KR20130055403A - Non flammable expandable polystyrene polymerized beads and method for preparing the same - Google Patents

Abstract

The non-combustible expanded polystyrene-based polymerized beads of the present invention are subjected to primary polymerization of (a11) styrene-based monomers, (a12) char-forming thermoplastic resins, (a21) inorganic foam particles, and (a22) carbon fillers to form a core (A). To prepare; In addition, a monomer having a glass transition temperature of 120 ° C. or lower is added to the core (A) to prepare a second polymerization to form a skin layer (B). Foams prepared from the non-combustible expanded polystyrene-based polymerized beads exhibit nonflammability, heat insulation performance, and excellent mechanical strength of KS F ISO 5660-1, flame retardant material (grade 3 flame retardant), not self-extinguishing flame retardant.

Description

Non-flammable expanded polystyrene-based polymerized beads and method for manufacturing the same {NON FLAMMABLE EXPANDABLE POLYSTYRENE POLYMERIZED BEADS AND METHOD FOR PREPARING THE SAME}

The present invention relates to non-combustible expanded polystyrene-based polymerized beads and a method for producing the same. More specifically, the present invention polymerizes a char-generating thermoplastic resin, an inorganic foam particle, and a carbon filler together with a styrene monomer to form a skin layer by polymerizing a monomer having a glass transition temperature of 120 ° C. or less, thereby forming a skin layer. The present invention relates to a non-flammable expanded polystyrene-based polymerized bead exhibiting excellent thermal insulation performance and excellent mechanical strength and a method of manufacturing the same.

Generally, foamed molded articles of expandable polystyrene have high strength, light weight, cushioning property, waterproof property, heat insulation property and heat insulation property and are used as packaging materials for household appliances, agricultural products boxes, Among them, more than 70% of the domestic demand for foamed polystyrene is used as a core material for house insulation and sandwich panels.

However, in recent years, foamed polystyrene has been pointed out as a fire causing factor and its use is limited. Therefore, in order to apply expandable polystyrene to a house insulation material, it is required to have a nonflammability at the level of a flame retardant material.

Korean Patent No. 0602205 discloses a method for producing flame-retarded polystyrene expanded particles by coating and curing expanded graphite, a thermosetting resin and a curing catalyst on polystyrene foam particles.

Korean Patent No. 0602196 discloses a polystyrene expanded particle comprising a metal hydroxide compound selected from the group consisting of aluminum hydroxide (Al (OH) ₃), magnesium hydroxide (Mg (OH) ₂), and mixtures thereof, a thermosetting liquid phenolic resin, Discloses a method for producing flame retarded polystyrene foam resin particles comprising coating and crosslinking a resin curing catalyst.

The above-mentioned patents cross-link the surface of the foamed beads with a thermosetting resin, thereby deteriorating the secondary foaming by steam, and causing fusion of the particles and degradation of strength during the process of forming the molded article (panel). In addition, the above-mentioned patents have disadvantages such as environmental pollution due to the use of thermosetting resins such as phenol and melamine, facility investment for coating thermosetting resins or inorganic materials, and deterioration of physical properties of resins due to inorganic substances.

Therefore, there is a continuing need for a polystyrene foam resin capable of preventing fusion and strength deterioration in the process of forming a molded article while preventing environmental pollution.

It is an object of the present invention to provide expanded polystyrene-based polymerized beads having excellent non-combustibility beyond flame retardant materials in KS F ISO 5660-1 and not a self-extinguishing flame retardant, and a method of manufacturing the same.

Another object of the present invention is to provide a non-combustible expanded polystyrene-based polymerized bead exhibiting excellent incombustibility, thermal insulation performance and excellent mechanical strength and a method of manufacturing the same.

It is still another object of the present invention to provide a non-flammable expanded polystyrene polymerized beads and a method for producing the same, which can be manufactured with little equipment investment without causing environmental pollution.

Another object of the present invention is to provide a non-flammable expanded polystyrene-based polymerized bead having excellent processability and a method for producing the same.

Still another object of the present invention is to provide a non-flammable expanded polystyrene-based polymerized beads and a method for manufacturing the same, which are easily sized by introducing a polymerization method.

It is another object of the present invention to provide a method for obtaining a non-combustible expanded polystyrene-based polymerized beads of a desired size with high yield.

Still another object of the present invention is to provide a non-flammable expanded polystyrene-based polymerized bead which can increase the content of carbon particles and does not require a separate screening step, and a method of manufacturing the same.

Still another object of the present invention is to provide a flame retardant polystyrene foam using the non-flammable expanded polystyrene polymerized beads.

Still another object of the present invention is to provide a non-flammable polystyrene foam having excellent balance of non-flammability, thermal conductivity and mechanical strength by using the non-flammable expanded polystyrene-based polymerized beads, which is suitable for building materials such as sandwich panels.

These and other objects of the present invention can be achieved by the present invention which is described in detail.

One aspect of the present invention relates to a method for producing a nonflammable expanded polystyrene-based polymerized bead. In an embodiment, the method comprises: (a11) styrene monomer, (a12) char-forming thermoplastic resin, (a21) inorganic foam particles, and (a22) carbon filler to polymerize core (A); And a second polymerization is performed by introducing a monomer having a glass transition temperature of 120 ° C. or lower into the core (A) to form a skin layer (B).

The core (A) is (a11) 65 to 95% by weight of the styrene monomer, (a12) 1 to 10% by weight of char-forming thermoplastic resin, (a21) 3 to 29% by weight of inorganic foam particles and (a22) carbon 0.01 to 30% by weight of the filler is polymerized.

5 to 25 parts by weight of a monomer having a glass transition temperature of 120 ° C. or less is added to 100 parts by weight of the core (A).

The char-generating thermoplastic resin may have an oxygen bond, an aromatic group, or a combination thereof in the main chain.

In one embodiment, the char-generating thermoplastic resin may be selected from the group consisting of polycarbonate, polyphenylene ether, polyurethane, polyphenylene sulfide, polyester, polyimide.

Preferably, the char-generating thermoplastic resin may be selected from the group consisting of polycarbonate, polyphenylene ether, and polyurethane resin.

The inorganic foam particles may be selected from one or more of the group consisting of expanded graphite, silicate, pearlite and white sand.

The inorganic foam particles may have an average particle diameter of 10 to 1,000 μm, and an expansion temperature of 150 ° C. or more.

The carbon filler may be selected from the group consisting of graphite, carbon black, carbon fiber, and carbon nanotube. The carbon filler may have an average particle diameter of 0.1 to 100 mu m.

The monomer having a glass transition temperature of 120 ° C. or less may be selected from the group consisting of styrene and alphamethyl styrene.

In one embodiment, the monomer (A) and the blowing agent having a glass transition temperature of 120 ° C. or lower may be added to the core (A), and then secondary polymerization may be performed.

In another embodiment, the blowing agent may be added to the polymerization during the secondary polymerization.

In another embodiment, the blowing agent may be added after the secondary polymerization.

In an embodiment, at least one additive selected from the group consisting of antiblocking agents, nucleating agents, antioxidants, carbon particles, fillers, antistatic agents, plasticizers, pigments, dyes, heat stabilizers, UV absorbers and flame retardants during the primary or secondary polymerization It can be polymerized by adding.

Another aspect of the invention relates to non-combustible expanded polystyrene-based polymerized beads. In a specific embodiment, it is formed by the above method, and has a structure of the core layer A and the skin layer B formed on the said core surface.

In one embodiment, a core (A) formed by polymerization of (a11) a styrene monomer, (a12) a char-generating thermoplastic resin, (a21) inorganic foam particles, and (a22) a carbon filler; And a skin layer (B) formed on the surface of the core (A) and polymerized with a monomer having a glass transition temperature of 120 ° C. or less, wherein the core (A) and the skin layer (B) are impregnated with a foaming agent. Have

The core (A) is (a11) 65 to 95% by weight of the styrene monomer, (a12) 1 to 10% by weight of char-forming thermoplastic resin, (a21) 3 to 29% by weight of inorganic foam particles and (a22) carbon 0.01 to 30% by weight of the filler may be polymerized.

The ratio of the radius of the core A and the thickness of the skin layer B may be 1: 0.0001 to 1: 0.2.

The non-combustible expanded polystyrene-based polymerized beads may have an average particle diameter of 0.5 to 5 mm.

The weight ratio of the core (A) and the skin layer (B) may be 1: 0.035-0.23.

Another aspect of the invention relates to non-combustible polystyrene-based foams.

The foam is formed by foaming the beads, the heat release rate (THR) is less than 0.9 kW / ㎡ after a 50 mm thick sample heated for 5 minutes at 50 kW / ㎡ radiant heat of the cone heater according to KS F ISO 5660-1, Compressive strength of 19 N / cm ^{2 according} to KS M 3808 Above, bending strength is 37.6 N / cm ² Or more, and the fusion rate may be 20 to 60%.

The present invention has excellent non-flammability in KS F ISO 5660-1 that is excellent in thermal insulation and not self-extinguishing flame retardant, has excellent productivity because it does not need to undergo a separate processing step, and has excellent non-flammability, heat insulation performance and excellent mechanical strength. Non-flammable expanded polystyrene-based polymerized beads and their manufacture which can be manufactured with only a small investment of equipment without causing environmental pollution, have excellent processability, can be easily adjusted in size by introducing a polymerization method, and can increase the content of carbon particles. The present invention provides an incombustible polystyrene foam having excellent non-combustibility, thermal conductivity, and mechanical strength balance using the incombustible expanded polystyrene-based polymerized beads, thereby providing a non-combustible polystyrene foam suitable for building materials such as sandwich panels.

1 is a schematic cross-sectional view of a non-flammable expanded polystyrene-based polymerized bead according to one embodiment of the present invention.

The method for producing a non-flammable expanded polystyrene-based polymerized bead of the present invention comprises (a11) a styrene-based monomer, (a12) a char-generating thermoplastic resin, (a21) inorganic foam particles, and (a22) a carbon filler to polymerize the core. (A) is prepared; And a second polymerization is performed by introducing a monomer having a glass transition temperature of 120 ° C. or lower into the core (A) to form a skin layer (B).

Primary polymerization

In the first polymerization step, a core (A) is formed by polymerizing (a11) a styrene monomer, (a12) a char-generating thermoplastic resin, (a21) inorganic foam particles, and (a22) a carbon filler.

In an embodiment, the styrene monomer may include styrene, alpha-methyl styrene, paramethyl styrene, and the like, but is not limited thereto. These may be applied alone or in mixture of two or more. Among these, preferably styrene.

In an embodiment, the styrene monomer may be used by mixing other ethylenically unsaturated monomers with styrene. Alkyl styrene, divinylbenzene, acrylonitrile, diphenyl ether or α-methyl styrene may be used as the ethylenically unsaturated monomer. In the embodiment, 80 to 100% by weight of styrene and ethylenically unsaturated monomer may be used in a mixture of 0 to 20% by weight.

The styrene-based monomer is 65 to 95% by weight of 100% by weight of (a11) + (a12) + (a21) + (a22).

The char-generating thermoplastic resin (a12) may have an oxygen bond or an aromatic group in its main chain, or may have both an oxygen bond and an aromatic group.

In an embodiment, as the char-generating thermoplastic resin (a12), polycarbonate, polyphenylene ether, polyurethane, or the like may be used, and these may be used alone or in combination of two or more thereof. In other embodiments, polyesters such as PPS, PET, and PcT, polyimides, and the like may also be used. These resins may be used alone or in combination of two or more.

Specific examples of the polycarbonate include those having a weight average molecular weight of 10,000 to 30,000 g / mol, and preferably 15,000 to 25,000 g / mol.

Examples of the polyphenylene ether include poly (2,6-dimethyl-1,4-phenylene) ether, poly (2,6-diethyl- Ether), poly (2-methyl-6-propyl-1, 4-phenylene) ether (2,6-dimethyl-1,4-phenylene) ether, poly (2, 6-dimethyl- (2,6-dimethyl-1,4-phenylene) ether and poly (2,3,6-trimethyl-1,4-phenylene) ether, , 5-triethyl-1,4-phenylene) ether, and the like. Preferably a copolymer of poly (2,6-dimethyl-1,4-phenylene) ether and poly (2,3,6-trimethyl-1,4-phenylene) ether and a poly (2,6- 1,4-phenylene) ether is used, with poly (2,6-dimethyl-1,4-phenylene) ether being most preferred.

The intrinsic viscosity of the polyphenylene ether may be in the range of 0.2 to 0.8 as measured in a chloroform solvent at 25 캜 in consideration of thermal stability and workability.

When the polyphenylene ether is mixed with a styrenic resin due to a high glass transition temperature, it can impart higher heat resistance and can be blended with the styrenic resin at all ratios.

The thermoplastic polyurethane may be prepared by reacting a diisocyanate with a diol compound, and may optionally contain a chain transfer agent. As the diisocyanate, aromatic, aliphatic and alicyclic diisocyanate compounds can be used. Examples of the diisocyanate compound include 2,4-toluylene diisocyanate, 2,6-toluylene diisocyanate, phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyl diisocyanate, 5-naphthalene diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, o-, m- or p-xylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate , Dodecane methylene diisocyanate, cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, and the like.

The diol compound may be a polyester diol, a polycaprolactone diol, a polyether diol, a polycarbonate diol, or a mixture thereof. Diols such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, butane 1,2-diol, butane 1,3-diol, butane 1,4- Diethylene glycol adipate, polyethylene glycol, polypropylene glycol, and the like, but are not limited thereto. Specific examples of the solvent include, but are not limited to, ethylene glycol, propylene glycol, It is not.

In the present invention, the char-generating thermoplastic resin (a12) may include 1 to 10% by weight of 100% by weight of (a11) + (a12) + (a21) + (a22). It is excellent in flame retardancy and mechanical properties in the above range. Preferably it may be included in 1 to 5% by weight.

The inorganic foam body (a21) is at least one selected from the group consisting of expanded graphite, silicate, pearlite, white sand.

Inorganic foam particles in the present invention act as char formers. Therefore, it should be kept unbreakable during melt extrusion with the resin, and it is required to have a constant size to satisfy flame retardancy, mechanical strength, and thermal conductivity.

The inorganic foam particles (a21) may have an average particle diameter of 10 to 1,000 ㎛. If the average particle diameter is less than 10㎛, the volume expansion rate is low, it can not act as a char forming agent, the desired flame retardancy can not be obtained, and if the average particle diameter exceeds 1,000 ㎛ it is not possible to obtain the desired mechanical strength and thermal conductivity. Preferably it is 100-750 micrometers, More preferably, it is 150-500 micrometers. Thus, when the expanded graphite having a relatively small particle size is applied, the stability of the suspension is better than that of the expanded graphite having a larger particle size, and the internal water content of the prepared particles can be significantly lowered.

The expanded graphite can be prepared by inserting intercalated chemical species between layered crystal structures of graphite and then heat-treating or microwaving the expanded graphite. In the specific example, graphite is treated with an oxidizing agent to introduce intercalation compounds such as SO ₃ ^{2 -} and NO ₃ ^- into the graphite layers, and the graphite formed with such intercalation compounds is rapidly heated or irradiated with microwaves, The combined chemical species can be produced by gasifying and then expanding the graphite by several hundreds to thousands times by the pressure, and it is easy to purchase commercially.

In the present invention, expanded graphite expanded at 150 ° C. or higher is used. If the expansion temperature is less than 150 ℃ the expanded graphite particles may be deformed or broken during the polymerization reaction can not be expected as a char former (char former). Preferably, expanded graphite that expands at 250 ° C. or higher, more preferably 300 ° C. or higher is used.

The silicate may be an organic layered silicate, preferably sodium silicate, lithium silicate and the like. In the present invention, the silicate forms a char to form a barrier film to maximize flame retardancy. Such organic layered silicates are organically modified clays such as smectite, kaolinite, and illite. As the clay, for example, montmorillonite, hectorite, saponite, vermiculite, kaolinite, hydromica, and the like can be used. An alkylamine salt or an organic phosphate may be used as the modifier for organicizing the clay, and a didodecyl ammonium salt, a tridodecyl ammonium salt, etc. may be used as the alkylamine salt, and the organic phosphate may be tetrabutyl phosphate, tetraphenyl phosphate, Triphenyl hexadecyl phosphate, hexadecyl tributyl phosphate, methyl triphenyl phosphate, ethyl triphenyl phosphate, etc. can be used. The alkylamine salt or organophosphate is substituted with the interlayer metal ions of the layered silicate to increase the interlayer distance, and the physical properties of the layered silicate are changed to be affinity with the organic material to enable kneading with the resin.

In the specific example, montmorillonite modified with an alkylamine salt of C ₁₂ -C ₂₀ may be used as the organically modified layered silicate. In embodiments, the organo-modified montmorillonite (hereinafter abbreviated as m-MMT) can be organically intercalated with dimethyl dihydrogenated tallow ammonium instead of Na +.

The pearlite may be a heat-treated expanded pearlite. When the pearlite is heated to about 870 to 1100 ° C, the evaporation pressure generated by the vaporization of the volatile component including moisture causes each granule particle to expand to about 10 to 20 times the circular glassy particles .

In an embodiment, the expanded pearlite may have a specific gravity of 0.04 to 0.2 g / cm < ² >.

The white yarn may be a foamed white yarn.

In the present invention, the inorganic foam particles (a21) may be used in 3 to 29% by weight of 100% by weight of (a11) + (a12) + (a21) + (a22). Excellent polymerization stability in the above range, excellent incombustibility can be obtained. Preferably it may be included in 8 to 25% by weight.

The carbon filler a22 may be graphite, carbon black, carbon fiber, carbon nanotube, or the like, but is not necessarily limited thereto.

The carbon filler (a22) may be in the form of particles, fibers, flakes, amorphous, and the like, of which particles are preferably particles.

In an embodiment, the (a22) carbon filler may have an average particle diameter of 0.1 to 100 μm. There is an advantage of excellent polymerization stability in the above range. Preferably the average particle diameter is 1-50 micrometers, More preferably, it is 1-30 micrometers.

In the present invention, the carbon filler (a22) may be used in 0.01 to 30% by weight of (a11) + (a12) + (a21) + (a22) 100% by weight. It is excellent in polymerization stability in the said range, and excellent heat insulation can be obtained. Preferably it may be included in 0.5 to 20% by weight, for example 1 to 10% by weight.

In one embodiment, the weight ratio between the inorganic foam particles (a21) and the carbon filler (a22) may be 5: 1 to 50: 1, preferably 10: 1 to 30: 1. It has more excellent heat insulation and nonflammability in the above range.

Preparing a dispersion by mixing the (a11) styrene monomer, (a12) char-generating thermoplastic resin, (a21) inorganic foam particles and (a22) carbon filler, and then polymerizing the dispersion. Can be. Suspension polymerization may be preferably applied to the polymerization.

The dispersion may further include a conventional additive. Examples of the additive include antiblocking agents, nucleating agents, antioxidants, carbon particles, fillers, antistatic agents, plasticizers, pigments, dyes, heat stabilizers, UV absorbers and flame retardants. These additives may be used alone or in combination.

It is also possible to add customary auxiliaries, such as peroxide initiators, suspension stabilizers, blowing agents, chain transfer agents, expansion aids, nucleating agents and the like, during suspension polymerization. The adjuvants may be included in the dispersion.

The antiblocking agent can be selectively used so that the particles adhere to each other at the time of foaming or can be easily fused at the time of heat insulating material production. For example, an ethylene-vinyl acetate copolymer may be used.

As the nucleating agent, polyethylene wax may be used.

Examples of the flame retardant include phosphorus-based flame retardants such as tris (2,3-dibromopropyl) phosphate, triphenylphosphate, and bisphenol A diphenyl phosphate, or halogen-based flame retardants such as hexabromocyclododecane and tribromophenyl allyl ether. It may be used, preferably bisphenol di diphenyl phosphate may be used.

As the suspension stabilizer, it is advantageous to use an inorganic pickling dispersant such as magnesium pyrophosphate or calcium phosphate.

The polymerization reaction thus forms a bead-shaped, essentially round particle core (A) in the range of 0.5 to 3 mm.

Secondary polymerization

In the second polymerization step, a monomer having a glass transition temperature of 120 ° C. or less is added to the core (A) prepared in the first polymerization and polymerized to form a skin layer (B).

The monomer introduced into the secondary polymerization has a glass transition temperature of 120 ° C. or lower, and preferably a glass transition temperature of 80-120 ° C. In embodiments, at least one monomer selected from the group consisting of styrene and alphamethyl styrene may be added to the secondary polymerization. Among these, preferably styrene.

The monomer having a glass transition temperature of 120 ° C. or less is added in an amount of 5 to 25 parts by weight, preferably 7 to 20 parts by weight, and more preferably 10 to 15 parts by weight based on 100 parts by weight of the core (A). Can have excellent nonflammability and heat insulation performance in the above range, and is excellent in compression strength and flexural strength.

The secondary polymerization may be carried out suspension polymerization, emulsion polymerization, and the like, preferably suspension polymerization.

In one embodiment, the core (A) obtained in the first polymerization and the monomer having a glass transition temperature of 120 ° C. or lower may be added to the dispersion liquid in which the suspension stabilizer is dispersed, and the initiator may be concentrated.

In embodiments, the dispersion may be prepared by stirring 0.001 to 1.0 parts by weight of sodium pyrophosphate (10 hydrochloride) Na ₄ P ₂ O ₇ 10 H ₂ O and 0.001 to 1.0 parts by weight of magnesium chloride (MgCl ₂ ) in 100 parts by weight of ultrapure water. Can be.

As the emulsifying agent, a conventional one can be used, for example, sodium benzoate (DSM COMPANY), tricalcium phosphate (BUNDENHEIM C13-08) and the like can be used.

In addition, in the second polymerization, conventional additives added in the first polymerization may be added to stabilize the reaction or further improve physical properties.

The blowing agent can then be added before, during or after the second polymerization.

The blowing agent is well known in the art, C _{3 - 6} hydrocarbon, for example propane, butane, isobutane, n- pentane, isopentane, neopentane, cyclopentane, hexane, cyclohexane; Halogenated hydrocarbons such as trichlorofluoromethane, dichlorofluoromethane, dichlorotetrafluoroethane and the like can be used. Preference is given to double butane, pentane and hexane.

In the present invention, the blowing agent may be included in 3 to 10 parts by weight based on 100 parts by weight of the core (A). There is an advantage in that it has good processability in the above range.

As described above, the secondary polymerized particles have an average particle size of about 0.5 to 5 mm, and have a core (A) and a skin layer (B) structure formed on the core surface. 1 is a schematic cross-sectional view of a non-flammable expanded polystyrene-based polymerized bead according to one embodiment of the present invention. As shown, the incombustible expanded polystyrene-based polymerized beads of the present invention have a structure of a core (A) and a skin layer (B) surrounding the core (A). The skin layer may cover all or part of the core surface.

The core (A) is formed by polymerizing (a11) a styrene monomer, (a12) char-forming thermoplastic resin, (a21) inorganic foam particles, and (a22) carbon filler, (a11) a styrene monomer and (a12). ) Char-generating thermoplastic resin forms a continuous phase (a1), and (a21) inorganic foam particles and (a22) carbon filler have a structure dispersed in the continuous phase (a1).

 In the skin layer (B), a monomer having a glass transition temperature of 120 ° C. or less is polymerized to form a resin (4), and surrounds the core (A). In embodiments, the skin layer (B) 20 may continuously wrap the core (A) and may be discontinuously wrapped. Preferably 90 to 100% of the surface area of the core (A). In addition, the core (A) and the skin layer (B) has a structure in which the blowing agent (2) is impregnated.

In embodiments, the ratio of the radius of the core (A) and the thickness of the skin layer (B) may be 1: 0.0001 ~ 1: 0.2. In this range, it is advantageous in that the mechanical properties are excellent and the molding is easy.

In addition, the weight ratio of the core (A) and the skin layer (B) may be 1: 0.035 ~ 0.23. In this range, it is advantageous in that the mechanical properties are excellent and the molding is easy.

Another aspect of the invention provides a non-combustible polystyrene foam prepared using the non-combustible expanded polystyrene-based polymerized beads.

The foam formed from the non-combustible expanded polystyrene-based polymerized beads was prepared using a 550 mm thick sample with a radiant heat of 50 mm thick according to KS F ISO 5660-1 and a 50 kW / The heat release rate (THR) after heating for 5 minutes at m 2 is less than 0.9 kW / m 2, preferably 0.3-0.88 kW / m 2.

In addition, the compressive strength according to KS M 3808 is 19 N / cm ² Above, for example, the compressive strength is 19 ~ 30 N / cm ² Flexural strength is 37.6 N / cm ² Or more.

In addition, the foam has a thermal conductivity of 0.033 W / m · K or less, and a fusion rate of 20 to 60%, preferably 25 to 60%.

The foam of the present invention can be applied to packaging materials for home appliances, agricultural and marine products boxes, house insulation materials, etc., and is suitably applied as a core material of a sandwich panel manufactured by inserting a heat insulating material core between a house insulation material and an iron plate, .

The invention can be better understood by the following examples, which are intended to illustrate the invention and are not intended to limit the scope of protection defined by the appended claims.

Example

Example  One

(1) Primary Polymerization-Core (A) Preparation

79 parts by weight of styrene monomer and 3 parts by weight of polyphenylene ether (MEX PX100F), 15 parts by weight of expanded graphite (ADT MPH803) having an average particle size of 180 µm or more, and a graphite having an average particle size of 6 µm (TIMCAL S- 249) 3 parts by weight, 0.3 part by weight of benzoyl peroxide, 0.1 part by weight of t-butylperoxybenzoate, 0.55 part by weight of hexabromo cyclododecane, and 0.01 part by weight of sodium alkylbenzenesulfonate were added and stirred for 60 minutes. Thereafter, 100 parts by weight of ultrapure water and 0.3 part by weight of tricalcium phosphate were added to the 100L reactor, followed by stirring for 30 minutes. After incorporating the organic phase obtained above into a 100 L reactor, the suspension was rapidly heated to 90 ° C. and held at 90 ° C. for 4 hours to obtain a primary polymer.

(2) Secondary polymerization-skin layer (B) formation

100 parts by weight of ultrapure water was prepared by stirring sodium pyrophosphate (10 hydrochloride) Na ₄ P ₂ O ₇ · 10H ₂ O 0.8 parts by weight and 0.9 parts by weight of magnesium chloride, followed by the primary polymerization (A) 100 Part by weight was added and the temperature was maintained at 60 ° C. 0.3 parts by weight of dicumyl peroxide as an initiator and 0.3 part by weight of t-butyl peroxybenzoate were dissolved in 15 parts by weight of a styrene monomer, and then charged at a constant rate for about 30 minutes in order to keep the dispersion system stable. Lt; RTI ID = 0.0 > 125 C. < / RTI > 8 parts by weight of a pentane mixed gas was added thereto, and the mixture was maintained at a temperature of 125 DEG C for 6 hours to prepare expandable polystyrene. After drying for 5 hours, the coated foamed polystyrene beads were put into a flat plate molding machine, and a desired molded foam article was produced at a steam pressure of 0.5 kg / cm 2.

Thereafter, it was dried in a drying room at 50 캜 for 24 hours, and cut to prepare a test piece for property measurement.

The properties of the prepared test pieces were measured by the following methods.

How to measure property

(1) Nonflammability: Flame retardancy test was carried out according to KS F ISO 5660-1. After heating for 5 minutes, total heat release (THR), heat release rate (HRR: Heat Release Rate, kW / ㎡) and crack occurrence were examined.

(2) Thermal conductivity (W / m · K): The specific gravity of the sample was 30 kg / m 3, and the thermal conductivity of the insulating material specified in Korean Industrial Standard KS L 9016 was measured.

(3) Compressive Strength (N / cm ² ): Measured according to the method of measuring the compressive strength of a foamed polystyrene insulating material specified in Korean Industrial Standards KS M 3808 at a specific gravity of 30 kg / m 3.

(4) Flexural Strength (N / cm ² ): Measured according to the method of measuring the flexural strength of the expanded polystyrene insulation material specified in Korean Industrial Standard KS M 3808 at a specific gravity of 30 kg / m 3.

(5) Fusion rate (%): Percentage of the total number of particles on the cut surface versus the number of particles invisible to the skin layer was determined.

Example  2

Except for changing the content of the styrene monomer from 15 parts by weight to 10 parts by weight in the second polymerization step was carried out in the same manner as in Example 1.

Example  3

Except for changing the content of the styrene monomer in the second polymerization step from 15 parts by weight to 7.5 parts by weight was carried out in the same manner as in Example 1.

Comparative Example  One

A core (A) was prepared in the same manner as in Example 1, and then stirred in 100 parts by weight of ultrapure water in 0.8 parts by weight of sodium pyrophosphate (10 hydrochloride) Na ₄ P ₂ O ₇ · 10H ₂ O and 0.9 parts by weight of magnesium chloride. After the preparation, 100 parts by weight of the core (A) prepared above was added thereto, and the temperature was raised to a temperature range of 125 ° C. 8 parts by weight of a mixed gas of pentane gas was added thereto, and the mixture was maintained at a temperature of 125 DEG C for 6 hours to prepare expandable polystyrene.

Comparative Example  2

Except for changing the content of the styrene monomer from 15 parts by weight to 1.5 parts by weight in the second polymerization step was carried out in the same manner as in Example 1.

Comparative Example  3

Except for changing the content of the styrene monomer in the second polymerization step from 15 parts by weight to 30 parts by weight was carried out in the same manner as in Example 1.

Comparative Example  4

Except for changing the content of the styrene monomer in the second polymerization step from 15 parts by weight to 50 parts by weight was carried out in the same manner as in Example 1.

Example Comparative Example One 2 3 One 2 3 4 (a11) styrene monomer 79 79 79 79 79 79 82 (a12) Char production resin 3 3 3 3 3 3 - (a21) inorganic foam particles 15 15 15 15 15 15 15 (a22) Carbon filler 3 3 3 3 3 3 3 Monomer content in the skin layer (B) formation step
(Parts by weight) 15 10 7.5 0 1.5 30 15 KS F
ISO
5660
-One Peak-HRR 2.19 2.17 2.18 2.18 2.19 2.20 2.29 THR 0.89 0.86 0.83 0.90 0.91 0.97 0.99 Exterior No crack No crack No crack No crack No crack Cracked Cracked Thermal conductivity 0.032 0.031 0.031 0.031 0.033 0.033 0.034 Compressive strength 19.7 19.3 19.1 17.7 18.0 18.7 19.7 Flexural strength 38.2 38.1 37.9 37.2 37.2 37.5 37.4 Fusion rate (%) 38 32 29 5 6 50 46

As shown in Table 1, Examples 1 to 3 it was confirmed that the mechanical strength, such as bending strength, compressive strength due to fusion increased compared to the comparative example. In Comparative Example 1 in which the skin layer B was not formed, the compressive strength and the flexural strength were considerably lowered, and the fusion rate was also lowered. As in Comparative Example 3-4, when the amount of the styrene monomer increased to a certain amount or more, it was found that the flame retardancy of the resin itself decreased. In addition, in Comparative Example 4 in which the char-generating thermoplastic resin was not included in the mixed resin, char was not generated at all after combustion and exhibited a characteristic of being dispersed like dust powder.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. As will be understood by those skilled in the art. It is therefore to be understood that the embodiments described above are in all respects illustrative and not restrictive.

a21: inorganic foam particle a22: carbon filler
2: blowing agent a1: continuous phase
4: Glass transition temperature 120 占 폚 or less Resin
A: Core B: Skin Layer
100: expanded polystyrene beads

Claims (22)

a core (A) is prepared by first polymerizing (a11) a styrene monomer, (a12) a char-generating thermoplastic resin, (a21) inorganic foam particles, and (a22) a carbon filler; And
Injecting a monomer having a glass transition temperature of 120 ° C. or lower into the core (A) and performing secondary polymerization to form a skin layer (B) on the particle surface;
Method for producing a non-flammable expanded polystyrene-based polymerized beads comprising the step.

According to claim 1, wherein the core (A) is (a11) 65 to 95% by weight of the styrenic monomer, (a12) 1 to 10% by weight of char-forming thermoplastic resin, (a21) 3 to 29 weight of the inorganic foam particles % And (a22) 0.01 to 30% by weight of carbon filler polymerized.
The method according to claim 1, wherein the monomer having a glass transition temperature of 120 ° C. or less is added in an amount of 5 to 25 parts by weight based on 100 parts by weight of the core (A).
The method of claim 1, wherein the char-generating thermoplastic resin has an oxygen bond, an aromatic group, or a combination thereof in a main chain thereof.
The method of claim 1, wherein the char-generating thermoplastic resin is at least one selected from the group consisting of polycarbonate, polyphenylene ether, polyurethane, polyphenylene sulfide, polyester, polyimide.
The method of claim 5, wherein the char-generating thermoplastic resin is selected from the group consisting of polycarbonate, polyphenylene ether, and polyurethane resin.
The method of claim 1 wherein the inorganic foam particles are selected from one or more of the group consisting of expanded graphite, silicate, pearlite and white sand.
The method of claim 1, wherein the inorganic foam particles have an average particle diameter of 10 to 1,000 ㎛, characterized in that the expansion temperature is 150 ℃ or more.
The method of claim 1, wherein the carbon filler is selected from the group consisting of graphite, carbon black, carbon fiber, and carbon nanotubes.
The non-flammable expanded polystyrene bead according to claim 1, wherein the carbon filler has an average particle diameter of 0.1 to 100 µm.
The method of claim 1, wherein the monomer having a glass transition temperature of 120 ° C. or less is selected from the group consisting of styrene and alphamethyl styrene.
The method according to claim 1, wherein the core (A) is subjected to secondary polymerization after a monomer and a blowing agent having a glass transition temperature of 120 ° C. or less are added thereto.
The method according to claim 1, wherein the blowing agent is added during the secondary polymerization to polymerize.
The method according to claim 1, wherein the blowing agent is added after the secondary polymerization.
The method of claim 1, wherein at least one selected from the group consisting of antiblocking agents, nucleating agents, antioxidants, carbon particles, fillers, antistatic agents, plasticizers, pigments, dyes, heat stabilizers, UV absorbers and flame retardants during the primary or secondary polymerization The method characterized in that the polymerization by adding an additive to be.
A non-flammable expanded polystyrene-based polymerized bead formed by the method of any one of claims 1 to 15 and having a core (A) and a skin layer (B) structure formed on the core surface.
a core (A) formed by polymerizing (a11) a styrene monomer, (a12) a char-generating thermoplastic resin, (a21) inorganic foam particles, and (a22) a carbon filler; And
A skin layer (B) formed on the surface of the core (A) and formed by polymerizing a monomer having a glass transition temperature of 120 ° C. or less;
The non-combustible expanded polystyrene-based polymerized beads having a structure in which the core (A) and the skin layer (B) are impregnated with a blowing agent.
The method according to claim 17, wherein the core (A) is (a11) 65 to 95% by weight of the styrenic monomer, (a12) 1 to 10% by weight of char-forming thermoplastic resin, (a21) 3 to 29 weight of the inorganic foam particles % And (a22) 0.01 to 30% by weight of carbon filler polymerized, incombustible expanded polystyrene polymerized beads.
18. The non-flammable expanded polystyrene-based polymerized bead according to claim 17, wherein the ratio of the radius of the core (A) and the thickness of the skin layer (B) is 1: 0.0001 to 1: 0.2.
18. The non-combustible expanded polystyrene-based polymerized beads according to claim 17, wherein the non-combustible expanded polystyrene-based polymerized beads have an average particle diameter of 0.5 to 5 mm.
18. The non-flammable expanded polystyrene-based polymerized beads according to claim 17, wherein the weight ratio of the core (A) and the skin layer (B) is 1: 0.035-1: 0.23.
23. The heat release rate (THR) is 0.9 after a 50 mm thick sample is heated for 5 minutes at 50 kW / m 2 radiant heat of a cone heater according to KS F ISO 5660-1. Less than kW / ㎡, compressive strength of 19 N / cm ² by KS M 3808 Above, bending strength is 37.6 N / cm ² The non-combustible polystyrene foam characterized by the above-mentioned, and the fusion rate is 20 to 60%.

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