JPH0322293B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a tube-shaped release film, and more specifically, a method for manufacturing a tube-shaped release film.
The present invention relates to a method for manufacturing a release film, in which a release layer made of silicone resin is integrally formed on at least the inner surface of both the inner and outer surfaces of the release film.

[Conventional technology]

Conventionally, the method of packaging sticky substances such as asphalt, rubber, hot melt, and candy involves wrapping these sticky substances in release paper and packaging them in a cardboard box, which has been given releasability to the inner surface itself. There are two methods: using a cardboard box, and using a stack of paper bags in which only the innermost part that comes into direct contact with the sticky substance is made of release paper, but both of these methods are time-consuming and time-consuming to package. , which is fundamentally unsuitable for mass production methods in which products are continuously filled and packaged while being manufactured.

For this reason, a tube-shaped release film with a release layer formed on the inner surface is desired. Conventionally, such a release film is a sheet-like release film with a release layer of silicone resin formed on one side. It is known that the tube is formed into a cylindrical shape so as to have an inner surface (for example, Japanese Patent Application Laid-Open No. 48-31276).

[Problem that the invention seeks to solve]

However, this method of manufacturing a tube-shaped release film requires a lot of effort and effort, as it requires forming a release film sheet on which a release layer of silicone resin is formed, and then forming this sheet into a cylinder shape. When forming a cylindrical shape, both ends of the sheet-like release film in the width direction must be joined to each other, but since the silicone resin release layer, which inherently has poor bonding properties, is on the inner surface, a special method is required for joining. Moreover, since the joint portion is formed in a band shape, problems may arise in terms of usability.

The present invention has been made in view of the above circumstances, and is a tube-shaped tube without a band-shaped joint, which is formed by integrally laminating a release layer made of silicone resin on at least the inner surface of both the inner and outer surfaces of a tube body made of thermoplastic synthetic resin. It is an object of the present invention to provide a method for manufacturing a tube-shaped release film, which can easily and reliably produce the release film while adapting to a continuous mass production system.

[Means for solving problems]

The present invention adopts the following two methods in order to obtain a tube-shaped release film having a release layer on the inner surface that achieves the above object.

(1) A mixture containing a thermoplastic synthetic resin and a silicone release agent that is cured by radiation irradiation is heated and melted and extruded into a cylindrical shape to form a cylindrical extruded film, and blooming is applied to both the inside and outside of this extruded film. After forming a release agent layer of the silicone release agent on the surface, the extruded film is irradiated with radiation to cure the release agent layer to form a release layer made of a thin film of silicone resin.

(2) The thermoplastic synthetic resin for the base material is obtained by heating and melting a mixture containing a thermoplastic synthetic resin and a silicone-based release agent that hardens by radiation irradiation, and heating and melting the thermoplastic synthetic resin for the base material. The mixture is extruded into a cylindrical shape to form a laminated film in which the base material made of the thermoplastic synthetic resin for the base material is laminated and integrated on the outer surface of the cylindrical extruded film made of the mixture, and this extrusion is performed by blooming. After forming a release agent layer of the silicone release agent on the inner surface of the film, the composite film is irradiated with radiation to cure the release agent layer to form a release layer made of a thin film of silicone resin.

These methods can be used to continuously form a thermoplastic synthetic resin tube body B made of polyethylene, polypropylene, etc., as shown in Figure 2. Peeling layers C and C made of silicone resin on both the inside and outside surfaces
A release film A formed by integrally forming
In the method (2), a release layer C made of silicone resin is integrally formed on the inner surface of a thermoplastic synthetic resin tube body B made of polyethylene, polypropylene, etc. as shown in FIG. At the same time, it is possible to produce a laminated film A in which the thermoplastic synthetic resin base material D is laminated on the outer surface of the tube body B.

[Effect]

As described above, the manufacturing method of the present invention includes forming a cylindrical extruded film by heating and melting a mixture containing a thermoplastic synthetic resin and a silicone release agent that hardens by radiation irradiation, and extruding it into a cylindrical shape. , by forming a release agent layer of the silicone release agent on at least the inner surface of this extruded film by blooming, and then irradiating with radiation to harden the release agent layer to form a release layer made of a thin film of silicone resin. A tube-shaped release film having a release layer integrally formed on at least the inner surface can be easily and reliably produced.

In other words, it is extremely difficult to apply a release agent to the inner surface of the tube using a conventional coater and then dry and harden it with hot air.
According to the method of the present invention, a uniform release agent layer can be easily formed on the inner and outer surfaces of an extruded film. The extruded film produced in this way is then irradiated with radiation to cure the release agent, but unlike the conventional method of heating and curing with hot air, this method requires a smaller overall device. Moreover, it is simple, and unlike conventional methods, the processing speed is not limited by the length of the oven, and the production speed of the release film is high.

The release film produced in this way has particularly good adhesion between the cured silicone layer and the extruded film layer because it has been irradiated with radiation. There is no inconvenience such as falling off.

This release film is suitable for packaging adhesive materials, and when packaging highly adhesive materials such as asphalt, hot melt, rubber, etc., the contents will not stick to the release film, and (1) The release film obtained by this method has a release layer formed on the outer surface and also has release force, so even if the release film is filled with the contents at high temperature, packaged, and deposited, this The outer surfaces of the package are not fused to each other, and furthermore, since the release film has a peeling force on the outer surface, the outer surface is less likely to become dirty. Therefore, when products, etc. are packaged using this release film, the aesthetic appearance of the packaging can be maintained for a long period of time.

In addition, according to the coextrusion inflation method (2), it has the same advantages as the method for manufacturing double-sided release films using radiation irradiation, and since the base material is laminated on the outer surface of the release film, this base material is laminated on the outer surface of the release film. By appropriately selecting the material, a release film having various desirable properties can be produced, and this release film is suitable as a tube-shaped packaging material.
For example, when packaging contents using this release film, the contents do not adhere to the inner surface of the packaging material, and there is no release layer on the outer surface, so printing, printing, etc. can be arbitrarily performed on the surface. It is.

Embodiments of the present invention will be described below with reference to the drawings.

[First Example] FIG. 1 shows polyethylene as shown in FIG.
Flexible synthetic resin tube body B such as polypropyline
a release layer C made of silicone resin on both the inner and outer surfaces of the
This figure shows an example of an apparatus for continuously manufacturing release film A having C by an inflation method.

That is, 1 in FIG. 1 is an extruder equipped with a hopper 2 and a circular die 3. A uniform mixture 4 of a thermoplastic synthetic resin and a silicone release agent that is hardened by radiation irradiation is charged into the hopper 2 . Thermoplastic synthetic resins include low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, ethylene and vinyl acetate,
Copolymers with acrylic acid, methacrylic acid, etc. are preferred. Also, as a release agent, it has a low viscosity (50~
An organopolysiloxane having a mercapto group of 500 cps (for example, a polysiloxane stripping agent disclosed in Japanese Patent Publication No. 54-6512) can be used.

The homogeneous mixture 4 of thermoplastic synthetic resin and release agent in the hopper 2 is heated and melted in the extruder 1, and then sent to the circular die 3, where it is extruded upward in a cylindrical shape, and air is forced inside. The extruded film 5 is formed by being blown and expanded to a predetermined size. In this case, after the extruded film 5 is extruded from the die 3, it naturally starts blooming within a short time and deposits a silicone release agent on the surface of the extruded film 5, so that both the inner and outer surfaces of the extruded film 5 are Covered with a uniform layer of release agent. Next, the extruded film 5 whose both surfaces are coated with the release agent layer travels in the direction of arrow Z in the figure and reaches the radiation irradiation device 6. This radiation irradiation device 6 irradiates radiation, and when the extruded film 5 passes through this device, it is irradiated with radiation of 10 megarads or less to harden the release agent layer, thereby forming a thin film of silicone resin on both the inside and outside surfaces. A tube-shaped release film A having a release layer C consisting of the following is continuously produced and wound onto a winding roll 7. In this case, the radiation dose is preferably 10 megarads or less; irradiation with a dose exceeding this is not preferred because it causes deterioration of the extruded film.

The release film obtained by this method is an extruded film (tube body made of thermoplastic synthetic resin) with release layers of silicone resin integrally formed on both the inner and outer surfaces. When packaging highly adhesive materials such as rubber, the contents do not stick to the release film, and the outer surface also has peeling strength, so the contents are filled in the release film at high temperature, packaged, and deposited. The outer surfaces of the package will not fuse to each other even if the package is left open. Furthermore, since this release film also has release force on the outer surface, the outer surface is less likely to become dirty. Therefore, when products, etc. are packaged using this release film, the aesthetic appearance of the packaging can be maintained for a long period of time.

[Second Example] FIG. 3 shows polyethylene as shown in FIG.
Flexible synthetic resin tube body B such as polypropyline
An apparatus for continuously producing a release film A by a coextrusion inflation method, in which a release layer C made of silicone resin is formed on the inner surface of the tube body B, and a base material D made of thermoplastic synthetic resin is laminated on the outer surface of the tube body B. This is an example.

That is, in FIG. 3, 1 and 1' are extruders each connected to a circular die 3 for coextrusion, and a hopper 2 of the extruder 1 is filled with a uniform thermoplastic synthetic resin and a silicone release agent that is cured by radiation. A thermoplastic synthetic resin 4' for the base material, such as polyethylene, polypropylene or a copolymer thereof, polyvinyl chloride, polyamide, etc., is charged into the hopper 2' of the extruder 1'. The heated melts of these resins are sent to a coextrusion circular die 3' by extruders 1 and 1', where they are concentrically extruded to form an extruded film and a base material, and the release agent is bloomed. Before the extruded film is deposited on the surface of the extruded film, the extruded film and the base material are laminated and integrated with the base material on the outside, and blow-up is carried out to form a tube-shaped film having a release agent layer deposited by blooming on the inner surface of the extruded film. A laminated film 5' is obtained. Next, the obtained laminated film 5' was led to a radiation irradiation device 6, where it was irradiated with radiation of 10 megarads or less to harden the release agent on the laminated film and form a release layer only on the inner surface. A tube-shaped release film A is obtained.

The release film obtained in this way is
As shown in the figure, a resin layer C made of silicone resin, a tube body B, and a base material D are sequentially laminated concentrically from the innermost layer to the outermost layer, and this is a release film that has peeling force only on the inner surface. be.
This release film is preferable as a tube-shaped packaging material. For example, when packaging contents using this release film, the contents do not adhere to the inner surface of the packaging material, and there is no release layer on the outer surface. , printing, printing, etc. can be arbitrarily performed on its surface.

In the production of the release film in the above example, the extruded film was irradiated with radiation while being continuously moved, but the present invention is not limited to this. The extruded film may be irradiated with radiation such as gamma rays and X-rays while it is in a stretched state, and various other modifications may be made without departing from the gist of the present invention.

〔Effect of the invention〕

According to the present invention, it is possible to easily, reliably, and continuously manufacture a release tube in which a release layer made of silicone resin is integrally formed on at least the inner surface of both the inner and outer surfaces of a thermoplastic synthetic resin tube body. In addition, due to its special structure, the release film obtained can be applied to various uses, for example, when a release film with release layers on both sides is used for packaging, it is necessary to ensure that the contents stick to the inner surface of the package. Furthermore, when using a release film with a release layer formed only on the inner surface of the package as a packaging material, it is possible to prevent the packaging from becoming dirty and effectively prevent the packages from sticking to each other. In addition to reliably preventing the package from sticking to the package, it is also possible to easily print on the outer surface of the package.

Furthermore, since this release film is tube-shaped, it can be used to fill the tube with adhesive material and can be easily packaged by clipping, bundling, etc., and can be used as a packaging material in continuous filling production systems. It is useful as a. Furthermore, this release film has various advantages such as being able to be made into a wider release film by cutting in the axial direction.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view showing an example of an apparatus for manufacturing a release film having release layers on both the inner and outer surfaces;
The figure is a radial cross-sectional view of a release film obtained by the apparatus shown in FIG. 1, FIG. FIG. 4 is a radial cross-sectional view of a release film obtained by the apparatus of FIG. 3; A...Peelable film, B...tube body, C...
...Peeling layer, D...Base material, 1...Extruder, 3...
Circular die, 6... Radiation irradiation device.

Claims (1)

[Claims] 1. A mixture containing a thermoplastic synthetic resin and a silicone release agent that hardens by radiation irradiation is heated and melted and extruded into a cylindrical shape to form a cylindrical extruded film, and the extruded film is extruded by blooming. After forming a release agent layer of the silicone release agent on both the inner and outer surfaces of the film, the extruded film is irradiated with radiation to harden the release agent layer to form a release layer made of a thin film of silicone resin. A method for producing a tubular release film having a release layer on the inner surface. 2. Heat and melt a mixture containing a thermoplastic synthetic resin and a silicone release agent that hardens by radiation irradiation, and heat-melt a thermoplastic synthetic resin for the base material, with the thermoplastic synthetic resin for the base material on the outside. By extruding the mixture into a cylindrical shape, a laminated film is formed in which the base material made of the thermoplastic synthetic resin for the base material is laminated and integrated on the outer surface of the cylindrical extruded film made of the mixture. After forming a release agent layer of the silicone-based release agent on the inner surface, the composite film is irradiated with radiation to harden the release agent layer to form a release layer made of a thin film of silicone resin. A method for producing a tubular release film having a release layer.