JPH07148877A - Laminated foamed sheet and container - Google Patents

Abstract

PURPOSE:To enable a separated foamed sheet to be used again by making an aluminum foil easily separable from the foamed sheet egg by a method wherein a cell size of a surface of the foamed sheet on a side of laminating the aluminum foil, and separation strength of the aluminum foil laminated on the foamed sheet are specified. CONSTITUTION:A laminated foamed sheet is formed by laminating an aluminum foil on at least one side of a foamed sheet. There are a foamed polystyrene sheet, a foamed polyester sheet, or a foamed polyolefin sheet, etc., as the foamed sheet. Herein, a cell size of a surface of the foamed sheet is made at most 0.5mm, and the aluminum sheet is thermally laminated so that it can be separated off from the foamed sheet by a force of 5g/25mm width to 310g/25mm width. Since the obtained laminated foamed sheet has a suitable separation strength, it is suitable for a tray for food and its container.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated foam sheet mainly composed of an aluminum foil suitable for use in food trays and the like, and an expanded polystyrene sheet.

[0002]

2. Description of the Related Art Expanded polystyrene, expanded polyester,
A tray or container made of a synthetic resin foamed sheet such as a foamed polyolefin takes advantage of its characteristics and can be used for various food trays such as vegetables, meat or fish, and various foods already prepared or Widely used as a container.

However, recently, after these trays or containers have been used, there is a demand for recovery and reuse. However, the inner surface of these trays or containers is difficult to clean, and, for example, when a tray containing cooked food is discarded with the food left behind, it is extremely unsanitary and sometimes produces an offensive odor. Also, for example, when storing foods such as raw noodles and ham, in order to prolong the shelf life of the contents, a film different from the foamed sheet is attached to the inner surface of the tray for use. ing.

As one of the methods for recovering these trays, it is considered that instead of cleaning the inner surface of the tray, a polyolefin film is attached, and after use, the polyolefin film is peeled off and the tray is reused. (Actual Kaihei 4-
38942 gazette). However, regarding the collection and reuse of trays with different types of films attached,
No good method has been proposed yet. In particular, when reusing a recovered product after use, a method of sticking a thermoplastic film or a barrier film is conceivable, assuming that impurities and additives of the recovered tray remain in the tray. As a more complete method, aluminum foil is the best, and there are various problems in collecting trays having such aluminum foil attached.

Conventionally, as a method of sticking a film to a tray main body, a film forming polymer solution is applied to the inner surface of the tray to form a coating layer, or an inner surface film is stuck with an adhesive. However, the film obtained by these methods does not have stable adhesiveness, and in some cases it is cut during peeling because the film is weak, or when it is in use when the adhesive strength is weak. It peels off, and further,
When the adhesive strength is large, there are various problems such as that the adhesive cannot be peeled off even after use. The same problem occurred when aluminum foil was attached instead of these films.

[0006]

The present inventor has improved the above-mentioned drawbacks and can easily form a foam sheet without breaking the aluminum foil.
As a result of various studies on a laminated foam sheet that can be peeled from the sheet and can be reused, the present invention has been completed. The object of the present invention is to easily peel the aluminum foil without tearing it from the foam sheet. The foamed sheet provides a laminated foamed sheet suitable for a reusable food container and a container made of this sheet.

[0007]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a laminated foam sheet in which an aluminum foil is laminated on at least one side of the foam sheet, and a cell on the surface of the foam sheet on which the aluminum foil is laminated. A laminated foam sheet having a size of 0.5 mm or less, wherein the aluminum foil is laminated so as to be peeled from the foam sheet with a force of 5 g / 25 mm width to 310 g / 25 mm width, and It is preferable that the container is composed of this sheet, and in particular, the foamed sheet is one in which a used recovered product is reused. In the present invention,
As the foamed sheet, a foamed sheet such as a foamed polystyrene sheet (hereinafter also referred to as PSP), a foamed polyester sheet, or a foamed polyolefin sheet.
And the cell size of the surface of the foamed sheet is 0.5 m.
Aluminum foil is 5g / 25mm width ~ 310g / 2 under m
The stability of the adhesive force was able to be ensured and the above-mentioned problems could be solved by giving a specific property that it can be peeled from the foamed sheet with a force of 5 mm width. The container in the present invention mainly stores foods such as trays, and its method and shape are not limited.

In the present invention, the cell size on the surface means
The average number of bubbles (d) was calculated by the following formula by measuring the number of bubbles on a straight line 10 mm on the minor axis side of the bubbles on the surface of the foamed sheet or on the surface from which the film was peeled when laminated. did. d = 10 mm / number of bubbles However, in the case where the entire surface is not filled with bubbles such as a high density product, it is calculated by subtracting the total length without bubbles from 10 mm of the molecule of the formula. In the present invention, the value measured by the above method is 0.5 mm or less, and if it exceeds this value, the adhesiveness will not be stable and will not meet the purpose.

In the present invention, the peel strength between the foam sheet and the aluminum foil is 5 g / 25 mm to 310 g / 2.
The range is 5 mm. That is, since aluminum foil is easy to tear, 3
It is necessary to make the width 10 g / 25 mm or less. 310 g /
If the width exceeds 25 mm, it is necessary to adhere other reinforcing materials (film, cloth, etc.) to the aluminum foil to prevent breakage during peeling. When the peel strength is less than 5 g / 25 mm,
It often peels off during use as a container.

In the method for producing a foamed sheet according to the present invention, first, a polystyrene resin, a polyolefin resin, a polyester resin foamed sheet, etc. are fed into an extruder, heated and kneaded to be melted in a molten state. The resin is produced by adding a foaming agent. The polystyrene-based resin used in the present invention is a polymer having a styrene-based vinyl monomer such as styrene, methylstyrene and dimethylstyrene as a main constituent unit, and styrene is used as the expanded polystyrene-based sheet in the present invention. 50% by weight of system monomer
A foamed sheet composed of a copolymer or a polystyrene homopolymer containing the above, as a monomer copolymerizable with a styrene monomer, acrylic acid, methacrylic acid or their esters, acrylonitrile,
Acrylic acid, methacrylonitrile, maleic anhydride and the like.

As the polyolefin resin, high density polyethylene, low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-carboxylic acid ester copolymer, ethylene-carboxylic acid metal salt copolymer, crystalline propylene homopolymer. -, A crystalline propylene-ethylene copolymer, a crystalline propylene-ethylene-diene terpolymer, and as the polyester resin, polyethylene terephthalate, polybutylene terephthalate, polybutylene terephthalate Elastomer, crystalline polyester, polycyclohexane terephthalate and the like can be mentioned.

Examples of the blowing agent include hydrocarbons such as propane, i-butane, n-butane, i-pentane, n-pentane, or a mixture thereof, and N ₂ , CO ₂ , N.
₂ / CO _2, water, water with -OH, -COOH, -CN, -N
_{H 3, -OSO 3 H, -NH} , CO, NH 2, -CON
_{H 2, -COOR, -CHSO 3 H} , -SO 3 H, -CO
ON _4, a mixture of those with -COONH _4, groups. Further, examples of the organic foaming agent include azodicarboxylic acid amide, dinitropentamethylenetetramine, and 4,4′oxybis (benzenesulfonylhydrazide). Further, a combination of an organic acid such as sodium bicarbonate or citric acid or a salt thereof with a bicarbonate can be used. Alternatively, for example, a combination of an organic acid such as sodium bicarbonate citric acid or a salt thereof with bicarbonate, citric acid esters, etc. can be used,
These can be used after being coated with a low molecular weight olefin, paraffin tallow oil or the like. Others are mixtures of these.

The foaming ratio of the foamed sheet is about 1.5 to 20 times. In forming the foamed sheet, a compounding agent usually used in the resin,
For example, a bubble regulator, a pigment or the like may be added. The thickness of the foamed sheet in the present invention is not particularly specified,
Generally, it may have the thickness of the foamed sheet which constitutes this type of tray.

On the other hand, the thickness of the aluminum foil laminated on the foam sheet is about 10 to 100 μm, and the aluminum foil thickness is 10
If the thickness is less than μm, the aluminum foil alone is easily torn when peeled off and is difficult to separate. In addition, when molding or the like, even if the method for adhering to the foamed sheet is devised, there are observed phenomena such as formation of holes and frequent occurrence of wrinkles. Further, if it exceeds 100 μm, not only the economy but also the heat storage during thermal lamination is large, and the phenomenon that the foam becomes thin due to heat is observed. Therefore, if the thickness exceeds about 60 μm, it is preferable to extrude the adhesive layer to laminate so as to avoid such a phenomenon.
Further, the tray and the container can be molded from the laminated foam sheet up to a thickness of about 60 μm.

In the present invention, an aluminum foil is added to the foam sheet as a binder (ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer and styrene-butadiene (block) copolymer elastomer) and a mixture thereof. )
A laminated foam sheet may be used. When a container is molded using such a foamed sheet, the aluminum foil comes inside the container, so the lid is sealed on the aluminum foil. In this case, the peel strength of the aluminum foil is about 1
If the width is 00 g / 25 mm or less, the aluminum foil may be peeled off when the lid is peeled off to use the container, which is a problem.

In such a case, the lid of the molding die is sealed.
By forming uneven stripes at the positions to be rolled, knurling, pruning, or making grooves along the container ribs in a ring shape, the peel strength can be improved only in the part pressed by the mold press during molding. The problem can be solved by increasing by 20 to 200%. For example, when a tray for ham or the like is formed, the function of the container is satisfied by strongly pressing the rib portion, and the unnecessary portion after punching the container can separate the film and the foamed sheet of different materials and collect the recovered resin. Can be reused.

In order to keep the cell size on the surface of the foamed sheet within a specified range and adjust the peel strength from the aluminum foil,
For example, a polystyrene resin is supplied to an extruder, a foaming agent is added to the molten polystyrene resin, and the shape or size of a mold or slit, or air cooling is used for control. If the cell size is 0.5 mm or less, a chrysanthemum pattern is generated on the foamed sheet. To prevent the chrysanthemum pattern from being generated, press the roll with air while blowing it.
Wind up. As a method to blow air,
In an amount of ^{0.01m 3 / m 2 ~0.4m 3 /} m 2 at 40 ° C. Control - to Le. By such a method, an aluminum foil with an adhesive is attached to a foam sheet having a cell size in a desired range by a heat roll or the like, and cooled within 2 seconds, or the foam sheet and the adhesive layer are laminated. Are co-extruded to fuse aluminum foil, or
The laminated foamed sheet of the present invention can be obtained by means of applying an adhesive to the foamed sheet by coating, laminating an aluminum foil on the foamed sheet, and laminating the foil with a heat roll or the like.

With respect to the peel strength between the foamed sheet and the aluminum foil, if it is less than 5 g / 25 mm, it will peel off during use as a container, or if a thin aluminum foil is used (about 20 μm or less), there will be wrinkles during molding. Cause the occurrence of. On the other hand, if it exceeds 310 g / 25 mm, the aluminum foil may be lost when peeled. However, when the lid is filled with a replacement gas such as CO ₂ or N ₂ to form an eel peel, the peel strength must be 200 g / 25 mm or more. The peel strength is measured by Orientec Cor
20 minutes per minute using the poration RTM-500
It is a measured value when a speed of 180 mm is peeled off.

The polyolefin film used for laminating via aluminum foil and adhesive includes linear low density polyethylene, high density polyethylene, low density polyethylene, propylene homopolymer, ethylene / propylene random polymer, ethylene / propylene block polymer. -, Ethylene-propylene-butene-terpolymer, ethylene-vinyl acetate copolymer, ethylene-unsaturated carboxylic acid ester copolymer (for example, ethylene-methyl methacrylate copolymer), ethylene-unsaturated Carboxylic acid metal salt copolymer (for example, ethylene-magnesium (or zinc) acrylate copolymer), propylene-vinyl chloride copolymer, propylene-butene copolymer, propylene-maleic anhydride copolymer, propylene-olefin copolymer (Propylene-D Ethylene copolymer, propylene-butene-1 copolymer) modified product of polyethylene or polypropylene with unsaturated carboxylic acid (for example, maleic anhydride), ethylene-propylene rubber, atactic polypropylene, etc., polyethylene, ethylene-propylene. Copolymers, propylene-butene-1 copolymers and these 2
Examples of the film include a mixture of two or more kinds. Also, these films may be laminated. As the crystalline polypropylene resin, crystalline propylene homopolymer is preferable, but other than that, mainly crystalline polypropylene-ethylene copolymer, polypropylene such as crystalline ethylene-propylene-gen terpolymer are mainly used. Polymers may be mentioned.

In the present invention, when laminating the foamed sheet and the aluminum foil, laminating with an adhesive or heat rolling.
It may be any of laminated layers and the like. The adhesive that can be used may be any of a thermoplastic resin adhesive, a thermoplastic elastomer adhesive, a pressure sensitive adhesive, a hot melt adhesive, a rubber adhesive and the like. In the case of thermocompression bonding, the film is heated and pressure bonded from the side opposite to the joint surface with a heat roll. In this case, the surface of the roll which is heated and pressure-bonded is subjected to chrome plating or Teflon coating to prevent adhesion or stickiness to the heated aluminum foil with a film. In the present invention, it is preferable that the joint surface is heated by a heating device together with the thermocompression bonding by a heat roll.

Further, a foam sheet made of a resin different from that of the foam sheet.
It can also be applied to a laminated foam with a sheet. For example, expanded polystyrene sheet (PSP) and polyethylene (PE)
For example, an aluminum foil is adhered to or sandwiched with a foam sheet and the foamed PE and PSP are peeled off and collected after use. Even a single foam sheet foamed using recycled materials (recycled materials used, such as recovered materials such as trays and bowl containers) can be used for food containers if a barrier such as laminating aluminum foil is sufficiently performed. can do. Also, using a co-extrusion, even if a single-layer or multi-layer barrier film is adhered to a foam sheet in which the foam of the recovered raw material is sandwiched on one or both sides with the foam of the virgin raw material, It can be used for food containers. Even in this case, it is safer to stack aluminum foil.

When a foamed sheet having a desired property and an aluminum foil or a film-laminated foamed sheet and an aluminum foil are laminated with an adhesive interposed, a common thermoplastic resin is used as the adhesive. A system, a comb system, or a composite system can be used, but an ethylene-vinyl acetate copolymer, an ethylene-methyl acrylate copolymer, an elastomer (tuffprene, toughdec), or the like is easy to use. The thickness of the adhesive must be 2 μm or more when the cell size on the surface of the foamed sheet is 0.1 to 0.5 mm. This is because the peel strength is not stable due to the unevenness of the bubbles. The lamination of the foamed sheet and the aluminum foil is carried out by extruding the foamed sheet and the adhesive layer by a coextrusion method and then applying a heat roll.
You can go with Le. The reason is stability, workability, and economical efficiency. In the extrusion method, an adhesive layer may be interposed between the foamed sheet and the aluminum foil, in which case an adhesive that can be used is ethylene-vinyl acetate copolymer, methyl methacrylate methacrylate polymer Tuffrene, Tuftec or the like. . Further, in the laminated foam sheet of the present invention,
The aluminum foil may be laminated not only on one side of the foamed sheet but also on both sides. In the present invention, for example, in order to prolong the shelf life of the contents, an aluminum foil is used as a laminate in which a foam sheet is preliminarily kneaded with an antibacterial agent such as silver ion, wasabi pouring solution, and an aluminum foil. It can be placed on the inside and laminated on the foam sheet with the adhesive layer, and then separated after use.

[0023]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 Polystyrene resin having MI of 1.5 (HRM-
2) 100 parts by weight of fine talc powder as a cell adjuster was added.
8 parts by weight was added, and this was supplied to an extruder having an inner diameter of 90 mm and uniformly mixed to obtain a foamed sheet raw material. This foam sheet material was fed to the extruder at a rate of 85 kg / hr,
Butane (i-butane) as a blowing agent
Was added, and the mixture was extruded from the die at the tip of the extruder. The thickness of the foamed sheet was 2.4 mm, the basis weight was 245 g / m ² , and a laminated film 56 μm composed of EVA (VAC content 11%) and 20 μm aluminum foil was heat-rolled 180 on the foamed sheet.
Fusion was performed at a temperature of 8 ° C. and a speed of 8 m / min, and after about 1 second, cooling was performed with a cooling roll set at 18 ° C. Obtained laminated foam sheet
The peel strength between the foamed sheet and the aluminum foil was measured 5 times. That is, when n = 5, the values are 185 g and 1 respectively.
It was 89 g, 192 g, 182 g, and 195 g. Therefore, the peeling strength is 189g, and the variation (maximum-minimum) /
The average was 100 = 6.9%. (Peel strength is 25 mm for sample width and 20 for Tensilon RTM-500.
It is a measured value when peeled 180 degrees at a speed of 0 mm / min. ) This laminated foam sheet is molded into a round plate (14
(8 mm diameter × 13 mm depth) was molded at an ambient temperature of about 120 ° C. for a cycle of 18 sec, and there were no wrinkles, no holes, no moldability and no peeling problem.

Comparative Example 1 By the same method as in Example 1, 0.08 parts of fine talc powder was collected. The thickness of the foam sheet is 1.9 mm, and the basis weight is 233.
g / m ^2, where the same film as in Example 1 were fused under the same conditions, the peel strength was 283 g. When the film was peeled off by hand, the aluminum foil was cut. The peel strength is n = 5, and the measured values are 335 g, 227 g, 310, 255.
g and 289 g. Therefore, the balance (maximum-minimum) /average×100=38.2%.

Example 2 Polystyrene resin having M1 of 2.1 (685 made by Asahi Kasei) 1
0.7 parts by weight of talc fine powder was added to 00 parts by weight as a bubble adjusting agent, and this was supplied to an extruder having an inner diameter of 90 mm and uniformly mixed to obtain a foam layer raw material. This foam layer material is
It was supplied to the extruder at Kg / Hr, melted at 225 ° C., butane (i-butane / n = 63/35) was added as a foaming agent, and the mixture was extruded from the entire die at the extrusion tip. At this time, from the outer balloon outer ring attached to the tip of the mold, 0.
An amount of 15 Nm ³ / m ² of air was sprayed onto the sheet.
Also, from the inside of the balloon, 1.5 kg / cm ² of air
Cooled in. EVA (VAC content 20%)
2. A laminated film consisting of 10 .mu.m (dry laminating) aluminum foil, about 12 .mu.m in heat roll 145.degree. C., speed 3.
Fusion was performed at 0 m / min, and after about 2 seconds, cooling was performed with a cooling roll set at 22 ° C. Foaming sheet of the obtained laminated foam sheet
The peel strength between the aluminum foil and the aluminum foil was measured 5 times. That is, n =
In 5, it was 30 g, 22 g, 28 g, 24 g, 26 g. The variation was 30.7%, which was slightly large. A circular plate (148 mm type × 1
When 3 mmH) was molded at an ambient temperature of 120 ° C. for 14 sec, there was no perforation, but some wrinkles were noticeable. There was no problem of peeling.

Example 3 Example 2 was applied to a foam sheet extruded in the same manner as in Example 2.
The same laminated film as the heat roll 145 ℃, speed 7m
/ Min fused. The peel strength of the obtained laminated foam sheet was measured, and when n = 5, 4 g, 5 g, 7 g, 5 g,
It was 5 g. The variation was 57,7%. When this was molded at 120 ° C. for 14 seconds, there were no holes, but wrinkles became noticeable. There was no problem of peeling.
Even if the peel strength is partially less than 5 g / 25 mm width, there will be no problem depending on the application unless peeling occurs during molding.

Comparative Example 2 In Example 3, when the temperature of the heat roll was lowered to 130 ° C., the peel strength was n = 5, and the peel strength was 2 g, 3 g, 6 g, 4 g and 3 g. The variation was 111%. This is 120
When molding was carried out at a temperature of 14 nc (the same conditions as in Example 2), there were no holes, but there were many wrinkles, and the foamed sheet and peeling of the aluminum foil occurred.

Example 4 Polystyrene resin having MI of 1.5 (HRM-made by DENKA)
2) To 100 parts by weight, 1 part by weight of talc fine powder was added as a bubble control agent, and this was supplied to an extruder having an inner diameter of 90 mm and uniformly mixed to obtain a foam layer raw material. This foam layer material is 85K
The mixture was fed to a 90 mm extruder at a rate of g / hr and melted at 235 ° C., butane gas (i-butane 6) was added as a foaming agent.
5%, n-butane 35%) was added, and the mixture was extruded into a die at the tip of the extruder. On the other hand, in addition to the polystyrene resin, an ethylene-vinyl acetate copolymer (EVA25K VAC content of Mitsubishi Yuka Co.
%) And is co-extruded together with the foamed resin at a resin temperature of 165 ° C. into a mold having a diameter of 105 mm and a slit width of 0.75 mm to form a foamed polystyrene sheet and an adhesive layer laminated foam sheet.
Manufactured. The resulting laminated foam sheet foam (PS
The thickness of P) was 2.6 mm, the basis weight was 352 g / m ² , and the thickness of the adhesive layer was 38 μm. About 10 in this foam sheet
Heat roll 220 ℃, 0μm aluminum plate, heat generator about 2
Approximately 2s using 50 ° C and fusion at a speed of 4m / min
After ec, it was cooled by cooling at 20 ° C. The peel strength between the foamed sheet of the obtained laminated foamed sheet and the aluminum plate was measured. 15g, 18g, 13g, 13g, 17 with n = 5
The average peel strength was 15.2 g / 25 cm width and the variation was 32.9%. This is aluminum foil 6
Since it is 0 μm or more, molding is difficult, but assembly of boxes etc. can be done without problems. Example 4 when the aluminum plate was about 132 μm
When bonded under the same conditions as above, the heat loss of the bonded surface of the foamed sheet became large and the sample peeled off when a sample having peel strength was prepared.

Example 5 An aluminum foil having a thickness of about 58 μm was melted on a foam sheet prepared in the same manner as in Example 4 using a heat roll of 220 ° C. and a heat generator of about 230 ° C. at a speed of 4 m / min. 2 seconds after wearing
It cooled with 0 degreeC cold air. The peel strength between the foamed sheet and the aluminum foil of the obtained laminated foamed sheet was measured. When n = 5, the weight was 152 g, 158 g, 162 g, 174 g and 144 g, and the average peel strength was 157.8 g / 25 mm width and the variation was 19.0%. A round plate (148 mm diameter x 13 mmH) was used to form this laminated sheet in a molding machine at an ambient temperature of about 140.
When molded at 15 ° C. for 15 seconds, there were no wrinkles and no peeling occurred.

Example 6 Used polystyrene trays collected from the market were washed, crushed and pelletized by a recovery machine. M1 of this pellet was 6.7 (measured by the method of JIS-K6870), and butadiene having a particle size of about 1 to 6 μm as a rubber component was mixed in a salami structure of 0.1%. This pellet has a particle size of about 1μ
0.5 parts of talc of 0.5 m and barium stearate of 0.3 are added, bubbles are adjusted and supplied to a 90 mm extruder (L / D = 40), and after melting at a maximum temperature of 230 ° C., normal butane / isobutane = 6 / After adding 2.2% in a ratio of 4 and adjusting to the proper foaming temperature, the foaming sheet was extruded from the die at the tip of the extruder and at about the same time, 0.15 Nm ³ / m ^{2 of} air was added to extrude the foaming sheet. The thickness of the foamed sheet is 1.5 mm, the basis weight is 320 g / m ² , and an aluminum foil having a thickness of about 20 μm is attached to this sheet with an extruder equipped with a T-die. : XG-600S) was adhered while being extruded. The peel strength between the foamed sheet of the obtained laminated foamed sheet and the aluminum foil was measured. 320g with n = 5, 32
It was 9 g, 301 g, 291 g, and 292 g, and the average peel strength was 307 g / 25 mm width and the variation was 12.1%. A round plate 148 mm diameter x 1 of this laminated sheet is molded with a molding machine.
When 3 mmH was molded at an ambient temperature of about 135 ° C. for 13 seconds, there was no perforation, no wrinkles, and no peeling occurred. However, the range of molding conditions is narrow and the molding cycle is 11s.
When dropped to ec, perforation occurred.

Comparative Example 3 A foamed sheet extruded under the same conditions as in Example 6 and an aluminum foil of about 20 μm were used, and an extruder equipped with a T-die was used to produce about 68 μm.
m EVA (VAC 20%) was extruded and adhered. n
= 331 g, 325 g, 338 g, 352 g, 31
The average peel strength was 331.2 g / 25 mm width, and the variation was 12.7%. When the aluminum foil of this laminated sheet was peeled off by hand, it sometimes took time for the aluminum foil to remove salmon. A circular plate 148 is used to form this laminated sheet with a molding machine.
mmsease x 13 mmH at an atmospheric temperature of 135 ° C for 13 seconds
When molded with c, there were no wrinkles or peeling, but some perforations occurred. This is because the adhesive strength is strong and the aluminum foil is not displaced during molding.

Example 7 Homopolypropylene (manufactured by Highmont) XPF-814
In addition, a bubble control agent DIBRO-No2 (manufactured by Dainichiseika) 0.2
Part, and a cylinder of 90φ extruder-temperature 230 ℃ ~ 2
I-Butane was added at 45 ° C., and the mixture was flown into the extrusion die at a rate of 69 Kg / Hr, while EVA (VA
6%) was passed through a confluent die, flowed into an extrusion die and coextruded to obtain a laminated sheet. This laminated foam sheet had a thickness of 1.48 mm and a basis weight of 355 g / m ² . About 20 μm of aluminum foil was fused to this foamed sheet at a speed of 4.5 m / min using a heat roll 195 ° C. for about 3 seconds.
Cold air of 20 ° C was applied to the vine. When the peel strength between the foamed sheet and the aluminum foil of the obtained laminated foamed sheet was measured,
It was 78 g, 71 g, 83 g, 87 g, and 92 g at n = 5. Therefore, the average peel strength was 82.2 g / 25 mm width and the variation was 25.5%. This laminated sheet was molded by a molding machine in a round plate (148 mm diameter × 13 mmH) at an atmospheric temperature of about 155 ° C. for 21 sec cycles. No wrinkles or holes were formed, and there was no problem of moldability or peeling.

The results of the above Examples and Comparative Examples are shown in Table 1, Table 2, Table 3 and Table 4.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

[0037]

[Table 4]

[0038]

As described above, according to the present invention, a laminated foam sheet can be produced by a hot laminating laminating machine by combining a foam sheet having specific bubbles and an aluminum foil. Since the laminated foam sheet has an appropriate peel strength, it is suitable as a food tray and container.

Claims (3)

[Claims] 1. A laminated foam sheet in which an aluminum foil is laminated on at least one surface of the foam sheet, and the cell size of the surface of the foam sheet on the side where the aluminum foil is laminated is 0.5 mm or less, The aluminum foil is 5g / 25mm width-310g
A laminated foam sheet characterized by being laminated so that it can be peeled off from the foam sheet with a force of / 25 mm width. 2. A container formed from a laminated foam sheet in which an aluminum foil is laminated on at least one surface of the foam sheet, wherein the aluminum foil has a width of 5 g / 25 mm to 310 g / 25.
A container characterized in that it can be peeled from a foam with a force of mm width. 3. The laminated foam sheet according to claim 1, and the container according to claim 2, wherein the foamed sheet is a reused product after use.