JPS60176538A - Sheet for preserving freshness of vegetables - Google Patents

Abstract

PURPOSE:To provide the titled sheet with ethylene absorption ability and water absorption ability, by blending short fibers of carbon fiber having ethylene adsorption activity with water suspension of fibrillated cellulose, processing the blend into nonwoven fabric or paper. CONSTITUTION:A cellulosic fiber having high crystallinity is carbonized in an inert gas flow to give a porous carbon fiber. Short fiber of the carbon fiber is treated with a hydrobromide and a dilute acid to give fibers having ethylene adsorption activity. The fibers are blended with an aqueous suspension of fibrillated fibers obtained by beating plant fibers, laid on a drainboard, dehydrated, and dried to give nonwoven fibric or paper.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a two-component sheet that suppresses aging of fruits and suppresses seedling formation of green fruits and vegetables, and enables a stable supply of high-quality fresh agricultural products over a long period of time. The present invention relates to a mixed nonwoven fabric or a mixed paper.

As is well known, ethylene has attracted attention as a plant hormone that exhibits a wide range of physiological activities. Therefore, attempts are being made to effectively utilize the physiological activity of ethylene. For example, ethylene absorbers are apples,
It is known to be highly effective in inhibiting ripening of tomatoes and melons, etc., in inhibiting aging in peaches, persimmons, etc., and in inhibiting the formation of seedlings in green fruit vegetables such as plums, kabosu, and asparagus. We are waiting for the transformation. Potassium permanganate preparations were first developed as ethylene absorbers;
This poses a safety problem.

Recently, products have been developed in which bromine is adsorbed onto a carbonaceous carrier having a pore size of 4 to 6 people, and products in which granular activated carbon is treated with bromate and dilute acid. Both have no problems in terms of safety, can be put to practical use, and are already commercially available. However, the ethylene processing capacity of the former is 7 cc'/g under forced circulation system, and the latter is 27 cc/g under stationary conditions, and in particular, the latter uses activated carbon, which is a black powder, so it is not practical. is greatly hindered. That is, it is not possible to prevent the contamination of the fruits and vegetables by the finely powdered activated carbon, and there are many disadvantages such as having to isolate them in a separately sealed paper bag for practical use.

In addition, fruits and vegetables are often stored tightly closed, but one of the causes of spoilage is that the moisture released by the plants themselves condenses, which interferes with their respiration. For this reason, rice grains and the like have been used since ancient times for long-term preservation of apples and the like.

As is clear from the above, for the storage of fresh agricultural products (particularly for long periods of time), it is best to use a substance that has not only the above-mentioned ethylene absorption ability but also water absorption ability.

The present invention has been made from this point of view, and is a two-component mixed nonwoven fabric or a fabric that is practical as a general packaging material, has both ethylene absorption capacity and moisture absorption capacity, and is flexible and coatable. The purpose is to provide sheets of mixed paper, etc.

The first feature of the present invention is to use porous carbon fibers obtained by carbonizing cellulose fibers with a high degree of crystallinity in an inert air stream.

Attempts have already been made to produce such fibers, and some commercial products have extremely large surface areas of 1000 to 1600 nr/g and extremely small pores of 5 to 100 nr/g in pore diameter. This means that the material has an adsorption capacity or adsorption rate several ten times higher than that of ordinary granular activated carbon.

The second feature of the present invention is that by treating such short carbon fibers with a known bromate and dilute acid,
The purpose is to create short fibers that can selectively adsorb and fix ethylene.

Granular activated carbon has already been treated with a bromate and a dilute acid to give it ethylene absorption ability, and the resulting product sealed in a thin paper bag is commercially available as a freshness-preserving agent for fruits and vegetables. Therefore, detailed studies have been made on processing methods for imparting ethylene absorption ability to carbon materials having active surfaces. That is, the bromate that is the main reaction agent in this case is preferably a potassium salt, and its concentration is preferably as high as solubility allows, and sulfuric acid is effective as a reaction aid, and its concentration is 0. It is known that around 5 mol is optimal.

The third component of the present invention is to mix the thus obtained short fibers of carbon fiber with ethylene adsorption activity and an aqueous suspension of fibrillated cellulose obtained by beating plant fibers, This is then spread thinly on a screen, dehydrated, and dried to produce nonwoven fabric or paper.

The fibrillated cellulose in this process often plays a role as a binder, and when this process is performed using a paper machine, for example, there are no carbon fibers that fall off, and it is possible to produce soft and elastic non-woven fabrics or paper. Obtainable. Further, as the vegetable fibers used in this case, general pulp liquid can be used, but bast fibers, which are used in Japanese paper, are extremely effective. In any case, by adding 10% or more to the carbon fiber, it becomes possible to play a role as a binder.

From the viewpoint of workability, the upper limit of the concentration of the water suspension during the production of nonwoven fabrics and paper is about 1%.

Of course, just like when making paper, this density is reduced, and
If the proportion of fibrillated fibers is increased, the flexibility and cushioning properties will be inferior, but a mixed nonwoven fabric or mixed paper with carbon fiber, which has a high tear strength, can be used. In addition, activated carbon fibers and fibrillated cellulose are mixed in advance to form a nonwoven fabric or paper in the manner of paper making, and this is subjected to the bromate-complementary acid treatment shown in the second component of the present invention. Even if you do, there is not much difference in the freshness preservation effect. What is important when mixing activated carbon fibers and fibrillated cellulose is that the mixing ratio has a large effect on the sealed storage of fruits and vegetables. In other words, the moisture absorption ability of cellulose prevents water vapor from condensing. In particular, when fruits and vegetables are placed in a bag made of a thin synthetic resin film and stored tightly sealed (commonly known as a vinyl pack), premature spoilage due to dew condensation becomes a problem. Therefore, when the mixing ratio of fibrillated cellulose is around 50 percent, the freshness retention capacity is doubled in case of such closed storage.

As a result of examining the ethylene processing capacity of sheets of nonwoven fabric or paper produced by the various methods described above from the pressure drop when ethylene and the absorbent are sealed, it was found that, at the same weight of carbon content, It was estimated that the absorption capacity was more than 10 times that of the absorbent treated with granular activated carbon. This indicates that the second and third treatment methods of the present invention were appropriate and were able to impart ethylene absorption ability without damaging the surface and pore structure of the activated carbon fiber, which is the starting material. It shows that. This also means that the sheet according to the present invention can quickly and reliably absorb ethylene generated from fruits and vegetables.
This suggests that it is more effective than conventional products for long-term preservation of fruits and vegetables. In addition, an excellent freshness-keeping effect can be expected due to the synergistic effect with the moisture absorption ability of the mixed cellulose. Furthermore, the sheet obtained in this manner can be brought into direct contact with target fruits and vegetables without any contamination. For this purpose, for example, the sheet may be made into a bag and wrapped directly around the whole fruit or vegetables, or it may be made into a cloth and placed under the storage box for fruit and vegetables, or the entire top may be covered, and the ethylene and moisture generated thereby. etc. can be absorbed evenly and quickly. At the same time, its flexibility and cushioning properties make it possible to minimize the occurrence of defective fruits due to mechanical factors, especially during transportation of fruits and vegetables.

Next, specific examples will be given to further demonstrate the usefulness of the present invention.

[Example 1] 50 g of potassium bromate was added to 300 cc of a 0.5 molar dilute sulfuric acid aqueous solution, heated to 50° C., and stirred well to dissolve. To this aqueous solution, 10 g of activated carbon fiber short fibers (commercial name: activated carbon fiber KF) having a thickness of 1.5 denier and a length of 3 to 5 mm, which were carbonized cellulose fibers with a high degree of crystallinity, were added. The reaction was exothermic, and the temperature of the aqueous solution began to rise immediately after it was added, reaching 60 degrees Celsius after 2 minutes. After the temperature had finished rising, it was left to stand for an additional 10 minutes. Next, the short fibers were taken out, washed with water and dehydrated three times to remove the reaction residual liquid. Next, 1.5 g of flax fiber waste having a length of about 10 mm was suspended in 50 cc of water and thoroughly beaten using a mortar to obtain a water emulsion of fibrillated cellulose. 10 g of the previously chemically treated activated carbon fibers and 1000 cc of water were added to this emulsion and thoroughly stirred, and this was used as a paper stock and deposited uniformly on a bamboo tube according to the papermaking method. After draining, it was dried at 105 degrees Celsius to obtain a black nonwoven fabric with excellent cushioning properties and a thickness of 0.5 mm and an area of 600 square centimeters. This nonwoven fabric was then cut into strips 2 cm wide, 20 cm long, and weighing about 1 g, and the strips were used as samples to examine their effectiveness in preserving the freshness of vegetables by comparing them with commercially available freshness preserving agents. .

First, on December 6th of the same year, 5 kg of chives harvested in Oita City on December 4, 1980 were divided into four equal parts of 25 kg each, one group was left to naturally grow, and the other three groups were each divided into 25 kg pieces.
It was placed in a 5 micron polyethylene film bag and sealed. One of them contained a 5g bag of Green Pack (composed of activated carbon and zeolite), which is a commercially available freshness preserving agent, and the other contained a bag containing commercially available activated carbon with bromate. - A 5 g bag (manufactured by Honshu Paper Industries Co., Ltd.) treated with a dilute acid system was placed in the bag, and 1 g of the mixed nonwoven fabric according to the present invention was placed in the remaining bag. In addition, in order to promote the generation of ethylene in the plastic bags, in addition to the above, one chive plant that had already started to rot was placed in each bag to promote rotting. All of these test samples were heated to 15 degrees C.
It was left at room temperature. As a result, on December 9th of the same year,
By the end of the day, the leaves that had been left to grow began to curl, indicating the beginning of rot. Then, on December 10th of the same year, the green pack was added, and on December 10th of the same year,
On the 13th of May, the height of leaves began to change in the activated carbon treated with bromate and dilute acid. On the other hand, in the plants according to the present invention, leaf height finally started to change on December 20th, after a further 7 days had passed.

Next, we used a similar method to examine the effect of keeping broccoli fresh.

In other words, 7.5 kg of broccoli harvested on December 3, 1982 at Tottori Prefecture Chudekai was divided into four equal parts on December 6 of the same year, and the freshness retention ability of each was measured in the same way as for chives. Judgment was made using the flowering time as a guide. However, as for the above-mentioned commercially available freshness-preserving agent enclosed in a plastic bag, one bag containing 5 g was used for each bag as in the case of chives, but 0.5 g was used for the nonwoven fabric according to the present invention. As a result, first of all, on December 8th of the same year,
In addition, those containing green puncture began to bloom on December 10th of the same year, and those containing activated carbon treated with a bromate-dilute acid system began blooming on December 12th of the same year, and their commercial value increased. lost. In contrast, the plants according to the present invention finally bloomed on December 25th of the same year.

From these examples, it is clear that the sheet according to the present invention exhibits an outstanding effect in preserving the freshness of vegetables compared to conventional products.

[Example 2] 3 g of commercially available activated carbon fiber KF paper (thickness 250 micron, area 450 square centimeters), and add it to 150 cc of a 0.5 mol complementary acid aqueous solution containing 15% by weight of potassium bromate.
immersed in water for 10 minutes. The temperature of the aqueous solution before injection is 40 degrees C.
Immediately after the KF paper was immersed, the temperature began to rise rapidly and reached 50 degrees Celsius in 4 cases after 2 minutes. Dehydration and water washing were repeated three times to remove the reaction residue, and then 105
The water was removed by drying at 30°C. Furthermore, this treatment made the starting material KF paper more flexible, and it was observed that the coating properties were improved. 15 degrees C using this treated paper
The freshness retention effect of apples, persimmons, and tomatoes at room temperature before and after was investigated. That is, on December 1, 1981, six commercially available star apples from Nagano Prefecture, Fuyu persimmons from Yamanashi Prefecture, and first tomatoes from Aichi Prefecture were each divided into three equal parts, and one group was left to stand. In addition, another group was sealed in a plastic bag together with 1 g of the nonwoven fabric produced in Example 1. In the last group, the KF paper-treated fruit prepared in this example was simply placed on the upper surface of the fruit, etc., and left open at room temperature. Two weeks later, on December 14 of the same year, the state of freshness maintenance was observed. First, tomatoes and persimmons that were left to grow lost their green color and flexibility, and their pulps softened and lost their plant bodies. In addition, part of the apple's fruit surface had turned brown, and the stalk had withered. On the other hand, in the case of the mixed nonwoven fabric according to the present invention and the one treated with Muco KF paper, although some discoloration was observed in tomatoes and persimmons, the storage condition was good and the commercial value was low. I hadn't gotten to the point where I lost it.

In addition, the apples remained in perfect condition and the handles were the same as when they were purchased.

As described above, unlike the freshness-preserving agent that is based on activated carbon and has ethylene absorption ability, the product according to the present invention can coat the entire surface of the fruit, especially when the fruit is open and closed. It was found that it has approximately the same freshness retention effect as

In addition, in a comparative experiment of maintaining the freshness of broccoli in Example 1, when 5 g of the KF paper-treated broccoli produced in Example 2 (containing 0.5 g of carbon fiber) was used instead of the mixed nonwoven fabric of Example 1, The freshness retention period was further extended by about two weeks, and it was confirmed that the freshness was maintained without blooming for a long period of about one month. This is thought to be due to the synergistic effect of the water absorbing ability of the cellulose fibers contained in the paper in large amounts.

Procedural amendment written by Manabu Shiga, Commissioner of the Japan Patent Office, 9th Prefecture, 1980 1 Indication of the case 1989 Patent Application No. 144 2, Title of the invention Sheet for preserving the freshness of fruits and vegetables 3 Relationship between the person making the amendment and the case Patent applicant address: 3814 Kamiyoshida, Fujiyoshida City, Yamanashi Prefecture Name (
Name) Feather 1) Ei Take 4, Agent 6, Number of inventions increased by amendment 1 Specification 1, Name of invention Carbon fiber and sheet for keeping fruits and vegetables fresh using the same 2, Claims ( 1) Carbon fiber obtained by subjecting porous carbon fiber short fibers obtained by carbonizing cellulose fibers with high crystallinity to a bromate-dilute acid aqueous solution treatment.

(2) Carbon fibers obtained by subjecting short fibers of porous carbon fibers obtained by carbonizing high-crystallinity cellulose fibers to bromate-dilute acid aqueous solution treatment and fibrillated cellulose fibers. A sheet for preserving the freshness of fruits and vegetables.

3. Detailed Description of the Invention The present invention provides carbon fiber and a sheet that suppresses the aging of fruits and the formation of seedlings of green fruits and vegetables, and enables a stable supply of high-quality fresh agricultural products over a long period of time. That is, it relates to a two-component mixed nonwoven fabric or mixed paper.

As is well known, ethylene has attracted attention as a plant hormone that exhibits a wide range of physiological activities. Therefore, attempts are being made to effectively utilize the physiological activity of ethylene.

For example, ethylene absorbers are highly effective in inhibiting ripening of apples, tomatoes, melons, etc., inhibiting aging of peaches, persimmons, etc., and inhibiting seedling formation of green fruit vegetables such as plums, kabosu, and asparagus. is known, and its practical application is awaited. As an ethylene absorbent, a potassium permanganate preparation was first developed, but this had problems in terms of safety.

Recently, products have been developed in which bromine is adsorbed onto a carbonaceous carrier having a pore size of 4 to 6 people, and products in which granular activated carbon is treated with bromate and dilute acid. Both have no problems in terms of safety, can be put to practical use, and are already commercially available. However, the ethylene processing capacity of the former is 7 cc/g under forced circulation method, and the latter is 2 cc/g under static conditions.
The amount of activated carbon is as low as 7 cc/g, and especially in the latter case, black powder activated carbon is used, which greatly hinders its practical use. That is, it is not possible to prevent contamination of the fruits and vegetables by the finely powdered activated carbon, and there are many disadvantages such as having to isolate them in a separately sealed paper bag for practical use. Also,
Fruits and vegetables are often stored tightly closed, but one of the causes of spoilage is that the moisture released by the plants themselves condenses, which interferes with their respiration.

For this reason, rice grains and the like have been used since ancient times for long-term preservation of apples and the like.

As is clear from the above, for the storage of fresh agricultural products (particularly for long periods of time), it is best to use a substance that has not only the above-mentioned ethylene absorption ability but also water absorption ability.

The present invention has been made from this point of view, and is a two-component mixed nonwoven fabric or a fabric that is practical as a general packaging material, has both ethylene absorption capacity and moisture absorption capacity, and is flexible and coatable. The object is to provide a sheet of mixed paper or the like and carbon fiber for producing this sheet.

The first constituent feature of the sheet according to the present invention is to use porous carbon fibers obtained by carbonizing cellulose fibers with a high degree of crystallinity in an inert air stream.

Attempts have already been made to manufacture such fibers, and some commercially available products have extremely large surface areas of 1000 to 1600 of/g, and some have extremely small pores of 5 to 100 pores in diameter. . This means that the material has an adsorption capacity or adsorption rate several ten times higher than that of ordinary granular activated carbon.

The second constituent feature of the sheet according to the present invention is that short fibers of such carbon fibers are treated with a known bromate and a dilute acid to form short fibers that can selectively adsorb and fix ethylene. That's true.

Granular activated carbon has already been treated with a bromate and a dilute acid to give it ethylene absorption ability, and the resulting product sealed in a thin paper bag is commercially available as a freshness-preserving agent for fruits and vegetables. Therefore, detailed studies have been made on processing methods for imparting ethylene absorption ability to carbon materials having active surfaces. That is, the bromate that is the main reaction agent in this case is preferably a potassium salt, and its concentration is preferably as high as solubility allows, and sulfuric acid is effective as a reaction aid, and its concentration is 0. It is known that around 5 mol is optimal.

The third component of the sheet according to the present invention is that the short fibers of carbon fibers with ethylene adsorption activity thus obtained are combined with an aqueous suspension of fibrillated cellulose obtained by beating vegetable fibers. The mixture is mixed, then spread thinly on a screen, dehydrated, and dried to produce nonwoven fabric or paper.

The fibrillated cellulose in this process often plays a role as a binder, and when this process is carried out using a paper machine, for example, all the carbon fibers that fall off are removed, and they are made of soft and highly elastic non-woven fabric or paper. In addition, as the vegetable fiber used in this case, general pulp liquid can be used, but bast fiber, which is used for Japanese paper, is extremely effective.In any case, By adding 10% or more to the carbon fiber, it becomes possible to play a role as a binder.

Water during non-woven fabric and paper manufacturing! Il! From the viewpoint of workability, it can be said that the upper limit of the concentration of the turbid liquid is around 1%.

Of course, just like when making paper, this density is reduced, and
If the proportion of fibrillated fibers is increased, the flexibility and cushioning properties will be inferior, but a mixed nonwoven fabric or mixed paper with carbon fiber, which has a high tear strength, can be used. In addition, activated carbon fibers and fibrillated cellulose are mixed in advance to form a nonwoven fabric or paper in the manner of paper making, and this is subjected to the bromate-complementary acid treatment shown in the second component of the present invention. Even if you do, there is not much difference in the freshness preservation effect. What is important when mixing activated carbon fibers and fibrillated cellulose is that the mixing ratio has a large effect on the sealed storage of fruits and vegetables. In other words, the moisture absorption ability of cellulose prevents water vapor from condensing. In particular, when fruits and vegetables are placed in bags made of thin synthetic resin membranes and stored tightly sealed (commonly known as vinyl punctures), early spoilage due to dew condensation becomes a problem. Therefore, when the mixing ratio of fibrillated cellulose is around 50 percent, the freshness retention capacity is doubled in case of such closed storage.

As a result of examining the ethylene processing capacity of a sheet of nonwoven fabric or paper produced by the sewing method described above from the pressure drop when ethylene and the absorbent are sealed, it was found that, at the same weight of carbon content, It was estimated that the absorption capacity was more than 10 times that of the absorbent treated with granular activated carbon. This means that the second and third treatment methods of the present invention are appropriate and do not damage the structure of the activated carbon fibers, such as the surface and pores, of the starting material. This also shows that the sheet according to the present invention can quickly and reliably absorb ethylene generated from fruits and vegetables.
This suggests that it is more effective than conventional products for long-term preservation of fruits and vegetables. In addition, an excellent freshness-keeping effect can be expected due to the synergistic effect with the moisture absorption ability of the mixed cellulose. Furthermore, the sheet obtained in this manner can be brought into direct contact with target fruits and vegetables without any contamination.

For this purpose, for example, the sheet may be made into a bag and wrapped directly around all the fruits and vegetables, or it may be made into a cloth and placed under the storage box for fruits and vegetables, or the sheet may be placed over the entire upper tray, thereby reducing the amount of ethylene generated. It becomes possible to absorb moisture etc. evenly and quickly. At the same time, its flexibility and cushioning properties make it possible to minimize the occurrence of defective fruits due to mechanical factors, especially during transportation of fruits and vegetables.

Next, specific examples will be given to further demonstrate the usefulness of the present invention.

[Example 1] 50 g of potassium bromate was added to 300 cc of a 0.5 molar dilute sulfuric acid aqueous solution, heated to 50° C., and stirred well to dissolve. In this aqueous solution, short fibers of activated carbon fiber (commercial name: activated carbon fiber KF) having a thickness of 165 denier and a length of 3 to 5 mm were added by carbonizing cellulose fibers with a high degree of crystallinity.

g was added. The reaction was exothermic, and the temperature of the aqueous solution began to rise immediately after it was added, reaching 60 degrees Celsius after 2 minutes. After the temperature had finished rising, it was left to stand for an additional 10 minutes. Next, the short fibers were taken out, washed with water and dehydrated three times to remove the reaction residual liquid. Next, 1.5 g of flax fiber waste having a length of about 10 mm was suspended in 50 cc of water and thoroughly beaten using a mortar to obtain a water emulsion of fibrillated cellulose. 10 g of the previously chemically treated activated carbon fibers and 1000 cc of water were added to this emulsion and thoroughly stirred, and this was used as a paper stock and deposited uniformly on a bamboo tube according to the papermaking method. After draining, dry at 105 degrees C.
A black nonwoven fabric having a thickness of 0.5 mm and an area of 600 square centimeters with excellent cushioning properties was obtained. Then, this nonwoven fabric was cut into strips of 2 cm, length 20 cm, and weight 1 g, and the strips were used as samples to examine the freshness-preserving effect of vegetables by comparing them with commercially available freshness-preserving agents. .

First, 5 kg of chives harvested on December 4, 1982 in Oita City were divided into 4 equal parts of 1.25 kg on December 6 of the same year.
The first group was left as it was, and the other three groups were each 25cm thick.
It was stored in a micron polyethylene film bag and sealed. One of them contained a 5g bag of Green Punk, a commercially available freshness preservation agent (composed of activated carbon and zeolite), and the other contained a bag containing commercially available activated carbon with bromate. - A 5 g bag (manufactured by Honshu Paper Industries Co., Ltd.) treated with a dilute acid system was placed in the bag, and 1 g of the mixed nonwoven fabric according to the present invention was placed in the remaining bag. In addition, in order to promote the generation of ethylene in the plastic bags, in addition to the above, one chive plant that had already started to rot was placed in each bag to promote rotting. These test samples were all left at room temperature of about 15 degrees Celsius. As a result, on December 9th of the same year, it was confirmed that the leaves, which had been left to grow naturally, began to curl, indicating the beginning of rot. Next, on December 10th of the same year, the leaves began to change in height, and on December 13th of the same year, the leaves began to change in height with activated carbon treated with bromate and dilute acid. Ta. On the other hand, in the case of the present invention, after 7 days have elapsed,
The leaves finally began to change their height on February 20th.

Next, we used a similar method to examine the effect of keeping broccoli fresh.

That is, 7.5 kg of broccoli harvested on December 3, 1980 in Nakaryo-cho, Tottori Prefecture was divided into four equal parts on December 6 of the same year, and the freshness retention ability of each was determined in the same way as with chives. Judgment was made using the flowering time as a guide. However, as for the above-mentioned commercially available freshness-preserving agent enclosed in a plastic bag, one bag containing 5 g was used for each bag as in the case of chives, but 0.5 g was used for the nonwoven fabric according to the present invention. As a result, first of all, on December 8th of the same year,
In addition, the one containing Green Bank began to bloom on December 10th of the same year, and the 7η containing activated carbon treated with bromate-dilute acid system began flowering on December 12th of the same year. It has lost its value. In contrast, the plants according to the present invention finally bloomed on December 25th of the same year.

From these examples, it is clear that the sheet according to the present invention exhibits an outstanding effect in preserving the freshness of vegetables compared to conventional products.

[Example 2] 3 g of commercially available activated carbon fiber KF paper (thickness 250 micron, area 450 square centimeters) was taken and immersed for 10 minutes in 150 cc of a 0.5 molar auxiliary acid aqueous solution containing 15 weight percent of potassium bromate. The temperature of the aqueous solution before injection is 40 degrees C.
Immediately after the KF paper was immersed, the temperature began to rise rapidly and reached 50 degrees Celsius after 2 minutes. Dehydration and water washing were repeated three times to remove residual reaction liquid, and then drying was performed at 105° C. to remove water. Furthermore, this treatment made the starting material KF paper more flexible, and it was observed that the coating properties were improved. Using this treated paper, the effect of preserving the freshness of apples, persimmons, and tomatoes at room temperature around 15 degrees Celsius was investigated. That is, on December 1, 1981, six commercially available Nagano Kengai star apples, Yamanashi Kengai Fuyu persimmons, and Aichi Kengai first tomatoes were each divided into three equal parts, and one group was left to naturally grow. In addition, another group was sealed in a plastic bag together with 1 g of the nonwoven fabric produced in Example I. In the last group, the KF paper-treated fruit prepared in this example was simply placed on the upper surface of the fruit, etc., and left open at room temperature. Two weeks later, on December 14 of the same year, the state of freshness maintenance was observed. First, tomatoes and persimmons that were left to grow lost their green color and flexibility, and their pulps softened and lost their plant bodies. In addition, some of the fruit surfaces of apples turn brown, and
The handle was withered.

On the other hand, in the case of the mixed nonwoven fabric according to the present invention and the one treated with KF paper, although some discoloration was observed in tomatoes and persimmons, the preservation condition was good and the product value was not lost. I wasn't quite there yet. In addition, the apples remained in perfect condition and the handles were the same as when they were purchased.

As described above, unlike the freshness preserving agent which is based on activated carbon and has ethylene absorption ability, the product according to the present invention can cover the entire surface of the fruit, especially when it is open or closed. It was found that it has approximately the same freshness retention effect as

In addition, in a comparative experiment of maintaining the freshness of broccoli in Example 1, when 1.5 g (containing carbon fiber 0.5 g) of the KF paper-treated fabric prepared in Example 2 was used instead of the mixed nonwoven fabric of Example 1. In this case, the freshness retention period was further extended by about two weeks, and it was confirmed that the freshness was maintained without blooming for a long period of about one month. This is thought to be due to the synergistic effect of the water absorbing ability of the cellulose IJll fibers contained in the paper in large amounts.

Patent Applicant Han 1) Takeei Procedures Written Amendment (Format) March 8, 1985 Manabu Shiga, Commissioner of the Patent Office 3 Relationship with the person making the amendment Patent Applicant Address Fujiyoshida City, Yamanashi Prefecture 3814 Yoshida Name: Takee Haneda (first name) 4, Agent address: 5 Tsuchiya Building, 1-14-5 Kyobashi, Chuo-ku, Tokyo
Floor (2) Supplement the power of attorney as attached.

Claims (1)

[Claims] Consists of carbon fibers obtained by subjecting short fibers of porous carbon fibers obtained by carbonizing high-crystallinity cellulose fibers to bromate-dilute acid aqueous solution treatment and fibrillated cellulose fibers. A sheet for preserving the freshness of fruits and vegetables.