JPH03262693A - Correctable writing sheet - Google Patents

Abstract

PURPOSE:To simply correct or erase a printed image part and a writing part by applying printing to the surface roughened chemical mat layer having predetermined roughness on a base film and providing an overcoat layer with predetermined thickness thereon and roughening the uppermost layer so as to have predetermined roughness. CONSTITUTION:A writing sheet consists of a base film 1, the chemical mat layer having required printing applied thereto provided at least to the single surface of the base film 1 and an overcoat layer 3 having transparency. The center line average roughness of chemical mat layer 2 is 0.5 - 1.3mum and the ratio of the thickness of the overcoat layer 3 to the center line average roughness of the chemical mat layer 2 is 0.02 - 0.4 and the center line average roughness of the uppermost layer is 0.4 - 1.2mum. As the base film 2, a polyester film is especially pref. The chemical mat layer 2 is not especially limited so far as it is composed of a layer capable of withstanding an arbitrary erasing solution or solvent and recordable by various writing techniques and writing utensils. When the center line average roughness of the chemical mat layer 2 is below 0.5mum, no sufficient density is developed at the time of the writing due to a pencil. When the center line average roughness thereof exceeds 1.3mum, the carbon powder of a pencil is scattered and a surface is contaminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a method for improving the writability of printed image parts such as grid printing, ruled line printing, frame printing, etc. that have been printed in advance, and writing parts such as written characters, charts, and figures. The present invention relates to a writing sheet that can be easily modified or erased as necessary without damaging the writing sheet.

In conventional technical design and drafting work, it is often necessary to later correct or erase written characters, diagrams, and figures. For example, if you rub it repeatedly with an eraser or sand rubber to erase unnecessary writing, or wipe it off with a cleaning solvent such as thinner, pre-printed grid printing, ruled line printing, frame printing, etc. Even parts of the image were erased or faded, which was very inconvenient. For this reason, when the sheet is transparent, techniques such as printing on the side opposite to the writing surface (back side) or using special ink with good abrasion resistance have been devised. In either case, there is a drawback that restrictions are imposed upon printing and use.

In addition, a sheet has been proposed in which a desired print image is printed on the sheet in advance using ink, and then a transparent writing layer is formed on the surface of the sheet (1986).
2-134777), but it is extremely difficult to correct the printed image itself, and even if it were possible to correct it, the sheet surface in the corrected area would lose its writability, so it is not completely satisfactory. I can't say that.

Problems to be Solved by the Invention The present invention overcomes the drawbacks of such conventional writing sheets, and without impairing the writing properties, the printed image portion and
The purpose of this invention is to provide a writing sheet on which written parts such as characters, charts, figures, etc. can be easily corrected or erased as necessary.

Means for Solving the Problems The present inventors have conducted various studies to develop a correctable writing sheet having the above-mentioned favorable properties.
By printing on a roughened chemical mat layer with a predetermined roughness provided on the base film, further providing an overcoat layer with a predetermined thickness on top of that, and roughening the top layer to a predetermined roughness. The inventors have found a way to achieve this objective, and have completed the present invention based on this knowledge.

That is, the present invention comprises a base film, a chemical matte layer which is applied to at least one side of the base film and which is subjected to necessary printing, and a transparent overcoat layer which is applied on the chemical matte layer, and the center line average roughness of the chemical mat layer is 0.5 to 1.3 μm, and the ratio of the thickness of the overcoat layer to the center line average roughness of the chemical mat layer is 0.02 to 0.4. hand,
Moreover, the present invention provides a correctable writing sheet characterized in that the center line average roughness of the uppermost layer is 0.4 to 1.2 μm.

The present invention will be explained in detail below.

Examples of the base film used in the present invention include plastic films such as polyethylene, polypropylene, polycarbonate, polyester and polysulfone films, and polyester films are particularly preferred. This base film is preferably one in which one or both sides of the film base material have been previously subjected to an adhesion treatment or have been provided with an anchor (undercoating) coating.

In the present invention, the chemical matte layer applied to one or both sides of the base film can withstand any erasing liquid or solvent used to erase printed parts such as sections, and can be used with various writing methods and writing instruments. There is no particular restriction as long as it has a layer on which characters, drawings, diagrams, etc. can be recorded, and examples of such materials include those mainly composed of fillers, binders, and solvents such as water and organic solvents. be able to. Examples of this filler include silica, calcium carbonate, kaolin, clay, and aluminum hydroxide. The binder is generally one that has strength and solvent resistance, such as acrylic resin, styrene resin, melamine resin,
Examples include urea resin. Examples of the organic solvent include methanol, ethanol, cellosolve, and methyl cellosolve.

Furthermore, this chemical mat layer has a roughened surface with unevenness, and its center line average roughness is usually 0.5-1.3.
pm, preferably selected in the range of 0.6-1.0μ+++. If the center line average roughness is less than 5 μm, sufficient density will not be obtained when writing with a pencil. Moreover, if the thickness exceeds 1.3 μm, carbon powder will scatter when writing with a pencil, inevitably contaminating the surface.

Printed images such as grid printing, ruled line printing, border printing, character printing, etc. are usually applied to this chemical mat layer using ordinary printing ink, ultraviolet curing type gravure printing ink, offset printing ink, or the like.

In the present invention, the overcoat layer applied to one or both sides of the chemical mat layer has transparency and appropriate hardness, protects the printed image, can withstand erasing of the written part with an eraser, etc., and has a high density of the printed image. There is no particular restriction as long as it can maintain the properties well, and examples of such materials include those mainly consisting of a curable soluble resin, a resin emulsion, and a solvent such as water or an organic solvent. As this curable soluble resin, thermosetting, photocuring, and electron beam curing are usually used, such as water-soluble resins such as melamine resin, epoxy resin,
Examples include oil-soluble ones such as incyanate resin. Examples of the resin emulsion include polyacrylic emulsion, polystyrene emulsion, and polyvinyl acetate emulsion.

Examples of the organic solvent include ethanol, methanol, isopropyl alcohol, and cellosolve.

Further, the overcoat layer is selected so that its thickness is usually in a ratio of 0.02 to 0.4, preferably 0.04 to 0.2, with respect to the centerline average roughness of the chemical mat layer.

If this ratio is less than 0.02, the overcoat will not have sufficient strength and, for example, if an eraser is used, the printed lines will disappear. Moreover, if it exceeds 0.4, the unevenness of the matte layer becomes small, and the writability with a pencil or the like deteriorates.

The thickness of this overcoat layer is usually 0.01 to 0.5
μm1 is preferably 0.02 to 0.3 μm.

This overcoat layer can contain optional additive components such as an antistatic agent and a binder resin for improving toner adhesion. Examples of the antistatic agent include quaternary ammonium salt type cation type, betaine base amphoteric type, phosphate ester type anion type, and the like. Examples of the binder resin include polyacrylic emulsion, styrene acrylic emulsion, and water-soluble melamine resin.

In the present invention, the surface roughness of the uppermost layer is generally 0.4 to 1.2 μm, preferably 0.4 to 1.2 μm, in terms of center line average roughness.
It is necessary to keep the thickness within the range of 6 to 1.0 μm. If the surface roughness is less than 0.4 .mu.m, the density when writing with a pencil will not be sufficient, and if it exceeds 1 or 2 .mu.m, carbon powder will scatter during writing with a pencil and the surface will inevitably become contaminated.

Further, to explain the present invention with reference to the accompanying drawings, FIGS. 1 to 4 are cross-sectional views of different examples of the writing sheet of the present invention, and FIG. Figures 2 to 4 show examples in which the cut layer 2 and overcoat layer 3 are provided, and each layer is provided on both sides of the base film. Figure 2 shows the case of double-sided printing, and Figure 3 shows the case of single-sided printing. In this case, FIG. 4 shows the case where one side is printed and there is no overcoat layer on the opposite side (back side) to the printed side.

In the plan, 1 is a base film, 2 is a chemical mat layer whose surface is roughened so that even if a part of the printed image is erased, it can be written on the erased part, and 3 is an unevenness of the rough surface of the chemical mat layer. The overcoat layer is formed in a concavo-convex shape corresponding to P, and P is a printed image.

Next, to explain one example of the manufacturing method of the sheet of the present invention, a water-based chemical matte liquid is applied to the surface of the base film 1, which has been previously subjected to an adhesion treatment, and a heat treatment is performed to form a roughened chemical mat layer. 2 is formed, sections and the like are printed on this chemical mat layer by a gravure method or the like, and then a water-alcohol overcoat liquid is applied and heated and dried to form an overcoat layer 3.

As this coating method, for example, gravure coating, roll coating, reverse coating, smoothing coating, bar code method, etc. can be used.

A curable resin is usually used as the resin component of the chemical matte liquid or overcoat liquid, and irradiation with electron beams, gamma rays, ultraviolet rays, etc., and heat curing are generally used as means for curing the resin. Electron beam irradiation is performed using, for example, a curtain-type scanning accelerator, and ultraviolet irradiation is performed using, for example, a mercury lamp,
This is done using metal halide lamps, xenon lamps, etc.

Effects of the Invention The sheet of the present invention can print image parts such as grid printing, ruled line printing, frame printing, etc. that are pre-printed without impairing writability, and writing parts such as written characters, diagrams, figures, etc. as necessary. can be easily modified or deleted.

In other words, by rubbing with an eraser, you can erase only the written part without damaging the printed image part.
It has no effect on the image part, and the printed image part can be erased by using an appropriate correction fluid when necessary, and even after erasing, it has the remarkable effect of not impairing printability in any way. .

Furthermore, in the case where both sides of the film are processed in the sheet of the present invention, image parts can be printed on both sides of the sheet, so it is possible to modify and erase each printed image part separately. It's convenient.

In addition, when the overcoat layer contains an antistatic agent, it can effectively discharge static electricity generated when wiping written records, prevent dust, etc. from adhering, and can be used repeatedly. Example Next Example The present invention will be explained in more detail below.

Example 1 A thermosetting water-soluble resin (melamine/formalin condensation resin), a resin emulsion (acrylic acid ester copolymer), and an inorganic photonic agent fine particle (silicon dioxide) were applied to both sides of a 50μ thick polyester film that had been pre-adhesively treated. A water-based chemical matting solution consisting of an aqueous medium containing a curing catalyst (NH, Cl2), a surfactant, etc. is uniformly applied to the entire surface using a roll coating method, and heated to a thickness of 5.
A chemical mat layer having a thickness of 10 μm and a center line average roughness of 0.7 μm was formed to obtain a chemical mat film.

Next, on one side of the chemical mat layer obtained in this way, a 1+m grid section is printed using a gravure method, and then an overcoat liquid having the following composition is applied to both sides to a thickness of 0.5 to 1. It was coated using a barcode method to a thickness of 5 μm and dried by heating.

Overcoat liquid acrylic ester copolymer 9.3 Melamine
Formalin condensation resin 3.0 curing catalyst
0.3 water
57,4 ethanol
30.0 total 100.0 Example 2 A chemical matte film was obtained in exactly the same manner as in Example 1.

Next, on one side of this chemical mat layer, the composition ratio of water in the overcoat liquid was changed to 52.8% by weight, and 4.6% by weight of an anionic antistatic agent (Chemistat 6120 (manufactured by Sanyo Chemical Co., Ltd.) was added). The overcoat liquid was applied and dried by heating in the same manner as in Example I, except for the following steps.

Example 3 A chemical matte film was obtained in exactly the same manner as in Example 1.

Next, the same procedure as in Example 2 was carried out, except that the same amount of styrene-acrylic copolymer for improving toner adhesion was added to one side of this chemical mat layer in place of the anionic antistatic agent in the overcoat liquid. Apply overcoat liquid and heat dry! child.

Comparative Example 1 A chemical matte film was obtained in exactly the same manner as in Example 1.

Next, a 1 mm grid section was printed on one side of this chemical mat layer using a gravure method to obtain a chemical mat film f-0. Methyl isobutyl ketone 50.0 Toluene 30.0 Xylene 16.0 Polyester resin 3.0 Incyanate resin 1.0 Total 100.0 A section of 111111 squares was printed on one side of the adhesive layer using a gravure method, and then a chemical matte layer was formed on that side in exactly the same manner as in Example 1 to obtain a chemical matte film.

Next, the physical properties of each sample obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were evaluated by the following test method.

(1) Durability of the printed surface The surface of the sheet having the printed image was strongly rubbed 10 times with a plastic eraser, and the remaining density of the printed image was visually judged on the following three scales.

○: Good △: Slightly poor ×: Extremely poor (2) Erasability of printed surface The surface of the sheet with the printed image was rubbed with Somar's PPC correction liquid Elmar corrector, and the ease of erasing the printed image was evaluated as follows: Judged in stages.

○: Good △: Slightly poor ×: Extremely poor (3) Sheet re-editability After rubbing the surface of the sheet with the printed image with Somar's PPC correction liquid Elmer corrector and erasing the printed image, it was used for Mitsubishi Uni-HBO 15mm core. The extent of the additions made to the sheet and the additions made to the sheet with the printed image were visually determined as follows.

○: Good :Cannot be evaluated The results are shown in the table below.

[Brief explanation of drawings]

1 to 4 are cross-sectional views showing different examples of the writing sheet of the present invention. 1... Base film, 2... Chemical mat layer, 3
...Overcoat layer

Claims (1)

[Scope of Claims] 1. Consisting of a base film, a chemical matte layer with required printing applied to at least one side of the base film, and a transparent overcoat layer applied on the chemical matte layer. , and the center line average roughness of the chemical mat layer is 0.5 to 1.3 μm, and the ratio of the thickness of the overcoat layer to the center line average roughness of the chemical mat layer is 0.02 to 0.4. A correctable writing sheet characterized in that the centerline surface roughness of the uppermost layer is 0.4 to 1.2 μm. 2. The sheet according to claim 1, wherein the overcoat layer contains an antistatic agent. 3. The sheet according to claim 1 or 2, wherein the overcoat layer contains a binder resin for improving toner adhesion.