JP2003331797A - Battery case - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery case with a more excellent barrier property than a conventional one and capable of elongating a battery life. <P>SOLUTION: The case consists of a resin composition of which (a) polyphenylene sulfide and (b) an olefin resin occupy 80 weight percent of the total with a content of (b) of 0 to 100 weight parts to 100 weight parts of (a). The resin composition has a vapor permeation volume of 0.6 g/m<SP>2</SP>×24 H or less as measured at a temperature of 40°C in accordance with the JIS K-7129B method by a test specimen of a thickness of 2 mm, and a hydrogen permeability coefficient of 4.0×10<SP>-15</SP>mol×m/m<SP>2</SP>×s×Pa or less as measured at a temperature of 40°C in accordance with the JIS K-7126A method by a test specimen of a thickness of 2 mm. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a battery case having excellent barrier properties.

[0002]

2. Description of the Related Art For example, a battery case, which is a case of a battery mounted on an automobile, is not limited to a metal case, but a resin case is often produced. Among the resin-made battery cases, it is lightweight and has excellent chemical resistance and heat resistance.
"P". ) / Polyphenylene ether (hereinafter,
It describes as "PPE." ) Composite materials are in mass production.

[0003]

[Problems to be Solved] By the way, as a characteristic required for a resin battery case, in addition to the above-mentioned chemical resistance, it is required to have an excellent barrier property for suppressing permeation of water and the like. However, the above PP / PPE composite material does not have sufficient barrier properties, which may shorten the battery life. For example, when water or hydrogen permeates, the concentration of the electrolytic solution changes, which shortens the battery life.

The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide a battery case which is superior in barrier property to the conventional one and can prolong the battery life.

[0005]

The first invention is such that (a) a polyphenylene sulfide resin and (b) an olefin resin account for 80% by weight or more of the entire composition, and the content of (b) is
(A) A resin composition in an amount of 0 to 100 parts by weight relative to 100 parts by weight, the resin composition having a thickness of 2 mm and a temperature of 40 ° C. according to JIS K-7129B method.
Moisture permeation measured at 0.6g / m ² · 24H
It is the following, and it is JIS by the test piece with a thickness of 2 mm.
The hydrogen permeation coefficient measured according to the K-7126A method at a temperature of 40 ° C. is 4.0 × 10 ⁻¹⁵ mol · m / m ² · s ·
It is in the battery case characterized by being Pa or less (Claim 1).

The battery case of the present invention comprises a resin composition having the above polyphenylene sulfide resin (hereinafter referred to as PPS resin) and an olefin resin in the above-mentioned specific proportions. The olefin resin is an arbitrary component resin as shown in the above content. The above resin composition constituting the battery case of the present invention can bring out the characteristics of suppressing both the water permeation amount and the hydrogen permeation coefficient as described above, and can improve the barrier property as compared with the conventional case. Therefore, if a battery case made of this resin composition is used, it is possible to suppress changes in the concentration of the electrolytic solution, etc., and extend the battery life.

When the above resin composition contains an olefin resin, it can exhibit excellent flexibility, impact resistance, heat resistance, thermal stability, chemical resistance and oil resistance. . In addition, the above resin composition in which the above resin composition contains an olefin resin also has excellent welding characteristics. Therefore, it is possible to construct the battery case by welding a plurality of members made of the resin composition.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the PPS resin and the olefin resin account for 80% by weight or more of the entire composition of the resin composition constituting the battery case of the present invention. If the total content of both is less than 80%, high heat resistance, thermal stability, and chemical resistance may be impaired. Therefore, it is more preferable that the total content of both is 90% by weight or more.

Further, it is possible to add a resin other than the olefin copolymer to the above resin composition within a range not impairing the effects of the present invention. For example, flexibility and impact resistance can be further improved by adding a small amount of a highly flexible thermoplastic resin. However, if this amount is 20% by weight or more of the entire resin composition, the high heat resistance, thermal stability and chemical resistance inherent to the PPS resin are impaired, which is not preferable, and addition of 10% by weight or less is particularly preferable.

The content ratio of the PPS resin and the olefin resin is 0 to 100 parts by weight based on 100 parts by weight of the PPS resin. This makes it possible to obtain a resin composition having excellent barrier properties. Further, by containing an olefin resin, it is possible to obtain a battery case having excellent welding characteristics, flexibility and impact resistance. On the other hand, if it exceeds 100 parts by weight, not only the heat resistance, heat stability, chemical resistance, and oil resistance inherent to the PPS resin are impaired, but also the thickening at the time of melt-kneading becomes large and the injection moldability is impaired. This is not preferable because it tends to occur.

Further, the above (b) in the above resin composition
The content of the olefin resin is preferably 10 to 100 parts by weight with respect to 100 parts by weight of (a) (claim 2). By containing 10 parts by weight or more of the olefin resin, the effects of improving the welding characteristics, flexibility and impact resistance can be further enhanced. More preferably, the blending ratio of the olefin resin is 15 to 70 parts by weight with respect to 100 parts by weight of the PPS resin. This makes it possible to further improve the flexibility and welding characteristics while maintaining the original characteristics of the PPS resin.

Further, the above resin composition, as described above,
The water permeation rate measured according to the JIS K-7129B method with a 2 mm thick test piece is 0.6 g / m ² · 24H or less, and the JIS K-
Hydrogen permeation coefficient measured according to the 7126A method is 4.0 ×
It is 10 ⁻¹⁵ mol · m / m ² · s · Pa or less. By having these two characteristics, the barrier property required for the battery case can be greatly improved. And the battery case constituted by using the resin composition satisfying these characteristics can extend the battery life in various batteries such as a lead battery, a nickel hydrogen battery, a nickel cadmium battery and a lithium battery.

On the other hand, the water permeation rate is 0.6 g / m ² ·
When it exceeds 24H, or when the hydrogen permeability coefficient is 4.
If it exceeds 0 × 10 ⁻¹⁵ mol · m / m ² · s · Pa, the concentration of the electrolyte may change due to the permeation of water or hydrogen, and the battery life may not be extended. . The moisture permeation rate is more preferable as it approaches 0 g / m ² · 24H, and the hydrogen permeation coefficient is 0 mol · m / m.
^The closer to ² · s · Pa, the better.

Now, the resin composition resin used in the battery case will be described in more detail below. (A) Polyphenylene sulfide resin (PPS resin) The PPS resin contained in the resin composition is a polymer containing a repeating unit represented by the following structural formula.

[0015]

[Chemical 1]

From the viewpoint of heat resistance, the PPS resin is preferably a polymer containing 70 mol% or more, especially 90 mol% or more of the repeating unit. The PPS resin can comprise less than 30 mol% of its repeating unit with a repeating unit having the following structural formula.

[0017]

[Chemical 2]

[0018]

[Chemical 3]

[0019]

[Chemical 4]

[0020]

[Chemical 5]

[0021]

[Chemical 6]

[0022]

[Chemical 7]

[0023]

[Chemical 8]

As the PPS resin, Japanese Patent Publication No.
A polymer having a relatively small molecular weight obtained by the method disclosed in JP-A-5-3368, or JP-B-52
There is a substantially linear polymer having a relatively high molecular weight and the like obtained by the method disclosed in JP-A-12240.

The polymer obtained by the method described in the above Japanese Patent Publication No. 45-3368 is heated by heating in an oxygen atmosphere after polymerization or by adding a crosslinking agent such as peroxide to heat. It is also possible to use it after increasing the degree of polymerization. In the present invention, a PPS resin obtained by any method can be used, but the above-mentioned special characteristics are obtained because the effect of the present invention is remarkable and the toughness, flexibility and impact resistance of the PPS resin itself are excellent. Kosho 52
A substantially linear polymer having a relatively high molecular weight is preferably used by the production method typified by JP-12240.

The PPS resin used in the present invention is preferably one which has been subjected to i) acid treatment, ii) hot water treatment or iii) washing with an organic solvent after being produced through the above-mentioned polymerization step.

I) Acid treatment The acid used for the acid treatment is not particularly limited as long as it has no action of decomposing the PPS resin, and acetic acid, hydrochloric acid, sulfuric acid,
Phosphoric acid, silicic acid, carbonic acid, propyl acid and the like can be mentioned. Among them, acetic acid and hydrochloric acid are more preferably used, but nitric acid and the like that decompose and deteriorate the PPS resin are not preferable. As a method of acid treatment, there is a method of immersing the PPS resin in an acid or an aqueous solution of an acid, and it is also possible to appropriately stir or heat if necessary. For example, in the case of using acetic acid, the pH of the aqueous solution is heated to 80 to 90 ° C.
A sufficient effect can be obtained by immersing the PS resin powder and stirring for 30 minutes. The acid-treated PPS resin needs to be washed several times with water or warm water in order to physically remove residual acid or salt. The water used for washing is preferably distilled water or deionized water in the sense that the effect of preferable chemical modification of the PPS resin by acid treatment is not impaired.

Ii) Hot water treatment In hot water treatment of PPS resin, the temperature of hot water is set to 10
It is important that the temperature is 0 ° C. or higher, more preferably 120 ° C. or higher, further preferably 150 ° C. or higher, particularly preferably 170 ° C. or higher. If the temperature of hot water is less than 100 ° C, P
It is not preferable since the effect of preferable chemical modification of the PS resin is small. The water to be used is preferably distilled water or deionized water in order to exert the preferable effect of chemically modifying the PPS resin by the hot water treatment. The operation of hot water treatment is usually performed by pouring a predetermined amount of PPS resin into a predetermined amount of water and heating and stirring in a pressure vessel.
As for the ratio of PPS resin and water, it is preferable that there is more water,
Usually, a ratio of 200 g or less of PPS resin to 1 liter of water is selected. The hot water treatment atmosphere should be an inert atmosphere. This is to avoid the decomposition of the terminal group, which is not preferable. The PPS resin that has been subjected to this hot water treatment operation is preferably washed several times with warm water to remove residual components.

Iii) Washing with organic solvent The organic solvent used for washing the PPS resin is not particularly limited as long as it does not have an action of decomposing the PPS resin, and for example, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, Nitrogen-containing polar solvents such as 1,3-dimethylimidazolidinone, hexamethylphosphorus amide, piperazinones, sulfoxide-sulfone solvents such as dimethyl sulfoxide, dimethyl sulfone and sulfolane, ketones such as acetone, methyl ethyl ketone, diethyl ketone, acetophenone -Based solvent, ether-based solvent such as dimethyl ether, dipropyl ether, dioxane, tetrahydrofuran, chloroform, methylene chloride, trichloroethylene, ethylene dichloride, perchlorethylene, monochloroethane , Dichloroethane,
Halogen-based solvents such as tetrachloroethane, perchlorethane, chlorobenzene, alcohol-phenolic solvents such as methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, polyethylene glycol, polypropylene glycol, etc. benzene,
Examples thereof include aromatic hydrocarbon solvents such as toluene and xylene. Among these organic solvents, it is particularly preferable to use N-methylpyrrolidone, acetone, dimethylformamide, chloroform and the like. In addition, these organic solvents are used alone or in a mixture of two or more kinds.

As a method of washing with an organic solvent, there is a method of immersing a PPS resin in an organic solvent.
It is also possible to appropriately stir or heat if necessary. The washing temperature when washing the PPS resin with an organic solvent is not particularly limited, and any temperature from normal temperature to 300 ° C. can be selected. The higher the cleaning temperature is, the higher the cleaning efficiency tends to be. However, normally, the cleaning temperature of room temperature to 150 ° C. is sufficient to obtain the effect. It is also possible to wash under pressure at a temperature above the boiling point of the organic solvent in a pressure vessel. There is also no particular limitation on the cleaning time. Although it depends on the washing conditions, in the case of batch type washing, a sufficient effect is usually obtained by washing for 5 minutes or more. It is also possible to wash in a continuous manner.

The PPS resin produced by the polymerization may be washed with an organic solvent, but in order to further exert the effect of the present invention, it is preferably combined with water washing or warm water washing. When a high boiling water-soluble organic solvent such as N-methylpyrrolidone is used, after washing with an organic solvent,
Washing with water or warm water is preferable because the residual organic solvent can be easily removed. Water used for these washings is preferably distilled water or deionized water.

The melt viscosity of the PPS resin used in the present invention is a melt flow rate (temperature 315.5 ° C., measured according to ASTM-D1238, in order to highly balance the flexibility and impact resistance of the resulting composition. The load 0.49 MPa) is preferably 250 g / 10 min or less, and more preferably 150 g / 10 min or less.

(B) Olefin-based resin The olefin-based resin used in the present invention is a polymer obtained by (co) polymerizing an olefin, and specifically, an olefin-based (co) polymer, and an epoxy group, an acid An olefin-based (co) polymer (modified olefin-based (co) polymer) obtained by introducing a monomer component having a functional group such as an anhydride group or a carboxylic acid metal complex (hereinafter abbreviated as a functional group-containing component)
Polymer) and the like. In the present invention, the olefin resin may be used alone or in combination of two or more.

The olefin (co) polymer is obtained by polymerizing α-olefins such as ethylene, propylene, butene-1, pentene-1,4-methylpentene-1, isobutylene or a combination of two or more kinds ( Co) polymer, α
-Copolymerization of olefins with α, β-unsaturated carboxylic acids such as acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate and their alkyl esters Examples include coalescing. Preferable specific examples of the olefin (co) polymer include polyethylene,
Polypropylene, ethylene / propylene copolymer, ethylene / butene-1 copolymer, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / butyl acrylate copolymer, ethylene / methyl methacrylate Examples thereof include copolymers, ethylene / ethyl methacrylate copolymers, ethylene / butyl methacrylate copolymers, and the like.

In the olefinic copolymer, 40% by weight or less, and other copolymerizable unsaturated monomers such as vinyl ether, vinyl acetate and vinyl propionate within a range not impairing the object of the present invention. , Acrylonitrile, styrene, etc. may be copolymerized.

Examples of the functional group-containing component for introducing a monomer component having a functional group such as an epoxy group, an acid anhydride group and a carboxylic acid metal complex into the above-mentioned olefin (co) polymer include maleic anhydride. Monomers containing acid anhydride groups such as acid, itaconic anhydride, citraconic anhydride, endobicyclo- (2,2,1) -5-heptene-2,3-dicarboxylic acid anhydride, glycidyl acrylate, Examples thereof include monomers containing an epoxy group such as glycidyl methacrylate, glycidyl ethacrylic acid, glycidyl itaconate, and glycidyl citracone, and monomers containing a metal carboxylate complex.

The method of introducing these functional group-containing components is not particularly limited, and methods such as copolymerization or graft introduction to an olefin polymer using a radical initiator can be used. The introduced amount of the monomer component containing a functional group is 0.001 to the whole olefin (co) polymer.
Suitably it is in the range of 40 mol%, preferably 0.01 to 35 mol%.

An olefin (co) polymer obtained by introducing a monomer component having a functional group such as an epoxy group, an acid anhydride group or a carboxylic acid metal complex into the olefin (co) polymer particularly useful in the present invention. As α-olefin and α, β-
Olefin-based (co) polymer containing glycidyl ester of unsaturated carboxylic acid as an essential copolymerization component, olefin-based (co) polymer containing α-olefin and a monomer containing an acid anhydride group as an essential copolymerization component And an olefin-based copolymer containing an α-olefin and a carboxylic acid metal complex as an essential copolymerization component. Further, these copolymers further include α, β-unsaturated carboxylic acids such as acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, and butyl methacrylate, and It is also possible to copolymerize the alkyl ester or the like.

In the present invention, it is particularly preferable to use an olefin-based copolymer containing an α-olefin and a glycidyl ester of an α, β-unsaturated carboxylic acid as an essential component. % And α, β
An olefin-based copolymer containing 1 to 40% by weight of a glycidyl ester of an unsaturated carboxylic acid as an essential copolymerization component is preferable. As the glycidyl ester of α, β-unsaturated carboxylic acid, a compound represented by the following general formula can be used. In the formula, R represents a hydrogen atom or a lower alkyl group.

[0040]

[Chemical 9]

Specific examples of the glycidyl ester of α, β-unsaturated carboxylic acid include glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylic acid and the like. Of these, glycidyl methacrylate is preferably used. A specific example of the olefin-based copolymer having glycidyl ester of α-olefin and α, β-unsaturated carboxylic acid as an essential copolymerization component is ethylene / propylene-g-glycidyl methacrylate copolymer (“g” is Represents a graft, the same applies hereinafter), ethylene / butene-1-
g-glycidyl methacrylate copolymer, ethylene / glycidyl acrylate copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / methyl acrylate / glycidyl methacrylate copolymer, ethylene / methyl methacrylate / glycidyl methacrylate copolymer Polymers may be mentioned. Among them, ethylene / glycidyl methacrylate copolymer, ethylene / methyl acrylate / glycidyl methacrylate copolymer, ethylene / methyl methacrylate / glycidyl methacrylate copolymer are preferably used.

As described above, the resin composition used in the battery case of the present invention is (a) PPS resin and (b) in order not to impair the high heat resistance, thermal stability and chemical resistance inherent to PPS resin. ) It is necessary that the total amount of the olefin resin is 80% by weight or more, and more preferably 90% by weight or more of the total composition.

In addition to the (a) PPS resin and (b) olefin resin, a resin other than the olefin copolymer may be added to the above resin composition within a range that does not impair the effects of the present invention. It is possible. For example, flexibility and impact resistance can be further improved by adding a small amount of a highly flexible thermoplastic resin.

Specific examples of the thermoplastic resin include polyamide resin, polybutylene terephthalate resin, modified polyphenylene ether resin, polysulfone resin, polyallyl sulfone resin, polyketone resin, polyetherimide resin, polyarylate resin, liquid crystal polymer, Examples thereof include polyether sulfone resin, polyether ketone resin, polythioether ketone resin, polyether ether ketone resin, polyimide resin, polyamideimide resin, and tetrafluoropolyethylene resin. The following compounds can be added for the purpose of modification.
Coupling agents such as isocyanate compounds, organic silane compounds, organic titanate compounds, organic borane compounds, epoxy compounds, polyalkylene oxide oligomer compounds, thioether compounds, ester compounds, plasticizers of organic phosphorus compounds, etc. , Talc, kaolin, organophosphorus compounds, crystal nucleating agents such as polyether ether ketone, polyolefins such as polyethylene and polypropylene, montanic acid waxes, metallic soaps such as lithium stearate and aluminum stearate, ethylenediamine / stearic acid / sebacic acid Heavy compounds, release agents such as silicone compounds, anti-coloring agents such as hypophosphite,
In addition, usual additives such as a lubricant, an anti-UV agent, a coloring agent, a flame retardant, and a foaming agent can be added. When the above compound exceeds 20% by weight of the whole resin composition, PP
It is not preferable because the original characteristics of S resin are impaired.
It is preferable to add less than 1% by weight, more preferably less than 1% by weight.

The above resin composition is kneaded by a kneader or the like. As a typical example of the kneader, a method of supplying to a conventionally known melt kneader such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader and a mixing roll and kneading at a temperature of 280 to 380 ° C. can be mentioned. However, in order to control the dispersion form of the olefin-based copolymer as described above, it is preferable to make the shearing force relatively strong.

Specifically, a method of using a twin-screw extruder and kneading so that the resin temperature during mixing is 320 to 380 ° C. can be preferably used. At this time, the order of mixing the raw materials is not particularly limited, and a method of mixing all the raw materials and then melt-kneading by the above method, a method of mixing some raw materials and then melt-kneading by the above method, and further mixing the remaining raw materials Any method such as a method of melt-kneading or a method of mixing a part of raw materials and then mixing the remaining raw materials by using a side feeder during melt-kneading with a single-screw or twin-screw extruder may be used. In addition, as for the small amount additive component, it is also possible to knead the other components by the above-mentioned method or the like to form pellets, and then add the components before molding and use them for molding. The resin composition used in the battery case of the present invention is a resin composition in which the compound type and the amount of the (a) PPS resin and (b) the olefin resin are adjusted so as to have the above-mentioned physical property values.

The battery case may be integrally molded by injection molding, or may be manufactured by welding a plurality of molded pieces. When the battery case is manufactured by welding, as the welding method, for example, a hot plate welding method, a laser welding method, a vibration welding method, or the like can be adopted.

Next, the resin composition preferably has a tensile elongation at break of 35% or more measured according to ASTM-D638 under the conditions of a temperature of 23 ° C. and a relative humidity of 50% (claim 3). The tensile elongation at break of the resin composition is 35
When it is at least%, the pressure resistance of the battery case can be sufficiently increased. On the other hand, if it is less than 35%, the welding characteristics may deteriorate when the welding is performed.

The battery case is constructed by welding a plurality of members made of the resin composition. The resin composition including the welded portion has a tensile elongation at break of 23 ° C. and a relative humidity of 50%. It is preferable that the value measured according to ASTM-D638 is 20% or more under the condition of (Claim 4).
The term "tensile rupture elongation" as used herein means the tensile rupture elongation of the entire resin including the welded portion, if any. In the case where there is a welded portion, the tensile test shows yielding, and then cohesive failure at the weld interface or fracture at a portion other than the welded portion (ductile fracture). On the other hand, when the tensile elongation at break is less than 20%, interface fracture often occurs at the welded portion, and it cannot be said that ductile fracture occurs.

Further, the above resin composition is ASTM-D2.
Izod impact strength measured according to 56 is 500 J /
It is preferably m or more (claim 5). As a result, the effects of the present invention can be exhibited, and the impact strength is further improved. On the other hand, the Izod impact strength is 500 J /
If it is less than m, the impact strength may decrease. Here, the above-mentioned eye dot impact strength refers to notched Izod impact strength.

The resin composition has a tensile elongation at break of 3 or less.
5% or more and the above Izod impact strength is 500
It is more preferably J / m or more. Since the battery case formed of such a resin composition has both ductility and strength, when it has a welded portion, it is possible to maintain the strength at the same level as the strength of the general portion and suppress the fracture at the welded portion. You can

The (b) olefin resin is α
An olefin-based copolymer obtained by copolymerizing 60 to 99% by weight of an olefin and 1 to 40% by weight of a glycidyl ester of an α, β-unsaturated carboxylic acid as essential components is preferable (claim 6). As a result, the effect of the present invention can be obtained, and in addition, the dispersibility of the olefin resin is improved and a sufficient flexibility-imparting effect can be obtained. On the other hand, when the amount of α-olefin is less than 60% by weight, or when the amount of glycidyl ester of α, β-unsaturated carboxylic acid exceeds 40% by weight, gelation may occur during melt kneading with the PPS resin. When the α-olefin content exceeds 99% by weight,
Alternatively, when the glycidyl ester of α, β-unsaturated carboxylic acid is less than 1% by weight, there are too few functional groups that react with the PPS resin, the dispersibility is poor, and a sufficient flexibility-imparting effect may not be obtained. is there.

Particularly, 97-70% by weight of α-olefin
And the glycidyl ester of α, β-unsaturated carboxylic acid is preferably 3 to 30% by weight. As a specific example, a copolymer containing ethylene / glycidyl methacrylate in a proportion of 70 to 97% by weight / 3 to 30% by weight is preferably used.

Further, an olefin-based (co) compound containing an α-olefin and a monomer containing an acid anhydride group as an essential copolymerization component
Specific examples of the polymer include ethylene / propylene-g-
Maleic anhydride copolymer, ethylene / butene-1-g-
Maleic anhydride copolymer, ethylene / methyl acrylate-g-maleic anhydride copolymer, ethylene / ethyl acrylate-g-maleic anhydride copolymer, ethylene / methyl methacrylate-g-maleic anhydride copolymer And ethylene / ethyl methacrylate-g-maleic anhydride copolymer. Specific examples of the olefin-based copolymer containing α-olefin and a carboxylic acid metal complex as an essential copolymerization component include ethylene / methacrylic acid. Examples thereof include a zinc complex of a copolymer, a magnesium complex of an ethylene / methacrylic acid copolymer, and a sodium complex of an ethylene / methacrylic acid copolymer.

In the present invention, as described above, as the component (b), 60 to 99% by weight of α-olefin and α, β
-It is preferable to use an olefin-based copolymer having 1 to 40% by weight of a glycidyl ester of an unsaturated carboxylic acid as an essential copolymerization component. Among them, such a copolymer, an epoxy group, an acid anhydride group and a carboxylic acid are preferably used. It is preferable to use together an olefin (co) polymer having no functional group of the metal complex. For example, ethylene / butene-1 copolymer and ethylene / propylene copolymer are preferably used. As the olefin-based (co) polymer having no such functional group, one having a relatively low melt flow rate (MFR) is preferable since it has high flexibility, and particularly 3
It is preferably g / 10 min (ASTM-D1238, 190 ° C., load 0.21 MPa) or less.

When the olefin-based (co) polymer having a functional group and the olefin-based (co) polymer having no functional group are used together as the component (b), the combined ratio is the sum of both. On the other hand, it is preferable that the olefin (co) polymer having a functional group is 10 to 40% by weight, and the olefin (co) polymer having no functional group is 90 to 60% by weight.

It is preferable that the olefin resin (b) is dispersed in the resin composition in the form of particles having an average particle diameter of 0.5 μm or less (claim 7). As a result, the tensile elongation at break and Izod impact strength are improved, and the tensile elongation at break of the battery case is increased. Further, in order to further improve these physical properties, the (b) olefin resin is preferably dispersed in the resin composition in the form of particles having an average particle diameter of 0.3 μm or less.

The resin composition further comprises (c) 100 parts by weight of the polyphenylene sulfide resin, and (c) one or more antioxidants selected from the group consisting of phenol series, thioether series and phosphorus series. It is preferable to contain 0.01 to 5 parts by weight (claim 8). As a result, in addition to the thermal stability during molding of the battery case, the thermal stability during welding is also improved, so that the welding characteristics are improved. The blending amount of such an antioxidant is preferably 0.01 parts by weight or more from the viewpoint of the heat resistance improving effect, and is preferably 5 parts by weight or less from the viewpoint of the gas component generated during molding. In addition, it is preferable to use the phenol-based and phosphorus-based antioxidants in combination because the heat resistance and the thermal stability retention effect are particularly large.

As the phenolic antioxidant, a hindered phenolic compound is preferably used, and a specific example thereof is triethylene glycol-bis [3-t-butyl- (5-methyl-4-hydroxyphenyl) propionate]. , N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamide),
Tetrakis [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, pentaerythrityl tetrakis [3- (3', 5'-
Di-t-butyl-4′-hydroxyphenyl) propionate], 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) -s-triazine-2,
4,6- (1H, 3H, 5H) -trione, 1,1,3
-Tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 4,4'-butylidenebis (3-
Methyl-6-t-butylphenol), n-octadecyl-3- (3,5-di-t-butyl-4-hydroxy-)
Phenyl) propionate, 3,9-bis [2- (3-
(3-t-Butyl-4-hydroxy-5-methylphenyl) propionyloxy) -1,1-dimethylethyl]
-2,4,8,10-Tetraoxaspiro [5,5] undecane, 1,3,5-trimethyl-2,4,6-tris- (3,5-di-t-butyl-4-hydroxybenzyl ) Benzene and the like.

Of these, the ester type polymer hindered phenol type is preferable, and specifically, tetrakis [methylene-3- (3 ', 5'-di-t-butyl-
4'-hydroxyphenyl) propionate] methane,
Pentaerythrityl tetrakis [3- (3 ', 5'-di-
t-butyl-4′-hydroxyphenyl) propionate], 3,9-bis [2- (3- (3-t-butyl-4)
-Hydroxy-5-methylphenyl) propionyloxy) -1,1-dimethylethyl] -2,4,8,10-
Tetraoxaspiro [5,5] undecane and the like are preferably used.

Next, as the thioether type antioxidant,
Tetrakis [methylene-3- (dodecylthio) propionate] methane, dilauryl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate and the like can be mentioned.

Next, as phosphorus antioxidants, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphite and bis (2,4-
Di-t-butylphenyl) pentaerythritol-di-
Phosphite, bis (2,4-di-cumylphenyl) pentaerythritol-di-phosphite, tris (2,2
4-di-t-butylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl) -4,4'-bisphenylene phosphite, di-stearyl pentaerythritol-di-phosphite, triphenylphosphite Examples include phyto, 3,5-di-butyl-4-hydroxybenzylphosphonate diethyl ester and the like.

Among these, in order to reduce the volatilization and decomposition of the antioxidant, those having a high melting point are preferable. Specifically, bis (2,6-di-t-butyl-4) is preferable.
-Methylphenyl) pentaerythritol-di-phosphite, bis (2,4-di-t-butylphenyl) pentaerythritol-di-phosphite, bis (2,4-)
Di-cumylphenyl) pentaerythritol-di-phosphite is preferably used.

[0064]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the description of these examples. In this example, 13 types of examples were prepared as the resin composition used in the battery case, and 2 types of comparative examples for comparison were prepared, and the characteristics were measured and evaluated. In the following examples, the material properties were measured by the following methods. The amount of water permeation and the hydrogen permeation coefficient were measured by the following methods as indicators of barrier properties. Also, MFR retention rate as an index of thermal stability and 80 as an index of heat resistance.
Oil resistance (weight increase rate) was measured by the following method as an index of ℃ flexural modulus and chemical resistance. Each test piece used to measure these material properties was injection molded (cylinder temperature 320 ° C,
It was produced at a mold temperature of 130 ° C.

[Moisture Permeation Amount] A test piece made of a square plate having a thickness of 2 mm prepared by injection molding was used, and JIS K-7 was used.
According to the 129B method, it was measured at a humidity of 90% RH (relative humidity) and a temperature of 40 ° C. [Hydrogen Permeability Coefficient] Using a test piece composed of a square plate having a thickness of 2 mm prepared by injection molding, it was measured at a humidity of 90% RH (relative humidity) and a temperature of 40 ° C. according to JIS K-7126A method.

[Average particle size of olefin resin] ASTM No. 1 dumbbell piece as a test piece was molded by the above-mentioned method, and a thin piece of 0.1 µm or less was cut from the center of the piece at -20 ° C to obtain a transmission electron. Arbitrary 10 when observed with a microscope
The maximum diameter and the minimum diameter of each of the 0 elastomer-dispersed parts were first measured to obtain an average value, and then the average value of the numbers was obtained. [Tensile breaking elongation] The tensile breaking elongation was measured according to ASTM-D638. [Izod impact strength] A test piece was prepared by injection molding, a notch was made, and a notched test piece was prepared. The notched Izod impact strength of this test piece was measured according to ASTM-D256.

[80 ° C. Flexural Modulus] ASTM-D790
According to the above, the measurement was performed at 80 ° C. [MFR retention rate, MF6
0 / MF5] Measurement temperature 315.5 ° C, load 0.49MP
a (5000 g), MFR (MF5) with a retention time of 5 minutes and MFR (MF60) with a retention time of 60 minutes were measured by the method according to ASTM-D1238-86.
The ratio of both (MF60 / MF5) was expressed by%. When the viscosity increases due to the retention, the MFR retention rate is low, and when the viscosity is low, the MFR retention rate is high. [Oil resistance] ASTM No. 1 dumbbell piece was injection-molded as a test piece and immersed in a refrigerating machine oil (JIS type 2, ISO56, Suniso SG manufactured by Nippon Sun Oil Co., Ltd.) at 100 ° C for 70 hours, and the weight change was measured. Is displayed as a percentage.

[Tensile Rupture Elongation of Resin Molded Body Having Welded Part] As shown in FIG. 1 (a), two molded pieces 2 having a half length of ASTM No. 1 dumbbell were molded. As shown in FIG. 1 (b), these two molded pieces 2 are welded by a hot plate welding machine (hot plate temperature 290 to 320 ° C., melting time 30 to 90 seconds) in an atmosphere at room temperature (23 ° C.), A resin molded body 100 having the welded portion 3 was produced. Then, the resin molded body 10
0 was subjected to a tensile test according to ASTM-D638. The pulling speed when pulling the resin molded body 100 is
It was set to 5 mm / min.

Two types of PPS resins were prepared by the following method. (1) Preparation of PPS-1 Sodium sulfide nonahydrate was added to an autoclave equipped with a stirrer.
005 kg (25 mol), sodium acetate 0.656 k
g (8 mol) and N-methyl-2-pyrrolidone (hereinafter N
5 kg (abbreviated as MP) was charged, the temperature was gradually raised to 205 ° C. while passing nitrogen, and 3.6 liters of water was distilled. Next, after cooling the reaction vessel to 180 ° C., 3.727 kg (25.35 mol) of 1,4-dichlorobenzene and NMP were added.
3.7 kg was added, the mixture was sealed under nitrogen, heated to 225 ° C. and reacted for 5 hours, then heated to 270 ° C. and reacted for 3 hours. After cooling, the reaction product was washed 5 times with warm water. Then 1
Approximately 1 when put into 10kg of NMP heated to 00 ℃
After stirring for a while, the mixture was filtered and washed with hot water several times. This was heated to 90 ° C. and the pH 4 acetic acid aqueous solution 2
After pouring into 5 liters and continuing stirring for about 1 hour, it is filtered, washed with ion exchanged water at about 90 ° C until the pH of the filtration reaches 7, and then dried under reduced pressure at 80 ° C for 24 hours to obtain MFR1.
00 (g / 10 min) of PPS-1 was obtained.

(2) Preparation of PPS-2 In an autoclave equipped with a stirrer, sodium sulfide nonahydrate 6.
005 kg (25 mol), sodium acetate 0.656 k
g (8 mol) and N-methyl-2-pyrrolidone (hereinafter N
5 kg (abbreviated as MP) was charged, the temperature was gradually raised to 205 ° C. while passing nitrogen, and 3.6 liters of water was distilled. Then, after cooling the reaction vessel to 180 ° C., 3.756 kg (25.55 mol) of 1,4-dichlorobenzene and NMP were added.
3.7 kg was added, the mixture was sealed under nitrogen, heated to 270 ° C., and reacted at 270 ° C. for 2.5 hours. After cooling, the reaction product was washed 5 times with warm water. Next, it was put into 10 kg of NMP heated to 100 ° C., and after stirring for about 1 hour, it was filtered and further washed with hot water several times. 90 ° C
Pour into 25 liters of pH 4 acetic acid aqueous solution heated to 1, and continue stirring for about 1 hour, then filter and wash with ion-exchanged water at about 90 ° C until the pH of filtration reaches 7, then at 80 ° C.
After drying under reduced pressure for 24 hours, MFR300 (g / 10mi
nPS of PPS-2 was obtained. In addition, MF of PPS-1, 2
R is measured temperature 315.5 ° C., load 0.49 MPa (5
000 g) and was measured by a method according to ASTM-D1238-86.

The following five types of olefin resins were prepared. (1) Olefin-1: ethylene / glycidyl methacrylate = 8/12 wt% copolymer (2) Olefin-2: ethylene / 1-butene copolymer Density 864 Kg / m3 MFR = 3.5 g / 10 min
(Load 0.21 MPa (2160 g), 190 ° C, AS
Method according to TM-D1238) (3) Olefin-3: ethylene / 1-butene copolymer Density 861 kg / m3 MFR = 0.5 g / 10 min
(Load 0.21 MPa (2160 g), 190 ° C, AS
Method according to TM-D1238) (4) Olefin-4: ethylene / propylene = 85 /
15 mol% Copolymer (5) Olefin-5: Polyethylene Density 955 Kg
/ M3 MFR = 0.03-0.07g / 10min
(Load 0.21 MPa (2160 g), 190 ° C, AS
Method according to TM-D1238)

The following antioxidants were prepared. (1) Phenol-based-1: 3,9-bis [2- (3-
(3-t-Butyl-4-hydroxy-5-methylphenyl) propionyloxy) -1,1-dimethylethyl]
-2,4,8,10-Tetraoxaspiro [5,5] undecane (2) phenolic-2: pentaerythrityltetrakis [3- (3 ', 5'-di-t-butyl-4'-hydroxy] (Phenyl) propionate] (3) Phosphorus-1: Bis (2,4-di-cumylphenyl) pentaerythritol-di-phosphite

A crystal nucleating agent was prepared as follows. (1) Crystal nucleating agent: PEEK (polyether ether ketone) Melt viscosity, 0.38 to 0.50 KN · s / m2
(AMG / VX / 12)

[0074]

[Table 1]

[0075]

[Table 2]

Examples 1 to 9 The above components were dry blended in the proportions shown in Table 1. Olefin resin is 1 for 100 parts by weight of PPS resin.
It was added in the range of 0 to 100 parts by weight. After dry blending, the mixture was melt-kneaded with a twin-screw extruder set to a cylinder temperature of 290 to 320 ° C., and pelletized with a strand cutter. The resin temperature at the time of melt kneading is the same as in Examples 1 to 3 and 5.
It was 345-355 degreeC about 9-9, and 320-323 degreeC about Example 4. The screw rotation speed of the twin-screw extruder was 20 for Examples 1 to 3 and 5 to 9.
0 to 250 rpm, and 100 rpm in Example 4. After drying each pellet at 120 ° C. overnight, a test piece was injection molded. For each test piece, the average particle size, tensile elongation at break, Izod impact strength, flexural modulus at 80 ° C., MFR retention rate and oil resistance of the olefin resin were measured by the methods described above. In addition, two pellets were formed from each pellet by the same method as the above-mentioned test piece and welded to prepare a resin article having a welded portion, and the tensile breaking elongation of this resin article was evaluated. . Furthermore, the water vapor permeability (40 ° C.) and hydrogen gas permeability coefficient (40 ° C.) of each test piece were measured. The results are shown in Table 1.

As is clear from Table 1, PPS resin 10
When 10 to 100 parts by weight of the olefin resin is added to 0 parts by weight (Examples 1 to 9), the tensile strength of the resin molded product having a high tensile elongation at break and Izod impact strength and having a welded part is obtained. The breaking elongation was also high. Examples 2 and 5 are particularly excellent in heat resistance, heat stability and oil resistance,
It was found to be extremely practical and suitable for applications such as structures. When the average particle size of the olefin resin is 0.5 μm or less (Examples 1 to 3 and 5 to 9), the tensile elongation at break is greater than that in the case where the average particle size is 0.6 μm (Example 4). It can be seen that the tensile elongation at break of the resin molding having the welded portion is further excellent. Regarding other physical properties such as Izod impact strength, flexural modulus, MFR retention and oil resistance, Example 4 was as good as other Examples. Furthermore, the water vapor permeability is in the range of 0.6 g / m ² · 24H or less for all the examples, and the hydrogen gas permeability coefficient is 4 × 10 ^-15 m for all the examples.
It was below ol · m / m ² · s · Pa. From these results, it can be seen that Examples 1 to 9 can exhibit extremely excellent barrier properties.

Examples 10 to 11 As shown in Table 2, PPS-1 alone or PPS-1 to which less than 10 parts by weight of an olefin resin and an antioxidant was added was pelletized in the same manner as in Example 1, The evaluation was performed and the results are shown in Table 2. Regarding the barrier property, the water vapor permeability and hydrogen gas permeability coefficient were small and good. On the other hand, the tensile breaking elongation, the tensile breaking elongation, and the Izod impact strength of the resin molded product having the welded portion were all lower than those of Examples 1-9.

Examples 12 to 13 Pelletization and evaluation were carried out in the same manner as in Example 1 except that an olefin resin having an MFR of 3.5 g / 10 min and having no functional group was used and no antioxidant was used. The results are shown in Table 2. It was shown to. Regarding the barrier property, the water vapor permeability and hydrogen permeability coefficient were small and good. On the other hand, the tensile elongation at break of the resin molded product having a welded portion was as low as less than 20%, and the tensile elongation at break, Izod impact strength and MFR retention were also lower than those of Examples 1-9.

Comparative Example 1 The same pelletization and evaluation as in Example 1 were carried out using more than 100 parts by weight of olefin resin relative to 100 parts by weight of PPS resin, and the results are shown in Table 2. As a result, tensile elongation at break and Izod impact strength were high. However, regarding the barrier property, the hydrogen gas permeation coefficient was not so problematic, but the water vapor permeability was too large, and the result was that sufficient barrier property could not be secured. Moreover, the tensile elongation at break of the resin molding having a welded portion is as low as 15%,
The heat resistance and oil resistance of the S resin were also reduced. The MFR retention rate was also small.

Comparative Example 2 As Comparative Example 2, a commercially available material (Remalloy PX039, manufactured by Mitsubishi Engineering Plastics) was prepared as a PP / PPE composite material which has been frequently used in a resin battery case, and evaluated in the same manner as above. . This commercial material is PP / PPE /
It is a material with SEPS = 80/15/5. This material is
The tensile elongation at break, the Izod impact strength, and the flexural modulus at 80 ° C showed excellent results, but the water vapor permeability and hydrogen gas permeability coefficient were high, resulting in poor barrier properties.

Next, an example of the battery case produced using the resin composition of each of the above-mentioned examples will be briefly described with reference to FIGS. As shown in FIG. 2, the battery case 1 of this example is obtained by molding the resin compositions of Examples 1 to 9 described above by an injection molding method and further welding the lid 17.

The battery case 1 is divided into a plurality of tanks 10 by partition walls 11 as shown in FIGS. An electrode group 109 is mounted in each tank 10 and filled with an electrolytic solution. Then, the lid 17 is joined to the battery case 1 by welding. See also FIG.
Gate 16 for injection molding the battery case 1 as shown in FIG.
Zeros are located at a plurality of locations on the bottom wall 15. When molding,
In each part of the side wall 15 (FIG. 2), the partition wall 11 (FIG. 3), and the bottom wall 16 (FIG. 4), the weld line 1 is formed at the material fusion portion.
2 may be formed.

In the battery case 1 as described above, the main body and the lid 17 are made of the resin compositions shown in the above-mentioned Examples 1 to 9, so that excellent barrier properties including the welded portion and other It exhibits the above-mentioned excellent characteristics.

[Brief description of drawings]

FIG. 1 is an explanatory view of a test piece used for measuring a tensile elongation of a welded portion.

FIG. 2 is a perspective development view of a sealed battery case with a lid as seen from the side wall side in the example.

FIG. 3 is a partially cutaway perspective view of the sealed battery case in the embodiment.

FIG. 4 is a perspective view of the sealed battery case as seen from the bottom shadow side in the embodiment.

[Explanation of symbols]

1. ． ． Battery case, 2. ． ． Molded piece, 10. ． ． Tank, 11. ． ． Partition wall, 12. ． ． Weld line, 13. ． ． lid, 15. ． ． Side wall, 16. ． ． Bottom wall, 19. ． ． Break line, 71. ． ． Test pieces, 72. ． ． notch, 73. ． ． Support, 81. ． ． Plate jig,

Continued front page    (72) Inventor Mitsuhiro Yoshimura             Aichi Prefecture Kasuga-cho, Nishikasugai-gun Ochiai character Nagahata 1             Address within Toyoda Gosei Co., Ltd. (72) Inventor Yasunori Uchida             Aichi Prefecture Kasuga-cho, Nishikasugai-gun Ochiai character Nagahata 1             Address within Toyoda Gosei Co., Ltd. F-term (reference) 5H011 AA02 BB03 CC02 KK00 KK01                       KK02 KK04

Claims (8)

[Claims] 1. A polyphenylene sulfide resin (a) and an olefin resin (b) account for 80% by weight or more of the entire composition, and the content of (b) is 0 to 100 relative to 100 parts by weight of (a). The resin composition is a part by weight, and the resin composition is measured according to JIS K
Moisture permeation measured according to the -7129B method at a temperature of 40 ° C. is 0.6 g / m ² · 24H or less, and
The hydrogen permeation coefficient measured by a 2 mm-thick test piece according to JIS K-7126A at a temperature of 40 ° C. is 4.
A battery case characterized by being 0 × 10 ⁻¹⁵ mol · m / m ² · s · Pa or less. 2. The content of the (b) olefin resin in the resin composition according to claim 1,
A battery case characterized by being 10 to 100 parts by weight with respect to 00 parts by weight. 3. The resin composition according to claim 1, wherein the resin composition has a temperature of 23 ° C. and a relative humidity of 50%.
A battery case having a tensile elongation at break of 35% or more measured according to M-D638. 4. The method according to claim 1, wherein
The battery case is formed by welding a plurality of members made of the resin composition. The resin composition including the welded portion has a tensile elongation at break of 23 ° C. and 50% relative humidity.
A battery case having a value measured according to ASTM-D638 of 20% or more. 5. The method according to any one of claims 1 to 4,
The resin composition has an Izod impact strength of 500 J / m or more measured according to ASTM-D256. 6. The method according to any one of claims 1 to 5,
The (b) olefin resin is an α-olefin 60-
An battery case characterized by being an olefin-based copolymer obtained by copolymerizing 99% by weight and 1 to 40% by weight of a glycidyl ester of an α, β-unsaturated carboxylic acid as essential components. 7. The method according to any one of claims 1 to 6,
The battery case characterized in that the olefin resin (b) is dispersed in the resin composition in the form of particles having an average particle diameter of 0.5 μm or less. 8. The method according to any one of claims 1 to 7,
The resin composition further comprises (c) a phenol-based resin based on 100 parts by weight of the (a) polyphenylene sulfide resin.
A battery case containing 0.01 to 5 parts by weight of one or more antioxidants selected from thioether series and phosphorus series.