JP4205201B2 - Food packaging bag for microwave oven - Google Patents

Description

【００５２】
【表２】

【００５３】
【表３】

【００５４】
表１からは、本発明の電子レンジ用食品包装袋を用いた場合には、電子レンジで加熱した後もハンバーガーのおいしさが維持され、食感の低下がないことが示される。また食材がシートにくっつきにくく、剥がれやすいことが示される。
表２からは、本発明の電子レンジ用食品包装は、保水性に優れ、かつ濡れ戻りが少ないことが示される。
表３からは、本発明の電子レンジ用食品包装袋は、摩耗による毛羽立ち性に優れ、かつゴミの発生も少なく衛生的であることが示される。
【００５５】
【発明の効果】
本発明の電子レンジ用食品包装袋によれば、ハンバーガーなどを電子レンジで再加熱する際に発生する余分な水分や油分を取り、水分蒸発による食品の乾燥や硬化を防ぎ、水蒸気の結露やドリップによる食品のベタつき等を防止することができる。また、パンなどシートにくっつきやすい素材の食品もくっつかずにスムーズに取り出すことができ、再加熱の時に食品の食味を美味しく保つことができる。また食品への異物の混入を低減させられる。また電子レンジ加熱時の内圧により袋が弾けて内容物が電子レンジ内に飛び散るのを防止することができる。
【図面の簡単な説明】
【図１】本発明の一実施例を示す食品包装袋の説明図。
【図２】図１の食品包装袋に被包装物を挿入したときの断面説明図。
【図３】外装シート２と内層シート３の部分ラミネートの説明図。
【図４】部分ラミネートの図柄の一例を示す図。
【図５】本発明の他の実施例を示す食品包装体の説明図。
【図６】シール部に設けられる圧力逃し部の説明図。
【符号の説明】
１…食品包装袋、２…外装シート、３…内層シート、４…第２シート（窓部）５…接着部、６…非接着部、７…シール部、８…圧力逃し部、１０…被包装物。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a food packaging bag for a microwave oven, and more particularly to a food packaging bag for a microwave oven suitable for storing a hot dock, a hamburger or the like and reheating it in a microwave oven as it is.
[0002]
[Prior art]
In general, packaging bags for storing food that is reheated in a microwave oven before eating, such as hot dogs and hamburgers sold at convenience stores, etc., include paper, plastic film or plastic film composites. The material is used.
However, when food stored in a packaging bag made of such a material is heated in a microwave oven, steam is generated inside, and this steam does not escape to the outside, but remains inside and forms condensed water as a hot dock or hamburger. When the surface of the food becomes sticky on the food surface, and a large amount of condensed water is generated, the appearance of the food is deteriorated and the taste of the food is impaired.
[0003]
Further, the surface of the food packaging bag is usually provided with a pattern or a pattern, and the name of the food, how to eat, etc. are described, so that the stored food inside cannot be seen from the outside. Therefore, the purchaser simply needs to purchase by looking at the items described on the surface, and there is a drawback that it is easy to purchase food by mistake.
Various packaging bags have been proposed to solve such problems. For example, Utility Model Registration Publication No. 2555644 proposes a bag in which a sheet made of a nonwoven fabric and a pulp layer is used as an inner layer on the food side, another sheet is used as an exterior, and an air layer is formed between them. ing. However, in such a bag, it is necessary to further provide a pulp layer as a water absorption layer under the surface layer in contact with food, which causes problems such as a complicated bag structure and high cost. In addition, because pulp is used, there are disadvantages such as reduced heat-sealability when bag-making into bags and production speed is slow, and it is necessary to provide another thermal adhesive layer for this improvement. there were. In addition, the use of pulp or the like makes it easy to mix and generate garbage, which often causes problems as food packaging materials.
[0004]
Japanese Utility Model Publication No. 7-3909 proposes a bag with a window using a sheet composed of a moisture-permeable film for exterior and an oil-absorbent sheet for inner layer. However, in this bag, the water vapor released from the food can be expelled to the outside of the bag through the moisture permeable film, but for this reason, it is necessary to heat in the range for a long time. Water vapor generated in a large amount in time cannot be expelled to the outside quickly, and therefore, it has not been possible to prevent a decrease in food texture due to condensed water.
[0005]
Japanese Patent Application Laid-Open No. 8-80979 proposes using a perforated sheet as an inner layer. However, in the perforated sheet, dew condensation occurs at portions other than the perforated part, and therefore, the effect of removing the dew condensation water in the bag is insufficient.
Moreover, in Japanese Utility Model Laid-Open No. 3-108671, Japanese Patent Laid-Open No. 8-324654, Japanese Patent Laid-Open No. 4-57768, etc., a melt blown nonwoven fabric is provided alone on the surface material in contact with food, or a water absorbing layer such as pulp is provided in the inner layer. Proposed. The melt blown nonwoven fabric is composed of very thin fibers, and the sheet using the melt blown nonwoven fabric is also densified. However, when the moisture generated as water vapor condenses in the layer on the side that does not come into contact with food, good results can be obtained with little wetting back, but in reality the water vapor is condensed in the food packaging bag. There are overwhelmingly more. Therefore, the probability that moisture condensed on the food material side remains on the food material side increases, and the condensed water generated in the bag cannot be removed to the outside.
[0006]
In addition to the above proposals, various bags and sheets that maintain the freshness of food with condensed water generated by microwave heating have been proposed, but all use a general-purpose sheet as a surface material in contact with food. However, the use of a non-woven fabric that is clogged with water reduces the water absorption, and excess drip water is condensed at the interface between the food and the surface material. The return rate increases.
Further, it has been proposed to use a non-woven fabric made of an olefin fiber such as polypropylene, for example, by limiting the material of the surface material that comes into contact with the food from the viewpoint of food releasability and ease of taking out. However, only a general-purpose nonwoven fabric is used for these, which is insufficient in effect, and increases the rate of dew condensation water returning to food.
[0007]
[Problems to be solved by the invention]
The present invention solves the above-described problems of the prior art, effectively adsorbs and retains excess moisture and oil generated inside the bag without using pulp or the like as a water absorbing layer, and drip water for food. The present invention provides a food packaging bag for a microwave oven that can reduce rewetting.
[0008]
[Means for Solving the Problems]
The invention claimed in the present application is as follows.
(1) A packaging bag in which a sheet made of an exterior sheet and an inner layer sheet is formed into a bag shape so that the inner layer sheet is on the inner side, and the inner layer sheet has an irregular cross sectionofComposed of crimped fibersPolyolefin-based long fiber spunbondMade of non-woven fabric,The degree of irregularity of the nonwoven fabric constituting fiber is 1.2 to 2.5, and the number of crimps is 20 pieces / inch or more,A food packaging bag for a microwave oven, wherein an area of the inner layer sheet bonded to the exterior sheet is 20 to 70%, and a window portion through which the packaged body can be seen is provided in the packaging bag.
(2The exterior sheet is a sheet obtained by extruding and laminating a polyolefin resin for adhesion on the surface of paper (1) DescriptionFood packaging bags for microwave ovens.
(3) A packaging bag in which a sheet comprising an outer sheet and an inner layer sheet is formed into a cylindrical shape with the inner layer sheet inside, and the inner layer sheet has an irregular cross section.ofIt consists of a nonwoven fabric composed of crimped fibers,The nonwoven fabric is a polyolefin-based long fiber spunbond nonwoven fabric, the degree of irregularity of the nonwoven fabric constituting fibers is 1.2 to 2.5, and the number of crimps is 20 pieces / inch or more,Further, the area of the inner layer sheet bonded to the exterior sheet is 20 to 70%, and the cylindrical packaging bag has a window portion through which a packaged body can be seen, and at least one end of the cylindrical packaging bag. Sealing part andIs provided,Furthermore, the food packaging bag for microwave ovens provided with the pressure relief part in at least one of this seal part.
[0009]
According to the food packaging bag for a microwave oven of the present invention, since the non-woven fabric composed of crimped fibers with an irregular cross section is used as the inner layer sheet in contact with food, the bulkiness of the non-woven fabric is improved, and voids formed between the fibers Therefore, moisture and oil from water vapor condensation and drip generated when cooking and reheating food in a microwave oven can be adsorbed and retained in these gaps, and these can be used to rewet the food. It is possible to prevent the stickiness of food and the like and to prevent the food texture from deteriorating. Even when water-repellent polyolefin fibers are used for the nonwoven fabric, the generated moisture and oil can be adsorbed and held in a large number of voids formed in the nonwoven fabric, and the bread etc. can adhere to the sheet. It is possible to prevent the food in the packaging bag from being taken out smoothly. Furthermore, by providing a pressure relief portion at the seal portion of the packaging bag, it is possible to prevent the internal pressure from being increased due to water vapor generated during heating of the microwave oven, and the bag can be bounced so that the contents are not scattered into the microwave oven.
[0010]
Although the sheet | seat which consists of an exterior sheet and an inner layer sheet is used for the food packaging body for microwave ovens of this invention, the nonwoven fabric comprised by the crimp-like fiber by the irregular cross section is used for this inner layer sheet.
The exterior sheet used in the present invention may be any sheet as long as it does not significantly release excess oil or moisture generated inside when food is wrapped and heated in a microwave oven. For example, paper, sheets of paper with a thin coating of polypropylene or polypropylene resin, resin films such as polypropylene, polyethylene, polyester, polyamide, polyvinyl alcohol and the like, resin foams of these resins and polystyrene, flash spinning, etc. Examples thereof include a moisture permeable and waterproof nonwoven fabric.
[0011]
Heating the microwave oven heats the food itself, so it is difficult for heat to be transmitted as an exterior sheet from the point of taking out from the microwave oven or wrapping it in a sheet and eating it. A sheet in which moisture does not bleed out is preferable, and a sheet obtained by thinly coating paper with a polyolefin resin such as polypropylene or polypropylene resin is more preferable. At this time, the polyolefin resin of the coating layer may be used in consideration of the lamination with a polyolefin-based nonwoven fabric that becomes an inner layer described later.
[0012]
The basis weight and thickness of the exterior sheet is 10 to 100 g / m in terms of the appearance of the packaging, shape distortion, tears, mixing of garbage, etc.²The thickness is preferably 0.02 to 1 mm.
Further, the exterior sheet may be moisture permeable, or a part of the sheet may be perforated. These are more preferably selected according to the amount of water generated from the food used for the purpose of expelling excess water vapor heat-treated in the microwave oven out of the sheet or bag.
[0013]
The inner layer sheet used in the present invention is composed of a nonwoven fabric composed of crimp-like fibers with an irregular cross section, and the nonwoven fabric is preferably a nonwoven fabric composed of polyolefin fibers. Examples of such a polyolefin fiber material include monoolefin polymers such as ethylene, propylene, and butene, and polyolefin resins mainly composed of these copolymers. Moreover, the fiber which comprises these nonwoven fabrics may be a single component, or a mixed component. For example, a composite fiber in which polyethylene / polypropylene or the like is mixed may be used, or a composite product inside a single fiber, that is, a sheath-core fiber or a side-by-side fiber may be used. In the case of the new sheath type composite fiber, the material of the surface corresponding to the food may be a polyolefin as long as the sheath material is polyolefin, and the core material may be any. For example, fibers whose sheath / core is polyester / polypropylene, polyethylene / polyester or the like can be mentioned.
[0014]
Packaged items such as bread, hamburgers, and rice are made of starch and cellulosic materials, and these components are highly hydrophilic components. Therefore, when a hydrophilic paper product or the like is used as a packaging material, it has been necessary to perform a water-repellent treatment of paraffin or silicon to prevent adhesion with these, but a polyolefin-based material having low hydrophilicity is required. By using a non-woven fabric made of fibers, the peelability from food is improved, and there is no need for conventional treatment for preventing adhesion to food. In the present invention, it is possible to apply a water repellent to the nonwoven fabric surface in order to further increase the water repellency, but such a post-processing agent is detached during use or product processing and adsorbed to food. Since it may enter the human body, it is preferable not to apply it if possible.
[0015]
From the viewpoint of processability, nonwoven fabrics using polyolefin materials are also good in terms of secondary processability during use, such as heat sealability and bag-making properties. Furthermore, when heating in a microwave oven, the dielectric constant of polyolefin resin is low and dielectric loss is low compared to packaging bags using other polymers. It becomes possible to warm up.
[0016]
In the present invention, a crimp-like fiber having an irregular cross section is used as the fiber constituting the nonwoven fabric. Since the nonwoven fabric composed of such fibers has a bulky structure, the nonwoven fabric itself has a large number of voids, and moisture and oil on the fiber surface are adsorbed and retained in the voids. be able to. Therefore, it is possible to adsorb and retain excess moisture and oil generated from the food inside the nonwoven fabric, and to minimize wetting of excess drip water on the food.
[0017]
On the other hand, when a polyolefin-based material is used as the fiber material constituting the nonwoven fabric, since the polyolefin-based material is generally a water-repellent material, when water alone is dropped on these sheets, water droplets or Water will clump together and remain on the nonwoven fabric surface. Even in such a case, in the present invention, since the nonwoven fabric is kept bulky by using the crimp-shaped fibers with the above-mentioned irregular cross section, the water droplets can be adsorbed and held inside the nonwoven fabric, and it depends on moisture. The wetness of food can be effectively prevented. Therefore, in order to ensure the function of such a nonwoven fabric, it is preferable to appropriately select the bulk density, basis weight, fiber diameter, etc. of the nonwoven fabric within the range described later.
[0018]
The cross-sectional shape of the fibers constituting the non-woven fabric may be a circular shape that is not a perfect circle or an irregular shape such as Y-type, V-type, or W-type, but the specific surface area of the non-woven fabric is increased, and the fiber is easily manufactured. From the viewpoint of stable productivity and the like, the deformity is preferably 1.2 to 2.5, more preferably 1.5 to 2.5. By using such irregularly shaped fibers that are not perfect circles, the specific surface area of the fibers increases, and the area for adsorbing moisture and oil more increases. Moreover, the nonwoven fabric comprised with the irregular-shaped thread | yarn is easy to comprise the nonwoven fabric with a high porosity with high bulkiness by the yarn structure. Here, the degree of irregularity of the fiber is calculated by calculating the cross section and circumference (peripheral length) of the deformed yarn, then calculating the radius of the perfect circle having the same cross-sectional area, It is obtained by the following formula.
Deformation degree = circumference of deformed yarn / circumference of a perfect circle with the same cross-sectional area as the deformed yarn
[0019]
Crimp-like fibers are used as the fibers constituting the nonwoven fabric, and the number of crimps of the fibers is preferably 10 pieces / inch or more, more preferably 20 pieces / inch or more. If the number of crimps is less than 10 / inch, the free extension distance of each filament between the partial joining of the nonwoven fabric is shortened, the bulkiness as the nonwoven fabric is impaired, the effective fiber specific surface area is also reduced, and moisture and oil content are retained. Performance may be reduced. Although there is no restriction | limiting in particular in the upper limit of the number of crimps, generally it is difficult on manufacture to express the number of crimps 50 pieces / inch or more. By using such a crimp yarn, the bulkiness of the nonwoven fabric is increased, and excess water and oil content from the food can be retained.
[0020]
The filamentous crimp constituting the nonwoven fabric is expressed in a state where it is spun and accumulated on a collecting surface of a web conveyor or the like, even if it is a so-called latent crimp that is manifested by heating, stretching, solvent treatment, etc. after spinning. It may be a so-called manifested crimp. However, it is preferable that the crimp is obvious from the viewpoint that a dimensional change is unlikely to occur during the processing step, and a uniform sheet can be easily obtained with less occurrence of unevenness of the sheet.
The fibers constituting the nonwoven fabric may be used in combination with irregularly shaped cross-section fibers and / or crimp fibers. However, the use of crimp-shaped fibers with irregularly shaped cross-sections may increase the specific surface area and obtain a highly bulky nonwoven fabric. it can.
[0021]
In the present invention, the fineness of the single yarn of the fibers constituting the nonwoven fabric is preferably 0.3 to 50 denier, more preferably 0.5 to 20 denier. The specific surface area of the fiber is larger when the fiber denier is thinner, but if the fiber diameter is too small, the bulkiness of the nonwoven fabric may not be obtained even if the fiber is a deformed yarn or a crimped yarn. That is, when the fineness is less than 0.3 denier, the bulkiness of the non-woven fabric formed thereby is impaired, and as a result, moisture and oil are difficult to be held inside the densified non-woven fabric. Moreover, the area which a foodstuff contacts with the nonwoven fabric which is an inner layer sheet becomes large, and the wet-back of water may increase. Furthermore, the strength of the nonwoven fabric is insufficient, the sheet is torn due to friction or the like, or the fibers are cut off and fall off, which is likely to cause contamination of the foodstuff. In this respect, a melt blown nonwoven fabric and a flash spinning nonwoven fabric having a low fineness are not preferable. On the other hand, if the fineness exceeds 50 denier, a nonwoven fabric having a high bulkiness can be obtained. However, it is difficult to obtain deformed yarns and crimped yarns, which may make it difficult to manufacture.
[0022]
The basis weight of the nonwoven fabric used in the present invention is 8 to 60 g / m.²Is preferable, and more preferably 10 to 60 g / m.²More preferably, 15-40 g / m²It is. The basis weight is 8g / m²If it is less than the range, the ability to retain moisture and oil is reduced, and the sheet strength required for practical use and processing may not be obtained. On the other hand, 60 g / m²In the case where it exceeds 1, the sheet is too thick, the bag-making processability is deteriorated, and the product cost is increased, but the performance such as wettability may not be improved.
The bulk density of the nonwoven fabric is 0.01 to 0.2 g / cm from the point of adsorbing and retaining excess oil and moisture in the nonwoven fabric.^ThreeIs more preferable, and 0.05 to 0.12 g / cm is more preferable.^ThreeIt is. Bulk density is 0.2g / cm^ThreeIf it exceeds 1, bulkiness of the nonwoven fabric is lost, and excess moisture and oil may not be retained. Meanwhile, 0.01 g / cm^ThreeIf it is less than this, the production may be substantially difficult.
[0023]
As the nonwoven fabric, any of those obtained by a short fiber nonwoven fabric production method such as a card method or papermaking method or a long fiber nonwoven fabric production method such as a spunbond method can be used. In addition, as a method for bonding nonwoven fabrics, methods such as bonding with an adhesive, ultrasonic welder bonding, partial hot air bonding, and needle punch bonding can be used. However, for food applications, wear strength, dust and lint are generated. The method of partial thermocompression bonding is more preferable because it is difficult and there is no excess binder resin or glue.
The fibers constituting the non-woven fabric may be long fibers or short fibers, but long fibers are more preferable from the viewpoint of contamination of food by dropping off the short fibers, sheet strength and wear durability.
[0024]
In summary of the above points, the nonwoven fabric used in the present invention is preferably produced as follows. That is, a thermoplastic resin such as polypropylene is melt-spun, asymmetric cooling of the fiber is performed immediately after spinning to develop crimp, and the obtained continuous long fiber is laminated on a collecting surface of a web conveyor or the like to form a web. Then, the nonwoven fabric manufactured by the manufacturing method of what is called melt-spun spunbond which heat-joined by the hot embossing roll is preferable.
The nonwoven fabric may be applied with a food release agent or a release agent for easily peeling food, or may be imparted with antibacterial and antiseptic properties for maintaining the freshness of the food. In addition, processing for maintaining the freshness and texture of the food wrapped inside such as perforating processing for increasing bulkiness may be performed, but it is preferable to perform these appropriately depending on the purpose.
[0025]
In the present invention, the method of laminating the outer sheet and the inner layer sheet can be selected as appropriate, such as thermal bonding, bonding with an adhesive using a hot melt resin or a solvent, and a method of physically sewing, but an extra thing is interposed. Adhesion by heat is preferable in that it is not caused and productivity is good. For example, a method of laminating an outer sheet such as a film or paper and an inner layer non-woven fabric as it is, and a method of bonding the outer sheet and the inner layer non-woven fabric with an extrusion resin such as polyethylene or polypropylene interposed therebetween. At this time, paper may be used for the exterior, and a resin such as polyolefin may be thinly coated in advance for the purpose of heat sealing by heat.
[0026]
In the present invention, the area where the exterior sheet and the inner layer nonwoven fabric are bonded is 20 to 70%, preferably 30 to 60% from the viewpoint of maintaining the bulkiness and high specific surface area of the nonwoven fabric. It is preferable to appropriately control the area to be bonded within a range without impairing the above characteristics. In addition, for convenience when taking in and out the food, it is preferable that the outer sheet and the inner layer sheet are firmly bonded to each other at the end portion in the case of a sheet for packaging food and the entrance and exit portion when the sheet is formed into a bag shape.
[0027]
Examples of the method of partially bonding the outer sheet and the inner layer sheet include a method of using paper or the like as the outer sheet, and bonding this and the inner layer sheet by extrusion lamination such as polyolefin resin. The partial lamination is performed, for example, by extruding an extruded resin on the exterior sheet and / or the inner layer sheet, and then hot-pressing it through a hot roll using an uneven engraving roll. Manufacturing equipment for obtaining partial laminates having different area ratios to be bonded may be a heat embossing roll having unevenness as shown in FIG. 4 to be described later. Different sheets can be obtained. At this time, the hot embossing roll may be an embossing roll in which one or both rolls are uneven.
[0028]
When laminating the outer sheet and the inner layer sheet, care should be taken not to impair the voids formed in the non-woven fabric, that is, the high bulkiness and high specific surface area of the non-woven fabric that is the inner layer sheet. is necessary. For that purpose, it is preferable to adjust the pressure of the laminating roll at the time of processing by adhesion or lamination, so as not to apply excessive pressure to the nonwoven fabric as much as possible, and to reduce the engraving depth of the uneven hot embossing roll. What is necessary is just to determine suitably the pressure and conditions which are required for a lamination by the lamination equipment. The adhesive layer such as an extruded resin used for bonding is preferably 40 microns or less, more preferably 15 microns or less so that the extruded resin or the like enters the nonwoven fabric layer and does not crush the eyes of the nonwoven fabric.
[0029]
The food packaging bag for a microwave oven according to the present invention is formed into a bag shape so that the inner layer sheet of the nonwoven fabric described above is inside, and the packaging bag is provided with a window portion through which a packaged body can be seen. Yes.
The window portion provided in the packaging bag is not particularly limited in its form as long as the packaged body in the packaging bag can be seen from the outside. For example, a transparent bag is used to provide a belt-like window on the packaging bag, Or a rectangular window provided at the center of the packaging bag, or a portion of the packaging bag on which the inner layer sheet is not laminated is a window. By providing such a window on the packaging bag, the contents can be confirmed directly and purchased. When paper is used for the exterior sheet, the name of the contents, cooking method, processing method and processing date And information on food such as the expiration date can be written easily, and the purchaser can easily confirm these. In addition, it is expected to increase the atmosphere of eating with patterns and the like on the paper.
[0030]
The material used when using a transparent film for the window is not particularly limited as long as it is transparent and the contents can be confirmed, but it is a film that has been subjected to an antifogging process to prevent condensation on the film part. Preferably there is. A polyolefin-based resin film is preferable from the viewpoint of easy heat sealability with the inner layer sheet and the outer sheet. Furthermore, a minute hole that does not allow foreign matter such as dust and insects to be mixed in may be provided in a part of the film so that excess steam is discharged.
Moreover, there is no restriction | limiting in particular in the shape of a packaging bag, However, The shape which made the sheet | seat which consists of an exterior sheet and an inner layer sheet | seat cylindrical, and sealed the one end or both ends is preferable. Moreover, it is preferable to provide the seal part with a pressure relief part for releasing the internal pressure when heating the microwave oven to the outside.
Hereinafter, the present invention will be described in more detail with reference to the drawings.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an explanatory view of a food packaging bag showing one embodiment of the present invention.
FIG. 2 is a cross-sectional view of the food packaging bag shown in FIG.
1 and 2, the food packaging bag 1 includes a sheet obtained by laminating and integrating an outer sheet 2 and an inner layer sheet 3 so that the inner layer sheet 3 is inside, and both sides of the curved sheet in the length direction. It is comprised from the 2nd sheet | seat 4 which consists of a transparent resin film which melt | fused the both ends to the edge and formed a cylindrical body, and the seal part 7 which seals one end of this cylindrical body. The tubular body is provided with a gusset-like fold so that an article to be packaged can easily enter. The exterior sheet 2 and the inner layer sheet 3 are partially laminated with an adhesive or the like. Further, the seal portion 7 can be formed by a known method using heat fusion or an adhesive.
[0032]
FIG. 3 is an explanatory diagram of partial lamination of the exterior sheet 2 and the inner layer sheet 3, and FIG. 4 is a diagram illustrating an example of a pattern when partial lamination is performed.
In FIG. 3, an adhesive portion 5 and a non-adhesive portion 6 exist between both sheets, and an air layer is formed in the non-adhesive portion 6. The bonded portion 5 may be a portion that is thermocompression bonded without using an adhesive. Moreover, partial lamination can be performed by using a laminating roll having pattern irregularities shown in FIG. 4 (A) shows a pattern when 45% of the total area is partially laminated in a grid, (B) shows a pattern when 60% of the total area is partially laminated in a grid, and (C ) Shows a pattern in which 25% of the total area is partially laminated on the stripe.
In such a configuration, food is inserted from the unsealed opening of the cylindrical body of the food packaging bag 1, and then the opening is sealed with a tape or the like and heated in a microwave oven for serving. Is done.
[0033]
FIG. 5 is an explanatory view of a food packaging body according to another embodiment of the present invention.
5 is different from FIG. 1 in that seal portions 7 are provided at both ends of the cylindrical body to form a sealing bag, and a pressure relief portion 8 is provided in the seal portion 7.
The pressure relief portion 8 has a role of releasing the internal pressure to the outside when the internal pressure is increased by being heated in the microwave oven, thereby preventing the article to be packaged from bursting. As shown in FIG. 6, the pressure relief portion 8 can be provided by intermittently forming a sealed portion with a weaker strength between the sealed portions 7 sealed with a normal strength. . The seal portion 7 having the pressure relief portion 8 may be provided in advance at one end of the cylindrical body, or may be provided at the time of sealing after the article to be packaged is stored. The pressure relief portion 8 can be provided at one end or both ends of the cylindrical body. Moreover, you may provide in the seal part 7 of the package shown in FIG.
[0034]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
Example 1
Polypropylene is melt-spun from a nozzle having a V-shaped cross-section nozzle, the yarn is cooled from the side by a cooling device directly under the nozzle, pulled by air soccer, and has a square shape with an irregularity of 1.6. Continuous filaments having a crimp of .5 denier were obtained. The average number of crimps of this fiber was 25 / inch. The fibers are spread and dispersed to produce a web by depositing on a web conveyor, and the web is thermocompression bonded between an embossing roll and a flat roll having an embossed pattern interval of 4.5 mm with a crimping area ratio of 8%, and a basis weight of 20 g. / M²The crimp long fiber nonwoven fabric was obtained. The resulting nonwoven fabric has a bulk density of 0.089 g / cm.^ThreeMet.
[0035]
This nonwoven fabric and basis weight 40g / m²The paper was laminated and integrated by extrusion lamination to obtain a packaging sheet. At this time, the polylaminate resin was polypropylene, and the laminate thickness was 15 μm. The laminate area was 45% of the total area, and a lattice-like partial lamination method was adopted.
This laminated inner sheet is bent with the polypropylene nonwoven fabric side facing inward, and both side edges and a polypropylene antifogging film (thickness 40 μm) serving as a window are bonded together to form a cylindrical body. The product was folded in a gusset shape, and one end was sealed and closed to obtain a food packaging bag. Thereafter, a commercially available hamburger was put in, the opening was bent 2 cm, a part of the bent portion was stopped with a cello tape, heated in a microwave oven, and the taste and the like were evaluated by the method described later.
[0036]
Example 2
The same nonwoven fabric as in Example 1 was used and laminated and integrated in the same manner as in Example 1 to obtain a packaging sheet. However, at this time, the laminate area was 65% of the total area, and a lattice-like partial lamination method was adopted. A bag was made from the laminate sheet in the same manner as in Example 1, and evaluated in the same manner as in Example 1.
[0037]
Example 3
The same nonwoven fabric as in Example 1 was used and laminated and integrated in the same manner as in Example 1 to obtain a packaging sheet. However, at this time, the lamination area was 25% of the total area, and a stripe-shaped partial lamination method was adopted. A bag was made from the laminate sheet in the same manner as in Example 1, and evaluated in the same manner as in Example 1.
[0038]
Example 4
The same nonwoven fabric as in Example 1 was used and laminated and integrated in the same manner as in Example 1. However, at this time, the laminate area was 45% of the total area, and a lattice-like partial lamination method was adopted. Then, this laminated sheet is bent with the polypropylene nonwoven fabric side of the inner layer facing inward, and both sides of the both sides of the polypropylene antifogging film (thickness 40 μm) serving as the window portion are bonded together by fusing to form a cylinder. The body was further folded into a gusset shape, one end of which was sealed and closed, a commercially available hamburger was placed in the bag, and the opening was further sealed to form a sealed bag. However, at this time, the sealed portion that was sealed later was sealed by partially strengthening or weakening instead of uniform sealing strength in order to provide a pressure relief portion. The strength of the seal at this time was due to a partial pressure difference. The obtained sealed bag was heated in a microwave oven, and the taste and the like were evaluated in the same manner as in Example 1. In addition, it was observed that excess water vapor escapes from the portion where the sealing strength is weak when the microwave oven is heated.
[0039]
Example 5
Polyethylene / polypropylene sheath-core deformed short fibers are spread and dispersed by a card method and deposited on a web conveyor to produce a web, and the web is bonded to an embossing roll with an embossed pattern spacing of 4.5 mm at a crimping area ratio of 8%. Thermocompression bonding between flat rolls, basis weight 20g / m²The crimp long fiber nonwoven fabric was obtained. The bulk density of the obtained nonwoven fabric is 0.078 g / cm.^ThreeMet. The short fiber used had an elliptical shape with a fiber length of about 3.5 cm, a fiber diameter of 3.0 denier and an irregularity of 1.6, and an average of 20 crimps / inch.
This non-woven fabric was used as an inner layer sheet and laminated and integrated in the same manner as in Example 1 to obtain a packaging sheet. However, at this time, the laminating resin was polyethylene (thickness: 15 μm), the laminating area was 45% of the total area, and a lattice-like partial laminating method was adopted. A bag was made from the laminate sheet in the same manner as in Example 1, and evaluated in the same manner as in Example 1.
[0040]
Comparative Example 1
A commercially available polywrap was used as it was and used as a sample.
Comparative Example 2
Commercial paper instead of non-woven fabric (weight per unit 30g / m², Bulk density 0.633 g / cm^Three), This paper was used as an inner layer sheet, laminated and integrated in the same manner as in Example 1, and processed into a bag in the same manner as in Example 1 to obtain a food packaging bag. Thereafter, evaluation was performed in the same manner as in Example 1.
[0041]
Comparative Example 3
The same nonwoven fabric as in Example 1 was used as the inner layer sheet, and was laminated and integrated in the same manner as in Example 1 to obtain a packaging sheet. However, the whole was laminated at this time. Using this sheet, a bag was made in the same manner as in Example 1 and evaluated in the same manner as in Example 1.
Comparative Example 4
Polypropylene was melt spun from a perfect circle spout and pulled by air soccer to obtain 1.8 denier continuous long fibers. The fibers are spread and dispersed, and are deposited on a web conveyor to produce a web. The web is thermocompression bonded between an embossing roll and a flat roll having an embossed pattern interval of 1.0 mm with a crimping area ratio of 20%, and a basis weight of 20 g / m²The long fiber nonwoven fabric was obtained. The bulk density of the obtained nonwoven fabric is 0.150 g / cm.^ThreeMet.
This non-woven fabric was used as an inner layer sheet, laminated and integrated in the same manner as in Example 1, and processed into a bag in the same manner as in Example 1 to obtain a food packaging bag. Thereafter, evaluation was performed in the same manner as in Example 1.
[0042]
Comparative Example 5
In the same manner as in Example 1, a nonwoven fabric was obtained from a random fiber web containing 80% by weight of polyethylene terephthalate general-purpose fibers and 20% by weight of short rayon fibers. The bulk density of the obtained nonwoven fabric is 0.150 g / cm.^ThreeThe basis weight is 20 g / m²Met. The polyester short fiber used had a fiber length of about 3 cm and a fiber diameter of 2.0 denier, and the rayon short fiber used had a fiber length of about 3.5 cm and a fiber diameter of 1.4 denier. This nonwoven fabric was laminated and integrated in the same manner as in Example 1 to obtain a sheet.
This non-woven fabric was used as an inner layer sheet, laminated and integrated in the same manner as in Example 1, bag-formed as in Example 1, and used as a food packaging bag. Thereafter, evaluation was performed in the same manner as in Example 1.
[0043]
Comparative Example 6
Using the same laminated sheet as in Example 1, a sealed bag having both sides sealed in the same manner as in Example 4 was prepared. However, at this time, the seal part has the same seal strength on both sides. The sealed bag thus obtained was heated in a microwave oven, and the taste and the like were evaluated in the same manner as in Example 1. When the microwave oven was heated, the bag seen from the generated water vapor swelled, and the bag burst at once, and the moisture was scattered with the contents inside the microwave oven.
[0044]
Using the food packaging sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 6 (1) Hamburger test by microwave oven, (2) Drip water rewetting and moisture retention test of non-woven cloth inside the nonwoven fabric, (3 ) Generation of fuzz and lint due to abrasion of microwave packaging for hamburgers and (4) Bulk density of the nonwoven fabric were examined as follows, and the results are shown in Tables 1 to 3.
[0045]
(1) Hamburger test with microwave oven
A bag was made with a food packaging sheet (sample), and a commercially available hamburger was put in it, heated in a 600 watt microwave oven for 30 seconds, then taken out and tasted. Judgment evaluated three steps. The shape of the bag was 20 cm long and 15 cm wide, and when it was put on a microwave oven, the upper end was folded 5 cm and the folded mouth was fastened with tape. These were performed 5 points per sample, evaluated according to the following criteria, and the results are summarized in Table 1.
A: There was moderate moisture and it was very delicious.
○: Although the bottom of the bread was slightly wet, it was very delicious.
(Triangle | delta): Water | moisture content gathered at the bottom part of bread | pan, and it was not somewhat delicious.
X: Moisture gathered at the bottom of the bread and became crispy and was not delicious.
[0046]
Next, using the same bag, 1/2 sliced bread was placed in a bag, heated for 1 minute in a microwave oven, taken out of the microwave oven and left for 1 hour, and then the sensory evaluation of the degree of adhesion between the bread and the sample was performed. The operation was performed three times, and the evaluation was performed according to the following four-stage criteria. The results are summarized in Table 1.
A: The bread and the sample did not stick together and could be easily removed.
○: The bread and the sample did not stick, but it was difficult to take out.
(Triangle | delta): The bread and the sample have adhered a little, and when it forcibly removed, a little bread remained on the sheet | seat.
X: The bread and the sample adhered to each other, and when removed by force, the bread remained on the sheet.
[0047]
(2) Drip water rewetting and moisture retention test in nonwoven fabric
After putting 10cc of water and 20g of bread into a 300cc beaker, the mouth of the beaker (pore area 50cm²) A food packaging sheet (sample: 14 cm × 14 cm) is set with a rubber band. Then heat in a 600 watt microwave for 2 minutes. Immediately remove the sample from the microwave oven and measure the weight with a balance. Next, a filter paper (with a basis weight of 120 g / m) is placed on the sample.², Size 15 × 15 cm) was placed, a glass plate and a weight (1 kg) were placed thereon, the weight of the filter paper and the sample was measured after 10 seconds, and the following items A, B and C were obtained. The measurement was performed 5 times for each sample, and the average was obtained and summarized in Table 2. The calculation method is as follows.
[0048]
(1) Vapor generation adsorption amount: A
W₀0 Sample weight before microwave irradiation (mg)
W₁: Sample weight after microwave irradiation (mg)
Vapor generation adsorption amount: A (mg) = W₁-W₀
(2) Wetting return amount and wetting return rate: B
R₀: Weight of the first filter paper
R₁: Weight of filter paper after 10 seconds with sample and filter paper overlapped
Wetting back amount: B₁(Mg) = R₁-R₀
Wetting return rate: B₂(%) = [R₁-R₀/ A] × 100
(3) Sample water retention: C
W₀: Sample weight before microwave irradiation
W_Three: Weight of sample after 10 seconds with sample and filter paper overlapped
Residual amount of sample: C₁(Mg) = W_Three-W₀
Residual water ratio of sample: C₂(%) = [W_Three-W₀/ A] × 100
[0049]
(3) Measurement of the amount of lint, lint and dust from the nonwoven fabric
Food packaging sheet (sample: 16cm x 22cm) used as it is, and a sample that was worn at four places with a Gakushin-type wear machine as a wear durability test, left in a clean room (20 ° C x 65% RH) for 24 hours. After each sample was placed in a polyethylene bag (35 x 24 cm) in a clean room and shaken for 30 seconds, the fallen objects in the air in the polyethylene bag were counted for each particle size using a particle counter. And the amount of lint was measured. The measurement results are summarized in Table 3.
[0050]
(4) Measurement of bulk density of nonwoven fabric
Weight per unit area according to JIS-1906 (measurement conditions, peacock thickness type, pressurizer diameter 30 mm, load 5 g / m²) And measured by the following formula.
Bulk density (g / cm^Three) = Weight / Thickness
[0051]
[Table 1]

[0052]
[Table 2]

[0053]
[Table 3]

[0054]
Table 1 shows that when the food packaging bag for a microwave oven of the present invention is used, the deliciousness of the hamburger is maintained even after heating in the microwave oven, and there is no decrease in texture. In addition, it is shown that the food is difficult to stick to the sheet and easily peels off.
Table 2 shows that the food packaging for microwave ovens of the present invention is excellent in water retention and has little rewetting.
Table 3 shows that the food packaging bag for microwave ovens of the present invention is excellent in fuzzing property due to wear and is hygienic with little generation of dust.
[0055]
【The invention's effect】
According to the food packaging bag for a microwave oven of the present invention, excess moisture and oil generated when a hamburger and the like are reheated in a microwave oven are removed to prevent drying and hardening of the food due to moisture evaporation, condensation of water vapor and drip It is possible to prevent the stickiness of food due to. In addition, foods that are easy to stick to sheets such as bread can be taken out smoothly without sticking, and the taste of the food can be kept delicious during reheating. In addition, it is possible to reduce the mixing of foreign substances into the food. In addition, it is possible to prevent the bag from popping due to the internal pressure during heating in the microwave and causing the contents to splash into the microwave.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a food packaging bag showing an embodiment of the present invention.
FIG. 2 is a cross-sectional explanatory view when an article to be packaged is inserted into the food packaging bag of FIG.
FIG. 3 is an explanatory diagram of partial lamination of an exterior sheet 2 and an inner layer sheet 3;
FIG. 4 is a diagram showing an example of a partial laminate pattern.
FIG. 5 is an explanatory view of a food package showing another embodiment of the present invention.
FIG. 6 is an explanatory diagram of a pressure relief portion provided in a seal portion.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Food packaging bag, 2 ... Exterior sheet, 3 ... Inner layer sheet, 4 ... 2nd sheet (window part) 5 ... Adhesion part, 6 ... Non-adhesion part, 7 ... Seal part, 8 ... Pressure relief part, 10 ... Cover Packaging.

Claims (3)

A polyolefin-based long fiber spunbonded nonwoven fabric comprising a packaging bag in which a sheet comprising an outer sheet and an inner layer sheet is formed into a bag shape so that the inner layer sheet is on the inner side, wherein the inner layer sheet is composed of crimp-shaped fibers having an irregular cross section The nonwoven fabric constituting fiber has a degree of irregularity of 1.2 to 2.5, a number of crimps of 20 pieces / inch or more, and an area of the inner layer sheet bonded to the exterior sheet of 20 to 70%. And the food packaging bag for microwave ovens which provided the window part which can see a to-be-packaged body in the said packaging bag. The food packaging bag for a microwave oven according to claim 1 , wherein the exterior sheet is a sheet obtained by extruding and laminating a polyolefin resin for adhesion on the surface of paper. A packaging bag in which a sheet comprising an outer sheet and an inner layer sheet is formed into a cylindrical shape with the inner layer sheet inside, wherein the inner layer sheet is made of a nonwoven fabric composed of crimp-shaped fibers having an irregular cross section, and the nonwoven fabric is a polyolefin-based long It consists of a fiber spunbonded nonwoven fabric, the degree of atypicality of the nonwoven fabric constituting fibers is 1.2 to 2.5, the number of crimps is 20 pieces / inch or more, and the area bonded to the outer sheet of the inner layer sheet is 20 to 70% and in the tubular packaging bag, a window portion can be seen to be packaged body, and the seal portion is provided for sealing at least one end of the tubular packaging bag further the seal A food packaging bag for a microwave oven, wherein a pressure relief part is provided in at least one of the parts.

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