KR101992628B1 - The fabrication method of expanded polystyrene particle and expanded polystyrene particle - Google Patents

Abstract

The method for producing expanded polystyrene particles comprises the steps of: preparing an organic phase of polystyrene by dissolving a styrene monomer, a styrene-based resin, an expanded graphite, and a bulk polymerization initiator in a reactor; bulk- Preparing a mixture of an aqueous phase by mixing an ionized water, a dispersant, and a surfactant; providing a suspension polymerization initiator and a mixture of the aqueous phases to the reactor to conduct polish-styrene particles; And providing a foaming agent to the reactor to produce expanded polystyrene particles.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing expanded polystyrene particles and a method for producing the expanded polystyrene particles,

TECHNICAL FIELD The present invention relates to a method for producing expanded polystyrene particles and foamed polystyrene particles, and more particularly to a method for producing expanded polystyrene particles having a high content of an inorganic substance in a core of expanded polystyrene particles and foamed polystyrene particles.

In recent years, inorganic materials have been introduced to improve various physical properties of foamed polystyrene foam. Generally, in order to improve the heat insulation performance, graphite, carbon black, metal oxides, metal powders and the like are introduced. In order to improve the flame retardant performance, , Metal hydroxides, nonmetal hydroxides, phosphorus flame retardants, bromine flame retardants, melamine flame retardants, and boron-based flame retardants.

Techniques for introducing an inorganic material into a foamed polystyrene particle include a method of coating an inorganic material with a foamed polystyrene particle or a foamed lip or an adhesive with a glue, a method of introducing an inorganic substance into a polystyrene extruder, Or a method of impregnating a foaming agent during extrusion, and a method of introducing an inorganic material into suspension polymerization to produce conventional foamed polystyrene particles.

In general, the introduction of an inorganic material in the suspension polymerization is disadvantageous in that it can not introduce a large amount of inorganic materials because there is a part in which foamed polystyrene is difficult to be granulated due to problems such as dispersion instability and polymerization rate decline during polymerization, , Some inorganic particles are desorbed and scattered into the air due to the expansion of the expanded polystyrene particles in the subsequent process such as molding, and the environment and the human body are adversely affected, and the final remaining inorganic content with respect to the input amount is low.

Foams made from expanded polystyrene-based particles are widely used as building materials because of their excellent heat insulation performance and easy workability, but they are disadvantageous in that their flame retardancy is inferior to inorganic insulation materials such as glass fiber and gypsum board. Foamed polystyrene particles are mainly used as general building insulation materials or sandwich panels. In recent years, it has been limited in use due to frequent fire and danger of buildings designed with sandwich panels. To apply foamed polystyrene foam, flame retardant materials Flame retardancy is required.

In introducing a flame retardant additive to improve the flame retardant performance of foamed polystyrene foam, a method of coating a flame-retardant composition on foamed polystyrene particles or foamed lips or molded articles, a flame retardant additive in a suspension polymerization process for producing expanded polystyrene particles Is known.

Korean Patent Publication No. 2011-0017794 discloses a method for producing a flame retardant composition having excellent fuming inhibiting properties by using a metal hydroxide such as aluminum hydroxide, a non-metal hydroxide and an expanded graphite, a hardener, and a liquid vinyl acetate resin adhesive, A method for preparing expanded polystyrene particles having a flame retardant composition coated thereon is disclosed. When the surface of the foamed polystyrene particles is physically coated with a flame retardant, the flame retardant is easily detached from the foaming and molding processes, which are post-processes for producing the foam, and the flame retardancy of the final product does not greatly improve the flame retardant content. Further, in addition to the conventional method of producing a polystyrene foam, a flame retardant composition requires a process such as coating, drying, and the like. Thus, the workability is lowered and the uniform physical properties of the foam are deteriorated. This has the disadvantage of being disturbed.

Korean Patent Laid-Open No. 2001-0071028 discloses another method for producing expanded polystyrene particles containing graphite particles by polymerizing styrene in an aqueous suspension in the presence of expanded graphite. In the method for producing expanded polystyrene particles by the suspension polymerization method, when the expanded graphite is over 20 parts by weight in order to improve the flame retardancy, the expanded polystyrene particles can not be caught by dispersion instability, As the expanded polystyrene particles expand in the same subsequent process, the expanded graphite particles are desorbed and scattered into the air, which adversely affects the environment and human body. It is difficult to secure the flame retardant performance due to the low residual expansion graphite content relative to the input amount.

Korean Patent Publication No. 2011-0017794 Korean Patent Publication No. 2001-0071028

It is an object of the present invention to provide a method for producing expanded polystyrene particles capable of improving the content of inorganic substances introduced during polymerization and improving the desorption of inorganic substances in post-processing such as foaming or molding, without additional processes other than the conventional foaming and molding processes .

It is an object of the present invention to provide a method for producing foamed polystyrene particles having an excellent flame retardancy as well as self-extinguishing properties and a low heat release rate in the case of fire.

An object of the present invention is to provide a method for producing foamed polystyrene particles free from environmental pollution and harmful influence of human body due to scattering of powder due to desorption of inorganic substances during foaming and molding of expanded polystyrene particles.

An object of the present invention is to provide a foamed polystyrene particle capable of improving the content of inorganic substances introduced during polymerization and improving the desorption of inorganic substances in post-processes such as foaming or molding, without additional processes other than the conventional foaming and molding processes .

It is an object of the present invention to provide foamed polystyrene particles having excellent flame retardancy as well as self-extinguishing properties and a low heat release rate in the case of fire.

An object of the present invention is to provide foamed polystyrene particles free from environmental pollution and harmful influence of human body due to powder scattering due to desorption of inorganic substances during foaming and molding of expanded polystyrene particles.

The method for producing expanded polystyrene particles according to an embodiment of the present invention includes the steps of preparing an organic phase of polystyrene by dissolving a styrene monomer, a styrene-based resin, an expanded graphite, and a bulk polymerization initiator in a reactor, A step of bulk polymerization, a step of mixing a de-ionized water, a dispersant, and a surfactant to prepare an aqueous phase mixture, a step in which a suspension polymerization initiator and a mixture of said aqueous phases are provided, Preparing styrene particles, and providing a foaming agent to the reactor to produce foamed polystyrene particles.

The bulk polymerization may be carried out at 70 to 92 占 폚 for 1 to 2 hours.

The step of preparing the polystyrene particles may be performed for 3 to 6 hours.

The step of preparing the expanded polystyrene particles may be performed by heating the reactor at a temperature of 100 to 130 ° C for 1 to 4 hours.

The step of preparing the expanded polystyrene particles may further include a step of cooling the heated reactor.

The step of preparing the organic phase polystyrene may further comprise providing at least one of a flame retardant and a bubble regulator.

The step of preparing the polystyrene particles may further be to provide a pH adjusting agent.

In the step of preparing the organic-phase polystyrene, the styrene-based resin may be a polystyrene resin.

In the step of preparing the organic phase-modified polystyrene, the expanded graphite may have a particle size of 20 to 1,000 μm.

In the step of producing polystyrene of the organic phase, the expanded graphite may be contained in an amount of 5 to 50 parts by weight based on 100 parts by weight of the expanded polystyrene particles.

In the step of producing the organic phase polystyrene, the bulk polymerization initiator may be benzoyl peroxide.

In the step of preparing the aqueous phase mixture, the suspension polymerization initiator may include at least one of t-butyl peroxy-2-ethylhexanoate and t-butyl peroxybenzoate.

In preparing the aqueous phase mixture, the dispersant may be sodium pyrophosphate, and magnesium sulfate.

In preparing the aqueous phase mixture, the surfactant may comprise at least one of sodium lauryl sulphonate, sodium sulphate alkyl sulphonate, and sodium sulphoole sulphonate.

In the step of producing the expanded polystyrene particles, the foaming agent is at least one of butane, i-butane, n-pentane, i-pentane, neo- pentane, cyclopentane, and halogenated hydrocarbons having 4 to 6 carbon atoms .

A foamed polystyrene particle according to an embodiment of the present invention includes a core containing an inorganic substance and a shell surrounding the core and containing no inorganic substance.

According to the method for producing expanded polystyrene particles according to an embodiment of the present invention, it is possible to improve the content of inorganic substances introduced during polymerization without additional steps other than the conventional foaming and molding processes and to remove inorganic substances from the post- It is possible to produce foamed polystyrene particles which can be improved.

According to the method for producing expanded polystyrene particles according to an embodiment of the present invention, it is possible to produce foamed polystyrene particles having excellent flame retardancy, as well as self-extinguishing properties and low heat release rate in the case of fire.

According to the method for producing expanded polystyrene particles according to an embodiment of the present invention, environmental pollution due to scattering of powder due to desorption of inorganic substances during foaming and molding of the expanded polystyrene particles and harmful effects of the human body can be eliminated.

According to the expanded polystyrene particles according to an embodiment of the present invention, it is possible to improve the content of inorganic substances introduced during polymerization and to improve the desorption of inorganic substances in post-processes such as foaming or molding, .

According to the expanded polystyrene particles according to an embodiment of the present invention, not only self-extinguishing properties but also excellent flame retardancy performance with low heat release rate in the case of fire can be obtained.

According to the foamed polystyrene particles according to an embodiment of the present invention, environmental pollution due to powder scattering due to desorption of inorganic substances during foaming and molding of foamed polystyrene particles, and harmful effects of the human body can be eliminated.

1 is a flowchart schematically showing a method for producing expanded polystyrene particles according to an embodiment of the present invention.
2 is a cross-sectional view schematically showing expanded polystyrene particles according to an embodiment of the present invention.
Fig. 3 is a foamed lip formed by the expanded polystyrene particles of Example 1. Fig.
Fig. 4 is a foamed lip made of expanded polystyrene particles of Comparative Example 1. Fig.
Fig. 5 is a molded article formed from expanded polystyrene particles of Example 1. Fig.
Fig. 6 is a molded article formed from expanded polystyrene particles of Comparative Example 1. Fig.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features, and advantages of the present invention will become more readily apparent from the following description of preferred embodiments with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art.

Like reference numerals are used for like elements in describing each drawing. In the accompanying drawings, the dimensions of the structures are shown enlarged from the actual for the sake of clarity of the present invention. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The singular expressions include plural expressions unless the context clearly dictates otherwise.

In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, where a portion such as a layer, film, region, plate, or the like is referred to as being "on" another portion, this includes not only the case where it is "directly on" another portion, but also the case where there is another portion in between. On the contrary, when a part such as a layer, film, region, plate or the like is referred to as being "under" another part, it includes not only the case where it is "directly underneath" another part but also another part in the middle.

Unless otherwise specified, all numbers, values, and / or representations that express the amounts of components, reaction conditions, polymer compositions, and combinations used herein are intended to include those numbers It should be understood that in all cases the term "about" is to be construed as an approximation reflecting the various uncertainties of the measurement. Also, where a numerical range is disclosed in this specification, such a range is contiguous and includes all values from the minimum value of this range to the maximum value including the maximum value, unless otherwise indicated. Further, when such a range refers to an integer, all integers including the minimum value to the maximum value including the maximum value are included unless otherwise indicated.

In the present specification, when a range is described for a variable, it will be understood that the variable includes all values within the stated range including the end points described in the range. For example, a range of "5 to 10" may include any subrange, such as 6 to 10, 7 to 10, 6 to 9, 7 to 9, etc., as well as values of 5, 6, 7, 8, 9, And will also be understood to include any value between integers that are reasonable within the scope of the stated ranges such as 5.5, 6.5, 7.5, 5.5 to 8.5 and 6.5 to 9, and so on. Also, for example, a range of "10% to 30%" may range from 10% to 15%, 12% to 12%, as well as all integers including values of 10%, 11%, 12%, 13% And any arbitrary integer within the range of ranges described, such as 10.5%, 15.5%, 25.5%, and the like, including any subranges such as 18%, 20%

Hereinafter, a method for producing expanded polystyrene particles and expanded polystyrene particles according to an embodiment of the present invention will be described.

1 is a flowchart schematically showing expanded polystyrene particles according to an embodiment of the present invention.

Referring to FIG. 1, a method for producing expanded polystyrene particles according to an embodiment of the present invention includes the steps of: dissolving a styrene monomer, a styrene resin, an expanded graphite, and a bulk polymerization initiator in a reactor to prepare an organic phase of polystyrene S100), bulk polymerizing the polystyrene of the organic phase (S200), de-ionized water, a dispersant, and a surfactant to prepare an aqueous phase mixture (S300) (S400) of producing polystyrene particles by proceeding with slow polymerization, and providing a blowing agent to the reactor to produce expanded polystyrene particles (S500).

The styrene monomer, styrene resin, expanded graphite, and bulk polymerization initiator are dissolved in the reactor to prepare polystyrene of organic phase (S100). The step (S100) of preparing the organic phase polystyrene may be performed until the styrene-based resin is completely dissolved.

The styrene monomer may be at least one of styrene, alkylstyrene, alpha-alkylstyrene, halogenated styrene, and vinyltoluene, as long as it is ordinarily used.

The alkylstyrene is not particularly limited as long as it is ordinarily used, and may be, for example, ethylstyrene, dimethylstyrene, or para-methylstyrene.

The alpha-alkylstyrene can be, for example, alpha-methylstyrene, alpha-ethylstyrene, alpha-propylstyrene, or alpha-butylstyrene, as long as it is ordinarily used.

The halogenated styrene is not particularly limited as long as it is ordinarily used, but may be, for example, chlorostyrene or bromostyrene.

The styrenic resin may be, for example, a copolymer of a polymer or copolymer of a styrene monomer, a copolymer of a styrene monomer and a monomer copolymerizable with a styrene monomer, a styrene monomer and a mixture of a styrene monomer and a copolymerizable monomer.

The monomer copolymerizable with the styrene monomer may be, for example, acrylonitrile, butadiene, alkyl acrylate, alkyl methacrylate, isobutylene, vinyl chloride, or isoprene.

The alkyl acrylate is not particularly limited as long as it is ordinarily used, and may be, for example, methyl acrylate.

The alkylmethacrylate is not particularly limited as long as it is ordinarily used, and may be, for example, methyl methacrylate.

In the step (S100) of producing the organic-phase polystyrene, the styrene-based resin may be a polystyrene resin.

The styrene resin may be used in an amount of 5 to 60 parts by weight based on 100 parts by weight of the expanded polystyrene particles. When the amount of the styrene-based resin is less than 5 parts by weight, the viscosity of the organic phase is low, and the dispersion of the expanded graphite is poor, and when the aqueous phase is added and granulated, the polymerization rate is low. If the amount of the styrene resin is more than 60 parts by weight, the viscosity of the organic phase may be high, so that it may be difficult to granulate the dispersion due to dispersion instability when the aqueous phase is added and granulated.

Expanded graphite improves flame retardancy of expanded polystyrene particles. In the present invention, " inorganic " means expanded graphite. In the step (S100) of producing the organic phase polystyrene, the particle size of the expanded graphite may be 20 to 1,000 mu m. If the particle size of the expanded graphite is less than 20 탆, the flame retardant performance may be deteriorated. If the particle size of the expanded graphite is more than 1,000 탆, dispersion during polymerization may be unstable and it may be difficult to form expanded polystyrene particles.

In the step (S100) of producing the organic phase polystyrene, the expanded graphite may be contained in an amount of 5 to 50 parts by weight based on 100 parts by weight of the expanded polystyrene particles. If the content of expanded graphite is less than 5 parts by weight, the flame retardant performance may be deteriorated. If the content of expanded graphite is more than 50 parts by weight, characteristics inherent to polystyrene may be deteriorated, and foamed polystyrene particles It can be difficult.

The bulk polymerization initiator is not particularly limited as long as it is a conventional polymerization initiator used in the production of expandable polystyrene particles. For example, in step S100 of producing an organic phase polystyrene, the bulk polymerization initiator may be benzoyl peroxide. The content of the bulk polymerization initiator may be 0.1 to 1.0 parts by weight based on 100 parts by weight of the styrene-based monomer. If the content of the bulk polymerization initiator is less than 0.1 parts by weight, the bulk polymerization rate may be slow and the polymerization time may be long. If the content is more than 1.0 part by weight, the efficiency of initiating bulk polymerization may deteriorate compared with the content of the bulk polymerization initiator.

The step (SlOO) of producing the organic phase polystyrene may further be to provide at least one of a flame retardant and a foam modifier.

The flame retardant is not particularly limited as long as it is ordinarily used, and examples thereof include metal hydroxide such as aluminum hydroxide and magnesium hydroxide, phosphorus flame retardant such as red phosphorus, ammonium polyphosphate, diphenyl phosphate and triphenyl phosphate, , And decabromodiphenylethane; melamine-based flame retardants such as melamine, melamine cyanurate and melamine phosphate; and boron-based flame retardants such as zinc borate.

The content of the flame retardant may be 0.05 to 20 parts by weight based on 100 parts by weight of the expanded polystyrene particles. If the content of the flame retardant is less than 0.05 parts by weight, the flame retardancy may deteriorate. If the content is more than 20 parts by weight, the content of the styrene monomer, the styrene resin, and the expanded graphite may be small and the production efficiency of the expanded polystyrene particles may be decreased.

When the foamed polystyrene particles are foamed and molded to prepare a foamed product, the foam stabilizer can make the foamed cells of the foamed foam small and uniform so as to improve the fusion and mechanical strength of the molded product. The foam controlling agent is not particularly limited as long as it is usually used, and at least one of talc, polyethylene wax, ethylene bisstearamide, calcium carbonate, talc, clay, silica, diatomaceous earth, citric acid, and sodium bicarbonate can be used have. The content of the foam controlling agent may be 0.05 to 5 parts by weight based on 100 parts by weight of the expanded polystyrene particles. If the content of the bubble controlling agent is less than 0.05 part by weight, it is difficult to control the bubbles of the foamed lip small and uniformly, and if it exceeds 5 parts by weight, the bubble controlling efficiency may be lowered.

The organic phase polystyrene is subjected to bulk polymerization (S200). The bulk polymerization step (S200) may be carried out at 70 to 92 占 폚 for 1 to 2 hours. The step of bulk polymerization (S200) may be performed by heating the reactor to 70 to 92 占 폚 and maintaining the temperature for 1 to 2 hours. If the amount is less than the above range, the organic phase polystyrene may not be sufficiently bulk-polymerized, and if it exceeds the above range, defects may be generated in the organic phase polystyrene.

The bulk polymerization step (S200) may be performed, for example, until polymerization conversion of the organic phase polystyrene is 20 to 50%. When the polymerization conversion degree of the organic phase polystyrene is 20% or less, the viscosity is too low. If the polymerization conversion rate is more than 50%, the viscosity is too high, so that the dispersing agent should be used in large amounts due to dispersion instability during particle formation due to suspension polymerization, There may be a problem.

De-ionized water, a dispersant, and a surfactant are mixed to prepare an aqueous phase mixture (S300). In step S300 of preparing the aqueous phase mixture, the dispersing agent may comprise, for example, sodium pyrophosphate, and magnesium sulfate. The dispersant may be prepared, for example, by dissolving sodium pyrophosphate and magnesium sulfate in ultrapure water. For example, 0.1 to 5.0 parts by weight of sodium pyrophosphate and 0.1 to 7.0 parts by weight of magnesium sulfate may be used as a dispersant in 100 parts by weight of ultrapure water. If the amount is less than the above range, it may be difficult to inject the aqueous phase into the organic phase to granulate the polystyrene particles. If the amount is less than the above range, the efficiency of producing the polystyrene particles may be deteriorated.

In step S300 of producing an aqueous phase mixture, the surfactant may comprise at least one of sodium laurylsulfonate, sodium alkylbenzenesulfonate, and sodium oleoylsulfonate.

The content of the surfactant may be 0.05 to 1.0 part by weight based on 100 parts by weight of ultrapure water. If the content of the surfactant is less than 0.05, it may be difficult to granulate the polystyrene particles by introducing the aqueous phase into the organic phase, and if it exceeds 1.0 part by weight, the polystyrene particles may be made smaller than the preferred particle size.

In the reactor in which the bulk polymerization has proceeded, a suspension polymerization initiator and a mixture of aqueous phases are provided, and suspension polymerization is carried out to prepare polystyrene particles (S400). The polystyrene particles may be spherical.

      In the step (S400) of producing polystyrene particles, the suspension polymerization initiator may include at least one of t-butylperoxy-2-ethylhexanoate and t-butylperoxybenzoate. t-Butyl peroxy-2-ethylhexanoate is a low-temperature slow polymerization initiator. The low temperature may mean " 80 to 100 DEG C ". t-Butyl peroxybenzoate is a high-temperature suds polymerization initiator. The high temperature may mean " 110 to 140 캜 ". When t-butylperoxy-2-ethylhexanoate and t-butylperoxybenzoate are used at the same time, it is possible to proceed the suspension polymerization over a wide temperature range.

For example, the suds polymerization initiator may include 0.05 to 2.0 parts by weight of t-butylperoxy-2-ethylhexanoate and 0.05 to 0.5 parts by weight of t-butylperoxybenzoate based on 100 parts by weight of the styrene monomer. Lt; / RTI > If the amount is less than the above range, the slow polymerization may not proceed sufficiently, and if it is in the above range, the slow polymerization initiation efficiency may be lower than the sucro polymerization initiator content.

The step (S400) of producing the polystyrene particles may be to further provide a pH adjusting agent. The pH adjusting agent may include at least one of, for example, sodium hydrogencarbonate, ammonium carbonate, sodium hydroxide, ammonium hydroxide, dimethylamino ethanol, and calcium carbonate. The content of the pH adjusting agent may be 0.05 to 0.3 parts by weight based on 100 parts by weight of the expanded polystyrene particles. If the content of the pH adjusting agent is less than 0.05 part by weight, the pH of the foamed polystyrene particles may be low, which may result in an unstable dispersion and may not be granulated. When the amount of the pH adjusting agent is more than 0.3 parts by weight, The shape of the particles becomes long, and when the polymerization RPM is high, the particles can be subdivided and made smaller than the preferred particle size.

A foaming agent is provided in the reactor to produce expanded polystyrene particles (S500). The blowing agent may be, for example, provided to the reactor under nitrogen pressure. For example, after the foaming agent is added, the reactor may be closed to maintain the final pressure at 10 kgf / cm ² to produce expanded polystyrene particles (S500).

In step S500 of producing the expanded polystyrene particles, the foaming agent may be at least one selected from the group consisting of butane, i-butane, n-pentane, i-pentane, neo-pentane, cyclopentane, and halogenated hydrocarbons having 4 to 6 carbon atoms One may be included. The content of the blowing agent may be 4 to 15 parts by weight based on 100 parts by weight of the expanded polystyrene particles. When the content of the blowing agent is less than 4 parts by weight, the polystyrene particles can not be sufficiently foamed. When the amount is more than 15 parts by weight, the polystyrene particles excessively foam, or the foam size of the foam lips increases, Can fall.

The step S500 of producing expanded polystyrene particles may be performed by raising the temperature of the reactor to 100 to 130 ° C for 2 to 5 hours. In the reactor heated in the above range, the step (S500) of producing expanded polystyrene particles at a temperature of 100 to 130 ° C for 1 to 4 hours may be performed.

Step S500 of producing the expanded polystyrene particles may further include cooling the heated reactor. In the step of cooling the temperature-raised reactor, the temperature-raised reactor may be cooled to a temperature below the boiling point of the foaming agent. There is a variation in the concentration of the foaming agent in the expanded polystyrene particles upon discharge at a temperature higher than the boiling point, and there may be a problem that foamed lip bubbles are not uniform or large when foaming the expanded polystyrene particles.

The foamed polystyrene particles thus produced may be used by foaming or molding. For example, foamed polystyrene particles can be used as foamed lips, molded articles, or the like.

2 is a cross-sectional view schematically showing expanded polystyrene particles according to an embodiment of the present invention.

Referring to FIG. 2, expanded polystyrene particles 10 according to an embodiment of the present invention includes a core 100 and a shell 200. The core 100 comprises an inorganic material 110. The shell (200) surrounds the core (100). Shell 200 does not contain minerals.

The method for producing expanded polystyrene particles according to an embodiment of the present invention introduces an inorganic substance only in the core of the expanded polystyrene by introducing a bulk-slow polymerization process, thereby increasing the content of inorganic substances introduced into the expanded polystyrene particles, Or detachment of the inorganic substance from the expanded polystyrene particles during post-processing such as molding can be improved. In the present invention, the " center portion " may mean a portion spaced from the surface of the expanded polystyrene particles inside the expanded polystyrene particles.

In addition, the method for producing expanded polystyrene particles according to an embodiment of the present invention can provide expanded polystyrene particles having improved flame retardancy including expanded graphite.

Hereinafter, the present invention will be described more specifically by way of specific examples. The following examples are provided to aid understanding of the present invention, and the scope of the present invention is not limited thereto.

Example 1: 20 parts by weight of expanded graphite was introduced into the core through bulk-slow polymerization

740 g of polystyrene (GP 125E), 740 g of expanded graphite (LS-Chem; CX-150), 740 g of polystyrene (ethylene bis stearamide; available from LG Life Science Co., Ltd.) as a styrene monomer (SK) 29.6 g of a flame retardant (hexabromocyclododecane; Alvar) and 44.4 g of a flame-retardant auxiliary (dicumyl peroxide; Myungjin Ind.) Were dissolved at 380 RPM to prepare an organic phase. After the polystyrene of the organic phase was completely dissolved, 15.8 g of a bulk polymerization initiator (benzoyl peroxide; Hansol Chemical Co., purity: 75%) was charged into the reactor. The temperature of the reactor was raised to 91.5 캜, .

140 g of sodium pyrophosphate (Youngjin) and 250 g of magnesium sulfate (7 hydrates of Samseon Pure Chemical Industries, Ltd.) were dissolved in 2 kg of ultrapure water, and 20 g of a surfactant (alkylbenzenesulfonate; .

When polymerization conversion of polystyrene was about 30% in the bulk polymerization, 14.8 g of a low-temperature initiator (t-butylperoxy-2-ethylhexanoate; Century Akeema) as a suds polymerization initiator and 14.8 g of a high-temperature initiator (Calcium carbonate) (Dongho calcium), and the aqueous phase thus prepared were added to the mixture to obtain spherical particles, and the mixture was stirred for 5 hours while being subjected to slow polymerization . Thereafter the foaming agent to close the reactor inlet (n- pentane; Deoksan Pharmaceutical Co., Ltd.) added to a 370g into the reactor with nitrogen pressure, and maintaining the final reactor pressure was 10kgf / cm ² for 2 hours, temperature was raised and the reactor temperature was 125 ℃ and Thereafter, the foaming agent was impregnated while keeping the temperature constant for 2 hours. The reactor temperature was then cooled to 30 DEG C, and the foamed polystyrene resin particles were discharged from the reactor. The foamed polystyrene resin particles were washed with water, dried, foamed and molded, and the physical properties were evaluated.

Example 2: 25 parts by weight of expanded graphite was introduced into the core through bulk-slow polymerization

Expanded polystyrene resin particles were prepared in the same manner as in Example 1, except that 925 g of expanded graphite (LS-Chem; CX-150) was used in the step of producing the organic-phase polystyrene.

Comparative Example 1: Introduction of 20 parts by weight of expanded graphite as a general suspension polymerization

1.1 kg of polystyrene (GP 125E), 740 g of expanded graphite (LS-Chem; CX-150), 740 g of a foam controlling agent (ethylene bis stearamide; 29.5 g of a flame retardant (hexabromocyclododecane; Alba Mar), 44.4 g of a flame-retardant auxiliary (dicumyl peroxide; Myungjin Industry), 18.5 g of a low-temperature initiator (t-butylperoxy-2-ethylhexanoate; 13.0 g of a high-temperature initiator (t-butyl peroxybenzoate, Hosung Chemex) was dissolved at 380 RPM to prepare an organic phase of polystyrene. 140 g of sodium pyrophosphate (Youngjin) and 250 g of magnesium sulfate (7 hydrates of Samseon Pure Chemical Industries, Ltd.) were dissolved in 2 kg of ultrapure water, and 20 g of a surfactant (alkylbenzenesulfonate; . When the polystyrene resin of the polystyrene of the organic phase in the reactor was completely dissolved, spherical particles were prepared by charging 4.83 kg of ultrapure water, 6 g of a pH adjusting agent (calcium carbonate; Dongho calcium), and the prepared aqueous phase. The temperature of the reactor was raised to 91.5 ° C and polymerization was continued for 6 hours. Thereafter, the inlet of the reactor was closed, and 370 g of a foaming agent (n-pentane; Duksan Chemical Industry Co., Ltd.) was introduced into the reactor at a nitrogen pressure. While the final reactor pressure was maintained at 10 kgf / cm ² , After that, the foaming agent was impregnated while keeping the temperature constant for 2 hours. The reactor temperature was then cooled to 30 DEG C, and the foamed polystyrene resin particles were discharged from the reactor. The foamed polystyrene resin particles were washed with water, dried, foamed and molded, and the physical properties were evaluated.

Comparative Example 2: 25 parts by weight of expanded graphite was introduced as a general suspension polymerization

Expanded polystyrene resin particles were produced in the same manner as in Comparative Example 1, except that 925 g of expanded graphite (LS-Chem; CX-150) was used in the step of producing polystyrene of organic phase.

The physical properties of Example 1, Example 2, Comparative Example 1 and Comparative Example 2 were measured and reported in the following Table 1. The method for evaluation is as follows.

(1) Foam lip aeration: After foaming, 5 g of foaming lip was placed between 30 mesh sheaves and fired at a constant air pressure through the air gun.

(2) Foam Lip Expansion Graphite Content (%): A predetermined amount (W1) of the foamed lips before and after the foaming lip aeration was dissolved in tetrahydrofuran (THF) and then filtered through a glass microfire filter (GF / Respectively. The amount of expanded graphite remaining on the filter (W4 = W3-W2) was measured after drying the filter paper (W3) at 60 占 폚 to calculate the content. (W4 / W1 * 100)

(3) Total heat release rate (MJ / m ² ): A sandwich panel was made by attaching an iron plate to a molded product, and the flame retardancy test was conducted according to KS F ISO 5660-1, The total heat released was measured. In order to satisfy the flame retardant material (flame retardant grade 3), it should be less than 8 MJ / m ² .

(4) Time (sec) in which the heat release rate continuously exceeded 200 kW / m ² (second): A sandwich panel was made by attaching an iron plate to a molded product to perform a flame retardancy test according to KS F ISO 5660-1 And the time at which the heat release rate continuously exceeded 200 kW / m ² upon heating for 5 minutes was measured. In order to satisfy the flame retardant material (flame retardant grade 3), it must be 10 seconds or less.

(5) Observations: A sandwich panel with an iron plate attached to a molded product was subjected to a flame retardant test according to KS F ISO 5660-1, a flame retardant performance test method of a building finishing material, Harmful cracks, holes and melting were confirmed. To satisfy the flame retardant material (flame retardant grade 3), there should be no cracks, holes, melting.

Item Example 1 Example 2 Comparative Example 1 Comparative Example 2 Polymerization process Bulk-SUS Bulk-SUS Suse Suse The content of dissolved polystyrene (parts by weight) 20 20 30 30 Expanded graphite content (parts by weight) 20 25 20 25 Whether it is granulated Particle formation Particle formation Particle formation Particle formation
no Foaming lip
Expanded graphite content (%) Before Aeration (%) 16.62 19.98 15.17 - After Aeration (%) 16.60 19.95 12.68 After aeration
Removal amount of expanded graphite (%) 0.02 0.03 2.49 Cone calorimeter Heat release rate
(MJ / m 2) 3.0 2.7 4.1 Heat release rate of 200kW / ㎡
Consecutively exceeded time (s) 0 0 0 Observations
Hazardous cracks, holes and melting More than
none More than
none More than
none

From the results shown in the above Table 1, it can be seen that, in the case of the expanded polystyrene particles into which the inorganic substance is introduced into the core through the bulk-slow process, the expanded graphite content is increased from 20 parts by weight to 25 parts by weight and granulated without changing the content of dissolved polystyrene I can confirm that I can. On the contrary, when 20 parts by weight of expanded graphite is introduced into the suspension polymerization, 30 parts by weight or more of the polystyrene resin must be dissolved, and when expanded graphite is increased to 25 parts by weight, even if 30 parts by weight of the polystyrene resin is dissolved, . As shown in Fig. 4, expanded polystyrene particles polymerized by ordinary slow polymerization have many expanded graphite particles having a large particle size on the surface of the expanded polystyrene particles, and a part of the expanded graphite, which is physically embedded in the surface of the expanded polystyrene, It is detached and comes out. However, in the case of the expanded polystyrene particles polymerized by the bulk-slow polymerization, expanded graphite was introduced only in the center portion of the expanded polystyrene particles as shown in Fig. 3, and it was confirmed that the amount of expanded graphite desorption after foaming lip aeration was almost zero. 5 and 6, it can be seen that the molded article of Example 1 has a higher content of inorganic matter than that of the molded article of Comparative Example 1. [

In the flame retardant performance, it was confirmed that foamed polystyrene foam having expanded graphite existing only in the core in the bulk-suspend process is superior. By allowing the inorganic substance to exist in the core through the bulk-slow polymerization process, it is possible to introduce a larger amount of the inorganic substance than in the case of the general suspension polymerization, and even if the same amount of the inorganic substance is introduced, there is no inorganic desorption during foaming or molding, Was found to be better.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood. It is therefore to be understood that the above-described embodiments are illustrative and non-restrictive in every respect.

10: foamed polystyrene particles
100: Core
110: Minerals
200: Shell

Claims (16)

Dissolving a styrene monomer, a styrene-based resin, an expanded graphite, and a bulk polymerization initiator in a reactor to prepare an organic-phase polystyrene;
Bulk polymerization of the organic phase polystyrene;
Preparing a mixture of aqueous phases by mixing de-ionized water, a dispersant, and a surfactant;
Providing the reactor with a suds polymerization initiator and a mixture of the aqueous phases to progress the suspension polymerization to produce polystyrene particles; And
And providing a foaming agent to the reactor to produce expanded polystyrene particles,
Wherein the step of preparing the polystyrene particles further provides a pH adjusting agent. The method according to claim 1,
The bulk polymerization step
At 70 to 92 占 폚 for 1 to 2 hours. The method according to claim 1,
The step of preparing the polystyrene particles
Is carried out for 3 to 6 hours. The method according to claim 1,
The step of preparing the expanded polystyrene particles
Wherein the reactor is heated to perform the reaction at a temperature of 100 to 130 캜 for 1 to 4 hours. 5. The method of claim 4,
The step of preparing the expanded polystyrene particles
And cooling the heated reactor. ≪ Desc / Clms Page number 19 > The method according to claim 1,
The step of preparing the organic phase polystyrene
A flame retardant, and a foam modifier. ≪ RTI ID = 0.0 > 21. < / RTI > delete The method according to claim 1,
In the step of preparing the organic phase polystyrene,
Wherein the styrene-based resin is a polystyrene resin. The method according to claim 1,
In the step of preparing the organic phase polystyrene,
Wherein the expanded graphite has a particle size of 20 to 1,000 占 퐉. The method according to claim 1,
In the step of preparing the organic phase polystyrene,
Wherein the expanded graphite is contained in an amount of 5 to 50 parts by weight based on 100 parts by weight of the expanded polystyrene particles. The method according to claim 1,
In the step of preparing the organic phase polystyrene,
Wherein the bulk polymerization initiator is benzoyl peroxide. The method according to claim 1,
In the step of preparing the aqueous phase mixture,
Wherein said suspension polymerization initiator comprises at least one of t-butyl peroxy-2-ethylhexanoate and t-butyl peroxybenzoate. The method according to claim 1,
In the step of preparing the aqueous phase mixture,
Wherein the dispersing agent comprises sodium pyrophosphate, and magnesium sulfate. The method according to claim 1,
In the step of preparing the aqueous phase mixture,
Wherein the surfactant comprises at least one of sodium lauryl sulfonate, sodium alkyl benzene sulfonate, and sodium oleoyl sulfonate. The method according to claim 1,
In the step of producing the expanded polystyrene particles,
Wherein the blowing agent comprises at least one of butane, i-butane, n-pentane, i-pentane, neo-pentane, cyclopentane and halogenated hydrocarbons having 4 to 6 carbon atoms. delete

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