JP2019116040A - Writing sheet - Google Patents

Abstract

To provide a writing sheet which allows an image with high contrast to be recorded thereon, can suppress occurrence of contrast change of the image with time and facilitates recording and elimination of the image.SOLUTION: The writing sheet according to the invention comprises a base material comprised of a colored support body and an adhesion layer formed on a surface on the body and a transparent cover sheet having a mat surface formed on one-side surface thereof, where the adhesion layer and the mat surface are arranged to contact each other. An arithmetic mean height Sa of the mat surface is in a range of 0.10-0.50.SELECTED DRAWING: Figure 1

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a writing sheet capable of repetitive writing and erasing, capable of recording an image by changing the color density of a pressurized portion, and further capable of easily erasing and restoring the image.

  Conventionally, a base material having a sticky surface, and a transparent cover sheet provided thereon, the base material and the cover sheet of a portion pressed by pressing from above the cover sheet There is known a writing sheet which is in close contact and can record an image on the close contact portion. Also known is a writing sheet comprised of a non-tacky substrate and a transparent cover sheet having a tacky surface provided thereon. Such a writing sheet can be restored to its initial state by erasing the image by peeling off the base material and the cover sheet. Therefore, recording and erasing can be repeated.

  Such a writing sheet can be applied to recording sheets, displays of stores, etc., educational toys, educational materials, etc., and various products have been researched and developed. For example, Patent Documents 1 and 2 disclose seats and teaching materials that can be described repeatedly.

Unexamined-Japanese-Patent No. 2010-042618 JP 2001-142387 A

  However, according to the study of the present inventors, in these writing sheets, the contrast of the recorded image is low, the contrast of the recorded image is deteriorated with the passage of time, and the adhesion is excessively high and peeling is Problems may occur such as difficulty or damage to the substrate or cover sheet during peeling, and further improvement was necessary.

The writing sheet according to the invention is
A substrate comprising a colored support and an adhesive layer formed on the surface thereof;
A writing sheet comprising a film, and a transparent cover sheet having a matte surface formed on one surface of the film, wherein the adhesive layer and the matte surface are in contact with each other. ,
The arithmetic mean height Sa of the mat surface is 0.10 to 0.50 μm.

  According to the present invention, it is possible to provide a writing sheet capable of recording high contrast images, having less change in image contrast over time, and being easy to record and erase.

BRIEF DESCRIPTION OF THE DRAWINGS The conceptual cross section of the writing sheet by this invention.

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

[Writing sheet]
A conceptual cross-sectional view of a writing sheet according to one embodiment according to the present invention is as shown in FIG. The writing sheet 100 comprises a base 110 and a cover sheet 120. The substrate 110 and the cover sheet 120 are disposed such that the surfaces face each other. Here, the base and the cover sheet may be bonded or fixed at their ends so as not to be separated from each other, and may be independent without being bonded to each other. When the substrate and the cover sheet are not bonded to each other, these combinations are referred to as a writing sheet.

  In this writing sheet, in the initial state before recording an image, the base material and the cover sheet are not in close contact, and an air layer is present at the interface between them.

  When recording an image, pressure is applied to the desired portion from the top of the cover sheet. The substrate and the cover sheet are in close contact with each other immediately below the pressurized portion. As a result, the air layer existing at the interface between the substrate and the cover sheet is substantially eliminated, and the refractive index of the interface changes.

  As a result, the refractive index changes between the interface of the unpressurized part and the interface of the pressurized part, and a contrast is generated to record an image. In general, the color of the substrate can be recognized from the top of the cover sheet in the pressurized portion. The method of pressing is arbitrary, and there is a method of pressing in a letter shape with a pen made of a resin material or the like, or a method of pressing a relief such as a stamp to transfer a pattern.

  Then, by peeling the cover sheet from the substrate, an air layer is generated again at the interface to erase the image. The cover sheet can be pulled apart and the method is optional, and the cover sheet can be pulled up from the end, or a bar can be inserted and moved between the substrate and the cover sheet.

  Thus, the writing sheet according to the present invention can repeat recording and erasing of an image.

[Base material]
The base used in the present invention comprises a colored support 111 and an adhesive layer 113 on the surface facing the cover sheet. The adhesive layer 113 is a layer in close contact with the cover sheet at the time of image recording, and by being in close contact, for example, the color of the colored support 111 can be observed from the surface of the writing sheet.

  The adhesive layer 113 is formed on at least one surface of the colored support 111. By providing adhesive layers on both sides of the colored support and combining two cover sheets facing each side, it is possible to make a writing sheet recordable on both sides.

  Here, the colored support is not particularly limited, but needs to be colored in order to keep high the contrast of the image observed from the surface of the writing sheet at the time of image recording. In addition, in order to provide the writing sheet with sufficient physical strength, the colored support is also required to have strength.

  From such a point of view, as shown in FIG. 1, in one embodiment, a colored support having a core plate 111b and a colored layer 111a can be used. By using a core plate having sufficient physical strength, it is possible to select various colored layers according to cost and color. At this time, the core plate is preferably one having 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, as (i) polyolefin resin films, polyethylene (PE) resin, polypropylene (PP) resin, ethylene-propylene copolymer, ethylene- From the butene copolymer and the like, (ii) the polyester resin can be selected from polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polyethylene naphthalate resin, polybutylene naphthalate resin and the like. Among these, polyester resins are preferable, and PET resins are particularly preferable in terms of strength and processability.

  The surface of these films may be subjected to conventionally known surface treatment such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, application of an undercoat (formation of undercoat layer), and the like.

The thickness of the core plate is not particularly limited, but preferably 50 to 250 μm in thickness in order to achieve sufficient physical strength.
These core plates may be colorless and transparent, colored and transparent, or opaque. When the core plate is colorless and transparent, it is preferable to be laminated with a colored layer. In any case, it is preferred that the colored support be totally opaque. In the present invention, being opaque means that the transmittance is less than 80%, preferably less than 60% over the entire wavelength range of 400 to 760 nm. On the other hand, being colorless and transparent means that the transmittance is 80% or more, preferably 90% or more, over the entire wavelength range. Furthermore, colored and transparent means that there is a region with a transmittance of less than 80% in a part of the wavelength region.

  When a colored layer is used to make the colored support opaque, the colored layer may be formed by laminating a colored sheet material or the like with a transparent core plate, or coloring the surface of the transparent core plate A layer may be applied and formed.

  Examples of the colored sheet-like material include colored paper, a dyed resin film, a film made of a resin material in which colored particles are dispersed, and a colored fiber aggregate. When forming a colored layer by application, a composition containing a binder in which colored particles are dispersed may be applied, and then dried or cured to form a colored layer. The colored particles include inorganic pigment particles, metal powder, metal oxide powder and the like.

  In addition, a colored support which comprises a metal plate as a colored support or a metal layer as a colored layer can also be used. When such a metal-like 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, when the recorded image is copied by a copying machine, an image with high contrast is copied. By using such an effect, it is possible to obtain the effect of a watermark picture.

  The cover sheet side surface of the colored support is preferably high in smoothness. Although an adhesive layer is provided on the surface as described later, it is preferable that the smoothness of the surface of the adhesive layer is finally high, so the cover sheet side surface of the colored support to be the base is also smooth. It is preferable that the property is high. From such a point of view, the cover sheet side surface of the colored support is preferably a resin core plate. Therefore, when the colored support has a structure in which the core plate and the colored layer are laminated, as shown in FIG. 1, the colored layer is formed on the surface opposite to the surface facing the cover sheet. Is preferred.

  The substrate 110 is provided with an adhesive layer 113. Prior to forming the adhesive layer 113 on the surface of the substrate 110, an intermediate layer 112 can be provided to improve the adhesion between the substrate and the adhesive layer. Since the writing sheet repeats adhesion and peeling between the pressure-sensitive adhesive layer and the cover sheet during use, the pressure-sensitive adhesive layer may be peeled from the surface of the substrate, but such a problem may be improved by providing the intermediate layer. It is also possible to improve the storage stability of the writing sheet.

  Materials used for the intermediate layer include various resins such as polyester resin, acrylic resin, polyurethane resin, acrylic graft polyester resin, and silicone resin. This intermediate layer can be formed of, for example, a polyester resin. By increasing the thickness of the intermediate layer, the adhesion between the substrate and the adhesive layer can be improved, and by thinning, the color of the colored support can be easily reproduced at the time of image recording. From such a viewpoint, the thickness of the intermediate layer is preferably 0.05 to 1.0 μm.

  In the substrate used in the present invention, an adhesive layer is formed on the surface of the colored support directly or on the surface via an intermediate layer. The adhesive layer adheres to the cover sheet at the time of image recording, whereby an image is recorded. Therefore, from the viewpoint of image recording stability, it is preferable that the adhesive strength is high, but if it is excessively high, peeling of the cover sheet becomes difficult at the time of erasing, or an unpleasant sound is generated at the time of peeling, The adhesive layer or the cover sheet may be damaged. Furthermore, in spite of leaving the writing sheet, the cover sheet and the adhesive layer are in close contact, and an unintended image may be recorded. Therefore, the adhesive strength 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 adhesion can be measured in accordance with the 180 ° peel adhesion measurement to the test plate shown in JIS Z 0237 Method 1.

  Such a pressure-sensitive adhesive layer is generally mixed with a pressure-sensitive adhesive composition, if necessary, a catalyst or the like, and then applied to a colored support or core plate via an intermediate layer, if necessary, It forms by heating and making it react.

  Any material can be selected from conventionally known adhesives as the material of the adhesive layer.

  Examples of such pressure-sensitive adhesives include acrylic pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives, polyester-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, polyether-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, polyamide-based pressure-sensitive adhesives and the like. Various pressure-sensitive adhesives can be mentioned.

  Among these, the silicone-based pressure-sensitive adhesive is mainly composed of a polymer whose main skeleton is mainly composed of a siloxane bond. Many silicone-based pressure-sensitive adhesives are preferable because they exhibit appropriate tackiness and are excellent in chemical resistance, water resistance and heat resistance. Furthermore, it is also preferable that silicone pressure-sensitive adhesives have a small change in adhesion due to pressure. The urethane-based pressure-sensitive adhesive is mainly composed of a polymer obtained by condensation of an isocyanate compound and a hydroxy compound. Although it is a preferable pressure-sensitive adhesive because of its excellent releasability, the adhesion is often higher than that of silicone-based pressure-sensitive adhesives, and it may be necessary to adjust the adhesion. When a urethane-based pressure-sensitive adhesive is used, the adhesion between the cover sheet and the pressure-sensitive adhesive layer tends to change depending on the pressure applied at the time of image recording. For this reason, it is preferable to use a silicone-based pressure-sensitive adhesive when the uniformity of the force required to peel the cover sheet and the uniformity of the contrast of the image to be recorded are important.

  Various pressure-sensitive adhesives used in such a method are commercially available, and suitable ones can be selected and used from them. Specifically, as silicone pressure-sensitive adhesives, LTC755, SD4580 PSA, etc. (all trade names, sold by Toray Dow Corning Co., Ltd.), KR3700, KR3701, KR3704 (all trade names, sold by Shin-Etsu Chemical Co., Ltd.) Examples of the catalyst to be combined with this include NC-25 Catalyst (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 the urethane-based pressure-sensitive adhesive include Ciavain series SH-101M, SH-101, and SP-205 (all of which are trade names and sold by Toyochem Co., Ltd.), and a catalyst to be combined therewith is Ciavain T501B (polyfunctional isocyanate Crosslinkers (trade names, sold by Toyochem Co., Ltd.).

  The catalyst to be combined with the silicone-based pressure-sensitive adhesive is preferably a noble metal catalyst containing platinum because the crosslinking density can be adjusted, and in particular, a platinum-ruthenium alloy, a platinum-palladium alloy, a platinum-titanium alloy and the like are suitably used.

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

  After application, it is preferable to carry out heating in order to accelerate the crosslinking reaction and to improve the production efficiency. The heating temperature is generally selected from the range of 40 to 150 ° C, preferably 60 to 130 ° C.

  The thicker the adhesion layer, the more easily the film adheres to the cover sheet, the thinner the reproduction of the color of the colored support during image recording, and the lower the production cost. Therefore, the thickness of the adhesive layer is preferably 5 to 30 μm, and more preferably 10 to 20 μm. Further, the surface of the adhesive layer is preferably smooth.

  In addition, the adhesion layer may be colored. By making the color of the colored support and the color of the adhesive layer different, it is possible to record an image with a color synthesized by 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, it is possible to record an image with a higher color density by a combination of the color density of the adhesive layer and the color density of the colored support. It will be possible. Furthermore, the adhesive layer can also have the function of a colored layer. That is, it is also possible to omit providing a colored layer separately by providing a color of high concentration to the adhesive layer.

[Cover sheet]
When the cover sheet 120 used in the present invention is in close contact with the adhesive layer 113, the color of the base material needs to be observable from the surface of the writing sheet. For this reason, the cover sheet needs to be transparent. In general, the cover sheet is preferably colorless and transparent. The high transmittance of the cover sheet over the entire wavelength range of 400 to 760 nm enables an image recording faithful to the color applied to the substrate. However, it is also possible to color the cover sheet. If a cover film having transparency in a part of the wavelength range of 400 to 760 nm is used, it is possible to record an image in a color different from the color applied to the substrate.

  Such cover sheets generally comprise a transparent film. The cover sheet is required not only for transparency but also for physical strength, so a film made of the material exemplified for the above-mentioned colored support is preferably used.

  In the present invention, a mat surface is formed on the adhesive layer side surface of the cover sheet. The characteristics of the writing sheet vary greatly depending on the surface shape of the matte surface.

  In the writing sheet according to the present invention, when the arithmetic average height Sa of the mat surface is large, the matte expression is facilitated, and even when the writing sheet is left, the cover sheet and the adhesive layer are not in close contact with each other. With a small value, it tends to be possible to form an image with high contrast. From such a viewpoint, in the present invention, the arithmetic average height Sa of the mat surface is 0.10 to 0.50 μm, and preferably 0.15 to 0.30 μm.

  The arithmetic mean height Sa can be measured by a three-dimensional roughness meter. Specifically, a laser microscope LEXT-OLS 4100 (trade name, manufactured by Olympus Corporation) can be used for these measurements.

  Furthermore, the unevenness present on the mat surface prevents adhesion between the adhesive layer and the cover sheet before image recording, and in the case of image recording, the adhesion between the adhesive layer and the cover sheet is appropriate. In addition, the image can be easily peeled off at the time of image deletion. In order to obtain such a matte surface, the haze value is preferably 70 to 95%. The haze value can be measured with a haze meter TC-HIII (trade name, manufactured by Tokyo Denshoku Co., Ltd.).

  Although the method of forming the mat surface 121 on the surface of the cover sheet 120 is not particularly limited, the method of directly etching the surface of the film which is the main structure of the cover sheet, the method of laminating with the film having irregularities, fine particles Is applied to the film surface and dried or cured to form an irregular surface, a composition containing a compound that generates air bubbles by heating is applied to the film surface, and the composition is heated. There is a method of generating air bubbles in an object layer to form asperities on the surface. Moreover, the cover sheet in which the mat surface was formed in the surface can also be obtained by shape | molding the resin composition in which microparticles | fine-particles were disperse | distributed to a film form as a cover film.

  Among these, it is preferable to use a resin composition in which fine particles are dispersed, because control of the roughness of the mat surface is easy. In particular, a method in which a resin composition in which fine particles of high transparency such as silica are dispersed is applied to the surface of a film and heated to cure the resin is preferably adopted in terms of quality stability and characteristics of the cover film. Ru. The fine particles may be organic or inorganic materials. Examples of the organic material used for the fine particles include acrylic resins such as polymethyl methacrylate, polystyrene, styrene-acrylic resin, polycarbonate resin, urethane resin, epoxy resin, polyester resin, polyester urethane resin and the like. Moreover, as an inorganic material used for microparticles | fine-particles, a silicon dioxide (silica), a titanium dioxide, barium sulfate, calcium carbonate, a talc, mica | cuttle-fish, metal flakes, metal oxide flakes etc. are mentioned, for example. Among these, particularly when mica, metal flakes or metal oxide flakes are used, the color produced at the time of image recording becomes metallic and it is characterized that a beautiful image is recorded. In this case, it is preferable to make the colored layer a high density color, typically black, since the contrast is increased and the metallic color is observed more beautifully.

  It is preferable that the average particle diameter of these microparticles | fine-particles is 0.05-5.0 micrometers. Here, the average particle size is measured on a volume basis by a laser diffraction method (principle), and can be measured, for example, by MICROTRAC 9320-X100 (manufactured by Honeywell).

  Moreover, as resin used as a binder of a composition, vinyl chloride vinyl acetate copolymer resin, an epoxy resin, an acrylic resin, a polyester resin, a urethane resin, a melamine resin etc. are mentioned. Among these, acrylic melamine resin, polyester melamine resin, acrylic urethane resin and the like are considered to be excellent in terms of physical strength and optical properties, and are preferably used.

  Further, examples of the solvent for dissolving or dispersing these include toluene and methyl ethyl ketone.

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

  Also, methods of directly etching the film surface include physical methods and chemical methods. Among them, the physical method is preferable because the process is relatively simple and finer irregularities can be formed. Examples of the method of physically etching the film surface include a sand blast method and a scratch method.

  In the present invention, the hardness of the matte surface of the cover sheet is preferably high. Specifically, the pencil hardness (JIS K 5600-5-4) is preferably F or more, and more preferably H or more. According to the study of the present inventors, in the case of a writing sheet, when the image is recorded and then erased, a trace of the image may be left on the cover sheet. As a result, the contrast of the recorded image to be formed later is lowered. However, in the present invention, such a problem is improved by appropriately setting the hardness of the matte surface, and such a decrease in contrast is suppressed. Furthermore, the adhesion between the cover sheet and the adhesive layer can be made appropriate to facilitate image recording and erasing.

  The side opposite the matte side of the cover sheet is subjected to pressure and stress during image recording. When pressing with a stamp or the like, a force in the direction perpendicular to the surface of the writing sheet is applied. On the other hand, when recording an image with, for example, a pen or the like, a force in the vertical direction is applied to bring the cover sheet and the adhesive surface into close contact, but at the same time the friction force between the surface of the cover sheet and the pen tip. Occurs. As a result, the cover sheet surface may be damaged and the contrast of the recorded image may be reduced. In order to prevent such a problem, the cover sheet used in the present invention preferably has a surface protective layer 123 on the surface opposite to the surface on which the mat 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 sheet, or applying and curing a composition containing a resin material. In particular, since various surface protective films are commercially available, it is convenient to use one of them according to the purpose. As such a protective film, those having high hardness to protect the surface, those having low surface friction to prevent generation of scratches, having appropriate elasticity, and having physical shock relaxation or physical properties In some cases, it is self-healing while being damaged once. The surface protection film having high hardness is, for example, a film made of hard plastic, and the specific hardness is preferably HB or more in pencil hardness. Moreover, as a film with low frictional force, the film which consists of high molecular weight polyethylene with a smooth surface, for example is mentioned, It is preferable that the friction coefficient of the surface is 0.15 or less specifically ,. Also, the film that reduces physical impact or self-repairing is a film made of a polymeric material such as silicone resin, having a flexible structure. In the present invention, it is preferable to use a surface protection film that combines some of these properties. As such films, various films such as tough top self-healing coated film SR-TEBF (trade name, manufactured by Toray Film Processing Co., Ltd.), Tokuro HC film hard coated product HC1000 (manufactured by Toyo Cross Co., Ltd.), etc. are commercially available ing.

  The thickness of the cover sheet is preferably thin in order to achieve high transparency and to transfer the pressure during image recording to the interface between the cover sheet and the adhesive layer, and to increase the physical strength. It is preferable to be thick. From such a viewpoint, the thickness of the main film constituting the cover sheet is preferably 38 to 100 μm, and more preferably 50 to 75 μm. Moreover, when providing a mat coat layer, in order to obtain the target surface roughness, it is preferable to thicken a mat coat layer, in order to maintain the transparency of a cover sheet, it is preferable that a mat coat layer is thin. From such a viewpoint, the thickness of the matte coat layer is preferably 2 to 20 μm, and more preferably 5 to 10 μm. When a surface protective layer is provided, the thickness of the surface protective layer is preferably 0 to 100 μm, and more preferably 25 to 50 μm.

  The present invention will be described below using examples.

Example 1
90 parts of a silicone-based adhesive (LTC 755 Coating (trade name), Toray Dow Corning Co., Ltd.), a silicone-based adhesive (SD 4580 PSA (trade name), Toray, on a 50 μm thick polyester film (core plate) -Dissolve 10 parts of Dow Corning Co., Ltd., and 0.7 parts of platinum catalyst (NC-25 (trade name), Toray Dow Corning Co., Ltd.) in toluene, stir the solution sufficiently, and coat with an applicator And cured at 120 ° C. for 2 minutes to form a transparent adhesive layer having 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 substrate.

Moreover, the coating liquid containing polyester melamine resin and a silica particle was coated on the back surface of the film made from polyester with a thickness of 50 micrometers, and the cover sheet 1 in which the mat surface was formed on the surface was obtained. The sheet had a Sa of 0.15 μm, a haze value of 72.8 and a pencil hardness of H.
A writing sheet was prepared by combining this base material and a cover sheet.

[Examples 2 to 7 and Comparative Examples 1 to 2]
The raw material of an adhesion layer and the formation method of the mat surface of a cover sheet were changed with respect to Example 1, and the writing sheet of Example Examples 2-7 and Comparative Examples 1-2 was created. The raw materials of the adhesive layer were as shown in Table 1. Moreover, the cover sheets 2-6 were manufactured as follows.
Cover sheet 2: A coating liquid containing a polyacrylmelamine resin and silica particles was coated on the back surface of a 50 μm thick polyester film to obtain a cover sheet 2 having a matte surface formed on the surface. The sheet had a Sa of 0.24 μm, a haze value of 80.0, and a pencil hardness of F.
Cover sheet 3: The cover sheet 3 was obtained by changing the type and the blending amount of the polyester melamine resin and the silica fine particles with respect to the cover sheet 1. The sheet had a Sa of 0.29 μm, a haze value of 77.0, and a pencil hardness of H.
Cover sheet 4: The surface of a 50 μm-thick polyester sheet was sandblasted to form a mat surface, and a cover sheet 4 was obtained. The sheet had a Sa of 0.11 μm, a haze value of 76.2 and a pencil hardness of 6 B.
Cover sheet 5: The cover sheet 5 was obtained by changing the type and blending amount of the polyacrylmelamine resin and the silica fine particles with respect to the cover sheet 2. The sheet had a Sa of 0.07 μm, a haze value of 60.0, and a pencil hardness of H.
Cover sheet 6: A light diffusion polyethylene terephthalate sheet (Light Up LDE 50 μm (trade name), manufactured by Kimoto Co., Ltd.) was used as the cover sheet 6. The sheet had a Sa of 0.95 μm, a haze value of 91.0, and a pencil hardness of 6 B.

[Evaluation]
After storage of the writing sheet, it was allowed to stand and the state change was visually evaluated.
A: No sticking of the adhesive layer and the matte layer
B: The adhesive layer and the mat layer stick with time.
C: Adhesive layer and matte layer stick.

Writing Performance The recorded image when written with the writing tip of the fiber bundle was visually evaluated.
A: Good recorded image is obtained.
B: A recorded image is obtained but the contrast is low.
C: The recorded image did not remain even after writing, or disappeared spontaneously immediately after writing.

Erase Performance The matte layer and the adhesive layer were peeled off after recording, and the degree of difficulty of peeling when the recorded image was erased was evaluated.
A: The recorded image can be erased easily and cleanly with a light force.
B: The image can not be erased without a large peeling force. Or there is a loud peeling noise. C: The cover sheet or adhesive layer is damaged during erasing.
Recording Performance After recording an image, the recorded image after one day passed was visually evaluated.
A: There is no change in the recorded image.
B: The image became unclear compared to immediately after recording.
C: The recorded image is not visible (image has been lost).

100 writing sheet
DESCRIPTION OF SYMBOLS 110 base material 111 coloring support body 111a coloring layer 111b core plate 112 middle class 113 adhesion layer 120 cover sheet 121 mat surface 121a mat coat layer 122 film base material 123 surface protective layer

Claims (7)

A substrate comprising a colored support and an adhesive layer formed on the surface thereof;
A writing sheet comprising a film, and a transparent cover sheet having a matte surface formed on one surface of the film, wherein the adhesive layer and the matte surface are in contact with each other. ,
The writing sheet, wherein the arithmetic mean height Sa of the matte surface is 0.10 to 0.50 μm.   The writing sheet of Claim 1 whose hardness of the said mat | matte surface is pencil hardness F or more.   The writing sheet according to any one of claims 1 and 2, wherein the matte surface is the surface of a fine particle-containing layer disposed on the surface of the film.   The writing sheet according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive layer comprises a silicone-based pressure-sensitive adhesive.   The writing sheet according to any one of claims 1 to 4, wherein the adhesive strength of the adhesive layer is 1.0 to 5.0 N / m.   The writing sheet according to any one of claims 1 to 5, wherein the cover sheet comprises the film and a matte coat layer formed on the surface thereof.   The writing sheet according to any one of claims 1 to 6, further comprising a surface protective layer on the surface of the cover sheet opposite to the surface on which the mat surface is formed.

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