JP2004099886A - Adhesive composition for precision part, dial for timepiece using the same, and method for manufacturing dial for timepiece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition for precision parts which excels in room temperature storability, low-temperature curability, flowability, and adhesive properties. <P>SOLUTION: The adhesive composition for precision parts comprises a main agent (A) composed of a bisphenol A type epoxy resin and/or a bisphenol F type epoxy resin, an amine curing agent (B) which is solid at normal temperatures, has a softening point of 90-120°C, and an average particle diameter of ≤6 μm, and an ultrafine particulate silica (C), and the amount of the amine curing agent (B) incorporated is 1.5-2.5 times the chemical equivalent weight of the main agent (A), and the amount of the ultrafine particulate silica incorporated is 0.5-2.0 pts.wt. based on 100 pts.wt. the main agent (A). <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an adhesive composition for bonding precision parts and a timepiece dial using the same. More specifically, the present invention relates to an adhesive composition for bonding a plant to a dial base, and a timepiece dial using the adhesive composition to bond a plant to a base. The present invention also relates to a method for manufacturing the timepiece dial.

Analog timepieces are usually equipped with a dial as shown in FIG. The timepiece dial 1 has a plant 2 bonded to a base 11. Examples of the plant 2 include decorative characters such as a time character 21 for indicating time, a window frame 22 of a date display window, a logo mark 23, and a decorative stone used as needed.

(2) A method of bonding the plant 2 to the base 11 will be described with reference to FIGS. As shown in FIG. 3, the feet 21a of the hour character 21 are inserted into the holes 11a formed in the timepiece base 11 from the front side of the base 11, and the hour character 21 is fitted into the dial base 11. Next, the feet 21a of the hour character 21 are caulked from the back side of the base 11, and the hour character 21 is temporarily fixed. Here, “crimping” means that a nail or a metal fitting that is fitted into the joint is hit or tightened with a tool to firmly secure the joint.

Thereafter, a solution obtained by dissolving a rubber-based adhesive in an organic solvent is injected from the back side of the base 11 using a dispenser or the like to diffuse the adhesive to the bonding site. The time character 21 is adhered to.

(4) In such a conventional bonding method, since an organic solvent is used, there has been a problem that the timepiece dial is discolored by the organic solvent. Further, there is a problem that the rubber-based adhesive deteriorates with time and the adhesive strength is reduced. As a result, there is a problem that when a shock is applied to a watch that has been used for a long time, the plant is detached from the base. In order to solve this problem, a method has been adopted in which the size of the plant is reduced so that the plant does not detach even when an impact is applied to the timepiece. In addition, a method of manufacturing a timepiece dial by attaching an adhesive seal to a thin plate-shaped plant and attaching the sticker to a substrate has been adopted (Patent Document 1).

However, these methods do not improve the adhesion between the plant and the substrate, but only prevent the detachment by impact. In addition, the workability is poor because the plant is small, and there is still a problem that the larger plant is still detached from the substrate. Furthermore, a dial using a small plant or a thin plate-shaped plant has a problem that it is inferior in three-dimensional appearance, texture and luxury.

(5) In the conventional bonding method, since the feet of the plant are caulked, the length of the feet of the plant is important, and it is necessary to maintain the dimensional accuracy of the feet.

On the other hand, conventionally, various epoxy resin adhesives using an amine compound as a curing agent have been known. For example, Patent Literature 2 describes a one-part adhesive for forming an electronic circuit including a bifunctional epoxy resin, an amine adduct-based curing agent, a thixotropic agent, an inorganic filler, and an organic pigment. However, this adhesive has a high thixotropic property, and has insufficient fluidity to inject the adhesive into the gap between the precision parts and to diffuse the adhesive to the bonding site. Further, this adhesive has a problem that the curing time is very short and the adhesive is cured before the adhesive is sufficiently diffused.
JP-A-6-161597 JP-A-7-133474

The present invention is intended to solve the problems associated with the prior art as described above, and has excellent storage stability at room temperature, can be cured at a relatively low temperature, and has excellent fluidity and adhesiveness. Another object of the present invention is to provide an adhesive composition for precision parts. Another object of the present invention is to provide a method of manufacturing a timepiece dial that can adhere a plant to a dial base without caulking. Furthermore, it is another object of the present invention to provide a timepiece dial that does not degrade the adhesive even after long-term use, maintains a sufficient adhesive strength, and does not allow a plant to be detached from the dial base. .

The present inventors have intensively studied to solve the above problems, and an epoxy resin adhesive composition containing a hardening agent having a specific softening point and a particle size and ultrafine silica in a specific ratio has a room temperature storability. , Low temperature curability, fluidity and adhesiveness, and completed the invention.

That is, the adhesive composition for precision parts according to the present invention,
(A) a main agent comprising a bisphenol A type epoxy resin and / or a bisphenol F type epoxy resin;
(B) an amine-based curing agent which is solid at ordinary temperature and has a softening point of 90 to 120 ° C. and an average particle size of 6 μm or less;
(C) an adhesive composition for precision parts containing ultrafine silica particles,
The amine-based curing agent (B) is contained in an amount of 1.5 to 2.5 times the chemical equivalent to the main agent (A),
It is characterized in that the ultrafine silica (C) is contained in an amount of 0.5 to 2.0 parts by weight based on 100 parts by weight of the base material (A).

The amine-based curing agent (B) is preferably a reaction product of a bisphenol A type epoxy resin and / or a bisphenol F type epoxy resin with a polyamine.

In addition, the adhesive composition for precision parts according to the present invention preferably further contains 2,2-oxybis (5,5-dimethyl-1,3,2-dioxaborinane), and the content is preferably an amine-based adhesive. More preferably, the amount is 1 to 2 parts by weight based on 100 parts by weight of the curing agent (B).

The timepiece dial according to the present invention is obtained by bonding a plant to a dial base using the adhesive composition for precision parts.

The method for manufacturing a timepiece dial according to the present invention comprises:
(I) inserting the foot of the plant into the hole of the dial base of the watch from the front side of the base;
(II) injecting the adhesive composition for precision parts from the back side of the base into the hole of the base into which the foot of the plant is inserted;
(III) heating the substrate obtained in the step (II) to cure the adhesive, and fixing the plant to the surface of the substrate.

に よ っ て By using the adhesive composition for precision parts according to the present invention, even precision parts with low service temperatures can be bonded, and the precision parts can be firmly bonded without caulking.

According to the method for manufacturing a timepiece dial according to the present invention, a timepiece dial can be manufactured without impairing its appearance.

Furthermore, by using the timepiece dial according to the present invention, the plants do not detach even after long-term use, so that the need to repair the timepiece is reduced.

The adhesive composition for precision parts according to the present invention is a one-part adhesive composition containing a main component, an amine-based curing agent, and ultrafine silica.

(A) Main agent:
The adhesive composition for precision parts according to the present invention contains a bisphenol A epoxy resin and / or a bisphenol F epoxy resin as a main component.

The bisphenol A type epoxy resin used in the present invention includes a bisphenol A type epoxy resin used for an ordinary liquid epoxy resin adhesive, and a liquid at room temperature is preferable. Among such bisphenol A type epoxy resins, those having a viscosity at 25 ° C of 100 to 250P are more preferable.

In the present invention, commercially available products such as Epicoat 828 (manufactured by Japan Epoxy Resin), YD-128, and YD-8215 (all manufactured by Toto Kasei) can be used as the bisphenol A type epoxy resin.

The bisphenol F type epoxy resin used in the present invention includes a bisphenol F type epoxy resin used for an ordinary liquid epoxy resin adhesive, and a liquid at room temperature is preferable. Among such bisphenol F-type epoxy resins, those having a viscosity at 25 ° C. of 10 to 50 P are more preferable.

In the present invention, commercially available products such as Epicoat 806, Epicoat 807 (all manufactured by Japan Epoxy Resin Co., Ltd.) and YD-8170C (Toto Kasei Co., Ltd.) can be used as the bisphenol F epoxy resin.

(B) Amine-based curing agent:
The amine-based curing agent used in the present invention is solid at room temperature and has a softening point of 90 to 120 ° C. When the softening point is lower than 90 ° C., the preservability of the adhesive composition is lowered, such as curing of the adhesive composition at room temperature or an increase in viscosity. Even if a plant is adhered to a dial base using such an adhesive composition, sufficient adhesive strength cannot be obtained, and the plant may be detached from the base.

By the way, some precision parts have low heat-resistant temperature. For example, plants, substrates, and the like used in timepiece dials are discolored, deformed, and dissolved at high temperatures because their surfaces are printed with paint or the like. For this reason, when bonding precision parts such as timepieces, the curing temperature is usually preferably 120 ° C. or lower. When the amine-based curing agent (B) having a softening point exceeding 120 ° C. is used under such curing temperature conditions, the amine-based curing agent (B) does not melt, and the adhesive is not sufficiently cured. High bond strength is not obtained and the plant may detach from the substrate.

Although the softening point of the amine-based curing agent (B) used in the present invention is not problematic as long as it is equal to or lower than the curing temperature for the above reason, when an amine-based curing agent having a softening point at the same temperature as the curing temperature is used, There is a problem that it takes time until the curing agent is sufficiently melted, and the curing time of the adhesive becomes longer. For this reason, the amine-based curing agent (B) used in the present invention preferably has a softening point lower than the curing temperature. Specifically, when a bisphenol A type epoxy resin is used, the softening point is desirably 90 to 110 ° C, more preferably 90 to 100 ° C, and particularly preferably 90 to 95 ° C. When a bisphenol F type epoxy resin is used, since the curing time is slightly shorter than that of the bisphenol A type epoxy resin, the softening point is 90 to 110 ° C, more preferably 100 to 110 ° C, and particularly preferably 103 to 107 ° C. Things are desirable.

(4) The amine-based curing agent (B) used in the present invention has a center particle diameter of 6 μm or less, preferably 3 to 6 μm. When the center particle diameter of the amine-based curing agent exceeds 6 μm, the curing agent does not uniformly diffuse to the bonding site, and a part of the bonding site is uncured. For example, usually, a watch base and a plant are formed by injecting an adhesive composition into a gap between a foot of a plant inserted into a hole of the watch base and the base, and heating the base to bond the adhesive composition. After uniform diffusion to the site, the adhesive composition is cured. However, when a curing agent having a center particle diameter of more than 6 μm is used, the curing agent is not sufficiently diffused when the adhesive composition is uniformly diffused, resulting in a portion where the curing agent does not exist. As a result, the adhesive composition is not cured in a portion where no curing agent is present, and it is not possible to obtain a sufficient adhesive strength. That is, when the center particle diameter of the amine-based curing agent is within the above range, when the adhesive composition is diffused to the bonding site, the curing agent can be uniformly diffused together with the main agent, and as a result, sufficient adhesive strength is obtained. Can be obtained.

The amine-based curing agent (B) used in the present invention can be obtained by reacting the bisphenol A type epoxy resin and / or the bisphenol F type epoxy resin with a polyamine under polyamine excess conditions. The epoxy resin and the polyamine are mixed in a solvent such as dioxane and reacted by heating. After filtering and washing the obtained reaction product, the solid reaction product is pulverized using a pulverizer such as a jet mill, and the pulverized product is classified to obtain an amine-based cured product having a center particle diameter in the above range. Get the agent.

軟 The softening point of the amine-based curing agent (B) is determined by adjusting the types of the epoxy resin and the polyamine and their mixing ratio (weight ratio). For example, the mixing ratio of the epoxy resin and the polyamine is preferably 7 to 10 parts by weight of the polyamine to 1 part by weight of the epoxy resin.

Examples of the polyamine include aliphatic polyamines such as diethylenetriamine, triethylenetetramine, 3,9- (3-aminopropyl) -2,4,8,10-tetraoxaspiro (5,5) undecane;
Aromatic polyamines such as metaxylenediamine and diaminophenylmethane;
Dimer acid polyamide;
Tertiary amines such as tris (dimethylaminomethyl) phenol, 2-ethyl-4-methylimidazole;
Lewis acid complexes such as boron trifluoride ethylamine complex are exemplified.

イ In addition, imidazole may be added when producing the amine curing agent (B) used in the present invention. By adding imidazole, a faster-curing adhesive composition can be obtained. It is desirable to add 1 to 10 parts by weight, preferably 2 to 8 parts by weight of the imidazole to 1 part by weight of the epoxy resin.

Examples of the imidazole used in the present invention include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, and 2-phenylimidazole -4-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazolium trimellitate, 2,4-diamino-6- (2'-methylimidazolyl- (1 ' ))-Ethyl-s-triazine and the like.

The adhesive composition for precision parts according to the present invention contains the amine-based curing agent (B) in an amount of 1.5 to 2.5 times the chemical equivalent to the main agent (A). When the content of the amine-based curing agent is less than the above lower limit, the adhesive composition is not sufficiently cured, and a sufficient adhesive strength cannot be obtained. In particular, when bonding plastic precision parts, the adhesive composition often does not sufficiently cure because the plastic precision parts have poor heat transfer characteristics. On the other hand, when the content of the amine-based curing agent exceeds the above upper limit, the viscosity of the adhesive composition increases, and it becomes difficult to uniformly diffuse the adhesive composition to the bonding site. Further, when the content of the amine-based curing agent is in the above range, there is an advantage that it is possible to cope with various precision parts having different heat transfer characteristics.

(C) Ultrafine particle silica:
Examples of the ultrafine silica (C) used in the present invention include Aerosil and fumed silica. The average diameter of the primary particles of the ultrafine silica is usually 7 to 40 nm. Aerosil is obtained by hydrolyzing silicon tetrachloride at high temperature (flame). Fumed silica is obtained by oxidizing silane gas.

<< Examples of such ultrafine silica particles include commercially available products such as AEROSIL # 50, 130, 200, 300, R972, R974, RX200, RY200, R202, and TT600 (all manufactured by Nippon Aerosil Co., Ltd.).

The adhesive composition for precision parts according to the present invention contains 0.5 to 2.0 parts by weight of ultrafine silica (C) based on 100 parts by weight of the base material (A). When the content of the ultrafine silica particles (C) is in the above range, the adhesive composition exhibits appropriate thixotropic properties. When the adhesive composition containing no ultrafine silica (C) is heated, the viscosity of the epoxy resin decreases, so that the solid amine-based curing agent (B) precipitates and separates, and the homogeneity of the adhesive composition is improved. Although impaired, the adhesive composition containing ultrafine silica (C) can prevent sedimentation and separation of the amine-based curing agent (B) due to its thixotropic properties, and can maintain the homogeneity of the adhesive composition. it can. When the content of the ultrafine silica (C) is less than the lower limit, the thixotropic property is insufficient, and the amine-based curing agent (B) precipitates and separates. On the other hand, when the content of the ultrafine silica (C) exceeds the upper limit, the thixotropic property is too high, so that the adhesive composition does not flow, and the adhesive composition can be uniformly diffused to the bonding site. And the adhesive strength is reduced.

(D) additive:
The adhesive composition for precision parts according to the present invention can contain an additive (D), if necessary. For example, 2,2-oxybis (5,5-dimethyl-1,3,2-dioxaborinane) is contained in the adhesive composition for precision parts in order to prevent the viscosity of the adhesive composition from increasing due to long-term storage at room temperature. Can be done.

When an adhesive composition containing no 2,2-oxybis (5,5-dimethyl-1,3,2-dioxaborinane) is stored at room temperature for a long period of time, the adhesive composition is partially cured due to a low curing temperature. And the viscosity increases. On the other hand, in an adhesive composition containing 2,2-oxybis (5,5-dimethyl-1,3,2-dioxaborinane), 2,2-oxybis (5,5-dimethyl-1,3,2-dioxaborinane) is used. ) Adheres to the amine-based curing agent (B), hinders contact between the main agent (A) and the curing agent (B), and can suppress the curing reaction at room temperature. The curing agent (B) to which 2,2-oxybis (5,5-dimethyl-1,3,2-dioxaborinane) has adhered can react with the main agent when heated and melted.

It is preferable that 2,2-oxybis (5,5-dimethyl-1,3,2-dioxaborinane) is contained in an amount of 1 to 2 parts by weight based on 100 parts by weight of the amine-based curing agent (B). When the content of 2,2-oxybis (5,5-dimethyl-1,3,2-dioxaborinane) exceeds the above upper limit, a curing reaction is inhibited when the adhesive composition is cured by heating, and sufficient The bonding strength cannot be obtained. On the other hand, if it is less than the above lower limit, a sufficient curing suppressing effect cannot be obtained, and a long-term storage property may not be obtained.

<Adhesive composition for precision parts>
The adhesive composition for precision parts according to the present invention contains the main agent (A), an amine-based curing agent (B), ultrafine silica (C), and, if necessary, an additive (D). Adhesive composition.

(4) The adhesive composition for precision parts can be cured at a temperature of 120 ° C. or lower and has excellent storage stability at room temperature. In addition, since it exhibits high adhesive strength, it exhibits excellent adhesiveness and can be fixed to precision parts without caulking. Furthermore, it is excellent in fluidity and quick-curing property, and can adhere a precision part without protruding from an adhesion part. In particular, it is very effective when bonding an object such as a precision part to which an adhesive cannot be directly applied to the bonding portion. Specifically, it is effective when manufacturing a timepiece dial described later.

Further, the adhesive composition for precision parts and the cured product thereof according to the present invention do not discolor or deteriorate precision parts. For example, when the white dial for a watch is manufactured, the use of the adhesive composition for precision parts can prevent discoloration of the white dial for a watch due to the adhesive composition. Specifically, the adhesive composition for precision parts was adhered to the surface of a white dial for a watch (a surface of a brass flat plate having an uneven surface, which was nickel-plated and then covered with silver plating). Thereafter, the white dial was attached to a watch case, and a 100-hour sunshine weather test (temperature: 63 ° C., light amount: 300 W / m ² ) was performed. It can be 6 or less, preferably 4 or less.

Furthermore, since the cured product of the adhesive composition for precision parts according to the present invention does not deteriorate, precision parts can be bonded for a long period of time.

<Clock face>
A timepiece dial according to the present invention is obtained by bonding a plant to a dial base using the adhesive composition for precision parts. The adhesive strength at this time is preferably 1 kgf or more. When the adhesive strength is 1 kgf or more, the plant is firmly adhered to the dial base and does not detach.

In addition, in the timepiece dial according to the present invention, since the adhesive does not deteriorate, the plant and the watch base are adhered to each other for a long time, and the plant is not detached from the base.

<Manufacturing method of watch dial>
The timepiece dial according to the present invention can be manufactured by using the adhesive composition for precision parts, for example, by the following method (hereinafter, referred to as “manufacturing method 1”). The following manufacturing method will be described using a time-character plant as a plant, but the plant is not limited to this.

Step (I):
As shown in FIG. 3, the foot 21a of the hourly plant 21 is inserted into the hole 11a of the dial base 11 shown in FIGS. 2 and 3 from the front side of the base. At this time, caulking may be applied to the foot 21a of the plant, but by using the adhesive composition for precision parts according to the present invention, the plant 2 can be bonded to the base 11 without caulking. . Thereby, the step of caulking can be omitted, and it is not necessary to make the length of the foot of the plant strict, and quality control of the plant becomes easy.

Step (II):
The adhesive composition for precision parts is injected into the gap between the foot 21a of the plant and the substrate from the back side of the substrate obtained in the step (I). The amount of the adhesive composition to be injected at this time is appropriately determined depending on the size of the plant. The method for injecting the adhesive composition for precision parts is not particularly limited, and examples thereof include a method using a dispenser or a pin.

Step (III):
In step (II), after injecting the adhesive composition, the obtained substrate is heated. The heating temperature at this time is 120 ° C. or lower, preferably 90 ° C. to 110 ° C. When the heating temperature is lower than the lower limit, the adhesive composition does not cure, and the plant cannot be bonded to the substrate. If the heating temperature exceeds the upper limit, the watch base and the plant may be discolored or deteriorated.

加熱 The heating time is preferably 10 to 30 minutes. If the heating time is less than 10 minutes, the adhesive composition cannot be sufficiently cured, and if the heating time exceeds 30 minutes, the base and the plant may be discolored or deteriorated.

The heating device is not particularly limited as long as it can sufficiently cure the adhesive composition and does not cause discoloration or deterioration of the watch base or the plant. For example, an oven, a hot plate, and a hot air heating device Is mentioned.

と When the substrate obtained in the step (II) is put into the heating device set at the above temperature, the temperature of the substrate starts to rise. Due to this temperature rise, the viscosity of the adhesive composition decreases, the adhesive composition flows, and the adhesive composition diffuses to the bonding portion 11b. Thereafter, when the temperature of the substrate reaches the curing temperature, the adhesive composition is cured, and the hourly plant 21 is adhered to the dial substrate 11.

The timepiece dial according to the present invention can be manufactured by the above-mentioned manufacturing method 1. However, after directly applying the adhesive composition for precision parts to the bonding portion 11b of the plant, the plant is attached to the dial. It can also be manufactured by fitting the substrate into a base for heating and heating the base to adhere the plant to the base for the dial (hereinafter, referred to as "manufacturing method 2"). The method for applying the adhesive composition is not particularly limited, but includes a screen printing method.

製造 Of the above production methods 1 and 2, production method 1 is preferable. The timepiece dial obtained by manufacturing the timepiece dial according to the manufacturing method 1 does not protrude from the bonding site and does not erroneously apply the adhesive composition to portions other than the bonding site. The plant can be adhered to the dial base without impairing the appearance of the dial.

<Example>
Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the examples. First, raw materials used in Examples and Comparative Examples will be described.

<Main agent>
(Resin A)
Bisphenol A type epoxy resin (manufactured by Toto Kasei Co., Ltd., trade name: YD-128)
(Resin F)
Bisphenol F type epoxy resin (manufactured by Japan Epoxy Resin, trade name: Epicoat 806)
<Curing agent>
(Curing agent 1: softening point 90 ° C., central particle diameter 6 μm, chemical equivalent 20 phr)
1.0 part by weight of resin A, 10.0 parts by weight of diethylenetriamine, and 5.0 parts by weight of 2-ethyl-4-methylimidazole were dissolved in dioxane and reacted. The obtained reaction product was filtered, washed, pulverized by a jet mill, and then classified to obtain an amine-based curing agent 1 having a softening point of 90 ° C. and a central particle diameter of 6 μm. The chemical equivalent of the curing agent 1 to 20 parts by weight of the mixture of 50 parts by weight of the resin A and 50 parts by weight of the resin F was 20 parts by weight.

(Curing agent 2: softening point 100 ° C., central particle diameter 6 μm, chemical equivalent 20 phr)
Except that 10.0 parts by weight of diethylenetriamine and 5.0 parts by weight of 2-ethyl-4-methylimidazole were used instead of 9.5 parts by weight of diethylenetriamine and 3.0 parts by weight of 2-ethyl-4-methylimidazole. In the same manner as in the preparation of the curing agent 1, an amine curing agent 2 having a softening point of 100 ° C. and a central particle diameter of 6 μm was obtained. The chemical equivalent of the curing agent 2 to 20 parts by weight of the mixture of 50 parts by weight of the resin A and 50 parts by weight of the resin F was 20 parts by weight. The chemical equivalent of the curing agent 2 to 100 parts by weight of the resin A was also 20 parts by weight.

(Curing agent 3: softening point 110 ° C., central particle diameter 6 μm, chemical equivalent 20 phr)
Except that 10.0 parts by weight of diethylenetriamine and 5.0 parts by weight of 2-ethyl-4-methylimidazole were used instead of 8.0 parts by weight of diethylenetriamine and 7.0 parts by weight of 2-ethyl-4-methylimidazole. In the same manner as in the preparation of the curing agent 1, an amine curing agent 3 having a softening point of 110 ° C. and a central particle diameter of 6 μm was obtained. The chemical equivalent of the curing agent 3 to 20 parts by weight of a mixture of 50 parts by weight of the resin A and 50 parts by weight of the resin F was 20 parts by weight.

(Curing agent 4: softening point 120 ° C., central particle diameter 6 μm, chemical equivalent 20 phr)
Except that 10.0 parts by weight of diethylenetriamine and 5.0 parts by weight of 2-ethyl-4-methylimidazole were used instead of 7.0 parts by weight of diethylenetriamine and 8.0 parts by weight of 2-ethyl-4-methylimidazole. In the same manner as in the preparation of the curing agent 1, an amine curing agent 4 having a softening point of 120 ° C. and a center particle diameter of 6 μm was obtained. The chemical equivalent of the curing agent 4 to 20 parts by weight of a mixture of 50 parts by weight of the resin A and 50 parts by weight of the resin F was 20 parts by weight.

(Curing agent 5: softening point 100 ° C., central particle size 3 μm, chemical equivalent 25 phr)
1.0 part by weight of resin A, 10.0 parts by weight of diethylenetriamine, and 5.0 parts by weight of 2-ethyl-4-methylimidazole were dissolved in dioxane and reacted. The obtained reaction product was filtered, washed, pulverized by a jet mill, and then classified to obtain an amine-based curing agent 5 having a softening point of 100 ° C. and a central particle diameter of 3 μm. The chemical equivalent of the curing agent 5 to 100 parts by weight of the resin F was 25 parts by weight.

(Curing agent 6: softening point 100 ° C., central particle diameter 6 μm, chemical equivalent 25 phr)
An amine-based curing agent 6 having a softening point of 100 ° C. and a central particle size of 6 μm was obtained in the same manner as in the preparation of the curing agent 5, except that an amine-based curing agent having a center particle size of 6 μm was obtained by classification. The chemical equivalent of the curing agent 6 to 100 parts by weight of the resin F was 25 parts by weight.

(Curing agent 7: softening point 100 ° C., central particle size 5 μm, chemical equivalent 15 phr)
1.0 part by weight of resin A, 10.0 parts by weight of diethylenetriamine, and 2.0 parts by weight of 2-ethyl-4-methylimidazole were dissolved in dioxane and reacted. The obtained reaction product was filtered, washed, pulverized by a jet mill, and then classified to obtain an amine-based curing agent 7 having a softening point of 100 ° C. and a center particle diameter of 5 μm. The chemical equivalent of the curing agent 7 to 100 parts by weight of the resin A was 15 parts by weight.

(Curing agent a: softening point 30 ° C., central particle diameter 6 μm, chemical equivalent 20 phr)
Except that 10.0 parts by weight of diethylenetriamine and 5.0 parts by weight of 2-ethyl-4-methylimidazole were used instead of 20.0 parts by weight of diethylenetriamine and 10.0 parts by weight of 2-ethyl-4-methylimidazole. In the same manner as in the preparation of the curing agent 1, an amine curing agent a having a softening point of 30 ° C. and a central particle diameter of 6 μm was obtained. The chemical equivalent of the curing agent a to 20 parts by weight of the mixture of 50 parts by weight of the resin A and 50 parts by weight of the resin F was 20 parts by weight.

(Curing agent b: softening point 40 ° C., central particle diameter 6 μm, chemical equivalent 20 phr)
Except that 10.0 parts by weight of diethylenetriamine and 5.0 parts by weight of 2-ethyl-4-methylimidazole were used instead of 15.0 parts by weight of diethylenetriamine and 10.0 parts by weight of 2-ethyl-4-methylimidazole. In the same manner as in the preparation of the curing agent 1, an amine curing agent b having a softening point of 40 ° C. and a central particle diameter of 6 μm was obtained. The chemical equivalent of the curing agent b to 20 parts by weight of the mixture of 50 parts by weight of the resin A and 50 parts by weight of the resin F was 20 parts by weight.

(Curing agent c: softening point 50 ° C., central particle diameter 6 μm, chemical equivalent 20 phr)
Except that 10.0 parts by weight of diethylenetriamine and 5.0 parts by weight of 2-ethyl-4-methylimidazole were used instead of 13.0 parts by weight of diethylenetriamine and 8.0 parts by weight of 2-ethyl-4-methylimidazole. In the same manner as in the preparation of the curing agent 1, an amine curing agent c having a softening point of 50 ° C. and a central particle diameter of 6 μm was obtained. The chemical equivalent of the curing agent c to 20 parts by weight of the mixture of 50 parts by weight of the resin A and 50 parts by weight of the resin F was 20 parts by weight.

(Curing agent d: softening point 60 ° C., central particle diameter 6 μm, chemical equivalent 20 phr)
Except that 10.0 parts by weight of diethylenetriamine and 5.0 parts by weight of 2-ethyl-4-methylimidazole were used instead of 12.0 parts by weight of diethylenetriamine and 7.0 parts by weight of 2-ethyl-4-methylimidazole. In the same manner as in the preparation of the curing agent 1, an amine curing agent d having a softening point of 60 ° C. and a central particle diameter of 6 μm was obtained. The chemical equivalent of the curing agent d to 20 parts by weight of the mixture of 50 parts by weight of the resin A and 50 parts by weight of the resin F was 20 parts by weight.

(Curing agent e: softening point 70 ° C., central particle diameter 6 μm, chemical equivalent 20 phr)
Except that 10.0 parts by weight of diethylenetriamine and 5.0 parts by weight of 2-ethyl-4-methylimidazole were used instead of 11.5 parts by weight of diethylenetriamine and 6.0 parts by weight of 2-ethyl-4-methylimidazole. In the same manner as in the preparation of the curing agent 1, an amine-based curing agent e having a softening point of 70 ° C. and a central particle diameter of 6 μm was obtained. The chemical equivalent of the curing agent e to 20 parts by weight of the mixture of 50 parts by weight of the resin A and 50 parts by weight of the resin F was 20 parts by weight.

(Curing agent f: softening point 80 ° C., central particle diameter 6 μm, chemical equivalent 20 phr)
Except that 10.0 parts by weight of diethylenetriamine and 5.0 parts by weight of 2-ethyl-4-methylimidazole were used instead of 11.0 parts by weight of diethylenetriamine and 6.0 parts by weight of 2-ethyl-4-methylimidazole. In the same manner as in the preparation of the curing agent 1, an amine curing agent f having a softening point of 80 ° C. and a center particle diameter of 6 μm was obtained. The chemical equivalent of the curing agent f to 20 parts by weight of the mixture of 50 parts by weight of the resin A and 50 parts by weight of the resin F was 20 parts by weight.

(Curing agent g: softening point 130 ° C., central particle diameter 6 μm, chemical equivalent 20 phr)
Except that 10.0 parts by weight of diethylenetriamine and 5.0 parts by weight of 2-ethyl-4-methylimidazole were used instead of 6.5 parts by weight of diethylenetriamine and 5.0 parts by weight of 2-ethyl-4-methylimidazole. In the same manner as in the preparation of the curing agent 1, an amine curing agent g having a softening point of 130 ° C. and a central particle diameter of 6 μm was obtained. The chemical equivalent of the curing agent g with respect to 100 parts by weight of the mixture of 50 parts by weight of the resin A and 50 parts by weight of the resin F was 20 parts by weight.

(Curing agent h: softening point 140 ° C., central particle diameter 6 μm, chemical equivalent 20 phr)
Except that 10.0 parts by weight of diethylenetriamine and 5.0 parts by weight of 2-ethyl-4-methylimidazole were used instead of 6.0 parts by weight of diethylenetriamine and 5.0 parts by weight of 2-ethyl-4-methylimidazole. In the same manner as in the preparation of the curing agent 1, an amine-based curing agent h having a softening point of 140 ° C. and a central particle diameter of 6 μm was obtained. The chemical equivalent of the curing agent h with respect to 100 parts by weight of the mixture of 50 parts by weight of the resin A and 50 parts by weight of the resin F was 20 parts by weight.

(Curing agent i: softening point 150 ° C., central particle diameter 6 μm, chemical equivalent 20 phr)
Except that 10.0 parts by weight of diethylenetriamine and 5.0 parts by weight of 2-ethyl-4-methylimidazole were used instead of 5.0 parts by weight of diethylenetriamine and 5.0 parts by weight of 2-ethyl-4-methylimidazole. In the same manner as in the preparation of curing agent 1, an amine-based curing agent i having a softening point of 150 ° C. and a central particle diameter of 6 μm was obtained. The chemical equivalent of the curing agent i to 20 parts by weight of the mixture of 50 parts by weight of the resin A and 50 parts by weight of the resin F was 20 parts by weight.

(Curing agent j: softening point 100 ° C., central particle size 10 μm, chemical equivalent 25 phr)
An amine-based curing agent j having a softening point of 100 ° C. and a center particle size of 10 μm was obtained in the same manner as in the preparation of the curing agent 5, except that an amine-based curing agent having a center particle size of 10 μm was obtained by classification. The chemical equivalent of the curing agent j to 100 parts by weight of the resin F was 25 parts by weight.

(Curing agent k: softening point 100 ° C., central particle size 15 μm, chemical equivalent 25 phr)
An amine-based curing agent k having a softening point of 100 ° C. and a center particle size of 15 μm was obtained in the same manner as in the preparation of the curing agent 5, except that an amine-based curing agent having a center particle size of 15 μm was obtained by classification. The chemical equivalent of the curing agent k with respect to 100 parts by weight of the resin F was 25 parts by weight.

<Ultra-fine particle silica>
AEROSIL 200, manufactured by Nippon Aerosil Co., Ltd., average primary particle size: about 12 nm
<Example 1>
50 parts by weight of resin A and 50 parts by weight of resin F as a main agent, 40 parts by weight of curing agent 1 as a curing agent, and 1.0 part by weight of ultrafine silica were mixed with a planetary stirring mixer (manufactured by Shinky Corporation). Adhesive 1 was prepared by mixing for 10 minutes using AR-250.

Next, the foot (190 μm diameter) of a plant (rhodium surface) was inserted into the hole (220 μm diameter) of the base (brass, thickness: 400 μm) from the front side of the base. The adhesive 1 was injected from the back side of the base using a dispenser. Thereafter, the substrate was heated at 120 ° C. for 10 minutes to cure the adhesive, and the plant was adhered to the surface of the substrate to produce a timepiece dial.

観 察 The watch dial was observed from the front side to check whether the adhesive had protruded from the plant. Also, using a push-pull gauge (manufactured by Aiko Engineering Co., Ltd., model number: 9500), the foot of the plant was pressed from the back side of the timepiece dial, and the load when the plant was detached from the base was measured. The adhesion between the substrate and the substrate was evaluated. Further, the timepiece dial was dropped freely from a height of 1 m, and the presence or absence of detachment of the plant from the base was confirmed.

(4) The adhesive 1 was stored at 35 ° C. for 3 days, and the storage stability was evaluated.

Further, an adhesive 1 is applied to the surface of a white dial for a watch (a white dial for the citizen, manufactured by Citizen Watch Co., Ltd.), and the white dial for a watch is placed in a watch case (the citizen, manufactured by Citizen Watch Co., Ltd., The Citizen). Case). This watch case was placed in a sunshine weather tester (manufactured by Suga Test Instruments Co., Ltd., model number: WEL-SON-DCB), and a 100-hour sunshine weather test (temperature: about 63 ° C., light intensity: 300 W / m ² ) was performed. . The color difference (ΔLab) of the white dial for a watch before and after this test was measured using an ultraviolet-visible spectrophotometer (V-570, manufactured by JASCO Corporation) equipped with an integrating sphere.

The results are shown in Table 1.

<Examples 2 to 4>
Adhesives 2 to 4 were prepared in the same manner as in Example 1, except that 40 parts by weight of each of the curing agents 2 to 4 shown in Table 1 were used instead of the curing agent 1. Were evaluated for physical properties. Table 1 shows the results.

<Comparative Examples 1 to 9>
Except that 40 parts by weight of each of the curing agents a to i shown in Table 2 were used instead of the curing agent 1, adhesives a to i were prepared in the same manner as in Example 1, and these adhesives a to i were prepared. Were evaluated for physical properties. Table 2 shows the results.

<Example 5>
Except for using 100 parts by weight of resin F instead of 50 parts by weight of resin A and 50 parts by weight of resin F as the main agent, and using 50 parts by weight of curing agent 5 instead of curing agent 1 as the curing agent An adhesive 5 was prepared in the same manner as in Example 1.

Next, except that the adhesive 5 was used in place of the adhesive 1 and the temperature at which the adhesive was cured was changed from 120 ° C. to 110 ° C., the plant was placed on the surface of the substrate in the same manner as in Example 1. A watch dial was prepared by bonding, and the physical properties of the adhesive 5 were evaluated.

(5) The adhesive 5 was stored at 35 ° C. for 3 days, and the storage stability was evaluated.

The results are shown in Table 3.

<Example 6>
An adhesive 6 was prepared in the same manner as in Example 5 except that 50 parts by weight of the curing agent 6 shown in Table 3 was used instead of the curing agent 5, and the physical properties of the adhesive 6 were evaluated. Table 3 shows the results.

<Comparative Examples 10 to 11>
In the same manner as in Example 5 except that 50 parts by weight of each of the curing agents j to k shown in Table 3 were used instead of the curing agent 5, adhesives j to k were prepared. Were evaluated for physical properties. Table 3 shows the results.

<Example 7>
100 parts by weight of resin A was used instead of 50 parts by weight of resin A and 50 parts by weight of resin F, and 22.5 parts by weight of curing agent 7 was used instead of curing agent 1 as a curing agent. Except for the above, an adhesive 7 was prepared in the same manner as in Example 1.

Next, the plant was placed on the surface of the substrate in the same manner as in Example 1 except that the adhesive 7 was used instead of the adhesive 1, and the temperature at which the adhesive was cured was changed from 120 ° C to 100 ° C. A timepiece dial was produced by bonding, and the physical properties of the adhesive 7 were evaluated.

(5) The adhesive 7 was stored at 35 ° C. for 3 days, and the storage stability was evaluated.

These results are shown in Table 4.

<Examples 8 to 9>
Adhesives 8 to 9 were prepared in the same manner as in Example 7 except that the amount of the curing agent 7 shown in Table 4 was used instead of 22.5 parts by weight of the curing agent 7. -9 were evaluated. Table 4 shows the results.

<Comparative Examples 12 to 13>
The adhesives m to n were prepared in the same manner as in Example 7 except that the amount of the curing agent 7 shown in Table 4 was used instead of 22.5 parts by weight of the curing agent 7. To n were evaluated. Table 4 shows the results.

<Example 10>
Adhesive 10 was prepared in the same manner as in Example 2 except that 100 parts by weight of resin A was used instead of 50 parts by weight of resin A and 50 parts by weight of resin F as the main agent.

Next, the plant was placed on the surface of the base in the same manner as in Example 2 except that the adhesive 10 was used in place of the adhesive 2, and the temperature at which the adhesive was cured was changed from 120 ° C to 100 ° C. A timepiece dial was produced by bonding, and the physical properties of the adhesive 10 were evaluated.

(4) The adhesive 10 was stored at 35 ° C. for 3 days, and the storage stability was evaluated.

These results are shown in Table 5.

<Examples 11 to 15>
Adhesives 11 to 15 were prepared in the same manner as in Example 10 except that the amount of ultrafine silica shown in Table 5 was used instead of 1.0 part by weight of ultrafine silica. １５15 were evaluated. Table 5 shows the results.

<Comparative Examples 14 to 15>
Adhesives p to q were prepared in the same manner as in Example 10 except that the amount of the ultrafine silica particles shown in Table 5 was used instead of 1.0 parts by weight of the ultrafine silica particles. To q were evaluated. Table 5 shows the results.

<Example 16>
250 parts by weight of resin A as a main agent, 100 parts by weight of curing agent 2 as a curing agent, 2.0 parts by weight
Parts by weight of ultrafine silica and 0.5 parts by weight of 2,2-oxybis (5,5-dimethyl-1,3,2-dioxaborinane) were mixed with a planetary stirring mixer (Fritsch, model number: P) -4) was mixed for 10 minutes to prepare an adhesive 16. The adhesive 16 was stored at 35 ° C. for 3 days and at 30 ° C. for 10 days, and the preservability was evaluated.

Next, the plant was placed on the surface of the base in the same manner as in Example 1 except that the adhesive 16 was used in place of the adhesive 1, and the temperature at which the adhesive was cured was changed from 120 ° C to 100 ° C. A timepiece dial was produced by bonding, and the physical properties of the adhesive 16 were evaluated.

In addition, for a timepiece dial produced using the adhesive composition stored at 30 ° C. for 10 days, a moisture resistance test (preserved at a temperature of 40 ° C. and a humidity of 95% for 1000 hours) and a heat degradation test (at 80 ° C.) 1000 hours) and a 300-hour sunshine weather test (temperature: about 63 ° C., light intensity: 300 W / m ² ) using a sunshine weather tester (manufactured by Suga Test Instruments, model number: WEL-SON-DCB). Carried out. After performing each test, the adhesion between the substrate and the plant and the presence or absence of detachment of the plant by a drop test (1 m height) were confirmed.

The results are shown in Table 6.

<Examples 17 to 19>
Instead of 0.5 parts by weight of 2,2-oxybis (5,5-dimethyl-1,3,2-dioxaborinane), the amount of 2,2-oxybis (5,5-dimethyl-1,5 Except for using 3,2-dioxaborinane), adhesives 17 to 19 were prepared in the same manner as in Example 16, and the physical properties of these adhesives 17 to 19 were evaluated. Table 6 shows the results.

<Comparative Example 16>
Instead of 0.5 parts by weight of 2,2-oxybis (5,5-dimethyl-1,3,2-dioxaborinane), 2.5 parts by weight of 2,2-oxybis (5,5-dimethyl-1,5 An adhesive r was prepared in the same manner as in Example 16 except that 3,2-dioxaborinane) was used, and the physical properties of the adhesive r were evaluated. Table 6 shows the results.

<Comparative Example 17>
A timepiece dial was prepared in the same manner as in Example 1 except that a rubber-based adhesive (a die bond (model number: # 1600) manufactured by Nogawa Chemical Co., Ltd.) was used instead of the adhesive 1 as an adhesive. Was evaluated. As a result, the adhesive strength was 0.6 kgf.

Further, the timepiece dial was subjected to a moisture resistance test, a heat deterioration test, and a sunshine weather test in the same manner as in Example 17, and then subjected to an adhesion test and a drop test (height: 1 m). The presence or absence was checked. As a result, the adhesive strength after the test was reduced by 20 to 50% as compared with before each test.

<Reference Example 1>
After inserting the foot of the plant into the hole of the base, caulking and fixing the plant to the base, except that the adhesive was injected from the back side of the base, each of the timepiece dials was performed in the same manner as in Examples 1 to 19. Produced. As a result, the clock face without the caulking and the watch face with the caulking showed the same characteristics.

接着 The adhesive composition for precision parts according to the present invention can be used for firmly bonding precision parts, which have conventionally required caulking, without caulking. In addition, the timepiece dial according to the present invention does not detach the plant even after long-term use, and there is little need to repair the timepiece.

FIG. 1 is a top view of a timepiece dial according to the present invention. FIG. 2 is a top view of the dial base used in the present invention. FIG. 3 is a sectional view of the timepiece dial shown in FIG.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Watch dial 2 Plant 11 Base 11a Hole for inserting plant foot 11b Adhesion site 21 Plant for hour character 21a Plant foot 22 Plant for window frame 23 Plant for logo mark

Claims (6)

(A) a main agent comprising a bisphenol A type epoxy resin and / or a bisphenol F type epoxy resin;
(B) an amine-based curing agent which is solid at ordinary temperature and has a softening point of 90 to 120 ° C. and an average particle size of 6 μm or less;
(C) an adhesive composition for precision parts containing ultrafine silica particles,
The amine-based curing agent (B) is contained in an amount of 1.5 to 2.5 times the chemical equivalent to the main agent (A),
An adhesive composition for precision parts, wherein ultrafine silica (C) is contained in an amount of 0.5 to 2.0 parts by weight based on 100 parts by weight of the base material (A). The adhesive composition for precision parts according to claim 1, wherein the amine-based curing agent (B) is a reaction product of a bisphenol A type epoxy resin and / or a bisphenol F type epoxy resin with a polyamine. . 3. The adhesive composition for precision parts according to claim 1, further comprising $ 2,2-oxybis (5,5-dimethyl-1,3,2-dioxaborinane). 4. The composition according to claim 3, wherein 1,2 parts by weight of 2,2-oxybis (5,5-dimethyl-1,3,2-dioxaborinane) is contained with respect to 100 parts by weight of the amine-based curing agent (B). 3. The adhesive composition for precision parts according to 1.). A timepiece dial, wherein a plant is adhered to a dial base using the adhesive composition for precision parts according to any one of claims 1 to 4. (I) inserting the foot of the plant into the hole of the dial base of the watch from the front side of the base;
(II) a step of injecting the adhesive composition for precision parts according to any one of claims 1 to 4 from a back side of the base into a hole of the base into which the foot of the plant is inserted;
(III) a step of heating the substrate obtained in the step (II) to cure the adhesive, thereby fixing the plant to the surface of the substrate.

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