JPH0160407B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a continuous manufacturing method for polystyrene foam molded products. More specifically, it has a thin wall, can maintain a small stack height, and has practical strength.
In addition, the present invention relates to an economical method for continuously manufacturing polystyrene foam molded products. Conventionally, a method using an extruder has been known as one of the methods for manufacturing polystyrene foam molded products. In this method, a polystyrene resin composition is extruded and foamed from an extruder together with a foaming agent to form a sheet, which is wound onto a roll and left to mature for usually 2 to 3 weeks. In this method, the material is heated to a temperature of 100% and then supplied to a mold for molding. That is, in this method, the extrusion step and the molding step are completely independent, and it is necessary to carry out aging for a long time in between, which is disadvantageous in continuous production and also problematic in terms of economy. For example, if the above-mentioned aging is not carried out, problems such as changes in dimensions over time and poor moldability into molded products will occur. In order to solve these problems, a method has been proposed in which a thermoplastic resin foam molded product is continuously produced by feeding an extruded sheet into a rotary vacuum mold (see Japanese Patent Publication No. 37134/1983). However, with this method, the heat during extrusion is used directly to form the product, so the strength of the resulting molded product is weak due to insufficient stretching, deep drawing is not possible, and temperature control is extremely difficult. Therefore, there were problems such as it was difficult to balance the extrusion speed of the sheet and the molding speed, and if there was a problem in the molding process during continuous operation, it was necessary to stop the extruder operation, resulting in the suspension of the entire process. Furthermore, there was also a drawback that wide sheets could not be used, which caused problems in terms of production efficiency and resulted in a high loss rate. Therefore, a continuous manufacturing method that solves the above problems has been desired. On the other hand, foamed polystyrene resin molded products such as trays and partition underlays used for retail food products such as vegetables, fruits, meat, and salads usually have an expansion ratio of 10 or more, a wall thickness of 2 mm or more, and are durable. However, the disadvantages were that the stack height (the height of 100 stacked trays) was large and the molding cycle (the time from feeding the sheets to the molding die until the end of molding) was long. Of course, there are non-foamed polystyrene resin trays, and in that case, the wall thickness is about 0.3 mm and the stack height is small, but the molding cycle is long and the amount of resin used is large, so it ends up being uneconomical. Become. Therefore, there has been a desire for a polystyrene foam molded product that is thin, has a short molding cycle, and is economical. This invention was made to solve the above-mentioned problems, and provides a continuous manufacturing method that allows thin, economical polystyrene foam molded products to be continuously and easily obtained with sufficient strength in a short molding cycle. The purpose is to The inventors of this invention discovered that by using a polystyrene foam sheet extruded from an extruder and having a specific amount of residual gas of a blowing agent, thin and excellent molded products can be produced without substantially undergoing conventional aging. We discovered the fact that this can be obtained and arrived at this invention. Thus, according to the present invention, a polystyrene resin composition containing a rubber component as a blend or copolymerization component of 0 to 20% by weight based on the polystyrene resin and a foaming agent are extruded through a die of an extruder. Cooling the foam while uniaxially or biaxially stretching,
Bulk density 0.15-0.7g/ ^cm3 , thickness 0.3-1.0mm, number of bubbles in the thickness direction 5-20, residual gas amount of blowing agent 0.03-
A polystyrene foam molded product is obtained by forming a polystyrene foam sheet with a draw ratio of 0.3 mol/Kg and a draw ratio of 1.25 or less, and then heating and molding the foam sheet into an arbitrary shape without subjecting it to substantial aging. A method for continuously producing a polystyrene foam molded article is provided. Furthermore, from another point of view, a composite sheet is obtained by laminating a thermoplastic resin film on at least one side of the above-mentioned polystyrene foam sheet, and then this is similarly heated to form a polystyrene foam molded product into an arbitrary shape. A continuous manufacturing method is provided. The polystyrene resin used in this invention refers to a polymer whose main constituent unit is a styrene vinyl monomer such as styrene, methylstyrene, dimethylstyrene, etc., and other vinyl monomers such as acrylic acid, methacrylic acid, or these. It may also be a copolymer with ester, acrylonitrile, acrylamide, methacrylnitrile, maleic anhydride, or the like. Among these, polystyrene is preferred. Usually these polymers have a molecular weight of
Weight average molecular weight by GPC method: 5×10 ⁴ to 70
A material of about 10 ⁴ is suitable, but there is no particular limitation as long as it is commonly used or can be used as an extrusion molding material. As the above-mentioned polystyrene resin, usually available polymers in the form of powders, granules, pellets, etc., or compounds mainly composed of the same (meaning resins containing a small amount of lubricants, stabilizers, etc.) are used. is simple. Usually, when using these commercially available products, the melt index is approximately 1.2 to 25 (JIS
- K6870 measurement method) is suitable. In the polystyrene resin composition of the present invention, the rubber component is contained as a blend or copolymer component in an amount of 0 to 20% by weight based on the polystyrene resin. Various rubber components can be used, but when used as a blend component, butadiene rubber, ethylene-propylene rubber, styrene-propylene rubber, etc.
It is appropriate to use it by adding butadiene rubber, polyethylene, etc. to the polystyrene resin, and when using it as a copolymerization component, monomers or oligomers such as butadiene, isoprene, chloroprene, etc. are copolymerized at a predetermined molar ratio. It is appropriate to use a polystyrene resin (in this case, it will be understood that if a copolymer is used as the polystyrene resin, it will be in a terpolymer state including the rubber component. ). This rubber component is useful for imparting flexibility when used as a polystyrene foam sheet. Although it is possible to obtain the molded product of the present invention without including any rubber component at all, it is usually better to include even a small amount. Thus, the rubber component is preferably contained in an amount of 0.3 to 15%, more preferably 0.3 to 5.0%, based on the polystyrene resin. The polystyrene resin composition used in this invention may contain additives such as colorants, flame retardants, lubricants (hydrocarbons, fatty acids, , fatty acid amide-based, ester-based, alcohol-based, metal soap, silicone oil, waxes such as low-molecular polyethylene), spreading agents (liquid paraffin,
Polyethylene glycol, polybutene, etc.), dispersants, etc. may be added. Of course, some of these additives may be added during the production of the polystyrene resin. As the blowing agent, various volatile blowing agents and decomposable blowing agents can be used. Volatile blowing agents include hydrocarbons with boiling points of about -40°C to 45°C, such as propane, butane, and pentane, and boiling points of about -47°C to about -47°C, such as trichloromonofluoromethane, dichlorodifluoromethane, and 1,2-dichlorotetrafluoroethane. Halogenated hydrocarbons and mixtures thereof at 45°C are suitable. Examples of decomposable blowing agents include azodicarbonamide, dinitrosopentamethylenetetramine, 4,
An organic blowing agent such as 4'-oxybis(benzenesulfonyl hydrazide) or a combination of an organic acid or its salt such as sodium bicarbonate or citric acid with bicarbonate (however, each of these may be combined with a coating agent such as liquid paraffin). (may be coated) etc. are suitable. Depending on the case, carbon dioxide, nitrogen gas, water, etc. can also be applied. The amount of the foaming agent added varies depending on the type, but the amount used is such that the residual gas amount of the foaming agent in the foamed sheet is in the range of 0.03 to 0.3 mol/Kg. For example, the volatile blowing agent is used in an amount of about 0.03 to 0.4 mol/Kg based on the polystyrene resin. (This addition is usually carried out in an extruder.) Also, the decomposable blowing agent has a gas generation rate of 3 to 30 c.c./100 mg of blowing agent per 100 parts by weight of the polystyrene resin.
Parts by weight are used. Further, it is preferable to add a cutting agent to the polystyrene resin composition to help adjust the "number of bubbles in the thickness direction" of the polystyrene foam sheet of the present invention. Specific examples of engraving agents include talc, sodium hydrogen carbonate, ammonium hydrogen carbonate, calcium carbonate, clay, and citric acid, and small amounts of the aforementioned heat-dispersible foaming agents can also be used. The amount added to obtain the desired number of bubbles depends on the combination with the blowing agent. For example, when the cutting agent is talc and the blowing agent is butane or dichlorodifluoromethane, the amount of talc added is about 0.05 to 5.0% by weight, preferably about 0.3 to 2.0%, based on the polystyrene resin. In the combination of talc and pentane, about 0.05 to 5.0% by weight of talc, preferably about 0.5 to 2.5% by weight of the resin.
It is. In addition, when talc and a decomposable blowing agent are combined, the amount of talc added to the resin is approximately 0.01 to 3.5% by weight.
For example, when sodium bicarbonate and citric acid are used as the blowing agent, the foaming agent is approximately 0.05 to 1.5.
It is preferred to add talc in an amount of 0.04 to 2.0% by weight if an organic decomposition blowing agent such as azodicarbonamide is used. As the extruder in this invention, any known extruder can be used. As long as the die has a slit thickness of 0.15 to 0.6 mm, its shape may be flat, T-shaped, cylindrical, or the like. A polystyrene resin composition is fed into this extruder through a hopper. Additionally, the additives mentioned above are supplied as appropriate. When using a volatile foaming agent as the foaming agent, it is preferable to supply the foaming agent to an extruder separately from the polystyrene resin composition and mix therein. In the extruder, at least the polystyrene resin composition is melted by heating. At the same time, various additives added as necessary and the polystyrene resin composition are kneaded. The polystyrene foam extruded from the die of the extruder is uniaxially or biaxially stretched and cooled to form a sheet. Note that when using a cylindrical die (biaxial stretching is performed), the cylindrical extrudate is cut open to form a sheet. The stretching ratio is 1.25 for both uniaxial and biaxial stretching.
The following is necessary from the viewpoint of formability when the sheet is subjected to so-called sheet forming (heating and forming into an arbitrary shape). Before sheet forming, the surface temperature of the foam extruded from a die and made into a sheet must be cooled to at least the softening point temperature of the polystyrene resin, and is usually preferably 60°C or lower, more preferably 20°C or lower. ~50℃. This cooling is normally carried out by the atmosphere immediately after extrusion from the die, but in some cases cooling may be accelerated by bringing a cooling plug (suitable for biaxial stretching) or a cooling wall into contact. Normally, the time required for preheating (above the softening point of the sheet) from the die during sheet forming is 30 seconds to several minutes, depending on the amount of resin discharged when cutting and extruding using a circular die. Further, it is preferable that the distance from the die to the preheating section is approximately 8 to 15 meters. The distance and time from the die to the heating section can vary depending on various factors such as sheet thickness and take-up speed. However, as long as the polystyrene foam sheet is stabilized (the above-mentioned cooling), it is usually preferable to set the time and distance as short as possible in relation to the molding time (molding cycle). It will be appreciated that the times described above are longer than conventional aging. In the method of the present invention, the term "without aging" or "without substantially aging" does not include the conventional long period of time, e.g. 1 to 2 weeks, but includes at least several minutes and, in some cases, In some cases, this may be within a few hours. The term "several hours" includes, for example, when a sheet is manufactured, the process is stopped midway, and the sheet is formed the next day. Even in such a case, the final molded product is not substantially affected by leaving the sheet alone. In this invention, the amount of residual gas in the sheet obtained by extrusion foaming is controlled to 0.03 to 0.3 mol/Kg. The amount of residual gas can be roughly controlled by adjusting the amount of blowing agent described above, but if the sheet obtained by extrusion foaming slightly exceeds the residual gas amount range described above, the take-up distance may be lengthened to remove the gas. The amount of residual gas may be controlled by providing some venting time or by providing a zone in which the foamed sheet being taken up is heated at 40 to 50° C. to vent gas. Normally, immediately after extrusion of a polystyrene foam sheet, the foaming agent begins to dissipate from within the cells to the outside air, and air begins to flow into the cells. When the residual gas amount exceeds 0.3 mol/Kg as in the case of conventional sheets, the blowing agent tends to dissipate and the pressure inside the cells is reduced, which takes time to replace the blowing agent and air. This is necessary from the viewpoint of subsequent moldability. However, as in the present invention, if it is 0.3 mol/Kg or less, the amount of blowing agent in the cells is stable, and even if air flows into the cells, the amount of blowing agent escaping is very small. Therefore, the pressure inside the bubbles is not reduced, and subsequent moldability is good, and it is believed that heat molding can be performed immediately after extrusion. The adjustment of the amount of residual gas in the sheet as described above can be said to be one of the major findings that made it possible to continuously manufacture molded products without providing substantial aging time. In this invention, the foamed polystyrene sheet obtained by the above steps has a low foaming ratio of 1.5 to 7.0. In other words, the bulk density is 0.15 to 0.7 g/
equivalent to ^m2 . If this is less than 1.5, the amount of resin required will increase, and the amount of heat required during hot molding will also increase, resulting in a longer molding cycle. On the other hand, if the foaming value is higher than 7.0, the strength will be weakened, making it impossible to produce thin-walled molded products. The foaming ratio is mainly controlled by the amount of foaming agent added. In addition, the thickness of the polystyrene foam sheet is approximately 0.3 to 1.7 cm by vacuum forming or press forming.
Since we are obtaining a molded product with a diameter of
It can be easily controlled by extruding and withdrawing at an appropriate speed through a die having a diameter of 0.15 to 0.6 mm. The "number of bubbles in the thickness direction" of a polystyrene foam sheet is 5 to 20. The term "number of cell membranes in the thickness direction" as used herein means the number of cell membranes lined up in the thickness direction, excluding the skin layers at both ends, in a cross section of the sheet taken in the thickness direction.
If it is less than 5, the cell structure in the thickness direction will be insufficient and the strength will be poor. Conversely, if the number of bubbles is too large, the bubbles become too thin and flexible. As mentioned above, the number of foamed membranes is controlled mainly by the amount of nucleating agent added. The polystyrene foam sheet thus obtained can be immediately molded without being left for aging. That is, a desired thin-walled polystyrene foam molded product can be obtained by heating the sheet to a temperature above its softening point, supplying it to a mold, molding it, and appropriately cutting and trimming it. In this invention, the polystyrene foam molded product may have its surface covered with an unfoamed thermoplastic resin film, and in particular, a polystyrene resin composition with little or no rubber content is used. In this case, the covering film increases its mechanical strength, which is preferable. Additionally, a covering film may be required for sealing purposes. Therefore, according to another aspect of the present invention, a polystyrene resin composition containing a rubber component as a blend or copolymer component of 0 to 20% by weight based on the polystyrene resin and a blowing agent are further added to an extruder. (a) A laminated foam obtained by laminating thermoplastic resin film layers in a die and extruded from a die while being uniaxially or biaxially stretched, or (b) A foam obtained by extruding from a die. By uniaxially or biaxially stretching and cooling and laminating thermoplastic resin film layers, a bulk density of 0.15 to 0.7 g/cm ³ ,
Thickness 0.3~1.0mm, number of bubbles in the thickness direction 5~20,
A composite sheet is obtained by laminating a thermoplastic resin film on at least one side of a foamed polystyrene sheet with a residual gas amount of 0.03 to 0.3 mol/Kg and a stretching ratio of 1.25 or less, and then the composite sheet is substantially not subjected to aging. Provided is a method for continuous production of a polystyrene foam molded product, characterized in that the polystyrene foam molded product is obtained by heating and molding into an arbitrary shape. Examples of the resin for the thermoplastic resin film include resins that can generally be made into sheets, such as polystyrene, polyethylene, impact-resistant polystyrene that is a mixture or copolymer of polystyrene and rubber, polypropylene, and polyethylene terephthalate. Polystyrene, high-density polyethylene, and high-impact polystyrene are preferred in terms of moldability, and polystyrene and high-impact polystyrene are more preferred in terms of ease of use. Note that these films may be stretched to some extent. When laminating a thermoplastic resin film on a polystyrene foam sheet within a die, a merging die (for example, a crosshead die) may be used, or the lamination may be performed by flowing in before the die slit. In addition, when laminating polystyrene foam sheets after extrusion and foaming, it is also possible to combine a thermoplastic resin film extruder with a take-off machine to extrude the films and laminate them continuously. This may be carried out by appropriately laminating a thermoplastic resin film on a polystyrene foam sheet. Note that the above-mentioned lamination may be performed by using an adhesive or by heat fusion. The thickness of the thermoplastic resin film is appropriately set to a level that does not interfere with molding, and although it varies depending on the type of resin, it is usually preferably about 5 to 300 μm. By subjecting the composite sheet to heat molding in the same manner as described above, a desired thin-walled polystyrene foam molded product can be obtained. Hereinafter, a specific example of the continuous manufacturing method of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing a specific example of an apparatus used in the continuous production method of polystyrene foam molded products of the present invention. In Figure 1, for example, the rubber component is
A polystyrene resin composition (granular) containing about 10% as a blend component is supplied from a hopper 1, heated in an extruder 2, and then transferred to a blowing agent supply control device 3.
a and a volatile foaming agent supplied through the foaming agent supply pipe 3 to form a slit with a thickness of 0.15~
The foam is extruded into a cylindrical shape using a 0.6 mm cylindrical die 4 at a die temperature of about 110° C., and stretched in both axial directions. The cylindrical foam 5 obtained by extrusion foaming is cooled to below the softening point temperature by the atmosphere and a cooling plug 6, and is continuously cut open with a cutter knife 7 to form a sheet, which is then cut into a sheet by a take-up roll 8a and a step. It is continuously taken off by a take-off device 8 equipped with rolls 8b. This sheet-like foam is then supplied to the molding section, where it is further cooled to near room temperature by passing through a take-off device 8, and has a bulk density of 0.15 to 0.7.
g/cm ³ , thickness 0.3-1.0mm, number of bubbles in the thickness direction: 5
~20, residual gas amount 0.03~0.3 mol/Kg, stretching ratio 1.25
The polystyrene foam sheet 9 is controlled to have the following physical properties. The polystyrene foam sheet 9 is fed by a chain 11 to a preheating section 10 equipped with heaters 10a above and below, where it is heated above its softening point, and then fed to a press molding section 12 equipped with a large number of desired molding dies 12a. and then subjected to sheet forming. The aggregate 15 of the molded polystyrene foam molded products is cut with a cutter 13 for each molding cycle, and after being moved by the conveyor 14, each molded product is removed and trimmed as appropriate to form the desired polystyrene foam molded product. is obtained. Incidentally, since the above-mentioned molding cycle is performed intermittently, the sheet supply is regulated by the step roll 8b. Furthermore, if this press forming section 12 is replaced with a rotary system, it is possible to perform continuous press forming without adjustment using the stepped rolls 8b. In addition, even if trouble occurs in the press forming section, the step roll 8b and the preheating section 1
The foamed sheet can be rolled up and kept as appropriate between the two, and there is no need to stop the operation of the extruder. On the other hand, as shown in FIG. 2, by connecting the adhesive extruder 19 and the thermoplastic resin extruder 17 with a crosshead die, a thermoplastic resin film is die-cast into the melt of the polystyrene resin composition. By repeating the process as described above, the polystyrene foam molded article of the present invention having a laminated film can be continuously obtained. In the continuous manufacturing method of the present invention as described above, the preheating time for sheet forming is about 1 to 14 seconds,
Compared to about 4 to about 10 seconds for conventional expanded polystyrene sheets and about 10 to about 15 seconds for non-expanded polystyrene sheets, it is the widest and most flexible and has the shortest minimum time, resulting in the shortest molding cycle. sell. The present invention will be explained in more detail below with reference to Examples. This will make the various advantages of this invention clearer. Example 1 A molded article was manufactured using an apparatus similar to that shown in FIG. Polystyrene was added to an extruder with a screw diameter of 90 mmφ.
95 parts by weight (Styron 691, manufactured by Asahi Dow Co., Ltd.) 5 parts by weight of polystyrene containing 10% by weight of butadiene rubber (Denka Styrol, HIU-1, manufactured by Denki Kagaku Kogyo Co., Ltd.)
), 1.2 parts by weight of talc, and 0.1 parts by weight of liquid paraffin were uniformly mixed in a tumbler and fed through a hopper, heated to about 200°C, and mixed with butane as a blowing agent at a ratio of 0.27 mol/Kg of the mixture. The mixture was press-fitted and melted and kneaded. This molten mixture is passed through a cylindrical die (slit interval 0.35 mm) installed at the tip of the extruder at a die temperature of 110°C and a discharge rate of 85°C.
Extrusion foaming was carried out at Kg~90Kg/hr. The obtained cylindrical foam was then cooled to about 82°C through a cooling plug, stretched 1.15 times in the longitudinal direction and 1.2 times in the width direction, cut out the cylindrical shape with a cutter to form a sheet, and rolled into a stepped roll (20 mmφ). ×2 and 30mmφ roller) and take-up roll (320mmφ
During this time, the surface temperature of the sheet decreased to about 40°C. Subsequently, the sheet was fed by a chain into a preheating chamber equipped with an infrared heater heated to about 430°C, and the sheet was heated to 110°C or higher.
It is fed into a press mold for trays (4 x 9), and sheets are formed under the conditions of a 6.4-second cycle and a press pressure of 1.5 tons, and each forming unit is cut with a cutter. A tray as shown was obtained. The physical properties of the expanded polystyrene sheet before sheet molding are: bulk density 0.61 g/cm ³ , thickness 0.8 mm, number of bubbles in the thickness direction 12, residual gas amount approximately 0.2 mol/Kg, stretching ratio length 1.15, width 1.2, The basis weight was 120 g/m ² . Further, the specifications of the tray (with ribs) obtained from the above sheet are shown in Table 1 together with the conventional tray (with ribs).

[Table] The detailed specifications of the tray according to the present invention other than those mentioned above are as follows. () Material: Expanded polystyrene rubber content: 0.5% Expansion ratio: 6.1 times () Shape: See Figures 3 to 8 () Dimensions: (i) Length: 195 mm, Width 103 mm Height: 19 mm Peripheral side wall Inclination angle: α = 75 degrees β = 75 degrees (ii) Rib (10): Height (a ₅ ) 3 mm Groove width (b ₅ ) 1 mm, Groove depth (c ₅ ) 0.5 mm (iii) Rib (18) : height (a ₆ ) 1 mm, groove width (b ₆ ) 3 mm, groove depth (c ₆ ) 0.5 mm or more. This is comparable to molded products made from non-expanded polystyrene sheets. It is inferior to conventional molded products made from expanded polystyrene sheets. However, since the wall thickness of the molded product is thinner, the stack height is significantly smaller and superior to molded products made from conventional foamed polystyrene sheets. In addition, in terms of moldability, which takes into account ease of breakage during molding, it is slightly inferior to molded products using conventional foamed polystyrene sheets, but it is superior to products using non-foamed polystyrene sheets. . After all, when judged comprehensively, the molded product such as a tray obtained by the manufacturing method of the present invention is the most economical. Table 2 shows an example of the properties and composition of a polystyrene foam sheet when a tray (with ribs) was produced by setting various conditions using the same apparatus as in Example 1 and a good tray was obtained, together with a comparative example. Shown below. [Note] 1...Products obtained by cross punching (molding in which the longitudinal direction of the tray crosses the longitudinal direction of the sheet) are easily broken. However, it has sufficient strength in the case of flow casting (forming where the longitudinal direction of the tray and the longitudinal direction of the sheet match). [Note] 2...You can get it by hitting cross or flowing.

【table】

[Table] The product is easily broken. Not suitable for continuous production due to narrow molding cycle width. Poor moldability due to poor sheet elongation during molding. Also, due to the solvent effect of the foaming agent, some of the bubbles in the molded product are destroyed, resulting in weak strength.
Partial surface melting. [Note] 3...The molding cycle width is narrow and it is not suitable for continuous production. A large amount of heat is required during preheating, making it inefficient. Example 6 A molded article was manufactured using an apparatus similar to that shown in FIG. An extruder for adhesive (a mixture of butadiene-styrene resin and low-density polyethylene) (in Fig. 2,
19) and a high-density polyethylene extruder (corresponding to 17 in Figure 2) with a screw diameter of 90 mm.
Using a φ extruder (corresponding to 2 in Figure 2), 90 parts by weight of polystyrene (Styron-666) and 10 parts by weight of polystyrene containing 6% by weight of butadiene rubber (Idemitsu Styrene H150, Idemitsu Petrochemical Co., Ltd.) (manufactured by Kogyo Co., Ltd.) in a tumbler was melt-kneaded with foamed dichlorodifluoromethane at a mixture of 0.15 mol/kg, and then passed through a crosshead die with a slit interval of 0.45 mm and a die temperature of 0.15 mol/kg.
Extrusion foaming from a cylindrical die at 120℃, diameter 331mmφ
The foamed polystyrene sheet was cooled to a surface temperature of about 45° C. in the same manner as in Example 1 and then taken out through a cooling tube, thereby obtaining a foamed polystyrene sheet with a high-density polyethylene film laminated on one side via an adhesive. This sheet was heated to above the softening point of the polystyrene foam in a heating chamber equipped with an infrared heater at 430°C without aging in the same manner as in Example 1, and then press-molded at a molding cycle of 12 seconds and a press pressure of 1.5 tons. As a result, a desired tray similar to that shown in FIG. 3 measuring 190 x 97 x 15 mm was obtained. In addition, the results of continuous production of foamed polystyrene molded products with laminated films under various conditions are shown in Table 3 together with Example 6 as Examples 7 to 10. Note that in Example 10, lamination is not performed.

【table】

【table】

[Table] This is a comparative example of the case. In this way, laminated molded products have a low stack height and superior mechanical strength compared to non-laminated molded products, and are also beautiful as products, making them ideal for containers, trays, etc. It is useful as a variety of molded products such as partition underlays. Furthermore, by selecting an appropriate film, a molded product with controlled moisture permeability and gas permeability can be obtained, which is particularly useful as a food packaging material. In addition, it is advantageous in that deep-drawn containers can be easily obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing a specific example of an apparatus used in the continuous manufacturing method of expanded polystyrene molded products of the present invention. FIG. 2 is a schematic plan view showing a specific example of an apparatus used in the continuous production method of a foamed polystyrene molded product having a thermoplastic resin film layer according to the present invention. FIG. 3 is a plan view of a tray showing a specific example of a foamed polystyrene molded product obtained by the method of the present invention, FIG. 4 is a partial cross-sectional view of FIG. 3, and FIG. −
' cross-sectional view, Figure 6 is a -' cross-sectional view in Figure 3, Figure 7 is a partially enlarged view of Figure 4, Figure 8 is
The figure is a partially enlarged view of FIG. 6. 1, 16, 18...hopper, 2...extruder,
3...Blowing agent supply pipe, 3a...Blowing agent supply control device, 4...Cylindrical die, 4'...Crosshead die, 5...Cylindrical foam, 6...Cooling plug, 7
...Cutter knife, 8...Retrieval device, 8a...
... Take-up roll, 8b ... Step roll, 9 ... Polystyrene foam sheet, 10 ... Heating section, 10
a... Heater, 11... Feed chain, 12...
...Press molding section, 12a...Molding die, 13...
cutter, 14... conveyor, 15... assembly of molded products, 17... thermoplastic resin extruder, 19...
...Adhesive extruder, 101...Tray, 102...
Bottom wall, 103...Brim, 104...Surrounding wall, 10
5,109,110,112,114-121,
125...Rib.

Claims (1)

[Scope of Claims] 1 A polystyrene resin composition containing 0 to 20% by weight of a rubber component as a blend or copolymerization component based on the polystyrene resin and a foaming agent are extruded through a die of an extruder. The foam is uniaxially or biaxially stretched and cooled to give a bulk density of 0.15 to 0.7 g/cm ³ ,
Thickness: 0.3 to 1.0 mm, number of bubbles in the thickness direction: 5 to 20, residual gas amount of foaming agent: 0.03 to 0.3 mol/Kg, stretching ratio: 1.25
A polystyrene foam molded product, characterized in that a polystyrene foam molded product is obtained by forming the following polystyrene foam sheet and subsequently heating and molding the foam sheet into an arbitrary shape without subjecting it to substantial aging. continuous manufacturing method. 2. The manufacturing method according to claim 1, wherein the polystyrene resin is a polymer or copolymer whose main constituent unit is a styrene vinyl monomer such as styrene, methylstyrene, or dimethylstyrene. 3. The manufacturing method according to claim 2, wherein the molecular weight of the polymer or copolymer is 5×10 ⁴ to 70×10 ⁴ as a weight average molecular weight determined by GPC method. 4 The rubber component contained as a blend component is
The manufacturing method according to any one of claims 1 to 3, comprising butadiene rubber, ethylene-propylene rubber, styrene-butadiene rubber, or polyethylene. 5. The manufacturing method according to any one of claims 1 to 3, wherein the rubber component contained as a copolymerization component consists of butadiene, isoprene, or chloroprene. 6. The manufacturing method according to any one of claims 1 to 5, wherein the polystyrene composition contains a rubber component in an amount of 0.3 to 15% by weight based on polystyrene. 7. The manufacturing method according to any one of claims 1 to 5, wherein the polystyrene composition contains a rubber component in an amount of 0.3 to 5.0% by weight based on the polystyrene. 8. Claims 1 to 8, wherein the blowing agent is a volatile blowing agent such as propane, butane, pentane, trichloromonofluoromethane, dichlorodifluoromethane, 1,2-dichlorotetrafluoroethane, or a mixture of two or more thereof. The manufacturing method according to any of Item 7. 9. The manufacturing method according to claim 8, wherein the volatile blowing agent is used in an amount of 0.03 to 0.4 mol/Kg based on the polystyrene resin in the polystyrene resin composition. 10 In the polystyrene resin composition, talc,
The manufacturing method according to any one of claims 1 to 9, wherein a cutting agent such as sodium hydrogen carbonate, ammonium hydrogen carbonate, calcium carbonate, clay, or citric acid is included. 11. A polystyrene resin composition containing 0 to 20% by weight of the polystyrene resin as a blend or copolymerization component of a rubber component and a foaming agent are supplied to an extruder, and (a) a thermoplastic resin film layer is placed in a die. The laminated foam obtained by extruding through a die while being laminated is cooled while being uniaxially or biaxially stretched, or (b) The foam obtained by extruding from a die is cooled while being uniaxially or biaxially stretched, and a thermoplastic resin is formed. By laminating film layers, foaming can be achieved with a bulk density of 0.15 to 0.7 g/cm ³ , a thickness of 0.3 to 1.0 mm, a number of bubbles in the thickness direction of 5 to 20, a residual gas amount of 0.03 to 0.3 mol/Kg, and a stretching ratio of 1.25 or less. A polystyrene foam molded product is obtained by obtaining a composite sheet made by laminating a thermoplastic resin film on at least one side of a polystyrene sheet, and then heating and molding the composite sheet into an arbitrary shape without substantially subjecting it to aging. 1. A continuous manufacturing method for polystyrene foam molded products, characterized in that: 12. The manufacturing method according to claim 11, wherein the thermoplastic resin used for the thermoplastic resin film is polystyrene, high-impact polystyrene, polyethylene, polypropylene, or polyethylene terephthalate. 13 The thickness of the thermoplastic resin film layer is about 5~
Claim 11 or 1 which is 300 μm
The manufacturing method according to item 2.