JPH09272165A - Foamed polystyrene sheet laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foamed polystyrene sheet laminate which gives a molding with good curved surface printability. SOLUTION: In a laminate 50-600g/m<2> in basis weight and 0.10-0.25g/cm<3> in density in which a synthetic resin is laminated at least on one side of a foamed polystyrene sheet, the compressive deformation is not exceeding 0.5mm when pressure of 4kg/cm<2> is applied vertically after secondary expansion to minimize the density, and the center line average roughness of the surface on which curved-surface printing is implemented is not exceeding 15μm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polystyrene resin foam sheet laminate having a synthetic resin laminated on one side or both sides thereof, and particularly has excellent printability in curved surface printing when thermoformed as a container. It also relates to a polystyrene resin foam sheet laminate.

[0002]

2. Description of the Related Art Foamed synthetic resin sheets are used in various fields such as containers for instant cooking food such as trays and bowls, and in particular, polystyrene resin having excellent moldability and economical advantages. Foamed sheets are used in large quantities. As a method for producing such a synthetic resin foam sheet, an extrusion foam molding method has been widely adopted conventionally, which has features such as a simple molding process and stable quality of the synthetic resin foam sheet.

In this extrusion foam molding method, a resin composition melt-kneaded with a foaming agent or the like is discharged into the atmosphere from an annular die orifice to form a tubular resin foam, and then the tubular foam body is formed. The synthetic resin foam sheet is manufactured by bringing the surface into contact with a cooling drum to cool, and then cutting open one end of the tubular foam.

In order to improve the appearance and strength such as surface properties and luster, the obtained polystyrene resin foam sheet is so-called extrusion laminate in which heat-melted synthetic resin is laminated, or heat-melted, if necessary. After the surface of the polystyrene-based resin foam sheet is made up by sand lamination, which uses synthetic resin instead of an adhesive and by laminating synthetic resin films, or by thermocompression bonding the film directly to the polystyrene-based resin foam sheet, It is used as a laminated sheet for molding.

The polystyrene resin foam sheet laminate thus supplied is processed into a container such as a bowl by thermoforming, and then, if necessary, on the outer side surface of the container for the purpose of imparting a design property. Curved surface printing of patterns and characters is performed. At this time, if the printability is inferior, print omissions and the like occur, so that the appearance is poor and the product image is deteriorated.

[0006]

SUMMARY OF THE INVENTION It is, therefore, a first object of the present invention to provide a polystyrene resin foam sheet laminate capable of obtaining a container having an excellent appearance by thermoforming. A second object of the present invention is to provide a polystyrene-based resin foam sheet laminate which has good printability when curved surface printing is performed when the container is processed by thermoforming.

[0007]

The above-mentioned various objects of the present invention are achieved by laminating a synthetic resin on at least one side of a polystyrene resin foam sheet, having a basis weight of 50 to 600 g / m ² and a density of 0.10 to 0. A laminated body of 0.25 g / cm ³ and having a compression deformation amount of 0.5 mm or less when a pressure of 4 kg / cm ² is applied in the thickness direction after secondary foaming so that the density becomes the minimum. And a center line average roughness of the surface on which the curved surface is printed is 15 μm or less.

The details of the present invention will be described below. The polystyrene-based resin foamed sheet has a residual amount of the foaming agent added at the time of manufacturing, and therefore has a phenomenon of further foaming when heated, and this phenomenon is called secondary foaming. Further, the polystyrene resin foam sheet, if necessary,
A synthetic resin is laminated on one side or both sides to form a laminated sheet, and then the laminated sheet is softened by heating to secondary-foam the foamed sheet, and then is pressed by a convex mold and a concave mold. Molded. The laminated sheet is preferably manufactured by the extrusion laminating method or the sand laminating method described above.

Further, since the curved surface printing is performed on the outer side surface of the molded container as necessary, if the printability in this case is insufficient, the printing may be omitted and the product image is deteriorated. become. In the present invention, in order to improve the printability described above, in the sheet after secondary foaming of the polystyrene-based resin foam sheet laminate, 4 kg / c in the thickness direction.
The amount of compressive deformation when a pressure of m ² is applied must be 0.5 mm or less, and the center line average of the surfaces corresponding to the surfaces to be subjected to curved surface printing when thermoformed into a container or the like. It is necessary that the roughness is 15 μm or less.

The amount of compressive deformation in the sheet thickness direction is 0.
If it exceeds 5 mm, it is soft when molded into a container, and the printing pressure during curved surface printing is low, and the transferability of the ink is insufficient, resulting in printing defects such as fading and insufficient density. The measurement of the amount of compressive deformation in the present invention uses a sample obtained by cutting the sheet after secondary foaming into 1.5 cm × 1.5 cm, using a circular probe having an area of 1 cm ² at a speed of 0.02 cm / sec. The sample is compressed in the thickness direction from the laminated surface, and the deformation amount (mm) of the thickness when the load becomes 4 kg is the compression deformation amount.
The smaller the amount of compressive deformation, the better the curved surface printability in the case of molding into a container. Moreover, the measuring device may be a commonly used one, and a specific example thereof is a handy compression tester KES manufactured by Kato Tech Co., Ltd.
-G5 and the like.

On the other hand, when the center line average roughness exceeds 15 μm, the unevenness of the surface is large, so that the contact of the printing portion is insufficient when the curved surface printing is performed, and the printing omission easily occurs. In addition, the center line average roughness of the surface in the present invention can be measured according to JIS-B0601 using a surface roughness meter, and the smaller the value, the more the molded container is formed. Good curved surface printing. The measuring device may be a commonly used measuring device, and specific examples thereof include Universal Surface Profile Measuring Device SE-3C manufactured by Kosaka Laboratory Ltd. and the like.

Regarding the basis weight of the polystyrene-based resin foam sheet laminate before secondary foaming, if the basis weight is less than 50 g / m ² , the strength of the molded article becomes too weak, and if it exceeds 600 g / m ² , thermoforming is performed. 50 to 6 because the processing suitability of
It is necessary to be 00 g / m ² . Similarly, the density of the polystyrene-based resin foam sheet laminate before the secondary foaming is
If it exceeds 0.25 g / cm ³ , the heat insulation and strength of the molded article will decrease, and if it is less than 0.10 g / cm ³ , the strength of the molded article will decrease and the sheet surface will become rough.
It is necessary to be 0.25 g / cm ³ .

The polystyrene resin used in the present invention and the raw material used therefor are not particularly limited, but the resin used as an adhesive during sand lamination and the resin film to be laminated are preferably polystyrene resins. In particular, impact-resistant polystyrene resin is preferable. This is because, since the foamed sheet is a polystyrene-based resin, if the resin to be laminated is also polystyrene, the physical properties of the laminated sheet, the laminating processability and the like are well balanced.

The thickness of the resin laminated by extrusion lamination in the laminate used in the present invention, or
The total thickness of the resin as an adhesive and the thickness of the film laminated by sand laminating is 20 to 20.
It is preferably 250 μm. The thickness is 20 μm
If it is less than 250 μm, it is difficult to laminate it to a polystyrene resin foam sheet, and if it exceeds 250 μm, not only the cost becomes high, but also the moldability is deteriorated and the balance as a polystyrene resin product is deteriorated.

The amount of compressive deformation and surface roughness in the sheet thickness direction after secondary foaming of the polystyrene-based resin foamed sheet laminate defined in the present invention is the polystyrene constituting the polystyrene-based resin foamed sheet laminate. It can be controlled by appropriately adjusting the properties of the resin foam sheet and the laminate layer. The properties of the polystyrene resin foamed sheet are preferably controlled by adjusting the amount of the foaming agent added during the production, the amount of the foam nucleating agent, the resin temperature, the cooling conditions of the sheet, and the like.

For example, by reducing the addition amount of the foaming agent at the time of manufacturing, the amount of compressive deformation in the sheet thickness direction after secondary foaming of the laminated polystyrene resin foam sheet laminate is reduced, and the surface roughness is reduced. be able to.
Incidentally, the control of the properties of the polystyrene-based resin foam sheet is possible other than the adjustment of the production conditions described above,
There is no particular limitation.

The control by the laminating layer is performed by appropriately selecting the kind of synthetic resin to be laminated and the film thickness. For example, by increasing the film thickness of the synthetic resin laminated on the polystyrene resin foam sheet, the amount of compressive deformation in the sheet thickness direction after secondary foaming of the polystyrene resin foam sheet laminate is reduced,
The surface roughness can be reduced. 2 in the present invention
The subsequent foaming is performed by appropriately setting the heating temperature and the heating time so that the density of the polystyrene-based resin foam sheet laminate becomes the lowest.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The polystyrene resin foam sheet laminate of the present invention has a basis weight of 50 to 50 obtained by laminating a synthetic resin film on at least one side of a polystyrene resin foam sheet.
600 g / m ² and density of 0.10 to 0.25 g / cm ³
It is a laminated body that has 2
The sheet after the next foaming is 4 kg / cm ^{2 in the} thickness direction.
The amount and type of polystyrene resin used so that the amount of compressive deformation when applying the pressure is 0.5 mm or less, and the centerline average roughness of the surface on which the curved surface is printed is 15 μm or less. , Foaming conditions, cooling conditions, and the type and thickness of the synthetic resin film to be laminated are selected.

[0019]

EFFECTS OF THE INVENTION The polystyrene resin foam sheet laminate of the present invention is suitable in the amount of compressive deformation in the thickness direction and the surface roughness of the surface on which curved surface printing is applied in the sheet after secondary foaming. When performing curved surface printing on a container such as a thermoformed bowl, it is possible to perform good printing without printing omission, and it is suitable for producing a container having a high commercial value.

[0020]

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited thereto. Embodiment 1 FIG. 100 parts by weight of polystyrene resin (heat distortion temperature according to JIS K-6871 is 86 ° C.) was mixed with 0.5 parts by weight of talc, which is a foam nucleating agent, and then heated to 200 ° C. and put into an extruder having a diameter φ of 40 mm. It was charged and melt-kneaded. Then, 5 parts by weight of butane gas as a foaming agent was press-mixed through an injection port provided in the middle of the extruder, and then the mixture was passed through an extruder equipped with an oil circulation type cooling mechanism to pass the polystyrene resin composition at 130 ° C. It is cooled to 15 mm and is attached to the tip of the extruder.
It was discharged from an annular die orifice having a lip opening of 0.45 mm at 0 mm to form a tubular foam.

Next, the tubular foam was blown up at a take-up speed of 3.0 m / min while blowing 0.4 m ³ / min of air at 20 ° C. to cool the surface, and a cooling drum having a diameter φ of 400 mm. After further cooling and solidification by means of cutting, it is cut open and has a thickness of 2.0 mm and a basis weight of 200 g / m ^2.
A polystyrene foam sheet was produced.

On one side of the obtained polystyrene foam sheet, 1 m of high-impact polystyrene resin melted by heat was applied.
Extruded and laminated so that 100 g per ²
A polystyrene foam sheet laminate having a basis weight of 300 g / m ² and a density of 0.14 g / cm ³ was obtained. The obtained polystyrene foam sheet laminate was heated for 90 seconds in an atmosphere of 130 ° C. for secondary foaming, and then 4 kg / cm in the thickness direction.
When the amount of compressive deformation when the pressure of ² is applied, and the center line average roughness on the same surface (laminated surface) as the surface to which curved surface printing is applied when thermoformed into a container, etc.,
The amount of compressive deformation was 0.30 mm, and the center line average roughness of the sheet surface was 10 μm.

Using a continuous molding machine, the obtained resin foam sheet was processed into a bowl having a diameter of 145 mm and a depth of 70 mm so that the laminated surface was on the outside of the bowl. Then
When curved surface printing was applied to the outer side surface of the obtained bowl, a bowl with a good appearance was obtained without missing the printing. The evaluation results of the obtained bowls are as shown in Table 1.

[Table 1]

Embodiment 2 FIG. The thickness was 1.9 mm and the basis weight was 20 mm in exactly the same manner as in Example 1 except that the blowing amount of surface cooling air during blow-up was changed to 0.6 m ³ / min.
A polystyrene foam sheet of 0 g / m ² was prepared. On one side of this polystyrene foam sheet, a hot-melted high-impact polystyrene resin was extruded and laminated so as to be 100 g per 1 m ² . The basis weight of the obtained laminate was 300 g / m ² , and the apparent density was 0.15.
g / cm ³ .

The polystyrene foam sheet laminate thus obtained was heated in an atmosphere of 130 ° C. for 90 seconds for secondary foaming, and then in the same manner as in Example 1, 4 kg in the thickness direction.
When the amount of compressive deformation when a pressure of / cm ² is applied and the center line average roughness on the same surface (laminated surface) as the surface to which curved surface printing is applied when thermoformed in a container or the like are measured, The amount of compressive deformation was 0.18 mm, and the center line average roughness of the sheet surface was 6 μm. When a bowl was thermoformed and printed using a continuous molding machine in exactly the same manner as in Example 1, the same results as in Example 1 were obtained.
The evaluation results are as shown in Table 1.

Embodiment 3 FIG. Except for changing the cooling temperature of the polystyrene resin composition to 135 ° C. in an extruder equipped with an oil circulation type cooling mechanism, the thickness was 2 mm and the basis weight was 200 g / m ^{2 in} exactly the same manner as in Example 1. The polystyrene foam sheet of was produced. To obtain a laminate of polystyrene foam heat melted high impact polystyrene resin extrusion laminated so as to be 1 m ² per 100g on one side of a sheet, the apparent density basis weight at 300 g / m ² is 0.14 g / cm ³ It was

The polystyrene foam sheet laminate thus obtained was subjected to secondary foaming in exactly the same manner as in Example 1, and then the amount of compressive deformation when a pressure of 4 kg / cm ² was applied in the thickness direction,
And, when the center line average roughness on the same surface (laminated surface) as the surface on which curved surface printing is performed when thermoformed into a container or the like is measured, the amount of compressive deformation is 0.43 mm,
The center line average roughness of the sheet surface was 13 μm. When a bowl was thermoformed and printed using a continuous molding machine in exactly the same manner as in Example 1, the same results as in Example 1 were obtained. The evaluation results are as shown in Table 1.

Comparative Example 1 The thickness was 1.8 m in the same manner as in Example 1 except that the addition amount of talc was changed to 0.3 part.
A polystyrene foam sheet having a m and a basis weight of 200 g / m ² was produced. The high-impact polystyrene resin heat-melted on one side of this polystyrene foam sheet is 1 per 1 m ^2.
Extruded and laminated so that the weight becomes 00g, and the basis weight is 30
At 0 g / m ² , a laminate having an apparent density of 0.16 g / cm ³ was obtained.

The obtained polystyrene foam sheet laminate was subjected to secondary foaming in exactly the same manner as in Example 1, and then the deformation amount when a pressure of 4 kg / cm ² was applied in the thickness direction, and to the container etc. When the center line average roughness on the same surface (laminated surface) as the surface on which curved surface printing is applied when thermoformed is measured, the amount of compressive deformation is 0.25 mm, and the center line average roughness of the sheet surface is It was 17 μm.

Using a continuous molding machine, the resin foam sheet was processed into a bowl having a diameter of 145 mm and a depth of 70 mm, with the laminated surface of the resin foam sheet facing outward.
When curved surface printing was applied to the outer side surface of the bowl, it was confirmed that the printing was missing and faint, and the appearance was inferior. The evaluation results are as shown in Table 1.

Comparative Example 2 The thickness was 2. as in Example 1 except that the amount of butane gas added was changed to 6.1 parts.
A polystyrene foam sheet having a size of 3 mm and a basis weight of 200 g / m ² was produced. On one side of this polystyrene foam sheet, heat-melted high-impact polystyrene resin was extruded and laminated so that 100 g per 1 m ² was obtained, and a laminate having a basis weight of 300 g / m ² and an apparent density of 0.13 g / cm ³ was obtained. It was

The polystyrene foam sheet laminate thus obtained was subjected to secondary foaming in exactly the same manner as in Example 1, and then the deformation amount when a pressure of 4 kg / cm ² was applied in the thickness direction,
Also, when the center line average roughness on the same surface (laminated surface) as the surface on which curved surface printing is applied when thermoformed into a container or the like is measured, the compression deformation amount is 0.63 mm, and the center of the sheet surface is measured. The line average roughness was 12 μm.

Using a continuous molding machine, this resin foam sheet was processed into a bowl having a diameter of 145 mm and a depth of 70 mm so that the laminated surface of the resin foam sheet was on the outside, and the curved surface was printed on the outside side surface of the bowl. As a result, it was confirmed that the print density was insufficient and the print was faint, and the appearance was inferior. The evaluation results are as shown in Table 1.

Comparative Example 3. In exactly the same manner as in Example 1, a polystyrene foam sheet having a thickness of 2 mm and a basis weight of 200 g / m ² was produced. 1 m ^{2 of} high-impact polystyrene resin heat-melted on one side of this polystyrene foam sheet
Extruded and laminated so that the weight per unit is 60 g, the basis weight is 260 g / m ² , and the apparent density is 0.13 g / cm ^3.
Was obtained.

The polystyrene foam sheet laminate thus obtained was heated in an atmosphere of 130 ° C. for 90 seconds for secondary foaming, and then the amount of compressive deformation when a pressure of 4 kg / cm ² was applied in the thickness direction, and When the center line average roughness on the same surface (laminated surface) as the surface on which curved surface printing is applied when thermoformed in a container or the like is measured, the amount of compressive deformation is 0.55 mm.
And the center line average roughness of the sheet surface was 17 μm.

Using a continuous molding machine, this resin foam sheet was processed into a bowl with a caliber of 145 mm and a depth of 70 mm so that the laminated surface of the resin foam sheet was on the outside, and the curved surface was printed on the outside surface of the bowl. As a result, it was confirmed that the print density was insufficient and missing, and the appearance was remarkably inferior.
The evaluation results are as shown in Table 1. The above results demonstrate that the polystyrene resin foam sheet laminate of the present invention is suitable for producing a container having curved surface printability.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akito Ogino 1-30-6 Kamiochiai, Shinjuku-ku, Tokyo Inside Nippon Paper Industries Co., Ltd. Product Development Laboratory

Claims (3)

[Claims] 1. A polystyrene resin foam sheet having a synthetic resin laminated on at least one surface thereof, and having a basis weight of 50 to 600 g.
/ M ² and a density of 0.10 to 0.25 g / cm ³ and after secondary foaming so that the density becomes the minimum, a pressure of 4 kg / cm ² is applied in the thickness direction. A polystyrene-based resin foam sheet laminate, which has a compression deformation amount of 0.5 mm or less and a centerline average roughness of a surface on which a curved surface is printed of 15 μm or less. 2. The polystyrene resin foam sheet laminate according to claim 1, wherein the synthetic resin to be laminated is a polystyrene resin. 3. The synthetic resin to be laminated has a thickness of 20 to 250.
The polystyrene-based resin foam sheet laminate according to claim 1 or 2, having a thickness of μm.