JPS6049432B2 - Easy-peel film manufacturing method - Google Patents

Description

Detailed Description of the Invention The present invention relates to a method for producing an easy-peel film having an olefinic resin layer and an easy-peelable sealing layer. The present invention relates to a manufacturing method characterized by a coextrusion method that enables a smooth film surface to be obtained.

The performance required of packaging is that it protects the contents during the manufacturing and distribution stages, and that the contents are easy to remove.In other words, it is required to have the opposite functions of sealing and easy peeling. However, I have started to
Until now, in the case of a package whose seal layer was an olefin resin layer such as PP or PE, a resin of the same type was selected as the other seal layer. There was no peeling property.

For this reason, recently, when the sealing layer is an olefin resin layer, in order to make the package easy to peel, the sealing layer is made of a blended resin layer made by blending specific different resins at a certain ratio. However, when these were coextruded alone, various problems were corrected. For example, PE or EVA 70-95% by weight and polybutene 15-95% by weight.
When PP is a sealing layer in a different resin blend resin layer in which 30% by weight is blended, the other sealing layer is -P.
By using a different resin layer that is a blend of 20 to 80% P by weight and 20 to 8% PE by weight, the package can be sealed and easily peeled, but the thickness of these sealing layers should be about 50 μm. Generally, the thickness is 50μ or less because it functions as a sealing layer.
When a different resin blend resin layer, which is a blend of different resins as described above, is extruded alone, the resins do not have good compatibility with each other, so the elongation during melting is poor. It is easy to tear and cannot be produced continuously, and the resulting film has poor compatibility with each other's resins, resulting in rough skin on the surface of the film. In this case, it became foamed and could not be used as a film. For this reason, the sealing layer is a blend of different resins as described above, which is sealed with an olefin sealing layer and can be easily peeled while having sealing properties, and these are continuously produced and can be obtained without causing rough skin. As a result of various studies on manufacturing methods, we found that a different resin blend resin layer made of PE or EVA blended with polybutene-1, which can be easily peeled by being sealed with a PE or EVA sealing layer, or a resin layer that is sealed with a PP sealing layer and can be easily peeled. By simultaneously coextruding a different resin blend resin layer blended with possible PPICPE in combination with a processability improving resin layer to improve the extrusion processability of these resin layers, the different resin Prene F resin layer can be It was possible to obtain a composite film 1 that could be produced continuously without breaking during withdrawal after exiting, and was coextruded in a composite state without roughening on the surface. In this way, a different resin blend resin layer made by blending PE or EVA with polybutene-1 or PP. When the resin layer of a blend of different resins blended with PE is extruded alone, it is 50%
It was difficult to obtain a film as thin as μ, but by combining these different resin blend resin layers and a resin layer for improving processability as in the present invention, for example, PP/(PP+H
When coextruding a combination such as a DPE blend) resin layer or a (PE + polybutene-1 blend)/ionomer/6Ny resin layer, the different resin blend resin layer loses its function due to the processability of PP, 6Ny, etc. It has become possible to easily produce very thin films of 50 μm or less without any problems.

The film obtained by the production method of the present invention can be used for the main body of the container and for the filler material, and the thickness is sufficient as a sealing layer at 50 μm or less, so it is easy to process, especially when used for the main body of the container. The improved resin layer preferably has good thermoformability. In addition, PE is used as the workability improving resin layer.
NEVAl Aiomar, PP. sNy. ．． It is a single layer of saponified EVA or PS, or a composite layer made of a combination of these, and an adhesive layer is provided between these resin layers and the different resin blend resin layer, if necessary. Next, examples will be described. Examples 1 and 2 are cases in which a different resin blend resin layer is used as a sealing layer for the container body, and Example 3 is a case in which a different resin blend resin layer is used as a sealing layer in the lid material. , each of which is a package that can be easily peeled while having an olefin resin layer that has sealing properties. Example 1 A 500 μm PP sheet was thermoformed to form a cup container, and a lid material was sealed to the cup container to make it easier to open and peel the package.

In addition, when PP is used as a sealing layer, it has been found through experiments that by using a different resin blend resin layer in which PP and PE are blended as the other sealing layer, sealing performance can be improved and easy peeling can be achieved.

(Conventional method) When a blend of different resins (PP6O weight% + HDPE4O weight%) was extruded using a 9-hour extruder with L/D28, when the film was less than 200 μm, the film broke when drawn down and could not be removed. By adjusting the extrusion conditions and the lip clearance of the die, it became possible to extrude up to 150μ, but it was not possible to obtain the desired film of about 50μ by single extrusion of the above-mentioned different resin blend resin layer.

(Method of the present invention) Therefore, a 90rf1In extruder with L/D28 and
Using a coextrusion device consisting of a 65Tf0n extruder and a two-layer manifold die, 1PP (MlO.
, 2 (PP6O weight % + 1 IDPE 4 heel weight %) in a two-layer film of 50μ of different resin blend resin was coextruded, it could be continuously produced without any problems, and in terms of performance it was almost the same as a single PP sheet.

This sheet is thermoformed into a cup shape with the (PP+HDPE) blend resin layer serving as the sealing surface to form the container body.
Add to this a lid material made of PP/PET, with the PP surface as a sealing layer, and the sealing pressure between the sealing layers is 2k9/C! When sealed under the sealing conditions of t1 sealing temperature of 180℃ and sealing time of 3 seconds, the sealing strength was 1100V/
15wn, it was easy to peel by hand. Example 2 When the sealing layer is made of PE, in order to be able to easily peel it while having sealing properties, it is necessary to use a different resin blend resin layer, which is a blend of PE and polybutene-1, as the sealing layer on the other side. Experimental results have shown that a package that can be easily peeled can be obtained.

(Conventional method) Using the same extruder as in Example 1, a blend of different resins (85% by weight of PE + 115% by weight of polybutene) was used.
When a 0μ film was extruded, the film could be produced continuously, but the surface was rough.

For this reason, when this film was dry-laminated with a K-coated 15μ polyester film, the laminate contained air bubbles in the recesses over the entire surface of the film, making it impossible to commercialize the film. (Method of the present invention) Therefore, using a coextrusion device consisting of an L/D289-extruder, a L/D285O sequential extruder, an L/D2865mln extruder, and a three-layer manifold tie, 1 (LDPE85
When a composite film having a three-layer structure consisting of a different resin blend resin layer (70μ by weight, 10μ by weight of 2-ionomer, and 50μ by weight of 36Ny) was extruded, there was no foaming and the film had an attractive appearance.

This film is deep-drawn to form a container body with the different resin blend resin layer serving as a sealing layer, and a lid material made of K-coated polyester/PE with a sealing layer of PE is applied to this film at 140'Cl2kg/cl for 2 seconds. When the package was sealed under the following sealing conditions, the package had no foaming in appearance and had good sealing properties, but the seal strength was as low as 600y/15 and could be easily peeled. Example 3 A lid material that could be easily peeled and sealed with a PP container with good transparency was investigated.

Lid materials are usually made by extruding a single layer of various films and dry laminating them into a composite. In addition, the lid material is generally divided into a heat-resistant layer and a sealing layer.The heat-resistant layer is for the purpose of preventing the film from adhering to the heating plate during sealing, and when PP is the sealing layer, the heat-resistant layer is As the layer, a PET or Ny layer is used. (Conventional method) (PP6O weight% (MI2.O) + HDPE4O weight%
When a different resin blend resin (MI7.
When Ny was dry laminated, the resulting film contained many bubbles, which caused problems in practical use.

(Method of the present invention) Therefore, in the three-layer extruder used in Example 2, 16Ny (thickness composition ratio 30%), modified PP with two adhesive layers
(5%), 3. When we co-extruded a 3-layer film made of different resin blend resins (65%) of (PP + HDPE) examined using the conventional method, we were able to continuously extrude films up to 30p without bubbles.

Claims (1)

[Claims] 1. A method for producing an easy-peel film by co-extruding an olefin resin layer, an easy-peelable different resin blend resin layer, and a processability-improving resin layer. 2. A method for producing an easy-peel film, in which the different resin blend resin layer according to claim 1 is obtained by coextruding PE or EVA blended with polybutene-1. 3. A method for producing an easy-peel film by blending and co-extruding the different resin blend resin layers PP and PE according to claim 1. 4. The processability improving resin layer according to claim 1 is made of P.
A method for producing an easy-peel film formed by coextruding a single layer of E, EVA, ioimer, PP, Ny, saponified EVA, or PS, or a composite layer of a combination thereof. 5. A method for producing an easy peel film, wherein the blend ratio of the different resin blend resins according to claim 2 is 70 to 95% by weight of PE or EVA and 15 to 30% by weight of polybutene. 6. A method for producing an easy peel film according to claim 3, wherein the resin blend ratio is 20 to 80% by weight of PP and 20 to 80% by weight of PE.