JPS60250990A - Original-correcting liquid for thermal stencil paper - Google Patents

Abstract

PURPOSE:To enhance lipophilicity, solubility, pigment dispersing property and non-flammability of a correcting liquid, by incorporating specified amounts of a pigment consisting of rutile-type titanium oxide and a binder consisting of a thermoplastic synthetic resin having a softening point of not lower than 80 deg.C into a solvent. CONSTITUTION:Rutile-type titanium oxide and a thermoplastic synthetic resin having a softening point of not lower than 80 deg.C are individually dispersed in solvents such as an organic solvent, e.g., toluene or ethyl acetate, and water, and the resultant dispersed liquids are mixed with each other to obtain the correcting liquid. The content of titanium oxide in terms of pigment volume fraction is set to be not lower than 3% and not higher than a value which is lower than the critical pigment volume fraction (about 55%) by at least 10%. A polyprophylene resin, a polyethylene resin or the like having a rate of chlorination of not lower than 50% is used as the thermoplastic synthetic resin. Where the solvent is water, an appropriate emulsion is added thereto to enhance the lipophilicity. In addition to the components mentioned above, other pigments, a dispersant or the like is appropriately added.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to an eraser correction fluid G for correcting typographical errors in a manuscript for thermal stencil paper. Note that the manuscript correction fluid is a film-forming coating fluid, which is applied to the corrected parts of the original manuscript and forms a uniform thin film in a very short period of time, thereby hiding and erasing the corrected parts. Furthermore, it is designed to allow you to rewrite the text by writing on top of it.

(Prior Art) In general, the characteristics required for manuscript correction fluid are (a)
) Appropriately viscous fluid (viscosity 20-150CPS)
) (b) A uniform and thin film can be formed (c) It dries quickly after application (d) It has excellent hiding power (e) The hiding film is not contaminated by art materials (the solvent in the correction fluid can damage the correction area) (f) The coating has good adhesion to the painting material.

Conventional correction fluids use rutile titanium oxide, which is white and has a strong hiding power, as a pigment, and an acrylic acid ester copolymer resin, which has a strong binding force, as a pigment binder. Solvents (benzene, toluene, xylene, etc. and histo derivatives) or paraffinic solvents (
dispersed in pentane, hexane and their derivatives),
In addition, in order to improve semi-drying properties and coating properties, there are products with a high pigment concentration containing 60% or more of the pigment in terms of weight percentage (75% or more in terms of solid content).

On the other hand, the original manuscripts to be corrected include those that were handwritten using a pencil, ballpoint pen, India ink, or ink pen, those that were typed or dot printed using carbon ribbon, those that were printed using a thermal transfer printer, and those that were dry-copied. Printed materials, offset printing, gravure printing, letterpress printing, etc. are used.

The above-mentioned correction fluid is used not only to correct the various original documents themselves, but also to obtain a large number of copies from the corrected documents. Now, methods for obtaining copies include optical methods such as dry copying, perforation copying on electronic mimeograph paper and stencil printing, electrostatic copying on photosensitive conductive paper and offset printing, and photo printing. There is a way. On the other hand, as a copying method using heat, there is a method of perforating an image on a document onto a heat-sensitive stencil paper and performing stencil printing. That is, in this method, a heat-sensitive synthetic resin film that is relatively transparent and light-transparent is laminated with a thin porous support that allows ink to pass through and whose physical properties do not change at the heating temperature required for perforating the film. Use stencil paper.

A document on which an image has been drawn with black ink that absorbs light and generates heat is brought into close contact with the film side of this base paper, and by irradiating light rays rich in infrared rays from the support side of the base paper, the image area* of the document is heated. The heat generated melts and shrinks the image-corresponding portion of the film to form a perforated image. In other words, the original image must be heated by light irradiation, and that heat must be efficiently transferred to the film.
.

(Problem to be Solved by the Invention) However, conventional correction fluids contain titanium oxide, a metal oxide with better thermal conductivity than synthetic resins, in large amounts close to (or above) the critical pigment volume fraction. The film formed by this composition is porous and has a structure in which titanium oxide particles are connected.Therefore, even if an image drawn on this film absorbs infrared rays and generates heat, it will not heat up. However, the heat diffuses quickly through the correction film, resulting in a lack of heat necessary for perforation, making it impossible to perform perforation faithful to the image on the document, making it impractical. there were.

Therefore, in general, it is a waste of time and effort to copy the original corrected with this conventional correction fluid and use the copy as the corrected original. In addition, a method has been proposed in which clear lacquer is applied to the area that has been corrected using conventional correction fluid, and then the area is corrected again using conventional correction fluid. There is a problem that not only is the quality of preventing this problem insufficient, but also that the correction work becomes troublesome.

Structure of the Invention (Means for Solving the Problems) In order to solve the above problems, in this invention, a titanium oxide pigment is added to a solvent in an amount of 10% less than its critical pigment volume fraction.
% or more in terms of pigment volume fraction, and a thermoplastic synthetic resin having a softening point of 80° C. or more as a binder.

(Function) With the above configuration, in the present invention, it is possible not only to reliably hide the erroneously written portion, but also to print the corrected characters on the concealing film with good adhesion, and also to print the corrected characters on the concealing film with good adhesion. It conducts heat efficiently to the base paper film without dispersing it, making it possible to perform clear and faithful perforation, and the base paper can be peeled off smoothly without causing fusion between the smooth base paper film and the original. correction work can be done quickly.

(Example) In the present invention, a correction solution is prepared by suspending a pigment made of rutile titanium oxide and a binder made of a thermoplastic synthetic resin having a softening point of 80°C or more in a solvent made of an organic solvent or water. was prepared.

The mixing ratio of titanium oxide is determined by its critical pigment volume fraction (approximately 55
%), the pigment volume fraction (
pvc) and preferably 3% or more. As is well known, the critical pigment volume fraction (cpvC) is the pigment volume fraction at which the binder just fills the voids between pigment particles in a dry coating. It goes without saying that if the pigment volume fraction exceeds this CPVC value, even if it exceeds (CPVC-10)%, the surface of the pigment particles cannot be completely covered by the binder particles G. Pigment particles are arranged in direct contact with each other.As a result, a porous correction liquid coating film is formed, and during heat-sensitive stenciling, the heat transferred to the corrected image on the correction liquid coating layer passes through the pigment particles. A phenomenon occurs in which the pigment is transmitted and quickly diffused.On the other hand, when the pigment volume fraction is 3
% or less, not only the erasing power of the correction liquid coating layer becomes small, but also there is a risk that the heat shielding effect will be insufficient. Therefore, in this invention, the mixing ratio of titanium oxide is P
The VC was set in the range from 3% or more to (CPVC-10)%.

In addition, as the organic solvent serving as the solvent in this invention, toluene, ethyl acetate, ethylcyclohexanol, dimethylacetamide, methyl ethyl ketone, etc. can be used. When water is used as the solvent, the glass transition temperature is 3°. In addition to using a synthetic resin emulsion at a temperature of .degree. C. or higher as a binder, the lipophilicity of the correction fluid can be increased by adding an emulsion such as polyester wax, galvana wax, or natural wax.

Further, as the binder, a thermoplastic synthetic resin having a softening point of 80'C or higher should be used. If a material with a softening point of 80°C or lower is used, the binder in the coating of the image area will be softened by the heat generated from the image during plate making (during light irradiation and perforation).
The image may easily peel off and adhere to the base paper film, clogging the perforations, or the melted and shrunk base paper film may adhere to the softened image area coating. The above-mentioned conditions can be used, and by adding them, the lipophilicity, solubility, pigment dispersibility, and flame retardance of the correction solution can be improved.

Further, in order to adjust the CPVC value, thixotropy factor, viscosity, etc., appropriate amounts of pigment components other than titanium oxide, such as lucium carbonate, sandy white, silica, and organic bentonite, can be added. The correction fluid has a thixotropy factor (CF) of 5 or less,
Those having a viscosity of 1000 centipoise or less, more preferably a CF of 1.3 to 2.0 and a viscosity of 20 to 20 centipoise are suitable for use. moreover,
It is practically desirable that the drying time to the touch is within 60 seconds. Note that the above-mentioned thixotropy factor refers to the thixotropy factor when the same rotor is used in a BH type viscometer and the rotation speed of the rotor is 6r.
*Viscosity Xl when measured at p, m, and 6 Or, p,
It is a numerical value expressed as the ratio XI//X2 to the viscosity X2 when measured in m, and each viscosity is measured at 25°C.

To prepare a correction fluid, a predetermined amount of solvent, pigment, and other solid components are added, and if necessary, an organometallic compound such as a chelate compound of titanium or aluminum is added as a dispersant to suspend the pigment. Prepare a suspension. Alternatively, a method can be adopted in which a binder suspension made of synthetic resin powder and, if necessary, the above-mentioned emulsion are separated into a solvent to prepare a binder suspension, and both suspensions are mixed.

Next, specific embodiments of this invention will be described.

(Example 1) Rutile type titanium oxide 90 parts by weight Silica powder 3 parts by weight Methacrylic acid ester acrylic ester copolymer powder 73 parts by weight Toluene 85 parts by weight Ethyl acetate 25 parts by weight Ethylcyclohexanol 15 parts by weight Mixing these A correction solution was prepared. The solid content in this correction fluid is 5
7%, viscosity was 250 centipoise, and thixotropy factor was 1.8. Furthermore, the mixing ratio of titanium oxide and binder is about 1:4. This correction fluid was used to correct the errors on the manuscript, and when a correct image was drawn on the layer coated with the correction fluid and thermal copying was performed, the result was a clear copy with no difference between the corrected portion and the non-corrected portion. I was able to get the image. The pigment volume fraction in this example was 22.5%, and the dry-to-touch time was within 60 seconds.

(Example 2) In this example, 1 weight of an aluminum chelate compound was added to 90 parts by weight of a solvent prepared by mixing toluene and trichloroethane in a ratio of 9:1, and the solid acid content was 55% by weight.
and mixed.

Then, the performance of the correction fluid was compared by converting titanium oxide in the solid component into chlorinated polyester. The specific gravity of the titanium oxide used was 4.2, and the oil absorption was 19.5.
is 55%.

Here, erasing power refers to the ability of the correction liquid coating layer to hide erroneous images, plate-making properties refer to the clarity of corrected images during thermal copying, and releasability refers to the ability of the base paper to peel off during thermal copying. It means ease. Also, @ means very good, ◯ almost no problems, △ means there are some problems, and × means there are defects. As is clear from the above results, the mixing ratio (weight ratio) of TiO2 and CPE in the solid component is 2.
It can be seen that the applicable range is a composition of 1 to 1:3.

(Example 3) 60 parts by weight of an emulsion containing 50% by weight of vinyl versatate and vinyl acetate copolymer (solvent water) 30 parts by weight of an emulsion containing 50% by weight of acrylic acid enterstyrene copolymer (solvent water) Rutile type titanium oxide 85 Parts by weight Sodium hexametaphosphate 0゜Heel weight Organic bentonite 1 part by weight Water 40 parts by weight Calcium carbonate 6 parts by weight Talc 5 parts by weight Butyl cellosolve (high boiling point solvent) 5 parts by weight Ethylene glycol) L/(high boiling point solvent) 3 Part by weight preservative 0゜1
Parts by weight In this example, an emulsion containing two types of binders was prepared in advance as described above, and a suspension was prepared by suspending titanium oxide and the other reagents mentioned above in water, and the two were mixed. I adjusted the correction fluid.

In this example, the PvC in the solid component is 34%, the viscosity is 130 centipoise, and the thixotropy factor is 1.
8, and the dry-to-touch time was within 60 seconds.

In addition, in this example, 2.5 parts by weight of a 30% by weight wax emulsion (the solvent is water) was added to the above reagent.
5 parts by weight of 30% by weight polyester emulsion (
Two types of correction fluids were prepared by adding and mixing water as a solvent. Their viscosity, thixotropy factor, dry-to-touch time, and PVC were less than 200 centipoise, less than 2, and less than 60 seconds, respectively.

Even when using each of the correction fluids in this example, it was possible to obtain a clear copy image as in each of the above examples.

Effects of the Invention -LAs detailed above, the present invention is capable of reliably concealing erroneous portions without leaving gaps, and by reducing the rate of thermal diffusion from the correction fluid coating layer to produce clear copied images. “It has excellent effects in that it can be obtained.

Patent applicant: Asia Base Paper Co., Ltd. Agent: Patent attorney Hironobu Onda

Claims (1)

[Scope of Claims] l In a document correction liquid for thermal stencil paper containing a pigment and a binder, a titanium oxide pigment is contained in a solvent in a pigment volume fraction in a range that is 10% or more less than its critical pigment volume fraction. A manuscript correction liquid for thermal stencil paper, characterized in that it contains 3% or more and a thermoplastic synthetic resin having a softening point of 80°C or more as a binder. 2. Claim 1, wherein the solvent is an organic solvent, and the binder is chlorinated polypropylene and/or chlorinated polyethylene with a chlorine content of 50% or more.
Manuscript correction fluid for thermal stencil paper as described in this section. 3 The solvent is water, and the binder has a glass transition temperature of 3.
The original correction liquid for thermal stencil paper according to claim 1, which contains a synthetic resin and wax at a temperature of 0°C or higher.