JPH04189596A - Data concealing adhesive sheet and postcard device using the same - Google Patents

Abstract

PURPOSE:To obtain a data concealing adhesive sheet dispensing with release paper to generate no wastefulness of resources and a post card device using the same by forming a transparent synthetic resin layer to one surface of a transparent curing resin cured layer or a vulcanized rubber layer while forming a transparent hot-melt layer to the other surface thereof and forming a transparent hot-melt layer to the exposed surface of the synthetic resin layer. CONSTITUTION:A data concealing adhesive sheet is interposed between two materials to be bonded, for example, two cards formed in a postcard form to bond both of them and, when the bonded materials are released, they are strongly bonded to a hot-melt layer but temporarily bonded between a transparent curing resin cured layer A or a transparent vulcanized rubber layer B and a synthetic resin layer C and, therefore, said materials are easily released. Since the transparent curing resin cured layer A or the transparent vulcanized layer B is already cured, when the materials are once opened, they are not again bonded even when they are again superposed one upon another to be bonded under heating. Therefore, the workability and productivity at the time of the manufacturing of a postcard concealing secret data can be markedly enhanced and the transaction of business can be simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Fields The present invention is applicable to applications such as national pension payment notices, employees' pension payment notices, deposit balances, securities, etc., which are displayed using characters, symbols, figures, photographs, etc. Concealing private information that you do not want others to know, such as transaction details, disease diagnosis results, or information that should be kept confidential in the trading world, such as information about product bargain sales, product lottery, prizes, and sweepstakes. This invention relates to an adhesive sheet for concealing information that is used for communication and simplifying office processing, and specifications for postcards using the same.

(b) Conventional technology Recently, when concealing information that has been accessed by computers, etc., and transmitting this information from a specific person to another specific person, administrative processing is simplified and the information is used effectively. things are being done.

Examples of means of transmitting this information include mail, internal mail, and the like.

Also, labels attached to products or information that should be kept confidential in the trading world, such as information on bargain sales of products,
Alternatively, information such as lottery tickets, prizes, etc. for a product is pasted on the product to hide the information.

(b) Traditionally, postcards have been used in large quantities as a means of transmitting information for general and business purposes, but since the communication section on the back of a postcard is visible to the public, the privacy of the individual's life and activities is violated. easy to be

In addition, in the case of conventional postcards, the contents of the communication column may become smudged or blurred and become unclear between the time the post is returned to the mailbox and the recipient picks up the post.

For this reason, for example, specific notifications that should be kept confidential, such as national pension payment details, employee pension payment details, information on bargain sales of products, bank deposit balances, securities transaction details, disease diagnosis results, etc., or information in the communication column. When it is necessary to convey the contents accurately to the recipient, the sender and sender usually take care to send the message in a sealed letter.

However, when making envelopes in this way, it is difficult to work as it requires unnecessary work such as inserting documents into envelopes and gluing them, and the postage costs are also unreasonably high compared to postcards. There were disadvantages such as economics.

In addition, there are many cases where it is necessary to transmit private information within a business office from a specific person to only other specific people by internal mail, etc., instead of by mail such as a postcard. In such cases, sealed letters are usually used, but this method has disadvantages such as the need for unnecessary work such as inserting documents into envelopes and gluing, which impairs work efficiency. Ta.

(b) Also, in recent trading circles, it is common for products to have labels, lottery tickets to be won on the spot, and prizes. In this case, a concealing adhesive sheet with the winning lottery grade printed on the back side is attached to the product. However, these labels and concealing adhesive sheets have a high adhesive strength, and when they are removed from the product, the product may be damaged or the concealing adhesive sheet may be torn, making it unclear what kind of lottery it is. .

Recently, the following postcards have been proposed to solve the above drawback (a).

Namely, (1) a transparent thermoplastic resin H-retaining film that is adhered to the back side of the postcard, a concealing cover sheet with a thermoplastic resin film laminated on the back side, and a cover sheet of the same type as the resin film. A postcard with a sticker has been proposed that is made of a thermoplastic resin and includes a bonding layer that is thermally extruded at a temperature lower than the melting point to releasably bond the protective film and the cover sheet (Jitsukaisho). 63
-6870 publication).

In addition, ■ a transparent thermoplastic resin protective film that is adhered to the back of a postcard that has been printed using computer processing, and a concealing cover that is laminated with a thermoplastic resin film on the back. a sheet, and a bonding layer made of a thermoplastic resin similar to the resin film and heat-pressed at a temperature lower than the melting point of the resin to releasably bond the protective film and the cover sheet. Postcards have been proposed (Jitsukai 63-1186)
Publication No. 3).

In addition, in order to eliminate the above drawback (b), the 0 surface base material and a polyester sheet are laminated via a polyethylene layer, an adhesive is applied to the surface of the polyester sheet, and a peeling method is applied to the adhesive-coated surface. A label sheet made of paper pasted together has been proposed (Utility Model Publication No. 57-60036).

In this label sheet, a polyester sheet and a polyethylene layer are bonded together with a weak adhesive force, and the polyethylene layer can be peeled off at a location where the adhesive force is weak.

(c) Problems to be solved by the invention However, in the above postcards (■) and (■), the parts that are to be firmly adhered so that they cannot be peeled off are heated by heating the two films to be adhered to each other using the same type of thermoplastic resin. , they are integrated when pressurized, and the parts that can be easily peeled off, that is, the parts where the postcard can be opened, are made by temporarily adhering the two films that should be adhered to each other using thermoplastic resins of different types. However, since these items are made of thermoplastic resin, after opening the postcard, if heated and pressurized with an iron or the like, they will be temporarily bonded again, leaving an important problem as described below.

That is, since this postcard can be re-adhered even after being opened, it is not possible to reliably protect the privacy of individuals.

In other words, after a third party opens the postcard and reads the contents of the correspondence field, if the opened postcard is heated and pressurized with an iron, etc., it will be temporarily attached again and return to its original state. Any number of people can easily open a postcard and read its contents.

Also, if you can easily open a postcard like this, you can rewrite or write in the communication column on the postcard.
Various failures occur.

In addition, the adhesive of the above label sheet (■) has tackiness,
A release paper is attached to the adhesive-coated surface to protect the surface or improve handling. When using this label sheet, the release paper is peeled off and the label is affixed to the product, while the peeled release paper is thrown away as garbage.

However, recently there has been great concern about the destruction of the global environment due to deforestation and mass depletion of fossil resources. For this reason,
Although various studies have been made to minimize the waste of resources for industrial and commercial materials, using release paper in this way goes against this requirement.

Furthermore, when a release paper is laminated on a label sheet in this way, not only does the cost of the label sheet become extremely high, but when the release paper is thrown away as garbage, there are problems such as a considerable amount of waste is required to dispose of the release paper.

Furthermore, when using this label sheet, it is necessary to peel off the release paper and attach it to the product, but this not only makes it difficult to attach the label sheet to the product, but also causes the peeled release paper to be thrown away as garbage. This requires a lot of effort and effort.

The present invention solves the above-mentioned technical problem. When a transparent curable resin cured layer or a vulcanized rubber cured layer and a thermoplastic resin layer or a cured layer different from these cured layers are adhered, While it is easy to peel off at the adhesive point, by using a transparent hot-melt layer or a transparent pressure-sensitive adhesive layer that develops adhesive properties when pressure is applied as the adhesive layer, release paper is unnecessary and resource waste is eliminated. The purpose of the present invention is to provide a concealing adhesive sheet and postcard specifications using the same.

By the way, in the present invention, a transparent curable resin cured layer or a vulcanized rubber cured layer that has been cured in advance is used, and a thermoplastic resin layer or a cured layer different in type from these cured layers is used. Once glued, it is easy to peel off at the adhesive point (and, moreover, open the postcard etc. at the adhesive point, stack it again, heat it,
Even if pressure is applied, this hardened layer prevents re-adhesion.

By the way, it is extremely easy to identify the person who intervened between the sending of the postcard and the time it is handed over to the person in question, so no one will open the postcard without permission, and the privacy of individuals will be reliably protected. be.

(d) Means for Solving the Problems In order to achieve this object, the adhesive sheet for information hiding of the present invention and the specifications for postcards using the same have taken the technical means described below.

That is, in the information-hiding adhesive sheet of Item 1, the transparent curable am cured layer (A) or the vulcanized rubber cured layer CB) has a transparent synthetic resin layer (C) on one side thereof.
and a transparent hot melt layer is formed on the other surface, and a transparent hot melt layer is formed on the exposed surface of the synthetic resin layer.

Book IIal! In the information-hiding adhesive sheet of Item 2, the transparent synthetic resin layer (C) in the information-hiding adhesive sheet is a transparent thermoplastic resin layer.

In the information hiding adhesive sheet of claim 3 of the present application, in the information hiding adhesive sheet, the transparent synthetic resin layer (C) is a transparent curable resin layer (A) of a different type from the transparent curable resin cured layer (A). fff! This is a hardened layer (A1).

In the information hiding adhesive sheet of claim 4 of the present application, in the information hiding adhesive sheet, instead of the transparent synthetic resin layer (C), a transparent vulcanized rubber cured layer (B) and a different type of transparent It is formed of a cured vulcanized rubber layer (Bl).

In the information-concealing adhesive sheet of claim 5 of the present application, in the information-concealing adhesive sheet, a transparent vulcanized resin is used instead of either of the bicurable resin cured layers (A) and (A1). A hardened rubber layer is formed.

In the information concealing adhesive sheet according to claim 6, in the information concealing adhesive sheet, a transparent thermally A plastic resin layer is formed.

In the information hiding adhesive sheet according to claim 7 of the present application, in the information hiding adhesive sheet described above, the true melt layer exhibits adhesiveness at a temperature of 40 to 100°C.

In the information hiding adhesive sheet of claim 8 of the present application, in the information hiding adhesive sheet described above, adhesiveness is developed by pressure instead of the hot melt layer on at least one side of the hot melt layers on both sides. It is formed by forming a transparent pressure-sensitive adhesive layer.

In the information-concealing adhesive sheet according to claim 9 of the present application, in the information-concealing adhesive sheet, the pressure-sensitive adhesive layer exhibits adhesive properties by breaking microcapsules under pressure.

In the adhesive sheet for information hiding according to claim 10 of the present application,
In the information-hiding adhesive sheet, the pressure-sensitive adhesive layer exhibits adhesive properties when the barrier layer is destroyed by pressure.

In the postcard specification of claim 11 of this Wi, the above-mentioned information-concealing adhesive sheet is interposed between two cards formed like a postcard and adhered.

In the postcard specification of claim 12 of the present application, the above-mentioned information-concealing adhesive sheet is interposed between and adhered to inner prayer cards formed like a double postcard.

Hereinafter, first, a transparent curable resin cured layer <A) or a vulcanized rubber cured layer (B) has a transparent synthetic resin layer (C) on one side thereof.
An adhesive sheet for information hiding, which has a transparent hot melt layer formed on the other surface thereof, and a transparent hot melt layer formed on the exposed surface of the synthetic resin layer will be described in detail.

The transparent curable resin cured layer (A) used in the present invention is not particularly limited as long as it is transparent and cured by heat, ultraviolet rays, electron beams, moisture, etc.

To form this curable resin cured layer (A), for example, first,
A transparent curable resin (described later) is formed by casting a solution of a fat on a peelable support, or this curable resin is formed by a spraying method, etc., and each of these is exposed to heat, ultraviolet rays, or electron beams. Further, various methods may be used, such as curing with wet x or the like, impregnating a transparent base material sheet with a transparent curable 64 fat solution, and curing this by the above-mentioned method.

Specific representative examples of the transparent curable resin used in the present invention include epoxy resin, unsaturated polyester resin, 7-ester resin, diallyl phthalate resin, thermosetting polyurethane resin, and ultraviolet curable polyurethane resin. ,
Moisture-curable polyurethane resins, electron beam-curable polyurethane resins, silicone resins, alkyd resins, etc. are listed, but from the viewpoint of flexibility, price, gloss, flexibility, etc., thermosetting polyurethane resins and ultraviolet-curable polyurethane resins are preferred. , electron beam curable polyurethane resins, moisture curable polyurethane resins, epoxy resins, unsaturated polyester resins, etc. are preferable.

Examples of the base sheet include a punched film made of transparent synthetic resin, a nonwoven fabric or woven fabric made of transparent synthetic fiber, or a nonwoven fabric or woven fabric made of glass fiber.

In forming this transparent curable resin cured layer <A), it is possible to make the curable resin contain additives such as a curing agent and a curing catalyst corresponding to the resin, and in this case, the curable resin 100 It is preferable that the additive is added in an amount of 0.1 to 30 parts by weight per part by weight.

In addition, the thickness of this curable resin cured layer is as follows:
It is not particularly limited as long as it has enough strength not to be damaged, but generally 6 to 250 μm, especially 12 to 50 μm.
If the thickness is less than 6μ, problems may arise in strength and handling.On the other hand, if it exceeds 250μ, transparency will decrease, it will be heavy, and It's the economy.

Further, the transparent cured vulcanized rubber layer (B) used in the present invention is not particularly limited as long as it is transparent and is obtained by vulcanizing and curing vulcanized rubber.

In order to form this transparent cured vulcanized rubber layer (B), for example, first a solution of transparent vulcanized rubber is formed on a removable support, and this is heated and vulcanized, or a vulcanizing agent is A mixture of raw rubber (sliced) containing
It may also be formed by impregnating a transparent base sheet similar to the above with a solution of transparent vulcanized rubber, and vulcanizing and curing this in the same manner as above.

Examples of the vulcanized rubber used in the present invention include rubber elasticity rubber having a molecular weight of 100,000 to 1,000,000 and containing a vulcanizing agent. Specifically, for example, homopolymers such as natural rubber, acrylic rubber, acrylonitrile rubber, nitrile rubber, styrene rubber, styrene-butanoene rubber, butadiene rubber, inbrene rubber, chloroprene rubber, or butyl rubber, or copolymers of two or more of these rubbers. polymer,
Further examples include mixtures of two or more of these.

Furthermore, known vulcanizing agents can be used in the present invention.

The thickness of this cured vulcanized rubber is not particularly limited as long as it has enough strength to not break when peeled off, but it is generally desirable to be in the range of 6 to 250 μI, particularly 12 to 50 μI; If the thickness is less than 6 μm, there are problems with strength and handleability, while if it exceeds 250 μm, the transparency decreases, it becomes heavy, and it is uneconomical.

In the present invention, the above transparent curable resin cured layer (A
) or the cured vulcanized rubber layer (B) has a transparent synthetic resin layer (C) formed on one side thereof and a transparent hot melt layer formed on the other side.

The transparent synthetic resin layer (C) used in the present invention includes:
It may be formed of any synthetic resin, such as a transparent thermoplastic resin or a thermosetting resin, and is not particularly limited.

Specific representative examples include polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinylidene chloride resin, polycarbonate, aromatic or aliphatic polyamide, polysulfone, polyester, polystyrene, polyurethane, polyvinyl alcohol, or Poly7crylonitrile, polyimide, polyphenylene oxide, polyphenylene sulfide, polyamideimide, bismaleimide/triazine, epoxy resin, polyamide/bismaleimide, polyacetal, poly, ether ether ketone, polyether sulfone,
Examples include transparent layers formed of synthetic fats such as Boria Relay 1 and polyoxybenzoyl, and these can be used alone or in a stack of two or more.

As a method for forming this transparent synthetic am layer, any known method such as a coating method, a spreading method, a laminating method, etc. may be appropriately employed.

The thickness of this transparent synthetic resin layer is not particularly limited, but is generally 0.1 to 100 μm, particularly 0.1 to 5 μm.
．． It is desirable to keep it within the range of 0μ theory, %, 1.

That is, by forming the transparent synthetic resin layer (C) in this way, the opening of the synthetic resin layer (C) and the transparent curable resin cured layer (A) or the vulcanized rubber cured layer (B) is achieved. This makes peeling easier. In this case, this thickness is 0.1
If the thickness is less than 100 μW, a uniform layer cannot be formed, which may cause problems in peelability. On the other hand, if it exceeds 100 μW, it becomes too thick, causing problems in transparency, and is also heavy and uneconomical.

In addition, in the present invention, the other surface of the above-mentioned curable resin cured layer (A) or vulcanized rubber cured layer (B), that is, the synthetic resin layer (C
) A transparent hot melt layer is formed on the opposite side.

This hot melt layer is particularly limited as long as it exhibits adhesive properties at a temperature below the deterioration temperature of the above-mentioned cured layer (A) or (B) and firmly adheres to postcard-like cards, etc., which will be described later. Generally below 130℃, especially at 4℃
It is preferable to use one that exhibits adhesive properties at 0 to 100°C.

Specific examples of this hot melt layer include saturated polyester resins, polyamide resins, cellulose resins, polyacetal resins, etc. In addition to those that exhibit hot melt properties alone, they are often used in combination with tackifiers, plasticizers, etc. Various rubbery polymers such as nitrile rubber and various polymers such as ethylene-vinyl acetate copolymer are included. These polymers may be a mixture of two or more types, if necessary.

This hot melt layer is formed by a known method.

The thickness of this hot melt layer is not particularly limited, but is generally desirably in the range of 0.1 to 50 μm, particularly 1 to 5 μm; if this thickness is less than 0.1 μm, it will not form a homogeneous layer. On the other hand, if the thickness exceeds 50 μm, there will be problems with transparency, the thickness will be heavy, and it will be uneconomical.

By the way, when forming this hot melt layer, if there is a possibility that the obtained hot melt layer may cause blocking, fine powder of starch or fine powder of thermoplastic resin such as polyethylene may be sprinkled on the surface of the hot melt layer. Alternatively, the use of release paper can be avoided by forming a diaphragm with an alkyl 7 ether or xylene resin to suppress blocking.

Furthermore, in the present invention, a hot melt layer is formed on the exposed surface of the synthetic resin layer (C), and examples of the hot melt layer include those similar to those described above; The method and thickness are the same as in the above case, so they will be omitted.

Since the adhesive sheet for information concealment of the present invention has the above structure, it can significantly improve workability and productivity when manufacturing postcards, etc. that conceal confidential information, for the reasons described below. This not only simplifies administrative processes, but also allows for uniform and stable postcards, etc. Moreover, since the blocking of this hot melt layer is suppressed, there is no need to use release paper. Therefore, not only no resources are wasted, but also costs can be reduced.

In the present invention, the information-concealing adhesive sheet is interposed between and adhered to an adherend, for example, two cards shaped like a postcard, and when this is peeled off, the hot melt layer and the adherend are bonded together. are strongly adhered to each other, while the transparent curable resin layer (A) or the vulcanized rubber layer (B) and the synthetic resin layer (C)
) are temporarily bonded, so they can be easily peeled off between them.Moreover, since the transparent curable resin cured layer (A) or the vulcanized rubber cured layer (B) has already been cured, the Once opened, even if they are stacked again and heated and pressurized, they will not re-adhere.

By the way, it is extremely easy to identify the person who passed the postcard or product from the sender to the recipient, so no one will open the postcard without permission, and the confidentiality of information will be more securely protected. It will be done.

In the present invention, in the information-hiding adhesive sheet, the one in which the transparent synthetic resin layer (C) is a transparent thermoplastic resin layer allows highly transparent sheets to be obtained very easily and has good productivity. It is the best option because it is inexpensive and has good removability.

That is, in this adhesive sheet for information hiding, a transparent thermoplastic resin layer is formed on one side of the transparent curable resin cured layer (A) or the vulcanized rubber cured layer (B), and a transparent thermoplastic resin layer is formed on the other side. A hot melt layer is formed, and a transparent hot melt layer is formed on the exposed surface of the thermoplastic resin layer.

This thermoplastic resin layer is not particularly limited.

Specific typical examples of this thermoplastic resin layer include polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinylidene chloride resin, polyamide, polyester, polystyrene, polyurethane, polycarbonate, polyvinyl alcohol, polyacrylonitrile, etc. In addition, the present invention particularly includes synthetic rubbers such as polybutadiene and polyisoprene.

As a method for forming this thermoplastic resin layer, a known method such as a coating method, a spreading method, or a lamination F method is used.
The above thermoplastic resin layer may be formed on the transparent curable resin cured layer (A) or the vulcanized rubber cured layer (B).

The thickness of this thermoplastic resin layer is not particularly limited, but is generally 0.1 to 100μ, particularly 0.1 to 5.
It is preferable that the thickness is in the range of 0 μl, and this thickness is 0.1 μl.
If it is less than 100 μm, it will be difficult to form a uniform layer and the releasability will be poor. On the other hand, if it exceeds 100 μm, transparency will decrease, it will become heavy and it will be uneconomical.

In this way, since the curable resin or vulcanized rubber is cured or vulcanized in advance, the curable resin cured layer (A
) or the vulcanized rubber cured layer (B) and the transparent thermoplastic resin layer, it becomes impossible to re-adhere even if they are stacked again and heated and pressurized.

In the adhesive sheet for information hiding of the present invention, there is also one in which the transparent synthetic resin layer (C) is a transparent curable resin cured layer (AI) different in type from the transparent curable resin cured layer (A). It is incense.

That is, this information hiding adhesive sheet F has a transparent curable resin cured layer (A) or a vulcanized rubber cured layer (B) on one side of which is a transparent curable resin cured layer (A) of a different type. A transparent curable resin cured layer (A1) is formed, a transparent real melt layer is formed on the other side, and a transparent hot melt layer is formed on the exposed surface of the curable resin cured layer (A1). That's what happens.

In the present invention, a transparent curable resin cured layer (A1) of a different type is formed on one side of the curable resin cured layer (A). It firmly adheres to the hot melt layer and has appropriate releasability to the cured layer (A).

As this curable resin cured layer (A1), the above-mentioned curable resin can be mentioned, but in this case, this curable resin cured layer (
A1) needs to be transparent so that the information can be deciphered by peeling it off.

In addition, for this curable resin cured layer (A1), special care must be taken to use a curable resin different from the curable resin used to form the curable resin cured layer (A). By forming the curable resin cured layer (A) and the curable resin cured layer (A1) using different curable resins in this way, it becomes possible to separate them.

In the present invention, in order to form a curable resin cured layer (A1) on one side of the curable resin cured layer (A), the cured layer (
A) Form by casting a solution of a different type of transparent curable resin on top of the above, or form this transparent curable resin by a spraying method, etc., and apply heat or ultraviolet rays to each layer. Alternatively, the electronic Jomon can be cured by moisture, etc., or a transparent base sheet can be laminated on the cured layer (A), this base sheet can be impregnated with a transparent curable resin solution, and this can be cured using the method described above. Examples include various methods such as curing.

In addition, a transparent base sheet is impregnated with a solution of a transparent curable resin, and this is cured in advance to B stake, and the sheet cured to B stake is laminated on the cured layer (A) to create a temporary layer. They may be glued together and completely cured using the method described above.

In forming this transparent curable resin cured layer (A1), it is possible to incorporate additives such as a curing agent and a curing catalyst corresponding to the resin into the transparent hard (monocurable) resin. Additive 0.1 to 100 parts by weight of curable resin
It is desirable that the amount is 30 parts by weight.

Further, the thickness of this curable resin cured layer is not particularly limited, but is generally 0.1 to 100 μm, particularly 0.2 to 1 μm.
It is preferable that the thickness is in the range of 0 μm, and this thickness is 0.1 μm.
If the thickness is less than 100 μm, it may be difficult to obtain a uniform layer and adequate releasability may not be obtained. On the other hand, if the thickness exceeds 100 μm, problems may arise in transparency, the thickness becomes heavy, and it is uneconomical.

In addition, the present invention also includes a case in which a transparent curable resin cured layer (A1) is formed on one side of the heated rubber cured layer (B), but in this case, the formation of the curable resin cured layer (A1) The method is the same as above.

In this way, since the curable resin cured layer (A) or the heated rubber cured layer (B) and the transparent curable resin cured layer (A1) are cured in advance, when a postcard or the like is opened between them, it will not work again. Since it does not re-adhere even when heated and pressurized, it has the same effect as described above.

In the information hiding adhesive sheet of the present invention, the transparent synthetic resin layer (
Instead of C), it is also advantageous to use a transparent cured rubber layer (B1) of a different type from the cured transparent rubber layer (B) for the same reason as in the above case.

That is, in this adhesive sheet for information hiding, the transparent curable resin cured layer (A) or the vulcanized rubber cured layer (B) has a transparent vulcanized rubber cured layer (B) and a different type of transparent layer on one side. A cured vulcanized rubber layer (B1) is formed, and a transparent hot melt layer is formed on the other side, and the cured vulcanized rubber layer (B1) is
) is formed by forming a transparent hot melt layer on the exposed surface.

In the present invention, the vulcanized rubber cured layer (B) is provided on one side of the transparent curable resin cured layer (A) or the vulcanized rubber cured layer (B).
To form a transparent vulcanized rubber cured layer (B1) of a different type, for example, first, a transparent vulcanized rubber solution is added to the above-mentioned curable resin cured layer (A) or vulcanized rubber cured layer (B). The above-mentioned curable material is coated on one side of the rubber and then heated and vulcanized. Alternatively, a mixture of raw rubber containing a vulcanizing agent (massified) is formed into a sheet, and this is coated with the above-mentioned curable material. Resin hardening layer (A
) or laminated on one side of the vulcanized rubber cured layer (B) and then heated and vulcanized, or a transparent base material is placed on one side of the above curable resin cured layer (A) or vulcanized rubber cured layer (B). Stack the sheets,
This base sheet may be impregnated with a solution of vulcanized rubber, and then vulcanized and cured in the same manner as described above. In this case, special attention must be paid to the fact that the cured vulcanized rubber layer (B) and the cured vulcanized rubber layer (B1) are made of different types of transparent vulcanized rubber. This allows for separation between the two.

Further, as the above-mentioned vulcanizing agent, known ones can be mentioned.

The thickness of the cured vulcanized rubber layer (B1) is not particularly limited, but is generally 0.1 to 100 μm, particularly 1 to 5 μm.
The thickness is preferably in the range of 0.1μ-
If the thickness is less than 100 μm, a uniform thin film cannot be obtained and the quality may become unstable, such as problems with peelability.
Exceeding this will not only cause problems with transparency, but will also be heavy and uneconomical.

In the present invention, the curable resin cured layer (A
) or vulcanized rubber cured layer (B) and vulcanized rubber cured layer (B1)
Since it has been cured in advance, it adheres to the adherend and when it is peeled off, the gap between the curable resin cured layer (A) or the vulcanized rubber cured layer (B) and the vulcanized rubber cured layer (B1) is removed. After this peeling, even if they are heated and pressed again, they will not be re-adhered, resulting in the same effect as described above.

In the adhesive sheet for information hiding of the present invention, in the above-mentioned adhesive sheet for information hiding, in place of either one of the transparent bicurable resin cured layers (A) and (A1), Also useful are those formed from transparent vulcanized rubber cured layers.

The material, formation method, thickness, etc. of the cured vulcanized rubber layer used in the present invention are the same as those for the information-hiding adhesive sheet described above.

As described above, in the present invention, the curable resin cured layer and the vulcanized rubber cured layer are cured or vulcanized in advance, and the peeling portion of the information hiding adhesive sheet is formed by this alternating combination. Therefore, for the reasons described below, it is possible to significantly improve workability and productivity when manufacturing postcards, etc., simplify and rationalize administrative processing, and produce uniform and stable postcards, etc. Moreover, once these postcards are opened at the peeled point, they do not adhere even if they are stacked again and heated and pressurized.
Since opening/closing by a third party is prevented, the confidentiality of information is further ensured.

Further, the true melt layer used here does not require a release paper as in the case described above, so not only is there no waste of resources, but it is also possible to reduce costs.

In the information-hiding adhesive sheet of the present invention, in the above-mentioned information-hiding adhesive sheet, in place of either one of the transparent double-curing resin cured layers (A) and (A1),
Even peaches with a transparent thermoplastic resin layer are fragrant.

The material, forming method, thickness, etc. of the thermoplastic resin layer used in the present invention are the same as those for the information-hiding adhesive sheet described above.

As described above, in the present invention, the curable resin cured layer is cured in advance, and the peeling point of the information hiding adhesive sheet is formed by combining the curable resin cured layer and the thermoplastic resin layer. As a result, for the reasons described below, it is possible to significantly improve workability and productivity when manufacturing postcards, etc., simplify and streamline administrative processing, and produce uniform and stable postcards. Moreover, once these postcards are opened at the peeled point, they do not adhere even if they are stacked again and heated and pressurized, which prevents third parties from opening and closing the information, making the information even more confidential. It is guaranteed.

Further, the hot melt layer used here does not require a release paper as in the case described above, so not only is there no waste of resources, but it is also possible to reduce costs.

Since the adhesive sheet for information hiding of the present invention has the above structure, in addition to the effects of the adhesive sheet for information hiding described above, surface smoothness is ensured by the formation of a transparent synthetic resin layer. The transparency becomes even higher, making it easier to decipher the -layer secret information.

In the present invention, it is advantageous for the above-mentioned adhesive sheet for information hiding to have a transparent hot melt layer that exhibits adhesive properties at 40 to 100''C.

In other words, this adhesive sheet for information concealment is intended to simplify and speed up office processing by concealing information emitted by a computer or the like with an adherend, but the adhesive properties of the hot melt layer If the temperature is too high, the adhesiveness and adhesion speed with postcard-like cards, which will be described later, as well as the heat capacity of the processing equipment, etc. become important. For this reason, it is desirable that the temperature at which the hot melt layer exhibits adhesive properties is as low as possible. If the temperature at which the hot melt layer develops adhesive properties is less than 40°C, problems may occur in terms of storage stability and handling.On the other hand, if the temperature exceeds 100°C, problems may occur in terms of adhesiveness, adhesion speed, etc. This is not desirable because it may cause problems in further simplifying and speeding up administrative processing.

By the way, this hot melt layer is not particularly limited as long as it exhibits adhesiveness at a temperature of 40 to 100 DEG C., and the hot melt layer is selected and used from those mentioned above.

Further, the material, forming method, and thickness of this hot melt layer are the same as those described above, and therefore will not be described here.

In the present invention, in the above-mentioned adhesive sheet for information hiding, a pressure-sensitive adhesive layer that exhibits adhesive properties under pressure is laminated in place of the hot-melt layer on at least one side of the hot-melt layers on both sides. Things are also beneficial.

That is, in the above adhesive sheet for information hiding, instead of the hot melt layer on both sides, (1) one side has a hot melt layer and the other side has a pressure sensitive adhesive layer, or (2) both sides have a pressure sensitive adhesive layer. All of these are beneficial.

Examples of this pressure-sensitive adhesive layer include those that exhibit adhesive properties by breaking microcapsules under pressure.

Specifically, for example, microcapsules filled with an adhesive may be fixed to both sides of an adhesive sheet for information hiding, and this fixing method involves heating the above sheet F to partially melt it. All you have to do is sprinkle microcapsules on top of this and adhere it.

It is also advantageous that the pressure-sensitive adhesive layer exhibits adhesiveness not only due to the destruction of the microcapsules, but also due to the destruction of the barrier layer upon application of pressure.

In this method, adhesive layers are formed on both sides of an adhesive sheet for information hiding, and fine powder of starch or fine powder of thermoplastic resin such as polyethylene is sprinkled on the surface of each adhesive layer.
A barrier layer consisting of a diaphragm made of alkylphenol or xylene resin may be formed to prevent blocking of the adhesive layer.

The above adhesive layer includes vinyl acetate adhesive, polyvinyl alcohol adhesive, polyvinyl acetal adhesive, vinyl chloride adhesive, acrylic adhesive, polyamide adhesive, polyethylene adhesive, cellulose adhesive, and chloroprene adhesive. Examples include layers formed of a (neobrene) adhesive, a nitrile rubber adhesive, a styrene rubber adhesive, a polysulfide adhesive, a butyl rubber adhesive, and a silicone rubber adhesive.

The thickness of this adhesive layer is 3 to 50 μm, especially 5 to 20 μm.
A thickness in the range of μm is desirable; if the thickness is less than 3 μm, a uniform adhesive layer may not be obtained or the adhesive force may be too weak, which is undesirable. On the other hand, if the thickness exceeds 50 μm, the sheet may become heavy or It is undesirable because it becomes thicker, making it difficult to handle and being uneconomical.

In this way, in the present invention, by using a pressure-sensitive adhesive layer that develops adhesive properties when pressure is applied, it is possible to continuously adhere to the adherend while applying pressure with a pressure roll, and the adhesiveness to the adherend can be continuously bonded. Not only can the workability and productivity of the process be improved significantly, but also a homogeneous and stable product can be obtained.

In addition, the pressure-sensitive adhesive layer used here suppresses blocking by microencapsulating the adhesive and forming a barrier layer on the surface of the adhesive layer, so no release paper is required as in the case above. Therefore, not only is there no wastage of resources, but costs can also be reduced.

By the way, in the present invention, since the curable resin cured layer is cured in advance, it is easy to open the postcard etc. at the point where the curable resin is cured. Even if heated and pressurized, this hardening resin hardening layer will not re-adhere because it has been hardened.

By the way, it is very easy to determine what kind of person was involved between the sender and the recipient of the postcard or product, so no one will open the postcard without permission, and the confidentiality of information will be more securely protected. It will be done.

The #&adhesive sheet for information hiding of the present invention may include, if desired,
Various compounding agents such as anti-aging agents, antioxidants, flame retardants, dyes and pigments may be added.

By the way, in the present invention, transparent means that the letters, symbols, figures, photographs, etc. in the communication column may be colored as long as they can be easily seen.

In the present invention, the above-mentioned information-concealing adhesive sheet F is layered with a card or product normally formed to postcard specifications, or is layered in the form of a sheet punched out with a Humbutter and heated and pressurized. , used in various applications.

In the postcard specification of the present invention, the information-concealing adhesive sheet is interposed between two cards formed to the IYI regular postcard specification, or between a center-folding card formed to the double-postcard specification. It is formed by heating, pressurizing, or applying pressure. In this case, postcard specifications include not only normal postcards and double postcards, but also those that differ in size, weight, etc. from these postcards, and in short, include those in the form of cards or sheets.

In this case, the heating conditions for the hot melt layer are at least the adhesive development temperature of the hot melt layer used;
The process is carried out at a temperature below the deterioration temperature of the layers constituting the adhesive sheet for information hiding, and the pressure conditions are 10 to 1.
10000/c plus 2, especially 100-10000g/c
You can do it with K2.

Also, if this pressure condition is less than 10 g/cm2, optical spectroscopic adhesion may not occur;
If it exceeds m'', it is meaningless.

Further, in the case of a pressure-sensitive adhesive layer, pressure is applied at a pressure higher than the pressure at which the adhesive property is developed, that is, at a pressure higher than the pressure at which the microcapsules and the barrier layer are destroyed.

In this case, the pressure conditions are generally 100 to 10,000
00s/cc2, especially 2000-1000008/cI
I went to 112 and it was good.

In addition, the adherends used here, such as cards, have the functionality and strength to withstand use as opaque and concealable postcards, labels, etc.
There are no particular limitations as long as symbols, figures, photographs, etc. can be displayed.Specifically, for example, a sheet made of paper or synthetic resin, or paper etc. impregnated with synthetic resin. Examples include those made by laminating paper with a synthetic resin film. This card or the like may itself have a concealing power, or even if it does not have a concealing power itself, it may be given a concealing power by printing or the like.

(e) Effect The information hiding adhesive sheet of the present invention has the above configuration,
It is usually used for various purposes by stacking it on a card or product shaped like a postcard, or by stacking it in the form of a computer-printed sheet and heating and pressurizing it.

This adhesive sheet for information hiding has a hiding power on the adherend such as a card, and secret information such as a communication column on the inside cannot be read from the outside.

For example, when the recipient of a postcard, etc. (adherent) formed using this information-concealing adhesive card takes the postcard, etc. and opens it, the information-concealing adhesive sheet on the postcard, etc. The melt layer or pressure-sensitive adhesive layer and the adherend are firmly adhered, while the transparent curable resin cured layer (A) or the vulcanized rubber cured layer (B) and the synthetic resin layer ( C) Or, since the vulcanized rubber cured layer is properly temporarily bonded at the location, it can be opened relatively easily at that location, allowing the recipient of the postcard etc. to easily read the contents of the confidential information. It is.

By the way, in the present invention, the curable resin cured layer (A)
Alternatively, since the cured vulcanized rubber layer (B) has been cured in advance, once a postcard or the like is opened at the above-mentioned location, it is difficult to re-adhere even if it is stacked again and heated and pressurized.

In this way, if a postcard, etc. is opened once and cannot be re-attached, it is extremely easy to identify the person who intervened between the time the postcard, etc. was sent and the time it was handed over to the person who received it. There will be no people left, and the privacy of individuals will be more securely protected.

Furthermore, since postcards, etc. cannot be opened without permission, accidents such as rewriting or writing of the contents of the communication column on postcards, etc., do not occur.

Furthermore, since blocking of the hot melt layer or pressure sensitive adhesive layer in the information hiding adhesive sheet of the present invention is suppressed, there is no need to use a release paper.

In particular, in the information hiding adhesive sheet F of the present invention, adhesiveness can be increased by applying pressure instead of the hot melt layer on at least one side of the hot melt layer on both sides.
：Seiazuki Layer Hondo Kochusu> When forming lid feces, etc., it is sufficient to simply apply pressure with a pressure roll, or it is sufficient to install equipment that pressurizes and heats only one side with a hot plate, hot roll, etc. This has the effect of simplifying the equipment.

In this case, in place of the hot melt layer on both sides of the adhesive sheet for information hiding of the present invention, if a pressure-sensitive adhesive layer that develops adhesiveness by pressure is formed, when forming postcards etc., the pressure-sensitive adhesive layer can be used. It is possible to bond the adherend continuously while applying pressure, which eliminates the need for heating means, which simplifies equipment, and improves workability and productivity when bonding with the adherend. Moreover, it is possible to obtain a homogeneous and stable product.

In the postcard specification of the present invention, the above-mentioned information-concealing adhesive sheet is placed between two cards formed in a normal confectionery format, or in a center-fold type card formed in a two-way postcard specification. It is manufactured continuously by heating, pressurizing, or pressurizing the material in between, and has the effect of concealing information and simplifying and speeding up administrative processing.

(f) Examples Hereinafter, the present invention will be explained in detail based on Examples, but the present invention is not limited thereto.

Example 1 The following was used as the transparent thermosetting resin cured layer (A).

That is, in forming the transparent thermosetting resin cured layer (A), A of the thermosetting polyurethane resin manufactured by Nippon Paint Co., Ltd. under the trade name "Biposi 50" is used.
Blend the liquid and B liquid at a ratio of 721 (volume ratio), and add to this mixture,
Furthermore, a 20% by weight transparent solution was obtained using a xylene solvent, and this solution was uniformly coated on a releasable support.
Cured at 20°C for 20 minutes at a thickness of 30μ.
A transparent thermosetting resin cured layer was formed and peeled off.

Next, a transparent cured vulcanized rubber layer was formed on one side of the above-mentioned transparent thermosetting resin cured layer (A) by applying no more than one coat on each side.

That is, to form a transparent cured vulcanized rubber layer, first, acrylic rubber with a molecular weight of 500,000 to 700,000 ``Varaclone 248E'' manufactured by Kigami Kogyo Co., Ltd. is used as a material, and this is dissolved in toluene to give a weight of 10% % solution was obtained. Next, as a vulcanizing agent, 1 part of 3 parts of isocyanate produced by Nippon Polyurethane Kogyo Co., Ltd. (product name: Flonay L, solid content 75% by weight) per 100 parts by weight of the above acrylic rubber (solid content) was added. Added.

Next, a rubber solution containing the above-mentioned vulcanizing agent was uniformly coated on the above-mentioned thermosetting resin cured layer <A1) using a kiss coater.
Heat vulcanization was performed at 0° C. for 2 minutes to obtain a transparent cured vulcanized rubber layer with a thickness of 5 μm.

Furthermore, hot melt layers were formed on both sides of the laminated sheet by the following method.

That is, as m blood for forming a water melt layer,
EMA (ethylene methyl acrylate) manufactured by Chevron Chemical Company, product name DS1009/2 with methyl acrylate content of 33% by weight (melting point 57°C, softening point 23°C)
This was further diluted to 10% by weight with toluene. .

After immersing the laminated sheet in this solution, remove the excess resin solution from both sides using a doctor, and heat it for 10 minutes at 100"C.
Drying was carried out for a minute to form a 1.5 μm honomelt layer on one side.

Thus, the hot melt layer, the curable resin cured layer (A),
An adhesive sheet for postcards of the present invention comprising a cured vulcanized rubber layer and a hot+melt layer was obtained.

Example 2 Using the adhesive sheet for information hiding obtained in Example 1, a postcard specification of the present invention was obtained by the following method.

That is, in forming the postcard specifications of the present invention, the above-mentioned information-concealing adhesive sheet was interposed between two postcard-shaped cards, and this was rolled with a 50"C pressure roll.
By continuously heating and pressurizing at 60 W/min under a pressure of 000 g/cm2, one postcard specification of the present invention having a secret function was obtained.

This postcard specification could be easily peeled off between the curable resin cured layer (A) and the transparent vulcanized rubber cured layer, and the contents (information) of the communication column could be read with ease. In addition, when you open a postcard like this, the curable resin cured layer (A) has already been cured, and the vulcanized rubber cured layer has been cured, so even if you stack it again and apply heat and pressure, it will not work again. It was observed that no adhesion occurred.

Further, after opening this postcard specification, an attempt was made to rewrite the contents of the communication column in the postcard specification, but due to the vulcanization of the vulcanized rubber hardening layer, the rewriting could not be completed.

By the way, in the present invention, the vulcanized rubber layer in the adhesive sheet for information hiding is cured in advance, and it is only necessary to heat and melt the hot melt layer of the sheet to develop adhesive properties. When forming a postcard by overlapping it with a postcard-like card, it can be bonded securely to the postcard-like card in a short time, and it can also significantly improve workability and productivity when manufacturing postcards. It was recognized that this method not only simplifies and streamlines administrative processes, but also enables the production of uniform and stable postcards.

Furthermore, this hot/melt layer has no fear of blocking, and there is no need to use a release paper.Therefore, not only is there no waste of resources, but it is also possible to reduce costs.

Example 3 A transparent curable resin cured layer (A>
A laminated sheet consisting of a transparent cured vulcanized rubber layer was obtained, and then a transparent pressure-sensitive adhesive layer, which exhibits adhesive properties when pressed, was formed on image f of this laminated sheet by the following method.

That is, an emulsion-polymerized acrylic pressure-sensitive adhesive is prepared using butyl acrylate as a main monomer as a microcapsule type thickening agent and acrylamide as a monomer as a functional group-containing aggregating component.

Next, styrene was added for microcapsulation, and a two-stage emulsion polymerization was performed to obtain a microcapsule-type emulsion-type adhesive coated with 2 to 3 molecular layers of styrene and having a solid content of 50% by weight.

This microcapsule-type adhesive was coated on both sides of the laminated sheet using a kiss coater and dried at 80° C. for 20 minutes to form a microcapsule-type transparent pressure-sensitive adhesive layer with a thickness of 10 μm.

In this way, an adhesive sheet for postcards of the present invention was obtained, which consisted of a pressure-sensitive adhesive layer, a cured resin layer (A), a cured vulcanized rubber layer, and a pressure-sensitive adhesive layer.

Example 4 Using the adhesive sheet for information hiding obtained in Example 3, a postcard specification of the present invention was obtained in the following manner.

That is, in forming the postcard specifications of the present invention, the above-mentioned information-concealing adhesive sheet was interposed between the inner prayer cards formed like double-sided postcards, and the sheet was heated at 5000 g/g at room temperature.
By continuously applying pressure at a rate of 60 mm/min under a pressure of cm2, a postcard specification of the present invention having a secret Wi function was obtained.

This postcard could be easily opened between the transparent curable resin cured 1(A) and the cured vulcanized rubber layer, and the contents (information) of the communication column could be read very easily.

Also, when you open a postcard like this, you can stack it again and heat it.
It was observed that even if pressure was applied, the curable resin cured layer (A) and the vulcanized rubber cured layer were cured or vulcanized, so they did not re-adhere.

By the way, in the present invention, when the adhesive sheet for information hiding is pressurized, the microcapsules are destroyed and adhesive properties are developed. Therefore, when forming a postcard with this sheet interposed, the postcard-like shape can be formed in a short time. Can be reliably adhered to cards of
Therefore, it is recognized that it is possible to improve workability and productivity when manufacturing postcards, further simplifying and rationalizing administrative processes, and to obtain uniform and stable postcards. Ta.

In addition, this pressure-sensitive adhesive layer is formed of microcapsules, and adhesive properties are developed by applying pressure at room temperature, so there is no need to use heating rolls, and the equipment is simple and costs can be reduced.

Furthermore, since this pressure-sensitive adhesive layer is made of microcapsules, there is no risk of blocking and there is no need to use release paper.Therefore, not only is there no waste of resources, but costs can be reduced. .

Example 5 A laminate sheet consisting of a curable resin cured layer (A) and a transparent vulcanized rubber cured layer was obtained in the same manner as in Example 1, and then both sides of this laminate sheet were coated with pressure in the following manner. A transparent pressure-sensitive adhesive layer that exhibits adhesive properties was formed.

That is, a 40% by weight toluene solution of an acrylic adhesive (trade name TD-32, manufactured by Dainippon Ink Co., Ltd.) was used as a pressure-sensitive adhesive layer.
13) Aluminum chelate compound 1 as a hardening agent! ! (trade name TA-101CL manufactured by Dainippon Ink Co., Ltd.) was blended in an apparent weight ratio of 100:2 and further diluted with toluene to a concentration of 33% by weight.

This acrylic adhesive solution was applied to both sides of the laminated sheet using a top reverse coater until the thickness of the adhesive was 1.
It was coated to a thickness of 0 μm and dried at 110° C. for 10 minutes to obtain a double-sided adhesive sheet.

Next, on this solidified surface, a powder made by Nikka Co., Ltd., which is made of edible starch as a fluid powder with non-agglomerated primary particles and whose surface is encapsulated with resin, is applied.
0 was evenly dispersed to make the bonded surface non-adhesive. The amount of spraying was 0.1 g/'m'' to obtain a pressure-sensitive adhesive layer with no surface tack.

Thus, the pressure-sensitive adhesive layer, the curable resin cured layer (!\),
An adhesive sheet for postcards of the present invention comprising a cured vulcanized rubber layer and a pressure-sensitive adhesive layer was obtained.

Example 6 Using the adhesive sheet for information hiding obtained in Example 5, a postcard specification of the present invention was obtained by the following method.

That is, in forming the postcard specifications of the present invention, the above-mentioned information-concealing adhesive sheet was interposed between two postcard-like cards, and the sheet was heated for 60 m at room temperature under a pressure of 5000 g/'c++2. By pressurizing at a rate of 1/min, a postcard specification of the present invention having a secretion capacity of 1 sheet was obtained.

This postcard specification could be easily opened between the transparent curable resin cured layer (A) and the transparent vulcanized rubber cured layer, and the contents (information) of the communication column could be read extremely easily.

Also, when you open a postcard like this, you can stack it again and heat it.
Even when pressurized, it was observed that re-adhesion did not occur, similar to the case of the above example.

By the way, in the present invention, when the information-concealing adhesive sheet is pressurized, the barrier layer is destroyed and adhesive properties are developed. Therefore, when forming a postcard with this sheet interposed, the postcard-like shape can be formed in a short time. It can be layered securely with other cards, which can significantly improve workability and productivity when manufacturing postcards, simplifying and rationalizing administrative processes, and ensuring uniform and stable production. It was recognized that it was possible to obtain postcards.

Furthermore, since the surface of this pressure-sensitive adhesive layer is covered with a barrier layer, there is no risk of blocking and there is no need to use release paper, so not only is there no waste of resources, but
It is possible to reduce costs.

(g) Effect of the invention The information hiding adhesive sheet of the invention has the above configuration,
Ordinary postcard-like [This can be stacked with formed cards or products, or stacked in sheet form that has been heated with Humbuter and heated and pressurized, and used for various purposes such as postcards and labels with secret functions. be done.

The adherend itself of this information-concealing adhesive sheet has a concealing power, and confidential information such as communication columns on the inner surface cannot be read from the outside.

For example, when the recipient of a postcard, etc. (adherend) formed using this information-concealing adhesive sheet takes the postcard, etc. and opens it, the real melt in the information-concealing adhesive sheet on the postcard, etc. The layer or pressure-sensitive adhesive layer and the adherend are firmly adhered, while there is a temporary bond between the transparent curable resin cured layer and the transparent synthetic resin layer or the transparent vulcanized rubber cured layer of the adhesive sheet for information hiding. Since it is glued, it can be opened relatively easily at that point, allowing the recipient of the postcard etc. to easily read the contents of the confidential information.

Furthermore, once a postcard or the like is opened at the above-mentioned location, the curable resin or vulcanized rubber has already been hardened or vulcanized, so even if they are stacked again and heated and pressurized, they will not be re-adhered.

In this way, if a postcard, etc. is opened once and cannot be re-attached, it is extremely easy to identify the person who intervened between the time the postcard, etc. was sent and the time it was handed over to the person who received it. This has the effect that there is no need for anyone to open it, and personal safety equipment is reliably protected.

Furthermore, since postcards, etc. cannot be opened without permission, there is an effect that accidents such as rewriting or writing of confidential information in the communication section of postcards, etc., do not occur.

By the way, in the present invention, since the curable resin or vulcanized rubber in the adhesive sheet for information hiding is cured or vulcanized in advance, the curable resin or vulcanized rubber is not cured or vulcanized when forming postcards, etc. There is no need to overlay the sheet and the adherend to develop the adhesiveness of the hot melt layer, or alternatively, the sheet and the adherend can be overlapped and pressure is applied to develop the adhesiveness of the pressure-sensitive adhesive layer. Therefore, when the card and the adherend are overlapped and bonded, this bonding can be done reliably in a short time, significantly improving work efficiency and productivity, simplifying administrative processing. In addition to being able to streamline the process, it also has the effect of producing postcards, etc. that are homogeneous and stable.

Furthermore, the hot-melt layer or pressure-sensitive adhesive layer in the information-hiding adhesive sheet of the present invention can be prevented from blocking by micro-encapsulating the adhesive or forming a glossy layer on the surface of the adhesive layer if necessary. Because it is so small, there is no need for release paper, so not only is there no waste of resources, but costs can also be reduced.

The information concealing adhesive sheet of the present invention can be used not only as a means of communication with a secret function such as by mail or in-house mail, but also as a label attached to a product or information that should be kept confidential in the trading world, such as the burden of a product. Information about sales is extremely useful as a means of hiding information such as prizes and other items by pasting them on the product.

Claims (12)

[Claims] (1) A transparent synthetic resin layer (C) is formed on one side of the transparent curable resin cured layer (A) or the vulcanized rubber cured layer (B), and a transparent hot melt layer is formed on the other side. , and an information-hiding adhesive sheet comprising a transparent hot melt layer formed on the exposed surface of the synthetic resin layer. (2) The adhesive sheet for information hiding according to claim 1, wherein the transparent synthetic resin layer (C) is a transparent thermoplastic resin layer. (3) The transparent synthetic resin layer (C) is a transparent curable resin cured layer (A_
1) The adhesive sheet for information hiding according to claim 1. (4) In the information hiding adhesive sheet of claim 1, in place of the transparent synthetic resin layer (C), a transparent vulcanized rubber cured layer (B_1) of a different type from the transparent vulcanized rubber cured layer (B) )
An adhesive sheet for information hiding. (5) In the adhesive sheet for information hiding according to claim 3, a transparent vulcanized rubber cured layer is formed in place of either one of the bicurable resin cured layers (A) and (A_1). An adhesive sheet for concealing information. (6) In the adhesive sheet for information hiding according to claim 3, a transparent thermoplastic resin layer is formed in place of either one of the bicurable resin cured layers (A) and (A_1). Adhesive sheet for information hiding. (7) In the adhesive sheet for information hiding according to any one of claims 1 to 6, the hot melt layer has a density of 40 to 100.
An adhesive sheet for information hiding that exhibits adhesive properties at ℃. (8) In the information-hiding adhesive sheet according to any one of claims 1 to 7, in place of the hot-melt layer on at least one side of the hot-melt layers on both sides, a transparent adhesive sheet that develops adhesive properties under pressure is used. An information-hiding adhesive sheet formed with a pressure-sensitive adhesive layer. (9) The adhesive sheet for information hiding according to claim 8, wherein the pressure-sensitive adhesive layer exhibits adhesive properties by breaking microcapsules under pressure. (10) The adhesive sheet for information hiding according to claim 8, wherein the pressure-sensitive adhesive layer exhibits adhesive properties by destruction of the barrier layer by pressure. (11) A postcard specification in which the information-concealing adhesive sheet according to any one of claims 1 to 10 is interposed between and adhered to two cards shaped like a postcard. (12) A postcard specification in which the information-concealing adhesive sheet according to any one of claims 1 to 10 is interposed between and adhered to a center-folding card shaped like a return postcard.