WO2003048242A1

WO2003048242A1 - Flame retarding foam composition utilizing waste material and fabricating method thereof

Info

Publication number: WO2003048242A1
Application number: PCT/KR2002/002281
Authority: WO
Inventors: Byung-Wook Jo; Sung-Chul Moon; Jae-Gon Choi
Original assignee: Ehwa Chemical Co., Ltd.
Priority date: 2001-12-04
Filing date: 2002-12-04
Publication date: 2003-06-12
Also published as: KR100404768B1; AU2002365856A1; KR20030046551A

Abstract

There is disclosed a flame retarding foam composition which uses waste polyethylene (W-PE), 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.

Description

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 (W_TPE), 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 the* 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).

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 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.

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,

of Sb₂O_3l 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

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.

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

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-

mentioned components is analyzed by each part of the tire in each case of the

automobile and the truck.

Table 2

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 + O₂ (reducing a concentration of active OX and XOH and

stopping chain reaction, thereby obtaining the flame retarding effect)

X- + O- + M — XO- + M-

χ₂ + o- --- XO- + X- (obtaining an effect of generating noncombustible gas

during decomposition and blocking generation of O₂)

O- + OX — » 0₂ + 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 O- 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 H₂O, CO₂, SO₂, 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 - -» AI₂O₃ +3H₂O - 298KJ/mol

Mg(OH)₂ + heating -— > MgO + H₂O -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, SbCI₃ 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

Sb₂O₃ + 2HCI (maintained at ~250°C) — - 2SbOCI +H₂0

5SCOCI (maintained at 245-280°C) — > Sb₄O₅CI + SbCI₃8 4Sb 0₅CI₂ (maintained at 410~475°C) — -> 5Sb₃O₄CI + SbCI₃8

3Sb304CI (maintained at 475~565°C) --- » 4Sb₂O₃ + SbCI₃8

Sb₂O₃(S) (maintained at 685°C) -- Sb₂O₃(l)

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

2H₃RO₄ — -^→ H₄E₂O₇ pyrophosphoric acid

H₃RO₄ — -^-> HFO 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, Sb₂O₃, Sb₂O , 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 (AI₂θ₃X2SiO₂XnH₂O) and designates a component such as montmorilionite

(AI₂O₃X4Si0₂X6H₂O), pyrophillite (AI₂O₃X4SiO₂XH₂O), illite {KAI₂(OH)₂[AISi3(O,OH)₁₀]},

talc(3MgOX4SiO₂XH₂O) 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 (HAAKE). 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 6.5±0.5mm, a thickness of 2.0+0.25mm 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 1-»sample 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-PE/W-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

Table 4

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/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 of W-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-

EVA/W-RUBBER/GTR/V-PE/VBR/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 140~193°C. 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 17-»18- 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

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

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.

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

Table 6

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/GTR/V-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,

Claims

CLAIMS:

1. 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 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.

2. The composition of claim 1 , wherein the addition agent further comprises

one or more agent selected from 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.

3. The composition of claim 1 or 2, wherein the waste polyethylene resin

has a melting point of 100~130°C, and the waste ethylene-vinyl copolymer contains vinyl

acetate of 10-50%.

4. The composition of claim 1 or 2, wherein the nitrile rubber contains 8-34

weight percent of acrylonitrile

5. The composition of claim 1 or 2, wherein the ethylene-propylene

copolymer contains 4.5-8 weight percent of ENB.

6. A flame retarding foam composition, using waste material, fabricated by

mixing the component of claim 1 or 2 at a temperature of 110~138°C, and then extruding, pressing or injecting.