JP3528898B2 - How to recycle optical discs - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recycling an optical disk, and more particularly to a method for recovering a dye component from an optical disk including at least a substrate, a dye layer, a reflective film and a protective film.

[0002]

2. Description of the Related Art An optical disc is a medium that is widely used for recording music, images, information, etc. because it can perform high density recording. Among them, compact discs and optical discs belonging to the family are currently used in large quantities. Against this background, in consideration of the recent dust problem, recycling of optical discs such as compact discs has begun to be considered. Optical disks, which currently occupy most of the market, are read-only disks such as CDs,
On the other hand, recordable optical discs are also on the market.

There are several types of recordable ones, but the one relevant to the present invention is the dye layer 12 and the reflection film 1 on the substrate 11 among them as shown in FIG.
3 is an optical disc in which the protective film 14 and the protective film 14 are laminated, and this type of optical disc normally supports writing only once. It should be noted that the protective film 14 is usually printed with ultraviolet curable ink.

One of such optical discs is called a CD-R. In this CD-R, 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) are usually used. Is used. Also, two CDs of this form-
A DVD having the structure shown in FIG. 4, in which R is attached with an adhesive or the like.
There is also an optical disc called -R. In this figure, 15 is an adhesive layer. For these types of optical discs, it is desired to recover expensive dye components.

[0005]

Among the optical disk recycling methods proposed so far, there is one in which the disk is crushed and molded as it is. As another method, there is a method in which the disc is immersed in an acid or alkali solution to dissolve the aluminum reflection film, so that the protective film and the substrate are separated and recovered to regenerate the substrate resin. As another method, a method of scraping off the protective film and the reflective film from the optical disc has been proposed. However, the above method has a problem that it is difficult to efficiently collect the dye component.

Therefore, the present inventor has found that the dye layer can be recovered from the disc by bringing the above optical disc into contact with an organic solvent which dissolves the dye layer, and has completed the present invention.

[0007]

A method for recycling an optical disk according to the present invention is a method in which an optical disk comprising at least a substrate, a dye layer, a reflective film and a protective film is brought into contact with an organic solvent which dissolves the dye layer. Characterized by recovering the components. The present invention is a substrate 1 as shown in FIG.
The present invention is not limited to the optical disc composed of 1, the dye layer 12, the reflection film 13, and the protective film 14, and is also applicable to a bonded type optical disc having an adhesive layer 15 as shown in FIG.

In the optical disc 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 disc by scratching the protective film 14 and the reflective film 13. By doing so, the dye component is rapidly dissolved, so that the time required for its recovery can be shortened.

Further, it is desirable to apply an external force to the optical disk during or after contact with the organic solvent, which accelerates the permeation of the organic solvent into the inner layer of the optical disk. Peeling is promoted. As a mode of applying an external force, a method of stirring an organic solvent in which a disc is immersed, or applying ultrasonic vibration to the organic solvent can be adopted.

Further, in the present invention, the solubility parameter (δ value: SOLUBILITY PARAMETER) of the organic solvent is 8 or more and 2
Use 0 or less. When the δ value is within this range, the dye can be dissolved. In particular, when processing an optical disk whose substrate is made of polycarbonate resin, it is desirable to use one having a δ value of 10 or more and 20 or less, as will be apparent from the results of Examples described later. When the δ value is within this range, the dye can be dissolved without dissolving the polycarbonate substrate. If the δ value is less than 8 or more than 20, the dye cannot be dissolved.

Further, in the case of processing a bonded type optical disk having an adhesive layer 15 as shown in FIG. 4 according to the present invention, it is preferable to recover the dye by a method of crushing the disk and then contacting it with an organic solvent.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a disc is brought into contact with an organic solvent (hereinafter sometimes abbreviated as "solvent") which dissolves the dye layer, as it is or after being crushed. In this case, there is no limitation on the state of the disc, 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. Furthermore, a method of bringing a solvent into contact with the dye layer on the substrate after removing the protective film and the reflective film from the substrate, or after removing the protective film, the reflective film and the dye layer from the substrate, the dye layer and the dye layer remain A method of immersing the substrate in a solvent is also preferable. The dye is dissolved and extracted by these methods.

The solvent used is not particularly limited as long as it can dissolve the dye. Further, the solvent is preferably one that does not dissolve the substrate. The reason is that such a solvent facilitates separation of the dye from the substrate and regeneration of the substrate resin.

The substrate is usually made of a polycarbonate resin. Since this resin is soluble 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; 2 A hydroxyketone solvent such as -hydroxy-2-methyl-3-butanone, 4-hydroxy-2-butanone or diacetone alcohol can be used.

Since the dye cannot be dissolved in a hydrocarbon solvent such as hexane (δ value = 7.3) or water (δ value = 21), the object of the present invention cannot be achieved.
However, acetone (δ value = 9.3), toluene (δ value =
The dye can be dissolved / extracted even when a general-purpose solvent such as 8.9), acetonitrile, 2-butanone, or tetrahydrofuran (δ value = 9.1) is used. However, since these solvents penetrate into the polycarbonate resin of the substrate, it is difficult to regenerate the substrate resin.

From the above, in the present invention, an effective solvent for an optical disk whose substrate is made of polycarbonate resin has a δ value of 8 or more, more preferably 10.
The above is 20 or less. Further, in the present invention, a plurality of kinds of solvents having a δ value within the above range can be mixed and used. Further, it is also possible to use a mixed solution 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 in an appropriate ratio. For example, the object of the present invention can be achieved by employing a mixed liquid of ethanol and water at an appropriate mixing ratio. In any case, it suffices that the solvent to be used contains a solvent having a δ value within the above range.

Further, when the disk and the solvent are brought into contact with each other without crushing the disk, the solvent permeates through the protective film, so that it takes time for the solvent to permeate into the dye layer and the extraction of the dye is efficiently performed. Not proceed. In order to avoid this, it is very effective to scratch the protective film side of the disk in advance so that the solvent and the dye layer can come into direct contact with each other. There is no particular limitation on the method of making scratches, and a blade, a heating wire, a laser beam, or the like can be used. There are no particular restrictions on how to scratch, such as the depth, arrangement, and number of scratches, but it is preferable that the scratches start on the protective film side and end on the dye layer (the upper end portion or the lower end portion thereof).

Further, when the disk is immersed in a solvent for extracting the dye, a method of stirring and / or heating the solvent or irradiating the solvent with ultrasonic waves (agitating / heating / irradiating ultrasonic waves of the solvent) is used. It is also possible to use them together), which promotes separation of the substrate and the protective film with a reflective film (separation between the substrate and the reflective film). As a result, the metal material of the reflective film and the substrate resin can be easily recovered.

The peeling between the substrate and the reflection film can be promoted also by rubbing the surface of the dye layer with an appropriate material while the exposed dye layer surface is in contact with the solvent. Specifically, a method of rubbing the surface of the scratched disk with a cloth impregnated with a solvent, or a method of rubbing with a rotating brush while dropping the solvent on the disk surface is employed.

When the peeling between the substrate and the reflection film is promoted by the above-mentioned "rubbing", the material used and its shape are not particularly limited, and examples thereof include metal, plastic, rubber, cloth,
Paper, ceramics, a grindstone, or the like can be used, but these materials are preferably not attacked by the solvent used for peeling. For example, if these materials are dissolved in a solvent, problems such as complicated dye purification process may occur.

In addition to polycarbonate resin, PMMA resin (polymethylmethacrylate), PO resin (polyolefin), epoxy resin, etc. are adopted as the substrate material of the optical disk. In these cases, these are also used as the solvent. It is preferable to employ a resin that does not dissolve the resin but dissolves the dye. Therefore, the type of solvent can be appropriately selected in consideration of the solubility of the dye component and the solubility of the substrate material.

The dye component extracted with a solvent is separated from other components by a method such as filtration, and then purified into a reusable dye component by a physicochemical method. The purification method is not particularly limited, and for example, liquid chromatography can be adopted. Since the dye component is easily decomposed, it is desirable to store the dye solvent solution and perform the dye component purification treatment in a cool and dark place.

[0023]

EXAMPLES Examples of the present invention will be described below. Examples 1 to 5 Write-once discs were used. This disc has a diameter of 12c
m on a polycarbonate substrate for CD-R (compound 1: benzindoline-based perchlorate dye) shown in FIG.
And a quencher (compound 2: nitrophenylamine quencher) in a weight ratio of 1: 1 were dissolved in diacetone alcohol to spin-coat a coating solution (film thickness: about 0.1 μm) With gold film thickness of about 0.1 μm
Was vapor-deposited, and a UV curable resin was spin-coated thereon as a protective film, and this resin layer was cured by irradiation with ultraviolet rays. Thus, this disc has the cross-sectional structure shown in FIG. Using this disc, recording was performed with a CD-R drive manufactured by Sony Corporation, and then the following processing was performed.

Example 1 A disk was cut into a piece of about 2 cm square with a cutter, and this cut piece was dipped in a solvent ethanol and stirred for 30 minutes. As a result, the dye began to dissolve in the solvent, and the cut product separated into the substrate resin and the protective film having the gold film (reflection film) attached thereto. The resin was recovered by removing the substrate resin from the solvent. Further, this solvent was filtered to separate the solid matter, and the dye solution was recovered.

Example 2 As in Example 1, the cut product was immersed in ethanol, and ultrasonic waves were applied to the solvent for 10 minutes. As a result, the dye dissolves in the solvent, the substrate resin, and the protective film with the gold film attached,
Separated into gold dust. Next, the ethanol solution was filtered to separate the above-mentioned three kinds of components, and the dye solution was recovered.

Example 3 A 1 cm square lattice-like scratch was made on the protective film side of the disk with a razor. Next, while spraying ethanol on the protective film side, it was rubbed with absorbent cotton. As a result, the dye was dissolved, and the protective film with the gold film attached was peeled off from the substrate. The ethanol solution was filtered to collect the dye solution.

Example 4 The protective film, the reflective film, the dye layer and a part of the substrate were scraped off from the protective film side of the disk with a razor. When this scraped portion was immersed in ethanol, the dye component was dissolved. This solution was filtered to collect the dye solution.

Example 5 Under the same conditions as in Example 1, the dye recoverability was examined for solvents other than ethanol, and the possibility of dye extraction and the effect on the substrate resin were determined as shown in [Table 1] and [Table 2] below. Summarized in.

[0029]

[Table 1]

[0030]

[Table 2]

The dye extraction solutions obtained in Examples 1 to 5 were evaporated to dryness with an evaporator to obtain a solid containing dye. This solid was separated and purified by a silica gel chromatography method. Elution of each component at this time was performed by gradually adding ethanol to chloroform and adjusting the mixing ratio of chloroform and ethanol (chloroform / ethanol) to 20.
It was carried out by a gradient method in which the solvent polarity was changed gradually from 1/1 to 1/1.

By the above method, the number of recovered compounds is 3
Separated into ingredients. These components were analyzed by proton NMR and FT-IR, and the absorption spectrum was measured by a spectroscope. Next, these results are shown as compounds 1 and 2.
The separated components were identified by comparison with. The results are shown below. Ingredient 1: Aromatic compound (presumed to be a decomposition product of pigment) Ingredient 2: Benzindoline-based perchlorate pigment (Compound 1
Component 3: Nitrophenylamine compound (Quencher of Compound 2) From the above results, it was confirmed that the present invention can recover the dye and the quencher.

[0033]

As described above, according to the present invention, at least an optical disk comprising a substrate, a dye layer, a reflection film, and a protective film is brought into contact with an organic solvent which dissolves the dye layer, thereby increasing the cost. It is possible to recover various pigment components.

Further, in the present invention, the protective film and the reflective film are scratched to accelerate the permeation of the organic solvent into the optical disk, whereby the dye component can be dissolved / extracted in a shorter time.

Further, in the present invention, by applying an external force to the disc during or after the contact between the optical disc and the organic solvent, the peeling between the substrate and the protective film with the reflection film is promoted, so that the recovery of the dye component is further facilitated. It can be done easily.

Further, in the present invention, by using an organic solvent having a solubility parameter of 10 or more and 20 or less, the dye component can be recovered by dissolution / extraction without dissolving the polycarbonate resin as the substrate material. .

[Brief description of drawings]

FIG. 1 is a chemical formula of a dye (compound 1) constituting a dye layer of CD-R according to an example of the invention.

FIG. 2 is a chemical formula of a quencher (compound 2) constituting the dye layer.

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

FIG. 4 is a sectional view showing the structure of a conventional DVD-R.

[Explanation of symbols]

11 ... Substrate, 12 ... Dye layer, 13 ... Reflective film, 14
...... Protective film, 15 ... Adhesive layer.

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP 10-249103 (JP, A) JP 9-193156 (JP, A) JP 6-306200 (JP, A) US Patent 5306349 (US , A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B29B 17/00 G11B 7/26 C08J 11/06 B09B 3/00 B01D 11/02

Claims (4)

(57) [Claims] 1. A method of recycling an optical disk, comprising recovering a dye component by bringing an optical disk comprising at least a substrate, a dye layer, a reflective film, and a protective film into contact with an organic solvent that dissolves the dye layer. 2. The method for recycling an optical disk according to claim 1, wherein at least the protective film and the reflective film are scratched to accelerate penetration of the organic solvent into the optical disk. 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 the separation between the substrate and the protective film with a reflective film. Recycling method. 4. When the substrate is made of polycarbonate resin, a solvent having a solubility parameter of 10 or more and 20 or less is used as the organic solvent.
The method for recycling optical discs according to.