JP4978077B2 - Microwave packaging bag - Google Patents

Description

  The present invention relates to an opening for releasing steam generated from contents such as food when cooking the contents using a microwave oven with the contents such as food stored in a sealed packaging bag. The present invention relates to a microwave packaging bag that can be automatically formed in a packaging bag and can discharge steam from the opening to prevent the contents from blowing out and the packaging bag from bursting.

  Contents such as food that can be cooked using a microwave oven in a state where contents such as food are stored are stored in a packaging bag and are commercially available. When this type of microwave packaging bag is cooked using a microwave oven, the internal pressure in the packaging bag increases due to the steam generated from the contents, eventually bursting, and the contents are scattered in the microwave oven, There is a problem of dirtying the inside of the cabinet, and various ideas have been made to prevent this.

  For example, a bag made by heat-sealing with a sealant layer arranged opposite to each other, with a part of the heat-sealed portion of the bag having a thin film (such as easy peel tape) interposed between the sealant layers In addition, the heat seal strength of the thin film interposed seal portion is made smaller than the heat seal strength of the non-thin film interposed seal portion, and a part of the thin film interposed seal portion is heat sealed. A packaging bag formed on a narrow and narrow seal portion has been proposed (see, for example, Patent Document 1), and by providing a weak portion in a part of the heat seal portion for sealing, an electronic When cooking in the range, the internal pressure in the packaging bag rises due to the steam generated from the contents, the weak part of the heat seal part peels off, and the inside and outside of the packaging bag Wants hole occurs, packaging bag vapors to escape to the outside has been proposed (e.g., see Patent Document 2).

  However, the packaging bag disclosed in Patent Document 1 is a state in which a thin film interposed seal portion is partly disposed on a heat seal surface with a thin film (easy peel tape or the like) interposed, and a narrow seal portion having a narrow heat seal width. Since the above-mentioned thin film is originally formed to facilitate peeling, there is a risk of peeling from the heat seal surface due to pressure or impact applied during normal transportation or storage. In addition, there is a problem that the manufacturing process becomes complicated and the cost increases.

  Moreover, since the packaging bag disclosed by patent document 2 is a packaging bag which provides a part with a weak intensity | strength in a part of sealing part for sealing, at the time of normal transport and storage similarly to the packaging bag of patent document 1 There is a risk of peeling from the heat seal surface due to applied pressure or impact.

  In addition, the applicant of the present invention previously has a resin layer between the heat-resistant base material layer and the sealant layer that has a predetermined strength in a temperature environment of room temperature or lower, but has a predetermined strength that decreases in a high temperature environment. There has been proposed a microwave oven-compatible packaging bag that is provided in at least one region and that crosses at least one region of the heat seal portion in a direction perpendicular to the heat seal portion (see, for example, Patent Document 3).

The microwaveable packaging bag shown in Patent Document 3 is capable of automatically relieving internal pressure increased by steam generated from the contents due to the effect of providing the resin layer by cooking with a microwave oven. For example, in the case of a high-power microwave oven such as a commercial microwave oven (1600 W), the timing when the internal pressure is increased by steam or the like and the resin layer is softened by heat, resulting in a laminate strength. There is a risk of misalignment with the timing at which the temperature drops, and in extreme cases there is a risk of rupture and contamination of the contents of the microwave oven with the contents. Therefore, there is a demand for a packaging bag that has no risk of bursting. As a result of various researches to meet this demand, a further heat factor is added to the packaging bag as a component. And it found that meet the Nozomu in which the present invention has been accomplished.
Japanese Patent Laid-Open No. 10-59433 Japanese Patent Laid-Open No. 10-59431 JP 2000-190912 A

  Therefore, the present invention is a microwave oven packaging bag in which the opening is surely automatically formed by cooking regardless of the type of microwave oven, and the rising internal pressure can be smoothly released from the opening and is not ruptured. Furthermore, it is to provide a packaging bag for a microwave oven that does not break due to force majeure pressure or impact applied during normal transportation or storage.

In order to achieve the above-mentioned object, the inventor of the present invention described in claim 1 forms a laminate including at least a base material layer and an inner layer made of a heat-adhesive resin to produce an edge heat-bonding portion. A packaging bag for a microwave oven sealed with the edge thermal bonding portion between the base material layer and the inner layer of the laminated body on one side constituting the edge thermal bonding portion. A laminate strength adjustment region composed of a laminate strength adjustment layer is formed that traverses from the inside to the outside of the bag, and at least part of the laminate strength adjustment region is formed between the base material layer and the laminate strength adjustment layer. When the conductive heat generating layer is formed so as to be applied to the laminate, the laminate strength adjusting layer and the conductive heat generating layer are sandwiched between the base material layer and the inner layer. .

Further, the present invention according to claim 2 is a microwave oven packaging bag in which a laminate including at least a base material layer and an inner layer made of a heat-adhesive resin is formed and sealed at an edge heat-bonding portion. The edge thermal adhesive portion is traversed from the inside to the outside of the packaging bag between the base material layer and the inner layer of the laminate on one side constituting the edge thermal adhesive portion. A laminate strength adjustment region composed of a laminate strength adjustment layer is formed, and a conductive heating layer is formed between the base material layer and the laminate strength adjustment layer so as to cover at least a part of the laminate strength adjustment region. Thus, the laminate strength adjusting layer and the conductive heat generating layer are sandwiched between the base material layer and the inner layer, and the conductive heat generating layer is formed by printing with an ink containing at least carbon black. Oh It is characterized in that and the surface resistivity is 10 [Omega / □ or more 10 ⁷ Ω / □ or less.

Moreover, the present invention according to claim 3 is the packaging bag for microwave oven according to claim 1 or 2 , wherein the conductive heat generating layer has the edge thermal bonding portion from the inside of the packaging bag. It is characterized by being formed so as to cross outward .

According to a fourth aspect of the present invention, in the microwave oven packaging bag according to the third aspect , the conductive heating layer is formed so as to substantially coincide with the laminate strength adjustment region. It is.

The present invention according to claim 5 is the microwave oven packaging bag according to any one of claims 1 to 4 , wherein the laminate strength adjusting layer is an ethylene-vinyl acetate copolymer having a melting point of 60 to 90 ° C. It is made of a resin mainly composed of any one of a polymer resin, a polyamide-nitrified cotton-based resin, and a polyamide-nitrified cotton-polyethylene wax-based resin .

  The microwave oven packaging bag of the present invention comprises a laminate comprising at least a base material layer and an inner layer made of a heat-adhesive resin, and a laminate strength adjusting layer is provided between the base material layer and the inner layer, By adopting a configuration in which a conductive heating layer is provided in the laminate strength adjustment region where the laminate strength adjustment layer is provided, the heat of steam generated from the contents of food, etc. during cooking with a microwave oven is sufficiently applied to the laminate strength adjustment layer. Even if it is not transmitted, the conductive heat generating layer generates heat, and the heat softens the laminate strength adjusting layer and decreases the adhesion between the layers. Since steam is released to the outside via the gap, it does not rupture, and it can prevent contamination of the microwave oven by contents such as food, and also adjust the laminate strength In normal temperature (30 ° C) or less, in order to maintain strong adhesive strength between the base material layer and the inner layer, it is said that the bag will not be broken due to force majeure pressure or impact applied during normal transportation or storage. There is an effect.

The present invention will be described in detail with reference to the drawings.
FIG. 1 is a partially transparent main part plan view showing a first embodiment of a microwave packaging bag according to the present invention, FIG. 2 is an enlarged cross-sectional view schematically showing a cross section taken along line XX of FIG. FIG. 4 is a partially transparent perspective view showing a second embodiment of a packaging bag for a microwave oven according to the present invention, FIG. 4 is an exploded perspective view of FIG. 3, and FIG. 5 schematically shows a cross section taken along line YY of FIG. 6 is a partially omitted enlarged sectional view, FIG. 6 is a partially transparent plan view showing a third embodiment of a packaging bag for a microwave oven according to the present invention, FIG. 7 is an exploded perspective view of FIG. 6, and FIG. It is a figure corresponding to FIG. 7 which shows 4th Embodiment of the packaging bag for ranges, In the figure, 1,1 ', 1 "is a packaging bag for microwave ovens, 2 is a base material layer, 3 is a printing layer, 4 is Conductive heat generating layer, 5 is a laminate strength adjusting layer, 6 is an adhesive layer, 7 is an inner layer, 8 is a folded portion, 9 is a notch, 10 is a back-bonded thermal bonding portion, 20 is an end thermal bonding portion, 30 , 30 ', 30 "are lower thermal bonding portions, 40, 40' are side edge thermal bonding portions, 50, 50 'are upper thermal bonding portions, A, B, C are laminates, and b, b' are front walls. Members, c and c ′ are rear wall members, d and d ′ are gusset portion forming members, G is a gusset portion, and α is a laminate strength adjustment region.

  FIG. 1 is a partially transparent plan view showing a first embodiment of a microwave packaging bag according to the present invention, and FIG. 2 is an enlarged sectional view schematically showing a section taken along line XX of FIG. The microwave packaging bag 1 includes a base layer 2, a printed layer 3, a conductive heat generating layer 4, a laminate strength adjusting region α having a laminate strength adjusting layer 5, an adhesive layer 6, and an inner layer 7 made of a heat adhesive resin. The laminated body A is made with a pillow type packaging machine, and is attached to the back-bonded heat-bonding portion 10 and the ends of the back-bonded heat-bonding portion 10 at right angles. A pillow type packaging bag having a partial thermal bonding portion 20 (only one edge thermal bonding portion is shown), and the conductive heat generating layer 4 and the laminate strength adjusting layer 5 are bonded to the edge thermal bonding. Of the layered product A constituting the surface of the portion 20 opposite to the surface having the back-bonded thermal bonding portion 10 The edge from the inner edge of the edge thermal bonding portion 20 to the outer edge of the edge thermal bonding portion 20 is formed on a part of the edge thermal bonding portion 20 between the printing layer 3 and the adhesive layer 6. The conductive heat generating layer 4 is formed so as to cross the edge heat bonding portion 20 and substantially coincide with the laminate strength adjustment region α where the laminate strength adjustment layer 5 is formed.

  3 is a partially transparent perspective view showing a second embodiment of the microwave packaging bag according to the present invention, FIG. 4 is an exploded perspective view of FIG. 3, and FIG. 5 is a schematic cross-sectional view taken along line YY of FIG. 1 is a partially omitted enlarged cross-sectional view showing a microwave packaging bag 1 ′ having a base material layer 2, a printing layer 3, a conductive heating layer 4, and a laminate strength adjustment region α and an adhesive. A rectangular front wall member b made of a laminate B provided with a layer 6 and an inner layer 7 made of a heat-adhesive resin, an inner layer made of a base material layer 2, a printed layer 3, an adhesive layer 6, and a heat-adhesive resin 7 and the rear wall member c, which is longer than the front wall member b in the direction of the front wall member b, are stacked so that the inner layers 7 face each other so that the three edges coincide with each other. A rectangular body made of a laminate C including a base layer 2, a printing layer 3, an adhesive layer 6, and an inner layer 7 made of a heat-adhesive resin. The gusset portion forming member d is folded in a substantially V shape at the folding portion 8 so that the inner layer 7 is exposed, and the folding portion 8 is folded back and forth in the substantially V-shaped gusset portion forming member d. Three edge portions of the gusset portion forming member d excluding the folded portion 8 are connected to the edge portions of the stepped front and rear wall members b and c so as to be positioned between the wall members b and c. Are inserted so as to coincide with both end edges of the gusseted portion d, and the end edges of the gusset portion forming member d facing the fold portion 8 and the end edges in the direction perpendicular to the fold portion 8 are respectively connected to the lower thermal bonding portions 30, 30 ′. The lower thermal bonding portions 30, 30 ′ are joined by sealing the end edges facing the lower thermal bonding portions 30, 30 ′ with the upper thermal bonding portions 50. A packaging bag having a gusset portion G on the side, the conductive heat generating layer 4 and the laminating The lower thermal bonding portion is formed on a part of the lower thermal bonding portion 30 between the printed layer 3 and the adhesive layer 6 of the front wall member b made of the laminate B. Laminate strength adjustment region in which the conductive heat generating layer 4 is formed with the laminate strength adjustment layer 5 so as to traverse the lower thermal bond portion 30 from the inner side to the outer edge of the lower thermal bond portion 30 It is formed so as to substantially coincide with α. 3 and 4 show the conductive heat generating layer 4 and the laminate strength adjusting layer 5 provided in a part of the lower thermal bonding portion 30, but the entire region of the lower thermal bonding portion 30 is shown. May be provided in a band shape (see FIGS. 6 and 7) so as to reach the both-side end thermal bonding portions 40, 40 so as to cover the front wall member b, without being provided on the front wall member b. It may be provided on the gusset portion forming member d.

  6 is a partially transparent perspective view showing a third embodiment of the microwave packaging bag according to the present invention, FIG. 7 is an exploded perspective view of FIG. 6, and the microwave packaging bag 1 ″ is a base material. A laminate B (in FIG. 5) including a layer 2, a printed layer 3, a conductive heating layer 4, a laminate strength adjusting region α having a laminate strength adjusting layer 5, an adhesive layer 6, and an inner layer 7 made of a heat adhesive resin. The laminated body C (of FIG. 5) provided with a rectangular front wall member b ′ made of the same layer structure), a base material layer 2, a printed layer 3, an adhesive layer 6, and an inner layer 7 made of a heat-adhesive resin. The front wall member b ′ and the rear wall member c ′ having the same dimensions as each other) and the inner layers 7 of the front and rear wall members b ′ and c ′ are opposed to each other so that the four edges match each other. On the other hand, a laminate C (including a base material layer 2, a printing layer 3, an adhesive layer 6 and an inner layer 7 made of a thermoadhesive resin) The rectangular gusset portion forming member d ′ having the same structure as that of layer 5 is folded in a substantially V shape at the folding portion 8 so that the inner layer 7 is exposed, and is connected to the folding portion 8 in the folded state. A semicircular cutout 9 is provided in a substantially central portion of both end edges so as not to exceed the inner edges of both side end thermal bonding portions 40 ′ and 40 ′, and this gusset portion forming member d ′ is connected to the folded portion. 8 is positioned between the front and rear wall members b ′ and c ′, and three end edges of the gusset portion forming member d ′ excluding the folding portion 8 are three of the front and rear wall members b ′ and c ′. The two end edges in the direction orthogonal to the folded portion 8 are joined by side end thermal bonding portions 40 ′ and 40 ′, and the gusset portion forming member d ′ is provided. The edge opposite to the folding part 8 is connected to the inner edge of the both-side end thermal bonding parts 40 ′, 40 ′ and the folding part. The inner edges of the lower thermal bonding portions 30 ", 30" are connected to each other at a substantially arc-like shape, and the edge opposite to the lower thermal bonding portions 30 ", 30" is connected to the upper thermal bonding portion. 50 ′, a standing type packaging bag having a gusset portion G on the lower thermal bonding portion 30 ″, 30 ″ side, wherein the conductive heat generating layer 4 and the laminate strength adjusting layer 5 are At least a part of the lower thermal bonding portion 30 ″ between the printed layer 3 and the adhesive layer 6 of the front wall member b ′ made of the laminate B, inside the inner edge of the lower thermal bonding portion 30 ″. The conductive heat generating layer 4 substantially coincides with the laminate strength adjustment region α where the laminate strength adjustment layer 5 is formed so as to cross the lower heat bond portion 30 from the outer edge of the lower heat bond portion 30 ″ to the outer edge of the lower heat bond portion 30 ″. It is formed to do.

  The lower thermal bonding portion 30 ″ may be a belt-like thermal bonding portion, similar to the lower thermal bonding portions 30 and 30 ′ shown in FIG. 3. Also, in FIGS. The band strength of the laminate strength adjustment region α, which is partly located on the inner side of the inner edge of the lower thermal bonding portion 30 ″, is shown. As shown in FIGS. It may be partially provided in the central portion so that a part thereof is located inside the inner edge of the lower thermal bonding portion 30 ″. Further, the laminate strength adjusting region α may be provided in the gusset portion forming member d ′ as shown in FIG. 8 without being provided in the front wall member b ′. In this case, the front wall member b 'uses the laminate C, and the gusset part forming member d' uses the laminate B. Moreover, in the packaging bag of 2nd Embodiment, 3rd Embodiment, and 4th Embodiment shown to FIGS. 3-8, the said rear wall member c, the said gusset part formation member d, the said rear wall member c ', and the said gusset Although the portion forming member d ′ is shown as a separate member, the rear wall member c and the gusset portion forming member d, and the rear wall member c ′ and the gusset portion forming member d ′ are an integral member. It may be.

  By the way, in the first embodiment, the conductive heat generating layer 4 and the laminate strength adjusting layer 5 are provided at one location on the end thermal bonding portion 20, but may be provided at a plurality of locations, or the back side. It may be similarly provided in the pasting heat bonding part 10. In the third to fourth embodiments, the conductive heat generating layer 4 and the laminate strength adjusting layer 5 are provided on the lower thermal bonding portion 30 ″ of the gusset portion G. However, the microwave oven is maintained in a self-standing state. In consideration of the fact that cooking can be performed by heating, it is optimal to provide the upper thermal bonding portion 50'.In the first to fourth embodiments, the printing layer 3 is provided in the layer configuration, but printing has been described. Layer 3 is not an essential component.

  Next, various materials constituting microwave packaging bags (hereinafter sometimes referred to as packaging bags) 1, 1 ′, 1 ″ will be described. The base material layer 2 can be refrigerated or frozen in the distribution stage. It is a layer that serves as a base material for the packaging bag 1, 1 ′, 1 ″, such as being stored and cooked in a microwave oven at the time of use, and provided with a printed layer 3 if necessary. Synthetic resin films having excellent properties in terms of chemistry, chemistry, etc. can be used. For example, polyester resins, polyamide resins, polypropylene resins, polyacetal resins, etc. Etc., and any film such as an unstretched film or a stretched film stretched in a uniaxial or biaxial direction should be used. The thickness of the film may be a thickness that can be held to the minimum necessary for strength, rigidity, etc. as a base material, and may be determined in consideration of cost, etc. A stretched film stretched in the biaxial direction is preferred.

  The base material layer 2 may be provided with required physical properties, for example, gas barrier properties such as oxygen and water vapor, and the above-mentioned synthetic resin film coated with polyvinylidene chloride, What formed the vapor deposition layer of inorganic substances, such as a silicon oxide, aluminum oxide, an indium oxide, a tin oxide, a zirconium oxide, may be used.

  The base material layer 2 may be composed only of the above-described synthetic resin film or a synthetic resin film imparted with a gas barrier property, but mechanical toughness, flex resistance, puncture resistance, When a higher function is required in terms of impact resistance, cold resistance, heat resistance, chemical resistance, etc., two or more kinds of films may be appropriately selected from the above-described films and laminated.

  The inner layer 7 may be appropriately selected and used depending on the physical properties required for the packaging bag 1, 1 ′, 1 ″. For example, low density polyethylene, medium density polyethylene, high density polyethylene, linear (linear) ) Low density polyethylene, polypropylene, ethylene-α olefin copolymer, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid copolymer, ethylene-methyl acrylate copolymer, What was shape | molded with resin which consists of 1 type or more of resin, such as ethylene-methacrylic acid copolymer, can be used, and it may be a single | mono layer or a multilayer.

  Next, the laminate strength adjusting layer 5 will be described. The laminate strength adjusting layer 5 has a predetermined strength at an environmental temperature of room temperature or lower, but has a property that the strength decreases at a high environmental temperature. In addition, room temperature means 30 degreeC.

  The ambient temperature below a room temperature having a predetermined strength usually means the environmental temperature in the packaging process for packaging the contents, the environmental temperature in the process for refrigeration or freezing the packaging bag in which the contents are packaged, refrigeration or freezing. It is the environmental temperature at the distribution stage where it is transported and stored in a state where it has been transported. Therefore, the laminate strength adjusting layer 5 is maintained at a predetermined strength under the environmental temperature described above. On the other hand, the high temperature environment where the predetermined strength is reduced is a temperature applied when the packaging bag in which the contents are hermetically sealed is heated and cooked in a microwave oven. Under such a high environmental temperature, the laminate strength adjusting layer is used. The strength of 5 will be reduced.

  Examples of the laminate strength adjusting layer 5 having such properties include materials having a melting point of 60 to 90 ° C., such as ethylene-vinyl acetate copolymer resin, polyamide-nitrified cotton-based resin, polyamide-nitrified cotton-polyethylene wax. Examples thereof include resins mainly composed of any one of the resin types. By using a resin having a melting point of 60 to 90 ° C., cohesive peeling can easily occur between the laminate strength adjusting layers 5 when cooking with a microwave oven.

  For example, the laminate strength adjusting layer 5 needs to be formed in a pattern in register with the printing layer 3, and is suitably formed simultaneously with the printing layer 3 by a printing method such as a gravure printing method. The film thickness of the laminate strength adjusting layer 5 is not less than 1 μm and not more than 5 μm. When the film thickness is less than 1 μm, cohesive peeling does not easily occur between the laminate strength adjusting layers 5 when cooked in a microwave oven, and when the film thickness exceeds 5 μm, the packaging bags 1, 1 ′, 1 ″ Before being done, it is normally supplied in a roll state and is formed into a bag shape by a bag making machine. However, in the roll state, the portion provided with the laminate strength adjusting layer 5 is raised, and as a result, the portion is stretched to make a bag. Defects may occur, resulting in a decrease in yield, and defects such as the appearance of a finished bag having a poor appearance.

  The laminate strength adjustment region α having the laminate strength adjustment layer 5 has a laminate strength (laminate strength between the base material layer 2 and the inner layer 7) of 0.3 N / 15 mm width or more and 5.0 N / in an ambient temperature of room temperature or less. 15 mm width or less, 2.0 N / 15 mm width or less at high environmental temperature (under 90 ° C. or higher environmental temperature), and laminate strength in regions other than the laminate strength adjustment region α (base layer 2 and The laminate strength between the inner layers 7 is not less than 3.0 N / 15 mm width at an ambient temperature of room temperature or lower, and not less than 0.5 N / 15 mm width at a high ambient temperature (under 90 ° C. ambient temperature). Incidentally, the heat seal strength of the laminate strength adjustment region α having the laminate strength adjustment layer 5 when the linear (linear) low density polyethylene film (thickness of 30 μm) is used as the inner layer 7 is an environment of room temperature or less. It is 20.0 N / 15 mm width or more under temperature, 15.0 N / 15 mm width or less under high environmental temperature (under 90 ° C. environmental temperature), and heat in a region other than the laminate strength adjustment region α. The seal strength is 40.0 N / 15 mm width or more at ambient temperature below room temperature, 20.0 N / 15 mm width or more at high environment temperature (under 90 ° C. environment temperature), and high ambient temperature ( The laminate strength having the laminate strength adjustment layer 5 having a heat seal strength other than the laminate strength adjustment region α at an environmental temperature of 90 ° C. or higher) It is important to design such that the 5.0 N / 15 mm width or more as compared with the heat seal strength integer area alpha.

  By configuring the laminate strength adjustment region α and the strength other than this region as described above, when the cooking is performed in a microwave oven, the internal pressure increases due to water vapor generated from the contents, and the laminate strength adjustment layer 5 is heated. Causes the cohesive peeling to lower the laminate strength, and in this part, the internal pressure must be maintained by the tensile strength of the inner layer 7 itself, and the region other than the laminate strength adjustment region α has the laminate strength adjustment layer 5. Since the laminate strength is stronger than the laminate strength adjustment region α, cracks are likely to occur at the boundary between the laminate strength adjustment region α having the laminate strength adjustment layer 5 and other regions, and finally it can withstand the internal pressure. The inner layer 7 is cut at the boundary portion without causing aggregation and peeling due to the internal pressure from the cut portion. Peeling progresses to the laminate strength adjusting layer 5, and, for example, in the case of the first embodiment shown in FIG. 1, when the peeling reaches the outer edge of the edge thermal bonding portion 20, the internal pressure is released to the outside. Therefore, unlike the explosive release (bag rupture), the contents do not scatter and the microwave oven is not contaminated with the contents. However, for example, in the case of a high-power microwave oven such as a commercial microwave oven, the timing at which the internal pressure is increased by water vapor or the like, and the timing at which the laminate strength adjusting layer 5 is softened by heat and the laminate strength is decreased. If it is extreme, it may burst and contaminate the contents of the microwave oven with the contents.

  Therefore, a component that generates heat by microwaves, ie, the conductive heat generating layer 4 is provided so that at least a part thereof is applied to the laminate strength adjusting region α formed of the laminate strength adjusting layer 5 (in the embodiment, the conductive heat generating layer 4 is provided so as to substantially coincide with the laminate strength adjustment region α composed of the laminate strength adjustment layer 5, but only a part of the laminate strength adjustment region α may be applied.) The laminate strength adjusting layer 5 was more reliably softened by heat to make it easy to cause cohesive peeling.

The conductive heat generating layer 4 is not particularly limited as long as it is a substance that absorbs microwaves and generates heat, but considering that it becomes an ink, carbon black, silver, aluminum, ITO (indium tin oxide) and the like are suitable, and carbon black is preferred because it can be easily used as an ink for gravure printing. The surface resistivity is preferably 10 Ω / □ or more and 10 ⁷ Ω / □ or less. The reason for this is less than 10 [Omega / □ heating value is reduced to the microwave is reflected, it is because the 10 ⁷ Ω / □ ultra heating value resistor is too large is reduced. The conductive heat generating layer 4 needs to be formed in a pattern, for example, in register with the printing layer 3 in the same manner as the laminate strength adjusting layer 5, and the printing layer 3 can be formed by a printing method such as a gravure printing method. It is appropriate to form them at the same time.

  The method for laminating at least the base material layer 2 and the inner layer 7 of the packaging bag 1, 1 ′, 1 ″ of the present invention is, for example, a urethane anchor coat composed of a polyol component and an isocyanate component as the adhesive layer 6. The inner layer 7 may be laminated by a T-die extrusion method using an adhesive or a urethane adhesive, or the inner layer 7 may be laminated in a sheet shape by a sandwich lamination method, or by a dry lamination method. The sheet-like inner layer 7 may be laminated, and an easy adhesion treatment such as a corona discharge treatment may be performed on a necessary surface by a lamination method.

  Moreover, the packaging bag for microwave ovens of this invention is not restricted to the 1st-4th embodiment shown to FIGS. 1-8, For example, a three-side seal type, a four-side seal type, a gusset type etc. All packaging bags within the scope not departing from the spirit are included in the present invention.

  Next, the present invention will be described in more detail with reference to the following examples.

A solid pattern printing layer is formed on the corona discharge treated surface of a 12 μm thick biaxially stretched polyethylene terephthalate film (hereinafter referred to as PET film) by a gravure printing method using a one-component curable urethane-based white ink. After drying a rectangular conductive heating layer of 40 mm (MD direction of PET film) × 35 mm (TD direction of PET film) by gravure printing using the gravure ink blended as shown in Table 1 on the pattern print layer surface, the thickness becomes 2 μm. Next, the laminate strength adjusting layer of the same size is dried with a printing ink made of polyamide-nitrified cotton-based resin (melting point: 83 ° C.) and the thickness of the laminate becomes 3 μm after drying. After forming by the gravure printing method, the two-component curable urethane adhesive (polyol component and the A two-component curable resin comprising a cyanate component) is applied and dried so as to be 3.5 g / m 2 after drying, and a low-density polyethylene film (hereinafter referred to as LDPE film) having a thickness of 30 μm is dry-laminated. Thus, a laminate for use in the present invention was prepared. The laminated body accommodated one chilled meat bun (80 g) having an outer dimension of 120 mm (TD direction) × 160 mm (MD direction) and a heat seal width of 10 mm each for the edge thermal bonding portion and the back bonding thermal bonding portion. Twenty pillow-type packaging bags according to the first embodiment shown in FIG. 1 were produced.

[Comparative Example 1]
Twenty pillow-type packaging bags were produced in the same manner as in Example 1 except that the conductive heat generating layer was not provided.

  Each of the 20 pillow-type packaging bags prepared in Example 1 and Comparative Example 1 was cooked with a microwave oven (1600 W), and the state in which the internal pressure escaped was visually confirmed. Table 2 shows the evaluation results. It was shown to.

  As is apparent from Table 2, the packaging bag for microwave oven of the present invention has the effect that the conductive heat generating layer and the laminate strength adjusting layer are provided between the base material layer and the inner layer, so that the bag does not rupture, The internal pressure could be released smoothly, and the contents of the microwave oven were not contaminated with the contents.

It is a partially transparent principal part top view which shows 1st Embodiment of the packaging bag for microwave ovens concerning this invention. It is an expanded sectional view which shows the section of the XX line of Drawing 1 diagrammatically. It is a partially transparent perspective view which shows 2nd Embodiment of the packaging bag for microwave ovens concerning this invention. FIG. 4 is an exploded perspective view of FIG. 3. FIG. 4 is a partially omitted enlarged cross-sectional view schematically showing a cross section taken along line YY in FIG. 3. It is a partially transparent top view which shows 3rd Embodiment of the packaging bag for microwave ovens concerning this invention. FIG. 7 is an exploded perspective view of FIG. 6. It is a figure corresponding to FIG. 7 which shows 4th Embodiment of the packaging bag for microwave ovens concerning this invention.

Explanation of symbols

1, 1 ', 1 "microwave packaging bag 2 base material layer 3 printed layer 4 conductive heat generating layer 5 laminate strength adjusting layer 6 adhesive layer 7 inner layer 8 folded part 9 notch 10 back-attached thermal adhesive part 20 end heat Bonding part 30, 30 ', 30 "Lower thermal bonding part 40, 40' Side edge thermal bonding part 50, 50 'Upper thermal bonding part A, B, C Laminate b, b' Front wall member c, c 'After Wall member d, d 'Gusset part forming member G Gusset part α Laminate strength adjustment region

Claims (5)

A packaging bag for a microwave oven in which a laminate including at least a base material layer and an inner layer made of a heat-adhesive resin is formed and sealed with an edge heat-bonding portion, and constitutes the edge heat-bonding portion A laminate strength adjustment region comprising a laminate strength adjustment layer that crosses the edge thermal bonding portion from the inside to the outside of the packaging bag between the base material layer and the inner layer of the laminate on the side of A conductive heating layer is formed between the base material layer and the laminate strength adjusting layer so as to cover at least a part of the laminate strength adjusting region, thereby forming the laminate strength adjusting layer and the laminate strength adjusting layer. A packaging bag for a microwave oven, wherein the conductive heat generating layer is sandwiched between the base material layer and the inner layer . A packaging bag for a microwave oven in which a laminate including at least a base material layer and an inner layer made of a heat-adhesive resin is formed and sealed with an edge heat-bonding portion, and constitutes the edge heat-bonding portion A laminate strength adjustment region comprising a laminate strength adjustment layer that crosses the edge thermal bonding portion from the inside to the outside of the packaging bag between the base material layer and the inner layer of the laminate on the side of A conductive heating layer is formed between the base material layer and the laminate strength adjusting layer so as to cover at least a part of the laminate strength adjusting region, thereby forming the laminate strength adjusting layer and the laminate strength adjusting layer. The conductive heat generating layer is sandwiched between the base material layer and the inner layer, and the conductive heat generating layer is formed by printing with an ink containing at least carbon black and has a surface resistivity of 10Ω / □ or less. 10 ⁷ Ω / □ microwave packaging bag, characterized in that at most. 3. The electron according to claim 1, wherein the conductive heat generating layer is formed so as to cross the edge thermal bonding portion from the inner side to the outer side of the packaging bag. Packaging bag for range . The packaging bag for a microwave oven according to claim 3, wherein the conductive heat generating layer is formed so as to substantially coincide with the laminate strength adjustment region . The laminate strength adjusting layer is mainly composed of any one of ethylene-vinyl acetate copolymer resin, polyamide-nitrified cotton-based resin, and polyamide-nitrified cotton-polyethylene wax-based resin having a melting point of 60 to 90 ° C. It consists of resin, The packaging bag for microwave ovens in any one of Claims 1-4 characterized by the above-mentioned .

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