JP2624998B2 - Guide sheave - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a guide sheave, and more particularly to a guide sheave that can be suitably used for a wire enamelling device.

<Conventional technology> With the recent development of the electronics field, the copper wire of the magnet wire used for precision equipment, acoustic equipment, measuring equipment, control equipment, etc., has become increasingly thin, from ultra-fine wires (0.05 to 0.03 mm). It is shifting to ultra-fine wires (0.01-0.03mm). Such a copper wire is usually provided with an insulating enamel coating, and various problems occur with respect to a guide sheave used in a wire enamelling device used for the coating, particularly a guide sheave used in a baking process. I have.

Conventionally, as the above-mentioned guide sheave, precise workability,
Aluminum is generally used from the viewpoint of weight reduction and heat resistance, and the sieve is further coated with a fluororesin to prevent damage to copper wire and enamel coating and corrosion due to contact with the enamel varnish. Have been.

However, as described above, the wire diameter of the copper wire becomes extremely thin,
Further, from the viewpoint of productivity, as the linear velocity in the enamelling device increases, disconnection of the copper wire due to the guide sheave increases. This is because the wire diameter of the copper wire is small and the wire speed at the time of coating is fast, so the fluororesin film coated on the guide sheave is significantly worn and damaged, or the copper wire is wrapped by static electricity charged on the fluororesin film It is due to. Further, when the copper wire wound around the sheave due to the disconnection is removed, the coated fluorine resin film and the sheave itself are damaged, and a vicious cycle of causing the disconnection is repeated.

In addition, since aluminum sheaves have a relatively large specific gravity of about 2.7, a torque higher than the tensile strength is applied to the copper wire, which may cause disconnection, or the weight of the sheave itself may apply a load to the bearing fitted in the sheave, causing the copper wire to rotate. There are problems such as defects and shortening of the life of the bearing.

<Problems to be Solved by the Invention> As described above, the guide sheave used in the wire enamelling process is used under a severe environment, and particularly in the baking process, the disconnection of the copper wire frequently occurs, and the yield is poor.
Complicated work such as restoration of the line from the disconnected state, replacement of the sheave, and re-fluorine coating of the sheave was required, and it was hardly possible to say that the productivity was good.

In recent years, ceramic sheaves with improved abrasion resistance of the sheave itself and plastic sheaves with reduced weight have been proposed as alternatives, but the former is used for copper wire abrasion, sheave abrasion, and enamel paint. Of the wear material may occur. Also, higher specific gravity than aluminum (about 3.3)
Therefore, a large torque is easily applied to the copper wire, and the sheave itself is easily broken. On the other hand, the latter plastic sieve improves the above-mentioned problems, but does not have heat resistance or chemical resistance. Therefore, it is difficult to use it in a process requiring such characteristics, and in particular, wire enamelling. It is unsuitable for a baking process using an apparatus.

SUMMARY OF THE INVENTION An object of the present invention is to provide a guide sheave having excellent characteristics in which the above-mentioned problems of conventional guide sheaves made of aluminum, ceramic and plastic are improved.

<Means for Solving the Problems> The inventors of the present invention have conducted intensive studies to achieve the above object, and found that when a guide sheave molded using a polyimide resin is used in a wire enamelling device, heat resistance is reduced. It has been found that the present invention has excellent properties and chemical resistance, and that the disconnection of the copper wire is reduced and the productivity is improved, and the present invention has been completed.

That is, the guide sheave of the present invention is obtained by molding a mixture of a polyimide resin obtained by reacting a tetracarboxylic dianhydride and a diamine component, and a conductive filler, and in particular, a conductive filler. The guide sheave formed in this manner is a preferred embodiment for preventing electrification due to static electricity.

The polyimide resin used for the guide sheave of the present invention is an engineering plastic excellent in heat resistance and chemical resistance, and practically an acid component such as aromatic tetracarboxylic dianhydride and a diamine component such as aromatic diamine. It is preferable to use a wholly aromatic polyimide resin obtained by imidizing a polyamic acid obtained by reacting Such aromatic tetracarboxylic dianhydrides include, for example, pyromellitic acid, 3,3 ', 4,4'-biphenyltetracarboxylic acid, 2,3,3', 4'-biphenyltetracarboxylic acid, 1 , 2,4,5-naphthalenetetracarboxylic acid, 1,
2,5,6-naphthalenetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 2,2-bis [4- (2, 3-dicarboxyphenoxy) phenyl] propane, 4,4'-bis (2,3
-Dicarboxyphenoxy) dianhydrides of tetracarboxylic acids such as diphenyl ether, oxides thereof, lower alkyl esters, polyhydric alcohol esters and the like, and these may be used alone or in combination of two or more. . In the present invention, the aromatic tetracarboxylic dianhydride is partially converted to an arbitrary amount of an aliphatic tetracarboxylic dianhydride such as 1,2,3,4-butanetetracarboxylic dianhydride. It can also be used after substitution.

Examples of the aromatic diamine to be reacted with the aromatic tetracarboxylic dianhydride include 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminodiphenyl ether, and 3,3'-dimethoxy. -4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, diphenylether diamines such as 3,4'-diaminodiphenyl ether or diphenylthioether diamines such as thioethers thereof, 4,
4'-diaminobenzophenone, 3,3'-dimethyl-4,
Benzophenone diamines such as 4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane Diphenylmethane diamine, 2,2'-bis (4-aminophenyl) propane, 2,2'-bis (3
Bisphenylpropane-based diamines such as -aminophenyl) propane, diphenylsulfoxide-based diamines such as 4,4'-diaminodiphenylsulfoxide and 3,3'-diaminodiphenylsulfoxide, 4,4'-diaminodiphenylsulfone, and 3,3 ' -Diphenylsulfone diamines such as diaminodiphenylsulfone, benzidine,
Biphenyl diamines such as 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 3,3'-diaminobiphenyl, 2,6-diaminopyridine, 2,5-diaminopyridine, 3,4-diaminopyridine and the like 4,4′-di (m-aminophenoxy) diphenylsulfone, 4,4′-di (p-amino) such as pyridine-based diamine, o-, m- or p-diaminobenzene, 3,5-diaminobenzoic acid, etc. Phenoxy) diphenyl sulfone, 4,4'-di (m-aminophenoxy) diphenyl ether, 4,4'-di (p-aminophenoxy) diphenyl ether, 4,4'-di (m
-Aminophenoxy) diphenylpropane, 4,4'-di (p-aminophenoxy) diphenylpropane, 4,4 '
-Di (m-aminophenylsulfonyl) diphenyl ether, 4,4'-di (p-aminophenylsulfonyl) diphenyl ether, 4,4'-di (m-aminophenylthioether) diphenylsulfide, 4,4'-di (P-
Aminophenyl thioether) diphenyl sulfide,
4,4'-di (m-aminophenoxy) diphenyl ketone, 4,4'-di (p-aminophenoxy) diphenyl ketone, 4,4'-di (m-aminophenoxy) diphenylmethane, 4,4'-di (P-aminophenoxy) diphenylmethane, 2,5-diaminotoluene, 2,4-diaminoxylene, diaminodurene, 1,5-diaminonaphthalene,
2,6-diaminonaphthalene and the like. These diamines may be used alone or in combination of two or more. In addition, the aliphatic diamine may be used by substituting a part of the aromatic diamine.

Examples of the organic polar solvent serving as a reaction solvent between the aromatic tetracarboxylic dianhydride and the aromatic diamine include N-methyl-2-pyrrolidone, dimethylacetamide, dimethylformamide, dimethylsulfoxide, hexamethylenephosphortriamide, pyridine and the like. And phenols such as cresol, phenol and xylenol. In addition, an organic solvent such as hexane, benzene, toluene, xylene, or alcohol may be used in combination with the above solvent.

Although the guide sheave of the present invention is formed by molding the polyimide resin obtained as described above as a main component, the resin is preferably obtained in a powder state from the viewpoint of moldability. The polyimide powder can be obtained, for example, by the following method.

Aromatic tetracarboxylic dianhydride is gradually added to a solution of an aromatic diamine and an organic polar solvent (diamine concentration of 1 to 30 mol%, preferably 5 to 10 mol%), and the reaction is gradually progressed. Synthesize polyamic acid. Next, while stirring, for a relatively short time, for example, at a heating rate of about 10 ° C./min.
The temperature is raised to a temperature of 0 to 250 ° C., and while the condensed water accompanying the imide conversion is removed from the reaction system, an imidization reaction is gradually performed to precipitate polyimide particles to obtain a slurry-like polyimide solution. After cooling the obtained slurry-like solution, filtration, washing,
The desired polyimide powder is obtained by drying.

The guide sheave of the present invention is mainly composed of a polyimide resin, and other resins within a range that does not impair properties such as heat resistance and chemical resistance of the polyimide resin, for example, as a thermoplastic resin, polyethylene, vinyl chloride resin, polystyrene, Polypropylene, methacrylic resin, urea resin, melamine resin, ABS resin, polyacetal, nylon resin, polycarbonate, polyethylene terephthalate,
Contains polybutylene terephthalate, polyphenylene oxide, polyphenylene sulfide, polysulfone, fluorine resin, polyamide imide, polyamide bismaleimide, polyoxybenzylene, olefin vinyl alcohol copolymer, polyether sulfone, polyarylate, etc. As resin, urea resin,
Melamine resin, phenolic resin, unsaturated polyester,
It can be obtained by blending an epoxy resin, a diallyl phthalate resin, a silicon resin, a bismaleimide triazine resin, and the like, and molding by any molding means such as compression molding.

In a preferred embodiment of the guide sheave of the present invention, a conductive filler is blended. The guide sheave obtained by blending the conductive filler with the polyimide resin does not carry static electricity on the sheave itself because it has conductivity, and as a result, it has frequently occurred in the case of enamel coating on ultrafine copper wire Breakage due to winding of the copper wire around the sheave is eliminated.

Such a conductive filler may be previously blended during the synthesis of the polyimide powder. In this case, a powder having a structure in which the filler is used as core particles and coated with a polyimide resin is obtained. Needless to say, the conductive filler may be blended with the polyimide resin powder before molding so as to be uniformly dispersed.

Specific examples of the conductive filler include, for example, carbon black, graphite, silver powder, copper powder, aluminum powder,
Nickel powder, titanium powder, carbon fiber, etc.,
These may be used alone or in combination of two or more.
The compounding amount of the conductive filler is preferably such that the volume resistance of the obtained guide sheave is 10 to 10 ¹⁰ Ω · m from the viewpoint of preventing electrostatic charging, and the polyimide resin is 50 to 95% by volume.
It is effective to use a guide sheave formed by molding a composition consisting of 5% by volume and 5% by volume of a conductive filler. If the amount of the filler is less than 5% by volume, the volume resistance increases and the antistatic effect becomes insufficient. If the amount exceeds 50% by volume, the antistatic effect is sufficient but the mechanical strength of the guide sheave decreases. And inferior in durability. Further, the sheave surface becomes rough due to the influence of the filler, and the sliding characteristics of the sheave are hindered.

In the guide sheave of the present invention, other fillers such as molybdenum disulfide, boron nitrate, powder such as fluororesin, and glass fiber, aramid fiber, boron fiber, and phenol for improving creep characteristics are used as fillers for improving sliding characteristics. Fiber, silica-alumina fiber, steel and steel alloy fiber,
Fibers or whiskers such as silicon carbide whiskers, glass beads, ceramic, alumina,
Powders such as silicon oxide and silicon carbide, alumina, silica, mica, bronze, aluminum powder, copper powder, silver powder, nickel powder, etc.
It can be blended to the extent that the sliding characteristics are not impaired. These fillers are preferably mixed with a part of the conductive filler compounding amount, that is, at least one kind of the filler is used as a mixture within a range that the total amount of the conductive filler does not exceed 50% by volume. preferable.

<Effect of the Invention> Since the guide sheave of the present invention obtained as described above is molded using a polyimide resin as a main component, the specific gravity is 1.
It is extremely small, 35 to 1.95, and is lightweight. When used in the wire enamelling process, the torque applied to the copper wire is reduced, and the frequency of disconnection is reduced. Further, when the conductive filler is filled, an antistatic effect can be provided, and disconnection due to entanglement of the copper wire due to charging of the guide sheave can be prevented.

Further, by filling the filler, the wear resistance of the guide sheave itself is improved, and the wear is small even in high-speed enamelling, and the durability is excellent.

Therefore, when enamel coating of a copper wire is performed using the guide sheave of the present invention in a wire enamelling device, in severe environments, for example, disconnection, sheave wear, and damage occurring even in a baking process are reduced, and productivity is reduced. It will improve.

<Example> Hereinafter, an example of the present invention will be shown and specifically described.

Examples 1 to 3 Four-necked flasks were added with approximately equimolar amounts of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and 4,4'-diaminodiphenyl ether. A solution in which graphite was dispersed in N-methyl-2-pyrrolidone by means of a ball mill was added as shown in Table 1 and uniformly mixed by heating with stirring.

Then, when the temperature was raised and heating was continued, water produced as a by-product at the time of dehydration and ring closure of the polyamic acid in a temperature range of 170 to 175 ° C. began to be distilled out, and the contents began to suddenly become cloudy. Then, the polyimide particles were precipitated in the form of slurry using graphite as a core.

Thereafter, the temperature was further raised to 190 ° C., and the polymerization reaction was continued for 2 hours. Next, after terminating the polymerization reaction, the reaction solution was cooled, and a polyimide composite powder having a structure in which a filler was coated with a polyimide resin was isolated by filtration. Next, the obtained powder was washed twice with N-methyl-2-pyrrolidone and finally further twice with acetone. And
After this series of washings, the polyimide composite powder was dried by heating at 250 ° C. for 3 hours to obtain the desired polyimide composite powder.

Comparative Examples 1 and 2 A polyimide composite powder was obtained in the same manner as in Example except that the composition shown in Table 1 was followed.

The obtained polyimide powder is compressed at a pressure of 1000 kg / cm ^{2 at a} temperature of 40.
Heat compression molding was performed at 0 ° C. for a compression time of 30 minutes to produce a polyimide molded body.

The molded body obtained in this manner was turned on a lathe, processed to the dimensions shown in the drawing to form a guide sheave, fitted with a mini bearing (NMBL-1040ZZ), and used as a guide sheave for the printing process of a wire enamelling device for extra fine wires. did.

Various guide sheaves having the physical properties shown in Table 1 were evaluated as Comparative Examples 3 to 7 and evaluated as follows.

The guide sheave obtained in each of the examples and comparative examples was attached as a guide sheave of a wire enamelling device for extra fine wires (manufactured by Hisahara Seisakusho) to determine whether or not winding due to static electricity was generated, the degree of sheave damage (abrasion resistance), and bearings. The frequency of replacement, disconnection frequency, and operation rate of the apparatus were examined, and the results are shown in Table 1.

 The drawing conditions are as follows.

Wire diameter 0.015 ~ 0.05mmφ, wire speed 300 ~ 350m / min, enamel coat thickness 3 ~ 7μm, number of coating 15 times, operation time 3 months, guide sheave atmosphere temperature 200 ℃ As is clear from the results in Table 1, the guide sheave of the present invention has excellent heat resistance (250 ° C. or higher) and strength, and is used, for example, as a guide sheave in the printing process of an enamelling device for extra fine wires. It can be seen that the material is durable enough to be used, and has excellent durability which is not affected by the solvent even when exposed to a solvent such as an enamel varnish.

Furthermore, the guide sheave of the present invention, by including a conductive filler in a specific amount so that the volume resistance value is in a specific range, can be provided with antistatic properties, disconnection due to winding of the copper wire due to charging is reduced, It turns out that it is especially effective for high-speed enamelling operation.

[Brief description of the drawings]

The drawings show the dimensions of the guide sheave produced in the example of the present invention.

Claims (2)

(57) [Claims] 1. A guide sheave formed by molding a mixture of a polyimide resin obtained by reacting a tetracarboxylic dianhydride with a diamine component and a conductive filler. 2. The guide sheave according to claim 1, wherein a mixture comprising 50 to 95% by volume of a polyimide resin and 5 to 50% by volume of a conductive filler is molded.