JPH0110202Y2 - - Google Patents

Description

[Detailed explanation of the idea]

This invention relates to a lid material for a container. As a lid material that has barrier properties and is hard to curl and wrinkle, for example, a biaxially stretched nylon film is laminated on both sides of a barrier film with an adhesive, and an adhesive is applied to the outer surface of one of the nylon films. A structure in which a sealant layer is provided therebetween has been devised. However, such a lid material has a seven-layer structure including the adhesive layer, which is disadvantageous in terms of cost. Therefore, the object of this invention is to provide an inexpensive lid material with a simplified structure while satisfying the required performance. In order to solve the above problems, according to this invention,
2 with a thickness of 12 to 40μ on one side of the barrier film.
Axially stretched nylon films are laminated, a sealant layer is provided on the outer surface of this laminate, and the thickness of the barrier film is 1.25 to 0.5 that of the nylon film.
It was doubled. With this configuration, a laminate of at most five layers is sufficient, making it possible to reduce costs, and by selecting a thickness that takes advantage of the rigidity of the nylon film, curls and wrinkles can be prevented. be. Embodiments of this invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, the lid material 1 has a biaxially stretched nylon film 4 laminated on one side of a barrier film 2 via an adhesive 3, and an adhesive 5 on the other side.
A sealant layer 6 is provided therebetween. As the barrier film 4, a film having barrier properties itself such as polyvinylidene chloride, polyacrylonitrile, ethylene vinyl alcohol copolymer, polyvinyl alcohol, nylon with barrier properties, etc. is used. Further, the sealant layer 6 may be made of any heat-sealable resin, but for example, if the container body is made of polypropylene, a blend of polyethylene and polypropylene may be used for better unsealability. Note that this sealant layer 6 can also be provided directly without intervening the adhesive 5. The sealant layer 6 can also be provided on the outer surface of the nylon film 4. That is, as shown in FIG. 2, a barrier film 2 and a biaxially stretched nylon film 4 are laminated with an adhesive 3, and a sealant layer 6 is provided on the outer surface of the nylon film 4. In the lid material 1 as described above, the thickness of the barrier film 2 is 1.25 times the thickness of the nylon film 4.
Must be ~0.5x. If the thickness is outside this range, curling will occur during manufacture of the lid material 1, and problems such as curling up will occur when the lid material 1 is opened after retort sterilization. Furthermore, the thickness of the nylon film 4 is approximately 12
~40μ is appropriate. If it is less than 12μ, the mechanical strength of the lid material 1 will be too weak and may be damaged during transport, etc. If it is 40μ, if the container body is not strong, the lid material will shrink due to retort sterilization and the container will be damaged. This may result in deformation of the product, which may result in loss of commercial value. Hereinafter, more detailed examples will be described together with comparative examples. "Examples 1 to 5 and Comparative Examples 1 and 2" A biaxially stretched nylon film and a vinylidene chloride film (barrier film) were laminated with the thickness and thickness ratio shown in the following table, and the outer surface of the vinylidene chloride film was used as a sealant. A lid material was prepared that was laminated with a 28μ thick film made of a blend of polypropylene and polyethylene.

【table】

[Table] First, when the finished lid materials were observed, the lid materials of Examples 1 to 5 were flat and had no curls, but the lid materials of Comparative Example 1 were found to have curls. Next, each of the above lid materials was heat-sealed to a polypropylene molded container (thickness 0.8 mm) filled with water.
These were retort sterilized at 121°C for 30 minutes. The containers using the lids of Examples 1 to 5 did not burst during retort sterilization, and the lids appeared to be under tension and the containers did not deform. Furthermore, when the bag was opened, the lid could be easily peeled off, and there was little roll-up. On the other hand, Comparative Example 1 rolled up when opened,
In addition, in Comparative Example 2, the container was deformed during the sterilization process, resulting in an unfavorable appearance.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of the lid material of this invention. DESCRIPTION OF SYMBOLS 1... Lid material, 2... Barrier film, 3... Adhesive, 4... Biaxially stretched nylon film, 5... Adhesive, 6... Sealant layer.

Claims (1)

[Scope of utility model registration request] Film and thickness that have barrier properties themselves
A sealant layer is provided on one side of a laminate of biaxially stretched nylon films of 12 to 40μ, and the thickness of the barrier film is 1.25 to 0.5 of the thickness of the nylon film.
A lid material for a container characterized by being doubled.