WO2003020486A1

WO2003020486A1 - Method of reprocessing fire-resistant plastics

Info

Publication number: WO2003020486A1
Application number: PCT/JP2002/008891
Authority: WO
Inventors: Toshiaki Miyanaga; Katsuhiro Yamada; Takuji Motegi
Original assignee: Nippon Steel Chemical Co., Ltd.
Priority date: 2001-09-03
Filing date: 2002-09-02
Publication date: 2003-03-13
Also published as: CN1549765A; JPWO2003020486A1; CN100453284C

Abstract

A method of processing fire-resistant plastic molded products used in discarded TV casings or the like to reuse them as recycled fire-resistant plastics. A method of reprocessing fire-resistant plastics comprising the steps of pulverizing fire-resistant plastic molded products recovered from wastes containing fire-resistant plastic molded products, and surface-grinding the obtained pulverized products to scrape off 3-30 wt.% of the surface layer. The surface grinding can employ a dry cleaning process for scraping off the surface layer by allowing pulverized products or pulverized products and container walls to collide to one another. Recycled fire-resistant plastics obtained by this method can be used singly or by being blended with unused fire-resistant plastics similar to or dissimilar from the recycled fire-resistant plastics at a weight ratio of 5-95:95-5, and satisfies a UL standard V-0 or V-2 grade.

Description

Specification

Recycling treatment method for flame-retardant plastic

Technical field

The present invention relates to a method for reclaiming a flame-retardant plastic used for discarded home electric appliances and information devices, and more particularly to material recycling of a flame-retardant plastic molded product. Background art

Home appliances such as televisions and information devices such as personal computers, printers, and copiers generate heat, and from the viewpoint of fire prevention, flame-retardant plastic is used for their cabinets and bodies. Is used. After being used for a long time, the surface properties of the flame-retardant plastic molded products used as these components have deteriorated significantly due to ultraviolet and thermal deterioration, etc., in the original plastic properties. For this reason, the use of flame-retardant plastic molded products recovered from discarded products as a resin is a major obstacle to so-called material recycling.

In addition, the surface layer of a molded product such as a cabinet is not only stained with hand marks or dust, but also has a sticker or the like, is sometimes painted, or is printed such as silk printing. Then, even if you try to reuse used molded products, they become foreign substances and do not exhibit sufficient physical properties. Therefore, as a method of treating used flame-retardant plastic molded products, incineration is used. Processing, thermal decomposition, oiling, and landfilling were the main factors, but flame-retardant plastics often contain halogenated flame retardants as flame retardants, and incineration and oiling are also environmentally friendly. There's a problem. Therefore, Japanese Patent Application Laid-Open No. 12-290424 proposes a method in which a flame-retardant plastic containing a flame retardant is previously brought into contact with water or alcohol to remove the flame retardant, and this is used as a recycled resin. In Japanese Patent Application Laid-Open No. 7-285128, in order to regenerate a plastic molded article with a coating film, a crushing process is combined with a coating film removal process by mechanical, chemical or physical means, and is extruded and regenerated. A method of using a resin is proposed. However, it would be advantageous if used flame-retardant plastics could be recycled as flame-retardant plastics. Disclosure of the invention

An object of the present invention is to make a used flame-retardant plastic molded product recovered and sorted out from discarded home electric appliances and information devices into recycled flame-retardant plastic.

The above issues were collected from household electrical appliances waste, information equipment waste, etc.'The crushed flame-retardant plastic molded product was crushed, and the obtained crushed material was dry-cleaned, and the surface layer of the crushed plastic was 3 ~ Achieved by scraping 30% by weight. Hereinafter, the present invention will be described in detail.

The flame-retardant plastic molded product that is recycled in the present invention (it may be referred to as a flame-retardant molded product) is a fire-retardant molded product that is obtained by manually disassembling or mechanically disassembling household electric appliance waste and information equipment waste. It is. Examples of such a flame-retardant molded article include a casing made of flame-retardant plastic, such as a television cabinet, a personal computer body, a display casing, a printer casing, a copying machine casing, and the like. A part of the body, for example, a member such as a TV back cover is included. Plastic molded products removed from household electrical appliances waste and information equipment waste are divided into flame-retardant plastics and non-flame-retardant plastics, and furthermore, flame-retardant plastics are classified according to the type of plastic, flame retardant grade (V-0 , V-2, etc.). For relatively new products, the resin variety can be distinguished by the symbol engraved on the plastic molded product, and the selection is easy. In addition, information provided by the manufacturer or information that has been handled in the past may be used.

However, plastic molded products that do not have such a resin type can be obtained by the pyrolysis-spectroscopic analysis method described in JP-A-2000-292350, the specific gravity difference sorting, the IR reflection spectroscopy described in the section of the prior art, and the like. And the presence, type, etc. of the flame retardant can be determined. In particular, even when the presence or absence of a halogen-based flame retardant is unknown, when the presence or absence is determined and the resin member is selected from a resin member containing a haptic-based flame retardant and a resin member not containing the halogen-containing flame retardant, X-ray fluorescence analysis is preferable.

Collected by resin type and flame-retardant grade ■ The flame-retardant molded products that have been selected may be attached with stickers, painted, or printed such as silk-screened. Electronic components, wiring, transformers, heaters, etc. are virtually completely removed.

In the regeneration treatment method of the present invention, the flame-retardant molded product is crushed. The size of the crushed material is preferably set to an average diameter of 20 mm or less so that the surface layer in the next step is not easily removed. More preferably, the average diameter is from 1 to 15 rnm, even more preferably from 3 to 1 Omm.

Here, the average diameter means a plane average diameter when the flame-retardant molded product is a plate-like body formed from a molded product such as a cabinet. For this crushing treatment, a commercially available plastic crusher may be used. The power to generate fine powder when pulverized. Since this is mostly generated from the surface layer, it is less than 10 mesh. The powder may be separated.

Next, the crushed material obtained by the crushing treatment is subjected to a surface grinding treatment to scrape off the surface layer. By this surface grinding treatment, it is possible to remove foreign matter and a deteriorated layer present on the surface of the crushed flame-retardant plastic molded product recovered from the waste. The method of shaving off the surface layer is preferably a dry cleaning treatment, that is, the principle of crushing the crushed materials vigorously and abrading and rubbing the surface layer of the crushed material is preferably applied. For example, pulverized material is sent to a wear chamber with high-pressure gas, or pulverized material is sent to a wear chamber that rotates at high speed without using high-pressure gas. Dry cleaning treatment for efficiently and thinly peeling off the surface layer portion may be mentioned. For example, Ein's Engineering Co., Ltd.'s Clean Separator (see Patent Nos. 2,558,807, 2,954,093, and 3,048,283) and Himont's (See Patent No. 3277932), which are compact and easy to operate, and are preferred as dry-cleaning treatment equipment.

Here, the device described in the above-mentioned Patent No. 25553807, etc., crushes a crushed resin molded product having a resin coating film formed on the surface by applying a compressive impact force based on microvibration. This is a device provided with means for peeling off the resin coating film and separating the peeled coating film. Further, the apparatus described in the above-mentioned Patent No. 32797332 is used to finely pulverize a crushed resin molded product having a varnish coating on its surface, and at the same time, generate an elongational force and a shearing force on the particles to be ground. is, thereby to peel the Wa two scan attached, either a _c these devices a device provided with means for separating exfoliated Waesu particles, by utilizing the fact that the physical properties of the coating film and the resin is different from the coating Although it is a device for selectively separating a film, it has been found that by using such a device, it is possible to selectively separate a resin surface layer of a flame-retardant resin other than a coating film. This is because the surface layer deteriorates greatly and the physical properties with the inner layer and fracture surface It is considered that the above is different, and any device utilizing such a phenomenon can be advantageously used.

Although wet treatment using high-pressure water instead of high-pressure gas is also possible, wastewater treatment is required and its practicality is low. In addition, although not simple, there are, for example, a method of applying high vibration to the pulverized material to forcibly peel off the surface layer, and a method of chemically eluting and removing the surface layer by solvent treatment. These methods can be appropriately selected according to the type of plastic and the use of the recycled product. Dry cleaning treatment does not use heat, so it is possible to save energy. In the present invention, the surface layer of the crushed material may be scraped off until substantially no foreign matter or degraded layer is present, but it is 3 to 30% by weight of the crushed material before the treatment, preferably 5 to 5%. It is good to remove 25% by weight, more preferably 7 to 20% by weight. If the content is less than 3% by weight, foreign matter and a deteriorated layer may remain. If the content is more than 30% by weight, waste is increased and material recycling efficiency is reduced.

Also, the shaving amount is preferably changed depending on the thickness of the crushed material. When the average thickness is 2 mm or more, the amount is preferably 3 to 15% by weight, and when the average thickness is less than 2 mm, 15 to 30% by weight is preferred. The average thickness to be scraped is 0.1 to 1.0 mm, preferably 0.2 to 0.6 mm.

Here, the shaving rate of the surface layer is determined by the weight A of the crushed material subjected to the surface grinding treatment, and the amount of the powder passing through the 20 mesh when the surface grinding treatment is performed and sieved into 20 meshes. When B is represented, it is represented by B / AX100, and this value is preferably 3 to 30% by weight. In this case, it is preferable that the crushed material to be supplied does not include powder that passes through 20 mesh. If powder is included, add 1

And B are not included in the calculation.

The average thickness to be scraped is expressed as C--D when the average thickness C of the crushed material subjected to the surface grinding treatment and the average thickness D of the crushed material that does not pass through the 20 mesh after the surface grinding treatment are expressed as follows: This value is preferably between 0.1 and 1.0 mm.

In this way, by grinding the crushed material, the surface foreign matter may be covered with dust, dust, etc., painted, taped or sealed, or paper adhered as foreign matter on the surface. Even if it is printed, printed, or has adhesives or the like, there is no problem at all, and it is possible to obtain the most suitable recycled flame-retardant plastic by shaving off the surface.

By this surface grinding process, in addition to the foreign matter and the deteriorated layer, a layer such as a coating film and a coating is removed, and a part of a non-deteriorated layer such as a fracture surface layer generated by the crushing process becomes powder. The surface grinding conditions are selected so that the non-deteriorated layer does not occupy most of the powder generated by the surface grinding.

The crushed flame-retardant plastic that has been surface-ground in this way may have powder generated by surface grinding or dust (dust) adhering due to static electricity or the like. In order to remove these fine powders, a wind-cleaning treatment is used to blow off the fine powders using a wind-cleaning machine, or a wet-cleaning treatment is used to remove the fine powders using a cleaning liquid such as water that does not dissolve the treated plastic. A more preferable recycled flame-retardant plastic can be obtained.

When the recycled flame-retardant plastic thus obtained is subjected to kneading treatment to form a recycled pellet, the deterioration in quality due to the surface deterioration layer is somewhat absorbed by this kneading treatment. Therefore, it is possible to further relax the surface grinding conditions in the preceding stage in consideration of the absorption of quality deterioration due to the use of the recycled pellet. In other words, taking into account the absorption of the quality deterioration of the surface-deteriorated layer by the kneading process (regeneration pelletizing), the main purpose of the surface grinding in the first stage is to remove foreign substances,

In some cases, it may be sufficient to remove only ~ 5% by weight. Such recycled flame retardant plus Ticks exhibit the same level of flame retardancy as unused flame-retardant plastics, but have slightly worse mechanical properties than unused flame-retardant plastics. Therefore, in applications where the required level of mechanical strength is low, this recycled flame-retardant plastic can be reused as it is as a raw material for molding, but the recycled flame-retardant plastic is used for discarded products. When used in the same cabinet or the like, it is advisable to mix the same or different unused flame-retardant plastics (paigne) in order to increase the strength. In this case, the preferred blending ratio of the recycled flame-retardant plastic and the unused flame-retardant plastic of the same type or different from the recycled flame-retardant plastic is 5 to 95: 95 to 5, more preferably 1 to 5. The weight ratio is 0 to 50: 90 to 50, more preferably 20 to 40: 80 to 60. Usually, less than 50% by weight of recycled flame-retardant plastic

Recycled flame-retardant plastics obtained by mixing at 0% by weight or more (also called modified recycled flame-retardant plastics) can exhibit the same level of flame retardancy and mechanical properties as 100% virgin . When blending different kinds of unused flame-retardant plastics, a combination giving good physical properties is adopted, and such a combination is known.

If the content of the recycled flame-retardant plastic in the modified recycled flame-retardant plastic is large, physical properties such as MFR (flowability), IZ impact strength and elongation at break are inferior, but tensile yield strength, tensile break strength, Flexural strength and flexural modulus are on par with virgin regardless of the mixing ratio.

The mixing method is not particularly limited, and examples thereof include a method in which recycled flame-retardant plastic pellets and virgin pellets are mixed at a predetermined ratio, and heated and melted by an extruder or the like to repellet. Can be If only recycled flame-retardant plastic pellets are used, they can be made into pellets as well. No.

The base resin of the flame-retardant plastic in the present invention is not particularly limited. For example, polystyrene represented by HIPS and GPPS, acrylonitrile-butadiene-styrene copolymer resin (ABS), polyp Examples include propylene, polyethylene, and polyvinyl chloride, and a polymer alloy or a polymer blend of these may be used. In particular, styrene resins, HIPS, GPPS, AS, ABS, and MBS, are often used alone or in combination as base resins for flame-retardant plastics used in home appliances. It is suitable for the material recycling of the invention. Particularly, it is suitable for HIPS and GPPS.

The flame retardant of the flame-retardant plastic in the present invention is not particularly limited, and a bromo-based flame retardant represented by a decabrom-based flame retardant, and a phosphorus-based flame retardant called Nonde force. Any compound containing a flame retardant called a flame retardant, a chlorine-based flame retardant, or a non-halogen-based flame retardant is applicable, and even a compound containing an inorganic flame retardant such as a hydroxide inorganic substance. Good.

Furthermore, the flame retardancy of the recycled flame-retardant plastic (including modified recycled flame-retardant plastic) obtained in the present invention has a flame retardancy specified by V-0 or V- ² in UL standards. It is good to be. BEST MODE FOR CARRYING OUT THE INVENTION

Examples 1-2, Comparative Examples 1-2

The test was performed using 30 TV sets collected as waste. Remove the back cover of the TV, select only those with a polystyrene (PS) mark and V-O mark engraved on the inside of the back cover, and average out those that are confirmed to be flame-retardant plastic. Diameter 6mm (3 ~ 10mm to 95 (wt% or more) to obtain about 2 Okg of crushed flame-retardant plastic. Note that polystyrene (PS) is HIPS, and some of it contains GPPS.

Next, the pulverized material was dry-blended well, divided into four pieces of 5 kg each, and the surface layer was scraped off using a dry cleaning machine (one clean separator) manufactured by Fine 'Engineering. This apparatus is provided with a means for scraping the surface layer as described in the above patent and a means for automatically discharging the generated powder. The amount of peeling (grinding rate) of the surface layer was changed by changing the stirring time (applying minute vibration). The grinding rate was calculated from the amount of dust discharged. The dust generally passes through a 20-mesh filter. By changing the grinding rate to 1 wt%, 5 wt%, 25 wt%, and 35 wt%, the physical properties of the obtained recycled flame-retardant plastic were evaluated. Table 1 shows the evaluation results.

Item Comparative Example 1 Example 1 Example 2 Comparative Example 2 Grinding rate iwt% 5Wt% 25Wt% 35Wt ° / o Flame retardant V-2 v-o V-0 v-o

I z 5.2 6.6 6.8 6.7 Overall rating X 〇〇 Δ From Table 1, it is confirmed that if the surface layer is not sufficiently stripped, the flame retardancy is poor. If the surface layer is scraped off too much, the amount of recycled resin decreases, and conversely, the recovered surface layer powder, which is a waste, is large, and the recovery rate decreases. Example 3

The TV back cover (HIPS, V-0) was reprocessed in the same manner as in Example 1, and the obtained regenerated flame-retardant plastic was mixed with the same type of virgin (HIPS, V-0, decabrom-based flame retardant blended). Then, the mixture was mixed at a regenerated material mixing ratio of 0, 5, 10, 30, 50, 75, and 100% by weight, and then repelleted to prepare a recycled flame-retardant plastic.

When the flame retardancy of the obtained recycled flame-retardant plastic was measured, it was all V-0. Table 2 shows the results of measurement of tensile yield strength, tensile rupture strength, flexural strength, flexural modulus, MFR, YZ impact strength, and elongation at break.

Physical property test conditions: Tensile test: ASTM D-790, Test condition: 3 mm / min, Bending test: ASTM D-638, Test condition: 5 mm / min, and Iz impact strength: ASTM D-256, Test condition: Meat It is 6.4mm thick with a notch.

Table 2 Recycle content (wt%) 0 5 10 20 30 50 75 100 Tensile yield strength (MPa) 21.4 21.3 21.3 21.1 20.7 20.4 19.6 19.5 Tensile breaking strength (MPa) 18.3 18.2 18.2 17.9 17.8 19 18.3 19.5 Flexural strength (MPa) 35.4 35 35.7 35.4 35.3 35.4 35 35 Flexural modulus (MPa) 2040 2040 2079 2069 2050 2079 2040 2050 Elongation at break (%) 39.3 34.7 34 32.2 3 1 34.4 24.7 27.9

I _Z value (kj / m ² ) 7.9 7.9 7.9 7.9 8 7.6 7.5 6.9

MFR (g / lOOmin) 14.8 15.2 14.5 15.7 13.6 14.4 12.8 11.8 From Table 2, it was confirmed that when the mixing ratio was up to 50% by weight, it had almost the same mechanical properties as virgin.

Example 4, Comparative Example 3

Table 3 shows the results of a sunshine weather meter light resistance test of each commercially available flame retardant PS.

Table 3

The test conditions of the sunshine weather were as follows: carbon: super long carbon, four each at the top and bottom, black panel temperature: 63 ± 3 ° C, glass filter material: eight quartz glass, and rain: present.

Next, the above-mentioned 100 Ohr irradiation (100 Ohr single-sided irradiation, double-sided irradiation) After crushing the tensile test sample to 5 mm under, peel off the surface with a dry cleaning machine manufactured by Ein 'Engineering. After performing grinding, changing the grinding rate (amount of generated dust) to 1 wt% and 15 wt%, the regenerated pellets obtained by kneading are injection-molded again to prepare test specimens. Then, physical properties were evaluated. Table 4 shows the results. In addition, the retention rate of the virgin resin before the light resistance test was performed. This is the value when the numerical value is 1 0 0

Table 4

As described above, those with a grinding rate of 15 wt% are comparable to the physical properties of virgin materials.

It has made it possible to treat flame-retardant plastic molded product waste into recycled flame-retardant plastic. This recycled flame-retardant plastic can be used alone or mixed with fresh flame-retardant plastic, and can be reused for similar applications.

Claims

The scope of the claims

(1) The flame-retardant plastic molded product recovered from the waste containing the flame-retardant plastic molded product is crushed, and the surface of the obtained crushed material is ground, and the surface layer is 3 to 30% by weight. A method for reclaiming flame-retardant plastic, which is characterized by shaving off.

(2) The method for reclaiming flame-retardant plastic according to claim 1, wherein the surface layer of the crushed material is subjected to 0.1-1.

(3) The method for regenerating a flame-retardant plastic according to claim 1, wherein the surface grinding treatment is a dry washing treatment for crushing the crushed material and / or the crushed material with the container wall to scrape the surface layer.

(4) The flame-retardant plastic molded product recovered from the waste including the flame-retardant plastic molded product is crushed, and the surface of the obtained crushed material is ground, and the surface layer is 3 to 30% by weight. A method for recycling flame-retardant plastics, which is characterized in that the pellets are scraped and then subjected to kneading to form recycled pellets.

(5) The flame-retardant plastic molded product recovered from the waste including the flame-retardant plastic molded product is crushed, and the surface of the obtained crushed material is ground, and the surface layer is 3 to 30% by weight. A method for producing recycled flame-retardant plastic, characterized by shaving off.

(6) A recycled flame-retardant plastic obtained by the method for producing a recycled flame-retardant plastic according to claim 5.

(7) Recycled in which the recycled flame-retardant plastic according to claim 6 and an unused flame-retardant plastic of the same or different kind as the recycled flame-retardant plastic are blended in a weight ratio of 5 to 95:95 to 5: 5. Flame retardant plastic.

(8) Recycled flame-retardant plastic is HIPS or GPPS containing flame retardant The recycled flame-retardant plastic according to claim 6, which is:

(8) The recycled flame-retardant plastic according to claim 6 or 7, wherein the V-0 or V-2 grade is maintained according to UL standards.