JP2000085271A - Sealed information medium having re-peelability, and pressure-sensitive adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent re-peelability by sealing an information medium sheet for which a base material sheet for printing, a printing pattern, a pressure- sensitive adhesive composition layer, and a printing portion are laminated, in such a manner that the printing portion sides are bonded with each other, and preparing the pressure-sensitive adhesive composition with an adhesive major agent and a specified filler as the components. SOLUTION: This sealed information medium having re-peelability, which is suitably used for a postcard or the like, and can be unsealed, is constituted in such a manner that an information medium sheet wherein a base material sheet for printing, a printing pattern, a pressure-sensitive adhesive composition layer, and a printing portion are laminated in order, may be sealed by bonding the printing portion sides with each other. In this case, the pressure-sensitive adhesive composition is prepared using a substance having a property to be bonded by pressing, comprising at least an adhesive major agent and a filler as the components, the filler having an optical index of refraction of 1.60 or lower, being porous, and having a particle diameter of 2-20 μm. As such a filler, a particle of an organic polymer, a crosslinked acrylic resin, or a crosslinked styrene resin can be counted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing base sheet such as paper, which is coated with a releasable adhesive, printed, folded, and pressed with the printing base sheet side outside. Thus, the present invention relates to a sealed information medium that can prevent printed information from being exposed to the eyes of a third party and that can be opened when necessary without damaging the printed information. Such a sealed information medium can be applied to postcards, direct mails, various notifications, pamphlets, lottery and the like in which the number needs to be hidden. Further, the present invention relates to a pressure-sensitive adhesive composition which defines the properties of particles to be added and is suitable as a material constituting such a sealed information medium.

[0002]

2. Description of the Related Art Two types of information, a printed pattern consisting of common fixed information and individual variable information, are provided on a printing base sheet, and a layer of a removable adhesive composition is provided. There are roughly two types of sealed information media that are folded and bonded together with the side with the layer of the adhesive composition inside. One is a type in which a layer of a removable pressure-sensitive adhesive composition is provided on a printing base sheet, fixed information is subsequently printed, variable information is printed after printing, and finally folding and bonding are performed. Since the pressure-sensitive adhesive composition is applied prior to printing, it is called a “pre-paste method”. The other is
This is a type in which fixed information is first printed on a printing base sheet, a layer of a releasable pressure-sensitive adhesive composition is provided after printing, variable information is printed thereafter, and finally folded and attached. The application of the pressure-sensitive adhesive composition after printing is referred to as a “post-paste (paste) method”.

[0003] In the "glue method", there may be some problems. For example, (1) Usually, after printing, printing is carried to another place after a while, so that it is easy to block during handling and storage during that time. (2) There is a problem in printing, for example, generation of slag. (3) The printing of the fixed information may lower the adhesiveness. (4) After pressure bonding, it may not be peeled off smoothly from a predetermined interface. And so on. Also, in the “post-paste method”, points other than (3) in the above “pre-paste method” were common.
Because a layer of the adhesive composition that can be peeled off after printing is provided,
(5) There is a problem that print visibility is impaired.

[0004] The reason why the "post-glue method" impairs the visibility of printing is that, with a sealed information medium as in the present invention, it is troublesome to have adhesiveness before sticking or after sticking and peeling. In order to prevent the blocking of (1) in the “paste method”, usually starches having a particle size of 10 to 20 μm are added. This is because particulate silica having a particle size of 3 to 10 μm is added in order to eliminate the generation of scum and the point (4) in which the particles are not peeled off smoothly. When these particles are used, the purpose of the addition is achieved, but in particular, the latter silica has a content of 0.1%.
Fine particles of about 1 μm are secondarily aggregated to form large secondary particles, and the secondary particles have a porous surface shape, become white and opaque, and impair print visibility. If fine silica particles that do not undergo secondary agglomeration are used for the purpose of improving this point, the transparency will increase or other points will recede, making it difficult to achieve compatibility.

[0005]

In the present invention, problems which have been difficult to solve in the past, such as obstruction at the time of printing, for example, generation of scum are prevented. It is an object of the present invention to solve the problem and to realize high transparency and not to impair the visibility of the base.

[0006]

According to the study of the inventor,
As the condition of the particles, the refractive index of the light of the particles is 1.60 or less, and even if secondary particles are formed, the particles are not porous, that is,
Those that are non-porous and have an average particle size of 2 to 20 μm have been found to be optimal.

Specifically, the invention according to claim 1 is an information medium sheet in which a printing base sheet, a printed pattern, a layer of a pressure-sensitive adhesive composition, and a printed portion are sequentially laminated. The pressure-sensitive adhesive composition is adhered and sealed so that certain sides are in contact with each other, and the pressure-sensitive adhesive composition does not adhere in a normal state, but has a property of adhering under pressure, and is filled with at least the adhesive main agent. And a filler, wherein the filler has an optical refractive index of 1.60 or less, is non-porous, and has a particle size of 2 to 20 μm.
The present invention relates to a releasable sealed information medium.

A second aspect of the present invention relates to the removable information medium of the first aspect, wherein the filler is organic polymer particles. A third aspect of the present invention relates to the removable information medium according to the second aspect, wherein the filler is a crosslinked acrylic resin or a crosslinked styrene resin.

The invention of claim 4 is characterized in that it does not adhere in a normal state, but has the property of adhering under pressure, and comprises at least a pressure-sensitive adhesive main component and a filler, and the filler has an optical refractive index. 1.60 or less, non-porous,
The present invention also relates to a pressure-sensitive adhesive composition having a particle size of 2 to 20 μm.

A fifth aspect of the present invention relates to a pressure-sensitive adhesive composition according to the fourth aspect, wherein the filler is organic polymer particles. The invention of claim 6 relates to the pressure-sensitive adhesive composition according to claim 5, wherein the filler is a crosslinked acrylic resin or a crosslinked styrene resin.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As printing base sheets, papers such as high quality paper, recycled paper, paper such as copy paper, recording paper such as pressure-sensitive copy paper, and thermal recording paper are suitable. Further, those having a plastic film on the surface, such as foamed polyethylene terephthalate resin film other than paper, polyethylene-laminated paper, polypropylene film, etc., are also suitable.

The printing pattern is provided by editing characters, lines, photographs, pictures, etc., creating a printing plate, and printing. Although it is planned as appropriate each time, it is usually used as a column for entry such as sentences for explanation, pictures, photographs, etc., color dots for adjusting the ground color of the whole or part, and mail. If there is, the display of postcards and the like, the stamp pasting column, the postal code entry column, the sender's address, the corporate name, the representative name, etc. are printed. As a printing method for providing a print pattern, offset printing is generally used, but an electrophotographic method or the like can also be applied.

The layer of the pressure-sensitive adhesive composition is a characteristic part of the present invention. The performance required of this pressure-sensitive adhesive composition is as follows: (1) When applied to an object, it does not adhere even if the applied surfaces are combined by ordinary handling, but adheres when a strong pressure is applied ( 2) The adhered material can be smoothly re-peeled with a relatively weak force. (3) It must be transparent. (4) When printing on it, no residue is formed on the printer.

In order to satisfy such demands, the pressure-sensitive adhesive composition comprises a main component of an adhesive and a specific filler as main components. The main adhesive itself may be a known adhesive, and may be various kinds of pressure-sensitive adhesives such as rubbers. For example, acrylic modified natural rubber (PMMA-NR), which is obtained by graft-polymerizing methyl methacrylate onto natural rubber (NR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), polyacrylate, and the like can be recommended. Natural rubber (NR) or modified natural rubber (P) obtained by graft polymerization of methyl methacrylate onto natural rubber (NR)
MMA-NR) is easily gelled by an emulsifier,
A soap-free type without an emulsifier is desirable. As for those which do not gel by the addition of the emulsifier, that is, those which do not generate aggregates, those in the state of an emulsion are used. When isopropyl alcohol is added to the emulsion, it functions not only as an antifoaming agent, but also as a diluting solvent, and its transparency is increased.

It is particularly preferable to use a filler having an optical refractive index of 1.60 or less, a non-porous material and a particle size of 2 to 20 μm as a filler to be added to the above-mentioned pressure-sensitive adhesive base material. .

If the optical refractive index of the filler is equal to the optical refractive index of the polymer surrounding the filler, it can be theoretically transparent even if the filler is added. However, although it may depend on the other limiting conditions of the filler, there is no practical problem even if the optical refractive index is 1.59 in the range tested, and the optical refractive index of the pressure-sensitive adhesive base material is not affected. On the other hand, it is +0.2, and by analogy with this, it seems that there is no problem up to the range of -0.2, and that the range of ± 0.2 can be used.

When the shape of the filler is such as to form the secondary particles as described above, it is generally porous when the secondary particles are taken as one particle.
It does not necessarily form spherical particles and does not necessarily have to be spherical,
It is desirable that the shape has little unevenness. In this regard, the particles of the organic polymer have a shape close to a sphere and are preferable. Among them, an acrylic resin such as cross-linked polymethyl methacrylate particles or a cross-linked polystyrene resin is particularly preferable because of its excellent transparency and chemical normality.

The range of the particle diameter of the filler from 2 μm to 20 μm is an empirical value from an experiment in which the particle diameter is changed.
There is an effect between μm and between them, and at 0.9 μm below the lower limit, the adhesiveness does not change even if added, it remains tacky even when touched with the fingers of the hand, and there was a problem in handling,
Even when the addition was 25 μm or more, the adhesion was not sufficiently performed even if pressure was applied. Table 1 shows the transparency, pressure-sensitive adhesiveness, dry tack, anti-blocking properties,
The evaluation results for each check item of the removability are summarized in Table 3 below. Further, "Table 2" collectively shows maker names and product names of the pressure-sensitive adhesive main agent and the filler used in "Table 1".

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

It is preferable that the pressure-sensitive adhesive main agent and the filler are in a weight ratio of pressure-sensitive adhesive main agent / filler = 100/10 to 100/100. In order to apply the pressure-sensitive adhesive composition obtained by kneading with this composition to the sealed information medium of the present invention, it is diluted so as to have an appropriate viscosity, and a coating means such as a roll coater, a gravure roll coating, and a silk screen printing machine is used. Perform using.

As described above, it is usual and economical to print after providing a layer of the pressure-sensitive adhesive composition. This is because the processes up to providing the layer of the pressure-sensitive adhesive composition, printing, sealing, and subsequent processing are performed in different industries. However, it is possible to provide a layer of the pressure-sensitive adhesive composition after providing the printing portion, provided that the equipment conditions are in place, and there is no problem. The above-mentioned pressure-sensitive adhesive composition is, of course, suitable for the sealed information medium of the present invention, but one of the base materials is a heat-sensitive paper. Also suitable for applications such as slips.

Although the printing base sheet, the printed pattern, and the layer of the pressure-sensitive adhesive composition are laminated in this order, the printed portion is formed on the layer of the pressure-sensitive adhesive composition by using a non-impact printer or the like. Provide. The printing unit prints data selected under certain conditions using output data from a computer. In printing, sheets to be supplied may be continuous or one by one. In addition, the printing portion is usually formed of characters or ruled lines of one color, but may include multicolor printing, printing using an electrophotograph, and printing of an image using an electrophotography. "And" printing unit "include printing of an image.

After the printing portion is provided, a predetermined folding process is performed, the printing portion is folded with the layer of the pressure-sensitive adhesive composition on the inside facing inward, and sealed by applying a predetermined pressure. It shall be a sealed information medium.

[0026]

According to the first aspect of the present invention, there is a pressure-sensitive adhesive property for bonding at a predetermined pressure, and the transparency is high, so that the printed pattern of the base can be visually recognized sufficiently, the dry tack property is obtained, and the printability is improved. It can be prevented from sticking carelessly during storage and handling of the product. In addition, the peel strength at the time of opening is also appropriate, it is not peeled off by accident during handling, and when a person who is qualified to open is opened, it is difficult to peel off and it is not painful, A releasable sealed information medium can be provided.

According to the second aspect of the present invention, transparency is high,
Since the particle size is well controlled, the adhesiveness is stable. According to the third aspect of the present invention, since the filler is chemically stable and hardly crushed by pressure, the pressure-sensitive adhesive property and the removability are hardly impaired.

According to the fourth aspect of the present invention, despite the fact that a sufficient adhesive performance can be exerted by a predetermined pressure, the object is coated and wound or overlapped, so that the pressure is applied. Thus, it is possible to provide an extremely easy-to-use pressure-sensitive adhesive composition which is difficult to block and can be stably peeled off with a relatively light force after being once adhered.

According to the fifth aspect of the present invention, since the transparency of the composition is high and the particle size is well controlled, the properties of the pressure-sensitive adhesive composition are stabilized. According to the invention of claim 6, further,
Since the filler is chemically stable and does not easily collapse even by pressure, the pressure-sensitive adhesive property and the removability are hardly impaired when the pressure-sensitive adhesive composition is applied to an object.

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Claims (6)

[Claims] 1. An information medium sheet in which a printing base sheet, a printed pattern, a layer of a pressure-sensitive adhesive composition, and a printed portion are laminated in this order, so that the sides having the printed portions are in contact with each other. The pressure-sensitive adhesive composition is not adhered in a normal state, but has the property of adhering under pressure, and has at least an adhesive main agent and a filler as components, and the filler Is a releasable sealed information medium characterized by having an optical refractive index of 1.60 or less, being non-porous, and having a particle size of 2 to 20 μm. 2. The removable information medium according to claim 1, wherein the filler is organic polymer particles. 3. The filler according to claim 2, wherein the filler is a crosslinked acrylic resin or a crosslinked styrene resin.
A releasable sealed information medium as described in the above. 4. It does not adhere in a normal state, but has the property of adhering under pressure. It comprises at least a pressure-sensitive adhesive main agent and a filler, and the filler has an optical refractive index of 1.60 or less. Yes, non-porous, and particle size 2 ~
A pressure-sensitive adhesive composition having a thickness of 20 μm. 5. The pressure-sensitive adhesive composition according to claim 4, wherein the filler is organic polymer particles. 6. The filler according to claim 5, wherein the filler is a crosslinked acrylic resin or a crosslinked styrene resin.
The pressure-sensitive adhesive composition as described in the above.