JPH01237196A - Heat-sensitive stencil film and stencil paper - Google Patents

Abstract

PURPOSE:To prevent a stencil sheet or stencil paper from being fused to a thermal head and enhance resolution of a printed matter, by providing a film with an anti-sticking layer comprising an alkyl-modified silicone oil as a main constituent at a surface thereof to be brought into contact with the thermal head. CONSTITUTION:A heat-sensitive stencil film to be made into a stencil by a thermal head is provided with an anti-sticking layer comprising an alkyl- modified silicone oil as a main constituent at a surface thereof to be brought into contact with the thermal head. A heat-sensitive stencil paper comprises a film laminated with a porous base, and an anti-sticking layer comprising an alkyl-modified silicone oil as a main constituent is provided on the non- adhered side of the film. The film may be a polyester, nylon, polyolefin, polystyrene, acrylic acid derivative or polycarbonate copolymer or the like. The anti- sticking layer comprises the silicone oil in an amount of at least 50wt.%. If the amount is less than 50wt.%, a uniform film of the silicone oil can not be provided, and the intrinsic anti-sticking effect thereof is hardly displayed. The amount of the anti-sticking layer may be 0.01-0.8g/m<2>.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a heat-sensitive stencil film and a base paper suitable for producing a stencil blank using a thermal head, and more particularly relates to a heat-sensitive stencil film and a base paper that are uniaxially or biaxially stretched. plastic film,
A heat-sensitive stencil film and a film for heat-sensitive stencils, which preferably have an anti-stick layer made of a specific silicone oil on the surface of the copolymerized polyester film to prevent heat fusion with a thermal head during plate making and improve the resolution of printed matter. Regarding the original paper.

(Prior art) Methods for creating a thermal stencil master include digital plate making using a thermal head (hereinafter referred to as TH method) and method of irradiating infrared rays or xenon flash light (hereinafter referred to as flash method).
is already publicly known.

In particular, compared to electrostatic copying (PPC), the TH method is rapidly becoming popular in offices, schools, etc. because the printing cost is low when printing a large number of sheets, and high-speed printing is possible. However, in the TH method, when punching, the head and the film of the thermal stencil paper (hereinafter referred to as the film) are thermally fused (stick) and the punched area becomes enlarged and deformed (this causes the characters on the printed matter to thicken or blur). In the TH method, problems such as tearing and peeling of the film occur.
During plate making, the surface temperature of the head usually increases to 30°C within a few milliseconds.
The temperature reaches about 0 to 500°C, and as a result, the head and film instantaneously cause a stick phenomenon in most cases. In this case, even if thermal adhesion occurs in even a small portion of the heat generating element of the head, unlike the flash method, the head (heat generating part) and the film are constantly moving relative to each other.
A serious problem like the one mentioned above will occur.

Furthermore, recently, films with improved perforation sensitivity (hereinafter referred to as high-sensitivity films) have been proposed for the purpose of high-speed plate-making, low-energy plate-making, and high resolution (JP-A No. 6).
2-282983, etc.).

A digital plate making machine using a commercially available thermal head uses a commercially available crystallized polyester film (melting point: 24 μm).
The perforation energy has been specially increased for heat-sensitive stencil paper (hereinafter referred to as stencil paper), which is made by laminating 5 to 260'C) and a porous support such as Tengucho paper. When paper made with high-sensitivity film is run through a plate-making machine, stickiness becomes noticeable. In addition, special uses for high-speed films are being considered, which are different from those for ordinary films. For high-sensitivity films, it is possible to use only a thick (5 μm or more) film alone as a printing original plate (base paper without a support) without pasting it with a porous support (temporarily adhere the mount and use a word processor etc. After making a plate, it can be peeled off and used as an original plate.) In this case, if the sticking problem is solved, there will be no feeling of sticking in the flat portion due to the support, and high-quality printing can be performed more advantageously than with conventional base paper. but,
Normally, the thicker the film, the stronger the heat fusion with the thermal head tends to be (Japanese Patent Laid-Open No. 60-48398).

Currently, numerous patent applications have been filed for stick prevention methods. They are coated with fatty acid metal salts (
% Sidelight No. 60-19592), with an overcoat layer of phosphate ester type surfactant (Japanese Patent Laid-open No. 61
-125897), those provided with a silicone release layer (solid) (such as JP-A-60-97891), and those provided with a means for applying a fluid lubricant such as silicone oil in the plate-making machine ( Japanese Patent Application Laid-Open No. 60-154068,
JP-A No. 63-30295), etc. but,
It has not been possible to perform accurate perforation that allows for high-quality printing without reducing perforation sensitivity. Furthermore, the current situation is that the heat generating part of the thermal head becomes dirty, and the stick prevention effect is unstable over time, so that fully satisfactory results have not been obtained. Furthermore, no method has been found that is particularly effective in preventing sticking in the high energy range for high-speed films.

(Problems to be solved by the invention) The problem of thermal fusion when creating a thermal stencil plate is solved by the TH method,
Occurs with the flash method. However, in the case of the flash method, there is no relative movement between the film and the document to be thermally fused, so even if there is a fusion point, it will not be a problem as it will peel off after cooling. Wear is a serious issue. In addition, it is said that the energy added for perforation is generally smaller in the TH method than in the flash method, and when a layer is provided on the film surface to prevent sticking, etc. The characteristics and the amount of adhesion greatly influence the perforation sensitivity of the film.

Therefore, it is of great practical importance to provide a stick prevention layer that can stably prevent the adhesion of residue to sticks and heads without reducing the perforation sensitivity of the film in a small amount.

Here, silicone oil exhibits high mold release properties and is stable against temperature. However, there are not many examples of its use as an agent to prevent sticking with a thermal head during plate making. Silicone oil is generally liquid at room temperature, so some types of silicone oil may come into contact with it while it is applied to base paper and stored in layers (especially when rolled)
The silicone oil transfers to a porous support such as tengucho paper (Japanese Patent Application Laid-Open No. 61-295098), and the stick prevention effect is reduced. For this reason, a method has been proposed in which a coating means is provided in the plate making machine (Japanese Patent Laid-Open No. 63-30295
Publication No.).

In addition, although examples have been shown in which certain silicone oils are used as anti-stick agents, sufficiently favorable results have not been obtained. For example, when water-soluble silicone oil is used in a polyester film, the stick prevention effect is not sufficient (Japanese Patent Laid-Open No. 60-1312
When silicone oil is used (such as the comparative example in the specification of Japanese Patent Application Laid-open No. 62-238792), the resulting printed matter has drawbacks such as a lot of ink smearing (Japanese Patent Laid-Open Publication No. 62-238792).

(Means and effects for solving the problem) As a result of intensive research aimed at solving the above-mentioned problem, the present inventors have discovered that a particular silicone oil among silicone oils exhibits a remarkable stick prevention effect. This heading led to the present invention.

That is, the present invention is characterized in that, in a heat-sensitive stencil film that is made by a thermal head, a stick prevention layer mainly composed of alkyl-modified silicone oil is provided on the surface of the film that comes into contact with the thermal head. A heat-sensitive stencil film, and a heat-sensitive stencil base paper, characterized in that the film is laminated with a porous support, and a stick prevention layer mainly composed of alkyl-modified silicone oil is provided on the non-adhesive surface of the film. be.

The film used in the present invention includes polyester (
Preferred examples include copolymer (polyester), nylon (preferably copolymer nylon), polyolefin, polystyrene, acrylic acid derivative, ethylene/vinyl alcohol, and polycarbonate copolymers.

Preferably, the film has a high perforation sensitivity, which is more effective, and for this purpose, the thermoplastic resin in the state constituting the film has a crystalline change ranging from a substantially amorphous level to 15%. Things are good. More preferably, the film is substantially amorphous.

Here, a film with a substantially amorphous level is one in which the melting point of the raw material is hardly observed even by the DSC method (however, the mixture was measured at a heating rate of 10°C/min). There are also cases where crystallization is suppressed by processing methods (quenching method, etc.). The former is preferred.

Further, the crystallinity may be simply determined by measuring a sample in which the crystallinity has been clarified using a DSC method, and calculating the area ratio of the dissolution energy measured in the sample to be measured. Preferably, the DS is calibrated in advance using a density method, an X-ray method, etc.
It is best to measure using the C method without supporting the crystalline state (e.g. under elevated temperature conditions).

More preferably, the film is mainly composed of copolymerized polyester, and is substantially amorphous. Most preferably, the copolyester as a raw material is substantially amorphous. Here, substantially amorphous polyester is different from resins mainly made of so-called highly crystalline polyethylene terephthalate whose crystalline melting point (according to DSC method) is 245 to 260°C, which is usually commercially available. The raw material is a polymer consisting of a single polymer and a mixed component, or a composition of a blend of polymers, which is sufficiently annealed to reach an equilibrium state, and the crystallinity is fixed by X-ray method. The degree of crystallinity measured by the density method using the sample as a standard (density measurement is based on JIS K-7112) is 10% or less, preferably 5%.
Hereinafter, it is more preferable that the melting point is hardly observed even by the DSC method. Substantially amorphous polyester is
To explain in detail the monomers constituting the polymer, the acid components include terephthalic acid, its isomers, derivatives thereof,
1 selected from aliphatic dicarboxylic acids, derivatives thereof, etc.
Utilizing a seed or two or more acid components, then glycol (
Alcohol) components include ethylene glycol, its derivatives (polyethylene glycol, etc.), alkylene glycols (trimethylene glycol, tetramethylene glycol, hexamethylene glycol, etc.), fatty acid saturated cyclic glycols (cyclohexanediol, cyclohexane dimetatool, cyclohexane). Dialkylols, etc.] Polymerization is carried out using one or more than 2 ffi glycol components selected from diols having an aromatic ring, for example, a bisphenol nucleus.Preferably, at least an alcohol component of both components is co-polymerized. It is a polymerized product, and its ratio is the same as the level of the copolymerized polyester described above.The next detailed preferred combination is to select terephthalic acid as the main acid component, and optionally include isomers (isophthalic acid, phthalic acid). It may contain a small amount (15 mol % or less) of ethylene glycol and cyclohexane dimetatool as the alcohol component.More preferably, the acid component may contain the same as above. An alcohol containing mainly terephthalate was selected, and an alcohol containing ethylene glycol and 1,4-cyclohexane dimetatool was selected as the main alcohol component. , 60 to 80 mol% of ethylene glycol, 40 to 20 mol% of 1,4-cyclohexane dimetatool, more preferably 64 to 75 mol% of the former, 36 to 25 mol% of the latter, most preferably the former. is 67 to 73 mol%, and the latter is 33 to 27 mol%.

The thickness of the film used in the present invention is preferably 0.5 to 7 μm, more preferably 0.7 to 5 μm, when used in combination with a porous support such as Tengucho paper or Tetron gauze.

In addition, when using dot-shaped perforations that do not require a porous support for reasons of economy, simplicity, and high resolution, it is necessary to etc., 5 to 15 μm 1 preferably 6 to 13 μm 1
More preferably, it is 8 to 12 μm.

The porous support used in the present invention is made of natural fibers, recycled fibers, synthetic fibers, etc., which are permeable to printing ink and do not deform even under heating conditions that perforate the film. Examples include mixed tissue paper, nonwoven fabric, woven fabric, and the like. For non-woven tissue paper, 30 to 3
g/m”, preferably 20-4 ji 7
m", more preferably 15 to 4 fi/m". In addition, in the case of woven fabric type mesh, 500 to 1
The number of meshes is 5 meshes, preferably 300 to 50 meshes, more preferably 250 to 80 meshes, and an appropriate one may be selected depending on the degree of resolution required for printing. Particularly preferred is a nonwoven fabric type porous support made of 0.5 to 5 denier polyester fibers, regenerated cellulose fibers, or a mixture of both.

When the above-mentioned heat-sensitive stencil film and base paper are plate-made using a high-energy thermal head of a commercially available printing machine, word processor, facsimile, etc., stick phenomenon occurs in most cases unless a stick prevention treatment is applied to the film surface. do. The present inventors conducted research on the production of printing plates (perforation of film) by the TH method and found the following important points.

First, the first K, as mentioned above, thermal fusion in the flash method and T.
Heat fusion in the H method cannot be handled in the same way.

In the TH method, the thermal element of the thermal head and the film move relative to each other under heating, so even the slightest melting point of the solder becomes a problem. Particularly in the present invention, a highly sensitive film is preferably used. Since the high-sensitivity film uses an amorphous or low-crystalline material, it tends to become sticky during perforation and melting, and since the melted polymer tends to aggregate and form a lump, the occurrence of stick is significant. For this reason, in order to prevent even the slightest fusion points, the anti-stick layer must be uniform and especially unusually effective. If the core layer is a solid layer, it will inhibit heat transfer during drilling and make the heat transfer non-uniform. Also, it is difficult to form a thin uniform layer. Secondly, since the head and film are moving relative to each other, even if a uniform layer can be formed, depending on the type of film, it may be rubbed off by the head. Therefore, even if a large amount is formed to the extent that drilling is inhibited, stick may occur in some cases. Thirdly, as mentioned above, the present invention also deals with base paper that does not require a support, and because it does not require a porous support, it is particularly sensitive to sticks.

It has also been found that the thicker the film, the stronger the anti-stick treatment must be. Further, as mentioned above, for example, 0.5 to 5 denier polyester f
a. A porous support mainly composed of fibers is preferably used in the present invention. In this case, as with the support-free base paper, clear printed matter can be obtained as long as no stickiness occurs. However, the support is not stiff, and when stickiness occurs, the base paper becomes loose (therefore, the image is distorted), and troubles such as the base paper jams in the plate-making machine occur. Needless to say, special care must be taken when using a high-speed film.

Based on the above findings, we have achieved the stick prevention solution of the present invention (that is, in the present invention, the stick can be prevented without reducing the perforation sensitivity of the film even by using thermal heads made of various materials in the high energy range to the low energy range). This is the first paper that can be used to accurately perforate film and perform high-speed plate making using high energy.The film surface that comes into contact with the thermal head is coated with a stick-preventing material based on a specific alkyl-modified silicone oil. It is about providing layers.

The alkyl-modified silicone oil used in the present invention is
The outline thereof is shown in the following formula (I), but it is not limited thereto. Preferred examples include α-olefin modified type and α-methylstyrene modified type.

Alkyl-modified silicone oil has several characteristics. First, it has an affinity for organic compounds, and there is no ink repellency (it has painterly properties).

Therefore, the silicone oil does not prevent ink from passing through the support during storage of the base paper. 2nd K.

Since the silicone oil has an alkyl group, it has better boundary lubricity than other silicone oils. Therefore, it is thought that the thermal stability of silicone oil and the boundary lubricity achieved by alkyl modification can prevent thermal fusion between the thermal head and the film, which move relative to each other at high temperatures.

Furthermore, α-methylstyrene-modified silicone oil is particularly effective for polyester films.

The reason for this is not clear in detail, but it is thought to be due to the characteristics of the silicone oil and polymer (functional groups, molecular structures such as having a benzene nucleus, etc.).

In addition, the viscosity of the silicone oil is not particularly limited, but
Considering volatility and thermal stability, a certain molecular weight is required (therefore, rn h n + in the above formula (Il)
X is also limited). Therefore, the viscosity is also limited by mechanical slippage in the plate-making machine (poor slippage can cause problems such as distorted images and paper jams due to the base paper not being fed).
Considering this, the value measured according to JISK-2283 is preferably 100 to 1.000 at 25°C.
0OOCS (centistokes), more preferably 200 to 50,000 CS, more preferably SOO to
20.000 CS, most preferably 1.000-1
It's ooocs.

The anti-stick layer in the present invention is mainly composed of alkyl-modified silicone oil, and the silicone oil is present in the layer in an amount of 50% by weight or more, preferably 70 to 100% by weight.
]! The amount is %. If the amount is less than 50%, a uniform film of the silicone oil cannot be formed and the unique stick prevention effect tends to be difficult to exhibit. Further, other components to be mixed into the stick prevention layer are selected from those that do not inhibit the stick prevention effect of the silicone oil, and more preferably those that inhibit transfer, absorption into the inside of the film, etc., and also prevent stick prevention. It is fine as long as it increases the effect. These include, for example, solid fine particles (5 μm or less) of inorganic substances such as silica, talc, carbon, graphite, molybdenum compounds, mica, etc., and fine particles (5 μm or less) of fatty acids, fatty acid esters, fatty acid amides, resins, etc.
(below) etc. Further, an antistatic agent, a substance that improves heat conductivity, etc. may be added.

Furthermore, the anti-stick layer has an area of 0 per unit area Cd).
．． Approximately 01 to o, s, and p are sufficient. It varies depending on the substance constituting the anti-stick layer, but preferably o, o 1
S-o,s g/m! , more preferably 0.01 to 0.
31/m2.

Furthermore, methods for forming the anti-stick layer include coating, spraying, kneading into a polymer constituting the anti-stick layer, and transferring from another layer by coextrusion.

(Examples) Hereinafter, the present invention will be further explained with reference to Examples, but the present invention is not limited thereto.

Examples and Comparative Examples Substantially amorphous copolyester (Eastman
Manufactured by Kodak, product name: KODAR PETG6763
) is extruded with a T-die to form a sheet, and the sheet is stretched with a stretcher at 90°C biaxially by 3.5
Films of 2 μm and 8 μm were obtained by stretching 3.5 times. Among these, a thermosensitive stencil paper was prepared by laminating thin paper (manufactured by a wet method) mainly made of polyester ##i with a basis weight of 11 fi/m'' to a 2 μm film using a methanol solution of vinyl acetate adhesive. (Base paper A).

In addition, the concentration of the solution was adjusted to y1 so that the adhesive adhesion amount was 397 m'' after drying. Also, for the 8 μm film, 150 mesh Tetron gauze was coated without using adhesive (layered). It was also used as a mount during perforation, and was later peeled off to leave only the film as an original (base paper B).

These base papers were coated with the solutions shown in Table 1 using a wire paper to produce films and base papers for heat-sensitive stencils, and the films and base papers for heat-sensitive stencils were evaluated. Table the results.
Shown in 2. The evaluation method is as shown below.

(1) Evaluation of stick prevention effect and printed matter Each base paper treated as described above was tested with a personal word processor, Word Boy FW-70 (manufactured by Canon, 32X
32-dot printing matrix, printing speed 8.5
character/second) and its print density level is “Dark”.
(maximum printing energy) (maximum thermal head surface temperature was about 500° C.), and then printing with a stencil printer Lingraph AP7200 (manufactured by Riso Kagaku Kogyo Co., Ltd.).

The printing pattern consists of 126 special symbols (i o, s point JIS size printing) including numbers, hiragana, kanji, and solid parts, and out of the total number of symbols, sticks occur, holes widen, or the film When printed, the black part of the ink is larger than the size of the symbol (count the number of symbols in the spread state, and the percentage of the symbol is less than 2% as O and pass the line, and 2 to 5% as △ (below is unacceptable). Passed), 5~
80% was indicated as ×, and 80% or more was indicated as XX. Also,
If the print is clear, ○ (the clearest one is ◎), if the hole is slightly enlarged and the print is blurred and the clarity is reduced, Δ
If there were too many sticks and the printed matter was unclear, or if the film was not sufficiently perforated and the printed matter was difficult to read, it was rated as ×.

(2) Non-transferability 10 sheets of heat-sensitive stencil paper with a thin layer formed as described above were placed on top of each other and a weight of 7 m'' was placed on top of them and left at 35°C for one week. After that, the stick prevention effect was determined by the method described above. ○ is the case where there is no change in the stick prevention effect before and after leaving it, and Δ is the case where there is a slight decrease in the effect.
, and those with a significant decrease were marked as ×. However, measurements were not made for those in which 5% or more stickiness occurred even before being left standing. (Indicated by - in Table 2).

In all of the Examples, clear printed matter was obtained, and the non-transferable buttons were excellent. In particular, the clearest printed matter was obtained with the base paper that did not require a support (base paper B) (Example 5).

When alkyl-modified silicone oil is used, it is effective even in a small amount, and the effect is significantly greater than that of other silicone oils (for example, dimethyl silicone oil, ether-modified type, etc.).

Table 1 Table 2 (Effects of the Invention) According to the present invention, the stick resistance of the thermal head and film is greatly improved, and high resolution thermal stencil printing becomes possible. It can be used under a wide range of plate-making conditions (from high energy and high temperature ranges to low energy and low temperature ranges, and high-speed plate making with high energy), and can be used for applications such as perforation without the need for a support, thereby expanding its uses. It also results in higher quality printed matter than electrostatic copying (PPC).

Patented wheat flour Asahi Kasei Industries, Ltd. Procedural amendment (voluntary) May 70, 1986

Claims (2)

[Claims] (1) A heat-sensitive stencil film made by a thermal head, characterized in that a stick prevention layer mainly composed of alkyl-modified silicone oil is provided on the surface of the film in contact with the thermal head. film (2) A heat-sensitive stencil paper, characterized in that a film and a porous support are laminated together, and a stick prevention layer mainly composed of alkyl-modified silicone oil is provided on the non-adhesive surface of the film.