JPS6345305Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a lid material, and more particularly to a lid material mainly used for forming an easy-to-open molded lid for liquor containers.

Generally, sake cup packaging involves hot filling, so vacuum absorption is essential. Currently, in almost all cases, the vacuum absorbent part is molded with a lid to form the vacuum absorbent part. However, in this case, the lid material is thick because it is molded, and during heat sealing, it is difficult for the heat of the seal bar to be transmitted through the lid material to the sealing surface, and it is easy to cause uneven heat.
In extreme cases where the seal is unstable, a seal failure may occur where the seal is not formed locally, so-called seal failure.

Furthermore, there are almost no heat sealing layers with stable sealing strength, and there are currently no lidding materials for liquors provided with a sheet sealing layer that does not contain low molecular weight and has little odor.

From these points of view, it is desired to create an easy-to-open lid material for alcoholic beverages that uses a heat-sealing layer that maintains shape retention, reduces the thickness of the lid material, and has stable heat-sealability.

As a result of research to develop a molded lid for liquor containers that retains its shape, exhibits stable heat-sealability, stable and good ease of opening, and has oxygen barrier properties, the inventor found that the top layer A cohesive failure sealant layer consisting of a polybutylene terephthalate film as an intermediate layer, a polyvinylidene chloride coated unstretched nylon film and an unstretched polypropylene film as an intermediate layer, and a polyethylene-polypropylene blend polymer as the bottom layer, and the polyethylene-polypropylene blend polymer are heated. We have discovered that the above-mentioned molded lid for liquor containers can be obtained by using a lid material consisting of a coextruded two-layer film comprising a support layer made of a resin with good fusion properties, and based on this knowledge, we have developed this book. The idea has been completed.

That is, the gist of the present invention is a laminated material consisting of a polybutylene terephthalate film as the top layer, a polyvinylidene chloride coated unstretched nylon film as the intermediate layer, an unstretched polypropylene film, and a coextruded two-layer film as the bottom layer. The coextruded two-layer film is composed of two layers: a cohesive failure sealant layer made of a polyethylene-polypropylene blend polymer, and a support layer made of a resin with good heat fusion properties with the polyethylene-polypropylene blend polymer; This lid material is characterized by being laminated so that the side surface of the support layer faces toward the middle layer.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows a lid member 7 according to the present invention.

The lid material of the present invention is made by laminating a polybutylene terephthalate film 1 as the top layer, a polyvinylidene chloride coated unstretched nylon film 2 and an unstretched polypropylene film 3 as the middle layer, and a coextruded two-layer film 4 as the bottom layer. The coextruded two-layer film 4 has two layers: a cohesive failure sealant layer 6 made of a polyethylene-polypropylene blend polymer, and a support layer 5 made of a resin with good heat fusion properties with the polyethylene-polypropylene blend polymer. and are laminated so that the side surface of the support layer 5 faces the intermediate layers 2 and 3 side.

Therefore, in the present invention, the polybutylene terephthalate film 1 is laminated to impart properties such as moldability, heat resistance, and shape retention to the lid material, and its thickness is preferably 30 to 150μ, and 30μ or less. If it is 150μ or more, pinholes and holes will occur in the corners of the molded product, and the shape retention will be poor, making it impossible to maintain the shape of the lid.If it is 150μ or more, excessive heat will be generated during heat sealing. This is undesirable because it becomes difficult, tends to cause poor heat sealing, and increases costs.

Next, the polyvinylidene chloride coated unstretched nylon film 2 is laminated to provide oxygen barrier properties to the lid material, and is preferably 20 to 50 μm, and 20 μm
In the following cases, pinholes and perforations will occur at the corners during molding, which will eliminate the barrier effect, which is undesirable.If the thickness exceeds 50μ, nylon does not have good moldability, so the moldability of the entire lid material will deteriorate. This is not preferable because the corner portions cannot be formed sharply.

Next, the unstretched polypropylene film 3 is laminated to give rigidity and cushioning properties to the lid material, and its thickness is preferably 20 to 100μ, and if it is less than 20μ, there will be pin holes in the corners during molding. This is not preferable because it causes holes and there is no cushioning effect, and when it is more than 100μ, it is difficult to transmit heat during heat sealing, which tends to result in poor heat sealing, which is not preferable.

Next, as the coextruded two-layer film 4, a polyethylene-polypropylene blend polymer is extruded together with a resin that is easy to form into a film for the support layer and has good heat fusion properties with the polyethylene-polypropylene blend polymer, using a T-die method or an insulating film. A film formed by the frayon method can be used.

The thickness of the cohesive failure sealant layer made of polyethylene-polypropylene blend polymer is 3 to 3.
50μ is preferable, and 3μ or less is not preferable because the peel strength after heat fusion is below practical strength.
When it is more than 50 μm, it is not preferable because not only the cost increases but also the film forming property is extremely deteriorated.

In addition, the blend ratio of polyethylene and polypropylene is preferably 7:3 to 3:7, and when the amount of polyethylene increases and the blend ratio becomes 7:3 or more, cohesive failure does not occur and interfacial peeling occurs, and the heat seal strength is It is undesirable because it fluctuates depending on the temperature and is unstable. If the amount of polypropylene is too large and the blend ratio is less than 3:7, it is undesirable because complete fusion occurs and easy opening properties are lost.

Next, as the resin for the support layer 4, ethylene-α olefin copolymer, high density polyethylene, medium density polyethylene, low density polyethylene, polypropylene, etc. can be used, and the thickness is 20
~100μ is preferable, and if it is less than 20μ, cracks will occur in the support layer and normal opening will not be possible, delamination will occur between the unstretched polypropylene film and the support layer, and the film will tend to stick, so it is not preferable.
If it is 100μ or more, it is not preferable because heat is not easily transmitted during heat sealing and heat sealing is likely to be defective.

Next, in the present invention, along with the polyethylene-polypropylene blend polymer and the resin for the support layer, polypropylene, polyethylene, ethylene-α olefin copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate are added adjacent to the resin for the support layer. The support layer may be composed of two resin layers by extruding a resin such as a saponified copolymer, an ionomer resin, a polyamide, or a polyvinylidene chloride.

FIG. 2 shows another example 8 of the present invention.

This example of the present invention differs from the one shown in Figure 1 in that the stacking order of the polyvinylidene chloride coated unstretched nylon film 2 and the unstretched polypropylene film 3 is reversed.

The polybutylene terephthalate film 1, the polyvinylidene chloride coated unstretched nylon film 2, the unstretched polypropylene film 3, and the coextruded two-layer film 4 are laminated in the lamination order shown in FIG. 1 or 2, using an adhesive such as an isocyanate adhesive. The lid material of the present invention can be obtained by dry laminating using.

FIG. 3 shows an example of a molded lid formed using the lid material 7 of the present invention shown in FIG.

FIG. 4 shows a package sealed with the molded lid 9 shown in FIG. 3, and in the figure, 12 indicates the container body, and 13 indicates the contents such as alcohol. The reduced pressure absorbing convex portion 10 is drawn into the container and becomes substantially flat as the contents 13 filled in the container body 12 in a hot state cool down and the pressure inside the container is reduced.

FIG. 5 shows the package shown in FIG. 4 in an unsealed state.

When the opening tab 11 is pulled upward, the cohesive failure sealant layer 6 first breaks, and then peels off at the interface between the support layer 5 and the cohesive failure sealant layer 6, causing stringiness on the flange surface of the container body 12. , the package can be opened easily without causing any lint or the like.

As detailed above, according to the lid material of the present invention,
Not only can it provide a lid that can be easily opened with appropriate peel strength without causing stringiness or fuzzing on the flange surface of the container body, but also
The thickness of the lid material is such that the heat of the seal bar can be sufficiently transmitted to the sealing surface through the lid material, so it is possible to provide a lid body that does not cause sealing defects, and the sealant layer is formed by extrusion molding. The film is formed without using additives such as slip agents and antioxidants, which are undesirable from a food hygiene perspective.It exhibits stable peel strength and the sealant layer is suitable for the lid material. The sealant layer does not easily peel off from the base material, and the sealant layer does not contain any harmful additives, so it has the advantage of causing no problems in terms of food hygiene.

Next, the present invention will be specifically explained with reference to examples.

Examples Polybutylene terephthalate film 50μ, polyvinylidene chloride coated unstretched nylon 30μ, unstretched polypropylene 50μ, polyethylene 40μ (density
0.94, MI=2) and polyethylene-polypropylene blend polymer 20μ (polypropylene;
50wt% random copolymer, density 0.90, MI=6.0,
Coextruded films of 60μ of polyethylene (density 0.97, MI=8) were laminated in this order using an isocyanate adhesive, and the laminated material was vacuum formed to form a lid. This lid was then heat-sealed at 240°C to a polypropylene container filled with sake at 70°C. After cooling, there is no abnormality in the lid, and the lid can be opened in good condition.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an example of the lid material of the present invention, FIG. 2 is a cross-sectional view of another example of the lid material of the present invention, FIG. 3 is a cross-sectional view of an example of a formed lid made of the lid material of the present invention, and FIG.
FIG. 5 is a cross-sectional view of the package sealed with the molded lid shown in FIG. 3, and FIG. 6 is a cross-sectional view of the package shown in FIG. 4 after it has been opened. 1...polybutylene terephthalate film, 2
... polyvinylidene chloride coated unstretched nylon film, 3... unstretched polypropylene film, 4...
Coextruded two-layer film, 5...support layer, 6...cohesively failable sealant layer.

Claims (1)

[Claims for Utility Model Registration] (1) Consisting of a polybutylene terephthalate film as the top layer, a polyvinylidene chloride coated unstretched nylon film and an unstretched polypropylene film as the middle layer, and a coextruded two-layer film as the bottom layer. The coextruded two-layer film is a laminated material, and the coextruded two-layer film is composed of two layers: a cohesive failure sealant layer made of a polyethylene-polypropylene blend polymer, and a support layer made of a resin having good heat fusion properties with the polyethylene-polypropylene blend polymer. , and are laminated so that the side surface of the support layer faces toward the middle layer. (2) The lid material according to claim 1, wherein the support layer is made of an ethylene-α olefin copolymer. (3) The lid material according to claim 1, wherein the support layer is made of high-density polyethylene. (4) The lid material according to claim 1, wherein the support layer is made of medium density polyethylene. (5) The lid material according to claim 1, wherein the support layer is made of low-density polyethylene. (6) The thickness of the polybutylene terephthalate film is 30 to 150μ, the thickness of the polyvinylidene chloride coated unstretched nylon film is 20 to 50μ, and the thickness of the unstretched polypropylene film is
The thickness of the support layer is 20 to 100μ, and the thickness of the cohesive failure sealant layer is 3 to 100μ.
The lid material according to claims 1 to 5 of the utility model registration claim, characterized in that it has a thickness of 50μ.