JPH10156918A - Production of composite film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a composite film not requiring troublesome work such as corona discharge treatment by melt-extruding polychlorotrifluoroethylene(PCTFE) in a film form and contact-bonding an ethylene/glycidyl methacrylate copolymer film with this extruded film held in a molten state. SOLUTION: After polychlorotrifluoroethylene(PCTFE) is melt-extruded in a film form, an ethylene/glycidyl methacrylate copolymer (EG) film or an ethylene/glycidyl methacrylate/vinyl acetate terpolymer (EGV) film is brought into contact with the formed PCTFE film held to a molten state to be integrally bonded to the PCTFE film by the heat possessed by PCTFE. The EG film 4 (or EGV film) wound around a delivery roll 3 is delivered from the roll 3 and guided to the PCTFE film 2 to be bonded thereto. After the PCTFE film and the EG or EGV film are integrally bonded, the bonded film is cooled by a cooling roll 5 to obtain a composite film 6 wherein the EG or EGV layer is formed on the surface of the PCTFE layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a composite film having polychlorotrifluoroethylene (hereinafter referred to as "PCTFE") as a base material and a hot melt adhesive layer formed on the surface thereof.

[0002]

2. Description of the Related Art PCTFE films have excellent moisture resistance and are useful as coating materials for electroluminescent elements, as described in, for example, Japanese Utility Model Application Laid-Open No. 57-127898. It is also used as a coating material for medical materials, medicines and the like.

[0003] When a PCTFE film is used for the above purpose, a hot melt adhesive layer is usually provided on the surface thereof in order to improve the covering effect.

[0004] Then, the P with a hot melt adhesive layer
A method for producing a CTFE film is disclosed in JP-A-63-21.
No. 8351, (a) PCT
FE, ethylene-glycidyl methacrylate-vinyl acetate terpolymer (hereinafter referred to as “EGV”) and ethylene-ethyl acrylate-maleic anhydride terpolymer (hereinafter referred to as “EEM”) are coextruded to form an EGV layer. To obtain a composite film having as an intermediate layer, and (b) P
One surface of the CTFE film is subjected to corona discharge treatment, and EGV and EEM are co-extruded on the treated surface so that the EGV is in contact with the treated surface, and then cooled while being pressed by a pressure roll to form a composite having the EGV layer as an intermediate layer. Methods for obtaining films are known.

[0005] The composite film obtained by these methods has a large adhesive force between the PCTFE layer as the base material and the EEM layer as the hot melt adhesive layer. There is an advantage that delamination hardly occurs with the adhesive layer, which is preferable in this respect.

[0006]

However, (a)
The method of (1) requires special equipment to simultaneously extrude three materials having different melting points, namely, PCTFE, EGV and EEM, while the method (b) requires EGV and EEM.
Prior to extrusion, the PCTFE film had to be subjected to corona discharge treatment.

Accordingly, an object of the present invention is to provide a novel method for producing a composite film which does not require a special device and does not require a troublesome operation such as corona discharge treatment.

[0008]

That is, in the method for producing a composite film according to the present invention, PCTFE is melt-extruded into a film, and while the PCTFE is in a molten state, an ethylene-glycidyl methacrylate copolymer (hereinafter referred to as "EGTF") is prepared. ) Or a EGV film in contact and bonding, and then cooling.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS PCTFE used in the present invention
May be a homopolymer of chlorotrifluoroethylene or a copolymer with an ethylenically unsaturated monomer copolymerizable with chlorotrifluoroethylene (for example, vinylidene fluoride). However, in the case of a copolymer, it is preferable to use one having an ethylenically unsaturated monomer content of 10% by weight or less from the viewpoint of moisture resistance.

Hereinafter, a method according to the present invention will be described with reference to the drawings. In the present invention, first, PCTFE
Is melt extruded into a film. The melt extrusion of PCTFE does not need to be exceptional and can be performed using an apparatus used for melt extrusion molding of a general thermoplastic resin. For example, as shown in FIG.
CTFE2 is melt extruded into a film. The extrusion temperature is set appropriately, but to obtain a film with a smooth surface, PC
It is preferable to set the melting point of TFE to be about 100 ° C. higher than the melting point (about 210 to 220 ° C.). The thickness of the film is not particularly limited, but is usually about 25 to 350 μm.

After the PCTFE is melt-extruded into a film, the EG film or the EGV film is brought into contact with the PCTFE while the PCTFE is in a molten state.
The PCTFE film and the EG film or EGV film are joined and integrated by the heat of E. Of course, the EG film or the EGV film may contain an appropriate amount of an additive such as an antioxidant and a filler.

As shown in FIG. 1, the contact between the molten PCTFE and the EG film or the EGV film is performed by unwinding the EG film 4 (or the EGV film) wound around the unwinding roll 3 from the roll 3 and guiding the EG film 4 to the PCTFE film. Can be done. EG is, for example,
Since EGV is commercially available from Sumitomo Chemical Co., Ltd. under the trade name of Bond First E, for example, from Sumitomo Chemical Co., Ltd. under the trade name of Bond First 2B and Bond First 7B, these are purchased. It can be used after being formed into a film.

After the PCTFE and the EG film or the EGV film are joined and integrated as described above, the resultant is cooled by the cooling roll 5 so that the surface of the PCTFE layer has
A composite film 6 having a layer or an EGV layer formed thereon can be obtained.

In the present invention, PCTFE and EG
In order to improve the bonding strength with the film or the EGV film, the pressing roll 7 is arranged, and PCTFE and E
It is preferable that the G film or the EGV film be contacted and pressed (in the example shown in the figure, the pressing roll 7 is pressed against the cooling roll 5 to be in a pressed state) and cooled.

[0015]

The present invention will be described below in detail with reference to examples.

EXAMPLE A PCTFE pellet is extruded into a film so as to have a thickness of 100 μm using a melt extruder in which the temperature of an extrusion die 1 is set at 310 ° C. in the same manner as shown in FIG.

Then, the molten PCTFE2 is
The EGV film (Bond Fast 7B, thickness 70 μm) fed from the feeding roll 3 is brought into contact with the PCTFE.
The PCTFE and the EGV film were joined and integrated by the heat of the above and cooled along the surface of the cooling roll 5 to obtain a composite film having an EGV layer formed on one surface of the PCTFE. In addition, the pressing roll 7 is arranged so as to face the cooling roll, and the PCTFE and the EGV which are brought into contact with each other.
The film was pressed.

The EGV layers of the two composite films are faced to each other, a hot roll (140 ° C.) is run thereon, and they are bonded to each other, and then cut to a width of 1 cm. And EG
When the adhesive strength between the V layers was measured, it was 1.9 kg. This value is almost the same as that of the conventional product. From this, the PCT in the composite film obtained by the method of the present invention is obtained.
It was found that the adhesive force between the FE layer and the EGV layer was practical. The measurement was performed using an Instron type tensile tester (Tensilon, manufactured by Toyo Baldwin Co., Ltd.) at a temperature of 25.
It carried out by 90 degree peeling method on conditions of 200 degreeC and the tensile speed of 200 mm / min.

[0019]

According to the method of the present invention, no special equipment is required, and the surface of the PCTFE layer as a base material is made of EG or EGV without performing an adhesive treatment such as a corona treatment. A composite film in which the hot melt adhesive layer is firmly joined can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a method for producing a composite film according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Extrusion die 2 PCTFE 4 EG film 5 Cooling roll 6 Composite film 7 Press roll

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Claims (1)

[Claims] 1. A polychlorotrifluoroethylene is melt-extruded into a film, and while the polychlorotrifluoroethylene is in a molten state, an ethylene-glycidyl methacrylate copolymer film or an ethylene-glycidyl methacrylate-vinyl acetate terpolymer is prepared. A method for producing a composite film, comprising: bringing a film into contact with each other, bonding the film, and then cooling the film.