JPS60223835A - Recovery of base material and magnetic powder from magnetic recording medium - Google Patents

Abstract

PURPOSE:To separate and recover easily and efficiently both of a magnetic powder and a base material each in a pure form, by immersing a magnetic recording medium in a solution of a basic substance and a surfactant in a specified concentration and agitating the formed mixture. CONSTITUTION:A magnetic recording medium formed by coating a synthetic resin base material such as polyethylene terephthalate with a magnetic material (e. g., ferrite powder) with the aid of an organic binder based on urea resin or the like is cut into fine chips. These chips are immersed in a solution (5-100 deg.C) of a mixture of 0.1-20wt% basic substance (e.g., NaOH) and 0.01-5wt% surfactant (e.g., a 1:1 sodium oleate/dodecylbenzenesulfonic acid mixture) and agitated to precipitate peeled and pulverized magnetic substance powders within a short time and float the organic binder on the surface by adsorption on bubbles. The bubble layer is separated and removed and the remaining liquid is treated by filtration, centrifugation, or a like operation to separate the base material from the magnetic substance powder, which are then washed, dried, and recovered.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a method for recovering base material and magnetic powder from magnetic recording materials, and in particular, a method for recovering base material and magnetic powder from scrap magnetic recording materials. This invention relates to a method for easily recovering the product.

[Technical background of the invention 7 and its problems J In recent years, with the rapid development of the information industry, magnetic recording materials such as magnetic recording tapes such as A-dio recording tapes, computer tapes, and video tapes, magnetic cards, and floppy disks have become increasingly popular. Natsu Cki-C is used for people.

As a result, a large amount of scrap magnetic recording materials are being generated in various places as rejected products in the manufacturing process or used products at the general consumer stage, but currently they are being disposed of by methods such as landfilling and incineration. It has been discarded, and it is hoped that it will be used effectively from the perspective of resource reuse.

Conventionally, methods for recovering magnetic powder from waste magnetic recording materials have been studied, but they have not yet been put to practical use.

In other words, there are many types of magnetic recording materials, including the type and content of the magnetic material, the type and content of the organic binder, the type and content of plasticizers, stabilizers, lubricants, and other additives. The ease with which the magnetic powder can be peeled off from the base material varies depending on the coating method, laminated composition, etc., and a recovery method that can be applied to all of them is not yet known.

However, these materials are mixed in the magnetic recording materials of C waste, and therefore, in order to recover the base material and magnetic powder from the magnetic recording materials of deceased items, it is necessary to dispose of them using a processing method that can be applied to any type of waste. If so, it cannot be said to be practical.

In particular, in recent years, as there has been a demand for more advanced performance such as improved wear resistance, many magnetic recording materials have appeared whose magnetic powder layers do not peel off easily, making it difficult to recover the base material and magnetic powder. Natsu C is here.

For example, as a conventional technique, a method is known in which waste magnetic recording material is immersed in an alkaline aqueous solution to separate it into the base material and magnetic powder. It only swelled, and it was impossible to completely peel it off from the base and collect the base material and magnetic powder purely.

In addition, there is a large amount of @ in the magnetic powder separated by this method.
Since the machine binder is mixed, it takes many steps to separate it.
There was also the problem that it required a large number of people.

Even if the base material and magnetic powder can be recovered from this magnetic recording material, impurities tend to remain in the recovered material, and it cannot be used as is for its original purpose such as a molding material or magnetic material. This would reduce their utility value.

[Object of the invention] The present invention has been made in response to such conventional circumstances,
The present invention aims to provide a method that can be applied to all kinds of magnetic recording materials and that can separate and recover base IJ Fl and magnetic powder as pure products with high utility value from their waste products.

[Summary of the Invention] That is, the method of recovering the base material and magnetic powder from the magnetic recording material of the present invention is to collect the base material from the magnetic recording material obtained by coating the base material with the magnetic powder using an organic binder. In collecting the magnetic powder, the magnetic recording material is immersed in a mixed solution containing 0.1 to 20% by weight of an i-based substance and 0.01 to 5% by weight of a surfactant, and stirred. It is characterized by

Magnetic recording materials to which the present invention can be applied include magnetic recording tapes such as audio recording tapes, computer tapes, and video tapes, magnetic cards, floppy disks, etc.
All C magnetic recording materials are included.

That is, the magnetic recording material consists of a base material that serves as a support, and
It consists of magnetic powder layered on this base material, an organic binder, a plasticizer, a stabilizer, a swelling agent, and other additives that bind these base materials and the magnetic powder. , its type and content, coating method, laminated composition, etc. are not limited in any way.

The base material for such magnetic recording monthly rate is
Examples include polyesters such as polyethylene terephthalate, polypropylene, polyethylene, and polyvinyl chloride.

Examples of the magnetic powder include iron oxide, l1IitA, ferrite, cobalt alloy, and chromium oxide.

Furthermore, organic binders include urea resin, melamine resin, amino resin such as guanamine, polyester resin, epoxy resin, acrylic resin, melamine resin,
Examples include organic binders based on thermosetting resins and thermoplastic resins such as polyurethane resins, aromatic hydrocarbon resins, silicone resins, and vinyl chloride-vinyl acetate copolymers.

Examples of basic substances used in the mixed solution used in the present invention include substances that exhibit alkalinity in aqueous solutions, such as hydroxides, oxides, carbonates, and tertiary amines of alkali metals and alkaline earth metals. be.

Specific examples include caustic acid, caustic potash, soda carbonate, pyridine, and triethanolamine.

The surfactant may be anionic, cationic, nonionic, or zwitterionic, and general-purpose surfactants such as α-olefin, higher alcohol, fatty acid, and sulfonic acid surfactants may be used. Can be used.

These basic substances and surfactants are used alone or in combination of two or more at °C.

The temperature of the basic substance in the mixed solution is 0.1 to 20% by weight.
is preferred, and a range of 0.5 to 10% by weight is particularly suitable. If the concentration of the basic substance is less than 0.1% by weight, the peeling rate will be low, which is disadvantageous in practice, and if it exceeds 20% by weight, the molecular weight of the paste material may decrease, which is undesirable.

The concentration of the surfactant in the mixed solution is preferably from 0.01 to 5% by weight, particularly preferably from 0.05 to 2% by weight. If the surfactant content is 0.01%, the peeling speed will be low (this is disadvantageous in practice; on the other hand, if it exceeds 5% ω%, foaming will increase and should be recovered). This is undesirable because the transfer of the paste material and magnetic powder to the foam layer increases.

The temperature of the mixed solution used is preferably 5 to 100°C. 5
If the temperature is less than 100°C, the rate of peeling will be low, whereas if it exceeds 100°C, the paste material and magnetic powder will be thermally degraded, and it will be dangerous to work, which is not preferable.

Magnetic recording materials are cut into strips in advance, immersed in a mixed solution containing a basic substance and a surfactant as described above, and then stirred. The magnetic powder layer is peeled off from the paste material and atomized in a short time without stirring. In addition, other fixing agents, plasticizers, etc. migrate to the foam layer above the processing solution and are easily separated.

In the present invention, the peeled magnetic powder is separated as the magnetic powder settles while the organic binder is adsorbed by bubbles formed by the surfactant and floats to the surface. The amount of the mixed solution relative to the magnetic recording material is not limited, as long as the processing solution can be easily stirred into the processing material.

Although the processing time can be freely changed depending on the type and shape of the magnetic recording material, basic substance concentration, surfactant concentration, and processing temperature, it is important to ensure effective peeling and minimize the decrease in the molecular weight of the base. It is important to take the time.

After the stirring process is completed, the foam layer at the top of the processing solution to which the fixing agent and other additives have been transferred is separated and removed. The remaining liquid from which the foam layer has been removed is treated by a filtration method, a separation method based on a difference in specific gravity, etc., and is separated into a base material and a magnetic powder. The separated ICC paste material and magnetic powder are washed and dried, respectively, and the obtained paste material and magnetic powder can be reused as magnetic recording materials or similar applications.

[Embodiments of the invention] Examples of the present invention will be described below.

Example: A commercially available videotape whose base is polyethylene terephthalate and whose magnetic material is ferrite and whose weight ratio is 44°9+55.1 is about 5 CIllf! ! i! The sample was cut into a piece of tape with a length of 100 degrees.

This test IJ10o was mixed with 5% by weight of caustic soda and 2
It was added to 100 cc of a mixed aqueous solution at 80° C. containing % by weight of a surfactant (for example, a 1:1 blend of Δ sodium oleate and dodecylbenzenesulfonic acid), and stirred for 10 minutes using a stirrer (peripheral speed 40 m/s).

Bubbles were formed on the liquid surface at the same time as the stirring, and as the stirring time elapsed, the separated organic binder was captured in the foam layer.

After that, separate the workpiece and take out the tape piece from the processing solution 3
After washing with water twice and drying, polyethylene terephthalate 4.04a free of any other adhesion of magnetic powder was collected. The remaining liquid was allowed to settle by gravity, and the settled magnetic powder was washed with water three times and dried, resulting in a purity of 99.9%.
4.96q of the above ferrite powder was collected.

Separately, as a comparative example, polyethylene terephthalate and ferrite were separated by treatment under the same conditions as in Example 1 except that no surfactant was used. In this comparative example, a large amount of residual deposits remained on the base material even after 10 minutes of treatment, and even after continued stirring for an additional 30 minutes, the presence of residual deposits on the base material was observed.

In addition, many organic binder contaminants were found in the magnetic powder separated by washing with water three times, and C
However, it was not possible to completely eliminate the organic binder.

[Effects of the Invention] As explained above, according to the method of the present invention, it is possible to easily and efficiently recover pure base material and magnetic powder from any kind of magnetic recording material. Therefore,
The recovered base material and magnetic powder can be used as raw materials for their original high value-added applications.

Representative Patent Attorney Su Yamasa -

Claims (6)

[Claims] (1) In recovering the base monthly yield and magnetic powder from a magnetic recording material formed by coating magnetic powder on a base material with an organic binder, the magnetic recording material is coated with 0.
A base material and magnetic powder are recovered from a magnetic recording material characterized by immersion in a mixed solution containing 1 to 20% by weight of a basic substance and 0.01 to 5% by weight of a surfactant and stirring. Method. (2) A method for recovering a base material and magnetic powder from a magnetic recording material according to claim 1, wherein the temperature of the liquid mixture is 5 to 100°C. (3) A method for recovering base material a3 and magnetic powder from a magnetic recording material according to claim 3, wherein the base material is a synthetic resin material. (4) A method for recovering a base material and magnetic powder from a magnetic recording material according to claim 3, wherein the base monthly yield is poly-1-dylene terephthalate. (5) A method for recovering a base material and magnetic powder from a magnetic recording material according to claim 1, wherein the magnetic powder is a ferrite powder. (6) A method for recovering a base material and magnetic powder from a magnetic recording material according to claim 1, wherein the basic substance is caustic soda.