JP2003305724A - Method for treating resin surface - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treatment method for removing deposit from a resin having the deposit on its surface, and also to provide a treatment method for effectively separating and recovering a solvent used for removing the deposit so as to reutilize the same. <P>SOLUTION: The solvent and the resin are charged in upper and lower rotary mortars at the same time; and, after the mixture of the resin and the solvent is separated and recovered, the solvent is recovered by distillation to peel the deposit on the surface of the resin surface by distilling and recovering the solvent. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing method or a resin surface processing apparatus for removing deposits on the surface of a resin used for a television receiver, a housing of a monitor of a computer or the like. is there.

[0002]

2. Description of the Related Art Plastic has many advantages such as light weight, toughness, good transparency, impermeable to water and gas, easy coloring and molding, and its versatility expands its use year by year. The amount and usage are increasing.
However, along with this, the amount of plastics discarded is also increasing, and the deterioration of the global environment and the shortage of landfill sites have become social problems.

In order to solve these problems and effectively use limited resources, plastic recycling methods have been actively studied in recent years. On the other hand, the Specified Household Appliance Recycling Law (Home Appliance Recycling Law) came into effect from April 2001, and the collection and recycling of waste home appliances will become mandatory, making recycling of plastics an even more important issue. Has become.

As a method of recycling plastics,
Material recycling that recycles used plastics as raw materials for new molded products, thermal recycling that burns and recovers heat, pyrolyzes and uses as a blast furnace reducing agent, or decomposes into oil and monomers and recycles as plastics raw materials. There is chemical recycling to use. Among them, material recycling is the most suitable method, but in recycling as plastic,
If the deposits on the surface of the plastic are mixed, the physical properties of the recycled plastic deteriorate. Therefore, in material recycling, the technique of peeling off the deposits on the surface of the collected plastic becomes important.

The adhered substance has a composition different from that of the resin, and indicates a coating film for making up the surface, oil, lint, blood, body fluid, soil and the like.

Conventionally, in order to peel off plastic deposits, the product is entirely immersed in a solvent that dissolves the deposits and peeled off, or the resin is crushed and mixed with steel balls, and the crushed pieces are rubbed together. There was a method to scrape off the surface. In addition, there is a method in which high-pressure water (water jet) is sprayed on the resin surface to remove the deposits on the surface. The peeling of the coating by the conventional mechanical method will be described with reference to FIG.

As shown in FIG. 4, two discs 7 provided with protrusions 8 are opposed to each other so that the protrusions 8 do not interfere with each other even when the discs 7 rotate. The role of rotating the disk 7 is
The shaft 9. When a flat crushed piece 1 is put in, a protrusion 8 is formed.
The coating on the surface can be peeled off by passing through the gap between them.

[0008]

In recent years, there has been a strong demand for reuse of resources, and treatment of discarded resin and establishment of a reuse method have become important issues.

In the case of removing the deposits on the resin surface in the state of the product, a large device is required in a large shape such as an exterior casing of a television. Further, if the shape becomes complicated, there will be some places where the peeling process cannot be completed. In the case of the method of crushing resin and mixing it with steel balls and rubbing the crushed pieces to scrape off the adhered substances on the surface, if the entire product is scraped off, the resin surface will be scraped off even the unpainted part, so the resin recovered Yield will be poor. Further, according to the example shown in FIG. 4, the surfaces can be scraped off by bringing the resins into contact with each other. Therefore, the crushed resin has a surface only of the resin and a state including the coating film. Are in a mixed state.

Since the resin having no coating film and the deposit containing the coating film are mixed, only the resin not containing the coating film is recovered from the mixture, and the resin containing the coating film is separated and removed. It is difficult and may not be separated as it is. Further, since the whole product is treated, it takes a lot of man-hours to scrape off the part other than the coated surface and the resin on the part other than the coated surface is crushed, so that the recovery efficiency decreases. In this method, for the input resin,
Approximately 20% becomes powder and cannot be distinguished from the one containing the coating film, so it must be discarded. Therefore, the recovery rate is 8
You can expect only 0%.

It is an object of the present invention to provide a method for removing deposits and a device therefor, which can make the device as small as possible and improve the yield of recovered resin.

[0012]

SUMMARY OF THE INVENTION A first aspect of the present invention is to remove resin deposits on the surface of the resin by mixing the resin with deposits on the surface together with a liquid and finely pulverizing with a die. This is a processing method that can In addition, the mortar described in the present invention has an uneven surface for the purpose of crushing, and has a mechanism in which one or both are fixed and the other rotates, and a gap is secured between the two. However, it means that the material to be crushed can pass through the gap.

The direction of rotation of the mortar can be either horizontal or vertical, and the shape of the mortar body is a disk-like outer shape with a groove provided in the portion to be lapped, but the cross-sectional structure of the mortar body is Not specified.

A second aspect of the present invention is the treatment method according to the first aspect of the present invention, which uses, as an example of the liquid, a solvent that dissolves deposits but does not dissolve resin.

A third invention relates to a resin surface treatment apparatus for realizing the above-mentioned first invention.

A fourth invention is characterized in that, in the third invention, the surface of the mortar has a brush shape as an example of the mortar.

A fifth aspect of the invention is a processing method according to the third aspect of the invention, in which the interval (clearance) between the lower die and the upper die is widened to some extent.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a treatment method for separating and removing deposits from a resin whose surface is covered with deposits.

The resin described here is not only the unnecessary plastic material generated in the manufacturing process, the plastic end material, the resin recovered after being used for the housing of home electric appliances, etc., but also becomes defective in the manufacturing process. Also included are items.

The material of the deposit is mainly acrylic or urethane. Some resins include additives such as stabilizers, colorants, flow modifiers, release agents, and coating films in addition to brominated flame retardants and antimony trioxide, but there is no particular limitation. .

The resin can be applied to any one,
It is particularly effective for styrene polymers. Examples of the styrene-based polymer include polymers made of polystyrene, poly-methylstyrene, styrene-butadiene, styrene-acrylonitrile, styrene-butadiene-acrylonitrile, styrene-maleic anhydride, high-impact impact polystyrene and the like.

The above styrene-based polymers may be used alone or as a mixture of two or more. Also, a mixture with another polymer may be used. Further, with respect to the solvent used in the present invention, it is possible to reuse the solvent after separating it into a deposit component and a solvent by a distillation operation.

As described above, according to the present invention, since the adhered substances can be removed from the surface of the recovered waste resin, it is possible to carry out an appropriate treatment, a recycling treatment, and an environment-friendly treatment such as the use of a solvent can be reduced.

Specific examples of the treatment for removing the deposits from the resin having the deposits on the surface according to the present invention will be shown below.

(Embodiment 1) In the present embodiment, a resin having an adhering substance on the surface is crushed in advance into chips having a size of about 2 mm to 3 mm to obtain substantially flat crushed pieces 1. In FIG. 1, this flat plate-like crushed piece 1 is put into a state in which upper and lower dies that rotate together with a liquid are integrated. At this time, since the thickness of the crushed material was about 2.5 mm, the clearance between the upper and lower dies and the clearance = L should be about 95% or less. The flat crushed piece 1 is scraped off by the rotating upper and lower dies 2 and 3 in the process of being ground to 1 mm or less and crushed.

At this time, 96% of the thickness of the crushed material
In the above case, it is preferable that the coating film content is 95% or less because some coating films are not removed. Further, if it is less than 60%, the recovery rate of the resin material is greatly reduced, so 70% or more is preferable.

In the method of removing the coating on the surface of the flat crushed piece 1 with a mortar, a resin surface treating apparatus in which a vertical upper mortar and a lower mortar are integrally formed as shown in FIG. 2 and FIG. Conceivable. That is, in a die in which one is rotated and the other is fixed without being rotated, a gap is secured and the flat crushed piece 1 is passed between them to scrape off the coating on the surface and peel it off. By this method, the coating film on the coated surface is positively scraped off by a die.

In the present embodiment, the mortar has been described as the crushing means, but the crushing means is not limited to this. Further, the same effect is obtained not only when one is rotated but also when both are rotated.

(Embodiment 2) In the case of mixing with a liquid, a solvent is selectively dissolved as a liquid by selectively dissolving the deposit and not dissolving the resin, so that only the deposit is melted positively. Therefore, the adhered material can be more efficiently peeled off without shaving the resin so much.

(Embodiment 3) In the case of mixing with a liquid, the amount of resin crushed can be controlled by making the surface of the die of the apparatus for treating the resin surface into a brush shape. Since the brush shape is slippery with respect to the resin and has the function of actively scraping off adhered materials,
Material recovery efficiency can be improved.

(Embodiment 4) In the case of mixing with a liquid, when a hard resin was simply crushed by a metal mortar provided with grooves, the resin slipped on the surface of the mortar and the crushing ability was lowered. With a die having a diameter of about 250 mm, the limit was 30 kg per hour.

In the resin surface treating apparatus of the present embodiment, the resin was prevented from slipping on the surface of the die by subjecting the surface of the metal die to the electrodeposition of diamond. As a result, the abrasion resistance of the die itself was improved, and it was possible to efficiently scrape off relatively hard resin without slipping due to the hard diamond electrodeposition surface. It was possible to crush 60 kg of hard resin per hour with a die to which hard diamond having a diameter of about 250 mm was electrodeposited.

(Embodiment 5) In the present embodiment, in the apparatus for treating resin surface, the liquid and the resin are put into a rotating die together to remove the adhered matter from the surface of the resin, and then the adhered matter and the liquid are removed. The mixture of (1) is separated into two kinds, that is, a deposit and a liquid, by centrifugation or a sieve. When a liquid that dissolves the deposits, that is, a solvent is used, it is possible to further separate the deposits and the solvent by distilling the present solvent.

As a result, the solvent can be reused, so that the amount of the solvent used to peel off the resin deposit can be reduced.

[0035]

As described above, by using the treatment method of the present invention, the resin having an adhered substance on the surface which is expected to be discarded and becomes a problem in the future is separated and removed, and only the resin is supplied. You can do it. Further, by reusing the resin recovered in this way, it is possible to reduce waste and also reuse the solvent used for removing the deposits, which helps to solve the environmental problem.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a rotation center injection horizontal die which is a resin surface treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a peripheral-charging vertical die which is a resin surface treatment device according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view of a rotation center charging vertical die that is a resin surface treatment device according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view of a blade of a resin surface treating apparatus in a conventional example.

[Explanation of symbols]

1 Flat crushed pieces 2 mortar 3 lower mill 4 Center fixing bolt 5 Upper mill 6 Lower mill 7 discs 8 protrusions 9 shaft

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08J 3/12 CEZ C08J 3/12 CEZ // C08L 101: 00 C08L 101: 00 (72) Inventor Keizo Nakajima Matsuda Denki Sangyo Co., Ltd. 1006 Kadoma, Kadoma City, Osaka Prefecture (72) Inventor Takao Kusumi In-house F-term (Reference) 3B116 AA48 AB01 BA01 BA02 4D063 DD06 DD14 GA10 GC35 4F070 AA71 DA42 DA48 DA50 DB09 4F301 AA15 AB03 BD05 BF02 BF12 BF32 CA09 CA32 CA68

Claims (5)

[Claims] 1. A method for treating a resin surface, comprising: a step of crushing a resin having an adhered substance on the surface; and a step of crushing the crushed resin while adding a liquid. 2. The method for treating a resin surface according to claim 1, wherein the liquid is a single solvent or a plurality of solvents that do not dissolve the resin. 3. A resin surface treating apparatus characterized in that a resin having an adhered substance on the surface is crushed by a plurality of dies while adding a liquid to separate the adhered substance from the resin. 4. The resin surface treatment apparatus according to claim 3, wherein the surface of the die is brush-shaped. 5. The resin surface treatment apparatus according to claim 3, wherein the clearance of the plurality of dies is 95% or less of the thickness of the resin.