JP2001247608A - Protective agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protective agent having a long shelf life without using a UV furnace, curable under a small UV irradiator and not causing coil discoloration. SOLUTION: The UV-curing protective agent covers the external circumference of the coil, and comprises an acrylate having not more than three functional groups, a polymerization initiator not sensitive to visible radiation, and a fluorescent substance. A thixo agent is added to the same protective agent for the coverage of the end sections of the coil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective agent, and more particularly, to a protective agent which is effective for use in a protective portion of a coil used for small parts.

[0002]

2. Description of the Related Art In recent years, electronic equipment has been rapidly reduced in size.
Small portable terminals were developed. In the field of electronic timepieces included in small electronic devices, miniaturization is progressing in consideration of design, weight, size, and the like.

The basic structure of an electronic timepiece is composed of an electronic circuit including a battery, a wheel train for moving hands for displaying time, and a motor for converting electric power to motive power. For the motor part, a coil formed by winding a wire around a core made of a soft magnetic material is used as a component. BACKGROUND ART An electronic timepiece that generates electric power has a coil for converting mechanical energy into electric energy.

The structure of such a conventional coil will be described with reference to the sectional view of the coil shown in FIG. The coil 100 has a structure in which a conductive thin conductive material 109 such as copper is wound around a core 105 made of a soft magnetic material.
For this reason, the winding cores 10 at both ends of the wound conductive wire 109 are prevented so that the conductive wire 109 does not collapse due to a physical impact.
5 is fitted with a winding frame 103. As the winding frame 103, a material formed by punching a polymer material such as polyester or polypropylene into a desired shape and performing a barrel treatment to remove burrs remaining on the cut surface can be used.

[0005] The two terminals 109a of the conductive wire 109 are connected to a wiring pattern 107a on a terminal sheet 107 for establishing conduction with other components. Also, the coil 10
When the 0 is incorporated in the watch or when the coil is removed from the watch for repair, the exposed conductor 10
In order to prevent the disconnection of the wire 9, the outer periphery and the terminal portion of the wound conductive wire 109 are covered with a protective layer 101. The protective layer 101 is configured to be in contact with the side surface 103a of the winding frame in consideration that the size of the entire coil 100 is not too large. The protective layer 101 is formed by applying a protective agent (ultraviolet curable adhesive) to a necessary portion on the coil and then irradiating with ultraviolet rays to cure the coil.

Heretofore, the present applicant has used as a protective agent, for example, an ultraviolet-curable adhesive AS-1000Y, A
S-1000G has been used. The material is mainly made of acrylic and contains additives such as a yellow colorant (transcribed from the catalog of Asec, MSDS).

[0007]

When a coil is produced using a conventional protective agent, the speed of curing is so low that 4 k
Since a large-sized UV furnace having a W rating had to be used, power consumption during production increased, and a large space was required despite the production of small parts. Furthermore, since the carrier for production passes through the UV furnace, there is a problem that the life of the plastic carrier is shortened due to deterioration. In addition, there is a problem in that a disconnection occurs at the time of curing, or the applied protective agent flows into the conductive wire material, so that the protective layer after curing becomes thin and does not function as a protective layer. For this reason, an inspection process is installed in the coil production line.

Further, a yellow colorant is added to the conventional protective agent for inspection. In the inspection process, the amount of colorant is set to the minimum amount to inspect whether the protective agent is applied well, but if you make a coil using this, the appearance color will change color There is a problem that went. In watch parts, the appearance is particularly important, so that discoloration is a major issue.

Further, the conventional protective agent used for the terminal portion has a problem that the resin is separated into a liquid portion and a portion on the gel with time. In addition, it is necessary to always store the material in a refrigerator in order to prevent the progress of the separation, and there is a problem that the stored material cannot be used at the time of a power failure. In addition, since the interior of the production line is generally manufactured under a fluorescent lamp, the conventional protective agent hardens even with the fluorescent lamp, so the interior light hits the protective agent supply unit when performing maintenance. The workability was poor due to the curing of the resin in the supply section. As described above, there is a problem regarding the storability.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and curing can be performed by a UV irradiator having a small work space and a low power consumption without using a UV furnace. An object of the present invention is to provide a protective agent which is possible and does not deteriorate the appearance quality due to discoloration of the coil and has good storage stability.

[0011]

The gist of the present invention to achieve the above object is as follows. It is characterized in that acrylate is used as a monomer of a protective agent, and at least 0.01 to 8 wt% of a photopolymerization initiator is mixed with the acrylate, and the acrylate has three or less acrylic groups in one molecule. In particular, as a protective agent for the outer peripheral portion, the viscosity when at least 0.01 to 8 wt% of a photopolymerization initiator is mixed with acrylate is 800 mPa · s to 1500 mPa · s at a temperature in the range of 20 ° C. to 45 ° C.
And a monomer viscosity of 500 mPa · s or less at a temperature in the range of 20 ° C. to 45 ° C.

As a protective agent for the terminal part, a thixotropic agent of 0.1
And 20 wt% of the thixo agent is silicon dioxide. Further, it is characterized by adding 0.01 to 5 wt% of a fluorescent agent, characterized in that the photopolymerization initiator has no sensitivity to visible light, and that the photopolymerization initiator contains at least an acetophenone derivative, α -Characterized by containing a compound selected from aminoacetophenone derivatives, and being used as a protective agent for coils of electronic equipment.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the compounds shown below.

The present applicant also manufactures a timepiece and a coil as a component thereof. The coil production line performs production at a rate of one per second per line. The protective agent for forming the protective layer on the outer peripheral portion is applied using a brush or the like. In order to complete the coating process in one second, the time required for the substantial coating is about 0.5 seconds, so it is necessary to adjust the coating conditions. For this reason, 2
It has a temperature controller that can be adjusted from 5 ° C to 45 ° C. The viscosity that can be applied under this temperature condition is 800 mPa
S to 1500 mPa · s. If the viscosity is too low, the resin will flow and result in a failure, while if the viscosity is too high, the resin will be biased, resulting in failure. The coil in which the resin has flowed is not protected because the protective layer is thinned, and the coil in which the offset has occurred is partially thickened so that it cannot be stored in the timepiece.

On the other hand, the protective agent for forming the protective layer of the terminal portion is applied with a small device called a dispenser capable of discharging a fixed amount of resin, such as a syringe.
In order to complete the coating process in one second, the time required for the substantial coating is about 0.5 seconds, so it is necessary to adjust the coating conditions. For this purpose, the production machine is equipped with a temperature controller capable of adjusting the temperature from 25 ° C. to 45 ° C. In order to perform good ejection, a soft material has good ejection properties, so that the viscosity of the monomer is from 20 ° C. to 45 ° C. within a temperature controllable range.
Was 500 mPa · s or less.

The protective agent at the terminal portion is applied to the wiring pattern on the terminal sheet at the contact point between the two terminals made of a conductive material. Therefore, when the protective agent flows, it covers the wiring pattern.
There is a problem that conduction with other components cannot be obtained. As a thixotropic agent, 2
Thixotropy was imparted by adding silicon oxide. The appropriate amount of addition was 0.1 wt% to 20 wt%. If the addition amount was too small, the resin would flow, while if it was too large, the resin would be hard and could not be applied well.

Examples of the monomer include an acrylate having an acryl group and a methacrylate having a methacryl group, and a monomer having a plurality of each group in one molecule. In order to accelerate the curing reaction, it is advantageous to have many acrylic or methacrylic groups in one molecule.
Has a diameter of 25 μm or less, and considering that curing shrinkage must be controlled, the number of acryl groups and methacryl groups in one molecule is preferably within three.

When the reactivity of the acryl group and the methacryl group was compared, the reactivity of the acryl group was higher than that of the methacryl group, and only monomers having the acryl group could be used in a mass production machine.

As a small-sized ultraviolet irradiator that can be used in a production line, a small-sized ultraviolet irradiator having a size of 500 W or less is preferable because of its small size.
It is more preferable that the power required for the production be small. The applicant has selected a UV irradiator capable of irradiating with a small fiber of 250 W. In order to cure in a short time (with the coil manufacturing line owned by the applicant, the UV irradiation time is within 0.7 seconds at the maximum) with a low-power UV irradiator used after the improvement, it is necessary to start photopolymerization. It is preferable to widen the wavelength range of sensitivity at which the agent functions, but since the production line is manufactured under fluorescent lamp illumination, it is easier to work without curing with the light of fluorescent lamps, which is advantageous in manufacturing. is there. Therefore 4
It is important to select a polymerization initiator that does not absorb light in the visible light range of 00 nm or more. The photopolymerization initiator used in this example used an acetophenone derivative and an α-aminoacetophenone derivative while also paying attention to the absorption wavelength, but other initiators can be used if the intended conditions are satisfied. .

[0020] The amount of the photopolymerization initiator is preferably in the range of 0.01 wt% to 8 wt%. If the amount is too small, it will be uncured, and if it is too large, the bottom will be uncured and will be defective.

Whether or not the protective layer is formed in a desired state is determined by using an image processing apparatus or the like. In image processing equipment, especially unpainted, paint position is too wide,
We judge whether it is shifted. The applicant does not want to color the resin with a special color for image processing. For this reason, phosphors (organic dyes and pigments such as inorganic substances and coumarin derivatives) that emit light when irradiated with black light are used in 0.0
It was added in the range of 1 wt% to 5 wt%. If the added amount is small, the light emission is small, so that a problem that the image processing apparatus does not recognize it occurs. On the other hand, if the added amount is too large, the curing reaction of the resin is suppressed and the resin becomes an uncured resin, resulting in failure.

(Example) The optimum amount of the photopolymerization initiator is determined. Core 105 with winding frame 103 and terminal sheet 107
Around the conductive wire 109 having a thickness of 25 μm or less,
09, a semi-finished product of the coil 100 in which the terminal 109a was connected to the wiring pattern 107a on the terminal sheet 107 was prepared. An acetophenone derivative as a photopolymerization initiator and α are added to the acrylate having a viscosity of 800 mPa · s to 1500 mPa · s at any temperature of 20 ° C. to 45 ° C.
The aminoacetophenone derivative in 0.005, 0.0
A protective agent to which 1, 5, 8, and 10 wt% was added was applied using a brush. At the temperature of any one of 20 ° C to 45 ° C at the terminal, a photopolymerization initiator is added to an acrylate having a viscosity of 500 mPa · s or less, and a fine powder of silicon dioxide as a thixotropic agent is 0.1 to 20 wt%. After applying the added protective agent using a dispenser, UV irradiation was performed to produce a coil.

As a result, the amount of the photoinitiator was 0.01 wt%.
In any case, the protective agent was cured well in any case, and the coil could be manufactured. However, when the photoinitiator concentration was 0.005 wt% and when the photoinitiator concentration was 10 wt%, Uncuring occurred and a good coil could not be obtained. From the above results, it was found that the appropriate amount of the photoinitiator to be added to the protective agent was 0.01 wt% to 8 wt%. Table 1 summarizes the above results.

[0024]

[Table 1]

The number of acrylic groups in one molecule of the acrylic monomer will be examined. A semi-finished product of the coil 100 in which a conducting wire 109 having a thickness of 25 μm or less is wound around a winding core 105 provided with a winding frame 103 and a terminal sheet 107, and a terminal 109 a of the conducting wire 109 is connected to a wiring pattern 107 a on the terminal sheet 107. Was prepared. The number of acrylic groups in one molecule is 2, 3
And four at a temperature in the range of 20 ° C. to 45 ° C. and a viscosity of 8
A protective agent for the outer peripheral portion was prepared using an acrylic monomer having a viscosity of from 00 mPa · s to 1500 mPa · s and a photopolymerization initiator. The outer periphery of the coil was coated with a brush using this protective agent, and UV irradiation was performed to form a coil.

As a result, when the number of acryl groups in one molecule was 3 or less, a good coil could be produced without disconnection due to little curing shrinkage in any case, but a good coil was produced. When the number was 4, the curing shrinkage was large, so that disconnection occurred. From the above, the protective agent for protecting the outer peripheral portion has three acrylic groups in one molecule.
It has been found that not more than acrylic monomers are suitable.
The results are summarized in Table 2.

[0027]

[Table 2]

A conductor wire 109 having a thickness of 25 μm or less is wound around a winding core 105 having a winding frame 103 and a terminal sheet 107 attached thereto.
A semi-finished product of the coil 100 in which the terminal 109a of the conductor 109 was connected to the wiring pattern 107a on the terminal sheet 107 was prepared. The number of acrylic groups in one molecule is 2, 3
Four at a temperature in the range of 20 ° C. to 45 ° C. and a viscosity of 5
A terminal part protective agent was prepared using an acrylic monomer having a viscosity of 00 mPa · s or less, a photopolymerization initiator, and a thixotropic agent. The protective agent was applied to the terminal of the coil using a dispenser, and UV irradiation was performed to form a coil.

As a result, when the number of acryl groups in one molecule was 3 or less, a good coil could be produced without disconnection in any case, but the number of acryl groups in one molecule was 4 In some cases, a break occurred. From the above, the protective agent for protecting the outer peripheral portion has three acrylic groups in one molecule.
It has been found that not more than acrylic monomers are suitable.
The results are summarized in Table 3.

[0030]

[Table 3]

The following experiment was conducted for the purpose of finding a suitable viscosity for the protective agent on the outer peripheral portion. A semi-finished product of the coil 100 in which a conducting wire 109 having a thickness of 25 μm or less is wound around a winding core 105 provided with a winding frame 103 and a terminal sheet 107, and a terminal 109 a of the conducting wire 109 is connected to a wiring pattern 107 a on the terminal sheet 107. Was prepared. Subsequently, at the temperature in the range of 20 ° C. to 45 ° C., the viscosity is 500 mPa.
・ S, 800 mPa ・ s, 1000 mPa ・ s, 130
0mPa · s, 1500mPa · s, 1800mPa ·
After applying a protective agent comprising the acrylate of s and a photopolymerization initiator using a brush, UV irradiation was performed to confirm the state of formation of the protective layer.

As a result, 1000 mPa · s, 1300
In any case, the coil formed using the protective agent of mPa · s and 1500 mPa · s formed a good protective layer, but when the protective agent of 500 mPa · s was used, the protective agent would flow too much, The thickness of the protective layer was so thin that it could not function as a protective layer, resulting in a defective product. 180
When a protective agent having a pressure of 0 mPa · s was used, the resin did not flow, resulting in uneven coating and a failure. From the above, the viscosity of the protective agent at the outer peripheral portion is 800 mPa · s to 1500 m at a temperature in the range of 20 ° C. to 45 ° C.
It turned out that it must be Pa · s. Table 4 shows the results
Put together.

[0033]

[Table 4]

The viscosity range of the monomer of the protective agent in the terminal portion;
The following experiment was conducted in order to find the range of the addition amount of the thixotropic agent. Core 1 with winding frame 103 and terminal sheet 107
A semi-finished product of the coil 100 was prepared in which a conductive wire 109 having a thickness of 25 μm or less was wound around 05 and the terminal 109 a of the conductive wire 109 was connected to the wiring pattern 107 a on the terminal sheet 107. Subsequently, the viscosity was 300 mPa · s, 500 mPa · s, 8 at a temperature in the range of 20 ° C. to 45 ° C.
Using a dispenser, a protective agent obtained by adding 0, 0.1, 10, 20, and 25 wt% of silicon dioxide fine powder as a thixotropic agent to a acrylate obtained by adding a photopolymerization initiator to an acrylate of 00 mPa · s. Thereafter, UV irradiation was performed to produce a coil.

As a result, the monomer viscosity was 300 mPa ·
When the addition amount of silicon dioxide was 0.1, 10, and 20 wt%, the coil could be produced satisfactorily using 500 mPa · s and the monomer viscosity was 800 mPa · s. The amount of silicon dioxide added is 2
When the content is less than 0 wt%, the resin is thread-like tailed when the protective agent is discharged by the dispenser, so that the protective agent adheres to unnecessary portions and becomes defective. When the added amount of silicon dioxide was 25 wt%, the protective agent was hardened in any case, and the protective agent could not be stably discharged from the dispenser. In the case where silicon dioxide was not added, the protective agent flowed to an unnecessary portion in any case, resulting in a failure. From the above results, the protective agent for protecting the terminal portion has a viscosity of 50 ° C. at a temperature in the range of 20 ° C. to 45 ° C.
At 0 mPa · s or less, it was found that it is better to contain 0.1 to 20 wt% of silicon dioxide as a thixotropic agent. Table 5 summarizes the above results.

[0036]

[Table 5]

An experiment was performed to determine the amount of phosphor added.
A conductive wire 109 having a thickness of 25 μm or less is wound around a winding core 105 on which a winding frame 103 and a terminal sheet 107 are attached.
Terminal 109a is connected to wiring pattern 1 on terminal sheet 107.
A semi-finished product of the coil 100 connected to 07a was prepared.
The number of acrylic groups in one molecule is less than 3
At a temperature of 800 ° C.
500 mPa · s acrylic monomer, a photopolymerization initiator and a coumarin derivative as a fluorescent substance are 0, 0.01, 1,
5.8 wt% was added to prepare a protective agent for the outer peripheral portion. At a temperature in the range of 20 ° C. to 45 ° C. where the number of acrylic groups in one molecule is 3 or less, an acrylic monomer having a viscosity of 500 mPa · s or less, a photopolymerization initiator, a thixotropic agent, and a coumarin derivative as a fluorescent substance. , 0.01, 1, 5 and 8 wt% were added to prepare a protective agent for the terminal portion. This protective agent was applied to the outer peripheral portion and the terminal portion of the coil, UV irradiation was performed, a coil was prepared, and an inspection was performed by an image processing device under black light.

As a result, the amount of the phosphor added was 0.01 wt%.
The coil using the protective agent of 5% by weight was well recognized by the image processing apparatus, and the application state could all be inspected in the production line. In the case of 0 wt%, the presence or absence of the resin was not confirmed, and the inspection could not be performed. In the case of 8 wt%, although the inspection could be performed, the resin was not cured and became a defective product. From the above results, it was found that the amount of the phosphor added was in the range of 0.01 wt% to 5 wt%. Table 6 summarizes the above results.

[0039]

[Table 6]

The terminal portion has a viscosity of 500 at a temperature in the range of 20 ° C. to 45 ° C. where the number of acryl groups in one molecule is 3 or less.
Using an acrylic monomer of mPa · s or less, a protective agent composed of a photopolymerization initiator, a thixo agent, and a fluorescent substance,
20 ° C to 45 ° C with 3 or less acrylic groups in the molecule
At a temperature ranging from 800 mPa · s to 1500
A coil was formed using an acrylic monomer of mPa · s and a protective agent composed of a photopolymerization initiator and a phosphor. Using this coil, a watch movement made by Citizen Watch (N
o. 2035) was assembled. As a result, the watch operated well without any delay between -10 ° C and 80 ° C. In addition, when the appearance quality of the coil was observed, the discoloration disappeared and the added value was increased.

In addition, during the production, work was performed under a fluorescent lamp, but the resin did not solidify, so that no defective product was produced. Further, the work efficiency was improved, and the time required for maintenance was shortened, so that the production efficiency was improved. Since the resin did not separate at room temperature during the test period, the resin charged in the apparatus did not separate, so that maintenance was unnecessary. Further, since the stored resin does not separate at room temperature, the resin stored at room temperature can be used immediately. (Conventionally, it was refrigerated, and it was necessary to return it to room temperature one hour before starting use.)

[0042]

As described above, according to the present invention, the viscosity is 1 at 800 mPa · s or more at any temperature of 20 ° C. to 45 ° C.
An acrylate having three or less acrylic groups in one molecule is used for a monomer having a molecular weight of 500 mPa · s or less, and an acetophenone derivative or α
-0.01 to 8 wt% of aminoacetophenone derivative
And a phosphor such as a coumarin derivative in an amount of 0.01 to 5 wt.
% Of a protective agent is used on the outer periphery, and an acrylate having not more than 3 acrylic groups per molecule in a monomer having a viscosity of 500 mPa · s or less at any temperature of 20 ° C. to 45 ° C. is used. 0.1 to 20 wt% of silicon dioxide is added as a thixo agent, 0.01 to 8 wt% of an acetophenone derivative or an α-aminoacetophenone derivative as a photopolymerization initiator, and 0.01 to 8 wt% of a coumarin derivative or the like. Since the protective agent to which 5 wt% was added was used for the outer peripheral portion, a good coil component could be obtained without discoloring the color of the coil.

As a result, a watch with a beautiful appearance was completed, and the added value of the product was increased. Further, in the manufacturing process, the workability was improved because the curing was not performed by the light of the fluorescent lamp, and the curing at the tip of the coating apparatus was eliminated, so that defective products were not created and the yield was improved. In addition, curing has been performed using a large-sized UV furnace, but by using the protective agent of the present invention, production can be performed with a small 250 W UV irradiator, so that a manufacturing space can be reduced. The power consumption involved in production was reduced. In addition, since the protective agent of the present invention is of a type that emits light with black light, the image detector can easily determine.

As a result, the defect can be accurately determined. In addition, since the separation of the protective agent due to the preservability has been eliminated, a refrigerator is not required for storage. For this reason, no material is wasted when a power failure occurs. In addition, since the carrier does not pass through the UV furnace during manufacturing, the life of the carrier has been greatly extended, and therefore, there is no need to prepare a spare carrier.

[Brief description of the drawings]

FIG. 1 is a sectional view of a coil.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 coil 101 protective layer 103 reel 103 a side surface of reel 105 core 107 terminal sheet 107 a wiring pattern 109 conductor 109 a terminal

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J011 PA02 PA13 PB38 PB40 PC02 QA03 QA11 QA21 SA01 SA15 UA01 VA01 WA02 4J038 FA111 HA446 JA33 KA04 MA15 PB09 5E070 AA01 AB10 DA15

Claims (10)

[Claims] 1. A protective agent characterized in that acrylate is used as a monomer, and at least 0.01 to 8 wt% of a photopolymerization initiator is mixed with the acrylate. 2. The protective agent according to claim 1, wherein the monomer comprises an acrylate having three or less acrylic groups in one molecule. 3. An acrylate is used as a monomer, and at least 0.01 to 8% by weight of a photopolymerization initiator is mixed with the acrylate to have a viscosity of 8 to 20 ° C. to 45 ° C.
The protective agent according to claim 1 or 2, wherein the protective agent is in a range from 00 mPa · s to 1500 mPa · s. 4. The protective agent according to claim 2, wherein the viscosity of the monomer is 500 mPa · s or less at a temperature in the range of 20 ° C. to 45 ° C. 5. The protective agent according to claim 4, wherein a thixotropic agent is added in an amount of 0.1 to 20% by weight. 6. The protective agent according to claim 5, wherein the thixotropic agent is silicon dioxide. 7. The protective agent according to claim 1, wherein a fluorescent agent is added in an amount of 0.01 to 5 wt%. 8. The protective agent according to claim 1, wherein the photopolymerization initiator has low sensitivity to visible light. 9. The protective agent according to claim 1, wherein the photopolymerization initiator contains at least a compound selected from an acetophenone derivative and an α-aminoacetophenone derivative. 10. The protective agent according to claim 1, wherein the protective agent is used as a protective agent for a coil of an electronic device.