KR101411011B1 - Non flammable expandable polystyrene polymerized beads and method for preparing the same - Google Patents

Abstract

The non-combustible foamed polystyrene bead of the present invention comprises a core (A) comprising a styrene type resin (a1), a char forming thermoplastic resin (a2), an inorganic foam (a3), and a carbon filler (a4); And a skin (B) formed on the surface of the core (A) and comprising a resin having a glass transition temperature of 120 DEG C or lower, wherein the core (A) or the skin (B) contains a foaming agent . The foam produced from the incombustible foamed polystyrene beads of the present invention exhibits nonflammability, heat insulation performance and excellent mechanical strength over KS F ISO 5660-1, flame retardant material (grade 3 of flame retardancy) and not self-extinguishing flame retardant.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a non-flammable expanded polystyrene beads,

The present invention relates to an incombustible foamed polystyrene bead and a process for producing the same. More specifically, the present invention relates to a method for producing a carbon fiber-reinforced thermosetting resin composition, which comprises forming a skin with a resin having a glass transition temperature of 120 ° C or less in a core into which a char-generating thermoplastic resin, an inorganic foam and a carbon filler are introduced into a styrene- To a non-combustible expanded polystyrene beads and a process for producing 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 a foamed polystyrene bead having excellent nonflammability over a flame retardant material in KS F ISO 5660-1, which is not a self-extinguishing flame retardant, and a method for producing the same.

Another object of the present invention is to provide a non-combustible foamed polystyrene bead exhibiting excellent nonflammability, heat insulation performance and excellent mechanical strength and a method for producing the same.

Another object of the present invention is to provide a non-combustible foamed polystyrene bead which can be manufactured with little facility investment without causing environmental pollution and a method for producing the same.

It is still another object of the present invention to provide a non-combustible foamed polystyrene bead having excellent processability and a process for producing the same.

It is still another object of the present invention to provide a method for obtaining a non-combustible foamed polystyrene bead having a desired size at a high yield.

It is still another object of the present invention to provide a non-combustible foamed polystyrene bead which can increase the content of carbon particles and does not require a separate screening step, and a method for producing the same.

It is still another object of the present invention to provide a flame retarded polystyrene foam using the nonflammable expanded polystyrene beads.

Another object of the present invention is to provide a fire-retardant polystyrene foam which is excellent in balance of non-flammability, thermal conductivity and mechanical strength using the non-combustible foamed polystyrene beads, and is suitable for building materials such as sandwich panels and the like.

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 non-combustible foamed polystyrene beads. The non-combustible foamed polystyrene bead includes a core (A) comprising a styrene type resin (a1), a char forming thermoplastic resin (a2), an inorganic foam (a3), and a carbon filler (a4); And a skin (B) formed on the surface of the core (A) and comprising a resin having a glass transition temperature of 120 DEG C or lower, wherein the core (A) or the skin (B) contains a foaming agent .

In an embodiment, the skin (B) is characterized in that the inorganic foam (a3) or the carbon filler (a4) is absent.

In one embodiment, the skin (B) may wrap a portion of the core surface.

In another embodiment, the skin (B) may wrap the entire surface of the core.

The surface of the nonflammable expanded polystyrene bead is composed of a resin having a glass transition temperature of 120 DEG C or lower and a blowing agent impregnated in the resin, and the char forming thermoplastic resin, the inorganic foam (a3) and the carbon filler (a4) .

In an embodiment, the mixed resin comprises (a1) 90 to 99% by weight of a styrene resin; And (a2) 1 to 10% by weight of a char-generating thermoplastic resin.

The styrene resin (a1) may have a weight average molecular weight of 180,000 to 300,000 g / mol.

The char-generating thermoplastic resin may have an oxygen bond, an aromatic group, or a combination thereof in the main chain. In an embodiment, the char-generating thermoplastic resin may be at least one selected from the group consisting of polycarbonate, polyphenylene ether, polyurethane, polyphenylene sulfide, polyester, and polyimide. Preferably, the char-generating thermoplastic resin may be selected from the group consisting of polycarbonate, polyphenylene ether, and polyurethane resin.

The inorganic foam may be selected from the group consisting of expanded graphite, silicate, pearlite and white yarn.

The inorganic foam may have an average particle diameter of 170 to 1,000 占 퐉 and an expansion temperature of 200 占 폚 or higher.

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.

In embodiments, the resin having a glass transition temperature of 120 캜 or less may be a general purpose polystyrene (GPPS), a high impact polystyrene (HIPS), an acrylonitrile-butadiene-styrene copolymer (ABS), a styrene- acrylonitrile copolymer A styrene-methyl methacrylate copolymer, a styrene-based resin such as a blend of polymethylmethacrylate and a styrene resin, and the like can be used.

The nonflammable expanded polystyrene beads may further contain additives such as an antiblocking agent, a nucleating agent, an antioxidant, carbon particles, a filler, an antistatic agent, a plasticizer, a pigment, a dye, a heat stabilizer, a UV absorbent and a flame retardant.

In an embodiment, the ratio of the radius of the core (A) to the thickness of the skin (B) may be 1: 0.0001 to 1: 0.2.

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

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

Another aspect of the invention relates to a nonflammable polystyrene based foam. The foam was formed by foaming the beads and a 50 mm thick sample was heated for 5 minutes at a radiant heat of 50 kW / m < 2 > of the cone heater according to KS F ISO 5660-1, and the total heat release rate (THR) was less than 0.9 MJ / , The thermal conductivity by KS L 9016 is 0.032 W / m · K or less, the compressive strength by KS M 3808 is 19 N / cm ² Or more and a fusion ratio of 20 to 60%.

Another aspect of the present invention relates to a method for producing a non-combustible foamed polystyrene bead. The method comprises the steps of mixing (A) a styrene resin, (a2) a char forming thermoplastic resin, (a3) an inorganic foam and (a4) a carbon filler, To prepare a dispersion; And polymerizing the dispersion.

The dispersion may contain 5 to 30 parts by weight of a monomer having a glass transition temperature of 120 占 폚 or less with respect to 100 parts by weight of the core (A).

In one embodiment, the foaming agent may be added to the dispersion before polymerization.

In another embodiment, the foaming agent may be added during the polymerization to polymerize

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

The dispersion may contain at least one of an antiblocking agent, a nucleating agent, an antioxidant, a carbon particle, a filler, an antistatic agent, a plasticizer, a pigment, a dye, a heat stabilizer, a UV absorbent, a flame retardant, a peroxide initiator, a suspension stabilizer, a foaming agent, a chain transfer agent, And may further include additives.

The present invention relates to a flame-retardant flame retardant which is excellent in heat insulation and not self-extinguishing flame retardancy, has excellent flame retardancy as compared with a flame retardant material in KS F ISO 5660-1, has no need of further processing steps, has excellent productivity, has excellent incombustibility, A non-combustible foamed polystyrene bead capable of being produced with little facility investment without causing environmental pollution, having excellent processability, easy size control, and capable of increasing the content of carbon particles, and a process for producing the same. The present invention has the effect of providing a non-burned polystyrene foam suitable for building materials such as sandwich panels and the like because of excellent non-flammability, thermal conductivity and mechanical strength properties using expanded polystyrene beads.

1 is a schematic cross-sectional view of a non-combustible foamed polystyrene bead according to one embodiment of the present invention.

The non-combustible foamed polystyrene bead of the present invention comprises a core (A) comprising a styrene type resin (a1), a char forming thermoplastic resin (a2), an inorganic foam (a3), and a carbon filler (a4); And a skin (B) formed on the surface of the core (A), the skin (B) comprising a resin having a glass transition temperature of 120 DEG C or lower, and the core (A) or the skin (B) contains a foaming agent. The skin (B) may not contain the inorganic foam (a3) and the carbon filler (a4).

1 is a schematic cross-sectional view of a non-combustible foamed polystyrene bead according to one embodiment of the present invention. As shown, the non-combustible foamed polystyrene beads of the present invention comprise core (A); And a skin (B) surrounding the core surface.

Core (A)

The core (A) contains the inorganic foam (a3) and the carbon filler (a4) dispersed in the mixed resin (1) containing the styrene resin (a1) and the char forming thermoplastic resin (a2). In the mixed resin (1), a styrene-based resin and a char-generating thermoplastic resin are uniformly mixed to form a continuous phase.

In an embodiment, the mixed resin (1) comprises (a1) 90 to 99% by weight of a styrene resin; And (a2) 1 to 10% by weight of a char-generating thermoplastic resin.

The styrene-based resin (a1) may be a homopolymer of a styrene-based monomer, a copolymer of a styrene-based monomer and a monomer copolymerizable therewith, or a mixture thereof. In another embodiment, it may be a mixture of a styrene resin and another resin.

In one embodiment, the styrene resin (a1) may be a styrene resin having a weight average molecular weight of 180,000 to 300,000 g / mol. There is an advantage that excellent workability and mechanical strength are obtained when the heat insulating material is produced in the above range.

In a specific example, the styrene resin (a1) is a copolymer of general-purpose polystyrene (GPPS), high-impact polystyrene (HIPS) resin, styrene monomer and alpha -methylstyrene, acrylonitrile-butadiene- Acrylonitrile copolymer (SAN), a copolymer of styrene-methyl methacrylate, a blend of styrene resin and polymethyl methacrylate, and the like, but not always limited thereto. These may be used alone or in combination of two or more. Of these, general-purpose polystyrene (GPPS) and high-impact polystyrene (HIPS) resin resins are preferable.

The (a2) char generating thermoplastic resin may have an oxygen bond in the main chain or an aromatic group, or may have both an oxygen bond and an aromatic group.

Examples of the char generating thermoplastic resin (a2) include polycarbonate, polyphenylene ether, polyurethane, etc. These may be used singly or in combination of two or more. In other embodiments, polyester-based materials such as PPS, PET, and PBT, and polyimide may be used. These resins may be used alone or in combination of two or more.

In the specific examples, the polycarbonate may have a weight average molecular weight of 10,000 to 30,000 g / mol, 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 (a2) may be used in an amount of 1 to 10% by weight of the mixed resin containing (a1) + (a2). If char forming thermoplastic resin (a2) is used in an amount of less than 1 part by weight, flame retardation may be lowered due to lowering of Char occurrence. If it exceeds 10 parts by weight, mechanical properties are deteriorated due to high glass transition temperature .

The inorganic foam particles (a3) are at least one selected from the group consisting of expanded graphite, silicate, pearlite, and white yarn.

In the present invention, the inorganic foam (a3) acts as a char former. Therefore, it is required to maintain the shape without breakage when the resin is melt-extruded, and it is required to have a certain size in order to satisfy the incombustibility, mechanical strength and thermal conductivity.

The inorganic foam (a3) may have an average particle diameter of 170 to 1,000 占 퐉. If the average particle diameter is less than 170 탆, the volume expansion rate is low, which can not act as a char forming agent, and desired incombustibility can not be obtained. If the average particle diameter exceeds 1,000 탆, desired mechanical strength and thermal conductivity can not be obtained. Preferably 200 to 750 占 퐉, and more preferably 300 to 650 占 퐉.

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 expanding at 200 DEG C or higher is used. If the expansion temperature is less than 200 캜, expanded graphite particles may be deformed or broken during melt extrusion of the resin, and thus it can not be expected to act as a char former. Expanded graphite which expands at 250 DEG C or higher, more preferably 265 DEG C or higher, and most preferably 300 DEG C or higher is used.

Organic layered silicate may be used as the silicate, preferably sodium silicate, lithium silicate, or the like. In the present invention, the silicate forms a char to form a barrier film to maximize the incombustibility. Such an organophilic layered silicate is one modified by organizing clay such as smectite series, kaolinite series, illite series and the like. As the clay, for example, montmorillonite, hectorite, saponite, vermiculite, kaolinite, hyromicas and the like can be used. As the modifier for organizing the clay, an alkylamine salt or an organic phosphate can be used. As the alkylamine salt, it is possible to use a didodecylammonium salt, a tridodecylammonium salt and the like, and the organic phosphate is tetrabutylphosphate, tetraphenylphosphate, Triphenylhexadecyl phosphate, hexadecyl tributyl phosphate, methyl triphenyl phosphate, ethyl triphenyl phosphate and the like can be used. The alkylamine salt or the organic phosphate is substituted with the interlayer metal ion of the layer silicate to open the interlayer distance, and the physical properties of the layer silicate may be changed so as to have 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 (a3) may be used in an amount of 3 to 50 parts by weight based on 100 parts by weight of (a1) + (a2) mixed resin. In the above range, it is possible to have good balance of workability and nonflammable performance.

The carbon filler (a4) may be graphite, carbon black, carbon fiber, or carbon nanotube, but is not limited thereto.

The shape of the carbon filler (a4) may be a particle shape, a fiber shape, a tubular shape, a flake shape, an amorphous shape or the like, and preferably a particle shape.

In an embodiment, the carbon filler (a4) may have an average particle diameter of 0.1 to 100 mu m. The droplet of the polymer is easily retained within the above range, and the average particle diameter is preferably 1 to 50 mu m, more preferably 1 to 30 mu m.

In the present invention, the carbon filler (a4) may be used in an amount of 0.01 to 30 parts by weight based on 100 parts by weight of the (a1) + (a2) mixed resin. And has good processability and heat insulation in the above range. Preferably 1 to 20 parts by weight, for example, 1.5 to 10 parts by weight.

In one embodiment, the weight ratio between the inorganic foam (a3) and the carbon filler (a4) may be 5: 1 to 50: 1, preferably 10: 1 to 30: And has better heat insulating property and nonflammability in the above range.

skin

A skin (B) is formed on the outside of the core (A).

The skin (B) can continuously cover the core (A) and can be wound discontinuously. Preferably 90 to 100% of the surface area of the core (A).

The skin (B) comprises a resin (4) having a glass transition temperature of 120 ° C or lower, preferably a resin having a glass transition temperature of 80-120 ° C.

In a specific example, a styrene resin may be preferably used as the resin having a glass transition temperature of 120 ° C or lower. (ABS), styrene-acrylonitrile copolymer (SAN), styrene-butadiene-styrene copolymer (ABS), styrene-acrylonitrile copolymer ), A copolymer of styrene-methyl methacrylate, and a blend of styrene-based resin and polymethyl methacrylate. Particularly preferred are general-purpose polystyrene resins.

In one embodiment, the resin (4) having a glass transition temperature of 120 占 폚 or less may have a weight average molecular weight of 130,000 to 300,000 g / mol. In the above range, mechanical strength such as foamability, compressive strength and flexural strength is excellent.

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

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

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

The core (A) and the skin (B) have a structure in which the foaming agent (2) is impregnated.

The foaming agent (2) 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. Double pentane is most preferred.

In the present invention, the foaming agent may be used in an amount of 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.

The non-combustible foamed polystyrene beads may further include conventional additives. 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.

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 flame retardants such as tris (2,3-dibromopropyl) phosphate, triphenylphosphate and bisphenol a diphenylphosphate; halogen-based flame retardants such as hexabromocyclododecane and tribromophenyl allyl ether; And preferably bisphenol a diphenyl phosphate can be used.

Incombustible foam Polystyrene series Bead  Manufacturing method

Another aspect of the present invention relates to a method for producing a non-combustible foamed polystyrene bead.

Another aspect of the present invention relates to a method for producing a non-combustible foamed polystyrene bead. In an embodiment, the method comprises the steps of (a1) adding a styrene resin, (a2) a char generating thermoplastic resin, (a3) an inorganic foam and (a4) a carbon filler to the extruded core (A) Lt; 0 > C or less to prepare a dispersion; And polymerizing the dispersion.

In an embodiment, the core (A) comprises (a1) 90 to 99% by weight of a styrene resin; (A3) 3 to 50 parts by weight of an inorganic foam and (a4) 0.01 to 30 parts by weight of a carbon filler are mixed with 100 parts by weight of a mixed resin comprising (a2) 1 to 10% by weight of a char generating thermoplastic resin, .

The (a1) styrene resin may be in the form of pellets. That is, since conventional commercialized styrene resin pellets can be used, a separate styrene polymerization process is not required, and existing products can be utilized, which is economical and the process can be simplified. In a specific example, it may be a styrene resin pellet having a weight average molecular weight of 180,000 to 300,000 g / mol.

In one embodiment, the styrene resin pellets may contain a nucleating agent, an antioxidant, a carbon particle, a filler, an antistatic agent, a plasticizer, a pigment, a dye, a heat stabilizer, a UV absorber and a flame retardant. These additives may be used alone or in combination of two or more.

Thus, a mixed composition is prepared by mixing (a2) a char-generating thermoplastic resin and an inorganic foam in a first pellet containing a styrene-based resin.

Conventionally, an inorganic foam is coated on the outside of expanded particles or added during the polymerization process. However, when inorganic foams are added during the polymerization process, aggregation of particles or cracking occurs and the amount of addition can not be increased. And when the coating is carried out on the outside of the expanded particles, the strength of the final molded product is lowered. Therefore, in the present invention, by mixing the inorganic pellets with the first pellets obtained by completing the polymerization of styrene, it is possible to prevent agglomeration and breakage of the particles and prevent the strength of the final molded product from being lowered.

If necessary, conventional additives such as an antiblocking agent, a nucleating agent, an antioxidant, carbon particles, a filler, an antistatic agent, a plasticizer, a pigment, a dye, a heat stabilizer, a UV absorber and a flame retardant may be added to the mixed composition. These additives may be used singly or in combination of two or more.

Thus, the mixed composition in which the styrene resin, the char-generating thermoplastic resin, the inorganic foam and the carbon filler are mixed is extruded in an extruder to prepare a core (A) which is a second pellet.

There is no particular limitation on the extruder, but in order to obtain a desired grade, the die plate hole diameter is usually fixed to 0.7 to 2.0 mm, preferably 0.7 to 1.7 mm, more preferably 1.0 to 1.5 mm. The size of the second pellet thus produced is 2 mm or less, and a desired size is obtained at a high yield.

At this time, the extrusion temperature is controlled to 130 to 250 캜, preferably 150 to 200 캜.

The present invention is not only capable of increasing the content of carbon particles, but also eliminating the need for a separate sorting step, and achieving a grade of a desired size at a high yield by extruding the foaming agent before being charged. Further, it is possible to prevent the explosion due to the gas injection during the conventional extrusion.

A monomer having a glass transition temperature of 120 占 폚 or lower is introduced into the extruded core (A) and polymerized. In one embodiment, the monomer (A) having a glass transition temperature of 120 ° C or less and an initiator are added to the extruded core (A), the temperature is raised to 80-130 ° C, and then the foaming agent is introduced. After the foaming agent is added, it is preferable to maintain the temperature at 100 to 130 캜 for 1 to 8 hours.

The monomer having a glass transition temperature of 120 ° C or lower may be added in an amount of 5 to 30 parts by weight, preferably 10 to 25 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 amount of the blowing agent may be 3 to 10 parts by weight based on 100 parts by weight of the second pellets (core (A)) mixed with the mixed resin and the inorganic foam.

The dispersion may be prepared by stirring 0.001 to 1.0 part by weight of sodium pyrophosphate (10 hydrate) Na ₄ P ₂ O ₇ .10H ₂ O and 0.001 to 1.0 part by weight of magnesium chloride (MgCl ₂ ) in 100 parts by weight of ultrapure water.

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.

Further, it may further include usual additives during the polymerization or in the dispersion. 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.

The foamed polystyrene prepared as described above has pellets of a uniform size, so that a desired grade can be obtained at a yield of almost 100%.

In one embodiment, the non-combustible foamed polystyrene beads may have an average particle size of 0.5 to 5 mm.

Another aspect of the present invention provides an incombustible polystyrene foam produced using the nonflammable expanded polystyrene beads.

The foam formed from the non-combustible foamed polystyrene beads was prepared by heating a sample having a thickness of 550 mm for 5 minutes at a radiant heat of 50 kW / m 2 of a cone heater according to KS F ISO 5660-1, and a heat release rate (HRR) of less than 0.9 kW / Is 0.3 to 0.88 kW / m 2, and the fusion ratio is 20 to 60%, preferably 25 to 60%.

The thermal conductivity may be 0.033 W / m · K or less, and the compressive strength may be 19 to 30 N / cm ² Lt; / RTI >

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 present invention may be better understood by the following examples, which are for the purpose of illustrating the invention and are not intended to limit the scope of protection defined by the appended claims.

Example

Example  One

(1) Production of core (A)

5 parts by weight of polyphenylene ether (a2) (MEP PX100F) as a Char generating thermoplastic resin was added to 95 parts by weight of GPPS pellets (a1) (Cheil Industries GP HR-2390P00) having a weight average molecular weight of 270,000 g / 20 parts by weight of expanded graphite having an average particle size of 297 占 퐉 and an expansion temperature of 300 占 폚 (ADT Company MPH503) and 1.5 parts by weight of graphite having an average particle size of 6 占 퐉 (TIMCAL S-249) Extruded by a twin-screw extruder and pelletized.

(2) Skin formation

0.8 part by weight of sodium pyrophosphate (10 hydrate) Na ₄ P ₂ O ₇ .10H ₂ O and 0.9 part by weight of magnesium chloride were added to 100 parts by weight of ultrapure water in the reactor, and the extruded pellets (core A ) Was added thereto, and the temperature was maintained at 60 占 폚. 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

The procedure of Example 1 was repeated except that the content of styrene monomer was changed from 15 parts by weight to 7.5 parts by weight in the skin forming step.

Comparative Example  One

(Core (A)) was prepared in the same manner as in Example 1, and then 0.8 part by weight of sodium pyrophosphate (10 hydrate) Na ₄ P ₂ O ₇ .10H ₂ O and 0.9 part by weight of magnesium chloride were added to 100 parts by weight of ultrapure water , And then 100 parts by weight of the extruded pellets (core (A)) was added and the temperature was raised to 125 캜. 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

The procedure of Example 1 was repeated except that the content of styrene monomer was changed from 15 parts by weight to 1.5 parts by weight in the skin forming step.

Comparative Example  3

The procedure of Example 1 was repeated except that the content of styrene monomer was changed from 15 parts by weight to 50 parts by weight in the skin forming step.

Comparative Example  4

Except that 100 parts by weight of GPPS pellets (a1) was applied without applying a Char generating thermoplastic resin.

Example Comparative Example One 2 One 2 3 4 Core (A) Mixed resin (a1) PS 95 95 95 95 95 100 (a2) Char formation resin 5 5 5 5 5 - Mixed particle (a3) inorganic foam particles 20 20 20 20 20 20 (a4) Carbon filler 1.5 1.5 1.5 1.5 1.5 1.5 The monomer content in the skin-forming step
(Parts by weight) 15 7.5 0
(No skin) 1.5 50 15 KS F
ISO
5660
-One Peak-HRR 2.18 2.17 2.18 2.19 2.20 2.18 THR 0.88 0.84 0.90 0.93 0.97 0.92 Exterior No crack No crack No crack No crack Cracked Cracked Thermal conductivity 0.032 0.031 0.033 0.033 0.033 0.032 Compressive strength 19.6 19.2 17.7 18.0 18.7 18.2 Flexural strength 38.2 37.9 37.2 37.2 37.5 36.8 Fusion rate (%) 37 31 5 6 50 35

As shown in Table 1, it can be seen that Examples 1 and 2 have increased mechanical strength such as flexural strength and compressive strength due to fusion compared with Comparative Examples. In Comparative Example 1 in which the skins were not formed, the compressive strength and flexural strength were considerably lowered, and the fusion rate was also lowered. It was found that the flame retardancy of the resin itself decreased when the amount of the styrene monomer was increased more than a certain amount as in Comparative Example 3. [ In the case of Comparative Example 4 which does not contain a char forming thermoplastic resin in the mixed resin, the mechanical strength and the heat insulating property can be secured, but cracks are generated in the specimen after combustion and the performance as a fire resistant material is not exhibited.

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.

1: mixed resin 2: foaming agent
a3: inorganic foam a4: carbon filler
4: Glass transition temperature 120 占 폚 or less Resin
A: Core B: Skin
100: expanded polystyrene beads

Claims (25)

(A) comprising a mixed resin comprising a styrene-based resin (a1) and a char-generating thermoplastic resin (a2), an inorganic foamed material (a3), and a carbon filler (a4); And
A skin (B) formed on the surface of the core (A) and containing a resin having a glass transition temperature of 120 DEG C or lower,
Wherein the core (A) or the skin (B) contains a foaming agent,
Wherein the styrene-based resin (a1) has a weight average molecular weight of 180,000 to 300,000 g / mol, and the char generating thermoplastic resin (a2) has an oxygen bond, an aromatic group or a combination thereof in the main chain, (a3) is at least one selected from the group consisting of expanded graphite, silicate, pearlite and white yarn, and the carbon filler (a4) is at least one selected from the group consisting of graphite, carbon black, carbon fiber and carbon nanotube (GBPS), high impact polystyrene (HIPS) resin, acrylonitrile-butadiene-styrene copolymer (ABS), styrene-acrylonitrile copolymer Styrene-methyl methacrylate copolymer. The non-combustible foamed polystyrene beads according to claim 1,
The non-combustible foamed polystyrene bead according to claim 1, wherein the skin (B) is free of the inorganic foam (a3) or the carbon filler (a4).
The non-combustible foamed polystyrene bead according to claim 1, wherein the skin covers part or all of the core surface.
The method according to claim 1, wherein the surface of the nonflammable expanded polystyrene beads is composed of a resin having a glass transition temperature of 120 DEG C or lower and a blowing agent impregnated in the resin, wherein the char forming thermoplastic resin, inorganic foam (a3) (a4) is not present in the non-flammable expanded polystyrene beads.
[2] The method according to claim 1, wherein the mixed resin comprises (a1) 90 to 99% by weight of a styrene resin; And (a2) 1 to 10% by weight of a char-generating thermoplastic resin.
delete delete The method according to claim 1, wherein the char generating thermoplastic resin (a2) is at least one selected from the group consisting of polycarbonate, polyphenylene ether, polyurethane, polyphenylene sulfide, polyester and polyimide Non-combustible expanded polystyrene beads.
The non-combustible foamed polystyrene bead according to claim 8, wherein the char-generating thermoplastic resin (a2) is at least one selected from the group consisting of polycarbonate, polyphenylene ether, and polyurethane resin.
delete The non-combustible foamed polystyrene bead according to claim 1, wherein the inorganic foam (a3) has an average particle diameter of 170 to 1,000 占 퐉 and an expansion temperature of 200 占 폚 or more.
delete 2. The non-combustible foamed polystyrene bead according to claim 1, wherein the carbon filler (a4) has an average particle diameter of 0.1 to 100 mu m.
delete The non-combustible foamed polystyrene beads according to claim 1, wherein the non-combustible expanded polystyrene beads are at least one selected from the group consisting of antiblocking agents, nucleating agents, antioxidants, carbon particles, fillers, antistatic agents, plasticizers, pigments, dyes, heat stabilizers, The non-combustible foamed polystyrene beads according to claim 1, further comprising an additive.
The non-combustible foamed polystyrene bead according to claim 1, wherein the ratio of the radius of the core (A) to the thickness of the skin (B) is 1: 0.0001 to 1: 0.2.
The non-combustible foamed polystyrene bead according to claim 1, wherein the non-combustible foamed polystyrene beads have an average particle diameter of 0.5 to 5 mm.
The non-combustible foamed polystyrene bead according to claim 1, wherein the weight ratio of the core (A) to the skin (B) is 1: 0.035 to 1: 0.23.
A 50 mm thick sample formed by foaming the beads of any one of claims 1 to 5, 8, 9, 11, 13 and 15 to 18, wherein the sample is KS F (THR) of less than 0.9 MJ / m2, a thermal conductivity of 0.032 W / mK or less by KS L 9016 after heating for 5 minutes at a radiant heat of 50 kW / m 2 according to ISO 5660-1, and KS M 3808 of not less than 19 N / cm ² , and a fusion ratio of 20 to 60%.
(A) having a glass transition temperature of 120 占 폚 or less is formed by mixing (a1) a styrene resin, (a2) a char forming thermoplastic resin, (a3) an inorganic foam and (a4) Adding a monomer to prepare a dispersion; And
Polymerizing the dispersion; ≪ / RTI >
Wherein the styrene-based resin (a1) has a weight average molecular weight of 180,000 to 300,000 g / mol, and the char generating thermoplastic resin (a2) has an oxygen bond, an aromatic group or a combination thereof in the main chain, (a3) is at least one selected from the group consisting of expanded graphite, silicate, pearlite and white yarn, and the carbon filler (a4) is at least one selected from the group consisting of graphite, carbon black, carbon fiber and carbon nanotube (GBPS), high impact polystyrene (HIPS) resin, acrylonitrile-butadiene-styrene copolymer (ABS), styrene-acrylonitrile copolymer Styrene-methyl methacrylate, and a copolymer thereof with styrene-methyl methacrylate.
21. The method according to claim 20, wherein the dispersion is charged with 5 to 30 parts by weight of a monomer forming a resin having a glass transition temperature of 120 DEG C or lower per 100 parts by weight of the core (A).
21. The method according to claim 20, wherein the foaming agent is added to the dispersion, followed by polymerization.
21. The method according to claim 20, wherein the polymerization is carried out by introducing a foaming agent during the polymerization.
21. The method according to claim 20, wherein the foaming agent is introduced after the polymerization.
21. The method of claim 20, wherein the dispersion is selected from the group consisting of antiblocking agents, nucleating agents, antioxidants, carbon particles, fillers, antistatic agents, plasticizers, pigments, dyes, heat stabilizers, UV absorbers, flame retardants, peroxide initiators, And an additive selected from the group consisting of an additive, an additive, and an expansion aid.

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