JPH0139348B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to transparent conductive films. Specifically, the invention relates to a film that has excellent transparency and good conductivity and is used for packaging electronic devices such as IC elements and semiconductor printed circuit boards. BACKGROUND ART In recent years, electronic devices such as IC elements and semiconductor wafers have come into widespread use, and the packaging materials used to package them are also required to have various physical properties. In other words, electronic components such as those mentioned above are extremely sensitive to electricity, and when these electronic components are wrapped in synthetic resin film, for example, the function of the electronic components may be destroyed by the static electricity generated in the synthetic resin film. This improvement was desired. For this reason, in the past, carbon black or fine metal powder was kneaded into this synthetic resin film to make it conductive, and it was used as a packaging material, or metal was vapor-deposited onto the synthetic resin film to make it conductive. However, it cannot be said that they are fully satisfactory in terms of manufacturing cost, conductive performance, etc., and in particular, products in which carbon black or fine metal powder is kneaded into synthetic resin are inconvenient in terms of product management because the contents cannot be seen after packaging. There is a flaw in that. The inventors of the present invention have conducted various studies in order to provide a conductive film that is transparent, inexpensive to manufacture, and has excellent conductive performance, eliminating the defects of conventional conductive films as described above. By using a film with a special layer structure, the object was achieved and the present invention was completed. That is, the gist of the present invention is that an antistatic layer made of polyolefin containing an antistatic agent is provided on one side of a barrier layer made of polyolefin not containing an antistatic agent, and an adhesion promoter layer is provided on the other side of the barrier layer. A transparent conductive film is provided with a transparent conductive layer through the film, and the adhesion promoter is a urethane-based, organic titanate-based, or polyethyleneimine-based adhesion promoter, and the conductivity is made of tin oxide. The present invention relates to a transparent conductive film characterized by being formed by coating a coating material containing a conductive substance as a main component. An example of the film of the present invention will be explained in more detail below with reference to the drawings. 1 and 2 are longitudinal sectional views of the film of the present invention. In the figure, 1 is an antistatic layer, 2 is a Bayer layer, 3 is a conductive layer, and 4 is an adhesion promoter layer. The transparent conductive film of the present invention is generally composed of an antistatic layer 1, a barrier layer 2, and a conductive layer 3. The antistatic layer 1 is made of polyolefin containing an antistatic agent, and examples of the polyolefin include polyethylene, polypropylene, and ethylene.
Propylene copolymer, polybutene 1, ethylene-
Vinyl acetate copolymers are used, especially those with a melt index (MI) (based on JIS-K6760) of 0.4 to
10 g/10 minutes, polyethylene with a molecular weight distribution index (α) expressed by (melt index value) x (flow ratio value) x (melt tension value) of 30 to 400, preferably 40 to 300 is suitable. used for. Here, the flow ratio is the ratio of the melt index when the load is 2.16 kg as described above to the melt index when the load is 21.6 kg, and is a value determined by the following formula. Flow ratio = MI at 21.6Kg load/MI at 2.16Kg load
MI Also, melt tension refers to the resin JIS-K6760.
Tension (g) measured at a distance of 25 cm from the nozzle when extruded from the nozzle used in the melt index measurement method at a resin temperature of 160°C at an extrusion rate of 0.25 g/mm and taken off at a take-up speed of 1.52 m/mm. It is. As the antistatic agent contained in the antistatic layer 1, any of nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants can be used. Nonionic surfactants include, for example, aliphatic alcohols such as polyoxyethylene (8 to 18 carbon atoms).
) ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene/polyoxypropylene block polymer, polyoxyethylene sorbitan fatty acid (having 8 to 22 carbon atoms, the same applies hereinafter) ester, polyoxyethylene glycerin fatty acid ester, polyethylene glycol Fatty acid ester, polyoxyethylene fatty amine, sorbitan fatty acid ester, glycerin fatty acid ester, propylene glycol fatty acid ester, sucrose fatty acid ester, fatty acid alkanolamide, citric acid mono (di or tri) stearyl ester, pentaerythritol fatty acid ester, tri Examples include methylolpropane fatty acid ester, polyglycerin fatty acid ester, polyethylene glycol, polypropylene glycol, N,N-bis(2-hydroxyethyl) aliphatic amine, and condensation products of fatty acids and diethanolamine. Examples of anionic surfactants include alkyl sulfonates (the number of carbon atoms in the alkyl group is 4 to 4).
22, its salts are Na salt, K salt, _NH4 salt, etc. same as below. ) alkylbenzene sulfonate,
Alkylnaphthalene sulfonate, α-olefin sulfonate, polyoxyethylene alkyl ether sulfate, alkyl sulfate, sodium alkyl sulfosuccinate, higher alcohol ethoxy sulfate, polyoxyethylene alkyl phenyl ether sulfate, dialkyl sulfosuccinate acid ester salt, alkyl phosphate ester acid,
Sulfuric ester acid of fatty acid alkylolamide,
naphthalene sulfonic acid sodium formalin condensate,
Examples include polyoxyethylene alkyl phosphate. Cationic surfactants include various quaternary ammonium salts, and amphoteric surfactants include N-acyl (having 8 to 18 carbon atoms) zarconates, alkylglycine types, betaine types, and imidazolines. Examples include type, carboxylic acid type, alanine type, and sulfate ester type. In the present invention, nonionic surfactants are preferably used, and glycerin fatty acid esters are particularly preferred. In the present invention, one type of the various surfactants as described above may be used alone, or two or more types may be optionally used in combination. The blending amount of these surfactants in the present invention is 100 parts by weight of the resin constituting the antistatic layer (hereinafter referred to as
It is simply called "department". ), preferably 0.05 to 0.5 parts. The antistatic layer 1 has the above-mentioned composition and is made into a film by extrusion molding, calendar molding, etc. However, from the viewpoint of workability, efficiency, etc., the antistatic layer 1 is coextruded with the barrier layer 2 described later. It is preferable to mold them in a laminated state by coextrusion inflation molding or the like. For the barrier layer 2, the same polyolefin as used for forming the antistatic layer 1 described above is optionally used, and the barrier layer 2 does not contain an antistatic agent. The above-mentioned antistatic layer 1 is provided on one side of this barrier layer 2, and the conductive layer 3, which will be described later, is provided on the other side. In this way, the barrier layer 2 is provided to separate the antistatic layer 1 and the conductive layer 3, and this is because the antistatic agent contained in the antistatic layer 1 oozes out (bleeds out) over time. ), and for example, if a conductive layer 3 (described later) is provided directly on the antistatic layer 1, the adhesion between the antistatic layer 1 and the conductive layer 3 will be poor due to oozing of the antistatic agent, and the conductive layer 3 will peel off. . The barrier layer 2 prevents such an antistatic agent from seeping out to the conductive layer 3 side, and provides reliable and stable bonding of the conductive layer 3. The conductive layer 3 may be made of any material as long as it has excellent transparency, but for example, a fine conductive material made of white powder-like tin oxide as the main component mixed with antimony or isodium oxide, etc. can be used. It is made into a powder and mixed with a paint made by dissolving polyurethane, epoxy, polyester, polycarbonate, vinyl, acrylic, or other resins in a solvent such as ether, ester, ketone, or alcohol to make a conductive paint. The conductive layer 3 is preferably formed on one surface of the barrier layer 2 by coating and drying. When forming the conductive layer 3, since the barrier layer 2 is made of polyolefin, there may be problems with adhesion if it is simply coated, but in that case, the conductive layer 3 of the barrier layer 2 is provided. The surface may be subjected to a corona discharge treatment, an adhesion promoter 4 may be provided, or a combination of these may be used. The degree of treatment when applying corona discharge treatment varies slightly depending on the composition of the barrier layer 2, etc.
Approximately, wetting tension of the treated surface when corona discharge treatment is applied and left for about a week (JIS-K-6768-1971
(according to ) is preferably 34−42 dyne/cm,
If the wetting tension is less than 34 dyne/cm, no improvement in adhesion can be expected, and if it is more than 42 dyne/cm, excessive processing will occur and the physical properties of the film will deteriorate. A conductive layer 3 may be formed by direct coating on the barrier layer 2 which has been subjected to corona discharge treatment, but in order to ensure more secure adhesion, it is preferable to provide an adhesion promoter (anchor coat layer) 4. . As the adhesion promoter layer 4, an adhesion promoter that is normally used for bonding polyolefin and other materials is used. Examples of adhesion promoters include urethane anchor coating agents containing tolylene diisocyanate, polyol, etc. as main components, organic compounds containing alkoxy titanium esters as main components, such as isopropyl titanate, butyl titanate monomer, butyl titanate dimer, stearyl titanate, etc. Titanate type, polyethyleneimine type, etc. are used. It is sufficient to apply the adhesion promoter 4 to the surface of the barrier layer 2 at a rate of 1 to 20 g/m ² using a roll coater or the like, and it is desirable to dry it after application in terms of adhesion. The transparent conductive film of the present invention thus obtained has an antistatic layer 1, a conductive layer 3, and a barrier layer 2.
The synergistic effect of the antistatic effect of the antistatic layer 1 and the conductive effect of the conductive layer 3 makes it an extremely suitable material for packaging materials such as electronic devices. The thickness structure of the antistatic layer 1, barrier layer 2, and conductive layer 3 is determined based on the desired antistatic effect, film strength,
Although it varies depending on the conductivity etc., the antistatic layer 1 is usually
10-50μ, barrier layer 2 is 10-150μ, conductive layer 3 is
It is estimated to be about 0.2 to 10μ. The antistatic layer 1 preferably has an antistatic agent having a surface resistivity of about 1×10 ⁹ to 1×10 ¹² Ω/cm ² , and the conductive layer 3 preferably has a surface resistivity of about 1×10 9 to 1×10 12 Ω/cm 2 . It is desirable that the conductivity is 1×10 ⁸ Ω/cm ³ or less. Examples will be shown below, and one example of the film of the present invention will be explained in more detail, but the present invention is not limited to the following examples unless the gist thereof is exceeded. Example 1 Low density polyethylene (manufactured by Mitsubishi Chemical Industries, Ltd., Novatec L-F155, density (ρ): 0.925 g/cm ³ , melt index (MI): 2.0 g/10 min, flow ratio (FR): 34, Melt tension (MT): 5.0
g, molecular weight distribution index (α): 320) (Novatek is a registered trademark of Mitsubishi Chemical Industries, Ltd.). The antistatic layer resin contains the above low-density polyethylene, antistatic agent lauryl diethanolamine: 2000 ppm, and alkyl fatty acid ester:
1000 ppm was added and mixed, and the above low density polyethylene was used as it was as the resin for the barrier layer. Both resins were co-extruded in two layers using an inflation molding machine (L-50 type extruder manufactured by Plako Co., Ltd. and VSE40 type extruder manufactured by Osaka Seiki Co., Ltd. connected to a 120φ 2-type 2-layer die manufactured by Osaka Seiki Co., Ltd.) at a resin temperature of 170°C. Blow up ratio 1.5
A cylindrical film with a thickness of 50 μm (antistatic layer thickness 20 μm, barrier layer thickness 30 μm) was obtained. The cylindrical film released from the inflation molding machine was cut open, the barrier layer side was subjected to corona discharge treatment, and the obtained film was wound up. The processing amount of corona discharge treatment is the wetting tension measured after leaving it for one week after corona discharge treatment.
It was 42dyne/cm. Tolylene diisocyanate-based anchor coating agent {Coronate L (product name), manufactured by Nippon Polyurethane Co., Ltd.}
and polyol-based anchor coating agent {Desmofene 800 (trade name) manufactured by Nippon Polyurethane Co., Ltd.} at 2:
1, and added the same volume of toluene/ethyl acetate mixture in 4/1 to make a double diluted liquid, which was applied to the surface of the corona discharge-treated film using a dry laminator, and the temperature was set at 80°C. Dry in oven for 5 seconds. The resulting anchor coat layer had a coating weight of 20 g/m ² . A paint (solid content: 30% by weight) in which a mixture of 65 parts by weight of a finely mixed powder of tin oxide and antimony trioxide (9:1 ratio) and 35 parts by weight of a polyester binder is dispersed in a solvent is applied as a bar on the anchor coat. It was applied with a coater and dried. The thickness of the conductive layer was 10μ. The transparency of the obtained conductive film, the adhesion of the conductive layer, the surface resistivity of the antistatic layer, and the surface resistivity of the conductive layer were measured, and the results are shown in Table 1. Transparency was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd.)
This is the value measured using an NDH20 type haze meter). Adhesion was measured by applying cellophane tape with a width of 24 mm and length of 100 mm using finger pressure and observing the degree of peeling when peeled off by hand.The amount of peeling of the conductive layer from the entire surface of the tape was 20% or less. Cases were marked as ○, and cases above were marked as ×. The surface resistivity was measured using a surface resistivity measurement electrode (manufactured by Ando Electric Co., Ltd., SE100) under a constant temperature of 20°C and 65% humidity.
The antistatic layer was measured using an insulation resistance meter (super insulation resistance meter, manufactured by Ando Electric Co., Ltd.) for the antistatic layer.
VMG-100 type). Example 2 Using the low density polyethylene used in Example 1,
A conductive layer film was obtained in the same manner as in Example 1, except that the anchor coating agent was diluted 30 times and the coating amount was 3 g/m ² , and the coating amount of the conductive layer paint was changed to give a film thickness of 1 μm. Table 1 shows the measured values of various physical properties. Example 3 Instead of the low density polyethylene used in Example 2,
Low-density polyethylene (manufactured by Mitsubishi Chemical Industries, Ltd., Novatec L-F531, ρ: 0.927 g/cm ³ , MI: 1.3 g/
A conductive film was obtained in the same manner as in Example 2, except that FR: 32, MT: 6.9 g, α: 287) was used. Table 1 shows the measured values of various physical properties. Example 4 An organic titanate-based anchor coating agent was used in place of the anchor coating agent used in Example 3 {Mitsubishi Kosikagaku Co., Ltd.
AC-771} to 1/1 of toluene/n-hexane.
A conductive layer film was obtained in the same manner as in Example 3 except that a solution diluted 30 times was used. Table 1 shows the measured values of various physical properties. Example 5 In place of the low density polyethylene used in Example 3,
Linear low density polyethylene (ρ: 0.918g/cm ³ ,
MI: 1.0g/10min, FR: 18, MT: 2g, α:
A conductive film was obtained in the same manner as in Example 3 except that 36) was used. Table 1 shows the measured values of various physical properties.

[Table] As described above, the transparent conductive film of the present invention has excellent transparency, so it is possible to check the contents even when electronic parts are packaged, which is convenient for product management. Since it is a laminate of a prevention layer and a conductive layer, it is an extremely excellent conductive layer that combines the effects of the conductive layer to prevent damage to electronic components, and the antistatic layer's effects to prevent static electricity generation and dust adhesion. It has become a film. Furthermore, since a barrier layer is formed between the antistatic layer and the conductive layer, the antistatic agent in the antistatic layer does not reduce the adhesion of the conductive layer, so it can be used for a long time. The practical effects are extremely large, such as that it is possible. Note that the transparent conductive film of the present invention is not only used for packaging electronic components as described above, but can also be applied to various uses such as electromagnetic wave absorbing materials for preventing radio wave interference.

[Brief explanation of drawings]

1 and 2 are longitudinal sections of the film of the present invention. In the figure, 1 is an antistatic layer, 2 is a barrier layer, 3 is a conductive layer, and 4 is an adhesion promoter layer.

Claims (1)

[Claims] 1. An antistatic layer made of polyolefin containing an antistatic agent is provided on one side of a barrier layer made of polyolefin not containing an antistatic agent, and a transparent conductive layer is provided on the other side of the barrier layer via an adhesion promoter layer. The adhesion promoter layer is made of a urethane-based, organic titanate-based, or polyethyleneimine-based adhesion promoter, and the conductive layer is made of a conductive material mainly containing tin oxide. A transparent conductive film comprising a coating film formed by applying a paint containing.