JP2010131762A - Laminate sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate sheet having a concealing part by which information confidentiality is further improved. <P>SOLUTION: The laminate sheet including a thermosensitive sheet and a transparent or translucent sheet formed on the thermosensitive sheet has the concealing part including a white concealing layer, a character tint pattern layer, a camouflage tint pattern layer, and a resin layer in at least a part of a side on the transparent or translucent sheet and opposite to the thermosensitive sheet. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laminated sheet that can conceal written information.

  In general, when information that is not desired to be known by anyone other than the person himself / herself is written on a postcard and mailed, the information leakage becomes a problem. In particular, notifications from national and local governments (eg, pension notifications); billing charges for electricity, water, gas, telephone, communications, and other services; notifications from banks or post offices (eg, deposit balances) Notifications, time deposit savings notifications, etc.); misuse if the information contained in a notification from a credit sales company (for example, a reminder or a debt notification) is known to anyone other than the sender and recipient It is also a social problem. These notifications can also be made with a sealed letter, but costs such as postage and labor costs increase.

  Therefore, conventionally, the information described on the postcard is concealed from above to prevent information leakage and reduce costs. For example, Japanese Laid-Open Patent Publication No. 64-16691 (Patent Document 1) discloses an adhesive double-fold adhesive postcard via a transparent film. Japanese Laid-Open Patent Publication No. 2-289393 (Patent Document 2) discloses a re-peelable pressure-sensitive adhesive postcard characterized in that the entire or part of the edge portion of the joint has a larger peeling force than the non-edge portion. Is disclosed.

  However, all of these conventional information concealing postcards have a configuration in which a base material is bonded by bonding via an adhesive layer, and the cost is inevitably increased due to its structure. Further, in these postcards, it is necessary to press the other base material after the information is written on one side of the base material, and the information is always written first.

  Japanese Patent Laid-Open No. 9-216481 (Patent Document 3) discloses a multilayer postcard having a self-coloring pressure-sensitive recording layer and capable of pressure-sensitive printing from the upper side of the concealing layer. This multilayer postcard can record information on the pressure-sensitive recording layer below the concealment layer by printing from the upper side of the concealment layer by a pressure-sensitive method using a printer such as an impact printer. However, in such a multi-layer postcard printed by the pressure-sensitive method, the print mark remains on the upper side or the back side of the postcard, and the confidentiality of the information is low.

  For this reason, higher confidentiality of information is required. For example, concealment postcards that can be printed by a thermal method provided with a thermal recording layer have been developed. For example, Japanese Unexamined Patent Application Publication No. 2007-230098 (Patent Document 4) discloses a multilayer postcard including a first base material, a thermal recording layer, a pseudo adhesive layer, and a second base material having a concealing region in this order. The concealment area may be a layer that does not transmit light over the entire surface (that is, a solid surface), and a plurality of patterns having a predetermined shape (for example, strips, meshes, zigzag, spots, characters, background patterns, etc. A layer that does not transmit light partially. Note that the concealment region can be formed by a normal printing method such as offset printing, gravure printing, flexographic printing, or the like. Since such a multi-layer postcard includes a heat-sensitive recording layer, information can be written in the heat-sensitive recording layer on the lower side from the upper side of the concealment region by a heat-sensitive method.

Similarly, International Publication No. 2006/070759 (Patent Document 5) discloses a thermal recording multiplex sheet and a method for producing the same. The heat-sensitive recording multiple sheet disclosed in Patent Document 5 includes a base material having a heat-sensitive recording layer, and further, a light-transmitting base material is pasted on the heat-sensitive recording layer. The information base has an information disclosure part and an information non-disclosure part, and a pattern corresponding to the information non-disclosure part has a pattern of a predetermined shape (for example, a band shape, a mesh shape, a staggered shape, a spot shape, a character , A ground pattern or the like) is provided. With such a structure, the disclosed information and the non-disclosure information can be thermally recorded at the same time, thereby improving information confidentiality, increasing the productivity of the laminated sheet, and reducing the manufacturing cost of the laminated sheet.
JP-A 64-16691 JP-A-2-289393 JP 9-216481 A Japanese Patent Laid-Open No. 2007-230098 International Publication No. 2006/070759 Pamphlet

  When printing from the upper side of a pressure-sensitive laminated sheet having a hiding layer, information can be written on the lower layer of the hiding layer, but the print marks remain clearly on the sheet, and the confidentiality of the information is considerably low . In addition, in the conventional laminated sheet using a heat-sensitive method having a concealing layer, heat is applied when printing information, so the surface state of the concealing layer changes chemically or physically, and the print marks become clear. There is a risk that there is a high possibility that information is leaked from the print marks. Such a phenomenon is prominent when the concealing layer is a solid print layer of dark color (for example, black, dark blue, ultramarine blue, green, brown, etc.). In the case of a solid print concealment layer, the print location may be visible when it is held over light. Even when the concealing layer is formed in a pattern having a predetermined shape, printing marks are often left in the same manner due to the influence of heat. Also, no matter how complicated the concealment pattern is, it is difficult to conceal continuous lines such as ruled lines. Furthermore, in the conventional concealment laminated sheet using the heat sensitive method, information may be transferred to the back side of the concealed part due to the influence of heat.

  Then, in view of the problems of the prior art, the present inventors have aimed to provide a laminated sheet having a concealing portion with improved information confidentiality.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have a white shielding layer, a character background pattern layer, a camouflage on at least a part of a heat-sensitive sheet and a transparent or translucent sheet bonded through a pseudo adhesive layer. It has been found that a laminated sheet having a concealed portion with excellent information confidentiality can be obtained by arranging the tint block layer and the resin layer in an overlapping manner, and the present invention has been completed.

  That is, this invention relates to the following laminated sheets.

  A laminated sheet comprising a heat-sensitive sheet and a transparent or translucent sheet formed on the heat-sensitive sheet, wherein a white shielding layer is formed on at least a part of the transparent or translucent sheet opposite to the heat-sensitive sheet; A laminated sheet having a concealing portion including a character background pattern layer, a camouflage background pattern layer, and a resin layer.

  In the above laminated sheet, it is preferable that the concealing portion is formed by overlapping the white shielding layer, the character background pattern layer, the camouflage background pattern layer, and the resin layer in this order.

  In the laminated sheet, it is preferable that the heat-sensitive sheet and the transparent or translucent sheet are pseudo-bonded.

  In the above laminated sheet, the light transmittance of the white shielding layer is preferably 80% or less of the light transmittance of the transparent or translucent sheet.

  In the above laminated sheet, the light transmittance of the white shielding layer is preferably 60% or less of the light transmittance of the transparent or translucent sheet.

  In the above laminated sheet, the ratio of the character background pattern in the character background pattern layer is preferably 30% or more with respect to the total area of the character background pattern layer.

  In the above laminated sheet, it is preferable that the ratio of the camouflage background pattern in the camouflage background pattern layer is 30% or more with respect to the total area of the camouflage background pattern layer.

  In the above laminated sheet, it is preferable that the ratio of the camouflage background pattern in the camouflage background pattern layer is 50 to 60% with respect to the total area of the camouflage background pattern layer.

  In the above laminated sheet, it is preferable that the camouflage tint block in the camouflage tint layer includes a straight line.

  In the laminated sheet, the resin layer is preferably a transparent resin layer made of an ultraviolet curable resin.

  In the laminated sheet, the resin layer preferably has a thickness of 1 μm or less.

  In the laminated sheet, it is preferable that information is described on the heat sensitive sheet from the upper side of the concealed portion by a heat sensitive method.

  The laminated sheet is preferably used as a postcard.

  The laminated sheet of the present invention includes a heat-sensitive sheet and a transparent or translucent sheet formed thereon, and at least a part of the transparent or translucent sheet opposite to the heat-sensitive sheet has a white shielding layer and a character background pattern. A concealing portion including a layer, a camouflage tint block layer, and a resin layer is disposed. In the present invention, the white shielding layer, the character background pattern layer, the camouflage background pattern layer, and the resin layer are collectively referred to as a “hiding portion”. In the present invention, it is desirable that the outermost layer of the concealing portion is a resin layer.

  Since the laminated sheet of the present invention has such a structure, various information can be described on the heat-sensitive sheet on the lower side of the concealed part from the upper side of the concealed part by the thermal method.

  The white shielding layer shields the description information and can effectively shield the description information even when the light is watermarked.

  The character copy-forgery-inhibited pattern layer can make it difficult to interpret information described below the concealment portion, particularly character information. In that case, it is effective to make the character size of the character background pattern layer slightly larger than the character size of the written information.

  The camouflaged tint layer can camouflage information described below the concealed portion, making it difficult to interpret. In addition, since the camouflaged tint block layer includes a blank (outlined) portion, it is possible to effectively camouflage the description information even when the light is watermarked. Further, when printing is performed by the thermal method, the camouflaged tint block layer includes the blank portion as described above, and thus has an advantage that the print mark is interrupted and cannot be completely read. Similarly, complete transfer to a transparent or translucent sheet by heat can also be suppressed.

  Since the resin layer can chemically and physically protect the heat-sensitive recording layer, information confidentiality can be further enhanced. In the case of the thermal method, the frictional resistance of the thermal head can be reduced, thereby improving the scanning performance of the head. Moreover, the resin layer can prevent adhesion of the character background pattern and the camouflage background pattern to the thermal head.

  Therefore, the laminated sheet of the present invention can dramatically improve information confidentiality by including all of the concealing portion, that is, the white shielding layer, the character background pattern layer, the camouflage background pattern layer, and the resin layer. When the laminated sheet of the present invention is used as, for example, a postcard, a concealing postcard with high information confidentiality can be provided at a low cost, which is very economical. Moreover, the manufacturing process is not complicated and the productivity is high.

  According to the laminated sheet of the present invention, information can be written in a heat sensitive manner from the upper side of the sheet, which is very simple. Moreover, no print marks are formed by heat on the upper side of the concealed part and on the back side of the laminated sheet, and the internal written information cannot be read. Moreover, even when the light is watermarked, it is impossible to read the internal information. Furthermore, there is no print mark on the back side of the peeled sheet. Further, the written information is not transferred to the back side of the peeled sheet. Therefore, the present invention can provide very excellent information confidentiality.

  The present invention relates to a laminated sheet comprising a transparent or translucent sheet and a heat-sensitive sheet, and the present invention relates to a white shielding layer, a character background pattern layer, a camouflage background pattern layer, and a resin layer on at least a part of the transparent or translucent sheet. It is characterized by arranging. In the present invention, it is desirable that the white shielding layer is the lowermost layer and the resin layer is the uppermost layer. In the present invention, the white shielding layer, the character background pattern layer, the camouflage background pattern layer, and the resin layer are collectively referred to as a “hiding portion”, and information is transferred from the upper side of the hiding portion to the heat sensitive sheet below the hiding portion by a thermal method. Can be described. Moreover, a transparent or semi-transparent sheet | seat and a heat sensitive sheet can be bonded together in the state which can be re-peeled through a pseudo adhesion layer. Only when the transparent or translucent sheet is turned together with the concealment portion, the information described below the concealment portion becomes clear. In the present invention, it is desirable that re-sticking is impossible.

  FIG. 1 shows a concealment postcard which is a preferred embodiment of the laminated sheet of the present invention, and schematically shows a cross section in the longitudinal direction (longitudinal direction). According to this embodiment, the transparent or translucent sheet (1) and the heat-sensitive sheet (2) are bonded together in a pseudo-adhesive state, and at least part of the sheet (1) is covered with white as a concealing part. The layer (3), the character background pattern layer (4), the camouflage background pattern layer (5), and the resin layer (6) are arranged in this order. As another embodiment of the present invention, the order of the character background pattern layer (4) and the camouflage background pattern layer (5) may be reversed, that is, the character background pattern layer may be disposed on the camouflage background pattern layer. A plurality of character background patterns and camouflage background patterns may be included. Hereinafter, each layer will be described in detail.

Transparent or translucent sheet The transparent or translucent sheet that can be used in the present invention is not particularly limited as long as it can transmit light and does not completely block light. For example, glassine paper, Examples include cellophane paper, imitation paper, and tracing paper.

  The transparent or translucent sheet that can be used in the present invention usually has a light transmittance of 10 to 100%, preferably 20 to 30%, more preferably 22 to 26%. When the light transmittance is within the above range, the light is not completely blocked, and the information printed on the lower side of the transparent or translucent sheet can be read from the upper side in the portion without the hidden portion.

  The thickness of the transparent or translucent sheet that can be used in the present invention is usually 20 to 50 μm, preferably 25 to 35 μm. If the thickness exceeds 50 μm, there is a risk of problems such as difficulty in describing information by a thermal method. Further, if the thickness is less than 20 μm, there is a risk of problems such as increased difficulty of work in the pseudo-adhesion process, the printing process, and the like.

  Moreover, in this invention, you may describe various information in parts other than the concealment part of a transparent / translucent sheet | seat. For example, as shown in FIG. 2, when the laminated sheet of the present invention is used as a postcard, a stamp pasting position, a postal code description column, and the like may be described on the transparent / translucent sheet.

White shielding layer The transparent or translucent sheet has a white shielding layer on at least a part of one surface thereof, that is, the surface opposite to the pseudo-adhesion surface. The white shielding layer is intended to suppress light transmission, and can make it difficult to read information concealed when the concealing laminated sheet is held over light. Therefore, the white shielding layer desirably has a light transmittance of 80% or less, preferably 70% or less, more preferably 60% or less of the light transmittance of the transparent or translucent sheet. When the light transmittance of the white shielding layer exceeds 80% of the light transmittance of the transparent or translucent sheet, the light is transmitted too much, and the information concealed when the concealed laminated sheet is held over light is easy to read. There is a possibility.

  The white shielding layer can be formed by printing, and the printing method is not particularly limited, and for example, various conventionally known printing methods are possible. Offset printing, gravure printing, and flexographic printing are preferable, and offset printing is particularly preferable. In the present invention, the white shielding layer is a white solid printing layer having a reflectance of 90% or more, preferably 95% or more, more preferably 98% or more. In the present invention, solid printing means full surface printing. If the reflectance is less than 90%, the coloring of the heat-sensitive sheet cannot be blocked, and there is a possibility that problems such as being visible from the surface may occur.

  The ink that can form the white shielding layer is not particularly limited as long as it is a white ink. For example, white UV-curing ink (for example, T & K's modified UV161 concrete white, DIC's Dicure New BF -Z white, Inktec UV SG white, etc.).

  The thickness of the white shielding layer is 0.5 to 4.0 μm, preferably 1.0 to 3.0 μm, more preferably 1.5 to 2.5 μm. If the thickness is outside the above range, it is difficult to control light transmission. There is a risk of becoming.

  The white shielding layer may be formed on the entire surface of the transparent or translucent sheet as necessary. In a postcard which is a preferred embodiment of the present invention, there is always a portion including information to be disclosed such as a destination address, and therefore the white shielding layer is usually a portion other than those. Therefore, it is preferable to arrange the white shielding layer in a portion where information to be concealed will be described.

Character background pattern layer The character background pattern layer is provided on the upper side of the white shielding layer for the purpose of making it difficult to easily read and guess information written on the lower side of the concealed portion, in particular, from the upper side of the character information. preferable.

  The character copy-forgery-inhibited pattern layer can be formed by ordinary printing, and the printing method is not particularly limited. For example, various conventionally known printing methods are possible. Offset printing, gravure printing, and flexographic printing are preferable, and offset printing is particularly preferable.

  There are no particular limitations on the characters included in the character copy-forgery-inhibited pattern layer, but it is preferable to use characters (fonts) of the same type as the concealment information in order to make it difficult to read the concealment information. For example, when the concealment information is written in Mincho style, it is preferable to form the character copy-forgery-inhibited pattern layer with Mincho style letters. When the concealment information includes numbers, the character copy-forgery-inhibited pattern layer preferably includes numbers. In the present invention, all characters of all kinds can be used as the characters capable of forming the character background pattern layer, and any number may be included. It is preferable to use a combination of characters and numbers of a plurality of types of fonts because it becomes more difficult to read the concealment information. By including the reversed characters in the character background pattern layer and printing, it is possible to make the concealment information more difficult to read.

  If the size of the characters forming the character background pattern layer is smaller than the characters of the concealment information, the concealment information tends to be easily understood. Therefore, in order to make the concealment information more difficult to interpret, the size (size) of the characters printed as the character copy-forgery-inhibited pattern layer is 0.5 to 5.0 points, preferably 0.5 to It is desirable to increase it by 1.0 point. It is more preferable to use a combination of characters of different sizes because it becomes more difficult to interpret the concealment information.

  It is preferable that the density of characters in the character background pattern layer is 1.5 to 3 times, preferably 1.5 to 2 times the character density of the concealment information, since it becomes more difficult to read the concealment information.

  The ratio of the character background pattern in the character background pattern layer is 30% or more, preferably 40 to 70%, more preferably 50 to 60% with respect to the entire area of the character background pattern layer. Accordingly, the blank space (white area) without the character background pattern in the character background pattern layer is less than 70%, preferably 30 to 60%, more preferably 40 to 50% with respect to the entire area of the character background pattern layer.

  Moreover, in the character background pattern layer, it is preferable that printing of the character angle is arbitrarily shifted by 1 to 90 °, preferably 1 to 30 ° with respect to the character of the concealment information, so that the concealment information becomes more difficult to read. . Moreover, you may print the angle of a character at all angles at random.

  Furthermore, by printing the characters forming the character background pattern layer in two or more colors (for example, black and blue colors such as blue, dark blue, group blue, deep blue, dark blue, etc.) Interpretation can be made more difficult, which is preferable. More preferably, the character background pattern forming the character background pattern layer includes a color different from the color of the camouflage background pattern forming the camouflage background pattern layer described below.

  The thickness of the character background pattern layer is usually 0.7 to 1.5 μm, preferably 0.7 to 1.2 μm, more preferably 0.8 to 1.0 μm, and the thickness of the character background pattern layer is less than 0.7 μm. If it exists, there is a risk that the information described on the heat-sensitive sheet cannot be concealed, and if the thickness of the text tint layer exceeds 1.5 μm, the ink that forms the text tint layer becomes insufficiently cured and soiled. There is a risk of causing.

  FIG. 3 shows an example of a character copy-forgery-inhibited pattern of a preferred embodiment of the present invention, but the character copy-forgery-inhibited pattern usable in the present invention is not limited to this.

Camouflage Background Pattern In the present invention, the camouflage background pattern layer means a layer including an arbitrary camouflage background pattern that can be formed by normal printing, and can be provided on the upper side, the lower side, or both of the character background pattern layer.

  The camouflage tint block layer can be formed by printing, and the printing method is not particularly limited. For example, various conventionally known printing methods are possible. Offset printing, gravure printing, and flexographic printing are preferable, and offset printing is particularly preferable.

  The camouflage pattern is not particularly limited as long as it has a blank space (for example, a mesh pattern, a checkered pattern, a mosaic pattern, a triangle pattern, a hexagon pattern, a random pattern, etc.). From the viewpoint of performance, a mesh camouflage pattern is preferable. FIG. 4 shows an example of a camouflage background pattern (a mesh background pattern) according to a preferred embodiment of the present invention.

  Since the camouflaged background pattern has a blank space, even if printing is performed from the upper side by the thermal method, the print mark becomes partial, and the information confidentiality is much higher than the concealment by the dark solid printing. In addition, since the camouflaged background pattern may have irregular margins, the light transmission is irregular, which can further enhance the confidentiality of information.

  The ratio of the camouflage background pattern in the camouflage background pattern layer (that is, the ratio of the background pattern excluding the blank space) is 30% or more, preferably 40 to 70%, more preferably 50 to 60% with respect to the total area of the camouflage background pattern layer. is there. Therefore, the blank space (outlined space) without the camouflage background pattern in the camouflage background pattern layer is less than 70, preferably 30 to 60%, more preferably 40 to 50% with respect to the total area of the camouflage background pattern layer.

  The camouflage pattern layer further includes a straight camouflage pattern, which makes it difficult to interpret continuous line patterns such as ruled lines contained in concealment information, and provides better information confidentiality than before. Can do. 5 shows a camouflage tint block including a straight line pattern in addition to the camouflage tint block of FIG. 4, and FIG. 6 illustrates only the camouflage tint block consisting of straight lines that can be included in the camouflage tint block layer.

  In a preferred embodiment of the present invention, as shown in FIGS. 4 and 5, the camouflaged tint layer is particularly preferably a mesh.

  The mesh size of the mesh camouflage pattern depends on the size of the print character of the concealment information. For example, if the concealment information print character is a 9-point half-width number, the width of the number is usually 1.2 to 1.4 mm, although it depends on the type of font used, a continuous 4-digit number. The total width is about 5 to 6.5 mm, and the total width is 7.7 to 8.4 mm for a five-digit number. Therefore, when the mesh size of the mesh pattern (that is, the maximum margin width) is set to 5 mm, it is difficult to specify the number of digits in the case of a 4-digit or 5-digit number. Note that 4-digit or 5-digit 9-point half-width numbers are very often used for billing, etc., making it difficult to interpret these numbers from the viewpoint of information security management. It is beneficial.

  The color of the camouflage tint block forming the camouflage tint block layer is preferably black, but more preferably a color different from the color of the character tint block.

  The thickness of the camouflage background pattern layer is usually 0.7 to 1.5 μm, preferably 0.7 to 1.2 μm, more preferably 0.8 to 1.0 μm, and the thickness of the camouflage background pattern layer is less than 0.7 μm. If it exists, there is a possibility that the information described on the heat-sensitive sheet cannot be concealed. If the thickness of the camouflage tint layer exceeds 1.5 μm, the ink that forms the camouflage tint layer becomes insufficiently cured, causing stains. There is a risk of causing.

It is desirable to provide a resin layer as the uppermost layer of the concealing portion for the purpose of preventing chemical and physical changes on the sheet surface that may be caused by the influence of heat when concealing information is printed by the resin layer thermal method. By providing the resin layer, after printing by the heat sensitive method, the print mark due to the influence of heat does not remain on the surface of the concealed portion, and the confidentiality of information is dramatically increased. Further, when printing with a thermal head using a thermal head, by providing such a resin layer, not only the scanning performance of the thermal head (that is, head matching) can be improved, but also the above-mentioned character background pattern and camouflage. It is possible to prevent the ink forming the background pattern from adhering to the thermal head and degrading the printing performance.

  The resin that can form the resin layer is not particularly limited as long as it is a hard resin that does not easily deform even when heat is applied. For example, an ultraviolet curable resin known in the art, such as a urethane-acrylic copolymer. An ultraviolet curable resin etc. are mentioned. Among these, it is particularly preferable to use an ultraviolet curable OP varnish. Commercially available products such as Nippon Kayaku's UFR-11D, DIC's WLOP varnish WS, and T & K's release OP varnish UP200 may be used as the OP varnish.

  Although there is no limitation in particular in the color of a resin layer, it is especially preferable that it is transparent after hardening. Further, if necessary, a pigment such as a flaky pearl pigment may be added to the resin layer to suppress light transmission and further improve the concealing property. However, in this case, if dark pigments such as black are used, the concealment information may be readable from the sheet surface due to light reflection, so it is not appropriate to use dark pigments such as black. It is desirable to use a white pigment.

  The thickness of the resin layer is 1 μm or less, preferably 0.3 to 0.8 μm, more preferably 0.3 to 0.5 μm. If the thickness of the resin layer exceeds 1 μm, the amount of heat reaching the heat-sensitive sheet below the transparent or semi-transparent sheet decreases, and there is a risk of problems such as poor color development of the heat-sensitive sheet.

The thermal sheet that can be used in the heat-sensitive sheet present invention is not particularly limited and may be conventionally known heat-sensitive sheet.

  The heat-sensitive sheet is usually a sheet-like material having a base material and a heat-sensitive recording layer formed on one surface thereof. For example, the heat-sensitive sheet disclosed in Patent Document 4 (Japanese Patent Laid-Open No. 2007-230098) is used. be able to.

The material of the base material of the heat-sensitive sheet is not particularly limited, and materials generally used for multilayer postcards such as paper and various synthetic resins can be used.

  As the base material of the heat-sensitive sheet, a material that does not transmit light is preferable because the confidentiality of information recorded on the heat-sensitive recording layer is excellent.

  Examples of the base material that does not transmit light include a paper base material mainly composed of pulp, a base material mainly composed of synthetic resin (film base material); and a colorant such as a white inorganic pigment contained in these base materials. And the like.

  Examples of the paper base mainly composed of pulp include high-quality paper, recycled paper, light shielding paper (for example, a multi-layered paper sheet in which the intermediate layer is a highly opaque unbleached pulp layer), and glassine paper.

  As film base materials, polyethylene terephthalate film, polybutylene terephthalate film, polyethylene film, polypropylene film, polycarbonate film, polyurethane film, polyimide film, polyvinyl chloride film, cellophane, cellulose triacetate film, cellulose diacetate film, tetrafluoroethylene Examples thereof include a film, a polyvinylidene fluoride film, and a polymonochlorotrifluoroethylene film.

  These substrates are appropriately used as necessary.

  When the pseudo adhesive layer is formed by a wet lamination method, the base of the heat sensitive sheet preferably has air permeability, and is particularly preferably paper.

  The thickness of the base material of the heat-sensitive sheet is not particularly limited, and may be set as appropriate in consideration of protection of the heat-sensitive recording layer, information confidentiality, suitability for adhesion processing, handleability, and the like.

For example, 80 to 300 g / m ² is preferable in consideration of suitability for adhesion processing and handling properties when used as postcards such as postcards.

Moreover, when the ease of peeling at the time of peeling a heat sensitive sheet and a transparent or translucent sheet is considered, it is preferable that a basic weight is 100 g / m < ² > or more, and 120-250 g / m < ² > is more preferable.

Heat-sensitive recording layer As the heat-sensitive recording layer, those conventionally proposed can be used. Examples of the heat-sensitive recording layer include a layer containing a reactive dye (dye precursor) and a developer. In such a layer, the reactive dye and the developer react with heat to develop color.

  The heat-sensitive recording layer may be a single layer containing a reactive dye and a developer, a layer containing a reactive dye and no developer, a layer containing a developer and a reactive dye. It may be a multilayer of two or more layers including a layer not containing. A single layer is preferable because of excellent reactivity and thermal response.

  Various known dyes and reactive dyes can be used.

  Specific combinations of reactive dyes and developers include leuco compounds (leuco dyes) and electron-accepting substances, imino compounds and isocyanate compounds, long-chain fatty acid iron salts and polyhydric phenols. And the like.

  Among these, a combination of a leuco compound and an electron-accepting substance is preferable because it has good thermal responsiveness, a high color density, and is relatively stable. A combination of an imino compound and an isocyanate compound is preferable because its color development is hardly affected by the surfactant and is excellent in storage stability.

  Specific examples of these reactive dyes and developers are shown below.

  Examples of the leuco compound used as the reactive dye include triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, spiropyran-based and indolinophthalide-based compounds. Specifically, 3,3-bis (p-dimethylaminophenyl) -phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3,3-bis (p-dimethylamino) Phenyl) -6-diethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide, 3,3-bis (p-dibutylaminophenyl) phthalide, 3-cyclohexylamino-6-chlorofluorane 3-dimethylamino-5,7-dimethylfluorane, 3-N-methyl-N-isobutyl-6-methyl-7-anilinofluorane, 3-N-ethyl-N-isoamyl-6-methyl-7 -Anilinofluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7, Benzfluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3- (N-ethyl-Np-tolyl) -6-methyl-7-anilinofluorane, 3- (Np -Tolyl-N-ethylamino) -6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2- {N-3'-trifluoromethylphenyl) amino} -6-diethylaminofluorane, 2- {3,6-bis (diethylamino) -9- (o-chloroanilino) xanthylbenzoate lactam}, 3-diethylamino-6-methyl-7- (m-trichloromethylanilino) Fluorane, 3-diethylamino-7- (o-chloroanilino) fluorane, 3-dibutylamino-7- (o-chloroanilino) fluorane, 3-N-methyl N-amylamino-6-methyl-7-anilinofluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluor Oran, 3-diethylamino-6-methyl-7- (2 ′, 4′-dimethylanilino) fluorane, 3- (N 2, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino) Fluorane, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrospirane, 6'-bromo-3'-methoxy-benzoindolino-pyrospirane, 3- (2'-hydroxy-4'-dimethyl) Aminophenyl) -3- (2′-methoxy-5′-chlorophenyl) phthalide, 3- (2′-hydroxy-4′-dimethyl) Minophenyl) -3- (2′-methoxy-5′-nitrophenyl) phthalide, 3- (2′-hydroxy-4′-diethylaminophenyl) -3- (2′-methoxy-5′-methylphenyl) phthalide, 3- (2′-methoxy-4′-dimethylaminophenyl) -3- (2′-hydroxy-4′-chloro-5′-methylphenyl) phthalide, 3-morpholino-7- (N-propyl-trifluoro) Methylanilino) fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7- (N-benzyl-trifluoromethylanilino) fluorane, 3-pyrrolidino-7- ( Di-p-chlorophenyl) methylaminofluorane, 3-diethylamino-5-chloro-7- (α-phenylethylamino) fur Oran, 3- (N-ethyl-p-toluidino) -7- (α-phenylethylamino) fluorane, 3-diethylamino-7- (o-methoxycarbonylphenylamino) fluorane, 3-diethylamino-5-methyl-7 -(Α-phenylethylamino) fluorane, 3-diethylamino-7-piperidinofluorane, 2-chloro-3- (N-methyltoluidino) -7- (pn-butylanilino) fluorane, 3- (N- Methyl-N-isopropylamino) -6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3,6-bis (dimethylamino) fluorene spiro (9,3 ') -6'-dimethylaminophthalide, 3- (N-benzyl-N-cyclohexylamino) -5,6-benzo-7-α Naphthylamino-4′-bromofluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3-N-ethyl-N- (2-ethoxypropyl) amino-6-methyl-7-anilinofluor Oran, 3-N-ethyl-N-tetrahydrofurfurylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-mesitidino-4 ′, 5′-benzofluorane and the like It is done. These leuco compounds may be blended singly or in combination of two or more.

  The electron-accepting substance that contacts with the leuco compound and develops color is not particularly limited, and examples thereof include phenolic compounds, thiophenolic compounds, thiourea derivatives, organic acids and metal salts thereof.

  Specifically, 4-tert-butylphenol, 4-acetylphenol, 4-tert-octylphenol, 4,4′-sec-butylidene diphenol, 4-phenylphenol, 4,4′-dihydroxydiphenylmethane, 4,4′- Isopropylidene diphenol, 4,4′-cyclohexylidene diphenol, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 4,4′-dihydroxydiphenyl sulfide, 4,4′-thiobis (3- Methyl-6-tert-butylphenol), 4,4′-dihydroxydiphenylsulfone, 2,4′-dihydroxydiphenylsulfone, 4-hydroxy-4′-isopropoxydiphenylsulfone, and bis (3-allyl-4-hydroxyphenyl) ) Sulfone, bis (p Phenolic compounds such as hydroxyphenyl) butyl acetate, methyl bis (p-hydroxyphenyl) acetate, 4-hydroxybenzophenone, dimethyl 4-hydroxyphthalate, methyl 4-hydroxybenzoate, 4-hydroxybenzoate propyl, 4- Phenolic compounds such as hydroxybenzoic acid-sec-butyl, phenyl 4-hydroxybenzoate, benzyl 4-hydroxybenzoate, tolyl 4-hydroxybenzoate, chlorophenyl 4-hydroxybenzoate, 4,4′-dihydroxydiphenyl ether, or , Benzoic acid, p-tert-butylbenzoic acid, trichlorobenzoic acid, terephthalic acid, salicylic acid, 3-tert-butylsalicylic acid, 3-isopropylsalicylic acid, 3-benzylsalicylic acid, 3- (α-methylbenzyl) Organic acidity such as aromatic carboxylic acids such as salicylic acid and 3,5-di-tert-butylsalicylic acid, and salts of these phenolic compounds and aromatic carboxylic acids with polyvalent metals such as zinc, magnesium, aluminum and calcium Substances, Np-toluenesulfonyl-N′-3- (p-toluenesulfonyloxy) phenylurea, N- (p-toluenesulfonyl) -N ′-(p-butoxycarbonyl) urea, Np-tolylsulfonyl And urea compounds such as -N'-phenylurea.

  These electron accepting substances may be blended alone or in combination of two or more.

An imino compound is a compound having at least one imino group (═NH).
As the imino compound used as the reactive dye, for example, a room temperature solid colorless or light-colored compound represented by the following general formula (I) may be mentioned.

  [Wherein X represents an aromatic compound residue capable of forming a conjugated system with adjacent C═N. ]

  Specifically, as the imino compound, 3-iminoisoindoline-1-one, 3-imino-4,5,6,7-tetrachloroisoindoline-1-one, 3-imino-4,5,6, 7-tetrabromoisoindoline-1-one, 3-imino-4,5,6,7-tetrafluoroisoindoline-1-one, 3-imino-5,6-dichloroisoindoline-1-one, 3- Imino-4,5,7-trichloro-6-methoxy-isoindoline-1-one, 3-imino-4,5,7-trichloro-6-methylmercapto-isoindoline-1-one, 3-imino-6 -Nitroisoindoline-1-one, 3-imino-isoindoline-1-spiro-dioxolane, 1,1-dimethoxy-3-imino-isoindoline, 1,1-diethoxy-3-imino-4 5,6,7-tetrachloroisoindoline, 1-ethoxy-3-imino-isoindoline, 1,3-diiminoisoindoline, 1,3-diimino-4,5,6,7-tetrachloroisoindoline, 1,3-diimino-6-methoxyisoindoline, 1,3-diimino-6-cyanoisoindoline, 1,3-diimino-4,7-dithia-5,5,6,6-tetrahydroisoindoline, 7- Amino-2,3-dimethyl-5-oxopyrrolo [3,4b] pyrazine, 7-amino-2,3-diphenyl-5-oxopyrrolo [3,4b] pyrazine, 1-iminonaphthalimide, 1-iminodiphenimide, 1-phenylimino-3-iminoisoindoline, 1- (3′-chlorophenylimino) -3-iminoisoindoline, 1- (2 ′, 5′- Chlorophenylimino) -3-iminoisoindoline, 1- (2 ′, 4 ′, 5′-trichlorophenylimino) -3-iminoisoindoline, 1- (2′-cyano-4′-nitrophenylimino) -3 -Iminoisoindoline, 1- (2'-chloro-5'-cyanophenylimino) -3-iminoisoindoline, 1- (2 ', 6'-dichloro-4'-nitrophenylimino) -3-iminoiso Indoline, 1- (2 ′, 5′-dimethoxyphenylimino) -3-iminoisoindoline, 1- (2 ′, 5′-diethoxyphenylimino) -3-iminoisoindoline, 1- (2′-methyl) -4′-nitrophenylimino) -3-iminoisoindoline, 1- (5′-chloro-2′-phenoxyphenylimino) -3-iminoisoindoline, 1 -(4'-N, N-dimethylaminophenylimino) -3-iminoisoindoline, 1- (3'-N, N-dimethylamino-4'-methoxyphenylimino) -3-iminoisoindoline, 1- (2′-methoxy-5′-N-phenylcarbamoylphenylimino) -3-iminoisoindoline, 1- (2′-chloro-5′-trifluoromethylphenylimino) -3-iminoisoindoline, 1- ( 5 ′, 6′-dichlorobenzothiazolyl-2′-imino) -3-iminoisoindoline, 1- (6′-methylbenzothiazolyl-2′-imino) -3-iminoisoindoline, 1- (4′-phenylaminophenylimino) -3-iminoisoindoline, 1- (p-phenylazophenylimino) -3-iminoisoindoline, 1- (naphthi -1′-imino) -3-iminoisoindoline, 1- (anthraquinone-1′-imino) -3-iminoisoindoline, 1- (5′-chloroanthraquinone-1′-imino) -3-imino Isoindoline, 1- (N-ethylcarbazolyl-3′-imino) -3-iminoisoindoline, 1- (naphthoquinone-1′-imino) -3-iminoisoindoline, 1- (pyridyl-4′- Imino) -3-iminoisoindoline, 1- (benzimidazolone-6′-imino) -3-iminoisoindoline, 1- (1′-methylbenzimidazolone-6′-imino) -3-iminoisoindoline 1- (7′-chlorobenzimidazolone-5′-imino) -3-iminoisoindoline, 1- (benzimidazolyl-2′-imino) -3-iminoisoin Phosphorus, 1- (benzimidazolyl-2′-imino) -3-imino-4,5,6,7-tetrachloroisoindoline, 1- (2 ′, 4′-dinitrophenylhydrazone) -3-iminoisoindoline 1- (indazolyl-3′-imino) -3-iminoisoindoline, 1- (indazolyl-3′-imino) -3-imino-4,5,6,7-tetrabromoisoindoline, 1- (indazolyl) -3'-imino) -3-imino-4,5,6,7-tetrafluoroisoindoline, 1- (benzimidazolyl-2'-imino) -3-imino-4,7-dithiatetrahydroisoindoline, 1- (4 ′, 5′-dicyanoimidazolyl-2′-imino) -3-imino-5,6-dimethyl-4,7-pyradiisoindoline, 1- (cyanobenzoylmethyle ) -3-iminoisoindoline, 1- (cyanocarbonamidomethylene) -3-iminoisoindoline, 1- (cyanocarbomethoxymethylene) -3-iminoisoindoline, 1- (cyanocarboethoxymethylene) -3- Iminoisoindoline, 1- (cyano-N-phenylcarbamoylmethylene) -3-iminoisoindoline, 1- [cyano-N- (3′-methylphenyl) -carbamoylmethylene] -3-iminoisoindoline, 1- [ Cyano-N- (4′-chlorophenyl) -carbamoylmethylene] -3-iminoisoindoline, 1- [cyano-N- (4′-methoxyphenyl) -carbamoylmethylene] -3-iminoisoindoline, 1- [cyano -N- (3'-chloro-4'-methylphenyl) -carbamoylmethylene]- -Iminoisoindoline, 1- (cyano-p-nitrophenylmethylene) -3-iminoisoindoline, 1- (dicyanomethylene) -3-iminoisoindoline, 1- [cyano-1 ', 2', 4'- Triazolyl- (3 ′)-carbamoylmethylene] -3-iminoisoindoline, 1- [cyanothiazoyl- (2 ′)-carbamoylmethylene] -3-iminoisoindoline, 1- [cyanobenzimidazolyl- (2 ′)-carbamoyl Methylene] -3-iminoisoindoline, 1- [cyanobenzothiazolyl- (2 ′)-carbamoylmethylene] -3-iminoisoindoline, 1- [cyanobenzimidazolyl- (2 ′)-methylene] -3- Iminoisoindoline, 1- [cyanobenzimidazolyl- (2 ′)-methylene] -3-imino- , 5,6,7-tetrachloroisoindoline, 1-[(cyanobenzimidazolyl-2 ')-methylene] -3-imino-5-methoxyisoindoline, 1-[(cyanobenzimidazolyl-2')-methylene ] -3-Imino-6-chloroisoindoline, 1-[(1′-phenyl-3′-methyl-5-oxo) -pyrazolidene-4 ′]-3-iminoisoindoline, 1-[(cyanobenzimidazolyl) -2 ')-methylene] -3-imino-4,7-dithiatetrahydroisoindoline, 1-[(cyanobenzimidazolyl-2')-methylene] -3-imino-5,6-dimethyl-4,7 -Pyradiisoindoline, 1-[(1'-methyl-3'-n-butyl) -barbituric acid-5 ']-3-iminoisoindoline, 3-imino-1-sulfobenzoate Fragrance imide, 3-imino-1-sulfo-6-chlorobenzoic acid imide, 3-imino-1-sulfo-5,6-dichlorobenzoic imide, 3-imino-1-sulfo-4,5,6 7-tetrachlorobenzoic acid imide, 3-imino-1-sulfo-4,5,6,7-tetrabromobenzoic acid imide, 3-imino-1-sulfo-4,5,6,7-tetrafluorobenzoic acid imide 3-imino-1-sulfo-6-nitrobenzoimide, 3-imino-1-sulfo-6-methoxybenzoimide, 3-imino-1-sulfo-4,5,7-trichloro-6-methyl Mercaptobenzoic acid imide, 3-imino-1-sulfonaphthoic acid imide, 3-imino-1-sulfo-5-bromonaphthoic acid imide, 3-imino-2-methyl-4,5,6,7-tetrachloroisoindoli 1-one and the like.

  Examples of the isocyanate compound that develops color upon contact with an imino compound include a room temperature solid colorless or light-colored aromatic isocyanate compound or a heterocyclic isocyanate compound.

  Specific examples of the isocyanate compound include 2,6-dichlorophenyl isocyanate, p-chlorophenyl isocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, and 1,3-dimethylbenzene-4. , 6-diisocyanate, 1,4-dimethylbenzene-2,5-diisocyanate, 1-methoxybenzene-2,4-diisocyanate, 1-methoxybenzene-2,5-diisocyanate, 1- Ethoxybenzene-2,4-diisocyanate, 2,5-dimethoxybenzene-1,4-diisocyanate, 2,5-diethoxybenzene-1,4-diisocyanate, 2,5-dibutoxybenzene 1,4-diisocyanate, azobenzene-4,4′-diisocyanate, diphenyl ether-4,4 ′ Diisocyanate, naphthalene-1,4-diisocyanate, naphthalene-1,5-diisocyanate, naphthalene-2,6-diisocyanate, naphthalene-2,7-diisocyanate, 3,3′-dimethyl -Biphenyl-4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenyldimethylmethane-4,4'-di Isocyanate, benzophenone-3,3′-diisocyanate, fluorene-2,7-diisocyanate, anthraquinone-2,6-diisocyanate, 9-ethylcarbazole-3,6-diisocyanate, bilen- 3,8-diisocyanate, naphthalene-1,3,7-triisocyanate, biphenyl-2,4,4 -Triisocyanate, 4,4 ', 4 "-Triisocyanato-2,5-dimethoxytriphenylamine, 4,4', 4" -Triisocyanatotriphenylamine, p-dimethylaminophenyl isocyanate , Tris (4-phenyl isocyanate) thiophosphate and the like.

  These isocyanate compounds may be used in the form of so-called block isocyanate, which is an addition compound with phenols, lanthanums, oximes, etc., if necessary. Diisocyanate dimer, for example, 1 -It may be used in the form of dimer of methylbenzene-2,4-diisocyanate and isocyanurate which is trimer, and can also be used as polyisocyanate adducted with various polyols It is.

  In the heat-sensitive recording layer, the amount of the reactive dye is preferably 10 to 50% by weight, more preferably 10 to 20% by weight, based on the total solid content of the heat-sensitive recording layer, considering color developability.

  In the heat-sensitive recording layer, the blending amount of the developer is preferably 100 to 700 parts by mass, more preferably 150 to 400 parts by mass with respect to 100 parts by mass of the reactive dye.

  The heat-sensitive recording layer preferably further contains a binder in addition to the reactive dye and the developer.

  Examples of the binder include polyvinyl alcohol and derivatives thereof, starch and derivatives thereof, cellulose derivatives such as hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylcellulose, and ethylcellulose, polyacrylic acid soda, polyvinylpyrrolidone, and acrylamide-acrylic acid ester copolymer. Water-soluble polymer materials such as acrylamide-acrylic acid ester-methacrylic acid ester copolymer, styrene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, casein, gelatin and derivatives thereof, and Polyvinyl acetate, polyurethane, polyacrylic acid, polyacrylic ester, vinyl chloride-vinyl acetate copolymer, polybutyl methacrylate, ethylene-vinyl acetate Emulsions and styrene polymers such as - butadiene copolymer, styrene - butadiene - such as latex of water-insoluble polymers such as acrylic copolymers and the like.

  In the thermosensitive recording layer, the blending amount of the binder is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, based on the total solid content of the thermosensitive recording layer.

  The heat-sensitive recording layer preferably further contains a sensitizer in order to adjust the color development sensitivity.

  As the sensitizer, a compound conventionally known as a sensitizer for a thermal recording material can be used. For example, a compound having a relatively low melting point (for example, about 80 to 150 ° C.), a reactive dye and An organic substance having compatibility with the developer (hereinafter referred to as a thermofusible substance) can be used. Such a heat-fusible substance is compatible with a reactive dye and a developer, thereby increasing the contact probability between these two components and exerting a sensitizing action.

  Examples of the heat-fusible substance include meta-terphenyl, parabenzylbiphenyl, dibenzyl terephthalate, phenyl 1-hydroxy-2-naphthoate, dibenzyl oxalate, di-o-chlorobenzyl adipate, 1,2- Di (3-methylphenoxy) ethane, di-p-methylbenzyl oxalate, di-p-chlorobenzyl oxalate, 1,2-bis (3,4-dimethylphenyl) ethane, 1,3-bis (2- And naphthoxy) propane.

  In the thermosensitive recording layer, the blending amount of the sensitizer is preferably 25 to 500 parts by mass, more preferably 100 to 300 parts by mass with respect to 100 parts by mass of the reactive dye.

  The thermal recording layer may further contain an image stabilizer for the main purpose of improving the storage stability of the thermal recording image.

  Examples of the image stabilizer include 1,1,3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert). -Butylphenyl) butane, 1,1-bis (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 4,4 '-[1,4-phenylenebis (1-methylethylidene)] bisphenol, And phenolic compounds such as 4,4 ′-[1,3-phenylenebis (1-methylethylidene)] bisphenol, 4-benzyloxyphenyl-4 ′-(2-methyl-2,3-epoxypropyloxy) Phenylsulfone, 4- (2-methyl-1,2-epoxyethyl) diphenylsulfone, and 4- (2-ethyl-1,2-epoxyethyl) 1) One or more selected from epoxy compounds such as diphenylsulfone and isocyanuric acid compounds such as 1,3,5-tris (2,6-dimethylbenzyl-3-hydroxy-4-tert-butyl) isocyanuric acid Things can be used. Of course, the image stabilizer is not limited to these, and two or more kinds of compounds may be used in combination as required.

  In the thermosensitive recording layer, the blending amount of the image stabilizer is preferably 5 to 100 parts by mass, and more preferably 10 to 60 parts by mass with respect to 100 parts by mass of the reactive dye.

  The heat-sensitive recording layer can further contain a crosslinking agent for three-dimensionally curing the above-described binder in order to improve water resistance.

  Examples of the crosslinking agent include aldehyde compounds such as glyoxal, polyamine compounds such as polyethyleneimine, epoxy compounds, polyamide resins, melamine resins, dimethylol urea compounds, aziridine compounds, blocked isocyanate compounds, ammonium persulfate and Examples thereof include diiron, and inorganic compounds such as magnesium chloride, sodium tetraborate, and potassium tetraborate, or boric acid, boric acid triesters, and boron-based polymers.

  In the heat-sensitive recording layer, the amount of the crosslinking agent is preferably in the range of 1 to 10% by mass with respect to the total solid content of the heat-sensitive recording layer.

  The heat-sensitive recording layer may further contain a pigment.

  Examples of the pigment include calcium carbonate, magnesium carbonate, kaolin, clay, talc, calcined clay, silica, diatomaceous earth, synthetic aluminum silicate, zinc oxide, titanium oxide, aluminum hydroxide, barium sulfate, and surface-treated calcium carbonate. And inorganic pigments such as silica and silica, and organic pigments such as urea-formalin resin, styrene-methacrylic acid copolymer resin, and polystyrene resin.

  In the heat-sensitive recording layer, the amount of the pigment is preferably such that the color density is not lowered, and is preferably 50% by mass or less based on the total solid content of the heat-sensitive recording layer. Moreover, 1-100 mass parts is preferable with respect to 100 mass parts of reactive dye, and 5-50 mass parts is more preferable.

  The heat-sensitive recording layer can further contain various additives generally used in heat-sensitive recording materials as required.

  Examples of such additives include waxes, metal soaps, colored dyes, fluorescent dyes, oil repellents, antifoaming agents, viscosity modifiers and the like.

  Examples of waxes include polyolefin waxes such as paraffin wax, carnauba wax, microcrystalline wax, and polyethylene wax; higher fatty acid amides such as stearic acid amide and ethylenebisstearic acid amide, higher fatty acid esters, and derivatives thereof. be able to. In particular, when a methylolated higher fatty acid amide is added to the heat-sensitive recording layer, a sensitizing effect can be obtained without deteriorating the background fog resistance.

  Examples of the metal soap include higher fatty acid polyvalent metal salts such as zinc stearate, aluminum stearate, calcium stearate, and zinc oleate.

  The thermal recording layer is prepared by, for example, preparing a coating liquid by dispersing a reactive dye, a developer and a binder, and optional components in a dispersion medium such as water, and applying this coating liquid on one side of a substrate. And can be formed by drying.

  At this time, it is preferable to disperse the reactive dye and the developer separately in the dispersion medium and to mix these dispersions when forming the heat-sensitive recording layer.

  The dispersion can be prepared using a stirring / pulverizing machine such as a ball mill, an attritor, or a sand mill.

  Examples of the coating method of the coating liquid include air knife coating, varibar blade coating, pure blade coating, rod blade coating, short dwell coating, curtain coating, die coating, and gravure coating.

  Further, the heat-sensitive recording layer formed as described above may be further subjected to a smoothing process using a known smoothing method such as a super calendar or a soft calendar. Thereby, the coloring sensitivity can be increased.

  In the smoothing process, the surface of the heat-sensitive recording layer may be applied to either a calendar metal roll or an elastic roll.

The basis weight of the heat-sensitive recording layer, considering the chromogenic, preferably ^{1~10g / m 2, 2~5g / m} 2 is more preferable.

  In the present invention, the thickness of the heat sensitive sheet is usually 75 to 160 μm, preferably 100 to 150 μm, more preferably 120 to 145 μm. When the heat sensitive sheet has a thickness of less than 75 μm, a transparent or translucent sheet is formed from the heat sensitive sheet. The thermal sheet may be distorted or curled when it is peeled off. If the thickness of the thermal sheet exceeds 160 μm, the print quality may deteriorate when printing on the thermal sheet using, for example, a thermal head. There is.

  In the present invention, the heat-sensitive sheet described in JP-A-2007-125847 or a sheet having both heat-sensitive and pressure-sensitive properties may be used as the heat-sensitive sheet. The heat-sensitive and / or pressure-sensitive sheet described in JP-A No. 2007-125847 has a pressure-sensitive recording layer on a substrate and, if necessary, a heat-sensitive recording layer. As the substrate and the heat-sensitive recording layer, the same materials as the above-mentioned heat-sensitive sheet can be used (for details, see JP-A-2007-125847).

  Examples of the heat and / or pressure sensitive sheet include DP80B manufactured by Oji Paper Co., Ltd., TW80KK manufactured by Nippon Paper Industries Co., Ltd., and the like.

Pseudo-adhesive layer According to a preferred embodiment, the laminated sheet of the present invention is formed by laminating a substrate, a heat-sensitive recording layer, a transparent or translucent sheet, and a concealing portion in this order. And a heat-sensitive recording layer, and a transparent or translucent sheet are bonded together in a peelable state with the heat-sensitive recording layer inside through a pseudo-adhesive layer.

  The pseudo-adhesion technique is known in the art, and for example, a pseudo-adhesion layer disclosed in Japanese Patent Application Laid-Open No. 2007-230098 (Patent Document 4) can be used.

  The pseudo-adhesive layer is not particularly limited as long as it has re-peelability and at the same time has the property that it cannot be re-applied. For example, the pseudo-adhesive layer generally contains a pseudo-adhesive generally used for pseudo-adhesion, and is optionally contained. It may be a layer composed of an adhesion control agent.

  There is no restriction | limiting in particular as a pseudo-adhesive which comprises a pseudo-adhesion layer, The thing generally used for the pseudo-adhesion can be used. Specific examples include, for example, rubber-based pressure-sensitive adhesives such as natural rubber and synthetic rubber; acrylic pressure-sensitive adhesives containing acrylic acid and / or acrylic acid ester as a main monomer component; vinyl acetate polymer, ethylene-vinyl acetate copolymer Examples thereof include vinyl acetate-based pressure-sensitive adhesives containing vinyl acetate as a main monomer component such as a polymer (EVA); polysaccharide-based pressure-sensitive adhesives such as starch and sodium alginate, and water-soluble adhesives such as dextrin-based pressure-sensitive adhesives.

  In the present invention, at least one pressure-sensitive adhesive selected from the group consisting of a rubber-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a vinyl acetate-based pressure-sensitive adhesive, and a dextrin-based pressure-sensitive adhesive is preferable because it can arbitrarily control adhesiveness. . The adhesiveness is appropriately set in consideration of, for example, the strength of the heat sensitive sheet, the strength of the transparent or translucent sheet, the adhesive strength between these sheets, and the like.

  Among these, in particular, when the pseudo adhesive layer is formed by a wet lamination method as described later, a vinyl acetate-based pressure-sensitive adhesive and / or a dextrin-based pressure-sensitive adhesive is preferable.

  In the pseudo adhesive layer, the blending amount of the pseudo adhesive is preferably 10 to 100% by mass, more preferably 20 to 80% by mass, based on the total solid content of the pseudo adhesive layer.

  The pseudo-adhesive layer preferably contains an adhesive strength adjusting agent in addition to the pseudo-adhesive.

  Examples of the adhesive strength modifier include waxes such as the above-described polyethylene wax, metal soap, inorganic pigments, and organic pigments. These adhesive force regulators have the effect of being dispersed in the pseudo adhesive layer and reducing the cohesive force of the pseudo adhesive layer. By reducing the cohesive force of the pseudo adhesive layer, the transparent or translucent sheet can be easily peeled off.

  In the pseudo adhesive layer, the blending amount of the adhesive strength adjusting agent is appropriately determined in consideration of the adhesive strength between sheets, the cohesive force of the pseudo adhesive layer, and the like. In particular, the amount of the adhesive strength between the sheets is preferably blended in an amount within the following range. For example, 0 to 90% by mass of the total solid content of the pseudo adhesive layer is preferable, and 20 to 80% by mass is more preferable.

The basis weight of the pseudo adhesive layer is preferably 0.5 to 10 g / m ^{2 and} more preferably 1 to 5 g / m ² because of excellent recording characteristics.

<Adhesive strength>
The adhesion strength between the sheets in the pseudo-adhesion layer is preferably 50 to 1000 mN / 25 mm (peeling speed 300 mm / min) in accordance with the T-type peeling test method defined in JIS K 6854-3. 80 to 600 mN / 25 mm (peeling speed 300 mm / min) is more preferable.

  When the adhesion strength according to the T-shaped peeling test method is 50 mN / 25 mm or more, it is possible to suppress the pseudo-bonded sheet from being naturally peeled off during transportation. Moreover, when the adhesive strength by the T-peeling test method is 1000 mN / 25 mm or less, problems such as breakage of the sheet and formation of a cylindrical shape with strong curling are unlikely to occur.

  The adhesive strength according to the T-type peeling test method defined in JIS K 6854-3 can be measured by the following procedure. That is, after leaving the sample in an environment of 23 ° C. and 50% RH for 24 hours or more, a peeling test is performed at a peeling speed of 300 mm / min. The bond strength is expressed in mN per 25 mm test sample width.

  The adhesive strength according to the T-peeling test method can be adjusted as appropriate depending on the type of pseudo-adhesive used, the coating amount, the time from application to pasting, the drying temperature, and the like. For example, if the application amount is the same, the longer the time from application to pasting, the more the coating liquid used for forming the pseudo-adhesion layer penetrates into the heat-sensitive recording layer or the transparent / translucent sheet, The amount of pseudo-adhesive that contributes to adhesion is reduced and the adhesion strength is reduced.

<Formation method>
The pseudo-adhesion layer can be formed using a coating liquid containing a pseudo-adhesive, a solvent-free one, an energy ray curable one, or the like. In the present invention, among these, a method using a coating solution containing a pseudo-adhesive (hereinafter sometimes referred to as a pseudo-adhesive layer forming coating solution) is preferable.

  As a coating solution for forming a pseudo-adhesive layer, a pseudo-adhesive such as a vinyl acetate-based pressure-sensitive adhesive is made into an aqueous emulsion, or a water-soluble pseudo-adhesive (for example, a dextrin-based pressure-sensitive adhesive) is dissolved in water to form an aqueous solution. And those using an organic solvent as a dispersion medium or solvent instead of water.

  When the pseudo-adhesive layer forming coating solution is used, the pseudo-adhesive layer is specifically formed by, for example, applying the pseudo-adhesive layer-forming coating solution on the heat-sensitive recording layer or on the transparent / translucent sheet. It can be formed by drying.

  Application of the pseudo-adhesive layer-forming coating solution can be performed by the same method as the coating method exemplified in the heat-sensitive recording layer.

  In the present invention, in particular, the pseudo-adhesive layer forms a coating layer by applying a coating liquid containing a pseudo-adhesive on a heat-sensitive recording layer or a transparent / translucent sheet, and the coating layer is It is formed by bonding two sheets through the coating layer and then drying the coating layer while in a wet state, that is, formed by a wet lamination method. It is preferable.

  Such a wet laminating method has various advantages over the dry laminating method.

  First, the wet lamination method has good productivity.

  For example, in the dry laminating method, for example, a coating solution containing a pseudo adhesive is applied to both of two sheets to be laminated, and after forming a pseudo adhesive layer by drying, the pseudo adhesive layers are opposed to each other, It is performed by applying pressure by applying superposition and strong pressure (usually) and heat. The pressure at this time is quite high. For example, considering mass production with a width of 1000 mm, it is necessary to apply a high pressure of 40 to 250 kg / cm as the linear pressure of the pressurization, and the pressurization is also uniform over the entire sheet. It is necessary to add to. Therefore, a very large device is required.

  Further, in the dry laminating method, for example, in order to improve the processing speed and increase the productivity by reducing the linear pressure, it is necessary to use a highly adhesive material as the pseudo-adhesive. However, if a pseudo-adhesive with high tackiness is used, blocking is likely to occur when the sheet on which the pseudo-adhesion layer is formed is stored in a wound state before crimping, or the adhesive strength of pseudo-adhesion after crimping. There is a problem related to stability, such as the time increases with time.

  In contrast, the wet laminating method does not require a strong pressure for bonding, and can be sufficiently pseudo-bonded even at about 1 kg / cm or less, for example.

  Further, in the dry laminating method, since the pressure is high, there is a loss of time until the pressurization operation condition reaches a predetermined speed, and accordingly, problems such as wrinkle loss that causes wrinkles on the sheet also occur and the yield decreases.

  On the other hand, the wet laminating method does not require a high pressure unlike the dry laminating method, and thus the above-mentioned problem is hardly caused and the productivity is good.

  Further, in the wet laminating method, the application amount of the pseudo adhesive layer may be smaller than in the dry laminating method.

  Since the application amount of the pseudo-adhesion layer is small, the time required for pasting and drying with the transparent / translucent sheet is short. Further, as the transparent / translucent sheet, a very thin sheet, for example, about 5 μm can be used. Therefore, the manufacturing cost is low.

  Further, according to the wet laminating method, the stability of the adhesive strength is also excellent. That is, in the dry laminating method, (1) the composition of the pseudo-adhesion layer (type and blending amount of the pseudo-adhesive, optional components, etc.), (2) the application amount of the pseudo-adhesive, (3) pressurizing conditions (pressure, The three main factors governing the strength of pseudo-adhesion are the processing speed and the like. On the other hand, in the wet laminating method, the factor (3) does not have to be taken into account, so that the adhesive strength is less stable and more stable.

  Further, according to the wet laminating method, the adhesive strength of the pseudo-adhesive layer is transported together with a severe process when used as a postcard which is a particularly preferred embodiment of the laminated sheet of the present invention, for example, with a large amount of postal items. It is easy to obtain a suitable adhesive strength that can withstand a transportation process, a high-speed machine sorting process, and the like. In addition, as described above, there is little variation and stable adhesive strength can be obtained. Therefore, the laminated sheet manufactured by the wet laminating method is useful for confidential postcards.

  That is, if the adhesion strength of the pseudo-adhesive layer is too low, there is a risk of peeling during the above process, and if it is too high, even if the process can cope with the above process, May break and information may not be confirmed.

  Thus, for laminated sheets used for confidential postcards, there is a conflicting requirement of high strength that does not peel in harsh processes and weakness that does not destroy the thermal recording layer during peeling, and suitable adhesion The range of strength is narrow. According to the wet laminating method, it is easier to make the adhesive strength within such a narrow range than in the dry laminating method.

  Furthermore, conventionally, when a laminated sheet is manufactured by the dry lamination method, usually, the printed surface is pseudo-bonded after printing information, so that there is an unstable factor that the adhesive strength changes depending on the printing rate. For this reason, since the amount of information printed on the confidential postcard varies depending on the individual, the printing rate also varies, and the adhesive strength may vary from postcard to postcard.

  On the other hand, when the pseudo-adhesion layer of the laminated sheet of the present invention is formed by the wet laminating method, individual information can be recorded by thermal recording after bonding, so there is little variation in adhesion strength between the laminated sheets, and as a postcard Suitable for use.

  Further, in the wet laminating method, as described above, the application amount of the pseudo-adhesive layer may be smaller than that in the dry laminating method. Therefore, the heat transferability of the pseudo adhesive layer is high, and clear recording can be performed at a high print density.

  In the dry laminating method, after the pseudo adhesive layer is formed, the two pseudo adhesive layers are pressure-bonded. Therefore, the pseudo adhesive layer itself has an adhesive property, and the two pseudo adhesive layers are pseudo-bonded by the affinity. ing. In order to provide adhesiveness, it is usually necessary to blend a low Tg (glass transition temperature) component (natural rubber, SBR (styrene butadiene rubber), etc.) in the pseudo-adhesive layer used in the dry laminating method. Therefore, when recording on a laminated sheet having such a pseudo-adhesive layer by the thermal recording method, the two pseudo-adhesive layers are melted and bonded together as a single layer by heat from the thermal head. . For this reason, the adhesive strength becomes too high, and it is difficult to peel off at this portion, and forcibly peeling off causes damage (breaking) of the sheet.

  On the other hand, in the wet laminating method, the two sheets are peeled off due to cohesive failure of the pseudo adhesive layer itself, so there is no need to blend a low Tg component for imparting tackiness into the pseudo adhesive layer. Therefore, the heat resistance of the pseudo-adhesive layer is high, and the above problems are unlikely to occur. Therefore, it is particularly suitable for thermal recording.

  When the pseudo-adhesive layer is formed by the wet laminating method, it is preferable that at least one of the base material of the heat-sensitive sheet and the transparent / translucent sheet, preferably both, is a gas-permeable base material such as paper.

  When forming a pseudo-adhesion layer by a wet laminating method, the process can be performed using a general coating apparatus, printing apparatus, or the like.

  In the conventional technology, when the pseudo adhesive layer is used, in the case of the thermal method, the components of the thermal recording layer and the pseudo adhesive layer are chemically or physically changed by heat, and the information described on the back side of the transparent / translucent sheet is transferred. There is a fear. However, in the present invention, the laminated sheet includes the resin layer as the outermost layer of the concealing portion, particularly in a desirable mode, and therefore it is possible to significantly prevent transfer of written information due to heat.

  The present invention will be described in more detail in the following examples, but the present invention is not limited to these examples.

Example 1
Transparent sheet (manufactured by Oji Paper Co., Ltd., trade name: glassine, length: 152.4 mm, width: 100 mm, thickness: 25 μm, light transmittance: 100%) and thermal sheet (trade name: PD450, made by Oji Paper Co., Ltd.) , Length: 152.4 mm, width: 100 mm, thickness: 145 μm), with the thermosensitive recording layer inside, pseudo-adhesion by a wet laminating method.
A multi-color offset printing machine (trade name: MVF18E) manufactured by Miyakoshi Machinery Co., Ltd. was applied to a part of the transparent sheet (length: 8 cm, width: 9 cm) with an ultraviolet curable white ink (T & K, trade name: Revised UV161 Conk White). ) To form a white shielding layer (thickness: 1.6 μm, light transmittance: 50%).
A multicolor offset printing machine (trade name: MVF18E) manufactured by Miyakoshi Machinery Co., Ltd. on the white shielding layer over the same area with the character background pattern (character size: 10 points, color: dark blue, character angle: random) shown in FIG. ) To form a character copy-forgery-inhibited pattern layer (thickness: 0.8 μm, ratio of character copy-forgery-inhibited pattern: 55% with respect to the total area of the character copy-forgery-inhibited pattern layer).
Next, over the same area, the camouflage background pattern (mesh background pattern, black) shown in FIG. 4 is printed on the character background pattern layer with a multicolor offset printing machine (trade name: MVF18E) manufactured by Miyakoshi Machinery Co., Ltd. (Thickness: 0.8 μm, ratio of camouflage tint block: 55% with respect to the total area of the camouflage tint block layer).
Over the same area, OP varnish (manufactured by Nippon Kayaku Co., Ltd., trade name: UFR-11D) was applied on the camouflage background pattern layer to form a transparent resin layer (thickness: 0.5 μm).

(Example 2)
According to Example 1, instead of the character background pattern used in Example 1, using the character background pattern (character size: 12 points and 14 points, color: deep blue, character angle: random) shown in FIG. A character background pattern layer (thickness: 0.8 μm, ratio of character background pattern: 65% with respect to the total area of the character background pattern layer) is formed, and instead of the camouflage background pattern shown in FIG. The camouflage tint block (black) shown in FIG. 5 further including the camouflage tint block consisting of the straight line shown in FIG. 6 is used as a camouflage tint block (thickness: 0.8 μm, ratio of the camouflage tint block: total area of the camouflage tint block layer) 67%) to form a laminated sheet.

(Example 3)
In accordance with Example 1, the color of the character background pattern was changed to a dark blue color to produce a laminated sheet.

Example 4
According to Example 1, the size of the character copy-forgery-inhibited pattern was changed from 10 points to 11 points to produce a laminated sheet.

(Example 5)
According to the first embodiment, the character copy-forgery-inhibited pattern shown in FIG. 8 (character size: 14 points, character angle: 0 ° (color: group blue) and 270 ° (color: deep blue), Was changed to a different font) to produce a laminated sheet.

  From the upper side of the concealed portion of the laminated sheets prepared in Examples 1 to 5, 9-point characters were printed by a thermal printer with a printer manufactured by Pentax (trade name: Pocket Book 30i).

  Information confidentiality of the laminated sheet produced in each example is (1) interpretation of concealment information from the front side of the concealed part (ie, the upper side of the concealed part of the laminated sheet), and (2) back side of the laminated sheet (ie, the laminated sheet) (3) Interpretation of concealment information when the laminated sheet is watermarked with light and (4) Information on the back side of the peeled transparent sheet (ie, pseudo-adhesive surface) The transfer was evaluated visually. The results are shown in the table below.

  In any of the laminated sheets of the present invention, the concealed information cannot be read from the front side and the back side, and the concealed information cannot be read even when watermarked with light. Furthermore, the laminated sheet of the present invention had excellent information confidentiality, with no written information transferred to the back side of the peeled transparent sheet. Such an effect of the present invention is that the above-described white shielding layer, character copy-forgery-inhibited pattern layer, and camouflage are formed on the upper side of the laminated sheet obtained by pseudo-bonding the heat-sensitive sheet and the transparent or translucent sheet with the heat-sensitive recording layer inside. This can be achieved by providing a concealing portion including a tint block layer and a resin layer. In particular, by providing a resin layer as the outermost layer of the concealment portion, a print that can be formed chemically and physically when writing confidential information on the thermal sheet underneath, for example, by a thermal system using a thermal head or the like. Scratches could be completely prevented.

  As a particularly preferable embodiment of the laminated sheet of the present invention, for example, a concealment postcard shown in FIG. 2 is mentioned, but the laminated sheet of the present invention is not limited to a postcard. For example, the laminated sheet of the present invention can also be used as a copy slip, receipt, card, lottery, etc. with high information concealment.

It is a schematic sectional drawing in the longitudinal direction of the concealment postcard which is one Embodiment of the lamination sheet of this invention. It is a top view of the concealment postcard which is one Embodiment of the lamination sheet of this invention. It is a figure which shows the example of the character copy-forgery-inhibited pattern of preferable embodiment of this invention. It is a figure which shows the example of the camouflage tint block of preferable embodiment of this invention. The example of the camouflage tint block of preferable embodiment of this invention is shown, and it shows that the camouflage tint block consisting of a straight line is included. It is a figure which shows only the camouflage tint block which consists of a straight line which may be contained in the camouflage tint block of preferable embodiment of this invention. It is a figure which shows the example of another character copy-forgery-inhibited pattern used by this invention. It is a figure which shows the example of another character copy-forgery-inhibited pattern used by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent or semi-transparent sheet 2 Thermal sheet 3 White shielding layer 4 Character tint layer 5 Camouflage tint layer 6 Resin layer

Claims (13)

  A laminated sheet comprising a heat-sensitive sheet and a transparent or translucent sheet formed on the heat-sensitive sheet, wherein a white shielding layer is formed on at least a part of the transparent or translucent sheet opposite to the heat-sensitive sheet; A laminated sheet having a concealing portion including a character background pattern layer, a camouflage background pattern layer, and a resin layer.   The laminated sheet according to claim 1, wherein the concealing portion is arranged by overlapping a white shielding layer, a character background pattern layer, a camouflage background pattern layer, and a resin layer in this order.   The laminated sheet according to claim 1 or 2, wherein the heat-sensitive sheet and the transparent or translucent sheet are pseudo-bonded.   The laminated sheet according to any one of claims 1 to 3, wherein a light transmittance of the white shielding layer is 80% or less of a light transmittance of the transparent or translucent sheet.   The laminated sheet according to any one of claims 1 to 4, wherein the light transmittance of the white shielding layer is 60% or less of the light transmittance of the transparent or translucent sheet.   The laminated sheet according to any one of claims 1 to 5, wherein a ratio of the character background pattern in the character background pattern layer is 30% or more with respect to a total area of the character background pattern layer.   The laminated sheet according to any one of claims 1 to 6, wherein a ratio of the camouflage background pattern in the camouflage background pattern layer is 30% or more with respect to the total area of the camouflage background pattern layer.   The laminated sheet according to any one of claims 1 to 7, wherein a ratio of the camouflage background pattern in the camouflage background pattern layer is 50 to 60% with respect to a total area of the camouflage background pattern layer.   The laminated sheet according to any one of claims 1 to 8, wherein the camouflaged background pattern in the camouflaged background pattern layer includes a straight line.   The laminated sheet according to any one of claims 1 to 9, wherein the resin layer is a transparent resin layer made of an ultraviolet curable resin.   The thickness of the said resin layer is 1 micrometer or less, The laminated sheet of any one of Claims 1-10.   The laminated sheet according to any one of claims 1 to 11, wherein information is written on the heat sensitive sheet from the upper side of the concealed portion by a heat sensitive method.   The laminated sheet according to any one of claims 1 to 12, which is used as a postcard.

Images