JPH02219640A - Polymer film for easy adhesion working - Google Patents

Abstract

PURPOSE:To improve remarkably the adhesion strength of a surface without reducing light-permeability by providing a specified very thin metallic film on a polymer film, after at least one surface of the polymer film has been blast-worked. CONSTITUTION:The metallic film provided at least on the roughened surface of the polymer film with roughened surface, is composed of a metal containing the atom having the effect for activating the low energy surface of the polymer film such as a fluorine plastic film or a polyester film. As the metal containing such atom, Ti, Al and other transition metals having similar effect are used, and definitely each metallic element such as Zr, Cr, Mo, W, Fe, Co, Ni are used. The thickness of the metallic film covering the surface of the polymer film is 5-100Angstrom . The thickness of the metallic film composed of the metallic atom of Ti is 10-90Angstrom . The metallic film is preferably formed continuously on the whole surface of the polymer film from the point of view of the durability of a sealed object, and especially 20Angstrom or more of the thickness is preferably from such point of view.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to the sealing of electronic devices such as solar cells and electroluminescent lamps, medical products, and foods whose performance is significantly degraded by the permeation of water vapor and various gases. .

The present invention relates to an easily adhesive processed polymer film which is applied to packaging materials and whose purpose is to significantly improve the durability of such members.

[Conventional technology and its problems] Polymer films such as fluororesin films and polyester films, which have a high ability to prevent the permeation of water vapor and various gases, are difficult to heat-fuse, so such polymer films cannot be sealed as they are. , it is inconvenient to apply to packaging materials. Therefore, a heat-sealable thermoplastic adhesive layer is laminated and applied on the surface of such a polymer film.

However, since polymer films such as fluororesin films and polyester films have low surface energy and are inert, a method of combining sandblasting and glow discharge treatment of the surface to be adhered disclosed in JP-A No. 53-69593 has been proposed. , a method of forming a film of metal, metal oxide, inorganic oxide, or silane coupling agent as disclosed in JP-A No. 63-99581, and then laminating a thermoplastic adhesive layer. It is being

However, in such pretreatment methods, the adhesive strength between the polymer film and the thermoplastic resin is not necessarily sufficient, and interfacial peeling may occur from the adhesive surface.

In particular, when flexible electroluminescent lamps, solar cells, etc. are sealed with the laminated film and subjected to repeated bending deformation, interfacial delamination occurs, resulting in a lack of reliability, and the adhesion between the polymer film and thermoplastic resin. There is a long-awaited desire to improve sex.

[Object of the Invention] The present invention was made in view of the current situation, and an object of the present invention is to provide a polymer film having an adhesive surface with excellent peel strength as an easily adhesive processed polymer film.

[Structure and function of the invention] For the above purpose, the present inventor developed a fluororesin film.

To improve the adhesion of polymer films that are difficult to heat-seal, such as polyester films, when laminating thermoplastic adhesive layers that can be heat-sealed in order to apply them to sealing and packaging materials. As a result of extensive research, we discovered that by blasting at least one side of a polymer film and then applying a very thin, specific metal thin film, it is possible to significantly improve surface adhesion without impairing optical transparency. , arrived at the present invention.

That is, the present invention provides an easily adhesive processed polymer film characterized in that at least one surface of the polymer film is blast-processed, and a metal thin film made of a metal having the effect of activating the surface is laminated on at least one surface. be.

In addition, as in the present invention, adhesion can be greatly improved by coating the blasted surface with a very thin metal film, specifically less than 10 Å, and in extreme cases only several layers, which cannot be called a continuous film. Although the reason for this is not clear, it is thought to be due to activation of the film surface by the laminated metal.

The present invention will be explained in detail below.

The polymer film of the present invention is preferably a polymer film that is difficult to heat-seal, such as the aforementioned fluororesin film or polyester film, although it is not particularly limited. Fluorine-based resin films and polyester resin films, which are suitable for use as sealing films for electronic components having light-emitting parts and have poor adhesive properties, are suitable. A thickness of about 25 to 300 μm is usually used due to its flexibility.

Further, in the present invention, at least one side of the polymer film is subjected to blast processing. Blasting is performed by spraying fine powder of corundum, silica, silicon carbide, etc. with a mesh size of about 80 to 200 onto the surface to be treated along with a jet stream, or by dropping the fine powder onto a disk rotating at high speed. The surface of the polymer film is processed by colliding with the surface to be processed using the centrifugal force of the plate.

In this case, by controlling the type of powder, the size of the fine powder, and the collision speed, irregularities of unspecified shape and different sizes can be formed.

The degree of roughening of the surface of a polymer film having such a surface is expressed by gloss as defined in JIS 5400, but the gloss of a polymer film having a rough surface suitable for the present invention is 50% or less. It is.

Next, in the present invention, the metal thin film provided on at least the roughened surface of the roughened polymer film is a fluororesin film as described above.

It consists of metal atoms that have the effect of activating the low energy surface of polymer films such as polyester films. Examples of such metal atoms include Ti and /J shown in Examples below, as well as transition metals that can obtain similar effects, specifically Zr, Cr, NO, W, and Fe.

Examples include Co and each old metal element. Among them, Ti is particularly preferable because it has a large effect of increasing adhesive strength as shown in the examples. Note that, since the metal thin film of the present invention is oxidized in the atmosphere depending on the metal used in its surface layer, it goes without saying that it includes those having such an oxide layer on the surface layer. In the present invention, it is important that the bottom layer portion on the side of the activated surface in contact with the roughened polymer film is made of metal atoms.

The metal thin film is formed by a known physical vapor deposition method that has the effect of activating the surface of a polymer film, such as a vacuum evaporation method, a sputtering method, or an inblating method. For example, in the sputtering method, the above-mentioned roughened polymer film is used as a substrate, a target made of, for example, Ti metal is arranged as a counter electrode, and a DC voltage is applied between both electrodes in an Ar inert atmosphere of 10-3 rorr. A glow discharge is generated to sputter Ti metal to form a thin film of Ti metal atoms on the roughened polymer film.

In this way, a metal thin film made of a metal such as a transition element such as Ti is coated on at least one surface of the roughened polymer film, but considering the use of the present invention, the original light transmittance of the polymer film is In order to maintain the adhesive strength, and as is clear from the examples described below, from the viewpoint that a large adhesive force can be obtained,
The thickness of the metal thin film coated on the surface is 5 to 100. The original light transmittance of a roughened polymer film varies depending on the film thickness, the type of roughened polymer, etc.87
~95%. When the surface of such a polymer film is roughened, the gloss level decreases as described above, but as is clear from the examples described later, substantial transparency is restored by adhering with a thermoplastic resin. By the way, in application fields such as solar cells and electroluminescent lamps, glass plates are used as moisture-proof transparent members, but in the wavelength range of 400 to 1100 nm, the light transmittance of soda lime glass is around 84%, while the light transmittance of white plate glass is about 84%. It is said to be around 91.6%. Therefore, considering the optical properties of the glass plate, it can be seen that the above film thickness is sufficient for the transparency required in various application fields including high performance fields such as solar cells. At the same time, as is clear from the examples described later, surprisingly, adhesive strength close to the peak can be obtained in this film thickness range. The film thickness of the metal atoms that provides such light transmittance varies depending on the type of metal atoms to be applied, and is difficult to determine unambiguously. For example, in the metal thin film made of Ti metal atoms shown in the example, 90
Å or less, and in a metal thin film made of metal atoms, it is 30 Å or less. - On the other hand, the lower limit of the thickness of the metal thin film is determined from the limit that can bring out the effect of improving the adhesion of the roughened polymer film. Unlike on a smooth surface, a film thickness of a certain level or more is required on a roughened polymer film, and in particular, in order to achieve this effect without substantially impairing the transparency of the roughened polymer film. In the case of Ti, the thickness of the metal thin film is preferably 90 Å or less and 10 Å or more, and more preferably 10 to 70 in consideration of adhesiveness. Further, from the viewpoint of durability of the object to be sealed, it is preferable that the metal thin film is formed as a continuous film over the entire surface of the film, and in consideration of this, a thickness of 20 Å or more is particularly preferable.

In the present invention, a very thin metal thin film is provided on at least one side of the roughened polymer film, and for example, the negative side can be used to improve adhesion, and the other side can be used to improve printability.

That is, the surface of the roughened polymer film coated with such a metal thin film is such that the coated surface is composed of a metal thin film that is a representative of high-energy substances, and the roughening exerts an anchoring effect.
The surface properties are significantly improved. The metal thin film coated surface of the film is opposed to, for example, the photoelectric conversion surface of a flexible amorphous silicon solar cell on a polymer substrate, an ethylene-vinyl acetate copolymer resin film is inserted between them, and both are heated with a roll. As a result of heat-pressure bonding using the above-mentioned method, the two were firmly stuck together and could not be easily peeled off. On the other hand, surfaces that are not coated with conventional metal thin films, surfaces that are only roughened,
Alternatively, when a surface on which only a metal film is formed without roughening is similarly bonded to the solar cell described above, the peel strength of the bonded surface is insufficient as shown in the comparative example below.

In this way, the easily adhesive processed film of the present invention, which is made of a roughened polymer film whose surface has been roughened by blasting and is coated with a metal thin film, has significantly improved surface properties.
It also improves the effect of preventing water vapor and various gas transparency, has excellent adhesion properties, gas barrier properties, and light transmittance at the same time, and can also provide flexibility as required.

In addition, when the above-mentioned easily adhesive processed polymer film of the present invention is used as a sealing film for an electronic component having the above-mentioned receiving/emitting part, a heat-sealable thermoplastic resin layer is provided on the easily adhesive processed surface. A laminated form is preferable from the viewpoints of sealing effect, productivity of the sealing process, sealing durability, and the like.

Note that the thermoplastic resin layer that can be heat-sealed here is
This refers to a plastic layer that can be bonded by heat and pressure, and representative examples thereof include the following.

Polyolefins such as polyethylene, polypropylene, ethylene propylene copolymers, polyesters, polyamides, ionomers, ethylene vinyl acetate copolymers, acrylic resins such as acrylic esters and methacrylic esters, polyvinyl acetals, phenols, modified epoxy resins, etc. , copolymers and mixtures thereof, but are not necessarily limited thereto.

Among these, polyester, polyamide, ionomer,
Acrylic resin, ethylene/ethyl acrylic acid copolymer,
Ethylene vinyl acetate copolymer is preferred.

The thickness of the thermoplastic resin is determined by its adhesive strength and gas barrier properties.
The range is preferably 5 to 50 μm, more preferably 10 to 50 μm.
30 μm is desirable.

The thermoplastic resin layer can be laminated by dissolving the components of the thermoplastic resin layer in an organic solvent and coating it, by melting the components of the thermoplastic adhesive layer and extrusion laminating, or by applying the thermoplastic resin layer in advance. A known method such as a method of preparing a layered sheet and adhesively laminating the sheets by dry laminating or the like can be adopted.

The heat-sealing temperature of the thermoplastic resin layer can be appropriately selected depending on the characteristics of the thermoplastic resin layer used, but it is desirable that the thermoplastic resin layer can be heat-sealed at a temperature of 80 to 180°C.

[Effects of the Invention] As described above, the easily adhesive processed polymer film of the present invention uses a polymer film with excellent transparency and gas permeation prevention properties, and is a thin film that substantially does not impair its transparency. Its surface is modified with a metal thin film to improve adhesion. Therefore, by laminating an adhesive layer or an adhesive layer on the surface-modified surface side of which at least a metal thin film is laminated on the blasted surface, it can be used as a moisture-proof protective material for solar cells, electroluminescent lamps, and the like. In particular, in the case of an amorphous silicon solar cell with a polymer substrate or a coated type electroluminescent lamp with a polymer film substrate, the easily adhesive processed polymer film of the present invention or a laminated adhesive layer or adhesive layer thereof is laminated and coated. This makes it possible to seal these elements without impairing their flexibility, making them suitable for application.

As described above, the present invention is very useful and can be applied to a wide variety of moisture-proofing applications.

Examples of the present invention are shown below.

[Example] Two types of films with a thickness of 100 μm made of a chlorotrifluoroethylene (CTFE) polymer and a polyethylene terephthalate film were taken up as polymer films with excellent transparency.

These films are placed in a sandblasting machine and 8
The surface was scanned with 0 mesh corundum fine powder together with a jet stream to obtain a blasted roughened film with a gloss level of 9%.

Using both this blasted film and a non-blasted film for comparison, these films were mounted on a roll-to-roll type DC sputtering device,
Using Ti metal and M metal plates as metal targets, introduce argon gas, and under a pressure of 1.3
In the case of W, the film speed was varied in the range of 15 to 40 CIII/min, and in the case of M, the sputtering input power was varied in the range of 1 to 5 -, and the film speed was varied in the range of 6 to 30 cmZ. A thick metal thin film was deposited. Note that the film thickness was measured by fluorescent X-ray method.

The measured values of the integrated transmittance of each sample of the metal-coated film obtained are shown in Table 12 and Table 2.

Next, the metal-coated surfaces of the nylon film with a thermoplastic hot-melt adhesive layer made of ethylene-ethyl acrylate copolymer with a thickness of 50 μm and the metal-coated film samples of various thicknesses mentioned above were heated at 120°C. The material was passed between rolls heated to 100 mL and laminated together under a pressure of 4 kg/cm2.

After that, these pasted laminates were tested using a tensile testing machine (manufactured by Instron) at a tensile speed of 20 cm/min, which is highly sensitive for detecting T-shaped peeling (JIS 6854), which can approximate the peeling of stickers, etc. The adhesive strength between the nylon film and the fluororesin film was measured, and the results shown in Table 19 and Table 2 were obtained.

Front polyethylene terephthalate film Sample combining blasting and metal thin film, which is a feature of the present invention 4.5.6.8.9.13.14゜16
It can be seen that the adhesive strength is extremely high. In addition, the decrease in transmittance is small in the metal film thickness range as in the above sample.

As is clear from the above Examples and Comparative Examples, the metal-coated blast processed film of the present invention has a high energy coating on the metal-coated surface without impairing light transmittance, in other words, has improved adhesion. It can be used as a moisture-proof, light-transmitting film in solar cells, electroluminescent lamps, etc. without losing flexibility.

Claims (1)

[Claims] 1. An easily adhesive processed polymer characterized in that at least one side of a polymer film is blasted and a metal thin film made of a metal having the effect of activating the surface is laminated on at least one side. film. 2. The metal thin film is made of Ti, Zr, Cr, Ho, W, Fe.
2. The easily adhesive processed polymer film according to claim 1, which is one or more metal elements selected from the group consisting of , Co, Ni, and Al, and has a film thickness of 5 Å to 100 Å. 3. The metal thin film is made of Ti and has a thickness of 10 Å to 9
The easily adhesive processed polymer film according to claim 1, which has a thickness of 0 Å. 4. Claim 1, wherein the metal thin film has a thickness of 20 Å or more.
The easily adhesive processed polymer film according to any one of items 1 to 3. 5. The easily adhesive processed polymer film according to any one of claims 1 to 4, wherein the metal thin film is a vapor-deposited thin film laminated by a physical vapor deposition method.