KR20150074418A - Fire retarded foam particle of polystyrene and foam block of polystyrene using it - Google Patents

Abstract

The present invention relates to a flame retardant polystyrene foam particle, and a flame retardant foam using the same. The flame retardant polystyrene foam particle is manufactured by the steps of: primarily (preliminarily) foaming foamable polystyrene beads; filling pre-foamed ball-shaped foam particles in a cylindrical flame retardant process chamber, pressing the filled foam particles with a circular plate having a plurality of holes punched therethrough to immerse the foam particles therein in a state of being compressed to have 1/2-1/3 volume thereof, to inject a flame retardant liquid, rising the circular plate to release the pressure, and repeating the pressing and releasing operations to inject the flame retardant liquid into an internal structure of the foaming particles; removing the circular plate from the cylindrical flame retardant process chamber, and adding fine powders of a flame retardant mixture to the cylindrical flame retardant process chamber to stir the same, thereby directly attaching the fine powders to fine gap and a main part of a foam particle surface to improve flame retardancy of a surface layer thereof; removing the flame retardant liquid, and extracting the foam particles; and removing a part of the flame retardant liquid injected into the foam particles, and drying the foam particles. In addition, the foam is prepared by secondarily foam-fusion forming the foam particles.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a flame-retardant foamed particle and a foamed block of a polystyrene-based foam,

The present invention relates to a flame retardant primary foamed particle of a flame retardant polystyrene and a flame-retardant foam using the same. More specifically, the present invention relates to a flame-retarded foamed flame retarded foamed bead, Of the expanded particles were pressed with a circular pressing plate having a diameter of 2 to 3 mm smaller than the inner diameter of the treatment chamber to reduce the volume of the expanded particle accumulating body to 1/2 to 1/3, , A surfactant and a dispersing agent are added to the flame retardant solution to fill the foamed particles so that the foam particles can be immersed in the flame retardant solution. The operation of releasing the pressure by lifting the circular pressure plate and pressing it again is repeated several times, Then the original plate was lifted and moved, and the flame-retardant mixed powder was continuously added to the flame-retarding liquid and stirred Next, the present invention relates to a flame retarded foam obtained by discharging a flame retardant and removing softened expanded particles, lightly dewatering and drying the resulting flame retarded expanded polystyrene expanded particle and a foamed flame-retarded foam.

The aqueous ammonia solution is an aqueous solution in which 1 to 5% by weight of the aqueous ammonia solution is dissolved in water. A small amount of anionic surfactant and dispersant is added to the aqueous ammonia solution together with the flame retardant. Ammonium phosphate and borax are used as flame retardants, and the expansion ratio may vary depending on the use of the foam. For example, as a complicated structure, particularly, a foam material for packaging a large load content as a packaging material is a foam such as a low-foam foam material such as a heat insulating material, a sound absorbing material, and a sandwich type board, and foams having an expansion ratio of 10 to 100.

In the present invention, the expansion ratio of 40 to 50 times is adopted in consideration of permeability of the flame retardant. As in the present invention, all of the beads for fusion-molding contain aliphatic hydrocarbons such as propane, butane and pentane as blowing agents. They are impregnated into polymer particles during polymerization or in an aqueous dispersion system in an autoclave. The polystyrene beads of the ball have a particle diameter of 1 to 2 mm, but some of them are smaller or larger depending on the application, and the polystyrene beads of 1 to 2 mm are used in the present invention.

The primary bead expanded particles formed by primary foaming with the beads are characterized in that they are not completely infiltrated even if they are immersed in water or a flame retardant solution, and that the surface of the expanded particles is hardly wetted even to the surface due to water repellency due to oiliness. Even if the surface is damaged by roughening the bead due to the high penetration of water, the infiltration of water is hardly caused by the internal air pressure of the high-yielding particles, and it is difficult to control the magnification at the time of secondary foaming.

Also, surface wetting can be achieved by adding a surfactant to water or a flame retardant solution to activate the interface, but there is a characteristic that penetration can not be expected.

The present inventors paid attention to the circular returnability due to the elasticity of the primary foamed bead in the process of research and experiment for many years, repeatedly operated to release the pressure in the state where the foamed bead was compressed to reduce microcracks, The inventors of the present invention have arrived at the present invention by recognizing that the elasticity of the spherical expanded particles causes a depressurization phenomenon in the bead foam in the circular return phenomenon.

Foamed polyetylene fusion molding is a breakthrough method developed by BASF of Germany and has been patented in major countries in the world. It is a high-tech, high-foaming product and has no brittleness like other materials It has a high yang ratio and a strong film on the surface. It is excellent in insulation. It can uniformly obtain thickness, dimension and density. It also has excellent cold resistance and low mechanical strength even at -60 ℃. And can be said to be a foam having a feature that mechanical processing is very easy.

Because of the above characteristics, the applications can be varied.

The primary prefoamed particles are used for buffering purposes as they are, but in recent years, buoyancy is used by foaming in the ship when lifting a ship. Particularly, the most used ones are formed from one sheet at the beginning, Sliced boards are widely used as insulation materials for ceilings, general merchandises, low-temperature warehouses, automobiles, ships, etc. for general purposes.

In addition, among the uses of fusion molded products, packaging materials have characteristics such as lightness, beauty, buffering property, dimensional uniformity, and are used in various fields such as precision instruments, pharmacopoeias ranging from radio to refrigerator, cosmetics, pharmaceuticals, glassware and foodstuffs.

Especially, in recent years, packaging of the refrigerator and the motor cycle has been carried out to reduce packaging labor costs.

It is widely used in various fields such as dolls, airplanes, boats, red eyes that do not scratch, decorative characters, and display structures, which are used for containers such as ice cases, thermos bottles and the like for lifeguards, fishing rods,

However, it is used for insulation, insulation, dustproofing, soundproofing, etc., which is widely used in the construction of a board. However, since it has no flame retardancy (flame retardancy), it can not be used as a heat insulating material for a heat pipe or a heat shielding material for a high temperature.

Because of its excellent physical properties, which are characteristic of polystyrene foam, it is most widely used as a foam and particularly advantageous in foaming at a high magnification. It is very light and cheap and is competitive as a foam and is the most widely used foam. However, do. For example, there is a limitation in that it can not be used as a material for keeping a heat pipe at 150 ° C or higher or for preventing heat radiation at a high temperature.

In order to solve these problems, a lot of research and efforts have been made to impart flame retardancy (flame retardancy) to the styrene foam product. However, as heat resistant foam, there are no satisfactory foam products yet, In addition, there have been attempts by those engaged in this field to form beads of foamed beads whose foamed beads are coated with an adhesive material and foamed first, The foamed body can be said to be a foamed molding body by adhesion of an adhesive containing a flame retardant agent by coating between the primary foamed particles rather than the foamed body, and the surface of the foamed body is hardened by the hardening of the adhesive, so that the original smooth and elastic surface can be expected There are some problems with the products.

A more specific example of a conventional flame retardant polystyrene foam is disclosed in Korean Patent Registration No. 10-10180938 as a technique of the related art in "Production of self-extinguishing flame retardant beads and flame retardant foamed styrofoam manufacturing system using the flame retardant beads" Are described. In order to prevent the aggregation of beads by an adhesive material and a flame retardant coated with a mixture of flame retardant and water glass on the bead surface by mixing a mixture of two or more flame retardant materials selected from domestic, neophyton and sodium chloride, foamed polystyrene beads and water glass And a lubricant (surfactant and ammonium phosphate) are also stirred together to form a lubricating film on the surface of the bead particles. The beads are pre-expanded by heating at 90 to 120 ° C to obtain a foamed product (fusion foam) can do.

In the above-described flame retarding method, the expandable polystyrene bead is a polystyrene resin whose surface is dense and has a linearity ranging from 1 to 2 mm in which the liquid does not penetrate.

When such a flame retardant mixture and an adhesive water-glass mixture are coated on the beads, the mixture is not penetrated into the beads at all and a film of a mixture of a certain thickness is formed on the surface layer of the beads. The state of the expanded particles of the spherical body preliminarily foamed with the film formed thereon is partially attached to the surface of the foamed spherical body expanded particles after the film of the mixture formed on the bead is ruptured. For example, when the foam is foamed at a magnification of 27 times as a normal primary (preliminary) expansion ratio, the coating film formed on the beads ruptures by foaming, and a coating film corresponding to 1/9 of the foamed particle surface is partially adhered to the surface of the expanded particles, Can be said to be a foaming face of polystyrene. Therefore, it can be said that the flame retardant function can hardly be expected. Further, when the water glass mixture is coated on the surface of the foamable bead, when the water glass is cured, it is formed as a hard and strong film, There is a problem that it is difficult to adjust a predetermined magnification extremely.

As another prior art, Korean Patent Registration No. 10-0991189 discloses a technical content of "a flame retardant coating agent, a method for producing the same, and a method for treating a foamed styrofoam particle flame retardant ". Herein, a description of the technical content of the method for treating flame-retardant foamed styrofoam particles is as follows. That is, a method of flame-retarding foamed particles (foamed styrofoam particles) of a spherical body preliminarily foamed with expandable polystyrene beads to 100 parts by weight of watery glass 0.3 to 0.5 parts by weight of a heat resistant corn oil, 2 to 3 parts by weight of a film-peeling preventing component, 4 to 6 parts by weight of a flame retardant component, 0.4 to 0.5 parts by weight of calcium hydroxide and 0.35 to 0.45 part by weight of an emulsifier is applied to form a film The main component of the coating agent may be water glass such as sodium or potash silicate, and if it is dried, a glass film is formed on the surface of the expanded particles, so that the surface of the expanded particles may have flame retardancy. However, In order to obtain a foam, a foaming fusion molding process must be carried out. It is difficult to expect a foam by fusion molding because of the glass coating in the melting temperature range of 100 to 130 ° C. In the original fusion molding, the particles and particles of the prefoamed styrofoam are fusion-molded at a temperature in the range of the melting point of polystyrene. Since a glass film is formed on the surface of the polystyrene, fusion between the expanded particles and the particles is difficult.

As described above, the water glass containing the flame retardant is coated on the surface of the foamed polystyrene beads or beads of the preliminarily prefoamed primary particles to form a film, and the flame retardancy of the internal structure of the beads or the internal structure of the expanded particles The entire material can not be flame retarded and merely a glass film is formed only on the surface, so that secondary fusion molding is difficult and the whole flame retardation can not be expected.

The present invention solves the problems of the prior art polystyrene foam smearing method. The foamed polystyrene beads are first compressed by expanding the foamed beads and then decompressed. The foamed particles are then restored to their original state, A decompression phenomenon is generated in the particles to uniformly penetrate the flame retarded solution dissolved or dispersed in the aqueous ammonia solution in the microporous structure of the expanded particles, and at the same time, a void or unevenness The flame retardancy of the surface of the expanded particles is strengthened by attaching the flame retardant particles to the surface of the flame retardant, and the flame retardancy is imparted to the whole expanded particles and the secondary foamed fusion molding can be easily achieved. It is an object to obtain a molded flame-retardant foam.

The spherical foam particles, which have been preliminarily foamed with expandable polystyrene beads, are filled in a cylindrical egg-softening treatment chamber of the egg-softening apparatus with a certain amount of expanded particles and pressed with a circular pressing plate having a diameter of 2 to 3 mm smaller than the inner diameter of the cylindrical egg- The flame retardant added with flame retardant, anionic surfactant and dispersant to the aqueous ammonia solution was injected into the aqueous ammonia solution while reducing the bulk volume to 1/3 ~ 1/2, and then the pressure plate was lifted to release the pressure and pressurize again The press plate is lifted, and then the flame retardant powder, the natural fiber powder and the mixed powder of the mineral fine powder are continuously added to the flame retardant liquid in a predetermined amount, and then the flame retardant liquid is discharged and the spherical foam particles are taken out, After defoaming, the dried and defatted softened foamed particles are subjected to secondary foamed fusion molding This could achieve the objectives of the present document, so get the foam.

The flame retardant is uniformly penetrated into the inner structure of the expanded particles and the flame retardancy is strengthened to the surface layer, and the flame retardancy of the surface layer is excellent, and the conventional polystyrene beads are uniformly dispersed on the surface of the expanded particles Unlike the flame-retardant foam particles which are simply coated with a mixture of water glass and a flame-retardant substance, the flame-retarded polystyrene foam particles having excellent secondary foam melt-bonding formability and the foam obtained by the secondary foam fusion molding using the same, It is possible to secure the original function of the polystyrene foam such as insulation, insulation, soundproofing and dustproof as well as keeping the original shape, and it can be said to be a flame retardant foam which can be widely used as a high-temperature tube and a high-temperature barrier material with excellent flame retardancy.

1 is a cross-sectional view of a foamed particle cracking device (A)
2 is a perspective view of the circular platen;

The present invention relates to a foamed polystyrene bead in which foamed polystyrene beads are softened to the inside as well as to the surface of spherical foam particles which are preliminarily foamed, The present invention relates to a flame retarded foam obtained by secondary fusing and fusion molding of flame retarded foamed particles and foamed particles so as to smoothly achieve cold fusion molding. More specifically, foamed foamed beads having a diameter of 1 to 2 mm are stretched by 30 to 50 times A step of foaming at an expansion ratio of

The foamed spherical particles in the primary foamed state are collected in a cylindrical egg-softening chamber of the foamed particle destruction preventing device, and the foamed particles are pressed with a circular pressing plate to reduce the accumulated foamed particles from 1/2 to 1/3 A two-step process in which the flame-retardant liquid is injected into the inside of the expanded particle by repeating the operation of injecting the flame-retardant liquid so that the expanded particles can be locked in the state, releasing the pressure by raising the pressure plate, releasing the pressure again,

A three-step process in which a fine powder of a flame-retardant mixture is stirred while being stirred by a stirrer while a round pressing plate of a softening device is removed,

A four-step process of discharging the flame-retardant liquid and taking out the expandable particles impregnated with the flame-retardant liquid

The flame retarded foam obtained by the secondary blow-fusion molding can be regarded as the flame-retarded foam obtained by performing the five-step process of partially removing the flame-retarded liquid impregnated into the taken-out expanded particles and drying it.

In the first step of the above method, spherical expanded particles having a diameter of 3.2 to 3.7 mm can be obtained by foaming a bead having a diameter of 1 mm to 30 to 50, and when the bead having a diameter of 2 mm is foamed at a rate of 30 to 50, It is difficult to penetrate the flame retardant liquid. When the expansion ratio is too large, the tensile strength and the pressure resistance become poor and the surface becomes rough. In the fusion molding, the foamed particles . If the pressure and the pressure-sensitive agent are repeated with the circular pressing plate within the above-mentioned magnification range, depressurization phenomenon occurs in the inside of the compressed foamed particles, and the penetration of the flame retardant into the foamed particle becomes easy.

As shown in Fig. 1, the apparatus for flame-retardant flame retardant (A) used in the second step of the present invention is a cylindrical container divided into horizontal partition plates 1, the upper part is an egg softening treatment chamber 2, And a circular pressure plate 6 suspended by fixing the piston 5 of the hydraulic cylinder 4 to its center portion is suspended in the softening treatment chamber 2 and is fixed to one side of the lower side of the hardening treatment chamber 2 (9) provided with a flammable liquid discharge pipe (8) having a valve (7) and connected to an upper portion of the flame retarding liquid storage chamber (2) and discharging flame- A discharge port 10 is formed in the bottom of the flame retardant liquid storage chamber 3 and a flame retardant liquid discharge pipe 12 provided with a motor 11 is provided at the lower side of the flame retardant liquid storage chamber 3, Softening device.

Here, the circular platen 6 has a diameter which is 2 to 3 mm shorter than the inner diameter of the cylindrical burnishing treatment chamber and innumerable holes 13 having a diameter of 2 mm are drilled in the circular disk. At the center thereof, 5) are fixed (see Fig. 2). This circular pressing plate 6 presses an aggregate of the expanded particles on the expanded particles 14 accumulated in the incombustible treatment chamber 2. When the expanded particle accumulating body is pressed by the circular pressing plate 6, The flame-retardant liquid 15 passes through the gap formed between the edge of the circular plate and the inner wall of the flame-retardant chamber, and when the circular pressure plate is lifted to release the pressure, the flame retardant liquid passes through the hole and the gap So that it goes down.

Repeated pressurization and depressurization with such a circular pressure plate causes the flame-retardant liquid to penetrate into the interior and re-emerge. As a result, a passage is formed in the pore structure in the expanded particles, the surface is roughened, The process of returning to the original shape is repeated, and when the elastomeric foam particles are reduced and returned to the circular shape (spherical shape), the decompression phenomenon occurs in the expanded particles, and the external flame retardant liquid is instantly penetrated.

When the foaming ratio of the expandable polystyrene beads is low, a strong film is formed on the surface and the structure becomes dense, so that the infiltration of the flame retardant solution is reduced, and when the foam is foamed, the foaming particles become tacky and the surface becomes rough. The foaming magnification becomes difficult to adjust, and the tensile strength and pressure resistance of the foam become poor.

Further, the flame retardant solution is prepared by adding 2 to 12 parts by weight of ammonium phosphate monobasic, 1 to 5 parts by weight of anhydrous borax, 0.2 to 0.5 parts by weight of an anionic surfactant and 0.1 to 0.3 parts by weight of a dispersant to 100 parts by weight of an aqueous ammonia solution of 1 to 5% And homogenized.

When such a flame retardant has a high viscosity, a film can be formed on the surface of the spherical expanded particles which are firstly foamed, so that fusion between the expanded particles becomes difficult in the secondary fusion molding, and the strength of the foam is lowered. When using less flame retardant, Can not be expected.

Ammonium monophosphate is a colorless odorless substance which is stable in air and easily soluble in water. It is easily combined with cellulose of natural fiber and has dehydration function when it is oxidized. The molecule of phosphorus compound is a polymer in chain And when a high temperature is generated, the polymer of the phosphorus compound is decomposed and oxidized into a phosphorus compound which performs a dehydration function. Phosphorus compounds have flame retardancy (flame retardancy) and have cooling and vasopressor functions, and the acid phosphorus itself has the function of blocking oxygen by forming an oxide film on the bead surface

The anhydrous borax which constitutes the flame retardant liquid is white crystal and has a mp of 741 ° C and a specific gravity of 2,367. It is slightly soluble in water and is a non-flammable flame retardant. It has waterproof and sterilizing insecticidal function and does not cause fungi or insects. It is a functional material having excellent flame retardancy which is turned off.

The anionic surfactant activates the surface of the spherical expanded particles with oil seeping to make them hydrophilic and emulsifies the fine powder of the flame retardant mixture which is emulsified in the step 3 with the flame retardant, The homogeneity of the flame-retardant liquid can be ensured. The fine powder of the colorless or white flame retardant mixture is fine powder of ammonium phosphate, boron or borax, natural fiber and dolomite, and is a colorless or white material for improving the whiteness of the foam. The blending ratio of the mixture is ammonium phosphate powder, boron, borax powder , Natural fiber powder, and dolomite powder in the order of 1.5: 1: 0.5: 1.

The powder of such a mixture is added while stirring the flame retardant liquid and the expanded particles, so that the flame retardant mixture fine particles are accumulated on the recesses generated by micro-gap or foaming generated by repeated pressing of the circular pressure plate and the pressure- And the fused surface remains on the surface of the expanded particles because it is not adhered to the partially smooth surface or the convex portion due to the stirring speed. This phenomenon enables secondary foaming and fusion molding.

The amount of the flame-retardant mixture fine powder added is 4 parts by weight based on 100 parts by weight of ammonia water. It is dewatered to 30 to 40% of the flame retarded liquid contained in the flame-retarded expanded particles taken out so that the flame-retarding liquid does not flow out, followed by natural drying and aging for 12 to 24 hours to stabilize the expanded particles. If it is necessary to reduce the water content in some cases, it is kept at a temperature of 40 to 50 ° C and dried under reduced pressure to obtain a flame retarded foam having a content of 1% or less, and the foam is obtained by secondary foam fusion molding. Here, if the drying temperature exceeds 50 ° C, it will approach 70 ° C, which is the softening point of polystyrene. Therefore, it should never exceed 50 ° C.

In the drying process and the secondary molding process, most of the ammonia is evaporated and a little odor is left in the foam, but odorless foam can be obtained after 1 to 2 neutralization.

The flame-retardant liquid taken out from the outside and the flame-retardant liquid generated at the time of dewatering are regenerated again by adjusting the content of the additive.

The foamed particles of the primary foamed spherical body obtained in the above manner are uniformly infiltrated into the inner structure of the three-dimensional network structure, and the flame-retardant particles are uniformly dispersed in fine irregularities and gaps generated by the repeated processes of the foaming process or the pressure- As a result, the entire foamed particles are smoothed and the surface of the foamed particle is partially surface and fine protrusions are formed on the surface, so that the softened foamed particles can be smoothly attained by the secondary fusion molding, An excellent flame retardant foam can be obtained by foaming press molding.

Examples are shown in order to clarify the technical structure of the foam according to the present invention and to examine its effect.

EXAMPLES (1) Production of Foam Samples of the Invention

Foamed polystyrene beads having a diameter of 1 mm were foamed at a magnification of 40 times with a high-pressure steam, and then half of the foamed polystyrene beads were accumulated in a cylindrical tank. The circular pressure plate was lowered thereon, 10 parts by weight of ammonium phosphate monobasic, 3 parts by weight of borax, 0.3 parts by weight of an anionic surfactant and 0.2 parts by weight of a dispersing agent were added to 100 parts by weight of an aqueous ammonia solution to obtain a homogenized flame retardant, And then pressurized to a half volume of the foamed bead integrated volume and released again. After the circular pressure plate was lifted and moved to introduce the rotor blade, the foamed beads were slowly stirred And 4 parts by weight of the flame-retardant mixture fine powder were stirred for 5 minutes. Then, the flame-retardant liquid was discharged, and the softened foamed particles were taken out and dewatered lightly 30% of the flame retarded liquid contained in the expanded particles was dehydrated, naturally dried for 24 hours, and then dried under reduced pressure at a temperature of 40 to 50 ° C to obtain 1% or less of the flame retarded expanded particles. Of the foam sample (A).

Comparative Example (2) Preparation of ordinary foamed samples

Foamed styrene beads having a diameter of 1 mm were foamed at a rate of 40 times with a live steam and foamed particles were obtained by molding the foamed particles by a secondary fusion molding to obtain a foamed sample (B) having a size of 10 x 10 x 10 cm.

Example (3) Experimental Example

(A) and (B) were placed on the bottom of a cylindrical glass container equipped with a thermometer so that the sample would not directly touch the sample, the samples (A) and (B) Were observed.

The sample (A) was in a state in which the volume of the sample (A) was slightly decreased between 400 ° C and 500 ° C with increasing temperature, but there was no circular damage. At 600 ° C, the volume began to decrease and began to carbonize. It was completely carbonized and maintained at 600 ° C, and the carbonized residue remained at 800 ° C.

When the temperature of the sample (B) reached 120 ° C while the temperature was elevated, the edge portion and the side portion of the sample (B) began to become gentle, and while the molten melt remained on the ceramic container And the carbonized powder was placed on the container at around 800 ° C.

In the above experiments, the volume was slightly changed to 500 ° C, but it was presumed to maintain the original shape, and it was found that the softening effect was not ignited even in the range of 700 to 800 ° C.

On the other hand, in Sample B, the function of the foam began to be lost when the temperature was higher than 120 ° C., and the function of the foam completely disappeared at 200 ° C., and there was a risk of fire due to ignition at 700 ° C.

A: Expanded particle fire retarding device 8: Flame retardant liquid discharge pipe
1: Horizontal partition plate 9: Lock cap
2: cylindrical burning treatment chamber 10: foamed particle outlet
3: Flame Retardant Liquid Storage Room 11: Motor
4: Hydraulic cylinder 12: Flame retardant delivery pipe
5: piston (circular platen shaft) 13: hole
6: Circular pressure plate 14: Expanded particles
7: valve 15: flame retardant liquid

Claims (7)

A step 1 of foaming foamed styrene beads having a diameter of 1 to 2 mm at a foaming magnification of 30 to 50 times;
The spherical foam particles of the primary prefoamed spheres are packed in a cylindrical egg-softening chamber of a foamed particle incineration apparatus and filled with a certain amount of expanded particles, and then pressed with a circular pressing plate, 3, the flame-retardant solution is injected so that the expanded particles can be locked, then the pressure plate is lifted to release the pressure, and then the pressure is repeatedly repeated to infiltrate the flame-retardant solution into the internal structure of the expanded particles.
A three-step process in which fine powder of a flame-retardant mixture is dropped into a cylindrical incombustible treatment chamber while the circular pressure plate is removed from the incombustible treatment chamber and stirred with a stirrer to thereby enhance the flame retardancy of the surface of the expanded particles;
A four-step process of discharging flame-retardant liquid and extracting flame-retarded expanded particles;
A step of dehydrating and drying 30 to 40% of the flame retarded liquid infiltrated into the flame-retarded expanded particles taken out; A flame retardant foam obtained by secondary foaming fusion molding with the flame retarded polystyrene foam particles of claim 1 The method according to claim 1,
The foamed particle cracking device has a cylindrical container divided by a horizontal partition plate 1 and the upper part is composed of a flame retarding liquid storage chamber 3 in the lower part of the flame retardation treatment chamber 2 and the hydraulic cylinder A circular pressure plate 6 suspended vertically to the piston 5 of the flame retardant treatment chamber 2 is suspended and a flame retardant liquid discharge pipe 7 having a valve 6 is provided at one side of the lower side of the egg- And a foamed particle discharge port 10 having a lock cap 9 for discharging flame-resistant foamed particles is formed on the side of the bottom of the flame retardant treatment chamber 2, which is connected to an upper portion of the flame- And a flame-retardant liquid discharge pipe 12 equipped with a motor 11 is provided on the lower side of the flame-retardant liquid storage chamber 3 and connected to the upper end of the softening process chamber 2 Characterized in that the hardened polystyrene expanded particles The method of claim 3,
The diameter of the circular platen 6 is 2 to 3 mm shorter than the inner diameter of the cylindrical incombustible treatment chamber 2 and the circular platen has innumerable holes of 2 mm in diameter and the piston 5 of the hydraulic cylinder 4, Is a circular press plate which is fixed vertically. The soft-pressed polystyrene expanded particles The method according to claim 1,
The flame retardant solution is prepared by mixing 2 to 12 parts by weight of ammonium phosphate monobasic, 1 to 5 parts by weight of boron or anhydrous borax, 0.2 to 0.5 parts by weight of an anionic surfactant and 0.1 to 0.3 parts by weight of a dispersant in 100 parts by weight of 1 to 5% And a homogenized flame retardant. The method according to claim 1,
Wherein the flame retardant mixture fine powder is a white flame retardant mixed powder having a mixing weight ratio of 1.5: 1: 0.5: 1 as fine powder of ammonium phosphate, boron or borax, natural fiber and dolomite. The method according to claim 1,
The amount of the flame-retardant mixture added is 4 parts by weight based on 100 parts by weight of the aqueous ammonia solution.

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