JP2010046961A - Writing sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide writing sheet which has writability, erasability, and anti-glare which are required properties for a sheet to be used as a white board and also as a screen, and generates no cracks on the sheet surface as well as effectively preventing scars on the surface. <P>SOLUTION: The writing sheet includes a surface clear layer having ruggedness by embossing, a base film layer, and an adhesive layer. The surface clear layer is a coating film containing a resin whose component is ultraviolet ray setting oligomer and/or ultraviolet ray setting monomer each having a fluorinated functional group, wherein the resin contains 0.02-0.1 mass% fluorine in terms of solid content. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a writing sheet. In detail, it is related with the writing sheet which consists of a surface clear layer which has the unevenness | corrugation by embossing, a base film layer, and an adhesive layer.

Sheets used as whiteboards and screens have been put into practical use.
Such a sheet can be written with a marker as a whiteboard (writing property), and characters written with the marker can be erased with an eraser (erasability), and further, as a screen, an image projected by various projectors Is required to be visible (antiglare) without being dazzling.

  Patent Document 1 describes a writing board / reflective screen-use sheet having an ultraviolet curable resinous film composed of an acrylic monomer on a base material and embossed from the front side or the back side of the base material. Has been. The resin constituting the film of this sheet does not contain fluorine.

In Patent Document 2, embossing is transferred by an embossing plate onto the surface of a laminate film, which is a laminate of a white film and a fluorine film that has been hydrophilically or polarity-enhanced by irradiation with an activating light beam. A whiteboard sheet is described.
International Publication No. 01/32440 Pamphlet Japanese Patent Application Laid-Open No. 11-254885

  The present invention provides a writing sheet that has the required writing characteristics, erasability and anti-glare properties required for a sheet used as a whiteboard and screen, and that does not cause cracks on the sheet surface and is less susceptible to scratches on the surface. The purpose is to do.

  That is, the present invention comprises a surface clear layer having an unevenness by embossing, a base film layer, and an adhesive layer, and the surface clear layer has an ultraviolet curable oligomer having a fluorine functional group and / or a fluorine functional group. It is a coating film containing a resin having an ultraviolet curable monomer as a constituent element, and the resin provides a writing sheet containing 0.02% by mass to 0.1% by mass of fluorine in terms of solid content. .

  The writing sheet of the present invention is a sheet that can be used as a whiteboard and screen that is excellent in writability, erasability, antiglare properties, has no cracks on the surface of the sheet, has excellent scratch resistance, and does not easily scratch the surface. Can be provided.

  The writing sheet of this invention consists of a surface clear layer, a base film layer, and an adhesive layer. These layers are preferably laminated in the order of the surface clear layer, the base film layer, and the pressure-sensitive adhesive layer, and a liner may be further laminated so as to be in contact with the pressure-sensitive adhesive layer.

  The surface clear layer includes a resin having an ultraviolet curable oligomer having a fluorine functional group and / or an ultraviolet curable monomer having a fluorine functional group as a constituent element. That is, the resin includes an ultraviolet curable oligomer having a fluorine functional group, an ultraviolet curable monomer having a fluorine functional group, or an ultraviolet curable oligomer having a fluorine functional group and an ultraviolet curable monomer having a fluorine functional group. The mixture can be a component. Alternatively, a mixture of an ultraviolet curable oligomer having a fluorine functional group and an ultraviolet curable monomer having no fluorine functional group, an ultraviolet curable acrylic oligomer having no fluorine functional group and an ultraviolet curable type having a fluorine functional group Mixtures with these monomers can also be used as constituents. In any case, a known photopolymerizable monomer, a known polymer, and / or a known photopolymerization initiator may be further contained.

  And said resin contains about 0.02 mass%-about 0.1 mass% fluorine in conversion of solid content. By containing such a content of fluorine, the writing property and erasability of the writing sheet are improved, and cracks are hardly generated on the surface of the surface clear layer. The fluorine content may be about 0.02% to about 0.1% by weight, for example, about 0.02% to about 0.09%, about 0.03% to about 0.09%, or It can be about 0.033 mass% to about 0.084 mass%.

  As the ultraviolet curable oligomer having a fluorine functional group, an oligomer having a fluorine functional group and having a molecular weight of about 400 to about 10,000 that is crosslinked and cured by irradiation with ultraviolet rays can be used. Examples of such oligomers include acrylic oligomers and acrylic urethane oligomers. Furthermore, examples of the acrylic oligomer include epoxy acrylate, polyester acrylate, and polyurethane acrylate, and examples of the acrylic urethane oligomer include polyether urethane acrylate. In the resin, the content of the oligomer can be appropriately selected so that the fluorine content in the resin becomes a desired value and the surface clear layer of the present invention can be formed, and is not particularly limited. For example, it may be about 5% by mass to about 80% by mass (in terms of solid content) of the whole resin.

  As the ultraviolet curable monomer having a fluorine functional group, a monomer having a fluorine functional group and capable of crosslinking and curing by irradiation with ultraviolet rays can be used. Examples of such monomers include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl acryloyl phosphate, 1,3-butanediol diacrylate, 1 having fluorine functional group substitution, , 4-Butanediol diacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, tripropylene glycol diacrylate, neobendyl glycol diacrylate, polyethylene glycol 400 diacrylate, hydroxybivalate ester neobendyl glycol di Acrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate , It is possible to use one or more selected from isophorone diisocyanate (IPDI), or acryloyl morpholine. In the resin, the content of the monomer can be appropriately selected so that the fluorine content in the resin becomes a desired value and the surface clear layer of the present invention can be formed, and is not particularly limited. For example, it may be about 5% by mass to about 80% by mass (in terms of solid content) of the whole resin.

  When the ultraviolet curable oligomer having a fluorine functional group and the ultraviolet curable acrylic monomer having a fluorine functional group are used at the same time, the total of these is about 80 mass% to about 99.5 mass% in the resin ( Solid content conversion).

  As the ultraviolet curable oligomer having no fluorine functional group, an oligomer having no fluorine functional group and having a molecular weight of about 400 to about 10,000 that is crosslinked and cured by irradiation with ultraviolet rays can be used. Examples of such oligomers include acrylic oligomers and acrylic urethane oligomers. Furthermore, examples of the acrylic oligomer include epoxy acrylate, polyester acrylate, and polyurethane acrylate, and examples of the acrylic urethane oligomer include polyether urethane acrylate. The content of the oligomer can be appropriately selected so that the fluorine content in the resin becomes a desired value and the surface clear layer of the present invention can be formed, and is not particularly limited. For example, it may be about 5% by mass to about 80% by mass (in terms of solid content) of the whole resin.

  As the ultraviolet curable monomer having no fluorine functional group, a monomer that does not have a fluorine functional group and can be crosslinked and cured by irradiation with ultraviolet rays can be used. Such monomers include, for example, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl acryloyl phosphate, 1,3-butanediol diacrylate, having no fluorine functional group substitution. 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, tripropylene glycol diacrylate, neobendyl glycol diacrylate, polyethylene glycol 400 diacrylate, hydroxybivalate ester neobendyl glycol Diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate DOO, may be used one or more selected from isophorone diisocyanate (IPDI), or acryloyl morpholine. In the resin, the content of the monomer can be appropriately selected so that the fluorine content in the resin becomes a desired value and the surface clear layer of the present invention can be formed, and is not particularly limited. For example, it may be about 5% by mass to about 80% by mass (in terms of solid content) of the whole resin.

  Examples of the fluorine functional group contained in the ultraviolet curable oligomer having a fluorine functional group or the ultraviolet curable monomer having a fluorine functional group include, for example, hydrogen of a linear or branched alkyl group having 1 to 12 carbon atoms. Mention may be made of fluoroalkyl groups in which at least one of the atoms has been replaced by a fluorine atom.

Specific examples of such a fluoroalkyl group include 2,2,3,3,3-pentafluoropropyl, 2- (perfluorohexyl) ethyl, 2- (perfluorooctyl) ethyl, and 2- (perfluorohexyl). Fluorodecyl) ethyl, 6- (perfluoroethyl) hexyl, 6- (perfluorobutyl) hexyl, 6- (perfluorohexyl) hexyl, 6- (perfluorooctyl) hexyl, 2,2,3,4,4 , 4-hexafluorobutanol, 2,2,3,3-tetrafluoropropyl, 2- (perfluoro-3-methylbutyl) ethyl, 2- (perfluoro-5-methylhexyl) ethyl, 2- (perfluoro- 7-methyloctyl) ethyl, 6- (perfluoro-1-methylethyl) hexyl, 2- (perfluoro-3-methylbutyrate) ) Hexyl, 6- (perfluoro-5-methylhexyl) hexyl, or 6- (perfluoro-7-methyl-octyl), and hexyl.
As the known photopolymerizable monomer, those conventionally used as a surface layer or surface coating of a laminated film can be appropriately used, and are not particularly limited. The content of such a monomer is not particularly limited, and can be, for example, about 5% by mass to about 50% by mass (in terms of solid content) of the entire resin.

  As the known polymer, those conventionally used as a surface layer or a surface coating of a laminated film can be appropriately used, and are not particularly limited. The content of such a polymer is not particularly limited, but can be, for example, about 5% by mass to about 50% by mass (in terms of solid content) of the entire resin.

  As the photopolymerization initiator, a conventionally known initiator can be used. Specifically, for example, 1-hydroxycyclohexyl phenyl ketone (Irgacure (R) 184 manufactured by Ciba Specialty Chemicals), 2, 2 -Dimethoxy-2-phenylacetophenone (Irgacure (R) 651 manufactured by Ciba Specialty Chemicals), 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Darocure (R) manufactured by Ciba Specialty Chemicals (R) 1173), 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (Irgacure (R) 907 manufactured by Ciba Specialty Chemicals), 2-benzyl-2-dimethylamino -1- (4-morpholinophenyl) -butan-1-one, 2-c Rothioxanthone, 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, isopropylthioxanthone, 2,4,6-trimethylbenzoyldiphosphine oxide, or bis (2,6-dimethoxybenzoyl) -2,4,4- Examples thereof include trimethylpentylphosphine oxide. These initiators can be used alone or in combination of two or more.

  The content of the photopolymerization initiator in the ultraviolet curable acrylic resin composition of the present invention is about 0.5% to about 20% by weight, or about 1% to about 10% by weight (solid content) Conversion).

Specifically, as the resin constituting the surface clear layer, for example,
Seika Bond P-1301 (manufactured by Dainichi Seika Kogyo Co., Ltd .: polyether urethane acrylate, acrylic monomer, and photopolymerization initiator, resin not containing fluorine functional group: solid content 80%),
SN-5X-7624 (manufactured by San Nopco: polyether urethane acrylate, photopolymerizable monomer, polyester urethane, and photopolymerization initiator, and no fluorine functional group resin: solid content 40%), and adekatopomer KR566 (manufactured by ADECA Corporation: resin containing acrylic monomer and photopolymerization initiator and not containing fluorine functional group: solid content 80%)
And one selected from
Examples thereof include a mixture with Defender FH-800ME (Dainippon Ink Co., Ltd .: fluorine functional group-containing urethane acrylate, photopolymerizable monomer, and photopolymerization initiator: solid content 90%).

The content of each resin is, for example,
One selected from Seica Bond P-1301, SN-5X-7624, and Adekaoptomer KR566 is about 100 parts by mass,
The defender FH-800ME can be about 25 parts by mass to about 100 parts by mass.

  The surface clear layer of this invention has the unevenness | corrugation by embossing in the surface on the opposite side to a base film layer. Therefore, the glossiness of the surface of the surface clear layer is suppressed, and when the writing sheet of the present invention is used as a projector, the surface clear layer is not dazzled, and images projected on the writing sheet can be viewed from various angles. Specifically, it is preferable that the 60-degree specular glossiness of the surface clear layer surface is about 30% or less, or about 10% to about 30%, in which normal glare is not felt.

  The embossed irregular shape may be random or regular, and is not particularly limited. For example, the arithmetic average roughness (Ra) (JIS B 0601-2001) is about 1 μm to about 5 μm, and the average spacing (Sm) between convex portions (JIS B 0601-1994) is about 200 μm to about 800 μm. The maximum cross-sectional height (Rt) (JIS B 0601-2001) can be about 1 μm to about 30 μm.

  More preferably, the arithmetic average roughness (Ra) (JIS B 0601-2001) is about 1 μm to about 5 μm, and the average spacing (Sm) between convex portions (JIS B 0601-1994) is about 200 μm to about 800 μm. In addition, the maximum cross-sectional height (Rt) (JIS B 0601-2001) can be set to about 1 μm to about 30 μm.

  The surface clear layer of the present invention can be produced by applying, polymerizing and drying the resin composition solution on the surface of the base film layer by a conventionally known method. For example, the ultraviolet curable oligomer having a fluorine functional group and / or the ultraviolet curable monomer having a fluorine functional group and, if necessary, a photopolymerizable monomer and / or a photopolymerization initiator are mixed in a solvent. It can be manufactured by preparing a composition solution, applying and curing on a film to be a base film layer, and further embossing.

  Application of the composition solution can be performed by a conventionally known coating method such as bar coating such as wire bar coating, knife coating, or gravure coating. The composition solution can be cured using a UV oven or the like. The embossing will be described below.

  A conventionally well-known method can be employ | adopted for the said embossing. Usually, the sheet | seat which laminated | stacked the surface clear layer and the base film layer is pinched | interposed between the embossing roll and the backup roll, and it carries out so that the pattern of the embossing roll surface may be transcribe | transferred to the surface clear layer surface. The embossing is preferably performed while heating. The heating temperature is not particularly limited as long as it is appropriately adjusted in accordance with the characteristics of the resin used and the like within a conventionally known range. For example, about 50 ° C. to about 270 ° C. can be used. Moreover, the pressure of the roll at the time of embossing can also be selected from a conventionally well-known range, and is not specifically limited. For example, it can be selected from the range of about 0.4 MPa to about 1.0 MPa.

  The backup roll may be made of the same material as the processing roll, but usually uses a soft roll formed by wrapping a surface covering material made of a flexible material such as rubber or cotton around the surface of a metal roll. be able to. The other processing conditions are in accordance with a general method for embossing the surface of the protective layer of a conventional sheet.

  The thickness of the surface clear layer is not particularly limited, and can be, for example, about 2 μm to about 20 μm, or about 2 μm to about 6 μm.

  As the base film layer of the present invention, a film made of a thermoplastic resin can be used. Examples of the thermoplastic resin include vinyl chloride resins, vinyl chloride-vinyl acetate resins, acrylic resins, polyester resins such as PET and PET-G, and cellulose resins. If these films are white, the writing sheet of the present invention is a whiteboard-like sheet, but is not limited to white. A film having a desired color can be used as long as the color of the marker is visible.

  Although the thickness of the said base film layer is not specifically limited, For example, it can be set as about 50 micrometers-about 300 micrometers.

  The pressure-sensitive adhesive layer of the present invention comprises a conventionally known pressure-sensitive adhesive. Although it does not specifically limit as such an adhesive, For example, an acrylic adhesive, a polyester adhesive, a rubber adhesive, a silicone adhesive, or a polyurethane adhesive etc. can be mentioned.

  The pressure-sensitive adhesive layer is formed, for example, by preparing a pressure-sensitive adhesive layer with a liner having a pressure-sensitive adhesive layer formed on the release surface of the liner, and dry laminating the pressure-sensitive adhesive layer and the base film layer. The

  Although the thickness of the said adhesive layer is not specifically limited, For example, it can be set as about 5 micrometers-about 200 micrometers.

  In the writing sheet of the present invention, a liner can be further laminated on the outer surface of the pressure-sensitive adhesive layer. Such a liner may be one generally used in the field such as an adhesive tape, and is not limited to a specific member. Suitable liners include, for example, paper, for example, plastic materials such as polyethylene, polypropylene, polyester, or cellulose acetate, or paper or other materials coated or laminated with such plastic materials. it can. These liners may be used as they are, but they can be used after being treated with a silicone treatment or other methods to improve the release characteristics.

  The writing sheet of this invention can be manufactured by selecting a conventionally well-known method suitably. An example is described below.

  First, the laminated body of the surface clear layer and base film layer which have the unevenness | corrugation by embossing on the surface created as mentioned above is prepared. Subsequently, a pressure-sensitive adhesive solution is applied to the liner by a known method and dried to form a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive surface is laminated on the surface of the base film layer opposite to the surface clear layer, Get a writing sheet.

  The thickness of the entire writing sheet is not particularly limited, and can be, for example, about 80 μm to about 500 μm.

  The writing sheet of the present invention has both functions of a writing board represented by a white board and the like and a screen for various projectors. By sticking to a whiteboard base or the like, it can be used as a movable writing board and screen. Moreover, it can also be used as wallpaper by sticking the said writing sheet directly on a wall surface. In the latter case, the wall of the conference room or the like becomes the writing board and screen as it is, which can contribute to space saving.

Production of coating composition Coating composition 1: 100 parts of Seika Bond P-1301 (solid content 80%, manufactured by Dainichi Seika Kogyo Co., Ltd.), Defender FH-800ME (solid content 90%, manufactured by Dainippon Ink Co., Ltd.) Were mixed at a mass ratio of 25 parts, and the mixed solution was diluted 2-fold with methyl ethyl ketone.
Coating compositions 2 to 6: Prepared in the same manner as coating composition 1. The content of each component was as shown in Table 1.
Coating composition 7: 100 parts of Adekaoptomer KR566 (solid content 80%, manufactured by ADECA) was diluted 2-fold with methyl ethyl ketone.
Coating composition 8: Defenser FH-800ME (solid content 90%, manufactured by Dainippon Ink Co., Ltd.) at a weight ratio of 25 parts to 100 parts of SN-5X-7624 (solid content 40%, manufactured by San Nopco Co., Ltd.) Mixing was performed, and the mixed solution was diluted 2-fold with methyl ethyl ketone. The content of each component was as shown in Table 1.
Coating compositions 9 to 12: Prepared in the same manner as coating composition 8. The content of each component is as shown in Table 1.

Examples 1-4
Coating compositions 1 to 4 were each applied to a white PET-G film (manufactured by Achilles Co., Ltd.) having a thickness of 100 μm with a wire bar so that the thickness after drying was 5 μm, and UV oven (manufactured by Fusion UV System) ) To form a surface clear layer on the base film layer. Subsequently, embossing was performed so that the embossing roll was in contact with the surface clear layer side of the obtained sheet. The liner was coated with an acrylic pressure-sensitive adhesive (butyl acrylate: acrylic acid = 90: 10, mass ratio, solid content 32%) so that the thickness after drying was 40 μm, and a pressure-sensitive adhesive layer was prepared. The resulting sheet was laminated on the base film layer side to obtain a writing sheet. Ra, Sm, and Rt were values shown in Table 2.

Example 5
A writing sheet was obtained in the same manner as in Example 1 except that Ra, Sm, and Rt were embossed so as to have the values shown in Table 2.

Examples 6-9
A writing sheet was obtained in the same manner as in Example 1 except that the coating compositions 8 to 11 were used and Ra, Sm, and Rt were embossed so as to have the values shown in Table 2.

Comparative Example 1
A writing sheet was obtained in the same manner as in Example 1 except that the embossing was not performed.

Comparative Example 2
A writing sheet was obtained in the same manner as in Example 1 except that Ra, Sm, and Rt were embossed so as to have the values shown in Table 2.

Comparative Example 3
A writing sheet was obtained in the same manner as in Example 1 except that the coating composition 5 was used.

Comparative Example 4
A writing sheet was obtained in the same manner as in Example 1 except that the coating composition 6 was used.

Comparative Example 5
A writing sheet was obtained in the same manner as in Example 1 except that the coating composition 7 was used.

Comparative Example 6
A writing sheet was obtained in the same manner as in Example 6 except that the coating composition 12 was used.

Comparative Example 7
A laminated body was obtained by laminating a 25 μm thick ethylene tetrafluoroethylene copolymer resin film (Asahi Glass Co., Ltd.) on one side of a white PET-G film (Achilles Co., Ltd.) having a thickness of 100 μm. The laminate was embossed so that the embossing roll was in contact with the ethylenetetrafluoroethylene copolymer resin film side. The liner is coated with an acrylic pressure-sensitive adhesive (butyl acrylate: acrylic acid = 90: 10, mass ratio, solid content 32%) so that the thickness after drying is 40 μm. A pressure-sensitive adhesive surface was laminated on the PET-G film side of the body to obtain a writing sheet. Ra, Sm, and Rt were values shown in Table 2.

Arithmetic average roughness (Ra) measurement About each sheet | seat obtained by the Example and the comparative example, it measured using the handy surf (made by Tokyo Seimitsu Co., Ltd.). The results are shown in Table 2.

Measurement of average distance between convex parts (Sm) and maximum cross-sectional height (Rt) For each sheet obtained in Examples and Comparative Examples, a high-performance non-contact three-dimensional surface roughness measuring system (manufactured by Nippon Biko Co., Ltd.) ). The results are shown in Table 2.

With writability test Whiteboard Marker (pilot Co. WBMAR-12L-B supplemented type in shape large black), write a line of 5cm on the sheet surface was evaluated whether on its line a magnetic visually. When there was no repelling, it was marked as ◯, and when there was a repelling, it was marked as x. The results are shown in Table 3.

Erasability tester Tester Sangyo Co., Ltd., made by Gakushin Abrasion Tester, friction material: PLUS exclusive eraser (made by Plus Co., Ltd.) cut out fabric part, vertical load: 500g, whiteboard marker replenishment type Using large black (WBMAR-12L-B Pilot Co., Ltd.), it was evaluated whether the straight line disappeared visually after the sheet surface having a 5 cm straight line written on the sheet surface was worn once. When the straight line disappeared, it was marked as ◯, and when it did not disappear, it was marked as x. The results are shown in Table 3.

With cracks presence Tester Sangyo Co., Ltd. Science vibration abrader surface clear layer, the friction member: that cut the dough portion of the PLUS dedicated eraser (manufactured by PLUS Corporation), the vertical weight: at 500 g, pre Whiteboard Marker A replenishment type medium size large black (WBMAR-12L-B manufactured by Pilot Co., Ltd.) was used to evaluate whether or not the straight line disappeared visually after the sheet surface having a 5 cm straight line written on the sheet surface was worn once. When the straight line disappeared (no crack), it was marked as ◯, and when the straight line did not disappear (because there was a crack, a marker entered the crack), it was marked as x. The results are shown in Table 3.

Using scratch resistance test Tester Sangyo Co. Science vibration abrasion tester, friction material (steel wool # 0000) after the surface of each sheet obtained in Examples and Comparative Examples were worn reciprocally 10 times with normal weight 500g The condition of scratches was evaluated visually. When the scratch was not visible, it was marked as ◯, and when the scratch was visible, it was marked as x. The results are shown in Table 3.

For each sheet obtained in the gloss measurement Examples and Comparative Examples were measured 60 ° specular glossiness using a portable gloss meter (Murakami Ltd. Color Research Laboratory). The results are shown in Table 3.

Claims (6)

  It consists of a surface clear layer having unevenness by embossing, a base film layer, and an adhesive layer, and the surface clear layer has an ultraviolet curable oligomer having a fluorine functional group and / or an ultraviolet curable monomer having a fluorine functional group. A writing sheet containing a resin having a component as a component, and the resin contains 0.02% by mass to 0.1% by mass of fluorine in terms of solid content.   The writing sheet according to claim 1, wherein the ultraviolet curable oligomer having a fluorine functional group is an acrylic oligomer or an acrylic urethane oligomer.   The writing sheet according to claim 1 or 2, wherein the arithmetic average roughness (Ra) of the unevenness by the embossing is 1 µm to 5 µm.   The writing sheet according to any one of claims 1 to 3, wherein an average interval (Sm) between the convex and concave portions by the embossing is 200 µm to 800 µm.   The writing sheet according to any one of claims 1 to 4, wherein a maximum cross-sectional height (Rt) of the unevenness by the embossing is 1 µm to 30 µm.   The writing sheet according to any one of claims 1 to 5, wherein the surface clear layer surface has a 60-degree specular gloss of 30% or less.