JP2013142575A - Adhesive composition for clock rotor, manufacturing method for clock rotor using the same, and clock rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition for a clock rotor and a clock rotor using the same in which no outflow of an adhesive to a shaft occurs, a step for cleaning components can be eliminated, component structures are simple, production steps are simple with a hardening step of one time thermal hardening that fixes the rotor and the shaft together, and shipping of defective components can be prevented by checking an adhesive with high visibility when an adhesive sticks to a portion in no need.SOLUTION: The clock rotor having a rotor magnet and a rotor shaft is manufactured using the adhesive composition for a clock rotor that includes bisphenol F-type diglycidyl ether as a main agent, 1,3-bis(hydrazino carboxylate ethyl)-5-isopropyl hydantoin, carbon black, fumed silica, and 2-ethyl-4-methylimidazole.

Description

The present invention relates to an adhesive composition for a timepiece rotor and a timepiece rotor part, and more particularly to an adhesive composition for fixing a rotor magnet and a rotor shaft used in a timepiece and a timepiece rotor using the same.

An electronic timepiece called an analog quartz timepiece has many components such as a gear, an electronic circuit, a battery, and a dial on the inside. As a transmission system for moving the needle, a rotor, which is a magnetic gear, rotates 180 degrees once per second. This movement changes from the fifth car to the fourth car (with the second hand attached) → the third car → the central car (with the minute hand attached) → the minute wheel → the hour wheel (with the hour hand attached) We tell in order and display time.
The rotor which becomes a driving force is made by attaching a rotor magnet made of a bond magnet to a rotor shaft.

As a method of attaching a rotor magnet to a rotor shaft, for example, in Patent Document 1, in a rotor wheel of a clock motor that passes through a rotor shaft at the center of the rotor magnet and rotates around the rotor shaft, an axis is provided on the outer periphery of the rotor shaft. There has been proposed a rotor vehicle in which a plurality of directional grooves are provided, adhesive is put therein, and the rotor is attached to the outer periphery.
This adhesive is an anaerobic adhesive, which is poured between the rotor shaft and the rotor magnet, but even if the adhesive protrudes, it does not harden immediately. There is.

Further, in Patent Document 2, a rotor for a step motor including a permanent magnet having a center hole and having a disk shape and a non-magnetic metal rotor true, the permanent magnet and the rotor true pass through a center hole of the permanent magnet. Thus, a rotor for a step motor characterized by being fixed with a thermosetting adhesive has been proposed.
In the present invention, the fitting portion of 1/100 to 3/100 mm between the rotor true and the rotor magnet is loosened and fixed with a thermosetting adhesive. There is no detailed description of the adhesive.

Patent Document 3 includes a step of filling an anaerobic curable composition having ultraviolet curable properties between a rotor and a shaft formed by laminating rotor iron pieces, and the anaerobic curable composition protruding from both ends of the rotor. There is disclosed a method for bonding a rotor and a shaft, characterized by comprising a step of forming a fillet portion by curing by ultraviolet irradiation and a step of completely curing an anaerobic curable composition at heating or room temperature.
In addition, Loctite 601 (manufactured by Nippon Loctite) is used as an anaerobic adhesive.

Japanese Utility Model Publication No. 4-47378 Japanese Utility Model Publication No. 1-123477 JP 61-48555 A

In Patent Document 1, an anaerobic adhesive is used to remove the protruding adhesive and complete the part. When such a method is adopted, there is a problem that not only the number of steps for cleaning the parts increases, but also the use of a solvent or the like increases the environmental load.
Further, if the excess adhesive remains without being removed by washing, the product is shipped with the adhesive attached to the gear portion. As a result, there is a problem that a defective timepiece such as a timepiece operation is stopped can be formed.

In Patent Document 2, in order to obtain a finished part by pouring a thermosetting resin into a gap between the shaft and the rotor to obtain a finished part, when the adhesive flows out at the time of heat curing, the shaft system and shape are deformed by the adhesion of the adhesive. Therefore, there is a problem that it becomes a defective part. In particular, if a large amount of adhesive is applied, flow-out occurs, so that it is very difficult to set the amount of application.
In addition, the groove for pouring the adhesive into the part has to be processed and molded, and there is a problem that the part processing process becomes complicated.

  In Patent Document 3, an adhesive having both ultraviolet curing and anaerobic curing is used, and the adhesive is poured into the shaft portion, and then first irradiated with ultraviolet rays to form a fillet and fixed, followed by main curing. Yes. Even if the proposed method is used, if the adhesive flows out before being irradiated with ultraviolet rays, the adhesive attached to the shaft part may deform the shape of the shaft, resulting in a defective part. Further, there is a problem that the manufacturing process becomes complicated because the curing process of ultraviolet irradiation and heat curing must be performed twice.

  In view of the above-described conventional problems, the present invention does not cause the adhesive to flow out to the shaft, does not have a step of cleaning the component, does not complicate the structure of the component, and performs the rotor in a single curing step of thermosetting. The watch rotor adhesive composition can be manufactured by a simple process that can fix the shaft and the adhesive can be confirmed with good visibility even when the adhesive is attached to an unnecessary part, and the watch rotor adhesive composition can be prevented. The purpose is to provide a watch rotor.

The adhesive for a watch rotor of the present invention comprises bisphenol F-type diglycidyl ether, 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin, carbon black, and fumed silica as main components. It is characterized by further containing 2-ethyl-4-methylimidazole.
Alternatively, the addition amount of 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin is 35 phr or more and 45 phr or less with respect to bisphenol F-type diglycidyl ether, or the amount of carbon black is The content of the fumed silica is 1.0 wt% or more and 2.5 wt% or less with respect to the total amount of the adhesive for the watch rotor. 5 wt% or more and 1.5 wt% or less.
Further, the timepiece rotor manufacturing method of the present invention comprises a small amount of adhesive on the portion of the bonding site 3 sandwiched between the rotor magnet 1 and the rotor shaft receiving plate 2-a. It is characterized in that it is manufactured by being applied and glued by heat curing.
The timepiece rotor of the present invention is characterized in that the timepiece rotor adhesive composition of the present invention is used in at least a timepiece rotor composed of a rotor magnet and a rotor shaft.

According to the present invention, the flow of adhesive to the shaft does not occur, there is no step for cleaning the component, the structure of the component is not complicated, and the rotor and the shaft are fixed in a single curing process. An adhesive composition for a watch rotor that can be manufactured in a simple process and that can be confirmed with good visibility even when the adhesive is attached to an unnecessary part, and a watch rotor using the same Can be provided.

It is sectional drawing of the timepiece rotor of this invention.

EXAMPLES Hereinafter, although this invention is demonstrated in detail with an Example, this invention is not limited only to an Example.

  The adhesive composition for watch rotors of the present invention comprises bisphenol F type diglycidyl ether, 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin, carbon black, and fumed silica as main components. Or further comprising 2-ethyl-4-methylimidazole.

Bisphenol F-type diglycidyl ether is used as the main ingredient of this material.
Examples of the monomer containing an epoxy group in the molecule include a solid epoxy resin at room temperature and a liquid epoxy resin. In consideration of manufacturability by adhesion of a watch rotor, an epoxy resin that is liquid at room temperature is most preferable from the viewpoints of applicability and transfer from a container.
The liquid epoxy resin is roughly classified into an epoxy resin having an alkyl group with an epoxy group and an epoxy resin containing an aromatic ring. Unlike a TV set that is used with a fixed timepiece, the watch is expected to be used in a car or on a sandy beach. Therefore, it is particularly necessary to consider heat resistance. For this reason, an epoxy resin having an aromatic ring in the molecule and a structure for improving heat resistance is preferable.

Moreover, since the hardened | cured material may be wash | cleaned at the time of a maintenance for timepiece parts, chemical resistance is required. Epoxy resins having an epoxy group include glycidylamine and glycidyl ether. In order to improve chemical resistance, glycidyl ether having an ether bond is advantageous.
On the other hand, since the adhesive for a watch rotor plays a role of fixing two metal parts, it is desired that a group having a polarity such as a hydroxyl group is present in the molecule. When a compound having an amino group (NH bond) (for example, 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin) is reacted with a curing agent used for curing the epoxy resin. Is advantageous from the viewpoint of adhesive strength because it generates a -C-N- bond while generating a hydroxyl group when an epoxy group reacts with an amino group. The bisphenol F-type diglycidyl ether used for the watch rotor adhesive of the present invention is obtained by reacting the raw material bisphenol F with epichlorohydrin. Since the component to produce | generate is also contained, it becomes further advantageous for an adhesive force improvement. In addition, bisphenol F-type diglycidyl ether has high molecular symmetry and has good toughness and heat resistance.

In addition, since the epoxy group curing reaction is a polyaddition reaction or ring-opening polymerization, the shrinkage of curing is less than that of other thermosetting resins, which is advantageous when manufacturing a timepiece rotor that requires high accuracy.
The ether bond that forms glycidyl ether has a moderate amount of free rotation chemically, so it shows some flexibility when it is made into a product. Will increase.

As bisphenol type diglycidyl ether, bisphenol A type, bisphenol AD type, bisphenol S type, etc. are also considered. Diglycidyl ether is the best. For example, the viscosity of liquid bisphenol A-type diglycidyl ether is 120 to 150 P at 25 ° C, whereas the viscosity of bisphenol F-type diglycidyl ether is 15 to 60 P at 25 ° C. Bisphenol F type diglycidyl ether is very advantageous. The epoxy equivalent of the bisphenol F-type diglycidyl ether used in the present invention is 160 to 175 (g / eq).

Examples of the curing agent that reacts with the epoxy group include amine-based, acid anhydride-based, and dicyandiamide. Among these, an amine curing agent is a curing agent that can be cured at a high speed for a short time.
As a property of the curing agent, when a liquid amine having a high curing rate is mixed, the reaction starts from the time of mixing, and thus a phenomenon that the pot life is shortened occurs. For this reason, it is conceivable to use a solid curing agent at room temperature and disperse it in an adhesive for a watch rotor to ensure storage stability. Examples of such a curing agent include an epoxyamine adduct type, solid imidazole, and dicyandiamide.

  The timepiece manufacturing process of the present invention is produced in a clean room. For this reason, you must avoid bringing in dust. On the other hand, when a powder hardener is used as the adhesive, there is a risk that the hardener (attached to the outside of the container, etc.) attached when the adhesive is manufactured is brought into the manufacturing site. For this reason, the hardening | curing agent which can remove powder by simple methods, such as water wiping, is suitable. 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin used in the sealant of the present invention is solid at room temperature, but is easily dissolved in water and has a high detergency (such as an epoxyamine adduct type is water-soluble). Not insoluble in alcohol.) Also, it has strong adhesive strength, has multiple NH bonds in one molecule, has high crosslink density, and has physical properties suitable for watch rotor adhesives with excellent heat resistance and solvent resistance (liquid crystal resistance). . Since it has this characteristic, it contains as a hardening | curing agent of the adhesive agent for timepiece rotors of this invention.

  The watch rotor adhesive of the present invention contains fumed silica. When the main agent is a liquid and the curing agent is a solid, the curing reaction may be microscopically uneven due to separation from differences in specific gravity during heat curing. Mixing fumed silica in the adhesive creates thixotropy in the adhesive. As a result, even if the liquid component in the adhesive is reduced in viscosity by heating, the solid component is difficult to move and separate, resulting in uneven curing. Reaction can be prevented. Since the watch rotor is a precision part and is a part incorporated in the watch, if there is an uncured portion due to non-uniform curing, the uncured liquid material vaporizes over time and contaminates other parts. For this reason, fumed silica is contained in the adhesive for a watch rotor.

  The watch rotor adhesive of the present invention contains carbon black. The purpose is to increase visibility effectively. In general, anaerobic adhesives and ultraviolet curable adhesives are often transparent. In particular, adhesives having ultraviolet curable properties are often transparent for the purpose of ensuring light transmittance. With such an adhesive, it is difficult to confirm the presence or absence of adhesion with the naked eye with a small part for a watch that cannot confirm the presence or absence of a gear without confirmation with a microscope. Therefore, the watch rotor adhesive of the present invention is blackened to improve visibility. Even if a drop of adhesive adheres to the target location, it is black so that it can be recognized immediately, and it is possible to prevent defective parts due to adhesion of the adhesive.

The watch rotor adhesive of the present invention may contain 2-ethyl-4-methylimidazole as a curing accelerator. Imidazole derivatives are used as epoxy resin curing agents and accelerators. Although many imidazoles are solid, 2-ethyl-4-methylimidazole that liquefies at room temperature is employed in the adhesive for a watch rotor of the present invention. This compound is dissolved and homogenized in bisphenol F-type diglycidyl ether. As a result, there is an effect that, when heat-cured, there is no occurrence of non-cured portions non-uniformly, and the whole can be completely cured.

  The adhesive having the above structure has an appropriate viscosity and does not flow out when applied. In addition, since the adhesive for a watch rotor of the present invention has a high adhesive force and does not need to be applied in such an amount that it flows out, the rotor magnet and the rotor shaft can be fixed with a small amount of adhesive. There is no protrusion and no cleaning is required.

  The addition amount of 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin of the present invention is preferably 35 phr or more and 45 phr or less with respect to bisphenol F-type diglycidyl ether. If it is less than 35 phr, the curing time is long, or it is uncured and cannot be used. Moreover, when added over 45 phr, a viscosity will become high too much, workability | operativity when apply | coating a suitable quantity to components will fall, and it cannot endure use. As a result, the amount of 35 phr or more and 45 phr or less is the optimum amount.

The amount of carbon black is not limited as long as visibility can be ensured, but the watch rotor adhesive of the present invention is contained in an amount of 1.0 wt% to 2.5 wt% with respect to the total amount.
If the amount is less than 1.0 wt%, the visibility is lowered and it is difficult to confirm the adhesive on the part. Conversely, if the amount is too large, the effect does not increase. % To 2.5 wt% is preferable.

The amount of fumed silica is desirably 0.5 wt% or more and 1.5 wt% or less with respect to the total amount of the adhesive for the watch rotor.
If the amount is less than 0.5 wt%, the effect of thixotropy will be reduced. Conversely, if the amount is too large, the viscosity of the adhesive will increase and the workability will decrease, and it will not be able to withstand use. For this reason, as a suitable quantity, 0.5 wt% or more and 1.5 wt% or less are preferable with respect to the whole quantity.

The amount of 2-ethyl-4-methylimidazole is preferably 0.6 wt% or less with respect to the total amount of the adhesive for the watch rotor. More preferably, it is 0.3 wt% or less.
When added over 0.6 wt%, there is storage stability for 5 days, and in the case of 0.3 wt%, there is storage stability for 7 days. If this period is exceeded, the viscosity of the adhesive increases and there is a problem in practical use.

Using the adhesive for a watch rotor of the present invention, a rotor magnet and a rotor shaft are bonded to obtain a watch rotor, and an adhesive is applied to a surface where the rotor magnet and the rotor shaft are in contact, and the adhesive is fixed while fixing the adhesive. By doing so, a watch rotor part can be obtained.
Specifically, FIG. 1 shows a cross-sectional view of the timepiece rotor of the present invention. The rotor magnet 1 has a cylindrical shape with a hole in the center. The rotor shaft 2 includes a shaft 2-a for receiving a rotor magnet, in addition to a shaft serving as a guide when the timepiece rotor rotates. In order to obtain a finished watch rotor, a small amount of adhesive is applied to the rotor magnet 1 and the portion of the bonding portion 3 sandwiched between the rotor shaft receiving trays 2-a, and they are fitted and heat-cured to bond the watch rotor. obtain.

(Example)
(A) Bisphenol F-type diglycidyl ether (epoxy equivalent is 160 to 175 (g / eq) and viscosity at 25 ° C. is 15 to 60 P), and (B) 1,3-bis (hydrazinocarboethyl) -5 Isopropyl hydantoin, (C) carbon black, (D) fumed silica, and (E) 2-ethyl-4-methylimidazole were prepared.

(A) with respect to (A), 10 phr, 35 phr, 40 phr, 45 phr, 55 ph
In the mixture of r, (C) carbon black was mixed with 2 wt% of the total amount, and (D) fumed silica was mixed with 1 wt% of the total amount to obtain a rotor adhesive.
A small amount of adhesive is applied to the rotor magnet 1 shown in the figure and the part of the adhesion part 3 sandwiched between the rotor shaft trays 2-a, and the adhesive is fitted and cured by heating (120 ° C. for 60 minutes). Created.
As a result, when the adhesive strength was 10 phr, it was not possible to obtain a watch rotor that could be used with a fixing strength of 5 N or less and a low hardness of the adhesive. In the case of 35 phr to 45 phr, the fixing force was 7 to 8 N, exceeding the standard value of 5 N, and a watch rotor usable for a watch could be obtained. Moreover, when the protrusion of the adhesive was confirmed, there was no protrusion in any case. In the case of 55 phr, the viscosity of the adhesive was increased, the workability was poor and an appropriate amount could not be applied, and a watch rotor could not be produced.
From the above, it was found that the addition amount of 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin is preferably 35 phr or more and 45 phr or less with respect to bisphenol F-type diglycidyl ether.

A mixture of (A) with 40 phr of (B), (D) 1 wt% of the total amount of fumed silica, and (C) carbon black with a total amount of 0.1, 1.0, 2.0, 2 .5 and 5.0 wt% were mixed to obtain a rotor adhesive.
Next, this adhesive was adhered to the upper surface of the rotor magnet and cured at 120 ° C. for 60 minutes to confirm the visibility. As a result, in the case of 0.1 wt%, the visibility was inferior and it was difficult to determine the presence or absence of the adhesive, but in the case of 1.0 wt% or more, the visibility was good in any case and the adhesive was not protruding. In this case, it was found that it was easy to judge the defect. However, the visibility of 2.5 wt% and 5.0 wt% was almost the same.
From the above results, it was found that the amount of carbon black is preferably 1.0 wt% or more and 2.5 wt% or less with respect to the total amount.

(B) is mixed with 40 phr to (A), (C) 2.0 wt% of the total amount of carbon black, and (D) fumed silica is the total amount of 0.1, 0.5, 1.0. , 1.5, and 3.0 wt%, respectively, to obtain a rotor adhesive.
A small amount of adhesive is applied to the rotor magnet 1 shown in the figure and the part of the adhesion part 3 sandwiched between the rotor shaft trays 2-a, and the adhesive is fitted and cured by heating (120 ° C. for 60 minutes). Created.
When the obtained timepiece rotor was disassembled and the cured state was observed with a microscope, uniform curing was partially observed in the adhesion site in the case of 0.1 wt%. In the case of 0.5 or more and 1.5 wt% or less, it was cured uniformly in any case, the strength was 7 to 8N of 5N or more, and a good watch rotor could be obtained without protrusion.
From the above, it has been found that the amount of fumed silica is preferably 0.5 wt% or more and 1.5 wt% or less with respect to the total amount of the adhesive for the watch rotor.

(B) mixed with 40 phr to (A), (C) 2.0 wt% of the total amount of carbon black, (D) 1.0 wt% of the total amount of fumed silica, (E) 2− Ethyl-4-methylimidazole was mixed so that the total amount would be 0, 0.3, 0.6, and 0.9 wt% to obtain a rotor adhesive.
A small amount of adhesive is applied to the rotor magnet 1 shown in the figure and the part of the adhesion part 3 sandwiched between the rotor shaft trays 2-a, and the adhesive is applied by heat-curing (120 ° C., 50 minutes) to attach the watch rotor. Created.
As a result, the adhesive strength was 8N at 0 wt%, 10N at 0.3 wt%, 11N at 0.6 wt%, and 16N at 0.9 wt%.
Moreover, when this adhesive was left at the work site and the pot life was measured, under conditions of room temperature around 25 ° C. for 7 days, 0.6 wt% and 0.9 wt% adhesive increased in viscosity and could not be used. became. However, in the case of 0.3 wt% or less, it was found that almost no increase in viscosity was observed, and it could be used satisfactorily. In addition, at 0.6 wt%, it was found that the viscosity increase is small when left for 5 days and can be used well within 5 days. It was also found that the addition of (E) has the effect of increasing the adhesive strength and improving the component performance.
From the above, it was found that the amount of 2-ethyl-4-methylimidazole was 0.6 wt% or less, more preferably 0.3 wt% or less, based on the total amount of the adhesive for the watch rotor.

DESCRIPTION OF SYMBOLS 1 Rotor magnet 2 Rotor shaft 2-a Receptacle 3 Adhesion site

Claims (7)

An adhesive composition for a watch rotor comprising bisphenol F-type diglycidyl ether, 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin, carbon black, and fumed silica as main ingredients. Furthermore, 2-ethyl-4-methylimidazole is contained, The adhesive composition for timepiece rotors of Claim 1 characterized by the above-mentioned. The amount of 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin added is 35 phr or more and 45 phr or less with respect to bisphenol F-type diglycidyl ether. Adhesive composition for watch rotors. 3. The watch rotor adhesive according to claim 1, wherein the amount of carbon black is 1.0 wt% or more and 2.5 wt% or less with respect to the total amount of the watch rotor adhesive. Composition. The amount of fumed silica is 0.5 wt% or more and 1.5 wt% or less with respect to the total amount of the adhesive for watch rotors, The adhesive composition for watch rotors of Claim 1 or Claim 2 characterized by the above-mentioned. . An adhesive composition for a timepiece rotor according to any one of claims 1 to 5 is applied to a portion of an adhesion portion sandwiched between a rotor magnet and a receiving tray of a rotor shaft, and is adhered and bonded by heat curing. A method for manufacturing a rotor for a watch. A timepiece rotor having at least a rotor magnet and a rotor shaft, wherein the timepiece rotor adhesive composition according to any one of claims 1 to 5 is used.

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