JPS61270197A - Sheet for white board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a whiteboard sheet.

(Prior art) Whiteboards that have a surface made of synthetic resin and that use water-based pens to write on are already in use, but recently, whiteboards that optically read what is written on the whiteboard have been developed.
Copying whiteboards that can make copies using thermal recording methods, electrophotographic methods, etc. have come into use.

However, in such copying whiteboards, the writing surface is a sheet instead of a conventional plate, and the sheet must be transported to the back of the whiteboard while shining light to read the written content. Flexibility is sometimes required, but it is also desirable to have rigidity when writing or transporting, so that there is no problem when using it, and when the light is strong,
Heat resistance to withstand the heat of the light source is sometimes necessary, and
It is required to have the same writability as a normal whiteboard, the ability to erase written content, and abrasion resistance, and in some cases, antistatic treatment is also desired to prevent charging caused by movement.

(Problems to be Solved by the Invention) Therefore, the present invention has the same surface performance as a conventional whiteboard, but is also flexible and rigid as a whole, and has an excellent surface abrasion resistance. The company aims to provide whiteboard sheets with a wide range of colors.

(Means for solving problems) The whiteboard sheet of the present invention is as follows.

It is characterized by having a cross-linked cured coating of ionizing radiation-curable resin on the surface of a rigid, flexible base sheet.

1 to 4 show embodiments of the whiteboard sheet of the present invention, and the one shown in FIG. 1 has a cross-linked ionizing radiation-curable resin on the surface of a rigid flexible base sheet 2. In the case shown in FIG. 2, the base sheet 2 is composed of two layers, and a first flexible sheet 4 having rigidity and heat resistance is coated with ionizing radiation. The flexible base sheet 2 is a laminate in which a second flexible sheet 5 with a cross-linked cured coating of a curable resin is laminated.
The one shown in FIG. 3 has a pattern 6 on the surface of a flexible base sheet 2 and a crosslinked cured coating 3 of ionizing radiation-curable resin, and the one shown in FIG. In the example shown in FIG. 1, first and second flexible sheets constituting a flexible base sheet 2 are laminated using an adhesive layer 7.

The flexible base sheet 2 having rigidity may be made of polyester, polyethylene, polycarbonate, polystyrene,
Plastics and films such as polyacrylonitrile, ABS, nylon, and polypropylene are selected depending on the usage situation.

Among these, films of polyester, polycarbonate, polyacrylonitrile, or posistyrene are preferred because of their high rigidity.

Alternatively, as the rigid flexible base sheet 2, metal foils such as iron, copper, tin, lead, aluminum, or stainless steel can also be used. Convenient for fixing paper, etc. onto the board with magnets.

The cross-linked cured coating 3 of ionizing radiation-curable resin is a coating film of a composition mainly composed of ionizing radiation-curable resin, in which cross-linking has been introduced by irradiation with ionizing radiation.

Ionizing radiation-curable resins include unsaturated polyester,
Those having an acrylic group such as polyether acrylate, polyester acrylate, epoxy acrylate, urethane acrylic V-), spiroacetal acrylate, polybutadiene resin, polythiol polyene resin, etc. can be used.

The above ionizing radiation curable resins can be used alone, but in order to improve the curability and hardness of the cured coating, it is recommended to add a polyfunctional additive such as trimethylolpropane triacrylate, pentaerythritol triacrylate, or trifunctional monomers such as dipentaerythritol hexaacrylate, neopentyl glycol diacrylate, triprobin glycol diacrylate, diethylene glycol diacrylate, or 1,6-
Bifunctional monomers such as hexanediol diacrylate,
Alternatively, it can be used by appropriately selecting from monomers such as tetrafunctional, pentafunctional, or hexafunctional monomers.

In addition, various additives can be added to the ionizing radiation-curable resin, but when using ultraviolet rays during curing, photoinitiators,
For example, acetophenones, benzophenone, Michler's ketone, benzoin, benzyl methyl ketal, penzoyl benzoate, α-niasiloxime ester, tetramethylthiuram monosulfide, or thioxanthone, or as an ultraviolet sensitizer, n-butylamine, Triethylamine, trilobylphosphine, etc. can be added.

It is desirable that a composition mainly composed of an ionizing radiation-curable resin contains a matting agent in order to adjust the gloss of the cured coating film. As the matting agent, inorganic particles such as limescale, calcium carbonate, and precipitated barium carbonate, or organic particles such as fluorine particles and polyethylene particles can be used. Among these matting agents, it is preferable to use organic particles such as fluorine particles from the viewpoint of erasing written content and improving wear resistance.

Compositions based on ionizing radiation-curable resins can be coated using conventional coating methods such as blade coating, gravure coating, coating, knife coating, reverse roll coach ink, kiss coating,
It is applied to the surface of the flexible base sheet 2 by a method such as spray coating or offset gravure coating.

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

The electron beam is emitted from various electron beam accelerators such as Co, Croft-Walton type, Bumpgraph type, resonant transformer type, insulated core transformer type, linear type, Dynamidron type, and high frequency type, and has an energy of 50 to 1000 Kev, Good tl, < is 100~
An electron beam with an energy in the 300 KeV (D range) is used, and ultra-high pressure mercury lamps, high pressure mercury lamps,
Ultraviolet light emitted from a light source such as a low-pressure mercury lamp, carbon arc, xenon arc, or metal halide lamp is used.

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

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, -, Mi, -211 The whiteboard sheet of the present invention has the basic structure as described above, but it can take various forms as illustrated in FIGS. 2 to 4. It is.

In the flexible base sheet shown in FIG. 2, first and second flexible sheets are laminated, and the first flexible sheet 4 has rigidity and heat resistance. The second flexible sheet 5 has an upper layer of a crosslinked cured coating of ionizing radiation curable resin that has excellent adhesion. The material of the first flexible sheet 4 is basically the same as the material of the rigid flexible base sheet 2. Also, the second
The material of the flexible sheet 5 is selected depending on the material constituting the cross-linked cured film of the ionizing radiation-curable resin in the upper layer, but in most cases, a film mainly made of polyvinyl chloride resin or a Preferably, sheets are used.

Films or sheets mainly made of polyvinyl chloride resin are made of polyvinyl chloride resin and, if necessary, a plasticizer, etc. When adding a plasticizer, the amount of plasticizer added is 30 parts by weight or less per 100 parts by weight of polyvinyl chloride resin. The amount is preferably 10 parts by weight or less from the viewpoint of heat resistance and rigidity. Furthermore, it is also possible to use a resin modifier such as ABS resin in order to impart further heat resistance and rigidity.

What is the thickness of the first and second flexible sheets?

The first flexible sheet has a thickness of 25 to 200 μm, preferably 2
5-10 Q tt*, second flexible sheet 30-5
00 μm, preferably 50 to 200 μm (71). Therefore, the thickness of the flexible base sheet 2 is 55 to 700 Ilr.
n1 preferably 100-350μ! It is.

The first and second flexible sheets may be laminated by laminating them together by an appropriate method, for example.

If you use a dry lamination method using a solvent-based vinyl, acrylic, polyamide, evoquin, rubber, or polyurethane adhesive as the adhesive, it will become a target for the writing position.

It is preferable that it has a frame like a monthly calendar and can indicate where to write the date and day of the week.

The ink used for printing is prepared by kneading a vehicle with a pigment or dye colorant, a plasticizer, a stabilizer, other additives, a solvent or a diluent, and examples of the vehicle include ethylcellulose, ethylhydrokine, ethylcellulose, etc. , cellulose acetate propionate,
Cellulose derivatives such as cellulose acetate, polystyrene,
Styrene resins such as poly-α-methylstyrene and styrene copolymer resins, acrylic or methacrylic resins alone or copolymer resins such as polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, polybutyl acrylate, rosin, rosin One or more of modified maleic acid resin, rosin modified phenol resin, rosin ester resin such as polymerized rosin, polyvinyl acetate resin, coumaron resin, vinyl toluene resin, vinyl chloride resin, polyester resin, polyurethane resin, butyral resin, etc. In order to selectively use and print a pattern using the above inks, gravure printing, offset gravure printing, silk screen printing, offset printing, etc. can be used.

It is also effective to subject the whiteboard sheet of the present invention to antistatic treatment. In particular, the whiteboard sheet of the present invention tends to accumulate electric charge because it is transported when copying, so it is recommended that either the front or back side of the whiteboard sheet or both surfaces be antistatically treated. , especially on the back side (in the case of FIG. 1, the flexible base sheet 2
It is preferable to apply antistatic treatment to the lower surface side (the lower surface side of the first flexible sheet 4 in FIGS. 2 to 4).

Antistatic treatment can be achieved in a variety of ways, for example by coating with an antistatic agent.

This may be done by kneading it into the sheet or the like.

Cationic and anionic antistatic agents.

Various nonionic and amphoteric surfactants, inorganic substances such as metal powder, carbon powder, or graphite, or a polypropylene coating agent can be used.

(Effects of the Invention) Since the whiteboard sheet of the present invention has the above-mentioned structure, it has the same surface performance as a conventional whiteboard, but is flexible and can be easily transported by roll etc. Because it is rigid, there is no problem in transporting or handling it, and since the surface has a cross-linked cured coating of ionizing radiation-curable resin, the surface has excellent abrasion resistance and the erasability of written content. It is.

(Example) Using polyvinyl chloride ink (manufactured by Showa Ink Kogyo Co., Ltd., orange color) on the surface of a 100μ thick white polyvinyl chloride film (manufactured by Riken Vinyl, plasticizer 5 PHIt), 50 μm was printed by gravure printing. A grid consisting of vertical and horizontal lines with layer spacing was printed.

Next, a urethane acrylate ultraviolet curable resin paint (manufactured by Dainichiseika, Ltd., manufactured by Dainichiseika Co., Ltd., printed on the printed surface of a white polyvinyl chloride film with Teflon howder added to make it matte and improve abrasion resistance) was applied to the printed surface of the white polyvinyl chloride film.・Place a 100μ thick polyester film (Lumirror 100μ, manufactured by Toshi) on the back side of the coated film with polyurethane adhesive (Manufactured by Narita Pharmaceutical Co., Ltd., Takera, Ri A-375/Takene) A
-3), and then gravure coated the non-laminated surface of the polyester film with antistatic ink (manufactured by Showa Ink Kogyosho).

The whiteboard sheet obtained as described above had excellent writability and erasability with a water-based pen, and the sheet as a whole had sufficient heat resistance and rigidity, and there were no problems due to charging.

[Brief explanation of drawings]

1 to 4 are sectional views showing embodiments of the present invention.

Claims (6)

[Claims] (1) A whiteboard sheet having a cross-linked cured coating of an ionizing radiation-curable resin on the surface of a rigid, flexible base sheet. (2) The whiteboard sheet according to claim (1), wherein the flexible base sheet is heat resistant. (3) The flexible base sheet is a laminate of a first flexible sheet having rigidity and heat resistance and a second flexible sheet with excellent adhesion of a crosslinked cured coating of ionizing radiation curable resin. and has a cross-linked cured coating of an ionizing radiation-curable resin on the surface of the second flexible sheet.
) whiteboard sheet. (4) A whiteboard sheet according to any one of claims (1) to (3), wherein the flexible base sheet has a pattern that can be seen through the surface. (5) A whiteboard sheet according to any one of claims (1) to (4), wherein the flexible base sheet is subjected to antistatic treatment. (6) The whiteboard sheet according to claim (5), wherein the first flexible sheet is subjected to antistatic treatment.