JPS63317333A - Conductive film - Google Patents

Abstract

PURPOSE:To obtain a conductive film, high in adhesive property between a base film and a conductive layer and excellent in durability, by a method wherein a layer, consisting of a composite having the principal constituent of polyurethane, acrylic resin, fatty amide or bis-amide, is provided between the base film and the conductive layer. CONSTITUTION:In a conductive film, in which a conductive layer is formed on a base film consisting of a polymeric film, a layer, consisting of a composite having the principal constituent of polyurethane A, acrylic resin B, fatty amide or bis-amide C, is provided between the base film and the conductive layer. The polyurethane resin A, is aqueous polyurethane and the acrylic resin B contains 40-80mol.% of methyl methacrylate constituent and 20-60mol.% of other vinyl monomer constituent, capable of being co-polymerized with the methyl methacrylate constituent. In this conductive film, adhesive property between the base film and the conductive layer is high, therefore, the practical durability of the title film may be improved remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a conductive film with improved adhesion between a base film and a conductive layer.

<Prior art> Conventionally, Nesa Glass, which is a material in which a conductive layer is formed on a material such as glass or quartz, is known, and is used as electrodes for displays such as liquid crystal, EL, and electrochromic, electrodes for solar cells, and antistatic.

It was used as an EMI shielding material.

However, since the base material is glass or the like, it has the disadvantage of being inferior in flexibility, workability, and impact resistance.

In recent years, conductive films, especially transparent conductive films, in which a polymer film is used as a base material and a conductive layer is formed thereon, have been attracting attention. It is used as an electrode for EL, electrochromic, and other displays, and demand is expected to increase in the future.

However, conductive films do not have sufficient adhesion between the base film and the conductive layer, and when used as the electrode, the base film and conductive layer peel off during use. However, there was a problem of decreased durability.

(Problems to be Solved by the Invention) The present invention has been made in view of the above problems, and provides a conductive film that has high adhesion between the base film and the conductive layer and has excellent practical durability. It is.

<Means for Solving the Problems> That is, the present invention provides the above-mentioned conductive film, in which polyurethane (A), polyurethane (A),
Acrylic resin (B), fatty acid amide or bisamide (
It is a conductive film having a layer made of a composition containing C) as a main component.

Examples of the polymer film of the base film used in the present invention include polyester, polyethylene, polyimide, polybonate, polyvinyl chloride, polyvinyl fluoride, and polysulfone.

Acrylic, polypropylene, polyether sulfone, polyether ketone, nitrile phenol, etc. can be used. Usually, polyester is preferably used because of its dimensional stability, mechanical strength, and cost.

Regarding electrical conductivity, the following items are considered: (1) Thin films of metals such as gold, silver, palladium, and aluminum (2) Thin films containing copper iodide, indium oxide, tin oxide, titanium Mide, cadmium oxide, etc. as main components. Thin films of metal compounds are known. Although any of these can be used in the present invention, the effect of the present invention is greatest when indium oxide is doped with 2 to 20 wt % of tin oxide.

The thickness of these conductive layers varies depending on the intended use, but is usually 1! In terms of conductivity, transparency, productivity, etc., 100 to 500^ is recommended for electrodes, and 2 is used for antistatic purposes.
0 to 200 people.

These conductive layers are formed by conventionally known methods such as physical vapor deposition. Usually, vacuum R cash on delivery.

Sputtering method and ion blating method are preferably used.

The layer for enhancing adhesion (hereinafter referred to as "adhesion layer") formed between the base film of the present invention and the S-electroconductive layer can be formed during the film formation of the base film or once the film formation is completed. processed into a film. In-line processing, which is performed during the production of the base film, is preferred from the viewpoint of preventing the adhesion of foreign substances such as dust and productivity.

For example, in the case of a polyester film, polyester resin is melt-extruded into a plate shape, formed into a film using a conventional method, an adhesive layer is applied to one side of the film before crystal orientation is completed, and then drying, stretching, and heat treatment are performed. By completing the crystal orientation, a base film with an adhesive layer can be obtained.

The polyurethane of the component (A) of the adhesive layer of the present invention is preferably a water-based polyurethane, and the water-based polyurethane is preferably one whose affinity for water is increased by a carboxylic acid group, a sulfonic acid group, or a sulfuric acid half-ester base. Such a water affinity-imparting group is usually introduced during or after polyurethane synthesis.

For example, a carboxylic acid group can be introduced by using a carboxylic acid group-containing polyhydroxy compound as one of the raw material poly and droxy compounds during polyurethane synthesis, or by introducing a hydroxyl group-containing carboxylic acid group into the isocyanate group of a polyurethane having unreacted isocyanate groups. This can be carried out by reacting an amino group-containing carboxylic acid, then adding the reaction product to an alkaline aqueous solution under high speed stirring, and neutralizing it.

In addition, the introduction of a sulfonic acid group or a sulfuric acid half-ester base is usually carried out by forming a prepolymer from a polyhydroxy compound, a polyisocyanate, and a chain extender, and adding an amino group or a hydroxyl group that can react with the terminal isocyanate group and a sulfonic acid group or This can be carried out by adding and reacting a compound having a sulfuric acid half ester base in its molecule, and finally obtaining an aqueous polyurethane having a sulfonic acid group or a sulfuric acid half ester base in its molecule. In this case, it is preferable to carry out the formation reaction in an organic solvent, then add water and then remove the solvent. Moreover, in Haku's method, a polyurethane having a sulfonic acid group is synthesized using a compound having a sulfonic acid group as one of the raw materials, and then the polyurethane is added to an alkaline aqueous solution under high speed stirring.
Method of neutralizing primary or secondary polyurethane main chain or side chain
Examples include a method in which an alkali sulfonic acid salt (for example, -8O3Na, etc.) is introduced by adding the following sultone compound to a class amino group in the presence of an alkali.

As the alkaline aqueous solution, it is preferable to use an aqueous solution of sodium hydroxide, potassium hydroxide, ammonia, alkylamine, etc., but the alkali does not remain in the coating film (undercoating film), such as ammonia and amines that volatilize under drying conditions. Particularly preferred.

The amount of bases such as carboxylic acid bases, sulfonic acid bases, and sulfuric acid half ester bases is preferably 0.5 to 15% by weight. If the proportion of the base is too small, the water affinity of the polyurethane will be insufficient, making it difficult to prepare a coating solution, and if it is too large, the inherent properties of the polyurethane will be impaired, which is not preferable. Such aqueous polyurethane forms a stable aqueous dispersion or aqueous solution using a dispersion aid if desired.

Examples of polyhydroxy compounds used in the synthesis of polyurethane include polyethylene glycol.

Polypropylene glycol, polyethylene propylene glycol, polytetramethylene glycol, hexamethylene glycol, tetramethylene glycol, 1,5
-bentanediol, diethylene glycol, triethylene glycol, polycaprolactone, polyhexamethylene adipate.

Polyhexamethylene sebacate, polytetramethylene adipate, polytetramethylene sebacate.

Trimethylolpropane, trimethylolethane.

Examples include pentaerythritol and glycerin.

Examples of the polyisocyanate compound include hexamethylene diisocyanate, diphenylmethane diisocyanate, and tolylene diisocyanate.

Examples include isophorone diisocyanate, an adduct of tolylene diisocyanate and trimethylolpropane, and an adduct of hexamethylene diisocyanate and trimethylolethane. Examples of the carboxylic acid-containing polyol include dimethylolpropionic acid, dimethylolbutyric acid, dimethylolvaleric acid, and trimellitic acid bis(ethylene glycol) ester.

Examples of amino acid-containing carboxylic acids include β-aminopropionic acid, γ-aminobutyroif1. Examples include P-aminobenzoic acid. Examples of the hydroxyl group-containing carboxylic acid include 3-hydroxypropionic acid, γ-hydroxybutyric acid, P-(2-hydroxyethyl)benzoic acid, and malic acid.

Examples of compounds having an amino group or a hydroxyl group and a sulfonic group include aminomethanesulfonic acid.

Examples include 2-aminoethanesulfonic acid, 2-amino-5-methylbenzene-2-sulfonic acid, sodium β-hydroxyethanesulfonate, propane sultone and butane sultone addition products of aliphatic diprimary amine compounds, etc. Preferred examples include propane sultone adducts of aliphatic diprimary amine compounds.

Examples of compounds containing an amine group or a hydroxyl group and a sulfuric acid half ester include aminoethanol 5AM, ethylenediamineethanol sulfate, aminobutanol sulfate, and hydroxyethanol sulfate.

Examples include γ-hydroxypropanol sulfate and α-hydroxybutanol sulfate.

Polyurethane can be synthesized using these compounds by conventionally well-known methods.

Next, as the acrylic resin as the component (B) of the adhesive layer of the present invention, the methyl methacrylate component ranges from 40 to 40.
Preferably, the aqueous acrylic resin contains 80 mol % of the vinyl monomer component and 20 to 60 mol % of other vinyl monomer components copolymerizable therewith.

The methyl methacrylate component in the above acrylic resin is 40%
If it is less than mol%, the coating film tends to decrease in strength and become soft,
This is undesirable due to the deterioration of handling properties due to deterioration of blocking resistance. On the other hand, the methyl methacrylate component is 80%
If the amount exceeds mol %, the coating film tends to harden and become brittle, and furthermore, the adhesion to the base material decreases and the film forming property is deteriorated, which is not preferable.

Other vinyl monomers (copolymerizable monomers) that can be copolymerized with methyl methacrylate, which is a component of acrylic resins.
Examples include alkyl acrylate (alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.): Alkyl methacrylate (the alkyl group is one exemplified as the alkyl group of the above-mentioned alkyl acrylate, excluding the methyl group): 2-hydroxyethyl acrylate, 2-
Hydroxy-containing monomers such as hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, etc. Niacrylamide, methacrylamide, N-methylmethacrylamide, N
-Methylacrylamide, N-methylol acrylamide, N-methylol methacrylamide.

Amide group-containing monomers such as N,N-dimethylolacrylamide, N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, N-phenylacrylamide; N,N-diethylaminoethyl acrylate, N,N-diethylaminoethyl methacrylate, etc. Amino group-containing monomers such as: glycidyl acrylate,
Boxy group-containing monomers such as glycidyl methacrylate, allyl glycidyl ether, etc. Containing sulfonic acid groups or their salts such as styrene sulfonic acid, vinyl sulfonic acid, and their salts (sodium salt, potassium salt, ammonium salt, etc.) Monomers: Monomers containing carboxyl groups or salts thereof such as crotonic acid, itaconic acid, acrylic acid, maleic acid, fumaric acid and their salts (sodium salts, potassium salts, ammonium salts, etc.): Fomaleic anhydride, itaconic anhydride Monomers containing acid anhydrides such as acids; others, vinyl isocyanate, allyl isocyanate, styrene, vinyl methyl ether, vinyl ethyl ether, vinyl tris alkoxysilane, alkyl maleic acid monoester, alkyl fumaric acid monoester.

Examples include acrylonitrile, methacrylonitrile, alkyl itaconic acid monoester, vinylidene chloride, vinyl acetate, and vinyl chloride.

These copolymerizable monomers can be freely selected singly or in combination of two or more, but from the viewpoint of imparting hydrophilicity to the acrylic resin, dispersion stability of the aqueous liquid, adhesion to the base material, etc., hydroxyl groups, amide groups, etc. Those having a functional group such as a carboxyl group or a salt thereof (sodium salt, potassium salt, ammonium salt, etc.) are preferable.

In addition, thermosetting types are suitable for improving the heat resistance 1 strength, water resistance, etc. of coating films. For example, epoxy group-containing monomers and amino groups, acid anhydride groups, carboxyl groups, human oxygen groups or N - Combination with a monomer containing a methylol group: Examples include a combination of a monomer containing an N-methylol or N-methylol ether group and a monomer containing a carboxyl group or an amino group. It also includes cases where it has thermosetting properties even when used alone. One type or a combination of two or more of these reactive groups can be optionally introduced into one type of acrylic resin or two or more types of acrylic resins, and if necessary, groups that can react with each other during heating may be introduced. A combination of acrylic resins having the following properties may be used. Furthermore, one or more types of low-molecular weight substances (eg, alkylolated melamine, etc.) having groups that can react with the reactive groups in the acrylic resin when heated can also be added.

The aqueous liquid of acrylic resin can be produced by any known method. For example, to illustrate an emulsion polymerization method in an aqueous dispersion system, one polymerization of an emulsifying dispersant (a surfactant such as sodium dodecylbenzenesulfonate) and a water-soluble polymerization initiator (a peroxide such as ammonium persulfate) is carried out in ion-exchanged water. Add an appropriate amount of accelerator (reducing agent such as acidic sodium sulfite),
Approximately 10-50% of a given amount of monomer is added at a given temperature (e.g. 50-90°C) and with stirring at a given stirring speed.
When polymerization has started, the addition is interrupted for a short time, and the remaining 70% is added at a constant rate.
An aqueous dispersion of acrylic resin can be produced by emulsion polymerization under the same conditions for several hours.

The amount of the surfactant used in the above reaction is preferably 5% by weight or less, preferably 1 to 2% by weight based on the copolymerization monomer component, and the surfactant has a fine particle size of 0.2 μm or less in terms of average particle size. is obtained. Incidentally, if necessary, a molecular i'a conditioner (for example, mercaptans), a dispersion aid (for example, polyvinyl alcohol, polymeric protective colloids such as hydroxymethylcellulose), etc. may be added.

In addition, applications of high molecular weight surfactants in place of the above-mentioned low molecular weight surfactants; applications of zero-reactive surfactants;

A production method using so-called soap-free polymerization that does not contain a surfactant may also be adopted.

Next, as the fatty acid amide or bisamide of the component (C) of the adhesive layer of the present invention, an amide of a saturated or unsaturated fatty acid having 6 to 22 carbon atoms, a molecule ffl having 13 to 50 carbon atoms,
200 to 800 N,N'-alkylene bisamide and the like are preferably mentioned. More specifically, N, N'
-methylenebis-stearamide, N,N'-ethylenebispalmitic acid amide.

Examples include N,N'-methylenebislauric acid amide, linoleic acid amide, caprylic acid amide, and stearic acid amide. Among these, bisamides represented by the following formula % (where RCO-: fatty acid residue, n=1 or 2) are particularly preferred.

These fatty acid amides or bisamides can be dissolved in a specific solvent or used in the form of an aqueous liquid as an emulsion or suspension. In this case, an emulsifier or a surfactant may be used.

In the present invention, an aqueous solution, dispersion, or emulsion of the above-mentioned polyurethane (A), acrylic resin (B), and fatty acid amide or bisamide (C) is used. A surface roughening substance (D) may be mixed into the surface roughening substance (D).

The roughening substance (D) is polystyrene, polymethyl methacrylate, methyl methacrylate copolymer, polytetrafluoroethylene, polyvinylidene fluoride or polyacrylonitrile.

Organic fine powder such as benzoguanamine resin, or silica, alumina, titanium dioxide, kaolin.

Talc, graphite, calcium carbonate, feldspar.

Examples include fine inorganic powders such as molybdenum disulfide, carbon black, or barium sulfate, which may be made into an aqueous dispersion using an emulsifier or the like; It may be one that can be added to an aqueous resin solution, a fatty acid amide or bisamide aqueous solution, or the like.

This surface roughening substance (D) is fine particles with an average particle size of 0.15 μm or less, preferably 0.01 to 0.1 μm.

Furthermore, in order to avoid sedimentation of these surface roughening substances (D) in the aqueous dispersion, it is preferable to select ultrafine particles whose specific gravity does not exceed 3.

Polyurethane (A), acrylic resin (B), fatty acid amide or bisamide (C) which is the main component of the adhesive layer of the present invention
The mixing ratio of is usually [(A)+(B)]/(C)=
98/2~40/60 (A)/(B) = 9
It is preferably in the range of 0/10 to 10/90 (solid content exchange sieve: 1% by weight). In addition, when mixing the surface roughening substance (D), the mixing ratio is [(A>+(B)+(C)]/
(D) is preferably in the range of 98/2 to 40/60.

If the mixing ratio of acrylic resin <8), fatty acid amide or bisamide (C) is too small, the frictional force will increase,
Handling properties are deteriorated, and if the amount is too large, the adhesion to the base film is reduced and the slipperiness of the film is reduced.

In the present invention, in order to be able to smoothly coat the adhesive layer on the surface of the base film, the film surface is subjected to colloidal discharge treatment as a preliminary treatment, or it is chemically incompatible with the composition of the adhesive layer. It is preferable to use an active surfactant in combination.

Such surfactants lower the surface tension of the aqueous composition by 40 dy.
It promotes wetting of polymer films such as polyester films that can drop to below ne/cm, and includes, for example, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, Examples include anionic and nonionic surfactants such as fatty acid metal soaps, alkyl sulfates, alkyl sulfonates, and alkyl sulfosuccinates. Furthermore, antistatic agents, for example, may be used within a range that does not impair the effects of the present invention.

Other additives such as UV absorbers, lubricants, etc. can be mixed.

In the present invention, the aqueous liquid thus prepared is preferably applied to at least one side of the polyester film, etc., before the crystal orientation is completed, as described above. The solid content concentration of the aqueous liquid at that time is less than the usual 30% by weight,
It is preferably 15% by weight or less. Viscosity is less than 100 cps,
Preferably, 20 cps or less is appropriate. The coating amount is preferably about 0.5 to 209 g, more preferably 1 to 10 g, per 1'rrL of the running film. In other words, in the base film finally obtained, the solid content is preferably about 0.001 to 1 g, more preferably about 0.01 to 0.3 g per surface of the film.

Any known coating method can be used as the coating method.

For example, roll coating method, gravure coating method, roll plush method, spray coating method, air knife coating method,
It is preferable to apply an impregnation method, a curtain coating method, etc. alone or in combination.

In the present invention, in the case of polyester, it is particularly preferred that the aqueous liquid is applied to the film immediately after longitudinal-axial stretching, and then the film is introduced into a tenter for transverse stretching and heat-setting.

The area of the coated product is expanded as the film is stretched in an unsolidified state, and is heated to volatilize water and firmly adhere to the surface of the two-wheel oriented film.

This heating is preferably performed at a temperature of about 100 to about 240'C for about 1 to about 20 seconds.

<Effects> Since the conductive film of the present invention has high adhesion between the base film and the conductive layer, its practical durability is significantly improved.

Therefore, it is widely applicable as described below. In particular, it is clear from the examples that the keystroke life, which is the most important quality of a touch panel described below, has been significantly improved.

Among these conductive films, transparent ones are used for applications that utilize the interaction of light and electric fields, such as transparent touch panels; solid-state light emitting devices, photoelectric conversion devices, facsimile recording media, EL displays, liquid crystal displays, and electrochromic displays. Used as a base material for electrophotography such as Nislide film and microfilm. Also, windshields and signal lights of cars, airplanes, and other vehicles.

Heating element to prevent condensation and freezing in frozen showcases, etc.

It is also used as a base material for thermoplastic recording, photochromic memory, amorphous semiconductor memory, etc. Furthermore, it is a matter of course that it can be used for anti-static purposes such as meter windows and work mats for cathode ray tubes, and as a selective light transmission film for quick start of fluorescent lamps.

Example 1 (1) Polyurethane aqueous dispersion having a carboxylic acid amine base [manufactured by Toyo Polymer ■: trade name Merci 585]
28 parts (as non-volatile components), 28 parts of acrylic resin emulsion [methyl methacrylate/ethyl acrylate/acrylamide = 49/43/8 (mol%)], 7 parts of methylene bis stearamide, colloidal silica aqueous dispersion (average A coating liquid having a solid content concentration of 2% by weight was prepared by diluting and dissolving 27 parts of polyoxyethylene nonyl phenyl ether [NOF [7: trade name N8208.

('2J) Molten polyethylene terephthalate was extruded from a die using an extruder, and the unstretched film, which had been rapidly cooled on a casting drum, was stretched 3.6 times in the longitudinal direction on a heated metal roll.

The coating liquid prepared in (1) above was uniformly applied onto one side of this film by a kiss coating method.

The average coating amount at this time was approximately 49 wet per 1Td of the above-mentioned -axially oriented film (this amount corresponds to approximately 0.029 per 1TIi for the biaxially oriented film described below). A uniaxially stretched film coated on one side is introduced into a tenter, passed through a preheating zone at 98°C, stretched 3.9 times in the transverse direction at 105°C, and then heat-set at 225°C for 6.3 seconds. The total time the film was heated corresponds to 11 seconds).

(3) The film thus obtained with a thickness of 75 μm was fixed on a substrate holder in a DC magnetron sputtering device, and the vacuum chamber was evacuated until the pressure reached 1×10′5 Torr. After that, Ar102 mixed gas (0225
%) into the vacuum chamber, and the pressure was increased to 4x 10' To
After maintaining the temperature at rr, a tin-doped indium oxide (ITO) film was formed by reactive sputtering using a target made of in/Sn alloy (5 wt % Sn) at a deposition rate of about 1000 people/7 ml. ITO film thickness is 200
It was a person. The characteristics of the sample were a light transmittance of 86% at a wavelength of 550 nm and a surface electrical resistance of 450 Ω/hole.

(4) A transparent switch was prepared using the conductive film obtained in (3) above, with the ITO film surfaces facing each other with a spacer at intervals of 100 μm, and the durability was evaluated as follows.

Silicone rubber rod with 7R tip (weight 200g)
is continuously free-falling onto a transparent switch using a solenoid at a frequency of 3Hz>.

Each time the rod fell, the switch was pressed and 1 mA was applied to the switch by a constant current power supply. The life of the switch was investigated by observing the pulse-like waveform when the transparent switch was pressed using a synchroscope. When the switch life was defined as the number of presses when the pulse-like waveform was no longer observed, the switch life was 1.2 million times.

Similarly, regarding the conductive film obtained in (3),
One side of the ITOg was bonded to a 100 μm thick aluminum plate using an epoxy adhesive, and the adhesive was cured by heat treatment at 80° C. for 5 minutes.

Subsequently, it was attached to a predetermined position in a tensile testing machine and a 180 degree peel test was conducted (peel rate: 10 IJ/1n). The force per width of the sample I atr observed during peeling is expressed as I
When the adhesion force between the TO film and the base film was defined as <9/cm>, the adhesion force was 4809/an.

Comparative Example 1 In Example 1, the coating solution of (1) was introduced into a tenter without being applied, and a 75 μm film without an adhesive layer was stretched and heat-treated in the same manner as in Example 1.

An ITO film having a thickness of 200 was formed in the same manner as in Example 1 to produce a conductive film having a light transmittance of 84% and a surface electrical resistance of 520 Ω/hole.

The life of the conductive film switches thus obtained is 2.
50,000 times or less, and ITO in the 180 degree peel test
The adhesion between the membrane and the base film was 290 g/'α.

Patent Applicant Teijin Ltd. Mae'1, '4 Agent Patent Attorney Former 1) Jun Hiroshi 1
・′〜＼、−

Claims (1)

[Claims] 1. In a conductive film in which a conductive layer is formed on a base film made of a polymer film, polyurethane (A), acrylic-based A conductive film characterized by having a layer made of a composition whose main components are a resin (B), a fatty acid amide, or a bisamide (C). 2. The conductive film according to claim 1, wherein the polyurethane (A) is an aqueous polyurethane. 3. The claim that the acrylic resin (B) is an aqueous acrylic resin containing 40 to 80 mol% of a methyl methacrylate component and 20 to 60 mol% of other vinyl monomer components copolymerizable therewith. The conductive film according to item 1. 4. The conductive film according to any one of claims 1 to 3, wherein the layer made of the composition contains a surface roughening substance (D). 5. The conductive film according to any one of claims 1 to 4, wherein the conductive layer is a metal thin film or a metal compound thin film. 6. The conductive film according to claim 5, wherein the conductive layer is transparent. 7. The conductive layer is made of tin-doped indium oxide (IT
O) The conductive film according to claim 6, which is a thin film.