JPS602198B2 - Electric recording mimeograph film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrorecording copying film, and more particularly to a novel electrorecording copying film having excellent discharge perforation recording properties and mechanical properties.

Conventionally, as electrical recording mimeograph paper, for example, 00 woven navy blue has been used.
Thin electrically conductive fine powder such as carbon black or fine metal powder is dispersed in thin paper or plastic film made of polyvinyl chloride, cellulose acetate, polyethylene, etc. to reduce volume resistance and give discharge perforation. is used. In order to enable electric discharge perforation, electrical recording paper must generally have a volume resistivity of about 1 x 1 to 1 x 1 pi, and in order to obtain such a volume resistivity, thin paper or A large amount of conductive inorganic fine powder is dispersed in the plastic film substrate in an amount of 15 to 35% by weight based on the weight of the film. However, when mixing such a large amount of inorganic fine powder,
This has disadvantages in that the mechanical strength of the tissue paper or plastic film decreases, making it difficult to manufacture and reducing printing durability. Furthermore, it is difficult to uniformly disperse the conductive inorganic fine powder, so there are many drawbacks such as the inability to obtain uniform discharge perforation and the inability to produce sharp mimeograph printing. Tissue paper or plastic films containing such a large amount of military-conducting inorganic fine powder have a lower volume resistivity and lower surface resistance, which makes it easier for surface current to flow during discharge perforation recording operations, resulting in random discharge perforations. Therefore, it is not possible to obtain a high-resolution record mimeograph. For this reason, in order to suppress the flow of surface current in the electrical recording paper that is currently available on the market, a surface layer (for example, a titanium oxide dispersed layer) with a resistance greater than that of the base paper itself is placed on the surface. is applied. In addition, in Mochiko Sho 39-13718, carbon black etc. are mixed into the resin to increase the surface resistance from IQ to IQ.
It has been proposed to increase the surface resistance by making a Q film and wiping its surface with a solvent that swells and dissolves the resin appropriately. However, such mimeograph paper requires a special process to reduce surface resistance and is expensive, and because a surface coating layer is provided or only the surface layer is swollen with a solvent, the physical properties of the front and back surfaces are different and curl. Due to the difference in distortion between the front and back surfaces, there is a difference in shrinkage due to heat during drilling, resulting in distorted holes and even worse curling.
In extreme cases, it becomes unusable, and this tendency is particularly pronounced in extruded and calendered films because they are oriented in the winding direction.Therefore, it is desirable to avoid such surface resistance reduction treatment as much as possible.

According to the present invention, when carbon black, which has a very large surface area of at least 800 m/m by the recently developed nitrogen adsorption method, is used as a conductive material for electrorecording and copying films, the amount used can be reduced to approximately 100%. Quite surprisingly, films formed with such high surface area carbon black dispersed exhibit high surface resistivities despite having the desired low volume resistivities; It was discovered that such a surface resistance reduction treatment was not necessary, and the product was developed. Thus, according to the present invention, a film-forming resin composition containing 6 to 22 parts by weight of carbon black having a surface area of at least 800 mm by nitrogen adsorption method per 100 parts by weight of a thermoplastic resin is formed into a film. A molded electrographic mimeograph film is provided. The carbon black used in the present invention is carbon black or acetylene black, which is conventionally used for electrical recording mimeograph paper.
Surface area of 00 w/ta or less [Nitrogen adsorption method (ASTM-D3
037-71T) Unless otherwise specified hereinafter, "surface area"
refers to the surface area determined by nitrogen adsorption method], but it is characterized by a very large surface area of at least 800 m/h.

There is no particular limit to the upper limit of the surface area, but generally 1200
〆/ta or less is sufficient, especially 900 to 1100
The end/evening range is suitable. Carbon black with such a large surface area is extremely porous, has excellent conductivity (3 to 4 times that of commercially available conductive carbon black), and has a relatively small particle size (approximately 20 to 30 mm). ) and has various excellent advantages such as strong adhesion to plastics.

Therefore, even if carbon black having such a large surface area is mixed in a small amount into a resin substrate, its volume resistivity can be greatly reduced, and moreover, carbon black can be uniformly and finely dispersed.

Thus, carbon black that can be particularly preferably used in the present invention has the following basic characteristics.

Surface area (Nitrogen adsorption method 900-1100 / Polyiodide adsorption method 800-1100 9 / Oil absorption (DBP adsorption) 300-400 / 100
Volatile content 2% or more PH
6-11 ash content 1% or less particle size
15 to 200 my In the present invention, carbon black is used in an amount of 6 to 100 parts by weight of resin.
Using a relatively small amount of ~22 parts by weight, preferably 8-15 parts by weight, the 1×1 to 1×1 required for electrographic mimeograph paper is
The resin composition can have a volume resistivity of Q and Q.

Further, there are no particular restrictions on the type of thermoplastic resin that can be used as a substrate in the electrographic mimeograph film of the present invention as long as it has film-forming properties; It is preferable that the material has a high strength and a certain degree of dimensional stability. Examples of such resins include vinyl resins, polyolefin resins, polyester resins, polyamide resins, acrylic resins, thermoplastic resins such as polj carbonate; or natural or recycled resins such as cellulose acetate and nitrocellulose. Examples include resins, especially polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyethylene, polypropylene,
Cellulose acetate, ethylene-vinyl acetate copolymer, nitrocellulose or mixtures thereof are preferred.
Additives commonly used in film forming, such as plasticizers (e.g. DOP, DB) may be added to such resins as necessary.
P. DOA, DIDA, TPP, etc.), lubricants (e.g. calcium stearate, zinc laurate, barium ricinoleate, etc.), heat stabilizers (e.g. organotin compounds, Ba, Ca
, organic acid salts of metals such as Zn), pigments (e.g. titanium oxide,
Calcium carbonate, talc, clay, etc.), antioxidants (eg, ditertiary butyl hydroxytoluene, etc.), and others can be included in the usual amounts. In addition, in Mochiko Sho 41-33 Female Publication, in order to reduce the amount of carbon black mixed in, alkyltrimethylammonium salt,
It is proposed to use a conductive surfactant such as a surfactant polyquaternary ammonium salt, but if such a conductive surfactant is used in combination, the film surface will become sticky and difficult to handle, and the moisture resistance will deteriorate. However, in the film of the present invention, as mentioned above, the film of the present invention has certain disadvantages, such as being easily affected by moisture, making electrical resistance uneven, and making uniform discharge perforation difficult. Since the amount of carbon black incorporated can be reduced, the use of such a conductive surfactant is not particularly required.

The electrographic copying film of the present invention can be produced by a conventional film forming method, such as a solution casting method or a hot melting method (extrusion method, calender method, etc.). For example, when manufacturing by the solution casting method, plasticizers, stabilizers, etc. are added to the resin and carbon black, and the mixture is kneaded for 5 to 18 minutes in a rice bran mixer such as a Banbury mixer, followed by a two-roll or extruder machine. etc. to make a pellet.

A solution of this pellet dissolved in a solvent such as acetone-benzene, methyl ethyl ketone-toluene, or tetrahydrofuran was poured down through a narrow slit depending on the required film thickness to form a film on a stainless steel belt, and then dried. A film of 10-50r is obtained. After cooling, this film is peeled off from the belt and wound up. At this time, paper or plastic film may be used as the support instead of the stainless steel belt. In addition, in the case of manufacturing by the calender method, pellets are manufactured in the same manner as the above-mentioned casting method, and the pellets are fed to a calender roll.
The film is made into a film with a thickness of about 50 mm on a calender roll at 0° C. to 1-8 mm, and then stretched vertically and/or horizontally depending on the required thickness to obtain a film with 10 to 50 mm.

The obtained film is heat-set with a hot roll or hot air at 150 to 200° C. to improve dimensional stability, if necessary, and then cooled and wound up. The electrical recording copying film of the present invention generally has a volume resistivity of 1×1 to 1, although it varies depending on the type and amount of carbon black, the type of resin, etc.
×1pioQ, especially in the range of 1×1pi to 1×1biQ,
On the other hand, the surface resistance is 1 x 1 to 1 x 60, especially 1
It is in the range of ×1 and 1 to 1 and 40.

Also, the thickness of the film of the present invention is not critical, but can generally be from 10 to 50 µm, preferably from 13 to 30 µm. As mentioned above, the mimeograph film provided by the present invention has excellent mechanical strength because it contains a small amount of carbon black, and although it differs depending on the type of resin substrate,
For example, the tensile strength is at least 1.5k9/〆, the elongation at break is at least 60%, there is no tearing during mimeograph printing, and the number of printed sheets can be dramatically improved.

In addition, since the film of the present invention has finely dispersed carbon black particles, it is possible to perform discharge perforation uniformly and finely, thereby significantly improving the resolution and sharpness of mimeographed prints. I can do it.

Thus, the electrorecording copying film of the present invention can be used as an electrorecording copying paper as it is or in combination with a conductive mount.

Next, the present invention will be further explained by examples. Note that the test method described in the examples was measured by the following method. Tensile strength: According to JISK-6732.

Elongation rate: According to JISK-6732. Volume electrical resistance: According to JISK-6723. Surface electrical resistance: According to JISK-6723. Measuring method of resolution: Average (mountain) of drilled holes The diameter and dispersion of the holes drilled by electrical discharge are measured using a microscope.

Confucius's average is less than 30 threads → ink does not pass through → defective 0 50-100 Buddha → ink passes better → especially good 50-150 mu → ink passes better but there is a possibility of tearing → good 150 threads or more → Becomes easily torn → Defective {Low printing quality It is determined how much of a line on a document drawn with lines of various sizes from 250 mm to LOOOOA can be resolved in a printed matter.

For example, 10 lines at 1c intervals → lines the thickness of 1 rib, 20 lines at 1 ga interval → lines 500 Buddhas thick, 25 lines at 1 skin interval → 400 Buddhas thick. line, other 28, 30, 32, 3
There will be 5 thin lines.

Example 1 Polyvinyl chloride (P=1200) 5
Base weight part Vinyl chloride/vinyl acetate copolymer 44 parts by weight (vinyl chloride/vinyl acetate = 90/10) DOP
25 parts by weight of carbon black 1 part by weight (surface area of 1000/unit)*Barium stearate 3 parts by weight*Other characteristic values of this carbon black are as follows.

Iodine adsorption amount 950 side/Ta oil absorption amount (D
BP adsorption) 340'/100 ta volatile content
1% pH
9.5 ash content
0.5% particle size
The above components were mixed and kneaded in a Banbury mixer at 130° C. for one interval, and then dissolved in a mixed solvent of acetone/benzene in a ratio of 3:7.

This solution is uniformly cast onto a polyester film,
A film with a skin thickness of 0.02 was created. The properties of this film were as follows. tensile strength:
2.8k9/rib 2 elongation rate:
100% volume electrical resistance: 2×
1piQ surface electrical resistance: 2×1bi40
In order to measure the printability of this film, a plate was made using a torsion ax (electronic recording device, manufactured by Tokyo Aircraft Instruments). There were no continuous linear holes that could cause tearing, and each perforation was independent. The holes were uniform with an average diameter of 80A.

When this mimeograph paper was mimeographed on a rotary press, the resolution of the printed matter was sufficient to produce scale images up to the lines drawn at the rate of 1/2 dollar book. Also, in the printing durability test, 3
Even after printing 10,000 copies, the base paper did not tear, and the resolution of the printed matter did not deteriorate and remained clear. Example 2
'Polyvinyl chloride (P=800) 10
parts by weight DOA 3 parts by weight Carbon black (1100〆/night) 15 parts by weight Calcium stearate 3 parts by weight The above ingredients were mixed and kneaded for 1 minute in a Banbury mixer, then mixed with methyl ethyl ketone notolene (8/2 ) in a mixed solvent at a concentration of 30% by weight at approximately 70 qo.

After cooling to room temperature, the solution was thinly cast onto a stainless steel belt and dried to produce a uniform film with a side thickness of 0.03. The properties of this film were as follows.

Tensile strength: 2.1k9/2 ribs Elongation rate: 160% Volume electrical resistance: 3 x 1070 Surface electrical resistance: 1 x 120 Using this film, the average diameter of the holes when perforated in the same manner as in Example 1 is 85 degrees uniformity, it is possible to resolve lines drawn at a rate of 30 lines per skin interval on the original, and there is no tearing or decrease in resolution even after printing 30,000 sheets using this film. It was clear and hot.

Comparative Example 1 Polyvinyl chloride Spot weight part Vinyl chloride-vinyl acetate copolymer 42 parts by weight (vinyl chloride/vinyl acetate copolymer)
Vinyl acetate = 90/10)DOP
25 parts by weight carbon black
4 parts by weight (1.5 parts by weight of zinc stearate with a surface area of 500 mm) and 1.5 parts by weight of barium stearate.
After kneading for 2 minutes with a banbali mixer, it is about 17,000 yen.
A film having a thickness of 0.02 mm was prepared using a calendar roll.

The properties of the obtained film were as follows. tensile strength:
2.1kg/job 2 growth rate:
60% volume electrical resistance: 8
× 1 pi○ Surface electrical resistance: 2 × 1 pi○ Using this film, a plate was made in the same manner as in Example 1, and a printing test was conducted. As a result, the size of the perforations was uneven.
The resolution was low and it was easy to tear.

Examples 3 to 5 and Comparative Example 2 The amount of carbon black added to the resin of the film produced in the same manner as in Example 2, the physical properties of the obtained film, and the measurement results of its print quality are as shown in the table below.

Claims (1)

[Claims] 1. A film-forming resin composition containing 6 to 22 parts by weight of carbon black having a surface area of at least 800 m^2/g by nitrogen adsorption method per 100 parts by weight of a thermoplastic resin. A molded electrical recording mimeograph film. 2 The carbon black is 900 to 1100 m^2/g
The film according to claim 1, having a surface area determined by a nitrogen adsorption method. 3. The film according to claim 1, having a volume resistivity of 1 x 10^4 to 1 x 10^1^0 Ω and a surface resistance of 1 x 10^9 to 1 x 10^1^6 Ω. 4. The film according to claim 1, which contains 6 to 22 parts by weight of carbon black per 100 parts by weight of the thermoplastic resin. 5 The thermoplastic resin is polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyethylene, polypropylene, cellulose acetate, ethylene-vinyl acetate copolymer,
The film according to claim 1, which is nitrocellulose or a mixture thereof.