JPH02312578A - Water absorbent sheet and cold insulation of fresh food using the same - Google Patents

Abstract

PURPOSE:To obtain the subject sheet with high water absorbency by sandwiching a highly water absorbent resin between a newspaper and a toilet tissue into a sheet-like product and by encapsulating it into a cylindrical form made up of a water-penetrable nonwoven fabric backed with a water-resistant resin film. CONSTITUTION:Firstly, a sheet-like product B is prepared by sandwiching a highly water absorbent resin between a newspaper and a toilet tissue followed by integration through embossing process. Thence, this product B is encapsulated into a cylindrical form A made up of a water-penetrable nonwoven fabric 3 having also a water-repellency backed with a water-resistant, liquid leakproof resin film 2, thus obtaining the objective water-absorptive sheet 1. The present sheet is encapsulated, together with ice and fresh foods, into a water-resistant container; thereby, said foods can be prevented at ice temperature for a long period without sliminess migration thereinto.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a water-absorbing sheet used for ice-temperature refrigeration of perishable foods and for freezing-temperature transportation of perishable foods.

This water absorbent sheet can also be used as a disposable diaper or sanitary napkin. Furthermore, this water-absorbing sheet can be made to absorb water and frozen, which can also be used as a cold storage agent.

The fish were stored together with ice in a foamed polystyrene shell box, and a lid made of foamed boristyrene was fitted into the shell box before being transported from the fishing port to the place of consumption at ice temperature.

There are two types of such insulating meat boxes: those with drainage holes at the bottom and those without drainage holes.In the case of the former meat box, when the ice melts, water flows through the drainage holes into the meat box. The quality of the fresh fish does not deteriorate because it leaks outside, but there are drawbacks such as the smell of the spilled fish and the smell of fish lingering on the transportation vehicle, and the transportation vehicle being corroded by the salt contained in the water. .

In the case of the latter meat box, the escape of fish odor outside the box and corrosion of the transport vehicle are prevented, but when the ice melts, water stays inside the meat box, which deteriorates the quality of fresh fish.

On the other hand, when fresh fruits and vegetables such as asparagus, broccoli, and strawberries are stored or transported at room temperature, they breathe, and the heat they emit from breathing increases the temperature inside the storage room, causing them to age. However, in some cases, the ripeness of the stored food may deteriorate, resulting in poor taste, spoilage, and deterioration.In order to prevent these problems, the temperature in the storage room must be kept at a low temperature that does not reduce the freshness of the stored items. It is necessary to keep it cool at +5°C, and many proposals have been made for cold boxes used for storing and transporting it. For example, as disclosed in Japanese Utility Model Application No. 57-172752 and Japanese Utility Model Application Publication No. 58-52144, a box made of expanded polystyrene resin is equipped with an inner lid that can contain a cold storage agent such as dry ice or ice. A heat-insulating cold box is known, which includes a body and an outer lid made of expanded polystyrene resin.

When using ice as a cold storage agent in this cold box,
Ice is stored in polyethylene bags to prevent water from melting from coming into direct contact with fresh fruits and vegetables.

These cold storage boxes require an inner lid to separate cold storage agents such as dry ice and ice packs from stored perishable foods.
It is troublesome to handle the removal.

An attempt was made to mix superabsorbent resin powder, which absorbs 20 to 1600 g of water per gram, with ice in an ice-temperature refrigeration system to absorb melted water and prevent food from losing freshness. However, it was not put to practical use because slimy superabsorbent resin lumps that absorbed water and became gel-like adhered to foods.

Furthermore, it is proposed that food be transported by making a sheet of thermoplastic resin containing super absorbent resin powder absorb water, freezing it, and placing it in a foamed polystyrene insulation box as a cold storage agent. It was done.

Even in this method, the surface of the sheet-like cold storage agent absorbs water and becomes slimy, so it was necessary to isolate the cold storage agent from food and place it in a container.

The reason why the gel-like substance of the super absorbent resin that has absorbed water becomes slimy is presumed to be because the super absorbent resin is made by the following manufacturing method and becomes an alkali salt (
"Polymer Processing", No. 9, 1984, pp. 32-38, JP-A-53-80493, JP-A-53-46199, JP-A-60-6236).

(Speed "F Mari Roku++ c"qcf3 〒 10
[Problems to be Solved by the Invention] The object of the present invention is to provide a water-absorbing sheet that has excellent water-absorbing properties and has a structure that prevents sliminess from coming into contact with fresh foods even when water is absorbed.

The present invention also provides this water-absorbent sheet 1- in an ice-temperature refrigeration system 1.
The purpose of the present invention is to provide an ice-temperature refrigeration system for fresh foods that can maintain an ice-temperature effect for a long time when used in .

[Specific means to solve the problem]

In the present invention, in order to create a structure in which the slime of the superabsorbent resin gel does not come into contact with food, the superabsorbent resin is sealed in a cylindrical body, and the water absorbent gel of the superabsorbent resin is used with Shinkai paper. The problem of sliminess was solved by covering it with a water-repellent non-woven fabric such as rayon.

In addition, it is easy to hold the super absorbent resin powder, and so that the super absorbent resin can fully demonstrate its water absorption performance. Shinkai paper, which does not get wet, and toilet vapor, which easily dissolves water, were embossed to form a sheet.

That is, the present invention provides newsprint and 1-ylene I in a cylindrical body (A) composed of a liquid-leakproof backing made of a water-resistant resin film and a surface made of a water-repellent water-permeable nonwoven fabric.・Water absorbency characterized by having a sheet-like material (B) in which a super absorbent resin is sandwiched between the paper and embossed, and these three materials are integrated, enclosed in the cylindrical structure. It provides sheets.

The second aspect of the present invention is that a cylindrical body (A) composed of a liquid leakage-proof back body made of a water-resistant resin film and a surface body made of a water-permeable nonwoven fabric having water repellency is provided with newsprint and l. A sheet-like product that integrates these champions by sandwiching a super absorbent resin between paper and embossed paper (
The present invention provides a method for freezing fresh food products, characterized in that a water-absorbent sheet having a structure in which B) is sealed inside the tube is sealed together with ice and fresh food products in a water-resistant container.

Hereinafter, the present invention will be explained using a concave surface.

FIG. 1 is a perspective view of the water absorbent sheet 1 of the present invention, and FIG. 2 is a sectional view taken along line I-1. The cylindrical body A includes a liquid-leakproof and water-resistant resin film 2 made of a thermoplastic resin such as polyethylene, polypropylene, polyvinyl chloride, or polyethylene terephthalate, and a water-permeable resin film 2 made of rayon, polyamide, polyester, polypropylene, polyethylene, etc. 1. It is formed by bonding the end portions 4, 4, 4', 4' of the water-repellent nonwoven fabric 3 using heat sealing or an adhesive.

At the end 4', as shown in FIG. 3, the liquid-leakproof resin film 2 forming the back surface is folded back and placed on the nonwoven fabric 3 of the front surface, together with the enclosed sheet material B. The sheet-like material B is glued to prevent the sheet-like material B from freely moving inside the cylindrical body. The thickness of film 2 is 10
~150 micron, the basis weight of nonwoven fabric 3 is 1~30/rl
(is normal.

The highly water-absorbent sheet material B enclosed in the cylindrical body A is made of, for example, a highly water-absorbent resin powder or fibrous material 5 with a particle size of 10 to 200 microns that absorbs 450 to 2000 g of water per 1 g of resin powder. , a laminate sandwiched between Shinkai paper 6 and water-soluble toilet paper 7 is embossed to make it easier to carry.

Newsprint is uniform, has adequate strength, and is insoluble in water. Shinkai Paper is made using ground wood pulp as its main raw material, which is mixed with chemical pulp. Newsprint pulp used in Japan includes softwood groundwood pulp, hardwood semi-chemical pulp, hardwood chemical ground pulp, hardwood and softwood refined ground pulp, unbleached softwood sulfite pulp, semi-grained or bleached kraft pulp, and the like.

The standard for newsprint is JIS P4O10-1964.
The quality according to the standards is as follows.

(1) Thickness 0.080 mm or more (2) Weight 5
2±2g/n ((3) Tensile strength (Longitudinal H, 8kg or more (4) Elongation
(Vertical) 0.7% or more (5) Tear strength (Horizontal) 20.0g or more (6) Smoothness
There should be little difference between the front and back. The figures depend on the agreement between the parties.

(7) Oil absorption: Based on agreement between the parties.

(8) Whiteness Whiteness must comply with both of the following regulations.

When using a blue filter: 45% or more When using a border color filter: 57% or more (9) Opacity 89
% or more of newsprint is used to prevent the gel of the super absorbent resin 5 that has expanded in volume by absorbing water from penetrating the nonwoven fabric of the surface body 3 of the cylindrical body A, and to prevent the sliminess of the gel from transferring to the nonwoven fabric 3. Acts as a membrane. Therefore, among other types of paper, newsprint was used, which is strong enough to not break even when subjected to high-speed rotary presses, and which does not tear even when it absorbs water.

The toilet paper 7 has appropriate strength and flexibility,
It dissolves easily in water. The raw material is mainly waste paper, mixed with some pulp, or mainly chemical pulp with the addition of ground wood pulp, and is JIS P4501.
-1962 quality specifications are as follows.

(1) Weighing 1.5 g/bo or more (2
) bursting strength 10 sheets) 1.0kg/c or more (3
) Whiteness: 60% or more (4) Water absorption: 20 n+m or more The toilet paper 7 is loosened by water so that the super absorbent powder 5 can fully demonstrate its water absorption performance, and most of it dissolves in water as the gel volume increases. . Since the cylindrical body A is flexible, and the volume of the cylindrical body is sufficient to accommodate the increased volume of the superabsorbent resin gel, the superabsorbent resin can sufficiently exhibit its water absorption function.

It is preferable that the super-absorbent resin is in the form of powder or fibers, since this can fully demonstrate its water-absorbing performance (absorbing 600-2000 g of water per 1 g of resin).
% by weight and extruded into a film with a slightly reduced water absorption of 20 to 600 g/g.

The embossing serves to prevent the superabsorbent resin powder 5 from falling off from the water-absorbent sheet B, and also to expand the surface area of the water-absorbent sheet B and speed up the water absorption rate. The embossed pattern may be a lattice pattern, a tie pattern, or a cross weave pattern.

The water absorption amount of the sheet-like material B varies depending on the shape of the superabsorbent resin (powder, texture, sheet), but it is 5 to 5 per Inτ.
Absorbs 100ff of water.

(Example) Next, a method of transporting fresh fish at freezing temperature using this water-absorbing sheet will be described.

(Example 1) As shown in Figure 4, density 35g/p, inner dimension 205+
m++X27 On+InX 135m, volume 7j2.
The water absorbent sheet 1 of the present invention is placed on the inner bottom of a fish box 8 made of polystyrene resin foam with a wall thickness of 2 mm, with the nonwoven fabric side 3 facing the lid 9 side, in other words, the resin film J, and the 2 side facing the bottom side of the fish box. I interpolated it so that it faced. This water absorbent sheet 1 has a weight of 52 g/
The amount of water absorption is 1. ．． 680g/g, 120g of super absorbent resin powder made of glycidyl ether crosslinked product of sodium polyacrylate with a particle size of 36 microns.
/rrf, and the weight is 22 on top of this powder.
g/nK toilet paper, with a cross-woven pattern of 41 mm, so that it can be carried as a sheet-like product, with a width of 1.
It was cut into a rectangle with a diameter of 70 mm and a length of 300 mm.

This cut water-absorbent sheet material B was cut into a hole with a wall thickness of 40 microns, a width of 210 mm, and a length of 350 mm.
'.

Place a film 2 of pyrene (ethylene, propylene block copolymer) in the center so that the toilet paper side is on the film side, and then place a sheet of 30
g7rrr, width 210m+n, length 300+11111
A rayon nonwoven fabric 3 is placed, and the film 2 is folded back to the nonwoven fabric 3'' by 25 mm at each end in the length direction, and the four peripheral edges 4.4 of this laminate are folded.

4'. A water-absorbent sheet 1 (not shown in FIG. 1) in which a sheet-like material B is enclosed within a cylindrical body Δ made of a film 2 and a nonwoven fabric 3 is produced by heat-sealing a sheet of 4' in width 8. This water-absorbing sheet can absorb up to 60 f of water per bottle.

Next, on the water absorbent sheet 10 inserted into this fish box -
1. 11 pieces of ice at 7°C, then 10 pieces of fresh fish, and then
After filling the fish box with ice at 17°C,
Box made of foam (FJ 20 mm, density 35 g/p
) to create a sealed structure (the amount of ice in the fish box is 1.1
kg).

This sealed fish box was left in a constant temperature room at 20°C, and the change in temperature inside the fish box over time was investigated, as shown in Figure 4.

That is, the temperature inside the fish box exceeded O'C after 27 hours. In addition, the temperature inside the fish box after 42 hours was 1
Although the temperature was 4°C, there was no melted ice water found in the fish box; all of the water was absorbed by the water absorption sheet H1, the superabsorbent resin gelled to a thickness of 2 mm, and the toilet paper was It was melting.

In addition, the water-absorbing gel was encapsulated in the cylindrical body A made of a nonwoven fabric and a film, which had a gel body attached to newsprint, and there was no sliminess on the surface of the nonwoven fabric 3.

(Reference example) The temperature change over time in the fish box was determined by Δ[11] in the same manner as in the example except that the water absorbent sheet was not inserted into the fish box, and the result was as shown in Figure 4. .

(Example 2) After absorbing water, one or more of the water-absorbing sheets of the present invention produced in Example 1 were placed in a refrigerated garage at ~20'C, frozen, and used as a cold storage agent.

These cold storage agents did not adhere to each other due to the resin film 2 of the cylindrical body A, and were easy to handle. The surface temperature of this cool storage agent was 0.5°C.

In a warehouse at 10°C, put two 500g pieces of this cold storage agent into a cardboard box with an inner volume of 7P and an aluminum foil attached to the inside, insert bok choy, and put one of the cardboard boxes.
- The flap of the lid was sealed with adhesive tape. This was stored in a constant temperature room at 18°C.

After 30 minutes, the temperature inside the corrugated pole was 6°C.

The temperature inside the cardboard box after 24 hours was 6°C, and the temperature after 30 hours was 7°C. No frost damage was observed on the bok choy.

(Comparative example) Two bags of a cold storage agent (500 g) packaged in a commercially available plastic bag were placed in a -IO°C freezer, kept for the same time as the one in Example 2, frozen, and used as a cold storage agent. . The surface temperature of the plastic bag was -1°C.

Hereinafter, when bok choy was kept cold in the same manner as in Example 2,
The temperature inside the cardboard after 30 minutes is 4°C, the temperature inside the cardboard after 5 hours is 6°C, the temperature after 24 hours is 8°C, and the temperature inside the cardboard after 130 hours is 8°C. The temperature was 10°C.

The parts of the bok choy that were in contact with the cold storage agent were slightly damaged by frost damage.

(Other uses) The water-absorbing sheet of the present invention can be used not only as a water-absorbing agent in the above-mentioned freezing temperature transportation system and as a cold storage agent, but also for disposable diapers, sanitary napkins, and the like.

[Effects] The water-absorbing sheet of the present invention can prevent the slime of the absorbed superabsorbent resin gel from being transferred using newsprint and nonwoven fabric, and can prevent the slime of fresh foods from transferring. In addition, the cold storage effect and cold storage effect can be maintained for a longer period of time than conventional cold storage agents and ice.

Furthermore, when used as a cold storage agent by absorbing water and freezing it,
It has the advantage of not causing freezing damage even if it comes into contact with fresh food.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the water absorbent sheet I of the present invention, Fig. 2 is a sectional view taken along line I-1 of the water absorbent sheet 1 shown in Fig. 1, and Fig. 3 is a welded portion of the end of the water absorbent sheet. ■-■ Cross-sectional view, Figure 4 is a cross-sectional view showing ice-cold storage of fresh fish, and Figure 5 shows cases in which the water-absorbing sheet of the present invention and ice are used as a refrigerant in an ice-cold storage system, and cases in which ice alone is used. It is a figure which shows the change in temperature in a fish box over time when it is used.

Claims (1)

[Claims] 1). A super absorbent resin is placed between newsprint and toilet paper in a cylindrical body (A) that is composed of a liquid-leakproof backing made of a water-resistant resin film and a surface made of a water-permeable nonwoven fabric with water repellency. A water-absorbing sheet characterized in that a sheet-like material (B) in which these three materials are sandwiched and embossed to integrate these three materials is enclosed in the cylindrical material. 2). A super absorbent resin is placed between newsprint and toilet paper in a cylindrical body (A) that is composed of a liquid-leakproof backing made of a water-resistant resin film and a surface made of a water-permeable nonwoven fabric with water repellency. A water-absorbent sheet having a structure in which a sheet-like material (B) in which these three materials are sandwiched and embossed to integrate these three materials is enclosed in the cylindrical material is enclosed in a water-resistant container together with ice and fresh food. A method for keeping fresh food cold.