JPH07323498A - Water absorbing sheet - Google Patents

Abstract

PURPOSE:To provide a water absorbing sheet absorbing a proper amt. of an excessive moisture cell fluid, not excessively dried or deformed and preventing the lowering of food taste when perishable foods are preserved generated because of the insufficient absorption of water by specifying the area ratio of the protruding parts of a perforated film. CONSTITUTION:A hydrophobic perforated film 2 pref. has a corrugated shape and the area of the protruding parts thereof is 10-50% of the total area thereof. When the area of the protruding parts is below 10%, the film 2 generates a deformation flaw in the case of a soft material and, when the area of the protruding parts exceeds 50%, liquid drainage and the keeping of freshness are deteriorated. More pref., the area of the protruding parts is 20-40%. The perforated film 2 and a water absorbing layer 1 may be formed into a corrugated shape in a closely bonded state but it is pref. that only the perforated film has a corrugated shape and the water absorbing layer 1 and the perforated film 2 are partially bonded because the return of a liquid is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fresh food drip sheet and the like.

[0002]

2. Description of the Related Art A water-absorbent laminate using a porous sheet is described in, for example, Japanese Patent Publication No. 1-49112. This laminated body contains a super absorbent polymer powder in the water absorbing layer. Therefore, it is said that the diameter of the pores should be smaller than the particle diameter of the pore-absorbing polymer so that the superabsorbent polymer does not fall from the pores, and a porous sheet such as nonwoven fabric is used.

However, when such a flat non-woven fabric is used as a porous sheet, the cell liquid coming out of the fresh food product is in contact with the fresh food product even if it is absorbed by the water absorbing layer. In order to maintain the fineness, it is preferable that the fresh food product and the cell liquid discharged from it not come into contact with each other as much as possible. On the other hand, when the water-absorbing layer has a large water-absorbing capacity, it tends to be dry when the contact area with fresh food is large, and the commercial value is significantly impaired.

[0004]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a moderate water-absorbing sheet in which the cell liquid discharged from a fresh food product does not touch the fresh food product as much as possible and the contact area with the fresh food product is not too large. It is in.

[0005]

Means for Solving the Problems The present inventors have studied the pore size and the aperture ratio of a porous film, studied the contact area of the film, the material of the water absorbing layer, and the lamination method, and completed the present invention. I arrived.

The water-absorbent sheet of the present invention has a laminated structure of a hydrophobic concave-convex porous film and a water-absorbing layer, and at least the area of the convex portions of the porous film is 10% or more of the total area,
It is characterized by being 50% or less.

The porous film used in the water absorbent sheet of the present invention may be a commonly used film. For example, there are polyethylene, polypropylene, polyester, nylon, polyvinylidene chloride, polyvinyl chloride, cellophane, and the like. Further, these may be laminated, and polyvinyl alcohol or the like may be sandwiched between them. Further, it may be laminated with a metal film such as aluminum.

The pore size of the porous film used in the present invention is 1
0 to 500 μm is preferable. More preferably 40 to 20
It is 0 μm. If the pore size is too small, the water absorption rate will be too small, and if the pore size is too large, the pore shape may appear in the fresh food products. The method for making holes in the film is not particularly limited. A hole may be formed with a hot needle or electric discharge machining may be performed. Further, by appropriately selecting the shape of the holes and the sizes of the inlet and the outlet, it is possible to prevent the absorbed liquid from flowing back.

The material of the film may be appropriately selected, but cellophane, which is easily wet with water, is not very preferable. When heating a large amount of oil in a microwave oven, it is preferable to use a polyvinylidene chloride film. Strength,
It is advisable to select the material and film thickness in consideration of cost and other factors.

The shape of the hydrophobic porous film used in the present invention is such that the area of the convex portion is 10% or more and 50% or less of the entire area, and the porous film is preferably wavy. A mountain shape is also acceptable. If the area of the convex portion is less than 10%, the soft material may be deformed. Also, when the area of the convex portion exceeds 50%, liquid drainage becomes worse,
Freshness retention is poor. More preferably, the convex area is 20
% Or more and 40% or less.

The area of the convex portion in the present invention means an area where the depth of the convex portion is within 1 mm from the water absorbing surface. Therefore, the area with the radius and the area with minute irregularities are also included in the area of this convex portion (see FIGS. 1 and 2).

Further, the porous film and the water absorbing layer adhere to each other,
Although it may have the same corrugated plate shape, it is preferable that only the porous film has a corrugated plate shape and the water-absorbing layer and the porous film are partially adhered to each other because liquid return is small.

Since the water absorbing layer used in the present invention has an appropriate water absorbing rate, it is necessary to maintain an appropriate water absorbing amount. It is preferable to absorb at least 300% by weight of artificial seawater. Fresh food products are often body fluids with dissolved salts, rather than pure water. Therefore, it is often more practical to measure an appropriate amount of water absorption with artificial seawater. When the water absorption amount is less than 300% by weight, it is necessary to increase the basis weight of the water absorption layer, which increases the cost, and thus the larger water absorption amount is preferable.

The water-absorbing layer used in the present invention includes non-woven fabric, paper and the like, but it is preferable that the water-absorbing layer contains a highly water-absorbing polymer or highly water-absorbing fiber because the amount of water absorption is large. Among them, “Oasis” manufactured by British Technical Absorbent Co., Ltd. is preferred as the highly water-absorbent fiber because of its large water absorption. Superabsorbent polymers are less preferred because they tend to fall off.

The method for producing the non-woven fabric and the paper is not particularly limited. Nonwoven fabrics are manufactured by air-laying, cross-laying, spunbonding, meltblowing, papermaking, etc. In the case of a highly water-absorbent fiber, it can be easily mixed into a non-woven fabric, but in the case of a highly water-absorbent polymer, the air lay method or the coating method is used.

Further, the water absorbent sheet of the present invention may contain an antibacterial agent or an odor preventing agent such as activated carbon particles or activated carbon fibers. Further, coloring, printing or the like may be applied to improve the appearance.

In the present invention, the artificial seawater used for measuring the amount of water absorption was produced by using a commercially available reagent, "Aquamarine" manufactured by Yasu Pharmaceutical Co., Ltd. That is, "Aquamarine"
724 g of agent A and 562 g of agent B were dissolved in 20 liters of ion-exchanged water and used as artificial seawater. The water absorption rate of the water absorption layer was obtained by putting it in a sample tea bag, immersing it in artificial seawater for 3 minutes, and then suspending it, and measuring the weight at which water drops did not fall.

The freshness-retaining effect of fresh food products is about 3% of purple sea urchin eggs (hereinafter abbreviated as "sea urchin") on the water absorbing sheet.
They were arranged so as not to overlap with each other by 0 g, wrapped with a polyvinylidene chloride film, and left at room temperature for 30 minutes. Next -3
The sea urchin was rapidly cooled and frozen at 0 ° C., stored for 24 hours, taken out, and thawed at room temperature.
Moreover, the taste was compared by 10 panelists. The taste of sea urchins is likely to change, and the shape and the like are also likely to change depending on the storage state, so it is easy to compare the effects of the water absorbing sheets. However, the water-absorbent sheet of the present invention can be used not only for water absorption of marine products but also for water absorption of fruits, vegetables and flowers.

[0019]

EFFECTS OF THE INVENTION When the water absorbent sheet of the present invention is used, it absorbs an appropriate amount of excess water (such as cell liquid), so that it does not become overdried or deformed. It is possible to prevent the deterioration of the taste during storage.

[0020]

EXAMPLES Further details will be described in Examples.

Example 1 In a biaxially oriented film of polypropylene, a hole having a thickness of about 120 μm was made from one direction in a film having a thickness of 60 μm by a hot needle, and then processed into a corrugated shape having a pitch of 5 mm and a depth of 4 mm to form a convex shape. A porous film used for the water absorbent sheet of the present invention having a part area of 50% was produced. The holes were opened at a density of 100 holes / cm ² .

Next, a water absorbing layer used in the water absorbing sheet of the present invention was produced from paper. The raw material of this paper is 10 wt% of crushed 9 denier of Oasis, pulp KBNP.
80% by weight was handmade with a rectangular sheet machine according to TAPPI. At the time of papermaking, the pulp was beaten by a conventional method, and papermaking was carried out at a concentration of 0.1% by weight. The basis weight of the obtained paper was 100 g / m ² . The artificial seawater absorption of this paper was 530% by weight.

As the adhesive, a binder having a basis weight of 30 g / m ² made of a nonwoven fabric of a conjugate fiber having a sheath of polyethylene and a core of polyester was used and bonded so that the holes of the porous film were not blocked. The water-absorbent sheet of the present invention was manufactured by lightly pressing the paper on the opposite side of the porous film on which the needle was pierced and the water-absorbing layer at 130 ° C. using this binder and heat-bonding the corrugated recesses.

Sea urchin was placed on this water-absorbent sheet, and the weight before and after quick-freezing and thawing was measured to measure the change in water content. In addition, the taste was compared with that before freezing by a panel of 5 adult male volunteers and 5 female volunteers. For reference, the same test was also performed when sea urchins were placed only on the flat porous film and only the water absorbing layer paper. The evaluation results are shown in Table 1.

[0025]

[Table 1]

Example 2 A water-absorbing sheet No. 1 of the present invention was manufactured in the same manner as in Example 1 by producing a porous film in which the area of the convex portion of the porous film was changed. 4 to 7 and Reference Example No. 8 was manufactured and its performance was evaluated in the same manner as in Example 1 and shown in Table 2. Test N
o. In No. 6, since the area of the convex portion was slightly small, the sea urchin after thawing was slightly wavy. For reference, a water-absorbent sheet having a convex area of 5% was manufactured and tested in the same manner. However, the sea urchin after thawing was clearly wavy, and the appearance at the time of display was deteriorated.

[0027]

[Table 2]

Example 4 Instead of the paper of the water absorbing layer of Example 1, a water absorbing layer having a different water absorption rate of artificial seawater was produced by a conventional method, and the water absorbing sheet of the present invention was produced in the same manner as in Example 1. . Table 3 shows the production conditions of the water absorption layer. Table 4 shows the evaluation results of this water absorbing sheet.

In the air lay method, the oasis is 9 denier and 6
mm, the binder used was 6 mm of 2 denier of conjugate fiber of polyethylene sheath and polypropylene core. In the cross ray method, 51 mm was used for each. Test No.
9 to 12 have a basis weight of 100 g / m ² and a test No. Thirteen
Was manufactured with a basis weight of 50 g / m ² .

[0030]

[Table 3]

[0031]

[Table 4]

[Brief description of drawings]

FIG. 1 is an enlarged view of an example (corrugated) of a water absorbent sheet of the present invention.

FIG. 2 is an enlarged view of an example (mountain type) of the water absorbent sheet of the present invention.

[Explanation of symbols]

 1 Water Absorbing Layer 2 Porous Film 3 Depth 4 Width Corresponding to Entire Unit Area 5 Width Corresponding to Area of Convex 6 Water Absorbing Surface 7 Surface of Convex 8 Surface of Unit Area

Claims (5)

[Claims] 1. A laminated structure of a hydrophobic concavo-convex porous film and a water-absorbent layer, wherein at least the area of the convex portion of the porous film is 10% or more and 50% or less of the entire area. And water absorbent sheet. 2. The water absorbent sheet according to claim 1, wherein the porous film is corrugated. 3. The pore size of the hydrophobic porous film is 10 to 5
The water absorbing sheet according to claim 1 or 2, which has a thickness of 00 μm. 4. The water absorbing layer contains at least 300 artificial seawater.
The water absorbent sheet according to claim 1, wherein the water absorbent sheet absorbs water by weight or more. 5. The water absorbent sheet according to claim 1, wherein the hydrophobic porous film and the water absorbent layer are partially adhered to each other.