WO2009133975A1

WO2009133975A1 - Flame-retardant bead composition for producing flame-retardant expanded polystyrene foam and method of producing flame-retardant beads using the same

Info

Publication number: WO2009133975A1
Application number: PCT/KR2008/002458
Authority: WO
Inventors: Hyun-Kwang Kim; Tae-Yul Kwon; In-Ki Yun
Original assignee: Hyun-Kwang Kim; Tae-Yul Kwon; In-Ki Yun
Priority date: 2008-04-30
Filing date: 2008-04-30
Publication date: 2009-11-05

Abstract

Disclosed herein are a composition for producing flame-retardant expanded polystyrene foam and a method for producing flame-retardant beads using the same, in which a self-extinguishing flame-retardant composition is introduced into expanded polystyrene foam particles, such that self-extinguishing flame-retardant polystyrene foam of flame retardancy grade 3 can be produced. Specifically, the composition for producing flame-retardant expanded polystyrene foam is produced using a method comprising: a first mixing step (Sl) of mixing silicic acid, a surfactant and neozapon powder to obtain a first mixture (Pl); a second mixing step (S2) of adding the first mixture (Pl) and liquid glass to expandable polystyrene (EPS) as a raw material for producing expanded polystyrene foam to obtain a second mixture (P2); and a third mixing step (S3) of adding ammonium phosphate and a surfactant to the second mixture (P2) to obtain a third mixture (P3). The composition is pre-expanded by heating at about 90-120 ? to obtain beads having the flame-retardant material introduced therein. The beads can be compression-molded to obtain flame-retardant expanded polystyrene foam. The flame-retardant material in place of air is introduced into cells formed in the beads forming expanded polystyrene foam. Thus, when the polystyrene foam catches fire, it is melted, while flame-retardant gas is generated from the inside of the polystyrene foam to block oxygen, whereby the polystyrene foam shows flame retardant properties. In addition, it is possible to obtain flame-retardant polystyrene foam, which can be recycled without deteriorating thermal insulation, shock-absorbing and processability properties, which are the characteristic properties of polystyrene foam.

Description

[DESCRIPTION] [Invention Title]

FLAME-RETARDANT BEAD COMPOSITION FOR PRODUCING FLAME-RETARDANT EXPANDED POLYSTYRENE FOAM AND METHOD OF PRODUCING FLAME-RETARDANT BEADS USING THE SAME

[Technical Field]

<i> The present invention relates to a flame-retardant bead composition for producing flame-retardant expanded polystyrene foam and a method of producing flame-retardant beads using the same, in which a self-extinguishing flame- retardant composition is introduced into beads, produced by pre-expanding a mixture of expandable polystyrene particles with a flame-retardant material, such that self-extinguishing flame-retardant polystyrene foam can be produced using the beads.

<2>

[Background Art]

<3> In general, expandable polystyrene has excellent thermal insulation, shock-absorbing and processability properties, and thus is widely used in various industrial applications. Particularly, it is mainly used as packaging materials for protecting products, or thermal insulation materials or sound-absorbing materials for buildings.

<4> However, the polystyrene foam has problems in that, because it has very low heat resistance, it is burned by heat, when it catches fire, to cause the spread of fire, and it generates noxious gases harmful to the human body to cause human casualties.

<5> For this reason, in attempts to solve the above-described problems occurring in the prior art, studies on flame-retardant expanded polystyrene foam have recently been actively conducted. Examples of the expanded polystyrene foam include products, obtained by adding porous mineral particles to beads for producing molded polystyrene foam, and compression- molding the mixture, products obtained by applying a flame-retardant sheet or a flame retardant material to the outside of molded polystyrene foam, and products obtained by injecting a flame retardant material into completed expanded polystyrene foam so as to show flame-retardant effects. However, the polystyrene foam products, obtained by applying porous mineral particles to the outside of beads and compression-molding the beads, have excellent flame-retardant properties, but have problems in that processability, thermal insulation and moldability properties, which are the excellent properties of polystyrene foam, are reduced, and the produced polystyrene foam is difficult to handle, because it is heavy and is easily breaks. In addition, there are problems in that the production thereof is reduced, and when water penetrates the completed product, the adhesion of the flame retardant is reduced. Meanwhile, the polystyrene foam products, obtained by applying a flame- retardant sheet or a flame retardant to the outside of polystyrene foam, have problems in that, the flame retardant must be applied to the surface of polystyrene foam and dried, much manpower and time are required, leading to a reduction in productivity, large-sized production systems are added to increase the price of the produced polystyrene foam, and the flame retardant is not present in the inner part and on the cut surface of polystyrene foam, such that the inner part of polystyrene foam is burned as the fire caught on the foam progresses. Meanwhile, the polystyrene foam products, obtained by injecting a flame retardant material into molded expanded polystyrene foam using a plurality of syringe needles, have problems in that the flame retardant material injected into the polystyrene foam flows out to the outside through holes, formed by the syringe needles, with the passage of time, leading to a reduction in the flame-retardant effects, and the surface of polystyrene foam has many syringe needle holes formed therethrough, leading to a reduction in the strength of polystyrene foam.

<6>

[Disclosure] [Technical Problem]

<7> The present invention has been made in order to solve the above- described problems occurring in the prior art, and it is an object of the present invention to provide a composition for producing expanded polystyrene foam, in which a self-extinguishing flame-retardant material is introduced into beads for producing molded polystyrene foam, such that the beads have self-extinguishing properties without deteriorating the excellent properties of polystyrene foam, such that they do not spread flame or do not generate noxious gases, and a method for producing expanded polystyrene foam of flame retardancy grade 3 using the composition.

<8>

[Technical Solution]

<9> To achieve the above object, the present invention provides a flame- retardant bead composition for producing expanded polystyrene foam, which has a self-extinguishing flame-retardant material introduced therein and is produced by pre-expanding a mixture of expandable polystyrene particles with the flame-retardant material, as well as flame-retardant expanded polystyrene foam molded from the bead composition.

[Advantageous Effects]

<io> According to the present invention, a flame-retardant material in place of air is introduced into cells formed in beads forming expanded polystyrene foam, such that, when the polystyrene foam catches fire, the polystyrene foam is melted while flame-retardant gas is generated from the inside of the polystyrene foam to block oxygen, whereby the polystyrene foam shows flame retardant properties. In addition, it is possible to obtain flame-retardant polystyrene foam, which can be recycled without deteriorating thermal insulation, shock-absorbing and processability properties, which are the characteristic properties of polystyrene foam.

[Description of Drawings]

<i2> FIG. 1 is a process diagram showing a method for producing flame- retardant beads for producing expanded polystyrene foam.

<i3> FIG. 2 shows an example of producing flame-retardant beads according to the method of the present invention.

<i4> FIG. 3 is a test report on flame-retardant polystyrene foam of the present invention!

<i5> *Description of important reference numerals used in the figures* <i6> Sl: first mixing step; S2: second mixing step; <i7> S3: third mixing step; S4: pre-expanding step; <i8> Pl: first mixture; P2: second mixture; and <i9> P3: third mixture.

<20>

[Best Mode]

<2i> FIG. 1 is a process diagram showing a method for producing a flame- retardant bead composition according to the present invention.

<22> As shown in FIG. 1, the method according to the present invention comprises-' a first mixing step (Sl) of mixing silicic acid, a surfactant and neozapon powder in the same weight ratio to obtain a first mixture (Pl); a second mixing step (S2) of mixing expandable polystyrene (EPS), as a raw material for producing expanded polystyrene foam, with, based on the weight of the expandable polystyrene, about 2.4 wt% of the first mixture (Pl) and about 0.8 wt% of liquid glass to obtain a second mixture (P2); a third mixing step (S3) of mixing the second mixture (P2) with, based on the weight of the second mixture, 0.8 wt% of ammonium phosphate and 0.8 wt% of a surfactant to obtain a third mixture (P3); and a pre-expanding step (S4) of pre-expanding the third mixture (P3) at about 90-120 °C to obtain beads having the flame- retardant material introduced therein.

<23> Specifically, in the present invention, the third mixture is the flame- retardant bead composition of the present invention. When the third mixture is pre-expanded, the flame-retardant beads having the flame-retardant material introduced therein can be obtained. When the flame-retardant beads are subjected to a compression molding process, expanded polystyrene foam is obtained.

<24> FIG. 2 illustrates an example of producing flame-retardant beads according to the method of the present invention. According to the example shown in FIG. 2, the flame-retardant material is introduced into the beads for producing expanded polystyrene foam.

<25> Specifically, the second mixing step (S2) of adding the first mixture (Pl) and liquid glass to the expandable polystyrene as a raw material is carried out, the second mixture (P2), in which the first mixture ⁽Pl) and liquid glass adhere to the surface of the expandable polystyrene, is obtained. When the third mixing step (S3) of mixing the second mixture with ammonium phosphate and the surfactant is carried out, the third mixture (P3), in which ammonium phosphate and the surfactant are uniformly coated on the first and second mixtures (Pl) and (P2) adhered to the surface of the expandable polystyrene beads, is obtained. When the third mixture is expanded in the pre-expanding step, the expandable polystyrene beads are expanded, while the first, second and third mixtures (Pl), (P2) and (P3) coated on the surface of the expandable polystyrene are introduced into the resulting beads together with expanding gas due to the expansion of the expandable polystyrene. The expanding gas is discharged with the passage of time, and thus in the beads, only the flame-retardant material and a small amount of the expanding gas are present. In this way, the beads as raw materials for producing expanded polystyrene foam can be obtained.

<26> Meanwhile, FIG. 3 is a test report on flame-retardant expanded polystyrene foam obtained by compression molding of the beads according to the present invention. As can be seen in FIG. 3, the flame-retardant expanded polystyrene foam was tested according to testing method for incombustibility of internal finish material and element of buildings (KS F 2271-1998) and, as a result, it had no after-flame, and the time for mice to stop action was longer than 14 seconds.

Claims

[CLAIMS] [Claim 1]

A flame-retardant bead composition for producing flame-retardant expanded polystyrene foam, which is produced using a method comprising: a first mixing step (Sl) of mixing silicic acid, a surfactant and neozapon powder to obtain a first mixture (Pl); a second mixing step (S2) of mixing expandable polystyrene (EPS), as a raw material for producing expanded polystyrene foam, with the first mixture (Pl) and liquid glass to obtain a second mixture (P2); and a third mixing step (S3) of mixing the second mixture (P2) with ammonium phosphate and a surfactant to obtain a third mixture (P3).

[Claim 2]

The flame-retardant bead composition of Claim 1, wherein the first mixture (Pl) is obtained by mixing the silicic acid, the surfactant and the neozapon powder in the same weight ratio.

[Claim 3]

The flame-retardant bead composition of Claim 1, wherein the second mixture (P2) is obtained by mixing the expandable polystyrene with, based on the weight of the expandable polystyrene, 2.4 wt% of the first mixture (Pl) and 0.8 wt% of liquid glass.

[Claim 4]

The flame-retardant bead composition of Claim 1, wherein the third mixture is obtained by mixing the second mixture (P2) with, based on the weight of the second mixture, 0.8 wt% of ammonium phosphate and 0.8 wt% of the surfactant.

[Claim 5]

A method for producing flame-retardant beads for producing flame- retardant polystyrene foam, the method comprising: mixing silicic acid, a surfactant and neozapon powder in the same weight ratio to obtain a first mixture (Pl)I; mixing polystyrene foam with, based on the weight of the polystyrene foam, 2.4 wt% of the first mixture and 0.8 wt% of liquid glass to obtain a second mixture (P2); mixing the second mixture with, based on the weight of the second mixture, 0.8 wt% of ammonium phosphate and 0.8 wt% of a surfactant to obtain a third mixture (P3); pre-expanding the third mixture by heating it at about 90-120 "C to obtain beads having the flame-retardant material introduced therein.