Technical Field The present invention relates to a method of extracting pulverized plastic matter from waste printed circuit boards (hereinafter, referred to as"PCBs"), and materials for civil engineering and construction using the pulverized plastic matter. More particularly, the present invention relates to a method of extracting pulverized plastic matter from waste PCBs, and materials for civil engineering and construction using the pulverized plastic matter, wherein the pulverized plastic matter extracted from the waste PCBs that are currently produced in large quantity is used as an additive for the materials for civil engineering and construction so that the materials can have superior physicalproperties.

Background Art Recently, there is a growing tendency for the quantities of production and consumption of PCBs to be rapidly increased as various kinds of electronic products with the PCBs mounted therein, such as television sets and computers, are rapidly increased.

Therefore, since waste PCBs made during production of the PCBs or collected from discarded electronic products are rapidly increased, there are problems in that manpower and costs are largely wasted on incinerating or burying the waste PCBs and serious environmental pollution occurs.

Furthermore, since the waste PCBs, which have been made of relatively expensive materials with good quality, directly go into the discard, enormous waste of resources is produced.

Disclosure of Invention The present invention is conceived to solve the above problems. An object of

the present invention is to provide a method of extracting pulverized plastic matter from waste PCBs, wherein a large quantity of the discarded waste PCBs are crushed and pulverized and then classified into metallic and plastic matters in order to extract the pulverized plastic matter to be used as an additive for construction materials.

Another object of the present invention is to provide a method of extracting pulverized plastic matter from waste PCBs, wherein pulverized granular plastic matter is chemically treated by passing through fish oil, or a coating remover, in order to enhance adhesive strength of the pulverized plastic matter with a binder for materials for civil engineering and construction.

A further object of the present invention is to provide materials for civil engineering and construction with superior physical properties using pulverized plastic matter extracted from waste PCBs, by binding a binder for the materials for civil engineering and construction with the pulverized plastic matter extracted from the waste PCBs.

According to a preferred aspect for achieving the objects of the present invention, there is provided a method of extracting pulverized plastic matter from waste PCBs. comprising the steps of classifying the waste PCBs by the material thereof with parts thereof removed ; crushing the classified waste PCBs ; pulverizing particles of the crushed waste PCBs in multiple stages to have particle sizes smaller than those of the particles of the crushed waste PCBs ; primarily separating the multi-stage pulverized particles into metallic and plastic matters by the particle size thereof by using magnetic force and vibration ; finely pulverizing the separated plastic matter to have a mean particle size ranging from 60 tm to 1 mm; and secondarily separating particles of the finely pulverized plastic matter into the metallic and plastic matters by the particle size thereof by using the vibration, specific gravity and the magnetic force.

According to another preferred aspect for achieving the objects of the present invention there is provided a method of extracting pulverized plastic matter from waste PCBs, comprising the surface-treatment step of removing impurities on surfaces of the waste PCBs with parts thereof removed by immersing the waste PCBs in a mixed bath containing a mixture of 70 wt% water. 25 wt% caustic soda (sodium hydroxide). and 5

v. t% dibutylacetylene for about 30 minutes at room temperature; the water-washing step of washing the surface-treated PCBs with water; the crushing step of crushing the washed PCBs to have proper sizes by using a hammer mill at a crush angle of 15-18 degrees; the pulverizing step of pulverizing particles of the crushed waste PCBs to form powder by using a ball mill ; and the chemical treatment step of removing ink and an outer surface coating adhering to the pulverized powder.

According to a further preferred aspect for achieving the objects of the present invention, there is provided materials for civil engineering and construction using pulverized plastic matter extracted from waste PCBs, comprising the pulverized plastic matter extracted after pulverizing the waste PCBs ; and a binder for materials for civil engineering and construction to be bound with the pulverized plastic matter.

Brief Description of Drawings FIG. 1 is a flowchart showing a fundamental process for extracting pulverized plastic matter from waste PCBs according to the present invention.

FIG. 2 is a flowchart showing another process for extracting pulverized plastic matter from waste PCBs according to the present invention.

FIG. 3 is a flowchart showing a further process for extracting pulverized plastic matter from waste PCBs according to the present invention.

FIG. 4 is a sectional view showing the state where an airport runway or a roadway on a bridge's floor slab is paved with materials using the pulverized plastic materials extracted from the waste PCBs according to the present invention.

Best Mode for Carrying Out the Invention Hereinafter, preferred embodiments of the present invention will be explained in detail with reference to the accompanying drawings.

FIG. 1 is a flowchart showing a fundamental process for extracting pulverized plastic matter from waste PCBs according to the present invention. The pulverized plastic matter for use in materials for civil engineering and construction can be extracted from the waste PCBs by using a method comprising the steps of removing parts

mounted on the waste PCBs ; crushing the waste PCBs with the parts thereof removed ; pulverizing particles of the crushed waste PCBs to have particle sizes smaller than a mean particle size of the particles of the crushed waste PCBs ; forming powder by finely pulverizing particles of the pulverized waste PCBs to have a mean particle size ranging from 60 llm to 1 mm; and classifying the finely pulverized powder into metallic and plastic matters by the particle size and material thereof.

The pulverized plastic matter that has been extracted contains, as main components, denatured polyimide for forming the PCBs, thermosetting polyphenylene ether (PPE) based resin, epoxy, fiber glass wool, and the like. The pulverized plastic matter is bounded with a binder for materials for civil engineering and construction so as to impart superior properties thereto.

Further, the classified plastic powder having the size of 60 llm to 1 mm may be molded to have a predetermined size so that it can be used as an additive for the materials for civil engineering and construction.

FIG. 2 is a flowchart showing another process for extracting the pulverized plastic matter from the waste PCBs according to the present invention. The pulverized plastic matter for use in the materials for civil engineering and construction can be extracted from the waste PCBs by using a method comprising the surface-treatment step of removing impurities on surfaces of the waste PCBs with parts thereof removed by immersing them in a mixed bath containing a mixture of 70 wt% water, 25 wt% caustic soda (sodium hydroxide), and 5 wt% dibutylacetylene for about 30 minutes at room temperature ; the water-washing step of washing the surface-treated PCBs with water ; the crushing step of crushing the washed PCBs to have proper sizes by using a hammer mill at a crush angle of 15-18 degrees ; the pulverizing step of pulverizing particles of the crushed waste PCBs to form powder by using a ball mill; and the chemical treatment step of removing ink and an outer surface coating adhering to the pulverized powder by passing it through fish oil that is a coating remover.

In the surface-treatment step, ink, various kinds of impurities and coatings on the surfaces of the waste PCBs with the parts thereof'removed are removed therefrom so that only clean bodies of the waste PCBs can be processed. Upon completion of the

surface-treatment step. impurities still remaining on the surfaces are completely removed by washing the waste PCBs with water once again.

The waste PCBs from which the impurities have been completely removed are crushed to have particle sizes of 2 x 4 mm to 3 x 6 mm by means of the hammer mill at the crush angle of 15-18 degrees. The particles of the crushed waste PCBs are then pulverized to be granular powder by means of the ball mill.

The pulverized granular powder is chemically treated by passing through the fish oil, which is a coating remover, to remove metal adhering to the granular powder.

Thus, only the pulverized plastic matter is extracted. The pulverized plastic matter that has been extracted is packaged and treated as such, so that it can be later used as an additive in the form of powder for the materials for civil engineering and construction.

FIG. 3 is a flowchart showing a further process for extracting the pulverized plastic matter from the waste PCBs according to the present invention. The process comprises the steps of classifying the waste PCBs by the material thereof with parts thereof removed; crushing the classified waste PCBs ; pulverizing particles of the crushed waste PCBs in multiple stages to have particle sizes smaller than those of the particles of the crushed waste PCBs ; primarily separating the multi-stage pulverized particles into metallic and plastic matters by the particle size thereof by using magnetic force and vibration; finely pulverizing the separated plastic matter to have a mean particle size ranging from 60 um to 1 mm; and secondarily separating particles of the finely pulverized plastic matter into metallic and plastic matters by the particle size thereof by using the vibration, specific gravity and the magnetic force.

In a further process of extracting the pulverized plastic matter from the waste PCBs according to the present invention, the waste PCBs are collected, parts are removed from the collected waste PCBs, the waste PCBs with the parts thereof removed are classified by the material thereof, and then the classified waste PCBs are crushed to have particle sizes of about 8-15 cm.

Subsequently, particles of the crushed waste PCBs are pulverized in multiple stages to have particle sizes equal to or less than 8 mm, which are smaller than those of the particles of the crushed waste PCBs.

In the primarily separating step, the multi-stage pulverized particles are separated into the metallic and plastic matters by the particle size thereof by using the magnetic force and the vibration. The separated plastic matter is finely pulverized to produce particles in the form of powder having the mean particle size ranging from 60 llm to 1 mm. In the secondarily separating step, the particles of the finely pulverized plastic matter are separated again into the metallic and plastic matters by the particle size thereof by using the vibration, the specific gravity and the magnetic force. In such way, the extraction of the pulverized plastic matter from the waste PCBs is completed.

In the secondarily separating step, only valuable metal may be extracted from the metal matter that has been separated from the pulverized plastic matter. Thus, the extracted valuable metal can be recycled.

Moreover, in the primarily separating step, the pulverized plastic matter having a mean particle size of 1. 1 mm to 5 mm is extracted and then used as an additive in the form of chips for the materials for civil engineering and construction. In the secondarily separating step, the pulverized plastic matter having a mean particle size of 60 llm to 1 mm is extracted and then used as an additive in the form of powder for the materials for civil engineering and construction.

The materials for civil engineering and construction using the pulverized plastic matter extracted from the waste PCBs were applied in various ways, and their physical properties were compared with one another in the following embodiments.

[First embodiment]-Case where the materials are applied to pavement of an airport runway or a roadway on a bridge's floor slab Upon pavement of an airport runway or a roadway on a bridge'floor slab by using the pulverized plastic matter obtained through the above processes, a primer is coated on a footing concrete surface from which impurities have been removed.

Subsequently, the pulverized plastic matter for the materials for civil engineering and construction is mixed with epoxy resin and then casting of the mixture is performed onto the primer-coated footing concrete surface.

At this time. if the construction is undertaken in an area where the severe cold

or heavy snow is expected, wire meshes may be optionally installed therein by employing a snow melting system prepared for the winter season, Further, in a case where the strength adhering to the ground is weak, as shown in FIG. 4, anchors 5 are formed in the ground 10, and"+"-shaped or disk-shaped fixing plates 1 having openings 7 for bonding upper and lower portions are installed by using anchor bolts 3 that are inserted into and mounted in the anchors 5. Subsequently, the epoxy resin mixed with the pulverized plastic matter of the present invention is cast in the openings 7. When the epoxy resin is cured, first epoxy resin layers 2 with the pulverized plastic matter bound therewith are formed.

After the first epoxy resin layers 2 with the pulverized plastic matter bound therewith are formed, the epoxy resin mixed with the pulverized plastic matter is cast again to wrap the fixing plates 1. Thus, a second epoxy resin layer 6 with the pulverized plastic matter bound therewith is formed. Additionally, if a textured plate is cast onto the top of the second epoxy resin layer 6 with the pulverized plastic matter bound therewith to form a surface-treatment layer 8 for enhancing an appearance and friction force, more solid pavement of the airport runway or the roadway on the bridge's floor slab can be achieved.

Therefore, the pulverized plastic matter of the present invention can be used as the materials for civil engineering and construction of the airport runway, the bridge's floor slab, or the like.

In such way, for the application to the pavement of the airport runway or the roadway of the bridge's floor slab, as shown in Table 1, epoxy resin and resin mortar that have been bound with the pulverized plastic matter extracted from the waste PCBs, and epoxy resin and resin mortar that have not been bound with the pulverized plastic matter extracted from the waste PCBs were tested and compared with one another in view of their physical properties such as hardness, tensile strength, flexural strength, compressive strength, shear bond strength and pot life pursuant to a test method of the Korean Industrial Standards Mark (KSM). In addition, their viscosities were tested by using a Brookfield viscometer.

TableI Results of measurement Addition of the pulverized plastic For general use Test items Unit matter extracted from Test method waste PCBs Epoxy Resin Epoxy Resin resin mortar resin mortar Hardness HDD 83 60 84 84 KSM3043-95 Tensile strength kgf/mm2 3.51 3.36 4.35 4. 35 KSM3015-91 i Flexural strength kgf/mm2 4. 13 4.6 4.87 4. 87 KSM305-92 I Compressive kgílmm2 8. 54 9. 2 10. 42 10. 42 KSM3015-92 strength Shear bond strength kgf/mm2 0.82 1.03 1.07 1.07 KSM3732-91 Pot life Hour 1 1 1 1 KSM5000-95 Main cps 640 2100 2100 2100 Viscosity material Brookfield I (25°C) Curing cps viscometer 275 111 111 111 agent

It can be seen from Table 1 above that the epoxy resin and resin mortar with the pulverized plastic matter added thereto are superior to the general epoxy resin and resin mortar to which the pulverized plastic matter has not been added, in view of the tensile, flexural and compressive strengths, Therefore, the roadway of the bridge's floor slab or the airport runway paved with the epoxy resin and resin mortar with the pulverized plastic matter added thereto can have superior durability and thus prolonged life.

[Second embodiment]-Construction of a high-strength structure

Upon formation of a high-strength structure of a building, high-strength concrete or building materials should be employed. In this second embodiment of the present invention, the pulverized plastic matter extracted from the waste PCBs and the epoxy resin were mixed in a ratio of (2-3) : 1 so that they can be used for construction of the high-strength structure. After the structure of the building was constructed using the mixture of the pulverized plastic matter and the epoxy resin mixed as such, the physical properties of the structure was tested.

As a result, the high-strength structure containing the pulverized plastic matter of the present invention had the mechanical properties of the compressive strength of 900 kgElcm2 or more, the tensile strength of 450 kgf/cm or more, and the flexural strength of 400 kgf/cm"or more. Thus, the structure having superior durability can be constructed in building works.

[Third embodiment]-Use for strength reinforcement of concrete and use for replacement of artificial silica sand or small-sized aggregate Pulverized plastic matter corresponding to standards of 1 to 5 grades of silica sand or having a size of (2-3 mm) x (30-100 mm) in width and length among the pulverized plastic matter extracted from the waste PCBs of the present invention can be used for reinforcement of the strength of concrete and for replacement of artificial silica sand or fine aggregate.

In this third embodiment of the present invention, cement, sand, the pulverized plastic matter and gravel were mixed in a ratio of 1: 1 : I : 3. The mixture was used for the reinforcement of the strength of the concrete and for the replacement of the artificial silica sand or fine aggregate.

The concrete mixed as such can solve the problem that it is conglomerated when mixed in the form of the existing glass wool. In addition, since the concrete is uniformly distributed, prevention of occurrence of cracks in a concrete structure and remarkable increase of the mechanical strength thereof can be achieved.

[Fourth embodiment]-Use of an extender or additive for a molded product

In this fourth embodiment of the present invention, powder of the pulverized plastic matter extracted from the waste PCBs was used as an additive or extender for a molded product such as polyvinyl chloride (PVC), paint, and materials for replacement of a road support or aluminum frame, As shown in Table 2, PVC with the pulverized plastic matter added thereto and general PVC to which the pulverized plastic matter has not been added were tested and compared with each other in view of their physical properties pursuant to Japanese Industrial Standards (JIS).

As a result, a molded product fabricated by adding the pulverized plastic matter of the present invention as an additive or extender is superior to a general molded product (general PVC) to which the pulverized plastic matter has not been added, in view of the characteristics and properties of their powder. Particularly, the molded product fabricated according to the present invention has an excellent degree of polymerization to enable both adhesive strength in the molded product and durability of a finished product thereof to be enhanced.

Table 2 PVC with the pulverized plastic matter extracted GeneralPVC Test method from the waste PCBs added thereto Degree oC 1000 ~ 50 1100 ~ 50 potymerization K-value 64.5 # 66.7 66.7 # 68.5 Apparent Kpec) fic 0.45 # 0.60 0.45 # 0.55 JIS K-6721 gravity (g/cc) Volatilecomponent (%) 0.30 or less 0.30 or less . _ _ Content of VacM (%) - - Granularity (%) 100% 100%

[Fifth embodiment]-Use for replacement of artificial marble or a building panel The pulverized matter generated according to the present invention and powder containing fiber glass as a main component were mixed in a proper ratio such as 1: 1 or 1: 2. Resin falling within an unsaturated polyester group is further added to the mixture in a ratio of 20-40 wt%. This mixture is then inputted into a mold having a shape suitable for its use, and subsequently molded therein for about 20 minutes at temperature of 180 t under proper pressure (20-30 kgflcm').

The molded product has advantages in that its strength is corrected by the fiber glass component and the pulverized matter of the PCBs and its weight is lower than that of the existing building panel or artificial marble so that when it is used as external ornament or interior decoration materials of a building, a structure constructed by the external ornament or interior decoration materials can be lightened and thus load of the structure can be relieved.

Further, color and characteristics according to the properties and states of the PCBs appeared on the external appearance of the molded product so that it was elegant and similar to natural marble. Alternatively, addition of stone powder or pigment resulted in products having various textures and colors.

[Sixth embodiment]-Use of the pulverized plastic matter as an additive for Ascon In this sixth embodiment of the present invention, the pulverized plastic matter is mixed with coarse aggregate, fine aggregate, stone powder and asphalt and they are heated in a mixing vessel at mixing temperature of 160 l 15°C in order to produce Ascon.

In Table 3 below, general Ascon and Ascon with the pulverized plastic matter extracted from the waste PCBs added thereto were compared with each other in view of their physical properties.

Table 3 Ascon with the pulverized plastic matter extracted Test items General Ascon Increased rate from the waste PCBs added thereto Reduction by 30 Strain 0.1824 0.0065 times Dynamic stability Increase by 30 230 6, 550 (times/mm) times Increase by 1.6 Toughness 21.86 34.96 times Ultimate tensile Increase by 1 2 9. 92 12. 14 strength (kg/cm2) times Deflection upon 3.28 3.28 - destruction (mm) Increase by 1. 18 Sliding resistance 52.2 61. 8 times Recovery increase by 1.08 20°C 3.757 4.090 elastic times modulus Increase by 1.4 40t 622 871 (MPa) times

As shown in Table 3 above, the Ascon containing the pulverized matter of the waste PCBs had the reduced strain, high resistance against plastic deflection and occurrence of cracks resulting from excellent physical properties of the dynamic stability and tensile strength, and enhanced durability, as compared with those of the general Ascon. In addition, its strength was enhanced due to glass wool contained in the pulverized matter. Thus, the highly economical functional Ascon was obtained.

[Seventh embodiment]-Addition of the pulverized plastic matter to concrete, mortar and paint In this seventh embodiment of the present invention, concrete, mortar and paint with the pulverized plastic matter added thereto and general concrete, mortar and paint to which the pulverized plastic matter has not been added were tested and compared with each other in view of their physical properties. The comparison results are shown in Tables 4 and 5 below.

Table 4 Addition of the pulverized General Unit matter of the waste PCBs Test method Concrete Mortar Concrete Mortar Compressive Kg/cm2 229 250 238 310 KS L 5105 strength i Tensile Kg/cm2 27 33 35 37 KS riz 5104 strength Ftexura) Kg/cm2 42 68 53 75 AS1 M C 384 strength Table 5 paint with the pulverized plastic General paint matter extracted from the waste PCBs added thereto Hardness 50 ~ 5 70 ~ 5 Tensile strength 30 ~ 10 50 ~ 10 Elongation (%) 700 ~ 200 1000 ~ 200 Cold resistance -40°C -40°C

It can be seen from the test results shown in Tables 4 and 5 above that mortar and paint, the concrete, mortar and paint containing the pulverized plastic matter of the present invention had superior hardness, tensile, flexural, and compressive strengths, and shear bond strength, as compared with the general concrete.

Therefore, it is possible to allow Ascon, concrete, epoxy resin mortar, paint and molded products to have superior properties by binding the pulverized plastic matter extracted from the waste PCBs of the present invention with a binder for materials for civil engineering and construction including epoxy resin, cement, sand and gravel, coarse aggregate, fine aggregate, stone powder, asphalt, etc.

Although the present invention has been described in connection with the specific embodiments, it is apparent to those skilled in the art that various modification and changes can be made thereto without departing from the technical spirit and scope of the present invention. These modification and changes fall within the scope defined by the appended claims.

Industrial Applicability As described above, since the present invention recycles the waste PCBs, environmental pollution produced when incinerating or burying the waste PCBs can be prevented. Further, since materials for civil engineering and construction bound with the pulverized matter of the waste PCBs have superior properties, there is an advantage in that life of a structure constructed by means of civil engineering and construction works can be prolonged.