JPH0347912Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a writing sheet that is used for electronic blackboards, whiteboards, etc. and has a surface that can be repeatedly written and erased with a predetermined marker.

2. Prior Art In recent years, in the field of educational stationery, there has been a remarkable spread of white boards or sheets that can be written on and erased repeatedly without using paper that stains hands with powder. The information drawn on the sheet can be instantly reduced to a size such as A4 that is easy to handle, so there is no need to take notes at meetings, etc., dramatically increasing the efficiency of meetings and seminars. It is attracting attention in various fields because it is said to be able to improve people's abilities.

By the way, conventional writing sheets are made of a support such as a milky white polyester film, a transparent polyester film having a white pigment layer, or a white coated paper (including synthetic paper), and are made of a tetrafluoroethylene/ethylene copolymer resin that can be written on and erased. Used is a film laminated with polyolefin or the like, or coated with a hard coat agent such as an ultraviolet curable unsaturated polyester resin, a silane resin, or an acrylic resin.

However, in such conventional writing sheets, for example, tetrafluoroethylene/ethylene copolymer is used as a writing/erasable film because of its surface resistivity.
10 ^{17 to 20} Ω, 10 ^{16 to 20} Ω for polypropylene, and 10 ¹⁴ Ω for coated acrylic UV-curable resin ^. The disadvantage is that erase scum and other floating dust in the atmosphere tend to adhere to the printer due to static electricity generated during use, resulting in extremely blurred information when copying written information.

In order to compensate for this drawback, it has been proposed to apply an antistatic agent to the back side of the writing sheet or to spray the antistatic agent onto the surface of the writing sheet, but the former method Since the antistatic effect is lost due to wear or peeling, it is not possible to sufficiently avoid the adhesion of erasing scum, dust, etc., and further improvements are desired. In the latter case, the adhesion of the antistatic agent is poor, and when writing with a marker is erased, the antistatic agent is removed along with it, so that a satisfactory antistatic effect is still not achieved.

Means for Solving the Problems The present invention was developed as a result of intensive studies to solve these problems. This is a writing sheet provided with layers.

The support used in the present invention is a white support such as a conventionally used milky white polyester film, but is not limited to this.
It may be colored. In addition, the writing-erasable resin layer may be a film layer such as a tetrafluoroethylene/ethylene copolymer, or a coating layer made of a hard coating agent such as acrylic, polyester, or silane. It may also be formed by melt-extruding a possible resin using a T-die method.

In addition, the material used for the adhesive layer is selected from polyurethane adhesives, unsaturated polyester adhesives, epoxy resins, acrylic resins, etc., depending on the relationship between the support and the material of the writable and erasable resin layer. things are selected.

In addition, as an antistatic layer, 1) a surfactant-based antistatic agent such as a quaternary ammonium salt, an aliphatic sulfonate, a polyhydric alcohol fatty acid ester, or a siloxane-based antistatic agent, which are generally used as an antistatic agent; 2) antimony-doped tin oxide, which is known as a conductive material, or titanium oxide with a conductive film of tin oxide formed on the surface; Mica plated with a metal such as Ni or Cu is dispersed in a binder such as polyester resin or acrylic resin.

Further, since the antistatic layer has transparency, the support is usually white and constitutes a so-called white plate, but if carbon black is used as the conductive material, it becomes a black plate regardless of the coloring of the support.

In addition, the antistatic layer referred to in this invention is the back side of the support,
That is, it is sufficiently effective even if it is provided on the opposite side of the writable and erasable resin layer. In this case, it is preferable to provide a PET film thereon in order to protect the antistatic layer from falling off and to improve running properties with the board surface.

EXAMPLE The writing sheet of the present invention will be explained with reference to the drawings.

FIG. 1 shows a first embodiment, in which an antistatic layer 4 is provided directly on a support 1, and then a writable and erasable resin layer 2 is provided with an adhesive layer 3 interposed therebetween.

FIG. 2 shows a second embodiment, in which an adhesive layer 3 is provided directly on the support 1, and then a writable and erasable resin layer 2 is provided with an antistatic layer 4 interposed therebetween.

To describe the method of manufacturing the writing sheet according to the above embodiment of the present invention, in the case of FIG.
A sheet of writable and erasable resin such as fluororesin or polyolefin resin with a thickness of ~100μ is prepared separately, and a sheet of support resin such as polyester, polyurethane, polypropylene, etc. is prepared, and one side of the writable and erasable resin sheet is prepared. An antistatic layer made of acrylic resin having ionic conductivity is applied to one side of the support resin sheet, and the two surfaces are bonded together (heated and pressed). Adhesion). In the case of FIG. 2, the difference is that an adhesive is applied to one side of the support and an antistatic agent is applied to one side of the writable and erasable resin sheet, and the two are bonded together so that they are in contact with each other.

In addition to pasting the film together, the writable and erasable layer can be created by applying a hard coat agent to the surface, or
It can also be manufactured by co-extruding a writable and erasable resin and an adhesive layer.

Effects of the invention According to the invention, since the antistatic agent is provided between the writable and erasable resin layer and the support, there is no risk of static electricity being generated on the writing and erasing surface, and dust and dirt will not adhere to it. When combined with a copying device, clear copies can be obtained, and when combined with an electric transmission device, there is no malfunction of the device, and stable electric transmission can be achieved.

Furthermore, since there is an antistatic layer between the layers, there is no risk of peeling or abrasion even after long-term use compared to those provided on the front or back side, so it can exhibit stable performance. can.

Furthermore, if conductive carbon black or graphite is used as an antistatic agent, the color will be black, but a white marker may be used, and when applied to electronic blackboards, electrophotographic reversal development is required as a copying mechanism.

However, with this black board, there is no need to use an expensive milky white film as a support as in the past, and an inexpensive transparent film can be used, resulting in cost reduction. Another characteristic of other black-colored boards is that indoor light, sunlight, etc. emitted by a white board causes diffuse reflection, which can cause eye strain depending on the viewing angle, but the above-mentioned black board does not have such a risk.

[Brief explanation of the drawing]

FIGS. 1 and 2 are sectional views showing embodiments of the present invention, respectively. 1...Support, 2...Writable and erasable resin layer,
3...Adhesive layer, 4...Antistatic layer.

Claims (1)

[Scope of utility model registration request] A writing sheet characterized in that an adhesive layer 3 and an antistatic layer 4 are provided between a support 1 and an erasable resin layer 2.