JPS63254140A - Method for modifying plastic film - Google Patents

Abstract

PURPOSE:To enable modification of different nature on the surface and in the interior with durability, by successively graft polymerizing the surface and interior of a film respectively with a monomer for modifying and surface and monomer for modifying the interior. CONSTITUTION:(A) Liquid layers of the same or different monomer (solution) for modifying the surface are formed on both surfaces of a plastic film by a spray, curtain flow method, etc., and a sheetlike material is then laminated on the respective layers to provide a thin and uniform state of the above- mentioned liquid layers. The sheetlike material side is irradiated with electron rays thereon to graft polymerize the monomer in the liquid layers and the sheetlike material is then peeled from both surfaces of the film. The unreacted monomer (solution) remaining in both film surfaces is removed and the film is then dipped and permeated with (B) a monomer liquid (solution) for modifying the interior. The permeated monomer is subsequently graft polymerized with radicals remaining in the interior of the film by irradiation with electron rays to carry out modification of the surface and interior of the film.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention involves graft polymerizing a modifying monomer onto the surface and inside of a plastic film to modify the surface and inside of the plastic film differently. about how it can be done.

(Prior technology) Plastic films are generally manufactured with quality designs for each use in which they are used in large quantities, so if the intended use is different from the intended use, they cannot be used as is, and the surface and interior must be modified differently before use. There are times when you have to.

Conventional methods for modifying plastic films to give them new functions include (1) adhering different types of polymers to the surface;
Or, a method is known in which a solution thereof is applied and dried to modify the film surface, and (2) a method in which 777- is polymerized on a plastic film through a catalytic reaction to modify the surface and interior. .

(Problems to be Solved by the Invention) However, even if these methods are used to impart different functions to the surface and interior of the film, it is not possible to do so by a single method. Therefore, it is conceivable to modify the entire plastic using method (2) and modify the surface using method (1), but method (1) requires the use of a film and a polymer for surface modification. Durability is a problem due to poor adhesion between layers.

Therefore, when modifying the interior or surface, a durable surface modification method was required.

(Measures to Solve the Problem) Therefore, the present inventors conducted intensive studies to solve the above problem, and as a result, they applied an electron beam to a plastic film once using a simultaneous irradiation method and a pre-irradiation method. By irradiating the film, a surface-modifying monomer and an internal-modifying monomer are sequentially graft-polymerized on the surface and inside of the film, respectively, and both can be modified in a different manner, and the adhesion between the film surface and the modified polymer is excellent. We developed a new method. That is, the present invention provides a liquid layer of the same or different surface-modifying monomers or a liquid layer of these monomer solutions on both sides of a plastic film, and after laminating a sheet-like material on each liquid layer, The laminated sheet material is irradiated with an electron beam from the side of the plastic film to graft-polymerize the monomer in the liquid layer on both sides of the plastic film, and then the laminated sheet material is peeled off from both sides of the plastic film to remove unreacted monomers or unreacted monomers remaining on both sides of the plastic film. The monomer solution is removed, and then the monomer solution for internal modification or this monomer solution is immersed in the monomer solution, and the infiltrated mower 7- is irradiated with the electron beam to remove the radicals remaining inside the plastic film. The surface and interior of the plastic film were modified by graft polymerization.

The modification method according to the present invention will be explained in detail below. First,
In the present invention, liquid layers of the same or different types of surface-modifying monomers or liquid layers of these monomer solutions are provided on both sides of a plastic film, and sheet-like materials are laminated on each liquid layer. By irradiating the electron beam from the side,
The surface of the plastic film is modified by graft polymerizing monomers in the liquid layer on both sides of the plastic film.

By laminating sheet materials like this on the surface of the film,
When an electron beam is irradiated from the sheet-like material side with the liquid layer thin and uniform, the electron beam easily passes through the sheet-like material and the surface-modifying monomer liquid layer, generating radicals throughout the film. . Among these radicals, those generated on the surface react with surface-modifying monomers adjacent to the film, and the monomers undergo graft polymerization. Therefore, if the sheet material is peeled off from both sides of the film after electron beam irradiation and the unreacted monomer or monomer solution on the organic resin surface is removed, only the graft-polymerized polymer remains on the film surface, making it possible to modify the surface. can.

During electron beam irradiation for surface modification, a liquid layer of monomer or monomer solution is provided on both sides of the film, and a sheet material is laminated thereon in order to make the liquid layer thin and uniform. If the liquid layer is left on the film surface, the liquid layer of the monomer or monomer solution will become discontinuous and a uniform film will not be formed because the plastic film surface is a low energy surface.

However, when a sheet material is laminated on top of the liquid layer, the monomer or monomer solution can be held thinly and uniformly between the plastic film and the sheet material due to capillary action. Therefore, the sheet materials are laminated so that they are in close contact with the film via the liquid layer.

The liquid layer may be formed on the film by any known method such as spraying, curtain coating, roll coating, etc. The sheet material may be a plastic film, a metal vapor-deposited film, or a metal film. Foil, paper, resin coated paper, metallized paper, etc. may be used.

Next, in the present invention, after modifying the surface as described above,
It is immersed in a monomer solution for internal modification that is different from the surface modification 7mer, or is immersed in this monomer solution, and the infiltrated monomer remains inside the film due to the electron beam irradiated during surface modification. The interior is modified by graft polymerizing the film with radicals.

During surface modification, radicals generated on the film by electron beam irradiation still remain inside even if those generated on the surface react with the surface-modifying monomer as described above. Therefore, when the film is immersed in the internal modification material 7~ and allowed to penetrate into the interior, the moa 7~ reacts with the radicals remaining inside and undergoes graph 1 polymerization. Therefore, the inside of the film can also be modified.

The mower used for surface modification and internal modification of the film in the present invention may be one having an electron beam-reactive functional group (ethylenic unsaturated double bond), and it may be a monomer claw, a solvent Containing moa 7- or a polymerization inhibitor such as Mohr's salt or hydroquinone may be added thereto.

According to the method of the present invention, the surface and interior of most plastic films can be modified, for example, even if the film is made of polyolefin, polyvinyl chloride, polyester, or polyvinyl alcohol.

(Example) In the example, Mffi stretched polyethylene terephthalate film (
Apply methacrylic acid to a thickness of 50μ (I+) using bar coater #3.
0, laminated a high-density polyethylene film (thickness: 50μI) from above, first provided a liquid layer of methacrylic acid on the lower surface of the high-density polyethylene film, and then applied trifluoroethyl methacrylate on the upper surface of this film. While coating in the same manner as above, a biaxial K-stretched polyethylene Tele7 crate film (thickness: 50 μm) was laminated, and a liquid layer of trifluoroethyl methacrylate was provided on the upper surface.

After that, from the top side, acceleration voltage 200 KeV, electron current 10
VIA, irradiated with electron beam at a dose of 1ONrad,
Methacrylic acid and trifluoroethyl methacrylate were graft-polymerized on the lower and upper surfaces of a high-density polyethylene film, respectively. After polymerization, the biaxially stretched polyethylene terephthalate films on both sides were removed, and the surface was ultrasonically cleaned in ethanol for 10 seconds and dried.

Next, the high-density polyethylene film whose surface was modified as described above was immersed in acrylonitrile at 70° C. for 10 minutes to modify the inside thereof, and then ultrasonically cleaned in acetone for 10 minutes and dried.

After drying, the contact angle of the film with water was measured.
The contact angle of the lower surface graft-polymerized with methacrylic acid is 54°, and the upper surface graft-polymerized with trifluoroethyl methacrylate is 115°. The top surface is
It was given water repellency.

In addition, when this film was heated under air with a load of 4097 mm2 at a temperature increase rate of 5/+n+n, 2
The film broke at 69°C. On the other hand, when a heat resistance test similar to the above was carried out on a film that was simply graft-polymerized with methacrylic acid on the bottom surface and trifluoroethyl methacrylate on the top surface without any internal modification, the film broke at 149°C, indicating that the heat resistance was improved in the internally modified film.

Example 2 A low density polyethylene film was used instead of the high density polyethylene to be modified = 8- film in Example 1, and 2-hydroxy methacrylate was used instead of trifluoroethyl methacrylate as the liquid layer provided on the upper surface. Using ethyl, the surface and internal modification of a low density polyethylene film was carried out in the same manner as in Example 1.

As a result, the contact angle with water was 95° for the lower surface modified with methacrylic acid, 80' for the upper surface modified with 2-hydroxyethyl methacrylate, and 104° for the untreated low-density polyethylene film. Hydrophilicity was imparted to both sides.

Further, when this film was subjected to a tensile test at a speed of 50 + nm/+ nin, the tensile strength was 3.8 x 1
02K 13/+n m2. On the other hand, acrylonitrile is applied to the bottom surface and methacrylic acid is applied to the top surface.
When a tensile test similar to the above was carried out on a film obtained only by graft polymerization of 2-hydroxyethyl, the tensile strength was 2.1×10 2 K g/mm 2 , which was weaker than that of the internally modified film.

(Effects of the Invention) As described above, according to the present invention, it is possible to graft-polymerize the surface and interior of a plastic film with a monomer of a different kind to the film, thereby making it possible to modify the surface and interior differently. and the surface-modified polymer are strongly bonded to each other. Furthermore, since electron beam irradiation is carried out by making the monomer layer uniformly thin, it is possible to generate radicals in the film with one irradiation, and even with a low voltage electron accelerator (acceleration voltage 35'0 KeV or less). This can be done by generating radicals.

Claims (1)

[Claims] After providing liquid layers of the same or different types of surface-modifying monomers or liquid layers of these monomer solutions on both sides of a plastic film, and laminating sheet materials on top of each liquid layer, electron beams are applied from the sheet material side. irradiation to graft-polymerize the monomer in the liquid layer on both sides of the plastic film, and then peel the laminated sheet material from both sides of the plastic film to remove unreacted monomer or monomer solution remaining on both sides of the plastic film, Thereafter, it is immersed in an internal modification monomer solution or this monomer solution to be infiltrated, and the infiltrated monomer is graft-polymerized inside the plastic film using the radicals remaining inside the plastic film by the electron beam irradiation. A method for modifying plastic film.