JP2012110869A - Ethylene gas adsorption member, member and method for preserving food by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ethylene gas adsorption member that is easy to handle.SOLUTION: The ethylene gas adsorption member 100 includes: a first foam layer 110; a second foam layer 130; and an ethylene gas adsorption material layer 120 disposed between the first foam layer 110 and the second foam layer 130. The ethylene gas adsorption material layer 120 includes: a binder for adhesively bonding the first foam layer 110 and the second foam layer 130; and a carbon material for adsorbing ethylene gas.

Description

  The present invention relates to an ethylene gas adsorbing member, a food storage member using the same, and a food storage method.

As a technique for adsorbing and removing ethylene gas for maintaining the freshness of fruits, for example, there is one described in Patent Document 1. Patent Document 1 describes that, in addition to fibrous activated carbon and heat-fusible fibers, composite pulp is composited to obtain a porous fibrous activated carbon-containing composite sheet (hereinafter referred to as composite sheet). (Claim 1, paragraph 0011, etc.). In this composite sheet, fibrous activated carbon is bonded with synthetic pulp and fusible fibers to prevent the fibrous activated carbon from dropping from the inside of the composite sheet (paragraphs 0020 and 0056). Based on such a technique, in the improvement study of the composite sheet, from the viewpoint of using one composite sheet as a finished product, mainly by strengthening the adhesive force to keep the fibrous activated carbon inside the composite sheet. It has been studied to prevent the fibrous activated carbon from falling off.
Further, the same document describes that it is preferable to add reinforcing fibers in order to further reinforce the adhesive force.

Japanese Patent Laid-Open No. 11-1000079 JP 2001-122608 A

“Latest Adsorption Technology”, supervised by Mitsuo Tsunoda, published by General Technology Center, (1993) p. 128-129, 132-133

However, in the case of conventional composite sheets, adding synthetic pulp or reinforcing fibers to prevent dropping increases the strength of the composite sheet, but its flexibility is lost, resulting in limited use of the composite sheet. It was. For example, an ethylene gas adsorbing member used for suppressing deterioration in the quality of foods such as fruits is required to have handleability capable of various usage modes such as storage and transportation while being packed with foods. .
In such various usage modes, in the conventional composite sheet, when it comes into contact with food such as fruits or other members, fibrous activated carbon detached from the surface of the composite sheet may adhere to the food, and it is sufficiently handled. The sex could not be maintained.

According to the present invention,
A first foam layer;
A second foam layer;
An ethylene gas adsorbent layer disposed between the first foam layer and the second foam layer,
The ethylene gas adsorbing material layer is provided with an ethylene gas adsorbing member including a binder that adheres to the first foamed layer and the second foamed layer, and a carbon material that adsorbs ethylene gas.

  According to the present invention, both sides of an ethylene gas adsorbent layer containing a carbon material are configured to be sandwiched between foamed layers. For this reason, since external air and a carbon material can contact via a foaming layer, the function which an ethylene gas adsorption material layer adsorb | sucks ethylene gas can be exhibited. Moreover, since the surface of the ethylene gas adsorbent layer is protected by the foamed layer, it is possible to prevent food and other members from coming into contact with the surface of the ethylene gas adsorbent layer even in various usage modes. it can. Thereby, since it can suppress that a carbon material detach | desorbs from the surface of an ethylene gas adsorption material layer by contact with a member irrespective of a use aspect, handling of the ethylene gas adsorption member of this invention becomes easy.

  Moreover, according to this invention, the food preservation | save member containing the said ethylene gas adsorption | suction member is provided.

  Moreover, according to this invention, the food preservation | save method including the process of packaging a foodstuff with the said ethylene gas adsorption member is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the ethylene gas adsorption member which is easy to handle, a food preservation member using the same, and a food preservation method are provided.

It is sectional drawing of the ethylene gas adsorption member of this Embodiment. It is sectional drawing of the ethylene gas adsorption member of the modification of this Embodiment. It is sectional drawing of the ethylene gas adsorption member of the modification of this Embodiment. It is the upper side figure and sectional drawing of the ethylene gas adsorption member of the modification of this Embodiment. It is sectional drawing of the ethylene gas adsorption member of the modification of this Embodiment.

Embodiments of the present invention will be described below.
FIG. 1 is a cross-sectional view showing an example of the ethylene gas adsorbing member 100 of the present embodiment.
The ethylene gas adsorption member 100 of the present embodiment is disposed between the first foam layer (foam layer 110), the second foam layer (foam layer 130), and the foam layer 110 and the foam layer 130. An ethylene gas adsorbent layer 120. The ethylene gas adsorbent layer 120 contains a binder that adheres to the foam layer 110 and the foam layer 130 and a carbon material that adsorbs ethylene gas. Further, since the ethylene gas adsorbent layer 120 contains a binder, it acts as an adhesive layer that bonds the foamed layer 110 and the foamed layer 130 together.

  As shown in FIG. 1, the ethylene gas adsorbing member 100 is a laminate including a foam layer 110, an ethylene gas adsorbent layer 120, and a foam layer 130. An ethylene gas adsorbent layer 120 is provided on the entire inner surface of these foam layers 110 and 130.

  The ethylene gas adsorbent layer 120 is obtained, for example, by applying a heat treatment after applying a paint containing a binder and a carbon material that adsorbs ethylene gas.

  Although it does not specifically limit as a carbon material which adsorb | sucks ethylene gas, Various ethylene gas adsorbents containing a carbon atom other than activated carbon generally used widely can be used. In the present embodiment, the carbon material is preferably a porous body containing carbon atoms. The shape of the carbon material is not particularly limited and may be any of powder, granule, and fiber, but is preferably powder. The details of the ethylene gas adsorbent of the present embodiment will be described later.

  Although it does not specifically limit as a binder, What is heat-seal | fused with the foam layers 110 and 130 is preferable. Examples of the binder include polyurethane, polyethylene, vinyl acetate resin, silicone resin, modified silicone resin, acrylic resin, polyester resin, epoxy resin, and copolymers thereof. Among these, polyurethane, vinyl acetate resin, and ethylene vinyl acetate copolymer are preferable. Thus, the ethylene gas adsorbent layer 120 excellent in various adhesive properties can be obtained by appropriately selecting a flexible binder with high rubber elasticity. For this reason, the ethylene gas adsorption | suction member 100 excellent in flexibility and durability is obtained.

  The binder is preferably an aqueous binder soluble in an aqueous solvent containing water or alcohol. Thereby, since it becomes unnecessary to use an organic solvent as a solvent, it is possible to suppress expansion of the foam layers 110 and 130 made of sponge or the like. For this reason, it becomes possible to make the shape of the ethylene gas adsorbing member 100 as designed. Therefore, the manufacturing margin of the ethylene gas adsorbing member 100 is improved.

  Further, as the binder, a one-component binder is preferable, and a one-component aqueous binder is more preferable. By making the binder a one-component type, the labor of mixing a curing agent, a plasticizer and the like before use can be saved, so that the manufacturing process can be simplified and the manufacturing cost can be reduced. Moreover, the adhesiveness of the ethylene gas adsorption material layer 120 can be improved by using a one-pack type.

  The viscosity of the binder measured at 25 ° C. is not particularly limited, but is preferably 5 mPa · s or more and 5000 mPa · s or less, and more preferably 10 mPa · s or more and 1000 mPa · s or less. By setting the viscosity of the binder within the above range, the handling property of the paint is improved, and the ethylene gas adsorbing member 100 excellent in manufacturing stability can be obtained. In particular, when the carbon material is powder, the carbon material can be prevented from being detached and scattered during the manufacturing process. Moreover, the one where the viscosity of a binder is low is preferable from a viewpoint of increasing the compounding quantity of a carbon material.

  The mass ratio between the carbon material and the binder is not particularly limited, but is preferably 9/1 to 4/6, and more preferably 8/2 to 5/5. Thus, by appropriately selecting the mass ratio between the carbon material and the binder, the ethylene gas adsorbing member 100 having an excellent balance between the filling amount of the carbon material (in other words, the adsorption amount of ethylene gas) and flexibility is provided. Obtainable.

  The average thickness of the ethylene gas adsorbent layer 120 is not particularly limited, but is preferably 0.5 mm or more and 4 mm or less, and more preferably 1 mm or more and 3 mm or less, for example. By setting the average thickness of the ethylene gas adsorbent layer 120 within the above range, the ethylene gas adsorbent layer 120 excellent in adhesive strength and flexibility can be obtained.

  Further, the foam layers 110 and 130 are not particularly limited as long as they pass through ethylene gas, but continuous foams are preferable. The foam layers 110 and 130 are preferably soft foam sponges, and may be soft low-elastic foam sponges. Although it does not specifically limit as a material which comprises the foam layers 110 and 130, For example, a polyurethane, a vinyl chloride resin, polyethylene, a polystyrene etc. are used. By appropriately selecting the material and the manufacturing method, it is possible to improve the ethylene gas permeability, cushioning property and / or flexibility of the foam layers 110 and 130. Among these, it is preferable that the foam layers 110 and 130 are made of polyurethane continuously foamed. Thereby, the foam layers 110 and 130 excellent in the balance of ethylene gas permeability, cushioning properties and flexibility are obtained.

  Moreover, it is preferable that the foam layers 110 and 130 and the binder are made of the same kind of material. For example, the foam layers 110 and 130 are continuous foams of polyurethane, while the binder is a combination of polyurethane and the like. Thereby, adhesive properties such as adhesion between the foam layers 110 and 130 and the ethylene gas adsorbent layer 120 are improved. Accordingly, the durability of the ethylene gas adsorbing member 100 is improved, so that it can be used in various usage modes.

  Moreover, you may add various additives to the material which comprises the foam layers 110 and 130 as needed. Examples of additives include colorants, plasticizers, stabilizers, flame retardants, antioxidants, ultraviolet absorbers, antistatic agents, lubricants, antibacterial / antifungal agents, reinforcing agents, fillers, and the like. As the colorant, pigments such as inorganic pigments and organic pigments are used. By adding the pigment, it is possible to further improve the design and promote the customer's desire to purchase.

  Further, the thickness of the foam layers 110 and 130 is not particularly limited, but is preferably 1 mm or more and 10 mm or less, more preferably 2 mm or more and 7 mm or less, and further preferably 3 mm or more and 5 mm or less. By making the thickness not more than the upper limit value, the adsorption efficiency of ethylene gas can be increased. On the other hand, cushioning properties can be ensured by setting the thickness to be equal to or greater than the lower limit. Moreover, the thickness of the foam layer 110 and the foam layer 130 may be the same or different.

  Next, the effect of the ethylene gas adsorption member 100 of the present embodiment will be described.

  In the ethylene gas adsorbing member 100 of the present embodiment, since a laminated structure including the foam layer 110, the ethylene gas adsorbent layer 120, and the foam layer 130 is configured, the ethylene gas adsorbent layer 120 containing the carbon material Both surfaces are protected by being covered with foam layers 110 and 130, respectively. For this reason, also in the various usage modes of the ethylene gas adsorption member 100, it can suppress that a foodstuff and another member contact the surface of the ethylene gas adsorption material layer 120. FIG. Thereby, the frictional force and impact force generated when food or other members come into contact with each other can be reduced regardless of the mode of use, so that the carbon material is detached from the surface of the ethylene gas adsorbent layer 120. Can be suppressed. Therefore, handling of the ethylene gas adsorbing member 100 of the present embodiment is facilitated.

Furthermore, the effect of the ethylene gas adsorption member 100 of the present embodiment when used for the following applications will be described.
As a usage mode of the present embodiment, there is a usage mode used for storage, transportation, display and the like together with food such as fruits. For example, in storage and transportation, it can be used for the purpose of placing food, laying it on a packing box such as corrugated cardboard, or filling the gap between them. It can be used for the purpose of placing it on. For example, in the storage usage mode, since the surface layer of the ethylene gas adsorbent layer 120 is protected, food and other packaging members can be prevented from coming into contact with the ethylene gas adsorbent layer 120. Moreover, in the usage mode of conveyance, the impact received on the ethylene gas adsorbent layer 120 from food or other packaging members can be reduced. Thereby, since it can suppress that a carbon material adheres to the member relevant to a foodstuff or other goods, in the usage condition of a display, the ethylene gas adsorption member 100 with a foodstuff is left in front of a customer etc. in a state as it is. It is also possible to display it. Thus, since the detachment | desorption of a carbon material is suppressed in the time-dependent change of a use aspect, the ethylene gas adsorption | suction performance of the ethylene gas adsorption member 100 can be maintained. In addition, variations in ethylene gas adsorption performance among products of the ethylene gas adsorption member 100 can be suppressed. Thereby, according to this Embodiment, it becomes possible to maintain the quality of foods, such as a fruit, stably. Moreover, according to this Embodiment, since the detachment | desorption of a carbon material is suppressed, the effort which removes the carbon material adhering to foodstuffs can also be omitted. Thereby, since it is not necessary to pay attention to the carbon material adhering to merchandise and other merchandise, handling of the ethylene gas adsorbing member 100 of the present embodiment becomes much easier regardless of the mode of use.

  In addition, according to the present embodiment, desorption of the carbon material that adsorbs ethylene gas is suppressed, and therefore, depending on the mode of use, the ethylene gas adsorption performance and its change over time are suppressed from varying widely between products. .

  Moreover, according to this Embodiment, the foodstuff on the surface of the ethylene gas adsorption | suction member 100 can be directly mounted as an example of a specific usage condition. For this reason, it is easy to arrange | position a foodstuff in the position closest to this, contacting the ethylene gas adsorbent layer 120. For this reason, according to this Embodiment, the ethylene gas generated from food can be adsorbed efficiently.

  Further, according to the present embodiment, even if the ethylene gas adsorbing member 100 is deformed in a usage mode in which bending, screw bending, or the like is performed, the foam layers 110 and 130 and the carbon material are fused by the binder. Therefore, it is possible to prevent the carbon material from being detached from the ethylene gas adsorbent layer 120. Thereby, it is possible to suppress the carbon material from being desorbed from the ethylene gas adsorbing member 100 even in various usage modes.

  Furthermore, from the viewpoint of further enhancing the handling of the ethylene gas adsorption member 100, it is preferable to use soft sponges as the foam layers 110 and 130. As a result, the ethylene gas adsorbing member 100 can be freely deformed, so that the product can be appropriately protected and can be disposed in a wide variety of places. For example, it is easy to perform packaging such as covering food or filling in a gap between the packaging box and the food. Thus, by using sponge as the foam layers 110 and 130, the ethylene gas adsorbing member 100 can be used as a cushioning material to further enhance the quality maintenance performance of food. Due to such various usage modes, it is possible to improve the durability of the ethylene gas adsorbing member 100 by appropriately selecting a binder having high rubber elasticity and flexibility.

  Moreover, since the foam layers 110 and 130 are porous bodies, the ethylene gas adsorbing member 100 of the present embodiment is lightweight. By using such a lightweight member, an increase in transport weight can be suppressed during distribution, and an increase in distribution cost can be suppressed.

  In the present embodiment, it is preferable to form the ethylene gas adsorbent layer 120 on the entire surface of the foam layers 110 and 130. Thereby, compared with the case where it forms in a one part area | region, the surface area of the ethylene gas adsorption material layer 120 can be increased. In addition, the adsorption amount of ethylene gas can be improved.

  Further, the carbon material used in the present embodiment usually has a black color in many cases. Both surfaces of the ethylene gas adsorbent layer 120 containing such a black carbon material can be covered with foam layers 110 and 130 colored in white or other colors. For this reason, since the ethylene gas adsorption | suction member 100 excellent in the designability is obtained, the purchase willingness of the foodstuff used as goods can be raised.

Moreover, the ethylene gas adsorbing member 100 of the present embodiment can be used as a food storage member used in a method for storing food.
The food preservation method of the present embodiment includes a step of packaging food together with the ethylene gas adsorbing member 100 described above. As the food, for example, agricultural products containing fruits such as peaches, apples and pears are preferred. Thereby, since ethylene gas can suppress contacting with foodstuffs, deterioration of the quality of foodstuffs can be prevented.

  Next, the manufacturing method of the ethylene gas adsorption member 100 of the present embodiment will be described.

  The manufacturing method of the ethylene gas adsorption member 100 of the present embodiment includes the following steps. First, a paint containing a binder, a carbon material that adsorbs ethylene gas, and a solvent is obtained. Subsequently, this paint is disposed between the foam layer 110 and the foam layer 130. Thereafter, the foamed layer 110 and the foamed layer 130 are bonded through a layer made of a paint. Hereinafter, each process is explained in full detail.

  First, in the step of obtaining a paint, for example, after adding a binder and a carbon material in a solvent, they are mixed at an appropriate time and temperature. Here, as the solvent, water or an alcohol, an aqueous solvent such as a mixed solvent of water and alcohol, or an organic solvent can be used. Among these, an aqueous solvent is preferable.

  Subsequently, a layer made of a paint is formed on the foam layer 110. For example, a paint may be applied to the entire main surface of the foam layer 110, or a film-like adhesive layer obtained by drying the paint may be attached to the main surface of the foam layer 110. Thereafter, the foamed layer 110 and the foamed layer 130 are bonded to each other so as to sandwich a layer made of a paint, thereby obtaining a laminate.

  Here, the application method is not particularly limited, but a conventionally known method can be used. For example, a roll coater, an air knife coater, a bar coater, a spray coater, an ink jet coater, a die coater, or the like can be used as a coating apparatus.

Next, the obtained laminate is heat-treated to fuse the binder with the foam layer 110 and the foam layer 130.
Through the above steps, the ethylene gas adsorbing member 100 of the present embodiment is obtained.

As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.
Next, various modifications of the present embodiment will be described.

FIG. 2 is a cross-sectional view of the ethylene gas adsorbing member 200 of the first modification.
As shown in FIG. 2, as a first modification, an ethylene gas adsorbing member 200 includes a foam layer 210 (first foam layer), an ethylene gas adsorbent layer 220 (third foam layer), and a foam layer. It is composed of a laminate of three foam layers 230 (second foam layer). The ethylene gas adsorbent layer 220 is composed of a third foam layer impregnated with at least the above-mentioned binder and carbon material. As the third foam layer, the same kind as the above-mentioned foam layer is used.

  In the first modification, the ethylene gas adsorbing material layer 220 is impregnated with the third foamed layer with a binder and a carbon material. For this reason, the film thickness controllability of the ethylene gas adsorbent layer 220 can be further improved by squeezing between the rollers. In other words, the thickness of the ethylene gas adsorbent layer 220 can be made as designed. Thereby, the ethylene gas adsorption member 200 excellent in productivity is obtained. Moreover, the effect of embodiment is also acquired.

Next, the manufacturing method of the ethylene gas adsorption member 200 of the first modification will be described.
First, a binder, a carbon material, and a solvent are mixed to obtain a paint. The third foam layer is immersed in this paint. Subsequently, the foamed layer 210 and the foamed layer 230 are arranged via the third foamed layer to obtain a laminate. An ethylene gas adsorbing member 200 is obtained by heat-treating the laminate at an appropriate temperature.

  Further, in the ethylene gas adsorbent layer 220 of the first modified example, a non-woven fabric can be used instead of the third foam layer. As a use mode of this nonwoven fabric, a carbon material may be encapsulated in a bag-shaped nonwoven fabric in which a carbon material is kneaded with a binder or impregnated with the binder. As a result, the same effect as that of the first modified example can be obtained, and an ethylene gas adsorbing member with further excellent flexibility can be obtained. Although it does not specifically limit as a nonwoven fabric used for such a thing, For example, a flexible nonwoven fabric is preferable.

FIG. 3 is a cross-sectional view of the ethylene gas adsorbing member 102 of the second modification.
As shown in FIG. 3, in the second modified example, in addition to the laminate composed of the foam layer 110, the ethylene gas adsorbent layer 120, and the foam layer 130, the ethylene gas adsorbent layer 122 is formed on the foam layer 110. The foam layer 112 may be laminated via Moreover, you may repeat these lamination | stacking more than once. Thereby, the adsorption amount of ethylene gas can be improved with cushioning properties. Moreover, the effect of this Embodiment is also acquired.

FIG. 4A is a top view of the ethylene gas adsorbing member 104 of the third modification. FIG. 4B is a cross-sectional view of the ethylene gas adsorbing member 104 as seen from the arrow AA ′.
As shown in FIG. 4A, in the ethylene gas adsorbing member 104 of the third modified example, the foam layer 114 is embedded in the concave portion of the foam layer 134 via the ethylene gas adsorbent layer 124. Yes. Thus, the shape and volume of the ethylene gas adsorbent layer 124 formed between the foam layer 114 and the foam layer 134 can be freely changed. That is, the ethylene gas adsorbent layer 124 may be formed so as to surround part or all of the periphery of the foam layer 114 in the top view, and / or part of the periphery of the foam layer 114 in the cross-sectional view. The ethylene gas adsorbent layer 124 may be formed so as to surround the whole. For this reason, the ethylene gas adsorption | suction member 104 adapted to various usage modes can be provided. Further, a plurality of ethylene gas adsorbing members 104 may be used in such a manner that the foam layer 114 is inside. Moreover, the effect of this Embodiment is also acquired.

  FIG. 5A is a cross-sectional view of the ethylene gas adsorbing member 106 of the fourth modified example. FIG. 5B is a cross-sectional view of the ethylene gas adsorbing member 108 of the fifth modification. In these modified examples, a recess 140 or a recess 142 for placing a product such as food is provided on the foam layer 116 or the foam layer 118. For this reason, it is possible to easily arrange the products and to prevent the positional deviation. Further, since the distance between the merchandise and the ethylene gas adsorbent layer 120 or the ethylene gas adsorbent layer 124 becomes shorter in the merchandise arrangement portion, the ethylene gas can be more efficiently adsorbed. Moreover, foods such as fruits may be disposed in the gap formed by the recesses 140 and 142 by using these layers. In addition, on one surface, a plurality of recesses 140 and 142 may be provided. Moreover, the effect of this Embodiment is also acquired.

  Further, the ethylene gas adsorbent of the present embodiment, which is an example of a carbon material, will be described in detail below.

  The ethylene gas adsorbent of the present embodiment adsorbs ethylene gas. Ethylene acts as a hormone that promotes the respiration of plants, and causes the decay of foods such as crops and shortens the storage period. For example, the ethylene gas adsorbent of the present embodiment can efficiently adsorb ethylene gas generated from or present in food. For this reason, if the ethylene gas adsorbent of Embodiment 1 is used, it is possible to suppress the deterioration of the quality of the food and to preserve the food for a long time.

  The ethylene gas adsorbent of the present embodiment is specified by the ratio of two kinds of specific surface areas, S1 and S2. That is, when the specific surface area obtained by the nitrogen adsorption method is S1 and the specific surface area obtained by the carbon dioxide adsorption method is S2, S2 / S1 is 1 or more.

  The specific surface area S1 obtained by the nitrogen adsorption method (hereinafter, referred to as nitrogen specific surface area S1) is a parameter reflecting the total number of pores having a wide pore size distribution.

  In the conventional activated carbon, this nitrogen conversion specific surface area S1 is controlled as an index of the specific surface area (Non-patent Document 1 and Patent Document 1). The document describes that an activation treatment is performed using an activator or an activation gas in order to increase the specific surface area S1 in terms of nitrogen. By performing carbonization treatment on the carbon material together with this activation treatment, the pore diameter of the voids generated during carbonization can be further expanded. Therefore, in the conventional activated carbon, the activated carbon has a large surface area by controlling the nitrogen equivalent specific surface area S1 by such activation treatment.

  However, according to the study by the present inventors, even if the specific surface area S1 in nitrogen conversion is increased by the conventional activation treatment, the adsorption characteristics such as the adsorption amount and adsorption stability of ethylene gas are improved only to a certain extent in the activated carbon. It turned out not to.

As a result of further examination by the present inventors, the tendency of increase / decrease in specific surface area S2 (hereinafter referred to as carbon dioxide equivalent specific surface area S2) obtained by the carbon dioxide adsorption method is in good agreement with the tendency of increase / decrease in the adsorption amount of ethylene gas. I found out. The kinetic molecular diameter of carbon dioxide gas used for measuring the carbon dioxide equivalent specific surface area S2 is smaller than that of nitrogen gas. For this reason, it is thought that the pore of the size which cannot be detected with nitrogen gas can be detected with carbon dioxide gas.
Based on the above experimental facts, the present inventors made the following hypothesis.
(1) There are pores of a size suitable for adsorbing ethylene molecules.
(2) The ethylene gas adsorption performance can be effectively improved by increasing the pores of the size (1).
Based on this hypothesis, the present inventors have found an index indicating how many pores of a size suitable for adsorbing ethylene molecules exist, and studied to control the index to an appropriate value.

From various experimental results, it was concluded that the ratio of the specific surface area S1 in terms of nitrogen and the specific surface area S2 in terms of carbon dioxide, S2 / S1, is appropriate as the index of (2). That is, the present inventors have found a relationship that increasing S2 / S1 increases pores having a size suitable for adsorbing ethylene molecules.
Here, “size suitable for adsorbing ethylene molecules” means a size that realizes a more thermodynamically stable state. That is, ethylene gas tends to be easily adsorbed in pores having a size suitable for adsorbing ethylene molecules.

  As described above, in the ethylene gas adsorbent of the present embodiment, the carbon dioxide equivalent specific surface area S2 / nitrogen equivalent specific surface area S1 (hereinafter referred to as S2 / S1) is adopted, and the raw materials and the production method are appropriately selected. Therefore, the value of this ratio is set to 1 or more. Thereby, the ethylene gas adsorption agent excellent in the adsorption characteristic of ethylene gas can be obtained.

On the other hand, S2 / S1 of the activated carbon described in Patent Document 2 and Non-Patent Document 1 is at most 0.5, which is significantly lower than that of the present embodiment.
As described above, in the conventional activated carbon, in order to increase the amount of gas adsorption, it is most important to increase the specific surface area by using activation treatment. This activation treatment expands the pore diameter of voids generated during carbonization. Thereby, the pore diameter of the pores that easily adsorb ethylene gas is also expanded. As a result, while the nitrogen equivalent specific surface area S1 increases, the carbon dioxide equivalent specific surface area S2 decreases. Therefore, S2 / S1 of the conventional activated carbon is significantly lower than that of the present embodiment.

  Hereinafter, the ethylene gas adsorbent of the present embodiment will be described in detail.

  In the ethylene gas adsorbent of the present embodiment, the lower limit value of S2 / S1 is not particularly limited, but is preferably 1 or more, more preferably 1.5 or more. By setting S2 / S1 within the above range, an ethylene gas adsorbent having excellent ethylene gas adsorption characteristics can be obtained. The upper limit value of S2 / S1 is not particularly limited, but is preferably 1000 or less, for example, and more preferably 100 or less. Moreover, in the ethylene gas adsorbent of the present embodiment, by setting the lower limit value of S2 / S1 to 1.5 or more, high gas adsorption performance and performance for maintaining the gas adsorption performance for a certain period can be realized. Furthermore, it is also possible to suppress a large variation between products in the ethylene gas adsorption performance and its change with time.

  Further, as the ethylene gas adsorbent of the present embodiment, a porous body obtained by carbonizing an organic substance containing carbon atoms by heat treatment can be used. Although it does not specifically limit as this organic substance, Fiber-type raw materials, such as petroleum pitch, coal pitch, polyacryl tolyl type | system | group, rayon type | system | group, and phenol resin type; Examples thereof include yeasts such as yeast and yeast lees. Moreover, as an organic substance, the compound containing saccharides is preferable. Examples of the saccharide include monosaccharides, oligosaccharides in which about 2 to 20 molecules of monosaccharide are bound, and polysaccharides such as starch and cellulose. Among these, cellulose is preferable.

The nitrogen equivalent specific surface area S1 is preferably calculated based on a nitrogen adsorption isotherm. For example, nitrogen gas is introduced in a state where the ethylene gas adsorbent is cooled to −196 ° C., and the adsorption amount V [cm ³ / g] of nitrogen gas is measured by a volumetric method. The pressure P [mmHg] of the nitrogen gas introduced at this time is gradually increased. The relative pressure P / P ₀ is obtained by dividing the pressure P [mmHg] by the saturated vapor pressure P ₀ [mmHg] of nitrogen gas. A nitrogen adsorption isotherm is obtained by plotting the adsorption amount V [cm ³ / g] against the relative pressure P / P ₀ . As a pore distribution analysis based on this nitrogen adsorption isotherm, for example, α _s analysis is generally known. The α _s analysis is a method for analyzing the pore structure in comparison with the standard isotherm of a nonporous solid. Kaneko and C.K. This can be done according to the procedure described in Ishi, Colloid Surface, 1992. In this case, α _s analysis was applied to a nitrogen adsorption isotherm obtained by an automatic gas adsorption apparatus (Belsorb 28SA, manufactured by Nippon Bell Co., Ltd.). Non-porous carbon black data is used for the standard nitrogen adsorption isotherm, and the adsorption amount of P / P ₀ = 0.4 in this standard isotherm is used as an index, and this is used for each relative pressure of the adsorption isotherm of the sample. By comparing with the amount of adsorption, the pore surface area of the micropore region having a pore diameter of 2 nm or less was evaluated.

Further, the nitrogen-converted specific surface area S1 obtained by a nitrogen adsorption isotherm measured at -196 ° C is not particularly limited as long as S2 / S1 satisfies a desired value, but the lower limit is preferably 1 m ² / g or more. Yes, more preferably 10 m ² / g or more, while the upper limit value is preferably 1000 m ² / g or less, more preferably 600 m ² / g or less (the values of these nitrogen conversion specific surface areas S1 are is calculated using the alpha _s analysis. However, in the case a nitrogen adsorption isotherm not according to alpha _s analysis, when N ₂ adsorption amount is very small, such as there is no space to enter the N ₂ gas It is determined that the material is non-porous, and the specific surface area S1 in terms of nitrogen is 1 m ² / g). By making the nitrogen conversion specific surface area S1 within the above range, the adsorption efficiency of ethylene gas can be improved. For example, the nitrogen equivalent specific surface area S1 can be within the above range by appropriately selecting the raw materials and the production method.

The carbon dioxide equivalent specific surface area S2 is preferably calculated based on a carbon dioxide adsorption isotherm. For example, adsorption measurement of carbon dioxide at room temperature (automatic gas adsorption device (Belcorp 28SA, manufactured by Nippon Bell Co., Ltd.)) is performed to obtain a carbon dioxide adsorption isotherm. As a pore distribution analysis based on the carbon dioxide adsorption isotherm, for example, DR analysis is generally known. The DR analysis was performed using F. Martin, et al. , Separation and Purification Technology, 2010. The DR analysis is one of pore structure analysis methods mainly applied to an isotherm showing type I. When the adsorption potential distribution micropores is assumed to follow a Gaussian distribution, between the adsorption amount V and the relative pressure P / P _0, the following relationship holds.
V = V ₀ exp [− (A _p / βE ₀ ) ² ]
Where A _p = RTln (P ₀ / P)
A _p : adsorption potential, V ₀ : micropore capacity, β: affinity coefficient, E ₀ : characteristic adsorption energy V ₀ from an intercept of a plot of lnV and (P ₀ / P) ² logarithmically taking both sides of the above equation. E ₀ can be calculated from the slope. In this document, β = 0.36 is used as room temperature data for carbon dioxide, and a specific gravity of 1.035 is used to convert the amount of adsorption.

Further, the carbon dioxide equivalent specific surface area S2 obtained by carbon dioxide adsorption isotherm measured at 25 ° C. is not particularly limited as long as S2 / S1 satisfies a desired value, but the lower limit is preferably 250 m ² / g or more. More preferably, it is 500 m ² / g or more, while the upper limit is preferably 2000 m ² / g or less, more preferably 1500 m ² / g or less (these specific surface area S2 in terms of carbon dioxide is Calculated based on DR analysis). By setting the carbon dioxide equivalent specific surface area S2 within the above range, the adsorption amount of ethylene gas can be improved. Moreover, for example, the carbon dioxide equivalent specific surface area S2 can be set within the above range by appropriately selecting the raw materials and the production method.

  Further, in the ethylene gas adsorbent of the present embodiment, the amount of carbon dioxide adsorbed at an equilibrium pressure of 20 kPa obtained by a carbon dioxide adsorption isotherm measured at 25 ° C. is not particularly limited, but is 0.5 mmol / g or more. Is preferable, and 1.0 mmol / g or more is more preferable. The carbon dioxide equivalent specific surface area S2, which is an index of the adsorption amount of ethylene gas, is calculated from the pressure and the adsorption amount of carbon dioxide. For this reason, increasing the adsorption amount of carbon dioxide at the equilibrium pressure of 20 kPa indicates that a predetermined amount of ethylene gas can be adsorbed even when the equilibrium pressure is low.

  Further, in the ethylene gas adsorbent of the present embodiment, the adsorption amount of ethylene gas measured at 25 ° C. and an equilibrium pressure of 20 kPa is not particularly limited, but is preferably 0.6 mmol / g or more, and 0.8 mmol / g or more. Is more preferable, and 1.5 mmol / g or more is more preferable. Increasing the amount of ethylene gas adsorbed at the equilibrium pressure of 20 kPa indicates that a predetermined amount of ethylene gas having a low partial pressure can be adsorbed.

At the initial stage when ethylene gas is generated from food, the ethylene gas amount is as small as several ppm, so the partial pressure of ethylene gas is low. An index indicating the adsorption characteristic of low partial pressure ethylene gas at the initial stage when ethylene gas is produced from such food is the adsorption characteristic of ethylene gas under the low equilibrium pressure. In the ethylene gas adsorbent of the present embodiment, the range of low equilibrium pressure as an index is set to 10 kPa to 50 kPa from the viewpoint that the partial pressure of ethylene gas in the initial stage is low. Also, in this low equilibrium pressure range, an equilibrium pressure of 20 kPa is adopted as an optimal index from the viewpoint of increasing the rate of increase in the adsorption amount of ethylene gas.
In the ethylene gas adsorbent of the present embodiment, even when the ethylene gas has a low partial pressure in the initial stage, (i) by increasing the adsorption amount of ethylene gas under a low equilibrium pressure and / or (ii) low equilibrium. By increasing the adsorption amount of carbon dioxide under pressure, it is possible to secure a predetermined value for the adsorption amount of ethylene gas. Thereby, since ethylene gas can be adsorbed to some extent from the production start stage of ethylene gas, food deterioration can be further suppressed. The measurement temperature of 25 ° C. is assumed to be stored at room temperature. For example, when refrigerated storage is performed in transportation or the like, the adsorption amount of carbon dioxide and / or ethylene gas under a low equilibrium pressure in the ethylene gas adsorbent of the present embodiment can be determined by matching the temperature of the refrigerated storage with the measurement temperature. . Moreover, the adsorption amount of ethylene gas or carbon dioxide at the time of low equilibrium pressure can be set within the above range, for example, by appropriately selecting a raw material and a production method.

  In the ethylene gas adsorbent of the present embodiment, the adsorption amount of ethylene gas measured at 25 ° C. and an equilibrium pressure of 100 kPa is not particularly limited, but is preferably 1.0 mmol / g or more, and 2.0 mmol / g or more. Is more preferable. Increasing the amount of ethylene gas adsorbed at the equilibrium pressure of 100 kPa indicates that ethylene gas can be adsorbed sufficiently.

  The atomic ratio of oxygen atom (hereinafter referred to as O) / carbon atom (hereinafter referred to as C) of the ethylene gas adsorbent of the present embodiment is not particularly limited, but is preferably 0.01 or more and 0. .3 or less, more preferably 0.1 or more and 0.2 or less. The atomic ratio of hydrogen atom (hereinafter referred to as H) / C in the ethylene gas adsorbent is not particularly limited, but is preferably 0.01 or more and 0.6 or less, more preferably 0.1 or more. 0.2 or less. By setting the atomic ratio of O / C and / or the atomic ratio of H / C within the above range, an ethylene gas adsorbent excellent in ethylene gas adsorption efficiency can be obtained. In addition, as a method for measuring the masses of O, H, and C in the ethylene gas adsorbent, an elemental analyzer using a general combustion method (Yanako Analytical Industries, Ltd. CHN CORDER) can be used.

  Next, the manufacturing method of the ethylene gas adsorbent of the present embodiment will be described.

The manufacturing method of the ethylene gas adsorbent of the present embodiment includes a step of carbonizing an organic substance containing carbon atoms by performing a heat treatment without performing an activation treatment. In this document, the activation treatment means a general-purpose method such as a chemical activation method using an activator such as an alkali metal or an alkaline aqueous solution, and a gas activation method using water vapor or carbon dioxide. In the heat treatment according to the present embodiment, the carbonization yield (remaining carbon ratio) is preferably 50% or less, more preferably 80% or less, based on the point at which the peak is reached once. It means performing heat treatment. Such an environment can be achieved, for example, by using a sealed device or a sealed space using an inert gas, or by appropriately adjusting the heat treatment temperature.
Details will be described below.

When using the said sealing apparatus, organic substance is heat-processed with an electric furnace, for example. It is desirable that the electric furnace be in an environment that does not reduce the carbonization yield (residual carbon ratio). When the inert gas is used, for example, the organic substance is heat-treated in an inert gas atmosphere. The inert gas is not particularly limited, and examples thereof include noble gases such as N ₂ gas and Ar gas. In this embodiment, _{N 2} gas is preferable to achieve high carbonization yield, and more preferably at least 99.9995% pure _{N 2} gas. Although it does not specifically limit as temperature conditions of heat processing, For example, Preferably it is 400 to 1000 degreeC, More preferably, it is 500 to 900 degreeC, More preferably, it is 700 to 900 degreeC. Among these, a temperature condition around 700 ° C. is particularly preferable. By appropriately selecting the temperature conditions for the heat treatment, the adsorption characteristics of ethylene gas can be improved.

  Next, a specific example using a sealing device is shown. For example, first, an organic substance (for example, cellulose) is put in a sealing device (for example, a crucible). Next, heat treatment is performed in a sealed state under conditions where the tar content does not volatilize. Thus, it is preferable to fix the tar content as a carbon content without discharging it as it is. Thereby, the adsorption characteristic of ethylene gas of the ethylene gas adsorbent can be further improved.

  As described above, a general method for producing activated carbon is to additionally increase the surface area of a carbon material by activation treatment. For this reason, activated carbon having a developed pore structure is obtained, and a large weight reduction (carbon depletion) occurs before the activated carbon is obtained from the carbon material.

  On the other hand, in this Embodiment, the said activation process is not performed. For this reason, it is presumed that the formation of pores with a wide pore distribution that general activated carbon has is suppressed, and pores having a pore diameter that easily adsorbs ethylene gas can be efficiently maintained. Further, carbonization can be performed in a temperature range where thermal weight loss hardly occurs, and since activation treatment is not required, low cost can be reduced.

  As described above, the ethylene gas adsorbent according to the present embodiment can be obtained by a simple technique of thermally decomposing an organic substance, particularly preferably cellulose.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail with reference to an Example, this invention is not limited to description of these Examples at all.

[Example 1]
Cellulose heat treated at 700 ° C. (2931-1M, manufactured by Kanto Chemical Co., Ltd.) is made into an ethylene / vinyl acetate copolymer (Showa Denko, P-4N), and the solid content ratio is resin: cellulose = 2: 8. Thus, a coating material having a solid content of 45 w% was produced.
A paint was applied to one side of a polyurethane foam 100 mm × 100 mm thickness 7 mm, which was a continuous foam, and the application surface of the two sponges was bonded together to produce a sandwich made of sponge. This sandwich was heat-treated at 120 ° C. for 1 hour to obtain an ethylene gas adsorbing member.
As a result, the two polyurethane sponges were bonded, and a layer containing 3 g of heat-treated cellulose was formed between the sponges.
This ethylene gas adsorbing member had an outer surface of a single polyurethane sponge surface, and the cellulose heat treatment body was not dropped and scattered. The ethylene gas adsorbing member was cut into a width of 8 mm and a length of 30 mm to produce a sump. As a result of measuring the adsorption amount of ethylene gas of this sample, the adsorption of 1.20 mmol / g was confirmed.
Measurement conditions for ethylene gas adsorption:
Apparatus: High-precision fully automatic gas adsorption device BELSORP 28SA (made by Nippon Bell Co., Ltd.)
Conditions: 20 hours at room temperature, vacuum degassed to 10 ⁻⁵ Pa, then measured isotherm at 25 ° C. to equilibrium pressure of 100 kPa

[Example 2]
Cellulose heat-treated at 700 ° C. (manufactured by Kanto Chemical Co., Inc., 2931-1M) is added to a water-soluble polyurethane solution (Elastron E-37, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) with a solid content ratio of resin: cellulose = 4: 6. In this way, a coating material having a solid content of 30 w% was produced.
A polyurethane sponge having a thickness of 5 mm was immersed in the paint. Thereafter, the impregnated polyurethane sponge was squeezed with a gap of 3 mm between the two rollers, sandwiched between two untreated polyurethane sponges of 5 mm, and heat-treated at 80 ° C. for 30 mins, 100 ° C. for 1 hr, and 120 ° C. for 30 mins.
Three polyurethane sponges were bonded to form a single laminated sponge of 100 mm × 100 mm to which 12 g of heat-treated cellulose adhered. This laminated sponge was cut into a width of 8 mm and a length of 30 mm to obtain a sample. About this sample, the adsorption amount of ethylene gas was measured on the same conditions as Example 1, As a result, 1.05 mmol / g adsorption | suction was confirmed.

[Example 3]
After impregnating 7 wt% diluted solution of water-soluble polyurethane solution (Elastron E-37, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) on one side of a 5 mm polyurethane sponge to a depth of about 1 mm (distance from the surface in the thickness direction) And drying at 60 ° C. for 30 minutes. Two pieces of this sponge are cut into a width of 8 mm and a length of 30 mm.
On the other hand, the nonwoven fabric (Benlyse (registered trademark) SN140, manufactured by Asahi Kasei Fibers Co., Ltd.) is soaked and impregnated in a solution obtained by diluting a thermoplastic polyurethane solution (8012u, manufactured by Sannan Gosei Co., Ltd.) to 7 w%, and then impregnated at 60 ° C. Drying for 30 minutes was performed. The nonwoven fabric was formed into a bag shape having a width of 6 mm and a length of 25 mm, and 0.3 g of cellulose (2931-1M, manufactured by Kanto Chemical Co., Ltd.) heat-treated at 700 ° C. was enclosed therein. The non-woven bag encapsulating the cellulose was sanded so that the surface impregnated with the above-mentioned sponge: water-soluble polyurethane solution having a width of 8 mm and a length of 30 mm touched the non-woven bag, and a load of 60 g / cm ² was applied (the sponge was Heated at 120 ° C. for 30 minutes. The finished sample became a single sponge that was very supple and did not leak due to fine powder.
The ethylene adsorption amount of this sample was measured under the same conditions as in Example 1. As a result, it was 1.63 mmol / g.

[Example 4]
A commercially available peach was allowed to stand on the sample obtained in Example 1 spread on the bottom of the box. The peach was stored with the sample in the refrigerator for 30 days. Both the firmness and color of the peach after storage were good. In addition, when stored at 25 ° C. for 7 days, the peaches were good in firmness and color, and very good in taste and aroma.
In addition, when the sample obtained in Example 2 or 3 was used, as in the sample obtained in Example 1, the peach had good firmness and color, and good taste and aroma. .
[Comparative Example 1]
On the other hand, it carried out on the conditions similar to Example 4 except having stood the commercial product peach on the sponge spread | laid in the bottom of the box. The shape of the peach after storage in Comparative Example 1 was deformed by its own weight, and its color was brown.

100 ethylene gas adsorbing member 102 ethylene gas adsorbing member 104 ethylene gas adsorbing member 106 ethylene gas adsorbing member 108 ethylene gas adsorbing member 110 foam layer 112 foam layer 114 foam layer 116 foam layer 118 foam layer 120 ethylene gas adsorbent layer 122 ethylene gas adsorption Material layer 124 Ethylene gas adsorbent layer 130 Foam layer 134 Foam layer 140 Recess 142 Recess 200 Ethylene gas adsorbent member 210 Foam layer 220 Ethylene gas adsorbent layer 230 Foam layer

Claims (11)

A first foam layer;
A second foam layer;
An ethylene gas adsorbent layer disposed between the first foam layer and the second foam layer,
The ethylene gas adsorbing material layer is an ethylene gas adsorbing member including a binder that adheres to the first foaming layer and the second foaming layer, and a carbon material that adsorbs ethylene gas.   The ethylene gas adsorbing member according to claim 1, wherein the binder includes at least one selected from the group consisting of polyurethane, polyethylene, vinyl acetate resin, acrylic resin, polyester resin, and epoxy resin.   The ethylene gas adsorbing member according to claim 2, wherein the binder is an aqueous binder.   4. The method according to claim 1, wherein the first foam layer and the second foam layer are made of at least one selected from the group consisting of polyurethane, vinyl chloride resin, polyethylene, and polystyrene. 5. The ethylene gas adsorbing member described.   The ethylene gas adsorbing member according to any one of claims 1 to 4, wherein the first foam layer and the second foam layer are sponges.   The ethylene gas adsorbing member according to any one of claims 1 to 5, wherein the ethylene gas adsorbing material layer is constituted by a third foamed layer impregnated with at least the binder and the carbon material. The carbon material is
The specific surface area determined by the nitrogen adsorption method is S1,
When the specific surface area determined by the carbon dioxide adsorption method is S2,
The ethylene gas adsorption member according to any one of claims 1 to 6, wherein S2 / S1 is 1 or more.   The ethylene gas adsorbing member according to any one of claims 1 to 7, wherein the first foam layer and the second foam layer are 10 mm or less.   The ethylene gas adsorption member according to any one of claims 1 to 7, which is used as a cushioning material for protecting food.   The food preservation | save member containing the ethylene gas adsorption member of any one of Claim 1 to 9.   The food preservation method including the process of packaging a foodstuff with the ethylene gas adsorption member of any one of Claim 1 to 9.

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