JPH0625331B2 - Adhesive composition for battery case - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an adhesive composition for a battery case, which is formed of a styrene resin.

[Prior art]

As a case (battery case) for accommodating a lead storage battery, a case formed of a styrene resin, for example, an ABS resin or an AS resin is generally used. This battery case is composed of a container portion for accommodating the lead storage battery and a lid portion having a lead electrode for sealing the upper end opening of the container portion.

In such a battery case, since the lead storage battery contains sulfuric acid (concentration of about 40%) as an electrolytic solution, it is necessary to bond and seal the container and the lid with an adhesive. As an adhesive for this purpose, a liquid epoxy resin mixed with an aliphatic amine as a curing agent is generally used.

[Problems to be solved by the invention]

However, although the above-mentioned conventionally used adhesive has a low viscosity and excellent workability, it is inferior in adhesiveness and sulfuric acid resistance. Caused the problem of seeping outside.

[Means for solving problems]

As a result of intensive studies to solve the above problems, the present inventors have found that an organic solvent that is soluble in a liquid epoxy resin as an adhesive and a styrene resin forming a battery case as an adhesion improver. It was found that the object can be achieved by using a compound containing an aromatic amine compound as a sulfuric acid-resistant curing agent in addition to the compounding of the aromatic alcohol, which has led to the completion of the present invention.

That is, according to the present invention, there is provided an adhesive composition for a battery case, which is formed of a styrene resin including a liquid epoxy resin, an aromatic amine curing agent, and an aromatic alcohol organic solvent.

The epoxy resin used in the present invention is an epoxy resin which shows a liquid state at room temperature or working temperature, and conventionally known ones are used. Specifically, for example, bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, hydrogenated bisphenol A epoxy resin, cycloaliphatic epoxy resin, glycidyl ester of organic carboxylic acids and the like. You can In the present invention, one or more of these can be used. Further, even if it is solid, by dissolving it in a liquid epoxy resin, or by dissolving it in the aromatic alcohol organic solvent used in the present invention,
Its use is possible.

In the present invention, an aromatic amine compound is used as the curing agent. As the curing agent, it is preferable to use one that is liquid at room temperature, but since an organic solvent is used in the present invention, a solid substance soluble in an organic solvent can also be used. Specific examples of such a curing agent include, for example, metaphenylenediamine, 4,4′-diaminodiphenylmethane, diaminodiphenylsulfone, 4-chloro-orthophenylenediamine, 3,3′-diethyl-4,4′-diamino. Examples thereof include phenylmethane, m-aminobenzylamine, a mixed melt thereof, a resin adduct, and the like. These aromatic amine-based curing agents have excellent sulfuric acid resistance as compared with aliphatic amine-based curing agents, and provide an adhesive portion with improved sulfuric acid resistance. The ratio of the aromatic amine-based curing agent used is 0.5 to 2 equivalents, preferably amino equivalents based on 1 equivalent of the epoxy resin.
It is 0.7 to 1.5 equivalents.

In addition, it is advantageous to use a curing accelerator for the aromatic amine-based curing agent in the composition of the present invention in order to accelerate the curing of the epoxy resin by the aromatic amine-based curing agent. As the curing accelerator, various conventionally known compounds can be used, but generally, aromatic compounds having a carboxyl group or a hydroxyl group, for example, salicylic acid, methyl salicylate, ethyl salicylate, phenol and derivatives thereof, etc. Is preferably used. It is preferable to use a curing accelerator that is liquid at room temperature, but since the organic solvent is used in the present invention, a solid substance soluble in an organic solvent can also be used. The amount of the curing accelerator used is 0.1 to 15 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the epoxy resin.

In the present invention, an aromatic alcohol organic solvent is used as the adhesion improver. Examples of the organic solvent include benzyl alcohol and phenethyl alcohol. As the organic solvent used in the present invention, it is advantageous to use one that is liquid at the working temperature. The working temperature when the composition of the present invention is used is usually room temperature to 100 ° C., and therefore, it is generally preferable to use one having a boiling point of 100 ° C. or higher.
This aromatic alcohol-based organic solvent has the function of dissolving or swelling the surface to be adhered of the battery case formed of styrene resin, increasing the area to be adhered, and providing an adhesive portion with significantly increased adhesive strength. Further, this organic solvent exhibits effects such as lowering the viscosity of the composition system to improve workability, and dissolving the curing agent or curing accelerator to improve its reactivity. The amount of the aromatic alcohol organic solvent used is 1 to 50 parts by weight, preferably 5 to 40 parts by weight, based on 100 parts by weight of the epoxy resin. If the amount of the organic solvent used is too small, the effect of improving the adhesive strength cannot be obtained. On the other hand, if the amount of the organic solvent is too large, the organic solvent exhibits a plasticizing effect and the adhesive strength of the adhesive portion is rather deteriorated.

The composition of the present invention, as long as the object of the present invention is not impaired,
Other components such as an inorganic filler, a diluent, a flame retardant, an antifoaming agent, a colorant, etc. may be added. Examples of the inorganic filler include silica, alumina, aluminum hydroxide, magnesium oxide, calcium carbonate, talc, mica, clay and the like. Examples of the diluent include monoepoxy side such as butyl glycidyl ether, phenyl glycidyl ether and alkylphenol glycidyl ether, and diepoxy side such as hexanediol diglycidyl ether.

The composition of the present invention can be prepared by uniformly mixing the above components. The composition of the present invention is used in the form of a two-pack type composed of a first liquid containing an epoxy resin and a second liquid containing an aromatic amine-based curing agent, from the viewpoint of storage stability, and both are mixed when used. Preferably. In this case, the organic solvent can be added to both the first liquid and / or the second liquid, but it is advantageous to add it to at least the second liquid. As the aromatic amine-based curing agent, a solid one or a high-viscosity one may be used in some cases, but the organic solvent has an action of dissolving the curing agent in a low-viscosity solution. Further, the curing accelerator can be added to both or one of the first liquid and the second liquid, but is usually added to the second liquid.

The composition of the present invention is suitable as an adhesive for battery cases formed from a styrene resin. In this case, as the styrene resin, in addition to polystyrene, a copolymer containing styrene or a derivative thereof as a copolymerization component,
For example, acrylonitrile / butadiene / styrene copolymer, acrylonitrile / styrene copolymer and the like can be mentioned. To bond the container part and the lid part in the battery case using the composition of the present invention, the concave part (groove part) fitted to the convex part of the lid part formed on the upper peripheral surface of the container part is provided with the present invention. The composition is injected, and the convex portion of the lid is fitted into this concave portion and pressed from above to cause the composition to undergo a curing reaction. In this case, the container part and the lid part may be preheated to 30 to 80 ° C, preferably 40 to 60 ° C, in order to accelerate the curing reaction of the composition. In order to accelerate the curing reaction of the composition, it is advantageous to use a curing accelerator together, but in this case, the temperature of the curing reaction heats up rapidly. When the aromatic alcohol-based organic solvent is not used, the temperature may reach 100 ° C. or higher, and the battery case may be deformed. Since it contains a solvent, this organic solvent alleviates the temperature rise and prevents the deformation of the battery case.

Further, lead electrode terminals are inserted and fixed in the storage part of the battery case, and the composition of the present invention can also be used for this fixing.

〔effect〕

INDUSTRIAL APPLICABILITY The composition of the present invention is suitable as an adhesive for styrene-based resins, and is particularly suitable as an adhesive for battery cases made of styrene-based resin because it has excellent adhesive strength and sulfuric acid resistance.

The adhesive portion of the battery case adhered with the composition of the present invention has not only high adhesive strength but also excellent sulfuric acid resistance, which is caused by peeling of the adhesive surface as seen in the conventional battery case. No leaching of internal sulfuric acid occurs.

Furthermore, since the composition of the present invention contains an aromatic alcohol-based organic solvent, it has a low viscosity and is excellent in workability.

〔Example〕

 Next, the present invention will be described in more detail with reference to Examples.

Example 1 As the liquid epoxy resin, a mixture of 90 parts by weight of a bisphenol A type epoxy resin (epoxy equivalent 190) and 10 parts by weight of phenyl glycidyl ether (epoxy equivalent 157) was used.

With respect to 100 parts by weight of this liquid epoxy resin, the components shown in Table 1 were mixed in the proportions (parts by weight) shown in Table 1, and the resulting mixture had a viscosity at the time of mixing, a gelation time, and a maximum exothermic temperature. And its cured product properties (tensile shear adhesive strength, sulfuric acid resistance)
Was measured as follows. The results are shown in Table 1.

(Viscosity during mixing) Measured using a Vismetron type viscometer as a viscometer (temperature 2
5 ° C).

(Gelization time) Measured by the hot plate method according to JIS C-2104.

(Maximum exothermic temperature) 25 g of the composition was poured into a paper cup, and the maximum exothermic temperature of curing in a 25 ° C atmosphere was measured with a thermometer.

(Tensile shear bond strength) Based on JIS K 6850, two ABS resin plates are bonded and the tensile shear bond strength of this adhesive plate is measured.

(Sulfuric acid resistance) The ABS resin plate prepared in the same manner as in the case of measuring the tensile shear adhesive strength was immersed in 40% sulfuric acid at 60 ° C for 7 days, and then the tensile shear adhesive strength was measured in the same manner. .

The symbols shown in Table-1 mean the following contents.

(1) Curing agent Ar-I liquid aromatic diamine-based curing agent ("Kayahard AS", manufactured by Nippon Kayaku Co., Ltd.) (2) Curing agent Ar-II liquid aromatic diamine-based curing agent ("Epicure Z", liquefaction) Shell Epoxy Co., Ltd. (3) Hardener al-I Triethylenediamine (4) Hardener al-II Liquid aliphatic amine-based hardener ("Laccamide WH-614",
(Manufactured by Dainippon Ink and Chemicals, Inc.) Example 2 In Experiment No. 1 of Example 1, a bisphenol A type epoxy resin (epoxy equivalent 190) was used as the liquid epoxy resin.
90 parts by weight and 1,6-hexanediol diglycidyl ether
The experiment was conducted in the same manner except that a mixture with 10 parts by weight of (epoxy equivalent 165) was used. As a result, this composition exhibited a viscosity upon mixing of 1700 cps, a gelation time of 120 seconds, and a maximum exothermic temperature of 60 ° C. Also, in the tensile shear adhesive strength and sulfuric acid resistance tests of the ABS resin adhesive plate obtained by using this composition, all of the adhesive plates showed breakage and showed extremely excellent adhesive strength.

Claims (6)

[Claims] 1. An adhesive composition for a battery case, which is formed from a styrene resin composed of a liquid epoxy resin, an aromatic amine curing agent, and an aromatic alcohol organic solvent. 2. The composition according to claim 1, further comprising a curing accelerator for the aromatic amine curing agent. 3. The composition according to claim 1, comprising a first liquid containing a liquid epoxy resin and a second liquid containing an aromatic amine curing agent and an aromatic alcohol organic solvent. 4. The composition according to claim 3, wherein the first liquid and / or the second liquid contains a curing accelerator. 5. A battery case formed of a styrene resin having an adhesive portion formed by using the composition according to any one of claims 1 to 4. 6. The battery case according to claim 5, wherein the styrene resin is an acrylonitrile / butadiene / styrene copolymer.