KR20000062119A - Expandable polystyrene resin and a method of producing the same - Google Patents

Abstract

PURPOSE: A method for preparing a polystyrene resin foam-molded body which and the polystyrene resin foam-molded body with high intensity prepared by foaming the polystrene resin with a low magnifying power are provided. CONSTITUTION: The method comprises steps of: (i) obtaining a pre-foamed bead by putting a foaming polystyrene resin in a foam container having a stirring device and then directly heating it with steam having a pressure of 0.1-0.5 kilogram/minute and a temperature of 180-230°C; (ii) drying the pre-foamed bead; (iii) filling up a pre-heated mold with the dried foamed bead; and (iv) heating the filled foamed bead with steam having a pressure of 0.5-2 kilogram/minute and a temperature of 180-230°C and exhausting air, cooling down and then releasing the foamed bead. The polystyrene resin foam molded body comprises an integrated bottom and side walls. In the bottom a pair of circular piercing holes are formed and inside edge portion, which is a boundary between the bottom and the side walls, is formed to bend at a regular center of curvature not to be transformed by internal stress and many reinforcing ribs are formed on the inside and outside of the side walls to reinforce the intensity.

Description

Expanded polystyrene resin and a method of producing the same

The present invention relates to the production of a polystyrene resin foamed molded article, and more particularly, to a high-strength polystyrene resin foamed molded article produced by foaming a polystyrene resin at low magnification and a method for producing the same.

In general, polystyrene resin is a polymer of styrene, a colorless transparent solid thermoplastic resin, has excellent water resistance, refractive index, transparency, high frequency insulation, and molded articles are used in electric parts, household goods, refrigerator parts, and the like. Such polystyrene resins have used foamed molded articles molded into foams in which an expandable polystyrene (EPS) raw material is placed in a foaming vessel and then foamed by indirectly heating the vessel.

However, this indirect heating manufacturing method has a disadvantage in that fuel consumption due to indirect heating is severe and a large-scale facility investment is required. In addition, since it is difficult to uniformly heat up to the inside and the temperature control is not easy, the molded article obtained by this method is often foamed at a high magnification of 5 times or more, so that there is a defect in density and weak strength.

In addition, the thickness of the molded body is not uniform throughout. For example, in the case of a box-shaped molded article, there is a problem that the thick portion of the edge is not adhered properly at the time of molding and the strength is weakened.

The present invention has been made to solve the conventional problems as described above, the first object of the present invention is to reduce the fuel consumption required for heating, do not require extensive facility investment, and easy to control the temperature of the foam of the correct magnification It is to provide a method for producing a polystyrene resin foam molded article that can be produced.

A second object of the present invention is to provide a high density polystyrene resin foam molded article having a high density.

1 is a view schematically showing a state in which a foam is located between the molds used in the present invention,

Figure 2 is a perspective view of a polystyrene resin foam molded article produced by the present invention,

3A is a plan view of the polystyrene resin foamed molded product shown in FIG. 2, and

3B is a bottom view of the polystyrene resin foam molded article shown in FIG. 2.

<Explanation of symbols for main parts of drawing>

11: fixed side mold 12: moving side mold

13, 14: steam passing gate 20: foam

30: transport box 32: bottom

34 side wall 36 through hole

38: inner edge portion 39: reinforcing rib

In order to achieve the first object described above, the present invention,

Placing the expandable polystyrene resin in a foaming vessel with a stirring device, and foaming by directly heating with a pressure of 0.1 to 0.5 kg / cm 3 and steam at a temperature of 180 to 230 ° C. (S1);

Transferring the pre-expanded beads to a drying furnace to dry (S2);

Filling the dried foam beads into a preheated mold (S3); And

Method for producing a polystyrene foamed molded article comprising the step (S4) of heating the filled foam beads with a pressure of 0.5 ~ 2kg / cm 3 and steam at a temperature of 180 ~ 230 ℃ to provide.

In addition, in order to achieve the above second object, the present invention,

The foamed polystyrene resin was placed in a foaming vessel and foamed by directly heating with a pressure of 0.1 to 0.5 kg / cm 3 and steam at a temperature of 180 to 230 ° C. to obtain a preliminary foamed beads, and drying the thus obtained preliminary foamed beads, followed by preliminary It is prepared by filling a heated mold with a pressure of 0.5 to 2 kg / cm 3 and steam at a temperature of 180 to 230 ° C., followed by exhausting, cooling and releasing, and including an integral bottom and sidewalls. A pair of circular through-holes for positioning is formed, and inner corners, which border the bottom and the sidewalls, are curved to have a constant curvature radius to prevent deformation during stress generation, and strength reinforcement is provided inside and outside the sidewalls. It provides a polystyrene foam molded article characterized in that a plurality of reinforcing ribs are formed for.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

In general, the foaming of the expandable polystyrene has been carried out by an indirect heating method of heating the outside of the foam container, in which case the foaming of the polystyrene is foamed at least 5 to 25 times even when using a low magnification foamable polystyrene raw material. Thus, a foamed molded article having a relatively low density and a weak strength is obtained.

High strength foams with low strength have no problems when used as fillers or disposable containers, but they are difficult to use for moldings that require repeated use several times and require durability, such as transport boxes for automatic transfer devices. .

In order to solve this problem, in the present invention, it is possible to obtain a foam of 2.5 to 3.5 times by measuring the density while appropriately adjusting the temperature by a direct heating method using steam.

At this time, the pressure of the steam injected is adjusted to 0.1 to 0.5 kg / cm 3, preferably 0.2 kg / cm 3, and the temperature is about 180 to 230 ° C. The temperature of the nozzle part for injecting steam is adjusted to 80 to 100 ° C, preferably 92 ° C, and the temperature inside the foam container is adjusted to 70 to 100 ° C, preferably 70 to 90 ° C, more preferably 80 ° C. do. At this time, if the temperature of the steam is too low, the foaming is not made well, if the temperature is too high, the foaming is made rapidly, it is difficult to control the expansion ratio.

When the foaming proceeds, if the density is measured at regular intervals and the foaming ratio is 2.5 to 3.5 times when the foaming is transferred to the drying furnace, no further foaming proceeds. That is, the foaming proceeds only under a constant vacuum pressure and steam heating atmosphere. At this time, the foaming and drying operations are carried out continuously.

The mold is preheated with steam and filled with foam beads. 1 is a view schematically showing a state in which a foam is located between the molds used in the present invention. As shown in FIG. 1, the mold used in the present invention is composed of a fixed side mold 11 and a moving side mold 12, and each mold 11, 12 is disposed between the molds 11, 12. It has steam passing gates 111, 112 arranged regularly to supply steam to the foam 20.

At this time, the thin part of the molded body is the same as the thickness of the mold and the depth of the steam passing gate 111 is divided into 3 to 5 sections, but the part to be molded thick thickness of the molded body as shown in the drawing By expanding the inlet so that the cross section of the inlet side to be supplied is V-shaped, forming the depth of the steam passage gate 112 shallowly, and forming it as one hole, the speed of steam is faster and the amount of steam is increased. And higher temperature steam was supplied. As a result, even adhesion or shaping | molding occurs even if the thickness of a molded object differs, and intensity | strength becomes uniform.

The filled pre-expanded beads are heated with a pressure of 0.5 to 2 kg / cm 3, preferably 1 kg / cm 3 and steam at a temperature of 180 to 230 ° C., from the fixed side mold 11 to the moving side mold 12. After heating for 4 minutes, it is evacuated to prevent segregation. After supplying steam from the moving side mold 12 to the fixed side mold 11 for 3 to 6 minutes, the both sides are heated and then exhausted, and the moving side mold 12 is heated to the fixed side mold 11 for 3 to 5 minutes. Heat by 3 steps of heating method of auxiliary heating. Next, the remaining steam is completely removed and cooled using a cooling water, and the vacuum is allowed to stand to cool, and then air is injected into the molds 11 and 12 for release.

Hereinafter, embodiments of the present invention will be briefly described.

<Example 1>

40 kg of low-foaming EPS (LEND-10 from Kumho Petrochemical) with a particle size of 0.6 to 0.9 mm is placed in a foam container with a hopper and a spiral rotary wing attached to the inner center at the top of a steam of 0.2 kg / cm 3 and a temperature of 200 ° C. Was supplied. The temperature of the nozzle part which sprays steam was adjusted to 92 degreeC, and the temperature inside foaming container was adjusted to 80 degreeC. The foam was weighed every 5 minutes with a measuring cup of 5,200 mm 3, and when it reached 2.8 magnification, it was transferred to a drying furnace and dried.

The mold was preheated with steam in advance and filled with foam beads. The filled foam beads are heated by steam having a pressure of 1 kg / cm 3 and a temperature of 200 ° C., which is heated for 220 seconds from the fixed mold to the movable mold and then evacuated, and is further heated from the movable mold to the fixed mold. Was performed for 180 seconds. Exhaust steam is completely removed by exhaust and cooled by using cooling water, and then vacuum is cooled by cooling. After that, air is first blown into the moving mold, the mold is opened, and then air is blown into the fixed mold to release the molded body. It was. The density of the molded product thus prepared was 0.357 g / cc.

<Example 2>

40 kg of low-foaming EPS (LEND-10 from Kumho Petrochemical) with a particle size of 0.6 to 0.9 mm is placed in a foam container with a hopper and a spiral rotary wing attached to the inner center at the top of a steam of 0.2 kg / cm 3 and a temperature of 200 ° C. Was supplied. The temperature of the nozzle part which sprays steam was adjusted to 92 degreeC, and the temperature inside foaming container was adjusted to 80 degreeC. The foam was weighed every 5 minutes by 5,200㏄ measuring cup, and when it reached 3.1 magnification, it was transferred to a drying furnace and dried.

The mold was preheated with steam in advance and filled with foam beads. The filled foam beads are heated with steam at a pressure of 1 kg / cm 3 and a temperature of 200 ° C., and after 300 seconds of heating from the fixed side mold to the moving side mold, the steam is also supplied from the moving side mold to the fixed side mold. After 350 seconds of double-sided heating and evacuation, auxiliary heating was performed for 250 seconds from the moving mold to the fixed mold. Next, exhaust steam is completely removed, and the remaining steam is cooled and cooled by cooling. The vacuum is then allowed to cool, and then the air is first blown to the moving mold, the mold is opened, and then the air is blown to the fixed mold to release the mold. A molded article was prepared. The density of the molded product thus prepared was 0.320 g / cc.

2 is a perspective view of a polystyrene resin foam molded article produced by the present invention, FIG. 3A is a plan view, and FIG. 3B is a bottom view.

As shown in Figs. 2 to 3B, the transport box 30 of the automatic transport apparatus, which is a polystyrene resin foam molded article manufactured by the present invention, includes an integral bottom 32 and side walls 34. The bottom 32 is provided with a pair of through holes 36 for positioning the transport box 30 in the automatic transfer line. The through hole 36 is formed in a circular shape to prevent deformation during stress generation. When the through holes 36 are formed in a rectangular shape, the stress is concentrated on the rectangular corners, and cracks easily occur. Therefore, the through holes 36 are preferably formed in a circular shape.

Inside the transport box 30, the inner edge portion 38, which is the boundary between the bottom 32 and the side wall 34, is formed to be curved with a constant radius of curvature R to prevent deformation during stress generation. When the inner edge portion 38 is formed to be curved, the stress applied to the inner edge portion 38 is dispersed toward the bottom 34 and the side wall 34 to effectively prevent the occurrence of cracks. On the inside and outside of the side wall 34, a plurality of reinforcing ribs 39 are formed for reinforcing strength.

The transport box 30 of the automatic transport device formed as described above has a smaller degree of deformation during stress generation than the conventional transport box, a small number of through holes for positioning the transport box, and a notch is formed in the center portion. Manufacturing cost is reduced.

As described above, according to the present invention, the fuel consumption required for heating is low, a large amount of facility investment is not required, and the temperature can be easily controlled to produce a foam having an accurate magnification. Moreover, the density of the whole molded object becomes the same, and a high density molded object with high density can be manufactured. The polystyrene foamed molded article produced by the present invention is particularly useful for molded articles requiring repeated use several times and requiring durability, such as, for example, a transport box of an automatic transfer device.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Claims (4)

Placing the expandable polystyrene resin in a foaming vessel with a stirring device, and foaming by directly heating with a pressure of 0.1 to 0.5 kg / cm 3 and steam at a temperature of 180 to 230 ° C. (S1); Transferring the pre-expanded beads to a drying furnace to dry (S2); Filling the dried foam beads into a preheated mold (S3); And A method of producing a polystyrene foamed molded article comprising the step (S4) of heating the filled foam beads with a pressure of 0.5 to 2 kg / cm 3 and steam at a temperature of 180 to 230 ° C. and then evacuating, cooling, and releasing. The method of manufacturing a polystyrene foam molded article according to claim 1, wherein in the step S4, when the filled foam beads are heated with the steam, the amount of the steam is changed in accordance with a desired thickness of the molded article. . 3. The mold of claim 2 wherein the mold is comprised of a stationary side mold and a moving side mold, wherein the stationary side mold and the moving side mold have steam passing gates arranged regularly to supply steam to the foam disposed therebetween. The depth of the steam passing gate corresponding to the thin part of the molded body is equal to the thickness of the mold, and the steam passing gate corresponding to the thick part of the molded body has a V-shaped cross section at the inlet side. Method for producing a polystyrene foam molded article characterized in that it is expanded to be. The foamed polystyrene resin was placed in a foaming vessel and foamed by directly heating with a pressure of 0.1 to 0.5 kg / cm 3 and steam at a temperature of 180 to 230 ° C. to obtain a preliminary foamed beads, and drying the thus obtained preliminary foamed beads, followed by preliminary It is prepared by filling a heated mold with a pressure of 0.5 to 2 kg / cm 3 and steam at a temperature of 180 to 230 ° C., followed by exhausting, cooling and releasing, and including an integral bottom and sidewalls. A pair of circular through-holes for positioning is formed, and inner corners, which border the bottom and the sidewalls, are curved to have a constant curvature radius to prevent deformation during stress generation, and strength reinforcement is provided inside and outside the sidewalls. Polystyrene foam molded article characterized in that a plurality of reinforcing ribs are formed for.