JPH01256342A - Ethylene removing agent - Google Patents

Abstract

PURPOSE:To prolong life of ethylene adsorbing ability, by covering an ethylene adsorbent with a lapping material and maintaining void part formed between the ethylene adsorbent and the lapping material at <=80% relative humidity to prepare an ethylene removing agent. CONSTITUTION:An ethylene adsorbent is covered with a lapping material and void part formed between the ethylene adsorbent and the lapping material is maintained at <=80% relative humidity to give an ethyl ene removing agent. Active carbon, zeolite or magnesium aluminate supported on potassium permanganate may be cited as the concrete example of the ethylene adsorbent. The lapping material is obtained by laminating one or more layers of a film comprising a polymer compound to a substrate such as nonwoven fabric, paper or microporous film. The ethylene removing agent is obtained by covering the ethylene adsorbent, a desiccant or humidity adjuster with the lapping material.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to an ethylene removing agent that has excellent ethylene adsorption and removal effects even in a high humidity atmosphere.

(Prior Art) Methods such as the CA storage method and the refrigeration method are known as methods for maintaining the freshness of fruits and vegetables.

Fruits and vegetables reduce their freshness due to aging-promoting hormones produced by respiration after they are harvested. The main one of these hormones is ethylene. Therefore, by removing this ethylene, the freshness of fruits and vegetables can be maintained.

Based on this knowledge, ethylene has been conventionally adsorbed using activated carbon.

However, although activated carbon exhibits excellent ethylene adsorption ability at relative humidity of about 20-50%, in a high-humidity atmosphere with relative humidity of 80-100%, it also adsorbs water vapor at the same time. Adsorbed ethylene is re-released, and as a result, sufficient ethylene adsorption capacity is not exhibited. In other words, when activated carbon is generally used as an ethylene adsorbent for freshness preservation, it is packaged in non-woven fabric with a moisture permeability of 1000 g/m2/24 hr or more as specified by JIS 20208, but the water activity of fruits and vegetables Water vapor generated by respiration easily passes through the nonwoven fabric, increasing the relative humidity of the atmosphere around the activated carbon to a high humidity of 80% or more, resulting in the activated carbon losing its ethylene adsorption ability.

In addition, if the amount of water vapor permeation is reduced by making the nonwoven fabric thicker or making the mesh denser, the amount of ethylene permeation will decrease, which is the original purpose. The removal ability will be reduced.

Figures 5 and 6 show the changes in the ethylene adsorption capacity of activated carbon due to differences in relative humidity. Figure 5 shows the case where granular bituminous coal is used at an ethylene concentration of 3%, 25°C, and ethylene injection 2.
Figure 6 shows the change in ethylene adsorption capacity after 4 hours, and Fig. 6 shows the change in ethylene adsorption capacity at 125°C with an ethylene concentration of 0.3% using coconut shell activated carbon, and 24 hours after ethylene injection. FIG.

As a solution to this drawback, copper, iron, cobalt, and nickel are attached to the surface of activated carbon (Japanese Patent Laid-Open No. 54-4788
(see Japanese Patent Laid-open No. 57-63048), and those to which a palladium compound is attached (see Japanese Patent Application Laid-open No. 57-63048) are known.

However, these conventional technologies have complicated manufacturing processes,
Due to the high production cost, it is not suitable for use on anything other than expensive fruits and vegetables.

Furthermore, even when activated carbon is loaded with an oxidizing agent for the purpose of oxidizing and removing ethylene, in a high humidity atmosphere, a film of water is formed on the surface of the activated carbon after a certain period of time, reducing its adsorption capacity.

As a method for oxidizing and removing ethylene, a method using a mixture of zeolite and potassium permanganate has been proposed (see Japanese Patent Application Laid-Open No. 53-23393). Potassium acid is a hazardous substance that contains heavy metals, and there are many safety issues, such as adhesion to fruits and vegetables with a high moisture content, and environmental pollution when disposed of after use. Another problem is that water vapor generated by the respiration of fresh fruits and vegetables condenses on the surface of the remover due to temperature changes, resulting in a significant decrease in gas adsorption ability.

(Problems to be Solved by the Invention) As described above, conventional ethylene removal agents have a problem in that their ethylene adsorption ability is significantly reduced in a high humidity atmosphere. That is, until now, no ethylene removing agent has been obtained that can reduce the adverse effects of water vapor on the ethylene removing agent and maintain its ethylene removing ability over a long period of time.

Therefore, an object of the present invention is to provide an ethylene removing agent that can maintain excellent ethylene adsorption and removal ability over a long period of time even in a high humidity atmosphere.

[Structure of the Invention] (Means and Effects for Solving the Problems) That is, the ethylene removing agent of the present invention has an ethylene adsorbent encapsulated in an encapsulant, and is formed from the ethylene adsorbent and the encapsulant. It is characterized in that the relative humidity of the void portion is maintained at 80% or less.

Furthermore, the ethylene removing agent of the present invention can also be configured to further contain a desiccant or a humidity regulator in addition to the ethylene adsorbent.

In the ethylene removing agent of the present invention, the relative humidity of the void formed by the ethylene adsorbent and the encapsulant must be 80% or less, preferably 60% or less. If this relative humidity exceeds 80%, as mentioned above, the adsorption capacity of the ethylene adsorbent decreases, which is undesirable. All voids inside the packaging material.

The ethylene adsorbent used in the present invention is not particularly limited as long as it has ethylene adsorption ability, and includes activated carbon, zeolite, magnesium aluminate supporting potassium permanganate, and aluminosilicate described in JP-A No. 58-20149. , and the brominated carbon molecular sieve described in JP-A No. 54-70457. Among these, activated carbon is preferred because it has excellent ethylene adsorption ability, is safe, and is inexpensive.

The encapsulant used in the present invention supports the ethylene adsorbent and functions to control the permeation of water vapor from the external atmosphere.

As mentioned above, the encapsulant needs to be able to adjust the amount of water vapor permeation and also be able to quickly permeate ethylene.

The amount of water vapor permeation of the enveloping material is preferably 200 g/m224 hr or less as defined by JIS 20208.

The ethylene permeation rate of the encapsulant is preferably 30 Cc/m2·hr or more at 25°C.

An example of such an enveloping material is one in which at least one film made of a polymer compound is laminated on a suitable base material.

The size, shape, etc. of the enveloping material can be appropriately determined depending on the amount of ethylene adsorbent used.

The thickness of the film made of these substrates and polymeric compounds, the number and size of ventilation holes, etc. are determined by the amount of ethylene adsorbent used to maintain the relative humidity (i.e.,
It can be determined as appropriate in relation to the size of its surface area) and the state of the atmosphere in which it is used (the relative humidity of the atmosphere in which it is used).

Examples of the base material include water-repellent nonwoven fabric, paper, and microporous film.

Examples of films made of polymeric compounds include polyethylene film (PE film), ethylene-vinyl acetate copolymer film (EVA film), unstretched polypropylene film, ionomer resin film, ethylene ethacrylate film, and polyvinyl alcohol film. be able to.

The method for producing an ethylene removing agent of the present invention includes the following steps using an encapsulant:
There are no particular restrictions on the method as long as the ethylene adsorbent can be encapsulated without direct contact with the external atmosphere.For example, the encapsulating material may be formed into a bag shape so that the polymer film side of the ethylene adsorbent is on the inside. After processing and filling the desired amount of ethylene adsorbent through the opening of the bag, the opening is sealed by a method such as a heat sealing method, an isopulse sealing method, a low frequency or high frequency sealing method, an ultrasonic sealing method, or the like. It can be manufactured by various methods.

The production of the ethylene removing agent of the present invention is preferably carried out in a dry atmosphere.

The ethylene removing agent of the present invention can also be configured such that a desiccant or a humidity regulator is wrapped in a covering material together with the ethylene adsorbent.

By configuring the ethylene removal agent of the present invention in this manner, the desiccant absorbs the water vapor that passes through the enveloping material, thereby reducing the relative humidity inside the enveloping material for a longer period of time. Since the ethylene adsorption capacity can be maintained below a fixed amount, excellent ethylene adsorption ability can be maintained even when fruits and vegetables are stored for a long period of time.

The desiccant used here is not particularly limited, and examples include silica gel, calcium chloride, silica-alumina desiccant, activated alumina, calcium sulfate, calcium oxide, and magnesium perchlorate. The humidity control agent is also not particularly limited, and examples thereof include those in which a saturated aqueous solution of magnesium chloride (salt saturated humidity control method) is supported on a porous material, and an aqueous solution support in which copper sulfate is added to glycerin.

The shape, size, etc. of the ethylene removing agent of the present invention can be determined as appropriate depending on the usage conditions.

(Example) Example 1 and Comparative Examples 1 to 3 A PE film with a 2 mm thick layer of micropores formed on the surface of a water-repellent nonwoven fabric, reinforced polyethylene net (manufactured by Nisseki Goju Products) :Product name Warif) and thickness 15ILm
The PE films provided with micropores were bonded together in this order by a heat fusion method to obtain an enveloping material. JIS of this enveloping material
The moisture permeability specified by Z 0208 is 22g/m224h
It was r.

Next, this enveloping material was formed and processed into a bag shape so that the PE ethylene film surface was on the inside. Thereafter, 200 mg of activated carbon was added as an ethylene adsorbent through the opening of the bag, and the opening was sealed by heat sealing to obtain the ethylene removing agent of the present invention.

In addition, Comparative Example 1 includes 200 mg of unencapsulated activated carbon, Comparative Example 2 includes 200 mg of a mixture of potassium permanganate and zeolite described in JP-A-53-23393, and 200 mg of zeolite is compared. This is Example 3. The removing agents of these Comparative Examples 1 to 3 were those of Example 1.
It was manufactured so that it had the same shape and the same surface edge as the remover.

The following test was conducted using this ethylene removing agent. first,
Relative humidity 50% (natural area) atmosphere and relative humidity 100
The ethylene removing agents of Example 1 and Comparative Examples 1 to 3 were placed in an Erlenmeyer flask having a capacity of 65 cc and maintained in a humidified atmosphere. Next, put 2c of ethylene into the Erlenmeyer flask.
After injecting c, the ethylene concentration in the head space after a predetermined period of time was measured by gas chromatography, and the ethylene removal ability was evaluated. The results for the natural area are shown in Figure 1, and the results for the humidified area are shown in Figure 2.

As is clear from FIG. 1, in the natural area, the removal agents of Example 1 and Comparative Example 1 showed approximately the same excellent ethylene removal effects. However, as is clear from Figure 2, in the humidified area, the remover of Example 1 still maintained an excellent ethylene removal effect, but the remover of Comparative Example 1 had a significantly reduced ethylene removal effect. was.

Examples 2 to 6 and Comparative Examples 4 to 7 Ethylene removing agents for each of the Examples and Comparative Examples were produced in the same manner as in Example 1 using the encapsulants and ethylene adsorbents shown in the table. The removers of these Examples and Comparative Examples were manufactured to have the same shape and the same surface area. In addition, in the composition of the enveloping material of Example 2, the EVA copolymerized 20% PE film means 20% by weight of EVA and PE8.
It is a 0% copolymer.

Further, the removal agents of each of these Examples and Comparative Examples were tested in a humidified area in the same manner as in Example 1. The results are shown in Figures 3 and 4.

FIG. 3 is a diagram showing the ethylene removal effects of the ethylene removal agents of Examples 2 and 3 and Comparative Examples 4 and 5. FIG. 4 is a diagram showing the ethylene removal effects of the ethylene removal agents of Examples 4 to 6 and Comparative Examples 6 and 7.

As is clear from FIG. 3, the removers of Examples 2 and 3 showed excellent ethylene removal effects. - On the other hand, the encapsulating material of the removal agent of Comparative Example 4 had almost no air permeability, so the ethylene removal effect was very low. Further, although the removal agent of Comparative Example 5 has an excellent initial ethylene removal effect, the ethylene adsorption ability rapidly decreases after about 24 hours, making it impractical.

As is clear from FIG. 4, the removers of Examples 4 to 6 had excellent ethylene removal effects. On the other hand, Comparative Example 6 gave the same results as Comparative Example 4, and Comparative Example 7 gave the same results as Comparative Example 5.

[Effects of the Invention] The ethylene removing agent of the present invention can maintain excellent ethylene adsorption/removal effects over a long period of time even in a high humidity atmosphere.

[Brief explanation of the drawing]

Figures 51 to 4 are diagrams showing the ethylene adsorption capacity of the ethylene removal agents of Examples and Comparative Examples, and Figures 5 and 6 are diagrams showing the ethylene adsorption capacity of activated carbon. 1st F, Me 1 1st sword (%RH)

Claims (4)

[Claims] (1) Ethylene removal characterized in that an ethylene adsorbent is encapsulated with an encapsulant, and the relative humidity of the void formed by the ethylene adsorbent and the encapsulant is maintained at 80% or less. agent. (2) The ethylene removing agent according to claim 1, further comprising a desiccant or a humidity regulator in addition to the ethylene adsorbent. (3) The ethylene removing agent according to claim 1, wherein the encapsulant has a moisture permeability defined by JIS Z0208 of 200 g/m^224 hr or less, and an ethylene permeation rate at 25°C of 30 cc/m^2.hr or more. . (4) The ethylene removing agent according to claim 1, wherein the ethylene adsorbent is activated carbon.