JPS59136371A - Bonding of photosensitive resin - Google Patents

Abstract

PURPOSE:To raise production efficiency and to obtain commodities having chemically stable bonded layer and high reliability, by curing a photosensitive resin adhesive between bond parts of plural parts isolated from oxygen in air, so that they are bonded. CONSTITUTION:For example, a dried nitrogen gas is introduced from the nozzle 3 equipped with the cover 50 of a continuous ultraviolet irradiation device into the interior of the cover 50, so that it is isolated from oxygen in air. The member 41 to be bonded before curing and adhesion is continuously transported to the ultraviolet irradiation part 13 divided by the cover 50 by operation of the conveyor belt 60, so that the member 41 to be bonded can be irradiated with ultraviolet rays in a state of complete isolation from oxygen, and bonded at raised curing reaction rate. A method to isolate oxygen is preferably to blow an inert gas such as nitrogen gas, etc. on the bond parts.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photosensitive resin bonding method for curing and bonding at least two parts while blocking oxygen around them.

FIG. 1 is a longitudinal sectional view showing an embodiment of a conventional continuous ultraviolet irradiation device. Ultraviolet light 2 is evenly irradiated from the ultraviolet lamp 1 toward the upper surface 61 of the conveyor belt 60. The conveyor belt 60 operates at a constant speed, and on the upper surface 61 of the conveyor belt 60, the members 41 to be bonded, which have not been supplied from the supply chute 8 and have not yet been cured and bonded, are lined up one after another. As it moves, it moves from the inlet 30 to the outlet 31, and during that time, it continuously passes through the ultraviolet irradiation section 16, and the member 41 to be bonded before being cured and bonded changes to the member 42 to be bonded after being cured and bonded. ejected from the door.

That is, the place where the adhesive part is cured is the ultraviolet ray irradiation section 16, and the atmosphere of the irradiation section 16 is the atmosphere even within the cover 50, so that there is a sufficient amount of oxygen. Photosensitive resin adhesives have a bonding effect through a photosensitive curing reaction caused by ultraviolet irradiation.

If oxygen is present in the atmosphere during ultraviolet irradiation, the initiation of the curing reaction will be inhibited and the time required for one reaction will become longer.

This is one of the biggest drawbacks of photosensitive resin adhesives.

One way to compensate for this drawback has been to extend the ultraviolet irradiation time.

That is, in this conventional example, it was necessary to reduce the speed of the conveyor belt 60 or to repeat the irradiation. As a result, production efficiency has been reduced.

Moreover, if the ultraviolet ray irradiation time is prolonged, the temperature of the adhered members 41, 42 during the irradiation will increase, resulting in poor heat resistance of the members.

For example, when bonding plastics, after curing the bond.

In some cases, the parts were deformed and could no longer be used as a product.

Another means to compensate for the above-mentioned drawbacks is to increase the intensity of ultraviolet rays, but this results in a rise in temperature, resulting in the same drawbacks as above.

Furthermore, it is necessary to always manage the output energy of the ultraviolet lamp 1 as a light source to be above a certain value, which makes the work that much more complicated. In addition, there was also a drawback that the quality reliability of the entire product using the adhered member after curing and adhesion was impaired.

FIG. 2 is a longitudinal cross-sectional view of the exterior of a wristwatch adhered with a photosensitive resin adhesive using the conventional continuous ultraviolet irradiation device shown in FIG. The cover glass 10 and the trunk body 11 are bonded to each other by an adhesive layer 90 made of a hardened photosensitive resin adhesive on opposing surfaces.

However, in this conventional example, since the adhesive was cured and bonded in a relatively short ultraviolet irradiation time (20 seconds) in view of work efficiency, both ends 911 and 912 of the adhesive layer 900 in contact with the atmosphere remained uncured. Each end 911 is on the outside of the watch,
The opposite end 912 is located inside the watch.

Therefore, the end portion 912 is sealed inside the wristwatch. Assuming that the depth of the uncured layer indicated by the ends 911 and 912 is W, the intensity of ultraviolet ray irradiation for curing is B, and the partial pressure of oxygen around this time is Po, the following equation approximately holds true. That is, w=kJ770π" The coefficient depends on other adhesion conditions including the irradiation time.If other conditions are the same, the longer the irradiation time is, the smaller the coefficient becomes.

That is, the longer the irradiation time, the less the depth of the uncured layer after ultraviolet irradiation is affected by the ultraviolet irradiation energy and the surrounding oxygen partial pressure. The prior art relied only on controlling two of these three effective factors of the photosensitive resin adhesive, namely the ultraviolet irradiation intensity and the irradiation time.

This not only caused a decrease in work efficiency, but also often caused the adhesive layer to remain uncured. Particularly, the unhardened end portion 912 seals and fills the inside of the watch with corrosive gas generated during the curing reaction that gradually progresses during storage, and the dial 1
The decorative silver plating layer 121 with low corrosion resistance applied to the surface of the wristwatch 20 was selectively corroded, severely damaging the appearance and easily causing extremely serious defects that would nullify the commercial value of the wristwatch as a whole.

The present invention has been made in view of the above-mentioned drawbacks, and its purpose is to provide a photosensitive resin adhesion method that has high production efficiency and is also highly reliable.

The gist of the invention is to join at least two parts by rapidly and completely curing a photopolymer adhesive while excluding ambient oxygen.

The present invention will be described in detail below based on the drawings.

FIG. 3 is a longitudinal cross-sectional view of a continuous ultraviolet irradiation device in a first embodiment of the present invention. A nozzle 3 is newly installed by penetrating a part of the cover 50 of a device similar to the vertical continuous ultraviolet irradiation device shown in FIG. It is introduced continuously at a flow rate of about 4 liters per liter.

Therefore, inside the cover 50, atmospheric oxygen is replaced by the introduced dry nitrogen gas, and the cover 50 is constantly filled with the nitrogen gas. The conveyor belt 60 is connected to the cover 5 of the irradiation device.
By the operation of the conveyor belt 60, which is continuously disposed from the outside to the inside of the 0, the adhered members 41 made of cured adhesive are continuously carried into the ultraviolet irradiation section 16, which is divided by a cover 50.

An ultra-high pressure mercury lamp is used as the ultraviolet lamp 1 so that the ultraviolet rays in the irradiation section 13 have a wavelength range of 355 nm, which is sensitive to the curing reaction of the photosensitive resin adhesive applied to the bonded portion of the adhered member 41. The irradiation energy intensity was approximately 80 mW/C. The cover 50 covers all but an inlet portion 61 and an outlet portion 62 of the conveyor belt 60, and there is a gap 51 where the belt 60 and the cover 50 contact each other.
and 52 are small, and the nitrogen gas introduced from the nozzle 3 is maintained at a slightly higher pressure than the atmospheric pressure inside the cover 50.
It is impossible for atmospheric oxygen to flow back into the interior of 0.

For this reason, the adhered member 41 carried into the ultraviolet irradiation section 16
were able to be irradiated with ultraviolet light in a state where oxygen was completely cut off. Furthermore, since the introduced and filled nitrogen is extremely dry with a dew point of -30°C or lower, it also has the effect of keeping the humidity in the atmosphere low, which is another factor that inhibits the curing reaction of photosensitive resin adhesives. It was done.

As mentioned above, by removing the factors that inhibit the curing reaction of the photosensitive resin adhesive and increasing the curing reaction speed, the conveyor belt 60
The speed of irradiation is increased from the conventional 100 cm/20.0, sec to 100 cm/80 SeC, which is 2.5 times faster than the conventional 100 cm/20.0 sec, and in addition, the conventional method of irradiating each bonded member 41 twice each is halved to once at a time. was completed.

Therefore, the efficiency of the bonding work as a whole has been improved five times compared to the conventional method. The nitrogen used is normally commercially available and the amount used is small, so it has little effect on the manufacturing cost.

FIG. 4 is a longitudinal cross-sectional view of the exterior of a wristwatch adhered with a photosensitive resin adhesive using the continuous ultraviolet irradiation device according to the first embodiment of the present invention shown in FIG. 3. cover glass 10
The opposing surfaces of the trunk body 11 are bonded to each other by an adhesive layer 90 made of a hardened photosensitive resin adhesive. Since the adhesive layer 90 is cured by a continuous ultraviolet irradiation device in the first embodiment of the present invention shown in FIG. 3, as shown in FIG. In the conventional example, the shortest UV irradiation time was 20 seconds due to the extremely low partial pressure of water vapor and blocking oxygen, but even though the UV irradiation time was much shorter than that, 4 seconds, the adhesive layer failed. 900 could be completely cured up to both ends 911 and 912 that were in contact with the atmosphere.

Therefore, in the past, since the sealed end 912 was not hardened, the silver plating layer 121 on the surface of the dial 1200 was corroded by the corrosive gas that was gradually and continuously generated from the end while the finished watch was being stored. Prevented from discoloration.

That is, even when the wristwatch according to this embodiment was continuously exposed to a light source equivalent to approximately 100,000 lux of sunlight for one year, there was no change in the dial 120.

In addition, the fixing force between the cover glass 10 and the body 11 is 20 kg.
The results showed a high value.

FIG. 5 is a longitudinal sectional view of an intermittent ultraviolet irradiation device in a second embodiment of the present invention. Ultraviolet light 2 including a wavelength of 365 nm emitted from the same ultraviolet irradiation lamp 1 as in the first embodiment is collected by a reflection plate 15 and irradiated toward a carrier 160 that moves intermittently and remains at a fixed position. .

In the carrier 160, the members 41 to be bonded, which have not yet been cured and bonded, are stored one after another in advance by hand or an automatic device, each having a T constant. Carriers similar to the carrier 160 are connected one after another at regular intervals, move intermittently once by the same distance as the aforementioned regular intervals, stop in the fixed position where the carrier 160 stopped, and stop for a fixed time. do.

At the same time as the carrier 160 and a carrier similar to the carrier 160 stop at the fixed position, the movable nozzle 14 moves close to the surface of the member 41 to be bonded before curing and bonding, and the first embodiment of the present invention is directed toward the surface. Blow out very dry nitrogen similar to that used in the example.

While the nitrogen covers the surface (the ultraviolet irradiation lamp 1 is activated and the ultraviolet rays 2 are irradiated, the photosensitive adhesive curing reaction takes place on the bonded member 41 before bonding, with oxygen in the atmosphere being blocked). Thanks to this, the process ends instantaneously, and the unbonded member 41 changes into the adhered member 42 after bonding.The time required for the adhesive curing reaction was 4 seconds.

Therefore, the work efficiency was improved five times compared to the conventional 20 seconds per irradiation. When the ultraviolet irradiation device according to this embodiment was used to bond the cover glass and body of a wristwatch similar to the wristwatch shown in FIG. 4 which was bonded with a photosensitive resin or agent, exactly the same effect was obtained.

According to the bonding method according to the present invention, the same effect can be achieved by irradiating ultraviolet rays from the edges of the adhesive layer even when the members to be bonded are entirely opaque, but if a photosensitive resin adhesive that is also anaerobic is used, it will be even more effective. The effect increases.

As stated above, the present invention has provided a photosensitive resin adhesion method that has good work efficiency and therefore has low production costs, and can produce products with a chemically stable adhesive layer and high reliability. .

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an example of a conventional continuous ultraviolet irradiation device, and FIG. 2 is a longitudinal cross-sectional view of a wristwatch exterior adhered with a photosensitive resin adhesive using a conventional continuous ultraviolet irradiation device.
Fig. 3 is a vertical cross-sectional view of a continuous type ultraviolet irradiation device according to the first embodiment of the present invention, and Fig. 4 is a longitudinal cross-sectional view of a continuous type ultraviolet ray irradiation device according to the first embodiment of the present invention, which is bonded with a photosensitive resin adhesive. FIG. 5 is a longitudinal sectional view of an intermittent ultraviolet irradiation device in a second embodiment of the present invention. 1... Ultraviolet lamp, 6... Nozzle. 41... Member to be bonded before curing bonding. 42... Member to be adhered after curing and adhesion. 5...Cover+60...Transportation belt,
90...Adhesive layer. 911... Outer end of the adhesive layer, 912... Inner end of the adhesive layer. 10...Cover glass of a watch. 11...The main body of the wristwatch. 120...Dial board. 121... Silver plating layer on the dial surface, 14...
...Movable nozzle. 160...Carrier.

Claims (3)

[Claims] (1) In the method of bonding the bonded portions of at least two parts using a photosensitive resin adhesive, the bonded portion is isolated from oxygen in the atmosphere and the photosensitive resin adhesive is cured. Photosensitive resin adhesion method. (2) The photosensitive resin bonding method according to claim 1, wherein the blocking means is to fill the container with an inert gas. (3) The photosensitive resin adhesion method according to claim 1, wherein the blocking means blows an inert gas onto the joint portion.