JPS60223836A - Recovery of starting material from scrap film having fine solid particle layer on surface - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for recovering raw materials from film scraps having a fine solid layer formed on the surface thereof, and in particular to scrap magnetic recording materials,
This invention relates to a method for easily recovering pure base films, magnetic powders, etc. from raw materials.

[Technical background of the invention and its problems] In recent years, with the rapid development of the information industry, fine solid particles such as magnetic recording tapes such as audio recording tapes, magnetic cards, and floppy disks have come to be used in large quantities. There is.

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, 2.3 studies have been conducted on methods for recovering magnetic powder from waste magnetic recording materials, but they have not yet been put to practical use.

There are many types of magnetic recording materials, and the types and contents of magnetic materials, types and contents of organic binders, types and contents of plasticizers, stabilizers, lubricants, and other additives, Furthermore, the ease with which the magnetic powder can be peeled off from the C base film 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, waste magnetic recording materials contain a mixture of these materials, and therefore, in order to recover the base film and magnetic powder from waste magnetic recording materials, a processing method that can be applied to any type of waste is required. It's not practical.

In particular, in recent years, due to the 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 film and magnetic powder. It has become.

For example, as a conventional technique, a method is known in which waste magnetic recording material is immersed in a strong alkaline aqueous solution to separate it into a base film and magnetic powder. It only swells, and it is impossible to completely peel it off from the base and collect the base film and magnetic powder purely.
Furthermore, since a strong alkali, which is a powerful chemical, is used, caution is required during work, and there is also the problem that corrosion protection must be applied to the equipment.

Furthermore, since a large amount of organic binder is mixed in the magnetic powder separated by this method, there is also the drawback that separation thereof requires a lot of effort.

For this reason, even if base films and magnetic powders can be recovered from magnetic recording materials, impurities tend to remain in the recovered materials, and they cannot be used as they are for their original purpose such as molding materials or magnetic materials. It was supposed to reduce its utility value.

In addition, films that are generally disposed of as waste are thin, and are often overlapping or bent. Therefore, when agitated in water using a normal cleaning method, fine solid particles can be collected between the overlapping film scraps. It was difficult to completely separate the

[Object of the invention] The present invention has been made in response to such conventional circumstances,
It can be applied to all kinds of film waste with a layer of fine solid matter, and the base film and fine solid matter can be separated and recovered from these waste products as pure products with high utility value, and the recovery method does not require the use of strong alkalis. The purpose is to provide a method.

[Summary of the Invention] In other words, the method for recovering raw materials from film scraps having a fine solid layer formed on the surface of the present invention includes a method for recovering raw materials from film scraps having a fine solid layer formed on a base film. It is characterized in that the scraps are immersed in an aqueous solution containing 0.01 to 5% by weight of a surfactant and stirred using a stirrer equipped with high-speed rotary blades.

Film scraps to which the present invention can be applied include scraps of all magnetic recording materials such as audio A recording tapes, computer tapes, video tapes, magnetic cards, floppy disks, etc., as well as photographic films and masks. Film, conductive film scraps, etc. are included.

This type of film waste consists of a base film that serves as a support, a fine solid material formed on this base film, an organic binder, a plasticizer, and a stabilizer for bonding the base film and the fine solid material. , swelling agents, other additives, etc., but their types and contents, and]
There are no limitations on the coating method, laminated composition, etc.

Examples of the base film of such film waste include polyester such as polyethylene terephthalate, polypropylene, polyethylene, polyvinyl chloride, and the like.

In addition, fine solids include iron oxide, pure iron, ferrite,
Examples include magnetic powder such as cobalt alloy and chromium oxide, as well as silver (photographic film), carbon (mask film), and the like.

Furthermore, organic binders include urea resin, melamine resin, amine 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.

The surfactant used in the aqueous solution used in the present invention may be anionic, cationic, nonionic, or zwitterionic, and may be α-olefin, higher alcohol, fatty acid, or sulfonic acid. A general-purpose surfactant such as a surfactant such as a surfactant can be used.

These surfactants may be used alone or in combination of two or more.

The concentration of surfactant in the mixed solution is 0.01 to 5% by weight.
is preferred, and a range of 0.05 to 3% by weight is particularly suitable. If the blending amount of the surfactant is less than 0.01% by weight, the peeling speed will be low, which is disadvantageous in practice;
If it exceeds % by weight, it is not preferable because foaming becomes intense and the transfer of the base film and magnetic powder to be collected becomes large.

The working temperature of the mixed solution used is preferably 5 to 100°C. Below 5°C, the rate of peeling decreases; on the other hand, below 100°C
Exceeding this is not preferable because the base film and the magnetic powder will be thermally degraded and the work will be dangerous.

Film scraps are cut into strips in advance, immersed in a mixed solution containing a surfactant as described above, and stirred using a stirrer equipped with high-speed stirring blades. C. Due to the shear force and centrifugal force of the high-speed stirring blades, the fine solid layer is peeled off from the base material and atomized in a short time. In addition, other fixing agents, plasticizers, etc.
The treatment solution moves to the upper part of the solution and is easily separated. The rotation speed and size of the rotary blade of the stirrer are 20 to 40I in circumferential speed.
ll/sec, the centrifugal force generated at that time is 150-300k
A material of about g-1/82 is suitable.

An example of an agitator C equipped with such a high-speed rotary blade is a Henschel mixer (trade name, manufactured by Mitsui Miike Kakoki Co., Ltd.). The rotation speed of the Henschel mixer rotor is said to be variable, but normally this rotor is 2011/sec, 40
It is used by switching between two stages of 11/sec (both peripheral speeds).

In the present invention, while the particulate solids exfoliated during the stirring process settle due to centrifugal force, the organic binder is adsorbed by the bubbles formed by the surfactant and floats to the surface and is separated.

The amount of the aqueous solution relative to the film scraps is not limited, as long as there is a rut C that allows the aqueous solution to be easily stirred into the material to be treated.

The stirring time can be freely changed depending on the type and shape of the magnetic recording material, surfactant concentration, and processing temperature, but it is important to select a time that allows for effective peeling and minimizes the decrease in the molecular weight of the base. .

After the stirring process is completed, the upper portion of the processing solution to which the fixing agent and other additives have migrated is separated and removed. The remaining liquid from which the particles have 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 film and fine solid particles. The base film and magnetic powder separated here are washed, dried, and used again for the same or any desired purpose.

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

Example A commercially available videotape waste whose base was made of polyethylene terephthalate and whose magnetic material was made of ferrite and whose weight ratio was 44°9:55.1 was cut into pieces of tape with a length of about 5C11. It was used as a sample. 2 kg of this sample was mixed with 80% by weight of a surfactant containing 2% by weight of a surfactant (for example, a 1:1 combination of sodium oleate and dodecylbenzenesulfonic acid).
Place the mixed aqueous solution at 201 °C in a Henschel mixer and stir for 10 minutes using a YTJ half-machine at a rotation speed of 24.
5Or・pm, centrifugal force 150kg ”III/s2
).

Bubbles were formed on the liquid surface simultaneously with stirring, and as the stirring time elapsed, the peeled organic binder was captured in the foam layer.

Thereafter, the foam layer was separated, and the tape piece was taken out from the treatment solution, washed with water three times, and dried. Polyethylene terephthalate 4.04a was collected without any other adhesion of magnetic powder. 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%.
4.96 u of the above powder was collected.

Separately, as a comparative example, videotape waste was treated with the same strip f1 as in Example 1 except that the C1 surfactant was not used to separate it into polyethylene terephthalate and ferrite. In this comparative example, a large amount of residual deposits remained on the base film even after stirring for 10 minutes, and the presence of residual deposits on the base film was observed even after stirring for an additional 30 minutes.

In addition, a large amount of organic binder was found in the magnetic powder separated by washing with water three times, and the organic binder could not be completely removed even after washing with water five times.

[Effects of the Invention] As explained above, according to the method of the present invention, any type of film waste with a fine solid layer formed on its surface can be removed.
The base film and magnetic powder can be easily and efficiently recovered in a pure state. Therefore, the recovered base film and magnetic powder can be used as raw materials for their original high value-added applications.

Furthermore, the present invention has the advantage that it is safe to work with since no strong alkali is used, and there is no need to provide special anti-corrosion protection to the equipment.

Claims (6)

[Claims] (1) When recovering raw materials from film waste with a fine solid layer formed on the base film, the film waste is immersed in an aqueous solution containing 0.01 to 5% by weight of a surfactant, and A method for recovering raw materials from film waste having a layer of fine solid matter formed on its surface, characterized by stirring using a stirrer equipped with. (2) A method for recovering raw materials from film waste having a fine solid layer formed on the surface thereof according to claim 1, wherein the temperature of the aqueous solution is 5 to 100°C. (3) A method for recovering raw materials from film scraps having a fine solid layer formed on the surface thereof according to claim 3, wherein the base film is a synthetic resin material. (4) A method of recovering raw materials from film waste in which the base film has a layer of solid polyethylene terephthalate particles. (5) A method for recovering raw materials from film waste having a layer of fine solid matter formed on its surface as claimed in claim 1, wherein the fine solid matter is a magnetic powder. (6) The rotation speed of the high-speed rotor blade is 20 to 40 m/s (circumferential speed)
and the centrifugal force formed by this is 150~
300 kg-m/S2. A method for recovering raw materials from film waste having a fine solid layer formed on its surface as claimed in claim 1.