JPS6285930A - Manufacture of peeling film - Google Patents

Abstract

PURPOSE:To enable simple, secure, and mass-productive manufacture of tubular peeling films free of jointing part in band form which are laminated with a peeling layer of silicone resin on its inner surface, by forming the peeling agent layer of silicone peeling agent on both inner and outer surfaces of an extrusion film by blooming, and by forming the peeling layer by irradiation with radiation. CONSTITUTION:In a hopper 2, a uniform mixture 4 of a thermoplastic synthetic resin and a silicone peeling agent which is hardened on the irradiation with an ultraviolet light is introduced. After an extrusion film 5 is extruded from a die 3, blooming occurs naturally in a short time and the silicone peeling agent separate out on the surface of the extrusion film 5, thus both inner and outer surfaces of the extrusion film 5 are covered by a uniform layer of the peeling agent. Then a radiation is directed out of a radiation irradiating apparatus 6, and while the extrusion film 5 is transmitted through the inside, it is irradiated with radiation less than 10 Mega rad., whereby the peeling agent layer is hardened. A tubular peeling film A having peeling layer C made of the thin layer of silicone resin on both inner and outer surfaces is continuously prepared and wound up on a winding roll 7.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a tubular release film,
More specifically, the present invention relates to a method for manufacturing a release film formed in a tube shape, 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, methods for packaging sticky substances such as asphalt, rubber, hot melt, and candy include wrapping these sticky substances in release paper and packaging them in a cardboard box.
There are two methods: using a cardboard box with release properties on the inner surface itself, and using a stack of paper bags in which only the innermost part that comes into direct contact with the adhesive is made of release paper. All of these require time and effort to package, and are 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, but conventionally, such a release film has a sheet-like release film with a silicone resin release layer formed on the negative side. It is known that the inner surface is formed into a cylindrical shape (for example, Japanese Patent Laid-Open No. 48-3
1276).

[Problem that the invention seeks to solve]

However, this method of manufacturing a tubular release film requires a lot of effort and effort, as it requires forming a sheet of release film 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.1 Since the release layer of silicone resin, which has essentially 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 producing a tubular release film that can easily and reliably produce a release film while adapting to a continuous mass production system.

[Means for solving problems]

The present invention employs the following two methods in order to obtain a tubular 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 hardens by radiation irradiation is heated and melted and extruded into a cylindrical shape to form a cylindrical extruded film,
After forming a release agent layer of the silicone release agent on both the inner and outer surfaces of this extruded film by blooming, the extrusion film is irradiated with radiation to harden the release agent layer to form a release layer made of a thin film of silicone resin. How to form.

(2) A mixture containing a thermoplastic synthetic resin and a silicone release agent that hardens by radiation irradiation is heated and melted, and a thermoplastic synthetic resin for the base material is heated and melted. 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 by extruding the mixture so that it is on the outside, and this extrusion is performed by blooming. A method of forming a release layer of the silicone release agent on the inner surface of the film, and then irradiating the composite film with radiation to harden the release layer to form a release layer made of a thin film of silicone resin.

In these methods, the formation can be performed continuously by the inflation method, but in particular, the method (1) is suitable for the second method.
A release film A can be produced in which release layers C2C made of silicone resin are integrally formed on both the inner and outer surfaces of a thermoplastic synthetic resin tube body B made of polyethylene, polypropylene, etc. as shown in the figure, (2) In this method, as shown in FIG. 4, a peeling layer C made of silicone resin is integrally formed on the inner surface of a thermoplastic synthetic resin tube B made of polyethylene, polypropylene, etc., and the outer surface of the tube B is A release film A can be produced in which a thermoplastic synthetic resin base material is laminated on the base material.

[Effect]

As described above, the manufacturing method of the present invention includes forming a cylindrical extruded film by extruding a mixture containing a thermoplastic synthetic resin and a silicone release agent cured by radiation irradiation into a cylindrical shape by heating and melting the mixture. After forming a release agent layer of the silicone release agent on at least the inner surface of this extruded film by blooming, the release agent layer was cured by irradiation with radiation to form a release layer made of a thin film of silicone resin. By doing so, it is possible to easily and reliably produce a tubular release film in which a release layer is integrally formed at least on the inner surface.

In other words, the conventional method of applying a release agent to the inner surface of the tube using a conitor, etc., and then drying and curing it with hot air is extremely difficult. A release agent layer can be formed on the inner and outer surfaces of the extruded lumen. 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 the above method has a release layer formed on the outer surface as well, and the outer surface also has release force. Therefore, even if the contents are filled in the release film at high temperature and packaged, and the contents are accumulated, the packaging will not work. The outer surfaces of the object do not fuse together, and furthermore, the outer surface of this release film also has a peeling force, so the outer surface is less likely to get 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 producing a double-sided release film using radiation irradiation, and since the base material is laminated on the outer surface of the release film, this base material can be used. By appropriately selecting one, a release film having various desirable properties can be produced, and this release film is preferable as a tube-shaped packaging material.For example, when packaging contents using this release film, Since the contents do not adhere to the inner surface of the packaging material and there is no peeling layer on the outer surface, printing, printing, etc. can be arbitrarily performed on the surface.

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

[First Example] FIG. 1 shows a release film A having a release layer C2C made of silicone resin on both the inner and outer surfaces of a flexible synthetic resin tube body B made of polyethylene, polypropylene, etc. as shown in FIG. This figure shows an example of an apparatus for continuous production.

That is, 1 in Fig. 1 indicates the hopper 2 and the circular die 3.
It is an extruder equipped with A homogeneous mixture 4 of a thermoplastic synthetic resin and a silicone release agent that is cured by radiation irradiation is charged into the hopper 2 . Preferred thermoplastic synthetic resins include low-density polyethylene, medium-density polyethylene, high-density polyethylene, polypropylene, and copolymers of ethylene with vinyl acetate, acrylic acid, methacrylic acid, and the like. In addition, as a release agent, it has a low viscosity (50 to 500
An organopolysiloxane having a mercapto group (for example, a polysiloxane stripping agent disclosed in Japanese Patent Publication No. 54-6512) can be used.

After the homogeneous mixture 4 of thermoplastic synthetic resin and release agent in the hopper 2 is heated and melted in the extruder 1.

The film is sent to the circular die 3, where it is extruded upward into a cylindrical shape, and air is blown into the interior to expand it to a predetermined size, thereby forming an extruded film 5. In this case, after the extruded film 5 is extruded from the die 3, it starts blooming naturally 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 tubular 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 at high temperatures in the release film, packaged, and deposited. The outer surfaces of this package will not fuse together even if the outer surface of the package is kept on the product.Furthermore, the outer surface of this release film also has peeling force, so the outer surface is difficult to stain. When packaged, the aesthetic appearance of the packaging can be maintained for a long period of time.

[Second Embodiment] FIG. 3 shows that a release layer C made of silicone resin is formed on the inner surface of a flexible synthetic resin tube B made of polyethylene, polypropylene, etc. as shown in FIG. This figure shows an example of an apparatus for continuously manufacturing a release film A in which a base material made of thermoplastic synthetic resin is laminated on a base material made of a thermoplastic synthetic resin by a coextrusion inflation method.

That is, in FIG. 3, 1 and 1' are extruders connected to a circular die 3 for coextrusion, and the inside of the hopper 2 of the extruder 1 contains a thermoplastic synthetic resin and a silicone release agent that is cured by radiation. In addition, 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 each extruded by 1°1'
is sent to the coextrusion circular die 3', where it is concentrically extruded to form an extruded film and a base material, and the release agent is precipitated on the surface of the extruded film by blooming. The film and the base material are laminated and integrated with the base material on the outside, and blow-up is performed to obtain a tubular laminated film 5' having a release agent layer deposited by blooming on the inner surface of the extruded film. The laminated film 5' is led to a radiation irradiation device 6, where it is irradiated with radiation of 10 megarads or less to harden the release agent on the laminated film, forming a tube-shaped release film with a release layer formed only on the inner surface. This is what gets you an A.

The release film thus obtained has a release layer C made of silicone resin, a tube body B, and a base material laminated concentrically in order from the innermost layer to the outermost layer, as shown in Figure 4. , this is a release film that has release force only on the inner surface.

This release film is preferable as a tube-shaped packaging material.1 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 run; however, the present invention is not limited to this. The extruded film may be irradiated with radiation such as gamma rays and
Various modifications may be made without departing from the gist of the invention by others.

〔Effect of the invention〕

According to the present invention, it is possible to simply, reliably, and continuously produce 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. At the same time, due to its special structure, the resulting release film can be applied to various uses.1 For example, when a release film with release layers on both sides is used for packaging, it is ensured that the contents will 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. - It is possible to reliably prevent the package from sticking to the package, and it is also possible to easily print on the outer surface of the package.

Furthermore, since this release film is in the form of a tube, it can be used to fill the tube with adhesive materials and can be easily packed using 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 can also be made into a wide release film by cutting it in the axial direction.
It has various advantages.

[Brief explanation of drawings]

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, FIG. 2 is a radial cross-sectional view of the release film obtained by the apparatus shown in FIG. 1, and FIG.
The figure is a schematic sectional view showing an example of an apparatus for manufacturing a release film having a release layer only on the inner surface, and FIG. 4 is a radial sectional view of the release film obtained by the apparatus of FIG. 3. A... Release 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 is cured by radiation is extruded into a cylindrical shape to form a cylindrical extruded film. After forming a release agent layer of the silicone release agent on both the inner and outer surfaces of the extruded film, the extrusion 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, characterized by: 2. Heat-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, so that the thermoplastic synthetic resin for the base material is on the outside. 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, and the extruded film is extruded by blooming. After forming a release agent layer of the silicone release agent on the inner surface of the composite film, irradiating the composite film with radiation,
A method for producing a tubular release film having a release layer on the inner surface, comprising curing the release agent layer to form a release layer made of a thin film of silicone resin.