to maintain the function of the thin portion 1b for a long time after the battery is manufactured, the battery gasket is required to have high chemical resistance (strong alkali resistance). The battery gasket of the present embodiment has been completed to meet such demands, and is a battery gasket that is sufficiently excellent in chemical resistance (alkali resistance). Therefore, the alkaline dry battery and the alkaline button battery provided with this battery gasket exhibit sufficiently good leakage resistance.
According to this embodiment, the molded product obtained by molding has a mechanical strength equivalent to or higher than that of the conventional one, and in an environment where it is in excessive contact with the chemical, the mechanical strength is sufficiently lowered or deteriorated by the chemical. It is possible to provide a polyamide resin composition that is useful as a gasket for a battery with a small amount and sufficient change in mechanical strength and appearance due to chemicals, moisture in the chemicals, and moisture in the atmosphere.

The best mode for carrying out the present invention has been described above, but the present invention is not limited to the above embodiment. The present invention can be variously modified without departing from the gist thereof.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Various physical properties and characteristics were evaluated as shown in the following (1) to (6).

(1) Relative viscosity of polyamide resin The relative viscosity (ηr) at 25 ° C. of the polyamide resin was measured according to JIS K6810 using an Ostwald viscometer in a 98% concentrated sulfuric acid solution containing 1% by mass of the polyamide resin. .

(2) Average particle size of powder In the particle size distribution of powder measured using a laser diffraction particle size distribution measuring device (trade name “SALD-2200”) manufactured by Shimadzu Corporation, it accounts for 50% of the total powder mass. The particle size (D50) at the time was determined as the average particle size of the powder.

(3) Chemical resistance test of molded product (3-1) Production of molded product First, various tests were conducted by molding a polyamide resin composition with an injection molding machine (trade name “PS60E” manufactured by Nissei Plastic Co., Ltd.). A molded product to be used for was prepared. The cylinder temperature was set to 270 ° C., the mold temperature was set to 80 ° C., and molding was performed under injection molding conditions of injection for 10 seconds and cooling for 15 seconds. As molded articles, ASTM dumbbell type test piece type 1 (test piece thickness: 1/8 inch, hereinafter referred to as “dumbbell type test piece”) and ASTM strip type test piece type 1 (test piece thickness: 1/8 inch, below) "Striped specimen"). Of these, the strip-shaped test piece was further cut to obtain a notched test piece (test piece thickness: 1/8 inch) for an Izod impact test.

(3-2) Chemical treatment of molded article The above-mentioned dumbbell-shaped test piece and the notched test piece were immersed in a 3% by mass calcium chloride aqueous solution at 60 ° C for 500 hours for chemical resistance test. The surface appearance, tensile properties, and Izod impact value of the test pieces before and after the chemical resistance test were evaluated as follows.

(3-3) Surface appearance test (a) Surface appearance before chemical resistance test Handy gloss meter (trade name "IG320") manufactured by HORIBA, Ltd. for the surface of the dumbbell-shaped test piece before the chemical resistance test. The specular gloss Gs (60 °) was measured according to JIS Z 8741.

(B) Surface appearance after chemical resistance test The dumbbell-shaped test piece after the above chemical resistance test was taken out of the calcium chloride aqueous solution, wiped on the surface, and left in a room at room temperature of 23 ° C. and relative humidity of 55% for 1 hour. . Subsequently, the specular gloss Gs (60 °) of the surface of the dumbbell-shaped test piece was measured in the same manner as in the above (a).

(C) Specular Gloss Retention Rate The specular gloss Gs after the chemical resistance test / the specular gloss Gs × 100 before the chemical resistance test was calculated as the specular gloss retention (unit:%). It shows that a test piece is excellent in chemical resistance, so that this retention rate is high.

(3-4) Tensile test (d) Tensile strength before chemical resistance test The dumbbell-shaped test piece in the dry state (usually so-called absolutely dry state) before the chemical resistance test is in accordance with ASTM D638. Tensile strength (unit: MPa) was measured.

(E) Tensile strength after chemical resistance test The dumbbell-shaped test piece after the above chemical resistance test was taken out of the calcium chloride aqueous solution, wiped on the surface, and left in a room at room temperature of 23 ° C and relative humidity of 55% for 1 hour. . Subsequently, the tensile strength (unit: MPa) was measured for the dumbbell-shaped test piece in accordance with ASTM D638.

(F) Tensile strength retention ratio Tensile strength after chemical resistance test (unit: MPa) ÷ Tensile strength before chemical resistance test (unit: MPa) x 100 Tensile strength retention ratio (unit:%) Calculated as A higher retention rate indicates that the test piece is more excellent in tensile properties, which is one of the mechanical strengths.

(3-5) Izod impact test (g) Izod impact value before chemical resistance test Notched test piece in the dry state (usually so-called absolutely dry state) before the above chemical resistance test conforms to ASTM D256 The Izod impact value (unit: J / m) was measured.

(H) Izod impact value after chemical resistance test Take out the notched specimen after the chemical resistance test from the calcium chloride aqueous solution, wipe the surface, and leave it in a room at room temperature of 23 ° C and relative humidity of 55% for 1 hour. I put it. Next, the Izod impact value (unit: J / m) was measured for the notched test piece in accordance with ASTM D256.

(I) Retention rate of Izod impact value The Izod impact value after chemical resistance test (unit: J / m) ÷ Izod impact value before chemical resistance test (unit: J / m) x 100 is the Izod impact value. Was calculated as a retention rate (unit:%). The higher the retention rate, the better the test piece is in impact resistance, which is one of the mechanical strengths.

(4) Chemical resistance test of battery gasket First, the polyamide resin composition was molded by injection molding to obtain a battery gasket having the same shape as in FIG. However, the thickness of the thin portion (corresponding to the portion indicated by reference numeral 1b in FIG. 1) was adjusted so that the operating pressure described later was about 8 MPa. As for injection molding conditions, the cylinder temperature was set to 290 ° C., the mold temperature was set to 80 ° C., injection was set to 4 seconds, and cooling was set to 10 seconds. And after filling the aqueous solution which contains potassium hydroxide 34.5 mass% and zinc oxide 2.0 mass% in the container with a lid | cover, the said battery gasket was immersed, the container was sealed, and 80 degreeC was sealed. In an environmental test tank for 3 months. Thereafter, the battery gasket was taken out of the container, washed with water and dried with warm air.

This battery gasket was subjected to a chemical resistance test as follows. First, there is a path through which oil for oil pressure measurement flows, and a central boss part (corresponding to a part indicated by reference numeral 1a in FIG. 1) and a cylindrical outer wall part (part indicated by reference numeral 1d in FIG. 1) of the battery gasket. And a test jig for sealing the whole battery gasket was prepared. This test jig is provided with a hydraulic gauge so that the oil that has flowed in immerses the entire battery gasket, the hydraulic pressure of which is adjustable. The test gasket was stored with the battery gasket before being immersed in the aqueous solution, filled with oil, and the battery gasket was immersed in the oil. Thereafter, the oil pressure of the oil immersed in the battery gasket was gradually increased, and the oil pressure (unit: MPa) when the thin portion of the battery gasket was broken was measured. The hydraulic pressure at the time of fracture corresponds to a pressure at which the thin portion of the battery gasket operates as a safety valve (hereinafter referred to as “operating pressure”). Next, the operating pressure of the battery gasket after drying with hot air was measured in the same manner. The operating pressure (unit: MPa) for the battery gasket before immersion / the operating pressure (unit: MPa) for the battery gasket after drying with hot air × 100 was calculated as the holding ratio (unit:%) of the operating pressure. It was judged that the chemical resistance of the battery gasket was good when the retention rate was 80% or more.

(5) Leakage resistance test of alkaline battery AA alkaline batteries having the same structure as that shown in FIG. 1 except that various polyamide resin compositions were used as raw materials for battery gaskets were evaluated as follows. Carried out. First, 20 each of the dry batteries were stored in an environmental test tank at 80 ° C. for 3 months. Thereafter, the battery was taken out of the environmental test tank and visually checked for leakage of the alkaline electrolyte. Further, the battery in which the liquid leakage occurred was disassembled and the battery gasket was taken out. The battery gasket was observed with an optical microscope, and it was confirmed whether or not the thin-walled portion was cracked to cause leakage, and the number of dry batteries that had reached leakage was counted.

(6) Release force The release force of the molded product was measured by the following method to evaluate the release property. First, the metal mold | die 20 which shows a cross section in FIG. 3 was prepared. Next, the molten polyamide resin composition was injected into the mold 20. The injected polyamide resin composition was filled into the box mold cavity 22 via the sprue runner 21. Next, the polyamide resin composition was sufficiently cooled in the mold 20 so that the polyamide resin was cured. Thereafter, the mold 20 is separated between the mold part 20 a provided with the sprue runner 21 and the mold part 20 b provided with the box-shaped molding cavity 22, and the pressure sensor 25, the ejector plate 24 and the ejector are ejected by the ejector rod 26. A molded product 28 in which the polyamide resin composition was solidified protruded in the direction of the arrow through the pin 23. The force for projecting the molded product 28 at this time was measured by a pressure sensor 25 installed on the ejector plate 24 to obtain a release force (unit: kgf). The value of the release force was recorded by a release force recorder 27.

The box-shaped molding cavity 22 has an inner wall on which a molded product 28 having a rectangular parallelepiped shape (bottomed container shape) having a thickness of 2 mm, a width of 32 mm, a depth of 40 mm, and a height of 21 mm can be formed. And one having a surface corresponding to the bottom side of the molded product 28 opened. Further, using an injection molding machine (trade name “SE-50D” manufactured by Sumitomo Heavy Industries, Ltd.), the mold surface temperature is 80 ° C., the polyamide resin composition temperature is 260 ° C. (however, in Comparative Example 1 is 280 ° C.), The injection conditions were set such that the screw advance speed was 100 mm / second, the holding pressure was 40 MPa, the injection time was 5 seconds, the cooling time was 20 seconds, and the molding cycle was 30 seconds. Each polyamide resin composition was continuously molded until the release force was stabilized, and the average release force was determined by averaging the release forces of 10 shots after the release force was stabilized. The smaller the average mold release force, the better the mold release property and the better the high cycle moldability.

(Manufacture of polyamide resin)
(Production Example 1)
15 kg of an aqueous solution containing an equimolar salt of hexamethylenediamine and sebacic acid as a polymerization component in an amount corresponding to 50% by mass as a polyamide resin was prepared. Next, the aqueous solution was charged into a 40 liter autoclave having a stirring device and having a discharge nozzle at the bottom, and the aqueous solution was sufficiently stirred at a temperature of 50 ° C. Next, after the inside of the autoclave was sufficiently substituted with nitrogen, the temperature inside the autoclave was increased from 50 ° C. to about 270 ° C. while stirring the aqueous solution. At this 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. Further, the polymerization time was adjusted so that the relative viscosity of the polyamide resin became the target relative viscosity. After the polymerization in the autoclave was completed, the polyamide resin was sent out in a strand form from the lower nozzle, and after water cooling and cutting, pellet-shaped polyhexamethylene sebacamide (polyamide 610) was obtained. This polyamide resin was vacuum dried at 80 ° C. for 24 hours. When the relative viscosity (ηr) of the polyamide resin was measured as described above, it was 2.50.

(Production Example 2)
Four types of pelletized polyhexamethylene dodeca having different relative viscosities were prepared in the same manner as in Production Example 1 except that an equimolar salt of hexamethylenediamine and dodecanedioic acid was used instead of the above-described polymerization component. An amide (polyamide 612) was obtained. These polyamide resins were vacuum dried at 80 ° C. for 24 hours. When the relative viscosity (ηr) of the polyamide resin was measured as described above, it was 1.85, 2.15, 3.20, and 3.75, respectively.

(Production Example 3)
A pellet-shaped polyhexamethylene adipamide (polyamide 66) was obtained in the same manner as in Production Example 1 except that an equimolar salt of hexamethylenediamine and adipic acid was used in place of the above-described polymerization component. . This polyamide resin was vacuum dried at 80 ° C. for 24 hours. When the relative viscosity (ηr) of the polyamide resin was measured as described above, it was 2.30.

In addition, as the boron nitride of the component (B), a commercial product having a powder average particle diameter of 2.5 μm measured as described above (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “DENCABORON NITRIDE SP-2”) Prepared. As the calcined kaolin of component (C), a commercial product (trade name, manufactured by Hayashi Kasei Co., Ltd.) having an average particle diameter of 1.5 μm measured as described above and surface-treated with γ-aminopropyltriethoxysilane. “TRANSLINK 445”) was prepared.

As a component other than the polyamide resin, boron nitride and calcined kaolin, commercially available talc having a powder average particle diameter of 4.0 μm measured as described above (trade name “Microace L-1” manufactured by Nippon Talc Co., Ltd.) Similarly, a commercially available wollastonite (trade name “Nyyard 325” manufactured by Hayashi Kasei Co., Ltd.) having an average particle diameter of 10 μm was prepared.

Example 1
(B) Boron nitride is 0.1 parts by mass and (C) calcined kaolin is 5.5 parts by mass with respect to 100 parts by mass of the pellet-like polyamide resin obtained in Production Example 1 above. Mix to obtain a mixture. The mixture was put into a twin screw extruder (trade name “ZSK26MC” manufactured by Coperion Co., Ltd.) and melt kneaded at 270 ° C. to obtain a polyamide resin composition. Various physical properties and characteristics of the obtained polyamide resin composition were evaluated as described above. Table 1 shows the composition and evaluation results of the polyamide resin composition. In the table, “PA” in the type of polyamide resin refers to “polyamide”.

(Example 2)
(B) 0.1 part by mass of boron nitride and (C) calcined kaolin are 5.5 parts with respect to 100 parts by mass of the pellet-like polyamide resin having a relative viscosity of 2.15 obtained in Production Example 2 above. They were mixed so that it might become a mass part, and the mixture was obtained. The mixture was put into a twin screw extruder (trade name “ZSK26MC” manufactured by Coperion Co., Ltd.) and melt kneaded at 250 ° C. to obtain a polyamide resin composition. Various physical properties and characteristics of the obtained polyamide resin composition were evaluated as described above. Table 1 shows the composition and evaluation results of the polyamide resin composition.

(Comparative Example 1)
With respect to 100 parts by mass of the pellet-like polyamide resin obtained in Production Example 3 above, (B) boron nitride is 0.1 parts by mass, and (C) calcined kaolin is 5.5 parts by mass. Mix to obtain a mixture. The mixture was put into a twin screw extruder (trade name “ZSK26MC” manufactured by Coperion Co., Ltd.) and melt kneaded at 280 ° C. to obtain a polyamide resin composition. Various physical properties and characteristics of the obtained polyamide resin composition were evaluated as described above. Table 1 shows the composition and evaluation results of the polyamide resin composition. From this evaluation result, it was confirmed that, due to the influence of 3% by mass of calcium chloride aqueous solution, the Izod impact value decreased after the chemical resistance test, the operating pressure of the battery gasket decreased significantly, and the battery leaked from the alkaline battery. It was.

(Comparative Example 2)
A polyamide resin composition was obtained in the same manner as in Example 2 except that talc was used instead of boron nitride. Various physical properties and characteristics of the obtained polyamide resin composition were evaluated as described above. Table 1 shows the composition and evaluation results of the polyamide resin composition. From this evaluation result, it is recognized that after the chemical resistance test, the Izod impact value is remarkably increased and the releasability is lowered due to the influence of the 3% by mass calcium chloride aqueous solution, which indicates a tendency to deteriorate the moldability. . In addition, leakage from alkaline batteries was observed. This is probably because the battery gasket was too soft and deformed because the Izod impact value after the chemical resistance test was high.

(Comparative Example 3)
A polyamide resin composition was obtained in the same manner as in Example 2 except that wollastonite was used instead of calcined kaolin. Various physical properties and characteristics of the obtained polyamide resin composition were evaluated as described above. Table 1 shows the composition and evaluation results of the polyamide resin composition. From this evaluation result, it was confirmed that the Izod impact value was remarkably lowered after the chemical resistance test due to the influence of 3% by mass of calcium chloride aqueous solution, and leaked from the alkaline battery.

(Comparative Example 4)
A polyamide resin composition was obtained in the same manner as in Example 2 except that boron nitride was not added. Various physical properties and characteristics of the obtained polyamide resin composition were evaluated as described above. Table 1 shows the composition and evaluation results of the polyamide resin composition. From this evaluation result, it was recognized that, due to the influence of 3 mass% calcium chloride aqueous solution, after the chemical resistance test, the Izod impact value was remarkably increased, the releasability was remarkably decreased, and the liquid was leaked from the alkaline battery.

(Example 3)
(B) 0.06 parts by mass of boron nitride and (C) 10 parts by mass of calcined kaolin with respect to 100 parts by mass of the pellet-like polyamide resin having a relative viscosity of 1.85 obtained in Production Example 2 above. They were mixed to obtain a mixture. The mixture was put into a twin screw extruder (trade name “ZSK26MC” manufactured by Coperion Co., Ltd.) and melt kneaded at 250 ° C. to obtain a polyamide resin composition. Various physical properties and characteristics of the obtained polyamide resin composition were evaluated as described above. Table 2 shows the composition and evaluation results of the polyamide resin composition.

Example 4
A polyamide resin composition was obtained in the same manner as in Example 3 except that a pellet-like polyamide resin having a relative viscosity of 3.20 obtained in Production Example 2 was used instead of the polyamide resin described above. Various physical properties and characteristics of the obtained polyamide resin composition were evaluated as described above. Table 2 shows the composition and evaluation results of the polyamide resin composition.

(Example 5)
A polyamide resin composition was obtained in the same manner as in Example 3 except that a pellet-like polyamide resin having a relative viscosity of 3.75 obtained in Production Example 2 was used instead of the polyamide resin described above. Various physical properties and characteristics of the obtained polyamide resin composition were evaluated as described above. Table 2 shows the composition and evaluation results of the polyamide resin composition.

(Example 6)
Instead of the polyamide resin described above, a pellet-like polyamide resin having a relative viscosity of 2.15 obtained in Production Example 2 was used, and the boron nitride content was changed from 0.06 parts by mass to 0.01 parts by mass. A polyamide resin composition was obtained in the same manner as in Example 3 except that the content ratio of the calcined kaolin was changed from 10 parts by mass to 1.8 parts by mass. Various physical properties and characteristics of the obtained polyamide resin composition were evaluated as described above. Table 2 shows the composition and evaluation results of the polyamide resin composition.

(Example 7)
A polyamide resin was obtained in the same manner as in Example 6 except that the content ratio of boron nitride was changed from 0.01 parts by mass to 0.08 parts by mass, and the content ratio of calcined kaolin was changed from 1.8 parts by mass to 15 parts by mass. A composition was obtained. Various physical properties and characteristics of the obtained polyamide resin composition were evaluated as described above. Table 2 shows the composition and evaluation results of the polyamide resin composition.

(Example 8)
Except for changing the content ratio of boron nitride from 0.01 parts by mass to 2.5 parts by mass, and changing the content ratio of calcined kaolin from 1.8 parts by mass to 7.5 parts by mass, the same as in Example 6, A polyamide resin composition was obtained. Various physical properties and characteristics of the obtained polyamide resin composition were evaluated as described above. Table 2 shows the composition and evaluation results of the polyamide resin composition.

The industrial applicability of the present invention is expected to be used for various parts of automobiles, electronic and electrical products, industrial machinery, particularly battery gaskets.

Claims

(A) a polyamide resin comprising polyhexamethylene sebacamide and / or polyhexamethylene dodecamide;
(B) boron nitride;
(C) calcined kaolin;
A battery gasket obtained by molding a polyamide resin composition comprising
The polyamide resin composition contains 0.0001 to 3 parts by mass of the component (B) and 0.01 to 20 parts by mass of the component (C) with respect to 100 parts by mass of the component (A). The battery gasket according to claim 1.
3. The battery according to claim 1, wherein the polyamide resin composition contains (D) 1 to 20 parts by mass of a polyamide resin different from the component (A) with respect to 100 parts by mass of the component (A). Gasket.
The battery gasket according to any one of claims 1 to 3, wherein the powder (B) has an average powder particle size of 10 µm or less.
The battery gasket according to any one of claims 1 to 4, wherein the polyamide resin composition contains 100 to 20000 parts by mass of the component (C) with respect to 100 parts by mass of the component (B).
An alkaline dry battery comprising the battery gasket according to any one of claims 1 to 5.