CN111491804A - writing board - Google Patents

Abstract

A writing board is provided which is capable of recording high contrast images with little change in contrast over time and which is easy to record and erase. The writing board of the present invention includes a base material and a light-transmitting cover plate, the base material is provided with a coloring layer and an adhesive layer, the light-transmitting cover plate is formed with a matte surface on one surface, and the writing board is made of the adhesive layer. The lamination layer is arranged in such a manner that the matte surface is in contact. The arithmetic mean height Sa of the matte surface is 0.10 to 0.50.

Description

writing board

technical field

The present invention relates to a writing board (sheet) capable of repeated writing and erasing, which can record an image by changing the color density (depth) of a pressurized portion, and which can be easily restored by erasing the image.

Background technique

Conventionally, a writing board is known, which is composed of a base material having an adhesive surface and a transparent cover plate provided on the base material, and by pressing from above the cover plate, the base material and the cover plate in the portion to be pressed are formed. In close contact, an image can be recorded in the close contact part. In addition, writing boards composed of a non-adhesive substrate and a transparent cover with an adhesive surface provided on the substrate are also known. With such a writing board, the image can be erased by peeling off the base material and the cover plate, and the original state can be restored. Therefore, writing and erasing can be repeated.

Such writing boards can be applied to recording boards, displays in stores, educational toys, educational materials, and the like, and various products are being researched and developed. For example, Patent Documents 1 to 2 disclose sheets and teaching toys that can be described repeatedly.

prior art literature

Patent Document 1: Japanese Patent Laid-Open No. 2010-042618

Patent Document 2: Japanese Patent Laid-Open No. 2001-142387

SUMMARY OF THE INVENTION

However, according to the research of the present inventors, these writing boards have problems such as low contrast of recorded images, deterioration of contrast of recorded images over time, too high adhesiveness and difficulty in peeling off, and damage to the substrate or cover during peeling, etc. The problem needs to be further improved.

The writing board of the present invention has a base material and a light-transmitting cover plate,

The base material has a colored layer and an adhesive layer,

The light-transmitting cover plate is provided with a film, and a matte surface is formed on one surface of the film,

The writing board is arranged so that the adhesive layer is in contact with the matte surface, and is characterized in that:

The arithmetic mean height Sa of the matte surface is 0.10 to 0.50 μm.

According to the present invention, there is provided a writing board capable of recording high-contrast images, with little change in image contrast over time, and which is easy to record and erase.

Description of drawings

FIG. 1 is a conceptual cross-sectional view of a tablet according to a first embodiment of the present invention.

2 is a conceptual cross-sectional view of a tablet according to a second embodiment of the present invention.

Fig. 3 shows the appearance of the tablet of Example 4-1 before image recording.

Fig. 4 is the appearance after image recording of the tablet of Example 4-1.

Fig. 5 is the appearance of the tablet of Example 4-3 before image recording.

FIG. 6 is the appearance after image recording of the tablet of Example 4-3.

Detailed ways

Hereinafter, embodiments of the present invention will be described in detail.

[Tablet of the first embodiment]

A conceptual cross-sectional view of the tablet according to the first embodiment of the present invention is shown in FIG. 1 . The writing board 100 includes a base material 110 and a cover plate 120 . The base material 110 and the cover plate 120 are arranged so as to face each other. Here, the base material and the cover plate may be bonded or fixed at the ends so as not to be separated from each other, or they may not be bonded to each other but independent. When the base material and the cover plate are not combined with each other, the combination is called a writing board.

In the initial state of the writing board before recording an image, the base material and the cover plate are not in close contact, and an air layer exists at the interface between them.

In the case of recording an image, a desired portion is pressed from the upper part of the cover plate. Just below the pressed portion, the base material is in close contact with the cover plate. As a result, the air layer existing at the interface between the base material and the cover plate disappears substantially, and the refractive index of the interface changes.

As a result, the refractive index is changed at the interface of the unpressurized portion and the interface of the pressurized portion, and a contrast is generated, whereby an image is recorded. Generally, in the pressurized portion, the color of the base material can be observed from the upper part of the cover plate. The method of pressurization is arbitrary, and there may be used a pen made of a resin material or the like to pressurize in a letter shape, or a method of pressing a relief such as a stamp (stamp) to transfer a pattern.

Then, the cover plate is peeled off from the base material, thereby generating an air layer again at the interface, and erasing the image. The method of peeling off the cover plate is arbitrary, the cover plate can be pulled up from the end, or the rod can be inserted and moved between the substrate and the cover plate.

In this way, the writing board of the present invention can repeatedly perform image recording and erasing.

[Substrate]

The substrate used in the present invention includes a colored layer and an adhesive layer. In the first embodiment, the base material includes a colored support 111 having a colored layer, and includes an adhesive layer 113 on the surface opposite to the cover plate. The adhesive layer 113 is a layer that is in close contact with the cover plate during image recording, and the color of the colored support 111 can be observed, for example, from the surface of the writing board by the adhesion.

The adhesive layer 113 is formed on at least one surface of the colored support 111 . If adhesive layers are provided on both sides of the colored support, and two cover sheets facing each side are combined, a writing board capable of recording on both sides can also be produced.

Here, the colored support is not particularly limited, but the colored support needs to be colored in order to maintain a high contrast of the image observed from the surface of the writing board at the time of image recording. In addition, in order to impart physically sufficient strength to the writing board, the colored support is also required to have strength.

From such a viewpoint, as shown in FIG. 1 , in one embodiment, a colored support including a core plate 111b and a colored layer 111a can be used. By using a core board with sufficient physical strength, various coloring layers can be selected according to cost and color. In this case, the core plate preferably has sufficient physical strength, and can be selected from any conventionally known materials. For example, it can be selected from polyolefin resins and polyester resins, and more specifically, (i) the polyolefin resin film can be selected from polyethylene (PE) resins, polypropylene (PP) resins, ethylene-propylene copolymers, (ii) Polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) Choose from ethylene naphthalate resin, polybutylene naphthalate resin, etc. Among them, polyester-based resins are preferred, and PET resins are particularly preferred from the viewpoint of strength and workability. In addition, the colored support 111 may be composed of only the colored layer.

The surfaces of these films can be subjected to conventionally known surface treatments such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and application of a primer (formation of an undercoat layer).

The thickness of the core plate is not particularly limited, but in order to achieve sufficient strength physically, the thickness is preferably 50 to 250 μm.

These core boards can be colorless and transparent, colored and transparent, or opaque. When the core plate is colorless and transparent, it is preferable to laminate the core plate and the colored layer. In any event, the colored support is preferably opaque in its entirety. In addition, opaque in the present invention means that the transmittance is less than 80%, preferably less than 60%, in the entire wavelength region of 400 to 760 nm. On the other hand, colorless and transparent means that the transmittance is 80% or more, preferably 90% or more, in the entire region of the wavelength range. In addition, colored and transparent means that a region with a transmittance of less than 80% exists in a part of the wavelength region.

In order to make the colored support opaque, in the case of using a colored layer, the colored layer can be formed by laminating a colored sheet material or the like with a transparent core plate, or by coating the surface of the transparent core plate with a colored layer formed.

Examples of the colored sheet-like material include colored paper, colored resin films, films made of resin materials in which colored particles are dispersed, colored fiber aggregates, and the like. When forming a colored layer by coating, a composition containing a binder in which colored particles are dispersed can be coated, dried or cured, to form a colored layer. The colored particles include inorganic pigment particles, metal powder, metal oxide powder, and the like.

Furthermore, as the colored support, a colored support provided with a metal plate or a metal layer as a colored layer can also be used. When such a metal surface is used for a colored support, special effects can be obtained. In this case, the contrast of the image obtained by writing is relatively low.

However, if the recorded image is copied using a copier, an image with high contrast is copied. By utilizing such an effect, it is possible to obtain the effect of being able to shine brightly.

It is preferable that the surface smoothness of the cover plate side of a colored support is high. An adhesive layer is provided on this surface as will be described later, but since the final surface of the adhesive layer preferably has high smoothness, it is preferable that the smoothness of the cover plate side surface of the colored support serving as the base is also high. From such a viewpoint, the cover plate side surface of the colored support is preferably a resin-made core plate. Therefore, when the colored support has a structure in which the core plate and the colored layer are stacked, as shown in FIG. 1 , the colored layer is preferably formed on the surface opposite to the surface facing the cover plate.

The base material 110 includes an adhesive layer 113 . Before forming the adhesive layer 113 on the surface of the base material 110, in order to improve the adhesion between the base material and the adhesive layer, an intermediate layer 112 may be provided. When the writing board is in use, since the adhesion and peeling of the adhesive layer and the cover sheet are repeated, the adhesive layer may peel off from the surface of the base material. However, by providing an intermediate layer, such a problem can be improved, and it is also possible to improve the Storage stability of the writing board.

Various resins, such as polyester resin, acrylic resin, urethane resin, acrylic-grafted polyester resin, and silicone resin, are mentioned as a material used for the intermediate layer. The intermediate layer may be formed of polyester resin, for example. Regarding the thickness of the intermediate layer, by increasing the thickness, the adhesion between the substrate and the adhesive layer can be improved, and by reducing the thickness, the color of the colored support can be easily reproduced during image recording. From such a viewpoint, the thickness of the intermediate layer is preferably 0.05 to 1.0 μm.

In the base material used in the present invention, an adhesive layer is formed on the surface of the colored support directly or via an intermediate layer. The adhesive layer is in close contact with the cover plate during image recording, thereby recording an image. Therefore, from the viewpoint of image recording stability, the adhesive force is preferably high, but if it is too high, peeling of the cover sheet during erasing may become difficult, or an unpleasant sound may be generated during peeling, or Damage to the adhesive layer or cover.

In addition, even in the state where the writing board is placed, the cover sheet and the adhesive layer may be brought into close contact, thereby recording an undesired image. Therefore, the adhesive force of the adhesive layer is preferably 1.0 to 5.0 N/m, and more preferably 1.5 to 4.0 N/m. Here, the adhesive force can be measured by performing a 180° peel adhesion force measurement on a test panel as shown in JISZ 0237 method 1.

Such an adhesive layer is usually formed by mixing a catalyst or the like with the adhesive composition as necessary, coating a colored support or a core plate via an intermediate layer as necessary, and heating or the like to make it reaction.

As the material of the adhesive layer, any material can be selected from conventionally known adhesives.

Examples of such adhesives include acrylic adhesives, rubber-based adhesives, polyester-based adhesives, urethane-based adhesives, polyether-based adhesives, silicone-based adhesives, polymer Various adhesives such as amide-based adhesives and fluorine-based adhesives.

Among them, the main component of the silicone-based adhesive is a polymer whose main skeleton is mainly composed of siloxane bonds. Since many silicone-based adhesives exhibit appropriate adhesiveness, and are excellent in chemical resistance, water resistance, and heat resistance, they are preferred. In addition, the silicone-based adhesive is one of the reasons for its small change in adhesive force due to pressure. In addition, the main component of a urethane adhesive is a polymer obtained by condensing an isocyanate compound and a hydroxy compound. Since it is excellent in peelability, it is a preferable adhesive, but the adhesive force is often higher than that of a silicone-based adhesive, and the adhesiveness may need to be adjusted. In addition, when a urethane-based adhesive is used, the adhesive force between the cover sheet and the adhesive layer tends to change depending on the pressure applied during image recording. Therefore, when the uniformity of the force required for peeling of the cover sheet and the uniformity of the contrast of the recorded image are important, a silicone-based adhesive is preferably used.

There are various commercially available adhesives for use in such a method, and a suitable adhesive can be selected from them and used. Specifically, the silicone-based adhesives include LTC755, SD4580PSA, etc. (all are trade names, sold by Toray Dow Corning Co., Ltd.), KR3700, KR3701, KR3704 (all are trade names, sold by Shin-Etsu Chemical Co., Ltd. Co., Ltd.), as a catalyst to be combined therewith, NC-25Catalyst (trade name, sold by Toray Dow Corning Co., Ltd.) and CAT-PL-50T (trade name, sold by Shin-Etsu Chemical Co., Ltd.). In addition, examples of polyurethane-based adhesives include SAIABAIN series SH-101M, SH-101, and SP-205 (all are trade names, sold by Toeヨーケム Co., Ltd.); Polyfunctional isocyanate-based crosslinking agent) (trade name, sold by トーヨーケム Co., Ltd.).

The catalyst combined with the silicone-based binder is preferably a platinum-containing noble metal catalyst because the crosslinking density can be adjusted, and platinum-ruthenium alloy, platinum-palladium alloy, platinum-titanium alloy, etc. are particularly preferably used.

The method of applying the adhesive composition is not particularly limited, and for example, it can be performed using a conventionally known coater such as a gravure roll coater, a die coater, and a bar coater. Alternatively, the adhesive composition may be applied by impregnation, curtain coating, or the like.

After coating, in order to promote the crosslinking reaction and improve the production efficiency, heating is preferably performed. The heating temperature is usually selected from the range of 40 to 150°C, preferably 60 to 130°C.

The thicker the thickness of the adhesive layer, the easier it is to adhere to the cover plate, and the thinner it is, the easier it is to reproduce the color of the colored support at the time of image recording, and the production cost is reduced. Therefore, the thickness of the adhesive layer is preferably 5 to 30 μm, and more preferably 10 to 20 μm. In addition, the surface of the adhesive layer is preferably smooth.

Furthermore, the adhesive layer can be colored. By making the color of the colored support different from the color of the adhesive layer, an image can be recorded using a color synthesized from the color of the adhesive layer and the color of the colored support. In addition, by making the color of the colored support the same as the color of the adhesive layer, an image can be recorded with a higher color density by combining the color density of the adhesive layer and the color density of the colored support. In addition, the adhesive layer can also function as a colored layer. That is, the step of separately providing a colored layer can be omitted by giving a high-density color to the adhesive layer.

[cover]

The cover plate 120 used in the present invention needs to be able to observe the color of the base material from the surface of the writing board when it is in close contact with the adhesive layer 113 . Therefore, it is necessary to use a light-transmitting cover plate as a cover plate. Here, the light-transmitting cover plate refers to a cover plate capable of recognizing the color or pattern of the colored support layer located therebelow from the upper surface. In general, it is preferable that the cover plate be colorless and transparent. Since the cover plate has high transmittance in the entire wavelength range of 400 to 760 nm, it is possible to perform image recording faithful to the coloration applied to the substrate. However, it is also possible to colour the cover. If a cover film having transparency in a part of the wavelength range of 400 to 760 nm is used, an image can be recorded in a color different from the color applied to the base material. In addition, a characteristic color expression may be realized by including a metallic pigment in the cover plate (details will be described later).

Such cover sheets are usually provided with a transparent film. Since the cover sheet requires not only transparency but also physical strength, it is preferable to use a film formed of the material exemplified in the above-mentioned colored support. When coloring a cover plate, a coloring layer may be laminated|stacked on such a transparent film. In addition, the colored layer in this case is independent from the colored layer contained in the colored support.

In the present invention, a matte surface (matte surface, matte surface) is formed on the adhesive layer side surface of the cover plate. The properties of the writing board can vary widely depending on the surface shape of the matte surface.

In the writing board of the present invention, if the arithmetic mean height Sa of the matte surface is large, a matte color tone is likely to be expressed, and even if the writing board is left, the adhesion between the cover plate and the adhesive layer seldom occurs. If it is small, there is a tendency that an image with high contrast can be formed. From such a viewpoint, in the present invention, the arithmetic mean height Sa of the matte surface is 0.10 to 0.50 μm, preferably 0.15 to 0.30 μm.

In addition, the arithmetic mean height Sa can be measured with a three-dimensional roughness meter. Specifically, in these measurements, a laser microscope LEXT-OLS4100 (trade name, manufactured by Olympus Corporation) can be used.

In addition, the unevenness on the matte surface can prevent the adhesive layer and the cover sheet from adhering in the state before the image is recorded, and can properly maintain the adhesion between the adhesive layer and the cover sheet during image recording. Easy to peel off when erasing images. In order to form such a matte surface, the haze value is preferably 70 to 95%. The haze value can be measured with a turbidity meter TC-HIII (trade name, manufactured by Tokyo Denshoku Co., Ltd.).

The method of forming the matte surface 121 on the surface of the cover plate 120 is not particularly limited, and examples include a method of directly etching the surface of a film that is the main structure of the cover plate, a method of laminating a film having irregularities, and a method of dispersing the A method in which a resin composition with fine particles is applied on the surface of a film and dried or cured to form a concavo-convex surface. A composition containing a compound that generates bubbles by heating or the like is applied on the surface of the film, and the composition layer is formed by heating or the like. A method of generating air bubbles to form irregularities on the surface, etc. Moreover, as a cover film, the cover plate which formed the matte surface on the surface can also be obtained by shaping|molding the resin composition which disperse|distributed the microparticles|fine-particles into a film shape.

Among them, a resin composition in which fine particles are dispersed is preferably used because it is easy to control the roughness of the matte surface. In particular, from the viewpoints of quality stability and properties of the cover film, a method of applying a resin composition in which highly transparent fine particles such as silica are dispersed on the surface of the film, and heating to cure the resin is preferably employed. Microparticles can be organic materials or inorganic materials. Examples of the organic material used for the fine particles include acrylic resins such as polymethyl methacrylate, polystyrene, styrene-acrylic resins, polycarbonate resins, urethane resins, epoxy resins, polyester resins, and polyesters. Polyurethane resin, etc. Moreover, as an inorganic material used for microparticles|fine-particles, a silica (silica), titanium dioxide, barium sulfate, calcium carbonate, talc, mica, a metal flake, a metal oxide flake, etc. are mentioned, for example. Among them, when mica, metal flakes, or metal oxide flakes are used, the color produced during image recording becomes metallic, and it has the characteristic of recording beautiful images (details will be described later). In addition, in this case, by making the colored layer a color with a high density, typically black, the contrast can be increased and the metallic color can be more beautifully observed, which is preferable.

The average particle diameter of these fine particles is preferably 0.05 to 5.0 μm. Here, the average particle diameter is measured on a volume basis using a laser diffraction method (principle), and can be measured by, for example, MICROTRAC9320-X100 (manufactured by Honeywell).

Moreover, as resin used as a binder of a composition, vinyl chloride vinyl acetate copolymer resin, epoxy resin, acrylic resin, polyester resin, urethane resin, melamine resin, etc. are mentioned. Among them, acrylic melamine resins, polyester melamine resins, acrylic urethane resins and the like are preferably used in view of their excellent physical strength and optical properties.

Moreover, toluene, methyl ethyl ketone, etc. are mentioned as a solvent which melt|dissolves or disperse|distributes these.

FIG. 1 illustrates a structure in which a matte coating layer 121a having a matte surface 121 is laminated on the surface of a film 122 by either method.

In addition, there are physical methods and chemical methods for directly etching the film surface.

Among them, the physical method is preferable because the steps are relatively simple and finer unevenness can be formed. As a method of physically etching the surface of the film, a sandblasting method and a scratching method are mentioned.

In this invention, it is preferable that the hardness of the matte surface of a cover plate is high. Specifically, the pencil hardness (JIS K5600-5-4) is preferably F or more, and more preferably H or more. According to the study of the present inventors, when an image is recorded on a writing board and then erased, a trace of the image may remain on the cover plate. As a result, the contrast of the recorded image formed later will be lowered. However, in the present invention, by appropriately setting the hardness of the matte surface, such a problem can be improved and such a decrease in contrast can be suppressed. In addition, the adhesiveness between the cover plate and the adhesive layer can be appropriately adjusted, and image recording and erasing can be easily performed.

The surface of the cover plate opposite to the surface on which the matte surface is formed is subjected to pressure and stress during image recording. In the case of pressing by a stamp or the like, a force in a vertical direction is applied to the surface of the tablet. On the other hand, in the case of recording an image with a pen, for example, a vertical force is applied in order to make the cover and the adhesive surface close to each other, but at the same time, frictional force is generated between the surface of the cover and the tip of the pen. . As a result, the surface of the cover plate may be damaged and the contrast of the recorded image may be lowered. In order to prevent such a problem, it is preferable that the cover plate used by this invention is provided with the surface protection layer 123 on the surface opposite to the surface on which the matte surface is formed.

Such a surface protective layer can be formed by laminating a surface protective film on the surface of a film constituting a cover plate, or applying and curing a composition containing a resin material, or the like. In particular, since various surface protection films are commercially available, it is convenient to use a surface protection film according to the purpose from them. Examples of such a protective film include a protective film that protects the surface with high hardness, a protective film that reduces the frictional force on the surface to prevent scratches, has an appropriate elasticity to relieve physical impact, or is physically damaged once Self-healing protective film, etc. The surface protective film having high hardness is, for example, a film formed of a hard plastic, and the specific hardness is preferably HB or more in terms of pencil hardness. Moreover, as a film with low frictional force, the film which consists of a high molecular weight polyethylene with a smooth surface is mentioned, for example, Specifically, it is preferable that the friction coefficient of the surface is 0.15 or less. In addition, the film which relieves physical impact or self-repairs is a film which has a flexible structure and is made of a polymer material such as silicone resin. In this invention, it is preferable to use the surface protective film which has these several characteristics as a protective film. As such a film, for example, a high-toughness self-healing coating film SR-TEBF (trade name, manufactured by Toray Film Processing Co., Ltd.), and Tokro HC film hard coat product HC1000 (manufactured by Toyo Cross Co., Ltd.) are commercially available. and other films.

In order to achieve sufficient light transmittance, preferably high transparency, and to transmit the pressure during image recording to the interface between the cover plate and the adhesive layer, the thickness of the cover plate is preferably thin, and in order to improve physical strength, the cover plate is preferably thickness is thicker. From such a viewpoint, the thickness of the main film constituting the cover plate is preferably 38 to 100 μm, and more preferably 50 to 75 μm. In addition, in the case of providing a matte coating, in order to obtain the target surface roughness, the matte coating is preferably thickened, and in order to maintain the transparency of the cover plate, the matte coating is preferably thinned. From such a viewpoint, the thickness of the matte coating layer is preferably 2 to 20 μm, and more preferably 5 to 10 μm. Moreover, when providing a surface protective layer, it is preferable that the thickness of the surface protective layer is 0-100 micrometers, and it is more preferable that it is 25-50 micrometers.

[Tablet of Second Embodiment]

A conceptual cross-sectional view of the tablet according to the second embodiment of the present invention is shown in FIG. 2 . The writing board 200 includes a base material 210 and a cover plate 220 . The base material 210 has a structure different from that of the first embodiment.

The base material used for the writing board of the second embodiment of the present invention includes a core plate 211 and a colored adhesive layer 213 on the surface facing the cover plate. This colored adhesive layer is formed by integrating the colored layer and the adhesive layer of the present invention, and has both the functions of the colored layer and the adhesive layer of the first embodiment. The colored adhesive layer 213 is a layer that is in close contact with the cover plate during image recording, and the color of the colored adhesive layer 213 can be observed, for example, from the surface of the writing board by the adhesion. The colored adhesive layer 213 is formed on at least one surface of the core board 211 . If colored adhesive layers are provided on both sides of the core board, and two cover sheets facing each side are combined, a writing board capable of recording on both sides can also be formed.

The tablet of the second embodiment can have the same configuration as that of the tablet of the first embodiment except for the base material.

As the material used for the colored adhesive layer, the same materials as those used for the colored layer or the adhesive layer in the first embodiment can be used.

[metal layer]

The writing board of the present invention may be provided with a metal layer. The metal layer can be placed in various positions on the writing board. A metal layer may be newly added to the structure of the above-mentioned tablet, and any layer may also function as a metal layer.

For example, a new metal layer can be inserted between the core board and the adhesive layer, or the colored layer can be made a metal layer, or the adhesive layer can be made to contain a metallic pigment so that the adhesive layer can function as a metal layer, or the surface can be protected The layer contains metallic pigments so that the surface protective layer functions as a metallic layer. Additionally, as mentioned above, metallic pigments can also be added to the cover sheet or matte coating. Among these, it is preferable to contain a metallic pigment in an adhesive layer or a surface protective layer. According to such a configuration, the recorded image can be expressed more beautifully. In such a case, it is preferable to arrange a layer with a higher color density on the lower side than the metal layer. Specifically, when the surface protective layer is used as a metal layer, it is preferable to increase the color density of the adhesive layer or the support, and when the adhesive layer is used as a metal layer, it is preferable to increase the color density of the support. In this way, by arranging a layer with a high color density, such as a black layer, below the metal layer, a metal image can be expressed more beautifully.

The metallic pigment contained in the metallic layer is not particularly limited. Examples of such pigments include synthetic mica, natural mica, metal powders, metal flakes, metal oxide powders, metal oxide flakes, and the like. In particular, the transparent flat metallic luster pigment obtained by coating the surface of the transparent core material with a metal oxide is useful. As the transparent flat metallic luster pigment, a transparent metallic luster pigment obtained by coating the surface of a core material such as natural mica, synthetic mica, flat glass flakes, and flaky alumina with a metal oxide can be used. These metallic luster pigments preferably have an average thickness of 0.1 to 5 μm and an average particle size of 2 to 200 μm, more preferably 2 to 100 μm, in order to achieve a high aesthetic effect and maintain the smoothness of the metal layer surface.

Such a transparent flat metallic luster pigment can express a very beautiful image by combining with the hue of a coloring base material.

There are various commercially available products of such metallic pigments, and they can also be used. Examples of the metal pigments that can be used in the present invention include the "Iridin" series manufactured by Melk Corporation, which coats the surface of natural mica with metal oxides such as titanium oxide, and Nippon Koken, which coats the surface of synthetic mica with metal oxides. Trade names of "Aruta Mika" and "ツインクルパール" series manufactured by Kogyo Co., Ltd., trade name of Nippon Sheet Glass Co., Ltd. in which scaly glass flakes are coated with titanium oxide, and "Mishin" series manufactured by Nippon Sheet Glass Co., Ltd., and flaky alumina coated with metal oxide. The brand name "Silric" series manufactured by Melk Corporation on the surface, etc.

[Configuration example of a writing board]

As a typical structural example of the writing board of this invention, the following example is mentioned.

(i) a writing board, characterized in that it is provided with a base material and a transparent cover plate, the base material is provided with a colored support and an adhesive layer formed on the surface of the colored support, and the transparent cover plate is provided with a film, in which A matte surface is formed on one surface of the film, the writing board is arranged so that the adhesive layer is in contact with the matte surface, and the arithmetic mean height Sa of the matte surface is 0.10 to 0.50 μm.

(ii) A writing board comprising a base material including a core sheet and a colored adhesive layer formed on a surface of the core sheet, and a transparent cover sheet, wherein the transparent cover sheet includes a film, wherein the A matte surface is formed on one surface of the film, and the writing board is arranged so that the colored adhesive layer is in contact with the matte surface.

(iii) A writing board, characterized in that it is provided with a base material and a transparent cover plate, the base material is provided with a colored support and an adhesive layer formed on the surface of the colored support, and the transparent cover plate is provided with a film, in which A matte surface is formed on one surface of the film, the tablet is arranged so that the adhesive layer is in contact with the matte surface, and the matte surface has a hardness of F or more of a pencil hardness.

(iv) A writing board comprising a colored base material including a support and an adhesive layer formed on the surface of the support, and a cover sheet, wherein the cover sheet includes a film, and the film is provided on the film. A matte surface is formed on one surface of the writing board, the writing board is arranged so that the adhesive layer is in contact with the matte surface, and the colored base material or the cover plate is provided with a metal layer containing a metallic pigment.

Hereinafter, the present invention will be described with reference to each example.

[Example 1-1]

90 parts of silicone-based adhesive (LTC 755Coating (trade name), Toray Dow Corning Co., Ltd.), 10 parts of silicone-based adhesive (SD 4580PSA (trade name), Toray Dow Corning Co., Ltd.), 0.7 parts of platinum A catalyst (NC-25 (trade name), Toray Dow Corning Co., Ltd.) was dissolved in toluene, and the solution was thoroughly stirred, then applied to a polyester film (core plate) with a thickness of 50 μm using a coater, and cured at 120°C In 2 minutes, a transparent adhesive layer with a thickness of 15 μm was formed on the film surface. Furthermore, black paper was laminated on the opposite side of the adhesive layer to obtain a base material.

Moreover, the coating liquid containing polyester melamine resin and silica fine particle was apply|coated to the back surface of the polyester film of thickness 50 micrometers, and the cover sheet 1 which formed the matte surface on the surface was obtained. The Sa of this sheet was 0.15 μm, the haze value was 72.8, and the pencil hardness was H.

This base material was combined with a cover sheet to make a writing board.

[Examples 1-2 to 1-7 and Comparative Examples 1-1 to 1-2]

With respect to Example 1-1, the raw material of the adhesive layer and the method of forming the matte surface of the cover plate were changed to prepare writing boards of Examples 1-2 to 1-7 and Comparative Examples 1-1 to 1-2. The raw materials of the adhesive layer are shown in Table 1. In addition, the cover plates 2-6 are manufactured as follows.

Cover sheet 2: A cover sheet 2 having a matte surface formed on the surface was obtained by applying a coating liquid containing a polyacrylic melamine resin and silica fine particles to the back surface of a polyester film having a thickness of 50 μm. The Sa of this sheet was 0.24 μm, the haze value was 80.0, and the pencil hardness was F.

Cover plate 3: The cover plate 3 was obtained by changing the type and compounding amount of the polyester melamine resin and the silica fine particles with respect to the cover plate 1. The Sa of this sheet was 0.29 μm, the haze value was 77.0, and the pencil hardness was H.

Cover plate 4: A cover plate 4 was obtained by sandblasting the surface of a polyester sheet having a thickness of 50 μm to form a matte surface. The Sa of this sheet was 0.11 μm, the haze value was 76.2, and the pencil hardness was 6B.

Cover plate 5: The cover plate 5 was obtained by changing the type and compounding amount of the polyacrylic melamine resin and the silica fine particles with respect to the cover plate 2. The Sa of this sheet was 0.07 μm, the haze value was 60.0, and the pencil hardness was H.

Cover plate 6 : A light-diffusing polyethylene terephthalate sheet (light up LDE 50 μm (trade name), manufactured by Kyoto Co., Ltd.) was used as the cover plate 6 . The Sa of this sheet was 0.95 μm, the haze value was 91.0, and the pencil hardness was 6B.

[Evaluation]

preservation over time

After assembling the writing board, it was left to stand, and the state change was visually evaluated.

A: There is no adhesion between the adhesive layer and the matte coating, which is good.

B: The adhesive layer and the matte coating adhered over time.

C: The adhesive layer is attached to the matte coating.

writing performance

The recorded image when writing with the pen tip of the fiber bundle was visually evaluated.

A: A good recorded image can be obtained.

B: Although a recorded image was obtained, the contrast was low.

C: No recorded image was left even when writing was performed, or the recorded image disappeared naturally immediately after writing.

Erase performance

After recording, the matte coating layer and the adhesive layer were peeled off, and the ease of peeling when erasing the recorded image was evaluated.

A: The recorded image can be easily and cleanly erased with a slight force.

B: The image cannot be erased without a large peeling force. Or produce a loud peeling sound.

C: The cover plate or the adhesive layer was damaged during erasing.

record performance

After the image was recorded, the recorded image after 1 day was visually evaluated.

A: No change in the recorded image was observed.

B: The image becomes less clear than immediately after recording.

C: The recorded image cannot be visually confirmed (image disappears).

[Example 2-1]

It will contain 80 parts of silicone-based adhesive (LTC 755Coating (trade name), Toray Dow Corning Co., Ltd.), 20 parts of silicone-based adhesive (SD 4580PSA (trade name), Toray Dow Corning Co., Ltd.), 0.7 part A platinum catalyst (NC-25 (trade name), Toray Dow Corning Co., Ltd.) and 3 parts of a toluene solution of a black colorant (CP-96BLACK (trade name) Toray Dow Corning) were thoroughly stirred, and then applied to a thickness of The polyester film (core plate) of 50 μm was cured at 120° C. for 2 minutes to form a black colored adhesive layer with a thickness of 15 μm on the film surface. Furthermore, black paper was laminated on the opposite side of the adhesive layer to obtain a base material.

Moreover, the coating liquid containing a polyacrylic acid melamine resin and silica fine particles was apply|coated to the back surface of the polyester film of thickness 50 micrometers, and the cover plate which formed the matte surface on the surface was obtained.

This base material was combined with a cover sheet to make a writing board.

[Examples 2-2 to 2-5 and Comparative Examples 2-1 to 2-2]

Compared with Example 2-1, the raw materials of the adhesive, the method of forming the matte surface of the cover plate, and the color of the base material were changed to prepare Examples 2-2 to 2-5 and Comparative Examples 2-1 to 2-2. writing pad.

[Evaluation]

Record image contrast

The sharpness of the recorded image when writing with the pen tip of the fiber bundle was visually evaluated.

A: A sharp recorded image is formed.

B: The recorded image is unclear, or the recorded image cannot be visually confirmed.

Record image density

The recorded image when writing with the pen tip of the fiber bundle was visually evaluated.

A: A very dark recorded image was visually confirmed.

B: A dark recorded image was visually confirmed.

C: A faint recorded image was visually confirmed.

D: The recorded image was so faint that it could not be visually confirmed.

Record image chromatic aberration

The color difference ΔE ₀₀ was measured based on the CIE2000 color difference method using a fluorescence spectrophotometer FD-7 (trade name, manufactured by Konica Minolta Co., Ltd.).

Table 2

1: Acrylic melamine resin coating product containing _SiO2 particles Haze value: 80.0 pencil hardness F

2: Polyester melamine resin coated product containing _SiO2 particles Haze value: 72.8 Pencil hardness: H

3: Sandblasted PET haze value: 76.2 pencil hardness 6B

[Example 3-1]

100 parts of a silicone-based binder (KR3704 (trade name), Shin-Etsu Chemical Co., Ltd.) and 1.5 parts of a platinum catalyst (CAT-CL-50T (trade name), Shin-Etsu Chemical Co., Ltd.) were dissolved in toluene, and the mixture was dissolved in toluene. After the solution was sufficiently stirred, it was applied to a polyester film (core board) with a thickness of 50 μm using an applicator, and cured at 120° C. for 2 minutes to form a transparent adhesive layer with a thickness of 15 μm on the film surface. The adhesive force of this adhesive layer was 1.37 N/m.

Furthermore, black paper was laminated on the opposite side of the adhesive layer to obtain a base material.

Moreover, the coating liquid containing polyester melamine resin and silica fine particle was apply|coated to the back surface of the polyester film of thickness 50 micrometers, and the cover plate which formed the matte surface on the surface was obtained.

This base material was combined with a cover sheet to make a writing board.

[Examples 3-2 to 3-3 and Comparative Examples 3-1 to 3-3]

With respect to Example 3-1, the kind of resin for forming the matte surface and the curing conditions were changed, and samples having different hardnesses of the matte surface were produced.

initial contrast

Write on the cover film with a rubber nib, measure the brightness L ^* of the unrecorded part and the recorded part with a spectrophotometer CM3600d (trade name, manufactured by Konica Minolta Co., Ltd.), and set the difference ΔL ^* ₀ as the difference ΔL*0. Initial contrast.

Contrast after 50 trials

After the initial contrast was measured, erasing and writing were repeated 50 times. The brightness L ^* of the unrecorded portion and the recorded portion after the 50th writing was measured, and the difference ΔL ^* ₅₀ was defined as the contrast after the 50th test.

Contrast change

The difference between the initial contrast _ΔL ^* ₀ and the contrast difference L ^* ₅₀ after ₅₀ repetitions was ^defined as the contrast change ^.

[Example 4-1]

It will contain 80 parts of silicone-based adhesive (LTC 755Coating (trade name), Toray Dow Corning), 20 parts of silicone-based adhesive (SD 4580PSA (trade name), Toray Dow Corning), 0.7 part of platinum catalyst (NC -25 (trade name), Toray Dow Corning), 3 parts of black colorant (CP-96BLACK (trade name) Toray Dow Corning) in toluene solution after stirring well, apply it to a polyester film with a thickness of 50 μm using an applicator (core board), it hardened at 120 degreeC for 2 minutes, and formed the adhesive layer colored black with a thickness of 15 micrometers on the film surface. Furthermore, black paper was laminated|stacked on the opposite side of an adhesive layer, and the colored base material was obtained.

In addition, a coating liquid containing a polyacrylic acid melamine resin and silica fine particles was applied to the back surface of a polyester film having a thickness of 50 μm to form a matte surface on the surface. Next, 6 parts of a metallic pigment obtained by coating the surface of synthetic mica with titanium oxide (ツインクルパール BXB (trade name) Nippon Koken Kogyo Co., Ltd., pearl blue) was added to 100 parts of vinyl chloroacetate modified resin (ソルバインC (trade name), Nissin Chemical Industry Co., Ltd.), and 40 parts of an isocyanate-based curing agent (Taito D110N (trade name), Mitsui Chemicals Co., Ltd.) medium, a pearlescent ink was prepared. The ink was applied on the surface opposite to the matte surface of the film, and after drying, a cover plate provided with a metal layer having a thickness of 10 μm was obtained. The Sa of this sheet was 0.24 μm, the haze value was 80.0, and the pencil hardness was F.

This colored base material was combined with a cover sheet to prepare a writing board.

[Example 4-2]

A writing board was produced in the same manner as in Example 4-1, except that the black color paste was removed from the raw material of the adhesive.

[Example 4-3]

With respect to Example 1, except that the black color paste in the raw material of the binder was changed to 6 parts of metallic pigment (Double Pearl BXB (trade name)), and the cover plate was not provided with a metal layer, a writing was prepared in the same manner. plate.

[Evaluation]

An image was recorded by pressing a rubber stamp on a tablet, and the formed image was evaluated visually.

In addition, about the tablet of Examples 4-1 and 4-3, the photographs before and after image recording are shown in FIGS. 3-6.

Exterior

A: An image with a vivid metallic appearance is recorded.

B: An image of the appearance of metal is recorded.

C: Although the image of the metallic appearance is recorded, the minute metallic appearance is also seen in the parts other than the recorded part.

Contrast

A: Very good contrast was obtained.

B: Good contrast was obtained.

C: Sufficient contrast was obtained.

Table 4

Description of reference numerals

100 writing pads

110 Substrates

111 Shading Supports

111a Coloring layer

111b core board

112 Intermediate layer

113 Adhesive layer

120 Cover

121 Matte

121a matte coating

122 Film substrate

123 Surface protection layer

200 writing pads

210 Substrate

211 Support

211 core board

212 Intermediate layer

213 Pigmented Adhesive Layer

220 Cover

221 Matte

221a Matte Coating

222 Film

223 Surface protection layer

Claims (12)

1. A writing board is characterized in that the writing board is provided with a base material and a light-transmitting cover plate,

the base material is provided with a coloring layer and an adhesive layer,

the light-transmitting cover plate is provided with a film, a dull surface is formed on one side surface of the film,

the writing board is disposed such that the adhesive layer is in contact with the matte surface,

the arithmetic average height Sa of the mat surface is 0.10 to 0.50 μm.

2. The writing tablet of claim 1 wherein said writing surface is a surface,

the base material comprises a colored support composed of a core sheet and the colored layer, and an adhesive layer formed on the surface of the colored support.

3. The writing tablet of claim 1 wherein said writing surface is a surface,

the colored layer and the adhesive layer are integrated to form a colored adhesive layer,

the base material is provided with a core board and the colored adhesive layer formed on the surface of the core board.

4. A tablet according to any one of claims 1 to 3,

the hardness of the dull surface is greater than or equal to pencil hardness F.

5. The tablet according to any one of claims 1 to 4,

the matte surface is a surface of a fine particle-containing layer disposed on the surface of the film.

6. The tablet of claim 5 wherein the tablet is a single tablet,

the matte side contains microparticles and a binder selected from the group consisting of vinyl chloride-vinyl acetate copolymer resin, epoxy resin, acrylic resin, polyester resin, polyurethane resin, and melamine resin.

7. A tablet according to any one of claims 1 to 6,

the adhesive layer contains a silicone adhesive.

8. A tablet according to any one of claims 1 to 7,

the adhesive force of the adhesive layer is 1.0-5.0N/m.

9. A tablet according to any one of claims 1 to 8,

the light-transmitting cover plate is provided with the film and a matte coating layer formed on the surface of the film.

10. The tablet of any one of claims 1 to 9,

the light-transmitting cover plate further includes a surface protective layer on a surface opposite to the surface on which the mat surface is formed.

11. The tablet of any one of claims 1 to 10,

the light-transmitting cover plate is transparent.

12. The tablet of any one of claims 1 to 10,

the substrate or the light-transmitting cover plate is provided with a metal layer containing a metal pigment.

Images