JPH09207973A - Container for food packaging - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a container for food packaging, which is excellent in secondary thermal formability, is excellent in heat insulation property at the time of thawing and heating of beverage or food, and can be easily held by hand by a method wherein for an integrally formed container for which a heat resistant thermoplastic resin sheet and a synthetic fiber nonwoven fabric of a specified physical property, are laminated and bonded, the nonwoven fabric forms at least the external layer of the container. SOLUTION: For this container, a non-foaming type thermoplastic resin sheet of which the heat resistant temperature is 60 deg.C or higher, and a synthetic fiber nonwoven fabric of which the apparent specific gravity is 0.01-0.4g/cm<3> , of which 20% intermediate stress at a temperature of 120 deg.C is 5kg/5cm or less, are laminated and bonded, and integrally formed. The nonwoven fabric is formed at least on the external layer of this container for food packaging, which comes into contact with hand of a human being such as a person who cooks the food. Therefore, the external layer of this container is covered with a bulky specified synthetic fiber nonwoven fabric, and even when the beverage/food is thawn and/or heated by a microwave oven, etc., the container has a non-touching property and has a merit that it can be easily held by hand. The container is also excellent in secondary thermal formability as having a low thermal stress, and easily being shaped, and the productivity is improved.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel food packaging container. Specifically, since the present invention uses a composite sheet of a specific nonwoven fabric and a thermoplastic resin sheet as a base material, it has excellent secondary thermoformability and can be thawed and / or heated for food and drink in a microwave oven or the like. The present invention relates to a novel food packaging container that is non-tactile and can be easily held by hand.

[0002]

2. Description of the Related Art Conventionally, food packaging containers have been required to be simple and functional due to changes in the food service industry and lifestyles. Especially, plastic containers are used for heating and cooking food and drink,
Thawing is widely performed using a microwave oven or the like. However, this plastic container is very hot at the moment of taking it out from the microwave oven, etc.
The current situation is that it is difficult to have.

For this reason, it has been surpassed by pasting paper or the like in a range where a plastic container is directly touched. In this case, it is difficult to laminate plastic and paper in advance and integrally mold them, and the only way is to laminate paper and the like in a plastic container shaped in advance by secondary thermoforming with an adhesive or the like. Met.

[0004]

Therefore, an object of the present invention is to provide excellent secondary thermoformability and excellent heat insulation even when food and drink are thawed and / or heated in a microwave oven, etc. It is intended to provide a food packaging container which can be easily held and is excellent in safety, and is excellent in integral moldability and design.

[0005]

Means for Solving the Problems As a result of various studies on the above problems, the inventors of the present invention composited a specific synthetic fiber non-woven fabric having bulkiness and excellent secondary thermoformability with a plastic container base sheet. By the present invention, it has been found that it is possible to provide a food packaging container which is excellent in secondary thermoformability and which can be easily held by hand with non-touch even if food and drink are thawed and / or heated in a microwave oven, etc. It came to completion.

That is, the present invention is: a heat-resistant thermoplastic resin sheet and an average apparent specific gravity of 0.
A container integrally molded with a synthetic fiber non-woven fabric having 01 to 0.4 g / cm ³ and a temperature of 120 ° C. and a 20% intermediate stress of 5 kg / 5 cm or less, and the non-woven fabric is at least the outer layer of the container. There is provided a container for food packaging, which comprises: Another feature is that the synthetic fiber nonwoven fabric is composed of hydrophobic synthetic fibers. It is also characterized in that the synthetic fiber non-woven fabric is a polypropylene long-fiber non-woven fabric composed of crimped fibers and having a partially thermocompression bonded portion. Also,

The heat resistant temperature of the thermoplastic resin sheet is 6
It is also characterized in that the temperature is 0 ° C or higher. It is also characterized in that the thermoplastic resin sheet is non-foamed. It is also characterized in that the thermoplastic resin sheet is polypropylene, polypropylene containing filler, or polyester. Moreover, the food packaging container described in any one of to is suitable for thawing and / or heating food in a microwave oven or the like.

Hereinafter, the present invention will be described in detail. The food packaging container of the present invention comprises a non-foaming thermoplastic resin sheet having a heat resistance temperature of 60 ° C. or higher and an average apparent specific gravity of 0.01 to 0.4 g.
/ Cm ³ , 20% intermediate stress at a temperature of 120 ° C is 5 kg / 5
It is a container integrally formed by laminating and joining a synthetic fiber non-woven fabric having a size of 1 cm or less, and further characterized by a food packaging container in which the non-woven fabric forms at least an outer layer of the container.

(A) Nonwoven fabric and the like It is necessary that the nonwoven fabric constituting the food packaging container of the present invention is formed on at least the outer layer of the food packaging container which is touched by the hands of a person such as a cook. Of course, the inner layer of the container may be covered. The outer layer of the container is covered with a specific non-woven fabric made of a bulky synthetic fiber as shown by an average apparent specific gravity of 0.01 to 0.4 g / cm ³ , so the food and drink are thawed in a microwave oven or the like. And / or-there is an advantage that it is non-tactile even when heated and can be easily held by hand.

The term "non-tactile" as used herein refers to the degree to which food and drink can be easily touched and held by hand even if they feel hot because they are taken out immediately after being thawed and / or heated in a microwave oven or the like. It is not constant because there are individual differences. Therefore, even if the surface temperature of the container is about 50 to 70 ° C., it is a temperature that can be held instantaneously by hand (corresponding to a temperature that can be taken out from a microwave oven or the like), and is a temperature that is felt at about 40 to 50 ° C., for example. Further, the specific nonwoven fabric of the present invention is bonded to a thermoplastic resin sheet serving as a base, and even as a composite sheet, a 20% intermediate stress at a temperature of 120 ° C. is 5 kg / 5c.
Since it is excellent in secondary thermoformability that it can be easily shaped with a low thermal stress of m or less, a non-tactile sheet such as paper is preliminarily shaped into a food container shape after a thermoplastic resin sheet is shaped in the conventional manner. There is no need to laminate and the productivity of food packaging containers is improved.

The term “20% intermediate stress at a temperature of 120 ° C.” as used herein means a measure of thermal secondary formability, which is easily measured by JIS-L-1906. The 20% intermediate stress of the hydrophobic synthetic fiber nonwoven fabric of the present invention at a temperature of 120 ° C. is 5 kg / 5 cm or less, preferably 3 kg / 5 cm or less, more preferably 0.1 kg / 5 cm to 2 kg / 5 cm. This is a characteristic required for thermoforming to obtain the food packaging container of the present invention. That is, when the intermediate stress is low at the heating temperature during the thermoforming process, it is easy to stretch and shape with a smaller force. Therefore, if the 20% intermediate stress is 5 kg / 5 cm or less at a temperature of 120 ° C. and the elongation at break is 50% or more, more preferably 70% or more at a temperature of 120 ° C., it is easy to thermoform into a large-deformation uneven shape. it can.

The food packaging container of the present invention, at least the surface of which is laminated with the non-woven fabric, is an integrated container in which the lid part and the container part are joined by the hinge part of the same body, and the lid part and the container part are separate from each other. And may be connected by a hinge if necessary. Further, when coated with the non-woven fabric, at least the surface of the food packaging container is preferably coated, but in short the object of the present invention is achieved if a portion that may come into contact with human hands is coated. Since there are individual differences in the parts that may come into contact with human hands, it is preferable to apply it to the entire surface of the food packaging container, and it is also desirable in terms of production efficiency.

The specific synthetic fiber nonwoven fabric of the present invention is preferably made of a hydrophobic synthetic fiber rather than a hydrophilic synthetic fiber from the viewpoint of the desired non-touch feeling and the function of not getting wet with water. Therefore, the synthetic fibers constituting the nonwoven fabric are mainly composed of hydrophobic synthetic fibers, but hydrophilic synthetic fibers may be partially mixed within a range not impairing the object of the present invention.
The synthetic fiber constituting the nonwoven fabric used in the present invention is not particularly limited as long as it satisfies the object of non-touch feeling, secondary thermoformability, for example, polyethylene fiber, polypropylene fiber,
A single fiber such as a polyester fiber; one or more kinds of mixed fibers or laminated fibers such as a composite fiber such as polyethylene-polypropylene, polyethylene-polyester, and copolyester-polyester can be used. The shape of the synthetic fiber is also not particularly limited, but a round shape, an irregular cross-sectional shape,
Alternatively, crimped fibers can be used advantageously.

In particular, when the synthetic fibers constituting the non-woven fabric are crimped fibers, undrawn fibers, etc., the average apparent specific gravity, which is the object of the present invention, can be lowered (high bulkiness), and the temperature is 120 ° C.
20% intermediate stress at (standard secondary molding temperature) can be lowered (good thermoformability), which is preferable. The length of the synthetic fibers constituting the non-woven fabric used in the present invention is not particularly limited, but a non-woven fabric having a fiber length of 10 mm or more or continuous filaments is desirable because the constituent fibers do not drop off. Further, the fineness of the synthetic fiber has a diameter of a certain degree or more in view of heat resistance, non-touchability, etc., for example, a relatively thick one is desirable, and generally has a diameter of 10 μm or more, preferably 15 μm or more.

In order to produce the specific non-woven fabric according to the present invention by using synthetic fibers, known spun bond method, thermal bond method, needle punch method, columnar flow entanglement method, etc. are used.
In addition, in particular, it is preferable in terms of bulkiness and thermoformability that the synthetic fibers are three-dimensionally knitted by the partial thermocompression bonding method or the heat fusion method. For example, when the synthetic fiber is three-dimensionally knitted by the partial thermocompression bonding method, the thermocompression bonding area ratio is 2 to 30%, preferably 5 to 20%, and the embossing engraving interval is 0.3 to 10%.
mm, preferably 0.5-5 mm, depth of engraving is 0.3
~ 2.0 mm, preferably 0.5-1.5 mm,
It is particularly advantageous for the purposes of the present invention.

The synthetic fiber nonwoven fabric of the present invention has an average apparent specific gravity of 0.01 to 0.40 g / cm ³ , preferably 0.03 to.
0.20 g / cm ³ , more preferably 0.05 to 0.1
When it is 5 g / cm ³ , the mutual distance between constituent synthetic fibers is large, the thickness is large, it has a volume feeling, it is excellent in bulkiness, it is non-tactile, and it is easily held even if it is touched by a cook or the like. In addition, there is an advantage in that elongation can be easily dealt with when performing the thermal secondary forming process.

The average apparent specific gravity referred to here is JIS-L-
Refers to 1096. When the average apparent specific gravity is less than 0.01 g / cm ³ , the volume feeling and bulkiness are good, but there are problems in strength and dimensional stability. On the other hand, the average apparent specific gravity is 0.40
If it exceeds g / cm ³ , the volume and bulkiness are poor,
It becomes paper-like and is inferior in non-touch feeling, and the interval between constituent fibers is small, resulting in inferior thermoformability. The hydrophobic synthetic fiber nonwoven fabric of the present invention has a basis weight of 10 to 50 g / m ² , preferably 15 to 30 g / m ² .

(B) Thermoplastic Resin Sheet The thermoplastic resin sheet which is the base sheet constituting the food packaging container of the present invention is preferably a heat resistant and non-foaming thermoplastic resin sheet. The thermoplastic resin sheet may be unstretched or stretched. Further, inorganic fillers such as calcium carbonate, clay and talc may be pre-blended in the thermoplastic resin sheet. In that case,
The content of the filler is 40% by weight or less, preferably 20 to
It is preferably 35% by weight. The thermoplastic resin sheet needs to be able to withstand processing such as cooking, thawing, and keeping heat of food with an electronic microwave oven, for example, and is required to have a certain degree of heat resistance. The heat resistance is generally required to have a processing temperature in a microwave oven of 60 ° C or higher, preferably 90 ° C or higher. Further, it is desirable that the thermoplastic resin sheet is non-foaming.

Suitable thermoplastic resin sheets include, for example, polyethylene, polypropylene, crystalline polyester, polystyrene, copolymerized polystyrene, nylon, polyvinyl chloride, polyvinylidene chloride, polyethylene terephthalate, polyphenylene ether, polyphenylene oxide, polycarbonate and the like. Examples of the thermoplastic resin sheet include a sheet and a filler-containing thermoplastic resin sheet in which an appropriate amount of a filler such as calcium carbonate or magnesium carbonate is mixed, and polypropylene and a polypropylene including a filler are particularly preferable.

(C) Manufacture of food packaging container The method for manufacturing a food packaging container of the present invention is particularly preferable if a container in which a specific non-woven fabric is laminated and bonded to a specific thermoplastic resin sheet base can be manufactured. Although not limited, for example, extrusion in which a non-woven fabric is joined to a thermoplastic resin sheet in a heated state extruded from a die of an extruder with or without an adhesive such as ethylene-vinyl acetate-based, polyethylene-based, polyamide-based, etc. Laminate (in this case a temperature of 22
0 to 230 ° C. at a processing speed of 80 to 100 m / min under the condition that the adhesive adheres to 15 to 30% by weight, preferably 20 to 25% by weight), or ethylene-vinyl acetate type, polyethylene type, polyamide type, etc. A composite sheet is obtained by laminating with an adhesive, and then the composite sheet is molded using a molding machine such as vacuum molding, vacuum pressure molding, pressure molding, and pressure press molding at a temperature of 50 to 250 ° C. for a time of 0.3. ~ 2
It is obtained by shaping for 0 seconds, preferably 100 to 160 ° C. for 1 to 3 seconds.

(D) Container for Food Packaging of the Present Invention The container for food packaging of the present invention has excellent secondary thermoformability and thaws food and drink in a microwave oven or the like, as specified by the above-mentioned specific parameters. And / or it has excellent heat insulating properties even when heated, is non-tactile, can be easily held by hand, is excellent in safety, and is excellent in integral moldability and design. Therefore, the food packaging container of the present invention has excellent secondary thermoformability, frozen foods that are thawed and heated, cup ramen that pour boiling water, containers such as instant soup and hamburgers, hot dogs,
It is useful as a container for warm food and drink such as okonomiyaki, miso soup, and coffee.

[0022]

The present invention will be described in detail with reference to the following examples, which do not limit the scope of the present invention. The following measuring method is adopted in the production of the food packaging container of the present invention. Non-tactile ◯: Touchable for 2 seconds or more. ×: Can not be held for 2 seconds by touching it. Formability ○: Form into the desired shape. ×: The object cannot be shaped into a desired shape due to tearing, ground cracking, peeling, and the like. Heat resistance ○: The container does not deform even when heated by heating the food and drink. ×: The container is deformed even when heated by heating the food and drink.

In producing the food packaging container of the present invention,
The synthetic fiber nonwoven fabric and the thermoplastic resin sheet used are as follows. (i) Synthetic fiber non-woven fabric (a) F1: Polypropylene long-fiber non-woven fabric Weight 20 g / m ² , average apparent specific gravity 0.12 g / cm ² , average fiber diameter 1.6 denier, 120% intermediate stress vertical 1 0.4 kg / 5 cm, horizontal 0.4 kg / 5 cm, breaking elongation at 120 ° C vertical 95%, horizontal 185%, thermocompression bonding area ratio 4%

(B) F2: Polypropylene long-fiber non-woven fabric with a basis weight of 30 g / m ² , an average apparent specific gravity of 0.08 g / cm ² , an average fiber diameter of 2.5 denier and a 120% intermediate stress vertical length of 1.2 kg / 5 cm. , Horizontal 0.2 kg / 5 cm, Breaking elongation at 120 ° C Vertical 225%, Horizontal 210%, Y-shaped irregular cross-section filament crimp number average 10 pieces / 25 mm, thermocompression bonding area ratio 7%

(C) F3: Non-stretched polyester long-fiber non-woven fabric with a basis weight of 50 g / m ² , an average apparent specific gravity of 0.33 g / cm ² , an average fiber diameter of 4.2 denier and a 20% intermediate stress vertical length of 120 kg of 0.8 kg. / 5 cm, width 0.4 kg / 5 cm, breaking elongation at 120 ° C vertical 180%, width 160%, thermocompression bonding area ratio 14%

(Ii) Thermoplastic resin sheet (a) R1; polypropylene resin sheet 0.5 m thick
m, (b) R2; polypropylene resin sheet, thickness 0.5 m
m, (containing 30% by weight of calcium carbonate) (C) R3; crystalline polyester resin sheet, thickness: 0.
5 mm.

(Examples 1 to 5) Non-woven fabric made of synthetic fiber [F-
1, F-2, F-3] with ethylene-vinyl acetate copolymer hot melt adhesive (manufactured by Hirodyne Industry Co., Ltd., trade name "Hirodine 7514") under processing conditions (temperatures 210 to 2).
After being attached at 30 ° C., a processing speed of 80 m / min, and an attachment amount of 20 g / m ² ), a thermoplastic resin sheet [R1, R2, R
3] was laminated and a molding process was performed. Then, with the combinations of Examples 1 to 5 below, molding conditions and a temperature of 125
Cavity pressure was vacuum-formed at a temperature of 3 seconds by a pressure-air vacuum forming machine manufactured by Semba System Co., Ltd. to obtain a food packaging container (tray) of the present invention. Frozen curry was placed in the obtained tray, thawed and heated in a microwave oven, and the moldability, non-touch feeling, and heat resistance were measured, and the results are shown in Table 1. As a result of Table 1, the food packaging container of the present invention had good moldability, non-touch feeling, and heat resistance.

(Comparative Examples 6 to 8) Using the thermoplastic resin sheets [R1, R2, R3] used in Example 1, pressure-air vacuum forming was carried out in the same manner as in Examples 1 to 5 to obtain food packaging containers. It was The obtained container was measured for moldability, non-touch feeling, and heat resistance in the same manner as in Example 1, and the results are shown in Table 1. As a result of Table 1, the container was a non-tactile object which is the object of the present invention.

[0029]

[Table 1]

[0030]

As described above, since a composite sheet of a specific non-woven fabric and a thermoplastic resin sheet is used as a base material, it has excellent secondary thermoformability and is a frozen food that is thawed and heated, a cup ramen that pours hot water, and an instant soup. A non-contact, easy-to-hold food packaging container such as a hamburger, hot dog, okonomiyaki, miso soup, and a hot food / beverage container such as coffee is provided.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Oi 73 Kanda Nerobecho, Chiyoda-ku, Tokyo Within China Pall Sales Co., Ltd. In the company

Claims (7)

[Claims] 1. A heat-resistant thermoplastic resin sheet having an average apparent specific gravity of 0.01 to 0.4 g / cm ³ and a temperature of 120 ° C. of 2
A container for food packaging, which is a container integrally formed by laminating and joining a synthetic fiber non-woven fabric having 0% intermediate stress of 5 kg / 5 cm or less, wherein the non-woven fabric forms at least the outer layer of the container. 2. The food packaging container according to claim 1, wherein the synthetic fiber nonwoven fabric is composed of hydrophobic synthetic fibers. 3. The synthetic fiber nonwoven fabric comprises crimped fibers,
The food packaging container according to claim 1 or 2, which is a polypropylene long-fiber non-woven fabric having a partially thermocompression bonded portion. 4. The heat resistant temperature of the thermoplastic resin sheet is 60.
The food packaging container according to claim 1, which has a temperature of not less than ° C. 5. The food packaging container according to claim 1, wherein the thermoplastic resin sheet is non-foamed. 6. The food packaging container according to claim 5, wherein the thermoplastic resin sheet is polypropylene, polypropylene containing filler, or polyester. 7. A food packaging container according to any one of claims 1 to 6, which is suitable for thawing and / or heating food.