FLAME RETARDING FOAM COMPOSITION UTILIZING WASTE MATERIAL AND FABRICATING METHOD THEREOF TECHNICAL FIELD The present invention relates to a flame retarding foam composition using a waste material and a fabricating method thereof, and more particularly, to a flame retarding foam composition which uses waste polyethylene (WIPE), waste ethylene- vinyl copolymer (W-EVA), waste rubber, or ground tire rubber (GTR) as the waste material for a base resin, if necessary, blends one or more ingredients out of virgin polyethylene, nitrile rubber and ethylene-propylene copolymer (EPDM) and then adds an inorganic-based and phosphorus-based flame retarding agent, foaming agent, crosslink agent or other addition agent, thereby efficiently recycling the waste plastic, the waste rubber and the ground tire rubber and, at the same time, providing products which are environment-friendly and have a high stability, mechanical and physical property, particularly, a high flame retardancy and economic efficiency, the composition being utilized as an economical recycled product while securing the high safety, the mechanical and physical property, the high flame retardancy and economic efficiency and recycling the waste materials when being applied in various fields such as construction materials, vehicle parts, sport products, other industrial products and so forth by extrusion molding, compression molding or injection molding, and a fabricating method thereof.

BACKGROUND ART In the case of existing foam (polyolefin, etc. ), it is a molding composition, which is widely utilized in various fields such as construction, building, vehicle, sport product and others. It is required to have the flame retardancy due to various regulations in the interior and all the countries of the world based on environment and safety. However, since it has a low level of the flame retardancy and is also noxious to the human body, its application range is gradually reduced. Furthermore, although there is a little difference according to a material used as the base material, the application range is getting segmented according to its characteristics because of a flood of relevant enterprises and diversification of similar materials. At the result, the application range is gradually reduced from an existing wide field to a specific field.

Further, due to the development of substitute similar materials, etc. , there is occurred limitless competition in a market for the foam composition. Therefore, there is raised a necessity for developing an economical product having the good physical property and flame retardancy.

In the case of the foam, the flame retardancy and the economic efficiency are primarily required. However, since most of the enterprises participating in the production of the foam are medium and small-sized enterprises insufficient to research basis and skilled technical manpower, they still fabricates the foam, which has the low flame retardancy and noxious to the human body, using expensive virgin materials and a halogen-based flame retardant. Therefore, the added value of the

product is rapidly reduced, and thus the price competitiveness of the product is deteriorated.

For example, although there is a little difference according to its specification, a conventional polyethylene foam composition, which has not the flame retardancy, comprises 0. 8-0. 9 parts by weight of a crosslink agent, 22-24 parts by weight of a foaming agent and 1-1. 5 parts by weight of a colorant, based on 100 parts by weight of a low density polyethylene resin. The composition of thé. foam is generalized because of the flood of the relevant enterprises, as described above.

In the case of a flame retarding foam having a limiting oxygen index (LOI) of 26 determined by ASTM D 2863, as one of well-known conventional flame retarding polyolefin foams, there has been described a composition of the foam, in which the flame retardant and other addition agents are added to a resin comprised of only a low density polyethylene (LDPE) and an ethylene-vinyl copolymer (EVA) or blended them (Korean Patent Publication No. 10-1997-042714).

For example, although there is a little difference according to its specification, the conventional flame retarding polyolefin foam composition comprises 1-20 parts by weight of a bonding agent, 10-30 parts by weight of a foaming agent, 50-200 parts by weight of an inorganic-based flame retardant, 10-50 parts by weight of an organic halogen-based flame retardant, 0. 7-2. 0 parts by weight of a crosslink agent, based on 100 parts by weight of a resin composition in which each of the LDPE and

the EVA is independently used, or two and more resins are mixed, and then a functional rubber alone or two and more is further mixed so as to provided a high elastic property.

Meanwhile, there has been described a waste material utilizing technique for fabricating various structures using a waste plastic and a ground tire rubber in Korean patent No. 180216 by the applicant. Herein, the ground tire rubber and the waste plastic are blended with each other and a crosslink agent, which is radicalized, such as cumene hydroperoxide and dicumyl peroxide, etc. is instantaneously cross-linked at a proper high temperature and then the results are injected or extruded so as to be used as pavement blocks, flooring materials, substitutes for steel reinforcements and so force. However, in the well-known technique, the result is a simple molded work piece which has not the foaming property. In case the foaming property is endued to the resin such as the waste plastic material, etc. , since the physical property may be degenerated by the waste plastic, and thus the quality of a product may be lowered, it is difficult that the conventional composition is applied to the foam composition as it is.

In other words, since the conventional technique basically had a different application from a structure of the foam, the technique for recycling the waste materials, which had an advantage in an economical aspect, could not be applied to the foam.

In order to solve the conventional problems, the applicant has suggested"a foam composition using a waste material and a foam using the same"disclosed in

Korean Patent Application No. 10-2001-0011276. There was disclosed a useful technique for preparing the economical foam, which has not flame retardancy, utilizing the waste material. However, the applicant could not be satisfied with that. Hence, as part of the development of a preferred composition utilizing various high-polymer materials including the waste rubber, the present invention is proposed.

DISCLOSURE OF THE INVENTION As described above, in the conventional polyolefin foam composition, since the application range is gradually reduced due to the flood of the relevant enterprises and the development of substitute similar materials, etc. , there is occurred limitless competition in a market for the foam composition. Therefore, there is raised a necessity for developing an economical product having the good physical property and flame retardancy. Nevertheless, since the expensive virgin materials and a halogen-based flame retardant, which is noxious to the human body, are actually used in fabricating the foam composition, the added value of the product is rapidly reduced, and thus the price competitiveness of the product is deteriorated. Therefore, it is necessary to develop an economical and high-quality product using the economical materials.

Therefore, it is an object of the present invention to provide a flame retarding foam composition which uses waste plastic (W-PE, W-EVA), waste rubber, and ground tire rubber (GTR), if necessary, blends one or more ingredients out of virgin polyethylene, nitrile rubber and ethylene-propylene copolymer (EPDM) and then adds an inorganic-

based and phosphorus-based flame retarding agent or other addition agent, in order to improve flame retardancy and economic efficiency as one of the shortcomings in the conventional polyolefin foam composition, thereby efficiently recycling the waste plastic and, at the same time, providing products which are environment-friendly and have a high safety, mechanical and physical property, particularly, a high flame retardancy and economic efficiency.

It is another object of the present invention to provide a flame retarding foam fabricated using the composition as described above.

BRIEF DESCRIPTION OF THE DRAWINGS The above objects and other advantages of the present invention will become more apparent by describing in detail-preferred embodiments thereof with reference to the attached drawings in which: Fig. 1 is a photograph of an electron microscope showing a dispersion (B) of an addition agent and a cell structure (A) in a foam sample 1 according to a first embodiment of the present invention; Fig. 2 is a photograph of an electron microscope showing a dispersion (B) of an addition agent and a cell structure (A) in a foam sample 4 according to the first embodiment of the present invention; Fig. 3 is a photograph of an electron microscope showing a dispersion (B) of an addition agent and a cell structure (A) in a foam sample 7 according to the first

embodiment of the present invention; Fig. 4 is a photograph of an electron microscope showing a dispersion (B) of an addition agent and a cell structure (A) in a foam sample 8 according to the first embodiment of the present invention; Fig 5 is a photograph of an electron microscope showing a dispersion (B) of an addition agent and a cell structure (A) in a foam sample 11 according to the first embodiment of the present invention; Fig. 6 is a photograph of an electron microscope showing a dispersion (B) of an addition agent and a cell structure (A) in a foam sample 13 according to the first embodiment of the present invention; Fig. 7 is a photograph of an electron microscope showing a dispersion (B) of an addition agent and a cell structure (A) in a foam sample 14 according to the first embodiment of the present invention; Fig. 8 is a photograph of an electron microscope showing a dispersion (B) of an addition agent and a cell structure (A) in a foam sample 15 according to a second embodiment of the present invention; Fig. 9 is a photograph of an electron microscope showing a dispersion (B) of an addition agent and a cell structure (A) in a foam sample 17 according to the second embodiment of the present invention; Fig. 10 is a photograph of an electron microscope showing a dispersion (B) of an

addition agent and a cell structure (A) in a foam sample 23 according to the second embodiment of the present invention; Fig. 11 is a photograph of an electron microscope showing a dispersion (B) of an addition agent and a cell structure (A) in a foam sample 28 according to the second embodiment of the present invention; Fig. 12 is a photograph of an electron microscope showing a dispersion (B) of an addition agent and a cell structure (A) in a foam sample 29 according to the second embodiment of the present invention; Fig. 13 is a photograph of an electron microscope showing a dispersion (B) of an addition agent and a cell structure (A) in a foam sample 32 according to the second embodiment of the present invention; Fig. 14 is a photograph of an electron microscope showing a dispersion (B) of an addition agent and a cell structure (A) in a foam sample 38 according to the second embodiment of the present invention; Fig. 15 is a photograph of an electron microscope showing a dispersion (B) of an addition agent and a cell structure (A) in a foam sample 39 according to the second embodiment of the present invention; Fig. 16 is a photograph of an electron microscope showing a dispersion (B) of an addition agent and a cell structure (A) in a foam sample 40 according to the second embodiment of the present invention; and Fig. 17 is a photograph of an electron microscope showing a dispersion (B) of an

addition agent and a cell structure (A) in conventional foam.

BEST MODE FOR CARRYING OUT THE INVENTION To achieve one of the aforementioned objects of the present invention, there is provided a flame retarding foam composition comprising a resin component comprised of waste plastic, waste rubber and ground tire rubber, and one or more addition agent selected from a flame retardant, a crosslink agent, a foaming agent, a lubricant, a plasticizer, and a stabilizer, wherein the resin component comprises 0-100 weight percent of waste polyethylene (W-PE), 0-100 weight percent of waste ethylene-vinyl copolymer (W-EVA), 0-30 weight percent of waste rubber (W-RUBBER), 0-40 weight percent of ground tire rubber (GTR), 0-100 weight percent of polyethylene (PE), 0-30 weight percent of nitrile rubber and 0-50 weight percent of ethylene-propylene copolymer, and the flame retardant comprises 20-250 parts by weight of AI (OH) 3, 20~120 parts by weight of Mg (OH) 2, 0-20 parts by weight of magnesium silicate, 0-50 parts by weight of zinc borate, 0-50 parts by weight of zinc sulfide, 0~30 parts by weight of Sb2O3, 0-30 parts by weight of Sb205, 0~50 parts by weight of 3- (Hydroxyphenylphosphinyl) propanoic acid (H-205) or 9, 10-Dihydro-9-oxa-10- [2, 3-di- (hydroxyethoxy) carbonylpropyl]-10-phosphaphenanthrene-10-oxide (H-201), 0-50 parts by weight of Tris (chloroisopropyl) phosphate (TCPP) or Tris (2-chloroethyl) phosphate (TCEP), 0-50 parts by weight of diphenylchresylphosphate (DPK), 0-10 parts by weight of red phosphorous, 0-50 parts by weight of chlorinated paraffin and 0-30 parts by

weight of loess, as flame retardants, based on 100 parts by weight of the resin components, wherein the total content of the flame retardant is 120-290 parts by weight.

According to the present invention, 2-25 parts by weight of the crosslink agent, 10-40 parts by weight of the foaming agent, 0-10 parts by weight of the lubricant as the addition agents are mixed with a complex of the resin and the flame retardant at a temperature of 110~138°C, and then the result is extruded, pressed or injected to fabricate the foam composition.

Now, preferred embodiments of the present invention will be described in detail with reference to the annexed drawings.

An example of components of a composition of the present invention comprises 0-100 weight percent of waste polyethylene (W-PE), 0~100 weight percent of waste ethylene-vinyl copolymer (W-EVA), 0-30 weight percent of waste rubber (W-RUBBER), 0-40 weight percent of ground tire rubber (GTR), 0~100 weight percent of polyethylene (PE), 0-30 weight percent of nitrile rubber and 0-50 weight percent of ethylene- propylene copolymer, as resin components, and 20-250 parts by weight of AI (OH) 3, 20-120 parts by weight of Mg (OH) 2, 0-20 parts by weight of magnesium silicate, 0-50 parts by weight of zinc borate, 0-50 parts by weight of zinc sulfide, 0-30 parts by weight of Sb203, 0-30 parts by weight of Sb2O5, 0-50 parts by weight of 3- (Hydroxyphenylphosphinyl) propanoic acid (H-205) or 9, 10-Dihydro-9-oxa-10- [2, 3-di-

(hydroxyethoxy) carbonylpropyl]-10-phosphaphenanthrene-10-oxide (H-201), 0-50 parts by weight of Tris (chloroisopropyl) phosphate (TCPP) or Tris (2-chloroethyl) phosphate (TCEP), 0-50 parts by weight of diphenylchresylphosphate (DPK), 0-10 parts by weight of red phosphorous, 0-50 parts by weight of chlorinated paraffin and 0-30 parts by weight of loess, as flame retardants, based on 100 parts by weight of the resin components, wherein the total content of the flame retardant is 120-290 parts by weight.

The composition further comprises 2-25 parts by weight of a crosslink agent, 10-40 parts by weight of a foaming agent, 0-2 parts by weight of a foaming supplement agent, 0-10 parts by weight of an internal release agent, 0-10 parts by weight of an external release agent, 0-2. 5 parts by weight of a stabilizing agent, 0-50 parts by weight of a plasticizer and 0-5 parts by weight of a heat transfer accelerator.

Particularly, according to a preliminary experiment, the W-PE as a waste material has a molecular weight of about 5000-15, 000 which is smaller than that of the virgin PE, and the W-EVA also has a small molecular weight 1/2-2/3 times the molecular weight of the virgin EVA. Therefore, the W-PE and the W-EVA are easily cross-linked in comparison with the virgin materials thereby making a foaming process easier. The GTR as the waste material is a crosslink rubber having the most stable structure. In the case of the GTR in the state of fine powder, the dispersion of the GTR in a matrix resin is easily achieved. The GTR also has good flame retardancy. Further, since it is easy to form a char on a surface in a burning state, it serves to form an insulating layer on a

surface and prevent burning of the inside.

In the present invention, the resin composition, as a waste material which is preferably utilized in an aspect of economic efficiency and recycling, typically comprises W-PE, W-EVA, W-RUBBER, GTR, and if necessary, a blend with virgin PE, nitrile rubber, and ethylene-propylene copolymer (EPDM). Particularly, the GTR, which is preferably utilized for the present invention, is formed of powder of a waste tire. Considering that it has high chemical stability and a low content of a contaminant, it can be used as a good filler of a polyolefin blending material. Further, the tenacity of the tire rubber having a large content of carbon black can be harmonized with a plastic, while the GTR is already cross-linked, and it has high UV resistance and high chemical stability, and active carbon, etc. , contained therein is also suitable for a particle reinforcing compound material. i Therefore, in case the GRT is properly blended with other materials, it provides a good property. This component has a great influence on a mechanical characteristic of the compound material according to a size of the particle. If the size of the particle is increased, there may be generated a trouble when bonding to an interface. In most cases, since a tension property is degenerated, it is preferable that the GTR is used in the powder state. Therefore, the particle of the present invention preferably has a size of 0.5mm or below. However, there is not limitation in the size of the particle.

As a reference, the composition of the GTR used in the present invention is as ., follows.

Table 1 Analysis item pCa | PC + LTb | TBC Rubber percent Rubber percent Rubber percent Kinds of rubber polymer NR 20 40 70 Mixing rated SBR 80 45 20 (%) BR 15 10 Amount of rubber polymer Direct method 23. 7 40. 2 Indirect method 47. 6 44. 6 54. 1 Specific gravity 1. 16 1. 15 1. 14 Acetone extractives (%) 19.4 16.9 12.5 Chloroform extractives (%) 1. 40 1. 20 Alcoholic KOH solution Extract(%) 0.5 0.4 Sulfur(%) 1.7 1.7 Organic sulfure (%) 0.02 0.03 Inorganic sulfur (%) 0.5 Lime (%) 3. 1 4. 2 3. 8 Active carbonf 30.7 26.3 Si02 (%) 0. 5 0. 4 Tir2 (%) 0. 1 ZnO (%) 1. 6 1. 2 CaO (%) 1. 6 0. 4 Fe203 + Al2O3(%) 0.3 0.1

In the table 1, a reference symbol a designates a tire of an automobile, b designates a tire of a pickup, c is a tire of a truck or a bus, d is a value of a gas chromatography, e is a value of a sodium sulfite method, and f is a value of a nitrate analysis method.

According to the result of a component analysis, a tire is mainly comprised of natural rubber (NB), styrene-butadiene rubber (SBR), butadiene rubber (BR) and so force. A table 2 shows an analysis result in which a combination state of the above- I mentioned components is analyzed by each part of the tire in each case of the automobile and the truck.

Table 2 Automobile Truck Tread SBR-BR NRa-BR or SBR-BR Belt NR NR Carcass NR-SBR-BR NR-BR Sidewall (black) NR-SBR or NR-BR NR-BR Sidewall (white) NR-SBR-EPDM-IIR"- Liner NR-SBR or NR-SBR-IIR NR-IIR

In the table 2, a reference symbol a means that polyisoprene rubber (IR) is comprised, and b means that isobutylene-isoprene rubber (IIR) is comprised.

As described above, in the present invention, waste materials such as W-PE, W- EVA, W-RUBBER, GTR are used as a base resin, if necessary, blending PE, NBR and EPDM. The waste materials are efficiently treated by a recycling process, so that physical properties such as mechanical characteristic and chemical stability, etc.

Accordingly, the waste materials can be utilized as a foam composition that is very useful and environment-friendly. In addition, since the foam composition can be fabricated in a lower price, economic efficiency can be also maximized. In the present invention, one of the above-mentioned seven ingredients is used, two or more or all of them may be used.

Further, according to the present invention, considering environment and safety, a halogen-based flame retardant is not used. Instead, an inorganic-based flame retardant (e. g., AI (OH) 3, etc. ) and a phosphorous-based flame retardant are used, thereby maximizing flame retardancy. Generally, a halogen compound stabilizes a radical generated in a gas phase, thereby having the flame retarding effect. The mechanism is inferred by a chemical equation 1 as follows.

Chemical equation 1 HO-+HX- HOH +X-irreversible reaction X-+ RH- HX +R reversible reaction (stopping of chain reaction) XO-+-OH--- HX + 02 (reducing a concentration of active OX and XOH and stopping chain reaction, thereby obtaining the flame retarding effect) X + O + M --# XO + M X2 + 0-- XO-+ X- (obtaining an effect of generating noncombustible gas during decomposition and blocking generation of 02) O + OX --# O2 + X In the chemical equation 1, an active radical like OH radical generates heat through a chemical reaction during combustion. Latent heat generated at that time functions as an energy source for burning a nearby combustible material.

Meanwhile, as described in the equation, a flame retardant reduces a concentration of 0-and-OH which are active radicals and stops a chain reaction, thereby providing the flame retarding effect. The cutting of a C-X combination during

combustion is an endothermic reaction. It has the effect of reducing heat of combustion of the combustible material. Further, it has also the effect of generating noncombustible gas during decomposition and blocking the generation of oxygen. Therefore, the actual flame retarding effect is provided by HX. The HX is reacted and converted into an X radical as a low energy source. The HX functions as an oxidation catalyst of the combustible material. An oxidized material has a ring structure, thereby producing a char as a carbon complex. The carbon complex blocks the oxygen and the latent heat and serves to aid the combustible material to be kept below a combustion region.

In the present invention, an inorganic-based and phosphorous-based material is employed instead of a halogen-based material due to noxiousness to the human body.

For example, aluminum hydroxide, antimony oxide, magnesium hydroxide, a boron containing compound, etc. , may be used as the inorganic-based flame retardant. For example, H-205 (a naming) and H-201 (a naming), etc. , may be used as the phosphorous-based flame retardant. Unlike an organic-based flame retardant, the inorganic-based flame retardant is not volatilized by heat and also generates noncombustible gas such as H20, C02, S02, HCI during decomposition. A chemical reaction at this time is almost an endothermic reaction. In addition, it dilutes the combustible gas in a gas phase and it is coated on a surface of a plastic to block the oxygen. At the same time, it has an effect of cooling the plastic through the endothermic reaction on a surface of a solid phase and also reducing'generation of thermal decomposition materials. For example, the aluminum hydroxide and the magnesium

hydroxide generate water after decomposition as described in chemical equation 2. At this time, the endothermic reaction is accompanied and thus the flame retardancy is provided.

Chemical equation 2 2AI (OH) 3 + heating ---# Al2O3 + 3H2O - 298KJ/mol Mg (OH) 2 + heating MgO + H20-328KJ/mol Antimony trioxide and antimony pentaoxide may be used as the antimony oxide.

The antimony oxide is not used as it is, but used as a supplement agent for increasing a flame retarding effect of a halogen contained flame retardant. The mechanism is inferred as follows. That is, SbCl3 generated in each stage of reactions of a chemical equation 3 has an effect of lowering an temperature of the plastic through the endothermic reaction and also serves as a radical interceptor such as HCI and HBr. There is a view that all of SbCI3 and SbOCI reduce a discharging speed of halogen at a combustion region so as to increase a time for serving as the radical interceptor, thereby increasing the flame retarding effect.

Furthermore, since generated heavy gas encloses the surface of the solid phase, the approach of the oxygen is blocked and thus the flame retarding effect is generated.

This reaction mechanism can be defined as follows.

Chemical equation 3 Sb203 + 2HCI (maintained at ~250°C)---# 2SbOCl + H2O 5SCOCI (maintained at 245-280°C)- 804050 + SbCI38

4Sb405CI2 (maintained at 410~475°C)---@ 5Sb304CI + SbCI38 3Sb3O4Cl (maintained at 475-565°C)-- 4Sb203 + SbCl38 Sb203 (S) (maintained at 685°C)---@ Sb203 (i) The phosphorous-based flame retardant has a specific fire prevention effect with respect to a macromolecule having large hydroxy. It is known that the mechanism is caused by that an added phosphorous compound as described in chemical equation 4 promotes a dehydration reaction of a macromolecule of a basic material, and thus a crosslink is occurred and a noncombustible carbonaceous char is formed.

Chemical equation 4 <BR> <BR> -H2O<BR> 2H3PO4 # H4P2O7 pyrophosphoric acid <BR> -H2O. <BR> <P> H3PO4 # HPO metaphosphoric acid At this time, pyrophosphoric acid and metaphosphoric acid existed on the surface serves to increase formation of the char through the dehydration effect. The metaphosphoric acid is easily reacted. It becomes difficult that the heat is transferred to the inside of the material due to the generated char. Therefore, the char functions as an insulating layer. Water generated during the dehydration reaction serves to dilute a concentration of the combustible gas and thus increase the fire prevention effect.

Further, since the generated carbonaceous intermediate is converted into the char, an amount of generated smoke is remarkably reduced.

In the present invention, considering an aspect of environment and influence exerted to workability, a halogen-based flame retardant is not employed to fabricate an environment friendly composition. Preferably, AI (OH) 3, Mg (OH) 2, magnesium silicate, zinc borate, zinc sulfide, Sb203, Sb205, and loess are used as an inorganic-based flame retardant. Further, it is also preferable that one of H-205 (a naming), H-201 (a naming), DPK (a naming), red phosphorous, TCEP (a naming), TCPP (a naming) is used as a phosphorous-based flame retardant in the aspects of environment and flame retardancy.

In the present invention, all of the fourteen components may be used, or one or more component may be selectively used.

The loess, which is preferably used in the present invention, includes kaolin mineral (Al203X2SiO2XnH20) and designates a component such as montmorillonite (AI203X4Si02X6H20), pyrophillite (Al203X4SiO2XH20), illite {KAI2 (0Hk [AISi3 (0, 0H) 1o]}, talc (3MgOX4SiO2XH20) and so force. It is possible to intercalate an organic material according to a kind of loess. Further, since the loess has a high specific surface area of about 800m2/g or more, it serves as an absorbent, and it also may be used as efficient filler due to high absorbing power.

A foaming agent used as an addition agent in the present invention includes an organic chemical foaming agent such as, for example, azodicarbonamid group (ADCA, AC-1000) as azo-based compound or N, N'-dinitrosopentamethylenetetramine : DPT),

and an inorganic chemical foaming agent such as sodium bicarbonate (a naming, kycerol-91). In order to control a temperature and a foaming property influenced on the workability and productivity, preferably, a urea-based foaming supplement agent (cellex- A) may be used as a foaming supplement agent, and ZnO may be used as a heat transfer accelerator.

Furthermore, a crosslink agent used in the present invention is a peroxide crosslink agent. Isopropylbenzene or dicumylperoxide (DCP) are preferably used as the peroxide crosslink agent at a proper rate as described above.

Considering an influence on a uniform cell and a foaming speed according to use of a large amount of filler, Ba-Zn based stabilizer is used as a stabilizer of the present invention. For example, it is preferable that BZ-806F and BZ-119 are used.

Considering the. workability and the foaming property, diethylhexylphthalate (DOP), paraffin oil (P3-P6) and diphenylchresylphosphate (DPK) are preferably used as a plasticizer. Further, it is preferable that polyethylene wax (LC-102N), which is a rubber processing aid, and MMA-based acrylic processing aid are used as an internal release agent, and stearic acid are used as an external release agent in consideration with extruding ability.

The flame retarding foam composition of the present invention, as described above, is mixed, preferably at a temperature of 110~138°C to be molded, and then extruded, compressed or injected to fabricate various types of molds.

As described above, a method of fabricating a composition according to the

present invention will be described in each preferred embodiments. However, the embodiments are just examples according to applications. The present invention is not limited to the embodiments. In each embodiments, a symbol % designating the content of the component means a weight percent.

Further, W-PE is an abbreviation of waste polyethylene, W-EVA is waste ethylene-vinyl copolymer, W-RUBBER is waste rubber, GTR is ground tire rubber, V-PE is virgin polyethylene, NBR is nitrile rubber and EPDM is ethylene-propylene copolymer.

First embodiment: blend of resin/addition agent [I] The inventor had observed thermo dynamical and dynamical actions according to a composition rate, a temperature and a time of a blend of a resin and an addition agent, and then examined then in connection with flame retardancy and foaming property (foaming rate, cell structure, surface state, etc.). Particularly, the resin comprises W-PE, W-EVA, W-RUBBER, and GTR, if necessary, a small amount of V-PE, NBR and EPDM, considering economic efficiency and environment problem. A composition rate of the resin, a composition rate of the resin and a flame retardant, a content and a kind of the flame retardant, and a content and a kind of other addition agent are regulated.

The composition rates of the resin components are provided in a table 3. A blending process was carried out at a temperature of 110-138°C and 50 RPM for 20-25 minutes in a rheomixer (HAKE). An extruding process was carried out at a temperature of 110~138°C and 5 Rs for 1-3 minutes in a mini-max molder (Bau. 915L). And a

foaming process was carried out at a temperature of 120~210°C in an oven (HB-503M).

Examining a surface state, a foaming rate and a cell structure after the foaming process performs an examination of the foaming property. For the examination of flame retardant, an LOI (limiting oxygen index) test is performed with respect to a sample having a width of 6. 50. 5mm, a thickness of 2. 00. 25mm and a length 7. 0-150mm based on ASTM-D- 2863, so as to measure the LOI. Observing a fracture surface of the same using an electron microscope performs an examination of morphology.

As the result, in the case of samples 1-7, the composition of the resin is comprised of only the waste materials (W-PE, W-EVA) to observe the flame retardancy and the foaming property. As shown in table 3, when W-PE/W-EVA is in an extent of 100-0/0-100 weight percent, the foaming is occurred at a temperature range of 140~195°C. At this time, it takes 25-30 minutes. The results have smooth surfaces. All of them uniformly have the closed-cell structure except the sample 3 using an inorganic chemical foaming agent. We can ascertain a fact that the samples have a foaming rate of about 320-355% in a radial direction.

As the result of the LOI test, the LOI is 28-35 which is fairly high in a practical aspect. Therefore, we can ascertain that the foam of the present invention is superior to the conventional foam.

Samples 8-13 are to observe an influence of V-PE on the foaming property.

When W-PE/W-EVA/V-PE is in an extent of 90-50/90-50/10-50 weight percent, the foaming is occurred at a temperature range of 140~193°C. At this time, it takes 25-28

minutes. The results have smooth surfaces. All of them uniformly have the closed-cell structure except the samples 10 and 11 that have a semi-open cell structure using DPT and AC-1000 as the organic chemical foaming agent. The samples have a foaming rate of 320-350%. They show a similar foaming property to the above samples. Therefore, in case the composition of the resin is comprised of only the waste materials (W-PE, W- EVA). It seems to have an excellent economic efficiency.

As the result of the LOI test, the LOI is 31-35 which is fairly high. Therefore, we can also ascertain that the foam of the present invention is superior to the conventional foam.

Samples 14-16 are to observe the foaming property and the flame retardancy when the resin is comprised of only the V-PE. The foaming is occurred at a temperature range of 130~175°C. At this time, it takes 30 minutes. The results have smooth surfaces.

All of them uniformly have the closed-cell structure. The samples have a foaming rate of 320-355.

As the result of the LOI test, the LOI is 37-38 which is fairly high. Therefore, we can ascertain that the foam of the present invention is superior to the conventional foam.

A change of the foaming rate among representative simples according to the composition rates of the resin and each addition agent is as follows.

The samples 1,4 and 7 are to observe a change in the foaming property and the flame retardancy according to increase in the content of the flame retardant with respect to the content of the resin. In case the content of the flame retardant with respect to the

content of the resin is gradually increased (sample 1esample 7), the LOI is also increased from 28 to 31. However, the foaming rate is gradually reduced from 355% to 320% in the radial direction. It seems that this phenomenon is resulted in the relative increase of the flame retardant with respect to the resin, i. e., the, reduction of the resin.

The samples 2,3 and 4 are to observe a change in the foaming property and the flame retardancy according to the composition of the resin when the content of the flame retardant with respect to the content of the resin is the same. In this case, the LOI of each sample is 31 and the same in all samples. The foaming rate is about 325-330% in the radial direction. There is only a slight difference in foaming rate. In the case of the sample 3, it has an open cell structure according to the use of the inorganic chemical foaming agent. Therefore, although the composition of the resin is comprised of only the W-PE or the W-EVA, the foaming rate is hardly changed. We can ascertain that the waste materials are preferably used for preparing the good foam having the excellent foaming property and flame retardancy.

The samples 12 and 13 are to observe a change in the foaming property and the flame retardancy according to the kind of the flame retardant. The sample 12 has a higher LOI of 34 than the sample 13 having an LOI of 33. The foaming rate of the sample 13 having 350% in the radial direction is higher than that of the sample 12 having 330%. Therefore, it seems that the reason why the LOI of the sample 12 is higher than that of sample 13 is caused by synergy effect according to the use of a phosphorous- based flame retardant, and the reason why the sample 12 has the lower foaming rate is

caused by increase in viscosity of a blended material according to the use of the phosphorous-based flame retardant.

Therefore, when the composition rate of the W-PENV-EVA/V-PE is in an extent of 0-100/0-100/0-100 weight percent and the blending process is carried out at a temperature of 110~138°C, it is clear that we can obtain an excellent foam having the foaming rate 3-3. 5 times in the radial direction, a smooth surface, a uniform cell structure including the closed-cell, the semi-open cell and the open cell, and a good modulus of elasticity.

In addition, we can ascertain the change of the flame retardancy and the foaming rate according to the composition of the resin, the composition of the resin and the flame retardant, and the mutual action of each addition agent. We can also ascertain that the composition of the resin considering the mutual action, the kind and the content of the addition agent (flame retardant, foaming agent and crosslink agent, and so force) with respect to the resin are important factors influenced on the flame retardancy and the foaming property (foaming rate and cell structure).

The result of the above embodiment is shown in a table 4 and each drawing, wherein the sample 1 is shown in Fig. 1, the sample 4 is in Fig. 2, the sample 7 is in Fig.

3, the sample 8 is in Fig. 4, the sample 11 is in Fig. 5, the sample 13 is in Fig. 6, and the sample 14 is in Fig. 7.

Table 3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 W-PE 100 90 70 50 30 10 0 90 70 50 W-EVA 0 10 30 50 70 90 100 90 70 50 W-RUBBER Resin GTR V-PE 10 30 50 10 30 50 100 100 100 NBR EPDM AI (OH) 3 90 120 110 100 120 120 130 140 60 20 40 140 140 180 180 180 Mg (OH) 2 20 20 30 40 20 20 30 20 80 120 100 20 20 Flame Magnesium 5 retardant silicate Zinc Borate Zinc Sulfide Sb203 10 10 10 10 10 10 10 10 10 10 15 15 Sb203 10 10 10 10 10 10 10 10 10 10 15 15 Sb205 10 10 10 10 H-201 5 5 10 5 H-205 10 10 10 10 TCEP10 10 50 Flame TCPP 50 retardant DPK 5 1 s , 5 50 Red 5 phosphorous Chlorinated paraffin Loess 10 10 10 10 20 30 15 15 Crosslink Perkadox 2 2. 5 2. 5 2. 5 5 5 3. 5 6 7 2. 5 2. 5 4 5 agent DCP 5 4 4 Organic ADCA 18 18 18 18 18 18 18 18 18 24 24 24 Organ ! C chemical AC- F°aagemnt9 agent DPT = = _= = = == 18 8 _ _ _ _ 18 10 foaming 100 Foaming agent DPT 18 8 argent Inorganic-- chemical Kycerol- 18 foaming 91 agent Foaming supplement Urea-based 1 2 1. 5 agent Internal release PE-Wax 4 2. 5 2. 5 agent External release Stearic acid 5 5 5 agent Stabilizer Ba-Zn based Plasticizer DOP Heat transfer ZnO 4 4 4 4 2 4 3 1 3 3 3 accelerator Table 4 Foaming Composition Sample Foaming Flame Sample Foaming Fiame Foaming W-P/W-E/W-R/GN- No. temperature/time Surface Cell structure retardantl LOI rate (%) P/N/E (WT%) (°C/min) others (PHR) Closed cell, 1 140193/25 355 Smooth 100/0/0/0/0/0/0 120/24. 0 28 uniform 2"330""90110/0/0/0/0/0 150/24. 5 31 Open celi 3"325"70/30/0/0/0/0/0 150/24. 5 31 uniform Closed cell, 4"330"50/50/0/0/0/0/0 150/24. 5 31 uniform 5 195/30320"30/70/0/0/0/0/0165/25. 030. 5 6140-190/27325""10/90/0/0/0/0/0180/23. 033. 5 7140-193/25320""0/100/0/0/0/0/0195/21. 533 8140-190/27330""90/0/0/0/10/0/0200/25. 035 "330""70/0/0/0/30/0/0 185/31. 0 34 Semi-open Semi-open 10 140o193/25 340"50/0/0/0/50/0/0 150/24. 5 31 cell, uniform i 1"320""0/90/0/0/10/0/0 150/20. 5 32 Closed cell, 12 140-190/28 330"0/70/0/0/30/0/0 195/26. 5 34 uniform 13 140o193/25 350""0/50/0/0/50/0/0 195/24. 0 33 14130-175/30355""0/0/0/0/100/0/0270/41. 037 15"340""0/0/0/0/100/0/0 260/38. 5 38 16"340""0/0/0/0/100/0/0260/38. 538

In the above table, the resin (W-P/W-E/W-R/G/V-P/N/E) means the W-PENV- EVA/W-RUBBER/GTR/V-PE/NBR/EPDM.

Second embodiment: blend of resin/addition agent [II] According to the result of the first embodiment, a proper composition and a processing condition are found out, such that, when the composition ofW-PE/W-EVA/V- PE is in an extent of 0-100/0-100/0-100 weight percent, the cell structure is uniform to have the closed cell, semi-open cell and open cell, the foaming rate is about 300-350% in the radial direction, and the LOI is in an extent of 28-38. On the basis of the result of the first embodiment, another experiment had been carried out using the W-RUBBER and the GTR while regulating the composition of the resin, the composition rate of the resin and the flame retardant, and the content of the other addition agent. The composition rate is shown in a table 5. The blending, extruding, cross-linking foaming processes and the examination of foaming property and .. morphology are performed in the same manner as those in the first embodiment.

As the result, in the case of samples 17-41, when the composition of W-PE/W- EVANV-RUBBER/GTRN-PENBR/EPDM is in an extent of 0-95/0-85/0-30/0-40/0-10 /0-30/0-50, the foaming is occurred at a temperature range of 140-193oC. At this time, we can ascertain a fact that it takes 22-30 minutes, and the results have smooth

surfaces, and the uniform closed-cell and semi open cell, and they also have a foaming rate of about 300-330% in a radial direction. And, as the result of the LOI test, the LOI is 31. 5-40 which is fairly high. Therefore, we can ascertain that the foam of the present invention is superior flame retardancy to the conventional foam.

A change of the foaming rate among representative simples according to the composition rates of the resin and each addition agent is as follows.

The samples 17,18 and 25 are to observe a change in the foaming property and the flame retardancy according to a change in the content of W-RUBBER when W-PE, W-EVA, W-RUBBER are used as the resin. We ascertain that the LOI is reduced from 37 to 31.5 according to reduction in the content of flame retardant with respect to the resin (sample 17o18<25). However, in the foaming rate, the samples 17 and 18 have the same foaming rate of 310%, and the foaming rate of the sample 25 is increased to 330%. It seems that this phenomenon is resulted in the relative increase of the flame retardant with respect to the resin, i. e. , the relative reduction of the content of the resin. Therefore, preferred foaming property having the foaming rate of 300% or more can be obtained within a content of the W-RUBBER of 30 weight percent.

The samples 12 and 13 are to observe a change in the foaming property and the flame retardancy according to the kind of the flame retardant. The sample 12 has a higher LOI of 34 than the sample 13 having an LOI of 33. The foaming rate of the sample 13 having 350% in the radial direction is higher than that of the sample 12 having

330%. Therefore, it seems that the reason why the LOI of the sample 12 is higher than that of sample 13 is caused by synergy effect according to the use of a phosphorous- based flame retardant, and the reason why the sample 12 has the lower foaming rate is caused by increase in viscosity of a blended material according to the use of the phosphorous-based flame retardant.

The samples 29,30, 31 are to observe the change in the foaming property and the flame retardancy when the content of the flame retardant with respect to the content of the resin is the same. Each sample has a similar foaming rate of 300%, 300% and 305%, but there is a difference in the LOI of 34,36 and 36. 5. It seems that this is caused by synergy effect resulted in the relative increase of the content of H-201 as one of the phosphorous-based flame retardant. The sample 31, which uses DPT and AC-1000 as the organic chemical foaming agent, has the same semi-open cell as that in the first embodiment.

The samples 19,20 and 26 are to observe the foaming property and the flame retardancy according to a change in the content of the flame retardant with respect to the content of the resin. The foaming rate of each sample is 300%, 310%, 330%, and the LOI is 37,36 and 33. In the case of the samples 19 and 20, although the contents of the resin and the flame retardant are the same, there is a difference in the foaming rate and the LOI. It seems that this is caused by a difference in the kind and the content of the flame retardant. In the case of the sample 26, though the content of the flame retardant with respect to the content of the resin is higher than those of the samples 19 and 20, a

difference in the LOI is not much. This is caused by the difference in the kind and the content of the flame retardant. In other words, the DPK used in the samples 19 and 20 takes an important part as a plasticizer rather than the flame retardant. Further, in case the content of the GTR is within 40 weight percent, we can obtain a preferred foam having a foaming rate of 300% or more.

The samples 29-36 are to observe the change of the foaming property and the flame retardancy when 30 weight percent or more of GTR is used. When 0-10 weight percent of V-PE, 0-10 weight percent of NBR and 0-10 weight percent of EPDM are provided, we can obtain the preferred foaming rate of 300-305% and the very high LOI of 33-37.

The samples 37 and 38 are to observe the change of the foaming property and the flame retardancy according to the change in the content and the kinds of the flame retardant with respect to the resin and the content of the other addition agent. The sample 38 has a much higher LOI of 37.5 than the sample 37 having the LOI of 33.

Further, the sample 38 has a similar foaming rate of 300% to the sample 37 having a foaming rate of 305%. Therefore, it seems that the reason why the sample 37 having a little low content of the flame retardant with respect to the resin has a very lower LOI than the sample 38 is resulted in an influence of the plasticizer (DOP).

According to the experiment result, as described above, when the composition rate of W-PE/W-EVA/W-RUBBER/GRT/V-PE/NBR/EPDM is in an extent of 0-95/0-85/0-30/0-40/0-10/0-30/0-50 weight percent, the blending process is carried

out at a temperature of 110-138°C. We can obtain an excellent foam having the foaming rate 3-3. 5 times in the radial direction, a smooth surface, a uniform cell structure including the closed-cell, the semi-open cell and the open cell, a good modulus of elasticity, and an LOI of 31. 5-40, thereby showing the excellent flame retardancy and the foaming property.

In addition, we can ascertain the change of the flame retardancy and the foaming rate according to the composition of the resin, the composition of the resin and the flame retardant, and the mutual action of each addition agent. We can also ascertain that the composition of the resin considering the mutual action, the kind and the content of the addition agent (flame retardant, foaming agent and crosslink agent, and so force) with respect to the resin are important factors influenced on the flame retardancy and the foaming property (foaming rate and cell structure).

The result of the above embodiment is shown in a table 6 and each drawing, wherein the sample 15 is shown in Fig. 8, the sample 17 is in Fig. 9, the sample 23 is in Fig. 10, the sample 28 is in Fig. 11, the sample 29 is in Fig. 12, the sample 32 is in Fig.

13, the sample 38 is in Fig. 14, the sample 39 is in Fig. 16 and the sample 40 is in Fig.

17. The dispersion level of the conventional flame retarding'polyolefin foam and the addition agent is shown in Fig. 17.

Table 5 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Resin W-PE 95 80 90 60 85 75 60 60 65 W-EVA 70 60 85 60 65 W-RUBBER 5 20 5 5 20 10 30 5 10 GTR 10 40 10 20 20 30 40 10 30 30 30 V-PE 5 5 NBR EPDM AI (OH) 3 150 180 120 120 120 120 100 100 120 110 100 100 120 120 Mg (OH) 2 50 20 20 20 20 20 20 20 20 20 20 20 20 20 Magnesium silicate 10 Zinc Borate 5 10 30 50 10 Zinc Sulfide Sb203 10 10 10 10 10 10 10 10 Sb20s1010101010 Clame retardant H-201 30 30 10 5 10 10 10 retardant H-205 30 50 5 5 10 TCEP 30 10 10 TCPP 30 DPK 10 10 10 10 10 20 5 10 5 10 10 10 10 Red phosphorous 10 10 10 10 10 Chlorinated paraffin 30 30 Loess 30 10 10 10 10 10 20 10 Crosslink Perkadox 4 7 5 6 3. 5 5 5 5 4 5 7 5 5 5 agent Organic ADCA 18 18 18 18 18 18 18 18 18 18 18 18 18 chemical AC- foaming 100 Foaming agent DPT agent Inorganic chemical Kycer 18 18 foaming ol-91 agent Foaming suppleme Urea-based 1 1 1 1 1 1. 5 1 1. 5 nt agent Internal release PE-Wax 5 10 4 agent External release Stearic acid 4 10 agent Stabilizer Ba-Zn based 1 1 1 2. 5 1 2. 5 Plasticizer DOP 5 5 Heat transfer ZnO 4 2 5 1 2. 5 2. 5 2 3 1 1. 5 3 2 accelerator 31 32 33'34 35 36 37 38 39 40 41 W-PE 50 50 50 60 30 20 30 40 W-EVA 40 50 50 30 30 20 40 40 W-RUBBER 10 10 10 Resin GTR 40 40 40 40 45 40 10 10 10 V-PE 5 10 NBR 5 10 10 10 30 EPDM 5 10 10 50 20 AI (OH) 3 90 120 100 80 90 80 240 180 250 200 Mg (OH) 2 50 20 40 60 50 60 Magnesium silicate 20 Zinc Borate 10 10 10 Zinc Sulfide 50 Sb203 10 10 10 10 10 10 10 30 10 10 Sb205 30 Flame H-201 20 20 5 5 20 5 retardant H-205 10 10 10 TCEP 5 10 10 5 TCPP DPK 5 5 5 5 5 5 40 30 20 Red phosphorous 10 Chlorinated 50 paraffin Loess 20 20 10 10 20 10 10 Crosslink agent Perkadox 6 7 5 4 6 4 21 22 22 25 23 agent ADO Organic A 18 18 18 18 18 24 32 40 24 24 chemical AC- foaming 100 10 F°aagemnt9 agent DPT a <= == === = Foaming agent agent Inorganic chemical Kycer foaming ol-91 agent Foaming supplement Urea-based 1 1 2 agent Internal release PE-Wax 5 1 5 5 5 5 agent External Stearic acid 5 2. 5 5 5 5 5 release agent Stabilizer Ba-Zn based 1. 5 2 2 2. 5 1. 5 2. 5 Plasticizer DOP 5 5 10 10 5 1050 Heat transfer ZnO 1 1 2 4 1 4 3 4 4 3 4 accelerator Table 6 Foaming Composition Sample Foaming Flame Foaming Cull W-P/W-E/W-R/G ! V- No. temperature/Surface retardant/LOI rate (%) structure P/N/E (WT%) time (°C/min) others (PHR) Closed 17 140190/30 310 Smooth cell, 95/0/5/0/0/0/0 230/36. 0 37 uniform 18 140o193/28 310""80/0/20/0/0/0/0 220/26. 0 35 19"300""90/0/0/10/0/0/0 230/26. 0 37 20"310""60/Ol0/40/0/0/0 230/24. 0 36 21140-)-185/22300""85/0/5/10/0/0/0230/37. 5 37 22140-190/25300""75/0/5/20/0/0/0230/38. 0 37. 5 23"320""60/0/20/20/0/0/0 185/27. 5 33 24"315""60/0/10/30/0/0/0 185/27. 5 33 25"330""0/70/30/0/0/0/0 165/24. 0 31. 5 26 330 0/60/0/40/0/0/0 165/33. 5 33 27"320""0/85/5/10/0/0/0190/27. 533 28"315""0/60/10/30/0/0/0 190/25. 5 33 29"300""65/0/0/30/5/0/0 210/34. 5 34 30"300""0/65/0/30/5/0/0210/26. 536 Semi- 31"305"open cell, 50/0/0/40/5/5/0 210/31. 5 36. 5 uniform Closed 32 305 cell, 0/40/0/40/10110/0 215/34. 0 37 uniform 33 300 50/0/0/40/0/10/0 200/37. 0 34. 5 34 140--187/30'300""0/50/0/40/6/10/0 180/38. 5 33 35 185/30300""50/0/0/45/0/0/5210/41. 536 36 1409185/30 300""o/50/0/40/0/0/10 180/38. 5 33 37 1409175/30 305""60/30/10/o/o/0/10 260/101. 5 33 38"300""30/30/0/10/0/30/0 270/68. 5 37. 5 39"300""20/20/0/10/0/0/50 270/76. 0 37 40"310""30/40/10/0/0/0/20290/62. 040 41"305""40/40/10/10/0/0/0280/61. 039. 5

in the above table, the resin (W-P/W-E/W-R/G/V-P/N/E) means the W-PE/W- EVA/W-RUBBER/GTRN-PE/NBR/EPDM.

INDUSTRIAL APPLICABILITY ! As described above, the present invention is composition which uses waste polyethylene (W-PE), waste ethylene-vinyl copolymer (W-EVA), waste rubber, or ground tire rubber (GTR) as a base resin, if necessary, blends a minute amount of virgin polyethylene, nitrile rubber and ethylene-propylene copolymer (EPDM) and then adds an inorganic-based and phosphorus-based flame retarding agent, foaming agent, crosslink agent or other addition agent, thereby efficiently recycling the waste plastic, the waste rubber and the ground tire rubber and, at the same time, providing products which are environment-friendly and have a high stability, mechanical and physical property, particularly, a high flame retardancy and economic efficiency,