JP2615277B2 - Method for recovering polycarbonate resin for manufacturing optical discs from waste 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 recovering high-quality polycarbonate resin by treating the waste of optical disks, particularly compact disks formed of polycarbonate resin.

[0002]

2. Description of the Related Art A compact disc (hereinafter sometimes simply referred to as a CD) is formed by forming an aluminum reflective film on a polycarbonate signal substrate by vapor deposition or other film forming methods, and then applying a protective coating and printing. Manufactured. It is not desirable to discard such CDs when they are scratched or when disposing of inventories, so a method of destroying and reclaiming or incineration is adopted. However, incineration requires an incinerator with a special structure, and not only requires processing equipment for destruction and landfilling, but also has the problem of selecting landfill sites.
The cost of processing is high and the problem of environmental pollution cannot be ignored.

[0003] Since the amount of these CD wastes is expected to increase more and more in the future, if valuable resources can be recovered from these wastes, it is necessary to reduce processing costs and further reduce CD manufacturing costs. Can also be expected. As a means of collecting such valuable materials, there is a method of mechanically shaving the surface of a CD by, for example, a wire brush method or a sand blast method. However, this method has a problem that wire dust and shot powder cannot be mixed. is there.

Therefore, on the premise of the presence of these contaminants, a method has been proposed in which a CD is crushed as it is and then mixed with a pigment such as carbon black to regenerate the pellet. However, the black pellets thus obtained have disadvantages of insufficient physical properties and limited use.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a conventional CD.
An object of the present invention is to provide a method for treating waste CD, which can improve the drawbacks of the method for recycling CD and efficiently recover a high-quality polycarbonate resin that can be reused as a raw material for CD production. .

[0006]

SUMMARY OF THE INVENTION The object of the present invention as described above is to reduce the waste of an optical disc having an aluminum reflective film on a polycarbonate signal substrate by 3 to 10 m.
and crushed to m, by contacting under stirring with an aqueous treatment liquid and 75 to 100 ° C. containing caustic 10-30%, deposit dissolved or is peeled off, then after the solids were separated from the process solution washed with water and dried, polycarbonate resins for optical disks manufactured from the waste optical disks and recovering the granular polycarbonate resin
Can be achieved by a method of recovering

In the processing method of the present invention, the waste CD must be crushed in advance to have a particle size of 3 to 10 mm. Finer crushing not only causes a problem of dust generation but also lowers the efficiency of water washing and drying treatments, and the quality of collected granular materials is liable to deteriorate. On the other hand, if the particle size is too coarse, there is a problem that removal of the reflective film and the protective paint tends to be insufficient.

As the caustic alkali used in the treatment method of the present invention, sodium hydroxide is preferable, but other caustic alkalis such as potassium hydroxide may be used. When the aqueous treatment solution containing caustic is an aqueous solution of sodium hydroxide, the concentration of sodium hydroxide is 2%.
Desirably, it is about 0%. If the concentration of the caustic is too low, it takes a long processing time to be inefficient, and if it is too high, it is not only difficult to handle but also economical.

The processing temperature in the present invention is 75 to 100 ° C.
However, the temperature is more preferably 80 to 98 ° C. When the processing temperature is too low, it takes time to process and it is not efficient,
There is no particular advantage even when the temperature is 100 ° C. or higher.

[0010]

When the crushed polycarbonate is brought into contact with the aqueous treatment liquid under the above conditions, the aluminum reflection film and the protective coating film are dissolved in the aqueous treatment liquid, and the printed film and the like are peeled off and removed. Therefore, the crushed polycarbonate separated from the aqueous treatment liquid is cleaned by washing with water and recovered as a highly pure granular polycarbonate resin.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The waste optical disc processing method of the present invention will be further described below with reference to embodiments. [Example 1] The waste CD collected from the market was crushed and
A crushed product of about 10 to 10 mm was obtained. 2 kg of this crushed material is heated at a temperature of 9
Put into 20L of 20% aqueous sodium hydroxide solution at 5 ° C,
The stirring was continued for 20 minutes while heating so as not to fall below 80 ° C. Thereafter, when the crushed material was separated from the liquid and washed with water, the aluminum reflecting film, the protective film, the printed film, and the like were all dissolved and removed, and the granular polycarbonate resin containing no impurities was recovered.

Example 2 20 L of a 20% aqueous sodium hydroxide solution was placed in a Henschel mixer having a capacity of 30 L.
After heating to about 90 ° C., 2 kg of waste CD was charged, and the rotary blades were rotated at 600 rpm for 5 minutes while keeping the liquid temperature at 80 to 95 ° C. to coarsely pulverize. Subsequently, the number of rotations is set to 1600 to 1
The milling and processing were continued at 80-95 ° C for an additional 15 minutes at 800 rpm. Thereafter, the processed material is transferred to a sieving apparatus to separate the processing liquid, washed with water and dried, and the particle size is 3 to
mm of recycled polycarbonate resin was obtained.

[0013]

According to the waste optical disk processing method of the present invention, a high-quality recycled polycarbonate resin can be efficiently recovered from a waste CD, and the economic effect is large.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C08L 69:00

Claims (1)

(57) [Claims] 1. An optical disc having an aluminum reflective film provided on a polycarbonate signal substrate is discarded.
And crushed to to 10 mm, by contacting under stirring with an aqueous treatment liquid and 75 to 100 ° C containing caustic 10-30%, is dissolved or peeled off deposits, then solid
It objects to be washed after separating dry from the process solution, polycarbonate for optical disks manufactured from the waste optical disks and recovering the granular polycarbonate resin
A method of recovering the resin .