WO2019111733A1

WO2019111733A1 - Packaging bag for heating

Info

Publication number: WO2019111733A1
Application number: PCT/JP2018/043236
Authority: WO
Inventors: 勝弘本郷; 三浦　崇; 史絵松永
Original assignee: 東洋製罐株式会社
Priority date: 2017-12-07
Filing date: 2018-11-22
Publication date: 2019-06-13

Abstract

The present invention relates to a packaging bag that is for heating and comprises a multilayer film including at least a welding layer and a base layer formed from a polyester resin. During tensile testing (ambient temperature 200°C, sample width 10 mm, distance between chucks 20 mm, tensile speed 1 mm/min) of a resin film that constitutes the outermost layer of the multilayer film, at the point when a sample had been extended 10 mm, the load per unit of thickness of the sample was 0.25 N/μm or below, and therefore even if internal pressure is exerted on the packaging bag and the packaging bag expands, such as when heated in a microwave, not only are holes prevented from forming in the packaging bag, any damage to the outside surface is also prevented from occurring.

Description

Packaging bag for heating

The present invention relates to a heating packaging bag, and more particularly to a heating packaging bag in which occurrence of damage such as a crack in an outermost layer is effectively suppressed even when being subjected to microwave oven heating.

Conventionally, various packaging bags have been proposed in which contents such as food are filled and sealed in a packaging bag and microwave heating is performed when eating. Such packaged bagged foods are heated in an unopened state, and thus the internal pressure is increased by heating and also affected by the heat from the contents, which may cause damage to the packaging bag. For example, in a container compatible with microwave heating, even if the container is provided with a mechanism for releasing the internal pressure in the packaging bag, the packaging bag is thermally damaged (the film is melted by the heat due to the properties of the content and the heat and internal pressure of the content). And there was a problem of causing holes.

In order to solve such a problem, it has been proposed to use a highly heat resistant film such as a polybutylene terephthalate film as a base material layer constituting a packaging bag for microwave heating (Patent Document 1).
However, even when such a highly heat-resistant film is used, heat damage may occur on the inner surface of the packaging bag if the high viscosity, high oil content is stored or heated by a high output microwave oven. there were.
Also, regardless of the type of contents, packaging bags for microwave oven heating that can also be compatible with high output microwave ovens have been proposed, and polyester films from the outer surface, polyester films having a barrier layer, tearable polyester films, heat A packaging bag for microwave oven heating, which is composed of a laminated film made of a sealing polyolefin film, has also been proposed (Patent Document 2).

JP, 2006-143223, A JP, 2014-151945, A

Although the above-mentioned packaging bag for microwave heating has excellent heat resistance and damage from the inside of the packaging bag is effectively prevented, it is caused by the expansion of the packaging bag during microwave heating. However, the outermost layer of the packaging bag did not reach the perforation of the packaging bag, and damage such as a crack could occur. Such damage is not preferable because even if it is not a problem as the function of the packaging bag, the consumer may be reminded of the rupture of the packaging bag.

Therefore, it is an object of the present invention to provide a heating package which does not cause any damage on the outer surface, of course, even if the packaging bag is expanded due to an internal pressure being applied to the packaging bag as in heating by a microwave oven or the like. It is to provide a bag.

According to the present invention, there is provided a heating packaging bag comprising a multilayer film comprising at least a substrate layer comprising a polyester resin and a welding layer, wherein the tensile test of the resin film constituting the outermost layer in the multilayer film At an atmosphere temperature of 200 ° C., a sample width of 10 mm, a chuck distance of 20 mm, and a tensile speed of 1 mm / min), the load per unit thickness of the sample is 0.25 N / μm or less when the elongation of the sample becomes 10 mm. A heating packaging bag characterized by the above is provided.

In the heating packaging bag of the present invention,
1. The outermost layer is any of a polyethylene terephthalate film, a polybutylene terephthalate film, a film composed of a blend of polyethylene terephthalate and polybutylene terephthalate, a coextrusion film of polyethylene terephthalate and polybutylene terephthalate, or a nylon film.
2. The multilayer film is a multilayer film having a layer structure of a polyethylene terephthalate layer / welding layer having a polybutylene terephthalate layer / vapor deposited layer or coating layer in order from the outside, or a polyethylene terephthalate layer / polybutylene having a vapor deposited layer or coating layer A multilayer film having a layer configuration of a terephthalate layer / welding layer, or a multilayer film having a layer configuration of a co-extrusion film of polyethylene terephthalate and polybutylene terephthalate having a deposited layer or a coating layer / welding layer,
3. The packaging bag is a packaging bag for microwave heating, and the moisture content of the multilayer film is 1.0% or less when the packaging bag is filled with the contents.
4. The packaging bag is a packaging bag for microwave heating, and the moisture content of the multilayer film is 1.5% or less when the packaging bag is filled with the content, and the multilayer film is the outermost layer and the intermediate layer And each of the outermost layer and the intermediate layer comprises at least one layer of polyester resin, and the intermediate layer further comprises nylon.
5. The packaging bag includes a steam venting mechanism including a steam venting portion, a non-bonded portion formed around the steam drained portion, and a steam venting seal portion formed around the non-bonded portion.
Is preferred.

Commercially available polyester films used for packaging bags for heating, for example, films commercially available as polyethylene terephthalate (PET) films, have various values of elongation value in the above-mentioned tensile test. The inventors of the present invention have used a film having a load of 0.25 N / μm or less when the elongation in the above-described tensile test is 10 mm as a resin constituting the outermost layer of a laminate, thereby achieving microwave heating etc. It has been found that the occurrence of cracks in the outermost layer can be effectively prevented even when the heating packaging bag is expanded due to an increase in internal pressure.

Such effects of the present invention are also apparent from the results of the examples described later.
That is, in the pouch (Examples 1 to 10) formed using the laminated film having the film having the value of the load described above of 0.25 N / μm or less as the outermost layer, the contents are filled and then microwave heating is performed. Also, while no damage was found on the outer surface as well as perforation of the packaging bag, a film having a load value larger than 0.25 N / μm was used as the film constituting the outermost layer. In the pouch using the laminated film having the same layer configuration as that of the example, when the microwave oven heating was performed after filling the contents, the packaging bag did not have perforations, but the outer surface had cracks. (Comparative Examples 1 to 4).
Further, as is clear from the comparison between Example 1 and Comparative Example 1, even when a PET film is used as the outermost layer, lamination using a PET film having a load value of 0.25 N / μm or less as described above The pouch made of a film does not cause any damage on the outer surface, whereas the pouch made of a laminated film using a PET film having a load value larger than 0.25 N / μm has an outer surface. There was a crack in the

It is a figure which shows an example of the laminated constitution of the multilayer film used for the packaging bag for heating of this invention. It is a figure which shows an example of the packaging bag for heating of this invention. FIG. 2 is a cross-sectional view taken along line XX in FIG.

(Multilayer film)
The multilayer film constituting the heating packaging bag of the present invention comprises at least a substrate layer made of polyester resin and a welding layer, and the resin film constituting the outermost layer of the multilayer film has an ambient temperature of 200 ° C., a sample When a tensile test is conducted at a speed of 1 mm / min with a width of 10 mm and a distance between chucks of 20 mm, a value obtained by dividing the load at the point when the elongation of the sample becomes 10 mm by the thickness of the sample (hereinafter, this value is simply It is an important feature that “the load” is sometimes 0.25 N / μm or less, particularly in the range of 0.1 N / μm to 0.2 N / μm. When the heating packaging bag containing the contents is subjected to microwave oven heating, the properties of the contents (metal salt, oil and high viscosity contents, such as retort curry, salmon ingredients, soups, etc. In some cases, the surface temperature of the packaging bag may reach 200 ° C. locally. From this, it is important to set the ambient temperature because it is necessary to make the packaging bag of a property resistant to damage even when the temperature is set to 200 ° C. similar to the surface temperature of the packaging bag.
The multilayer film constituting the heating packaging bag of the present invention has at least a base material layer and a welding layer, and when the base material layer is the outermost layer (when it has a two-layer structure without an intermediate layer) The resin film of the outermost layer which comprises a base material layer needs to satisfy the value of the said load.
In the case where the base material layer is a multi-layered base material layer including two kinds of the outermost layer and the intermediate layer, at least one of the base material layers may be made of polyester resin. In this case, the outermost layer It is necessary that the resin film that constitutes the above satisfies the above load value.

In the present invention, as the film constituting the outermost layer, various thermoplastic resins can be used as long as the load is in the above range. Preferably, it is formed of polyethylene terephthalate, polybutylene terephthalate, a blend of polyethylene terephthalate and polybutylene terephthalate, a coextruded film of polyethylene terephthalate and polybutylene terephthalate, or nylon. As described above, the properties of the film also differ depending on the presence or absence of a modifier component such as a copolymerization component among the polyethylene terephthalate, or the position of the end portion or central portion of the stretched film, and the value of the load varies. It is important to select a polyethylene terephthalate having a load in the above range.
The resin film constituting the outermost layer may or may not be stretched as long as the load is in the above range, but is preferably biaxially stretched from the viewpoint of mechanical strength and the like.
Furthermore, as long as the load is in the above range, a barrier film having a vapor deposition layer, a coating layer, etc. formed on one side of the resin film can be used as the outermost layer. In this case, the resin film side is the outermost layer. use.
The thickness of the film constituting the outermost layer is in the range of 5 μm to 50 μm, particularly 10 μm to 30 μm, in any of the case where the substrate layer is only the outermost layer, or when the substrate layer is provided on the outermost layer and the intermediate layer. Is preferred.

[Base layer of outermost layer and intermediate layer]
Various thermoplastic resins can be used as resin which can be used for the base material layer which constitutes a multilayer film in the packaging bag of the present invention. It is preferable to use any of polyester resin, polycarbonate resin, polyetheretherketone resin and nylon, and in particular, polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate or a blend of polyethylene terephthalate and polybutylene terephthalate, polyethylene terephthalate and the like It is preferable that the film is made of either a co-extruded film of polybutylene terephthalate, or a copolymer of ethylene terephthalate and ethylene naphthalate.
The film constituting the substrate layer is preferably uniaxially or biaxially stretched, and in particular, a biaxially stretched film excellent in mechanical strength, crack resistance and heat resistance can be suitably used.
Moreover, the base film may use the above-mentioned film alone, or may be a multi-layer base layer (the outermost layer and the intermediate layer) according to a laminating method in which a plurality of different films are described later.
The thickness of the substrate layer is preferably in the range of 5 μm to 50 μm, particularly 10 μm to 30 μm. If the thickness of the substrate layer is thinner than the above range, mechanical strength and crack resistance will be inferior as compared to the above range, while if it is thicker than the above range, tearing will occur compared to the above range. It becomes inferior to sex and economy.

[Welding layer]
In the packaging bag of the present invention, a heat sealable resin which has been conventionally used as a welding layer (heat seal layer) of a heating packaging bag can be used as a welding layer constituting a multilayer film.
Specifically, low-, medium- or high-density polyethylene, linear low density polyethylene, isotactic polypropylene, syndiotactic polypropylene, linear low density polyethylene, ethylene-propylene copolymer, polybutene-1, Poly 4-methyl-1-pentene, ethylene-butene-1 copolymer, propylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, ionic crosslinked olefin co-polymer Polymers (ionomers), ethylene-acrylic acid ester copolymers, etc. may be mentioned. These can be used alone or in the form of two or more blends.
In particular, a propylene-based polymer is suitable from the viewpoint of heat resistance, and homopolypropylene, and a random copolymer or block copolymer mainly composed of propylene can be used.
Further, from the viewpoint of weldability, it is particularly desirable that the film constituting the weld layer be non-stretched.
The thickness of the welding layer is preferably in the range of 30 μm to 150 μm, particularly 50 μm to 100 μm. When the thickness of the welding layer is thinner than the above range, the drop strength and the heat sealability become inferior as compared to the above range, while when it is thicker than the above range, the tearing occurs compared to the above range. It becomes inferior to sex and economy.

[Others]
The multilayer film constituting the package of the present invention comprises at least a substrate layer made of polyester resin and a welding layer, and the above-mentioned resin film having a load of 0.25 N / μm or less as the outermost layer is used. In addition to the outermost layer, the base material layer (intermediate layer) and the welding layer, it may have other layers conventionally used for a heating packaging bag, but is not limited thereto, but a barrier layer, an easily tearable layer In the present invention, it is particularly preferable to have a barrier layer.

[Barrier layer]
The barrier layer can be formed by chemical vapor deposition (CVD), vacuum evaporation, sputtering, ion plating, etc., using an inorganic material such as silicon oxide, a ceramic such as alumina, carbon, etc. A vapor-deposited layer formed by vapor deposition, or a coating layer comprising a barrier resin coating agent comprising a polycarboxylic acid-based polymer, vinylidene chloride, or a compound having an ethylene vinyl alcohol copolymer or a metalloxane bond, etc. In particular, vapor deposition layers of silica or alumina are preferably used.
The resin film used for the barrier layer is preferably biaxially stretched.
As described above, the barrier layer may be the outermost layer as long as the value of the load satisfies the above range, or may be disposed between the base material layer and the welding layer.
The thickness of the resin film on which the vapor deposition layer or the coating layer is formed is preferably in the range of 5 μm to 25 μm. When the thickness of the resin film is smaller than the above range, mechanical strength and crack resistance are inferior as compared to the above range, while when it is thicker than the above range, the tearability is higher than that in the above range. And become less economical.

[Easy tearable layer]
The easily tearable layer improves the tearability of the packaging bag by causing the easily tearable layer to follow the welded layer by being adjacent to the less tearable welded layer.
The film constituting the easily tearable layer is not limited to this, but is a film made of a blend of polybutylene terephthalate containing polytetramethylene glycol units and polyethylene terephthalate, or made of polyethylene terephthalate and a polyester elastomer, and polyethylene A film obtained by biaxially stretching a film made of a blend of polyester elastomer dispersed in terephthalate, etc. can be mentioned. Alternatively, a polyester film may be processed by a laser or the like to give a tear-resistant film.
In addition, when the film which comprises an easily tearable layer satisfy | fills the said load, this easily tearable film can also be used as outermost layer.
The thickness of the easily tearable layer is preferably in the range of 5 to 30 μm. When the thickness of the resin film is smaller than the above range, mechanical strength and crack resistance are inferior as compared to the above range, while when it is thicker than the above range, the tearability and the tearability are higher than those in the above range. It becomes less economical.

[Layer structure]
As described above, the multilayer film used in the present invention can adopt a conventionally known layer configuration as long as the outermost layer is made of a resin film having a load of 0.25 N / μm or less, and at least a base layer made of polyester resin While having a welding layer, other layers, such as a barrier layer and an easily tearable layer, can be formed.
FIG. 1 shows an example of a multilayer film used in the packaging bag of the present invention, and the multilayer film generally indicated by 1 is an outermost layer (base layer) 2 and an intermediate layer (barrier layer) in order from the outside. 3 consists of a welding layer 4 and an adhesive layer 5 is provided between each layer.
In the embodiment shown in FIG. 1, the intermediate layer (barrier layer) 3 is a barrier layer 3 comprising a polyester resin layer 3b having a vapor deposition layer or a coating layer 3a, and this vapor deposition layer or coating layer 3a is the outermost layer substrate layer Those having a multilayer structure located on two sides can be suitably used.
In addition to the specific example shown in FIG. 1, as the multilayer film used in the present invention, a multilayer film having a two-layer structure of outermost layer (base material layer) / welding layer in order from the outside, outermost layer (base material layer) · Multilayer film having a layer configuration of barrier layer) / intermediate layer (base layer) / welding layer, multilayer film having a layer configuration of outermost layer (base layer) / barrier layer / easy tearable layer / welding layer, It is also possible to use a multilayer film having the layer configuration of outer layer (base layer) / intermediate layer (base layer) / barrier layer / easy tearable layer / welding layer, and the like. In any multilayer film configuration, any layer other than the welding layer may be a base material layer made of polyester resin.

The multilayer film used in the present invention can be laminated by a conventionally known laminating method such as dry laminating method, sandwich laminating method, extrusion laminating method.
For example, each film such as, but not limited to, the outermost layer, the base material layer, the welding layer, and the barrier layer can be prepared and laminated by a dry lamination method.
Further, polybutylene terephthalate constituting the outermost layer (substrate layer) is extrusion laminated on the vapor deposition layer or coating layer side of the film constituting the barrier layer having the vapor deposition layer or the coating layer to obtain a barrier layer and a substrate layer A multilayer film can be produced by producing a laminate composed of layers, and extruding and laminating polypropylene, which constitutes a deposition layer on the surface of a vapor deposition layer or a coating layer, through an adhesive resin.
Adhesives that can be used for the multilayer film used in the present invention include conventionally known polyether polyurethane-based or polyester polyurethane-based urethane-based adhesives, epoxy-based adhesives, or acid-modified thermoplastics such as maleic anhydride-modified polypropylene or the like. Although a resin adhesive etc. can be mentioned, it is suitable to use a urethane type adhesive from a viewpoint of retort resistance.
As a specific layer constitution of the multilayer film used in the present invention, a multilayer film having a layer constitution of a polyethylene terephthalate layer / welding layer having a polybutylene terephthalate layer / vapor deposited layer or a coating layer sequentially from the outside, or a vapor deposited layer or coating Multilayer film having a layer structure of polyethylene terephthalate layer / polybutylene terephthalate layer / welding layer having a layer, or multilayer film having a layer structure of co-extrusion film of polyethylene terephthalate and polybutylene terephthalate having a vapor deposited layer or a coating layer / welding layer It is preferable to use a layer structure of film.

(Packaging bag)
The heating packaging bag of the present invention is formed by welding so that the welding layers of the above-mentioned multilayer film face each other and welding the edges.
When the heating packaging bag of the present invention is compatible with microwave heating, it is preferable to have a steam removing mechanism capable of automatically opening during microwave heating and releasing steam.
In the packaging bag for microwave heating, it is particularly preferable that the moisture content as the multilayer film in the state in which the content is filled in the packaging bag is 1.5% or less, particularly 1.0% or less. Heat damage (hole leakage) in microwave heating is caused by heat from the contents and high pressure acting on the packaging bag by the internal pressure being placed in a state of being excessively high while the multilayer film is in a state of moisture absorption. Is considered to occur. That is, at the time of microwave oven heating, it is considered that thermal damage may occur due to the state in which the multilayer film absorbs moisture and the properties of the contents (such as the amount of water). For this reason, the heat resistance of the entire multilayer film is maintained by setting the moisture content as the multilayer film to 1.5% or less, particularly 1.0% or less in a state where the contents are filled in the packaging bag, and the steam removal It is effectively prevented that the heat resistance is impaired even in the state where the internal pressure is high, in combination with the presence of the holes. In addition, the state in which the contents are filled means the state commercially available as a product. Specifically, after filling the contents with aseptic filling or hot pack filling, the contents are filled and then boiled or retort, etc. After performing heat sterilization of, etc., the state in any timing is represented.

Moreover, when using nylon which is a base material with a high moisture content as an intermediate | middle layer of the multilayer film mentioned above, when the interlayer is made into nylon of a single layer, the moisture content as a multilayer film exceeds 1.5%, and heat resistance Is lost (comparative example 2). For this reason, when nylon is provided in the intermediate layer, a barrier layer in which a deposited layer or a coating layer is disposed on the welding layer side of nylon, and the moisture content as a multilayer film is 1.0% or less (Example 1), Water content is used as a multilayer film in which the intermediate layer is a laminate of polyester resin and nylon, and the content is filled in the packaging bag, using a polyester resin with a low water content as the substrate layer for each of the outermost layer and the intermediate layer. It is preferable to reduce the rate to 1.5% or less (Examples 11 to 14). With such a layer structure, the heat resistance of the entire multilayer film is maintained, and combined with the presence of the vapor vent, the heat resistance is effectively prevented from being impaired even in the state where the internal pressure is high. The polyester resin may be provided in at least one layer in each of the intermediate layer and the outermost layer.

FIG. 2 is a plan view of an example of the packaging bag for microwave oven heating of the present invention.
A packaging bag, generally designated 10, is formed by laminating the multilayer film 1 in two with the welding layer inside and welding the two sides and the top edge, so that 4 of the packaging bag 10 The side is sealed by the bottom portion 11, the

side seal portions

12 a and 12 b, and the top seal portion 13 to form the storage portion 14.
In this embodiment, a vapor removal mechanism 15 is formed at the upper left corner of the package 1. As apparent from FIG. 3 which is a cross-sectional view taken along line XX in FIG. 2 and FIG. 2 of the steam venting mechanism 15, when the internal pressure rises, the overlapping

multilayer films

1a and 1b can be retreated and peeled off. The surface of the non-adhered portion 21 with the vapor-released seal portion 20 adhered with adhesive strength, the

multi-layered films

1a and 1b located on the inside of the vapor-extracted seal portion 20 and in an overlapping state It comprises a steam vent 22 formed on the side multilayer film 1a.

In the specific example shown in the figure, the steam venting portion 22 penetrates the

multilayer films

1a and 1b on the surface side of the figure, and the direction of the position and corner portion 16 where the apex of the arc faces the center point of the packaging bag 10 It is formed as an elliptical hole 22a having an arc-like width (longest) width. When the internal pressure rises and the steam flows from the center to the end of the packaging bag, the packaging bag expands so that the

multilayer films

1a and 1b are separated from each other, so that The adhesion recedes and peels from the near part, and the steam flows into the non-adhesion part 21. In this aspect, the apex of the arc configuring the vapor removal part 22 is an arc shape facing the center point of the packaging bag 10 Then, as the steam starts to hit from the top of the arc of the steam vent 22 and the steam flows from the center to the periphery of the package 1, the arc of the steam vent 22 is expanded to the left and right to By widening the width, steam can be efficiently released from the steam removal portion 22 to the outside.
It is preferable that such an elliptical hole has a width of 3 to 20 mm in its longest width. In addition, it is preferable that the arc-like width (longest width) of the elliptical hole is an arc having a curvature radius of 2 mm to 100 mm with respect to a chord having a width of 3 mm to 20 mm.

[Form of package]
In the heating packaging bag of the present invention, the form of the packaging body is not limited to the above-described three-way seal aspect, but a four-way sealing packaging bag formed by laminating two multilayer films and sealing four sides, a gusset packaging bag, It can be formed into various forms such as a standing type packaging bag, a pillow type packaging bag and the like.

[Steam removal mechanism]
In the heating packaging bag of the present invention, the vapor removal mechanism formed to be compatible with microwave oven heating is not limited to the above-described embodiment as long as it can be automatically opened during microwave oven heating.
The position of the vapor removal mechanism is preferably formed in the vicinity of the peripheral seal portion of the packaging bag from the viewpoint of releasing the vapor in the packaging bag by microwave heating and preventing leakage of the contents.
Specifically, although depending on the size of the packaging bag, as disclosed in Japanese Patent Application Laid-Open No. 2002-249176, the initial breaking point of the steam releasing seal portion is set to the two short sides of the packaging bag. Preferably, a steam venting mechanism is formed circumferentially or inward of a circle inscribed in the inner end of the peripheral seal portion.
The steam venting mechanism preferably includes, but is not limited to, a steam vent, a non-bonded portion formed around the steam drain, and a steam vent seal formed around the non-bonded portion.

(Measuring method)
[Load on outermost layer (N / μm)]
Using an outermost layer cut to a width of 10 mm as a sample, a tensile test is performed under the conditions of an atmosphere temperature of 200 ° C., a distance between chucks of 20 mm, and a speed of 1 mm / min. The load at the time when the elongation of 10 mm was 10 mm was measured, and the value was calculated by dividing by the thickness of the outermost layer.
[Water content of film (%)]
The packaging bag (pouch) filled and sealed with the contents (200 ± 50 g) described later is subjected to steam retort sterilization at 121 ° C. for 30 minutes and then stored under an environment of 23 ° C. 70% for 5 days. The multilayer film was measured at 0.1 ± 0.005 g, heated at 230 ° C., and the moisture content of the multilayer film was measured using a trace moisture measuring device CA-200 manufactured by Mitsubishi Chemical Analytech Co., Ltd.

[Heat resistance evaluation]
As a viscous food model such as a commercially available pouch-packed curry for microwave heating, a heat-gelatinized flour model liquid described below was used for a packaging bag (pouch) produced by the method described later. The wheat flour model liquid contains 6% of wheat flour, 1% of cottonseed oil, 1.42% of sodium chloride as inorganic salts, 0.36% of potassium chloride, magnesium chloride hexahydrate as the mass concentration (w / w) to water. 08% (total of 1.86% of inorganic salts) was prepared. The viscosity of this wheat flour model liquid at 80 ° C. was 380 mPa · s as measured by a B-type viscometer at 100 rpm. The wheat flour model liquid was filled with 180 g in a pouch for microwave oven described later and sealed, and then heated for 500 minutes in a microwave oven for 3 minutes, and the following evaluation was performed.
(1) Damage to the Outermost Layer The damage to the outermost layer of the pouch was evaluated as x, and the damage to the outermost layer as 〇.
(2) Perforated Leakage The occurrence of perforations due to microwave oven heating damage of the pouch was visually confirmed, and those with no perforated leakage were evaluated as ○, and those with a perforated leakage were evaluated as ×.

Example 1
The outermost layer is a 12 μm thick biaxially stretched polyethylene terephthalate (PET) film, and the middle layer is a silica as a vapor deposition source, and a vapor deposited film of inorganic oxide is provided on one side (welding layer side) by vacuum vapor deposition A biaxially stretched nylon film, and a welding layer was a 70 μm-thick non-stretched polypropylene (CPP) film. Then, the outermost layer, the intermediate layer, and the welding layer were formed into a multilayer film (water content: 1.0%) in which a vapor deposition film was laminated on the welding layer side by dry lamination using a urethane adhesive. .
Next, the multilayer film is used to form a bag by a three-way seal, and a steam removing mechanism (a steam removing portion with a width of 130 mm, a length of 175 mm, an oblong hole 8 mm wide and a vertical width 2 mm at the upper corner) and a steam releasing portion A pouch for a microwave oven having a non-adhesive portion and a vapor vented seal portion formed around the non-adhesive portion was produced, and the above-described heat resistance evaluation was performed.
The load of the outermost layer in this example was 0.25 N / μm.

(Example 2)
In Example 1, the outermost layer was made of alumina as a vapor deposition source, and a 12 μm thick biaxially stretched polyethylene terephthalate (PET) layer was provided with a vapor deposited film of inorganic oxide on one side by a vacuum vapor deposition method. A pouch for microwave oven was prepared in the same manner except that a butylene terephthalate (PBT) was used, and a multilayer film (water content: 0.3%) in which a vapor deposited film was laminated on the welding layer side was prepared and a pouch for microwave oven was prepared. The heat resistance evaluation described above was performed.
In addition, the load of the outermost layer in a present Example showed 0.23 N / micrometer.

(Example 3)
In Example 2, the intermediate layer is made of a raw material in which polybutylene terephthalate (modified PBT) and polyethylene terephthalate (PET) are mixed at a ratio of modified PBT: PET = 30: 70 to 5:95 (weight ratio). A pouch for a microwave oven was produced in the same manner as in the multilayer film (water content: 0.3%) produced to a thickness of 12 μm, and the heat resistance evaluation described above was performed.
In addition, the load of the outermost layer in a present Example showed 0.23 N / micrometer.

(Example 4)
In Example 2, a pouch for a microwave oven was similarly prepared except that the intermediate layer was made of biaxially stretched polyethylene terephthalate (PET) having a thickness of 12 μm (water content of 0.2% of multilayer film), and the heat resistance described above I made an evaluation.
In addition, the load of the outermost layer in a present Example showed 0.23 N / micrometer.

(Example 5)
In Example 2, except that the intermediate layer was polyethylene naphthalate (PEN) with a thickness of 12 μm (water content of 0.3% of multilayer film), a pouch for microwave oven was similarly prepared, and the heat resistance evaluation described above went.
In addition, the load of the outermost layer in a present Example showed 0.23 N / micrometer.

(Example 6)
In Example 2, except that the intermediate layer was made of polycarbonate (PC) with a thickness of 12 μm (water content of 0.3% of multilayer film), a pouch for microwave oven was similarly prepared, and the above-described heat resistance evaluation was performed. .
In addition, the load of the outermost layer in a present Example showed 0.23 N / micrometer.

(Example 7)
In Example 1, a 12 μm thick biaxially stretched polyethylene terephthalate (PET) provided with a coating film coated with a coating agent consisting of a 25 μm polybutylene terephthalate (PBT) in the outermost layer and a compound having a metalloxane bond in the middle layer The pouch for a microwave oven is prepared in the same manner except that the multilayer film is formed so that the coating film is laminated on the welding layer side (water content of the multilayer film is 0.5%), and the heat resistance evaluation described above is performed. The
The load of the outermost layer in this example was 0.12 N / μm.

(Example 8)
In Example 1, the outermost layer is made of a raw material in which polybutylene terephthalate (modified PBT) and polyethylene terephthalate (PET) are mixed at a ratio of modified PBT: PET = 30: 70 to 5:95 (weight ratio). The film produced to a thickness of 12 μm and the intermediate layer are made of silica as a vapor deposition source, and a 12 μm thick biaxially stretched polyethylene terephthalate (PET) provided with a vapor deposited film of inorganic oxide on one side by vacuum vapor deposition A pouch for a microwave oven was similarly prepared except that a multilayer film was formed so as to be laminated on the side (water content of 0.3% of multilayer film), and the above-described heat resistance evaluation was performed.
The load of the outermost layer in this example was 0.18 N / μm.

(Example 9)
In Example 1, the outermost layer is a 15 μm thick biaxially stretched nylon film, the intermediate layer is alumina as an evaporation source, and a 12 μm thick polyethylene terephthalate (PET film) on one side of which a vapor-deposited film of inorganic oxide is provided by vacuum evaporation. The pouch for a microwave oven was prepared in the same manner as in the above except that the multilayer film (water content: 1.0%) was used so that the deposited film was laminated on the welding layer side, and the above-described heat resistance evaluation was performed.
The load of the outermost layer in this example was 0.20 N / μm.

(Example 10)
In Example 1, the outermost layer is a polyethylene terephthalate (PET) side of a coextruded film of polyethylene terephthalate (PET) with a thickness of 3 μm and polybutylene terephthalate (PBT) with a thickness of 12 μm. The film has a vapor-deposited film of inorganic oxide, and has a two-layer structure with a 70 μm-thick non-oriented polypropylene (CPP) film, and a multilayer film (water content) so that the vapor-deposited film is laminated on the welding layer side 0.2%, and except that the pouch for microwave ovens was produced, the pouch for microwave ovens was similarly produced, and the heat resistance evaluation mentioned above was performed.
In addition, the load of the outermost layer in a present Example showed 0.09 N / micrometer.

(Comparative example 1)
A pouch for a microwave oven was prepared in the same manner as in Example 1 except that the one with a load of 0.28 N / μm was used as the outermost layer of biaxially stretched polyethylene terephthalate (PET), and the above-described heat resistance evaluation was performed. The
The outermost layer of biaxially stretched polyethylene terephthalate (PET) in this comparative example has a load higher than that of the biaxially stretched polyethylene terephthalate (PET) of Example 1 and is greater than 0.25 N / μm, so the outermost layer There was a crack-like damage to the

(Comparative example 2)
In Example 1, the outermost layer is made of silica as a vapor deposition source, and a vapor-deposited film of inorganic oxide is provided on one side by vacuum vapor deposition, 12 μm thick biaxially stretched polyethylene terephthalate (PET), and the intermediate layer is 15 μm thick. Axially stretched nylon film, welding layer is 70 μm thick non-oriented polypropylene (CPP) film, multi-layered film (water content 1.7%) so that deposited film is laminated on welding layer side, pouch for microwave oven The pouch for microwave ovens was similarly produced except having produced, and the heat resistance evaluation mentioned above was performed.
The biaxially stretched polyethylene terephthalate (PET) / alumina deposited film of the outermost layer in the present comparative example is 0.28 N / μm higher in load than the biaxially stretched polyethylene terephthalate (PET) / alumina deposited film of Example 1. Because it is larger than 0.25 N / μm, damage such as cracks was observed in the outermost layer. In addition, the moisture content of the multilayer film was 1.5% or more, and hole leakage was observed.

(Comparative example 3)
In Example 2, a pouch for microwave oven was similarly prepared except that one having a load of 0.36 N / μm was used as the biaxially stretched polyethylene terephthalate (PET) / alumina deposited film as the outermost layer, and the heat resistance described above was used. I did sex evaluation.
The biaxially stretched polyethylene terephthalate (PET) / alumina deposited film of the outermost layer in this comparative example has a load higher than that of the biaxially stretched polyethylene terephthalate (PET) / alumina deposited film of Example 1, and is 0.25 N / Since it was larger than μm, damage such as a crack was observed in the outermost layer.

(Comparative example 4)
In Example 2, a 12 μm thick biaxially stretched polyethylene terephthalate (PET) layer provided with a coating film coated with a coating agent consisting of a compound having a metalloxane bond with a load of 0.32 N / μm at the outermost layer is Using a 25 μm polybutylene terephthalate (PBT), a pouch for a microwave oven was similarly prepared except that a multilayer film was formed so that the coating film was laminated on the welding layer side (0.5% moisture content of multilayer film) The heat resistance evaluation mentioned above was performed.
In addition, since the load of the outermost layer in this comparative example is larger than 0.25 N / μm, damage such as a crack was recognized in the outermost layer.

(Example 11)
In Example 1, the intermediate layer is alumina as a vapor deposition source, and a 12 μm thick biaxially stretched polyethylene terephthalate (PET) and a 15 μm thick biaxially stretched nylon having an evaporated film of inorganic oxide provided on one side by vacuum evaporation. A pouch for a microwave oven was prepared similarly, except that a multilayer film (water content 1.4%) in which a biaxially stretched nylon film was laminated on the welding layer side was used as a laminate of films and a pouch for a microwave oven was produced. The heat resistance evaluation mentioned above was performed.
The load of the outermost layer in this example was 0.25 N / μm.

(Example 12)
In Example 11, a pouch for a microwave oven was prepared in the same manner as in Example 11 except that the outermost layer was made of 15 μm polybutylene terephthalate (PBT) (water content 1.4% of multilayer film), and the above-described heat resistance evaluation was performed. .
The load of the outermost layer in this example was 0.10 N / μm.

(Example 13)
In Example 11, the outermost layer is a coextruded film of 12 μm thick polybutylene terephthalate (PBT) and 3 μm thick polyethylene terephthalate (PET), and the polyethylene terephthalate (PET) side is laminated on the middle layer side A pouch for a microwave oven was similarly produced except that a multilayer film (water content: 1.4%) was used, and the above-described heat resistance evaluation was performed.
In addition, the load of the outermost layer in a present Example showed 0.09 N / micrometer.

(Example 14)
In Example 2, the intermediate layer is a laminate of 12 μm thick biaxially stretched polyethylene terephthalate (PET) and 15 μm thick biaxially stretched nylon film, and the biaxially stretched nylon film is 50 μm thick unstretched polypropylene (CPP) ) The multi-layer film (water content 1.5%) which is made to be laminated on the welding layer made of film, and the pouch for the microwave oven is prepared in the same manner as the pouch for the microwave oven, and the heat resistance evaluation described above Did.
In addition, the load of the outermost layer in a present Example showed 0.23 N / micrometer.

(Comparative example 5)
In Example 11, a pouch for a microwave oven was similarly prepared except that one having a load of 0.28 N / μm was used as biaxially stretched polyethylene terephthalate (PET) as the outermost layer, and the above-described heat resistance evaluation was performed. The
Since the load of the outermost layer was greater than 0.25 N / μm, damage such as cracking was observed in the outermost layer.

(Comparative example 6)
In Example 14, a pouch for a microwave oven was prepared in the same manner as in Example 14 except that the biaxially stretched polyethylene terephthalate (PET) / alumina deposited film of the outermost layer was 0.36 N / μm, and the above-mentioned heat resistance I did sex evaluation.
Since the load of the outermost layer was greater than 0.25 N / μm, damage such as cracking was observed in the outermost layer.

Tables 1 and 2 show experimental results in the above examples and comparative examples.

The heating packaging bag of the present invention is a packaging bag which can be heated by hot water or microwave heating or the like in a state where the contents are filled without opening the packaging bag, and contains oil and metal salt at high concentration. In addition, even if the contents with high viscosity are filled and microwave heating is performed, damage such as perforation of the packaging bag is of course not generated, and cracks on the outer surface do not occur, so it is particularly suitable as a packaging bag for microwave heating. It can be used.

DESCRIPTION OF SYMBOLS 1 Multilayer film, 2 base material layers, 3 barrier layers, 4 welding layers, 5 adhesive layers, 10 packaging bags, 11 bottom parts, 12 side seal parts, 13 top seal parts, 14 storage parts, 15 vapor extraction mechanisms, 16 corner parts , 20 steam vent seal part, 21 non-bonded part, 22 steam vent part.

Claims

A heating packaging bag comprising a multilayer film comprising at least a base layer comprising polyester resin and a welding layer,
In the multilayer film, the sample of the resin film constituting the outermost layer was subjected to tensile test (atmosphere temperature 200 ° C., sample width 10 mm, distance between chucks 20 mm, tensile speed 1 mm / min) when sample elongation was 10 mm A heating packaging bag characterized in that a load per unit thickness is 0.25 N / μm or less.
The outermost layer is any one of a polyethylene terephthalate film, a polybutylene terephthalate film, a film composed of a blend of polyethylene terephthalate and polybutylene terephthalate, a coextruded film of polyethylene terephthalate and polybutylene terephthalate, and a nylon film. The packaging bag for heating as described in 1).
The multilayer film is a multilayer film having a layer structure of a polyethylene terephthalate layer / a deposition layer or a deposition layer or a polyethylene terephthalate layer / a deposition layer in order from the outside, or a polyethylene terephthalate layer / a polybutylene terephthalate having a deposition layer or a coating layer A multilayer film having a layer configuration of a layer / welding layer, or a multilayer film having a layer configuration of a coextruded film of polyethylene terephthalate and polybutylene terephthalate having a deposited layer or a coating layer / welding layer. Packaging bags for heating.
The said packaging bag is a packaging bag for microwave oven heating, Comprising: The moisture content of the said multilayer film in the state by which the content was filled with the packaging bag is 1.0% or less, The said any one of Claims 1-3. Packaging bag for heating.
The packaging bag is a packaging bag for microwave heating, and the moisture content of the multilayer film is 1.5% or less when the packaging bag is filled with contents.
The multilayer film comprises an outermost layer and an intermediate layer, wherein each of the outermost layer and the intermediate layer comprises at least one polyester resin, and the intermediate layer further comprises nylon. Packaging bag for heating as described.
The packaging bag according to any one of claims 4 or 5, further comprising: a steam venting mechanism comprising a steam venting portion, a non-bonded portion formed around the steam drained portion, and a steam venting seal portion formed around the non-bonded portion. Packaging bag for heating as described.