JP2585076B2 - Freshness retention sheet - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a freshness maintaining sheet, and more particularly, to a freshness maintaining sheet capable of adjusting moisture by itself.

(Prior Art) Conventionally, various kinds of freshness holding sheets have been proposed as a sheet for wrapping vegetables, fruits and the like when carrying them so as to maintain the freshness.

For example, as shown in FIG. 4, a water-absorbing agent (3) composed of a powdery superabsorbent molecule between two sheets of paper (2) and a gas-absorbing agent (4) also in the form of a powder. And a sheet (1) obtained by covering the paper (2) with a bag (5) made of a nonwoven fabric. According to the sheet (1), since the sheet (1) is provided with the above-described configuration, so-called drainage due to excessive moisture and so-called drainage due to dew condensation water are prevented, and further, since water is retained in the sheet (1), vegetables and fruits can be obtained. Etc. are prevented from drying. However, when this sheet (1) is used as a freshness retaining sheet, it prevents moisture evaporated from vegetables, fruits, etc. from leaching from the sheet (1) when wrapping vegetables, fruits, etc. Therefore, it was necessary to package with an impermeable film. For this reason, the air permeability of the sheet (1) has been impaired, and vegetables, fruits, and the like have been spoiled due to accumulation of ethylene gas and the like.
Further, when the sheet (1) is cut, the powdery water-absorbing agent (3) and the gas adsorbent (4) in the sheet (1) spill out, so that the sheet (1) can be cut to an arbitrary size and used. Did not.

Further, as another freshness maintaining sheet, Japanese Patent Application Laid-Open No. 55-132754
Is described in Japanese Patent Application Publication No.

As shown in FIG. 5, the sheet (10) is a fiber sheet obtained by mixing a synthetic fiber such as a polyvinyl alcohol fiber with a super absorbent fiber, and the super absorbent fiber contained in the sheet (10). However, water generated from vegetables, fruits, etc. is absorbed to prevent stuffiness due to excessive humidity and water scorching of vegetables, fruits, etc. Since the sheet (10) is composed of superabsorbent fibers and synthetic fibers, the sheet (10) can be cut to any size to wrap vegetables, fruits and the like when used.

(Problems to be Solved by the Invention) However, since this sheet is composed of superabsorbent fibers and synthetic fibers, water generated from vegetables, fruits, etc., is once stored in the superabsorbent fibers contained in the sheet. Although water was absorbed, it was not retained in the sheet and evaporated immediately through the sheet, making it impossible to maintain appropriate humidity of vegetables, fruits and the like in the sheet. Further, when water generated from vegetables, fruits, and the like is absorbed by the superabsorbent fibers contained in the sheet, when the sheet is subjected to pressure, the absorbed water may leach from the sheet. For this reason, even if this sheet is used, it is necessary to maintain an appropriate humidity of vegetables and fruits, and to cover the sheet with a water-impermeable film in order to prevent leaching of water when absorbing water. As a result, the air permeability of the sheet was impaired by the film, ethylene gas and the like stayed there, causing decay of vegetables and fruits.

The present invention has been made in view of such problems,
It is an object of the present invention to provide a freshness maintaining sheet capable of adjusting the water content of the sheet alone.

(Means for Solving the Problems) That is, the invention according to claim 1 includes an outer layer made of a microporous nonwoven fabric formed by heat fusion of heat fusion fibers,
A freshness maintaining sheet in which an intermediate layer containing superabsorbent fibers and an inner layer made of a water-permeable nonwoven fabric in which fibers are bonded by heat-fusible fibers are integrated.

The invention according to claim 2 is a freshness maintaining sheet, wherein the intermediate layer contains hydrophilic fibers.

The invention according to claim 3 is a freshness maintaining sheet, wherein the intermediate layer contains high crimped fibers.

According to a fourth aspect of the present invention, there is provided a freshness maintaining sheet wherein an outer layer, an inner layer, and an intermediate layer are needled and integrated.

(Operation of the Invention) Therefore, in the freshness retaining sheet according to claim 1,
When wrapping vegetables, fruits, etc. with the freshness holding sheet,
Excess water evaporating from vegetables, fruits and the like permeates through the inner layer where the fibers are bonded by the heat-fusible fibers, and is absorbed by the superabsorbent fibers of the intermediate layer. At this time, the permeation of water is prevented by the microporous nonwoven fabric, which is formed of heat-fusible fibers in the outer layer and has a large number of pores substantially permeable to gas, and evaporates from vegetables and fruits. The surplus water thus collected is held in the freshness holding sheet. Conversely, as the drying of the vegetables, fruits, etc. wrapped in the freshness maintaining sheet progresses, the moisture absorbed in the middle layer returns through the inner layer, and the moisture is supplied to the vegetables, fruits, etc. I have. In addition, gas such as ethylene gas generated from vegetables, fruits and the like in the freshness retaining sheet is released to the outside of the freshness retaining sheet through the holes of the microporous nonwoven fabric formed of the heat-fusible fibers formed in the outer layer. It is supposed to be.

Further, in the freshness retaining sheet according to the second aspect, the water absorbed along the hydrophilic fibers contained in the intermediate layer is diffused throughout the intermediate layer.

In the freshness retaining sheet according to the third aspect, the highly crimped fibers contained in the intermediate layer further enhance the cushioning properties of the intermediate layer.

(Embodiment) Hereinafter, a freshness maintaining sheet of the present invention will be described in detail according to one embodiment shown in the drawings.

FIG. 1 is a perspective view showing an embodiment of the freshness holding sheet of the present invention, FIG. 2 is an enlarged sectional view schematically showing the freshness holding sheet of the present invention, and FIG. 3 is another example of the present invention. FIG. 2 is an enlarged sectional view schematically showing

As shown in FIGS. 1 and 2, the freshness maintaining sheet (11) of the present invention comprises an outer layer (12), an intermediate layer (13) and an inner layer (14).
It is composed of

The outer layer (12) is made of a heat-fusible fiber alone or in the form of a sheet with hydrophobic fibers added thereto by a conventional method, and is manufactured to a predetermined volume. It is a microporous nonwoven fabric to which the fusible fibers are thermally fused. The content of the heat-fusible fiber in the outer layer (12) is 50%
To 100%, preferably 80% to 100%, and the remainder other than 100% contains hydrophobic fibers for the purpose of suppressing water permeation. As the outer layer (12), a web is formed from a heat-fusible fiber such as a polyethylene fiber, a low-melting polyester fiber, or a conjugate fiber composed of a polyethylene component and a polypropylene component, and the web is formed with a binder such as an acrylic binder. A sheet is formed by bonding and heat pressing to form a sheet, or a web is formed by mixing hydrophobic fibers such as polyester fibers with a heat-fusible fiber, and the fibers are bonded with a binder, and then heated and pressed to form a sheet. And the like. The bonding of the web may be performed using the heat-fusible fibers forming the microporous nonwoven fabric as a binder. The microporous non-woven fabric formed when the sheet is formed by hot pressing is a dense and thin non-woven fabric formed by heat-sealing the heat-fusible fibers, and a large number of the size substantially allowing only gas to pass through. A hole is formed.
For this reason, the outer layer (12) can freely transmit gas such as ethylene gas, but hardly transmits moisture. Since the microporous nonwoven fabric is made of molten heat-fusible fibers, the size and area of the pores can be freely set by appropriately changing the content of the heat-fusible fibers and the melting temperature. Accordingly, the moisture permeability and the water permeability of the outer layer (12) can be selectively set. The content of the heat-fusible fiber and the heating temperature in the outer layer (12) need to be appropriately determined in consideration of the use state and shape of the freshness maintaining sheet (11). This means that if the content of the heat-fusible fiber is 100%, heating at an excessively high temperature will increase the amount of the heat-fusible fiber melted by heating, and the outer layer (12) will be too stiff. On the contrary, when the content is less than 50%, the amount of the heat-fusible fiber which is melted by heating is reduced, and the moisture easily penetrates. This is because of the disadvantage. In order to further suppress the permeation of water, it is preferable to use a fiber which has been subjected to a hydrophobic treatment with a hydrophobic oil agent for the outer layer (12). May be applied. An intermediate layer (13) is laminated inside the outer layer (12).

The intermediate layer (13) is a fiber layer made of a sheet of a superabsorbent fiber that absorbs excess water from vegetables, fruits, etc. by a conventional method alone or in a state where hydrophilic fibers are added, and manufactured in a predetermined volume. It is. The content of the superabsorbent fibers in the intermediate layer (13) is 10% to 100%, preferably 50% to 100%, and the balance other than 100% contains hydrophilic fibers. As the intermediate layer (13), fibers obtained by cross-linking acrylate / acrylamide copolymer with acrylic fibers,
This is a fiber that has been given high water absorbency by modifying any of CMC rayon fibers, and has a water absorption capacity of 25 with respect to pure water.
As a preferred example, a web is formed from a superabsorbent fiber that is twice or more in size, and the web is formed by bonding each fiber with a binder such as an acrylic binder and heating and pressing to form a sheet. In addition, if hydrophilic fibers such as rayon and cotton are mixed with the highly water-absorbent fibers as described in claim 2, the absorbed water is mixed along the hydrophilic fibers contained in the intermediate layer (13). Since it is diffused throughout the layer (13), spot-like absorption of water can be avoided as in the case of only the superabsorbent fibers. Further, by adding a hydrophilic fiber to the superabsorbent fiber and further adding a pulp or a hydrophobic fiber, or mixing a highly crimped fiber such as a highly crimped polyester fiber with the superabsorbent fiber as described in claim 3. By doing so, the water is more efficiently diffused throughout the intermediate layer (13). An inner layer (14) is laminated inside the intermediate layer (13), that is, on the side of vegetables, fruits and the like.

The inner layer (14) is an intermediate layer (13) together with the outer layer (12).
This is a water-permeable fiber layer that covers the surface of the sheet and is formed into a sheet by a conventional method in a state containing heat-fusible fibers and manufactured to a predetermined volume. In the inner layer (14), the fibers constituting the inner layer (14) are bonded by the melted heat-fusible fibers, so that the strength of the inner layer (14) is improved and the fibers are prevented from coming off. The inner layer (14) also prevents the gel-like substance generated by the water absorption of the superabsorbent fibers from coming into contact with vegetables and fruits, thereby reducing the commercial value. Inner layer (14)
The content of the heat-fusible fiber in the above is 10% to 50%, preferably 20% to 50%, and the fiber contained in the remainder is said to be compatible with excess water evaporated from vegetables, fruits, etc. From the viewpoint, hydrophilic fibers are preferred. However, hydrophobic fibers can be suitably used as long as they have been subjected to a hydrophilizing treatment with a hydrophilic oil agent. By mixing high crimped fibers such as high crimped polyester fibers with the fibers constituting the inner layer (14), an inner layer (14) having a high bulkiness can be obtained. The obtained freshness maintaining sheet (11) has a rich cushioning property, and when wrapping and using vegetables, fruits, etc., it is possible to eliminate pain of vegetables, fruits, etc. occurring during transportation.

As a method of integrating each of the fiber layers of the outer layer (12), the intermediate layer (13), and the inner layer (14) described above, any conventionally known method may be used. In order to make each fiber layer difficult to peel off, the intermediate layer (13), the outer layer (12), and the inner layer (14) were overlapped and needled to integrate the respective fiber layers. The present invention is not limited to this, and an adhesive may be interposed between the respective fiber layers, and the respective fiber layers may be bonded and integrated with the adhesive. Alternatively, a web or a web-like sheet made of heat-bondable fibers may be laminated on the surface on which the respective fiber layers are overlapped, and the respective fiber layers may be heated and fused by the sheet.

As shown in FIG. 3, a perforated film made of a synthetic resin such as low-density polyethylene, high-density polyethylene, polypropylene, and soft vinyl chloride resin is provided inside the freshness maintaining sheet (11) of the present invention described above. If 15) is applied, the inner surface of the freshness preserving sheet (11) becomes smooth, and when wrapping vegetables, fruits, etc., fibers and gel-like substances adhere to the vegetables, fruits, etc., reducing the commercial value. Lowering can be more completely prevented.

Next, how to use the freshness maintaining sheet of the present invention described above will be described.

As shown in FIGS. 1 and 2, when vegetables, fruits, and the like are wrapped by the freshness retaining sheet (11) of the present invention, when the humidity in the freshness retaining sheet (11) becomes about 85% or more, heat is applied. Inner layer (1
Excess water evaporating from 4) from vegetables, fruits and the like permeates and is absorbed by the superabsorbent fibers of the intermediate layer (13). At this time, the permeation of water is prevented by a microporous nonwoven fabric formed of heat-fusible fibers of the outer layer (12) and formed with a large number of pores substantially permeable to gas, thereby preventing the permeation of water, Excess water evaporating from the sheet or the like is held in the freshness holding sheet. Conversely, when the vegetables, fruits, etc. wrapped in the freshness maintaining sheet (11) dries and the humidity in the freshness maintaining sheet (11) becomes about 85% or less, the moisture is absorbed by the intermediate layer (13). Moisture is inner layer (14)
, And returns to supply water to vegetables, fruits and the like. Therefore, the freshness holding sheet (11)
It is suitable as an inner packaging material for a container for transporting painful fruits such as melon, watermelon, and grapes, or as a storage pack for storing vegetables and the like in a refrigerator.

(Effect of the Invention) As described in detail above, in the freshness retaining sheet according to the first aspect, when vegetables, fruits, and the like are wrapped by the freshness retaining sheet, the heat-fusible fibers melted by heat and melted. Surplus water evaporating from vegetables, fruits and the like permeates through the inner layer to which is bonded, and is absorbed by the superabsorbent fibers of the intermediate layer. At this time, the permeation of water is prevented by the microporous nonwoven fabric, which is formed of heat-fusible fibers in the outer layer and has a large number of pores substantially permeable to gas, and evaporates from vegetables and fruits. The surplus water thus collected is held in the freshness holding sheet. Conversely, as the drying of the vegetables, fruits, etc. wrapped in the freshness maintaining sheet progresses, the moisture absorbed in the middle layer returns through the inner layer, and the moisture is supplied to the vegetables, fruits, etc. I have. For this reason,
Water can be adjusted by the freshness maintaining sheet alone,
There is no need to package with a water-impermeable film as shown in the conventional example, and a simpler structure can be achieved.
In addition, gas such as ethylene gas generated from vegetables, fruits and the like wrapped in the freshness holding sheet passes through the holes of the microporous nonwoven fabric formed of the molten heat-fusible fiber formed in the outer layer, and is discharged outside the freshness holding sheet. To be released. Therefore, vegetables, fruits, and the like do not rot due to stagnation of gas such as ethylene gas. Further, in the freshness holding sheet according to the first aspect, even if vegetables, fruits, etc. wrapped by shaking or vibration during transportation collide or slide, the freshness holding sheet is made of fibers. As a result, it has cushioning properties, softens the impact, and makes it difficult for vegetables, fruits and the like to be damaged. Further, in the freshness retaining sheet according to the first aspect, since water is absorbed by the highly water-absorbing fibers contained in the intermediate layer, the sheet is cut into a desired size and shape freely. Can be used.

According to the freshness retaining sheet of the second aspect, the absorbed water diffuses throughout the intermediate layer along the hydrophilic fibers contained in the intermediate layer, so that the freshness retaining sheet by spot absorption of water. Can be prevented from being partially expanded.

Further, when the intermediate layer contains high crimped fibers as in the freshness retaining sheet according to claim 3, the cushioning property of the high crimped fibers is added to the intermediate layer, and the cushioning property of the freshness retaining sheet is further improved. Increase.

Further, in the freshness retaining sheet according to the fourth aspect, since the outer layer, the intermediate layer, and the inner layer are needled and integrated, each layer is more difficult to peel off.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the freshness holding sheet of the present invention, FIG. 2 is an enlarged sectional view schematically showing the freshness holding sheet of the present invention, and FIG. 3 is another example of the present invention. FIG. 4 is a partially cutaway perspective view showing a conventional freshness maintaining sheet, and FIG. 5 is a perspective view showing another conventional freshness maintaining sheet. Description of symbols 12: outer layer, 13: middle layer, 14: inner layer.

Claims (4)

(57) [Claims] An outer layer made of a microporous nonwoven fabric formed by heat fusion of heat fusible fibers, an intermediate layer containing superabsorbent fibers, and fibers are bonded by heat fusible fibers. A freshness maintaining sheet in which an inner layer made of a water-permeable nonwoven fabric is integrated. 2. The freshness maintaining sheet according to claim 1, wherein the intermediate layer contains a hydrophilic fiber. 3. The freshness retaining sheet according to claim 1, wherein the intermediate layer contains high crimped fibers. 4. An outer layer, an inner layer and an intermediate layer are needled and integrated by needling.
The freshness retaining sheet as described.