JP3011672B2 - Adhesive sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive sheet which exhibits a pseudo-adhesive property or a non-peelable permanent adhesive property which is temporarily adhered but can be easily peeled off when necessary.

[0002]

2. Description of the Related Art In recent years, the amount of information transmitted through communication means such as communication and mailing has increased, while communication means requiring confidentiality such as personal information and direct mail applications with high quality printing have been applied. Is given importance and demanded.

Further, with the revision of the Postal Law, postcard systems having confidentiality have been put to practical use and have become widespread. A postcard system with confidentiality is to fold a reciprocating postcard with various information such as personal information folded and written on the inside,
The superimposed portion is pseudo-adhered to conceal the information, then mailed, and the recipient peels off the pseudo-adhered portion to read the concealed information. Among these communication means requiring confidentiality, for example, there is a method in which a company notifies employees and a bank or credit company communicates information having confidentiality to customers.

As a communication means having such a confidentiality, a method using a pseudo-adhesive sheet has been proposed and widely used. The pseudo-adhesive sheet is a so-called pseudo-adhesion mainly composed of a so-called pressure-sensitive adhesive such as a natural rubber and a synthetic rubber and a particulate filler for suppressing the adhesive force of the adhesive on at least a part of one side of the base material. Agent layer is provided,
It has a function of temporarily bonding but easily peeling off when necessary.

[0005] On the other hand, in the direct mail use notification means on which high-quality printing has been performed, when performing high-quality printing, the back side of the printing surface is folded in half in order to conceal print-through on paper. Pressure-sensitive adhesion to the fold surfaces that cannot be separated (including those that cannot be completely peeled, but that can be peeled but the adhesive layer breaks when the peeling or part or all of the base material breaks) A permanent adhesive sheet is formed by bonding with an agent.

[0006] The pseudo-adhesive sheet and the permanent adhesive sheet in this case are formed by forming a single layer of an adhesive on a substrate.

Incidentally, the pressure-sensitive adhesive deteriorates with time (hereinafter also referred to as aging phenomenon) as represented by yellowing, a decrease in adhesive strength, and curing. Natural rubber is particularly an aging phenomenon. The change in performance is remarkable. Generally, the aging phenomenon of a pressure-sensitive adhesive is mainly caused by contact with atmospheric oxygen or the like and oxidation by absorption of ultraviolet rays.

Therefore, conventionally, in a pseudo-adhesive sheet or a permanent adhesive sheet, an antioxidant and an ultraviolet absorption inhibitor have been added to the adhesive layer to prevent oxidation of the adhesive.

[0009]

However, these agents, such as antioxidants and ultraviolet absorption inhibitors, are expensive, but are mixed in the pressure-sensitive adhesive. In order to exert the effect, it is necessary to add a predetermined amount or more to the pressure-sensitive adhesive layer. As a result, there is a problem that the adhesiveness is reduced depending on the type of the drug.

On the other hand, in the case of the pseudo-adhesive sheet, a predetermined amount or more of a pigment or a fine particle filler is added to the pseudo-adhesive layer in order to improve the physical properties of the paint, to improve the printability, and to prevent blocking. However, the characteristics greatly depend on the particle diameter and the amount of addition. The same is true for permanent adhesive sheets to which pigments or particulate fillers are added to prevent print strikethrough.

It is considered that these are caused by the addition of various functional agents (materials or agents) corresponding to the desired properties into a single adhesive layer.

[0012] Accordingly, a main object of the present invention is to provide an adhesive sheet that can be easily designed for obtaining required characteristics as the adhesive sheet.

[0013]

According to a first aspect of the present invention, there is provided a pressure-sensitive adhesive layer provided on a substrate, and a target sheet is peelable or non-peelable by the pressure-sensitive adhesive layer. An adhesive sheet for forming an adhesive structure to be adhered to, at least one surface of the substrate, a pressure-sensitive adhesive layer, having one or more functional layers in this order, the functional layer,
The suitability of the pressure-sensitive adhesive layer for the application of the adhesive sheet and the
In addition to enhancing at least one of the functions of the pressure-sensitive adhesive layer , the functional layer itself is a target sheet.
An adhesive sheet having no adhesiveness to a sheet.

[0014] In the present invention, the idea of adding various functional agents (materials or agents) to a pressure-sensitive adhesive in order to obtain required characteristics with only a single adhesive layer has been devised. In addition, one or more functional layers other than the pressure-sensitive adhesive layer are provided outside the pressure-sensitive adhesive layer, and the required function is exhibited in the functional layer, so that the function of the functional agent itself can be further exhibited.
By adding a functional agent to a single pressure-sensitive adhesive layer,
Deterioration of the properties of the pressure-sensitive adhesive itself can be prevented or suppressed.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the adhesive sheet according to the present invention will be described in more detail.

First, a preferred embodiment of the pseudo-adhesive sheet according to the present invention will be described with reference to the accompanying drawings.
The folding pseudo-adhesive feeding envelope shown in FIG. 1 is provided with a pressure-sensitive adhesive layer 2 on the surface of a base material 1 such as paper, and after printing the supply information on the pressure-sensitive adhesive layer 2, as shown in FIG. Then, the information printing surface 3 is folded in two on the inner surface from the center line in the printing surface printing direction, and is pressure-bonded. Address information 4 and the like are printed on the back surface.

In the tri-fold postcard shown in FIG. 2, pressure-sensitive adhesive layers 2 and 2 are formed on the front and back surfaces of a base material 1, and concealment information,
After the communication information and the address information 4 are printed, as shown in FIG. 8B, the address information printing surface is folded and pressure-bonded so that the address print surface becomes the front surface.

In the two-fold postcard shown in FIG. 3 and the partially folded postcard shown in FIG. 4, a pressure-sensitive adhesive layer 2 is formed on the inner side of the base material 1 in the folding, information is printed, and the information is folded and pressure-bonded. In each case, the pressure-sensitive adhesive layers 2 are overlapped with each other and pressure-bonded.

In the above example, the mailed recipient is obfuscated by looking at the pseudo-adhesive surface,
The print can be read.

On the other hand, a permanent adhesive sheet for use in direct mail or the like is printed on one side with high quality, and the back side of the printing surface is folded in two to conceal print-through on paper. Although they are bonded to each other with a pressure-sensitive adhesive so that they cannot be separated, their structures are not shown.

The adhesive sheet of the present invention is widely and suitably used for purposes other than those listed above. For example, the present invention is suitably used for various types of postcards, postcards, reports, tags, labels, price tags, and the like. By providing a non-coated portion, re-peeling can be facilitated.

In addition, there is also proposed an adhesive sheet using so-called coated paper such as art paper, coated paper, or lightweight coated paper as a base material, and having an adhesive layer provided on a coated surface. The base material does not prevent being a synthetic paper or a plastic film.

In the present invention, the base of the pressure-sensitive adhesive may be a latex, specifically a natural rubber-based, synthetic rubber-based or synthetic resin-based one used in conventional pressure-sensitive adhesives. Can be arbitrarily selected from, but in particular, natural rubber is sulfur-free vulcanized, natural rubber latex mixed with methyl methacrylate, obtained by graft copolymerization of methyl methacrylate on natural rubber Natural rubber latex, acryl-modified rubber latex, and a mixture of rubber latex and a protective colloid-based acrylic copolymer emulsion are suitable in terms of blocking resistance, aging resistance, ink adhesion, and the like.

As the fine particle filler for suppressing the adhesive force of the pressure-sensitive adhesive, all of the conventionally used fine particle fillers can be used. Specifically, calcite-based precipitated calcium carbonate forming primary or secondary aggregates, aragonite-based precipitated calcium carbonate forming primary or secondary aggregates, styrene beads, cereal starch, modified starch , Synthetic particulate silica, ordinary calcium, zinc, magnesium, oxides, hydroxides, carbonates or silicates of metals such as aluminum or titanium,
Or a mixture thereof. White carbon composed of a porous secondary aggregate can also be used.

As a method for applying the adhesive, an air knife coater, a blade coater, a curtain coater, a bar coater, a flexographic printing, a screen printing and the like are preferably used.

In the present invention, as shown in FIG. 5, a base material 10 is provided with a pressure-sensitive adhesive layer 11, and one or more functional layers 12 are provided. As shown in FIG. 6, two functional layers may be provided as the functional layers 12A and 12B, or three or more functional layers may be provided. The functional layer 12 or 12A, 12B is used for the application of the pseudo adhesive sheet as compared with the case where only the pressure-sensitive adhesive layer 11 is not provided.
Along with enhancing the function of at least one of the compatibility of the pressure-sensitive adhesive layer and the pseudo-adhesiveness of the pressure-sensitive adhesive layer ,
The functional layer itself has no adhesiveness to the target sheet
Things .

The functional layer is a layer formed with one or more functional agents for exerting the above functions.

Many examples of this functional agent can be given. For example, antioxidants, UV absorption prevention
Agents, lubricants , pigments, anti-slip agents, particulate fillers, buffers, antistatic agents, surfactants, thickeners, defoamers, release agents, antiblocking agents, printer toner fixing agents, and the like.

Conventionally, the behavior or function of the additives exemplified as the functional agent with respect to the adhesive in the adhesive sheet is extremely unclear, and when a plurality of them are added, the behavior becomes unclear, and the design of the adhesive sheet becomes unclear. It was a big obstacle. In addition, it also causes dispersibility of the additive when applied on the substrate, changes over time of the coating solution, and changes in the formation behavior of the coating film after application.

Further, by adding additives to the adhesive, deterioration of the adhesive, yellowing with time, change in adhesive strength with time, deterioration of perforation and folding workability at the time of foam processing are caused, and This causes blocking, adhesion of an adhesive to a portion not desired to be bonded, and stickiness of the coating film surface, which is likely to occur particularly when a natural rubber-based pressure-sensitive adhesive or the like is used.

However, according to the present invention, by providing the functional layer, the functional agent in the functional layer can exhibit the suitability for the use of the adhesive sheet without adversely affecting the adhesive. Further, since the function layer can exhibit its function only with a thin film thickness, a smaller amount is required as compared with the case where an additive is added to the adhesive, and the cost can be reduced. The functional layer may improve adhesion.

Further, by providing a functional agent for blocking, which is a conventional problem, for example, a fine particle filler in the functional layer, a small amount of the fine particle filler can be obtained.

If necessary, a fine particle filler having a particle size that does not adversely affect the functional layer and has a particle size of, for example, less than 1 μm can be added to the pressure-sensitive adhesive layer. Thereby, the stability of the solid content of the pressure-sensitive adhesive paint, the controllability of the viscosity and the PH, and the like are improved.

When the application of the pressure-sensitive adhesive layer is completed or the application of the functional layer is completed, the surface is weighed about 1 to 10 kg.
It is preferable to apply a pressure of / cm ² to flatten excessive protrusions on the surface, preferably to adjust the surface roughness to 30 to 5 μm.

On the other hand, adhesive sheets are currently widely used for postcard applications. Taking the use for postcards as an example, the printing of concealment information on postcards employs various printing methods such as ink jet printing in addition to electronic copying. Taking the electronic copying method and ink jet printing as examples, the appropriate quality required for the adhesive sheet differs depending on the printing method. For example, in the electronic copying method, the electric resistance of the surface, ink jet printing, etc. Then there is ink absorption on the surface.

In this case, the functional layer according to the present invention comprises an electric conductive layer and a printer toner fixing layer for electronic copying printing, an ink absorbing layer mixed with fine particles and a binder for ink jet printing, and a measure against ultraviolet rays. Can be formed as an ultraviolet absorbent layer, a water-resistant layer or the like in delivery slips.

In the case where a functional layer is provided, it is usually necessary to increase the bonding ability of the pressure-sensitive adhesive layer. Power can be fully obtained. The adhesive force can be adjusted by selecting the type of the base of the pressure-sensitive adhesive, the type of the fine particle filler, the type of the additive, or the blending ratio of these, depending on the application. When pressed with a sealer, the peel strength in a 25 mm width is preferably 25 g or more.

The thickness of each layer of each functional layer is desirably 2 μm or less. When several layers are provided, the total thickness is desirably 5 μm or less. It is necessary to increase the surface roughness of the material or to provide a pressure-sensitive adhesive layer having a stronger adhesive force.

(Examples) Tables 1 and 2 show a comparison between a case where various functional agents are internally added and a case where various functional agents are shared as a functional layer. Table 3 shows the evaluation criteria.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

From these results, it is understood that the intended characteristics can be easily obtained by providing the functional layer according to the present invention.

[0044]

As described above, according to the present invention, it is possible to provide an adhesive sheet that can be easily designed for obtaining required characteristics as an adhesive sheet.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a folding pseudo-adhesion feeding envelope.

FIG. 2 is an explanatory diagram of a tri-fold postcard.

FIG. 3 is an explanatory diagram of a two-fold postcard.

FIG. 4 is an explanatory diagram of a partially folded postcard.

FIG. 5 is a sectional view of a pseudo-adhesive sheet provided with a functional layer.

FIG. 6 is a cross-sectional view of a pseudo adhesive sheet provided with two functional layers.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base material, 2 ... Pressure sensitive adhesive layer, 3 ... Information printing surface, 4 ... Address information, 10 ... Base material, 11 ... Pressure sensitive adhesive layer, 12 ... Functional layer.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-18232 (JP, A) JP-A-3-20179 (JP, U) Tokushou 62-500306 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) C09J 7/02 B42D 15/02

Claims (1)

(57) [Claims] An adhesive sheet for forming an adhesive structure in which a pressure-sensitive adhesive layer is provided on a base material, and a target sheet is peelably or non-peelably bonded by said pressure-sensitive adhesive layer, At least one surface of the substrate has a pressure-sensitive adhesive layer, one or more functional layers in this order, and the functional layer is used for the bonding sheet as compared with a case where only the pressure-sensitive adhesive layer is not provided. Pressure-sensitive adhesive layer for
And at least one of the function of the pressure-sensitive adhesive layer and the function of the functional layer.
An adhesive sheet having no adhesiveness to a target sheet itself .