KR100902786B1 - Expandable Polystyrene Using Recycled Styrene Resin and Method of Preparing the Same - Google Patents

Abstract

The present invention is to prepare a mixed composition by mixing the carbon particles to the styrene resin containing the expanded polystyrene effluent waste material, blowing agent; Extruding the mixed composition; And impregnating the extruded mixed composition with a blowing agent at a temperature of 85 to 100 ° C., and to a method for producing expandable polystyrene using a regenerated styrene resin.

Expandable polystyrene resin, carbon particles, recycled polystyrene resin, internal moisture content, uniform cell structure, foamability, strength, heat insulation, environmental friendliness

Description

Expandable Polystyrene Using Recycled Styrene Resin and Method of Preparing the Same}

Field of invention

The present invention relates to an expandable polystyrene using a recycled styrene resin and a method for producing the same. More specifically, although the present invention contains a large amount of unusable fine grains and allelic resins containing a blowing agent generated during polystyrene-based resin immersion waste or expandable polystyrene suspension polymerization, the internal moisture content is low, uniform cells (Cell) The present invention relates to an expandable polystyrene having excellent structure, foaming property, strength, and heat insulating property, having physical properties equivalent to those of a polystyrene resin produced without using a recycled material, and capable of receiving environmentally friendly certification including a recycled material.

Background of the Invention

Generally, foamed molded articles of expandable polystyrene have high strength, light weight, buffering capacity, waterproofness, thermal insulation, and heat insulation, and are used as packaging materials for household appliances, agricultural product boxes, rich people, and home insulation materials. Among them, 70% of domestic demand is used as insulation for housing due to the light weight, insulation, and heat insulation of expanded polystyrene. In order to obtain the same heat insulating performance, the performance of the heat insulating material has the advantage that the outer wall can be slimmed down by reducing the thickness of the heat insulating material, thereby increasing the living space, and thus, there has been a demand for improving the heat insulating performance.

The foamed molded article is produced by heating the expandable polystyrene-based resin particles above the softening point by steam or the like to prepare pre-expanded particles having independent bubbles therein, and then heating them with a steam in a mold to mutually fuse them.

Heat transfer mechanisms of styrenic foams can generally be divided into solid phase conduction, gas phase conduction, radiation between bubble membranes, and convection of gases in the bubble. Among these, convection of gas in a bubble is normally ignored when the bubble diameter is 4 mm or less.

The lower the foaming ratio of the styrene resin foam, the lower the thermal conductivity and the better the thermal insulation performance.

This is because the ratio of the styrene resin decreases as the expansion ratio increases, so that the number of heat flow interruptions per unit thickness decreases, that is, the influence of the conduction of the solid phase decreases, so that the thermal conductivity increases. Therefore, the technique of controlling the size of the cell (Cell) to increase the number of heat flow blocking per unit thickness is important.

As another method for improving the thermal conductivity of styrenic foams, recently, a method of reducing the thermal conductivity by containing graphite in the expandable polystyrene has been developed.

US Patent No. 6,340,713 discloses a process for preparing expanded styrene-containing foamed styrene, comprising the steps of extruding, cooling, pulverizing, and particleting a mixture of graphite into polystyrene and then injecting a blowing agent.

In Korean Patent No. 70823, carbon particles are mixed with a first pellet containing styrene resin to prepare a mixed composition, extrude the mixed composition to prepare a second pellet, and inject a blowing agent into the second pellet. A method for producing expandable polystyrene by two steps is disclosed.

However, in the case of preparing a foamable polystyrene resin containing a large amount of styrene-based resin containing a damping waste material or a blowing agent, the foamed polystyrene resin is contaminated, low in weight average molecular weight, and a foaming agent as a plasticizer. And anti-blocking agent, so that the glass transition temperature (Tg) is lowered, causing difficulty in extrusion, lowering of dispersion efficiency of additives, cell non-uniformity of blowing agent, and particle formation phenomenon when blowing agent is used. Compared with the non-polystyrene resin, problems such as internal moisture content improvement, foaming property deterioration, strength deterioration, and thermal insulation performance deterioration occur.

In order to solve the above problems, the present inventors use carbon particles in a styrene-based resin (hereinafter referred to as waste styrene-based resin) containing a blowing agent such as expanded polystyrene-impregnated waste material and a foamable polystyrene (EPS) resin containing a blowing agent. Mixing to prepare a mixed composition, extruding the mixed composition, and impregnating the extruded mixed composition with a blowing agent at a temperature of 85 to 100 ° C., using a method for preparing expandable polystyrene, It is to develop eco-friendly foamable polystyrene without deterioration of foamability and insulation performance.

An object of the present invention is to provide an environment-friendly foamable polystyrene resin composition containing carbon particles excellent in heat insulating performance.

Another object of the present invention is an expandable polystyrene resin composition including a recycled material having a physical property equivalent to that of a polystyrene resin that does not use a recycled material, even though it contains a large amount of recycled styrene resin, and a polystyrene resin composition thereof and It is for providing a manufacturing method.

Yet another object of the present invention is to provide a method for producing expandable polystyrene having a uniform cell structure through a drying method using an eco-friendly resin, but without using a conventional cell control agent.

Another object of the present invention is to use an environmentally friendly recycled resin having a low glass transition temperature (Tg) by including a blowing agent and an antiblocking agent, so that the foaming polystyrene which can solve the deformation between pellets generated during the injection of the blowing agent is solved. It is to provide a manufacturing method.

The above and other objects of the present invention can be achieved by the present invention described in detail.

Summary of the Invention

Method for producing expandable polystyrene of the present invention is to prepare a mixed composition by mixing the carbon particles in the styrene resin containing a blowing agent; Extruding the mixed composition; And impregnating the extruded mixed composition with a blowing agent at a temperature of 85 to 100 ° C.

In another embodiment of the present invention, 3 to 10 parts by weight of the carbon particles are used based on 100 parts by weight of the styrene resin.

In another embodiment of the invention the blowing agent is used 3 to 8 parts by weight based on 100 parts by weight of the mixed composition.

The styrenic resin may include: expandable polystyrene (EPS) resin including a melting waste material or a blowing agent; Or general purpose polystyrene (GPPS), high impact polystyrene (HIPS) resin, acrylonitrile-butadiene-styrene copolymer (ABS), styrene-acrylonitrile copolymer (SAN), styrene-methyl methacrylate copolymer, poly Blends of methyl methacrylate or mixtures of two or more thereof with the expandable polystyrene (EPS) resins can be used.

Hereinafter, specific contents of the present invention will be described in detail below.

Detailed Description of the Invention

Conventionally, carbon particles such as graphite are added to general-purpose polystyrene (GPPS) and high-impact polystyrene (HIPS) resins, but the present invention provides a styrene-containing foaming agent such as expanded polystyrene-impregnated waste material and expanded polystyrene (EPS) resin including a blowing agent. Based on the resin (hereinafter referred to as waste styrene resin), carbon particles are mixed therein.

The expanded polystyrene effluent waste material is pelletized into a fused product of expanded polystyrene (EPS), which is used as a commercial packaging material.

The foamable polystyrene (EPS) resin including the blowing agent may be used as it is, the low-value commercial particles, fine particles of the resin produced in suspension polymerization of the expandable polystyrene. Conventionally, the particulate and opposing resin particles generated during the suspension polymerization process of the expandable polystyrene cannot be used as the expanded styrene product, and because it contains a blowing agent, it has been difficult to use for other purposes. In the present invention, by using the conventionally discarded fine particles and particles of resin particles as raw materials, it is environmentally friendly and economical efficiency can be improved.

The waste foamed styrene resins include expanded polystyrene-impregnated waste materials, foamed polystyrene (EPS) resins containing foaming agents, and general polystyrene (GPPS), high impact polystyrene (HIPS) resins, and acrylonitrile-butadiene-styrene copolymers. (ABS), a styrene-acrylonitrile copolymer (SAN), a copolymer of styrene-methyl methacrylate, polymethyl methacrylate or a mixture of two or more thereof may be used.

The waste-foamed styrene resin serving as the raw material of the present invention is preferably a weight average molecular weight of 130,000 to 300,000 g / mol.

In addition, as the styrene resin, if necessary, a flame retardant, a plasticizer, a pigment, and an antistatic agent may be added within a normal range.

The carbon particles contain 3 to 10 parts by weight based on 100 parts by weight of the waste styrene resin. The carbon particles may be graphite, carbon black or a mixture thereof, but are not limited thereto.

Carbon particles are mixed with the styrene resin containing the blowing agent to form a mixed composition.

In an embodiment of the present invention, the mixed composition may further include an additive selected from an antiblocking agent, a flame retardant, and a mixture thereof.

When the additive is included, in one embodiment of the present invention, the mixed composition is 84 to 95% by weight of the waste styrene resin, 0.001 to 3% by weight of antiblocking agent, 0.001 to 3% by weight of flame retardant and 3 to 10 carbon particles. It comprises by weight percent.

The anti-blocking agent may be used as ZINC STEARATE and HYDROXY CASTOR OIL as a material that can be selectively used so that the particles adhere to each other when foaming, or is easily fused when the insulation is manufactured, but is not limited thereto.

As the flame retardant, a halogen-based flame retardant such as hexabromocyclododecane and tribromophenyl allyl ether may be used, and hexabromocyclododecane may be preferably used.

The mixed composition is extruded and pelletized. Extruder used in the present invention is not particularly limited, but the extrusion temperature is preferably adjusted to 150 ~ 200 ℃.

The extruded mixed composition is impregnated with a blowing agent.

Conventionally, the blowing agent is injected at 100 to 135 ° C. higher than the glass transition temperature (Tg) of the pellet. In the present invention, the blowing agent is injected at 85 to 100 ° C. lower than the glass transition temperature of the pellet. In particular, when the blowing agent is injected, a small amount of initial blowing agent is gradually increased to increase the internal pressure of the reactor at a uniform speed, thereby preventing the formation of pellets. Injecting the blowing agent at a constant rate, which is a common method, causes a large amount of pellet deformation due to an initial rapid increase in the internal pressure of the reactor. In addition, it is possible to save energy since high temperature is not required above 100 ° C. Injecting a small amount of blowing agent into the mixed composition as described above and gradually adding the blowing agent to the reactor can be easily carried out by those skilled in the art.

The blowing agent input amount may be 3 to 8 parts by weight of the blowing agent based on 100 parts by weight of the extruded mixed composition.

The blowing agent is well known in the art to which the present invention pertains, but halogenated hydrocarbons such as butane, isobutane, n-pentane, isopentane, neopentane, hexane and the like may be used, but are not limited thereto. .

In one embodiment of the present invention, after the dispersion and the emulsifier is added to the extruded mixed composition, the temperature is raised to a temperature of 85 ~ 100 ℃ and then the blowing agent is added.

Magnesium pyrophosphate may be prepared by calculating and introducing stoichiometrically 0.1 to 2 parts by weight of sodium pyrophosphate, 10 hydrochloride Na 4 P 2 O 7, 10H 2 O and 0.1 to 2 parts by weight of magnesium chloride and hexahydrate in 100 parts by weight of ultrapure water. The emulsifier may be a conventional known emulsifier.

The expandable polystyrene in which the blowing agent is added is dehydrated and dried after maintaining 2 to 6 hours.

In the present invention, by using a polyethylene wax which is a commonly used cell control agent, by maintaining the drying conditions at a temperature of 40 ~ 50 ℃ for 2 to 5 hours in the drying process, a uniform cell structure according to ripening Can have

The expandable polystyrene prepared by the above method has a uniform cell structure and has a cell size of 0.01 to 0.05 mm. When the cell size has a uniform structure of 0.01 to 0.05 mm, expandable polystyrene excellent in foamability, strength, and thermal conductivity can be obtained.

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

Example 1

A mixed composition was prepared by mixing 5 parts by weight of graphite (TIMCAL S-249) having an average particle size of 6 parts with 100 parts by weight of regenerated GPPS pellets (EPS vulcanized products for home packaging) having a weight average molecular weight of 140,000 g / mol. It was extruded by an extruder and pelletized at 200 degreeC in the dimension of width x length 1.3 mm x 1.5 mm. Ultrapure water was prepared by stirring 0.8 parts by weight of sodium pyrophosphate (10 hydrate) Na 4 P 2 O 7 .10H 2 O and 0.9 parts by weight of magnesium chloride (hexahydrate) in 100 parts by weight of ultrapure water, and then 100 parts by weight of the extruded pellet and 0.1 parts by weight of calcium stearate. It injected | thrown-in and raised to the temperature range of 95 degreeC. 7.5 parts by weight of a pentane mixed gas was added thereto to maintain a constant rise in the reactor pressure, and then maintained for 5 hours. The expanded polystyrene particles containing graphite thus obtained were dehydrated and dried at 40 ° C. for 4 hours, coated with an antiblocking agent to prepare expanded polystyrene, and then the physical properties were evaluated and the results thereof were measured and shown in Table 1 below.

Example 2

50 µm by weight of regenerated GPPS pellets (EPS vulcanized products for home packaging) with a weight average molecular weight of 140,000 g / mol and 50 parts by weight of expanded styrene resin (OFF SIZE EPS) having a weight average molecular weight of 240,000 g / mol. A mixed composition was prepared by mixing 5 parts by weight of phosphorus graphite (TI-2 SAL Co., Ltd. S-249), extruded with a twin screw extruder, and pelletized at a temperature of 200 ° C. in a size of 1.3 mm × 1.5 mm. Ultrapure water was prepared by stirring 0.8 parts by weight of sodium pyrophosphate (10 hydrate) Na 4 P 2 O 7 .10H 2 O and 0.9 parts by weight of magnesium chloride (hexahydrate) in 100 parts by weight of ultrapure water, and then 100 parts by weight of the extruded pellet and 0.1 parts by weight of calcium stearate. It injected | thrown-in and raised to the temperature range of 95 degreeC. 7.5 parts by weight of a pentane mixed gas was added thereto so that the pressure inside the reactor was constantly raised, and then maintained at a temperature of 95 ° C. for 5 hours. The expanded polystyrene particles containing the graphite thus obtained were dehydrated and dried at 40 ° C. for 4 hours, coated with an antiblocking agent to prepare expanded polystyrene, and then the physical properties were evaluated to measure the results thereof.

Comparative Example 1

50 µm by weight of regenerated GPPS pellets (EPS vulcanized products for home packaging) with a weight average molecular weight of 140,000 g / mol and 50 parts by weight of expanded styrene resin (OFF SIZE EPS) having a weight average molecular weight of 240,000 g / mol. A mixed composition was prepared by mixing 5 parts by weight of phosphorus graphite (TI-2 SAL Co., Ltd. S-249), extruded with a twin screw extruder, and pelletized at a temperature of 200 ° C. in a size of 1.3 mm × 1.5 mm. Ultrapure water was prepared by stirring 0.8 parts by weight of sodium pyrophosphate (10 hydrate) Na 4 P 2 O 7 .10H 2 O and 0.9 parts by weight of magnesium chloride (hexahydrate) in 100 parts by weight of ultrapure water, and then 100 parts by weight of the extruded pellet and 0.1 parts by weight of calcium stearate. It injected | thrown-in and raised to the temperature range of 125 degreeC. 7.5 parts by weight of a pentane mixed gas was added thereto at a constant rate, and then maintained at a temperature of 125 ° C. for 5 hours. The expanded polystyrene particles containing graphite thus obtained were dehydrated and dried in vacuo, and then coated with an antiblocking agent to prepare expanded polystyrene, and then the physical properties were evaluated to measure the results thereof.

Comparative Example 2

A mixed composition was prepared by mixing 5 parts by weight of graphite (TIMCAL S-249) having an average particle size of 6 μm with 100 parts by weight of GPPS pellets (Cheil Industries GP HR-2390P00) having a weight average molecular weight of 270,000 g / mol. The plate was re-extruded with a twin screw extruder having a diameter of 1.5 mm and pelletized at a temperature of 200 ° C. in a size of 1.3 mm × 1.5 mm. To 100 parts by weight of ultrapure water was prepared by stirring 0.8 parts by weight of sodium pyrophosphate (10 hydrate) Na 4 P 2 O 7 .10H 2 O and 0.9 parts by weight of magnesium chloride, and then 100 parts by weight of the re-extruded pellet and 0.1 parts by weight of calcium stearate were added thereto. The temperature was raised to 125 ° C. 8 parts by weight of a pentane mixed gas was added thereto at a constant rate, and then maintained at a temperature of 125 ° C. for 5 hours. The expanded polystyrene particles containing graphite thus obtained were dehydrated and dried in vacuo, and then coated with an antiblocking agent to prepare expanded polystyrene, and then the physical properties were evaluated to measure the results thereof.

The physical properties of the foamed polystyrene prepared above were evaluated by the following method, and the evaluation results are shown in Table 1.

1) Weight average molecular weight (g / mol) was measured by Gel Permeation Chromatography.

2) Three minutes foamability (times): The magnification of foaming for 3 minutes at 0.3K steam pressure was measured.

3) Deformation (wt%): Deformation particles per 100g were selected and the weight was measured and expressed as wt%.

4) Foam density (kg / m ³ ): It is expressed as the mass of the molded article / the volume of the molded article.

5) Thermal conductivity (W / m · K): It was measured by the thermal conductivity measurement method of the thermal insulation material specified in KS L 9016.

6) Absorption rate (g / 100 cm ² ): was measured in accordance with the absorbance measurement method of the foamed polystyrene insulation stipulated in Korean Industrial Standard KS M 3808.

7) Cell size (mm): The average diameter of the cells was measured.

8) Compressive strength (kgf / cm ² ): It was measured according to the compressive strength measurement method of expanded polystyrene insulation according to Korean Industrial Standard KS M 3808.

TABLE 1

As shown in Table 1, the foamability, particle adhesion, thermal conductivity and the physical properties of the expandable polystyrene of Examples 1 and 2 prepared by the production method of the present invention is the expandable polystyrene resin of Comparative Example 2 using a general-purpose polystyrene resin (GPPS) It was found that the level is equivalent to. In addition, the expandable polystyrene of Comparative Example 1 using the same recycled polystyrene resin as used in Example 2 is prepared by drying the pellets impregnated above the glass transition temperature, unlike the expandable polystyrene of Example 2, the cell size is increased and the expansion ratio And it was confirmed that the thermal conductivity is lowered. It is understood that the expandable polystyrene of the present invention prepared in Examples 1 and 2 has a smaller weight average molecular weight than the expandable polystyrene of Comparative Example 2 prepared using a general-purpose polystyrene resin, but the compressive strength shows the same level as the expandable polystyrene of Comparative Example 2. Could.

The present invention is certified to be environmentally friendly, including recycled styrene resin, which has a low internal moisture content, a uniform cell structure, excellent foamability, strength and heat insulation, and physical properties equivalent to those of a polystyrene resin that does not use recycled materials. It has the effect of providing the expandable polystyrene resin composition and its manufacturing method which can be received.

Claims (10)

Preparing a mixed composition by mixing carbon particles with waste styrene resin; Extruding the mixed composition; And Impregnating the extruded mixed composition with a blowing agent at a temperature of 85 to 100 ° C .; Method for producing expandable polystyrene using a recycled styrene resin, characterized in that consisting of steps. According to claim 1, The waste foamed styrene-based resin is expanded polystyrene immersion waste material, foamed polystyrene (EPS) resin containing a blowing agent; Or general purpose polystyrene (GPPS), high impact polystyrene (HIPS) resin, acrylonitrile-butadiene-styrene copolymer (ABS), styrene-acrylonitrile copolymer (SAN), copolymer of styrene-methylmethacrylate, poly A method for producing expandable polystyrene, which is a blend of methyl methacrylate or a mixture of two or more thereof and the expandable polystyrene (EPS) resin. The method of claim 1, wherein the waste foamed styrene resin has a weight average molecular weight of 130,000 to 300,000 g / mol. The method of claim 1, wherein the carbon particles are graphite, carbon black or a mixture thereof. The method of claim 1, wherein the carbon particles are used in an amount of 3 to 10 parts by weight based on 100 parts by weight of the waste foamed styrene resin. The method of claim 1, wherein the mixed composition further comprises an antiblocking agent, a flame retardant or a combination thereof. The method of claim 6, wherein the mixed composition comprises 84 to 95% by weight of waste foamed styrene resin, 0.001 to 3% by weight of antiblocking agent, 0.001 to 3% by weight of flame retardant and 3 to 10% by weight of carbon particles. Method for producing expandable polystyrene. The method of claim 1, wherein the dispersing agent and the emulsifier are added to the extruded mixed composition, and then heated to a temperature of 85 to 100 ° C. and then impregnated with a blowing agent. The method of claim 8, wherein the blowing agent is used 3 to 8 parts by weight based on 100 parts by weight of the mixed composition. delete