JPH07187192A - Container - Google Patents

Abstract

(57) [Abstract] [Objective] A container comprising a laminated foam sheet of a film and a foam sheet suitable for use in food trays and the like. A container formed of a laminated foam sheet in which a single layer film or a laminated film is laminated on at least one side of a foam sheet, and having a flange portion around the opening, and the film and the foam sheet in the collar portion. 100g peel strength
/ 25 mm width to 400 g / 25 mm width, and the peel strength between the film and the foamed sheet in the container body other than the collar portion is 5 g / 25 mm width to 200 g / 25 mm width.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container comprising a laminated foam sheet, which is a monolayer or multilayer film suitable for use as a food container and a foam sheet.

[0002]

2. Description of the Related Art Expanded polystyrene, expanded polyester,
The trays and containers of foam made of synthetic resin such as foamed polyolefin (hereinafter sometimes referred to as trays) are inexpensive, pure white and have a clean feeling, so they are already cooked including vegetables, meat or fish. It is widely used as a variety of food containers, including used foods.

However, recently, after these trays are used, there is a demand for collection and reuse. However, the inner surfaces of these trays are difficult to clean, and for example, trays containing cooked food may be extremely unsanitary and sometimes produce a foul odor if they are discarded with the food left intact. When storing food, such as ham, foam foam
I use a film that is different from that of G. Therefore, there are various problems in collecting and reusing this tray.

As one of these recovery methods, 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. -38942
(See the official gazette). However, no good proposal has yet been made regarding the recovery and reuse of trays obtained by bonding different kinds of films.

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, the film is weak and thus cut during peeling, or the adhesive strength is weak during use. There are various problems such as peeling, and further, when the adhesive strength is large, it cannot be peeled off even after use. In addition, when a container is formed of a laminated foam sheet, unnecessary parts (residuals of the container) that are generated must be separated when a film and a foam sheet of different materials are used. Therefore, expensive equipment is required. Therefore, some treatment is incinerated or landfilled.

[0006]

SUMMARY OF THE INVENTION The present inventor has improved the above-mentioned drawbacks and can easily form a foam sheet without tearing the film.
As a result of various studies on a laminated foam sheet that can be peeled from the foam sheet, the present invention has been completed. The object of the present invention is to laminate a film that can be easily peeled without tearing the film from the foam sheet and is suitable for a food tray. A foamed sheet is provided, and the unnecessary portion (remaining punching of the container) during the molding of the tray is also continuously formed so that the monolayer film or the laminated film and the foamed sheet can be separated. It provides a tray that can be easily collected and has no functional problems.

[0007]

SUMMARY OF THE INVENTION The gist of the present invention is to mold from a laminated foam sheet in which a monolayer film or a laminated film (hereinafter sometimes referred to as a film) is laminated on at least one surface of the foam sheet. In a container having a flange around the opening, the peel strength between the film and the foamed sheet in the flange is 100 g / 25 mm width to 400 g / 25 m.
m width, and the peel strength between the film and the foamed sheet in the container body other than the collar portion is 5 g / 25 mm width to 200.
A container having a width of g / 25 mm. That is, in the present invention, the peel strength between the foam sheet of the single-layer or laminated film laminated on at least one surface of the foam sheet constituting the container is determined by the seal between the portion constituting the container body and the lid. The peel strength of the former is made smaller than that of the latter, and the peel strength of the latter is 100 g / 25 mm width to 400 g / 25 m.
The width is m, and this portion is also provided with easy peeling property.

The present invention will be described in detail. The foamed sheet used in the present invention is a foamed polystyrene-based sheet (hereinafter sometimes referred to as PSP), a foamed polyolefin sheet, a foamed polyester sheet, or the like. A polystyrene resin, a polyolefin resin, a polyester resin, or the like is supplied into the extruder, heated and kneaded to be melted, and a foaming agent is added to the resin in a molten state for production. 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. A foamed sheet composed of a copolymer or polystyrene homopolymer containing 50% by weight or more of a system monomer, and acrylic acid, methacrylic acid, or these as a monomer copolymerizable with a styrene system monomer. The ester, 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 expansion ratio is 1.5 to 2
It is about 0 times. In forming the foamed sheet, a compounding agent which is usually used in the resin, such as a cell regulator and a pigment, may be added. The thickness of the foamed sheet in the present invention is not particularly limited, but it is usually sufficient that it has the thickness of the foamed sheet constituting this type of tray.

The cell size of the surface of the foamed sheet used in the present invention on which the films are laminated is 0.5 mm or less,
In addition, the surface smoothness Rmax is preferably controlled to 450 μm or less, and the stability of the adhesive force can be achieved by satisfying such conditions.

In the present invention, for the cell size of the surface, the film laminated on the surface of the foamed sheet is peeled off, and the number of bubbles on one straight line 10 mm on the short diameter bubble side is measured,
The average diameter (d) of bubbles is a value calculated by the following formula. d = 10 / number of bubbles However, in the case of high density products where the entire surface is not filled with bubbles, the total length without bubbles is subtracted from 10 mm of the molecule in the formula.

In the present invention, the cell size value measured by this method is preferably 0.5 mm or less,
If the thickness is 0.5 mm or more, it is difficult to reduce the surface smoothness to 450 μm or less even if a heat roll treatment or the like is performed (generally, when the temperature of the heat roll is increased, foaming is further deteriorated). Also, stable adhesion does not occur and it is difficult to meet the purpose. This value can be controlled by a method such as compounding, die, slit, and air cooling. When the bubbles are 0.5 mm or less, chrysanthemum patterns are generated on the foam sheet. In order to reduce this, the cooling air is heated at 5 to 40 ° C. to 0.01 m ³ / m ²
Control in an amount of ˜0.4 m ³ / m ² .

The surface smoothness of the foamed sheet is Rmax, which is the maximum value measured by a surface shape analyzer (SAS-2010 manufactured by Meisho Machine Co., Ltd.), and this value is 450 μm.
Below. If the surface smoothness exceeds 450 μm in Rmax, it is difficult to control the adhesive force, and if the adhesive is peeled off easily by hand, partial delamination (gas from inside expands due to heat during molding, (Become a bubble) occurs and does not meet the purpose. To adjust the surface smoothness, means such as air bubble size (currently the smallest air bubble is made up to 5 μm), the amount of air, and heat roll are used.

The film layer laminated on the foamed sheet may be either a single layer film or a laminated film. As the polymer constituting the laminated single layer film or laminated film, 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-ethylene copolymer, propylene-butene-1 copolymer) polyethylene or polypropylene Unsaturated carboxylic acid (for example, maleic anhydride) modified product, ethylene-propylene rubber, atactic polypropylene and the like can be mentioned, and polyethylene, ethylene-propylene copolymer and propylene-butene-1 copolymer can be mentioned. -One or more Films consisting of compounds can be used.

As the film layer, a film having a gas barrier property as a single layer film may be used, and in the case of a laminated film, a film having at least one layer having a gas barrier property may be laminated, in which case it is laminated by heat. Or laminated using a binder (for example, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer and styrene-butadiene (block) copolymer elastomer, or a mixture thereof). Is also good. Further, a metal foil such as an aluminum foil or a stainless foil can be used as the film layer.

As the above-mentioned crystalline polypropylene resin, crystalline propylene homopolymer is preferable, but other than that, polypropylene such as crystalline propylene-ethylene copolymer and crystalline ethylene-propylene-gen terpolymer. Polymers mainly composed of Its thickness is about 5 to 500 μm. The thickness of the film laminated on the foamed sheet is 5 to 500 μm, and when a film alone having a film thickness of less than 5 μm is extruded, pinholes and the like are likely to occur. When the laminated foam sheet of the present invention is produced by coextruding a film having a thickness of less than 5 μm,
The film may have a puncture hole, and if the thickness is 500 μm or more, the economy is poor, and in the case of thermal lamination laminating, the heat capacity of the film is too large and the foamed sheet is exposed to heat. In addition, since it may separate from the foamed sheet during molding, molding is difficult.

Lamination of the foamed sheet and the film may be carried out by a coextrusion method in addition to the pressure bonding by a pressure roll or a heat roll. The reason is stability, workability, and economical efficiency. In the coextrusion method, an adhesive may be interposed between the foamed sheet and the film, and the adhesive that can be used in this case is ethylene-vinyl acetate copolymer, methyl methacrylate polymer and the like. In addition to the above, when laminating the foamed sheet and the film, an adhesive may be used for laminating. As the adhesive, a general thermoplastic resin type, a rubber type or a composite type can be used, but an ethylene-vinyl acetate copolymer, an ethylene-methyl acrylate copolymer elastomer (tuffrene, tough deck) or the like is easy to use. In the laminated foam sheet of the present invention, the film may be laminated not only on one side of the foam layer but also on both sides.

Examples of the gas barrier film to be laminated on the foam sheet include ethylene vinyl acetate-based copolymer, polyvinyl alcohol, polyvinylidene chloride, polyamide, polyester, polyacrylonitrile, vinylidene chloride-acrylonitrile copolymer, Acrylonitrile-based methyl methacrylate / butadiene copolymer, nylon 6, biaxially oriented nylon, biaxially oriented polyethylene terephthalate, biaxially oriented polypropylene, high density polyethylene, ionomer resin (for example, registered trademark sa -Phosphorus) or the like, or a metal vapor deposition film alone, or a film in which these polymers are combined is used. Further, in the present invention, for example, in order to prolong the shelf life of the contents, an antibacterial agent such as a film or a gas barrier film in which an antibacterial agent such as silver ion or wasabi pouring solution is previously kneaded in a foamed sheet is used. It is also possible to laminate and further laminate a film thereon to form a container, and separate the container after use.

In the present invention, the peel strength between the foam sheet and the monolayer or laminated film of the container body of the molded container is in the range of 5 g / 25 mm width to 200 g / 25 mm width. If it is less than 5 g / 25 mm, it peels off during use as a container, while on the other hand, 200 g / 25 mm
If it exceeds, it becomes difficult to continuously peel off unnecessary parts during molding, and therefore workability during molding is not good. This peel strength is Orientec Corporation
It is a measured value when using RTM-500 and peeling 180 degrees at a speed of 200 mm per minute.

In the present invention, the laminate of the foam sheet and the gas barrier film may be laminated with an adhesive, laminated with a heat roll, laminated with a co-extrusion or 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, heating and pressing are performed from the side opposite to the joint surface with a heat roll. In this case, the surface of the roll to be heated and pressure-bonded should be chrome-plated or Teflon-coated.
To prevent adhesion with the heated 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.

When a container is molded using such a laminated foam sheet, the effect is small unless the gas barrier film is laminated inside the container. Therefore, the lid is lightly sealed on the film. In this case, if the peeling strength between the film and the foamed sheet is less than about 100 g / 25 mm width, the film may be peeled off when the lid is peeled off because the container is used, and preferably 200 g /
It is better to have a width of 25 mm or more. In addition, 400g / 25
If the width exceeds mm, peeling is not easy.

In order to adjust the peel strength between the foamed sheet of the present invention and the film, for example, polystyrene resin is fed to an extruder, and a foaming agent is added to the molten polystyrene resin,
After extrusion foaming, heat roll treatment to wind up, or to make surface bubbles of the foam 0.5 mm or less and to suppress generation of chrysanthemums, press and roll with air while blowing. It is possible to attach a single layer or a laminated film to the foamed sheet produced in (1) with a heat roll or the like and cool it within 2 seconds.

Since the peeling strength of the lid portion is related to the working shape of the die, the molding press pressure and the die clearance, a foam is formed between the portion sealing the lid and the other portion. As a method of providing a difference in peel strength from the film, a convex / concave line is formed at the position where the lid of the molding die is sealed, or knurled, peared, or ring-shaped is gently attached to the flange of the container. If a groove is added to the groove, the peel strength will be 20 to 200% only in the part pressed by the mold press during molding.
The above can be solved and the problem can be solved.

For example, when a bowl container or the like is molded, the function of the container is satisfied by pressing the brim portion strongly, and the unnecessary portion after punching the container can be recovered by separating the film and the foamed sheet of different materials. The resin can be reused. The same effect can be achieved by foaming the binder or filling the binder with filler.
When it is mixed, it becomes more remarkable, the difference between the strength of the collar portion and the peeling strength of the unnecessary portion becomes large, and peeling becomes easy. (The part where the collar is pressed hard becomes stronger, and the peeling of the defective part becomes weaker.)

Next, a mold for producing the container of the present invention is shown in FIG. As shown in FIG. 1, a temperature control pipe 2 is provided inside the mold 1, and a portion 3 corresponding to the collar portion is provided.
Is protruding. Then, as shown in FIGS.
2 shows a groove formed along the brim, FIG. 3 shows knurling, and FIG. 4 shows pearing, but these shapes are not limited.

[0028]

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 4.1 (HRM-manufactured by Denka Corporation)
5) 100 parts by weight of fine talc powder as an air conditioner.
Add 5 parts by weight and 0.2 parts by weight of hydrocellulose CF,
This was fed to an extruder with an inner diameter of 90 mm, melted at 225 ° C., butane gas was added as a foaming agent to this, and the extrusion amount was 9
It was extruded from a die at the tip of a 0 Kg / H extruder. And
The S roll (temperature control roll) temperature of the take-up machine was adjusted to 130 ° C. and taken. The thickness of the foam sheet is 2.35 mm and the basis weight is 285.
The g / m ² and the surface roughness Rmax were 135 μm.
EVA (VAC content 11%) / NA / EV
A laminated film of 110 μm made of OH / PS was fused at a heat roll of 170 ° C. and a speed of 7 m / min, and after about 3 seconds, 2
It cooled with the cooling roll set to 1 degreeC. The peel strength between the foamed sheet and the film of the obtained laminated foamed sheet was measured 5 times. The average peel strength was 86 g, and the average was (maximum-minimum) /average×100=10.5%. (Peel strength is 25 mm sample width, Tensilon RTM-500
Is a measured value when peeled 180 degrees at a speed of 200 mm / min. )

Mold for molding (bowl container 172 mm diameter x 52
When the plug of (H) is molded into a container and the lid is sealed, a plug part (called a brim) is knurled (groove pitch 2 mm, depth 1 mm) using a molding die. -Heater temperature approx. 395 ° C 5.5 sec /
It was formed into a bowl container by cycles and punched continuously. The punching residue of the container was able to be separated while peeling the film and the foam. The peel strength between the foam and the laminated film at the seal (collar) with the lid of the molded container was 165 g / 25 mm width, and the peel strength at the other part was 92 g / 25 mm width, and the punching residue (ear portion). Peel strength was 88 g / 25 mm width. At this time, the foam thickness immediately before molding in the molding machine is about 4.8.
The mold clearance was 2.5 mm at the brim where the lid of the molding die was sealed. The laminated film was not peeled off even after peeling off the lid after sealing the container. Comparative Example 1 The laminated sheet of Example 1 was molded under the same conditions as in Example 1 except that the mold clearance at the brim of the portion where the lid of the molding die was sealed was 3.5 mm. Part (rib)
The peel strength was 99 g / 25 mm width, and when the lid was peeled off after sealing, the laminated film was peeled off at the same time.

Example 2 Polystyrene resin having MI of 4.1 (HRM-made by DENKA)
5) To 100 parts by weight, 5 parts by weight of talc fine powder was added as a bubble control material, and this was supplied to an extruder having an inner diameter of 90 mm,
It was melted at 235 ° C., butane gas (iso / normal = 68/32) was added as a foaming agent, and the mixture was extruded from a mold at the tip of the extruder. And the S roll of the take-off machine (temperature control roll
The temperature was raised to 130 ° C. and the temperature was taken off. The foamed sheet has a thickness of 1.95 mm, a basis weight of 370 g / m ² , and a surface roughness Rm.
The ax was 67 μm. EVA (VAC
Laminated film consisting of 11%) / PS about 105 μm
With a hot roll of 220 ° C and a hot air temperature of 90 ° C for a speed of 4 m /
Fusing at min, and after about 5 seconds, it was cooled by a cooling roll set at 22 ° C. The peel strength between the foamed sheet and the film of the obtained laminated foamed sheet was measured 5 times. Average peel strength is 1
At 63g, the balance (maximum-minimum) / average x 100 =
It was 5.3%. (Peel strength is 25 mm sample width, 200 mm / min with Tensilon RTM-500
It is the measured value when peeled 180 degrees with the speed of. ) This laminated foam sheet was placed in a bowl using a molding machine having the same molding die as in Example 1 and the container was heated at a heater temperature of about 405 ° C. for 5.6 se.
Molded in c / cycle and punched continuously. At this time, the punching residue (ear) was rolled up and left for one day, and the punching residue (ear) of the container was separated into a film and a foam, whereby separation was possible. The peel strength between the foam and the laminated film at the seal portion with the lid of the molded container was 261 g / 25 mm width and the other portion was 196 g / 25 mm width. 184 peeling of the ear
g / 25 mm, the mold clearance at the rib at the portion where the lid of the molding die is sealed is 1.9 mm, and the secondary thickness of the laminated sheet immediately before molding is 3.7 mm. It was The laminated film was not peeled off even if the lid of this container was peeled off after sealing.

Comparative Example 2 When the hot air temperature was raised to about 105 ° C. under the laminating condition of the laminated film of Example 2 and the foamed sheet, the peel strength of the ears became 218 g / 25 mm width on average and the width of the ears was increased. A part of the film was cut at a point of about 5 mm or less.

Example 3 Used polystyrene trays collected from the market were washed and ground, 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 talc and 0.2 calcium stearate
Then, foam is prepared and supplied to a 90 mm extruder (L / D = 40) and melted at a maximum temperature of 220 ° C. Then 2.5% is added as a foaming agent in a ratio of normal butane / isobutane = 4/6 to obtain an appropriate foaming temperature. After that, when air is extruded from the die at the tip of the extruder and foamed, air is added at almost the same time as 0.12 Nm ³ / m ² ,
It was collected without using a heat roll. Foam sheet thickness is 1.1
5 mm, basis weight 335 g / m ² , surface Rmax is 235
was μm. After leaving this sheet for 1 day, 4
HI (impact-resistant resin rubber content about 6%) film with a thickness of 81 μm was heated at 185 ° C. in a hot roll and 155 ° C. in hot air at 5 m / m
Immediately after heating and fusing with an in-speed, the film side was cooled by touching a roll in which cooling water of 21 ° C. was made to flow. The peeling strength between the foamed sheet and the film of the obtained laminated foamed sheet was measured 5 times. Average peel strength is 55g / 25
The variation in 1 mm width was 15.6%. This laminated foam sheet has a flange portion knurled (groove pitch 2 mm, depth 1.5 mm) to form a gratin container mold 155 L × 125 W.
Molding was performed at a heater temperature of about 410 ° C. for 7.8 sec / cycle using a molding machine having × 31H. At the same time, when the punching residue (ear) of the container was peeled off to the film and the foam, it could be made smooth without any problem. The peel strength of the lid seal of the molded container was 108 g / 25 mm width on average. The mold clearance at the flange was 1.2 mm, and the secondary thickness of the laminated sheet immediately before molding was 2.1 mm. The laminated film was not peeled off even if the lid was peeled off after sealing the container.

Example 4 Homopolypropylene (manufactured by Highmont) XPF-814
In addition, the air-conditioning agent Hydrocelol (Dainichi Seika Sales Co., Ltd.)
Add 2 parts, and use a 90φ extruder at a cylinder temperature of 230 ° C.
I-Butane was added at 245 ° C., and it flowed into the extrusion die at an extrusion rate of 71 Kg / Hr, while PS /
When HI (6% butadiene) = 1/1, it melts at 230 ° C. as a film resin and flows into an extrusion die at an extrusion rate of 22 Kg / Hr, and EVA (VA 6%) from 45φ,
With an extrusion rate of 7 Kg / Hr, flow into an extrusion die and coextrude,
A laminated sheet was obtained. The surface Rmax was 410 μm. This laminated foam sheet had a thickness of 1.41 mm, a basis weight of 420 g / m ² , and a peeling strength of 8 when the film was peeled off.
At 6 g, the variation was 27%. This laminated foam sheet
To the collar as shown in A in the figure (groove pitch 2 mm depth 1.0
mm bowl) 172 mm x 52 H with a molding machine
It was molded at 20 ° C. for 12 sec / cycle. At the same time, there was no problem when the container was punched and the punching residue (ear) was separated into a film and a foam. The peel strength of the rib portion of the molded container was 151 g / 25 mm width on average. The clearance of the mold of the collar is 0.5 mm, and it is 2 mm just before forming the laminated sheet.
The next thickness was 1.52 mm. After sealing the lid on this container, the laminated film was not peeled off even if the lid was peeled off.

Example 5 In a co-extrusion facility of the same type as in Example 4, an extruder having a diameter of 115 mm was used as an extruder for foaming, and a raw material having the same composition as in Example 3 was used at a cylinder temperature of 180 to 225.
After injecting i-butane at ℃ and cooling, it flowed into the extrusion die at 146 Kg / H, PS / HI (butadiene 6%) = 1/1 was put into an extruder of 65φ, and the cylinder temperature was about 200 ℃.
Inject 0.5% of i-butane, cool and extrude 17 kg
/ H into the extrusion die, and EVA with a 45φ extruder
(VA 11%) is heated and cooled, and the extrusion amount is 9 kg in the extrusion die.
/ H to make a laminated foam sheet. The laminated foam sheet had a thickness of 1.55 mm and a peel strength of 144 g / 25 mm width when the film was peeled off at a basis weight of 436 g / m ² . This laminated foam sheet was cast in the same mold as in Example 3 at 395 ° C.
After molding for 5.5 seconds, there was no problem in separating the foam and PS / HI sheet. The peel strength of the rib portion of the molded container was 275 g / 25 mm width on average, and the peel strength of the outside of the flange of the container was 186 g / 25 mm width on average. The secondary thickness immediately before molding was 3.05 mm, and the peel strength of the ears was 179 g / 25 mm on average.

Comparative Example 3 The foamed sheet of Example 1 was extruded with HIPS resin (VA amount 6%) heated to about 240 ° C. from a 90φ extruder to about 60 μm and air-cooled to Example 1. The same film was sandwiched and crimped. The peel strength of the foam film is 22
The width was 6 g / 25 mm, and the same mold as in Example 1 was used to mold the rib portion with a clearance of 3.1 mm. When the foam was separated from the film, cutting occurred. At this time, the average peel strength of the ears was 239 g / 25 mm width. The peel strength of the collar of the forming container was 294 g / 25 mm on average, and the peel strength of the container outside the collar was 272 g / 25 mm on average. The average thickness of the laminated foam sheet was 2.46, and the foam thickness immediately before molding was about 5.2 mm.

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

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

As described above, the present invention provides a foam sheet.
Molded from a laminated foam sheet in which a single layer film or a laminated film is laminated on at least one side of the container, and in a container having a flange portion around the opening, the peel strength between the film and the foam sheet in the flange portion and The peel strength between the film and the foam sheet in the container body other than the collar portion is made different, and the peel strength between the film and the foam sheet in the collar portion is 100 g / 25 mm width to 400 g / 25 m.
Although the film can be easily peeled off by defining the width to be m, it does not cause any trouble when the container lid is opened and unsealed, and the peeling strength of the container body is 5
By defining g / 25 mm width to 200 g / 25 mm width, the film can be peeled off very easily, and
Since the ears after the container is molded and trimmed can be easily peeled off, the workability is good, and the foamed sheet after peeling off can be reused.

[Brief description of drawings]

1a is a side view of a mold for producing the container of the present invention. FIG. b The mold surface of the part corresponding to the flange of the container of the present invention is 3
The partial detail view shown in the Example.

2A is a partially enlarged view of a portion A in FIG. 1. FIG. 2b is a sectional view taken along the line A-A 'in FIG. 2a.

3A is a partially enlarged view of a B portion in FIG. 1. FIG. b Cross-sectional view taken along the line B-B 'of FIG. 3a.

4A is a partially enlarged view of a C portion in FIG. 1. FIG. b FIG.
Sectional drawing in the CC line of a.

[Explanation of symbols]

1 Mold 2 Temperature Control Tube 3 Projection Corresponding to Collar

Claims (3)

[Claims] 1. A container formed from a laminated foam sheet in which a monolayer film or a laminated film is laminated on at least one side of a foam sheet, and having a flange portion around the opening, and the film and foam in the collar portion. Peel strength with sheet is 1
A container having a width of 00 g / 25 mm to 400 g / 25 mm and a peel strength between the film and the foamed sheet in the container body other than the collar portion is 5 g / 25 mm width to 200 g / 25 mm width. 2. The container according to claim 1, wherein the foamed sheet is a recycled product after use. 3. The container according to claim 1, wherein at least one of the film having a gas barrier property and the laminated film having a gas barrier property is a laminated film having a gas barrier property.