JP2011162246A - Drip absorbing sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a sheet showing a little increase of a volume when fresh fish or the like is wrapped with the sheet, moderately absorbing a drip generated after freezing and thawing the fresh fish or the like but does not cause a decrease of taste due to too much absorption of the drips even after freezing the same for a long period of time, in such a form that the sheet can be cut with a pair of scissors for use. <P>SOLUTION: The drip absorbing sheet is formed of a non-woven fabric which contains a pulp fiber having an average fiber length of less than 20 mm, a hydrophobic thermoplastic resin fiber having an average fiber length of not less than 30 mm and a hydrophilic fiber having an average fiber length of not less than 20 mm, and has a thickness of not more than 0.5 mm wherein the amount of desorbed water returned is 10 to 100 g/m<SP>2</SP>. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an absorbent sheet for wrapping fresh fish, meat and the like and storing them frozen.

  The recent trend toward savings, safety and domestic food has led to a growing tendency to make good use of food preservation in the home. When the purchased food cannot be used up, these foods can be stored frozen and eaten. Opportunities to be unzipped before use are increasing.

  Thawing methods include (1) thawing in a refrigerator room at around 5 ° C., (2) thawing at room temperature, (3) thawing with running water, (4) thawing in a microwave oven, etc. is there. When these are thawed, a liquid called drip flows out from fresh fish, meat, etc., although there are some amounts depending on the method. This drip is one of the top causes of stress in handling fish because it causes kitchen fouling and raw odor while preparing fresh fish. Fresh fish and the like contain about 70 to 80% of water, and these waters are divided into bound water that is strongly bound to the protein constituting the fresh fish and free water that is weakly bound to the protein. Free water freezes and expands at the freezer temperature (about −20 ° C.) of a household refrigerator, destroys the cell membrane, and flows out with water-soluble components in the cells upon thawing. This effluent is a drip. In addition, when frozen fish is frozen and stored for a long period of time, the amount of free water increases due to the change in pH inside the food, and the amount of free water increases. There was also a problem that the ingredients felt watery.

  Proposals have been made for a sheet that absorbs a drip flowing out from fresh fish or the like. Patent Documents 1 and 2 disclose a drip-absorbing sheet composed of a thermoplastic fiber nonwoven fabric and a pulp fiber bonded together. Has proposed a liquid-absorbent sheet for foods comprising an absorbent paper containing a highly water-absorbing polymer for the absorbent layer and sandwiched between a water-permeable surface material and a water-impermeable back material.

Japanese Utility Model Publication No. 61-74429 Japanese Utility Model Publication No. 2-29722 Japanese Patent Laid-Open No. 10-296079

  However, since the drip absorbent sheet having the structure described in Patent Document 1 or Patent Document 2 has no entanglement between the hydrophobic fiber and the pulp fiber, the amount of water retained between the fibers is not large. Therefore, if the thickness of the sheet is 0.5 mm or less, a large amount of drip that comes out when thawing freshly frozen fish or the like cannot be absorbed. And when the load of fresh fish etc. is added to a sheet | seat, since the absorbed drip will return to the fish surface, it has the subject that fresh fish etc. become a raw smell or watery. On the other hand, increasing the drip absorption by making the sheet thickness thicker than 0.5 mm causes a new problem of increasing the volume increase rate when occupying fresh fish or the like and occupying the freezer compartment volume. .

  Moreover, in the sheet | seat of patent document 3, since the drip absorption amount is high and even if it absorbs the drip which comes out at the time of thawing | decompression, it is difficult for a drip to return to the fish surface by the load of fresh fish etc. However, when fresh fish or the like is stored for a long time, there is a problem that moisture of the fresh fish or the like is absorbed excessively, resulting in a crunchy texture or cracking on the surface of the food material. In addition, since the absorbent sheet is bulky, the volume increase when wrapping fresh fish etc. becomes large, and the problem of occupying the volume of the freezer, and if the absorbent sheet is cut according to the size of fresh fish etc., the high water absorption There was a usability problem that the polymer migrated to the surface of meat fish.

  For this reason, it is possible to adjust the size of the freezer according to the size of the packaged goods, which absorbs drip generated during freezing and thawing of fresh fish, meat, etc. A drip-absorbing sheet with a small volume increase that can effectively use the internal volume has not yet been invented.

  In view of the above problems, the present invention appropriately absorbs the drip produced during freezing and thawing of fresh fish, meat, etc., so that the fresh fish becomes odorous or watery, or has a crispy texture or food surface. Providing a drip-absorbing sheet that is easy to use because it suppresses the occurrence of cracks and can be arbitrarily changed in size according to the size of the item to be packaged and can effectively use the freezer's internal volume. With the goal.

As a result of intensive studies to solve the above problems, the present inventor is a non-woven sheet having a thickness of 0.5 mm or less, and the sheet is composed of pulp fiber, hydrophobic thermoplastic resin fiber and hydrophilic fiber, and absorbs water. When the return amount is 100 g / m ² or less, it has been found that high drip absorption performance and excellent usability are exhibited, and the present invention has been completed.

The drip absorbent sheet of the present invention is
(1) Pulp fibers having an average fiber length of less than 20 mm, hydrophobic thermoplastic resin fibers having an average fiber length of 30 mm or more, and hydrophilic fibers having an average fiber length of 20 mm or more, and a thickness of 0.5 mm or less A drip absorbent sheet comprising a nonwoven sheet and having a water absorption return amount of 100 g / m ² or less.
Also,
(2) In the drip absorbent sheet according to (1), the nonwoven fabric sheet contains 50 to 45% by weight of pulp fibers having an average fiber length of less than 20 mm, and 50 hydrophobic thermoplastic resin fibers having an average fiber length of 30 mm or more. It is good also as including 5 to 10weight% of hydrophilic fibers with -55weight% and an average fiber length of 20 mm or more.
Also,
(3) In the drip absorbent sheet according to (1) or (2), the hydrophobic thermoplastic resin fiber having an average fiber length of 30 mm or more is a polyethylene terephthalate fiber, and the hydrophilic fiber having an average fiber length of 20 mm or more is It may be rayon fiber.

  The absorbent sheet of the present invention appropriately absorbs drip and free water generated during cold thawing of fresh fish, etc., and the raw odor and wateriness of the thawed fresh fish, etc. Can be suppressed. Moreover, since the rate of system increase when wrapping fresh fish or the like is small, the volume in the freezer can be used effectively. Furthermore, since the amount of powder leakage at the time of cutting is small, the absorbent sheet can be appropriately cut and used according to the size of the fresh fish to be used, so that excellent usability can be exhibited.

  According to the present invention, by appropriately absorbing the drip produced during freezing and thawing of fresh fish, meat, etc., it is possible to suppress the fresh fish from becoming odorous or watery, or causing a crispy texture or cracking of the food surface. In addition, it is possible to provide a drip absorbent sheet that is easy to use because the size of the absorbent sheet can be arbitrarily changed in accordance with the size of the packaged item and the inside volume of the freezer can be used effectively.

  As mentioned above, in order to store fresh foods such as fresh fish in a frozen state and eliminate the odor and wateriness that occurs when thawing, they efficiently absorb the drip generated from fresh fish and the free water in the fresh foods. It is necessary to let This is because it is generally said that the cause of the fishy odor is water-soluble trimethylamine or dimethylamine produced in the fish during the storage period, and the drip itself in which the compound is dissolved generates a odorous smell. It is. In addition, since the amount of free water remaining in the fish after freezing and thawing affects the wateriness of the fish, reducing the drip remaining on the surface of the fish suppresses the fish's raw odor and reduces the amount of free water in the fish. Will lead to the elimination of the wateriness of the fish.

  The drip absorbent sheet according to the present invention includes a pulp fiber having an average fiber length of less than 20 mm, a hydrophobic thermoplastic resin fiber having an average fiber length of 30 mm or more, and a hydrophilic fiber having an average fiber length of 20 mm or more. . Preferable composition ratios are 40 to 45% by weight of pulp fibers, 50 to 55% by weight of hydrophobic thermoplastic resin fibers, and 5 to 10% by weight of long-fiber hydrophilic fibers.

When the pulp fiber is 40% by weight or more, the sheet thickness is 0.5 mm or less and drip and free water can be sufficiently absorbed. When the hydrophobic thermoplastic resin fiber is 50% by weight or more, it is easy to achieve a water absorption return of 100 g / m ² or less, and the drip does not remain on the fish surface, and it is difficult to cause problems such as freshness and raw odor. When the hydrophilic fiber of the long fiber is in the range of 5 to 10% by weight, the water adhering to the sheet surface is easily induced inside the sheet, so it absorbs free water in fresh fish etc. in a short time until freezing. Is possible. Thereby, it becomes possible to further suppress cell destruction due to moisture freezing, and as a result, it is possible to further suppress the amount of drip generated.

  As a preferable structure, a non-woven sheet is formed so that both fibers are entangled after superposing a hydrophobic thermoplastic fiber on the surface and a highly absorbable pulp fiber on the inner surface, and the hydrophobic thermoplastic resin fiber on the surface Is a structure in which many pulp fibers are distributed in the center. By adjusting the distribution of the hydrophobic thermoplastic resin fibers on the surface and the spaces between the fibers, it is possible to easily achieve the above-described water absorption return amount and contact angle change amount. Furthermore, the above-mentioned water absorption can be easily achieved by the distribution of the central pulp fiber and the space between the fibers. Further, when the hydrophilic fibers of the long fibers are entangled with both the thermoplastic resin fibers distributed on the surface and the pulp fibers distributed on the center, the drip attached to the surface is easily guided to the center. Therefore, it is easy to achieve the contact angle variation described above, and water can be absorbed quickly into the pulp fibers distributed in the center. This makes it possible to absorb free water in fresh fish, etc. in a short amount of time until freezing when storing fresh fish, etc. in a freezer, and thus it is possible to further suppress cell destruction due to moisture freezing, As a result, the amount of drip generated can be further suppressed.

  For this purpose, the average fiber length of the hydrophilic fibers is preferably 20 mm or more because drip induction is facilitated, and more preferably 30 mm or more.

  The average fiber length of the pulp fibers is preferably less than 20 mm. If it is less than 20 mm, the space between the pulp fibers is increased, and a large amount of drip can be taken into the space.

  It is preferable that the average fiber length of the hydrophobic thermoplastic resin fiber is 30 mm or more, since it is easily entangled with the pulp fiber, so that the drip taken into the fiber space can be easily held. Moreover, since the amount of powder leakage generated at the time of sheet cutting can be suppressed, it is preferable.

As for the absorption sheet of this invention, it is desirable that the amount of powder leakage from the sheet | seat cut out to the magnitude | size of 10 cm x 10 cm is 10 mg / 100cm < ² > or less. It is preferable for the amount of powder leakage to be 10 mg / 100 cm ² or less because a method of cutting a sheet and wrapping meat fish can be employed from the viewpoint of food hygiene.

  As a preferable pulp fiber, known softwood pulp or hardwood pulp can be used, and softwood pulp fiber is particularly preferable.

  Preferable hydrophobic thermoplastic resin fibers include polyethylene fibers, polypropylene fibers, polyester fibers, nylon fibers, acrylic fibers, and the like, and polyethylene terephthalate fibers are particularly preferable.

  Examples of preferable long-fiber hydrophilic fibers include rayon fibers. Moreover, the hydrophilic fiber which provided hydrophilicity by apply | coating surfactant etc. to the hydrophobic fiber surface whose average fiber length is 20 mm or more is also mentioned as a preferable example. Examples of hydrophobic fibers used at this time include polyethylene fibers, polypropylene fibers, polyester fibers, nylon fibers, acrylic fibers, and the like. Examples of surfactants include nonionic polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, glycerin fatty acid esters, sorbitan fatty acid esters, and anionic ones. Alkyl sulfonates, alkyl benzene sulfonates, alkyl sulfates, alkyl phosphates, and the like. Also, cationic quaternary ammonium chloride, quaternary ammonium sulfate, and quaternary ammonium nitrate, and amphoteric alkylbetaine type, alkylimidazoline type, alkylalanine type and the like can be mentioned.

It is important that the drip absorbent sheet of the present invention is a nonwoven fabric sheet having a thickness of 0.5 mm or less and a water absorption return amount of 10 g / m ² or more and 100 g / m ² or less. When fresh fish or the like is wrapped with an absorbent sheet having a thickness of 0.5 mm or less, an increase in the volume of the packaged fresh fish or the like is suppressed, and there is an effect that a home freezer can be used effectively. If the thickness exceeds 0.5 mm, the absorbent sheet is bulky, which causes a problem of an increase in volume when wrapping fresh fish or the like.

The amount of water absorption returned is 2 g of purified water evenly absorbed on a sheet piece cut into a 10 cm square, and a filter paper (corresponding to three types of JIS P 3801) that has been weighed in advance is immediately placed on the sheet. This is a value obtained by measuring the weight increase of the filter paper after applying a weight of 1 kg and a cross-sectional area of 100 cm ² for 10 seconds.

When the water absorption return amount is 100 g / m ² or less, the absorbed drip does not return to the surface of fresh fish or the like again, so that the following two effects can be expressed. One is to reduce the amount of drip remaining on the surface of fresh fish and so on, and the other is to reduce the free water remaining on fresh fish, etc., and to reduce the wateriness of fresh fish after cold thawing. It is to eliminate. The mechanism for eliminating wateriness is to reduce the water concentration at the interface between the surface of the fresh fish and the absorbent sheet and form a concentration gradient between the surface of the fresh fish and the internal water. It is thought that diffusion to the surface is promoted.

When the water absorption return amount exceeds 100 g / m ² , a high-concentration drip layer is formed on the surface of fresh fish and the like, and thus the problem that the fresh fish after thawing becomes watery and the problem of raw odor arise. When the water absorption return amount is 50 g / m ² or less, the water concentration gradient between the fresh fish and the absorbent sheet is large, so that the free water inside the fish is reduced even if the fish has a large amount of free water or has a large thickness. This is preferable.

A smaller water absorption return amount is preferable in terms of reducing the drip layer formed on the surface of fresh fish or the like, but if the water absorption return amount is less than 10 g / m ² , it may be difficult to quickly take the drip inside the absorbent sheet. Arise. The reason for this is not clear, but it is thought that the surface is too hydrophobic and water repellent.

The water absorption of the absorbent sheet of the present invention is preferably 200 g / m ² or more and 1000 g / m ² or less. When the water absorption is 200 g / m ² or more, it is easy to sufficiently absorb drip and free water from fresh fish, etc., and it becomes easy to achieve the above-mentioned water absorption return of 100 g / m ² or less, so that the drip remains on the fish surface. Therefore, it is difficult to cause problems such as freshness and odor. When the amount of water absorption is 1000 g / m ² or less, when fresh fish is stored for a long time, it does not absorb too much water such as fresh fish, and the texture and the surface of ingredients are not easily cracked, improving the texture and taste. To do. More preferably, the absorption amount is 300 g / m ² or more and 800 g / m ² or less, and the water absorption return amount is 80 g / m ² or less. In this case, excess drip generated after freezing and thawing in many fresh fish and the like can be absorbed and optimally maintained without taking too much water in the fresh fish and the like.

The basis weight of the absorbent sheet of the present invention is preferably 30 g / m ² or more and 60 g / m ² or less. Since the water absorption amount of the absorbent sheet is the sum of the absorption amount of hydrophilic fibers including pulp fibers and the water retention amount retained in the fiber space, the distribution and blending ratio of the hydrophilic fibers and the size of the fiber space are important. In order to make this fiber space suitable, a thickness of 0.5 mm or less and a basis weight of 30 g / m ² or more and 60 g / m ² or less are preferable. If it is this range, the absorption amount of a hydrophilic fiber is moderate, and sufficient drip absorption amount can be exhibited.

  In the present invention, the amount of change in the contact angle between 2 milliliters of purified water measured in accordance with JIS-R-3257 and the absorbent sheet surface is preferably -5 degrees / millisecond or less (however, the contact angle The amount of change refers to the amount of change in contact angle from 2 milliseconds to 10 milliseconds after landing on the water-absorbing sheet (the same applies hereinafter). Absorbing free water in fresh fish, etc. in a short time until freezing when storing fresh fish in a freezer by using a non-woven sheet with a contact angle change of -5 degrees / millisecond or less As a result, it becomes possible to further suppress cell destruction due to moisture freezing, and as a result, the amount of drip generated can be further suppressed, so that the raw odor and wateriness of the fish after thawing can be further suppressed. Can do. A more preferable change amount of the contact angle is -12 degrees / millisecond or more and -6 degrees / millisecond or less.

  Further, in addition to the contact change amount described above, it is more preferable that the contact angle between the purified water and the absorbent sheet 2 milliseconds after the purified water comes into contact with the water absorbent sheet is 120 degrees or more and 180 degrees or less. This contact angle means that the surface of the sheet is highly hydrophobic, and the absorbed drip is less likely to return to the surface of the fish. Therefore, when fresh fish freezes, it absorbs free water in the fresh fish in a shorter time. This is because it becomes possible.

  The absorbent sheet of the present invention has a volume increase rate of 1.3 times or less when a rectangular parallelepiped dummy sample (length 125 mm × width 65 mm × height 25 mm) simulating the shape of a typical meat fish stored at home is wrapped. It is preferable that When the volume increase rate is small, the volume increase after wrapping fresh fish is small, so that the free space in the freezer can be stored effectively.

  A known manufacturing method can be used as a manufacturing method of the absorbent sheet having such a configuration. For example, a spunbond method, a carding method, an airlaid method, a spunlace method, a needle punch method, a melt blow method, or the like can be employed. Among these production methods, a spunlace method in which an adhesive is not used as a nonwoven fabric used for food applications is preferable. The production method of the spunlace method includes: a sheet formed by collecting rayon fibers; a paper sheet obtained by wet papermaking of wood pulp fibers; and a melt blown sheet obtained by forming a thermoplastic resin into fine fibers using high-temperature high-speed gas. As an example, the sheet is laminated in a combination in which the thermoplastic resin fibers are the outermost layer, and a high-pressure water flow is applied from the thermoplastic resin fiber side to entangle each fiber in a three-dimensional manner. Can be mentioned.

  The absorbent sheet of the present invention may be embossed, but when it is not embossed, the adhesion between the meat fish and the absorbent sheet increases when wrapping meat fish with the absorbent sheet, and as a result, it is stored in the freezer. It is preferable because free water can be efficiently absorbed in a short time until the water in the fresh fish freezes.

  As described above, the absorbent sheet of the present invention can appropriately absorb the drip in the frozen and thawed storage, thereby reducing the wateriness of fresh fish and the like and suppressing the occurrence of raw odor. In addition, even when stored frozen for a long period of time, it does not absorb the moisture of meat fish too much, resulting in a crispy texture or cracking on the surface of the food material, and should be suitably used for freezing and thawing storage of fresh fish etc. it can.

  Embodiments of the present invention will be described below with examples.

The sheets described in Examples and Comparative Examples were evaluated by the following test methods. The obtained results are shown in Table 1.

<Test method>
1. Absorption sheet thickness Using a constant pressure thickness measuring instrument (Ozaki Mfg. Co., Ltd .: FFG12), the thickness is measured with a load of 0.4 N or less.
2. Basis weight It cuts out from an absorption sheet to 10 cm x 10 cm, measures the weight W1, and calculates from the following formulas.
Basis weight (g / m ² ) = W1 × 100
3. Average fiber length of the fibers constituting the sheet After the fibers constituting the sheet are arbitrarily extracted and the type of the fibers configured using IR is specified, the fiber length is determined according to the measurement method of JIS L1030 for 20 arbitrary fibers of the same type. The average value is obtained by measurement to obtain the average fiber length.

4). Contact angle Measured according to the measurement method of JIS R 3257 using DM-501 (HAS-220 model) manufactured by Kyowa Interface Chemical. Among the measurement conditions, 2 μl of purified water was used as the droplet volume, and the contact angle was measured by continuously taking images taken before and after the droplet contacted the sample at intervals of 2 milliseconds. And measure the contact angle between the absorbent sheet surface.
5. Water absorption amount A 10 cm × 10 cm test piece (weight W1) was cut out from the obtained sheet and immersed in purified water for 1 minute, then the test piece was taken out, and the weight (W2) after suspending for 3 minutes while holding one corner. ) To measure the amount of increase (W2-W1) and calculate the amount of water absorption from the following formula.
Water absorption (g / m ² ) = (W2−W1) /0.01
6). Water absorption return amount 10 g square cut test piece equally 2 g of purified water, and immediately put a filter paper (corresponding to three types of JIS P 3801) that weighed in advance, load 1 kg on the sheet The weight increase of the filter paper after applying a weight of 100 cm ² for 10 seconds is measured.

7). Amount of powder leakage A test piece cut out to 10 cm × 10 cm was dropped into a beaker containing 300 ml of purified water, stirred for 1 minute at 600 rpm, and then the remaining residue was taken out of the filter paper (corresponding to three types of JIS P 3801) ). After the residue after filtration is dried at 80 ° C. for 1 hour, the weight W is measured to determine the amount of powder leakage.
8). Volume increase rate A rectangular dummy sample of length 125mm x width 65mm x height 25mm is wrapped with a sheet cut to 200mm x 300mm, and the length L2 (mm), width W2 (mm), and height H2 (mm) are measured from the top of the sheet. Then, the volume increase rate is calculated from the volume (L2 × W2 × H2) after wrapping.
Volume increase rate (times) = (L2 × W2 × H2) / (125 × 65 × 25)

9. Drip Absorbency 100g of tuna fillet is wrapped in a sheet of 300mm x 250mm, put in a bag with zipper, frozen in the freezer of the refrigerator for 14 days, then transferred to the refrigerator and thawed. When tasting tuna after thawing, the following criteria are used to evaluate the raw odor, the wateriness when eating, the crispy feeling when eating, and the presence or absence of cracks.
Raw odor ◎ Feels almost no raw odor ○ Feels only a slight raw odor × Watery feels raw odor ◎ Does not feel wet when eaten without surface ○ Surface is not wet Slightly watery when eaten × The surface is wet and the watery taste is not delicious when eaten ◎ There is a lot of moisture and you can not feel the crispness × Cracking that is not delicious ◎ No cracking × There is cracking

10. Usability Evaluate the ease with which about 100 g of salmon fillet is wrapped in an absorbent sheet, the bulkiness when wrapped with a sheet, and the sheet cutting property according to the following criteria.
Ease of wrapping ◎ Easy to wrap close to the fillet ○ Slightly adherence × Bulkiness difficult to wrap and difficult to wrap ◎ Bulkiness almost the same as salmon fillet
○ Slightly bulkier than salmon fillet × Sheet cutting ability that is considerably bulkier than the size of salmon fillet ◎ Can be used by cutting the sheet

[Example 1]
Polyethylene terephthalate fiber sheet having a basis weight of 25 g / m ² prepared by a melt blow method, a pulp fiber sheet having a basis weight of 20 g / m ² made by wet papermaking from softwood kraft pulp, and a large number of rayon filaments are intertwined with each other. After stacking rayon fiber sheets with a basis weight of 5 g / m ² that were accumulated in this way, they were placed on a conveyor formed of a wire mesh and the laminate was transferred at 20 m / min, and the nozzle hole diameter was 0.15 mm and the nozzle spacing was set at 1 mm The sheet was obtained by performing a high-pressure water column flow treatment with a water pressure of 50 kg / cm ² from the polyethylene terephthalate fiber sheet side using the high-pressure water column flow injection device.

[Example 2]
Polyethylene terephthalate fiber sheet having a basis weight of 40 g / m ² prepared by a melt blow method, a pulp fiber sheet having a basis weight of 20 g / m ² made by wet papermaking from softwood kraft pulp, and a large number of rayon filaments are intertwined with each other. After stacking rayon fiber sheets with a basis weight of 3 g / m ² that were accumulated in this way, they were placed on a conveyor formed of a wire mesh and the laminate was transferred at 20 m / min, and the nozzle hole diameter was 0.15 mm and the nozzle spacing was set at 1 mm The sheet was obtained by performing a high-pressure water column flow treatment with a water pressure of 50 kg / cm ² from the polyethylene terephthalate fiber sheet side using the high-pressure water column flow injection device.

Example 3
Fibers intertwined with polypropylene fiber sheet with basis weight of 40 g / m ² prepared by melt blow method, pulp fiber sheet with basis weight of 20 g / m ² wet-made from softwood kraft pulp, and many rayon long fibers. After stacking the rayon fiber sheets with a grammage of 3 g / m ² accumulated on the substrate, the laminate is placed on a conveyor formed of a wire mesh and transferred at a rate of 3 m / min, and the nozzle hole diameter is 0.15 mm and the nozzle spacing is 1 mm. Using a high pressure water column jetting apparatus, a high pressure water column flow treatment was performed from the polypropylene fiber sheet side at a water pressure of 50 kg / cm ² to obtain a sheet.

[Comparative Example 1]
A pulp fiber sheet having a basis weight of 20 g / m ² prepared by wet papermaking from softwood kraft pulp and a polypropylene fiber sheet having a basis weight of 15 g / m ² prepared by a melt blow method in the order of a polypropylene fiber sheet, a pulp fiber sheet, and a polypropylene fiber sheet. A sheet was obtained by laminating using an ethylene vinyl acetate adhesive.

[Comparative Example 2]
A polypropylene fiber sheet having a basis weight of 40 g / m ² prepared by a melt blow method was used.

[Comparative Example 3]
After laminating a 25 g / m ² basis weight melt blow sheet prepared by a melt blow method using polypropylene resin and a rayon fiber sheet having a basis weight of 35 g / m ² accumulated so that a large number of rayon filaments are intertwined with each other. Using a high-pressure water column jetting device installed on a conveyor formed of a wire mesh and transporting the laminate at 20 m / min and having a nozzle hole diameter of 0.15 mm and a nozzle spacing of 1 mm, the water pressure is 50 kg / cm ² . An integrated sheet was obtained by high-pressure water column treatment.

[Comparative Example 4]
Fibers intertwined with each other in polypropylene fiber sheets with a basis weight of 18 g / m ² prepared by the melt blow method, pulp fiber sheets with a basis weight of 9 g / m ² , made from softwood kraft pulp as a raw material, and a large number of rayon filaments. After stacking rayon fiber sheets with a grammage of 18 g / m ² accumulated on the substrate, they are placed on a conveyor formed of wire mesh and the laminate is transported at 3 m / min, and the nozzle hole diameter is 0.15 mm and the nozzle spacing is 1 mm. Using a high pressure water column jetting apparatus, a high pressure water column flow treatment was performed from the polypropylene fiber sheet side at a water pressure of 50 kg / cm ² to obtain a sheet.

[Comparative Example 5]
A pulp fiber sheet with a basis weight of 11 g / m ² , which is wet-made from softwood kraft pulp, is placed up and down with a rayon fiber sheet with a basis weight of 23 g / m ² that is accumulated so that a large number of rayon fibers are intertwined with each other. After laminating so as to be sandwiched, rayon fibers are placed on a conveyor formed by a wire mesh and the laminated body is transferred at 3 m / min, and a nozzle hole diameter is 0.15 mm and a nozzle interval is set to 1 mm, using a high-pressure water column jet device. A high-pressure water column flow treatment was applied from the side at a water pressure of 50 kg / cm ² to obtain a sheet.

[Comparative Example 6]
Pulp fibers及3.5g and the superabsorbent polymer 3.5g mixture 300 mm × 250 mm in sandwiched by the size of the basis weight of 18 g / ^{m 2} tissue is absorbent surface material basis weight 22 g / ^{m 2} paper And 10 μm-thick polyethylene film as the back material, and the side surface was heat-sealed to obtain an absorbent sheet.

<Consideration of test results>
Examples 1-3, by the water returning amount as 10 to 100 g / ^{m 2,} compared with Comparative Example 1-5 in which the water absorption amount of return is greater than 100 g / ^{m 2,} water-absorbent (especially fishy smell and water The evaluation of (paste) is good. Moreover, Examples 1-3 are easy to use (particularly ease of wrapping and bulk) compared to Comparative Example 2 in which the absorbent sheet thickness exceeds 0.6 mm by making the absorbent sheet thickness 0.5 mm or less. Evaluation is good. Thereby, it turned out that it is preferable to make a water absorption return amount into 10-100 g / m < ² > and to make sheet thickness 0.5 mm or less.

  Among Examples 1 to 3, in particular, Example 1 has a hydrophobic thermoplastic resin fiber content of 50 to 55% by weight, pulp fiber content of 40 to 45% by weight, and hydrophilic fiber content of 5 to 10% by weight. By doing, compared with Example 2, 3, evaluation of a raw odor and wateriness is still better. Thereby, it turned out that it is preferable to make hydrophobic thermoplastic resin fiber 50 to 55 weight%, pulp fiber 40 to 45 weight%, and hydrophilic fiber 5 to 10 weight%.

  Comparative Example 6 is an absorbent sheet using a superabsorbent polymer and a polyethylene film instead of polyethylene terephthalate fiber and rayon fiber. Although the comparative example 6 has good evaluation regarding the raw odor and wateriness, the evaluation of crispness and cracking is poor, and the usability is also poor. Therefore, it was found that a drip absorbent sheet containing polyethylene terephthalate fiber and rayon fiber is preferable.

  The absorbent sheet of the present invention can be suitably used as an absorbent sheet that effectively absorbs drip and free water in the field of storing and thawing fresh fish and fish ingredients.

Claims (3)

Pulp fibers having an average fiber length of less than 20 mm, hydrophobic thermoplastic resin fibers having an average fiber length of 30 mm or more, and a nonwoven fabric sheet having a thickness of 0.5 mm or less including hydrophilic fibers having an average fiber length of 20 mm or more The drip absorbent sheet is characterized in that the water absorption return amount is 10 to 100 g / m ² .   The nonwoven fabric sheet is 40 to 45% by weight of the pulp fiber having an average fiber length of less than 20 mm, 50 to 55% by weight of the hydrophobic thermoplastic resin fiber having an average fiber length of 30 mm or more, and an average fiber length of 20 mm or more. The drip absorbent sheet according to claim 1, comprising 5 to 10% by weight of the hydrophilic fiber.   The hydrophobic thermoplastic resin fiber having an average fiber length of 30 mm or more is a polyethylene terephthalate fiber, and the hydrophilic fiber having an average fiber length of 20 mm or more is a rayon fiber. Drip absorption sheet.