JPH08250080A - Battery jar for sealed secondary battery - Google Patents

Abstract

PURPOSE: To provide a battery excellent in rigidity, hot water permeability resistance, gas permeability resistance and hydrolysis resistance by constituting a battery jar by polyphenylene ether resin composition containing a specific amount of flame retarder represented by a specific chemical formula. CONSTITUTION: A battery jar is constituted by a resin composition containing 3 to 30 pts.wt. at least one kind of flame retardant represented by formulas I, II relating to 100 pts.wt. polyphenylene ether resin component. In the formula, Q1 to Q4 represent an alkyl group of respective carbon number 1 to 6 or hydrogen, Q1' to Q4' represent respectively hydrogen or alkyl groups of carbon number 1 to 6, and R1 to R4 represent respectively a methyl group or hydrogen. n shows an integer of 1 or more, n1, n2 show an integer of 0 to 2, and m1 to m4 show an integer of 1 to 3. By this constitution, a secondary battery life is extended, also to be able to form a battery in small size into a high function.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to members for various secondary batteries such as lead storage batteries and alkaline batteries. More specifically, it relates to a battery case for a sealed type secondary battery.

[0002]

2. Description of the Related Art Applications of various secondary batteries are being expanded from the viewpoints of driving sources for mobile devices, power sources for computer data backup, effective use of solar cell energy, and environmental protection. In particular, it is well known that a secondary battery is often used to supply the required power of an internal combustion engine of an automobile, but further, a so-called electric vehicle using the secondary battery itself as a drive source instead of the internal combustion engine. Has been actively developed in recent years. With the development of industrial technology, the demand for secondary batteries tends to increase more and more, and the demand for secondary batteries having small size, light weight, and large electric capacity is increasing.

In such a secondary battery, a battery case containing an acid or alkali electrolyte and electrodes is indispensable. The characteristics required for the battery case are resistance to strong acids and alkalis and impact resistance sufficient to withstand external impact.
Furthermore, this battery case must be one in which heat generated by a chemical reaction during charging and products such as water and hydrogen gas are sufficiently taken into consideration. Especially, in the sealed type secondary battery,
In order to meet the demand for smaller size and lighter weight,
It must be thin and have heat resistance, be able to withstand an increase in internal pressure during charging, and be able to properly maintain the properties of the electrolyte for a long period of time.

Conventionally, polypropylene resin and ABS resin have been widely used as materials for battery cases. However, although polypropylene resin has excellent fluidity at the time of molding, hot water permeation resistance, and gas permeation resistance, in the injection molding of a product with a thin rib structure, the shrinkage rate is large, so sink marks are likely to occur.
Further, since the rigidity, especially the rigidity at high temperature (rigidity at the time of heat) is small, it is necessary to increase the wall thickness or mix a reinforcing material. On the other hand, since ABS resin has high hot water permeability and high gas permeability, when it is used for a long period of time, the properties of the electrolyte cannot be maintained, and the electrolyte is replaced or water is replenished. It is necessary to take time and effort for maintenance as a battery case. In addition, JP-A-6-20381
Japanese Unexamined Patent Publication No. 4 discloses a battery case for a sealed secondary battery made of a polyphenylene ether-based resin and a polystyrene resin. The battery container molded with the resin composition has a thermal strain when the lid is thermally welded. Therefore, the problem of stress cracking and hydrolysis resistance are not sufficient.

[0005]

As described above, the conventional materials have their respective problems, and they satisfy all of moldability, rigidity, hot water permeation resistance, gas permeation resistance, and hydrolysis resistance. It was not possible to obtain a battery case for the secondary battery. The present invention solves the problems of the prior art, has excellent rigidity, and is capable of exhibiting the performance of the initial electrolyte over a long period of time. It is a sealed type excellent in hot water permeation resistance, gas permeation resistance, and hydrolysis resistance. The battery case for the secondary battery is provided.

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have made up a polyphenylene ether resin composition containing a flame retardant having a specific structure. Naru battery case has excellent moldability, rigidity,
We found that it has resistance to hot water permeation and hydrolysis resistance,
The present invention has been completed. That is, the present invention provides the following chemical formula (I)
And a polyphenylene ether-based resin composition containing 3 to 30 parts by weight of at least one flame retardant represented by the chemical formula (II) per 100 parts by weight of the resin component. It is a tank.

[0007]

Embedded image

(In the formula, Q1, Q2, Q3 and Q4 each represent an alkyl group having 1 to 6 carbon atoms or hydrogen;
1, R2, R3 and R4 each represent a methyl group or hydrogen. n is an integer of 1 or more, n1 and n2 are integers from 0 to 2, and m1, m2, m3 and m4 are integers from 1 to 3. )

[0009]

[Chemical 4]

(In the formula, Q1, Q2, Q3 and Q4 each represent an alkyl group having 1 to 6 carbon atoms, and Q1 'and Q1
2 ', Q3', Q4 'are each hydrogen or carbon number 1
Represents an alkyl group from 6 to 6. n represents an integer of 1 or more. ) Hereinafter, the present invention will be described in detail. The polyphenylene ether resin composition (hereinafter abbreviated as PPE resin composition) constituting the present invention is a polyphenylene ether resin (hereinafter abbreviated as PPE resin) alone or PPE resins 5 to 9.
It is a resin composition containing 5% by weight and a polyphenylene ether resin (hereinafter abbreviated as PPE resin) consisting of 95 to 5% by weight of a polystyrene resin (hereinafter abbreviated as PS resin).

The PPE resin in the present invention comprises the constitutional units shown in the following chemical formula 5 and has a reduced viscosity (0.5 g / d).
1, chloroform solution, measured at 30 ° C.) is 0.15 to 0.
A homopolymer or copolymer in the range of 8, preferably in the range of 0.2 to 0.7 can be used.

[0012]

Embedded image

(R5, R6, R7 and R8 are each hydrogen, halogen, a primary or secondary lower alkyl group having 1 to 7 carbon atoms, a phenyl group, a haloalkyl group, an aminoalkyl group and a hydrocarbon oxy group. And at least 2
Carbon atoms are selected from the group consisting of halohydrocarbonoxy groups separating a halogen atom and an oxygen atom and may be the same or different. ) Specific examples of homopolymers of PPE resins include poly (2,
6-dimethyl-1,4-phenylene ether), poly (2-methyl-6-ethyl-1,4-phenylene ether), poly (2-methyl-6-phenyl-1,4-phenylene ether), poly ( 2,6-dichloro-1,4-
Phenylene ether). Further, specific examples of the copolymer include 2,6-dimethylphenol and 2,6-dimethylphenol.
Examples thereof include copolymers with 3,6, -trimethylphenol and 2-methyl-6-butylphenol. Among these, poly (2,6-dimethyl-1,4-phenylene ether) and 2,6-dimethylphenol and 2,3,3
A copolymer with 6, -trimethylphenol is preferable,
More preferred is poly (2,6-dimethyl-1,4-phenylene ether).

The method for producing the PPE resin used in the present invention is as follows:
It is not particularly limited as long as it is obtained by a known method, and for example, US Pat. Nos. 3,306,874, 3,330,875 and 3,257,357.
No. 3,257,358, Japanese Patent Publication No. 52-
It can be produced by the method described in JP 17880A, JP 50-51197A, JP 63-152628A, or the like. Further, the PPE resin used in the present invention is the above-mentioned P
In addition to the PE resin, the PPE resin and the α, β-unsaturated carboxylic acid or derivative thereof in the presence or absence of a radical generator in a melted state, a dissolved state, or a slurry state in an amount of 80 to 3
It may be a modified PPE resin (0.01 to 10% by weight is grafted or added) obtained by reacting at a temperature of 50 ° C., and further the above PPE resin and modified P
It may be a mixture of PE resins in any proportion.

The PS resin used in the present invention is generally a vinyl aromatic polymer or a rubber-modified aromatic polymer. As vinyl aromatic polymers, in addition to styrene,
Nuclear alkyl-substituted styrenes such as o-methylstyrene, p-methylstyrene, m-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, p-tert-butylstyrene, α-methylstyrene, α-methyl-p-methyl Examples thereof include polymers such as α-alkyl-substituted styrenes such as styrene, copolymers of at least one of these with at least one other vinyl compound, and copolymers of two or more thereof. Examples of the compound copolymerizable with the vinyl aromatic compound include methyl methacrylate, methacrylic acid esters such as ethyl methacrylate, acrylonitrile, unsaturated nitrile compounds such as methacrylonitrile, and acid anhydrides such as maleic anhydride. To be Particularly preferred polymers among these polymers are polystyrene and styrene-acrylonitrile copolymer (AS resin).
Is.

Examples of the rubber used for the rubber-modified vinyl aromatic copolymer include polybutadiene, styrene-butadiene copolymer, polyisoprene, butadiene-isoprene copolymer, natural rubber and ethylene-propylene copolymer. You can In particular, polybutadiene and a styrene-butadiene copolymer are preferable, and as the rubber-modified aromatic polymer, rubber-modified polystyrene (HIPS),
Rubber-modified styrene-acrylonitrile copolymer (ABS
Resin) is preferred.

The resin composition constituting the present invention may contain a thermoplastic elastomer for the purpose of improving impact resistance. As the thermoplastic elastomer, for example,
Styrene-butadiene copolymer, styrene-isoprene copolymer, ethylene-propylene copolymer, ethylene-
Vinyl acetate copolymer, thermoplastic urethane elastomer,
Examples thereof include fluoroelastomers. The flame retardant used in the present invention is a phosphoric acid ester compound represented by the following chemical formulas (I) and (II).

[0018]

[Chemical 6]

(In the formula, Q1, Q2, Q3 and Q4 each represent an alkyl group having 1 to 6 carbon atoms or hydrogen;
1, R2, R3 and R4 each represent a methyl group or hydrogen. n is an integer of 1 or more, n1 and n2 are integers from 0 to 2, and m1, m2, m3 and m4 are integers from 1 to 3. )

[0020]

[Chemical 7]

(In the formula, Q1, Q2, Q3, and Q4 each represent an alkyl group having 1 to 6 carbon atoms, and Q1 'and Q1
2 ', Q3', Q4 'are each hydrogen or carbon number 1
Represents an alkyl group from 6 to 6. n represents an integer of 1 or more. ) Q1, Q2 in the chemical formula (I) and the chemical formula (II)
A methyl group is particularly preferable among Q3 and Q4. In the chemical formula (I) and the chemical formula (II), n is an integer of 1 or more, and the heat resistance and workability vary depending on the number. The preferable range of n is 1 to 5. The phosphoric acid ester may be a mixture of n-mers.

The phosphoric acid ester compound, which is a constituent of the present invention, has a binding structure of "specific bifunctional phenol" and a terminal structure of "specific monofunctional phenol".
Examples of the "specific bifunctional phenol" include 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) methane and bis. (4-hydroxy-3,5-dimethylphenyl) methane, 1,1-
Examples thereof include bisphenols such as bis (4-hydroxyphenyl) ethane, and among them, bisphenol A is preferable.

As the "specific monofunctional phenol", monoalkylphenol, dialkylphenol and trialkylphenol can be used alone or as a mixture of two or more kinds. Among them, cresol, dimethylphenol (mixed xylenol), 2,6-dimethylphenol,
Trimethylphenol is preferred. The phosphoric acid ester compound, which is a constituent component of the present invention, is a compound in which two or more phosphoric acid esters are bound by a specific bifunctional phenol (bisphenol), and thereby volatility is significantly suppressed. Moreover, it exhibits a high level of performance that cannot be achieved with conventional polyphosphates such as those bound with resorcinol or hydroquinone. Specifically, in a product molded with a resin composition using a conventional polyphosphate, appearance defects such as discoloration and blistering that occur under high temperature and high humidity conditions were molded with the resin composition constituting the present invention. The battery case for the sealed secondary battery can be suppressed.

The product molded with the PPE resin composition using monoalkylphenol, dialkylphenol, or trialkylphenol as the "monofunctional phenol" uses a phosphate ester compound having a terminal structure with an unsubstituted monofunctional phenol. Compared to when
Thermal stability and hydrolysis resistance are further improved. The effect of nuclear substitution of 1 to 3 alkyl groups in this monofunctional phenol is remarkable from the viewpoint of improving the hydrolysis resistance, and cannot be predicted from the change in the acidity of the alkyl-substituted monofunctional phenol.

The content of the flame retardant composing the present invention may be any amount which is effective for making the battery case material for a sealed secondary battery flame-retardant, and 100 parts by weight of the resin component composing the battery case. In contrast,
It is 3 to 30 parts by weight, preferably 5 to 25 parts by weight. If it is less than 3 parts by weight, the flame retarding effect is not sufficient, and if it exceeds 30 parts by weight, the heat resistance is remarkably reduced and the material cost is also increased, resulting in poor practicability. Thus, the phosphoric acid ester constituting the present invention simultaneously has a binding structure with bisphenols and a terminal structure with an alkyl-substituted monofunctional phenol, and is obtained by molding a PPE resin composition using this phosphoric acid ester compound. The obtained product exhibits excellent properties of maintaining initial electrical properties, flame retardancy, and appearance even when contacted with moisture in a heated atmosphere.

A conventional product molded from a resin composition using an organic phosphate compound having a large molecular weight, such as resorcinol polyphosphate or hydroquinone polyphosphate, is inferior in thermal stability during molding and Since a reaction occurs between the acid ester compound and the resin and causes a problem such as gelation, the resin composition cannot be processed at a high temperature without loss. In addition, the acidic component such as phosphoric acid generated by the decomposition of the phosphoric acid ester compound, the decomposition of the resin is promoted and the molecular weight decreases,
It causes deterioration of physical properties and has problems in practicality and long-term stability. Furthermore, the acidic component produced by the decomposition of the phosphoric acid ester makes contact with the resin composition of the molding machine, the metal members such as barrels and screws, the surface of the mold, and the molded product when it is used. There was a problem of corroding the metal parts of the product.

On the other hand, the product of the present invention is not only hydrolyzable in a high temperature and high humidity environment, but is also excellent in thermal stability during molding, and it emits electricity due to smoke, volatilization and water absorption during molding. Not only does not deteriorate the physical properties, flame retardancy, and appearance, but the degradability of the PPE resin composition is significantly suppressed,
It also solves the problem of corroding the metal parts of molding machines and the metal parts with which molded products come into contact. The stainless steel fiber, glass flake, glass fiber, ceramic, mica, carbon fiber, graphite, talc is used for the purpose of improving mechanical properties (particularly imparting rigidity), dimensional accuracy, heat resistance, etc. to the PPE resin composition constituting the invention. Ceramics such as boron nitride can be added, but it is necessary to consider conductivity and resistance to an electrolytic solution.

In addition, various additives such as a fluidity improver, a plasticizer, a release agent, an ultraviolet absorber, an antioxidant, a light stabilizer, etc. are added to the PPE resin composition within the range that does not impair the effects of the present invention. A metal deactivator and a colorant can be added. The method for producing the PPE resin composition used in the present invention is not particularly limited, but it can be produced by kneading using a kneader such as an extruder, a heating roll, a kneader, a Banbury mixer. Furthermore, the method of molding the battery case for a secondary battery according to the present invention is not particularly limited, but the injection molding method, vacuum molding method, pressure molding method, press method and the like that are commonly used can be used.

[0029]

EXAMPLES The present invention will be specifically described below with reference to examples. The physical properties of the resin composition are standard conditions (molding temperature: 30
Temperature at which a test piece can be molded with an injection pressure of 0 to 600 kg / cm ² , injection pressure: 100 at the short shot point
(kg / cm ² plus, mold temperature: 60 ° C) to make a test piece by injection molding, and moisture permeability and gas permeability are extruded (40mm full flight) under standard conditions (temperature suitable for sheet molding). A sheet was prepared by screwing L / D = 27) and evaluated according to the following test method. (1) Heat distortion temperature: ASTM-D648 (2) Flexural modulus: ASTM-D790 (3) Izod impact strength: ASTM-D256, 1 /
Use of 4-inch thick notched test piece (4) Wet heat treatment: Treat for 500 hours in an atmosphere of 100 ° C and 100% RH. (5) Humidity: According to JIS-K7129B (red sensor method), test temperature 40 ± 5 ° C., relative humidity difference 100%,
It is shown in g of water vapor permeating the sample per 50 cm ² of area for 24 hours. (6) H ₂ gas permeability: based on JIS-K7126A (differential pressure method), test temperature 40 ± 5 ° C., test pressure 760 m
The amount of gas that permeates the sample per cm ³ area per 38.46 cm ² in mHg is shown in cm ³ .

[0030]

Examples 1 and 2 and Comparative Example 1 Using the materials shown in Table 1, the compounds shown in Table 2 were kneaded by a twin-screw extruder (ZSK-40, manufactured by Werner Co.) at a temperature of 280 ° C. to prepare pellets. Then, a sample for measuring physical properties, moisture permeability, and gas permeability was prepared. The measurement results are shown in Table 2.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

The battery case of the present invention is excellent in rigidity, resistance to hot water and resistance to gas permeation. Therefore, in the sealed secondary battery using the battery case according to the present invention, the rigidity and heat resistance are high, the structure is excellent, the hot water permeation resistance is excellent, the loss of water is prevented, and the secondary battery is The life is extended. INDUSTRIAL APPLICABILITY The present invention satisfies the severe performance required for a secondary battery, and responds to downsizing and high functionality of the secondary battery.

Claims (1)

[Claims] 1. The following chemical formula (I) and chemical formula (II):
At least one of the flame retardants represented by
A battery case for a sealed secondary battery, comprising a polyphenylene ether resin composition in an amount of 3 to 30 parts by weight based on parts by weight. Embedded image (In the formula, each of Q1, Q2, Q3, and Q4 has 1 carbon atom.
Represents an alkyl group of 6 to 6 or hydrogen, R1, R2, R
3 and R4 each represent a methyl group or hydrogen. n is an integer of 1 or more, n1 and n2 are integers of 0 to 2,
m1, m2, m3 and m4 represent integers from 1 to 3. ) (In the formula, each of Q1, Q2, Q3, and Q4 has 1 carbon atom.
To Q6 alkyl groups, Q1 ', Q2', Q3 ',
Q4 'represents hydrogen or an alkyl group having 1 to 6 carbon atoms. n represents an integer of 1 or more. )