JP4103261B2 - Retort sterilization-compatible bag for oily food filling - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a bag-like container for containing oily food that can be circulated at room temperature by retort sterilization, a film for the container, and an oily retort food filled in the container.
[0002]
[Prior art]
As is well known, retort foods are foods that can be circulated at room temperature for a long period of time by sterilization under pressure and heat. However, if the contents are oily foods, In some cases, fine irregularities are formed on the surface of the laminate container, and the appearance of the outer surface of the container is impaired.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a bag-like container suitable for an oil-based food that does not impair the appearance of the outer surface of the container without causing fine irregularities on the surface of the bag-like container for storing the oil-based food.
[0004]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have found that in a bag-like container made of a conventional laminate, the oil in the food moves to the innermost heat-resistant sealant layer during retort processing. It was found that the heat-resistant sealant layer swells and deforms, which causes deformation of the entire laminate, and minute irregularities are generated on the surface of the bag-like container. Further, in a bag-like container comprising a laminate in which the innermost heat-resistant sealant layer is a laminate of at least two layers and the laminate between the sealant layers is non-adhesive, weakly-adhered or partially adhered, the bag-like container after retorting The present invention was completed by finding that minute irregularities were not generated on the surface of the film.
[0005]
That is, the present invention includes a heat-resistant outer layer and a heat-resistant sealant layer made of at least one resin selected from polyethylene terephthalate, nylon and stretched polypropylene, and between the heat-resistant outer layer and the heat-resistant sealant layer. a laminate having a barrier layer, the laminate-free adhesive heat-resistant sealant layer constituting the innermost layer of the two or more layers, laminated structure that is dry lamination except that it is weakly bonded or partially bonded In addition, in the sealed portion around the container, the laminated body and the heat-resistant sealant layer of the laminated body are completely adhered to each other, and the bag container for retort sterilization for filling with oil-based foods is provided.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, an oily food is a general meaning of a food having a high oil component, and even a food having a low oil component is released during retort processing, so that the oil component itself directly contacts the inner surface of the container. It also contains such foods.
[0007]
Oily foods are known to often release oil components when subjected to high-temperature heat treatment such as retort treatment, but when the oily foods are retorted, minute irregularities are generated on the surface of the bag-like laminate container. It was often seen. Such minute unevenness is called “skin skin” and has been a factor of deteriorating the product value by deteriorating the aesthetic appearance of the outer surface of the container.
[0008]
The cause of the occurrence of “skin skin” has not been completely elucidated until now, but the present inventor has conducted a combination of oil-based foods that are known to cause skin skin and a bag-like laminate container for retort. In addition, the following experiments revealed that one of the major causes is that the inner sealant swells and deforms due to the influence of oil components released during retort processing.
[0009]
That is, a sealant film made of the same material as the innermost layer sealant of the bag-like laminate container is laminated on the inner layer side of the laminate material in a non-adhesive state to form a bag-like container, and after filling the oily food, normal conditions The retort treatment was performed below. As a result, clear wrinkles were generated only in the laminated sealant film, but no skin was formed on the surface of the outer laminated material. In addition, the layered sealant film showed clear elongation from the original dimensions when the wrinkles were stretched, and it was clear that the layers were swollen and deformed.
[0010]
To summarize the above results, when the oil component comes into direct contact with the inner surface of the container during heating, the sealant layer on the inner surface of the container swells and deforms, resulting in deformation of the laminate material, resulting in a crusted skin. When not firmly bonded, the swelling / deformation stops only in the innermost sealant film and does not cause deformation of the laminate material.
[0011]
The present invention further extends the principle. Even when the innermost layer sealant film is weakly or partially bonded to the laminate, the swelling / deformation that occurs during the retort treatment is limited to the innermost layer sealant film, and the laminate material is deformed. It was confirmed that it did not occur.
[0012]
The film, which is a laminate used in the bag container suitable for retort sterilization suitable for oil-based foods in the present invention, comprises at least a heat-resistant outer layer and a heat-resistant sealant layer.
[0013]
As the heat-resistant outer layer in the present invention, one having a structure generally used for a retort packaging is used without particular limitation, and a heat-resistant resin layer such as polyethylene terephthalate, nylon, stretched polypropylene, etc. is used as an outermost layer, an aluminum foil, A preferable example is a laminate in which a barrier layer such as an aluminum vapor-deposited heat-resistant resin layer and an ethylene vinyl alcohol copolymer resin layer, and a reinforcing layer that improves puncture resistance such as nylon are laminated in order.
[0014]
The heat-resistant outer layer in the present invention is preferably an opaque material that cannot be seen through the deformation and swelling generated in the innermost layer sealant, and an aluminum foil, an aluminum vapor-deposited heat-resistant resin layer, or a transparent resin material that is entirely printed with an opaque ink is used. Is preferred.
[0015]
Although there is no restriction | limiting in particular in the lamination | stacking method of the laminated body in this invention, The dry lamination method with retort tolerance is applied preferably except the lamination | stacking between inner layer sealants.
[0016]
As the inner layer sealant material in the present invention, a retort-resistant sealant material is used without any particular limitation. However, a polyolefin resin is preferable because it has good heat sealability, and is preferably a polypropylene resin, a heat-resistant linear low-density polyethylene resin, A density polyethylene resin is more preferably used.
[0017]
Different resins can be used as the resin constituting the laminated inner layer sealant as long as they can be mixed under the heat sealing conditions applied at the time of container molding to obtain sufficient sealing strength, but the same resin was used. In this case, it is more preferable in that it can be easily and completely welded during heat sealing.
[0018]
The method for laminating the inner layer sealant in the present invention is not particularly limited as long as it is non-adhesive, weakly adhering, or partial adhering, and dry laminating, thermal laminating, and extrusion laminating methods are used. A thermal laminating method in which pressure bonding is performed between heated rolls is more preferably used as a method for realizing weak adhesion or partial adhesion. Although an adhesive can be used as the method of weak adhesion or partial adhesion, thermal welding is a more preferable method in the practice of the present invention.
[0019]
The adhesive strength between the portions adhered inner layer sealant of the present invention is preferably from 500g as the adhesive strength of 15 mm wide is used as an indicator of general adhesive strength, and more preferably not more than 300 g.
[0020]
Preferably adhesion sites between the inner sealant was partially adhered in the present invention the maximum width of the adhered portion is 10 mm or less, more preferably 5 mm. When the width of the bonded portion is wide, minute irregularities generated in the bonded portion become clear, and the result does not meet the object of the present invention.
[0021]
Although there is no restriction | limiting in the pattern shape of the adhesion site | part partially adhered in this invention, Shapes, such as a lattice pattern and a polka dot pattern, can be illustrated as a preferable shape. The heat laminating method in which the film material is heat-pressed through a surface-processed roll is preferably used as a method capable of continuously bonding the film material. Part strength of the adhesive is no limitation, it may be an adhesive or 500g following weakly joining more than 500g as the adhesive strength of 15 mm width.
[0022]
Although spacing portion adhered adhesion sites of the present invention the above 5 mm is selected, preferably 10 mm to 70 mm from the processing proper of the bag-shaped container as an upper limit of the interval. If the interval is too wide, the non-adhesive portion may adversely affect the opening characteristics of the bag-like container.
[0023]
Although there is no limit to the total thickness of the sealant layer is preferably not less than 45μ m, more 50.mu. m and more preferably in container cold strength surface.
[0024]
Although there is no restriction | limiting in the shape of the bag-shaped container which processed and molded the laminated film in this invention, Self-standing bags, such as a 3-way seal bag, a 4-way seal bag, a boat-shaped bottom shape, or a gusset-shaped bag are illustrated as suitable shapes. Is done. A bag-like container in which a mouth made of heat-resistant plastic is provided in a part of the shape bag is also preferably exemplified. The heat sealing in this case may be performed by a normal method, and as a condition, it is preferably performed at a temperature higher than the melting point of the sealant layer and lower than the heat resistance temperature of the outer layer, intermediate layer, barrier layer, and the like.
[0025]
The oily food according to the present invention refers to a food in which the oily component is liberated during retort processing and comes into direct contact with the innermost sealant material regardless of the content of the oily component. Processed foods such as beef curry, cooked hamburger and other processed meat products, roast chicken, grilled chicken and other processed poultry meat products, grilled fish and seafood processed foods such as miso-boiled miso, and combined seasonings containing oily ingredients And cooking sauces are exemplified.
[0026]
Hereinafter, the content of the present invention will be described with reference to examples, but the content of the present invention is not limited to the examples.
[0027]
[Example 1]
Polyethylene terephthalate 12 [mu m than the outer layer, the aluminum foil 7 microns m and 6-nylon -12Myu m, to prepare a heat-resistant outer layer laminate are sequentially dry lamination using an aliphatic urethane adhesive. After dry-laminating an unstretched polypropylene 25.mu. m inside of the outer layer laminate with an aliphatic urethane based adhesive, superimposed further unstretched polypropylene 30.mu. m without adhesive, 2 sheets of facing an inner layer on the inside The three sides of each were heat sealed at 180 ° C. to prepare a 20 cm × 25 cm rectangular bag-like container. 150g of pork was cooked from the opening, and the opening was heat sealed. When retorting was performed at 120 ° C. for 25 minutes, the container surface had a smooth and beautiful appearance.
[0028]
[Example 2]
Was dry laminated unstretched polypropylene 25.mu. m inside the heat-resistant outer layer laminate prepared in Example 1 by using an aliphatic urethane adhesive, after further superimposed unstretched polypropylene 30.mu. m, 170 ° C. hot roll The laminated body for retort processing containers was prepared by thermocompression bonding. When the adhesive strength between the unstretched polypropylenes was measured on a small piece having a width of 15 mm, the adhesive strength was 120 g. A rectangular bag-shaped container of 20 cm × 25 cm was similarly prepared from the laminate for a retort processing container. The opening was filled with 150 g of cow tongue stew, and the opening was heat sealed. When the retort treatment was performed at 125 ° C. for 15 minutes, the container surface had a smooth and beautiful appearance.
[0029]
[Comparative Example 1]
Rectangular bags Example unstretched polypropylene 60 microns m dry lamination retorted container laminate was prepared using an aliphatic urethane adhesive 1 on the inside of the prepared heat-resistant outer layer laminate, similarly 20 cm × 25 cm A container was prepared. 150g of pork was cooked from the opening, and the opening was heat sealed. When the retort treatment was performed at 120 ° C. for 25 minutes, fine irregularities as seen in the outer shell of the cocoon were formed on the surface of the container, and the appearance was remarkably impaired.
[0030]
[Comparative Example 2]
Was dry laminated unstretched polypropylene 25.mu. m inside the remarkable made with heat-resistant outer layer laminates in Example 1 using the aliphatic urethane adhesive, after further superimposed unstretched polypropylene 30.mu. m, 200 ° C. heat Thermocompression bonding was conducted through a roll to prepare a retort processing device laminate. When the adhesive strength between the unstretched polypropylenes was measured for a small piece having a width of 15 mm, the adhesive strength was 1.5 kg. A rectangular bag-shaped container of 20 cm × 25 cm was similarly prepared from the laminate for a retort processing container. The opening was filled with 150 g of cow tongue stew, and the opening was heat sealed. When the retort treatment was performed at 125 ° C. for 15 minutes, fine irregularities such as those seen in the outer shell of the cocoon were formed on the surface of the container, and the appearance was remarkably impaired.
[0031]
【The invention's effect】
As described above, in a bag container for retort sterilization suitable for oil-based foods constituted by a laminate comprising a heat-resistant outer layer and a heat-resistant sealant layer, and the container film, the inner sealant layer has two or more layers. By adopting a non-adhesive, weakly-adhered, or partially-adhered laminated structure, the swelling and deformation of the sealant layer due to the oil and fat components released from the oil-based food during retort processing stops only in the innermost layer of the sealant, and the bag surface is beautiful. Can provide.

Claims (4)

A barrier layer is included between the heat-resistant outer layer and the heat-resistant sealant layer, including at least one heat-resistant outer layer and a heat-resistant sealant layer selected from polyethylene terephthalate, nylon, and stretched polypropylene. a laminate having, laminate is a laminate structure that is dry lamination except that it is heat-resistant sealant layer is two or more layers of non-adhesive, a weak bonding, or partially bonded constituting the innermost layer, A retort sterilization-compatible bag-like container for filling oil-based foods, wherein the laminated body and the heat-resistant sealant layers of the laminated body are completely adhered to each other at the seal portion around the container. The bag container for retort sterilization for oily food filling according to claim 1, wherein the barrier layer is an aluminum foil, an aluminum vapor deposited heat resistant resin layer, an ethylene vinyl alcohol copolymer or the like. The bag container for retort sterilization for oily food filling according to claim 1 or 2, further comprising a reinforcing layer for improving the piercing resistance such as nylon between the barrier layer and the heat resistant sealant layer of the laminate. 3. The bag container for retort sterilization for filling oily food according to claim 1, wherein the laminated structure is laminated by a dry laminating method except for lamination between heat-resistant sealant layers.