JPS6297891A - Stencil film for electric recording - Google Patents

Abstract

PURPOSE:To enhance electrical properties, discharge perforation recording clearness and recording sensitivity, by a method wherein a compound prepared by mixing a thermoplastic resin with a specified amount of carbon black having an average particle diameter and a specific surface area in a specified ratio is formed into a film, which is stretched to a predetermined draw ratio. CONSTITUTION:A thermoplastic resin to be used has a film-forming capability, is resistant t the solvent used in a mimeographic ink, and has favorable dimensional stability. Carbon black having an average particle diameter of 15-60mmu and a specified surface area determined by a nitrogen adsorption method of 50-350m<2>/g is used in an amount of 25-40pts.wt. per 100pts.wt. of the thermoplastic resin. The compound thus prepared from the resin and carbon black is formed into a film 10-60mum in thickness, and the film is stretched monoaxially or biaxially by 75-300% of the original length at a temperature of 50-150 deg.C to produce a stencil film for electric recording.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an electrographic mimeograph film,
More specifically, it is an object of the present invention to provide an electrical recording copying film that is used in facsimiles or high-speed facsimile machines and has good electrical properties - discharge perforation recording clarity and recording sensitivity.

<Prior art and its problems> Conventionally, commercially available electric recording mimeograph films are
Normally the surface resistance value is around 1.0 x 10" 11,
The volume resistance value is about 5. Since the volume resistance value is higher, around Ox lo' IΩ, the discharge current during discharge recording is difficult to flow in the volume direction, and there is a drawback that the discharge perforation recording clarity and recording sensitivity are insufficient. Due to the high rotational speed (when used in I7), the above film also has the disadvantage that the diameter of the discharge perforations is small and the desired recording clarity cannot be obtained.

<Means for Solving the Problems> The present invention provides a novel electrical recording transcription film that solves the problems of the prior art, and its gist is that 100 parts by weight of thermoplastic resin is On the other hand, carbon black with an average particle diameter of 100 mμ or less and a specific surface area of 600 m"/P or less by nitrogen adsorption method is
-40 parts by weight of the blend is formed into a film and stretched by at least 5%.

<Configuration> The thermoplastic resin used in carrying out the present invention is not particularly limited as long as it has film-forming ability, has solvent resistance to the solvent of mimeograph ink, and has good dimensional stability. Examples of such materials include polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, polyolefin resins (eg, polyethylene, polypropylene, and ethylene copolymers).

Further, the carbon black used in the present invention has an average particle diameter of 100 mμ or less, preferably 15 to 60 mμ.
By voice, the specific surface area by nitrogen adsorption method is 600 doors/y or less,
Preferably, it is 50 to 350 doors/no. If the average particle diameter exceeds 100 mμ, the adsorption power to the thermoplastic resin will decrease, resulting in poor dispersibility, which is undesirable, and if the specific surface area exceeds 600 rrflt, the conductivity will be too strong, resulting in a decrease in volume resistance. It is not preferable because it has poor dispersibility.

This stiff carbon black is made of the thermoplastic resin 10
It is added in an amount of 25 to 40 parts by weight relative to 0 parts by weight. If the amount of carbon black is less than 25 parts by weight, the shape of the discharge holes will be rough and the printing will lack clarity, which is not preferable.
If it exceeds 0 parts by weight, the shape of the discharge perforation tends to become a continuous hole,
This is undesirable because it reduces printability.

In this way, the mixture consisting of a thermoplastic resin and carbon black may contain a plasticizer such as dioctyl phthalate, dibutyl phthalate, or polyester, a stabilizer such as Ba-Zn stearate, or Cd stearate, and titanium oxide. , pigments such as clay, additives such as oil, or metal powder may be added in appropriate amounts.

The compound prepared in this manner is formed into a film with a thickness of 10 to 60 pm by a film forming method such as a solution casting method, a calendar method, or an extrusion method, and is then formed into a film using a stretching method such as a tenter method or a roll press method. An electrographic copying film is prepared by stretching the film uniaxially or biaxially by at least 5%, preferably from 75 to 300%, under heating at 50 to 150°C.

If the film thickness before stretching is less than LOpm, mechanical strength is insufficient and pinholes may occur, which is undesirable. If it exceeds 60 pyt, the film thickness becomes uneven and it is necessary to increase the stretching ratio, which is undesirable. It is something.

In addition, if the stretching ratio is less than 5%, the volume resistivity value will not decrease much and the printed image clarity effect after discharge perforation will not be obtained, which is undesirable, and if it exceeds 300%, the pinhole will enlarge, which is undesirable. It is.

Note that the above-mentioned stretching operation may be performed simultaneously when forming a film from the blend.

The electrical recording copying film subjected to the stretching operation in this manner has a surface resistance value of 1.0 before stretching. OX 10”~1.0x
to”n, volume resistance value 1.OX 10” ~1. OX
10" Ω-1 to 6, but by stretching it under heating, the surface resistance value becomes 1.0 x 10" to 1.0".
OX 10'60, volume resistance value is 1. Ox 10”~1
．． OX 10"Ω. In other words, by applying the stretching process, the particle spacing of carbon black in the plane direction is widened and narrowed in the thickness direction, and the surface resistance value is as follows. The value becomes less after stretching than before stretching, and the amount of discharge current flowing in the volume direction during discharge recording increases.As a result, the diameter of the discharge holes also increases.

<Effects> Since the electrical recording copying film of the present invention is constructed as described above, it is characterized by having good electrical characteristics, discharge perforation recording clarity, and recording sensitivity.

<Examples> Examples of the present invention will be shown below. The text middle part means the weight part.

Example 1 Polyvinyl chloride (degree of polymerization 1000) 100
Part Dioctyl 7 Talate 30 Parts Polyester Plasticizer 10 Parts Carbon Black (Average Particle Size 30 mp s Specific Surface Area 213 r
rf/'i) 25 parts Ba-Zn stearate, 2 parts Cd stearate 1.5 parts After mixing the above formulation in a Henschel Schixer for about 30 minutes, 15 parts
A film was formed to a thickness of 30 mm using a baking roll maintained at 5 to 170°C. The surface resistance value of this film is 8. OX
to'' 0, and the volume resistance value was 3.0 x 10''Ω.

This film was stretched 150% with a roll kept at 80°C,
An electrographic mimeograph film having a thickness of 20 μm was obtained.

The surface resistance value of this film was 4.8 x 10'4 Ω, and the volume resistance value was 5.5 x 10110.

Next, in order to evaluate the characteristics of this film, a paint containing titanium oxide was applied to the surface of this film, and a mount containing carbon black (surface resistance value 102Ω) was applied to the other side, and the main component was polyvinyl alcohol. This was attached using an adhesive, and this was applied to an electric discharge plate making machine to make a plate at a scanning line density of 10 lines/piece.

The results were as shown in Table 1. Comparative Example 1 in Table 1 is a commercially available electrical record based on polyvinyl chloride resin, with a thickness of 20 pm, a surface resistance value of 5.0 x 10'4 Ω, and a volume resistance value of 4.5 x to'' Ω. It is a mimeograph film.

Note that the facsimile characteristics in Table 1 are at a rotation speed of 1300
Measured at r, p, m.

Example 2 Polyethylene resin (density 0.923) 70
Polyethylene resin (density 0.927)
30 parts carbon black (average particle size 27 mp specific surface area 80 nf/9) 35
1 part Mineral oil 10 parts The above blend was thoroughly mixed in a Banbury mixer, pelletized, and then put into an inflation extruder to form a film with a thickness of 25% m.

The surface resistance value of this film is 1.0 x 10140, and the volume resistance value is 5. It was OX 10'40.

This film was stretched by 125% on a roll maintained at 80°C to obtain an electrographic copying film with a thickness of 20 mm.

The surface resistance value of this film was 1.5 x 10"Ω, and the volume resistance value was 5.OX 10"Ω.

Next, in order to evaluate the characteristics of this film, it was coated with paint in the same manner as in Example 1, and was then bonded to a mount and measured.

The results were as shown in Table 2. In addition, Comparative Example 2 in Table 2 is based on polyethylene resin and has a thickness of 20 mm.
M, surface resistance value 1. Ox 10”Ω, volume resistance value 5.5
It is a commercially available electrographic mimeograph film of x 10''Ω.

Table 2 (Factors in Table 2) IJ characteristics are as follows: rotation speed 85
Measured at 0 r, p, m.

Comparative Example 3 Polyvinyl chloride (degree of polymerization 700) Loo part Dioctyl phthalate 40 parts Carbon black (average particle diameter 30 mμ, specific surface area 950
rrl/l) 20 parts Ba Zn stearate 1.5 parts Cd stearate The above mixture was formed into a film in the same manner as in Example 1 (surface resistance value 5.Ox 10'
o, volume resistance 4M t, o x lo' n ) sita.

However, this film had countless pinholes due to insufficient carbon black dispersion, and when it was stretched, the pinholes expanded into large holes, making it impossible to use it as a product. Ta.

Claims (1)

[Claims] 1) The average particle size is 100 mμ or less and the specific surface area is 60 mμ or less based on 100 parts by weight of the thermoplastic resin.
25 to 40 carbon black with a density of 0m_2/g or less
1. An electrographic copying film, which is formed by forming a mixture of parts by weight into a film and stretching the film by at least 5%. 2) The electrical recording copying film according to claim 1, wherein the thermoplastic resin is at least one selected from the group consisting of polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, and polyolefin resin. 3) An electrographic copying film according to claim 1, wherein the carbon black has an average particle diameter of 15 to 60 mμ.4) A specific surface area of carbon black determined by a nitrogen adsorption method is 5.
The electrographic copying film according to claim 1 or 3, which has a density of 0 to 350 m^2/g. 5) The electrographic copying film according to claim 1, which has a stretching ratio of 75 to 300%. 6) Surface resistance value is 1.0×10^1^3 to 1.0×10
^1^6Ω, volume resistance value is 1.0 x 10^1^3~1
．． The electrorecording copying film according to any one of claims 1 to 5, which has a resistance of 0x10^1^5 Ω.