JPH04189194A - Adhesive sheet for concealing information and specifications of postcard formed using same sheet - Google Patents

Abstract

PURPOSE:To protect privacy such as of an individual by laminating a transparent hot melt layer on the exposed surface of a mold lubricant-treated curable layer formed on the one surface of a concealing sheet. CONSTITUTION:A mold lubricant-treated curable layer is formed on the one surface of a concealing sheet, and a transparent hot melt layer is laminated on the exposed surface of the mold lubricant-treated curable layer of said sheet. The recommended thickness of the concealing sheet is about 6 to 250mum, and also the recommended thickness of the mold lubricant-treated curable layer is about 0.05 to 3mum. In addition, the recommended hot melt layer used should be capable of becoming adhesive at about 130 deg.C normally. Further, the recommended thickness of the hot melt layer is about 0.1 to 50mum. Thus it is possible to ensure that information contained in a postcard can be made secret.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention is applicable to applications such as national pension payment notices, employee pension payment notices, deposit balances, securities transactions, etc., which are displayed using characters, symbols, figures, photographs, etc. Concealing private information that you do not want others to know, such as contents, disease diagnosis results, or information that should be kept confidential in the business world, such as information on bargain sales of products, lottery tickets, prizes, and sweepstakes, etc. This product relates to an adhesive sheet for concealing information, which is used to convey information and to simplify and streamline administrative processes.

(b) Prior Art Recently, it has been practiced to hide information generated by a computer and to transmit this information from a specific person to another specific person for use.

Examples of means of this communication include mail, internal mail, etc.

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

Furthermore, with conventional postcards, the contents of the communication column may become smeared or blurred and become unclear between the time the letter is posted in the mailbox and the addressee picks up the post.

For this reason, for example, specific notices that should be kept confidential, such as national pension payment details, employee pension payment details, information on product burden sales, 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, it is usually sent in a sealed letter at the sender's discretion.

However, when making sealed letters in this way, unnecessary work such as inserting documents into envelopes and gluing them is required, which makes the work less efficient, and the postage costs are significantly higher than for postcards, making it uneconomical. There were some drawbacks.

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).

In other words, ■ a transparent protective film made of thermoplastic resin that is adhered to the back side of the postcard, a cover sheet with concealing properties laminated with a thermoplastic resin film on the back side, and a thermoplastic resin film of the same type as the resin film. A postcard with a sticker has been proposed, which is made of a plastic 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.
3-6870).

In addition, ■a transparent thermoplastic resin protective film that is adhered to the back side of a postcard that has been printed using computer processing, and a concealable cover that is laminated with a thermoplastic resin film on the back side. A postcard comprising a sheet and a bonding layer made of a thermoplastic resin of the same type as the resin film and thermally extruded at a temperature lower than the melting point of the resin to releasably bond the protective film and the cover sheet. It has been proposed (Utility Model No. 63-11863)
Publication No.).

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 (■), both films to be adhered to each other are heated using thermoplastic resin of the same type in the areas where they are to be firmly adhered and cannot be peeled off. , which are integrated when pressurized, while the parts that can be easily peeled off, that is, the parts where the postcard can be opened, are made by temporarily adhering both films to each other using thermoplastic resins of different types. However, since these materials are made of thermoplastic resin, they temporarily adhere again when heated and pressed with an iron or the like after the postcard is opened, so the important problem described below remains.

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, in the label sheet (2) above, the adhesive has tackiness, and a release paper is pasted on the adhesive-coated surface to protect the surface or improve handleability. 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 consumption 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.

Further, 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 also there is a problem that if the release paper is thrown away as garbage, it will cost a considerable amount of money to dispose of it.

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, and by interposing a release-treated cured layer as an intermediate layer in a laminated sheet in which a concealing sheet is essential, the release-treated cured layer can be peeled off at the location of the release-treated cured layer. To provide an adhesive sheet for information hiding, which eliminates the need for release paper and eliminates waste of resources by using a hot melt layer or a pressure-sensitive adhesive layer that develops adhesive properties by applying pressure as an adhesive layer. With the goal.

Incidentally, in the present invention, the release-treated hardened layer is used because once the postcard, etc. is opened, it cannot be re-adhered, and there is no need for any person to intervene in opening the postcard, etc. from shipping to handing it to the person. This is because it is extremely easy to identify whether the person has sent a postcard or the like, and therefore no one opens postcards without permission, and the privacy of individuals is reliably protected.

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

That is, in the information-concealing adhesive sheet of this aMyIc section 1, a mold release treatment cured layer is formed on one side of the concealment sheet, and a transparent hot-melt layer is formed on the exposed surface of the template disposal layer in this treatment sheet. An adhesive sheet for information hiding made of laminated layers.

In the information-concealing adhesive sheet of this 1ipv requirement 2, the information-concealing adhesive sheet has a base sheet and a thermoplastic d (fat layer, curable resin cured layer, vulcanized rubber cured layer). Alternatively, it is formed of a laminated sheet made of gold R foil.

In the information-concealing adhesive sheet of claim 3 of the present application, a release-treated cured layer is formed on one side of the concealing sheet, and a transparent synthetic resin layer is laminated on the release-treated cured layer of this treated sheet, A transparent hot melt layer is laminated on the exposed surface of the synthetic resin layer.

In the information hiding adhesive sheet of this IIM requirement 4,
In the information-hiding adhesive sheet, the transparent synthetic resin layer is a transparent thermoplastic resin layer or a curable resin cured layer.

In the information hiding adhesive sheet according to claim 5, in place of the transparent synthetic resin layer in the information hiding adhesive sheet, a transparent cured vulcanized rubber layer is laminated.

In the adhesive sheet for information hiding according to claim 6,
In the above-mentioned adhesive sheet for information hiding, -1) E7) The melt layer exhibits adhesiveness at 40 to 100°C.

In the information-hiding adhesive sheet according to claim 7, in place of the above-mentioned information-hiding adhesive sheet, the transparent hot-melt layer is replaced with a transparent pressure-sensitive layer that develops adhesive properties when pressure is applied. It is made by laminating adhesive layers.

The adhesive sheet for information hiding according to claim 8 of the present application has the following features:
In the information-hiding adhesive sheet, the transparent pressure-sensitive adhesive layer exhibits adhesive properties when the microcapsules are destroyed by pressure.

In the information-concealing adhesive sheet according to claim 9 of the present application, the transparent pressure-sensitive adhesive layer of the information-concealing adhesive sheet exhibits adhesive properties when the barrier layer is destroyed by pressure.

In the postcard specification of claim 10, the above-mentioned information-concealing adhesive sheet is laminated and adhered to one card shaped like a postcard.

Hereinafter, first, an information-concealing adhesive sheet in which a pattern-treated cured layer is interposed between a concealing sheet and a transparent hot-melt layer will be described in detail.

The concealable sheet used in the present invention is not particularly limited as long as it is formed of a sheet-like material in which information such as characters and figures from the front side to the back side cannot be seen.

Specifically, examples include a concealing sheet made of paper (including synthetic paper; the same shall apply hereinafter) or synthetic resin, or a concealing sheet formed by vulcanizing concealing vulcanized rubber. .

The thickness of this concealing sheet is not particularly limited as long as it has enough strength not to be damaged when peeled off at the part of the mold release cured layer described below, but it is generally 6 to 250 μ-1. In particular, it is desirable to have a thickness in the range of 12 to 50 .mu.m. If the thickness is less than 6 .mu.m, there will be problems in strength and handleability, while if it exceeds 250 .mu.m, it will be heavy and uneconomical.

In the present invention, a mold release treatment cured layer is applied to one side of the above-mentioned concealing sheet. The processing agent is not particularly limited as long as it is cured by heat, ultraviolet rays, or electron beams.

In this way, if a hardening type is used as the template processing agent, and it is formed on one side of the above-mentioned concealing sheet in advance and cured to form a release treatment hardened layer, the postcard Even if they are opened and then stacked again under heat and pressure, the cured release layer prevents them from being re-adhered.

In addition, this release-treated cured layer is generally transparent, but it must be transparent when it is peeled off on the side opposite to the concealing sheet side, for example, between the template-treated cured layer and the transparent synthetic resin layer. does not require

By the way, in the present invention, when the template processing agent does not have crosslinking properties, the template processing agent may exhibit crosslinking properties and be cured by adding a chemical crosslinking agent to the template processing agent. As this chemical crosslinking agent, known ones can be mentioned. The blending ratio of this chemical crosslinking agent is in the range of 0.5 to 10 parts by weight per 100 parts by weight of the mold release treatment agent, and if the blending ratio of the chemical crosslinking agent is less than 0.5 parts by weight, sufficient curing is not achieved. If a layer is not obtained and it is opened once at the relevant point and then layered again and heated and pressurized, there is a risk of re-adhesion.On the other hand, if the amount exceeds 10 parts by weight, visibility will not only decrease, but also the product value will decrease.
Therefore, it is particularly desirable to use 1 to 3 parts by weight.

Specifically, examples of the curing mold release agent include ether copolymers such as long-chain alkyl acrylate copolymers, long-chain alkyl vinyl esters, and long-chain alkyl vinyl ether copolymers, and dimethylsiloxane copolymers. Rubber (
Containing silicone-based phenylmethylsiloxane), long-chain alkyl acrylamide copolymers, etc., silicone-based, chromium-containing compounds (US
P2803557, USP3236677), copolymers of long-chain alkyl maleic acid derivatives,
Copolymers of long chain alkyl allyl esters, long chain alkyl esterification of polymers, long chain alkyl carbamates of polymers, polyethyleneimine derivatives, polyvinyl alcohol alkyl diincyanates, compounds containing perfluorinated alkyl groups, long chain alkyl compounds and polymers. There are mixtures, low-adhesive polymers that do not contain long-chain alkyl groups, etc., but in general, long-chain alkyl vinyl ether copolymers, trimethylsiloxane copolymer rubber (containing silicone-based phenylmethylsiloxane), and ultraviolet-curable silicone foams are available. Limer (dimethylpolysiloxane containing epoxy groups, such as manufactured by Toshiba Silicone Co., Ltd., product name UV9300, U
Silicone-based materials such as V9305 or mixtures thereof, polyvinyl alcohol alkyl diincyanate, and long-chain alkyl acrylate copolymers are preferred from the viewpoint of ease of handling, appropriate adhesion/peelability, and transparency. If desired, a chemical crosslinking agent may be added to these mold release agents.

In the present invention, when forming a mold release treatment cured layer on one side of the above-mentioned concealing sheet using the above-mentioned curing type processing agent, an appropriate method such as a coating method or a spraying method is used as necessary to form the one-side surface. can be selected and adopted.

Further, the thickness of this mold release treatment hardened layer is not particularly limited, but is generally 0.05 to 3 μl, particularly 0.5 to 2 μl.
It is desirable that the thickness be within the range of 0.05 μm.
If the thickness is less than 3 μm, the releasability may deteriorate, while if the thickness exceeds 3 μm, the adhesive strength may decrease and it may be difficult to adhere to the hot melt layer, which is also uneconomical.

In the present invention, a transparent hot melt layer is laminated on the mold release cured layer of the treated sheet.

The transparent hot-melt layer used in the present invention is one that melts at a temperature below the deterioration/deformation temperature of the above-mentioned concealing sheet and exhibits adhesive properties, and also firmly adheres to postcard-like cards, etc., which will be described later. Although not particularly limited, it is generally preferable to use a material that exhibits adhesive properties at a temperature of 130° C. or lower.

Specific examples of this transparent hot melt layer include saturated polyester resins, polyamide resins, cellulose resins, polyacetal resins, etc. In addition to those that exhibit hot melt properties by themselves, they are generally used in combination with tackifiers, plasticizers, etc. These include various rubbery polymers such as nitrile rubber, which has a large amount of nitrile rubber, and various polymers such as ethylene-vinyl acetate copolymer. 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 it is generally desirable to be in the range of 0.1 to 50 μm, especially 1 to 5 μm; if this thickness is less than 0.1 μm, the desired There is a risk that adhesive strength may not be obtained;
If it exceeds m, there will be problems with transparency, and it will be heavy and 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 this 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.

In this way, in the present invention, the adhesive sheet for information hiding is formed by interposing the mold release cured layer between the hiding sheet and the transparent hot melt layer. It is possible to significantly improve the workability and productivity when manufacturing products, etc., simplifying and rationalizing administrative processes, and also making it possible to obtain uniform and stable postcards. Since bronking is suppressed in the melt layer, there is no need to use a release paper, so not only is there no waste of resources, but costs can be reduced.

By the way, in the present invention, a curable type is used as the pattern processing agent, and if this is formed on one side of the concealing sheet in advance and cured to form a release processing hardened layer, the pattern processing agent will be cured at the part of the pattern processing hardened layer. Postcards and the like are easy to open, and if they are opened at the part of the release-treated hardened layer, even if they are stacked again and heated and pressurized, this part will be hardened and will not be re-adhered.

If re-adhesion is not possible in this way, it will be extremely easy to determine what kind of people were involved between the sender and the recipient of the postcard or product, so no one will open the postcard without permission, and the information will remain confidential. This will ensure that gender is more securely protected.

Next, another information-covering adhesive sheet of the present invention will be explained.

That is, in the present invention, it is also useful that the concealing sheet is formed of a laminated sheet consisting of a base sheet, a thermoplastic resin layer, a curable resin layer, a vulcanized rubber layer, or a metal foil.

The base sheet used in the present invention is paper, natural #! Examples include nonwoven fabrics and woven fabrics made of organic fibers such as fibers and synthetic am, and fabrics made of inorganic fibers such as glass fibers.

In the present invention, it is also useful that the concealing sheet is formed of a laminated sheet consisting of the above-mentioned base sheet and a thermoplastic resin layer.

This thermoplastic resin layer is not particularly limited.

Specific representative examples of this thermoplastic ff5R layer include polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinylidene chloride resin, polyamide, polyester, polystyrene, polyurethane, polycarbonate, polyvinyl alcohol, or polyacrylonitrile. In addition to the above, the present invention particularly includes synthetic rubbers such as polybutanoene and polyisoprene. In this case, if it is necessary to impart hiding properties to these resins or rubbers, it is sufficient to add a known inorganic or organic nine-term agent, pigment, etc. to ensure the hiding properties.

The thermoplastic resin layer may be formed on the base sheet using a known method such as a coating method or a spreading method.

The thickness of this thermoplastic resin layer is not particularly limited, but the thickness of the thermoplastic resin layer is 0.1 to 100 μm, particularly 0.1 to 5 μm.
．． It is desirable that the thickness be in the range of 0.mu.-.
If the thickness is less than 1 μm, it is difficult to form a uniform layer and there is no point. On the other hand, if it exceeds 10,077 m, it becomes heavy and uneconomical.

In the present invention, as the concealing sheet, one formed of a laminated sheet consisting of the above-mentioned base sheet and a curable resin cured layer is also suitably used.

- The cured layer of the mud-forming resin is not particularly limited as long as it is cured by heat, ultraviolet rays, electron beams, moisture, or the like.

The formation of this curable resin cured layer is not particularly limited, but for example, a solution of the curable resin is first cast on the base sheet, or the curable resin is coated on the base sheet. Examples include a method in which the adhesive is formed on the surface by a spraying method or the like, and then cured by heat, ultraviolet rays, electron beams, moisture, or the like.

Typical examples of the curable resin used in the present invention include epoxy resin, unsaturated polyester resin,
Phenol resin, diallyl phthalate resin, thermosetting polyurethane resin, ultraviolet curable polyurethane resin, moisture curable polyurethane resin, electron beam curable polyurethane resin, silicone resin, alkyd resin, etc. From the viewpoint of flexibility, thermosetting polyurethane resin, ultraviolet curable polyurethane resin, moisture curable polyurethane resin, electron beam curable polyethylene a
T-fats, epoxy resins, unsaturated polyester resins, etc. are preferable. In this case, when it is necessary to impart hiding properties to these resins, known inorganic or organic fillers and pigments are added to ensure the hiding properties.

When forming this curable resin cured layer, it is possible to contain additives such as a curing agent and a curing catalyst that correspond to the curable resin used. In this case, 100 parts by weight of thermosetting 0J resin On the other hand, it is desirable that the additive amount be 0.1 to 30 parts by weight.

The thickness of this curable resin cured layer is not particularly limited, but is generally 0.1 to 100 μm, particularly 0.1 to 5 μm.
．． It is desirable that the thickness is in the range of 0 μm.
If it is less than 1 .mu.m, it is difficult to form a uniform layer and there is no point. On the other hand, if it exceeds 100 .mu.m, it becomes heavy and uneconomical.

In this way, since the curable resin is cured in advance to form a curable resin cured layer, if a postcard, etc. is opened at the part of the release-treated cured layer, it will not be possible to re-adhere it even if heated and pressurized again. It is.

In the present invention, as the concealing sheet, one formed of a laminated sheet consisting of the above-mentioned base sheet and a cured layer of vulcanized rubber is also suitably used.

The vulcanized rubber cured layer used in the present invention is first formed by forming a solution of vulcanized rubber on one side of the base sheet and heating and vulcanizing it, or a mixture of raw rubber containing a vulcanizing agent. There is no particular limitation as long as the material is formed into a sheet, which is formed on one side of the base sheet, and then heated and vulcanized.

Examples of the cured vulcanized rubber layer used in the present invention include those having a molecular weight of 100,000 to 1,000,000 and having rubber elasticity and containing a vulcanizing agent. Specifically, for example, homopolymers such as natural rubber, acrylic rubber, acrylonitrile rubber, nitrile rubber, styrene rubber, styrene-butane rubber, butadiene rubber, imprene rubber, chloroprene rubber, butyl rubber, or vinyl chloride, or two of these.
Examples include copolymers of more than one species, and mixtures of two or more thereof. Also, known vulcanizing agents can be used as the vulcanizing agent. In this case, when it is necessary to impart hiding properties to these resins, known inorganic or organic fillers and pigments are added to ensure the hiding properties.

Further, the thickness of this vulcanized rubber cured layer is not particularly limited, but is generally 0.1 to 100μ, particularly 1 to 5μ.
If the thickness is less than 0.1 μm, a uniform thin film may not be obtained and the quality may become unstable, while if it exceeds 100 μm, problems may occur with transparency. , it becomes heavy and uneconomical.

In the present invention, as the concealing sheet, one formed of a laminated sheet consisting of the above-mentioned base sheet and metal foil is also suitably used.

The metal foil used in the uniform is not particularly limited, but aluminum, zinc, and copper are particularly desirable because they have a beautiful appearance and are easy to manufacture by vapor deposition, lamination, or the like.

The thickness of this metal foil is not particularly limited, but it is generally desirable to range from 0.1 to 100 μm, particularly from 1 to 20 μm; if the thickness is less than 0.1 μm, a uniform thin film cannot be obtained. There is a risk that the quality may become unstable.
On the other hand, if it exceeds 100/Jm, it becomes heavy and uneconomical.

Specific examples of the concealing sheet used in the present invention include a sheet of paper laminated with aluminum foil, zinc foil, or copper foil on one side, a sheet of paper with aluminum vapor-deposited on one side, and a sheet of paper with synthetic resin, etc. An example is a sheet laminated with a film manufactured by.

Examples of the synthetic resins include cellulose acetate, cellulose triacetate, fluororesin, polycarbonate, aromatic or aliphatic polyamide, polysulfone, polyethylene, polypropylene, polyester, polyvinyl alcohol polyimide, polyurethane, hydrochloric acid rubber, polyphenylene oxide, Examples include polyphenylene sulfide, polyamideimide, bismaleimide/triazine, epoxy 8 (fat), polyamide/bismaleimide, polyacetal, polyetheretherketone, polyneethylsulfone, polyarylate, polyoxybenzoyl, or the above-mentioned synthetic rubbers. In order to impart hiding properties to this synthetic resin, etc., it is necessary to add well-known solid or organic fillers and pigments to ensure hiding properties, or to add aluminum to one side of the sheet formed from the above synthetic resin. Examples include laminating foil to ensure concealment, or ν1, depositing aluminum on one side of a sheet made of the above-mentioned synthetic resin to ensure concealment. From the viewpoints of performance and aesthetics, it is desirable to use a sheet of paper with aluminum foil laminated on one side, or a sheet of paper with aluminum vapor-deposited on one side.

In the present invention, a transparent hot melt layer is laminated on the above-mentioned concealing sheet (with a mold release treatment cured layer interposed therebetween).

In this case, the material, forming method, etc. of the mold release cured layer and hot melt layer are the same as those described above.

With this configuration, the same effects as in the above case can be obtained in the present invention.

In particular, in the present invention, since the concealing sheet is reinforced with the base sheet, it is even less likely to be damaged when peeled off.

In the information-concealing adhesive sheet of the present invention, a release-treated cured layer is formed on one side of the concealable sheet, and one transparent synthetic resin layer is laminated on the template-treated cured layer of this treated sheet, It is also useful to have a transparent hot melt layer laminated on one side of the synthetic resin layer.

This information-concealing adhesive sheet is formed by interposing a transparent synthetic resin layer between the release-treated cured layer and the transparent hot-melt layer in the information-concealing adhesive sheet described above. The adhesive sheet, template treated hardened layer, and hot melt layer are the same as those described above, and therefore will be omitted.

In addition, as the transparent synthetic resin layer used in the second invention,
It may be either a thermoplastic resin layer or a curable resin cured layer, and is not particularly limited.

As this thermoplastic resin layer or curable resin cured layer, one formed of the above-mentioned thermoplastic resin or curable resin can be used, but since these need to be transparent, this point should be taken into consideration. It is necessary to select synthetic resin.

As a method for forming this transparent synthetic resin layer, the above-mentioned method may be adopted as appropriate.

Further, the thickness of this combined r&resin layer is not particularly limited, but is 0.1 to 100 μI, particularly 0.

It is desirable to set it as the range of 1-5.0 micrometers.

In other words, the purpose of forming a transparent synthetic resin layer in this way is to ensure surface smoothness and further increase transparency.
This thickness is to make it easier to decipher the zygote information.
If the thickness is less than 0.1 μm, a uniform layer cannot be formed, which may reduce the surface smoothness and cause diffuse reflection of light.
There is a risk that the desired transparency may not be obtained;
If it exceeds I11, it becomes too thick, causing problems with transparency, becoming heavy, and being uneconomical.

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.

The information hiding adhesive sheet of the present invention is advantageously obtained by laminating a transparent cured vulcanized rubber layer in place of the synthetic resin layer in the information hiding adhesive sheet described above.

This information-hiding adhesive sheet has a transparent vulcanized rubber cured layer laminated in place of the synthetic resin layer in the information-hiding adhesive sheet. Therefore, the concealing sheet, template-treated cured layer, and hot melt layer are the same as those described above. This is omitted as it is the same as the above.

Furthermore, as the transparent cured rubber layer used in this invention, one formed of the above-mentioned vulcanized rubber can be used, but since it is required to be transparent, this point is taken into account when using vulcanized rubber. need to be selected.

As a method for forming this transparent cured vulcanized rubber layer, the above-mentioned method may be adopted as appropriate.

Further, the thickness of this vulcanized rubber cured layer is not particularly limited, but is generally 0.1 to 100μ, particularly 0.1 to 5.
A range of 0 μm is desirable.

That is, the purpose of forming such a transparent cured vulcanized rubber layer is to ensure surface smoothness and further increase transparency, thereby making it easier to decipher confidential information. If it is less than .1 μm, a uniform layer cannot be formed, so the surface smoothness may decrease and 6L reflection of light may occur, and as a result, the desired transparency may not be obtained.
If it exceeds 0 μm, it becomes too thick, causing problems in transparency, and is also heavy and uneconomical.

Since the information-hiding adhesive sheet of the present invention has the above configuration, in addition to the effects of the information-hiding adhesive sheet described above, surface smoothness is ensured by the formation of a transparent cured vulcanized rubber layer. This makes it even more transparent, making it easier to decipher 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 a temperature of 40 to 100°C.

In other words, this information-concealing adhesive sheet hides information printed on a computer, etc., and aims to simplify and speed up office processing, but if the melting point of the true melt layer is too high, it will cause problems as described below. Adhesiveness and adhesion speed to postcard-like cards are issues, and the heat capacity of the processing equipment is particularly important. For this reason, it is desirable that the temperature at which the true-melt layer exhibits adhesive properties is as low as possible. If the temperature at which the true 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 it exceeds 100°C, problems may occur in terms of adhesiveness and adhesion speed, etc. , 8H! to further simplify and speed up administrative processing! may occur.

By the way, this hot melt layer has an angle of 40 to 100 degrees.
There is no particular limitation as long as C exhibits adhesive properties, and this true melt layer is selected and used from the above.

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

By configuring in this way, in addition to the above-mentioned effects,
This is extremely beneficial as it can further simplify and speed up administrative processing.

In the present invention, in the above-mentioned information-hiding adhesive sheet, it is also useful to have a laminated transparent pressure-sensitive adhesive layer that exhibits adhesive properties when pressed, instead of the transparent hot-melt layer.

Examples of this transparent pressure-sensitive adhesive layer include those whose adhesive properties are developed by the destruction of microcapsules under pressure.

Specifically, for example, microcapsules filled with an adhesive can be fixed to one side of an adhesive sheet for information hiding, and this fixing method involves heating the sheet to partially melt it. Adhesion can be achieved by a method such as spraying microcapsules on top.

It is also advantageous for the pressure-sensitive adhesive layer to develop adhesiveness by destroying the barrier layer under pressure, instead of developing adhesiveness by destroying the microcapsules.

This adhesive layer is formed on both sides of an adhesive sheet for information hiding, and fine starch powder or fine powder of thermoplastic resin such as polyethylene is sprinkled on the surface of each adhesive layer, or alkylphenol or xylene resin, etc. What is necessary is to form a barrier layer consisting of a diaphragm 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 (neoprene) 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 microcapsule layer and adhesive layer is 3~
A thickness of 50 μm, particularly in the range of 5 to 20 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, so it is not preferable.
On the other hand, if it exceeds 50 μm, it is undesirable because it becomes heavy and the sheet becomes thick, making it difficult to handle and 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. This not only significantly improves workability and productivity during production, but also enables the production of homogeneous and stable products.

In addition, since the pressure-sensitive adhesive layer used here contains a pressure-sensitive adhesive that is microencapsulated or a barrier layer is formed on the surface of the adhesive layer to suppress blocking, a release paper is used as in the case described above. Since this is not necessary, not only is there no wastage of resources, but costs can also be reduced.

By the way, in the present invention, a curable type is used as the mold release agent, and if this is formed on one side of the concealing sheet in advance and cured to form a mold release hardened layer, the mold release hardened layer Postcards, etc. are easy to open at certain points, and if they are opened at the point where the release treatment layer has been cured, even if they are stacked again and heated and pressurized, they will not re-adhere because the release treatment layer has been hardened. .

By the way, it is extremely easy to identify the person who intervened in the process of postcards, products, etc. from the sender to the recipient, so no one will open postcards without permission, and the confidentiality of information will be more securely protected. It will be done.

If desired, various compounding agents such as anti-aging agents, antioxidants, flame retardants, dyes and pigments may be added to the information-hiding adhesive sheet of the present invention.

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 is layered with a card or product normally formed to postcard specifications, or is layered in the form of a computer-printed sheet and heated and pressurized. , used in various applications.

In the postcard specification of the present invention, the information-concealing adhesive sheet is formed by heating and pressing, or by heating and pressurizing the information-hiding adhesive sheet on one card normally formed in the postcard specification. In this case, the postcard specifications include not only normal 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 as high as the adhesiveness of the hot melt layer used and below the deformation/alteration temperature of the concealing sheet, and the pressure condition is 10-100,000 g. /cm
2, especially 100-10000 g/c chain 2 may be used.

In addition, if this pressure condition is less than 10 g/cm2, sufficient adhesion may not be achieved;
It is meaningless if it exceeds ff12.

Furthermore, in the case of a pressure-sensitive adhesive layer, pressure is applied at a pressure higher than the pressure required to develop its adhesive properties, that is, higher than the pressure required to destroy the microcapsules and the barrier layer.

In this case, the pressure conditions are generally 100 to 10,000
00g/c2, especially 2000-100000g/c+
You can do it with o2.

In addition, the adherends used here, such as cards, have the functionality and strength to withstand use as opaque and concealable postcards, labels, etc., and can be printed, written with pens, pencils, etc.
It is not particularly limited as long as it can display symbols, figures, photographs, etc. (Specifically, for example, a sheet made of paper or synthetic resin, or paper impregnated with synthetic resin) Examples include those made by laminating a synthetic resin film on paper, etc. This card may itself have a hiding power, or ν1 may be printed, etc. even if it does not have a hiding power itself. It may also be one that has been given concealing power by.

(e) Effect For information hiding of the present invention! I-adhesive sheets have the above-mentioned structure and can be used for various purposes by stacking them on cards or products that are usually formed into postcards, or by stacking them in the form of a computer-printed sheet and heating and pressurizing them. used in

This adhesive sheet for information hiding has a hiding power on the adherend such as a card, and confidential information such as communication fields on the inside cannot be read from the outside. When a recipient of a postcard, etc. (adherent) formed using a postcard, etc., takes the postcard, etc. without force and opens it, the hot melt layer or pressure-sensitive adhesive layer of the adhesive sheet for information concealment on the postcard, etc. adheres. The body is firmly adhered, and on the other hand, the template-treated hardened layer of the adhesive sheet for information concealment is moderately temporarily adhered, so it can be removed relatively easily at that point.
This allows the recipient of the postcard, etc., to easily read the contents of the confidential information.

By the way, in the present invention, a hardening type is used as the mold release agent, and if this is formed in advance by forming the concealing sheet 12 and hardening it, then forming an r+a type hardening layer, the second mold release treatment hardening is performed. It is easy to force the postcard to open at the layer location, and if it is opened at the location where the release treatment cured layer is applied, even if it is stacked again and heated and pressurized, the release treatment layer will be hardened and bonded again. It has a difficult effect.

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 was sent and the time it was handed over to the person in question. etc., open <A, 7! LFU will be eliminated, and the privacy of individuals will be more securely protected.

In addition, since postcards cannot be opened without permission, accidents such as rewriting or writing of the contents of the communication column on postcards, etc. may occur.

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

In particular, if a pressure-sensitive adhesive layer that develops adhesive properties by pressure is formed in place of the hot-melt layer of the information-concealing adhesive sheet of the present invention, when forming postcards etc. It is possible to bond two-liquid adherends continuously while applying pressure with a roll, which eliminates the need for heating means, which simplifies equipment, and improves workability and productivity when adhering to adherends. It is possible to significantly improve the quality of the product, and to obtain a homogeneous and stable product.

Then, according to the postcard specifications of the present invention (first, the above-mentioned information-concealing adhesive sheet is layered on one card normally formed to postcard specifications and heated and pressurized, or continuously It has the ability to hide information and simplify and speed 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 A sheet made of paper laminated with aluminum (thickness: 25 μL11) was used as an opaque sheet, and a transparent cured release layer was formed on the aluminum side surface of the opaque sheet by the following method.

That is, 99% by weight of UV-93'OO manufactured by GE, which is trimethylpolysiloxane containing an epoxy group.
As a curing catalyst, 1% of onium salt photopolymerization catalyst, trade name 9310C manufactured by GE Corporation, was added and mixed until homogeneous, which was used as an ultraviolet #X (U■) curing type mold release agent. The treatment was performed using a three-roll offset gravure machine, which is commonly used as a 100% solvent-free silicone coating system, to a thickness of about 0.5μ, and was applied to the aluminum side of the opaque sheet. and curing was performed by U-irradiation.

The UV irradiation conditions were 80 W using a high pressure mercury lamp.
Irradiation was performed from a height of 10 cm at a line speed of 81,3 mJ/cm' at a line speed of 5III/cm.
Created under the following conditions.

This treated sheet had a uniform pattern-treated surface, and the release-treated cured layer was adhered to the aluminum surface of the concealing sheet.

Next, a true melt layer was formed on the exposed surface of the template treated cured layer in this treated sheet by the method described below.

That is, as the true melt layer, E manufactured by Chevron Chemical Co.
MA (ethylene methyl acrylate) with a methyl acrylate content of 33% by weight, trade name DS1009/2 (melting point 57°C, softening point 23°C) was used at a temperature of 1 using the T Gouy method.
It was extruded at 50'C to obtain a 10 μm thick film, which was laminated via a cooling roll.

In this way, an information-hiding adhesive sheet of the present invention was obtained, in which a transparent release-treated cured layer was interposed between the concealing sheet and the transparent true-melt layer.

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 hot melt layer side of the adhesive sheet for information concealment and a card formed in the shape of a postcard were stacked together with a pressure roll at 50°C. 60 m/ under pressure of 1000 H/ca+”
By continuously heating and pressurizing the material in minutes, a postcard specification of the present invention with a secret function was obtained.

This postcard specification could be easily peeled off by opening the opaque sheet and the transparent cured release layer, making it extremely easy to read the contents (information) in the communication column.

Furthermore, when the postcards were opened in this way, it was found that since the release-treated areas had been hardened in advance, they would not be re-adhered even if they were stacked again and heated and pressurized.

By the way, in the present invention, the release treatment layer in the ifC adhesive sheet for information hiding is cured in advance, and only the hot melt layer of the sheet needs to be heated and melted to develop adhesiveness. When stacking this on a postcard-like card to form a postcard, 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 allows for the production of uniform and stable postcards.

Moreover, 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 costs can also be reduced.

Example 3 A laminated sheet consisting of a concealing sheet and a transparent cured release layer was obtained in the same manner as in Example 1, and then a transparent layer that developed adhesive properties by pressure was applied to the exposed surface of the cured release layer. A pressure-sensitive adhesive layer was formed.

That is, as a microcapsule-type adhesive, an acrylic adhesive is prepared by emulsion polymerization using acrylamide as a moamer as a functional group-containing aggregating component whose main monomer is butyl acrylate.

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

This microcapsule-type adhesive was applied onto the release-treated cured layer using a kiss coater and dried at 80'C for 20 minutes to form a microcapsule-type transparent pressure-sensitive liquid N layer with a thickness of 10 μm.

In this way, an information-hiding adhesive sheet of the present invention was obtained, in which a transparent release-treated cured layer was interposed between the concealing sheet and the transparent 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 pressure-sensitive adhesive layer side of the information-concealing adhesive sheet and a card formed like a postcard were stacked together and heated for 5,000 minutes at room temperature.
By continuously pressurizing at 60 m/min under the pressurizing condition of g/cm2, one postcard specification of the present invention having a secret function was obtained.

This postcard specification could be easily opened between the concealing sheet and the transparent cured release layer, making it extremely easy to read the contents (information) in the communication column.

Furthermore, when the postcard specification was opened in this manner, it was found that the concealing sheet and the pattern-treated cured layer did not adhere again even if they were stacked again and heated and pressurized.

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 has been recognized that workability and productivity when manufacturing postcards can be significantly improved, making it possible to further simplify and rationalize administrative processing, and also to obtain uniform and stable postcards. .

In addition, this pressure-sensitive adhesive layer is formed of microcapsules, and exhibits its properties when pressed 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 laminated sheet consisting of a concealing sheet and a transparent cured release layer was obtained in the same manner as in Example 1, and then a transparent layer that developed adhesive properties by pressure was applied to the exposed surface of the cured release layer. A pressure sensitive adhesive layer was formed.

That is, 40 layers of acrylic adhesive as a pressure-sensitive adhesive layer
% toluene solution (trade name TD-32 manufactured by Dainippon Ink Co., Ltd.)
13) was mixed with an aluminum chelate compound (trade name TA-101CL, manufactured by Dainippon Ink Co., Ltd.) as a curing agent at an apparent weight ratio of 100:2, and further 33% by weight of toluene.
A diluted solution was used.

Apply this acrylic adhesive solution to the exposed surface of the transparent mold release cured layer using a top reverse coater until the thickness of the adhesive is 1.
It was coated to a thickness of 0 μm and dried at 110° C. for 10 minutes to obtain a single-sided adhesive sheet.

Next, on this adhesive surface, Nikka Co., Ltd. product name Nikkaliko S, which is a non-agglomerated primary particle and fluid powder mainly composed of edible starch and whose surface is encapsulated with resin, is applied.
The adhesive surface was made non-adhesive by uniformly dispersing -i o o.

The amount of spraying was 0.1 g/m2 to obtain a pressure-sensitive adhesive layer with no surface tack.

In this way, an information-hiding adhesive sheet of the present invention was obtained, in which a transparent release-treated cured layer was interposed between the concealing sheet and the transparent pressure-sensitive adhesive layer.

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 pressure-sensitive adhesive layer side of the information-concealing adhesive sheet and a card formed like a postcard were stacked together and heated for 5,000 minutes at room temperature.
Under pressurized conditions of g/cta2 and 60 IIl/min, a sheet with a secret function is created.
The postcard specifications of the present invention were obtained.

This postcard specification could be easily opened by opening the concealing sheet and the transparent cured release layer, making it extremely easy to read the contents (information) in the communication column.

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 reliably adhered to other cards, and therefore, it can significantly improve the workability and productivity when manufacturing postcards, simplifying and rationalizing administrative processes, and making it possible to produce uniform and stable postcards. It was recognized that it can be obtained.

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 a release paper.Therefore, not only is there no waste of resources, but costs are also reduced. It is possible.

Example 7 A sheet made of paper laminated with aluminum (thickness 25 μm) was used as a concealing sheet, and a silicone-based phenylmethylsiloxane copolymer containing 7.5 mol% of phenylmethylsiloxane was applied to the aluminum side of the concealing sheet. A solution prepared by diluting the combined rubber with toluene to 3% by weight was applied uniformly, and then dried and cured at 100'C for 5 minutes to form a 0.5μ thick, glossy, transparent mold release cured layer. was formed.

On the other hand, to form a transparent cured vulcanized rubber layer, first, acrylic rubber with a molecular weight of 500,000 to 700,000 ``Itagami Kogyo Co., Ltd.'s cleavage product name: Valacron 248E'' was used as a material, and this was dissolved in toluene to give a 10% weight % solution was obtained.

Next, as a vulcanizing agent, incyanate manufactured by Nippon Polyurethane Industries Co., Ltd. (trade name: Furonate) was used, and the solid content was 75%.
% by weight) was added in an amount of 3 parts by weight per 100 parts by weight of the above acrylic rubber (solid content).

Furthermore, a rubber solution containing the above-mentioned vulcanizing agent was uniformly coated on the above-mentioned transparent release-treated cured layer using a kiss coater, and then heated at 120°.
C. for 2 minutes to obtain a transparent cured vulcanized rubber layer with a thickness of 5 .mu.m.

Next, apply eyebrows to the exposed surface of the transparent cured rubber layer.

Each hot melt layer was formed using the method below.

That is, as a resin liquid for forming a hot melt layer,
Polyamide resin “Fuji Kasei Co., Ltd. V product name Tomide #
5 parts by weight of nitrile rubber "Nippon Zeon Co., Ltd. trade name Ninopol 1432JJ" was added to 100 parts by weight of nitrile rubber, and the mixture was diluted to 10% by weight by dissolving it in a 7:3 (volume ratio) solution of toluene and methanol as a solvent. A solution was used.

This solution was uniformly applied to the exposed surface of the cured vulcanized rubber layer and dried at 100° C. for 10 minutes to form a hot melt layer with a thickness of 1.5 μm.

Thus, according to the present invention, a transparent mold release cured layer is formed on one side of a concealing sheet, and a hot melt layer is formed on the mold release cured layer via a transparent vulcanized rubber cured layer. An adhesive sheet for information hiding was obtained.

Example 8 Using the adhesive sheet for information hiding obtained in Example 7, a postcard specification of the present invention was obtained by the following method.

That is, in forming the postcard specifications of the present invention, in the information hiding adhesive sheet, the hot melt layer side and 1
By stacking sheets of postcard-shaped car P and continuously heating and pressurizing them at 1000 g/cm2 (n pressure) with a pressure roll at 50°C at 60 m/min, a single sheet with a secret function is created. The postcard specifications of the present invention were obtained.

This postcard specification can be easily peeled off between the concealing sheet and the transparent cured release layer, and the formation of the transparent cured vulcanized rubber layer ensures surface smoothness, resulting in I was able to easily read the contents (information) of the communication column.

Furthermore, when the postcards were opened in this way, it was found that since the release-treated areas and the vulcanized rubber had been cured in advance, they would not be re-adhered even if they were stacked again and heated and pressurized.

By the way, in the present invention, the release treated area and the vulcanized rubber in the adhesive sheet for information hiding are cured in advance, and it is only necessary to heat and melt only the true melt layer of the sheet to develop adhesiveness. Therefore, when stacking this on a postcard-like card to form a postcard, it can be adhered to the postcard-like card in a short time, improving workability and productivity when manufacturing postcards. In addition to simplifying and rationalizing administrative processes,
It was confirmed that homogeneous and stable postcards could be obtained.

Furthermore, this hot melt layer has no fear of protrusion/king 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 9 As a concealing sheet, a concealing polyester sheet (heat deformation temperature: 242°C, thickness: 25 μla) on which a transparent template-treated cured layer (silicone coat layer thickness: 0.5 μm) was previously formed was used. .

A transparent thermoplastic resin layer made of polycarbonate (heat deformation temperature: 150° C., thickness: 10 μm) was formed on the release-treated cured layer of this treated sheet by a known solution method.

Next, a hot melt layer was formed on the thermoplastic resin layer of this laminate sheet by the following method.

That is, as a resin for forming the HotNol 1 layer, a copolymer consisting of 86% by weight of vinyl chloride, 13% by weight of vinyl acetate, and 1% by weight of maleic anhydride (trade name: VINYL I TE-, manufactured by UCC, USA) was used. VMCHJ carboN-syl group content -0.8% by weight was dissolved in a 1 rl mixed solvent of methyl ethyl ketone and toluene to prepare a solution with a solid content of 5% by weight.

This solvent was uniformly coated on the thermoplastic resin layer of the laminated sheet and dried at 120° C. for 5 minutes to form a hot melt layer with a thickness of 2.5 μI.

Thus, the information hiding method of the present invention is formed by forming a transparent template-treated cured layer on one side of the concealing sheet, and forming a hot-melt layer on the release-treated cured layer via a transparent thermoplastic resin layer. An adhesive sheet for use was obtained.

Example 10 Using the adhesive sheet for information hiding obtained in Example 9, a postcard specification of the present invention was obtained by the following method.

That is, in forming the postcard specifications of the present invention, in the information hiding adhesive sheet, the hot melt layer side and 1
This invention has a single card with a seek function by stacking cards shaped like postcards and continuously heating and pressing them at 60 m/min under a pressure of 1000 B/0 m2 with a pressure roll at 90°C. I got the postcard specifications.

This postcard specification can be easily peeled off by opening the concealing sheet and the transparent template treated hardened layer, and the surface smoothness is ensured by forming a transparent thermoplastic resin layer. I was able to easily read the contents (information) of the communication column.

Furthermore, when the postcards were opened in this way, it was found that since the release-treated areas had been hardened in advance, they would not be re-adhered even if they were stacked again and heated and pressurized.

By the way, in the present invention, the release-treated portion of the adhesive sheet for information hiding is hardened 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 to the postcard-like card reliably 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.

Moreover, 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 costs can also be reduced.

(g) Effect of the invention The information hiding adhesive sheet of the invention has the above configuration,
It is used for a variety of purposes, such as postcards and labels with SeekRef 11 function, by stacking it on cards and products that are usually shaped like postcards, or by stacking them in sheet form that has been punched out with a Humbutter and heating and pressurizing them. Ru.

This information-concealing adhesive sheet has a concealing power itself, and secret information such as the communication column on the inner surface cannot be read from the outside.

For example, when a recipient of a postcard, etc. (adherend) formed using this information-concealing adhesive sheet takes the postcard, etc. and opens it, the transparent information-concealing adhesive sheet on the postcard, etc. The true melt layer or pressure-sensitive adhesive layer and the adherend are firmly adhered, and on the other hand, the adhesive sheet for information hiding is temporarily bonded to the part where the release treatment cured layer is applied, so it can be opened relatively easily at that part. This allows 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 part of the release-treated hardened layer, the hot-melt layer and the release-treated hardened layer do not re-adhere even if they are overlapped 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 was involved in opening the postcard, etc. from the time it was sent until it was handed over to the person in question. This has the effect that the privacy of individuals, etc. is more reliably protected since no one opens the door.

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 template treatment layer, curable resin, or vulcanized rubber in the adhesive sheet for information hiding is cured or vulcanized in advance, when forming postcards, etc., the mold release treatment layer, thermosetting resin, etc. There is no need to heat the resin or vulcanized rubber to cure or vulcanize it, and the sheet and the adherend can be stacked and the hot melt layer melted to develop adhesive properties, or the sheet and the adherend can be bonded together. All you need to do is to stack the cards and apply pressure to develop the adhesive properties of the pressure-sensitive adhesive layer. Therefore, when the card and the adherend are stacked and bonded, this bonding can be done reliably in a short time, making it easy to work. Since efficiency and productivity can be significantly improved, administrative processing can be simplified and rationalized, and it is also possible to obtain uniform and stable postcards.

Furthermore, the hot-melt layer or pressure-sensitive adhesive layer in the information-hiding adhesive sheet of the present invention can microencapsulate the adhesive, form a barrier layer on the surface of the adhesive layer, and further coat the surface of the hot-melt layer with Since blocking is suppressed by forming a barrier layer as necessary, no release paper is required, which not only eliminates wasted resources but also reduces costs.

The adhesive sheet for information concealment of the present invention can be used for mailing, in-house mail, etc.)! In addition to being used as a means of communication with a flexible function, labels attached to products or information that should be kept confidential in the trading world, such as information on product bargain sales, information such as lottery tickets or prizes, etc., can be attached to products. This is extremely useful as a means of concealing the information that is being accessed.

Patent applicant Shinko Kagaku Kogyo Co., Ltd.

Claims (10)

[Claims] (1) Forming a release treatment hardened layer on one side of the concealing sheet,
Further, an information-hiding adhesive sheet is obtained by laminating a transparent hot-melt layer on the exposed surface of the release-treated cured layer in this treated sheet. (2) Adhesive properties for information concealment according to claim 1, wherein the concealing sheet is formed of a laminated sheet consisting of a base sheet and a thermoplastic resin layer, a cured resin layer, a cured vulcanized rubber layer, or a metal foil. sheet. (3) Forming a release treatment hardened layer on one side of the concealing sheet,
Further, an information-concealing adhesive sheet is provided, in which a transparent synthetic resin layer is laminated on the release-treated cured layer of the treated sheet, and a hot melt layer is laminated on the exposed surface of the synthetic resin layer. (4) The adhesive sheet for information hiding according to claim 3, wherein the synthetic resin layer is a transparent thermoplastic resin layer or a curable resin cured layer. (5) The adhesive sheet for information hiding according to claim 3, in which a transparent cured vulcanized rubber layer is laminated in place of the synthetic resin layer. (6) In the adhesive sheet for information hiding according to any one of claims 1 to 5, the transparent hot melt layer has a content of 40 to 40%.
An adhesive sheet for information hiding that exhibits adhesive properties at 100°C. (7) The adhesive sheet for information hiding according to any one of claims 1 to 6, in which, in place of the transparent hot melt layer, a transparent pressure-sensitive adhesive layer that develops adhesive properties when pressed is laminated. Adhesive sheet for information hiding. (8) The adhesive sheet for information hiding according to claim 7, wherein the pressure-sensitive adhesive layer exhibits adhesive properties by breaking microcapsules under pressure. (9) The adhesive sheet for information hiding according to claim 7, wherein the pressure-sensitive adhesive layer exhibits adhesive properties by destruction of the barrier layer by pressure. (10) A postcard specification obtained by laminating and bonding the information-concealing adhesive sheet according to any one of claims 1 to 9 on one card formed like a postcard.