WO2004096900A1

WO2004096900A1 - Foaming plastic body which has excellent incombustibility

Info

Publication number: WO2004096900A1
Application number: PCT/KR2004/000970
Authority: WO
Inventors: Gi-Hong Yu; Hong-Jae Lee
Original assignee: Kyungdong Ceratech Co., Ltd.
Priority date: 2003-04-30
Filing date: 2004-04-28
Publication date: 2004-11-11
Also published as: CN1798799A; CN100484988C; JP2006525406A

Abstract

The conventional foam plastics formed by expansion and molding of a flame retardant resin are only self-extinguishable, that is, when they come into contact with flame and released from the flame, they are voluntarily extinguished and are helpless at fire. Also, the conventional foam plastics have a limitation in that the content of an organic materials to increase fire resistance of the foam plastics is limited. In order to solve the problems, the foam plastic body with excellent incombustibility according to the present invention is formed to have an incombustible diaphragm by introducing an organic incombustible diaphragm forming material or an inorganic incombustible diaphragm-forming agent during the expansion molding process of a expandable plastic resin or the fusion molding process of expanded beads and carrying out the expansion and fusion by means of a heating source. Therefore, according to the present invention, there is provided a foam plastic body with excellent incombustibility while maintaining impact absorption, moldability and heat insulation which are advantageous properties of foam plastics, prepared by introducing an inorganic or organic incombustible diaphragm-forming agent.

Description

FOAMING PLASTIC BODY WHICH HAS EXCELLENT INCOMBUSTIBILITY

Technical Field

The present invention relates to a foam plastic body with excellent incombustibility.

More particularly, the present invention relates to a foam plastic body with excellent incombustibility, which is formed to have an incombustible diaphragm by introducing an organic incombustible diaphragm forming material or an inorganic incombustible diaphragm-forming agent during the expansion molding process of a expandable plastic resin or the fusion molding process of expanded beads and carrying out the expansion and fusion by means of a heating source.

Background Art

The foam plastics have more excellent impact absorption, easier molding processability, lower thermal conductivity and better heat insulation, as compared to inorganic substances and thus, are used as construction insulation materials, shock absorbers for packing, cold storage containers, engineering and construction elements, materials for agriculture and gardening. However, since the conventional foam plastics have a low softening point and melting point, they melt at a relatively low temperature to be deformed and cannot maintain their shapes.

Also, the plastics have a fundamental problem in that when flame is ignited by external ignition factor such as contact with flame, they act as energy to help combustion by themselves and ^'spread fire.

For such problem, they are gradually limited in use to various fields such as use as a construction element.

As a technique to supplement the foregoing problems, a resin is provided with flame retardancy by addition flame retarding methods comprising adding a flame retardant halogen, antimony, phosphorus or nitrogen containing compounds and a flame retardant aid to a resin and polymerization flame retarding methods comprising using a specific monomer containing a flame retardant atom during polymerization to prepare a resin and then expanded and molded to produce a foam plastic with flame retardancy.

However, the polymerization flame retarding methods, though having excellent flame retardancy effect, have defects of high production cost and long production time since the regent acts in the form of a copolymer. Therefore, generally, the addition flame retarding methods using an inorganic substance „ which is cheap, shows synergic effect with a halogen compound and serves as a filler and the addition flame retarding methods using an organic substance which is readily compounded with a polymer are preferred. However, at present, the foam plastics formed by expansion and molding while using such flame retardant are only self- extinguishable, that is, when they come into contact with flame and released from the flame, they are voluntarily extinguished. Therefore, they do not satisfy even the lowest grade of the provision of KS F 227 (Test Method for flame retardancy of interior material and structure of construction) and are helpless at fire.

In order to solve these problems, an incombustible organic foam body (Korean Patent Application No. 10-2003-0024544, filed at April 18, 2003) was proposed by the present inventors, in which an incombustible inorganic adhesive is introduced into the expansion molding process of an expandable resin such as expandable polystyrene (EPS), expandable polyethylene (EPE), expandable polypropylene (EPP) and expandable polyurethane (EPU) or the fusion molding process of the expanded resin to prepare the foam body.

However, the above technique has a limitation since it includes addition of an inorganic adhesive to an expandable resin and consequently, the content of an organic materials to increase fire resistance of the foam plastics is limited.

Disclosure of Invention

Technical Problem

The present invention has been made to solve the foregoing problems and it is an object of the present invention to provide a foam plastic body with excellent incombustibility while maintaining impact absorption, moldability and heat insulation which are advantageous properties of foam plastics, prepared by introducing an incombustible diaphragm-forming agent.

Also, it is a further object to provide a foam plastic body with excellent incombustibility by further introducing an additive such as a thermal resistance enhancer or a blowing agent along with an incombustible diaphragm-forming agent.

Technical Solution The present invention is directed to a foam plastic body with excellent incombustibility.

According to the present invention, an inorganic or organic incombustible diaphragm-forming agent is added to a expandable resin such as expandable polystyrene (EPS), expandable polyethylene (EPE), expandable polypropylene (EPP), expandable polyurethane (EPU) and the like during the expansion molding process of the expandable resin or the fusion molding process of the expanded product to prepare a foam plastic body with excellent incombustibility. The diaphragm-forming agent refers to a substance which may form a diaphragm acting as a screen against a burning part during combustion.

Also, the organic diaphragm-forming agent refers to a thermosetting resin which may form a large amount of char upon carbonization by flame.

Concretely explaining the present invention by taking expandable polystyrene as an example, an organic or inorganic diaphragm-forming agent is added to resin pellets or expanded beads, and the fusion is carried out by means of a heating source such as steam, microwave and the like to prepare an incombustible foam plastic body having foam plastics existing between numerous incombustible diaphragms.

The method for introducing the organic or inorganic diaphragm-forming agent includes impregnation application or compounding and injection into a mold.

The organic or inorganic incombustible diaphragm- forming agent, introduced by one of the above-listed method, is embedded in the plastic resin, or applied on the surface of the resin to form a molded body having numerous incombustible diaphragms.

The incombustible diaphragms formed in a layered structure may maintain the cellular diaphragm configuration acting as a flame resistant barrier to prevent the propagation of flame, even when the plastic resin melts by contact with flame.

Further, a part having pores formed by melt of the plastic resin builds a heat insulation layer of a honeycomb type cellular structure and acts as a barrier to inhibit transmission of heat, thereby providing excellent flame retardancy and thermal resistance.

The incombustible diaphragm-forming agent is classified into an inorganic type and an organic type to high strength char.

Examples of the inorganic type include silicates such as sodium silicate, potassium silicate and lithium silicate or modified silicates, phosphates such as phosphoric acid, sodium phosphate and aluminum phosphate, sol type compounds such as silica sol and alumina sol, boric acid, borax, perborate, metaborate, borohydride, borate, and low melting frits such as low melting glass frit (PbO-Si0₂-B₂0₄ type).

Also, examples of the organic type include melamine resins, urea resins, phenol resins, furan resins, epoxy resins, unsaturated polyester resins, resorcin resins, dicyandiamides, polyols, chlorinated paraffins, dipentaerythritol (DPE), and derivatives thereof.

Meanwhile, in order to increase the effect of the present invention, various additives such as an adhesion aid or thermal resistance enhancer may be further included.

Concretely, an adhesion aid may be added to the organic or inorganic diaphragm-forming agent prior to being used in the preparation of the plastic body according to the present invention so that the organic or inorganic diaphragm-forming agent in the liquid state is well penetrated into the plastic reins in the solid state.

In this case, if a surfactant is used as an adhesion aid, the diaphragm-forming agent in the liquid state may be well penetrated into the plastic resin in the solid state while if a silane coupling agent is used, the adhesion of the two materials can be secured upon drying after the penetration of the diaphragm-forming agent.

Also, sodium silicofluoride may be selectively used to improve durability and waterproofness of the diaphragm-forming agent . According to the present invention, a thermal resistance enhancer such as titanium oxide, mica, carbon, silica powder and ettringite compounds may be further included.

The thermal resistance enhancer as described above acts as a flame retardant aid to improve flame retardant properties by intercept of radiant heat, supplement of thermal resistance and release of crystal water at a low temperature and prevents deformation by heat at a relatively low temperature range.

Also, according to the present invention, a blowing agent may be further included. As described above, the incombustible diaphragms of the honeycomb structure with a certain depth formed by the incombustible diaphragm-forming agent prevent propagation of flame when the foam plastic body contacts with flame and the blowing agent forms a thick flame protecting membrane and a heat insulation layer by further expand the incombustible diaphragms upon contact with flame, thereby reinforcing the effect of such incombustible diaphragms.

Examples of the blowing agent include mono-ammonium phosphate, di-ammonium phosphate and potassium tripolyphosphate . In addition, according to the present invention, a flame retardant may be further included.

The flame retardant acts to prevent propagation of flame by the melt of the foam plastic or the organic diaphragm-forming agent when the plastic body according to the present invention contacts with flame.

Examples of the flame retardant include phosphorus compounds, halogen compounds, aluminum hydroxide, magnesium hydroxide, antimony compounds and zinc borate.

Advantageous Effect According to the present invention, there is provided a foam plastic body with excellent incombustibility while maintaining impact absorption, moldability and heat insulation which are advantageous properties of foam plastics, prepared by introducing an organic or inorganic diaphragm- forming agent to a expandable resin.

Also, there is provided a foam plastic body with excellent incombustibility prepared by further introducing an additive such as a thermal resistance enhancer and a blowing agent along with an incombustible diaphragm-forming agent.

Best Mode Expandable polystyrene (EPS, LG Chem. , Ltd., R320, flame retardant) pellets were expanded by steam to form expanded beads . The expanded beads were aged for 24 hours to substitute the blowing gas contained in the cells with air so that the cells had elasticity, that is the force of restitution.

Also, the beads were impregnated with a 40 Baume sodium silicate solution, as a flame retardant inorganic adhesive, with a small amount of a surfactant and a silane coupling agent added, put into a mold of 300 X 300 mm at a dry density of 30 kg/m³ and molded by introducing steam. The molded product was dried to prepare an incombustible foam plastic body of 300 x 300 x 50 mm.

Mode for Carrying Out the Invention

The present invention will be explained in further detail through the following Examples and Comparative examples .

However, the examples are for illustration only and the present invention is not limited thereto. <Example 1>

Expandable polystyrene (EPS, LG Chem. , Ltd., R320, flame retardant) pellets were expanded by steam to form expanded beads .

The expanded beads were aged for 24 hours to substitute the blowing gas contained in the cells with air so that the cells had elasticity, that is the force of restitution.

Also, the beads were impregnated with a 40 Baume sodium silicate solution, as a flame retardant inorganic adhesive, with a small amount of a surfactant and a silane coupling agent added, put into a mold of 300 X 300 mm at a dry density of 30 kg/m³ and molded by introducing steam. The molded product was dried to prepare an incombustible foam plastic body of 300 x 300 x 50 mm. <Example 2> An incombustible foam plastic body of 300 x 300 x 50 mm was prepared by following the procedures of Example 1, except that sodium silicate was substituted with mono aluminium phosphate, A1₂0₃.₃(P₂0₅) .6 (H₂0) ) . <Example 3> An incombustible foam plastic body of 300 x 300 x 50 mm was prepared by following the procedures of Example 1, except that phosphoric acid was added to sodium silicate in 3:1 weight ratio of phosphoric acid to sodium silicate. <Example 4> An incombustible foam plastic body of 300 x 300 x 50 mm was prepared by following the procedures of Example 1, except that boric acid was added to sodium silicate in a 5:1 weight ratio of boric acid to sodium silicate. <Example 5>

An incombustible foam plastic body of 300 x 300 x 50 mm was prepared by following the procedures of Example 1, except that melamine resin and mono-ammonium phosphate were added to sodium silicate in a 5:1 weight ratio to sodium silicate, respectively.

An incombustible foam plastic body of 300 x 300 x 50 mm was prepared by following the procedures of Example 1, except that phosphoric acid in a 3:1 weight ratio to sodium silicate, boric acid in a 5:1 weight ratio to sodium silicate, melamine resin in a 5:1 weight ratio to sodium silicate and mono- ammonium phosphate in a 5:1 weight ratio to sodium silicate were added to sodium silicate. <Example 7>

An incombustible foam plastic body of 300 x 300 x 50 mm was prepared by following the procedures of Example 1, except that the expandable polystyrene was substituted with waste expandable polystyrene powder (particle size of 2 to 0.5 mm). <Example 8>

An incombustible foam plastic body of 300 x 300 x 50 mm was prepared by following the procedures of Example 1, except that the expandable polystyrene pellets were substituted with expandable propylene (EPP, Hanwha L&C Corp., 30 expansion magnification, more than 80 %) pellets.

An incombustible foam plastic body of 300 x 300 x 50 mm was prepared by following the procedures of Example 1, except that sodium silicate was substituted with a boric acid solution.

An incombustible foam plastic body of 300 x 300 x 50 mm was prepared by following the procedures of Example 1, except that sodium silicate was substituted with melamine resin.

An incombustible foam plastic body of 300 x 300 x 50 mm was prepared by following the procedures of Example 1, except that sodium silicate was substituted with phenol resin.

An incombustible foam plastic body of 300 x 300 x 50 mm was prepared by following the procedures of Example 1, except that sodium silicate was substituted with melamine resin with a halogen-based flame retardant added.

In order to confirm the effect of the present invention, a foam plastic body was prepared by the following conventional method. <Comparative example 1>

Expandable polystyrene (EPS, LG Chem. , Ltd., R320, normal) pellets were expanded by steam to form expanded beads.

The expanded beads were aged for 24 hours, put into a mold of 300 X 300 mm at a dry density of 30 kg/m³ and molded by introducing steam. The molded product was dried to prepare an incombustible foam plastic body of 300 x 300 x 50 mm.

An incombustible foam plastic body of 300 x 300 x 50 mm was prepared by following the procedures of Comparative example 1, except that the expandable polystyrene was substituted with flame retardant-treated expandable polystyrene (EPS, LG Chem., Ltd., R320, flame retardant) pellets . <Comparative example 3>

An incombustible foam plastic body of 300 x 300 x 50 mm was prepared by following the procedures of Comparative example 1, except that the expandable polystyrene were substituted with expandable propylene (EPP, Hanwha L&C Corp., 30 expansion magnification) pellets.

The specimens prepared in Examples 1 to 12 and Comparative examples 1 to 3 were left in a well-ventilated room for 48 hours and dried at 40 + 5^°C for 120 hours. Then, they were measured for thermal resistance and flame retardancy.

The thermal resistance was evaluated according to JIS K 6767 and the result is shown in Table 1. The flame retardancy was measured through differential thermal analysis (DTD) to know a melt and decomposition degree by measuring a endothermic or exothermic state and weight change, thermogravimetry (TG) or differential scanning calorimetry (DSC) to know a melt and decomposition degree by measuring a calorie change according to temperature. Here, in order to determine the resistance to flame, the surface of each specimen was contacted with a flame (length: 50 mm, width: 7 mm or more) of a candle for flower gardens (wick length: about 10 mm, diameter: about 20 mm) for 10 minutes. After the flame was removed, the formation of fire-resistant diaphragm was observed and the result is shown in Table 2.

In Table 1, Example 8 and Comparative example 3 which cannot be compared to the present invention are omitted.

Table 1

Thermal deformation according to temperature (length %)

Table 2 Thermal Performance According To Temperature (cumulative lg. loss (wt%))

From the results of Table 1 and Table 2, it was noted that the foam body which had been treated with a diaphragm- forming agent had excellent incombustibility and flame resistance. Particularly, Examples 10, 11 and 12, in which an organic diaphragm-forming agent was added, formed a non- contractible diaphragm by the formation of char and had excellent incombustibility, though they showed a Ig.loss similar to those of Comparative examples.

Claims

What Is Claimed Is:

1. A foam plastic body with excellent incombustibility, which is formed ^■ to have an incombustible diaphragm by introducing an organic incombustible diaphragm forming material or an inorganic incombustible diaphragm-forming agent during the expansion molding process of a expandable plastic resin or the fusion molding process of expanded beads and carrying out the expansion and fusion by means of a heating source.

2. A foam plastic body with excellent incombustibility, which is formed to have an incombustible diaphragm by introducing an organic incombustible diaphragm forming material and an inorganic incombustible diaphragm-forming agent during the expansion molding process of a expandable plastic resin or the fusion molding process of expanded beads and carrying out the expansion and fusion by means of a heating source.

3. The foam plastic body according to claim 1 or 2 , in which the organic incombustible diaphragm-forming agent is at least one selected from melamine resins, urea resins, phenol resins, furan resins, epoxy resins, unsaturated polyester resins, resorcin resins, dicyandiamides, polyols, chlorinated paraffins, dipentaerythritol, and derivatives thereof and the inorganic incombustible diaphragm-forming agent is at least one selected from silicates such as sodium silicate, potassium silicate and lithium silicate or modified silicates, phosphates such as phosphoric acid, sodium phosphate and aluminum phosphate, sol type compounds such as silica sol and alumina sol, boric acid, borax, perborate, metaborate, borohydride, borate, and low melting frits such as low melting glass frit (PbO-Si0₂-B₂0₄ type).

4. The foam plastic body according to claim 1 or 2, in which the organic incombustible diaphragm forming material and the inorganic incombustible diaphragm-forming agent are at least one selected from an adhesion aid, a thermal resistance enhancer, a blowing agent and a flame retardant.

5. The foam plastic body according to claim 4, in which the adhesion aid is at least one selected from a surfactant, silane coupling agent and sodium silicofluoride .

6. The foam plastic body according to claim 4, in which the thermal resistance enhancer is at least one selected from titanium oxide, mica, carbon, silica powder and ettringite compounds .

7. The foam plastic body according to claim .4, in which the blowing agent is at least one selected from mono-ammonium phosphate, di-ammonium phosphate and potassium tripolyphosphate .

8. The foam plastic body according to claim 4, in which the flame retardant is at least one selected from phosphorus compounds, halogen compounds, aluminum hydroxide, magnesium hydroxide, antimony compounds and zinc borate .