JPS602982B2 - Method of packaging composite cardboard for fruits, vegetables, and cut flowers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a composite cardboard for fruits, vegetables, and cut flowers, and more specifically, a method for producing a composite cardboard for fruits, vegetables, and cut flowers, in particular, by hot melting a synthetic resin film having water vapor permeability, oxygen and carbon dioxide gas permeability within a specific range, and corrugated cardboard. This invention relates to a method for manufacturing composite corrugated cardboard that is laminated in spots using a mold adhesive.

Cardboard boxes used as packaging containers for fruits and vegetables such as vegetables and fruits or cut flowers are preferable because they are sufficiently protected from physical effects such as transportation, vibration, and impact.

However, since the respiration and evaporation effects of fruits, vegetables, and cut flowers after they are harvested are not taken into account, there are problems with their preservation. The present inventors have discovered that in order to improve the shelf life of fruits, vegetables, and cut flowers, it is necessary to appropriately control the environment within the packaging container, that is, the concentration of oxygen gas, carbon dioxide gas, and humidity, and to achieve this objective. Therefore, a patent application was previously filed for a fruit and vegetable packaging paper container made of a composite paper made by laminating a synthetic resin layer and a paper layer, each of which has permeability of water vapor, oxygen, and carbon dioxide within a specific range (Mochiiso No. 53-93662). However, there are various problems when a composite corrugated board is produced by using the preferred synthetic resin layer disclosed in the above-mentioned patent application, such as a biaxially oriented polystyrene film, and bonding this and a corrugated board sheet with an adhesive.

In other words, there are usually three types of adhesives used for bonding: {A' water-based emulsion type 'o} solvent type W hot melt type; After coating, the material is heated and dried to remove water and solvent by evaporation before being bonded to the corrugated cardboard sheet. In order to perform this bonding process efficiently, high-speed operation is required, and a large amount of drying equipment is required. There must be.
Therefore, it becomes a factor of significant cost increase. In addition, the film is heated and expanded during the drying process, and if it is bonded to cardboard in this state, there is a risk that the composite fabric will warp due to subsequent shrinkage of the film. Furthermore, [o}
In this case, handling of the solvent vapor separated during the drying process is extremely troublesome and gives rise to various difficult problems. In the case of the hot-melt adhesive described above, there is no need for a drying process as in the cases of 'a' and 'o' above, so it is possible to easily operate at high speeds efficiently and reduce manufacturing costs. .

In addition, although the temperature of the part of the film to which the hot melt is applied increases momentarily and locally, the film as a whole hardly causes any thermal tension, so warpage occurs in the composite material as described above. The risk of doing so is much less. In particular, when hot-melt adhesive is applied to the film in spots and in such a way that the ratio of the applied area to the total area of the film, that is, the application rate reaches 60 to 85%, and the adhesive is bonded to the cardboard, the above warping phenomenon is hardly observed. The inventors of the present invention confirmed through many experiments that this would not occur, and immediately applied for a patent (Tsubakibuta 1977-1).
No. 55548). However, the laminating bag hawk disclosed in this application is a device that directly laminates a film coated with a hot melt adhesive in spots on cardboard manufactured using a normal corrugated board machine, and Such film coating and lamination requires the addition of new and complicated equipment to the corrugated board manufacturing equipment, and also creates new problems in adhesive application technology. Therefore, such a coating method is not preferred. Rather, it is preferable to roll a film to which a predetermined amount of adhesive has been applied beforehand, feed this material to a normal corrugated board manufacturing device, and attach it to a normal corrugated board paper. The present invention is a method for manufacturing composite corrugated board made from such Tsurumi dots. An object of the present invention is to provide an efficient and economical method for manufacturing the composite corrugated cardboard, which does not cause warpage and has favorable performance for transporting and storing fruits, vegetables, and cut flowers.

The present invention is based on water vapor permeability (Honeywell formula: Evening/Wednesday, 24
r, 3rd class ○, 90% RH) 45-250 Oxygen permeability (isobaric method: cc/〆, 2 must r, a blood, 30℃) 2000-2
0000, carbon dioxide permeability (Rissey method: cc/〆, 2
4R, ATM, 30°C) 5,000 to 40,000 synthetic resin film, preliminarily coated with hot melt adhesive in spots, and the applied area is 60 to 85% of the film area.
%, and after cooling, it is rolled up into a roll to obtain a raw fabric, and then the coated raw fabric is heat-adhered and laminated to an ordinary corrugated base paper to produce a composite corrugated board. If at least one of the water vapor permeability, oxygen gas and carbon dioxide gas permeability specified in the present invention is outside the range specified above, the storage stability will be poor.
When using a material that satisfies three specific conditions, excellent preservation of fruits, vegetables, and cut flowers can be achieved. Next, Fig. 1 and Fig. As shown.

In the case of FIG. 1, the outer surface of the top liner 1 is entirely covered with two layers: the adhesive layer 2 and the synthetic resin film 3.
There is a temporal difference in the moisture absorption and desorption behavior of water vapor between the upper liner 1 and the lower liner 4 of the original corrugated board.

Therefore, the composite corrugated board as shown in FIG. 1 may warp over time. child. On the other hand, in the case of FIG. 2, the upper liner 5 and the synthetic resin film 6 are laminated in spots with hot melt 7, and a lotus passage space 8 is formed in the darkness between the liner 5 and the synthetic resin film 6. Ru. This passage space 8 alleviates the temporal difference in moisture absorption and desorption behavior of water vapor between the upper liner 5 and the lower liner 9 supported on the upper surface, and has the effect of significantly reducing the occurrence of warpage. When the coating rate of hot melt exceeds 85%, the above-mentioned reduction effect almost disappears. Moreover, it has been found through experiments that if the coating rate is less than 60%, the adhesive strength between the top liner 5 and the synthetic resin film 6 decreases, making it difficult to achieve a strength that can withstand practical use. These results are shown in Table 1. First description: The measurement of the sled is shown in Figure 3, in particular 600 plates x 60 plates.
Place the sample cut into a zero plate on a flat surface, measure the heights e, f, g, and h from the floor at the four corners, and find the average value.

From Table 1, it can be seen that a composite corrugated board with less warpage can be obtained when the hot-melt adhesive peaks are applied and laminated so that the applied area is 60 to 85% of the total area of the film.

Next, the method of the present invention will be explained in detail with reference to the drawings.

FIG. 4 shows a specific example of an apparatus for applying a hot melt adhesive to 60 to 85% of the area of one side of a film.

Reference numeral 21 denotes a raw roll, and a synthetic resin film 22 to be unwound passes through guide rolls 23 and 24, and then a hot-melt type adhesive coating device A applies adhesive in spots on one side of the film.

The coating device A includes a melting bath 25, a lifting roll 26, an engraving roll 27, a doctor knife 28, and a backup roll 29. The adhesive 30 is melted and maintained in the melting bath 25 at a predetermined temperature, for example, 16yo. Kumiage roll 26
As shown in the figure, the lower part is plunged into the hot melt 30, and it is rotated in the direction of the arrow to draw up the adhesive 30 and supply the adhesive to the adjacent engraving roll 27. The central axis of the pick-up roll 26 has a fine adjustment mechanism that can move up and down, and adjusts the contact gap with the upper engraving roll 27 to adjust the amount of adhesive supplied. A large number of recessed holes 31 are engraved on the outer peripheral surface of the engraving roll 27, as shown in FIG. When the number of recessed holes 31 is n, the surface area thereof is s, and the total surface area of the engraving roll 27 excluding the smooth parts at both ends is S, then s×n/S=0.
The number n of the recessed holes 31 and the surface area s are determined so as to be 6 to 0.85, and the engraving is performed. sculpture. Heater 3 is attached to the center axis of the roll 27.
2 can also be provided to adjust the temperature as appropriate. A doctor knife 28 is provided on the engraving roll 20 to sufficiently scrape off adhesive adhered to the smooth surface other than the recessed holes 31. In this way, as shown in FIG. 6, the recessed hole 31 becomes filled with hot melt 33 and rotates in the direction of the arrow, and its upper end surface is pressed against the lower surface of the film 14 by the backup roll 29 with appropriate pressure. It transfers adhesive in spots. The film 38 to which the adhesive has been transferred is cooled by a cooling roll 39, passed through a guide roll 40, and then wound onto a winding roll 41. The hot melt that can be used in the present invention needs to have the ability to not block when wound up into a roll with the above-mentioned winding roll, and furthermore, as described later, when it is heated and bonded to corrugated paperboard, it is necessary to have the property of not blocking the film. It is necessary that the temperature is low enough to adhere to the corrugated paperboard at a temperature lower than the deformation temperature. Specific examples of adhesives with such performance include Cemediso ■A77 Nyukyo and Hirodine Kogyo ■4610.

Next, we will explain the method of laminating a synthetic resin film onto a corrugated paperboard using a raw fabric (hereinafter referred to as raw fabric B) with adhesive applied in spots on one side of the synthetic resin film as described above. . FIG. 7 shows a specific example of a bonding device.

In FIG. 7, 110 is a single-sided corrugated board obtained by step-molding a core using a single facer part of a corrugator, applying an adhesive to the core, and bonding it with a liner. 1
11 is a gluing machine for gluing the bottom surface of the single-sided corrugated board 110.

112 is a lower liner supplied from the double facer section of the corrugator.

Part a is a hot plate for bonding the single-sided corrugated board 110 and the bottom liner 112 together. The b section is a cooling section that cools and dehydrates the heated cardboard for bonding while pressing the cardboard to prevent warping. C, , C2 are textile canvas belts that pass through the heating plate and the cooling section, C, is the upper belt, and C2 is the lower belt. Section D is a device for pasting the original fabric B onto the upper surface of the corrugated cardboard base paper 113 that passes through the heating plate a and the cooling section b and is carried out by the canvas belt C2. The D section consists of a feeding device for pork cloth B, a guide roll 1 14, a heating roll 1 15, and a heating pressure roll 1 16. The film that is unwound from the original film B is guided by the guide roll 114.
The corrugated cardboard base paper 1 is heated appropriately by the heating roll 116 and is carried out by the above-mentioned canvas belts C, C2.
The composite corrugated paperboard 117 is formed by pressing onto the upper surface of the corrugated paperboard 113 with a heated pressing roll 116 installed on the upper surface of the corrugated paperboard 113 . As mentioned above, the film is adhered to the top surface of the top liner of the corrugated board with a hot melt adhesive in spots with a coating rate of 60-85%, and then a slitter scorer is used in the same way as a normal corrugator. After passing through a cut-off machine, delivery, and auto stacker, the product goes through a box-making process to become a packaging container.

In the present invention, the synthetic resin film to be laminated to the corrugated board is a biaxially oriented polystyrene film (for example, Asahi Dow ■ Stylo Film ■TH) with a thickness of 15 to 80 R, which is within the above air permeability and moisture permeability range. preferable.

Besides polystyrene, polystyrene copolymers (such as acrylonitrile) or mixtures of polystyrene and polystyrene copolymers, as well as ethylene-vinyl acetate copolymers can also be used.

・In addition, it is not limited to the above resins, but can be made by appropriately combining films with appropriate air permeability and water vapor permeability, and by appropriately selecting the thickness of each film to achieve the desired air permeability and water vapor permeability. It is also possible to laminate it to corrugated paperboard using the same material. As explained above, according to the method of the present invention, a synthetic resin film having a transmittance in a specific range in advance. A hot-melt adhesive that can be heat-bonded at a temperature lower than the heat deformation temperature of the film and does not block when the film is rolled up is applied to one side of the film in a predetermined manner. No blocking phenomenon occurs when rolled into a roll due to the hot melt adhesive. Further, by heat-bonding this roll-shaped film to corrugated paperboard, it is possible to efficiently and economically produce a composite corrugated board that has favorable performance for transporting and storing fruits, vegetables, and flowers. Moreover, from this composite cardboard, containers with excellent storage stability can be easily manufactured, taking into consideration the water evaporation effect and respiration effect of fruits, vegetables, and cut flowers, and can be used in the same way as ordinary cardboard boxes. Furthermore, according to the method of the present invention, the warping of the composite corrugated cardboard box that tends to occur during film lamination is reduced, so that it is possible to prevent the strength of the corrugated cardboard box from decreasing due to moisture absorption that occurs during transportation and storage.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional diagram of a case where an adhesive layer is provided on the entire upper surface of the box cardboard and a synthetic resin film is laminated thereon, and Fig. 2 is a schematic cross-sectional diagram of the case where a synthetic resin film is bonded to the top surface of the box cardboard. figure,
Figure 3 is an explanatory diagram of the measurement method for warping, Figure 4 is a side diagram of an example of an apparatus for applying hot melt adhesive to one side of a film, Figure 5 is a front view of the engraving roll, and Figure 6 is a diagram of the method for measuring warpage. FIG. 5 is a diagram showing a state in which the recessed hole of the engraved roll is filled with a hot-melt adhesive, and FIG. 7 is a side view of an example of an apparatus suitable for heating and bonding the composite corrugated board of the present invention. 6, 9... Corrugated cardboard liner, 3, 6, 22...
...Synthetic resin film, 7, 30, 33. ．．・．．
．．・Hozamelt type adhesive, 8...Communication space,
A... Adhesive applicator, 31... Recessed hole, B...
Original fabric, C, Ri C2, C3...Canvas belt, 1 1
6... Heat pressure bonding roll, 117... Composite corrugated board. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1 Water vapor permeability (Honeywell formula: g/m^2, 24h
r, 38℃, 90%RH) 45-250, oxygen permeability (
Isobaric method: cc/m^2, 24hr, atm, 30℃)2
000-20000, carbon dioxide permeability (Litsy method: c
c/m^2, 24hr, atm, 30℃) 5000~4
A hot melt adhesive that can be heat-bonded at a temperature lower than the heat deformation temperature of the film and that does not cause blocking when the film is rolled up is applied to one side of a 0000 synthetic resin film in spots and over the whole surface. Vegetables and fruits characterized by applying heat so that the coating area is 60 to 85% of the film, and after cooling, winding it up into a roll to obtain a raw film, and then heat-adhering the coated raw film to ordinary corrugated paperboard.・Method for manufacturing composite cardboard for cut flowers. 2. The method for producing a composite corrugated board for fruits, vegetables, and cut flowers according to claim 1, wherein the synthetic resin film is made of polystyrene. 3. The method for producing a composite corrugated board for fruits, vegetables, and cut flowers according to claim 1, wherein the synthetic resin film is made of a polystyrene copolymer. 4. The method for producing a composite corrugated board for fruits, vegetables, and cut flowers according to claim 1, wherein the synthetic resin film is made of a mixture of polystyrene and polystyrene copolymer.