REGENERATION METHOD OF WASTED STYRENE FOAM BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a regeneration method of waste styrofoam and more particularly, to the regeneration method of waste styrofoam to regenerated expandable polystyrene (hereunder referred to as "EPS") beads having a primitive state by reducing and foaming waste styrofoam.

Generally, EPS beads having a tiny size like hulled millet are foamed to have spherical shape having an appropriate volume and size, aggregated to have appropriate open cells and further cut vertically and horizontally with a fixed length to be widely used in the fields of building materials and packaging materials.

Even if these styrofoam have been used in a variety of fields, waste styrofoam from sanitary landfills, fish markets, electronics business centers and the like arise environmental pollution. Thus, an appropriate disposal of such wastes has been highly demanded.

For this purpose, inventors have disclosed a reducing device of styrene form to reduce volume and harden by compressing waste styrofoam (Korean Patent No. 145102).

The compressed styrofoam with the reducing device has been reused in the limited fields such as reclaimed resins, soil conditioners, and building materials because it is difficult to regenerate styrofoam having primitive volume and size completely.

Therefore, it is highly demanded to develop novel mechanical technologies to regenerate waste styrofoam having primitive characters.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a regenerating method of waste styrofoam comprising: the first step of pulverizing waste styrofoam reduced with a reducing device having multi-compression system; the second step of granulating the pulverized one to have spherical shapes by a hot air heating at an appropriate temperature; the third step of producing EPS beads by supplying pentane gas; and the forth step of foaming the regenerated EPS beads by a steam heating to produce styrofoam having primitive volume and size.

Brief Description of the Drawings Fig. 1 represents one example of regenerating method of wasted styrofoam of the present invention.

Fig. 2 represents another example of regenerating method of wasted styrofoam of the present invention.

Fig. 3 represents another example of regenerating method of wasted styrofoam of the present invention.

Fig. 4 represents another example of regenerating method of wasted styrofoam of the present invention.

Fig. 5 represents a drawing indicating a degree of roundness of EPS of the present invention.

Detailed Description of the Invention The present invention is described in detail as set forth hereunder.

A regenerating method of waste styrofoam of the present invention comprising: (i) the first pulverizing step of waste styrofoam reduced with a reducing device having multi-compression system to have particles being flat shape; (ii) an aggregating step of the pulverized one to be spherical polystyrene beads with a size of 0.5-1.0 mm by heating at 50-160 °C ; (iii) the second pulverizing step of the aggregated polystyrene beads to individual spherical polystyrene beads ; (iv) a producing step of the individual spherical polystyrene beads to EPS beads by supplying pentane gas; and (v) a foaming step of the EPS beads by a steam heating to regenerated styrofoam having primitive volume and size.

Another regenerating method of wasted styrofoam of the present invention comprising: (i) the first pulverizing step of waste styrofoam reduced with a reducing device having multi-compression system to have styrofoam having flat shape; (ii) the second pulverizing step of the first pulverized styrofoam and a filtering step of the resultant to obtain flat styrofoam having a particle size of 3-5 mm; (iii) a granulating step of the twice-pulverized one to have spherical polystyrene beads with a size of 0.5-1.0 mm by heating at 50- 160 °C ; (iv) a producing step of the spherical polystyrene beads to EPS beads by supplying pentane gas; and (v) a foaming step of the EPS beads to the regenerated styrofoam by a steam heating to produce styrofoam having primitive volume and size.

Another regenerating method of wasted styrofoam of the present

invention comprising: (i) the first pulverizing step of waste styrofoam reduced with a reducing device having multi-compression system to have styrofoam having flat shape; (ii) the second pulverizing step of the first pulverized styrofoam and a filtering step of the resultant to obtain flat styrofoam having a particle size of 3-5 mm; (iii) a producing step of the pulverizing styrofoam to regenerated EPS beads by supplying pentane gas; and (iv) a foaming step of the EPS beads to the regenerated styrofoam by a steam heating to produce styrofoam.

Another regenerating method of wasted styrofoam of the present invention comprising: (i) the first pulverizing step of waste styrofoam reduced with a reducing device having multi-compression system to have styrofoam having flat shape; (ii) a producing step of the pulverized styrofoam to aggregated EPS beads by supplying pentane gas; (iii) the second pulverizing step of the aggregated EPS beads to individual EPS beads ; and (iv) a foaming step of the individual EPS beads to the styrofoam having primitive volume and size by a steam heating.

The regenerating method of waste styrofoam of the present invention is described in more detail with accompanying figures as set forth hereunder.

In Fig. 1 representing one example of regenerating method of waste styrofoam of the present invention, the waste styrofoam is compressed by the reducing device having multi-compression system which was invented from the inventors of the present invention. The spherical shape of the waste styrofoam is compressed to a laminated structure having flat shape. When the waste styrofoam having the laminated structure is pulverized as shown in Fig.

1, it is pulverized to have a potato size and most of spherical polystyrene beads

are compressed to an aggregated flat shape. This pulverized styrofoam is heated to 50-160oC, preferably 150°C, for an appropriate time. As a result, the volume of the flat polystyrene beads is reduced to aggregated spherical polystyrene beads like hulled millet having a size of 0.5-1.0 mm. Said appropriate time is the time till the flat polystyrene beads is reduced to the aggregated spherical polystyrene beads like hulled millet having a size of 0.5- 1.0 mm. And then, the aggregated polystyrene beads are pulverized again to produce individual spherical shape of polystyrene beads. Further, these individual spherical shape of polystyrene beads are regenerated to expandable polystyrene beads by supplying pentane. More particularly, pentane is passed to the individual spherical shape of polystyrene beads at room temperature. A pressure and heat are supplied while stirring to mix with the individual spherical shape of polystyrene beads homogenously. When pentane is well mixed with the individual polystyrene beads, the regenerated EPS beads are heated to foam the regenerated styrofoam having primitive volume and size by a steam heating. Additionally, a filtering process to collect the same size of particles and a coating process with general coating agent to prevent pentane from eliminating are preferred to be performed.

In Fig. 2 representing another example of regenerating method of waste styrofoam of the present invention, the waste styrofoam is compressed by the reducing device having multi-compression system as the previous example and then pulverized to obtain aggregated flat polystyrene beads having a potato size. These flat polystyrene beads are again pulverized and filtered through a sieve to obtain individual flat polystyrene beads having a size of 3-5 mm which is very thin structure. These individual flat polystyrene beads are heated to

50-160 C, preferably 150 C, to obtain individual spherical polystyrene beads having a size of 0.5-1.0 mm, followed by passing pentane with stirring to produce regenerated EPS beads which are further heated by a steam heating to foam the regenerated styrofoam having primitive volume and size.

In Fig. 3 representing another example of regenerating method of waste styrofoam of the present invention, the waste styrofoam is compressed by the reducing device having multi-compression system as the previous example and then pulverized to obtain aggregated flat polystyrene beads having a potato size. These flat polystyrene beads are again pulverized and filtered through a sieve to obtain individual flat polystyrene beads. The individual flat polystyrene beads are passed with pentane at room temperature and then heated, while stirring to mix homogenously, to obtain regenerated EPS beads having 0.5-1.0 mm, which are further filtered through a sieve to collect beads having the same size and coated with general coating agent. The regenerated EPS beads are foamed by a steam heating to regenerate styrofoam having primitive volume and size. This method is simplified compared to other methods because a hot air heating is deleted.

In Fig. 4 representing another example of regenerating method of waste styrofoam of the present invention, the waste styrofoam is compressed by the reducing device having multi-compression system as the previous example and then pulverized to obtain aggregated flat polystyrene beads having a potato size. These flat polystyrene beads are passed with pentane at room temperature, while stirring to mix homogenously, to reduce volume of the flat polystyrene beads to aggregated spherical polystyrene beads having a size of 0.5-1.0 mm and simultaneously produce regenerated EPS beads, followed by

filtering through a sieve and coating with a coating agent. The aggregated spherical EPS beads are pulverized to individual spherical EPS beads which are further foamed by a steam heating to regenerate styrofoam having primitive volume and size. The size of beads prepared by this method is divided to 4 grades of 1.6-1.18 mm, 1.18-0.85 mm, 0.85-0.6 mm, and 0.6-0.4 mm. These regenerated EPS beads having 4 grades have spherical shape.

Fig. 5 represents a roundness of the regenerated EPS beads specifying round structure. The regenerated EPS beads are in between H1 and H2 and the roundness (H1/H2) thereof can be maintained in the range of 80-90%.

Consequently, the regenerating method of waste styrofoam of the present invention provides remarkable advantages in that (i) waste styrofoam is compressed by using the reducing device having multi-compression system and this compressed flatly polystyrene beads are foamed to produce the corresponding styrofoam having primitive volume and size; and (ii) the regenerated styrofoam is aggregated to have an appropriate open cells and it can be mixed with virgin EPS beads to use for the industrial purpose such as packaging materials. And further, this process for regenerating styrofoam is simple and reduce the processing cost.