JP3448759B2 - Thermoplastic resin laminated foam sheet and container thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin laminated foam sheet and a container comprising a thermoformable thermoplastic resin film and a polystyrene-based resin foam sheet, and more particularly to the depth of a container for containing a cup or instant noodles. TECHNICAL FIELD The present invention relates to a deep container and a thermoplastic resin laminated foam sheet for molding the container.

[0002]

2. Description of the Related Art Conventionally, a deep drawing ratio obtained by dividing the depth of a container by the inner size of the opening of the container is 1. It is difficult to obtain a container larger than 0 by molding a polystyrene-based resin laminated foam sheet, and as one means for solving this, increasing the weight per unit area of the foam sheet has been performed. However, in this method, the weight per container is increased, which increases the cost. Furthermore, since the thickness of the container is regulated, a low-foamed sheet is formed, and the heat insulation performance is deteriorated.

Further, in JP-A-6-335988, in order to mold such a deep-drawn molded product, a foamed sheet laminated with a thermoplastic resin film is used, and a unit area before heating is used. It is proposed that the area must be increased by about 1 to 11%. However, there is a problem in that the container side becomes thin and the strength becomes weak depending on the composition of the material and basis weight of the film and foam obtained by this method to obtain a molded product having a deep drawing ratio of 1.0 or more.

In Japanese Patent Publication No. 63-20702, an average number of cells in the thickness direction of 25 to 400 cells / m ² and a residual foaming agent amount of 0.5% by weight or more are specified to obtain a molded article. Has been proposed. However, identification such as specifying the average number of bubbles and residual foaming agent is not sufficient to obtain a deep-bottomed container, and there are problems in moldability and distribution of the wall thickness of the container, such as cup strength. There is a problem in the physical properties of the container (a part of the side surface of the container is soft, the strength when holding it by hand is weak, it also deforms when hot water is put, and when it is held by holding hot water) The taking efficiency (the opening area of the upper part of the molded product × the number of molded products taken / the molded area) was about 40% or less, and the deep drawing ratio was 1. Items of 0 or more could not be molded at all.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above problems and provides a laminated foam sheet which has a strong side wall and is capable of economically forming a deep drawing container. As a result of intensive research, the present inventors have found that it is important to minimize the strain of the foamed sheet during molding in order to mold a deep-drawing container, and have completed the invention. That is, when extrusion-foaming a polystyrene foam sheet, by controlling the stretching between the slit and the plug of the cylindrical mold, MD (extrusion direction of the foam sheet) and TD (foaming) of the foam sheet at the time of molding are controlled. Distortion of the foamed sheet is suppressed to the extent that it does not adhere to the molding die etc. before molding by making the distortion in both directions (direction perpendicular to the sheet extrusion direction) as small as possible and in good balance, by heating with a heater during molding. Has found that is important.

[0006]

This onset bright [Means for solving problems], a laminated sheet of a thermoplastic resin film and the polystyrene-based resin foam sheet, after heating of a deformation by heating for molding MD length / TD The length after heating is 0.90 to l. 1
0, and the heating deformation ratio obtained by dividing the length after heating for molding as described above by the length before heating for molding is 0.95 to 1% for both MD and TD. It is a thermoplastic resin laminate foam sheet you wherein is 10, the deformation by heating for molding, the length after heating length / TD after heating the MD is zero.
97-1. No. 05 and the heating deformation ratio obtained by dividing the length after heating for the above-mentioned molding by the length before heating for molding is 0.97 to 1 for both MD and TD. It is preferably 08.
The present invention also relates to a container obtained by thermoforming the thermoplastic resin laminated foam sheet as described above, and in particular, the deep drawing ratio obtained by dividing the depth of the container by the inner size of the opening of the container is 1.0 to 1.8. The container is preferable as a container for cups, instant noodles and the like.

In the present invention, examples of the polystyrene resin used for the polystyrene resin foam sheet include styrene, methylstyrene, ethylstyrene, isopropylstyrene, dimethylstyrene. Homopolymers or copolymers of paramethylstyrene, chlorostyrene, bromostyrene, vinyltoluene, vinylxylene, for example, as a resin, styrene-maleic anhydride copolymer, styrene-acrylic acid copolymer, styrene-acrylonitrile resin ,
Acrylonitrile-butadiene-styrene resin may be mentioned. When heat resistance is required, a heat resistant polystyrene resin can be used, and for example, a styrene copolymer containing acrylic acid, methacrylic acid, acrylonitrile, and maleic anhydride in an amount of 3 to 15% by weight is preferable.

The polystyrene resin used in the present invention may be further mixed with a rubber such as butadiene rubber, elastomer, ethylene propylene rubber, ethylene butadiene rubber, isoprene, chloroprene or a copolymer of butadiene and styrene. The mixing amount is preferably about 0.05 to 15% by weight. The reason for this is that if it is less than 0.05% by weight, it may crack during handling depending on the combination with the thermoplastic resin film to be laminated, and if it exceeds 15% by weight, insufficient strength may occur and the size of the cup, This is because the printability may deteriorate depending on the shape. Further, by mixing the above-mentioned rubber component with polystyrene resin, and further by mixing 0.1 to 40% by weight of polyolefin resin such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, etc., heat resistance is obtained. You can get better. However, when strength is required, it is necessary to control the rubber content to 5% by weight or less.

A foaming agent or the like is added to the polystyrene resin, and extrusion foam molding is performed to obtain a foam sheet. At this time, 0.5 to 15% by weight of the filler is added to remove the mold.
The appearance and heat resistance of the surface can be improved. Examples of such fillers include talc, calcium carbonate, shirasu, gypsum, carbon black, white carbon, magnesium carbonate, clay, general inorganic fillers such as natural silicic acid and metal powder, which are charged into an extruder. It may be used as a master batch before use. Further, as a compounding agent, for example, a cell regulator, a pigment or the like may be added.

As the foaming agent usable in the present invention, various volatile foaming agents, decomposable foaming agents and the like can be used. The volatile blowing agent, a hydrocarbon, propane, i- butane, n- butane, i- pentane, n- pentane or a mixture thereof, _{and, N 2, CO 2, N} 2 / CO 2, water, water And -O
_{H, -COOH, -CN, -NH 3} , -OSO 3 H, -N
_{H, CO, NH 2, -CONH} 2, -COOR, -CHS
Examples thereof include a mixture with a group having O ₃ H, —SO ₃ H, —COON ₄ , and —COONH ₄ , and the like. Further, examples of the decomposing type foaming agent include foaming agents such as azodicarboxylic acid amide, dinitropentamethylenetetramine, and 4,4′oxybis (benzenesulfonylhydrazide). Furthermore, a combination of an organic acid such as sodium bicarbonate or citric acid or a salt thereof with a bicarbonate can be used. In addition, for example, a combination of an organic acid such as sodium bicarbonate citric acid or a salt thereof and bicarbonate can be used, and these can also be used by coating with a low molecular weight olefin, liquid paraffin, tallow oil, etc. . In addition, it is also possible to use a mixture thereof, and two or more kinds thereof may be mixed. All of these are also available as a masterbatch with powder, flakes, or a thermoplastic resin.

The expansion ratio of the polystyrene resin foam sheet of the present invention is about 1.2 to 15 times. It is preferably 1.3 to 10 times. The thickness of the polystyrene-based resin foam sheet is appropriately selected depending on the wall thickness of the tray or container of this type. Usually about 0.3-5.0 mm,
Preferably, it is about 0.5 to 3.0 mm.

In the present invention, the above-mentioned polystyrene resin can be used for the thermoplastic resin film laminated on the polystyrene resin foam sheet. In addition, a mixed resin of polystyrene-based resin and high-impact polystyrene, or high-impact polystyrene may be a styrene-butadiene block copolymer in which the copolymer is dispersed in a salami structure. . The styrene-butadiene block copolymer preferably has a large particle diameter of 0.3 to 10 μm. Other resins that can be used for the thermoplastic resin film include linear low density polyethylene, high density polyethylene, low density polyethylene, polypropylene, ethylene / propylene random polymer, ethylene / propylene block polymer, ethylene / propylene butene copolymer, ethylene- Vinyl acetate copolymer, ethylene-unsaturated carboxylic acid ester copolymer (for example, ethylene-
Methyl methacrylate copolymer), engineered ethylene-unsaturated carboxylic acid metal salt copolymer (for example, ethylene-magnesium (or zinc) acrylate copolymer), propylene-
Unsaturated carboxylic acid of vinyl chloride copolymer, propylene-butene copolymer, propylene-maleic anhydride copolymer, propylene-olefin copolymer (propylene-ethylene copolymer, propylene-butene-1 copolymer) polyethylene or polypropylene (for example, Maleic anhydride) modified products, ethylene-propylene rubber, atactic polypropylene and the like are mentioned, and polyethylene, ethylene-propylene copolymer, propylene-butene-1.
Examples thereof include copolymers and mixtures of two or more of these, and films of polyethylene terephthalate, polybutylene terephthalate, and the like. The polypropylene resin film may be unstretched, uniaxially stretched, or biaxially stretched, but is particularly preferable when an unstretched film is used because of good moldability.

Silicone oil may be mixed in the thermoplastic resin film in an amount of 0.01 to 3% by weight. If the silicone oil content is 0.01% by weight or less, the effect of improving the mold release property and blocking prevention when the container is molded cannot be expected so much.
In addition, the slippage between the container and the blanket of the printing machine becomes poor, and the printability also deteriorates. On the other hand, if the content is 3% by weight or more, the extrusion stability during film production is deteriorated and the appearance of the film is also deteriorated, which is not preferable. When the silicone oil is kneaded into the thermoplastic film, up to about 0.2% by weight can be kneaded into the resin as a blend, and above this amount, the resin slips and cannot be stably eaten into the screw. Therefore, in order to mix over 0.2% by weight to 3% by weight,
It may be carried out by a so-called injection method in which it is kneaded into a resin with a mixing roll such as a calender roll to form pellets, added during the polymerization or pelletization after the polymerization, or pressed into the extruder. preferable.

Silicon oil is added in an amount of 0.01% by weight to 0.
After kneading into 2% by weight resin and, if further effect is required, after kneading into 0.01% by weight to 0.2% by weight resin, apply even silicone oil on the film without uneven application. Therefore, when the resin is kneaded into 0.01% to 0.2% by weight of resin and further coated with silicone oil, printing unevenness does not occur. Further, an antistatic material such as stearic acid monoglyceride can be kneaded at the same time with the silicone oil. Further, silicone oil may be mixed with the polystyrene resin foam sheet, so that the foamability and the like can be improved. In addition, printing may be performed on a thermoplastic resin film in which silicon is kneaded, and then the printed surface or the unprinted surface may be attached to a polystyrene resin foam sheet. In addition, if the thermoplastic resin film is mixed with 0.1 to 3.0% by weight of a white filler such as titanium white or calcium carbonate, the printability is improved.

As a method for laminating a polystyrene-based resin foam sheet and a thermoplastic resin film, a film provided with an adhesive layer is often adhered to the foam sheet.
In this case, ethylene-vinyl acetate copolymer, ethylene-
Partial saponification of vinyl acetate copolymer, chlorinated polyethylene, layer formed by extrusion laminating chlorinated polypropylene, etc., polybutadiene, polyisoprene, styrene-butadiene copolymer,
A layer formed by extrusion laminating a mixture of a styrene-isoprene copolymer or the like with a polyolefin resin such as polypropylene or polyethylene is used as an adhesive layer. Further, the adhesive layer, polyvinyl acetate, polyvinyl chloride, vinyl resin such as polyvinylidene chloride, cellulose resin such as nitrocellulose, ethyl cellulose, cellulose acetate, epoxy resin, acrylonitrile-butadiene copolymer, etc., It can also be obtained as a dry laminate formed by applying an adhesive dissolved in an organic solvent to a thermoplastic resin film and then drying it.

As another method, when a thermoplastic resin film is laminated on a sheet-like foam in a die, a confluent die (for example, a crosshead die) may be used, and the die slit may be placed in front of the die slit. Inflow may be performed for stacking. When laminating the foamed sheet after extrusion foaming, a thermoplastic resin film extruder may be combined with a take-up machine to extrude the film to continuously laminate the thermoplastic resin film. It may be performed by appropriately laminating a resin film on the sheet-shaped foam.

When used as a food container, a polystyrene resin foam sheet, a barrier film, and a thermoplastic resin film, which are previously laminated with a barrier film in order to prolong the shelf life of the contents. A laminated foam sheet obtained by laminating is used. As the barrier film, specifically, ethylene / vinyl acetate copolymer, polyvinyl alcohol, polyvinylidene chloride, polyamide, polyester, polyacrylonitrile, vinylidene chloride / acrylonitrile copolymer, acrylonitrile methyl methacrylate / Butadiene copolymer, nylon 6, biaxially oriented nylon, biaxially oriented polyethylene terephthalate, biaxially oriented polypropylene.
Examples thereof include high-density polyethylene, ionomer resin (for example, Surlyn (registered trademark)), or metal vapor-deposited films, or a laminate of these films.

In the present invention, when the polystyrene resin foam sheet and the barrier film are laminated,
In addition to extrusion, there is a method of performing heat lamination, in which the film is heated and pressure-bonded from the side opposite to the joint surface with a heat roll. In this case, it is preferable that the surface of the roll to be heated and pressure-bonded is plated with chrome or coated with Teflon to prevent stickiness with the heated film. In the present invention, it is more preferable that the joint surface is also heated by the heating device together with the thermocompression bonding by the hot roll.

By laminating the above thermoplastic resin film, a thermoplastic resin laminated foamed sheet suitable for forming a deep drawing container having strength can be obtained. The thermoplastic resin film is
It is suitable to use the one having a thickness of 5 to 600 μm. In some cases, thermoplastic resin films may be laminated on both sides. If the thickness of the film is less than 5 μm, the elongation at the time of molding will be poor, and the mechanical strength of the obtained molded product will be low and it will be inappropriate. On the other hand, if it exceeds 600 μm, when punching after molding, air bubbles in the lip portion are easily crushed and communication is caused, and a problem that the film and the foamed sheet are peeled off easily occurs, which is disadvantageous from the economical point of view. So not suitable. A more preferable thickness of the thermoplastic resin film is 30 to 500 μm.

The laminated foam sheet of the present invention has a length after heating of MD / a length after heating of TD, which is a deformation due to heating for molding, of 0.90 to 1%. It is necessary that the heating deformation ratio is 10 and the heating deformation ratio obtained by dividing the length after heating for molding by the length before heating for molding is 0.95 to 1.10. Further, preferably, the length of MD after heating / the length of TD after heating is 0.97 to l. 05 and the heating deformation ratio obtained by dividing the length after heating for molding by the length before heating for molding is 0.97 to 1.
It is 08. In the present invention, heating for molding is actually
Depending on the temperature and time when molding the laminated foam sheet with a molding machine
is there. These figures are the thermoplastic resin laminated foam of the present invention.
The front and back sides of the sheet must be filled
It

The thermoplastic resin laminated foam sheet of the present invention as described above has a blow-up ratio, which is the ratio of the plug diameter divided by the die slit diameter, in extrusion foam molding using a cylindrical die. 1.8 to 3.5, the gap between the mold slits is 0.25 to 1.2 mm, and the extruder temperature is 150 to 2
The temperature of the molten resin near the mold outlet is set to 65 ° C.
It can be obtained at 185 ° C. The extrusion rate varies depending on the extruder used, but in general, it may be appropriately set at 75 to 400 kg / H depending on the extruder used. Furthermore, after extruding from a cylindrical mold and foam-molding into an annular sheet shape, it is cooled by air. At this time, the cooling air amount is about 0.04 to 0.3 m ³ / m ² , and the temperature is about 1
It is preferable to perform it within 5 seconds immediately after extrusion at 0 ° C to 80 ° C. In particular, the blow-up ratio should be between 2/5 and 3/5 of the expansion ratio, and the extrusion amount should be such that the island pattern in the extrusion direction of the foam sheet disappears within 1/3 of the distance from the mold slit to the plug. It is better to adjust the take-up speed and cooling conditions. The foam shape of the central part 2/3 of the thickness of this foam sheet is 0.9 ≦ TD / VD ≦ 1.5, 0.9 ≦ MD / V
D ≦ 1.1 and TD / VD ≧ MD / VD. However, in this formula, the bubble diameters are MD, TD, and VD (thickness direction).

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Production examples of the thermoplastic resin laminated foam sheet of the present invention, representative physical properties of the sheet, and evaluation of moldability will be described with reference to Examples and Comparative Examples. Examples 1 to 4 A polystyrene resin foam sheet was extrusion-foam molded as follows using a tandem extruder in which extruders having a diameter of 115 mm and a diameter of 150 mm were connected. First, using 100 parts by weight of polystyrene (trade name: HRM-2, manufactured by Denki Kagaku Kogyo Co., Ltd.) in a hopper of an extruder having a diameter of 115 mm, a master batch of 20 parts by weight of talc was used to prepare talc of 0.3-2. After adding and mixing so as to be in parts by weight and mixing and melting while heating at 150 ° C to 265 ° C in an extruder, a foaming agent having a normal butane / isobutane ratio of 7/3 is polystyrene. 1.0 to 3.0% by weight is injected, mixed, and then introduced into an extruder having a connected diameter of 150 mm, and the temperature is 10 to 15 ° C. lower than that of a conventional polystyrene resin foam sheet. It is cooled to about 140 to 110 ° C. and then a cylindrical mold (slit aperture 160 to 340 mm, slit interval 0.
(3 to 0.6 mm), cooled and molded with an inner cylindrical plug, and then cut at two places to obtain a width of about 1000
A polystyrene foam sheet of mm was obtained. Immediately after the extrusion, the foamed sheet was cooled. The cooling air amount was 0.05 to 0.25 m ³ / m ² , and the air temperature was 20 to.
The temperature was adjusted to 70 ° C.

Further, using an extruder having a diameter of 90 mm, 90 parts by weight of high-impact polystyrene (trade name: HlE-4, manufactured by Denki Kagaku Co., Ltd.) was added to the extruder.
10 parts by weight of Tuftec H1014 (manufactured by Asahi Kasei Kogyo Co., Ltd.) as a rubber component were put into a hopper and melted, and then a film having a thickness shown in Table I was extruded using a T-die to obtain a foamed product. The sheet was laminated by lamination. The obtained laminated sheet is formed so that the film side is on the outside, and the opening has a diameter of 110 mm and a depth of 121 m.
m containers were obtained. Table I shows the representative physical properties and moldability evaluation of the obtained laminated sheet. The heating time for molding was 25, 2 in Examples 1, 2, 3, and 4, respectively.
It was set to 1, 21, 28 seconds.

[0024]

[Table 1]

Comparative Examples 1 to 4 In Examples 1 to 4, the composition was introduced into an extruder having a diameter of 150 mm, cooled to about 155 to 129 ° C., and the gap between slits was 0.5 to 0.8 mm. The sheet was manufactured in the same manner except that the cooling air amount of the sheet was 0.05 to 0.15 m ³ / m ² .

EXAMPLE 5 Polystyrene (trade name: G-
13-55, manufactured by Nippon Steel Chemical Co., Ltd.) 0.5 parts by weight of talc was added to 100 parts by weight and mixed, and after mixing and melting, normal butane / isobutane was added to polystyrene as a foaming agent. 2.8% by weight of a foaming agent having a ratio of 6/4 was injected and mixed, and then cooled.
On the other hand, a high-impact polystyrene (trade name: Styron 475D, manufactured by Asahi Kasei Kogyo Co., Ltd.) was put into an extruder having a diameter of 65 mm from a hopper, melted, and then merged with the polystyrene containing the foaming agent to form a slit gap. Has a diameter of 0.6 mm and a slit diameter of 110 mm, and is extruded and foamed at a rate of about 110 kg / hour, the cooling air amount is 0.1 m ³ / m ² , and the cooling air temperature is 50 ° C. After molding by cooling with the plug, the width is 10
A 00 mm laminated sheet was obtained. When the thickness of the film was peeled off and measured, the thickness was 200 μm, the thickness of the foamed sheet was 2.2 mm, and the expansion ratio was 5.2 times. The obtained laminated sheet was molded so that the film side was on the outside to obtain a container having an opening having a diameter of 110 mm and a depth of 121 mm.
The representative physical properties and moldability evaluation of the obtained laminated sheet are shown in Table I.
It was shown to.

Example 6 On the foamed sheet side of the laminated sheet obtained in Example 5, a high impact polystyrene film having a thickness of 25 μm (trade name: D type, manufactured by Towa Kako Co., Ltd.) was laminated using a heat roll. A three-layer laminated sheet was obtained. The 25 μm film side of the obtained laminated sheet was molded so as to be the outside to obtain a container having an opening with a diameter of 110 mm and a depth of 121 mm. Table I shows the representative physical properties and moldability evaluation of the obtained laminated sheet.

Example 7 Polystyrene was used as a styrene-acrylic copolymer (trade name:
G-9001, manufactured by Asahi Kasei Kogyo Co., Ltd.), and the blowing agent is a normal butane / isobutane ratio of 35/65.
A laminated sheet was obtained in the same manner as in Example 1 except that the above was changed. The obtained laminated sheet is formed so that the film side is on the outside, and the opening has a diameter of 110 mm and a depth of 121 m.
m containers were obtained. Table I shows the representative physical properties and moldability evaluation of the obtained laminated sheet.

Example 8 The foamed sheet obtained in Example 1 was used as a barrier film,
A 90 μm-thick Eval-based multilayer film (manufactured by Sumitomo Bakelite Co., Ltd.) was laminated by hot rolls to obtain a laminated sheet. The film side of the obtained laminated sheet is formed to be the outside, and the opening has a diameter of 110 mm,
A container having a depth of 121 mm was obtained. Table I shows the representative physical properties and moldability evaluation of the obtained laminated sheet.

Example 9 A foamed sheet having a thickness of 1.5 mm and a magnification of 6.1 was obtained from the apparatus and raw materials used in Example 1. Example of the foam sheet-
A 70 μm film was laminated with the apparatus and raw material used in 1. The two-layer sheet was molded so that the film side was the outside, and a container having an opening with an inner diameter of 45 mm and a depth of 50 mm was obtained. Table I shows the representative physical properties and moldability evaluation of the obtained laminated sheet.

Example 10 Using an extruder having a diameter of 65 mm, high-impact polystyrene was mixed with ethylene-vinyl acetate copolymer resin (trade name:
V403E, manufactured by Mitsubishi Chemical Co., Ltd.) and extruded in the same manner as in Example 5. The obtained laminated sheet was photographed and measured using an electron microscope. As a result, the thickness of the ethylene-vinyl acetate copolymer resin was 15 μm and the thickness of the foamed sheet was 2.1.
The expansion ratio in mm was 5.0. A high-density polyethylene film (density 0.952,
A thickness of 100 μm) was laminated on the ethylene-vinyl acetate copolymer resin side with a hot roll and laminated to obtain a laminated sheet. As for moldability, the film side of the laminated sheet is formed to be the outside, and the inner diameter of the opening is 45 mm and the depth is 5 mm.
A 0 mm container was obtained. Typical physical properties of the obtained laminated sheet,
And the moldability evaluation is shown in Table I.

Example 11 The foamed sheet obtained in Example 1 (thickness 2.1, magnification 4.7)
(2 times), a urethane adhesive was applied, the solution was completely evaporated, and then a 120 μm polyethylene terephthalate resin film was laminated with a hot roll. The obtained laminated sheet was molded so that the film side was on the outside, and a container having an opening with a diameter of 45 mm and a depth of 50 mm was obtained. Table I shows the representative physical properties and moldability evaluation of the obtained laminated sheet.

Example 12 Polystyrene (trade name: G-
13-55, Nippon Steel Chemical Co., Ltd.) 100 parts by weight, Trade name: Tuftec (Asahi Kasei Co., Ltd.) 5 wt%, polypropylene (Trade name: EA9A, Mitsubishi Chemical Co., Ltd.) 30 wt% , 0.5 parts by weight of talc were added and mixed, and after mixing and melting, normal butane / foaming agent was added to polystyrene as a foaming agent.
2.0% by weight of a blowing agent having an isobutane ratio of 4/6
Was poured, mixed, and then cooled. On the other hand, a high-impact polystyrene (trade name: Styron 475D, manufactured by Asahi Kasei Kogyo Co., Ltd.) was put into an extruder having a diameter of 65 mm from a hopper, melted, and then merged with the polystyrene containing the foaming agent to form a slit gap. Of 0.6 mm and a slit having a diameter of 110 mm is extruded and foamed at a rate of about 100 kg / hour, and the cooling air amount is 0.1 m ³ / m ² .
It was cooled at a temperature of cooling air of 40 ° C., cooled with a cylindrical plug, molded, and cut to obtain a laminated sheet having a width of 1000 mm. When the thickness of the film is peeled off and measured, the thickness is 1
The thickness of the foamed sheet was 80 μm, the thickness was 2.0 mm, and the expansion ratio was 4.5. The obtained laminated sheet was molded so that the film side was on the outside, and a container having an opening with a diameter of 45 mm and a depth of 50 mm was obtained. Table I shows the representative physical properties and moldability evaluation of the obtained laminated sheet.

The representative physical properties and moldability were evaluated by the following methods. (Deformation by heating for molding) A value obtained by dividing the length of MD after heating by the length of TD after heating. The measuring method is M
4 samples of 600 mm in D direction and 600 mm in TD direction
Clamp one side and put side 500 at the center of the clamp.
Draw a square of mm, heat it at the molding temperature for the molding time, remove the clamp, MD at about the center of the square
The length and TD length values were measured.

(Length measured by heating for molding / method for measuring length before molding heating) As described above, M after heating for molding
Measure the length of D and TD, and measure the length before heating to 500
The value is divided by mm.

(Heating Temperature for Molding) The ambient temperature between the heater of the molding machine heating zone and the foamed sheet. (Overheat time) The time period in which the foamed sheet is put into the atmosphere temperature of the heating zone of the molding machine and heated to melt the surface or the thickness starts to decrease, whichever is shorter. (Heating time) It was empirically set to about 80 to 95% with respect to the overheating time at the heating temperature for molding.

(Evaluation of Moldability) In Examples 1 to 8 and Comparative Examples 1 to 4, each laminated foam sheet having a side of 600 mm was clamped on four sides to form 18 containers. The shape of the container is 110 mm inside the opening, and the width of the opening lip is 4 m.
m, the outer diameter of the bottom is 75 mm, and the depth of the container is 121 mm. The deep drawing ratio is 1.1 because it is the depth of the container / the inner size of the container opening. ◯: All molding is good Δ: There are cracks inside the cup or the side wall becomes thin. X: Cannot be molded. Further, in Examples 9 to 12, each laminated foam sheet having a side of 600 mm was clamped on four sides to form 116 containers. The shape of the container is such that the inner diameter of the opening is 45 mm, the width of the opening lip is 3 mm, the outer diameter of the bottom is 30 mm, and the depth of the container is 50 mm.
It has an inverted truncated cone shape of mm. The deep drawing ratio is 1.1 because it is the depth of the container / the inner size of the container opening. Note that the evaluations of moldability ◯ and × were the same as above.

(Strength of Molded Product) Compressive Strength: The molded container is compressed from the bottom at a speed of 400 mm / min using a Tensilon measuring instrument to measure the strength when the container buckles. Lip strength: The strength when compressed by 10 mm from the outside of the opening of the container at a pressing speed of the tensilon measuring device of 400 mm / min is measured.

[0039]

INDUSTRIAL APPLICABILITY The present invention controls the strain remaining in a laminated foam sheet to control the length of deformation MD by heating during molding / the length of TD and the length during heating during heating / the length before heating. By adjusting the deformation in the MD and TD directions, the laminated foam sheet is prevented from sagging during heat molding, and the molding balance is good, so a deep-bottomed container with a deep drawing ratio of 1.0 to 1.8 is molded. can do. Further, the deep-bottomed container formed by the laminated foam sheet of the present invention has a small difference in wall thickness between upper, middle and lower side walls, and a small difference in wall thickness and basis weight around each side wall. Since it is uniform, it can be made stiff.

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Claims (8)

(57) [Claims] 1. A laminated sheet of a thermoplastic resin film and a polystyrene resin foam sheet, wherein MD has a length after heating / TD has a length after heating of 0.90, which is a deformation caused by heating for molding. ~ L. 10 and the heating deformation ratio obtained by dividing the length after heating for molding described above by the length before heating for molding is 0.95 to 1% for both MD and TD. The thermoplastic resin laminate foam sheet you being 10. 2. MD which is deformation by heating for molding
After heating / TD after heating has a length of 0.97-1.
No. 05 and the heating deformation ratio obtained by dividing the length after heating for the above-mentioned molding by the length before heating for molding is 0.97 to 1 for both MD and TD. The thermoplastic resin laminated foam sheet according to claim 1, wherein the thermoplastic resin laminated foam sheet is 08. 3. The thermoplastic resin laminated foam sheet according to claim 1, wherein the polystyrene resin foam sheet is a heat-resistant polystyrene resin foam sheet. 4. The thermoplastic resin laminated foam sheet according to claim 1, wherein the polystyrene-based resin foam sheet contains a rubber component in an amount of 0.05 to 15.0% by weight. 5. The polystyrene-based resin foamed sheet contains a rubber content of 0.05 to 15.0% by weight and a polyolefin-based resin of 0.1 to 40% by weight. The thermoplastic resin laminated foam sheet described. 6. The thermoplastic resin laminated foamed sheet according to claim 1, wherein the thermoplastic resin film is a barrier film or is further laminated with a barrier film. 7. A container obtained by thermoforming the thermoplastic resin laminated foam sheet according to claim 1. 8. The container according to claim 7, wherein the deep drawing ratio obtained by dividing the depth of the container by the inner size of the opening of the container is 1.0 to 1.8.