JP2572762B2 - Conductive film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a conductive film.

[Conventional technology]

In recent years, thermal transfer recording has attracted attention in the fields of electronic computers, facsimile machines, etc. because it is non-impact, noiseless, low-cost, and can be reduced in size and weight. This is the most promising method.

In general, the energization transfer recording method is such that an energization head comprising a current recording electrode and a return electrode is pressed into contact with an energization transfer recording material comprising a resistance layer, a conductive layer, an ink layer, and the like, and energization is performed to generate heat in the resistance layer and raise the temperature. When the ink is heated, the heat is transmitted to the conductive layer, the temperature of the ink layer rises, and the ink layer melts and flows, thereby being transferred and recorded on the recording material.

In such an energization transfer recording method, since the resistance layer generates heat when energized, it is important to properly set the resistance value of the resistance layer. Conventionally, a conductive carbon black is dispersed in a polycarbonate resin to form the resistance layer. (JP-A-54-87234) and a method of forming a resistance layer by dispersing 3 to 30% by weight of carbon black in a polyamide resin such as nylon-6 (JP-A-59-120494). It has been known.

[Problems to be solved by the invention]

However, a resistance layer formed by a conventional method, for example, a resistance layer in which a conductive carbon black is blended in a polycarbonate resin, has a low tensile strength and tear strength and is not yet sufficient.

In addition, although the resistance layer in which carbon black is blended with nylon-6 or the like is improved in tensile strength and tear strength immediately after formation compared to the polycarbonate resin in which carbon black is blended, it gradually absorbs moisture under use environment conditions, Tensile strength and dimensional stability deteriorate significantly. Further, since the glass transition point is lower than that of the polycarbonate resin, there is a problem that heat resistance is inferior and the like, and improvement has been desired.

[Means for solving the problem]

Therefore, the present inventors have conducted intensive studies to solve the conventional problems, and as a result, by using a resistance layer in which a specific polyamide resin is blended with a specific carbon black, the same heat resistance as that of a polycarbonate resin is maintained, and the tensile strength is further increased. The strength and tear strength are significantly better than the resistance layer made of polycarbonate resin blended with carbon black, and even when used in a normal humidity environment, the tensile strength decreases and the dimensional stability deteriorates like polyamide resin such as nylon-6. Nothing was found, and based on this, the conductive film of the present invention was reached.

That is, an object of the present invention is to improve the mechanical strength, which is a drawback of a conductive film made of a polycarbonate resin, and to deteriorate the strength and dimensional stability due to moisture absorption, which is a drawback of a polyamide resin such as nylon-6, and to further improve heat resistance. An object of the present invention is to provide an excellent conductive film in which the above is improved.

The purpose is to achieve a pore volume of 2.5 cc / g or less according to the mercury porosimeter method, the maximum peak position of the pore distribution according to the mercury porosimeter method is 200 mm or more, and the DBP
Carbon black having an absorption amount of 20 to 250 ml / 100 g, and one of which is obtained by a polycondensation reaction using one or more diamines and one or more dicarboxylic acids having one or more aromatic rings in the molecule as a starting material. It is easily achieved by a conductive film characterized by being made of an amorphous polyamide resin having a ring.

 Hereinafter, the present invention will be described in detail.

The amorphous polyamide having an aromatic ring in the molecule referred to in the present invention is one or more diamines and one or more dicarboxylic acids, but any one having an aromatic ring in the molecule and a lactam if necessary. A polyamide resin obtained by a polycondensation reaction as a starting material.When measured by a differential scanning calorimeter, the resin once melted is quenched with liquid nitrogen and then cooled.
A polyamide resin having a heat of fusion of 1 cal / g or less when the temperature is raised again at ° C / min.

Diamines as raw materials for such polyamide resins include butylenediamine, hexamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4
-/ 2,4,4-trimethylhexamethylenediamine, metaxylenediamine, paraxylenediamine, paraaminocyclohexylmethane, bis (3-methyl-4-aminocyclohexyl) methane, 1,3-bis (aminomethyl) cyclohexane, 1 1,4-bis (aminomethyl) cyclohexane, bis (4-aminocyclohexyl) methane, isophoronediamine, and the like can be used.

Further, as a dicarboxylic acid as a raw material of such a polyamide resin, adipic acid, sebacic acid, isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid and the like can be used.

Further, as a lactam used as a raw material of such a polyamide resin, ε-caprolactam, ω-laurolactam and the like can be used.

Among the many polyamides composed of the above raw materials, those belonging to the amorphous polyamide resin having an aromatic ring in the molecule referred to in the present invention include hexamethylenediamine, isophthalic acid, and terephthalic acid (provided that isophthalic acid / terephthalic acid> 2/1 (molar ratio)), polyamide resin consisting of 2,2,4- / 2,4,4-trimethylhexamethylenediamine and terephthalic acid and / or isophthalic acid, hexamethylenediamine and isophthalic acid Polyamide resin composed of bis (3-methyl-4-aminocyclohexyl) methane, isophthalic acid, ω-laurolactam, polyamide resin composed of hexamethylenediamine, isophoronediamine, isophthalic acid, terephthalic acid, or hexamethylenediamine , Bis (3-methyl- 4-
(Aminocyclohexyl) polyamide resin composed of methane, isophthalic acid and terephthalic acid.

These polyamide resins can be obtained by a so-called melt polymerization method by adding a lactam to a nylon salt comprising a diamine and a dicarboxylic acid or an aqueous solution thereof as required. Polymerization terminator represented by monoamine or monocarboxylic acid, heat stabilizer such as phosphate ester, surfactant, defoamer, antioxidant, antiblocking agent, lubricant when polymerizing as necessary , A pigment and the like.

The carbon black of the present invention has a pore volume of 2.5 cc / g or less according to a mercury porosimeter method, a maximum peak position of a pore distribution according to a mercury porosimeter method of 200 ° or more, and a DBP absorption. 20-250ml / 10
0g carbon black.

The mixing ratio of the amorphous polyamide resin having an aromatic ring in the molecule and the carbon black is appropriately 20 to 200 parts by weight, preferably 30 to 150 parts by weight of the carbon black per 100 parts by weight of the resin.

If necessary, additives such as a dispersant, a lubricant, and a softener may be added in an appropriate amount.

The conductive film of the present invention is obtained by uniformly mixing the carbon black and the resin, and then forming the film into a film having a thickness of 30 μm or less, preferably 20 μm or less, by a melt extrusion method or a solution casting method.

The melt extrusion method is not particularly limited as long as it is generally known, and specifically, a method of extruding from a T-type die to form a flat film (T-die method), and extruding from a ring-shaped circular die. At the same time, a method of blowing a compressed gas to form a tube-like film (inflation method), a stretching method of stretching the film obtained by these methods, and the like can be mentioned.

The solution casting method is not particularly limited as long as it is a known method, but for example, a carbon black is put into an organic solvent system in which a resin is dissolved, mixed well with a ball mill or the like, and the carbon black is dispersed. The coated paint is applied to a support such as a polyester film or a glass plate using a reverse roll, a gravure roll, a doctor blade, or the like, and the solvent is removed by evaporation after drying by evaporation to obtain a conductive film.

The conductive film of the present invention obtained as described above is used, for example, as a resistance layer for a current transfer recording material formed by laminating a conductive layer and an ink layer or a conductive layer, a release layer, an ink layer and the like. For example, in the case of producing a current-carrying transfer recording material composed of three layers, a resistance layer, a conductive layer, and an ink layer, after forming a resistance layer composed of a conductive film as described above,
As the conductive layer, a thin film of a good conductive material such as aluminum is formed on the resistance layer by an evaporation method or the like. The ink layer is applied on the conductive layer opposite to the resistance layer by a hot melt method or a solution method.

The ink layer is not particularly limited as long as it is used for a known thermal transfer recording material. For example, paraffin wax, modified wax, carnauba wax, etc., about 60% by weight of a wax, a coloring material pigment or Preferably, the dye comprises about 20% by weight and the resin about 20% by weight.

Each layer is formed as described above, and the thickness of each layer is 1 to 10 μm; 0.01 to 0.2 μm;
μm or less, preferably 2 to 5 μm; 0.05 to 0.1 μm; 20 μm
It is better to do the following.

Note that a release layer such as polyketone may be provided between the ink layer and the conductive layer in order to improve the separation between the ink layer and the conductive layer.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Example-1 1.140 kg of "NOVAMIT" X-21 (manufactured by Mitsubishi Kasei Kogyo Co., Ltd., amorphous polyamide resin having an aromatic ring in the molecule) pulverized to about 100 μm and carbon black # 10B (Mitsubishi Kasei Kogyo Co., Ltd.) 0.860 kg) was charged into a high-speed mixer having an internal volume of about 9, and mixed at 2,500 rpm for 1 minute at room temperature.

The obtained mixture was allowed to stand in a vacuum drier heated to 120 ° C., dried for 12 hours, and kneaded with a biaxial kneader (30φ, L / D = 25) to obtain a chip-shaped compound.

This compound was dried in a vacuum dryer at 120 ° C. for 24 hours, and then a conductive film was obtained using a single screw extruder (D = 30φ, L / D = 22) under the conditions shown in Table 1.

 Table 1 shows the physical properties of the obtained film.

Comparative Example-1 A conductive film was produced in the same manner except that the resin of Example-1 was changed to nylon-6 (manufactured by Mitsubishi Kasei Kogyo Co., Ltd.).

Comparative Example 2 The physical properties of a polycarbonate resin energizing transfer film (commercially available) were evaluated under the same conditions as in Example 1, and the results are shown in Table 1.

Examples 2-3 The types and amounts of carbon black of Example 1 are shown in Table.
A conductive film was manufactured and evaluated in the same manner as in Example 1 except that the film was changed as shown in FIG.

Application Example Aluminum was deposited on the film obtained in Example 1 to a thickness of 0.08 μm using a commercially available vacuum deposition apparatus.

Thereafter, an ink having the following composition was applied in a thickness of 4 μ on the deposition surface.

Ink composition and preparation method Carbon black ("MA-8" manufactured by Mitsubishi Kasei Co., Ltd.) 15 parts by weight Paraffin wax 25 parts by weight Oxidized wax 40 parts by weight Ethylene / vinyl acetate copolymer (manufactured by Hoechst) "TM-PEV-720") ... 20 parts by weight The above mixture was premixed with a mixer and then kneaded five times with a 6-inch three-roll mill. 3 μm in this ink
Above carbon black aggregates were absent.

Applied voltage 12V, pulse frequency 100H on finished ribbon
As a result of printing on plain paper under the conditions of z, pulse width of 2 ms, and paper feed speed of 16 mm / S, clear and smooth characters were recorded.

Evaluation method of various physical properties The DBP absorption of carbon black physical properties is JIS-K-62
Performed by the 21-A method.

Further, the pore volume and the maximum peak position of the pores were measured in a pore radius range of 75 to 75000 ° by a mercury intrusion method. (The equipment used is a micrometric instrument (Mi
Auto Pore by crometriics Instrument)
("Auto Pore") 9200) The resistance of the film was measured by the following method.

That is, a film piece having a diameter of 30 mm or more is connected to an electrode having a diameter of 25 mm (1.
1kg), apply a load of 1.0kg, and set the resistance after 30 seconds to “Digital Multimeter” TR-6856 (Takeda Riken)
Was measured.

The moldability of the film is 10cm for the film extruded with T-die.
² Thickness of a commercially available dial thickness meter (minimum 1 μm
The thickness was measured at 30 or more places, and the variation in the thickness with respect to the average thickness was evaluated as ○, 10% to 20% as Δ, 20% or more as ×.

Tensile strength and elongation were evaluated using "Tensilon" -UTM-5T (manufactured by Toyo Boardwin).

The sample used for the measurement was a film that had been left in an atmosphere with a humidity of 65% for 7 days, cut to a width of 15 mm and a length of 80 mm.
The measurement was performed under the conditions of a distance between chucks of 50 mm and a pulling speed of 500 mm / min.

(Example 4) The amount of carbon black was 35 wt%, and the amount of resin was
The experiment was performed under the same conditions as in Example 2 except that the content was 65 wt%.

As a result, the thickness of the film was 15 μm, the moldability was ○ (the variation in thickness was 10% or less), and the resistance was 82 ohms.

(Comparative Example 3) The blending amount of carbon black was 18 wt%, and the blending amount of resin was
The experiment was performed under the same conditions as in Example 2 except that the weight was 82 wt%, the take-up speed was 8.0 m / min, and the carbon black used was "Ketjen Black EC (manufactured by Japan EC Co.)". The reason for reducing the amount of carbon black is that if the amount is further increased, the moldability will be extremely deteriorated.

As a result, the film thickness was 22 μm, and the moldability was low despite the slow take-off speed (thickness variation 10-20%)
It became. Resistance was 95 ohms.

"Ketjen Black EC (manufactured by Japan EC Co.)" had a DBP absorption of 367 ml / 100 g, a pore volume of 3.09 ml / g, and no maximum peak of pores appeared. This is "Ketjen Black"
Is a high specific surface area product and activates the strength.
Since it is almost hollow, it looks like an egg shell, if pressure is applied to it with a mercury porosimeter, the carbon black will be crushed and measurement will not be possible. In the present invention, since such a material having a high specific surface area is not used, it can be measured with a mercury porosimeter.

〔The invention's effect〕

According to the present invention, the mechanical strength, which is a drawback of the polycarbonate resin resistance layer, is improved, and the strength and dimensional stability of the polyamide resin resistance layer, such as nylon-6, are deteriorated due to moisture absorption. Thus, an excellent resistance layer having improved resistance can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01B 5/16 (72) Inventor Hiroshi Urabe 1000 Kamoshidacho, Midori-ku, Yokohama-shi Mitsubishi Chemical Industry Co., Ltd. (56) References JP-A-59-120495 (JP, A) JP-A-60-71293 (JP, A) JP-A-58-42490 (JP, A)

Claims (3)

(57) [Claims] (1) a pore volume determined by a mercury porosimeter method;
5 cc / g or less, and the maximum peak position of the pore distribution according to the mercury porosimeter method is 200 ° or more, and the DBP absorption is 20 to 250 ml / 100 g. A conductive film comprising an amorphous polyamide resin having an aromatic ring in a molecule, obtained by a polycondensation reaction using at least one diamine having a ring and at least one dicarboxylic acid as starting materials. 2. The conductive film according to claim 1, wherein carbon black is blended in an amount of 20 to 200 parts by weight with respect to 100 parts by weight of the amorphous polyamide resin. 3. A starting material for an amorphous polyamide resin,
The conductive film according to claim 1 or 2, wherein a lactam is added.