JP2979069B2 - OHP sheet for electrostatic dry copier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pen and a pen using a water-based ink in a light-transmissive recording medium for recording using an electrostatic dry copying machine, in particular, an OHP (over head projector) sheet. The present invention relates to a sheet which can be recorded with a writing instrument such as a pen for plotting and a pen for plotting.

[0002]

2. Description of the Related Art Conventionally, sheets which have been used for OHP printing and the like using an electrostatic dry copying machine include a method in which a surface of a substrate made of a transparent plastic film is subjected to a surface treatment such as an antistatic treatment. In some cases, a surface roughening treatment is performed to improve the fixing property of the toner, or a hydrophobic resin is applied, and a toner fixing layer is provided thereon.

[0003] However, the above-mentioned conventional sheets have no or poor water-absorbing property of the aqueous ink.
Write characters using a writing instrument such as an aqueous ballpoint pen,
Or, if you try to apply a color, it will dry very slowly, so it will stick to your hands and become dirty, and when you overlap the sheet, water-based ink will adhere to the back of the sheet and the image will bleed, making it unusable. It was not enduring. Therefore, when writing or coloring on the OHP sheet, a special oil-based felt-tip pen had to be used.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a method of writing or painting a sheet directly on a printing surface of a sheet by using a commercially available ordinary water-based felt-tip pen or water-based ballpoint pen. SUMMARY OF THE INVENTION It is an object of the present invention to provide an OHP sheet for an electrostatic dry copying machine which is free from the above-mentioned disadvantages, has excellent water ink absorption, quick drying properties, and is excellent in water resistance. is there.

[0005]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above-mentioned problems, and its structure is as follows.
In an OHP sheet for an electrostatic dry copying machine having a toner fixing layer provided on a substrate made of a transparent plastic film, the resin forming the toner fixing layer has an acetalization degree of 2 to 40 mol%. It is characterized by being a polyvinyl acetal resin. That is, the inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a polyvinyl acetal having a specific value of acetalization degree in a resin forming a toner fixing layer provided on a transparent plastic film. By using a water-based resin, the water-based ink has excellent absorption and quick-drying properties, has good water resistance, and has excellent affinity for a binder resin contained in the toner. We knew and completed the present invention.

Hereinafter, the present invention will be described in detail. The OHP sheet for an electrostatic dry copying machine of the present invention is obtained as follows. As the transparent plastic film used as the substrate, a transparent thermoplastic resin film, a polyvinyl alcohol film, a cellulose derivative film, a stretched film thereof, or the like is used. Examples of transparent thermoplastic resin films include polyethylene terephthalate, polypropylene, polyvinyl chloride, and polymethyl methacrylate.
And a film having a subbing layer for improving the adhesion between the resin surface and the toner fixing layer and a film having been subjected to corona discharge machining or the like. . However, in general, it is preferable to use a polyethylene terephthalate film having high heat resistance.

As a resin for forming a transparent toner fixing layer on the base material, a polyvinyl acetal resin obtained by reacting polyvinyl alcohol with an aldehyde to form an acetal is used. However, this resin is suitable for use because by limiting the degree of acetalization to a specific range, it becomes excellent in absorbency of water-based ink, excellent in quick drying, and excellent in water resistance. ing. Among them, aromatic aldehydes are particularly preferably used because they have the above-mentioned properties and have a good affinity for the binder resin contained in the toner. Aceta
The degree of oxidation generally ranges from 2 to 40 mol%, preferably from 5 to 20 mol. If the degree of acetalization is too low, the water-based ink absorbability and quick-drying properties are good, but the water resistance is poor. If the degree of acetalization is too high, the water resistance is good. The absorption and quick-drying of the water-based ink deteriorate.

In addition, in order to prevent blocking when sheets are stacked and to improve adhesion to toner, inorganic and organic fillers are mixed into the toner fixing layer to such an extent that transparency is not impaired. You may let it. Inorganic fillers include calcium carbonate, magnesium carbonate, zinc oxide,
Examples include titanium oxide, mica, clay, silica powder, colloidal silica, and diatomaceous earth. Examples of the organic filler include polyethylene, polystyrene, and acrylic resin.

Next, a means for forming a toner fixing layer on a base material is disclosed in Japanese Patent Application Laid-Open Publication No. HEI 9-157572, which is prepared by dissolving the resin in an aqueous solution or a mixed solvent such as water / IPA (isopropyl alcohol). Means, such as a wire bar method, a doctor blade method, or an air knife method, is applied to a transparent plastic film as a base material so as to have a predetermined thickness, and dried to obtain a desired OHP sheet. can get. In the above process, it is needless to say that antistatic treatment may be performed for the purpose of antistatic.

[0010]

As described above, the OHP sheet for an electrostatic dry copying machine according to the present invention is prepared by coating a resin for forming a toner fixing layer on a transparent plastic film as a base material by a known means. It is obtained by processing and drying, and is extremely excellent in transparency as a whole sheet.

In the present invention, the binder resin contained in the toner is added to the polyvinyl acetal resin constituting the toner fixing layer, in addition to the water absorbing property, quick drying property and water resistance of the aqueous ink. The affinity between the toner and the sheet after printing is strong because of its excellent affinity with the toner. Furthermore, recording is carried out with a writing implement using a water-based ink such as a water-based sign pen or a water-ball pen, which is generally commercially available. You can do it.

[0012]

Next, an embodiment of the present invention will be described. Example 1 Aromatic polyvinyl acetal resin (S-LEC KX-1
(Solid content 8%, degree of acetalization 8 mol%, manufactured by Sekisui Chemical Co., Ltd.)
50% by weight (hereinafter referred to as "parts") was dissolved in 50 parts of a 40/60 aqueous solution of IPA / water to prepare a coating solution. Apply this coating solution to the application
A transparent polyethylene terephthalate film having a thickness of 100 μm was coated using a tar and dried in a constant-temperature dryer at 100 ° C. for 3 minutes to obtain an OHP sheet as an example of the present invention. The toner fixing layer of this sheet is completely transparent and has a thickness of 3 μm.
Met. In the OHP sheet obtained as described above,
Copying and printing with an electrostatic dry copying machine (XJ-D70, manufactured by Fuji Xerox Co., Ltd.) revealed that an image having strong adhesion between the toner fixing layer and the toner was formed on the sheet. Next, a character is written on the above-mentioned sheet with a commercially available water-based color felt-tip pen. Immediately thereafter, even if the character is rubbed with a finger, no bleeding or run-off occurs, and the water-based ink is instantly absorbed. It was confirmed that it was dried. Further, when the above sheet is set on an overhead projector and an image is projected on a screen, a clear image is projected, and the primary colors of the aqueous color felt-tip pen are clearly projected with high density. Was.

Example 2 A polyvinyl acetal obtained in the same manner as in Example 1
0.3 part of synthetic silica powder was added to 100 parts of a resin solution, and dispersed in a ball mill for 24 hours to obtain a coating liquid, which was applied to a transparent polyethylene terephthalate film having a thickness of 75 μm.
Coating was carried out using a tar and dried in a constant temperature drier at 100 ° C. for 3 minutes to obtain another example of the OHP sheet of the present invention. Printing was performed on the obtained OHP sheet with the same copying machine as in Example 1, and writing was performed with an aqueous color marking pen. As a result, the same good results as in Example 1 were obtained.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 7/00 B41M 5/00

Claims (2)

(57) [Claims] 1. An OHP for an electrostatic dry copying machine comprising a toner fixing layer provided on a substrate made of a transparent plastic film.
In the sheet, the resin forming the toner fixing layer is a polyvinyl acetal resin having a degree of acetalization of 2 to 40 mol%.
G. 2. The OHP sheet according to claim 1, wherein the polyvinyl acetal resin is an aromatic polyvinyl acetal.