JP5159538B2 - Vacuum packaging method - Google Patents

Description

In the pressure-resistant chamber, the tray and the material to be packaged are stretched while the heated cover film is stretched with an atmospheric pressure that is reduced to the pressure-resistant chamber after the surroundings of the tray containing the material to be packaged are changed to a vacuum state. It is related with the vacuum packaging method of the foodstuff formed by pressing on the upper surface.

The above-described pressure-resistant chamber is disclosed in Patent Document 1 below, for example. According to this document, the pressure-resistant chamber is composed of a lower box that accommodates the tray inside and an upper box that arranges a hot plate inside. When the upper and lower boxes are brought into close contact with each other so as to sandwich the cover film, a tray arrangement space is formed in the lower box and a hot platen arrangement space is formed in the upper box across the cover film. When the air in the two arrangement spaces is simultaneously sucked with a vacuum pump to be evacuated, and then the atmospheric pressure is applied to the heat plate arrangement space in the upper box, the cover film heated by the heat plate is stretched, It adheres along the tray and the object to be packaged accommodated in the tray, and seals the object to be packaged . In this way, a vacuum package with good storage stability is formed, and the package to be packaged as food can be cooked by heating the vacuum package in a microwave oven.

When cooking an object to be packaged with a microwave oven, steam ejected from the object to be packaged is ejected from a vent hole intentionally formed between the tray and the cover film as shown in Patent Document 2, It is a mechanism to prevent the cover film from bursting. But since the vent hole is a problem that external dust from entering into the tray, Patent Document sealed in 3 chance holes corresponding to the vent holes in the temperature-sensitive glue, steam heat ejected from the packaged articles in by melt-the glue discloses that opening the gap hole. However, since the properties of the processed and manufactured paste are uneven, there is a problem that it does not always melt at the set temperature. That is, if the gap is opened before the set temperature, there is a problem that the object to be packaged is simmered due to insufficient pressure inside the tray, and when the set temperature is exceeded, the cover film is ruptured due to excessive pressure and the object to be packaged is scattered.

The tray package that contains air therein has a characteristic of opening the cover film with the expansion pressure of both the air and the moisture contained in the food when it is cooked in a microwave oven . In the case of a vacuum package, only the vapor pressure evaporating from the food acts as the opening pressure for the cover film, so that the cover film is partially sealed while storing sufficient vapor pressure inside the tray to prevent food from being cooked. However, it is difficult to make adjustments to prevent the cover film from bursting by opening it with steam pressure. Plastisol click made trays, using the film as a sealing material, but will be sealed by heating sealing the two, premature weld portion dropped part of the temperature of the sealing hot plates pull the steam Even if it is formed on a tray package , the heat of the hot platen itself moves with the sealing material and tends to equalize the entire hot platen, the temperature of the immature welded portion changes, and the immature welded portion is opened by vapor pressure. There is a problem that the timing of these changes gradually.

Japanese Patent Laid-Open No. 46-1491 JP-A-6-171611 JP 11-89715 A

The present invention, in order to solve the above problems, in the pressure-resistant chamber, whereas the action of vacuum around the plastisol click made of trays holding food, is heated and softened to cover film with a first heating platen A method of forming a vacuum package by pressing the softened cover film against the tray and the upper surface of the food with atmospheric pressure that is then reduced into the pressure-resistant chamber, the temperature of the first hot platen Is set to the melting resistance limit value of the tray, and before the atmospheric pressure is reduced in the pressure-resistant chamber, the melt layer of the cover film is melted with the first hot plate while the molten sealant layer is A first step of bonding the cover film to the flange of the tray by a first heating plate that applies pressure that can be pushed out of the peripheral flange region of While the flange of the tray being fed is supported from below with a sealing stand, the melting resistance limit of the tray of the second hot platen in which the flange and the cover film adhered to the flange are partly stolen. It comprises a temperature exceeding the value and a second step of clamping at a pressure lower than the pressure of the first hot platen.

In the first step of bonding the cover film to the tray flange, setting the temperature of the first heating plate to withstand the melting limit of the tray, and the withstand molten limit of the tray and the plastisol Tsu constituting the tray It intends saying the temperature numerical value immediately before the front surface of the click material begins to melt. When the pressing force of the first hot platen against the cover film is increased, the temperature acting on the flange of the tray and the sealant layer is increased by the pressure. Due to this temperature rise and the pressing force of the first hot platen, the molten sealant layer is crushed between the flange of the tray and the cover film, and the pressure pushes excess of the crushed adhesive material out of the flange. . And between the nip pressure time is, plastisol click material constituting the tray when it reaches the resistance melting limits for melting, to stop the clamping pressure by the first heating plate. As a result, the tray is in an unmelted state at this point, and the sealant layer in the cover film adheres to the tray with a relatively gentle force.

In the first process area described above, the tray with the cover film adhered thereto is sent to the sealing table in the rear area, and the flange of the tray is supported from below by the sealing table. And the said flange and the cover film closely_contact | adhered to it are pinched and heated by the 2nd heating plate | board provided with a part of a notch. In this case, the temperature of the second heating plate will exceed the withstand melting limit of the tray. Their by to clamping pressure of the smaller second heating plate as compared to the first heating plate of the clamping pressure in the first step, welding the cover film to the tray. In this case, the adhesive force between the tray flange and the cover film is determined by the clamping pressure of the second hot platen. This adhesion is such that the consumer can easily peel off the cover film from the tray with a relatively small force after the vacuum package is distributed on the market, and the vacuum package is cooked in a microwave oven. The portion of the second heating plate that is not pinched by the notch portion is easily peeled off by the heating vapor pressure generated from the food that is the package.

As already described, in the first step, the first heating plate brought the cover film into close contact with the flange of the tray with a pressure sufficient to push the melted sealant layer out of the peripheral flange region of the tray. The effect obtained from such pressing force is that the thickness of the sealant layer is made uniform by extruding the extra sealant material to the outside, and the adhesive force by the sealant layer is made uniform throughout the area. For this reason, the film peeling resistance at the notch portion is equal to the vapor pressure, and therefore the adhesive force at the notch portion corresponding to the amount of generated steam can be accurately adjusted by adjusting the heating temperature and the pinching pressure.

According to the present invention, the adhesive strength of the notch corresponding to the amount of generated steam can be accurately adjusted by adjusting the heating temperature and the clamping pressure.

In FIG. 2 showing the side of the entire apparatus, the pressure-resistant chamber 10 composed of the upper box 11 and the lower box 12 is provided in the first process area, and the lower sealing base 46 and the upper second heat are provided in the second process area. A board 14 is provided. Roll film 16 which is supported by the transverse horizontal axis 15 also is pulled as a strip-shaped cover film by the winding force of the reel 17, whereas, the plastisol click made of tray 20 accommodating the object to be packaged 19, supplied It is adapted to carry in a pressure chamber 10 of the with the apparatus 18.

In FIG. 3, which is a cross-sectional view with respect to the line of sight, the trays 20 are carried in two rows in the pressure-resistant chamber 10, but in the upper box 11, two left and right first hot plates 21 connected to the upper actuator 22. Is provided. On the other hand, in the lower box 12, a tray receiving base 24 in which two recesses 23 are formed and a support plate 25 that supports the tray 20 carried in the upper region of the both recesses 23 are provided at the upper end of the lifting rod 26. It is arranged in support.

The upper box 11 is suspended and supported by the base material 28 via a coil spring 27, while the lower box 12 moves up and down via a lift bar 29. Accordingly, as shown in FIG. 4, when the pressure-resistant chamber 10 is sealed by pushing up the lower box 12 with the lift bar 29 with respect to the upper box 11, the lower actuator 30 has a structure for retracting the tray support 24 downward.

Figure 5 is an enlarged view of the pressure chamber 10, pedestal 24 arranged inside the lower box 12 supports the tray 20 from the bottom, supporting holding plates 25 seal the flanges 31 lowers the tray 20 base 24 Can be attached to the top. The first heating platen 21 installed in the upper box 11 has an inverted saddle shape having the same contour as the flange 31 and presses the cover film 16 against the flange 31 with the lower power of the upper actuator 22 as already described. Can do. A groove 33 around the flange 31 in the cradle 24 is a receiving groove for the upper cutting blade 34, and the cutting blade 34 is supported on the outer box 11 via a frame frame 35.

When the first hot platen 21 is pulled up by the actuator 22 through the bar 36 and the lower box 12 is pushed up so as to be in close contact with the upper box 11, the air in the upper and lower boxes is sucked by the vacuum pumps. Since the upper box 11 and the frame frame 35 are subjected to the reaction force of the coil spring from the upper region, the cut blade 34 pushes the flexible cover film 16 into the groove 33 when the lower box 12 is further moved upward. Therefore, the first hot platen 21 is lowered by the actuator 22 to press the cover film 16 against the upper surface of the flange 31, and the lower box 12 is pushed up against the reaction force of the upper coil spring to cut around the flange 31. After the cover film 16 is cut by the blade 34, when the atmospheric pressure is reduced in the upper and lower boxes, the cover film 16 heated and softened by the first hot platen 21 is stretched, and the tray 20 and the packaged object 19 inside thereof are stretched. It will be in close contact.

The lower surface of the cover film 16 Ri Contact sealant layer is laminated, sandwiched pressed the flange 31 and the cover film 16 of the tray at a high pressure by the first heating plate 21 to increase the heating temperature by pressure, The pressurization by the first hot platen 21 is stopped with a time limit for the tray 20 to reach the melting resistance limit value. Due to the pressurizing and heating effect of the first hot platen in the above, the sealant layer of the cover film becomes poor in viscosity , and an excess portion of the sealant layer is pushed out. However, as a result of adjusting the pressurization temperature rise by the first hot platen 21 so as not to exceed the melting limit value of the tray 20, the continuous adhesion 51 of the cover film 16 to the flange 31 of the tray 20 as shown in FIG. It can be maintained with weak adhesive strength.

In FIG. 2, the illustration of the means for transporting the vacuum package from the lower box 12 toward the sealing base 46 in the rear area is omitted, but the inside of the base 41 installed in the second process area as shown in FIG. The second support plate 42 lowers the transferred vacuum package 43 and seats the flange 31 portion on the seal base 46.

The second heating platen 45 disposed on the upper side is an inverted saddle type, the seal part 46 at the lower edge thereof has the same contour as the flange 31 of the vacuum package 43, and the seal part 46 is partially cut away and a notch part 47. forming a steal-away portion 47 he this notch to form a non-welded portion in a part of the cover film 16. Second heating plate 45, with a small force than squeezing force by the first heating plate 21 in Figure 5, the flange 31 on the seal base 46 of the lower zone, that push clamping the cover film 16. In this case it was, the second heating plate 45 does not raise the welding effect more than necessary are adjusted clamping pressure.

FIG. 1 is a partial perspective view of the vacuum package body, and shows a state in which the cover film 16 is in close contact with the upper surface of the tray 20 supported by the seal base 46. The adhesive state between the flange portion 31 of the tray and the cover film 16 is a close adhesion with a weak adhesive force such as a mesh pattern 51 including the black portion 50 in the first step. Except for the partial mesh pattern 51, a strong adhesion of black coating 50 is applied to the whole. For this reason, in the case of cooking by a microwave oven, the mesh pattern 51 is easily peeled off naturally by the steam pressure generated from the article to be packaged 19 and the steam is discharged to the outside. . However, it is easy to peel the black 50 portion by hand.

In the electronic cooking of the vacuum packaging body, it is necessary to set the partial peeling of the cover film 16 only with the amount of steam generated from the package, and this prevents food from being cooked in accordance with the amount of generated steam without releasing steam from the tray. Although the strengthening of countermeasures has the problem of causing film rupture, the first hot platen has a pressure sufficient to push the molten sealant layer out of the peripheral flange area of the tray, and the sealant layer is pushed out by extruding excess resin to the outside. Since the adhesive strength of the sealant layer is made uniform throughout the entire area, the adhesive strength of the stealing portion 47 can be accurately adjusted by adjusting the heating temperature and clamping pressure along various vacuum packages with different amounts of generated steam. there is a Ru effect that can be of.

INDUSTRIAL APPLICABILITY The present invention is useful for a vacuum packaging method for manufacturing a tray in which an object to be packaged to be cooked with a microwave oven is packaged.

Cross-sectional perspective view of vacuum package Overall view of the device Cross section of pressure chamber in the first process area Action diagram of the previous figure Expanded cross section of pressure chamber Vacuum package top view Sectional view of the sealing device in the second process area

10 ... Pressure-resistant chamber 11 ... Upper box 12 ... Lower box 14 ... Second heating plate 16 ... Cover film 20 ... Tray 21 ... First heating plate 24 ... Tray tray 31 ... Flange 43 ... Vacuum package 46 Seal stand

Claims (1)

In inside the pressure chamber, while the action of vacuum around the plastisol click made of trays holding food, is heated and softened to cover film with a first heating plate at atmospheric pressure reduced to Then the pressure-resistant chamber A method for forming a vacuum package by pressing the softened cover film against the tray and the upper surface of the food,
The temperature of the first hot platen is set to the melting limit value of the tray, and before the atmospheric pressure is reduced in the pressure resistant chamber, the sealant layer of the cover film is melted with the first hot platen, A first step of bonding the cover film to the flange of the tray by a first hot platen that applies pressure capable of extruding the melted sealant layer out of the peripheral flange region of the tray;
The second hot platen is provided with a notch portion in part for supporting the flange of the tray conveyed from the first process area from below with a sealing stand, while partially supporting the flange and the cover film bonded thereto. A vacuum packaging method comprising a temperature exceeding a melting resistance limit value of the tray and a second step of clamping at a pressure lower than the pressure of the first hot platen.