JPS60125945A - High density information recording carrier and its production - Google Patents

Abstract

PURPOSE:To obtain an adhesion layer uniform in thickness and strong in adhesive strength by bonding two plastic disks containing an information recording layer on a single side of one of both disks to each other via a film or sheet type adhesive. CONSTITUTION:Two plastic disks 6 and 6 containing an information recording layer 5 on a single side of one of both disks are bonded to each other with the layer 5 put inside via a film or sheet type adhesive 1. Then the heat and pressure are applied to both disks 6 from outside to put them together in a body. For the adhesive 1, it is desirable to use a hot-melt adhesive or a pressure-sensitive hot-melt adhesive with or without a core 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is applicable to high-density information recording carriers such as video discs in which information is recorded as submicron-order bits, opto-magnetic recording media, and state changes such as chalcogenide;
In particular, it relates to plastic information storage carriers and their manufacturing methods. More specifically, the present invention relates to an improved method for bonding two plastic disks, at least one of which has an information recording layer formed on one side, and a high-density information storage carrier produced thereby. It is something.

It is known to use two of the plastic discs bonded together in order to protect the information recording layer or to reinforce the plastic disc itself. In this known lamination method, 2
Two plastic discs are bonded together using ultraviolet irradiation resin, or liquid adhesive. When using this liquid adhesive, a coating device such as a coating/coater is required, and
In the case of air-circuit/doinoch type discs, special measures are required to prevent the adhesive from adhering to the information recording layer, and the UV curing time increases, resulting in poor workability.
Poor productivity. In addition, if the adhesive layer has a uniform thickness and the adhesive layer is stable and a spacer is not necessary, a separate spacer must be prepared. Furthermore, if the plastic disks to be bonded are deformed, even if they are compressed and bonded together, there is a drawback that they will deform again over time.

A first object of the present invention is to provide a high-density information recording carrier having an adhesive layer with uniform thickness and strong adhesive force, which overcomes the above-mentioned drawbacks.

Another object of the present invention is to provide a method for manufacturing a laminated high-density information recording carrier without re-deformation or post-deformation.

Simply put, the high-density information recording carrier according to the present invention is a high-density information recording carrier made by laminating two plastic disks, each of which has an information recording layer on one side of at least one plastic disk, to each other with the information recording layer facing inside. The present invention is a high-density information recording carrier characterized in that the two plastic disks are bonded together via a film-like or sheet-like adhesive.

The film-like or sheet-like adhesive is preferably a hot-melt adhesive, a pressure-sensitive hot-melt adhesive, or a combination of the two.

The film or sheet adhesive may bond the entire inner surface of the disk to each other,
It can also be constructed by an outer annular adhesive ring and an inner adhesive ring that join the outer and inner peripheries of both plastic discs to each other.

A high-density information recording carrier according to another embodiment of the present invention is a high-density information recording carrier in which two plastic disks having an information recording layer on one side of at least one plastic disk are laminated together with the information recording layer on the inside. In the information record carrier,
The high-density information recording carrier is characterized in that the two plastic discs are bonded to each other via a film-like or sheet-like adhesive that is spread on both sides of a core material.

The film or sheet adhesive is preferably a true melt adhesive, a pressure-sensitive true melt adhesive, or a combination of the two.

The film-like or sheet-like adhesive may be one that bonds the entire inner surfaces of the disks to each other, but it may be constituted by an outer circumferential adhesive link and an inner circumferential adhesive ring that bond the outer and inner circumferences of both plastic disks to each other. You can also do it.

The core material can be made of paper, plastic, metal such as aluminum, duralumin, steel, or a reinforced resin composite material reinforced with glass fiber, carbon fiber, or the like.

The method for producing a bonded high-density information recording carrier according to the present invention involves bonding two plastic disks, each of which has an information recording layer on one side of at least one plastic disk, to each other with the information recording layer on the inside. The method for manufacturing an information recording carrier is characterized in that a film or sheet adhesive is interposed between the two plastic disks, and then heat and pressure is applied from the outside of both plastic disks to integrate the two plastic disks. This is the method to do so.

The heating and pressing described above can be carried out under annealing conditions to correct deformation of the plastic disc.

As the above-mentioned film or sheet adhesive, it is preferable to use a hot melt adhesive and/or a pressure-sensitive hot melt adhesive with or without a core material.

The plastic disc used in the high-density information recording carrier to which the present invention is directed is generally made of acrylic resin, polycarbonate resin, etc., and information is recorded on at least one side thereof. This information layer is read only (Read 0n
ly ) type, writeable (DRAW) type, or erase-rewritable (E-DRAW) type. The information reading method may be either a front-side reading method or a back-side reading method, and the detection method may be one using light or electrostatic capacitance. In any case, the invention is applicable to any high density information storage carrier.

The sheet-like or film-like adhesive according to the present invention may be any self-supporting sheet-like or film-like adhesive, taking into consideration its adhesion to the plastic disc and/or straddle core material to be laminated, and its heat resistance. Any material known in the art can be selected.

This sheet adhesive is preferably a true melt type or pressure sensitive type hot melt adhesive. In general, true melt adhesives contain waxes, plasticizers, etc. in addition to the base resin.
It contains adhesion promoters, fillers, antioxidants, etc., and may be thermosetting or crosslinked. These hot melt adhesives and pressure-sensitive true melt adhesives are easily available commercially.

The sheet-like adhesive or film-like adhesive of the present invention can be used in various forms, some specific examples of which are shown in FIG. Figure 1-(A) shows when hot melt adhesive film 1 is used as is, Figure 1-(B) shows when release paper 2 is attached to real-melt adhesive film 1, Figure 1-(C) shows is pressure sensitive hot melt adhesive 3 and release paper 2
Fig. 1-(D) shows the structure of pressure-sensitive real melt adhesive 3/hot melt adhesive l/release paper 2, and Fig. 1-(E) shows real melt adhesive on both sides of the core material 4. The one with melt adhesive 1, Fig. 1-(F) is the same as Fig. 1-(E).
Figure 1-(G) with release paper 2 added to the above.
Figure 1-(H) has a composition of pressure-sensitive hot melt adhesive 3/core material 4/hot melt adhesive 1/release paper 2.
Figure 1 shows the composition of pressure sensitive hot melt adhesive 3/core material 4/pressure sensitive pot melt adhesive 3/release paper 2.
(I) has a composition of pressure-sensitive hot melt adhesive 3/bott melt adhesive 1/core material 4/hot melt adhesive 1/release paper 2. Obviously, configurations other than these are possible.

The method of laminating two 7-last disks includes a sand one-inch type in which they are laminated in close contact with each other, and an air-sand inch type in which a space is interposed in between, and the present invention can be applied to either of them. It is sufficient that the information layer is formed on at least one of the plastic discs, and the other may be a protective plastic disc that does not have an information layer.

FIG. 2 shows a disk with a Germanic structure in which two plastic disks 6.6 each having an information layer 5 are laminated together using the sheet-like adhesive shown in FIGS. 1-(E) to (I). This disk is made by heating and pressing two plastic disks 6°6 together using a sheet adhesive. The pressure, temperature, and time in this case vary depending on the type of sheet adhesive used and the type of plastic disk, but in general, the pressure is 05 to 15 kg/+:J, and the temperature is 50 to 100°C1.
The pressurization time is selected to be about 15 to 300 seconds.

The sheet or film adhesive of the present invention can be used together with a core material. This core material serves as a spacer, reinforcing material, etc. This core material can be combined with sheet-like or film-like adhesives in various forms, specific examples of which are shown in FIGS. 1(E) to 1(I). In reality, the film or sheet adhesive and the core material are separated,
Although they may be combined by being placed one on top of the other at the time of lamination, workability is improved if the two are integrated in advance to form a sheet-like sheet as a whole. In the latter case, a sheet-like or film-like adhesive may be pressed onto both or one side of the elongated body, which is the raw material for the core material, to form a laminate. fruit! As shown in FIG. 3, a sheet adhesive 1, 1 is applied to both sides of the core material 4 using a hot roll 10. ]
It is sufficient if they are crimped and integrated using O.

The material of the core material 4 is cardboard, paper such as rayon paper, any plastic material, aluminum, metal such as steel, F R1
) can be selected from composite materials such as When punching the plastic disk to the same size as the punch 11 shown in FIG. 3, it is of course necessary to select a material that can be punched.

In the case of a core that cannot be punched out, a sorted or film adhesive is laminated on the second half of a disc-shaped core that has been pre-processed to the same dimensions as the plastic disc, as shown in Figure 3, and only the adhesive layer is left on. It may be punched out to the same size as the plastic disk, or hot melt adhesive may be applied to the core using a well-known true melt coater. In this case, a release paper may be attached to the outer surface of the adhesive as appropriate.

Figure 4 shows an example of an air sand inch type disk, in which case the punch shown in Figure 3 can be changed to remove the circumferential spacer
The guar and outer circumferential spacer ring 8 may be punched out, and both spacers may be laminated and integrated between two plastic disks 6, 6. Other points are similar to the embodiment shown in FIG.

FIG. 5 shows an embodiment of another structure of the air sand inch type, in which the U core material 4 has the same dimensions as the one in FIG. 2, and is bonded inside and outside with gua.

8 are placed on its inner and outer peripheries. In order to make a disk having this structure, it is necessary to separately stamp and manufacture the inner and outer circumferential rings 7, 8 of film or sheet adhesive and the donut-shaped core material 4.

When integrating two plastic discs and a sheet adhesive, as shown in FIG. 6, insert the notebook adhesive 7, 8 and both plastic discs 6, 6 and center ring. A ring 15 can also be used to define the outer diameter if necessary. These centering jigs 1.4, 1
5 may be integrally formed on the lower support plate 13 or may be attached separately. In actual bonding, an assembly consisting of two plastic disks, a sheet adhesive and/or a core material is placed on the lower support plate 13, and is bonded by pressure and heat using the upper support plate 12. Heat and press these support plates],
2.Although it may be carried out directly according to 1.3, a plurality of units consisting of two upper and lower support plates] 2.13 may be stacked or placed in parallel in a press machine and heated and pressed at the same time, or sequentially transferred to a press machine. , heat and pressure may be applied.

Bonding temperature and H-force are important factors in laminating disks, which is the subject of the present invention.

That is, the bonding conditions for sheet-like hot melt adhesives that are generally commercially available are: temperature 80 to 130°C, pressure j to 5.
kg/oa and the pressurization time is 10 to 60 seconds, but in the case of an acrylic resin disk, if a temperature of 80° C. or more is applied, the submicron-order recording layer will disappear. Therefore, in the case of acrylic resin discs, the lamination temperature is 50 to 70°C and the pressure is 5 to 5 kg/cut.
, it is preferable to set the pressurization time fd to 60 to 120 seconds.

If these conditions are exceeded, problems such as damage to the recording layer and poor adhesion will occur. In the case of polycarbonate resin, the lamination temperature can be raised to 50 to 100°C.

The thickness of the sheet-like or film-like adhesive of the present invention is not particularly limited, but is generally selected to be about 50 to 300 μm in consideration of adhesive strength, precision, etc.

Further, the thickness of the core material can be appropriately selected depending on the material. For example, in the case of an aluminum plate, it can be about 0.5 to 2.0 mm.

One of the advantages of using the bonding method of the present invention is that even if the plastic disk is deformed, the distortion of the plastic disk is corrected by the heating and pressing effect (annealing).
It is possible to do so.

Generally, when performing this annealing, the heating plate 12°13
The zero temperature is preferably lower than the glass transition point of the resin. In the case of an acrylic resin disk, for example, it can be annealed at about 75°G, and the annealing time is 30°G.
“In minutes to 5 hours”: Yes.

The present invention will be explained below using specific examples.

Example 1 Film adhesive with a thickness of 100μ (X manufactured by Kurashiki Boseki Co., Ltd.)
4360) was punched out into a donut-shaped disk with an inner diameter of 35 lines and an outer diameter of 300 mm, and placed between two plastic disks made of polymethyl methacrylate having an information layer.
Pressure 5 kg / between the upper and lower heating plates heated to °C
It was crimped with crl for 2 minutes.

No peeling was observed in the thus obtained laminated disk even after it was left in an atmosphere of 700C for 2/I hours.

Example 2 (core material included/t-shaped adhesive) Thickness 17 on both sides of an aluminum plate with a height of 1.2 m and 7 nm.
A sheet hot melt adhesive No. 071 (Nitto Denko@M-5200) was crimped using the apparatus shown in FIG. In this case, the roll temperature U' ] O0°C1 The drawing speed is 8
m/min. Using a punch, the obtained sheet hot melt adhesive containing core material was used to form a 1-naso-shaped outer spacer link with an inner diameter of 280 m 1π and an outer diameter of 3.0O 17H, and an inner spacer link with an inner diameter of 35 mm and an outer diameter of 90++++π. Place the punched pieces between two polymethyl methacrylate plastic disks and make 600 pieces each.
The obtained air sand isoti-structured disk was pressed for 2 minutes between heating plates heated to 0.
(No female elephant was born when I pierced the open side of M, 1f94, Higashima Station 1.

Example 3 (In the case of annealing) Sheet adhesive with a thickness of 80 μm (M-5 manufactured by Nitto Denko Corporation)
251) into donut-shaped disks with an inner diameter of 15 mm and an outer diameter of 200 mnt, which were sandwiched between two slightly ribbed polymethyl methacrylate disks.
5 kg/c between upper and lower heating plates heated to 5°C
Heat and pressure annealing was performed for 1 hour under a pressure of RL.

The thus laminated disks were placed in an atmosphere of 70°G for 24 hours.
Even after being left for an extended period of time, the outermost peripheral portion of the disk was only warped with respect to the reference surface. On the other hand, in the case of a disk simply glued with epoxy resin, the same test method
．． Show the 85 mm warp.

The present invention has been explained above using special embodiments (7.
The present invention is not limited to this, and various changes and improvements can be made without departing from the spirit of the present invention. In particular, in order to make the bonding process continuous, the lower support plate 1
It is also possible to fully automate the cutting and lamination of the sheet-like adhesive and/or core material by transporting the material by a processing/dressing belt.

The advantages of the present invention are summarized as follows:]) The inherent advantages of film-like or sheet-like adhesives, such as being solvent-free, pollution-free, and easy to handle, can be used as is.

2) The lamination speed and adhesion speed can be increased compared to liquid adhesives.

3) Thickness can be easily controlled and made uniform.

4) Peel strength is higher than double-sided adhesive tape.

5) It can be bonded at a lower temperature than a coating-type (pressure-sensitive) hot melt, and has good thermal properties.

6) Annealing can also be performed at the same time.

At this time, the presence of the adhesive layer forms a cushion layer, which prevents thermal deformation of the information layer.

7) It becomes easy to create a mass production line for discs.

[Brief explanation of drawings]

FIG. 1 is a view of various examples showing the layer structure of the sheet-like or film-like adhesive and the core material used in the present invention. FIG. 2 is a sectional view of a Sanderuch-type disk according to the present invention. FIG. 3 is a conceptual diagram showing a method for producing a sheet-like film adhesive of the present invention. FIG. 4 is a sectional view of an air sand type disk according to the present invention. FIG. 5 is a sectional view of another type of air sensor/doisochi type disk according to the present invention. FIG. 6 is a conceptual cross-sectional view of a pot showing a method of manufacturing the above-mentioned disk. (Symbols in the figure) 1° Adhesive film, 2: Release paper, 3° Pressure-sensitive hot melt adhesive, 4. Core material, 5: Information layer, 6, Plastic disk, 7 Center pi/, 8° outer diameter specification/g. Patent applicant: Daicel Chemical Industries, Ltd. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] l) A high-density information recording carrier in which two plastic disks, at least one of which has an information recording layer on one side, are bonded together with the information recording layer on the inside, A high-density information recording carrier comprising two plastic disks bonded together with a film or sheet adhesive. 2) Claim 1, characterized in that the film-like or sheet-like adhesive is a hot melt adhesive or a pressure-sensitive real melt adhesive - an adhesive that is a combination of both ter and straw. The high-density information recording carrier described in Section 1. 3) The high-density information recording carrier according to claim 1 or 2, wherein the film-like or sort-like adhesive bonds the entire inner surfaces of both the discs to each other. 4) Claim 1, characterized in that the film-like or sheet-like adhesive is constituted by an outer annular adhesive ring and an inner adhesive ring that join the outer and inner peripheries of both discs to each other. Or the high-density information recording carrier according to item 2. 5) In a high-density information recording carrier in which two plastic disks each having an information recording layer on one side of at least one plastic disk are pasted together with the information recording layer facing inside, the two plastic disks are the core. A high-density information recording carrier characterized in that the materials are bonded to each other via a film-like or sheet-like adhesive provided on both sides of the material. 6) Claim 5, characterized in that the film or sheet adhesive is a true melt adhesive, a pressure-sensitive pot melt adhesive, or a combination of both. The high-density information recording carrier described above. 7) High-density information according to claim 5 or 6, characterized in that the film-like or sheet-like adhesive bonds the entire inner surface of the disk to each other. record carrier. 8) The film-like or sheet-like adhesive is constituted by an outer periphery adhesive/glue and an inner periphery adhesive ring that join the outer and inner peripheries of both disks to each other. The high-density information recording carrier according to any one of Item 5 and Item 6. 9) Claim No. 9, characterized in that the core paulownia is constituted by an outer core ring and an inner core ring having radial dimensions corresponding to the outer adhesive ring and the inner adhesive ring. The high-density information recording carrier according to item 8. 10) The core material is paper; plastic; aluminum;
The high-density information recording carrier according to claim 5, characterized in that it is made of a reinforced resin composite material reinforced with a gold layer of duralumin, steel, etc., or glass fiber, carbon fiber, etc. 11) In a method for producing a high-density information recording carrier by laminating two plastic disks having an information recording layer on one side of at least one plastic disk to each other with the information recording layer facing inside, the method comprises: A method characterized by interposing a film or sheet adhesive between plastic disks, and then applying heat and pressure from the outside of both plastic disks to integrate both plastic disks. 12) The method according to claim 10, characterized in that said heating and pressing is performed under annealing conditions to correct deformation of the plastic disk. 13) Claim 10, characterized in that a true melt adhesive and/or a pressure-sensitive hot melt adhesive is used as the film-like or sheet-like adhesive with or without a core material. or the method according to paragraph 11.