JP2012011639A - Foamed polystyrene resin sheet, foamed polystyrene resin laminated sheet, molding formed from laminated sheet, and method for producing foamed polystyrene resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foamed polystyrene resin laminated sheet for forming a molding excellent in printability onto a surface (curved surface) after molding and good in appearance, a molding formed by using the laminated sheet, and a method for producing the molding.SOLUTION: A foamed polystyrene resin sheet 12 is formed by using a polystyrene resin composition containing 10 to 50 pts.mass of a polyphenylene ether resin to 100 pts.mass of the total of the polystyrene resin and the polyphenylene ether resin. The length of a whole region in the width direction perpendicular to the longitudinal direction is 650 mm or above, and an average thickness of the whole region in the width direction is 1-3 mm. The ratio between the average of thicknesses of the width of 150 mm at an arbitrary position in the width direction and the average of thicknesses of the while region in the width direction is in a range of 0.90-1.10. The density of the whole is 0.2 g/cmor below, and the density of a part to 100 μm in the thickness direction from at least one surface is 0.25 g/cmor above.

Description

  The present invention relates to a foamed polystyrene-based resin laminated sheet widely used in food containers and the like, and in particular, a polystyrene-based resin foamed sheet for forming a foamed polystyrene-based resin laminated sheet and a molding formed using the foamed polystyrene-based resin laminated sheet. Product and a method for producing a polystyrene-based resin foam sheet.

  Conventionally, as a food container or a packaging material, a foamed polystyrene-based resin laminated sheet molded into a predetermined shape has been widely used (see Patent Document 1 below). Containers formed by molding these expanded polystyrene-based resin laminate sheets are strongly required to have a beautiful appearance. Furthermore, in applications such as for instant foods, it is required that printing can be performed by directly applying ink to the surface (curved surface). Therefore, it is important that good printing is possible.

  Therefore, in order to obtain a container having good printability, as shown in FIG. 5, cooling is performed by ejecting the surface of the polystyrene resin foam sheet 2 extruded from the die 1 from the nozzle 3 during extrusion foam molding. A foamed polystyrene-based resin laminate sheet is known in which the surface layer of the polystyrene-based resin foam sheet 2 is densified by cooling with gas (air) and a non-expanded polystyrene resin film is laminated on the surface thereof. Such a foamed polystyrene-based resin laminated sheet has a surface on the non-foamed polystyrene-based resin film side because fine bubbles having a major axis of 50 μm or less are formed on the boundary side of the polystyrene-based resin foamed sheet with the non-foamed polystyrene-based resin film. It becomes possible to form a container with good printability.

JP 2003-154571 A

However, since there is a correlation between the density and thickness uniformity of the foam sheet 2, the flow rate of the cooling gas ejected from the nozzle 3 when the surface layer portion of the foam sheet 2 is densified as described above. There is a possibility that the density of the surface layer portion changes due to the change of the thickness, and the thickness of the foam sheet 2 becomes non-uniform. Such non-uniform thickness causes a trouble when laminating a non-foamed polystyrene resin film in a subsequent process, or causes a molding defect when molding a molded product. Moreover, since the thickness of the obtained laminated sheet is also non-uniform, it becomes a factor such as reducing the strength of a molded product molded using such a laminated sheet.
In recent years, it has been studied to improve the heat resistance of a polystyrene resin foam sheet by containing a polyphenylene ether resin, and such a polystyrene resin foam sheet or a laminate using the polystyrene resin foam sheet is used. With respect to the sheet, little countermeasures have been taken for the above problems.

  Accordingly, the present invention provides a foamed polystyrene-based resin laminate sheet that is excellent in printability on the surface (curved surface) after molding and can provide a molded product with a beautiful appearance, and a molded product formed using such a laminate sheet. And providing a method for producing a polystyrene resin foam sheet and a polystyrene resin foam sheet for forming such a laminated sheet.

As a result of intensive studies to achieve the above object, the present inventors contain a polystyrene resin and a polyphenylene ether resin, and a total of 100 parts by mass of the polystyrene resin and the polyphenylene ether resin. A polystyrene system having a thickness of 1 to 3 mm and a density of 0.2 g / cm ³ or less formed using a polystyrene resin composition containing the polyphenylene ether resin in a proportion of 10 parts by mass to 50 parts by mass. For the resin foam sheet, the thickness variation across the width direction orthogonal to the longitudinal direction is less than a certain value, and the ratio between the average thickness value at 150 mm width at any position in the width direction and the average thickness value across the width direction. It has been found that if is within a certain range, it will not cause troubles and molding defects in the subsequent process. Thus, the gist of the polystyrene-based resin foam sheet according to the present invention is that the length in the entire width direction is 650 mm or more, the average thickness in the entire width direction is 1 to 3 mm, and at any position in the width direction. The ratio of the average value of the thickness at 150 mm width and the average value of the thickness in the entire width direction is in the range of 0.90 to 1.10, and the overall density is 0.2 g / cm ³ or less, The density of the portion from one surface to the thickness direction of 100 μm is 0.25 g / cm ³ or more.

Furthermore, if a predetermined film is laminated from the surface of the polystyrene resin foam sheet to the surface where the density in the thickness direction 100 μm portion is a certain value or more, a molded product having good surface (curved surface) printability can be obtained. I found it. Therefore, the gist of the expanded polystyrene-based resin laminate sheet according to the present invention is that the density of the portion from the surface of the polystyrene-based resin expanded sheet to the thickness direction of 100 μm is 0.25 g / cm ³ or more and the thickness is 50 That is, a non-foamed resin film of ˜300 μm is laminated.

  Further, in the production of the polystyrene resin foam sheet, the flow of the cooling gas has a great influence on the uniformity of the thickness of the foam sheet, the flow of the cooling gas is disturbed, or the foam sheet in the softened state immediately after the extrusion It has been found that the thickness becomes non-uniform when the pressure from the cooling gas increases locally. Furthermore, in a method of continuously producing an extruded foam sheet from a die after melt-mixing a polystyrene resin and a foaming agent in an extruder, a cooling gas is blown onto the foam sheet under a certain condition, thereby cooling gas. It has been found that the sheet surface can be cooled without disturbing the flow of the sheet and with the pressure applied to the foamed sheet in the softened state kept low. As a result, it was found that a polystyrene resin foam sheet having a uniform thickness of the foam sheet and a sufficiently high density of the surface layer portion can be obtained.

  Then, the place made into the summary of the manufacturing method of the polystyrene-type resin foam sheet which concerns on this invention contains a polystyrene-type resin and a polyphenylene ether-type resin, and is a total of 100 mass parts of the said polystyrene-type resin and the said polyphenylene ether-type resin. The polystyrene-based resin composition containing the polyphenylene ether resin in a proportion of 10 parts by mass or more and 50 parts by mass or less and the foaming agent are melt-kneaded in an extruder, and then the extruded foam sheet is formed using a die. In the continuous production method, the surface of the foamed sheet is cooled by blowing a cooling gas onto the surface of the extruded foam sheet so as to form a flow along the surface of the foamed sheet.

  As described above, according to the present invention, it is possible to obtain a molded article that is excellent in printability on the surface (curved surface) after molding and has a beautiful appearance.

The principal part expanded sectional view which shows one structure of the expanded polystyrene-type resin laminated sheet which concerns on this invention. Sectional drawing which shows an example of the molded article shape | molded using the expanded polystyrene-type resin laminated sheet which concerns on this invention. The principal part cross-section explanatory drawing which shows an example of the manufacturing apparatus of the polystyrene-type resin foam sheet which concerns on this invention. The principal part cross-section explanatory drawing which shows the further another example of the manufacturing apparatus of the polystyrene-type resin foam sheet which concerns on this invention. It is principal part cross-sectional explanatory drawing which shows the example of the manufacturing apparatus of the conventional polystyrene-type resin foam sheet.

  Hereinafter, a polystyrene resin foam sheet, a foamed polystyrene resin laminate sheet, a method for producing a polystyrene resin foam sheet, and a molded product formed from the foamed polystyrene resin laminate sheet according to the present invention will be described with reference to the drawings. As shown in FIG. 1, the expanded polystyrene-based resin laminated sheet 10 according to the present invention is configured by laminating a non-expanded polystyrene-based resin film 14 on one surface of a polystyrene-based resin expanded sheet 12 by heat fusion.

  Moreover, as shown in FIG. 2, the container 16 which is an example of the molded article which concerns on this invention heat-processes said foamed polystyrene-type resin laminated sheet 10 at the temperature of about 130 to 160 degreeC, for example. After being subjected to secondary foaming and plasticization, it is obtained by molding by a known method such as press molding or vacuum molding so that the non-foamed polystyrene resin film 14 is outside the container.

  The polystyrene resin foam sheet 12 is formed using a polystyrene resin composition containing a polystyrene resin and a polyphenylene ether resin. As the polystyrene resin, polystyrene, impact-resistant polystyrene, styrene-maleic anhydride copolymer, styrene-acrylic acid ester copolymer, or the like is used.

Further, the polyphenylene ether resin in the present invention is effective for imparting heat resistance, and is 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass in total of the polystyrene resin and the polyphenylene ether resin. Contained in proportions.
In addition, polyphenylene ether-type resin is normally represented by the following general formula.

Here, R ¹ and R ² represent an alkyl group having 1 to 4 carbon atoms or a halogen atom, and n is a positive integer representing the degree of polymerization.
For example, poly (2,6-dimethylphenylene-1,4-ether), poly (2,6-diethylphenylene-1,4-ether), poly (2,6-dichlorophenylene-1,4-ether) Ether) or the like may be used in this embodiment.
The degree of polymerization n is usually in the range of 10 to 5000.

Such a polyphenylene ether resin is effective for improving heat resistance, but the polyphenylene ether resin is used in an amount of 10 parts by mass or more and 50 parts by mass or more with respect to 100 parts by mass in total of the polystyrene resin and the polyphenylene ether resin. It is preferable to contain it in a proportion of less than or equal to parts by mass. If the amount is less than the above range, the addition effect of the polyphenylene ether resin may not be sufficiently exerted, and conversely, the polyphenylene ether resin is contained beyond the above range. This is because there is a possibility that the effect of adding the polyphenylene ether resin will not be exhibited even if it is made to be.
Moreover, since it is generally more expensive than a polystyrene resin, if the polyphenylene ether resin is contained beyond the above range, there is a possibility of causing a problem in terms of material cost.

  Usually, the Vicat softening temperature of polystyrene resin (JIS K7206-1991, Method B, 50 ° C./h) is about 102 ° C., but by including the polyphenylene ether resin as described above, the Vicat softening temperature is reduced. It can be improved to a range of 110 to 155 ° C., and by using a polystyrene resin composition containing the polyphenylene ether resin, the resulting polystyrene resin foam sheet and the polystyrene resin foam sheet are subjected to secondary processing. It is possible to improve the heat resistance of manufactured products.

In general, when heat resistance is required for a product in which a polystyrene resin composition is used, a styrene-methacrylic acid copolymer, styrene-maleic anhydride copolymer, styrene having a higher Vicat softening temperature than a styrene homopolymer -Copolymers such as maleimide copolymer and polyparamethylstyrene resin are employed as the forming material.
On the other hand, the method of blending the polyphenylene ether-based resin as described above is excellent not only in imparting heat resistance to the product but also in imparting excellent toughness.

  Therefore, when a foamed tray or the like is formed using a polystyrene resin composition containing a polyphenylene ether resin, it is possible to form a foamed tray that does not crack even if sudden deformation is applied.

However, since the polyphenylene ether-based resin has a peculiar odor, it is preferable to contain a component for deodorization particularly in applications where odor is hated.
Examples of the deodorant component include zeolite-based and zirconium phosphate-based inorganic particles.
Especially, it is preferable to employ | adopt a zirconium phosphate type component in the point of the deodorizing effect.

The polystyrene-based resin foam sheet 12 has a width in the entire width direction (hereinafter referred to as a full width) perpendicular to the longitudinal direction of 650 mm or more, an average thickness in the full width of 1 to 3 mm, and an arbitrary width direction. The ratio of the average value of the thickness at 150 mm width and the average value of the thickness at the full width is in the range of 0.90 to 1.10, and the overall density is 0.2 g / cm ³ or less. What has the density of the part (henceforth a surface part) from the surface laminated | stacked with a foamed polystyrene-type resin film to 100 micrometers in the thickness direction is 0.25 g / cm < ³ > or more is used. Further, this polystyrene-based resin foam sheet 12 is used in particular having a thickness variation of 0.35 mm or less in the width direction.

  Here, the thickness variation in the width direction, and the ratio of the average value of the thickness of 150 mm width to the average value of the thickness across the entire width are measured at regular intervals in the width direction using a commonly used measuring machine such as a contact-type thickness meter. It is calculated | required from the result measured by (for example, 2 cm space | interval). If the thickness variation over the entire width is greater than 0.35 mm and the ratio of thickness average values is greater than 1.10 or less than 0.90, it may cause trouble in the steps described later. In addition, when the thickness variation in the entire width is smaller than 0.35 mm and the ratio of thickness average value is larger than 1.10 or smaller than 0.90, a trouble occurs in the subsequent process and is stable. Cannot be manufactured. When the laminated sheet 10 formed by laminating the non-expanded polystyrene resin film 14 on the foamed sheet 12 having a non-uniform thickness is molded into the container 16, defective molding occurs or the strength of the thin part is reduced. Problem arises.

Further, the density of the 100 μm portion in the thickness direction from the surface on which the non-foamed polystyrene resin film 14 is laminated is obtained by cutting out the relevant portion and measuring the volume and weight. When this density is smaller than 0.25 g / cm ³ , a sufficient amount of fine bubbles is not generated at the stage of forming the container 16, so that good printability cannot be obtained. On the other hand, the base resin of the non-expanded polystyrene resin film 14 may be any resin that can be heat-sealed with the polystyrene resin foam sheet 12, and similarly polystyrene, impact-resistant polystyrene, styrene-maleic anhydride copolymer. A styrene-acrylic acid ester copolymer or the like is used.

Next, a method for producing a polystyrene resin foam sheet and a foamed polystyrene resin laminate sheet will be described. First, the polystyrene resin foam sheet 12 is supplied with the above polystyrene resin composition to an extruder, heated, melted and kneaded in the extruder, then injected with a foaming agent, as shown in FIG. Extruded in a circular shape from a circular die 18 attached to the tip of the extruder and formed into a circular shape with a thickness of 1 to 3 mm and a density of 0.2 g / cm ³ or less.

The conditions for extrusion foaming are as follows. In the extruder, the polystyrene resin composition is melted by heating to a range of 170 ° C. to 300 ° C., and a foaming agent is injected, and then it is cooled to 70 ° C. to 200 ° C. It is desirable to supply and extrude to the circular die 18 at a pressure of 150 to 400 kg / cm ² while adjusting the temperature. If the temperature of the molten resin is 200 ° C. or higher, the viscosity of the resin becomes too low and the bubbles are destroyed, and if the temperature is 70 ° C. or lower, sufficiently large bubbles cannot be formed. In other words, unless the viscosity of the molten resin is within an appropriate range, foaming cannot be performed, and foamed bubbles cannot be stopped in the resin.

  As the extruder used here, any apparatus generally used in this field can be used, but a tandem extruder is used to melt the polystyrene resin composition in the first stage and press-fit a foaming agent. It is desirable to perform cooling in the second stage. The cooling of the surface of the polystyrene-based resin foam sheet 20 extruded from the extruder can be realized, for example, by the apparatus shown in FIG. First, in the annular foam sheet 20 that is not sufficiently foamed immediately after being extruded from the circular die 18, that is, in the middle of foaming, the cooling gas is substantially parallel to the surface of the foam sheet 20 from the annular nozzle 22. The one side surface is rapidly cooled. This cooling gas is supplied through a supply pipe 24 from a supply hole 26 provided at the tip thereof, and blown out from a nozzle 22 formed between the end face of the circular die 18 and the end of the conical hood 28. The The cooling gas blown out from the nozzle 22 flows substantially parallel to the surface of the foam sheet 20 and is then exhausted to the outside through an exhaust pipe 32 disposed in the sizing device 30. On the other hand, the annular foamed sheet 20 is expanded in diameter by a sizing device 30 disposed downstream, and then divided into two semicircles and wound into a roll by a winder (not shown).

  By this cooling step, foaming of the cooled surface portion of the foam sheet 20 is suppressed, and the density of the portion remains almost constant or slightly reduced. Further, the foaming is promoted and the density is lowered as the foam sheet 20 is moved to the opposite surface where the foam sheet 20 is not cooled. Normally, pressurized air is used as the cooling gas. The temperature of the cooling gas may be lower than the temperature of the sheet surface immediately after extrusion, and a temperature of 100 ° C. or less is preferable. The cooling gas blown by using such an apparatus forms a flow parallel to the surface of the foam sheet 20, and the flow of the cooling gas is not disturbed, and the foam sheet 20 is locally pressurized by the cooling gas. Since it does not receive, the foamed sheet 20 with uniform thickness can be obtained.

  The foamed sheet 20 wound in a roll by a winder is cured at a temperature of 35 ° C. or lower, preferably 20-30 ° C. for 7-60 days, preferably 10-45 days, and then extrusion lamination. By laminating the non-expanded polystyrene resin film 14 having a thickness of 50 to 300 μm, the expanded polystyrene resin laminate sheet 10 is obtained.

  If this curing process is described in more detail, the intrusion of air into the bubbles inside the foam sheet 20 and the dissipation of the foaming agent gas remaining inside the foam sheet 20 are performed by the curing process. That is, the step of laminating the non-foamed film 14 on the foamed sheet 20 and taking the air necessary for the foamed sheet 20 after curing to exhibit secondary foaming ability into the bubbles, and the obtained laminated sheet 10 In the molding step, it is necessary to reduce the amount of the foaming agent remaining on the surface of the foam sheet 20 to the extent that the foam layer on the side on which the film is laminated does not break, and curing is performed to satisfy this condition. The

  This curing process is carried out in a form in which the foamed sheet 20 is rolled up. At this time, the foamed sheet 20 contracts due to relaxation of distortion during extrusion foaming and dissipation of the residual foaming agent. At that time, the thick part of the foam sheet 20 does not shrink so much, and the thin part shrinks well. As a result, if the thickness in the width direction of the foamed sheet 20 is not uniform, a difference occurs in the sheet length in the width direction between the thick part and the thin part. When the difference in sheet length becomes large, the foamed sheet 20 meanders in the next lamination process, and the non-foamed film 14 protrudes from the foamed sheet 20 or from the roll. In some cases, a part of the foamed sheet 20 may be lifted and a portion that cannot be laminated is generated. In a severe case, troubles such as bending of the foamed sheet on the line may occur.

  The thickness variation of the foam sheet 20 will be described in more detail. In a general polystyrene-based resin foam sheet 20, irregularities with a width of several centimeters to several tens of centimeters exist in the thickness pattern. The thickness variation (difference between the maximum value and the minimum value) in the thickness pattern is usually a value exceeding 0.35 mm.

  When the unevenness having a short width is dominant in the thickness distribution, the thickness difference is relieved by the rigidity of the foamed sheet 20, and the nonuniform shrinkage is reduced. However, when wide unevenness is dominant, the thickness difference cannot be relaxed and shrinkage nonuniformity occurs. This can be quantified by the ratio of the average thickness across the width and the average thickness 150 mm wide at any position in the width direction. When the ratio of the average thickness of the entire width to the average thickness of an arbitrary 150 mm width in the width direction is larger than 1.10 or smaller than 0.90, the above-described shrinkage of the foamed sheet 20 is not caused. The difference in the length of the foamed sheet 20 due to the uniformity becomes serious and causes the aforementioned process trouble.

  Moreover, when the whole thickness dispersion | variation is larger than 0.35 mm, the intensity | strength of the shape | molded molded object becomes low in a thin part. Therefore, considering the strength of the molded product, the overall thickness variation needs to be 0.35 mm or less. As described above, this curing is an important process for determining the secondary foaming ability of the polystyrene-based resin foam sheet 20, and the sheet contracts due to the dissipation of gas in the foam sheet 20. When the thickness of the polystyrene-based resin foam sheet 20 is not uniform, that is, when the thickness variation is larger than 0.35 mm, or when the ratio of thickness average values is larger than 1.10, or the ratio of thickness average values is 0.90. When smaller, the shrinkage | contraction of the polystyrene-type resin foam sheet 20 becomes non-uniform | heterogenous, and a difference arises in the sheet | seat length in the width direction. Thus, when a difference arises in the length of the foamed sheet 20 in the width direction, wrinkles are generated in the sheet or film in the extrusion lamination step, and a good laminated sheet 10 cannot be obtained.

  As described above, the polystyrene resin foam sheet according to the present invention, the foamed polystyrene resin laminate sheet, the molded product formed using the foamed polystyrene resin laminate sheet, and the method for producing the polystyrene resin foam sheet have been described. The invention is not limited to the embodiment described above. In addition, the same location as the above-mentioned embodiment attaches | subjects the same code | symbol to drawing, and abbreviate | omits description. For example, as shown in FIG. 4, if necessary, the inner surface of the annular foam sheet 20 may be cooled, and at the same time, the outer surface may be cooled by blowing a cooling gas by a similar method. That is, an annular nozzle 36 is provided along the outer periphery of the circular die 18. With this configuration, the annular foam sheet 38 extruded from the circular die 18 has a structure in which foaming is suppressed not only on the inner surface but also on the outer surface, the inner and outer surface portions are high in density, and the internal density is low. On one side of the obtained foamed sheet 38, after curing under certain conditions, the non-foamed polystyrene resin film 14 is laminated.

Here, the high density portion formed on at least one surface of the foamed sheets 20 and 38 needs to have a density of at least a portion from the surface to the thickness direction of 100 μm being 0.25 g / cm ³ or more. It can be controlled by the temperature and flow rate of the cooling gas. Further, as shown in FIG. 3 and the like, the space 38 surrounded by the circular die 18, the polystyrene resin foam sheet 20 extruded therefrom, and the sizing device 30 forms a sealed space. Therefore, the amount of cooling air ejected from the nozzle 22 and the amount of air discharged from the exhaust pipe 32 are controlled, and the internal pressure of the space 38 is set to be higher than the external air pressure, so that the polystyrene resin foam sheet 20 has wrinkles. It is preferable not to occur.

  As mentioned above, although the polystyrene-type resin foam sheet and foamed polystyrene-type resin laminated sheet which concern on this invention, and those manufacturing methods were demonstrated, it is not limited to these. Moreover, it is preferable to shape | mold into containers, such as a bowl and a bowl-shaped container, a dish, as a molded article shape | molded with an expanded polystyrene-type resin laminated sheet. In addition, the present invention can be implemented in variously modified, modified, and modified forms based on the knowledge of those skilled in the art within a range that does not depart from the gist of the present invention, such as making the extrusion direction of the manufacturing apparatus vertical. These belong to the scope of the present invention.

<Example 1>
Polystyrene resin (GPPS (styrene homopolymer) manufactured by DIC, trade name “XC-515”) and a mixed resin of polyphenylene ether resin (PPE) and polystyrene resin (PS) (trade name “manufactured by Subic,” A polystyrene resin composition containing 30 parts by mass of the mixed resin (Noryl EFN4230) with respect to a total of 100 parts by mass of “Noryl EFN4230”, PPE / PS = 70/30) is supplied to a tandem extruder. Then, after melting at a temperature of 270 ° C. in the first stage extruder, a foaming agent is injected, cooled to 105 ° C. in the second stage extruder, extruded from the circular die 18 and foamed, and the width direction the thickness of the average in the entire 2.00 mm, density 0.12 g / cm ^3, expansion ratio 8.8 times, the total width 1045Mm, length 300m Police To obtain a lens-based resin foam sheet 20.
This extrusion foam molding is performed by blowing air at a temperature of 30 ° C. at a rate of 1.7 m ³ / min substantially parallel to the surface of the foam sheet 20 extruded from the circular die 18 using the apparatus shown in FIG. A densified layer (unfoamed layer) was formed on the surface of the sheet 20. Then, after the extruded foam sheet 20 is wound up and cured at a temperature of 25 ° C. for 20 days, a non-foamed impact-resistant polystyrene system having a thickness of 130 μm is formed by extrusion lamination on the surface of the foam sheet 12 (20) on the non-foamed layer side. The resin film 14 was laminated | stacked and the expanded polystyrene-type resin laminated sheet 10 was obtained.

  Moreover, the obtained expanded polystyrene-type resin laminated sheet 10 was shape | molded so that the film 14 might become the outer side of a container, and the container of the shape shown in FIG. 2 was obtained.

In addition, about the polystyrene-type resin foam sheet 12, the thickness variation of the whole width, the ratio of the thickness average value of an arbitrary 150 mm width in the width direction and the thickness average value in the whole width, the overall density, the density of the surface portion (one side) The density of the portion in the thickness direction of 100 μm from the surface of the container was measured, and the container was printed on the outer side surface. Each result is as shown in Table 1.
At this time, regarding the thickness variation of the entire width, the thickness of the foamed sheet was measured by using a “thickness measuring device” (model: SM-125) manufactured by Teclock Co. in any 21 locations in the width direction, and the average thickness was obtained by arithmetic mean. The average thickness at an arbitrary 150 mm width was calculated by measuring the thickness at three locations in the same manner.
Moreover, about the whole density, it measures based on JISK7222: 2005 "how to obtain a foamed plastic and rubber-apparent density", About the density of a surface part, a foam sheet is 0.1 mm in depth from the surface. After slicing, the density of the sliced pieces was determined in the same manner as the overall density.

<Example 2>
In the method for producing the polystyrene-based resin foam sheet 20 shown in Example 1, the same except that the air volume of the cooling air blown onto the surface of the foam sheet 20 extruded from the circular die 18 was set to 2.1 m ³ / min. Foam sheet 12 (20) was manufactured under the conditions. Furthermore, the expanded polystyrene type resin laminated sheet 10 and the container were obtained.

  As in Example 1, for the polystyrene-based resin foam sheet 12, the thickness variation of the entire width, the ratio of the thickness average value of any 150 mm width in the width direction to the thickness average value of the entire width, the surface portion The density was measured, and the container was printed on the outer side. Each result is as shown in Table 1.

<Comparative Example 1>
A polystyrene-based resin foam sheet 12 was manufactured under the same conditions as in Example 1 except that the surface cooling gas was blown at a flow rate of 1.0 m ³ / min using the conventional apparatus shown in FIG. And using the obtained polystyrene-type resin foam sheet 12, the expanded polystyrene-type resin laminated sheet and also the container were obtained on the conditions similar to Example 1. FIG.

  As in Example 1, for the polystyrene-based resin foam sheet 12, the thickness variation of the entire width, the ratio of the thickness average value of any 150 mm width in the width direction to the thickness average value of the entire width, the surface portion The density was measured, and the container was printed on the outer side. Each result is as shown in Table 1. In this conventional apparatus, the cooling gas is blown almost perpendicularly to the surface of the foamed sheet 2 lacking self-supporting immediately after extrusion, and the cooling gas is greatly disturbed immediately after colliding with the sheet 2 and the cooling gas collides. Since the foamed sheet was locally subjected to a large pressure at the part, the thickness became non-uniform. Therefore, a sheet having a uniform thickness and a sufficiently high surface layer density could not be obtained.

<Comparative example 2>
A polystyrene resin foam sheet 12 was produced under the same conditions as in Example 1 except that the surface cooling gas was blown at a flow rate of 1.7 m ³ / min using the conventional apparatus shown in FIG. The obtained foamed sheet 2 is wound up, cured at a temperature of 25 ° C. for 20 days, and then extruded to the surface of the foamed sheet 2 (12) on the non-foamed layer side, and 130 μm of non-foamed impact-resistant polystyrene. The system resin film 14 was laminated. At this time, wrinkles were generated in the sheet, and a good expanded polystyrene-based resin laminate sheet 10 could not be obtained.

  As in Example 1, for the polystyrene-based resin foam sheet 12, the thickness variation of the entire width, the ratio of the thickness average value of any 150 mm width in the width direction to the thickness average value of the entire width, the surface portion The density was measured, and the container was printed on the outer side. Each result is as shown in Table 1.

  Since the polystyrene-based resin foam sheet according to the present invention is configured under a certain condition, the above-described process trouble does not occur when a non-expanded polystyrene-based resin film is laminated on the surface of the foam sheet. In addition, since molding does not cause defective molding when molding the container, stable production becomes possible.

Further, a non-foamed polystyrene resin film is laminated on the surface of a polystyrene resin foam sheet having a density of at least 0.25 g / cm ^{3 in the} thickness direction of 100 μm from at least one surface to constitute a foamed polystyrene resin laminate sheet. Therefore, good surface (curved surface) printability was obtained for a molded product molded using such a laminated sheet.

  Further, in the method for producing a polystyrene-based resin foam sheet, a cooling gas having a temperature lower than the temperature of the extruded foam sheet is blown so as to form a flow along the surface of the foam sheet, so that the surface of the foam sheet is formed. Because it is cooled, the sheet surface can be cooled without disturbing the flow of the cooling gas and the pressure to the foamed sheet in the softened state is low, the thickness of the foamed sheet is uniform, and the density of the surface layer part is sufficient A high polystyrene resin foam sheet could be obtained.

<Reference example>
Below, the resin component is cracked in a polystyrene resin foam sheet made of a polystyrene resin composition of a styrene resin alone and a polystyrene resin foam sheet made of a polystyrene resin composition containing a polyphenylene ether resin. The example which evaluated difficulty is shown.

(Sheet 1)
70% by mass of a polystyrene resin (GPPS (styrene homopolymer) manufactured by DIC, trade name “XC-515”), and a mixed resin of polyphenylene ether resin (PPE) and polystyrene resin (PS) (manufactured by Subic) , Zirconium phosphate deodorant manufactured by Toa Gosei Co., Ltd. as a deodorizing component (trade name “Product name“ Noryl EFN4230 ”, PPE / PS = 70/30) Kesumon NS-10 ") by extrusion foaming the resin composition containing 0.5 parts by mass, thickness 2.0 mm, the foamed sheet having a basis (basis weight) 180 g / m ² was produced.

(Sheet 2)
Instead of a resin composition containing GPPS, PPE, and a deodorizing component, a copolymer of an acrylic monomer and a styrene monomer is extruded and foamed, and a polystyrene resin foam sheet (sheet 2) having the same thickness and the same basis weight as the sheet 1 ) Was produced.

(Sheet 3)
Instead of the resin composition containing GPPS, PPE, and deodorant components, only GPPS was extruded and foamed to produce a polystyrene resin foam sheet (sheet 3) having the same thickness and the same basis weight as sheet 1.

(Heat resistance evaluation: differential scanning calorimetry)
A sample of 6.5 ± 0.5 mg was taken from the above sheet, and differential scanning calorimetry was performed based on JIS K7121 (device used: differential scanning calorimeter, manufactured by SII Nanotechnology, model name “DSC6220” ").
As a result, in the samples of Sheet 1 and Sheet 2, the “midpoint glass transition temperature (Tmg)” described in JIS K7121 9.3 (1) was observed around 120 ° C., and in the sample of Sheet 3, 106 ° C. Observed.

(Toughness evaluation: Dynatap impact test)
A 100 × 100 mm test piece was collected from the sheets 1 to 3 and subjected to a Dynatap impact test based on ASTM D3763 on the test piece (device used: General Research Corp., Dynatap impact) Test device, model name “GRC8250”).
As a result, for the test piece of the sheet 2, the maximum point displacement was 3.2 mm and the maximum load was 29 N, and for the test piece of the sheet 3, the maximum point displacement was 4.0 mm and the maximum load was 36 N.
On the other hand, for the test piece of the sheet 1, the maximum point displacement was 4.4 mm and the maximum load was 42 N.
Also from this, it can be seen that the sheet 1 is in a state in which displacement and load are difficult to crack due to containing the PPE resin.

DESCRIPTION OF SYMBOLS 10 ... Expanded polystyrene-type resin laminated sheet, 12, 20 ... Polystyrene-type resin foam sheet, 14 ... Non-expanded polystyrene-type resin film, 16 ... Container (molded article), 18 ... Circular die, 22, 36 ... Nozzle, 24 ... Supply Air pipe, 30 ... Sizing device, 32 ... Exhaust pipe

Claims (6)

It contains a polystyrene-based resin and a polyphenylene ether-based resin, and the polyphenylene ether-based resin is 10 parts by mass or more and 50 parts by mass or less with respect to a total of 100 parts by mass of the polystyrene-based resin and the polyphenylene ether-based resin. A polystyrene resin foam sheet formed using a contained polystyrene resin composition,
The length of the entire width direction orthogonal to the longitudinal direction is 650 mm or more, the average thickness in the entire width direction is 1 to 3 mm, the average value of the thickness at 150 mm width in any position in the width direction and the entire width direction The ratio of the thickness to the average value is in the range of 0.90 to 1.10, the overall density is 0.2 g / cm ³ or less, and the density of the portion from at least one surface to the thickness direction of 100 μm is A polystyrene-based resin foamed sheet characterized by being at least 0.25 g / cm ³ .   The polystyrene-based resin foam sheet according to claim 1, wherein thickness variation in the width direction is 0.35 mm or less. A non-foamed resin film having a thickness of 50 to 300 μm is formed on the surface of the polystyrene-based resin foam sheet according to claim 1 or 2 having a density of 0.25 g / cm ³ or more from the surface to the thickness direction of 100 μm. A foamed polystyrene-based resin laminate sheet characterized by being laminated.   The expanded polystyrene-based resin laminated sheet according to claim 3, wherein the non-expanded resin film is a non-expanded polystyrene-based resin film.   A molded product obtained by molding the expanded polystyrene-based resin laminated sheet according to claim 3 or 4 into a suitable shape.   It contains a polystyrene-based resin and a polyphenylene ether-based resin, and the polyphenylene ether-based resin is 10 parts by mass or more and 50 parts by mass or less with respect to a total of 100 parts by mass of the polystyrene-based resin and the polyphenylene ether-based resin. In the method of continuously producing an extruded foam sheet using a die after melt-kneading the contained polystyrene resin composition and the foaming agent in an extruder, a cooling gas is applied to the surface of the extruded foam sheet. A method for producing a polystyrene-based resin foam sheet, wherein the foam sheet is sprayed so as to form a flow along the surface of the foam sheet to cool the surface of the foam sheet.

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