JPH10249103A - Method for recycling optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily separate and recover substrate resins and reflection film metals from optical disks in the form of laminating dyestuff layers, metallic reflection films and protective films on substrates. SOLUTION: The optical disks are brought into contact with an org. solvent which dissolves the dyestuff layers and does not dissolve the substrate resins to dissolve the dyestuff layers, by which the optical disks are separated to the substrates and the protective films with the reflection films. In an embodiment, the CDs-R of the structure obtd. by laminating the dyestuff layers 12, the reflection films 13 of gold and the protective films 14 of a UV curing resin on the polycarbonate substrates 11 are cut to a size of about 2cm square and the cut pieces are immersed in ethanol which is stirred for 30 minutes. Consequently, the dyestuffs are dissolved in the solvent and the cut pieces are separated to the substrate resins and the protective films adhered with the gold films (reflection films). The substrate resins are taken out of the solvent, by which the resins are recovered. The solvent is filtered to separate the protective films adhered with the gold films. The protective films are dried in the amt. The protective films adhered with the gold films after the drying are heat treated for 2 hours at 1,200 deg.C in an electric furnace, by which the gold for the reflection films is recovered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for recycling an optical disk, and more particularly to a method for separating and recovering a substrate and a reflective film from an optical disk comprising at least a substrate, a dye layer, a metal reflective film, and a protective film.

[0002]

2. Description of the Related Art An optical disk is a medium that is widely used for recording music, images, information and the like because of its high density recording capability. Above all, compact discs and optical discs belonging to the family are currently used in large quantities. Against this background, recycling of optical disks such as compact disks has begun to be considered in consideration of the recent problem of dust. Optical disks, which currently dominate the market, are read-only, such as CDs. For example, as shown in FIG. 2, a CD has a reflective film 13 of aluminum and a protective film 1 on a substrate 11 made of a polycarbonate resin.
4 are laminated in this order.

[0003] As a method of recycling an optical disk proposed so far, there is a method in which a disk is directly crushed and molded. However, in this method, components of the protective film and components of the reflective film are mixed in the molded product. For this reason, the reflection film is not recovered, and the molded product is not transparent, so that the molded product can be used only for limited applications.

As another method, there is a method in which a disk is immersed in an acid or alkali solution to dissolve the aluminum reflection film, thereby separating and recovering the protective film and the substrate, and regenerating the substrate resin. According to this method, since the recycled resin is transparent, it can be reused for a relatively wide use. However, this method has a problem that it is difficult to collect the reflection film.

[0005]

By the way, not only read-only but also recordable optical disks are available on the market. There are several types of recordable ones, but the present invention relates to at least a dye layer 12, a reflective film 13, and a protective film 14 on a substrate 11, as shown in FIG. Are stacked, and this type of optical disk is generally compatible with one-time writing. Normally, the protective film 14 is printed with ultraviolet curable ink.

[0006] Such an optical disc includes a so-called CD-R. In the CD-R, usually, a substrate of a polycarbonate resin, an organic dye such as a cyanine dye, an additive such as a quencher, a reflective film of gold or silver, and an ultraviolet curable resin such as an acrylic resin (for forming a protective film) Is used. Also, two CD-ROMs of this form
DVD having the structure shown in FIG. 4 in which R is bonded with an adhesive or the like.
There is also an optical disk called -R. In this figure, reference numeral 15 denotes an adhesive layer. In these types of discs, expensive gold and silver are used in addition to the substrate, so that the collection of the reflective film is also desired.

As a method for collecting the reflection film, it is possible to use a liquid that dissolves the reflection film as described above. However, since the reflection film is made of extremely stable gold, only a very dangerous solution such as aqua regia can be used as a solution for dissolving it. By heating the entire disk at a high temperature, organic substances such as the substrate can be burned and only the gold can be recovered, but this method does not recover the resin of the substrate. Although a method of removing the protective film and the reflective film has also been proposed, in the case of a bonded type disc such as a DVD-R, more than half of the disk needs to be removed, and thus cannot be said to be an efficient recovery method.

Therefore, the present inventor has determined that the use of an organic solvent that does not dissolve the substrate resin and dissolves the dye layer in the above-mentioned optical disk enables the reflection film and the substrate to be separated and recovered from the disk. They have found and completed the present invention.

[0009]

Means for Solving the Problems The present invention provides at least:
An optical disk comprising a substrate, a dye layer, a metal reflective film, and a protective film is contacted with an organic solvent that dissolves the dye layer and does not dissolve the substrate, thereby dissolving the dye layer to form a substrate and a protective film with a reflective film. And recycling the optical disk. The present invention is not limited to the optical disk including the substrate 11, the dye layer 12, the reflective film 13 and the protective film 14 as shown in FIG. 3, but also the optical disk of the bonding type using the adhesive layer 15 as shown in FIG. It is targeted.

In the optical disk having the structure shown in FIG. 3, it is preferable to accelerate the penetration of the organic solvent into the inner layer of the optical disk by damaging the protective film 14 and the reflective film 13. By doing so, the dissolution of the dye component is rapidly performed, and thus the peeling of the protective film with the reflective film from the substrate is promoted. The same effect can be obtained even if the disk itself is crushed and then brought into contact with a solvent. Further, it is desirable to apply an external force to the optical disk during or after the contact with the organic solvent, which accelerates the penetration of the organic solvent into the inner layer of the optical disk. Exfoliation is promoted. As a mode of applying the external force, a method of stirring the organic solvent in which the disk is immersed, or applying ultrasonic vibration to the organic solvent can be adopted.

Further, according to the present invention, when processing an optical disk whose substrate is made of a polycarbonate resin, the solubility parameter (δ value: SOLUBILITY PARAMETER) is 10 as an organic solvent, as is apparent from the results of the examples described later.
As described above, it is desirable to use one having 20 or less. When the δ value is within this range, the pigment can be dissolved without dissolving the polycarbonate substrate. If the δ value is less than 10, the polycarbonate resin dissolves, making it difficult to recover the resin. If the δ value exceeds 20, the dye cannot be dissolved, so that the separation between the substrate and the protective film with a reflective film is difficult. Can not.

Further, in the present invention, it is desirable to recover the metal material by heating the protective film with the reflection film separated by the above method to a temperature not lower than the melting point of the metal material forming the reflection film. Further, as shown in FIG.
In the case of a bonding type optical disk using the adhesive layer 15, it is preferable that the substrate is separated into a substrate and a protective film with a reflective film by a method in which the substrate is crushed and then brought into contact with a solvent.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a disk is directly or after pulverized, and brought into contact with an organic solvent capable of dissolving a dye layer (hereinafter, may be abbreviated as "solvent"). In this case, there is no limitation on the state of the disk, and it may be in a defective state, before use, or after use. The method of contact with the solvent is not particularly limited, and examples thereof include a method of immersing the disk in the solvent or a method of spraying the solvent on the disk. The solvent used is not particularly limited as long as it dissolves the dye layer and does not dissolve the substrate.

The substrate is usually made of a polycarbonate resin. Since this resin is dissolved in, for example, an aromatic organic solvent or a chlorinated organic solvent, it is desirable to use a solvent other than these. Examples of such a solvent include ethanol (δ value = 11.2) and methanol (δ value = 12.
9), isopropyl alcohol (δ value = 11.5), n
Monohydric alcohols such as butanol (δ value = 10.7); polyhydric alcohols such as 1,2-ethylenediol (δ value = 14.7) and glycerin; cellosolve solvents such as methyl cellosolve and ethyl cellosolve; Hydroxy ketone solvents such as -hydroxy-2-methyl-3-butanone, 4-hydroxy-2-butanone, and diacetone alcohol can be used. As a result, the dye is dissolved, and separation occurs at the interface between the substrate and the reflective film.

The purpose of the present invention cannot be achieved because the dye cannot be dissolved in a hydrocarbon solvent such as hexane (δ value = 7.3) or water (δ value = 21).
Acetone (δ value = 9.3) and toluene (δ value = 8.
9), when a general-purpose solvent such as acetonitrile, 2-butanone, or tetrahydrofuran (δ value = 9.1) is used, the dye is dissolved to cause the above-described peeling. Because of the penetration, it becomes difficult to regenerate the substrate resin.

In view of the above, in the present invention, an effective solvent for an optical disk whose substrate is made of a polycarbonate resin has a δ value of 10 or more and 20 or less.
In the present invention, a plurality of types of solvents having a δ value within the above range can be used as a mixture. Further, it is also possible to use a mixed liquid in which a solvent having a δ value in the above range and a solvent having a δ value outside the above range are mixed at an appropriate ratio. For example, the object of the present invention can be achieved even if a mixed solution of ethanol and water at an appropriate mixing ratio is employed. In any case, it is only necessary that the solvent used contains a solvent having a δ value in the above range.

When the disc is brought into contact with the solvent without crushing the disc, the solvent penetrates through the protective film, so that it takes time for the solvent to penetrate the dye layer, and the above-mentioned peeling proceeds efficiently. Absent. To avoid this, it is very effective to damage the protective film side of the disk in advance so that the solvent and the dye layer can come into direct contact. There is no particular limitation on the method of making the scratch, and a blade, a heating wire, a laser beam, or the like can be used. There is no particular limitation on the manner of scratching, such as the depth, arrangement and number of scratches, but it is preferable that the scratches start at the protective film side and end at the dye layer (upper to lower ends).

Further, when the disk is immersed in a solvent for the above-mentioned peeling (separation of the substrate and the protective film with a reflective film, that is, peeling at the interface between the substrate and the reflective film), the solvent is stirred and / or heated. In addition, a method of applying ultrasonic vibration to the solvent (the stirring, heating, and ultrasonic vibration of the solvent can also be used in combination) is possible, thereby promoting the peeling. As a result, it becomes easy to collect the metal material of the reflection film and the substrate resin.

The peeling between the substrate and the reflective film can also be promoted by a method in which the surface of the dye layer is rubbed with an appropriate material while the solvent is in contact with the exposed surface of the dye layer. Specifically, a method of rubbing the scratched disk surface with a cloth containing a solvent, or a method of rubbing the disk surface with a rotating brush while dripping the solvent onto the disk surface is adopted.

In the case where the above-mentioned "rubbing" promotes the separation between the substrate and the reflective film, there is no particular limitation on the material used and the shape thereof. For example, metal, plastic, rubber, cloth,
Paper, ceramics, grinding stones and the like can be used, but it is preferable that these materials are not attacked by the solvent used for peeling. For example, when these materials are dissolved in a solvent, problems such as contamination of the substrate resin may occur.

As the substrate material of the optical disk, a PMMA resin (polymethyl methacrylate), a PO resin (polyolefin), an epoxy resin, and the like are employed in addition to the polycarbonate resin. In the present invention, the solvent is also used in these cases. A resin which does not dissolve these resins but dissolves the dye is employed. Therefore, the type of the solvent can be appropriately selected in consideration of the solubility of the dye component and the solubility of the substrate material.

According to the present invention, the disk is separated into a substrate resin, a protective film having a reflective film (metal film), and a dye solution by the above processing. Depending on the above-mentioned peeling conditions, separation occurs between the reflective film and the protective film. For example, ultrasonic vibration
Since the separation between the protection films is promoted, the separation and collection of the reflection film and the protection film can be easily performed. The substrate resin separated by the peeling can be reused as a molding resin by pulverization or the like. The protective film with a reflective film is treated with a solvent or the like that dissolves and disperses the protective film, and then the resulting dispersion is filtered to separate and collect the metal of the reflective film. Also,
By performing the high-temperature heat treatment, it is also possible to decompose and vaporize the protective film component, which is an organic substance, to collect the reflective film metal. The high-temperature heat treatment is not particularly limited, and may be performed, for example, in an oven. The heat treatment temperature is also not particularly limited, and the metal can be more easily recovered by setting the heat treatment temperature higher than the melting point of the reflective film metal.

[0023]

Embodiments of the present invention will be described below. Examples 1 to 5 As an optical disc, a CD-R: CDQ-74A manufactured by Sony Corporation having a sectional structure shown in FIG. 3 was used. This disc was formed by spin-coating a coating liquid containing a dye (benzindoline-based perchlorate dye) shown in FIG. 1 on a 12-cm diameter polycarbonate substrate for CD-R, depositing gold thereon, and further depositing gold. A UV curable resin was spin-coated thereon as a protective film, and then this resin layer was cured by irradiation with ultraviolet rays. Then, the disc was subjected to the following processing.

Example 1 The above disk was cut into a size of about 2 cm square with a cutter, and the cut product was immersed in a solvent ethanol and stirred for 30 minutes. As a result, the dye began to dissolve in the solvent, and the cut product was separated into the substrate resin and the protective film to which the gold film (reflective film) had adhered. The resin was recovered by removing the substrate resin from the solvent. Further, the solvent was filtered to separate the protective film having the gold film attached thereto, and the resultant was left standing in the air and dried.

Example 2 In the same manner as in Example 1, ultrasonic waves were applied to the solvent for 10 minutes while the cut material was immersed in ethanol. As a result, the dye is dissolved in the solvent, the substrate resin, the protective film with the gold film attached,
Separated with gold powder. The resin was recovered by removing the substrate resin from the solvent. Next, the ethanol solution was filtered to separate and collect the protective film on which the gold film was adhered and the gold powder, and these were left to dry in the air.

Example 3 A 1 cm square lattice-shaped scratch was made on the protective film side of the disk with a razor. Next, it was rubbed with absorbent cotton while spraying ethanol on the protective film side. As a result, the dye was dissolved, and the protective film to which the gold film had adhered was separated from the substrate. After removing the substrate from the ethanol solution, the solution is filtered and a dye solution,
It was separated into a protective film adhered to a gold film, and the protective film was dried.

Example 4 The dried protective film of gold film recovered in Examples 1 to 3 was heat-treated at 1200 ° C. for 2 hours in an electric furnace. as a result,
The gold for the reflective film could be recovered.

Example 5 Under the same conditions as in Example 1, with respect to solvents other than ethanol, the possibility of separation at the interface between the substrate and the reflective film and the effect on the substrate resin were examined. ] And [Table 2].

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

As described above, according to the present invention, at least an optical disk comprising a substrate, a dye layer, a metal reflective film and a protective film is brought into contact with an organic solvent which dissolves the dye layer and does not dissolve the substrate. By a simple operation of dissolving the dye layer, it is possible to separate and collect the substrate and the protective film with a reflective film. In the present invention, the protective film and the reflective film are damaged, and the penetration of the organic solvent into the optical disk is accelerated to dissolve the dye component, and thus, the separation between the substrate and the protective film with the reflective film can be performed in a shorter time. It can be carried out. Further, in the present invention, during or after the contact between the optical disk and the organic solvent, by applying an external force to the disk, the separation between the substrate and the protective film with a reflective film is promoted. Recovery of the metal material can be performed more easily. Furthermore, in the present invention, the solubility parameter as an organic solvent is 10 or more, 20
By using the following, the peeling can be efficiently performed without dissolving the polycarbonate resin as the substrate material. Further, in the present invention, it is possible to recover an expensive metal material by heating the separated protective film with a reflection film to a temperature equal to or higher than the melting point of the metal material forming the reflection film.

[Brief description of the drawings]

FIG. 1 is a chemical formula of a dye constituting a dye layer of a CD-R according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a conventional CD.

FIG. 3 is a cross-sectional view showing a configuration of a conventional CD-R.

FIG. 4 is a cross-sectional view showing a configuration of a conventional DVD-R.

[Explanation of symbols]

11 ... substrate, 12 ... pigment layer, 13 ... reflective film, 14
... protective film, 15 ... adhesive layer.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Naoko Takeda 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation

Claims (5)

[Claims] 1. An optical disk comprising at least a substrate, a dye layer, a metal reflective film, and a protective film is brought into contact with an organic solvent which dissolves the dye layer and does not penetrate the substrate, thereby dissolving the dye layer and the substrate. A method for recycling an optical disk, wherein the optical disk is separated and collected into a protective film having a reflective film. 2. The method for recycling an optical disk according to claim 1, wherein the dissolution of the dye layer is accelerated by damaging at least the protective film and the reflective film. 3. The optical disk according to claim 1, wherein an external force is applied to the optical disk during or after the contact with the organic solvent to promote separation between the substrate and the protective film with a reflective film. Recycling method. 4. When the substrate is made of a polycarbonate resin, the organic solvent having a solubility parameter of 10 or more and 20 or less is used.
3. The method for recycling an optical disk according to item 1. 5. The method according to claim 1, wherein the protective film with the reflective film separated by the method according to claim 1 is heated to a temperature equal to or higher than the melting point of the metallic material forming the reflective film, thereby recovering the metallic material. Characteristic optical disk recycling method.