JPH0764155B2 - Sheet for whiteboard - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a whiteboard sheet.

(Prior Art) A whiteboard that has a surface of synthetic resin and uses an aqueous pen to write is already in use, but recently, by optically reading the content written on the whiteboard,
A whiteboard for copying, which enables copying by a thermal recording system or an electrophotographic system, has come into use.

However, in such a whiteboard for copying, it is necessary to change the writing surface to a sheet shape instead of the conventional plate shape, and to transfer the sheet to the back of the whiteboard while shining light to read the writing content, It is sometimes required to have flexibility, and it is also desirable that it has rigidity during writing and transportation so that it does not hinder use. When the light is strong, it is sometimes necessary to have heat resistance to withstand the heat of the light source. In addition, the same writability as that of a normal whiteboard, erasability of written contents, and abrasion resistance are required, and an antistatic treatment for preventing electrification caused by movement is also desired in some cases.

(Problems to be solved by the invention) Therefore, in the present invention, while having the same surface performance as the conventional whiteboard, it is flexible and rigid as a whole and has excellent surface wear resistance. It is intended to provide a whiteboard sheet.

(Means for Solving the Problems) The whiteboard sheet of the present invention is a “crosslinked cured film made of an ionizing radiation curable resin in which fluorine-based organic particles are added to the surface of a flexible base substrate having rigidity. It is characterized by having.

1 to 4 show an embodiment of a whiteboard sheet according to the present invention, in which the surface of a flexible base sheet 2 having rigidity is crosslinked with an ionizing radiation curable resin. 2 has a cured coating 3, and the base sheet 2 is composed of two layers as shown in FIG. 2 and is cured by ionizing radiation on a first flexible sheet 4 having rigidity and heat resistance. The flexible base sheet 2 is a laminated body in which the second flexible sheet 5 having excellent adhesion of the crosslinked cured coating of the organic resin is laminated.
3 has a pattern 6 on the surface of a flexible base sheet 2 and a cross-linking cured coating 3 of an ionizing radiation curable resin, and FIG. What is shown in (1) is one in which the first and second flexible sheets forming the flexible base sheet 2 are laminated using the adhesive layer 7.

As the flexible base sheet 2 having rigidity, polyester, polyethylene, polycarbonate, polystyrene,
Plastic films such as polyacrylonitrile, ABS, nylon, polypropylene, etc. are selected according to the usage conditions. Among them, polyester, polycarbonate,
A film of polyacrylonitrile or polystyrene is preferable because of its high rigidity.

Alternatively, as the flexible base sheet 2 having rigidity,
Metal foils such as iron, copper, tin, lead, aluminum, or stainless steel can also be used. Of these, the ones such as iron foil are convenient for fixing paper etc. on the whiteboard with a magnet. Is good.

The cross-linking cured film 3 of the ionizing radiation curable resin is a coating film of a composition mainly composed of the ionizing radiation curable resin having a cross-linked structure introduced by irradiation with ionizing radiation.

As the ionizing radiation curable resin, unsaturated polyester,
Those having an acrylic group such as polyether acrylate, polyester acrylate, epoxy acrylate, urethane acrylate and spiro acetal acrylate, polyptadiene resin, polythiol polyene resin and the like can be used.

The above ionizing radiation curable resin can be used alone, but in order to improve the curability and the hardness of the cured coating film, it is advisable to add a polyfunctional monomer, such as trimethylolpropane triacrylate, pentaerythritol triacrylate, or diester. Trifunctional monomers such as pentaerythritol hexaacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate,
Diethylene glycol diacrylate, or 1,6-
Bifunctional monomers such as hexanediol diacrylate,
Alternatively, it can be appropriately selected from tetrafunctional, pentafunctional or hexafunctional monomers and used.

In addition, various additives may be added to the ionizing radiation curable resin, but when ultraviolet rays are used for curing, a photoinitiator,
For example, acetophenones, benzophenone, Michler's ketone, benzoin, benzylmethyl ketanol, benzoyl benzoate, α-acyloxime ester, tetramethylthiuram monosulfide, or thioxanthones, or as an ultraviolet sensitizer, n-butylamine, triethylamine, Alternatively, tri-n-butylphosphine or the like can be added.

It is desirable that a composition mainly composed of an ionizing radiation-curable resin contains a matting agent for the purpose of adjusting the gloss of the coating film after curing. As the matting agent, inorganic particles such as silica, calcium carbonate, and precipitated barium carbonate, or organic particles such as fluorine particles and polyethylene particles can be used. Of these matting agents, it is preferable to use organic particles such as fluorine-based particles from the viewpoint of improving the erasability of written contents and abrasion resistance.

A composition mainly composed of an ionizing radiation curable resin can be prepared by a conventional coating method such as blade coating, gravure coating, rod coating, knife coating, reverse roll coating, kiss coating,
It is applied to the surface of the flexible substrate sheet 2 by a method such as spray coating or offset gravure coating.

After coating, the coating film is cross-linked and cured by irradiation with ionizing radiation using ultraviolet rays or electron beams.

As the electron beam, Cockloft-Walton type, Van de Graaff type, resonance transformer type, insulating core transformer type, linear type, dynamitron type, emitted from various electron beam accelerators such as high frequency type, 50 to 1000 KeV, preferably An electron beam with an energy in the range of 100 to 300 KeV is used, and as the ultraviolet rays, those emitted from an ultraviolet source using an ultra-high pressure mercury lamp, high pressure mercury lamp, low pressure mercury lamp, carbon arc, xenon arc, or metal halide lamp lamp are used. To use.

By thus introducing the crosslinked structure, the erasability and abrasion resistance of the written contents are improved while maintaining flexibility.

In the case of electron beam curing, irradiation is performed in an inert gas or by laminating a film in order to cure by blocking oxygen in order to recommend a curing reaction, but in the case of ultraviolet curing, these measures are usually not required. Curing progresses. However, when surface properties of the coating film are required as in the present invention, it is more effective to use an inert gas and a film in the same manner as described above even in ultraviolet curing.

The whiteboard sheet of the present invention has the basic structure as described above, but can take various modes as illustrated in FIGS. 2 to 4.

In the structure shown in FIG. 2, the flexible base sheet is formed by laminating the first and second flexible sheets, and the first flexible sheet 4 has rigidity and heat resistance. The second flexible sheet 5 has excellent adhesion of the cross-linking cured film of the ionizing radiation curable resin as the upper layer. The material of the first flexible sheet 4 is, in principle, the same as that of the material of the flexible base sheet 2 having rigidity. Also, the second
The material of the flexible sheet 5 is selected in consideration of the material forming the cross-linking cured coating of the ionizing radiation curable resin of the upper layer, but in many cases, a film or sheet mainly composed of polyvinyl chloride resin Is preferably used. A film or sheet mainly composed of polyvinyl chloride resin is composed of polyvinyl chloride resin and a plasticizer, etc. if necessary. When the plasticizer is added, the polyvinyl chloride resin 10
It is preferably 30 parts by weight or less with respect to 0 parts by weight, and more preferably 10 parts by weight or less in terms of heat resistance and rigidity. It is also possible to use a resin type modifier such as ABS resin in the sense of imparting further heat resistance and rigidity.

Regarding the thickness of the first and second flexible sheets, the first flexible sheet has a thickness of 25 to 200 μm, preferably 25 to 100 μm, and the second flexible sheet has a thickness of 30 to 500 μm, preferably 50 to 200 μm.
m. Therefore, the thickness of the flexible base sheet 2 is 55 to 70.
It is 0 μm, preferably 100 to 350 μm.

The first and second flexible sheets may be laminated by adhering them by an appropriate method. For example, solvent-based vinyl-based, acrylic-based, polyamide-based, epoxy-based adhesives,
It is preferable to use a dry laminating method using a rubber type or a polyurethane type.

The whiteboard sheet of the present invention includes, for example, layers 2, 5,
Patterns 6 such as scales, grids, letters, etc. may be provided at appropriate positions of 5, and if this is done, it becomes the target of the writing position, the frame such as the monthly calendar is set, the date and day of the week are set. It is preferable that the entry position can be indicated.

As the ink used for printing, a vehicle obtained by kneading a pigment or dye colorant in a vehicle, a plasticizer, a stabilizer, other additives, a solvent or a diluent is used, and as the vehicle, for example, ethyl cellulose, ethyl hydroxyethyl cellulose, Cellulose acetate propionate,
Cellulose derivatives such as cellulose acetate, polystyrene,
Styrene resin and styrene copolymer resin such as poly-α-methylstyrene, homo- or copolymer resin of acrylic or methacrylic resin such as polymethyl methacrylate, polyethyl methacrylate, ethyl polyacrylate, butyl polyacrylate, rosin, rosin Modified maleic acid resin, rosin modified phenolic resin, rosin ester resin such as polymerized rosin, polyvinyl acetate resin, coumarone resin, vinyltoluene resin, vinyl chloride resin, polyester resin, polyurethane resin, butyral resin, etc. A gravure printing method, an offset gravure printing method, a silk screen printing method, an offset printing method, or the like can be used to print and form a pattern using the above ink.

It is also effective to subject the whiteboard sheet of the present invention to antistatic treatment. In particular, since the whiteboard sheet of the present invention is transported during copying, the electric charge is likely to be accumulated. Therefore, it is preferable that either the front surface or the back surface of the whiteboard sheet or both surfaces thereof be subjected to antistatic treatment. , Especially on the back side (in the case of FIG. 1, the flexible base sheet 2
The antistatic treatment may be applied to the lower surface side of the above, and in the case of FIGS. 2 to 4, the lower surface side of the first flexible sheet 4).

The antistatic treatment can be achieved by various methods. For example, it may be coated with an antistatic agent or kneaded into a sheet.

As the antistatic agent, various cationic, anionic, nonionic or amphoteric surfactants, inorganic materials such as metal powder, carbon powder or graphite, or siloxane coating agents can be used.

(Effects of the Invention) Since the whiteboard sheet of the present invention has the above-described structure, it has the same surface performance as a conventional whiteboard, but it is flexible and therefore easy to transfer by rolls or the like. Since it has rigidity, it does not hinder transfer or other handling, and since the surface has a cross-linking cured coating of ionizing radiation curable resin to which fluorine-based organic particles are added, abrasion resistance of the surface, writing Excellent erasability of contents.

(Example) A polyvinyl chloride ink (manufactured by Showa Ink Mfg. Co., Ltd., orange) was used on the surface of a 100 μm thick white polyvinyl chloride film (Riken Vinyl, plasticizer 5PHR), and it was gravure-printed in 50 mm vertical and horizontal directions. Printed a grid of lines.

Then, a urethane acrylate UV-curable resin paint (Seika Beam manufactured by Dainichiseika Co., Ltd.) with Teflon powder added for the purpose of matting and improving abrasion resistance was gravure coated on the printed surface of the white polyvinyl chloride film. To a thickness of 10μ, and after coating, a 25μ thick polyester film (Toray, Lumirror T-60) is laminated and then underneath the ozone-generating UV lamp 2 with an output of 160W / cm. Through which the coating film was irradiated with ultraviolet rays to cure the coating film, and the polyester film was peeled off.

The thickness of the obtained printing / coating agent film on the back side
100μ polyester film (Toray, Lumirror 100
μ) is dry-laminated with a polyurethane adhesive (Takelac A-375 / Takenate A-3, Takeda Products Co., Ltd.), and an antistatic ink (manufactured by Showa Ink Manufacturing Co., Ltd.) on the non-laminated surface of the polyester film. Was gravure coated.

The whiteboard sheet obtained as described above was excellent in writability and erasability with a water-based pen, and the heat resistance and rigidity of the entire sheet were sufficient, and there was no problem in transporting using a roll.

Moreover, there was no contamination even after writing and erasing 5000 times repeatedly with a whiteboard marker (manufactured by Pilot). However, when the polyester film was cured without being stuck on the coated surface, contamination occurred after 1000 times.

Further, in this example, since the antistatic treatment was performed, there was no trouble due to charging.

[Brief description of drawings]

1 to 4 are sectional views showing an embodiment of the present invention. 1 ... Whiteboard sheet 2 ... Flexible base sheet 3 ... Cross-linking cured film 4 ... First flexible sheet 5 ... Second flexible sheet 6 ... Pattern, 7 ... Adhesion Agent layer

Claims (5)

[Claims] 1. A surface of a flexible base sheet having rigidity,
A whiteboard sheet having a crosslinked cured film made of an ionizing radiation curable resin to which fluorine organic particles are added. 2. The whiteboard sheet according to claim 1, wherein the base sheet is subjected to an antistatic treatment. 3. The whiteboard sheet according to claim 1, wherein the base sheet is a laminate of flexible base sheets having two layers of rigidity. 4. The whiteboard sheet according to claim 1, wherein at least one layer of the base sheet is made of a metal foil having a magnet adsorbing property. 5. The substrate sheet according to claim 1, wherein the substrate sheet has a pattern which can be seen through from the surface.
The whiteboard sheet according to any one of items to (4).