JPS6056310A - Heat-bondable transparent conductive film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transparent conductive film that can be thermally bonded in a conductive layer.

Plastics such as polyolefin resins and polyvinyl chloride resins are widely used in molded products, films, etc. due to their excellent physical and chemical properties.
Like many other plastics, they have a high electrical resistance, so they tend to be sensitive to static electricity due to friction, which can cause two types of problems.

In particular, ICs, which have become rapidly popular in recent years, have problems such as the internal circuits being destroyed by static electricity of a few gobolds, resulting in defective products. It is necessary to impart excellent conductivity and properties to the materials used.

Conventionally, methods for imparting electrical conductivity to plastic films include (1) applying various surfactants to the surface or adding them internally;

(2) Internally adding conductive filler materials such as carbon black and metal fibers (8) Forming a metal thin film on the surface.

(4) Apply conductive paint to the surface.

There are etc.

Films produced by the method of surface coating or internal addition of a surfactant as described in (1) above have a surface resistivity of approximately 10,100 or more and cannot be used in applications that require a high degree of conductivity. There is.

In addition, the film produced by the method of internally adding a conductive filler material in (2) above provides instant conductivity, but because it is opaque, there are problems such as the inability to confirm the contents inside one bag. It's inconvenient.

In addition, the film produced by the method of forming a metal thin film on the surface of (8) above has excellent transparency and conductivity, such as a film with gold vapor-deposited, but is extremely expensive. Used for special purposes rather than general purpose.

In addition, the film produced by the conventional method of applying conductive paint to the surface (4) above has the same properties as the method (2) of internally adding a conductive filler material. However, it has drawbacks such as being opaque and making it impossible to confirm the contents when processed into a single bag.

Furthermore, the thermal adhesion of the conductive layer is insufficient.

In some cases, it may be necessary to interpose a heat-adhesive coating layer on the bonded area.

That is, there is a need for a conductive film that is transparent, has thermal adhesive properties, and is inexpensive. As a result of extensive research with the aim of providing
Thermoadhesive film surface pores 4 conductive @ powder and thermoplastic 404
The present invention was achieved by laminating a thin film layer mainly composed of fat and a thin film layer mainly composed of fat.

In other words, the present invention consists of a thin IfIA layer with a thickness of 8 μm or less, which is composed of 50 vol. layer and 'f! : Consisting of lamination, it provides an inexpensive film with excellent surface conductivity, transparency, and thermal adhesion on the conductive surface.

In terms of history, when the particle size of the conductive fine powder is 0.4 cm or less, and is smaller than the wavelength of visible light, there is little scattering of light, and the decrease in transparency due to the thin film layer containing the conductive fine powder is small.
When the thickness of the thin film layer is small.

This effectively eliminates transparency. In addition, the thermal adhesion between a conductive surface and another conductive surface of a thermal adhesive transparent plastic film coated with a thin film layer consisting of conductive fine powder and thermoplastic resin is determined by the thermal adhesion between the conductive surface and another conductive surface. The intervening conductive thin film layer preferably has a volume ratio of 50 cm or less, preferably 40% or less of conductive fine powder, and the remainder of thermoplastic resin, and has a thickness of 8 μm.
If the thickness is less than m, preferably less than 1 μm, it can be maintained at a level that does not cause any practical problems. In other words, it is transparent;
Provides an inexpensive conductive film with thermal adhesive properties on conductive surfaces.

Examples of specific metals and metal compounds as the conductive fine powder applied in the present invention include metal oxide imitation powders such as tin oxide containing antimony and zinc oxide containing aluminum, and N+I Chi, Co+Ag, etc. Examples include fine metal powder.

In addition, thermoplastic resins to be blended with the $2 lightning fine powder include polyester-based, urethane-based, acrylic-based, and vinyl-based resins, and examples of the thermolinkable transparent plastic film include polyethylene, Polyolefins such as polypropylene and ionomers, vinyl-based resin films such as vinyl acetate, and laminated films of these and other transparent resin films are applicable.

In addition, methods for laminating a conductive thin film layer on a heat-adhesive coated plastic film include a spray method using an aqueous medium or a solvent solution, and a gravure roll coating method.

Coating method such as barcode method.

Any suitable method such as hot-melt coating, co-extrusion with a heat-adhesive resin film, etc. can be used.

Next, the present invention will be explained by way of examples.

These are illustrative and are two inventions! 1 This is not intended to be limiting.

The conductivity (@pressability resistance), transparency, and thermal adhesion shown in the examples were measured using the laminated films as samples in the following manner.

(1) Tetraelectricity (surface specific resistance) The size of the surface in contact with the sample film is 10
++mX 50wn5. A long sword shape with a weight of 250 mm, placed with a lux distance from the shade, connected to the tester (day shift 1) IGITAL HiTJ (STE 8205 type) with a lead wire, read the resistance, and set a value 5 times that value. Surface specific resistance (2) O (2) Transparency: Total f by the parallel light transmittance measurement method specified in JIS K-67, 14;
T)-Measured using H67 model (8) Thermal adhesion tester industry ■ A heat seal bar with a width of 21 was attached to a sea bream bar sealer, and thermal adhesion was performed at 170°C x z seconds. After cooling,
Evaluate the adsorption properties by pulling in the direction of peeling with your fingertips (7).

O...The film stretches in the area below the heat bonding part Δ・
... Easily peels off at the heat-bonded part ×... Examples 1 to 4 that are not heat-bonded Particles made of tin oxide containing antimony and have a diameter of approximately 0°04.
Using the commercially available Shintron C-4401 manufactured by Ikito Paint Co., Ltd. as a conductive fine powder paint consisting of conductive fine powder of μ, soluble polyester, and solvent, the specified transparent thermal bridge new Apply it to the surface of the plastic film, and
It was dried in a 5-piece dryer.

Conductivity? The thickness of the +J film layer was determined from the difference in weight of the film before and after coating. The conductivity and transparency of the resulting film! 4 Adhesion results are shown in Appendix NS1.

4. As is clear from the results above, r % 1) j nature (Table.

1YIJ specific abrasiveness) 1 was 60 or less, transparency (light transmittance) 80% or more, and a transparent conductive film capable of forming a thermal layer was obtained.

Examples 5 to 8 The same kind of f+ was added to the conductive fine powder paint used in Example 1.
Conductive fine powder Mitsubishi Metals (Yamanashi, product name 7S conductive fine powder:
'1-1) and dispersed using a ball mill to prepare a paint containing a high volume of fine powder of isomorphic condensation.
A coated film was prepared in the same manner as 4I, and the performance measured for the rolled film 1C is shown in Attached Table 1.

As you can see from the results, 1! Even when the conductive fine powder in the J type component was about 4.0 to 5 Q vo 1%, the thermal adhesion was almost maintained. Attached Table 1 shows the results of the conductivity, transparency, and thermal adhesion of the film obtained by coating it on a biaxially oriented polyester film that is non-thermally bondable as a material film.

As can be seen from the results, the conductivity and transparency were almost the same as in the example, but the thermal adhesion was surprisingly poor.

Comparative Examples 2 to 3 A conductive thin film layer was prepared in the same manner as in the example, and conductive fine powder was further added to the conductive fine powder paint obtained in the example, and 1% of the fine powder was dispersed in a ball mill. The conductivity of the film obtained by coating with a high composition,
The results of transparency and thermal adhesion are shown in Attached Table 1.

As can be seen from these results, although the conductivity is improved, the transparency is decreased and the thermal adhesion is poor.

Comparative Example 4 Zinc white with a particle size of about 3.5μ was added to Byron S (product name: Toyobo Co., Ltd., liJ soluble polyester system) dissolved in ethyl acetate, and dispersed using a ball mill. A paint-like dispersion was obtained.This liquid was applied in the same manner as in the examples. As can be seen from the results, it is clear that when the particle size of micro-seven powder is 0.4μ or more, there is almost no transparency.

[Margin below]

Claims (1)

[Claims] A thin film layer with a thickness of 8 or less consisting of 50 vol or less of conductive fine powder with a particle size of 04 or less, the remainder being a thermoplastic resin, and a transparent plastic film layer that can be thermally bonded are laminated. A transparent 4-frost 1-character film that can be thermally bonded with a conductive layer.