JPH0244716Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a packaging form for meat buns, shumai, etc., which are steamed and eaten using steam. Steamed foods such as red bean paste buns, meat buns, and shyuumai are usually sold as frozen foods at retail stores such as department stores and supermarkets. teeth
They are lined up in HIPS resin trays and then sold in boxes. The customer uses a steamer such as a steamer basket at home, places a damp cloth (Japanese tenugui) on top of the steamer's bamboo basket, arranges the steamed buns or shumai on top of this, puts the lid on, and then heats the steamer. Steam is generated and the steam is applied from below the food to steam it and eat it. For these foods that are prepared on the spot, it is time-consuming to take out the steamer, use a dish towel, and clean up the used utensils. If you can cook food by throwing the bag into boiling water like a Kutsukudo-in pouch, and then throw the bag away after opening and eating, you can save some time. The purpose of this invention was to enable a closed-in pouch type of use for steamed foods, and its characteristics are that it can be used as a packaging material for these foods, allowing water vapor to pass through it, but not allowing water to pass through. The point is that a biaxially stretched porous polyethylene film is used. That is, the present invention is a steamed food such as meat buns, red bean buns, shumai, sekihan, etc. that are sealed in a water-resistant bag and are steamed and eaten, and at least 20% or more of the area of the material of the bag is as follows: Water vapor that satisfies conditions (a) to (d) passes through, but water does not pass through 2
The present invention provides a steamed food characterized by being dominated by an axially stretched porous polyethylene film. (a) Moisture permeability measured by JIS Z-0208 is 1000~
25000g/ ^m2・24hr. (b) The thickness of the film is 20 to 80 microns. (c) The film has many fine voids with a pore size of 0.1 to 5 microns inside. (d) The stretching ratio in the longitudinal direction and the transverse direction is 2 each.
~4 times. Hereinafter, the present invention will be explained in more detail with reference to the drawings. FIG. 1 is a perspective view of the red bean paste bun 2 sealed in the bag 1, and FIG. 2 is a sectional view thereof. In the figure,
3 is glassine paper, and 4 is a heat-welded portion produced when forming the bag 1. The bag 1 needs to be made of a porous polyethylene film that allows water vapor to pass through but not water, so that at least 20% of its area is used to guide water vapor into the bag. This porous film has a melt flow rate of 0.01 to 3 g/10 as measured by JIS K-6760, for example.
65 to 230 parts by weight of inorganic fine powder with a particle size of 0.1 to 15μ, preferably 0.3 to 2μ is mixed into 100 parts by weight of polyethylene with a melting point of 123 to 136°C. The resulting composition was melt-extruded to obtain a cylindrical film, which was then melt-extruded using a mandrel.
At a temperature lower than the melting point of the polyethylene, 2 to 4 times, preferably 2.3 to 3.8 times, in the machine direction and the transverse direction, respectively.
Manufactured by double stretching (JP-A-57-
129722, JP-A-57-129723), JIS Z-
The moisture permeability measured with 208 is 1000 to 25000g/ ^m2 .
24hr, preferably 5000~10000g/ ^m2・24hr,
It is a porous film with a wall thickness of 20 to 80 microns and has a large number of fine voids with pore diameters of 0.1 to 5 microns, which are produced by stretching, with inorganic fine powder as the core inside the sheet. This porous film has a pressure of 2 Kg/cm ² and a temperature of 25
The water permeability measured at °C is 0% (JIS L-1079). The air permeability of this porous film measured according to JIS P-8117 is 25 to 500 seconds 100 c.c., and the apparent density is 0.4 to 0.8.
g/cc. The number of stretching axes of this porous polyethylene film is two. If it is uniaxial, the film tends to tear in parallel to the direction of the stretching axis due to external stress, so cutting,
It becomes difficult to perform tasks such as filling food. By changing the stretching ratio, stretching temperature, and amount of inorganic fine powder, the void diameter, air permeability, moisture permeability, film thickness, and flexibility can be adjusted. When heating and humidifying food with boiling water in an open pot, the moisture permeability measured according to JIS Z-0208 must be 1000 g/m in order for enough water vapor to pass through the film material to steam the food. ^2. Must be 24 hours or more. On the other hand, the moisture permeability is 25000g/ ^m2・24hr
If you use a high film that exceeds
When the bag is torn open and the manju is eaten, condensed water often falls on the manju, reducing appetite. The thickness of the film is determined to be 20 to 80 microns due to cost considerations, ease of bag making, and flexibility limitations. This porous film allows water vapor to pass through and makes it easy to tear to open the bag.
There are many fine voids inside the film. The amount of voids is determined by the apparent density of the porous film ρ ₁
The stretching temperature, stretching ratio, and amount of inorganic fine powder are adjusted so that the porosity P derived from the following equation is 20 to 80% from the density ρ ₀ of the polyethylene resin composition for forming a porous film before stretching. Establish. P=ρ ₀ −ρ ₁ /ρ ₀ ×100 (%) The stretching ratio is at least 2 times or more in order to prevent the film from being tied in. In addition, in order to make the porous film easier to tear by hand, it should be 4 times or less. When the stretching ratio exceeds 4, a greater force is required to tear the porous film, and the film often contracts significantly during steaming, causing the bag to deform. This biaxially oriented polyethylene porous film must occupy at least 20% of the area of the bag.
The entire material of the bag may be this porous polyethylene film. However, when the contents inside the bag are required to be visible from the outside, as shown in FIG. The film material 1b can be made of transparent polypropylene or translucent high-density polyethylene (these films 1b are not stretched). In the figure, numeral 5 is a rice cake, and 6 is a tray made of high-impact polystyrene (HIPS), and the bottom of this tray is perforated with holes of 2 to 5 mm to facilitate the permeation of water vapor. In this invention, the steamed foods filled in the bag include meat buns, red bean paste buns, sake buns,
Examples include manju such as miso manju, shyu mai, and sekihan. If the packaging form of the present invention is used, there is no need to use a steamer such as a steamer basket, and the food inside the bag can be dropped into boiling water in a pot, covered with a lid, and steamed, allowing the water vapor to pass through the porous film. It has the advantage of being steamable and easy to cook like conventional cooked-in pouches. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example of manufacturing porous film 1 High density polyethylene (MFR=0.02g/10min,
A heat stabilizer (2 ^, 6-di-t-butyl-p-cresol), per 100 parts by weight of calcium carbonate,
1.0 parts by weight of a dispersant (oleic acid) was stirred in a super mixer for 5 minutes, extruded into a strand at 265°C from a twin-screw extruder, and then cut into pellets. The pellets obtained by the above method were
After extrusion at 240℃ from a 4-line spiral die with an annular die lip diameter of 75φ and lip distance of 1 mm attached to an extruder with 50φ and L/D=25, a diameter of 100φ with water at 5℃ circulating inside. The unstretched tubular film with a thickness of 120 μm was taken off at a rate of 2.1 m/min. Subsequently, after heating to 125℃ with a preheating mandrel with a diameter of 98φ connected below the cooling mandrel,
The diameter of the end face directly connected to the preheating mandrel is 98φ,
The diameter of the other end face is 250mm, and its cone angle is
Using a truncated conical stretching mandrel with a 90° surface coated with Teflon, the material was stretched 2.5 times in the transverse direction (TD) at 125°C while being stretched in the machine direction (MD).
A biaxially stretched film having a thickness of approximately 60 μm was obtained by stretching 2.5 times. Table 1 shows the physical properties of this biaxially stretched film. Example 2 In Example 1, the screw rotation speed of the extruder was changed to produce an unstretched tubular film with a wall thickness of 125 microns.

[Table] * Blow-up Precision Examples 1 to 3, Comparative Examples 1 to 2 After cutting the cylindrical films obtained in Production Examples 1 to 5 above, the two films were stacked, heat-sealed on three sides, and cut lengthwise. A bag measuring 16 cm long and 16 cm wide with one end open was obtained. This bag was filled with meat buns (temperature: 5° C.) with a diameter of about 9 cm and a height of about 4 cm, and one open end was heat-sealed to seal the buns inside the bag. This was poured into boiling water in a pot, covered and heated for 2 minutes. The pressure inside the pot was 1 atm. After removing the lid, he used chopsticks to throw the bag out of the pot, tore the bag open with his hands, and ate the meat bun inside the bag. Table 2 shows the presence or absence of deformation of the bag taken out of the pot, the ease with which the bag was torn, and the degree of steaming of the meat bun. Example 4 A bag was prepared in the same manner as in Example 1, except that the porous polyethylene film obtained in Example 3 was used as a material on one side, and the polypropylene film of Example 4 was used as a material on the other side, which was thermally bonded at 230°C. I steamed the meat buns and ate them. Table 2 shows the presence or absence of deformation of the bag taken out of the pot, the ease with which the bag was torn, and the degree of steaming of the meat bun.

【table】

*The air inside the bag is expanding,
The bag was torn open.
** The skin on the surface of the meat bun is heated and hot, but the center filling is hot.
The portions were not heated and were cold.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a steamed food according to an embodiment of the present invention seen from the outside, Fig. 2 is a sectional view thereof, and Fig. 3
The figure is a sectional view of a steamed food showing another example. In the figure, 1 is a bag, 1a is a biaxially stretched polyethylene porous film, and 2 or 5 is a food that is steamed and eaten.

Claims (1)

[Scope of claim for utility model registration] Steamed foods such as meat buns, red bean paste buns, shumai, sekihan, etc. that are sealed in a water-resistant bag and are eaten by steaming, which account for at least 20% of the area of the material of the bag.
A steamed food characterized in that the above is occupied by a biaxially stretched porous polyethylene film that satisfies the following conditions (a) to (d) and is permeable to water vapor but not permeable to water. (a) Moisture permeability measured by JIS Z-0208 is 1000~
25000g/ ^m2・24hr. (b) The thickness of the film is 20 to 80 microns. (c) The film has many fine voids with a pore size of 0.1 to 5 microns inside. (d) The stretching ratio in the longitudinal and transverse directions is 2 each.
~4 times.