JP2018047954A - bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bag having piercing resistance and permeability. SOLUTION: A laminate constituting a bag 10 having a vapor venting mechanism 20 is, in order from the outer surface side to the inner surface side, a base material / printing layer / adhesive layer / sealant layer, or a base material / transparent vapor deposition layer / transparent. Includes a gas barrier coating film / printing layer / adhesive layer / sealant layer. The substrate contains 51% by weight or more of polybutylene terephthalate. [Selection diagram] Fig. 1

Description

  The present invention relates to a bag provided with a steam release mechanism.

  Conventionally, many cooked or semi-cooked liquids, viscous bodies, or contents in which liquid and solid are mixed are filled and sealed in bags made of plastic laminates. In the bag, the non-seal part to which the laminated bodies are not joined constitutes an accommodation part in which the contents are accommodated. Moreover, the sealing part to which the laminated bodies are joined has sealed the accommodating part. The contents are, for example, cooked foods such as curry, stew, and soup. The contents are heated by a microwave oven or the like while being contained in a bag.

  By the way, if the contents accommodated in the sealed bag are heated using a microwave oven, the moisture contained in the contents evaporates with the heating, and the pressure in the accommodating portion increases. When the pressure in the bag storage portion increases, the bag may rupture and the contents may be scattered to contaminate the inside of the microwave oven. In consideration of such a problem, for example, Patent Documents 1 and 2 provide a steam venting mechanism that automatically communicates the housing portion with the outside when the pressure of the housing portion increases and releases the steam in the housing portion to the outside. is suggesting. The steam release mechanism includes, for example, a steam release seal portion having a weaker seal strength than other seal portions.

JP 2003-182780 A JP 2006-143223 A

  The laminate for constituting the bag is required to have a characteristic that prevents the bag from being broken even when a sharp member with a sharp tip contacts the bag, so-called stab resistance. For this reason, the conventional laminated body is equipped with the film containing nylon which has high puncture resistance. On the other hand, nylon is easy to absorb moisture and has poor heat resistance. In consideration of this point, as a film constituting the bag, a laminate in which a film containing PET, a film containing nylon, and a film containing a thermoplastic resin such as polyethylene are laminated is mainly used. . In this case, the nylon can be prevented from absorbing moisture by providing the nylon between the two films.

  However, nylon has a characteristic that it is easily softened by heat. For this reason, when a laminated body contains nylon, the pressure which arises in a accommodating part when the water | moisture content contained in the content evaporates is utilized for extending the film containing nylon. As a result, the force applied to the steam release mechanism such as the steam release seal portion becomes small, the steam release seal portion cannot be peeled off, and the steam in the housing portion may not be allowed to escape to the outside. is there.

  An object of this invention is to provide the bag which can solve such a subject effectively.

The present invention is a bag having a vapor venting mechanism, and the laminate constituting the bag is a base material / printing layer / adhesive layer / sealant layer or base material / transparent deposition layer in order from the outer surface side to the inner surface side. / Transparent gas barrier coating film / printing layer / adhesive layer / sealant layer,
The base material is a bag containing 51% by mass or more of polybutylene terephthalate.

  In the bag according to the present invention, the base material may contain 60% by mass or more of polybutylene terephthalate.

  In the bag according to the present invention, the puncture strength of the laminate is preferably 13N or more.

  In the bag according to the present invention, the base material may have a multilayer structure including 10 layers or more. Alternatively, the substrate may have a single layer structure having an IV value of 1.10 dl / g or more and 1.35 dl / g or less.

  In the bag according to the present invention, the sealant layer may contain 90% by mass or more of polypropylene.

  In the bag according to the present invention, the sealant layer may further include a thermoplastic elastomer.

In the bag according to the present invention, the laminate includes a base material / a transparent deposition layer / a transparent gas barrier coating film / a printing layer / an adhesive layer / a sealant layer in order from the outer surface side to the inner surface side.
The transparent vapor deposition layer includes aluminum oxide,
A covalent bond between an aluminum atom and a carbon atom may be formed at the interface between the substrate and the transparent vapor deposition layer.

  According to the present invention, a bag formed of a laminate in which two films are laminated can be provided with puncture resistance, and vapor in the housing portion can be released to the outside during heating.

It is a front view which shows the bag in embodiment of this invention. It is an exploded view which shows the film which comprises the bag shown in FIG. It is sectional drawing which shows the case where the bag shown in FIG. 1 is seen along a III-III line. It is sectional drawing which shows an example of the laminated constitution of the laminated body which comprises a bag. It is sectional drawing which shows an example of the laminated constitution of the 1st film of a laminated body. It is sectional drawing which shows the other example of the layer structure of the laminated body which comprises a bag. It is a front view which shows the bag of the state by which the upper part was sealed. It is sectional drawing which shows the case where the bag of the state where the pressure of the accommodating part increased was seen along the VIII-VIII line of FIG. It is sectional drawing which shows the bag by the form of a comparison of the state which the pressure of the accommodating part increased. It is a front view which shows the bag in one modification of embodiment of this invention. It is a figure which shows an example of the measuring method of piercing strength. It is a figure which shows the change of the tensile stress with respect to the tensile length of a test piece. It is a figure which shows an example of the measuring method of seal strength. It is a figure which shows an example of the measuring method of seal strength. It is a figure which shows the change of the tensile stress with respect to the space | interval between a pair of grips which pulls a laminated body in order to measure a seal strength. It is a figure which shows the evaluation result of Examples 1-5 and Comparative Examples 1 and 2. FIG.

  An embodiment of the present invention will be described with reference to FIGS. Note that, in the drawings attached to the present specification, for convenience of illustration and understanding, the scale and vertical / horizontal dimension ratios are appropriately changed and exaggerated from those of the actual ones.

  In addition, as used in this specification, the shape and geometric conditions and the degree thereof are specified, for example, terms such as “parallel”, “orthogonal”, “identical”, length and angle values, etc. are strictly Without being bound by meaning, it should be interpreted including the extent to which similar functions can be expected.

  FIG. 1 is a front view showing a bag 10 according to the present embodiment. FIG. 2 is an exploded view showing a film constituting the bag shown in FIG. The bag 10 includes a storage portion 17 that stores the contents. In addition, in FIG. 1, the bag 10 of the state before being filled with the content is shown. The bag 10 by this Embodiment is comprised so that it can be conveniently used as a pouch for microwave ovens in which the contents are heated with a microwave oven.

  As shown in FIG. 1, the bag 10 according to the present embodiment includes a steam release mechanism 20 for escaping steam generated when the contents contained in the bag 10 are heated to the outside. The steam release mechanism 20 allows the inside and outside of the bag 10 to communicate with each other when the pressure of the steam reaches a predetermined value or more to release the steam, and suppresses the occurrence of steam escape from locations other than the steam release mechanism 20. It is configured as such. Hereinafter, the configuration of the bag 10 will be described.

In the present embodiment, the bag 10 is a gusseted bag configured to be able to stand on its own. The bag 10 includes an upper portion 11, a lower portion 12, and a side portion 13, and has a substantially rectangular outline in a front view. It should be noted that names such as “upper”, “lower” and “side”, and terms such as “upper” and “lower” refer to a bag based on the state in which the bag 10 is self-supporting with the gusset portion down. It is only a relative representation of the position and direction of 10 and its components. The attitude | position at the time of transport of the bag 10 or use is not limited by the name and terminology in this specification.

  As shown in FIGS. 1 and 2, the bag 10 includes a surface film 14 that constitutes the surface, a back film 15 that constitutes the back surface, and a lower film 16 that constitutes the lower portion 12. The lower film 16 is disposed between the front film 14 and the back film 15 in a state where the lower film 16 is folded at the folded portion 16f.

  In addition, the term “surface film”, “back film” and “lower film” described above is merely a partition of each film according to the positional relationship, and the method of providing a film when manufacturing the bag 10 It is not limited by the above terms. For example, the bag 10 may be manufactured using one film in which the front film 14, the back film 15, and the lower film 16 are continuously provided, or one sheet in which the front film 14 and the lower film 16 are continuously provided. It may be manufactured using a total of two films, a film and one back film 15, and a total of three films, one surface film 14, one back film 15, and one lower film 16. May be used.

  As for the surface film 14, the back film 15, and the lower film 16, inner surfaces are joined by the seal part. In the plan view of the bag 10 shown in FIG. 1 and the like, the seal portion is hatched.

  As shown in FIG. 1, the seal portion includes an outer edge seal portion extending along the outer edge of the bag 10 and a steam vent seal portion 20 a constituting the steam vent mechanism 20. The outer edge seal portion includes a lower seal portion 12 a extending in the lower portion 12 and a pair of side seal portions 13 a extending along the pair of side portions 13. In addition, in the bag 10 in a state before being filled with the contents, as shown in FIG. 1, the upper portion 11 of the bag 10 is an opening 11b. After the contents are stored in the bag 10, the inner surface of the front film 14 and the inner surface of the back film 15 are joined at the upper portion 11, whereby an upper seal portion is formed and the bag 10 is sealed.

  The side seal part 13 a, the steam release seal part 20 a, and the upper seal part described later are seal parts configured by joining the inner surface of the surface film 14 and the inner surface of the back film 15. On the other hand, the lower seal portion 12a is formed by bonding the inner surface of the surface film 14 and the inner surface of the lower film 16, and by bonding the inner surface of the back film 15 and the inner surface of the lower film 16. Including a configured seal.

  As long as the opposing films can be bonded to each other and the bag 10 can be sealed, the method for forming the seal portion is not particularly limited. For example, the sealing portion may be formed by melting the inner surfaces of the film by heating or the like and welding the inner surfaces, that is, by heat sealing. Or you may form a seal | sticker part by adhere | attaching the inner surfaces of the opposing film using an adhesive agent etc.

Venting mechanism following describes the structure of venting mechanism 20. FIG. 3 is a cross-sectional view showing a case where the vapor venting mechanism 20 of the bag 10 shown in FIG. 1 is viewed along the line III-III.

  The steam release seal portion 20 a of the steam release mechanism 20 has a shape that is easily peeled off as the pressure in the housing portion 17 increases. For example, the steam release seal portion 20 a has a shape protruding from the side seal portion 13 a toward the inside of the bag 10. Thereby, when the pressure of the accommodating part 17 increases, the force added to the steam release seal part 20a can be made larger than the force applied to the side seal part 13a. Moreover, the width | variety of the steam release seal | sticker part 20a is smaller than the width | variety of the side part seal | sticker part 13a. As shown in FIGS. 1 and 3, a non-seal portion 20 b is formed between the steam release seal portion 20 a and the outer edge of the side portion 13. Thereby, compared with the side seal part 13a, in the steam release seal part 20a, it is possible to easily cause communication between the housing part 17 and the outside due to peeling of the seal part.

Next, the layer structure of the front film 14 and the back film 15 will be described. FIG. 4 is a cross-sectional view showing the laminate 30 that constitutes the front film 14 and the back film 15.

As shown in FIG. 4, the laminate 30 includes a first film 40 and a second film 50 laminated on the first film 40 with an adhesive layer 60 interposed therebetween. The first film 40 is located on the outer surface 30y side, and the second film 50 is located on the inner surface 30x side opposite to the outer surface 30y. The first film 40 includes a base material 41 and a print layer 42. The second film 50 includes a sealant layer 51. Therefore, it can be said that the laminated body 30 by this Embodiment is equipped with the base material / printing layer / adhesive layer / sealant layer in order from the outer surface side to the inner surface side. Note that “/” represents a boundary between layers.

  Hereinafter, each of the first film 40, the second film 50, and the adhesive layer 60 will be described in detail.

(First film)
As shown in FIG. 4, the first film 40 includes at least a base material 41 constituting the outer surface 30 y of the laminate 30 and a printed layer 42 provided on the inner surface 30 x side of the base material 41. The printed layer 42 is a layer printed on the base material 41 in order to show product information or impart aesthetics to the bag 10. The print layer 42 expresses characters, numbers, symbols, figures, patterns, and the like. As a material constituting the printing layer 42, an ink for gravure printing or an ink for flexographic printing can be used. As a specific example of the ink for gravure printing, FINAT manufactured by DIC Graphics Corporation can be given.

  The base material 41 includes polybutylene terephthalate (hereinafter also referred to as PBT) as a main component. For example, the base material 41 includes 51% by mass or more of PBT. Hereinafter, the advantage that the base material 41 includes PBT will be described.

  PBT is excellent in dimensional stability, and therefore excellent in printability. For this reason, the printing layer 42 can be provided on the base material 41 containing PBT similarly to the case of polyethylene terephthalate (hereinafter also referred to as PET).

Moreover, PBT is excellent in heat resistance. For this reason, it is possible to prevent the base material 41 from being deformed or the strength of the base material 41 from being lowered when the bag 10 is subjected to boil processing or retort processing. The retort process is a process of heating the bag 10 in a pressurized state using steam or heated hot water after filling the bag 10 with the contents and sealing the bag 10. The temperature of retort processing is 120 degreeC or more, for example. The boil process is a process of filling the bag 10 with the contents and sealing the bag 10 and then bathing the bag 10 under atmospheric pressure. The temperature of boil processing is 90 degreeC or more and 100 degrees C or less, for example.
Moreover, when PBT has heat resistance, it can suppress that the base material 41 expands with the pressure which arises in the accommodating part 17 when a consumer heats the bag 10. FIG. Thereby, the pressure generated in the housing part 17 can be effectively used as a force for peeling off the steam release seal part 20a of the steam release mechanism 20. For this reason, the vapor | steam in the accommodating part 17 can be escaped outside via the vapor removal mechanism 20 at the time of a heating.

  PBT has high strength. For this reason, the stab resistance can be given to the bag 10 similarly to the case where the laminated body which comprises the bag 10 contains nylon.

  PBT has a characteristic that it is less likely to absorb moisture than nylon. For this reason, even if it is a case where the base material 41 containing PBT is arrange | positioned on the outer surface 30y of the laminated body 30, it suppresses that the base material 41 absorbs a water | moisture content and the laminate strength of the laminated body 30 falls. Can do.

  Hereinafter, the configuration of the base material 41 including PBT will be described in detail. As the configuration of the base material 41 including PBT in the present embodiment, any of the following first configuration or second configuration may be adopted.

[First Configuration of Substrate]
The content of PBT in the base material 41 according to the first configuration is preferably 51% by mass or more, more preferably 60% by mass or more, further 70% by mass or more, particularly preferably 75% by mass or more, and most preferably. 80% by mass or more. By setting the content of PBT to 51% by mass or more, the first film 40 can have excellent impact strength and pinhole resistance.

  PBT used as a main constituent component is preferably 90 mol% or more, more preferably 95 mol% or more, still more preferably 98 mol% or more, most preferably 100 mol% or more of terephthalic acid as a dicarboxylic acid component. Mol%. 1,4-butanediol as the glycol component is preferably 90 mol% or more, more preferably 95 mol% or more, still more preferably 97 mol% or more, and most preferably 1,4-butanediol during polymerization. It is not included except by-products generated by the ether bond of butanediol.

The base material 41 may contain a polyester resin other than PBT. Thereby, for example, the film formability when the film-like substrate 41 is biaxially stretched and the mechanical properties of the substrate 41 can be adjusted.
Polyester resins other than PBT include polyester resins such as PET, polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), and polypropylene terephthalate (PPT), as well as isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, and biphenyldicarboxylic acid. , Cyclohexanedicarboxylic acid, adipic acid, azelaic acid, PBT resin copolymerized with dicarboxylic acid such as sebacic acid, ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, neopentyl glycol, 1,5 -Diols such as pentanediol, 1,6-hexanediol, diethylene glycol, cyclohexanediol, polyethylene glycol, polytetramethylene glycol, polycarbonate diol Min can be mentioned copolymerized PBT resin.

  The amount of the polyester resin other than PBT is preferably 49% by mass or less, and more preferably 40% by mass or less. If the addition amount of the polyester resin other than PBT exceeds 49% by mass, the mechanical properties as PBT may be impaired, and impact strength, pinhole resistance, and drawability may be insufficient.

  The base material 41 may contain, as an additive, a polyester-based and polyamide-based elastomer obtained by copolymerizing at least one of a flexible polyether component, a polycarbonate component, and a polyester component. Thereby, the pinhole resistance at the time of bending can be improved. The additive amount of the additive is, for example, 20% by mass. When the addition amount of the additive exceeds 20% by mass, the effect as the additive may be saturated, or the transparency of the base material 41 may be reduced.

  An example of a method for producing the film-like base material 41 according to the first configuration will be described. Here, a method for producing the film-like base material 41 by a casting method will be described. More specifically, a method of casting a resin having the same composition in multiple layers during casting will be described.

Since PBT has a high crystallization speed, crystallization proceeds even during casting. At this time, when cast as a single layer without being multi-layered, there is no barrier that can suppress the growth of the crystal, so the crystal grows to a large size, and the resulting unstretched original fabric is obtained. The yield stress of becomes higher. For this reason, it becomes easy to fracture when the unstretched original fabric is biaxially stretched. Moreover, it is possible that the yield stress of the obtained biaxially stretched film becomes high and the moldability of the biaxially stretched film becomes insufficient.
On the other hand, if the same resin is multilayered at the time of casting, the stretching stress of the unstretched sheet can be reduced. For this reason, stable biaxial stretching is possible, and the yield stress of the obtained biaxially stretched film is reduced. Thereby, a flexible and high breaking strength film can be obtained.

  FIG. 5 is a cross-sectional view showing an example of the layer configuration of the first film. When the base material 41 is produced by casting the resin in multiple layers, as shown in FIG. 5, the base material 41 of the first film 40 is composed of a multilayer structure including a plurality of layers 41a. Each of the plurality of layers 41a includes PBT as a main component. For example, each of the plurality of layers 41a preferably includes 51% by mass or more of PBT, and more preferably includes 60% by mass or more of PBT. In the plurality of layers 41a, the (n + 1) th layer 41a is directly stacked on the nth layer 41a. That is, no adhesive layer or adhesive layer is interposed between the plurality of layers 41a.

  The reason why the characteristics of the PBT film are improved by the multilayering is estimated as follows. When the resins are laminated, even if the resin composition is the same, a layer interface exists, and crystallization is accelerated by the interface. On the other hand, the growth of large crystals beyond the layer thickness is suppressed. For this reason, it is considered that the size of the crystal (spherulite) becomes small.

  As a specific method for reducing the size of spherulites by multilayering, a general multilayering apparatus (multilayer feedblock, static mixer, multilayer multimanifold, etc.) can be used. For example, for example, a method of laminating thermoplastic resins sent out from different flow paths using two or more extruders using a feed block, a static mixer, a multi-manifold die, or the like can be used. . In addition, when multilayering resin of the same composition, it is also possible to introduce the above multilayering apparatus into the melt line from the extruder to the die using only one extruder.

  The substrate 41 is composed of a multilayer structure including at least 10 layers, preferably 60 layers or more, more preferably 250 layers or more, and still more preferably 1000 layers or more. By increasing the number of layers, the size of spherulites in the unstretched raw PBT can be reduced, and the subsequent biaxial stretching can be carried out stably. Moreover, the yield stress of PBT in the state of a biaxially stretched film can be made small. Preferably, the diameter of the spherulite in the unstretched raw PBT is 500 nm or less.

  The stretching temperature (hereinafter also referred to as MD stretching temperature) in the longitudinal stretching direction (hereinafter referred to as MD) when producing a biaxially stretched film by biaxially stretching the unstretched raw material of PBT is preferably 40 ° C. or higher. Yes, more preferably 45 ° C or higher. By setting the MD stretching temperature to 40 ° C. or higher, the film can be prevented from being broken. Moreover, MD extending | stretching temperature becomes like this. Preferably it is 100 degrees C or less, More preferably, it is 95 degrees C or less. The phenomenon that the orientation of the biaxially stretched film does not occur can be suppressed by setting the MD stretching temperature to 100 ° C. or lower.

  The draw ratio in MD (hereinafter also referred to as MD draw ratio) is preferably 2.5 times or more. Thereby, a biaxially stretched film can be oriented and a favorable mechanical characteristic and uniform thickness can be implement | achieved. MD stretch ratio is 5 times or less, for example.

  The stretching temperature (hereinafter also referred to as TD stretching temperature) in the transverse stretching direction (hereinafter also referred to as TD) is preferably 40 ° C. or higher. By setting the TD stretching temperature to 40 ° C. or higher, the film can be prevented from being broken. The TD stretching temperature is preferably 100 ° C. or lower. By setting the TD stretching temperature to 100 ° C. or lower, the phenomenon that the orientation of the biaxially stretched film does not occur can be suppressed.

  The draw ratio in TD (hereinafter also referred to as TD draw ratio) is preferably 2.5 times or more. Thereby, a biaxially stretched film can be oriented and a favorable mechanical characteristic and uniform thickness can be implement | achieved. MD stretch ratio is 5 times or less, for example.

  The TD relaxation rate is preferably 0.5% or more. Thereby, it can suppress that a fracture | rupture arises at the time of heat setting of the biaxially stretched film of PBT. The TD relaxation rate is preferably 10% or less. Thereby, sagging etc. arise in a biaxially stretched film of PBT, and it can control that thickness unevenness generate | occur | produces.

The thickness of the layer 41a of the base material 41 shown in FIG. 5 is preferably 3 nm or more, more preferably 10 nm or more. The thickness of the layer 41a is preferably 200 nm or less, and more preferably 100 nm or less.
The thickness of the base material 41 is preferably 9 μm or more, and more preferably 12 μm or more. Moreover, the thickness of the base material 41 is preferably 25 μm or less, more preferably 20 μm or less. By setting the thickness of the base material 41 to 9 μm or more, the base material 41 has sufficient strength. Moreover, the base material 41 comes to show the moldability which was excellent by making the thickness of the base material 41 into 25 micrometers or less. For this reason, the process which processes the laminated body 30 containing the base material 41 and manufactures the bag 10 can be implemented efficiently.

[Second Configuration of Base Material]
The base material 41 according to the second configuration is made of a single layer film containing polyester having butylene terephthalate as a main repeating unit. For example, the base material 41 is mainly composed of 1,4-butanediol as a glycol component or an ester-forming derivative thereof and terephthalic acid as a dibasic acid component or an ester-forming derivative thereof, and condenses them. Homo- or copolymer-type polyester obtained. The content of PBT in the base material 41 according to the second configuration is preferably 51% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, further preferably 80% by mass or more, and most preferably. Is 90% by mass or more. Moreover, it is preferable that the base material 41 which concerns on a 2nd structure is comprised only with the polybutylene terephthalate and the additive.

  In order to impart mechanical strength to the substrate 41, PBT having a melting point of 200 ° C. or more and 250 ° C. or less and an IV value (intrinsic viscosity) of 1.10 dl / g or more and 1.35 dl / g or less Is preferred. Furthermore, those having a melting point of 215 ° C. or more and 225 ° C. or less and an IV value of 1.15 dl / g or more and 1.30 dl / g or less are particularly preferable. These IV values may be satisfied by the whole material constituting the base material 41. The IV value can be calculated based on JIS K 7367-5: 2000.

The base material 41 which concerns on a 2nd structure may contain polyester resins other than PBT, such as PET, in 30 mass% or less. When the base material 41 contains PET in addition to PBT, PBT crystallization can be suppressed, and the stretchability of the PBT film can be improved. As PET mix | blended with PBT of the base material 41, the polyester which uses ethylene terephthalate as a main repeating unit can be used. For example, a homotype mainly composed of ethylene glycol as a glycol component and terephthalic acid as a dibasic acid component can be preferably used. In order to impart good mechanical strength characteristics, among PET, those having a melting point of 240 ° C. or more and 265 ° C. or less and an IV value of 0.55 dl / g or more and 0.90 dl / g or less are preferable. Furthermore, those having a melting point of 245 ° C. or more and 260 ° C. or less and an IV value of 0.60 dl / g or more and 0.80 dl / g or less are particularly preferable.
By setting the blending amount of PET to 30% by mass or less, it is possible to suppress the unstretched raw fabric and the stretched film from becoming too rigid. Thereby, a stretched film becomes brittle and it can suppress that the pressure resistance strength, impact strength, puncture strength, etc. of a stretched film fall. Moreover, it is possible to suppress the occurrence of stretching failure when the unstretched raw fabric is stretched.

  The base material 41 is a lubricant, an antiblocking agent, an inorganic extender, an antioxidant, an ultraviolet absorber, an antistatic agent, a flame retardant, a plasticizer, a colorant, a crystallization inhibitor, a crystallization accelerator, if necessary. Etc. may be contained. Further, the polyester resin pellets used as the raw material of the substrate 41 has a moisture content of 0.05% by weight or less, preferably 0.01% by weight or less before heating and melting in order to avoid a decrease in viscosity due to hydrolysis during heating and melting. It is preferable to use after sufficiently pre-drying so that

  An example of a method for producing the film-like substrate 41 according to the second configuration will be described.

  In order to stably produce the film of the base material 41 having the above-described configuration, it is important to suppress the crystal growth in the unstretched raw fabric. Specifically, when forming the film by cooling the extruded PBT melt, the crystallization temperature region of the polymer is cooled at a certain rate or more, that is, the raw fabric cooling rate is an important factor. The raw fabric cooling rate is, for example, 200 ° C./second or more, preferably 250 ° C./second or more, particularly preferably 350 ° C./second or more. Since the unstretched original film formed at a high cooling rate maintains a low crystalline state, the stability of the bubbles during stretching is improved. Furthermore, since film formation at high speed is possible, film productivity is also improved. When the cooling rate is less than 200 ° C./sec, it is considered that the crystallinity of the obtained unstretched original fabric is increased and the stretchability is lowered. In extreme cases, the stretching bubble may burst and stretching may not continue.

  The unstretched original fabric containing PBT as a main component is preferably transported to a space where biaxial stretching is performed while maintaining the atmospheric temperature at 25 ° C. or lower, preferably 20 ° C. or lower. Thereby, even if it is a case where residence time becomes long, the crystallinity of the unstretched original fabric immediately after film-forming can be maintained.

  The biaxial stretching method for obtaining a stretched film by stretching an unstretched raw fabric is not particularly limited. For example, the longitudinal direction and the lateral direction may be simultaneously stretched by the tubular method or the tenter method, or the longitudinal direction and the lateral direction may be sequentially stretched. Among these, the tubular method can obtain a stretched film having a good balance of physical properties in the circumferential direction, and is particularly preferably employed.

  In the tubular method, the unstretched raw material guided to the stretching space is inserted between a pair of low-speed nip rolls, and then heated by a stretching heater while air is pressed into the unstretched raw fabric. After stretching, air is blown onto the stretched film by a cooling shoulder air ring. The stretching ratio is preferably 2.7 times or more and 4.5 times or less for MD and TD, respectively, in consideration of stretching stability, strength physical properties of the stretched film, transparency, and thickness uniformity. By setting the draw ratio to 2.7 times or more, it is possible to sufficiently ensure the tensile elastic modulus and impact strength of the stretched film. In addition, by setting the draw ratio to 4.5 times or less, it is possible to suppress the occurrence of excessive molecular chain distortion due to stretching, and to suppress the occurrence of breakage and puncture during the stretching process, so that the stretched film can be stabilized. Can be produced.

  The stretching temperature is preferably 40 ° C. or higher and 80 ° C. or lower, and particularly preferably 45 ° C. or higher and 65 ° C. or lower. Since the unstretched original fabric produced at the above-described high cooling rate has low crystallinity, the unstretched original fabric can be stably stretched even when the stretching temperature is relatively low. Further, by setting the stretching temperature to 80 ° C. or less, it is possible to suppress stretching bubble shaking and obtain a stretched film with good thickness accuracy. In addition, by setting the stretching temperature to 40 ° C. or higher, it is possible to suppress the occurrence of excessive stretch-oriented crystallization due to low-temperature stretching, thereby preventing whitening of the film.

  The base material 41 produced as described above is constituted by a single layer containing, for example, polyester having butylene terephthalate as a main repeating unit. According to the above-described production method, since the unstretched raw film is formed at a high cooling rate, even when the unstretched raw fabric is constituted by a single layer, a low crystalline state can be maintained, For this reason, an unstretched original fabric can be extended | stretched stably.

  In both the first configuration and the second configuration described above, the base material 41 includes PBT as a main component. For this reason, the tensile elasticity modulus of the laminated body 30 can be made high. In particular, the tensile modulus of elasticity (hereinafter also referred to as hot tensile modulus) of the laminate 30 in a high temperature atmosphere, for example, in an atmosphere of 100 ° C. can be increased. The hot tensile elastic modulus of the laminate 30 is preferably 150 MPa or more, more preferably 160 MPa or more, and further preferably 180 MPa or more. Since the laminated body 30 has a high hot tensile elastic modulus, as shown in the Example mentioned later, the transmissibility of the bag 10 produced using the laminated body 30 is securable. A method for measuring the hot tensile elastic modulus will be described in Example 1 described later.

[Gas barrier layer]
FIG. 6 is a cross-sectional view illustrating another example of the layer configuration of the stacked body 30. As shown in FIG. 6, the 1st film 40 of the laminated body 30 is located in the inner surface 30x side of the base material 41, and may further contain the transparent gas barrier layer 43 which has transparency. In this case, the printing layer 42 is located on the inner surface 30 x side of the transparent gas barrier layer 43. It can be said that the laminate 30 in the example shown in FIG. 6 includes a base material / transparent gas barrier layer / printing layer / adhesive layer / sealant layer in order from the outer surface side to the inner surface side.

Hereinafter, the transparent gas barrier layer 43 will be described. The transparent gas barrier layer 43 is formed on the surface on the inner surface 30x side of the base material 41 and includes at least a transparent vapor deposition layer 43a made of an inorganic material having transparency. The transparent gas barrier layer 43 may further include a transparent gas barrier coating film 43b that is formed on the surface on the inner surface 30x side of the transparent vapor deposition layer 43a and has transparency. In this case, it can be said that the laminated body 30 is provided with a base material / transparent deposition layer / transparent gas barrier coating film / printing layer / adhesive layer / sealant layer in order from the outer surface side to the inner surface side.

  The transparent vapor deposition layer 43a functions as a layer having a gas barrier function that prevents permeation of oxygen gas, water vapor, and the like. Two or more transparent vapor deposition layers 43a may be provided. When it has two or more transparent vapor deposition layers 43a, each may have the same composition or different compositions. Examples of the method for forming the transparent vapor deposition layer 43a include physical vapor deposition (Physical Vapor Deposition, PVD) such as vacuum deposition, sputtering, and ion plating, or plasma chemical vapor deposition, The chemical vapor deposition method (Chemical Vapor Deposition method, CVD method) etc., such as a thermal chemical vapor deposition method and a photochemical vapor deposition method, can be mentioned. Specifically, a vapor deposition layer can be formed on a film formation roller using a roller-type vapor deposition film forming apparatus.

  The transparent vapor deposition layer 43a is formed of an inorganic material having transparency, such as aluminum oxide (aluminum oxide) and silicon oxide. As the transparent vapor deposition layer 43a, it is preferable to use an amorphous thin film of aluminum oxide. Specifically, the transparent vapor deposition layer 43a is an amorphous thin film of aluminum oxide represented by the formula AlOX (wherein X represents a number in the range of 0.5 to 1.5). As the transparent vapor-deposited layer 43a, an amorphous thin film of aluminum oxide in which the value of X decreases in the depth direction from the film surface toward the inner surface can be used. The amorphous thin film of aluminum oxide is represented by the formula AlOX (wherein X represents a number in the range of 0.5 to 1.5), and proceeds in the depth direction from the thin film surface toward the inner surface. It is preferable that the value of X increases. In addition, as a value of X in the above formula, a value of X = 0.5 or more can be basically used. However, when X is less than 1.0, coloring is intense and transparent. Since it is inferior in property, it is preferable to use the thing of X = 1.0 or more. Moreover, since the thing of X = 1.5 is a thing in which Al and oxygen were completely oxidized, the thing to X = 1.5 can be used as an upper limit. In addition, when the value of X in said formula is 0, it is a perfect inorganic simple substance (pure substance), and is not transparent.

  Note that the rate of decrease in the value of X is determined by using a surface analyzer such as an X-ray photoelectron spectrometer (XPS) or a secondary ion mass spectrometer (SIMS) in the depth direction. This can be confirmed by conducting an elemental analysis of the transparent vapor-deposited layer 43a using an analysis method such as ion etching.

  The transparent vapor deposition layer 43a may be a layer made of a mixture of inorganic compounds containing a covalent bond between an aluminum atom and a carbon atom. In this case, the transparent vapor-deposited layer 43a uses an X-ray photoelectron spectrometer (measuring conditions: X-ray source AlKα, X-ray output 120W) and shares aluminum atoms and carbon atoms at the peak measured by ion etching in the depth direction. It may have a gas barrier property that indicates the presence of a bond and has transparency and prevents permeation of oxygen, water vapor, and the like.

  A covalent bond between a metal atom and a carbon atom may be formed at the interface between the transparent vapor deposition layer 43 a and the base material 41. For example, when the transparent vapor deposition layer 43a contains aluminum oxide, the covalent bond of an aluminum atom and a carbon atom shall be formed in the interface of the base material 41 and the transparent vapor deposition layer 43a. The covalent bond can be detected by measurement by X-ray photoelectron spectroscopy (hereinafter referred to as “XPS measurement” for short).

  Moreover, in the transparent vapor deposition layer 43a, all the bonds including the carbon atom observed when the ratio of the covalent bond between the aluminum atom and the carbon atom is measured when the interface between the transparent vapor deposition layer 43a and the substrate 41 is measured by XPS measurement. It is preferable that it is within the range of 0.3% or more and 30% or less. Thereby, the adhesiveness of the transparent vapor deposition layer 43a and the base material 41 is strengthened, transparency is excellent, and the thing of the performance with a good balance is obtained as a gas barrier property vapor deposition film.

  If the ratio of the covalent bond between the aluminum atom and the carbon atom is less than 0.3%, the adhesion of the transparent vapor-deposited layer 43a is not sufficiently improved, and it becomes difficult to stably maintain the barrier property.

Further, the transparent vapor deposition layer 43a mainly composed of aluminum oxide has an AL (aluminum) / O (oxygen) ratio of transparent vapor deposition on the opposite side of the base material 41 from the interface between the base material 41 and the transparent vapor deposition layer 43a. It is preferably 1.0 or less in the range up to 3 nm toward the surface of the layer 43a.
When the AL / O ratio exceeds 1.0 within the range from the interface between the transparent vapor deposition layer 43a and the base material 41 toward the surface of the transparent vapor deposition layer 43a opposite to the base material 41, Adhesiveness with the transparent vapor deposition layer 43a becomes insufficient, the proportion of aluminum increases, and the transparency of the transparent vapor deposition layer 43a decreases.

  The thickness of the transparent vapor deposition layer 43a is, for example, 30 mm or more and 150 mm. If it is less than 30 mm, the gas barrier property may be insufficient even when the transparent gas barrier coating film 43b is used in combination. On the other hand, if it exceeds 150 mm, the gas barrier performance of the laminate 30 may not be maintained. The reason for this is not clear, but if the thickness of the transparent vapor-deposited layer 43a exceeds 150 mm, the flexibility of the laminate 30 is lowered, and when the laminate 30 is used for the bag 10, a part of the transparent vapor-deposited layer 43a is not cracked. It is considered that pinholes are generated and gas barrier properties are lowered. The thickness of the transparent vapor deposition layer 43a is preferably 40 mm or more and 130 mm or less, more preferably 50 mm or more and 120 mm or less. In addition, the thickness of the transparent vapor deposition layer 43a can be measured by a fundamental parameter method using, for example, a fluorescent X-ray analyzer (trade name: RIX2000 type, manufactured by Rigaku Corporation). Moreover, as a means to change the thickness of the transparent vapor deposition layer 43a, it can carry out by the method of changing the deposition rate of the transparent vapor deposition layer 43a, the method of changing the vapor deposition rate, etc.

  In the case where the transparent vapor deposition layer 43a is formed on the inner surface 30x side of the base material 41, the surface of the base material 41 on the inner surface 30x side may be subjected to pretreatment such as corona discharge treatment, frame processing, and plasma processing in advance. Good. In particular, when a covalent bond between a metal atom and a carbon atom is formed at the interface between the transparent vapor deposition layer 43a and the base material 41, the surface of the base material 41 on which the transparent vapor deposition layer 43a is to be formed is pretreated. It is preferable. When the pretreatment is plasma treatment, plasma is supplied to the surface of the base material 41 in a reduced pressure environment of 0.1 Pa or more and 100 Pa or less by the pretreatment apparatus. Plasma uses an inert gas such as argon alone or a mixed gas of oxygen, nitrogen, carbon dioxide and one or more of them as a plasma source gas, and the plasma source gas is excited by a potential difference due to a high-frequency voltage or the like. By doing so, it can be generated.

  By pretreatment, the plasma can be confined in the vicinity of the surface of the substrate 41. Thereby, the shape of the surface of the base material 41, a chemical bonding state, and a functional group can be changed, and the chemical properties of the surface of the base material 41 can be changed. This makes it possible to improve the adhesion between the base material 41 and the transparent vapor deposition layer 43a.

The transparent gas barrier coating film 43b is a layer that functions as a layer that suppresses permeation of oxygen gas, water vapor, and the like. The transparent gas barrier coating film 43b has a general formula R ¹ _n M (OR ² ) _m (wherein R ¹ and R ² represent an organic group having 1 to 8 carbon atoms, and M represents a metal atom). , N represents an integer of 0 or more, m represents an integer of 1 or more, and n + m represents a valence of M), and a polyvinyl alcohol as described above A transparent gas barrier composition containing a benzene-based resin and / or an ethylene / vinyl alcohol copolymer, and further polycondensed by a sol-gel method in the presence of a sol-gel method catalyst, acid, water, and an organic solvent. can get.

As the alkoxide represented by the general formula R ¹ _n M (OR ² ) _m , at least one kind of a partial hydrolyzate of alkoxide and a condensate of hydrolysis of alkoxide can be used. Moreover, as a partial hydrolyzate of said alkoxide, all the alkoxy groups do not need to be hydrolyzed, The thing by which 1 or more was hydrolyzed, and its mixture may be sufficient. As a condensate of hydrolysis of alkoxide, a dimer or more of partially hydrolyzed alkoxide, specifically, a 2 to 6 mer is used.

In the alkoxide represented by the above general formula R ¹ _n M (OR ² ) _m , as the metal atom represented by M, silicon, zirconium, titanium, aluminum, and the like can be used. Examples of preferable metals include silicon and titanium. In the present invention, alkoxides may be used alone or in combination of two or more different metal atom alkoxides in the same solution.

In the alkoxide represented by the above general formula R ¹ _n M (OR ² ) _m , specific examples of the organic group represented by R ¹ include, for example, a methyl group, an ethyl group, an n-propyl group, i Examples thereof include alkyl groups such as -propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-hexyl group, n-octyl group and others. In the alkoxide represented by the general formula R ¹ _n M (OR ² ) _m , specific examples of the organic group represented by R ² include, for example, a methyl group, an ethyl group, an n-propyl group, i -Propyl group, n-butyl group, sec-butyl group, and the like. These alkyl groups in the same molecule may be the same or different.

  When preparing said transparent gas barrier composition, you may add a silane coupling agent etc., for example. As said silane coupling agent, known organic reactive group containing organoalkoxysilane can be used. In particular, an organoalkoxysilane having an epoxy group is preferably used. Specifically, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, or β- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane and the like can be used. The above silane coupling agents may be used alone or in combination of two or more.

(Second film)
The second film 50 includes at least a sealant layer 51 that constitutes the inner surface 30 x of the laminate 30. As a material constituting the sealant layer 51, one or more resins selected from polyethylene such as low density polyethylene and linear low density polyethylene, and polypropylene can be used. The sealant layer 51 may be a single layer or a multilayer. The sealant layer 51 is preferably made of an unstretched film. “Unstretched” is a concept that includes not only a film that is not stretched at all, but also a film that is slightly stretched due to the tension applied during film formation.

  As described above, the bag 10 composed of the laminate 30 is subjected to sterilization treatment such as boil treatment and retort treatment at a high temperature. Therefore, the sealant layer 51 has a heat resistance that can withstand the processing at these high temperatures.

  The melting point of the material constituting the sealant layer 51 is preferably 150 ° C. or higher, and more preferably 160 ° C. or higher. By increasing the melting point of the sealant layer 51, the bag 10 can be retorted at a high temperature, and therefore the time required for the retort process can be shortened. Note that the melting point of the material constituting the sealant layer 51 is lower than the melting point of the resin constituting the substrate 41.

  When considering from the viewpoint of retort processing, a material mainly composed of propylene can be used as a material constituting the sealant layer 51. Here, the material having “propylene as a main component” means a material having a propylene content of 90% by mass or more. Specific examples of the material mainly composed of propylene include propylene / ethylene block copolymer, propylene / ethylene random copolymer, polypropylene such as homopolypropylene, or a mixture of polypropylene and polyethylene. Can do. Here, the “propylene / ethylene block copolymer” means a material having a structural formula represented by the following formula (I). The “propylene / ethylene random copolymer” means a material having a structural formula represented by the following formula (II). “Homopolypropylene” means a material having the structural formula shown by the following formula (III).

  When a material containing propylene as a main component and a mixture of polypropylene and polyethylene is used, the material may have a sea-island structure. Here, the “sea-island structure” means a structure in which polyethylene is discontinuously dispersed in a region where polypropylene is continuous.

When considered from the viewpoint of boil processing, examples of the material constituting the sealant layer 51 include polyethylene, polypropylene, or a combination thereof. Examples of polyethylene include medium density polyethylene, linear low density polyethylene, and combinations thereof. For example, it is also possible to use the materials mentioned as the material constituting the sealant layer from the viewpoint of the above retort processing. The material constituting the sealant layer has a melting point of, for example, 100 ° C. or higher, more preferably 105 ° C. or higher, and still more preferably 110 ° C. or higher. When polyethylene is used as the material constituting the sealant layer, a melting point of 100 ° C. or higher can be realized, for example, when the density of polyethylene is 0.920 g / cm ³ or higher. Specific examples of the sealant film for forming a sealant layer having a melting point of 100 ° C. or higher include TUX-HC manufactured by Mitsui Chemicals Tosero, L6101 manufactured by Toyobo, and LS700C manufactured by Idemitsu Unitech. As a specific example of the sealant film for constituting a sealant layer having a melting point of 105 ° C. or higher, NB-1 manufactured by Tamapoli can be cited. Specific examples of the sealant film for forming a sealant layer having a melting point of 110 ° C. or higher include LS760C manufactured by Idemitsu Unitech, TUX-HZ manufactured by Mitsui Chemicals Tosero, and the like.

  Preferably, the sealant layer 51 includes a propylene / ethylene block copolymer. For example, the second film 50 including the sealant layer 51 is an unstretched film containing a propylene / ethylene block copolymer as a main component. By using the propylene / ethylene block copolymer, the impact resistance of the second film 50 can be increased, and thereby the bag 10 can be prevented from breaking due to the impact at the time of dropping. Moreover, the puncture resistance of the laminated body 30 can be improved.

  Further, by using the propylene / ethylene block copolymer, the strength of the seal portion constituted by the sealant layer 51 (hereinafter also referred to as hot seal strength) at a high temperature, for example, at 100 ° C. or higher is low. For example, it becomes extremely small as compared with the seal strength at room temperature. For example, the hot seal strength at 100 ° C. is ¼ or less of the seal strength at 25 ° C. (hereinafter also referred to as room temperature seal strength). Further, for example, the hot seal strength at a width of 15 mm at 100 ° C. is 20 N or less, preferably 15 N or less. When the seal portion has a low hot seal strength, the vaporability of the bag 10 produced by sealing the laminated body 30 can be ensured as shown in Examples described later. A method for measuring the hot seal strength and the normal temperature seal strength will be described in Example 1 described later.

  The sealant layer 51 may further contain a thermoplastic elastomer. By using a thermoplastic elastomer, the impact resistance and puncture resistance of the second film 50 can be further enhanced.

  The thermoplastic elastomer is, for example, a hydrogenated styrene thermoplastic elastomer. The hydrogenated styrene-based thermoplastic elastomer has a structure comprising a polymer block A mainly composed of at least one vinyl aromatic compound and a polymer block B mainly composed of at least one hydrogenated conjugated diene compound. . The thermoplastic elastomer may be an ethylene / α-olefin elastomer. The ethylene / α-olefin elastomer is a low crystalline or amorphous copolymer elastomer, and is a random copolymer of 50 to 90% by mass of ethylene as a main component and α-olefin as a copolymerization monomer. is there.

  The content of the propylene / ethylene block copolymer in the sealant layer 51 is, for example, 80% by mass or more, and preferably 90% by mass or more.

  Examples of the method for producing a propylene / ethylene block copolymer include a method of polymerizing propylene, ethylene, and the like as raw materials using a catalyst. As the catalyst, Ziegler-Natta type or metallocene catalyst can be used.

  The thickness of the sealant layer 51 is preferably 30 μm or more, more preferably 40 μm or more. Further, the thickness of the sealant layer 51 is preferably 100 μm or less, and more preferably 80 μm or less.

(Adhesive layer)
The adhesive layer 60 includes an adhesive for bonding the first film 40 and the second film 50. Examples of adhesives include ether-based adhesives and ester-based adhesives.

  Examples of the ether-based two-component reactive adhesive include polyether polyurethane. The polyether polyurethane is a cured product produced by a reaction between a polyether polyol as a main agent and an isocyanate compound as a curing agent. As isocyanate compounds, aromatic isocyanate compounds such as tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), etc. Alicyclic isocyanate compounds such as aliphatic isocyanate and isophorone diisocyanate (IPDI), or adducts or multimers of the above-mentioned various isocyanate compounds can be used.

  Examples of the ester-based two-component reactive adhesive include polyester polyurethane and polyester. Polyester polyurethane is a cured product produced by a reaction between a polyester polyol as a main agent and an isocyanate compound as a curing agent. Examples of the isocyanate compound are the same as in the case of the ether-based two-component reactive adhesive described above.

Next, the layer structure of the lower film 16 will be described.

  As long as it has the inner surface which can be joined with the inner surface of the surface film 14 and the inner surface of the back surface film 15, the layer structure of the lower film 16 is arbitrary. For example, similar to the front film 14 and the back film 15, the above-described laminate 30 may be used as the lower film 16. Alternatively, a film having an inner surface constituted by a sealant layer and a configuration different from that of the laminate 30 may be used as the lower film 16.

Method for Manufacturing First Film Next, an example of a method for manufacturing the first film 40 will be described.

  First, a resin material containing PBT as a main component is prepared. Subsequently, the film-like base material 41 is produced by extruding a resin material by a melt extrusion method such as a cast method or a tubular method. Subsequently, an inorganic material such as aluminum oxide may be vapor-deposited on the film-like substrate 41 to form the transparent vapor-deposited layer 43a. Subsequently, a transparent gas barrier coating composition 43b may be formed by applying a transparent gas barrier composition on the transparent vapor deposition layer 43a. Thereafter, the printing layer 42 is formed on the substrate 41 or the transparent gas barrier coating film 43b. Thus, the 1st film 40 provided with the base material 41 and the printing layer 42, or the base material 41, the transparent gas barrier layer 43 containing the transparent vapor deposition layer 43a and the transparent gas barrier coating film 43b, and the printing layer 42. The 1st film 40 provided with these can be obtained.

Method for producing a laminate Next, an example of a method for producing a laminate 30.

  First, the second film 50 including the first film 40 and the sealant layer 51 described above is prepared. Subsequently, the first film 40 and the second film 50 are laminated via the adhesive layer 60 by a dry laminating method. Thereby, the laminated body 30 provided with the 1st film 40 and the 2nd film 50 can be obtained.

Manufacturing method of bag The front film 14 and the back film 15 which consist of the above-mentioned laminated body 30 are prepared. In addition, the lower film 16 in a folded state is inserted between the front film 14 and the back film 15. Subsequently, the inner surfaces of the films are heat-sealed to form seal portions such as the lower seal portion 12a and the side seal portion 13a. Further, the films bonded to each other by heat sealing are cut into an appropriate shape to obtain a bag 10 shown in FIG. Subsequently, the contents 18 are filled into the bag 10 through the opening 11 b of the upper portion 11. The contents 18 are cooked foods containing moisture, such as curry, stew, and soup. In addition to food, items that can be heated by hot water can be stored in the bag 10 as contents. Thereafter, the upper part 11 is heat-sealed to form the upper seal part 11a. Thus, as shown in FIG. 7, the bag 10 in which the contents 18 are accommodated and sealed can be obtained.

Heating method of the contents Next, an example of a method for heating the contents 18 contained in the bag 10.

  First, the bag 10 is placed inside the microwave oven in a state where the bag 10 is self-supporting with the lower portion 12 facing down. Next, the contents are heated using a microwave oven. As a result, the temperature of the contents 18 increases, and accordingly, the water contained in the contents 18 evaporates and the pressure in the accommodating portion 17 increases. FIG. 8 is a cross-sectional view showing a case where the bag 10 in a state in which the pressure in the housing portion 17 is increased is viewed along the line VIII-VIII in FIG. 7.

  When the pressure in the housing part 17 increases, the surface film 14 and the back film 15 swell outward due to the force F2 received from the housing part 17 as shown in FIG. Here, in this Embodiment, the laminated body 30 which comprises the surface film 14 and the back film 15 contains the base material 41 which has PBT as a main component. For this reason, the rigidity of the base material 41 is high. As a result, when the front film 14 and the back film 15 receive the force F2, the base material 41 in the front film 14 and the back film 15 is prevented from extending. Can do. Thereby, as shown in FIG. 8, the force generated due to the pressure generated in the accommodating portion 17 is not the force F2 for extending the front surface film 14 and the back surface film 15, but for peeling off the steam release seal portion 20a. It can be mainly used as the force F1. For this reason, the force F1 applied to the steam release seal portion 20a can be increased. Thus, the steam release seal portion 20a is easily peeled off during heating, and the steam in the housing portion 17 can be released to the outside via the steam release mechanism 20.

  Next, the effect of this embodiment will be described in comparison with a comparative embodiment. In the comparative form, the outer surface of the laminate 130 constituting the front film 14 and the back film 15, that is, the base material is made of nylon. The heat resistance of nylon is lower than that of PBT or PET. For this reason, when the pressure of the accommodating part 17 becomes high, the nylon in the laminated body 130 will extend with a sealant layer, and the surface film 14 and the back film 15 will swell outside. As described above, in the comparative embodiment, the pressure generated in the accommodating portion 17 is mainly used to stretch the laminated body 130 containing nylon, and therefore the force F1 applied to the steam release seal portion 20a cannot be increased. . For this reason, it is possible that the laminated body 130 is torn before the vapor vent seal portion 20a is peeled off, or the seal portions other than the vapor vent seal portion 20a are peeled off.

  On the other hand, according to this Embodiment, since the laminated body 30 which comprises the surface film 14 and the back surface film 15 contains the base material 41 which has PBT as a main component, the hot tensile elasticity modulus of the laminated body 30 Can be high. For this reason, the force F1 applied to the vapor vent seal part 20a during heating can be increased. Thereby, it can suppress that the laminated body 30 is torn before the vapor vent seal part 20a peels off, or seal parts other than the vapor vent seal part 20a peel off. That is, the vapor permeability of the bag 10 can be ensured.

  Moreover, according to this Embodiment, the sealant layer 51 of the laminated body 30 which comprises the surface film 14 and the back film 15 contains a propylene and ethylene block copolymer. For this reason, the hot seal strength of the sealant layer 51 at a high temperature can be lowered, and thereby, the steam release seal portion 20a is more easily peeled off during heating. Therefore, the vapor permeability of the bag 10 can be further improved. Moreover, when the sealant layer 51 further contains an elastomer, the impact resistance and puncture resistance of the second film 50 can be enhanced.

Moreover, according to this Embodiment, when the laminated body 30 which comprises the surface film 14 and the back surface film 15 contains the base material 41 which has PBT as a main component, there can exist the following effect.
First, PBT is excellent in printability. For this reason, the printing layer 42 can be provided on the base material 41 containing PBT similarly to the case of polyethylene terephthalate (hereinafter also referred to as PET).
Moreover, PBT is excellent in heat resistance. For this reason, it is possible to prevent the base material 41 from being deformed or the strength of the base material 41 from being lowered when the bag 10 is subjected to boil processing or retort processing.
PBT has high strength. For this reason, puncture resistance can be given to the laminated body 30 and the bag 10 similarly to the case where the laminated body which comprises the bag 10 contains nylon. The puncture strength of the laminate 30 is preferably 13N or more, more preferably 15N or more, and further preferably 17N or more. A method for measuring the puncture resistance will be described in Example 1 described later.
PBT has a characteristic that it is less likely to absorb moisture than nylon. For this reason, even if it is a case where the base material 41 containing PBT is arrange | positioned on the outer surface 30y of the laminated body 30, it suppresses that the base material 41 absorbs a water | moisture content and the laminate strength of the laminated body 30 falls. Can do.

  Note that various modifications can be made to the above-described embodiment. Hereinafter, modified examples will be described with reference to the drawings as necessary. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above embodiment are used for the parts that can be configured in the same manner as in the above embodiment. A duplicate description is omitted. In addition, when it is clear that the operational effects obtained in the above-described embodiment can be obtained in the modified example, the description thereof may be omitted.

(Bag variant)
In the above-described embodiment, an example in which the bag 10 is a gusset type bag has been shown, but the specific configuration of the bag 10 is not particularly limited. For example, as shown in FIG. 10, the bag 10 is a so-called four-way seal formed by joining the inner surfaces of the front film 14 and the rear film 15 made of the laminate 30 at the upper part 11, the lower part 12 and the side part 13. It may be a bag.

  EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to description of a following example, unless the summary is exceeded.

Example 1
A film-like base material 41 including a plurality of layers 41a described in the first configuration and manufactured by a casting method was prepared. The content of PBT in each layer 41a was 80%, the number of layers 41a was 1024, and the thickness of the base material 41 was 15 μm. Subsequently, the print layer 42 was formed on the film-like base material 41 using a finart manufactured by DIC Graphics Corporation.

  In addition, a film-like second film 50 including the sealant layer 51 was prepared. As the sealant layer 51, an unstretched polypropylene film ZK500 manufactured by Toray Film Processing Co., Ltd. was used. ZK500 contains the above-mentioned propylene / ethylene block copolymer and elastomer. The thickness of the sealant layer 51 was 60 μm.

  Then, the 1st film 40 and the 2nd film 50 were laminated | stacked through the adhesive bond layer 60 with the dry lamination method, and the laminated body 30 was produced. As the adhesive layer 60, a two-component polyurethane adhesive (main agent: RU-40, curing agent: H-4) manufactured by Rock Paint Co., Ltd. was used. In addition, RU-40 of the main ingredient is a polyester polyol.

  Subsequently, the piercing strength of the laminate 30 was measured in accordance with JIS Z1707 7.4. As a measuring device, Tensilon universal material testing machine RTC-1310 manufactured by A & D was used. Specifically, as shown in FIG. 11, a semicircular needle 70 having a diameter of 1.0 mm and a tip shape radius of 0.5 mm from the outer surface 30y side with respect to the test piece of the laminated body 30 in a fixed state. Was stabbed at a speed of 50 mm / min (50 mm per minute), and the maximum value of the stress until the needle 70 penetrated the laminate 30 was measured. About five or more test pieces, the maximum value of stress was measured, and the average value was defined as the piercing strength of the laminate 30. The environment during the measurement was a temperature of 23 ° C. and a relative humidity of 50%. As a result, the piercing strength was 16N.

  In addition, in an atmosphere at 100 ° C., the tensile modulus of elasticity (hereinafter also referred to as hot tensile modulus) of the laminate 30 was measured according to JIS K7127. As a measuring device, a tensile tester RTC-1310A with a constant temperature bath manufactured by Orientec Co., Ltd. was used. Specifically, first, the laminate 30 was cut out to produce a rectangular test piece having a width (short side) of 15 mm. Thereafter, the test piece was pulled at a speed of 50 mm / min in the long side direction, and the tensile stress applied to the test piece was measured. Ten specimens were measured for tensile stress. For each test piece, the maximum value of the tensile stress gradient k (see FIG. 12) was calculated. And the average value of the maximum value of the inclination k of each test piece was made into the hot tensile elasticity modulus of the laminated body 30. FIG. As a result, the hot tensile elastic modulus was 164 MPa.

Subsequently, the inner surfaces 30x of the two laminates 30 were partially heat sealed. Then, the sealing strength between the laminated bodies 30 was measured based on JISZ17077.5 in 100 degreeC atmosphere. As a measuring device, a tensile tester RTC-1310A with a constant temperature bath manufactured by Orientec Co., Ltd. was used. Specifically, first, two heat-sealed laminates 30 were cut out to produce a rectangular test piece 80 having a width (short side) of 15 mm. In the test piece 80, as shown to FIG. 13A, the two laminated bodies 30 are peeled over 15 mm from one front-end | tip of the long side direction. Thereafter, as shown in FIG. 13B, the already peeled portions of the two laminates 30 were each gripped by the gripping tool 81 and the gripping tool 82 of the measuring instrument. Further, each of the grips 81 and 82 is pulled at a speed of 300 mm / min in opposite directions in the direction orthogonal to the surface direction of the portion where the two laminated bodies 30 are still joined, Values (see FIG. 14) were measured. FIG. 14 is a diagram showing changes in tensile stress with respect to the spacing S. FIG.
For the five test pieces 80, the maximum value of the tensile stress was measured, and the average value was taken as the seal strength of the laminate 30. The spacing S between the gripping tools 81 and 82 when starting the pulling was 20 mm, and the spacing S between the gripping tools 81 and 82 when finishing the pulling was 40 mm. The environment during the measurement was a temperature of 100 ° C. and a relative humidity of 50%. As a result, the seal strength at 15 mm width (hereinafter also referred to as hot seal strength) was 13N. Further, the seal strength was measured in the same manner as described above except that the environment during measurement was 23 ° C. and the relative humidity was 50%. As a result, the seal strength at 15 mm width (hereinafter also referred to as room temperature seal strength) was 61N.

  Then, the bag 10 was produced using the laminated body 30, and the vapor permeability of the bag 10 was evaluated. Specifically, first, the bag 10 shown in FIG. Thereafter, 100 g of water was filled in the bag 10, and the upper part 11 was heat-sealed to form an upper seal part 11a. At this time, the length S1 of the bag 10 was 145 mm, and the length S2 was 140 mm. Subsequently, the contents were heated using a microwave oven, and it was confirmed whether or not the vapor vent seal portion 20a of the vapor vent mechanism 20 was properly peeled off. As a result, the steam release seal part 20a was peeled off, and the steam in the housing part 17 was able to escape to the outside.

(Example 2)
As the base material of the first film, the PBT containing 100% by mass described in the second configuration described above is included, the melting point of the PBT is 224 ° C., and the IV value is 1.26 dl / g. A laminate was prepared in the same manner as in Example 1 except that the film-like base material 41 was used. The base material 41 was a single layer film composed only of PBT and an additive, and the thickness of the base material 41 was 15 μm. Further, the puncture strength and hot tensile elastic modulus of the laminate were measured in the same manner as in Example 1. As a result, the piercing strength was 15 N, and the hot tensile elastic modulus was 211 MPa.

  Further, the sealing strength of the laminate 30 was measured in the same manner as in Example 1. As a result, the hot seal strength at 15 mm width was 13 N, and the normal temperature seal strength at 15 mm width was 61 N. Moreover, the vapor permeability of the bag 10 produced using the laminated body 30 was evaluated in the same manner as in Example 1. As a result, the steam release seal part 20a was peeled off, and the steam in the housing part 17 was able to escape to the outside.

(Example 3)
A laminate was produced in the same manner as in Example 1 except that an unstretched polypropylene film ZK99S manufactured by Toray Film Processing Co., Ltd. was used as the second film. Further, the puncture strength and hot tensile elastic modulus of the laminate were measured in the same manner as in Example 1. As a result, the puncture strength was 16 N, and the hot tensile elastic modulus was 181 MPa.

  Further, the sealing strength of the laminate 30 was measured in the same manner as in Example 1. As a result, the hot seal strength at 15 mm width was 28 N, and the normal temperature seal strength at 15 mm width was 68 N. Moreover, the vapor permeability of the bag 10 produced using the laminated body 30 was evaluated in the same manner as in Example 1. As a result, the steam release seal part 20a was peeled off, and the steam in the housing part 17 was able to escape to the outside.

Example 4
A laminate was produced in the same manner as in Example 2 except that an unstretched polypropylene film ZK99S manufactured by Toray Film Processing Co., Ltd. was used as the second film. Further, the puncture strength and hot tensile elastic modulus of the laminate were measured in the same manner as in Example 1. As a result, the piercing strength was 15 N, and the hot tensile elastic modulus was 198 MPa.

  Further, the sealing strength of the laminate 30 was measured in the same manner as in Example 1. As a result, the hot seal strength at 15 mm width was 28 N, and the normal temperature seal strength at 15 mm width was 68 N. Moreover, the vapor permeability of the bag 10 produced using the laminated body 30 was evaluated in the same manner as in Example 1. As a result, the steam release seal part 20a was peeled off, and the steam in the housing part 17 was able to escape to the outside.

(Comparative Example 1)
A laminate was produced in the same manner as in Example 1 except that a nylon film having a thickness of 15 μm (Bonyl W manufactured by Kojin Holdings Co., Ltd.) was used as the base material of the first film. Further, the puncture strength and hot tensile elastic modulus of the laminate were measured in the same manner as in Example 1. As a result, the piercing strength was 15 N and the hot tensile elastic modulus was 145 MPa.

  Further, the sealing strength of the laminate was measured in the same manner as in Example 1. As a result, the hot seal strength at 15 mm width was 13 N, and the normal temperature seal strength at 15 mm width was 61 N. Moreover, the vapor permeability of the bag produced using the laminated body was evaluated in the same manner as in Example 1. As a result, the steam release seal portion of the steam release mechanism could not be peeled off.

(Comparative Example 2)
A laminate was produced in the same manner as in Example 1 except that a PET film having a thickness of 12 μm (T4102 manufactured by Toyobo Co., Ltd.) was used as the base material of the first film. Further, the puncture strength and hot tensile elastic modulus of the laminate were measured in the same manner as in Example 1. As a result, the puncture strength was 10 N, and the hot tensile elastic modulus was 343 MPa.

  Further, the sealing strength of the laminate was measured in the same manner as in Example 1. As a result, the hot seal strength at 15 mm width was 13 N, and the normal temperature seal strength at 15 mm width was 61 N. Moreover, the vapor permeability of the bag produced using the laminated body was evaluated in the same manner as in Example 1. As a result, the steam release seal part was peeled off, and the steam in the housing part was able to escape to the outside.

  The evaluation results of Examples 1 to 4 and Comparative Examples 1 and 2 are collectively shown in FIG. As can be seen from the comparison between Examples 1 to 4 and Comparative Example 1, the first film 40 of the laminate 30 includes PBT, thereby ensuring the vapor permeability in the bag 10 produced using the laminate 30. did it. In addition, regarding steamability, in Examples 1 to 4 and Comparative Example 2, during heating, the seal part other than the steam vent seal part 20a did not retreat (peel), and the steam in the housing part escaped to the outside. The evaluation result was “great” or “good”. Further, in Examples 1 and 2 and Comparative Example 2, the pressure in the housing part when the steam release seal part peels off and the steam in the housing part begins to escape to the outside is smaller than in Examples 3 and 4. Therefore, the evaluation result was set to “great”. Moreover, about the comparative example 1, since the vapor | steam in an accommodating part escaped outside from the seal parts other than the vapor removal seal | sticker part 20a at the time of a heating, the evaluation result was set to "bad".

  The lower the hot seal strength of the steam vent seal portion 20a, the easier the steam vent seal portion 20a peels during heating. Further, the higher the hot tensile elastic modulus of the laminate 30 is, the more the force applied to the steam release mechanism 20 during heating is concentrated on the second film 50 including the sealant layer 51 instead of the first film 40 including the base material 41. Can do. Therefore, the lower the hot seal strength and the higher the hot tensile elastic modulus, the easier the steam release seal portion 20a is peeled off during heating, and the steam in the housing portion is more likely to escape to the outside. That is, the permeability is improved. As shown in FIG. 15, in Examples 1 and 2 and Comparative Example 2, the hot seal strength is 20 N or less and the hot elastic tensile modulus is 150 MPa or more. For this reason, in Examples 1 and 2 and Comparative Example 2, it is considered that good vapor permeability was obtained.

  Moreover, as can be seen from the comparison between Examples 1 to 4 and Comparative Example 2, when the first film 40 of the laminate 30 includes PBT, a high piercing strength can be realized as compared with the case of using PET. It was.

DESCRIPTION OF SYMBOLS 10 Bag 11 Upper part 11a Upper seal part 12 Lower part 12a Lower seal part 13 Side part 13a Side part seal part 14 Surface film 15 Back surface film 16 Lower film 17 Storage part 18 Contents 20 Steam release mechanism 20a Steam release seal part 20b Non-seal part 30 Laminate 40 First Film 41 Base 41a Layer 42 Printed Layer 43 Transparent Gas Barrier Layer 43a Transparent Deposition Layer 43b Transparent Gas Barrier Coating Film 50 Second Film 51 Sealant Layer 60 Adhesive Layer 70 Needle 80 Test Piece 80a Sealing Portion 80b Non- Seal part

Claims (8)

A bag having a steam release mechanism,
The laminated body constituting the bag is a base material / printing layer / adhesive layer / sealant layer or base material / transparent vapor deposition layer / transparent gas barrier coating film / printing layer / adhesive in order from the outer surface side to the inner surface side of the laminated body. Layer / sealant layer,
The base material is a bag containing 51% by mass or more of polybutylene terephthalate.   The bag according to claim 1, wherein the base material contains 60% by mass or more of polybutylene terephthalate.   The bag of Claim 1 or 2 whose puncture strength of the said laminated body is 13 N or more.   The said base material is a bag as described in any one of Claims 1 thru | or 3 which has a multilayered structure part containing 10 layers or more.   The bag according to any one of claims 1 to 3, wherein the base material has a single-layer structure having an IV value of 1.10 dl / g or more and 1.35 dl / g or less.   The bag according to any one of claims 1 to 5, wherein the sealant layer contains 90% by mass or more of polypropylene.   The bag according to any one of claims 1 to 6, wherein the sealant layer includes a thermoplastic elastomer. The laminate includes, in order from the outer surface side to the inner surface side, a base material / transparent vapor deposition layer / transparent gas barrier coating film / printing layer / adhesive layer / sealant layer.
The transparent vapor deposition layer includes aluminum oxide,
The bag as described in any one of Claims 1 thru | or 7 in which the covalent bond of the aluminum atom and the carbon atom is formed in the interface of the said base material and the said transparent vapor deposition layer.

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