KR20090044686A - Method for manufacturing expandable polystyrene particles with excellent flame retardancy - Google Patents

Abstract

The present invention relates to a method for producing expandable polystyrene particles comprising aluminum hydroxide particles. It is obtained by suspending expandable polystyrene particles in the form of suspensionable pellets containing aluminum hydroxide particles, followed by heating by blowing a blowing agent and a C 6 -C 10 aromatic hydrocarbon. Suspended pellets are polystyrene particles in the form of pellets containing aluminum hydroxide and having an L / D of 0.1-3.0 mm / 0.5-3.0 mm or a volume of 5 mm ³ or less. The expandable polystyrene particles obtained by this method form fine bubbles upon foaming and provide expandable polystyrene particles having heat insulation and excellent flame retardant properties.

Flame Retardant, Aluminum Hydroxide, Heat Insulation, Foam, Polystyrene

Description

Method for manufacturing expandable polystyrene particles with excellent flame retardancy

The present invention relates to a method for producing expandable polystyrene particles having excellent flame retardant properties, and more particularly, comprising suspending a suspensionable pellet containing aluminum hydroxide, followed by heating by adding a blowing agent and a C 6 -C 10 aromatic hydrocarbon. It relates to a method for producing expandable particles.

Polystyrene foams are generally pre-expanded foamable polystyrene particles to obtain pre-foamed granules, which are filled into a closed mold having a plurality of small holes, and then heated and foamed by pressurized steam to fill the voids between the foamed granules, After fusion to each other, it is produced by cooling and releasing from the mold.

The polystyrene foam is mainly used as a heat insulating material, sandwiched between the panels used in the wall of the building and the panel of the building, such as excellent flame retardancy, low thermal conductivity, low absorption rate, high strength is required. In particular, efforts have been made to improve the flame retardancy by adding various flame retardants to the expandable polystyrene particles and the foam in order to improve the flame retardancy of the heat insulating material.

As a way to improve the flame retardant performance of the insulation, a method of improving the flame retardancy by adding an organic bromine flame retardant, etc. to the synthetic resin foam polystyrene raw material manufacturing process and a method of maintaining the flame retardancy by coating the organic / inorganic flame retardant on the foamed polystyrene foam Have been in progress

So far, when added to the expanded polystyrene raw material particles in the above-described method, the flame retardancy is less than the flame retardant performance criteria (flame-retardant material; flame retardant class 3) of the interior finishing material of the building, and by adding a coating to the foamed polystyrene foam In addition, the manufacturing process is very complicated and the productivity is remarkably reduced, thus producing only a limited amount of production.

Therefore, it is a situation that the manufacturing method excellent in flame-retardant performance and productivity which are excellent as a heat insulating material is calculated | required, and it is preferable that this method consists of the raw material particle manufacturing method of native foamable polystyrene.

It is an object of the present invention to provide a new process for producing expandable polystyrene particles containing aluminum hydroxide particles.

It is an object of the present invention to provide a process for producing expandable polystyrene particles containing aluminum hydroxide using suspended polystyrene particles in the form of pellets comprising aluminum hydroxide.

Another object of the present invention is to provide a novel foam obtained by foaming of expandable polystyrene containing aluminum hydroxide particles having good physical properties such as low thermal conductivity, water absorption and strength and excellent flame retardancy.

The present invention for achieving the above object

Aqueous suspending the suspendable polystyrene pellets comprising aluminum hydroxide; And

Heating by adding a blowing agent and a C6-C10 hydrocarbon;

It consists of a method for producing a expandable polystyrene polymer containing aluminum hydroxide particles comprising a.

According to the present invention, a novel method for producing polystyrene particles containing aluminum hydroxide is provided. By foaming such polystyrene particles, it was possible to produce excellent foams that significantly improved flame retardancy while maintaining physical properties such as water absorption, strength, and thermal conductivity by sticking to the bubble diameter of existing polystyrene foams.

The process for preparing expandable polystyrene polymers containing aluminum hydroxide particles of the present invention comprises the steps of: aqueous suspension of suspendable polystyrene pellets comprising aluminum hydroxide; And heating the blowing agent and the C 6 -C 10 hydrocarbon; It includes.

In the present invention, the susceptible polystyrene pellets mean particles of a size that can be stably suspended by conventional aqueous suspension, etc., preferably L / D is 0.1 ~ 3.0mm / 0.5 ~ 3.0mm or volume Means polystyrene particles in the form of pellets of 5 mm ³ or less.

In the practice of the present invention, the extrusion is carried out using a single screw extruder or twin screw extruder to obtain particles of polystyrene in the form of suspended pellets comprising other additives, including aluminum hydroxide, under water cutting or water cooling. Pellets of this size can be obtained by cutting by the use of a die-face pelletizer and a hot cutting pelletizer (including the Kneader process).

In one embodiment of the invention, the polystyrene particles used for the production of pellets are styrene; Alkyl styrenes such as ethyl styrene, dimethyl styrene and para-methyl styrene; Alpha-alkylstyrenes such as alpha-methylstyrene, alpha-ethylstyrene, alpha-propylstyrene and alpha-butylstyrene; Halogenated styrenes such as chlorostyrene, and bromostyrene; And polymers and / or copolymers of styrene monomers composed of vinyl toluene, monomers copolymerizable with the styrene monomers, for example acrylonitrile, butadiene, alkyl acrylates, for example methyl acrylate, alkyl methacrylates, for example Copolymers with methyl methacrylate, isobutylene, vinyl chloride, isoprene and mixtures thereof.

In the present invention, aluminum hydroxide used for the production of pellets is introduced to improve flame retardancy. The aluminum hydroxide to be used may be synthesized aluminum hydroxide having a single material and compatibility, the particle size is preferably 0.1 ㎛ to 50 ㎛, particularly preferably 0.5 ㎛ to 10 ㎛ in order to increase the flame retardancy. In the present invention, the aluminum hydroxide particles are preferably used 10 to 70 parts by weight, more preferably 30 to 60 parts by weight based on 100 parts by weight of the styrene polymer.

In the present invention, the blowing agent used for the foaming of the polystyrene particles may be used a conventional blowing agent used for the expandable styrene polymer, preferably the blowing agent is added in 3 to 10 parts by weight based on 100 parts by weight of the polystyrene polymer. Suitable blowing agents may use aliphatic hydrocarbons having 4 to 6 carbon atoms, preferably a mixture of pentane and cyclopentane.

In the present invention, C6-C10 aromatic hydrocarbons are used to facilitate the solubility of the blowing agent to the polystyrene particles, to stabilize the foaming polystyrene particles over time and to improve the foamability, and to facilitate the spheroidization of the polystyrene particles in the form of pellets, based on the polystyrene particles Preference is given to using 0.1-1.0% by weight. When the amount of C6-C10 aromatic hydrocarbons is small, the foamability of the expandable polystyrene particles is reduced, spherical formation is difficult when using the pellet-type polystyrene particles, and if the amount of the aromatic hydrocarbons is too large, the heat resistance of the final molded product may be reduced. Can be.

The C6-C10 aromatic hydrocarbon may include benzene, toluene, p-xylene, o-xylene, m-xylene, ethylbenzene, propylbenzene, isopropylbenzene, etc., preferably toluene, ethyl benzene .

The polystyrene foam according to the present invention may include a bubble control agent to control the size of the bubble at the time of foaming. In polystyrene foam, bubble size plays an important role in mechanical properties and thermal insulation performance, and more specifically, when the bubble size is 300 μm or more, the thermal conductivity increases and the strength decreases due to gas convection inside the bubble. In a preferred embodiment of the present invention, the bubble control agent can be used in the process of extruding suspendable polystyrene pellets comprising aluminum hydroxide or in the impregnation process according to the invention. In one preferred embodiment of the present invention, as the bubble control agent, ethylene bis stearate, calcium carbonate, talc, clay, silica, barium stearate, diatomaceous earth, citric acid and sodium bicarbonate can be used, preferably 5 parts by weight or less. Is used in 3 parts by weight or less.

The polystyrene foams according to the invention can be introduced in the process of extruding suspending polystyrene pellets comprising aluminum hydroxide or in the impregnation process according to the invention for the purpose of improving flame retardancy. In one preferred embodiment of the invention, the flame retardant is hexabromo cyclododecane, tetrabromo cyclooctane, tetrabromo vinylcyclohexane, 2,2 '(4-allyloxy-3,5-dibromo Bromine flame retardants such as phenyl) propane and tribromophenyl allyl ether and conventional chlorine flame retardants can be used, and hexabromo cyclododecane is preferable.

In the present invention, the step of aqueous suspending suspendable polystyrene pellets comprising aluminum hydroxide can be carried out using conventional suspension methods, without particular limitation. In one embodiment of the invention, the pellet and suspending agent may be added to water and stirred. Suspensions may be used conventional suspensions used in the polystyrene polymerization process, there is no particular limitation.

In the present invention, the step of heating the blowing agent and the C6-C10 hydrocarbon is preferably heated by heating for about 3-12 hours at a temperature of 100-130 ℃. When the heating temperature is lowered, the softening capacity of polystyrene is lowered, so that it is not easy to add a blowing agent into the polystyrene, the pellet is difficult to be spherical, and when it is high, it causes dispersion instability and deteriorates the quality through decomposition of polystyrene and other additives including flame retardants. May cause.

Foams of expandable polystyrene containing aluminum hydroxide which increase thermal insulation properties such as low thermal conductivity, water absorption, and strength and excellent flame retardancy according to the present invention are obtained by heating a blowing agent and C6-C10 aromatic hydrocarbons into aqueous suspended polystyrene particles. Expandable polystyrene particles can be obtained by inclusion. The foaming conditions may use the conventional conditions used for the foaming of the expandable polystyrene, there is no particular limitation. Foams containing foamed aluminum hydroxide can be foamed by those skilled in the art to have a diameter of 30 to 200 microns, and have the advantage of excellent properties such as flame retardancy, heat conductivity, absorption rate and strength.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the Examples.

< Example 1 >

100% by weight of polystyrene (Kumho Petrochemical; HIPS 490FB) and 50% by weight of aluminum hydroxide were blended and melted in a biaxial molding machine at 200 ^° C., and the polystyrene containing aluminum hydroxide was extruded using an HOT CUTIING pelletizing machine to Pellets of 1.5 mm ³ to 5 mm ³ were obtained. Next, 100 parts by weight of polystyrene particles in a pellet form containing aluminum hydroxide, 100 parts by weight of pure water, 0.24 parts by weight of a suspending agent (tricalcium phosphate, Dubon Co .; DET-10), a flame retardant (hexabromocyclododecane, GLC; 0.35 parts by weight of CD75P ^™ ) was inserted into the reactor at room temperature, and the temperature was reacted at 70 ^° C. for 1 hour and 30 minutes. After completion of the temperature increase at 120 ^° C., 7 parts by weight of a blowing agent (pentane, SK) was added and maintained for 5 hours. The expanded polystyrene particles containing the aluminum hydroxide thus obtained were dehydrated and dried, followed by coating a blending agent to evaluate physical properties, and the results are shown in Table 1.

< Example 2 >

In order to understand the effect of the bubble control agent, 2 parts by weight of ethylenebisstearate (precursor) was introduced, 100 parts by weight of polystyrene (Kumho Petrochemical; HIPS 490FB) and 50 parts by weight of aluminum hydroxide were melted at 200 ^° C. in a biaxial molding machine. and HOT CUTTING pelletizer by using an extruded polystyrene containing aluminum hydroxide to obtain the pellets of an average volume of 1.5 mm ³ to 5mm ^3. Next, the impregnation process was the same as in <Example 1>, and the foamed polystyrene particles containing aluminum hydroxide were dehydrated and dried, followed by coating a blending agent to evaluate physical properties, and the results are shown in Table 1.

< Example 3 >

6 parts by weight of pentane (SK), cyclopentane (SK) by impregnating in the same manner using polystyrene particles of the same pellet form as in <Example 2> and varying the composition at 7 parts by weight of pentane (SK) Parts by weight were used. Next, after dewatering and drying the expandable polystyrene particles containing aluminum hydroxide, the blending agent was coated to evaluate the physical properties, and the results are shown in Table 1.

< Example 4 >

Using the same mini-pellet polystyrene particles as in <Example 2>, it was prepared in the same manner as in <Example 2> except that 0.5 parts by weight of toluene (SK) was introduced in the impregnation process. Next, after dewatering and drying the expandable polystyrene particles containing aluminum hydroxide, the blending agent was coated to evaluate the physical properties, and the results are shown in Table 1.

< Comparative Example 1 >

100% by weight of polystyrene (Kumho Petrochemical; HIPS 490FB) was melted in a twin screw forming machine at 200 ^o C, and extruded using a hot cutting pelletizer to have an average volume of 1.5 mm ³ Pellets of from 5 mm ³ were obtained. Next, 100 parts by weight of polystyrene particles in pellet form, 100 parts by weight of pure water, 0.24 parts by weight of a suspending agent (tricalcium phosphate, Dubon; DET-10), and a flame retardant (hexabromocyclododecane, GLC; CD75P ^TM ) 0.35 weight The part was inserted into the reactor at room temperature, the temperature was reacted at 70 ^° C. for 1 hour and 30 minutes, and after the completion of the temperature increase at 120 ^° C., 7% of a blowing agent (pentane, SK) was added and maintained for 5 hours. The foamed polystyrene particles thus obtained were dehydrated and dried, followed by coating a blending agent to evaluate physical properties. The results are shown in Table 1 below.

Property Example 1 Example 2 Example 3 Example 4 Comparative Example 1 5 minutes effervescent 40 40 40 50 40 Foam lip appearance Oval Oval Oval rectangle Oval Foam Density (kg / m ³ ) 0.030 0.030 0.030 0.030 0.030 Flame retardant (sec) 0.1 0.0 0.0 0.1 1.5 Bubble size (mm) 200-500 70-120 60-100 70-100 100-120 Absorption amount (g / 100cm ² ) 0.95 0.39 0.38 0.40 0.52

Evaluation of the physical properties expected in Table 1 was performed specifically as follows.

1) 5-minute foamability: foamed drainage (doubled) when foamed for 5 minutes at 0.3K steam pressure

2) Density: Mass (kg) / Volume of molded articles (m3)

3) Flame retardancy: measured by KSM-3808 method

4) Bubble size: average diameter between cell wall and cell (mm; measured under microscope)

5) Absorption amount: It is the number divided by the surface area of water absorbed according to the absorption method of expanded polystyrene insulation according to KS M 3808. (g / 100cm2)

From the results of Table 1, the introduction of aluminum hydroxide into the expandable polystyrene particles was confirmed that the effect of improving the flame retardancy, and the decrease in physical properties due to the increase in bubble size due to the introduction of aluminum hydroxide to control the appropriate bubble size by the addition of a bubble control agent Could.

In addition, the selection of a blowing agent having a high boiling point such as cyclopentane and excellent solubility in polystyrene in the introduction of a blowing agent positively improves the thermal conductivity, and the introduction of a solvent such as toluene and ethylbenzene increases the solubility of the blowing agent in polystyrene. It was confirmed that stabilization of the effervescent polystyrene particles over time, improved foamability, and spheronization of the polystyrene particles in the form of pellets.

Although the present invention has been described in detail in the above embodiments, the above embodiments are not described to limit the scope of the present invention, but are described for illustrative purposes only.

Those skilled in the art will recognize that modifications of the invention are possible without departing from the scope and spirit of the invention, and the scope of the invention is determined by the following claims.

The polystyrene produced by the present invention is excellent in flame retardancy and is suitable for use in various insulation materials including construction.

Claims (11)

Aqueous suspending the suspendable polystyrene pellets comprising aluminum hydroxide; And Heating by adding a blowing agent and a C6-C10 hydrocarbon; Method for producing expandable polystyrene particles having excellent flame retardant properties, including. The method of claim 1, wherein the polystyrene pellets have an L / D of 0.1.0 to 3.0 mm / 0.5-3.0 mm or a volume of 5 mm ³ or less. The method of claim 1 wherein the polystyrene particles are styrene, ethylstyrene, dimethylstyrene, para-methylstyrene, alpha-methylstyrene, alpha-ethylstyrene, alpha-propylstyrene, alpha-butylstyrene, chlorostyrene, bromostyrene and vinyl. A polymer or copolymer of a monomer of toluene, a copolymer of a monomer with acrylonitrile, butadiene, methyl acrylate, methyl methacrylate, isobutylene, vinyl chloride, isophorene and mixtures thereof. The method of claim 1 wherein said heating step comprises heating at a temperature of 100-130 ° C. for 3-12 hours. The method of claim 1, wherein the size of the aluminum hydroxide particles contained in the polystyrene pellets is characterized in that 0.1 ㎛ to 50 ㎛. The method according to claim 1 or 5, wherein the aluminum hydroxide particles are 5 to 70 parts by weight based on 100 parts by weight of polystyrene particles. The method of claim 1, wherein the pellet further comprises an infrared absorber selected from the group consisting of impression graphite, carbon black, magnesium hydroxide, glass fiber, carbon fiber, clay, loess. The method of claim 1, wherein the blowing agent is a cyclopentane alone or at least one selected from the group consisting of aliphatic hydrocarbons, halogenated hydrocarbons, halogen-free hydrocarbons except cyclopentane. 9. The method according to claim 1 or 8, wherein the blowing agent uses 1-15 parts by weight based on 100 parts by weight of polystyrene polymer. The method of claim 1, wherein the C6-C10 aromatic hydrocarbon is selected from the group consisting of toluene, ethylbenzene and mixtures thereof. The method of claim 1, wherein the aromatic hydrocarbon is used in an amount of 0.1 to 1 parts by weight based on the polystyrene polymer.