JPH08150690A - Food packaging sheet - Google Patents

Abstract

PURPOSE: To provide a food packaging sheet which restrains falling of a water absorber, can be handled easily, and absorbs water in contents having irregular shapes such as fresh fishery product and meat quickly and uniformly. CONSTITUTION: A laminated sheet has a first layer made of paper inside thereof, a second layer made of unwoven cloth layered outside thereof, and a bending resistance of preferably 200-kg. at the most. The first layer has a wet strength of at least 0.10kg/15mm and a water absorbing speed of at least 10mm/sec. The second layer has at least 500g/m<2> and a water absorbing degree of preferably at least 1000wt.%. It is preferable that the second layer has at least 30wt.% of water absorbing fiber or fine grain. The sheet may have further a third layer consisting of non-permeable material arranged outside of the second layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a food packaging material, and more particularly to a water absorbent sheet that promotes the absorption of water by fresh seafood, meat and the like.

[0002]

2. Description of the Related Art A water-absorbing sheet for laying in a food packaging container such as a tray to absorb the drip of fresh food such as meat and fish and to absorb the dew condensation generated from the food has already been disclosed in Japanese Utility Model Publication No. 1-163123. Proposed in the gazette. This water-absorbing sheet has a three-layer structure, the second intermediate layer is a water-absorbing layer, has a water absorption amount of 3 times or more of its own weight, and has a water-absorbing fiber content of 5 to 95% by weight and 95- It consists of 5% by weight of heat-bondable fibers. The first layer and the third layer are protective sheets. Nonwoven fabrics and knitted fabrics made of heat-adhesive fibers are said to be suitable for the first layer, and a film is used for the third layer.

[0003] Commercially available heat fusion fibers are essentially hydrophilic polymers such as polyester, polyethylene and polypropylene, and have poor hydrophilicity. Therefore, in the water absorbing sheet of the above proposal, the absorbed water is absorbed in the second layer,
It seems that they are hoping that nothing will remain in the layer.

However, in order to promote the absorption of water in the contents such as fresh seafood and meat, the first layer needs to be immediately permeable to water. In addition, even if these contents have irregularities, it is necessary to absorb water at the contacting portion, diffuse in the first layer, and transfer to the second layer. On the contrary, the water absorbing sheet proposed above is not suitable for promoting water absorption since the first layer is hydrophobic.

On the other hand, a water-absorbent nonwoven fabric using a water-absorbent polymer is described in, for example, Japanese Patent Publication No. 1-49112. It is said that this water-absorbent nonwoven fabric is formed by laminating porous films so as to prevent the contained water-absorbent polymer from falling off, and the pore size of the pores should be smaller than the particle size of the water-absorbent polymer. As described above, since the water-absorbent polymer is easily removed from the nonwoven fabric, it is difficult to retain it in the nonwoven fabric at a high content rate.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the loss of a water-absorbing agent and the like, to facilitate handling, to promote moisture absorption of contents such as fresh seafood and meat without unevenness, and to have a high drying rate. There is a low price to provide the performance sheet.

[0007]

Means for Solving the Problems The present inventors have studied surface materials that promote water absorption of contents such as fresh seafood and meat by mainly using water-absorbent fibers that absorb salt water well. Completed the invention.

The food packaging sheet of the present invention comprises a first layer of paper located on the side facing the contents and a second layer of non-woven fabric laminated on the outside thereof, the first layer being A wet strength of at least 0.10 kg / 15 mm, preferably at least 0.13 kg / 15 mm, more preferably at least 0.18 kg / 15 mm and at least 10 mm / min, preferably at least 20 mm / min, more preferably at least 40 mm / min. Water absorption rate, wherein the second layer has a water absorption of at least 500 g / m ² , preferably at least 1000 g / m ² .

The second layer is preferably selected from the group consisting of natural fibrous fibers such as cotton, hemp and pulp, regenerated fibrous fibers such as rayon and acetate, and hydrophilic synthetic fibers such as PVA fibers. A non-woven fabric containing at least one hydrophilic fiber as a matrix fiber,
It comprises at least 30% by weight of water-absorbent fibers and / or fine particles having a water absorption of 00% by weight, based on the weight of the nonwoven fabric.

The non-woven fabric of the second layer is preferably 5 to 2
It contains 0% by weight of heat fusible fibers or / and fines in a substantially uniform distribution. Such heat-sealing fibers or fine particles,
It is preferable that at least the surface thereof has an adhesion development temperature which is at least 30 ° C. lower than the melting temperature or the decomposition temperature of other non-woven fabric constituent fibers.

In another preferred embodiment, a third layer made of a water impermeable material is further laminated on the outside of the second layer.

More preferably, the food packaging sheet of the present invention has a softness of at most 200 g, especially at most 130 g, most preferably at most 100 g.

[0013]

The operation of the present invention will be described below together with its operation.
The "wet strength", which defines the characteristics of the food packaging sheet of the present invention, "water absorption rate", "water absorption" and "rigidity" were measured by the following methods, but in all measurements, instead of distilled water Physiological saline was used. Fresh foods to which the sheet of the present invention is applied, especially cell liquids such as seafood and meat show properties close to physiological saline, and the wet characteristics and water absorption of the fiber or its structure are similar to those of distilled water. This is because it is usually different from the case of saline.

Wet strength: Measured according to JIS P 8135-wet tensile strength test method for paper and paperboard. That is,
A test piece with a width of 15 mm and a length of 250 mm is immersed in physiological saline at 20 ± 2 ° C, and then placed on three blotter papers placed on top of it, cover with one blotter paper from the top, and press gently. Except for excess water, the tensile strength was quickly measured by a constant-speed tension type tensile tester or a constant-speed extension type tensile tester before the change in water content of the test piece occurred, and the load indicated value when the test piece ruptured ( kg) is read and the average value of 10 times is wet strength (k
g / 15 mm).

Water absorption rate: Measured in accordance with JIS P 8141-Paper Klemm method water absorption test method. That is,
Test pieces with a width of 15 mm and a length of 250 mm at a temperature of 20 ± 2
Conditioned under standard conditions of ℃ and humidity of 65 ± 2%, kept vertically, up to 5 cm in length, temperature 15
Immediately put in physiological saline at -20 ℃, and set the height from the surface of the saline to the center of the width of the paper in 1 minute.
Read in units, and take the average value of the five measurements as the water absorption rate (m
m / min).

Water absorption: A test piece of about 50 × 50 mm was conditioned and weighed under standard conditions of a temperature of 20 ± 2 ° C. and a humidity of 65 ± 2%, and after being sufficiently impregnated with physiological saline, 454 g of the test piece was placed on the test piece. Drain with the load applied and weigh to obtain the difference from the initial mass. The value is converted into g per 1 m ^{2, and} the average value of the 5 measurements is taken as the water absorption (g /
m ² ).

Bending resistance: JIS L 1096-6.19.5
The measurement was performed according to the E method (handle odometer method).

The food packaging sheet of the present invention has a multi-layer structure. The first layer located on the side facing the contents, that is, the inner side is made of paper, and the water-absorbent layer made of non-woven fabric is provided outside the first layer. It is essential that the layers are laminated, and a water-impermeable protective layer such as a film may be laminated on the outer side of the layers.

The paper forming the first layer is at least 0.10.
Those having a wet strength of kg / 15 mm are preferred. If the wet strength is less than 0.10 kg / 15 mm, it is not suitable because it easily breaks when used in packaging. Further, as the water content of the contents such as fresh seafood and meat increases, the water absorption of the packaging sheet increases, and the packaging sheet easily breaks during transportation of the packaged food, handling, or peeling from the food. , Preferably at least 0.13 kg / 15 m
m, more preferably at least 0.18 kg / 15 mm
It is desirable to select one having a high wet strength depending on the contents.

The water absorption rate of the first layer paper is preferably at least 10 mm / min. If it is less than 10 mm / min, the water absorption from the fresh food will be too late, and the removal of water such as dew condensation or water exuding from the inside of the food will be delayed, which may impair the freshness retention and the taste such as the texture. In addition, when the shape of the contents such as fresh seafood and meat has irregularities, even if water is absorbed at the contacting portion, diffusion may not occur quickly in the first layer, and dry spots may occur. As the water absorption rate increases, the diffusion rate also increases, and the dry spots become smaller. The preferred value of water absorption rate is at least 20 mm / min, more preferably at least 40 mm / min.

As the second water absorbing layer, a non-woven fabric having a water absorption of at least 500 g / m ² is applied. If the water absorption is less than 500 g / m ² , the size, especially the thickness, of the contents such as fresh seafood or meat to be packaged is significantly limited. More preferable value of water absorption is at least 1000 g
/ M ² , and the larger the water absorption amount, the more bulky the fresh food product having a large water content can be used.

The water absorption of the non-woven fabric as the water absorption layer largely depends on the constituent materials. It also depends on the basis weight of the non-woven fabric. Increasing the basis weight is the easiest way to increase the water absorption, but as the layer thickness increases by increasing the basis weight, the sheet's bending resistance, that is, hardness, also increases, causing unevenness in the contents. It is not preferable because it will not accompany.

As the second layer, at least about 15% by weight
At least hydrophilic materials such as cotton, hemp, pulp and the like, regenerated fiber fibers such as rayon and acetate, and synthetic fibers composed of a hydrophilic polymer such as PVA. A non-woven fabric using one kind of hydrophilic fiber as a matrix fiber is preferable. When it is not enough, it is more preferable to use, as the matrix fiber, a fiber made of a water-absorbing polymer capable of absorbing at least about 500% by weight of its own weight of water.
Alternatively, it is preferable to use a non-woven fabric obtained by mixing and molding a water-absorbing material such as a fiber or fine particles made of such a water-absorbing polymer into the hydrophilic matrix fiber.

The water absorbent fiber is more preferably a fiber capable of absorbing at least 1000% by weight of its own weight of physiological saline. Further, it is preferable that at least 30% by weight of the water-absorbent fiber in the second layer is contained.

An example of the water-absorbent fiber is "Lanseal".
(Trade name: manufactured by Toyobo). The water-absorbent fiber is a composite fiber having a sheath component made of a water-absorbent polymer and an acrylic fiber as a core component, and has a fiber strength large enough to withstand carding. However, since the core component is an acrylic fiber, there is a drawback in that the water absorption, in particular, the water absorption of a saline solution such as physiological saline is slightly inferior.

On the other hand, the water absorbent fiber "Oasis" (trade name:
(Manufactured by UK Technical Absorbent Company) exhibits excellent water absorption performance and has a water absorption property of absorbing at least 1000% by weight of physiological saline, which is its own weight, and therefore can be most preferably applied to the present invention.

As the water-absorbing polymer, for example, acrylic acid polymer of starch, polyacrylic acid sodium salt cross-linked product, polyethylene oxide cross-linked product, for example, JP-A-6-61
Examples thereof include water-insoluble polyethylene oxide modified products described in JP-A 1-266661. Examples of commercially available water-absorbing polymers include "KI-Gel 201.
K "(manufactured by Kuraray)," Viscomate PX-112 "(manufactured by Showa Denko)," Aronzap RS-2 "(manufactured by Toagosei Kagaku)," ARASORP S-100 "(manufactured by Arakawa Chemical Industry),
"Aquamate AQ-100" (manufactured by Sekisui Plastics),
There is "Sumikagel S-50" (manufactured by Sumitomo Chemical Co., Ltd.) (both are trade names). Various fine particles of water-absorbent polymer are available, but those of about 50 to 100 μm are available.
In addition to being easily uniformly dispersed, it is advantageous in terms of cost.

The second layer of the non-woven fabric of the sheet of the present invention may be produced, for example, by using the above-mentioned water-absorbent fibers alone or by blending at least 30 wt. A web may be prepared from the aggregate by carding, cross laying or the like, and fine particles of a water-absorbent polymer may be further sprayed if necessary.

When carrying out the above-mentioned carding, it is preferable that the monofilament has a large thickness in case of small fiber strength such as "Oasis", and the monofilament of other fibers to be mixed is preferably thin. . A web can be formed by the thin fibers sinking under the needle of the card and wrapping around the thick fiber above the needle. By selecting the thickness of the single fibers of the fibers to be mixed in this way, it is possible to reduce the loss of the fibers when forming the web. The water-absorbent fiber having a low fiber strength preferably has a thickness of 6 to 15 denier, and the fiber having a high fiber strength preferably has a thickness of 2 to 5 denier. Further, when the fiber length is 50 to 75 mm, the fiber damage is small, which is preferable. In the same sense, contrary to the usual case, it is preferable to shorten the fiber length of the fiber having a large denier and a small fiber strength. The web is not required to be very uniform, and since the fiber denier is relatively large, the roller card is preferable to the flat card, and the single-cylinder woolen type roller card can be advantageously applied.

Thermal bonding and needling are preferably applied as the method of bonding the web thus formed. Thermal bonding is performed by heating appropriately to at least one adhesion developing temperature of the constituent material of the web, for example, a softening temperature or a melting temperature, and fusing or sticking the contact points of the constituent materials to form stability. It is a method of applying or adhering with an impregnated adhesive. Also, needling is commonly used as a method of punching a web with a barbed needle and binding them by entanglement of constituent fibers.

For effective thermal bonding,
The heat-fusible fibers may be mixed or a heat-fusible powder such as polyethylene powder may be sprinkled. At least the surface of the heat-fusible fiber or fine granule is preferably at least 30 higher than the melting temperature or decomposition temperature of other non-woven fabric constituent fibers.
It has a low adhesion development temperature. Examples of commercially available heat-sealing fibers include a composite fiber “ES” (trade name: manufactured by Chisso) having polypropylene as a core component and polyethylene as a sheath component, polyester as a core component and polyethylene or modified polyester as a sheath component. Composite fiber "Bell Combi"
(Trade name: Kanebo). For thermal bonding, 5 to 20% by weight of these heat fusion fibers and / or heat fusion powders are mixed. If it is less than 5% by weight, it is necessary to use needle punching together in order to ensure strong bonding.

Thermal bonding is used to disperse and fix the water-absorbent polymer fine particles in the nonwoven fabric to prevent the fine particles from falling off.
That is, the web in which the water-absorbent polymer fine particles have been previously sprayed may be subjected to an appropriate heat treatment so that the polymer fine particles and the fibers may be fused or glued, or may be fixed by the action of the impregnated adhesive. . After needling, spray water-absorbent polymer fine particles, and then needling lightly and heat treatment,
It can be dispersed and fixed relatively uniformly.

Further, as another method for manufacturing the above-mentioned second layer non-woven fabric, the air lay method can be applied. In this case, it is preferable that the thickness of the water-absorbent fiber having a low fiber strength is 6 to 15 denier because it is easily dispersed. The fiber length of the water absorbent fiber is preferably 4 to 15 mm in the same sense. The matrix fibers applied to this method preferably have properties similar to the water-absorbent fibers.

Also in this case, in the case of thermal bonding, 5 pieces of heat-sealing fiber or / and heat-sealing powder are used.
It may be mixed in an amount of up to 20% by weight. If the amount is less than 5% by weight, the bonding will be insufficient, so that it becomes necessary to support it with another non-woven fabric or paper for easy handling.

The non-woven fabric of the second layer may be mixed with antibacterial and deodorant fibers or particles such as activated carbon fine particles and zeolite. Further, the first layer of paper may be the one that has been subjected to the same processing, or the one that has been subjected to processing such as coloring and embossing.

In the food packaging sheet of the present invention, in addition to the above-mentioned two layers, a water-impermeable third layer may be further laminated on the outside thereof. By doing so, even if a remarkably large amount of water is locally concentrated, it does not leak out, which is preferable depending on the type of food.

The bending resistance of the food packaging sheet of the present invention is preferably at most 200 g, more preferably at most 1.
30 g, most preferably at most 100 g. By suppressing the bending resistance to be small and making it flexible, for contents with uneven thickness unevenness, or for contents in which a plurality of individual small foods are arranged on the packaging material and the space between them is depressed However, you can follow the uneven shape well,
Water can be absorbed uniformly from food.

[0038]

EXAMPLES The present invention will be described in more detail with reference to examples. Example 1 Basis weight of 18 g / as a first layer on a conveyor type suction net
m²Heat sealable paper, type DM802 (Miki
(Made of special paper). Water absorption rate of this paper is 50mm
/ Min, wet strength was 0.2 kg / 15 mm. That
On top, 30% by weight of water-absorbent fiber "Oasis" 9d x 6m
m, 60% by weight crushed pulp and 10% by weight heat fusion fiber
Wei "Bell Combi" type 6080, open 2d x 6mm
While the second layer is uniformly and continuously formed by the air lay method.
Sprinkle with a basis weight of 118 g / m²Were laminated so that
The adjustment of the basis weight is based on Net Speed and "Oasis" and other items.
The application amount of two layers was measured continuously. Then this
30 g / m 2 basis weight on the second layer ²Polyethylene film
(Third layer) is laminated to form a three-layer structure, and the food packaging of the present invention
The sheet was manufactured. The water absorption of this packaging sheet is 1500
g / m²The bending resistance was 98 g.

3 pieces of horse mackerel are placed between the packaging sheets,
When 0 to 150 g / piece of fillet was sandwiched and sealed in a polyethylene bag and kept in a refrigerator at 4 ° C, the weight loss of the contents after 8 hours was 12% by weight, and the weight loss after 24 hours was It was 23% by weight. When the packaging sheet was removed from the fillet after 24 hours, the first layer of paper was not damaged.

When this mackerel fillet after being kept cold for 8 hours was compared with a naturally dried overnight dried product, the fillet using the product of the present invention was aging and was soft, and the taste was evaluated by a blind test by 10 panelists. As a result of comparison, 24% was more preferred than natural drying.

Example 2 In the same manner as in Example 1 except that the wet strength of the paper of the first layer was changed as shown in Table 1, the polyethylene bag was removed during the cold preservation, and the severe condition was applied. With respect to the conditions of insertion, 10 sheets of the paper were observed for breakage after 24 hours, and the results are shown in Table 1.

[0042]

[Table 1]

Example 3 The weight loss of the contents after 12 hours was measured in the same manner as in Example 1 except that the water absorption rate of the first layer paper was changed as shown in Table 2 and the results are shown in Table 2. It was shown to. The water absorption rate of the paper was changed depending on the amount and kind of the additive such as sulfuric acid band added at the time of paper making.

[0044]

[Table 2]

Example 4 The weight loss of the contents after 12 hours was carried out in the same manner as in Example 1 except that the water absorption of the second water absorbing layer was changed as shown in Table 3 by changing the basis weight of the sheet. Was measured and the results are shown in Table 3.

[0046]

[Table 3]

Example 5 The packaging sheet produced in Example 1 was changed in the temperature of the pressure hot roller from 130 ° C. to 170 ° C., and the pressure was changed. A wrapping sheet was produced, and a fillet with a skeleton of the eel was wrapped in the same manner as in Example 1, and the wrapping ease was compared. The results are shown in Table 4.

[0048]

[Table 4]

[0049]

EFFECTS OF THE INVENTION The food packaging sheet of the present invention has less loss of water-absorbing agents and the like, is easy to handle, and promotes even absorption of moisture in contents such as irregularly-shaped fresh seafood and meat without unevenness. High drying speed.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Megumi Shibuya 1-3-7 Main Office, Sumida-ku, Tokyo

Claims (14)

[Claims] 1. A first layer made of paper and a second layer made of non-woven fabric laminated on the outer side of the first layer, the first layer being on the side facing the contents, and the first layer being at least 0.10 kg /
A food packaging sheet, which exhibits a wet strength of 15 mm and a water absorption rate of at least 10 mm / min, and wherein the second layer has a water absorption of at least 500 g / m ² . 2. The wet strength of the first layer is at least 0.13.
The food packaging sheet according to claim 1, which is kg / 15 mm. 3. Wet strength of at least 0.18 kg / 1
The food packaging sheet according to claim 2, which is 5 mm. 4. The water absorption rate of the first layer is at least 20 mm.
/ Min. The food packaging sheet according to any one of claims 1 to 3. 5. The food packaging sheet according to claim 4, wherein the water absorption rate is at least 40 mm / min. 6. The non-woven fabric in which the second layer is a matrix fiber containing at least one hydrophilic fiber selected from the group consisting of natural fibrous fibers, recycled fibrous fibers and hydrophilic synthetic fibers. 5. The food packaging sheet according to any one of 5 to 5. 7. The food packaging sheet according to claim 6, wherein the second layer contains at least 30% by weight of water-absorbent fibers or / and fine particles having a water absorption of at least 1000% by weight, based on the weight of the nonwoven fabric. 8. The water absorption of the second layer is at least 1000 g.
/ M ² The food packaging sheet according to claim 7. 9. The food product according to claim 1, wherein the nonwoven fabric of the second layer contains 5 to 20% by weight of the heat-sealing fibers or / and fine particles in a substantially uniform distribution. Packaging sheet. 10. The food packaging sheet according to claim 9, wherein the heat-fusible fibers or / and fine particles have an adhesion development temperature at least 30 ° C. lower than the melting temperature or decomposition temperature of other non-woven fabric constituent fibers, at least on the surface thereof. 11. The food packaging sheet according to claim 1, wherein a third layer made of a water impermeable material is further laminated on the outside of the second layer. 12. The food packaging sheet according to claim 1, having a bending resistance of at most 200 g. 13. The bending resistance is at most 130 g.
Food packaging sheet. 14. The bending resistance is at most 100 g.
Food packaging sheet.