JPH0152409B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing a tubular fuse. More specifically, we use a specific one-component thermosetting epoxy resin composition that is stable for a long time at room temperature, but hardens in a short time under heating and curing conditions to form a cured product with good physical properties. The present invention relates to a method for manufacturing a tubular fuse, which comprises bonding a glass tube and an end cap. Tubular fuses are widely used as protection devices against overcurrents in electrical circuits. Conventional tubular fuses are made of metals that easily melt due to heat, such as lead, copper, etc., when an overcurrent exceeding a certain value flows.
An element made of tin, zinc, bismuth, cadmium, aluminum, etc., alone or of an alloy, is stretched and enclosed in a glass cylinder with metal end caps at both ends. The end cap of the element is usually fixed by soldering, and the glass tube and the end cap are fixed with adhesive. Epoxy resin adhesives are commonly used to bond the glass barrel and end cap of tubular fuses because of their excellent physical properties such as the adhesive properties of cured resins, water resistance, and chemical resistance. Two-component types that cure at room temperature are the mainstream. In general, one-component epoxy resin adhesives are made by blending epoxy resin with latent curing agents such as dicyandiamide, boron trifluoride, amine complex compounds, and borated amine complex compounds, and can withstand long-term storage at room temperature. You can work without worrying about pot life,
Although the physical properties of the cured resins are excellent, they all have the drawback of requiring high temperatures and long periods of time for curing. For example, the normal condition is to hold the glass tube at a temperature of 170 to 200 degrees Celsius for 30 to 120 minutes, but if the glass tube and end cap of a tubular fuse are bonded under these conditions, the glass tube will not break due to heat shrinkage after the resin hardens. Although the reason is not clear, rust may form on the end caps and elements, possibly due to the gas generated, which may impair the electrical characteristics of the fuse. Therefore, this method has not been adopted. On the other hand, while two-component epoxy resin adhesives are conveniently available at low prices and can be cured at room temperature, if the main ingredient and curing agent are not weighed or mixed properly, the resin will not cure or the pot life will be short. On the contrary, the curing time is long. For this reason, when used in the manufacture of tubular fuses, precise and complicated work is required to weigh and mix the base resin and curing agent, and after mixing, a relatively large amount of resin per unit area must be used up quickly. First, the next step, soldering the element and end cap, cannot be started until about 24 hours have passed after applying the adhesive. In addition, problems such as resin burning, adhesive peeling, and glass cracking caused by the heat during soldering are serious, and the defective rate has reached several percent. Under these circumstances, there is a strong desire to improve the method of manufacturing tubular fuses. While conducting research to solve the drawbacks of the manufacturing method for tubular fuses using epoxy resin compositions, the present inventors treated the surface of a powder made of an addition compound of an epoxy compound and a specific amine with an acidic substance. It was discovered that the above-mentioned drawbacks in manufacturing tubular fuses could be overcome by using an epoxy resin composition using the obtained fine powder compound as a curing agent as an adhesive between a glass cylinder and an end cap, and the present invention was achieved. This is what I did. That is, the present invention uses (1) an epoxy resin and (2) an epoxy compound with a dialkylamine (alkyl group is substituted) when bonding the glass barrel and end cap of a tubular fuse with an adhesive. It is characterized by using a one-component thermosetting epoxy resin composition comprising a latent curing agent obtained by treating the powder surface of an addition compound obtained by reacting with an acidic substance (optional). This is a method of manufacturing a tubular fuse. The epoxy resin used in the present invention has on average two or more epoxy groups per molecule, such as polyhydric phenols such as bisphenol A, bisphenol F, catechol, and resorcinol, or glycerin and polyethylene glycol. Polyglycidyl ether obtained by reacting a polyhydric alcohol such as epichlorohydrin with epichlorohydrin, or glycidyl ether ester obtained by reacting epichlorohydrin with a hydroxycarboxylic acid such as p-oxybenzoic acid or β-oxynaphthoic acid, or phthalic acid. , polyglycidyl esters obtained from polycarboxylic acids such as terephthalic acid, or glycidylamine compounds obtained from 4,4'-diaminodiphenylmethane and m-aminophenol, as well as epoxidized novolak and epoxidized polyolefin. Examples are given, but the invention is not limited to these. Examples of the dialkylamine that is a raw material for the latent curing agent of the one-component epoxy resin composition used in the present invention include dimethylamine, diethylamine, dipropylamine, N-methylethylamine, N-ethylisobutylamine, diallylamine, Examples include dibenzylamine, N-ethylethanolamine, diethanolamine, and the like. There are no particular restrictions on the epoxy compounds to be reacted with these dialkylamines, but examples include monoepoxy compounds typified by butyl glycidyl ether and phenyl glycidyl ether, polyhydric phenols, polyhydric carboxylic acids, etc. as exemplified above. Examples include epoxy resins obtained from amines, and by mixing one or more of these epoxy compounds, an adduct having an arbitrary softening point can be obtained. A dialkylamine adduct of an epoxy compound can be easily obtained by dissolving the epoxy compound in a solvent, adding dropwise excess dialkylamine, reacting while heating, and after the reaction is completed, distilling off the unreacted amine and the solvent. The solvent may be one that dissolves the epoxy compound, such as tetrahydrofuran, dioxane,
Examples include acetone, methyl ethyl ketone, toluene, monochlorobenzene, methyl cellosolve, and ethyl cellosolve. The addition compound is powdered by an appropriate method.
Although the particle size of the powder is not particularly limited, if the particle size is too large, the curing of the one-component epoxy resin composition may be delayed or the physical properties of the cured resin may be impaired. If the particle size is too small, technical difficulties may arise during the next step of surface treatment. The preferred particle size is less than 500μ, optimally on the order of 5-150μ. The latent curing agent used in the present invention can be obtained by treating the powder surface of the finely powdered addition compound with an acidic substance. The surface of the addition compound powder can be treated with an acidic substance by exposing the powder to a gaseous acid or by dipping and dispersing the powder in a dilute acidic substance solution, followed by fractionation and drying. Acidic substances used for surface treatment include gaseous and liquid inorganic and organic acids such as sulfurous acid, hydrochloric acid, carbon dioxide, sulfuric acid, phosphoric acid, boric acid, formic acid, oxalic acid, acetic acid, propionic acid, lactic acid, caproic acid, Examples include salicylic acid, tartaric acid, succinic acid, adipic acid, sebacic acid, p-toluenesulfonic acid, phenol, pyrogallol, tannic acid, rosin, polyacrylic acid, polymethacrylic acid, alginic acid, phenolic resin, and resorcinol resin. The amount of these acidic substances used should be sufficient to neutralize the amino groups exposed on the surface of the powder of the adduct, and if the amount used is too large, the effect of accelerating the curing of the epoxy resin will decrease. There is a risk. Therefore, it is preferable to quantify the amount of amine using a portion of the sample before treatment to determine the required amount. The one-component thermosetting epoxy resin composition used in the first invention of the present application can be obtained by simply and uniformly mixing the latent curing agent thus obtained with the epoxy resin. The mixing amount is preferably 0.1 to 30 parts by weight of the latent curing agent per 100 parts by weight of the epoxy resin; if it exceeds 30 parts by weight, the cured product may be colored or its performance may deteriorate. In the curable composition used in the present invention obtained as described above, known latent curing accelerators for epoxy resins such as guanidine, hydrazine, amidine, triazine, urea, and azo compounds can be used in combination. . Specifically, for example, acetyl semicarbazide, acetaldehyde semicarbazone,
N,N'-diphenylguanidine, methylguanidine, biguanide, dicyandiamide, dicyandiamidine, hydrazobenzene, azobenzene,
Melamine, N'-(3-chlorophenyl)-N,N
-dimethylurea, N'-(3,4-dichlorophenyl)-N,N-dimethylurea, acetylmethylurea, benzylurea, thiourea, etc., and the amount used is 1 to 100 parts by weight of the epoxy resin. 20
Parts by weight are preferred. Furthermore, additives used in ordinary epoxy compositions, such as plasticizers, solvents,
There is no problem in blending viscosity modifiers, reactive diluents, flexibility imparting agents, fillers, coloring agents, and other modifiers for various purposes, and these blends also meet the purpose of the present invention. It is included within that scope. The one-component thermosetting composition used in the present invention obtained in this way has excellent storage stability at room temperature, so it can be prepared in advance at once, without the need for complicated operations each time. I no longer have to worry about my pot life. In addition, under heating conditions, it cures in more than 10 times less time than previously known one-component epoxy resin compositions, provides strong adhesion between glass and metal, and the cured resin has improved heat resistance. There is. The one-component epoxy resin used in the present invention has excellent performance as described above, so when it is used to manufacture tubular fuses, the amount of adhesive used per unit area is reduced due to the reliability of the bond. can,
As a result of the drastic reduction in resin damage caused by heat during soldering between elements and end caps, as well as glass breakage due to heat shrinkage, we were able to complete automation of the production line. In addition, for 6.4 x 30 mm type rated 6A tubular fuses manufactured using conventionally known epoxy resin compositions, those that can withstand use up to a breaking capacity of 250 V x 500 A, which is the technical standard of the Electrical Appliance and Materials Control Law. It was rare. However, the fuse of the same type according to the present invention has a power rating of 250V, which is the U.S. UL standard.
It was surprising that even a high breaking capacity of 10,000A became usable. The second proposal of the present invention is to use an epoxy resin composition obtained by adding an imide compound to the specific epoxy resin composition used in the first invention of the present application to bond the glass cylinder and the end cap. A method for manufacturing a tubular fuse, the method comprising:
The purpose is to impart flexibility to the cured resin of the epoxy resin composition used in the present invention and to improve the stable manufacturing method of tubular fuses. As mentioned above, the one-component thermosetting epoxy resin composition obtained in the first invention of the present application can improve the reliability of adhesion when used for adhering the glass barrel and end cap of a tubular fuse. This reduced the amount of adhesive used per unit area, which made it possible to automate production lines and use it for products with high breaking capacity. It turned out that impact resistance was required. Generally, when a plasticizer that imparts flexibility to a cured resin, such as dibutyl phthalate, dioctyl phthalate, nitrile rubber, polyethylene glycol, polypropylene glycol, polyvinyl butyral, or polyvinyl formal, is mixed and used, the flexibility of the resin itself is improved. When used in the present invention, damage such as end cap peeling and glass cracking actually increases. On the other hand, it has been found that those containing an imide compound completely solve these drawbacks. General plasticizers are non-reactive with epoxy resins and must be added in large quantities, whereas imide compounds participate in the curing reaction when added in small amounts, and this improves the defective rate to below 0.05% in the manufacture of tubular fuses. This is thought to be the cause. That is, the second invention of the present application is, when bonding the glass barrel and end cap of a tubular fuse using an adhesive, as the adhesive (1) an epoxy resin;
(2) a latent curing agent obtained by treating the powder surface of an addition compound obtained by reacting an epoxy compound with a dialkylamine (the alkyl group may be substituted) with an acidic substance; and (3) an imide. This is a method for manufacturing a tubular fuse characterized by using a one-component thermosetting epoxy resin composition comprising a compound. The epoxy resin and fine powder latent curing agent that are raw materials for the one-component thermosetting epoxy resin composition used in the present invention are those described in the first invention of the present application, and are used in exactly the same manner. Imide compounds used in the present invention include, for example, phthalimide, succinimide, 2-ethyl-2-
Examples include phenylglutarimide, uracil, 5-[bis(2-chloroethyl)amino]uracil, and the like. The mixing amount is preferably 0.5 to 20 parts by weight of the imide compound per 100 parts by weight of the epoxy resin, and if it exceeds 20 parts by weight, the physical properties of the cured product will deteriorate. The one-component curable composition used in the second invention of the present application is
(1) Epoxy resin; (2) Latency obtained by treating the powder surface of an addition compound obtained by reacting an epoxy compound with a dialkylamine (alkyl group may be optional) with an acidic substance. It can be obtained by simply uniformly mixing the curing agent and (3) the imide compound. The obtained composition may also contain the same conventionally known latent curing agents and additives for epoxy resins as described in the first invention of the present application. Examples of manufacturing the latent curing agent for epoxy resin compositions used in the present invention are shown below. In the examples, "parts" indicate parts by weight. Reference Example 1 150 parts of ESCN-220L (cresol novolac type epoxy resin manufactured by Sumitomo Chemical Co., Ltd., softening point 73°C, epoxy equivalent 215) was dissolved in 400 parts of ethyl cellosolve, and 234 parts of dimethyl was added while stirring with heating. Add the amine aqueous solution (40%) dropwise as soon as possible. 50
After 7 hours of reaction at ~80°C, remove unreacted amine and solvent.
Distill under reduced pressure while heating at 100-160°C. Next, the reactant was dissolved in 150 parts of toluene, and the unreacted amine in the resin was similarly distilled off under reduced pressure to obtain 180 parts of an adduct. Disperse 10 parts of the adduct, ground into 200 mesh passes, in 30 parts of water. 32 parts of a 0.5% lactic acid aqueous solution is added dropwise to this dispersion while stirring.
After stirring for 10 to 20 minutes, the mixture was filtered and dried under reduced pressure to obtain 9.0 parts of a treated product. This is referred to as latent curing agent (A). Reference example 2 75 parts of ESCN-220L (above) and ESA-011 (Epivis type epoxy resin manufactured by Sumitomo Chemical Co., Ltd.) Softening point 69
℃. Epoxy equivalent weight 489. ) is dissolved in 600 parts of ethyl cellosolve, and 190 parts of dimethylamine aqueous solution (40%) is added dropwise as soon as possible while stirring with heating. 180 parts of an adduct was obtained in the same manner as in Reference Example 1. 10 parts of adduct crushed into 200 mesh
Dispersed in 30 parts of water, 0.3% in the same manner as in Reference Example 1
was treated with 30 parts of acetic acid aqueous solution to obtain 8.5 parts of a treated product. This is referred to as latent curing agent (B). Reference example 3 ESA-017 (Epivis type epoxy resin manufactured by Sumitomo Chemical Co., Ltd. Softening point 130°C. Epoxy equivalent 1830.)
130 parts and ELA-134 (Epivis type epoxy resin manufactured by Sumitomo Chemical Co., Ltd. Softening point 22°C. Epoxy equivalent 244.)
20 parts were dissolved in 50 parts of ethyl cellosolve and reacted with 120 parts of a solution of diethylamine in ethyl cellosolve (40%) in the same manner as in Reference Example 1 to obtain 152 parts of an adduct. 10 adducts crushed into 200 mesh passes
1 part in 30 parts of water, and in the same manner as in Reference Example 1.
It was treated with 120 parts of a 0.16% resorcinol novolak resin aqueous solution to obtain 8.7 parts of a treated product. This is referred to as latent curing agent (C). Reference examples 4-12 Sumiepoxy ELA-128 (epoxy resin manufactured by Sumitomo Chemical Co., Ltd., softening point 8-12℃, epoxy equivalent 184
~194) An epoxy resin composition was prepared by blending 100 parts of a latent curing agent (names are indicated by reference symbols) and an imide compound in amounts shown in Table 1. Using this composition, curing time, adhesive strength, and storage stability of the composition were measured. Table 1 shows the measurement results.
Shown below. The curing time was measured using a hot plate gel timer (manufactured by Nisshin Kagaku Co., Ltd.). Storage stability was expressed as the number of days required for the viscosity to rise to twice the originally measured value. Adhesive strength is 25 x 100 after polishing and degreasing.
A 25 x 12.5 (mm) lap was bonded using a x 1.6 (mm) mild steel plate, and the average shear strength (n = 5) was obtained at room temperature after being compressed with clips and cured for the specified period.
was measured and determined.

[Table] From the results in Table 1, the epoxy resin composition used in the present invention has extremely superior performance in terms of heat curing time without impairing storage stability compared to previous similar epoxy resin compositions. It can be seen that it has.
In other words, when cured at a temperature of 130°C, although the conventional product does not cure even after 120 minutes,
Those used in this invention cure within about 15 minutes. Examples 1 to 7, Comparative Examples 1 to 2 A one-component thermosetting epoxy resin composition obtained in Reference Examples 4 to 10 was dot-coated on both ends of the glass tube of a 6.4 x 30 mm type tubular fuse, After installing two brass end caps, heat to 130℃.
The adhesive was maintained at a temperature of 20 minutes to complete adhesion. The element was then soldered to the end cap to obtain a tubular fuse. In the same manner, 10,000 tube-shaped fuses were manufactured, and the glass tube breakage rate and adhesion failure rate were determined by visual observation and finger twisting test, and are shown in Table 2. In addition, in this example, instead of the epoxy composition used in the present invention, the one-component epoxy resin composition of Reference Example 11 was used, and the curing conditions were 200 ° C. for 30 minutes.
Others are tubular fuses manufactured according to this example.
Similar test results for 10,000 pieces are shown in Table 2 as Comparative Example 1. Similarly, as a comparative example, a two-component epoxy resin composition was used, and after applying the entire surface to both ends of the glass cylinder and attaching end caps, the composition was cured at 25°C for 24 hours, and then post-treated in the same manner as in Example 1. Table 2 also shows the test results for the obtained tubular fuse. The epoxy resin used in this case was a product of Cemedine Co., Ltd.
#1500.

[Table] From the results in Table 2, it is clear that the method for manufacturing a tubular fuse of the present invention is extremely superior in terms of productivity, quality, and handling compared to the conventional manufacturing method. Examples 8 to 9 The one-component epoxy resin composition used in Examples 1 and 7 was used to produce 6.4×
We manufactured 100,000 30mm type tubular fuses and determined the defective rate. However, the epoxy resin composition is dot-coated on the glass cylinder, and after the fuse element and soldered end cap are attached, the end cap is held at a temperature of 250°C for 1.5 seconds to simultaneously perform soldering and resin curing. The device was designed to allow As a result, the glass breakage rate of the tubular fuse manufactured using the epoxy resin composition used in Example 1 was 1.1%, which was worse than in Example 1. On the other hand, the tubular fuse manufactured using the epoxy resin composition used in Example 7 showed extremely good results with an adhesion failure rate of 0.004% and a glass breakage rate of 0.002%. Example 10, Comparative Example 3 Regarding the element of the 6.4 x 30 mm type tubular fuse (copper element) that passed the manufacturing pass in Example 1, it was rated at 160% of the rated current at 10 A based on the technical standards of the Electrical Appliance and Material Control Act. fusing time and
Table 3 shows the temperature rise values at 115% of the rating. As a comparative example, we measured the fusing time and temperature rise of a 6.4 x 30 mm type tubular fuse (copper element) manufactured using the two-component epoxy resin of Comparative Example 2 at a rated current of 10 A. The results are shown in Table 3. Indicated.

[Table] Example 11, Comparative Example 4 The rated current of the 6.4 x 30 mm type tubular fuse (copper element) element that passed manufacturing in Example 5 based on the technical standards of the Electrical Appliance and Material Control Law.
The fusing time at 160% of the rating at 8A and the
The temperature increase value at 115% was measured and shown in Table 4. As a comparative example, for a 6.4 x 30 mm type tubular fuse (copper element) that was manufactured using the two-component epoxy resin of Comparative Example 2, the fusing time and temperature rise value were similarly determined at a rated current of 8 A and are shown in Table 4. .

[Table] As is clear from the results in Tables 3 and 4, when comparing fuses with the same rated current and the same fusing characteristics, fuses manufactured using conventional two-component epoxy resins However, the fuse manufactured by the method of the present invention is
Lower resistance (thicker) elements can be used, and therefore greater stability can be achieved at steady state, resulting in greater reliability.

Claims (1)

[Claims] 1. When bonding the glass barrel and end cap of a tubular fuse with an adhesive, the adhesive includes (1) an epoxy resin and (2) an epoxy compound containing a dialkylamine (an alkyl group). It is recommended to use a one-component thermosetting epoxy resin composition consisting of a latent curing agent obtained by treating the powder surface of an addition compound obtained by reacting a compound (which may be substituted) with an acidic substance. A manufacturing method for a characteristic tube-shaped fuse. 2. When bonding the glass barrel and end cap of a tubular fuse with an adhesive, the adhesive is (1) an epoxy resin and (2) an epoxy compound containing dialkylamine (even if the alkyl group is substituted). Using a one-component thermosetting epoxy resin composition consisting of a latent curing agent obtained by treating the powder surface of an addition compound obtained by reacting (good) with an acidic substance, and (3) an imide compound. A method for manufacturing a tubular fuse characterized by: