JPH09259472A - Optical type laminated disk, its production and apparatus for production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical type laminated disk with which the curing of an adhesive is easy and the warpage, etc., of the disk is prevented without complicating the constitution and handling of the device, and a process for producing the same and an apparatus for the production. SOLUTION: This optical type laminated disk is formed by interposing an adhesive 4 between two sheets of disks consisting of the recording disk 1A having information recorded on the sticking surface side and the printed disk 1B printed on the sticking surface side and sticking two sheets of these disks to each other. The adhesive 4 is prepd. by adding pigments which are the background color of the printed part formed on the sticking surface side to a cation polymerizable energy beam curing resin.

Description

Detailed Description of the Invention

[0001]

[0001] The present invention relates to audio information,
The present invention relates to an optical disc that optically records or reproduces video information or normal data, a manufacturing method and a manufacturing apparatus thereof.

[0002]

2. Description of the Related Art Conventionally, an optical information disc for optically reading a recording signal with a laser beam or the like is known in which two disc substrates are bonded to each other.

Recently, a thickness of 0.6, which is called DVD
A video disk is being developed in which substrates (one side) having a diameter of 12 mm and a diameter of 12 cm are bonded to the front and back. Then, the storage capacity of this disk is 4 GB or more on one surface of the bonded one. With a storage capacity of 4 GB or more, a compression movie or the like can be used to store as much as 135 minutes in a normal movie or the like. Since 90% or more of movie software is within 135 minutes, if it can be accommodated for 135 minutes, most of the movies can be accommodated on only one side of the DVD stuck together.

Therefore, the other surface (disk) pasted together may be a disk without recording signals (dummy disk). For this reason, there is a demand for printing such a CD on the surface of the dummy disk. In this case, a method of printing on the front surface side of the dummy disk and a method of printing on the back surface (bonding surface) side of the dummy disk can be considered.

In particular, since this DVD is a bonded disk, printing is performed on the bonded surface side of a transparent dummy disk, and then this dummy disk and a disk (single-sided) on which information such as a movie is recorded are bonded. The demand for matching is increasing.

This is because of the following reasons. That is, when printing is performed on the bonding surface side of the dummy disk, the printing can be seen through the transparent substrate of the dummy disk, so that irregular reflection of the surface of the printing ink is suppressed. Further, since the printing ink is not exposed on the surface, it can be seen as extremely smooth printing. For this reason, a texture closer to that of a photograph can be obtained as compared with a CD printed on the surface of a disc.

Regarding the bonding of such a DVD, there is a method of using a thermoplastic resin called a hot melt adhesive, which is used in the manufacture of laser disks. In the case of this laminating method, a hot melt adhesive is applied to the disks to be laminated by a roll coater. At this time, since the molten hot melt is attached to the surface of the roll in the coater, the roll has a surface just like an adhesive tape. With this adhesive tape-like surface, for example, when dust adheres to the disk, the roll scoops the dust.

The scooped dust enters the inside of the coater, and is sandwiched between a roll called a doctor for controlling the thickness of the adhesive and the roll to make the thickness of the adhesive uneven. . This cause often causes defects that are not coated on the coating film in a straight line (streaks in the feed direction in which the disc is coated by the roll coater). The coating defect thus generated causes a concave so-called bump-like deformation of the disc when the discs are bonded together, and causes a defect on the disc.

Even when the hot-melt adhesive is applied with such a roll coater after printing on the bonding surface side of the transparent dummy disk in advance and the adhesion between the printing ink and the disk is not sufficient, this The printing ink peels off and adheres to the roll in the roll coater to be scooped up, causing the above-mentioned problem. In particular, in the case of multicolor printing, the adhesion between various printing inks and the disc is slightly different, and the risk of peeling by the roll becomes even greater. Furthermore, the size of the ink to be peeled off depends on the design of the printing, and is much larger than that of ordinary dust.Therefore, there are many linear coating defects caused by being pinched between the roll and the doctor, and also large. Become.

Further, considering the deterioration (increasing) of the tilt due to the deformation of the disk in a high temperature environment, which is the fate of the hot melt adhesive, that is, the thermoplastic resin, D
It was not optimal to use such an adhesive and a bonding method for highly accurate bonding such as VD.

Further, a method of bonding using an ultraviolet curable resin has already been proposed in Japanese Patent Laid-Open No. 20714/1993. In this method, a UV-curing resin is applied circumferentially on a signal recording substrate placed on a holding table, then a protective substrate is superposed, and the holding table is rotated to bring the UV-curing resin to the inner and outer peripheral end surfaces. After spreading, and finally, ultraviolet rays are irradiated by an ultraviolet ray irradiation lamp to cure the ultraviolet curable resin, and the substrate and the adhesive are integrated.

When a dummy disk printed on the bonding surface side and a recording disk (single-sided) on which information such as a movie is recorded are bonded by using this method, the structure shown in FIG. 8 should be adopted. become. That is, in this structure, the one-sided disk substrate 1a having information pits formed on the bonding surface side, the aluminum reflection film 2 on the information pits, and the protective film (UV curing type) 3 covering the aluminum reflection film 2 are formed. A recording ink 1A having a recording disk 1A and a printing ink adhering portion 6 which is a design portion formed on the bonding surface of the single-sided disc substrate 1b and visible 7 through the single-sided disc substrate 1b, and formed on the printing ink adhering portion 6. In addition, a printing disk 1B ′ having a white solid printing ink adhering portion 8 serving as a background and an ultraviolet curable resin 9 for bonding the printing disk 1B ′ and the recording disk 1A are provided.

In order to manufacture such an optical laminated disc, first, as shown in FIG. 9A, the printed disc substrate 1B 'on which the design portion 6 and the white solid portion 8 are printed is set to the motor 53. Then, by opening the valve 52, the ultraviolet curing resin 9 in the pressure tank 54 is discharged onto the printing surface of the printed disk substrate 1B 'by the discharge nozzle 5.
It is dripped from 1 and attached in a ring shape.

Next, as shown in FIG. 9B, the recording disk substrate 1A having the information pits and the aluminum reflection film 2 formed thereon is placed on the ring-shaped ultraviolet curable resin 9 and the ultraviolet curable resin is applied. The resin 9 is shaken off and stretched over the entire bonding surface. Next, as shown in FIG. 9C, ultraviolet rays are emitted from the ultraviolet ray irradiator 45 to cure the ultraviolet ray curable resin 9.

[0015]

However, with the structure shown in FIG. 8, it becomes extremely difficult to cure the ultraviolet curable resin 9 which is an adhesive. For example, as shown in FIG. 7, ultraviolet rays are emitted from above the printing disk 1B ′ printed with a thickness of about 10 μm on a transparent substrate by using “DICURE SSD F27” (white) manufactured by Dainippon Ink and Chemicals as the printing ink. An ultraviolet illuminance meter 40 measured the intensity (transmittance) of the ultraviolet rays that were emitted from the irradiator 45 and transmitted through the transparent substrate 43 and the ink (aluminum reflective film) 44.

In order to measure the transmittance of ultraviolet rays, as shown in FIG. 7, an ultraviolet illuminance meter 40 including a light receiving portion 42 which is a sensor and a measurement / display portion 41 which displays based on an electric signal from the light receiving portion. To use. The print disk 1B 'or the recording disk 1A to be measured is placed on the light receiving portion 42 of the ultraviolet illuminance meter 40, and ultraviolet rays are emitted from the ultraviolet ray irradiator 45 from above the placed disk for measurement.

The intensity (transmittance) of ultraviolet rays transmitted through the transparent substrate through the printing disc 1B 'at a wavelength of 365 nm is as follows:
It was less than 0.1% which is the measurement limit of the measured measuring device. Further, the transmittance of ultraviolet rays of the recording disk 1A having the aluminum reflective film as the other substrate having a film thickness of about 55 nm was measured by the same method, and it was about 0.5 to 1%.

Therefore, in the pasting of the conventional type disc having the structure as shown in FIG. 8, since the adhesive layer 9 is located between the reflective film 2 of the single-sided disc substrate 1a and the white solid portion 8 of the single-sided disc substrate 1b. However, a large amount of energy is required to cure the resin. Incidentally, an ultraviolet curable resin "XDV-011" manufactured by Toshiba Chemical Co., Ltd., which is one of the extremely low energy curable resins whose curing light amount is said to be about 10 mJ / cm ^2.
(Viscosity 0.15 Pa · s)] as an adhesive, and when laminating the above-mentioned disc 1A having an aluminum reflection film, the ultraviolet integrated light quantity (350 nm) is 780 mJ / cm ^{2 at} a conveyor speed of 3.5 m / min. With the 1-light type UV irradiation device, the conveyor speed is 3.5 m / min.
Therefore, if the disk is not irradiated three times, it will not be cured and the apparatus will be large-scale.

Even if a heat ray cut filter is added under the ultraviolet lamp, the substrate temperature is 1 at this conveyor speed.
There is a problem in that the temperature rises to 70 ° C. or more by only irradiating once, and the substrate is thermally damaged.

Further, since such a low energy curable ultraviolet curable resin has a high reactivity, it must be handled with care. For example, in the method of applying and laminating with a spinner as shown in FIG. 9, the amount of resin applied (introduced) to the disk 1B ′ before laminating (before high-speed shaking off) is about 2 to 3 g per sheet, Only 1/10 of the resin amount remains on the bonded disks (after high-speed rotation off). In other words, almost all the amount becomes drain of the spinner, and it is necessary to recover the ultraviolet curable resin 9 from this drain and use it again for bonding from the viewpoint of cost and productivity. For that purpose, the ultraviolet curable resin 9 is prevented from reacting and causing gelation.
In the spinner part that handles the, it is indispensable to take measures such as shading. Such a device not only complicates the structure of the device but also makes the device difficult to handle.

Next, in order to attach a printing disk made of a transparent substrate having a solid white print and a recording disk having a protective film formed thereon, the above-mentioned Toshiba Chemical XDV-011 is used as an adhesive agent as shown in FIG. Coating with a spinner and shaking off so that the film thickness is approximately 40 μm (spinner rotation speed: 2500 rpm, rotation time (cutting off time): 2.5 seconds), and ultraviolet rays are irradiated (conveyor speed 3.
The tilt angle (α angle) of the bonded disc obtained by curing at 5 m / min three times had a distribution as in Comparative Example (C) of FIG. 5 (a). Here, the printing of the white solid on the transparent substrate is performed by "Daikyu SSD F27 manufactured by Dainippon Ink and Chemicals, Inc." similar to the printing disk 1B '.
(White) is formed to a thickness of about 10 μm. Also,
The recording disk has an aluminum reflective film on the information pits.
It is formed by forming a film with a thickness of 5 nm by sputtering, and coating and hardening the surface of SK-5000 manufactured by Sony Chemical Co., Ltd. as a protective film by about 10 μm.

Incidentally, when the transparent substrate on which the substrate to be bonded is not printed and the recording disk is bonded, the distribution shown in FIG. 5 (a) (B) is obtained. In addition, before the white printing (on the inside), a disc on which another color is similarly printed (two-color printing in total) and a recording disc are stuck together are shown in FIG. It became a distribution like this.

What these mean is that the transparent substrate 1b printed with the printing ink 8 warps like a bowl as shown in FIG. 6, and even if the warped disc 1b and a flat disc are bonded together. As a result, the bonded disk is not flat due to the warp of the warped disk 1b. That is, the tilt shifts in that direction.

Further, these discs were heated at 80 ° C. and 95%.
% RH, 150 hrs. When the tilt of the disk was measured by the high temperature and high humidity test of FIG.
The results of Comparative Example (C), Comparative Example (B), and Comparative Example (D) of (c) were obtained. In FIG. 5 (b), the disk was held horizontally so that the printing surface was in the upward direction, and in FIG. 5 (c), the disk was held horizontally so that the printing surface was in the downward direction.

As a result, the inventors of the present invention found that the tilt of the printed disk (B) changed in the direction of gravity when the disk was held in the test, but the printed disk (C),
In (D), it was found that the tilt changes in the shrinking direction of the ink regardless of the direction of gravity due to the hardening shrinkage of the ink over time.

Therefore, even if it is possible to bond the above-mentioned disks using a low-energy curable UV-curable resin having a curing light quantity of several mJ / cm ² , it is fatal that the tilt of the disks deteriorates with time. Have a general problem.

On the other hand, the transparent substrate printed according to the printing design has unevenness of 10 μm or more in thickness including the printing ink, and this step is sandwiched between the disks 1A and 1B 'to be bonded as shown in FIG. The thickness of the adhesive layer 9 thus formed also becomes uneven. And the ultraviolet curable resin 9 as described above
In this case, at the time of curing, a volume contraction rate of at least about 5% or more occurs, and the unevenness of the thickness of the adhesive layer 9 does not have the same step before and after curing. Discs 1A and 1A that have been bonded to each other while having different steps after curing
Since both of B'are pulled by the curing of the adhesive 9, there is also a defect that the printed pattern of the printed discs stuck together can be seen clearly floating when the aluminum reflecting surface of the recording disc is visually observed. Incidentally, the adhesive "XDV-011" has a curing volume shrinkage ratio of about 10
%, And when the thickness of the adhesive layer sandwiched between the disks by the printing ink is 40 μm and 30 μm, there is (40 × 0.1) in the step of these portions due to curing. ^{1 / 3-} (30 × 0.1) ^1/3 = 3.4
A difference of −3.1 = 0.3 μm will occur. In the case of a reflective surface, even such a level difference is sufficiently visible. For example, it may be considered that the step (depth) of the pit recorded on the compact disc, which is less than 0.1 μm, is visible to the naked eye.

The present invention has been made in order to solve the above problems, the adhesive can be easily cured without complicating the structure and handling of the apparatus, and the warp of the disk can be prevented. It is an object of the present invention to provide the above optical bonded disc, its manufacturing method and its manufacturing apparatus.

[0029]

In order to achieve the above object, the optical bonded disk of the present invention comprises a recording disk having information recorded on the bonding surface side and a printing disk printed on the bonding surface side. An optical bonded disc in which the two discs are bonded together with an adhesive interposed between the two discs, and the adhesive is formed on the bonding surface by a cationically polymerizable energy ray curable resin. It is characterized in that a pigment that becomes a background color of the printed portion is added.

Further, in the method for manufacturing an optical bonded disc of the present invention, between the two discs consisting of the recording disk on which information is recorded on the bonding surface side and the printed disk printed on the bonding surface side. 2 with an adhesive
In the method for producing an optical laminated disc for laminating two discs, the adhesive is a cation-polymerizable energy ray-curable resin, and the cation-polymerizable energy ray-curable resin is applied to the laminating surface of the two discs. It is characterized in that the two disks are pasted together after adding a pigment as a background color of the formed printed portion.

Further, in the optical bonded disc manufacturing apparatus of the present invention, it is provided between two disks, which are a recording disk having information recorded on the bonding surface side and a printing disk printed on the bonding surface side. 2 with an adhesive
In an optical bonded disc manufacturing apparatus for bonding two disks, a cationically polymerizable energy ray curable resin containing a pigment as a background color of a printed portion formed on the bonding surfaces of the two disks is added. An adhesive applying means for applying on the bonding surface of the disk;
It is characterized in that it is provided with means for superposing the pasting surfaces of the discs and means for crimping the two discs superposed together.

In the constitution of the present invention, the curing reaction, which is a characteristic of the cationically polymerizable energy ray-curable resin, is started after irradiation with energy rays. The reaction rate is relatively slow because it is not radical polymerization as in UV curable resins. That is, a cationically polymerizable energy ray (ultraviolet ray, etc.) curable resin does not cure immediately when the applied resin is irradiated with an energy ray such as ultraviolet ray, but by irradiation, the catalyst that causes a curing reaction becomes a cation. The cation is generated, and a curing reaction is performed by the cation.
Therefore, it remains liquid for several seconds to several minutes after irradiation.
Therefore, the cationically polymerizable energy ray-curable resin is still in a liquid state for a certain period of time immediately after being irradiated with ultraviolet rays,
In the meantime, it is possible to bring the two disks into contact with each other and press-bond them together.

As to the irradiation of ultraviolet rays, as described above, it is possible to directly irradiate the cationically polymerizable energy ray curable resin with ultraviolet rays, rather than irradiating ultraviolet rays through aluminum of the disk as in the conventional ultraviolet curable resin. Can be simplified. In addition, the handling precautions when using a highly reactive UV-curable resin are unnecessary, and the thermal damage caused during curing can be suppressed to an extremely low level.

[0034]

Embodiments of the present invention will be described below with reference to the drawings. According to the present invention, a transparent substrate (polycarbonate) molded in the same process as a CD (compact disc) is printed on the surface side so that it looks like a true character (printing disc) on the surface side, and the other one is laminated. A disc and a recording information-formed disc (recording disc) having a reflective film and its protective film formed in the same process as the CD are bonded together by using a cation-polymerizable energy ray-curable resin as an adhesive, and a cation used at that time. TECHNICAL FIELD The present invention relates to an optical laminated disc, which is characterized by using a polymerizable energy ray-curable resin as a base color for printing of a printing disc, a method for producing the same, and an apparatus for producing the same.

FIG. 1 is a sectional view of an optical laminated disk according to the present invention. Such an optical bonded disc is used as an adhesive 4 that shares adhesion with ink for the purpose of whitening the base of a multicolored printing (design section). 100 parts by weight of "95A45X" manufactured by K.K. Co., Ltd. and 10 parts by weight of barium sulfate as a pigment and 6 parts by weight of talc were blended (viscosity 3 Pa · s).

First, a printing disk 1B having a printing ink adhering portion 6 which is a multicolored design portion and a reflecting film 2,
An adhesive 4 having a thickness of approximately 10 to 30 μm is applied to each of the recording disks 1A having the protective film 3 formed thereon by screen printing or the like. Then, ultraviolet rays are used as the energy rays, and after irradiation with the ultraviolet rays, they are brought into contact, pressure-bonded and pressed to manufacture. In FIG. 1, reference numeral 4 a is a bonding surface of the adhesive 4. The white background color has the effect of excellent color development in the print design section.

FIG. 2 is a diagram showing an embodiment of an optical bonded disc manufacturing apparatus. In FIG. 2, a disk (single disk) is supplied to the disk supply positions 10a and 10b from the upstream portion of the manufacturing process for bonding. In the case of the embodiment, aluminum is formed as a reflective film in the information pit at the disc supply position 10a, and an ultraviolet curable resin such as SK-5000 manufactured by Sony Chemicals Co., Ltd. is formed as a protective film on the surface thereof. The recording disc 1A, which is a single disc, is supplied. Further, the printing disk 1B, which is a single disk on which multicolor (design) printing is performed except for the white color of the background, is supplied to the disk supply position 10b.

The supplied recording disk 1A and print disk 1B are supplied by the disk supply arm 12 to the supply position 1
0a and 10b to turntables 13a and 13b, respectively
Moved to

The turntables 13a and 13b are rotated by equally divided pitches, and the cationically polymerizable energy ray curable resin "95A45X1" is applied to each of the disks at the adhesive print applying sections 14a and 14b which are adhesive applying means. Screen print on the area of φ25 to φ118 mm.

After printing and coating, the coating disk is rotated one pitch further, the disk is taken out from the rotary tables 13a and 13b by the application disk take-out arms 15a and 15b, and an ultraviolet irradiation carrying table (hereinafter referred to as a UV carrying table) 17 is provided.
Moved to The UV transfer table 17 allows the two transferred disks 1A and 1B to be placed under the UV irradiator 18 at a constant speed. The ultraviolet ray irradiator 18 irradiates the cationically polymerizable energy ray curable resin with a certain amount of ultraviolet rays.

In the embodiment, the moving speed is 5.5 m /
At min, the integrated quantity of UV light with a wavelength of 350 nm is 500
5.5 m by using the ultraviolet irradiator 18 with mJ / cm ²
As a result of irradiating the applied cationically polymerizable energy ray-curing resin with ultraviolet rays by moving the UV transport table 17 at a speed of about 1 / min, gelation of the resin starts in about 15 seconds after irradiation and solidification occurs in about 2 minutes thereafter. The practical hardness was exhibited in about 5 minutes.

Disks 1A and 1B irradiated with ultraviolet rays
The UV transport table 17 temporarily stops at the passage exit position of the ultraviolet irradiator 18, and at this position, the pickup arms 19a and 19b take out the UV transport table 17 from the UV transport table 17, and the tips of the disc stacking portion 21a and the disc reversing arm 22. It is transferred to the disc reversing unit 21b attached to the. Here, the two disks are brought into contact with each other as follows.

FIG. 3 is a view showing a disc superposing device 30 which is means for superposing the pasting surfaces of two discs. In FIG. 3, the disc overlapping portion 2
1a descends through a slide mechanism such as an air cylinder 30a and a shaft 30b with the disk temporarily placed after the disk is transferred, and at the same time, the disk reversing section 21b holds the transferred disk and the rotary actuator 28 or the like. It rotates 180 degrees with respect to the horizontal plane via the rotation mechanism section of. After that, the disc reversing arm 22 moves so that the reversed disc reversing portion 21b is located above the disc superposing portion 21a, and then the disc superposing portion 21a is raised to its original height, so that the two discs are removed. Contact (overlap). After the contact, the disc overlapping portion 21a once descends together with the two discs, and then the disc reversing arm 22 moves (retracts) to the original position. At the time of this contact, the disks are superposed by the fitting pins 26 without eccentricity, and fixed without being displaced by the viscosity of the applied resin.

Disc 1 thus laminated
Next, A and 1B are transferred to the vacuum press parts 24a and 24b by the disk transfer arm 23 of FIG. The disc transfer arm 23 has its arm center so that when one arm is positioned at the disc stacking portion 21a, the other arm is positioned at the disc stacking portion 25, which is the discharge location of the completed discs at the same time. In addition, when one arm is located in the vacuum press section 24a, the other arm is located in the vacuum press section 24b, and the normal standby position is a position that does not interfere with the operation of the other arm or part. The rotation pitch is given so that

FIG. 4 is an explanatory view of the vacuum press parts 24a and 24b which are means for press-bonding two superposed disks. In FIG. 4, the stacked disks 1A,
After 1B is transferred onto the lower pressure bonding plate 31, the upper vacuum chamber (upper lid) 32 of the vacuum press section is moved to the upper pressure bonding plate 33.
It descends together with the lower vacuum chamber (base plate) 34 and contacts with the O-ring 35 interposed, and then temporarily stops (at this time, the disks 1A, 1B and the upper pressure bonding plate 33 are not in contact with each other, and a slight gap is formed. The vacuum valve 36 is opened, and the vacuum pump 37 evacuates the inside of the vacuum press unit system. After that, the upper pressure plate 33 is further lowered, and the disks 1A and 1B are press-pressed.

As the conditions at this time, the cationically polymerizable energy ray-curable resin was irradiated under the ultraviolet irradiation conditions, transferred to a vacuum press section within 5 seconds after irradiation, and a series of operations were performed. After evacuation to the following (2 seconds in the case of the embodiment), as a cushioning material per piece on the crimping surfaces of the crimping plates 31 and 33, "C" manufactured by Daiichi Race Co., Ltd.
IEGAL 7355-OFF ”1.35 mm thick is stuck and pressure of 2 kg / cm ² is applied to the disc surface.
With the condition of pressing for 5 seconds, flat bonding was possible in which almost no air bubbles remained on the adhesive surface caused by screen printing.

After pressing in this way, the vacuum valve 36 is closed, the leak valve 38 is opened to return the inside of the vacuum press system to the atmospheric state, and the upper vacuum chamber (upper lid) 32 is raised together with the upper pressure bonding plate 33. The reason why two vacuum press sections are installed is a tact problem of the embodiment and is not related to the number thereof.

Next, the bonded disks 1A and 1B
2 are sequentially taken out from the vacuum press parts 24a and 24b by the disk transfer arm 23 of FIG.
Discharge and accumulate. The adhesive disks 4 of the bonded disks 1A and 1B1b ejected to the disk stacking unit 25 are not completely solidified, and therefore the disks 1A and 1B are required to maintain flatness.
It is advisable to supply flat spacers between them.

As another embodiment, the rotary table 1
By increasing the division pitch of 3a and 13b, a transparent single disk and a recording disk single disk on which aluminum is formed by sputtering etc. and a protective film is not applied are supplied as supply disks, and the rotary tables 13a and 13b are used. Various devices of the disc manufacturing process are omitted by the device configured to print the design part and apply the protective film of the aluminum film at the increased division pitch before the adhesive printing of the cationically polymerizable energy ray curable resin is applied. It can be done easily.

As described above, the laminated disks 1A and 1B on the inner surface of which a multicolor printing is performed based on a white background are easily and stably mass-produced. The bonded discs 1A and 1B manufactured in this manner are printed in comparison with those printed on a normal disc surface because the inner surfaces of the bonded discs 1A and 1B are multicolor printed on a white background. It can be a disc with a surface having just the photo-like texture print without the surface roughness of the ink. Further, since the layers are laminated by vacuum pressing, an extremely flat laminated disk can be obtained in which the adhesive layer contains almost no bubbles.

According to the present invention, the characteristic feature of the cationically polymerizable energy ray-curable resin is that the curing reaction is initiated after irradiation with energy rays, and the reaction rate is not radical polymerization as in UV-curable resins. The fact that curing proceeds relatively slowly can be used. For example, when "95A45X1" manufactured by Sony Chemicals Co., Ltd. is used, 500 mJ of ultraviolet rays are used as energy rays at a wavelength of 365 nm.
/ Cm ^{2 When} this resin is directly irradiated, it takes about 15 minutes for the resin to gel (curing begins) and then the reaction proceeds and the original strength of the resin appears.
The resin is still in the liquid state for about 30 seconds immediately after the irradiation with the ultraviolet rays, and during this time, two disks can be brought into contact with each other and pressure-bonded to each other.

As described above, the irradiation of ultraviolet rays can be performed directly without irradiation of ultraviolet rays through the aluminum of the disk as in the conventional ultraviolet curable resin, so that the ultraviolet irradiation device can be simplified. In addition, the handling precautions when using a highly reactive ultraviolet curable resin are not required, and not only the apparatus can be simplified but also the thermal damage caused during curing can be suppressed to an extremely low level.

In addition to the contents described above, the effect of this embodiment is that since the surface of the cationically polymerizable energy ray-curable resin is directly irradiated with ultraviolet rays, the post-curing (curing with time) of the printing ink is performed at this point. In addition, the tilt of the bonded disks does not change due to the subsequent curing shrinkage of the ink. The results showing this are shown in FIGS.
Note that FIG. 5 shows the tilt angle in the radial direction of the disk in various manufacturing methods.

In FIG. 5, A shows the case of a laminated disk without printing according to the present invention, B shows the case of a laminated disk without printing according to a comparative example (another adhesive), and C shows a comparison. The example shows a case of a laminated disk having an inner surface 1 color printed by an example (other adhesive), D shows the case of an inner surface 2 color printed laminated disk by a comparative example (another adhesive), and E shows an example of the present invention. The case of a laminated disk with two-color printing on the inner surface is shown.

Further, the volumetric shrinkage rate at the time of curing is small (4% or less) as in the case of the above-mentioned UV-curable resin, and further, if the resin is applied by, for example, screen printing, the above-mentioned UV-curable resin is cured. Since uneven thickness (unevenness) of the adhesive layer due to the printing ink as in the case of mold resin is alleviated,
It is also possible to eliminate the defect that the printed pattern of the printed disks that are stuck together is clearly visible when the aluminum reflective surface of the recording disk is viewed.

As described above, the apparatus is not only capable of simplifying and simplifying the apparatus, but also can perform bonding and printing of the base color at the same time, and the bonded disk is a disk whose tilt change is extremely small. It can be offered inexpensively, in large quantities, and stably. Furthermore, according to the method of the present invention, it is also possible to use the ink for multicolor printing by appropriately coloring the cationically polymerizable energy ray-curable resin used.

In the above embodiments, the background color pigment is white, but pigments of colors other than white may be used. Further, in the above-mentioned embodiment, the cationically polymerizable energy ray-curable resin containing the pigment is applied to both the disks to be bonded, but it may be applied to only one disk.

[0058]

As is apparent from the above description, according to the present invention, between two discs consisting of a recording disc having information recorded on the bonding surface side and a printing disc printed on the bonding surface side. As the adhesive to be interposed, a cationically polymerizable energy ray-curable resin to which a pigment that becomes the background color of the printed portion is added is used, so it is easy to directly irradiate the adhesive with energy rays. Further, since it is not necessary to increase the output of the energy ray source or lengthen the irradiation time, the device is not enlarged and the substrate is not thermally damaged, and the handling is easy. Further, there is an effect that it is possible to prevent deterioration of the tilt of the disc with time.

[Brief description of drawings]

FIG. 1 is a sectional view of an optical bonded disc according to an embodiment of the present invention.

FIG. 2 is a diagram showing an embodiment of an optical bonded disk manufacturing apparatus.

FIG. 3 is a diagram showing a disc stacking device in the optical bonded disc manufacturing device of FIG. 2;

FIG. 4 is an explanatory diagram of a vacuum press unit that is a means for press-bonding two discs that are stacked.

FIG. 5 is a diagram showing tilt angles in a radial direction of a disc in various manufacturing methods.

FIG. 6 is a diagram for explaining a warp of a disc due to printing.

FIG. 7 is a diagram showing an ultraviolet transmittance measuring device.

FIG. 8 is a cross-sectional view of a conventional optical bonded disc.

FIG. 9 is a diagram showing a conventional method for manufacturing an optical bonded disc.

[Explanation of symbols]

 1A Recording Disc 1B Printing Disc 4 Adhesive 14a Adhesive Printing Coating Section (Adhesive Coating Means) 14b Adhesive Printing Coating Section (Adhesive Coating Means) 24a Vacuum Pressing Section 24b Vacuum Pressing Section 30 Disk Stacking Device

Claims (3)

[Claims] 1. An adhesive agent is interposed between two discs consisting of a recording disc on which information is recorded on the bonding surface side and a printing disc printed on the bonding surface side.
In an optical laminating disc obtained by laminating a plurality of discs, the adhesive is a cationically polymerizable energy ray curable resin to which a pigment that becomes a background color of a printed portion formed on the laminating surface is added. An optical bonded disc characterized in that 2. An adhesive agent is interposed between two discs consisting of a recording disc on which information is recorded on the bonding surface side and a printing disc printed on the bonding surface side, and the two disks are bonded together. In the method for producing an optical bonded disc to be combined, the adhesive is a cationically polymerizable energy ray curable resin, and a printed portion formed on the adhered surface of the two disks by the cationically polymerizable energy ray curable resin. The method for producing an optical disc, wherein the two discs are pasted together after adding the pigment that becomes the background color. 3. An adhesive agent is interposed between two discs consisting of a recording disc on which information is recorded on the pasting face side and a printed disc printed on the pasting face side, and the two discs are pasted together. In an optical bonded disc manufacturing apparatus for matching, a cationically polymerizable energy ray-curable resin to which a pigment that becomes a background color of a printed portion formed on the bonding surfaces of the two disks is added is bonded to the bonding surface of the disks. An optical sticking device comprising: an adhesive applying device for applying an upper surface; a device for superposing the pasting surfaces of the two discs; and a device for crimping the two discs superposed on each other. Equipment for manufacturing laminated discs.