JPH0347913Y2 - - 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. Since the information drawn on the sheet can be instantly reduced to a size such as A4 that is easy to handle, 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 enhance 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 made of polyolefin resin or the like, or a synthetic resin layer made of 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 is effective when the antistatic agent is applied during driving. Since the antistatic effect is lost due to wear or peeling off, it is not possible to sufficiently avoid the adhesion of erasing scum, dust, etc., and further improvements are desired. In addition, in the latter case, the adhesion of the antistatic agent to the writable and erasable layer is poor;
When erasing something written with a marker, the antistatic agent is also removed, and 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 characterized by being joined by an intermediate layer 3 of.

The support used in the present invention is a conventionally used white support such as a milky white polyester film, but is not limited thereto, and may be a colored support. The writable and 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.
Alternatively, these writable and erasable resins may be melt-extruded using a T-die method. .

Further, the material used for the intermediate layer is appropriately selected from polyurethane resin, unsaturated polyester resin, epoxy resin, acrylic resin, etc., depending on the relationship between the support and the material of the writable and erasable resin layer. be done.

As a means of imparting antistatic properties to the intermediate layer,
The adhesive used for the intermediate layer itself has a volume resistivity.
A material having a conductivity of 10 ¹⁰ Ω-cm or less may be used, or a conductive material or an antistatic agent as described below may be added.

1) antimony-doped tin oxide-based materials, 2) titanium oxide with a tin oxide-based conductive film formed on the surface, 3) transparent conductive materials such as mica plated with metal such as Ni or Cu; ) Polymer electrolytes (surfactants) such as quaternary ammonium salts 2) Antistatic agents such as siloxane, metal powders such as Cu and Ni, metal fibers, conductive carbon black, graphite, etc. Examples include conductive materials.
When a transparent conductive material is used, the support is usually white, forming a so-called white plate, but when a colored conductive material such as carbon black is used, it is considered a black plate regardless of the coloring of the support. Become. Note that the single intermediate layer having antistatic properties as used in the present invention is sufficiently effective even if it is provided on the back side of the support, that is, on the opposite side of the writable and erasable resin layer. In this case, it is preferable to provide a PET film on the adhesive layer in order to protect the single intermediate layer having antistatic properties 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.

In the figure, a single intermediate layer 3 having antistatic properties is interposed between a support 1 and a writable and erasable resin layer 2.
Both are joined.

Regarding the manufacturing method of the above-mentioned writing sheet of the present invention, for example, a sheet of writeable and erasable resin such as fluorine resin or polyolefin resin with a thickness of about 5 to 100 μm is formed, and a support of polyester, polyurethane, polypropylene, etc. is separately prepared. A body resin sheet is prepared, an adhesive having antistatic properties is applied to one or both of the bonding surfaces, and the two are bonded together (heat-press bonding). In addition to laminating films together, the writable and erasable layer can also be manufactured by applying a hard coat agent to the surface thereof, or coextruding the writable and erasable resin and the intermediate layer using a T-die method. .

Effects of the invention According to the invention, since a single intermediate layer having antistatic properties 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 When used in combination with a copying device, clear copies can be obtained, and when used in combination with an electric transmission device, there is no malfunction of the device and stable electric transmission can be achieved.

In addition, since there is a single intermediate layer with antistatic properties 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 is stable. It is possible to demonstrate high performance.

Furthermore, if conductive carbon black or graphite is used as the conductive material, the color will be black, but a white marker may be used, and when applied to an electronic blackboard, 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 feature of black-colored boards is that white boards reflect diffusely from indoor light, sunlight, etc., which can cause eye strain depending on the viewing angle, but the above-mentioned black board does not have such a risk.

Furthermore, the present invention requires fewer manufacturing steps than when the antistatic layer and adhesive layer are provided separately, and it is possible to manufacture products that are thinner and lighter, which will help expand the market by reducing costs. It is also possible to realize this.

[Brief explanation of the drawing]

The figure is a sectional view of an embodiment of the present invention. 1...Support, 2...Writable and erasable resin layer,
3...Single intermediate layer having antistatic properties.

Claims (1)

[Scope of utility model registration request] A writing sheet characterized in that a support 1 and an erasable resin layer 2 are joined by a single intermediate layer 3 having antistatic properties.