JP2000168791A - Food packaging sheet, and bag-shaped article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a void section comprising a non-bonded section between a water- absorbent sheet and an internal layer sheet, and prevent the stickiness or the like of a food due to dew condensation or dripping from occurring by bonding one surface of the water-absorbent sheet to an external packaging sheet by the whole surface, and at the same time, partially bonding the other surface of the water-absorbent sheet to the internal layer sheet. SOLUTION: This food packaging sheet 10 is constituted of an internal layer sheet 3 which comes into contact with a food and makes moisture or the like pass, a water- absorbent sheet 2 which absorbs the passed moisture or the like, and an external packaging sheet 1. In this case, the external packaging sheet 1 is wholly laminate- integrated with the water-absorbent sheet 2 at a bonding section 5, and in the meantime, the internal layer sheet 3 is partially bonded with the water-absorbent sheet 2, and the bonded section 5 and a non-bonded section 6 are formed between them. Then, moisture or the like generated from the food is quickly passed to the internal layer sheet 3, and is absorbed by the water-absorbent sheet 2, and at the same time, the absorbed moisture or the like, is suppressed to return to the food side through the internal layer sheet 3 by the existence of a void section comprising the non-bonded section 6, and the stickiness or the like of the food is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet and a bag for food packaging, and in particular, stores food such as rice, fried foods, hot dogs and hamburgers while hot, or re-packages the food with a microwave oven or the like. The present invention relates to a sheet for food packaging, which prevents the flavor of food from being impaired by excess moisture or oil coming out of the food when subjected to heat treatment, and is easy to take out the food, and a bag using the same.

[0002]

2. Description of the Related Art In general, hot docks, hamburgers, and the like sold at convenience stores, such as lunch boxes and fried foods sold at retail stores, etc., are containers (including bags, etc.) made of paper or plastic materials. In general, before eating these foods, the foods are re-heated by a microwave oven or the like while the foods are kept in containers or sheets. However, when heating in a microwave oven, steam is generated inside, and this steam stays inside without escaping to the outside and forms dew, and there is a problem that the dew water adheres to the surface of the food. The same was true when cooked food was placed in bags or sheets while hot.
Further, if the food is left in a container in which dew condensation water is generated, there is a problem that the food becomes sticky, the appearance is deteriorated, and the taste of the food is impaired.

In order to improve such a problem, various sheets using a nonwoven fabric or a liquid-permeable material have been proposed. For example, a sheet has been proposed in which an inner layer that is in contact with food has liquid permeability and a water-absorbing layer is laminated on the inner layer (see Japanese Utility Model Application Laid-Open No. Heisei 3).
-108671, JP-A-5-19171,
JP-A-5-305978, JP-A-7-13297
No. 4, JP-A-8-324654, etc.). This sheet is made permeable to the inner layer sheet that is in contact with food, and by arranging a water absorbing layer made of pulp or the like on the liquid permeable inner layer sheet, the generated dew condensation water passes through the inner layer sheet to the water absorbing layer. It is transferred and held to prevent dew condensation water from remaining on the inner layer sheet and to prevent wet back to the food surface.

[0004] However, in the above-mentioned sheet, since the inner layer sheet and the water absorbing layer are integrated, there is a drawback that the dew water once held in the water absorbing layer easily returns to the food side through the inner layer sheet. In particular, when the inner layer sheet has water absorbency or is made of a hydrophobic fiber material and has a low basis weight, the dew water retained in the water absorbing layer due to the capillary action between the fibers of the inner layer sheet is added to the food. There was a problem that it was easy to return.

Further, in order to prevent the wetting from returning from the water-absorbing layer to the inner layer sheet, there has been proposed a method of using a highly waterproof melt-blown nonwoven fabric for the inner layer sheet (Japanese Patent Laid-Open No. 3-2).
89455, JP-A-4-57768, JP-A-9-40033 and the like. These melt-blown nonwoven fabrics have the property that the constituent fibers are very fine and dense, so that they allow steam to pass but water is difficult to pass.
It has a function of preventing moisture retained in the water-absorbing layer from passing through the inner layer sheet and transferring to the food surface again. However, good results are obtained when the water vapor generated by heating the food is condensed in the water-absorbing layer that does not come into contact with the food.
Water vapor generated by heating food is overwhelmingly greater when dew forms inside the inner layer sheet, that is, on the food side. Therefore, the dew water generated inside the inner layer sheet cannot pass through the nonwoven fabric having a high waterproof property, and the probability of remaining on the food side increases, resulting in a rather bad result. From such a point, it is considered that an undensified sheet is preferable as the inner layer sheet in contact with the food.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to reduce the wetness of food such as dew condensation water (drip water) to reduce stickiness and flavor of food. It is an object of the present invention to provide a food packaging sheet and a bag-like material which can be prevented and can easily take out food.

[0007]

Means for Solving the Problems In view of the above problems, the present inventors have made intensive studies, and as a result, have found that a water absorbing layer that retains moisture,
By partially joining the inner layer sheet that comes into contact with food and providing a non-joining part (void) to structurally separate it, it is possible to prevent condensation of water vapor and stickiness of food due to drip, and a material that comes into contact with food By using a polyolefin material, it has been found that in addition to the above-mentioned effects, foods that easily adhere to sheets such as bread can be taken out smoothly, and the present invention has been achieved. That is, the invention claimed in the present application is as follows.

(1) A food packaging sheet comprising at least an exterior sheet, a water-absorbent sheet, and a liquid-pervious inner layer sheet, wherein the water-absorbent sheet has one surface entirely formed with the exterior sheet. A sheet for food packaging, wherein the sheet is joined and the other surface is partially joined to the inner layer sheet. (2) The bonding area ratio between the inner layer sheet and the water absorbent sheet is 1
(1) The food packaging sheet according to (1), wherein (3) The food packaging sheet according to (1) or (2), wherein the inner layer sheet is made of a nonwoven fabric composed of polyolefin fibers. (4) The food packaging sheet according to any one of (1) to (3), wherein the inner layer sheet is made of a nonwoven fabric by a long fiber spunbonding method. (5) A food packaging bag using the food packaging sheet according to any one of (1) to (4).

[0009]

FIG. 1 is a cross-sectional view of a food packaging sheet showing one embodiment of the present invention. In FIG. 1, a food packaging sheet 10 is a liquid-permeable inner layer sheet 3 that comes into contact with food and allows excess moisture and water vapor generated from the food to pass through.
And a water-absorbent sheet 2 that absorbs and retains moisture and the like that have passed through the inner layer sheet 3, and an exterior sheet 1. The exterior sheet 1 is entirely laminated and integrated at the joining portion 5 with the water-absorbing sheet 2, and the inner layer sheet 3 is partially joined to the surface of the integrated sheet on the water-absorbing sheet side, and A joint portion 5 and a non-joint portion 6 are formed between 3 and the water absorbent sheet 2. By wrapping the food with the inner layer sheet side inside using the food packaging sheet 10, moisture and the like generated from the food quickly pass through the inner layer sheet and are held by the water absorbent sheet 2, and the water absorbent sheet 2 The retained moisture has a non-bonded portion, that is, a void portion, between the inner layer sheet 3 and the water-absorbent sheet, so that it is suppressed from returning to the food via the inner layer sheet 3.

In the present invention, the exterior sheet prevents extra oil and moisture generated inside when the food is wrapped and heated in a microwave oven or the like from leaking to the outside. It has the role of preventing burns and the like when eating. Such an exterior sheet is not particularly limited as long as it has the above role.
Sheets of paper thinly coated with polyethylene or polypropylene resin, resin sheets of polypropylene, polyethylene, polyester, polyamide, polyvinyl alcohol, etc., or resin foam sheets of these resins or polystyrene, non-woven fabric obtained by flash spinning, etc. Examples thereof include a sheet and a sheet having moisture permeability and waterproofness such as a microporous film. Among these, a sheet obtained by thinly coating a sheet of paper with a polyolefin resin such as polyethylene or polypropylene resin is preferable from the viewpoint that heat is not easily transmitted and oil and moisture are prevented from oozing to the outside.

[0011] The exterior sheet may have moisture permeability,
For example, a part of a sheet may be perforated. It is preferable that the degree of the moisture permeability is appropriately selected according to the amount of water generated from the food for the purpose of driving out excess water vapor generated when heated by a microwave oven or the like to the outside of the sheet or the bag. The basis weight and thickness of the exterior sheet are from 10 to 100 g / m2 in view of the appearance of the package, prevention of breakage of the package, breakage, contamination of dust and the like, burn out of the food after heating and eating, and heat retention of the food. ^The thickness is preferably in the range of 0.02 to 1 mm. 10g / weight
When the thickness is less than m ² or the thickness is less than 0.02 mm, the mold is easily broken and easily broken. In addition, it is easy to burn when taking out or eating food after heating. If the basis weight exceeds 100 g / m ² , or if the thickness exceeds 1 mm, the heat sealing property at the time of bag making deteriorates and the cost tends to increase.

In the present invention, the water-absorbent sheet has a role of retaining moisture and the like that have passed through the inner layer sheet described later. Therefore, the water-absorbing sheet is not particularly limited as long as it is a sheet-like material having a water-absorbing property. For example, paper, a nonwoven fabric made of a natural fiber or a synthetic fiber, a sponge, or the like can be used. Among these, paper made of pulp and non-woven fabric made of cellulose fiber such as rayon are preferable from the viewpoints of water absorption, handleability, and price. Basis weight of the absorbent sheet is preferably 8~50g / m ^2, more preferably from 15 to 40 g / m ^2. If the basis weight is less than 8 g / m ² , the amount of water and water vapor absorbed is small, and excess water vapor is easily condensed on the food side, and the food is easily sticky. on the other hand,
If the basis weight exceeds 50 g / m ² , the sheet becomes thicker, the thermal conductivity is reduced, and it becomes difficult to adhere by heat. When it is processed into a sheet, or when processed into a bag such as a bag or a container, Workability may be reduced.

In the present invention, the inner layer sheet comes into contact with the food, allows water vapor and drip water, etc. generated from the food to pass through quickly without absorbing, and to be transferred to the water-absorbent sheet. It has a role of minimizing the wetting of the water and the like to the food side. As the inner layer sheet, it is only necessary that the inner layer sheet has liquid permeability that can transfer moisture generated under use conditions to the water absorbing sheet. In this respect, the water pressure resistance of the inner layer sheet is preferably 300 mm or less, more preferably. Is 150 mm or less. Examples of the material having excellent water vapor or drip water permeability include a nonwoven fabric made of a synthetic fiber such as polyethylene, polypropylene, and polyester, a nonwoven fabric made of a composite fiber thereof, a mesh-shaped knitted fabric and a woven fabric.
The use of a non-woven fabric made of a thermoplastic resin is advantageous at the time of sheet production or bag making.

In the present invention, a preferable inner layer sheet is a nonwoven fabric made of polyolefin fibers, and the fiber material constituting the nonwoven fabric is mainly composed of a monoolefin polymer such as ethylene, propylene, butene or a copolymer thereof. Polyolefin resin. The fibers constituting the nonwoven fabric may be a single component or a mixed component, for example, a composite fiber obtained by mixing polyethylene / polypropylene or the like, or a composite product in a single fiber, that is, a sheath-core fiber or a side-by-side fiber. Fiber or the like may be used. In the case of the sheath-core type composite fiber, the material of the surface corresponding to the food, that is, the material of the sheath may be a polyolefin,
The material of the core may be anything. Specifically, a composite fiber whose sheath / core is polypropylene / polyester, polyethylene / polyester, or the like is given.

[0015] Since the olefin fiber material has low hydrophilicity, by using a non-woven fabric made of the material as a food packaging material, when the food such as bread or hamburger is heated in a microwave oven, the food hardly adheres to the inner layer sheet. As a result, the food is easily taken out.
This is because bread, hamburgers, rice and the like to be packaged are mainly composed of starch and cellulose having high hydrophilicity. Furthermore, in order to improve water repellency or reduce hydrophilicity, the inner layer sheet surface was treated with paraffin or silicone based water repellent for the purpose of peeling when using paper products for food packaging. In the same manner as in the method described above, a water-repellent agent can be applied, but such a post-processing agent may be detached during use or product processing, adsorbed on food, may enter the human body, and come into contact with food. As the surface material of the inner layer sheet, it is preferable to use one composed of a polyolefin-based polymer alone.

The use of a polyolefin-based material is also preferable from the viewpoint of secondary workability such as heat sealing property and bag making property. In addition, when considering microwave compatibility, the polyolefin material has a lower dielectric constant and lower dielectric loss than other polymers, so the energy of the microwave oven can be effectively transmitted to the food and the food can be heated efficiently. It is also preferable from the viewpoint. In addition, the use of polyolefin-based material allows excess moisture generated from food, which is necessary for the inner layer sheet, to quickly pass through to the water-absorbent sheet side, and minimizes the drip of excess drip water on food. It is also preferable from the viewpoint of ensuring the function of suppressing the maximum. This is because the polyolefin-based material is a water-repellent material, and has the property of forming water droplets when water comes into contact with these sheets or of being solidified and remaining on the surface of the nonwoven fabric.

In the present invention, the fiber used for the inner layer sheet may be not only a round cross-section yarn, but also a flat or C-shaped or other modified cross-section yarn, or a crimped fiber. . Considering the role of the inner layer sheet in physically exposing the water-absorbing layer and the food, it is preferable to use irregularly shaped yarn or crimp yarn. In order to obtain the above properties of the inner layer sheet, it is preferable to appropriately select and use the basis weight, bulk density and fiber diameter of the nonwoven fabric used for the inner layer sheet.

The basis weight of the inner layer sheet is 5 to 50 g /
m ² is preferable, and more preferably 15 to 30 g / m ² . When the basis weight is less than 5 g / m ² , the thickness of the inner layer sheet becomes thin, the absorbent sheet easily comes into direct contact with the food, the moisture absorbed by the absorbent sheet easily returns to the food, and the food becomes sticky. Also, it may be difficult to manufacture the sheet. On the other hand, if the basis weight is more than 50 g / m ² , the thickness of the inner layer sheet becomes large, so that water vapor and moisture generated from the food are difficult to pass through, and the food is easily condensed on the food side to make the food sticky.

The bulk density of the inner layer sheet is from 0.01 to 0.01 from the viewpoint that excess oil and moisture generated from food can be quickly passed.
It is preferably in the range of 0.3 g / cm ^3, more preferably from 0.05 to 0.2 g / cm ^3. Bulk density is 0.3g
The Beyond / cm ^3, there is no loft between fibers,
The liquid permeability tends to decrease, while if it is less than 0.01 g / cm ³ , production may be difficult.

The average fineness of a single fiber of fibers used for the inner layer sheet is preferably from 0.1 to 50 denier, more preferably from 0.5 to 20 denier, from the viewpoint of liquid permeability. If the average fineness is less than 0.1 denier, the sheet is densified, so that the liquid permeability is reduced, and the wetting of water from the water-absorbent sheet due to the capillary phenomenon is increased. In addition, since the contact area between the food and the inner layer sheet is increased, the food easily adheres to the inner layer sheet, the strength of the nonwoven fabric is insufficient, the sheet is broken by friction or the like, the fibers are easily cut, and the food is contaminated. It will be easier. On the other hand, if the fineness exceeds 50 denier,
It may be substantially difficult to manufacture.

As the nonwoven fabric used for the inner layer sheet, any nonwoven fabric produced by a short fiber nonwoven fabric production method such as a card method or a papermaking method or a long fiber nonwoven fabric production method such as a spun bond method can be used. The fibers forming the nonwoven fabric may be long fibers or short fibers, but long fibers are more preferable from the viewpoint of preventing foreign matter from being mixed into food due to falling off of the short fibers, strength of the sheet and durability against abrasion. In addition, bonding of non-woven fabric includes bonding with an adhesive, ultrasonic welding, partial hot air bonding,
Although a method such as needle punch bonding can be adopted, a method of partial thermocompression bonding is most preferable because wear strength, dust and lint are less likely to be generated, and no extra connection resin or glue is used. Taken together,
As the nonwoven fabric used for the inner layer sheet, it has good abrasion resistance,
From the viewpoint that lint and the like are not easily transferred to food, a long fiber type spunbonded nonwoven fabric is more preferable. A composite nonwoven fabric such as SMS using a spunbonded nonwoven fabric can also be used. The fiber forming the nonwoven fabric for the inner layer sheet in the present invention may be not only a round cross section, but also a flat or irregularly shaped yarn such as a C type, or a crimped fiber or the like. In consideration of the purpose of using the inner layer sheet, which physically separates the food from the layer that has absorbed the dew condensation water, it is more preferable to use a deformed yarn or a crimp yarn as the fiber used for the inner layer sheet.

In the present invention, the exterior sheet and the absorbent sheet are integrally joined by bonding over the entire surface. The integration of these sheets can be carried out by extrusion lamination of resin, heat bonding, lamination with an adhesive using a hot melt resin or a solvent, etc. From the viewpoint of good properties, heat bonding is preferred. For example, a method of laminating an exterior sheet made of a film or paper and a water-absorbing sheet made of a nonwoven fabric as it is, a method of laminating with an extruded resin such as polyethylene or polypropylene interposed therebetween, and the like can be mentioned. When paper is used for the outer layer, it is preferable to coat a thin film of a resin such as polyolefin in advance in order to facilitate heat sealing by heat. The purpose of joining the water-absorbent sheet entirely with the exterior sheet is to prevent excess moisture once absorbed from returning to the food side through the inner layer sheet. That is,
If the water-absorbent sheet is improperly fixed to the exterior sheet side, the water-absorbent sheet containing moisture tends to stick to the inner-layer sheet side, which makes it easy to get wet. For this reason, it is necessary that the exterior sheet and the water-absorbent sheet are entirely bonded and integrated, and the joint area ratio between the exterior sheet and the water-absorbent sheet is preferably 70% or more, more preferably 85%.
That is all.

In the present invention, the surface of the integrated sheet on the side of the water-absorbent sheet is partially joined to the inner layer sheet. The joint area between the inner layer sheet and the water-absorbent sheet physically separates the water-absorbent sheet that has absorbed moisture and the inner layer sheet that comes into direct contact with the food, so that the moisture and the like from the water-absorbent sheet can return to the food. From the viewpoint of prevention, it is preferably as small as possible, and in the present invention, it is preferably in the range of 1 to 70%, more preferably 3 to 60%. If the bonding area ratio is less than 1%, the inner layer sheet and the water-absorbing sheet tend to peel off. That is, it is only necessary that the water-absorbing sheet and the inner layer sheet are integrated at the time of use, and the end of the sheet and the mouth of the bag may be joined to such an extent that the inner layer sheet does not peel off at the time of use. Further, when the bonding area of the inner layer sheet exceeds 70%, the moisture retained in the water-absorbing layer tends to wet back. In addition, it is preferable that the integrated sheet and the inner layer sheet are firmly joined at the end portions of both sheets or the opening and closing portion in the case of a container or bag shape for convenience of taking in and out of food.

The partial bonding between the inner layer sheet and the water absorbing sheet is as follows:
The bonding can be performed by the same method as the bonding method when the exterior sheet and the water-absorbent sheet are integrated. The preferable bonding method is heat bonding for the same reason. Partial joining of the two sheets, for example, by applying an extruded resin on the water-absorbent sheet or the inner layer sheet of the integrated sheet, superimposing both sheets, passing between the hot rolls using an uneven engraving roll It can be performed by hot pressing. Such partial joining can be performed simultaneously when a container or a bag is manufactured using both sheets as described later. The bonding area can be adjusted by appropriately selecting the area of the convex portion or the concave portion of the hot embossing roll. The hot embossing roll at this time may be an embossing roll in which one or both rolls are uneven.

The food packaging sheet of the present invention may be used by wrapping food in a sheet state, or may be used by processing the sheet into a bag-like material such as a container or a bag. The final use form is appropriately selected depending on the use situation and purpose of the user, but in reheating in a microwave oven etc., to give the food a plump finish with a suitable sealing property, it is easy to handle and In order to prevent entry of insects, foreign substances, and the like, it is preferable to use the material after processing into a bag-like material such as a container or a bag.

When used after processing into a bag-like material, the container or bag can be appropriately devised. For example, a window can be provided so that the packaged object, which is the food inside, can be seen. This window portion may be any type as long as the packaged object can be seen, for example, a band-shaped window, a circular or square window provided in the center of the sheet, a transparent film used as a part of the bag, and the like. Is mentioned. Further, a minute hole or the like for letting out excess steam when the bag is formed may be provided, and a fastener or the like may be provided for further improving the sealing performance. A notch or the like may be provided in order to easily break the bag.

FIG. 2 is an explanatory view of a bag for food packaging showing one embodiment of the present invention. The food packaging bag comprises a food packaging sheet 10 and a transparent resin film 7. The food packaging sheet 10 is prepared in advance by using the exterior sheet 1
And the water-absorbent sheet 2 are completely joined at the joint 5, and then the other surface of the water-absorbent sheet 2 and the inner layer sheet 3 are partially joined, and the joint 5 is substantially formed between the two sheets. It is obtained by forming the non-joining portion 6 forming the void portion, and the partial joining at this time is performed simultaneously when the integrated sheet and the inner layer sheet are overlapped and processed into a bag shape. In other words, an integrated sheet consisting of an exterior sheet and a water-absorbent sheet is prepared in advance, and the inner layer sheet is superimposed on the water-absorbent sheet side so as to be in contact with the inside of the water-absorbent sheet, and is processed into a bag shape by thermal bonding. Done. By partially joining at the same time during the bag making process, only the end of the inner layer sheet can be joined to the water absorbent sheet,
Since the area of the non-joined portion 6 between the inner layer sheet 3 and the water-absorbent sheet 2, that is, a large number of voids, is formed, it is possible to reduce the return of moisture and the like from the water-absorbent sheet 2 to the food side. . The transparent resin film 7 has both ends fused to both side edges of the food packaging sheet 10 folded in a gusset shape so that the inner layer sheet 3 is on the inside, and forms a window in the food packaging bag. One end of a cylindrical bag formed of the food packaging sheet 10 and the transparent resin film 7 is heat-sealed, and the other is a food outlet.

[0028]

The present invention will be described in more detail with reference to the following examples. Example 1 Pure white paper (basis weight 40 g / m ² ) as an exterior sheet and pulp paper (basis weight 18 g / m ² ) as a water-absorbing sheet were entirely laminated and integrated by extrusion lamination. At this time, a modified polypropylene resin was used for the extrusion lamination,
Its thickness was 15 μm. Next, a polypropylene spunbonded nonwoven fabric (20 g / m
² , the bulk density of 0.12 g / cm ³ ) was partially heat-sealed on the water-absorbent sheet side of the integrated sheet prepared above to obtain a sheet for food packaging. The bonding area ratio at this time is 25%
And partially laminated in a lattice. Next, a gusset bag with a window having the shape shown in FIG. 2 was prepared using a food packaging sheet. The shape of the bag is 21 cm in length, 12 cm in width, has a gusset part of 6 cm, and forms a window with a width of 8 cm on the upper surface of the bag with a polypropylene anti-fog film, and further heat seals one end of the cylindrical bag. The end was an entrance.

Example 2 In Example 1, the partial laminate of the integrated sheet and the inner layer sheet, in which the exterior sheet and the water-absorbent sheet were joined together, was heat-sealed at once at the time of bag making so that only the end of the food packaging sheet was used. A gusset bag with a window was obtained in the same manner as in Example 1 except that partial joining was performed. This bag had a laminated structure of an integrated sheet and an inner layer sheet except for the window portion. The inner layer sheet was bonded to the integrated sheet only at the window portion and the back portion, and the bonding area ratio was 4%.

Example 3 A food packaging bag was prepared in the same manner as in Example 1 except that the bonding area ratio of the inner layer sheet was changed to 45%. Example 4 In Example 1, a polyester spunbonded nonwoven fabric (having a basis weight of 20 g / m ² and a bulk density of 0.2) was used as the inner layer sheet.
A food packaging bag was prepared in the same manner as in Example 1 except that 2 g / cm ³ ) was used.

Example 5 In Example 1, as the inner layer sheet, a polypropylene spunbonded nonwoven fabric (having a basis weight of 12 g / m ² and a bulk density of 0.1 g / m ^{2) was used} .
A food packaging bag was prepared in the same manner as in Example 1 except that 14 g / cm ³ ) was used. Example 6 In Example 1, a composite nonwoven fabric made of polypropylene was used as the inner layer sheet (spunbond nonwoven fabric + melt-blown nonwoven fabric + spunbond nonwoven fabric).
In m ² , each basis weight is 7 g / m ² +3 g / m ² +
A food packaging bag was prepared in the same manner as in Example 1 except that 7 g / m ² and an overall bulk density of 0.14 g / cm ³ ) were used.

Example 7 In Example 2, a dry short-fiber nonwoven fabric (short fibers made of polypropylene + short fibers made of rayon) was used as the inner layer sheet. The total basis weight was 20 g / m ² , and the ratio of each material was 50%.
A food packaging bag was obtained in the same manner as in Example 2 except that the weight% and the bulk density were 0.18 g / cm ³ ). Example 8 A food packaging bag was prepared in the same manner as in Example 1 except that the bonding area ratio of the inner layer sheet was changed to 80%.

Comparative Example 1 In Example 1, a food packaging bag having the same shape as in Example 1 was produced using a commercially available polypropylene film as a food packaging sheet. The entire bag was made of this sheet without using the window film. Comparative Example 2 In the same manner as in Example 1, except that the outer sheet and the inner layer sheet were directly bonded without using the water-absorbent sheet, and partially laminated in a lattice so that the bonding area ratio became 25%. A food packaging bag was prepared.

Comparative Example 3 In Example 1, a water-absorbing paper (Newsoflon F manufactured by Unicharm Co., Ltd.)
X, the basis weight was 22 g / m ² ), and a food packaging bag was produced in the same manner as in Example 1 except that the laminate was partially laminated in a grid pattern so that the bonding area ratio was 25%. Note that a water-repellent sheet was not used in this bag. Comparative Example 4 In Example 1, the water-absorbent sheet and the inner layer sheet were entirely joined by heat sealing to be integrated. Further, an exterior sheet was attached to the surface of the water-absorbent sheet of the integrated sheet, and the joint area ratio was 25.
%, And a food packaging bag was prepared in the same manner as in Example 1 except that partial lamination was performed in a grid pattern so as to obtain the percentage.

Comparative Example 5 In Example 1, a nonwoven fabric made of a melt blow method made of polypropylene was laminated and integrated with the water absorbent sheet by heat sealing as an inner layer sheet, and an exterior sheet was joined to the surface of the water absorbent sheet of the laminated sheet. A food packaging bag was produced in the same manner as in Example 1 except that the laminate was partially laminated in a grid shape so that the ratio became 25%. Comparative Example 6 In Comparative Example 5, the integrated sheet obtained by joining the water-absorbent sheet and the inner layer sheet, and the outer sheet were heat-sealed at once at the time of bag making without partial lamination in advance, and had the same shape as in Example 1. A food packaging bag was obtained. This bag is
Except for the window part, it has a laminated structure of an integrated sheet and an exterior sheet, and the exterior sheet is bonded only at the window and back,
The bonding area ratio at this time was 4%.

<Test Examples> Examples 1 to 8 and Comparative Examples 1 to
The following evaluation was performed about the food packaging bag obtained in 6. (1) Hamburger test by microwave oven Put a commercially available hamburger in the obtained bag (sample)
The mixture was heated in a microwave oven of 00 watts for 30 seconds and then taken out to determine the taste (deliciousness). The judgment was made in the following four stages. In addition, when placed in a microwave oven, the upper end of the bag was bent by 3 cm, and the bent mouth was closed with tape. This evaluation was performed at five points per sample, and the averaged results are shown in Table 1. Judgment criteria ◎: Moderate water content and very delicious. ：: The bottom of the bread was slightly wet, but delicious. Δ: Moisture gathered at the bottom of the bread and was slightly unsatisfactory. X: Moisture gathered at the bottom of the bread and became crunchy and not delicious.

Further, 1/2 of the sliced bread was put in each bag, heated in a microwave oven for 1 minute, taken out of the microwave oven and left for 1 hour, and the degree of sticking of the bread and the sample was evaluated organoleptically. The operation was performed three times, and the judgment was evaluated in the following four stages, and the results are shown in Table 1. Judgment criteria ：: The bread and the sample did not stick, and the sample was easily removed. ：: The bread and the sample did not stick, but there was some difficulty in removing the sample. Δ: The bread and the sample were slightly attached to each other, and when the sample was forcibly taken out, a little bread remained in the sample. ×: The bread and the sample adhered to each other. When the bread was forcibly taken out, a considerable amount of bread remained on the sheet.

[0038]

[Table 1]

Table 1 shows that, even when the food packaging bag obtained in the present invention is used and heated in a microwave oven, the taste of the food is maintained, and it is hard to stick to the food and easy to take out.

(2) Drip water re-wetting and moisture retention test in nonwoven fabric A filter paper soaked with 10 cc of water was placed in a 300 cc beaker, and a sample (laminated sheet) was inserted into the mouth (pore area: 50 cm ² ) of the beaker. : 14 cm x 14 cm, those that were attached at the time of bag making were disassembled and used as evaluation sheets) and set with rubber bands. Thereafter, the sample was heated in a microwave oven of 600 watts for 2 minutes, and the sample was taken out of the microwave oven into a room at a constant temperature and humidity (20 ° C., 65% rh). After 15 minutes and 30 minutes, the sample was removed. Was measured. Next, a filter paper (basis weight 120 g / m ^2, size 15 cm × 15 cm) was placed on the sample, a glass plate and a weight (1 kg) were placed thereon, and after 10 seconds, the weight of the filter paper and the sample was measured. The following items were calculated. The measurement was performed five times for each sample, and the results were averaged and shown in Table 2.

Vapor generation adsorption amount A (mg) = W ₁ −W ₀ W ₀ Sample weight (mg) before heating in microwave oven W ₁ : Sample weight (mg) after heating in microwave oven Wet return amount B ₁ and return to wetness Rate B ₂ Wet return amount B ₁ (mg) = R ₁ −R ₀ Wet return rate B ₂ (%) = [(R ₁ −R ₀ ) / A] × 10
0 R ₀ : initial weight of filter paper R ₁ : weight of filter paper 10 seconds after the sample and filter paper were stacked Sample water retention C ₁ and water retention C ₂ Water retention C ₁ (mg) of sample = W ₂ -W ₀ Water retention of sample C ₂ (%) = [(W ₂ −W ₀ ) / A] × 1
00 W ₀ : Weight of sample before microwave heating W ₂ : Weight of sample 10 seconds after sample and filter paper

(3) The basis weight, thickness, and bulk density of the nonwoven fabric were determined by the following methods. The basis weight (g / m ² ) and thickness (mm) (measurement conditions: Peacock thickness gauge, pressurizer; diameter 30 mm, load 5 g / cm ² ) were measured according to JIS L 1906, and determined by the following formula. Bulk density (g / cm ³ ) = (weight / thickness) × 100,000 (4) The bonding area ratio was determined by the following method. The water-absorbent sheet and the inner layer sheet or the water-absorbent sheet and the outer sheet are peeled off, and the surface of the inner layer sheet or the outer sheet in contact with the water-absorbent sheet is photographed with a microscope. Then, the area ratio (%) of the bonded portion is determined from the ratio between the bonded portion and the non-bonded portion, and this value is defined as the bonded area ratio.

[0043]

[Table 2] A: Absorbed adsorption amount (mg) C ₁ : Water retention amount of sample (mg) B ₁ : Wet return amount (mg) C ₂ : Water retention ratio of sample (%) B ₂ : Wet return ratio (%)

From Table 2, it is shown that the food packaging sheet of the present invention has a small amount of re-wetting after heating in a microwave oven and a large amount of water retention by the water-absorbent sheet.

[0045]

According to the food packaging sheet and the bag-like material of the present invention, excess moisture and oil generated when a hamburger or the like is reheated in a microwave oven are removed, and the drying and hardening of the food due to the evaporation of moisture is achieved. Thus, it is possible to prevent the food from sticking due to condensation of water vapor and drip. In addition, foods of a material that easily sticks to a sheet such as bread can be taken out smoothly without sticking to the sheet, and the taste of the food after reheating can be kept delicious.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a food packaging sheet according to an embodiment of the present invention.

FIG. 2 is an explanatory view of a bag for food packaging according to one embodiment of the present invention.

[Explanation of symbols]

1: exterior sheet, 2: water absorption sheet, 3: inner layer sheet,
5 ... bonded part, 6 ... non-bonded part, 7 ... transparent resin film, 1
0: Food packaging sheet

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Ryujiro Yoshino 1-2-6 Dojimahama, Kita-ku, Osaka-shi, Osaka Asahi Kasei Kogyo Co., Ltd. F term (reference) 3E064 AA13 BA24 BB03 BC06 BC20 EA17 EA18 FA01

Claims (5)

[Claims] 1. A food packaging sheet comprising at least an exterior sheet, a water-absorbent sheet, and a liquid-permeable inner layer sheet, wherein the water-absorbent sheet has one surface entirely bonded to the exterior sheet. Wherein the other surface is partially joined to the inner layer sheet. 2. The food packaging sheet according to claim 1, wherein a bonding area ratio between the inner layer sheet and the water absorbent sheet is 1 to 70%. 3. The sheet according to claim 1, wherein the inner layer sheet is made of a nonwoven fabric composed of polyolefin fibers.
Or the food packaging sheet according to 2. 4. The inner layer sheet is made of a nonwoven fabric by a long fiber spunbond method.
Food packaging sheet according to any one of the above. 5. A bag for food packaging, comprising the food packaging sheet according to claim 1.