JP2005067629A - Corrugated box and packaging method for maintaining freshness of vegetables/fruits - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a corrugated box for maintaining the freshness of vegetables/fruits, in which the vegetables/fruits are put and packaged to be transported by a truck or the like to a destination and which can be easily disaggregated and recycled, and a method for maintaining the freshness of vegetables/fruits using the corrugated box. <P>SOLUTION: A liner is formed on the inner/outer surfaces of the corrugated board. The liner is a moistureproofing liner formed by coating a liner base paper with a coating layer, which is made of a moistureproofing coating material, which contains a granular pigment having an aspect ratio of 3 or less and an average grain diameter of 5-15 μm, a flake pigment having an aspect ratio of 5 or more, and a synthetic resin emulsion. The moistureproofing liner shows a moisture permeability (JIS Z 0208) of 300 g/m<SP>2</SP>per 24 hours or less, and a Cobb water-absorbing capacity (JIS P 8140) of 5 g/m<SP>2</SP>per 2 minutes. According to the packaging method for maintaining the freshness of vegetables/fruits, the harvested vegetables/fruits are packaged in the corrugated box and are precooled, and are maintained under a temperature of 10°C or lower. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is a fruit and vegetables freshness-keeping cardboard box in which fruits and vegetables are packaged and transported to a destination or the like by a truck or the like. The present invention is also a freshness-keeping packaging method using the fruit and vegetable freshness-keeping cardboard box.

Conventionally, JP-A-2003-3394 (Patent Document 1) and the like exist as a corrugated cardboard sheet having moisture resistance and being easily disintegrated and recyclable.
The above technology is a moisture-proof coating containing a synthetic resin, a flat pigment having an aspect ratio of 5 or more, and a granular pigment having an aspect ratio of 3 or less and an average particle diameter of 5 to 15 μm as a liner on at least one side of the corrugated cardboard sheet. A moisture-proof liner having a layer is used.
The cardboard box manufactured using such a corrugated cardboard sheet has a water vapor barrier property, and the moisture-proof liner has an effect of suppressing the transpiration of fruits and vegetables when packaging and transporting the fruits and vegetables. Can be used as a box.
JP 2003-3394 A

However, when a corrugated sheet as described above is manufactured as a corrugated cardboard box, the moisture-proof layer is inferior in adhesion, bonding, and printability. It has been common to use a moisture-proof corrugated cardboard sheet so that a moisture-proof layer is formed only on the inner surface side of the cardboard.
However, if the fruits and vegetables are packed in such a moisture-proof cardboard box and then pre-cooled and transported, dew condensation water is formed on the outer surface of the cardboard box due to the temperature difference between the outside air and the pre-cooled fruits and vegetables and the corrugated cardboard box in which they are packed. Arise. When the outer surface liner of the cardboard box is a general liner that does not have moisture resistance, the generated condensed water penetrates from the outer surface liner to the bonding surface side of the inner core and the inner liner and the inner core. As a result, the moisture content of the corrugated cardboard sheet increased, and the corrugated cardboard sheet strength and the cardboard box strength decreased. Furthermore, the problem that the heat insulation cold insulation property of a cardboard box fell occurred.

Contrary to the above, when a moisture-proof layer is provided only on the outer side of the cardboard box and a general liner is used on the inner side, the penetration of condensed water on the outer side of the cardboard box can be prevented by the moisture-proof layer. The permeated water permeates from the liner on the inner surface of the box to the inner core and the bonding surface side between the outer liner and the inner core. As a result, the moisture content of the corrugated cardboard sheet increases, so that the corrugated cardboard sheet strength and the corrugated cardboard box strength decrease. Moreover, the problem that the heat insulation cold preservation property of a cardboard box fell occurred. This is a problem particularly in leafy vegetables that generate a large amount of transpiration water.
In addition, when moisture-proof layers are provided on both the inside and outside of the cardboard box, the adhesive strength is not sufficient because both sides are moisture-proof and low in water absorption during box making of the cardboard box. Therefore, the box compression strength was not sufficient.
Furthermore, when printing is performed using a commonly used aqueous flexographic ink on the outer surface of the cardboard box, printing is difficult due to the low water absorption of the moisture-proof layer. In particular, when two or more colors were printed in an overlapping manner, the printed surface was contaminated.

In order to solve the above problems, the present invention takes the following means.
That is, according to the first aspect of the present invention, a liner that forms the inner and outer surfaces of a cardboard box is a flat plate on a liner base paper having an aspect ratio of 3 or less and an average particle diameter of 5 to 15 μm, and an aspect ratio of 5 or more. Moisture-proof liner in which a coating layer is formed of a moisture-proof paint containing a pigment and a synthetic resin emulsion, and the moisture permeability of the moisture-proof liner (JIS Z 0208) is 300 g / m ² · 24 h or less, degrees (JIS P 8140) is vegetables and fruits freshness cardboard box is 5g / m ² · ² minutes or less.

  A second aspect of the present invention is the fruit and vegetable freshness-preserving cardboard box according to the first aspect of the present invention, wherein the outer surface of the cardboard box uses two or more water-based flexographic inks and the inks of the respective colors are printed without overlapping each other. is there.

  The third aspect of the present invention is the freshness of fruits and vegetables according to any one of the first and second aspects of the present invention, wherein the paste margin part is bonded with a synthetic resin adhesive at the time of boxing of the cardboard box and then left to stand under pressure for 1 hour or more. It is a holding cardboard box.

  A fourth aspect of the present invention is a freshness-keeping packaging method in which the harvested fruits and vegetables are packaged in a cardboard box and then pre-cooled. This is a packaging method for maintaining freshness of fruits and vegetables held at 10 ° C. or lower.

  5th of this invention is the fruit and vegetables freshness maintenance packaging method of 4th this invention which cools with the vacuum precooling method.

  According to the present invention, a corrugated cardboard box that can be re-disaggregated after use, when packaging fruits and vegetables and used for cold transport, prevents strength reduction due to condensation, adhesive strength is sufficient, box compression strength does not decrease, surface In addition, it is possible to obtain a suitable freshness-keeping cardboard box and a freshness-keeping packaging method for fruits and vegetables.

The present invention will be specifically described below.
In the present invention, the particulate pigment used in the moisture-proof paint for forming the inner and outer coating layers of the corrugated cardboard box for maintaining freshness of fruits and vegetables refers to those having an aspect ratio of 3 or less.
The granular pigment having an aspect ratio of 3 or less used in the present invention is roughened by exposing the pigment to the surface of the coating layer by blending it in a moisture-proof coating, thereby reducing the contact area between the surface of the coating layer and the surface of the calender roll. This prevents the moisture-proof paint from sticking to the calendar surface.

  The aspect ratio range of the particulate pigment is 3 to 1, more preferably 2 to 1, and it is more desirable to have a shape as close to 1 as possible. When the aspect ratio exceeds 3, there is a problem that the pigment is not exposed on the coating surface of the moisture proof layer, and the adhesion preventing effect of the moisture proof layer cannot be obtained.

The average particle size of the granular pigment needs to be in the range of 5 to 15 μm. When the average particle diameter is less than 5 μm, the particulate pigment is not sufficiently exposed on the coated surface, and the contact area between the coated surface and the machine calendar portion becomes large, so that an anti-adhesion effect cannot be obtained.
On the other hand, when the thickness exceeds 15 μm, the surface property of the coating surface of the moisture-proof layer is deteriorated and the moisture-proof property is lowered.

Moreover, it is desirable that the granular pigment is blended in an amount of 3 to 15% by mass with respect to the total solid content in the paint. When the amount is less than 3% by mass, the amount of the particulate pigment is too small, so that the anti-adhesion effect in the machine calendar may not be sufficiently obtained. Moreover, when it exceeds 15 mass%, the surface property of the coating layer of a moisture-proof layer may deteriorate, and there exists a possibility that moisture-proof property may fall.
In addition, since a granular pigment protects a coating surface from the heat pressure of a machine calendar, it is desirable for it to have heat resistance in itself.

  Specifically, calcium carbonate, heavy calcium carbonate, silica, clay or the like can be used as such a granular pigment. In particular, heavy calcium carbonate is preferably used.

  In addition, the average particle diameter in this invention is measured by the laser diffraction method. The aspect ratio is a value obtained by dividing the average particle diameter by the average thickness of the plate-like particles. The particle diameter measurement by the laser diffraction method can be measured by “Laser diffraction particle size distribution analyzer SALD2000J” manufactured by Shimadzu Corporation.

Next, the flat pigment used in the moisture-proof coating layer of the present invention refers to those having an aspect ratio of 5 or more, and those having an aspect ratio of 10 or more are more preferably used.
Since the pigment having an aspect ratio of less than 5 has insufficient flatness, it cannot be oriented in parallel to the coated surface during coating, so that excellent moisture resistance cannot be obtained. As the aspect ratio is larger, the number of layers in the coating layer of the flat pigment is increased, so that high moisture proof performance is exhibited.

Specific examples of flat pigments include phyllosilicate compounds (layered silicate compounds having a layered structure). Those belonging to the phyllosilicate compounds are plate-like or flaky and have clear cleavage, mica, pyrophyllite, talc, chlorite, septe chlorite, serpentine, stilpnolane There are clay minerals. Of these, mica and talc are preferable. The mica family includes muscovite (mascobite), sericite (sericite), phlogopite (flocopite), biotite (biotite), fluorine phlogopite (artificial mica), red mica, soda mica, vanadine mica, illite, Chin mica, paragonite, brittle mica and so on.
Of these phyllosilicate compounds, muscovite, phlogopite, or sericite is more preferable from the viewpoint of particle size, aspect ratio, and the like.
Furthermore, synthetic mica called a swellable mica mineral or synthetic smectite can also be used.

The average particle diameter of the tabular pigment suitably used in the present invention is 1 to 100 μm, more preferably 5 to 50 μm.
In the case of a flat pigment having an average particle diameter of less than 5 μm, the orientation of the flat pigment in the coating layer is difficult to be parallel to the support, and when it is 50 μm or more, a part of the flat pigment protrudes from the coating layer. In addition, as the thickness of the flat pigment becomes about several μm, the number of layers in the coated layer of the oriented flat pigment decreases, so that the effect of improving the moisture proof performance decreases.

  The synthetic resin emulsion used in the moisture-proof coating of the present invention includes a styrene-butadiene copolymer, a styrene-acrylic copolymer, a methacrylate-butadiene copolymer, an acrylonitrile-butadiene copolymer, and an acrylic copolymer. , Polyester copolymers, polyurethane copolymers, and the like. Of these, styrene-butadiene copolymers are preferred.

The styrene-butadiene copolymer (SBR) is a copolymer mainly composed of styrene and 1,3-butadiene, but may be a copolymer of other monomers copolymerizable with these. Other monomers include aromatic vinyl compounds such as α-methylstyrene, vinyltoluene, pt-butylstyrene, chlorostyrene, isoprene, 2,3 dimethyl-1,3-butadiene, and 1,3-pentadiene. And conjugated diene compounds.
The glass transition temperature (Tg), particle diameter, gel fraction (mass of insoluble portion when tetrahydrofuran is used as a solvent), molecular weight, etc. of the synthetic resin are not particularly limited, but generally Tg is −10 ° C. to 40 ° C. ° C, more preferably -5 ° C to 35 ° C, a particle size of 50 to 500 nm, a gel fraction of 10 to 90%, and particularly 90% or more is suitable for improving disaggregation.
Moreover, the blending ratio (solid mass) of “flat pigment: synthetic resin” used in the present invention is 30:70 to 70:30, preferably 35:65 to 60:40.
When the flat pigment is less than 30%, a large amount of synthetic resin is present, so that sufficient disaggregation cannot be obtained. If the flat pigment exceeds 70%, the coating state of the paint deteriorates and sufficient moisture resistance cannot be obtained.

In order to enhance the moisture-proof effect of the moisture-proof paint in the present invention, it is preferable to use a coupling agent.
Examples of such a coupling agent include a silane coupling agent containing Si in the hydrophilic group portion, a titanate coupling agent containing Ti in the hydrophilic group portion, and an aluminum coupling agent containing Al in the hydrophilic group portion.
Examples of such a coupling agent include γ-glycidoxypropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, isopropyltri (N-aminoethylaminoethyl) titanate, and the like.

The structure of the coupling agent is roughly classified into a hydrophilic group that interacts with an inorganic compound such as a flat pigment such as a phyllosilicate compound and a hydrophobic group that interacts with an organic compound such as a resin. The portion is obtained by hydrolyzing a metal element such as Ti or Al or an alkoxy group bonded to Si.
On the other hand, as for the hydrophobic group part of the coupling agent, when the hydrophobic group part is an organic oligomer, a polymer organic film is formed on the surface of the inorganic compound, and the surface is completely hydrophobized to improve the adhesion to the resin matrix. effective. In addition, when the hydrophobic group portion has a reactive organic functional group such as an epoxy group, a vinyl group, or an amino group, the functional group and the reactive functional group of the resin matrix are cross-linked, and the adhesion to the resin matrix is further increased. Rise.

With such a coupling agent, a flat pigment is surface-treated by an integral blend method or a pretreatment method.
The integral blend method is a method in which a coupling agent is directly added to a paint containing a flat pigment and a synthetic resin latex.
The pretreatment method is a method in which a flat pigment is previously treated with a coupling agent. The addition amount of the coupling agent is 0.1 to 5 parts by mass, preferably 0.5 to 2 parts by mass with respect to 100 parts by mass of the flat pigment. When the addition amount is less than 0.1 parts by mass, the coating of the surface of the flat pigment with the coupling agent becomes insufficient, which is not preferable. When the addition amount exceeds 5 parts by mass, the effect of the coupling agent reaches its peak, which is uneconomical. It is.

  The above materials are mixed to obtain a moisture-proof coating, and if necessary at this time, a dispersant such as polycarboxylic acid, an antifoaming agent, a surfactant, and a color adjusting agent can be added.

The moisture-proof paint prepared in this way can be applied with on-machine coating equipment. That is, a coating facility is provided between a dryer part and a calendar part of a paper machine for making liner base paper, and a moisture-proof coating is applied by the coating facility.
There are no particular limitations on the coating equipment that can be used in the present invention, and known ones can be arbitrarily adopted. However, the coating method for scraping the coating surface, such as a blade coater, bar coater, air knife coater, etc., is a flat pigment. This is more preferable because it tends to promote the orientation of.
The coating amount for this moisture-proof coating of the liner, as solid per side content, 5~35g / ^{m 2,} more preferably from 7~30g / ^{m 2.}
Thus, the moisture-proof liner coated with the moisture-proof paint of the present invention by on-machine and usually dried at 110 to 150 ° C. for 30 to 120 seconds passes through the machine calendar (usually about 10 to 30 kg / cm of linear pressure). It can be operated as usual because it does not cause adhesion problems due to paint.

  As the liner base paper used in the present invention, a commonly used liner base paper can be arbitrarily used. However, in order to impart more water resistance, the paper is mixed with a water-resistant agent or dried in a paper machine. It is also possible to use a water-resistant liner base paper obtained by a method such as impregnation with a water-proofing agent.

The moisture permeability of the moisture-proof liner forming the inner and outer surfaces of the fruit and vegetable freshness-keeping cardboard box of the present invention is 10 to 300 g / m ² · 24 hr (JIS Z 020, cup method B method), and Cobb water absorption (JIS P 8140) Is 5 g / m ² · 24 hr.

Using the moisture-proof liner obtained as described above, a moisture-proof cardboard sheet as a material for the fruit and vegetable freshness-keeping cardboard box of the present invention is prepared.
In order to manufacture a corrugated cardboard sheet, it is necessary to bond a liner base paper and a core base paper, and the bonding is performed by a corrugated sheet manufacturing apparatus called a corrugator.
The corrugator is mainly composed of an SF portion for bonding the liner base paper and the core base paper, and a DF portion for further bonding the liner base paper to the core side of the single cardboard sheet bonded at the SF portion. At the time of pasting in the corrugator, the corrugated board sheet has a temperature of 150 to 200 ° C. in the press roll section of the SF section, a linear pressure of 20 to 40 kg / cm ^{2 and a} pressurization time of 0.01 to 0.20 seconds. It is bonded under the conditions of ˜200 ° C. and a linear pressure of 0.3 kg / cm ² , but the moisture-proof liner base paper of the present invention is roughened with the granular pigment exposed on the surface of the coating layer. Because the contact area of the coated surface with the roll and hot platen is small and it has heat resistance, there is no problem of fusing to the press roll or hot platen of the coated surface, and it can be manufactured exactly the same as ordinary liner base paper it can.
When manufacturing moisture-proof corrugated cardboard sheets, the above-mentioned moisture-proof liners are used for both the SF and DF-side liners, and the core base paper is bonded to the non-coated surface of the moisture-proof paint with a corrugator to form a moisture-proof cardboard sheet It is.

  Using the moisture-proof corrugated cardboard sheet thus obtained, printing, sheet punching and adhesion (box making) with a flexo folder gluer (hereinafter FFG) can be performed to produce the fruit and vegetables freshness-keeping cardboard box of the present invention. .

  By using the moisture-proof liner described above on the outside of the cardboard box, when the fruits and vegetables are packaged and stored and transported at low temperatures, the condensed water generated immediately after cooling, that is, the outside air and the cooled fruits and vegetables The amount of water absorption by the liner on the outer surface of the cardboard box is 1/20 to 1/10 of that of the general liner against the dew condensation that occurs on the outer surface of the cardboard box due to the temperature difference. The liner and core moisture of the cardboard box is maintained at the usual 7-9%. Accordingly, it is possible to prevent the cardboard box strength from being lowered and the heat insulation and cold insulation from being lowered and transported when the fruits and vegetables are packed and transported.

  In addition, by using the moisture-proof liner with the above configuration inside the cardboard box, the moisture permeability of the liner on the inner surface of the cardboard box can be prevented against transpiration water from the fruit and vegetables generated when packaging and transporting the fruit and vegetables. Is low and the permeability of water vapor is 1/5 to 1/10 of that of a general liner, preventing the penetration of water vapor into the interior of the corrugated board liner. Maintained. Accordingly, it is possible to prevent a decrease in strength of the cardboard box and a decrease in the heat insulation and cold insulation properties during the cooling and transport of fruits and vegetables.

  In the printing process of the freshness-preserving cardboard box according to the present invention, when printing using two or more colors of ink in normal flexographic printing, printing may be performed so that the printed portions of each color do not overlap each other. This is desirable from the viewpoint of preventing contamination of the printed part due to low water absorption. At this time, it is more desirable to print the printed portions of the inks of the respective colors with an interval of 2 mm or more, preferably 5 mm or more, to provide a boundary between the non-printed portions.

In the box making process of the freshness-keeping cardboard box of the present invention, when adhering the paste margin using a vinyl acetate emulsion adhesive used for bonding a normal cardboard sheet, the water absorption on both sides of the cardboard sheet is low, Insufficient adhesion may cause insufficient strength.
In order to solve such a problem, a hot melt adhesive can be used as an adhesive.
In addition, when bonding the freshness-preserving cardboard box of the present invention using a conventional vinyl acetate emulsion-based adhesive, an adhesive is applied to the paste margin portion of the cardboard at the time of box making, and the adhesive surface is aligned. It is desirable to leave under pressure for 1 hour or longer, preferably 3 to 24 hours. Specifically, after box making of cardboard boxes using FFG, etc., a cardboard box in a state where it is flattened by applying an adhesive to the adhesive margin and matching the adhesive surface, plastic string etc. every 10-20 cases , And the bundle of cardboard boxes that have been bundled horizontally and left to stand for 1 hour or more, preferably 3 hours or more in a state where a weight of 10 to 300 kg / m ² is applied, can reduce the adhesive strength of the bonded part. It can be solved. By adopting such a method, the cardboard box of the present invention can be obtained without any problem just like a normal cardboard sheet.

Hereinafter, the present invention will be described with reference to examples and comparative examples.
<Example 1>
100 parts by mass of SBR latex (HOJ4027, solid content: 48% manufactured by Nippon Zeon), 50 parts by mass of muscovite (mica A21, average particle size 22 μm, aspect ratio 20-30: manufactured by Yamaguchi Mica Industry), aminosilane coupling agent (KBM603, active ingredient 98% or more: Shin-Etsu Silicone) 0.5 parts by weight, calcium bicarbonate (BF300, average particle size 8 μm, aspect ratio 1-2: manufactured by Bihoku Powdered Industries) 5 parts by weight moisture-proof paint Was prepared.
Next, a liner base paper (ONRK220: made by Oji Paper Co., Ltd.) having a basis weight of 220 g / m ² was used as a base material, and the paint was dried and applied to a coating amount of 20 g / m ² to obtain a moisture-proof liner. .
Next, the moisture-proof liner obtained above was used as a liner on both sides of the SF side and the DF side, and a corrugator was used to bond the core base paper (S160: manufactured by Oji Paper Co., Ltd.) to produce a moisture-proof corrugated sheet of A flute.
Next, using the moisture-proof corrugated cardboard sheet, FFG (summit X: manufactured by Mitsubishi Heavy Industries) performs flexographic printing with three colors of water-based flexographic ink, punching and bonding at a speed of 200 sheets / minute, and the freshness of the fruits and vegetables of the present invention. A holding cardboard box was obtained. The form of the cardboard box was a 0201 (A-1) type cardboard box, and the box size was 403 * 285 * 136 mm. As the adhesive, a commonly used vinyl acetate emulsion adhesive was used.
Note that during printing in the FFG, the printing colors were printed so as not to overlap each other, and a non-printing portion of 5 mm or more was provided between the printing portions of each color.
After box making in the above FFG, 20 cases of flatly folded cardboard boxes were bound with a plastic string and left to stand for 5 hours under a pressure of 200 kg / m ² from above.

<Comparative Example 1>
A corrugated cardboard sheet was produced in the same manner as in Example 1 except that a general liner (ONRK220: manufactured by Oji Paper Co., Ltd.) was used as the DF side liner.
Next, using the FFG used in Example 1 so that the DF side liner (general liner) of the corrugated cardboard sheet is on the outside, as in Example 1, printing of three colors and box making are performed at 200 sheets / minute. To obtain a cardboard box. However, the three printing colors were printed so as to overlap each other.
After box making in the above FFG, the cardboard box in a flatly folded state was bound with a plastic string every 20 cases. At that time, no particular pressure was applied.

<Comparative example 2>
A corrugated board sheet was produced in the same manner as in Example 1 except that a general liner (ONRK220: Oji Paper) was used as the SF-side liner.
Next, a corrugated cardboard box was obtained in the same manner as in Comparative Example 1 with the DF side liner (moisture-proof liner) of the corrugated cardboard sheet facing outside.

<Comparative Example 3>
A moisture-proof corrugated cardboard sheet was obtained in the same manner as in Example 1. Next, a cardboard box was obtained in the same manner as in Comparative Example 1 using this moisture-proof cardboard sheet.

＜試験結果＞
＊１）外気温度２６℃条件で段ボール箱にチンゲンサイ４kgを箱詰めした後、真空予冷装置で８℃に冷却する。冷却直後のケースを手触り判定し、冷却前同様の硬さを保っているものを○、やや軟化したものを△、明らかに軟化しているものを×とする。
＊２）８℃に予冷したチンゲンサイ入り段ボール箱を保冷車に積載し、静岡から東京へ輸送する。東京到着時（約４時間経過後）、段ボール箱を手触り判定し、通常の段ボール箱同様の硬さを保っていたものを○、やや軟化したものを△、明らかに軟化しているものを×とする。
＊３）段ボール箱に1kgのテストパッケージ（JIS B 8611附属書参照）４個を箱詰めし、５℃以下に冷却した後、３０℃、９０％の環境下で箱内のテストパッケージの温度を測定する。１５℃昇温に要する時間が７時間以上のものを○、７時間未満のものを×とする。
＊４）印刷部汚染のないものを○、汚染のあるものを×とする。
＊５）接着状況を観察し、一束分２０ケースのうち、接着不完全のものが存在しなかったものを○、１ケース存在したものを△、２ケース以上存在したものを×とする。

<Test results>
* 1) Pack 4kg of Chingsaisai in a cardboard box at an outside air temperature of 26 ° C, then cool to 8 ° C with a vacuum precooler. A case immediately after cooling is judged by touching, and a case where the same hardness as that before cooling is maintained is indicated as ◯, a case where it is slightly softened as Δ, and a case where it is clearly softened as ×.
* 2) A cardboard box with Chingensai pre-cooled to 8 ° C is loaded onto a cold car and transported from Shizuoka to Tokyo. When arriving in Tokyo (after about 4 hours), the cardboard box is judged to be touched, ○ which has maintained the same hardness as a normal cardboard box, ○ which is slightly soft, △ which is clearly soft × And
* 3) Four 1kg test packages (see JIS B 8611 appendix) are packed in a cardboard box, cooled to 5 ° C or less, and then the temperature of the test package in the box is measured at 30 ° C and 90%. To do. A case where the time required for heating at 15 ° C. is 7 hours or more is indicated as “◯”, and a case where the temperature is less than 7 hours is indicated as “X”.
* 4) “O” indicates that there is no contamination of the printed part, and “X” indicates that there is contamination.
* 5) Observe the state of adhesion, and among 20 cases for a bundle, ◯ indicates that there is no incomplete adhesion, △ indicates that there is one case, and X indicates that there are two or more cases.

The present invention is a fruit and vegetables freshness-keeping cardboard box and a fruit and vegetables freshness-keeping packaging method that are suitable for packaging and transporting fruits and vegetables.

Claims (5)

The liner forming the inner and outer surfaces of the cardboard box contains a granular pigment having an aspect ratio of 3 or less and an average particle diameter of 5 to 15 μm, a flat pigment having an aspect ratio of 5 or more, and a synthetic resin emulsion on the liner base paper. A moisture-proof liner having a coating layer formed of a moisture-proof paint, the moisture permeability of the moisture-proof liner (JIS Z 0208) is 300 g / m ² · 24 h or less, and the Cobb water absorption (JIS P 8140) is 5 g / m. ^A cardboard box for maintaining the freshness of fruits and vegetables, which is 2.2 minutes or less.   2. The fruit and vegetable freshness-preserving cardboard box according to claim 1, wherein the outer surface of the cardboard box uses two or more colors of water-based flexographic ink, and the inks of the respective colors are printed without overlapping each other.   The fruit and vegetables freshness-keeping cardboard box according to any one of claims 1 to 2, wherein the paste margin part is adhered with a synthetic resin adhesive and then left to stand for 1 hour or more during box making of the cardboard box.   A freshness-keeping packaging method in which the harvested fruits and vegetables are packaged in a cardboard box and then pre-cooled. The fruit and vegetables freshness preservation packaging method. The fruit and vegetables freshness-keeping packaging method according to claim 4, wherein cooling is performed by a vacuum precooling method.