JPH0718232A - Paper for pseudoadhesion and pseudoadhesive composition used therefor - Google Patents

Abstract

PURPOSE:To obtain the paper which does not stain the surface on which informations are printed when it is peeled after pseudoadhesion and does not decrease in its pseudoadhesion with the lapse of time. CONSTITUTION:The paper is prepared by forming a layer made of a pseudoadhesive composition comprising a pressure-sensitive adhesive comprising a latex, a fine particulate filler composed of at least two fillers and having no affinity for the pressure-sensitive adhesive and a modified PVA having an affinity for both the pressure-sensitive adhesive and the fine particulate filler on part of at least either surface of a supporting sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention provides temporary bonding,
The present invention relates to a pseudo-adhesive paper having a function of easily peeling off when necessary and a pseudo-adhesive composition used for the pseudo-adhesive paper. More specifically, an adhesive that does not normally adhere and is pseudo-adhesively peeled off when given conditions are given,
Pseudo-adhesive paper suitable for folding pseudo-adhesive paper, overlapping pseudo-adhesive paper, and other information-concealing paper having confidentiality, confidential postcards, envelopes, etc., applied to at least a part of one side of the support, and The present invention relates to a pseudo adhesive composition used.

[0002]

2. Description of the Related Art In recent years, while the amount of information transmitted by communication means such as communication and mail has increased, communication means requiring personality such as personal information have been emphasized and demanded.

Also, with the revision of the Postal Law, a postcard system having confidentiality has been put into practical use and has begun to spread. This confidential postcard system folds a reciprocal postcard in which various information such as personal information is folded and folds and pseudo-bonds the overlapped parts to hide the information, then mail and receive it. This is a system in which a person peels off a pseudo adhesive portion to read hidden information. For example, when a company contacts employees with confidential information to a customer, such as a bank or a credit company, confidential information is prevented from leaking, convenience of information communication, Ease of opening is a major issue.

Conventionally, a thermoplastic resin layer is provided on a support,
After printing the confidentiality information, the resin layers are made to face each other to be heat-bonded, or the heat-sensitive or pressure-sensitive non-peeling adhesive is used to obtain the confidentiality. These types of heat-bonding, heat- or pressure-sensitive non-peeling adhesive methods are capable of large-scale processing using computers and printing machines, and are in increasing demand.

[0005]

However, although the heat-bonding and the bonding with the pressure-sensitive or pressure-sensitive non-peeling adhesive have the above-mentioned convenience, perforation processing is required in order to avoid damage to necessary parts when opening. In addition, there are problems that a piece is generated when opening, and it cannot be used in the postcard system. The second means to solve these problems
An information laminated body that can be mailed as a standard type mail has been proposed, and an example thereof is disclosed in JP-A-4-59395. This is to provide an adhesive layer composed of a non-peeling adhesive that is conventionally used and a fine particle filler that has no affinity for the adhesive base on at least a part of the base sheet surface. It is a thing.

The conventional general method is represented by the prior art described in the above-mentioned publication, and it is common in that a non-peeling adhesive agent and a fine particle filler having a non-affinity for it are combined. There is. However, the combination of the non-peeling adhesive and the non-affinity fine-grained filler is not only insufficient in printing with an electrophotographic system or an impact / non-impact printer, but also when peeled again after pseudo-adhesion. There are problems that the printing is transferred to the opposite surface and the information printing surface is soiled, and that pseudo adhesive strength deterioration occurs over time, peeling occurs, and adhesive sag occurs.

Therefore, an object of the present invention is to provide a pseudo-adhesive paper which is free from stains on the information printed surface when it is peeled off again after pseudo-adhesion and deterioration of pseudo-adhesive strength over time, and a pseudo-adhesive composition used therefor. It is in.

[0008]

On the other hand, the present inventor
As a result of earnest research and development, a pressure-sensitive adhesive made of latex and at least a part of at least two kinds of fine particles having incompatibility with the pressure-sensitive adhesive are filled on at least a part of one side of the support sheet. It was found that the above-mentioned problems can be achieved by providing a layer of a pseudo-adhesive composition composed of an agent and a modified PVA having an affinity for both the pressure-sensitive adhesive and the fine particle filler, The invention was completed.

The pseudo-adhesive composition of the present invention comprises a natural rubber latex obtained by graft-polymerizing methyl methacryl on natural rubber, silica having an average particle diameter of 1 to 15 μm, and 5 to 5
It is characterized by comprising modified PVA, which is composed of grain particles of 15 μm, and which contains the fine particle filler, in which the secondary average particle diameter X of silica and the grain particle diameter Y satisfy the relational expression X ≦ Y.

A pressure-sensitive adhesive 80 made of latex
~ 95 parts by weight of finely divided filler 2 made of silica
0-50 parts by weight, 50-particulate filler composed of grain particles
An embodiment in which 150 parts by weight and 5 to 20 parts by weight of silicon-modified PVA are mixed is also included.

The pseudo-adhesive paper of the present invention can be applied to folding pseudo-adhesive paper, superposed pseudo-adhesive paper, information-concealing paper having confidentiality, confidential postcards, confidential envelopes, and the like.

The following are examples of these pseudo-adhesive papers. That is, in the folding pseudo-adhesive feeding envelope shown in FIG. 1, the pseudo-adhesive layer 2 is provided on the surface of the support sheet 1, and the pay-feed information is printed on the pseudo-adhesive layer 2 and then shown in FIG. In this way, the information printing surface 3 is valley-folded from the center line in the printing surface printing direction to the inner surface and pressure-bonded. Address information 4 and the like are printed on the back surface.

In the tri-fold postcard shown in FIG. 2, pseudo adhesive layers 2 and 2 are formed on the front and back surfaces of a support sheet 1, and concealment information 3, communication information, and address information 4 are printed on the surface thereof,
As shown in FIG. 6B, the address printing surface is folded and pressure-bonded so that the surface is the front surface.

In the double-folded postcard shown in FIG. 3 and the partially-folded type postcard shown in FIG. 4, a pseudo adhesive layer is formed on the inner surface of the support sheet 1 in the folded state, information is printed, and the sheets are folded and pressure-bonded. In either case, the pseudo adhesive layers are superposed on each other and pressure-bonded.

In addition to the uses listed in these examples, it is widely and suitably used for various postcards, envelopes, and reports, such as applying a pseudo adhesive to only a part of the support sheet,
It is also possible to facilitate re-peeling by providing a non-coated portion.

The pressure-sensitive adhesive made of latex used in the pseudo-adhesive paper of the present invention has the property of not adhering in a normal state but adhering under pressure, such as natural rubber and synthetic rubber. It can be arbitrarily selected from those used for ordinary pressure-sensitive adhesives such as, but especially natural rubber latex obtained by graft-copolymerizing methyl methacrylate to natural rubber, It is preferable in terms of blocking property, deterioration with time, ink inking property, and the like.

The fine particle filler having a non-affinity for the pressure-sensitive adhesive in the present invention has a small affinity with the pressure-sensitive adhesive, such as calcium carbonate, kaolin, talc, silica, urea resin, Styrene beads, calcined clay, grain starch, silica gel, modified starch and the like can be preferably used, and it is necessary to use at least two kinds of them in combination.

When using two or more kinds of fine particle fillers having different particle diameters and specific surface areas, the reason for making the particle diameters different is to make the surface of the pseudo adhesive uneven so that the pseudo adhesive force and the peeling force can be adjusted. To make it easier. In addition, the reason why the specific surface area is different is that the adhesive ability of the pressure-sensitive adhesive to the surface of the non-affinity fine particle filler is different, so that the pseudo adhesive force can be adjusted in a fine region, and the adhesive force and the peeling force can be adjusted. This is because it is adjustable.

A combination of silica and grain starch is particularly preferred. Since silica is porous, it is easy to attach the pressure-sensitive adhesive to the surface, and since the pressure-sensitive adhesive is easily held on the support surface, it is easy to adjust the pseudo adhesive force. The amount can be controlled to a minimum. 2 for silica
Those having a secondary particle size in the range of 1 to 15 μm, particularly 3 to 15 μm can be preferably used. Since grain starch does not have a porous surface, the adhesion of pressure-sensitive adhesive is small, and the secondary particle size is equal to or larger than that of silica, and the particles themselves have elasticity. The effect is exhibited, the adjustment of the pseudo adhesive force is facilitated, and the adhesion of the pressure-sensitive adhesive is small, so that blocking can be prevented and a paper-like feel can be obtained. The grain size of grain starch is 1 ~ 30μm,
It is preferably 5 to 20 μm. The secondary average particle diameter (X) of silica and the grain particle diameter (Y) are X
It is preferable to satisfy the relational expression ≦ Y.

Further, as the modified PVA having an affinity for both the pressure-sensitive adhesive and the fine particle filler in the present invention, a carboxy group-modified PVA and a sulfone group-modified PV are used.
A, acetoacetyl group-modified PVA, cationic group (quaternary ammonium salt) -modified PVA, and silicon group-modified PVA can be used, but silicon group-modified PVA is particularly preferable.

Since the silicon group-modified PVA has a remarkable interaction with various inorganic substances and particularly forms a chemical bond with silica, it has a film forming property with the fine particle filler when the pseudo adhesive layer is formed. Excellent, because the film is transparent, tough, and has excellent barrier properties, it has a high affinity with pressure-sensitive adhesives, prevents the pressure-sensitive adhesives from deteriorating over time, improves printability, and transfers printing to the opposite surface. The problem of the information printing surface becoming dirty is eliminated.

In the pseudo adhesive composition, 10 to 60 parts by weight, more preferably 20 to 50 parts by weight, of a fine particle filler made of silica, and 80 to 95 parts by weight of a pressure sensitive adhesive made of latex, and grain particles are used. Fine particle filler consisting of 4
It is desirable to add 0 to 250 parts by weight, more preferably 50 to 150 parts by weight, and 2 to 30 parts by weight of silicon-modified PVA, and more preferably 5 to 20 parts by weight. If the blending amount of the fine particle filler is less than the above range, a problem of blocking occurs and re-peeling becomes difficult. In particular, when the amount of the grain starch is small, the problem becomes remarkable. When it exceeds the above range, the pseudo-adhesive strength becomes poor and peeling easily occurs. If the amount of the silicon-modified PVA compounded is less than the above range, the surface strength will be poor, silica powder will fall off, the printing machine and pressure machine will be contaminated, and the pseudo adhesive layer will peel off. When it exceeds the above range, the pseudo adhesive strength is deteriorated due to the barrier property, which is not preferable.

In the pseudo-adhesive composition used in the pseudo-adhesive paper of the present invention, it is necessary to appropriately select the compounding ratio of the pressure-sensitive adhesive, the fine particle filler and the modified PVA used in this way.

The pseudo-adhesive paper of the present invention can be obtained by providing a layer of the pseudo-adhesive composition on at least a part of one side of a support sheet. The pseudo-adhesive layer is printed with a uniform pseudo-adhesive surface. In order to obtain aptitude, apply coating with a vent blade, comma, lip or air knife, pressurize the pseudo adhesive surface at about 1-10 kg / cm ² , and flatten the excessive protrusion of the pseudo adhesive surface. Is preferred.

[0025]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples. The adhesive strength, blocking resistance, printability, stains on the information printed surface, deterioration of the pseudo adhesion with time, and surface strength were determined as follows. (1) Adhesive strength After the test sample was aged for 24 hours in an environment of 20 ° C. and 65 RH, the pressure of the dry sealer was 50 kg / c.
The adhesive strength was adjusted to m ² and pseudo-adhesion was performed, and the peel strength of a 25 mmφ sample was measured at a head speed of 300 mm / min.

(2) Blocking resistance According to the method shown in JIS-K 6833, 38 ° C,
The blocking property after standing for 24 hours at 91% RH was evaluated.

(3) Printability The impact printer (Toshiba dual-mode printer) prints special characters up to JIS character codes 2122 to 2576, numbers, Roman letters, hiragana, and katakana, and the print is blurred and the printer is dirty. Was measured comparatively.

(4) Dirt on information printed surface An impact printer (Toshiba dual mode printer) printed special characters up to JIS character codes 2122 to 2576, numbers, Roman characters, hiragana and katakana, and made 20 test samples. After curing at 65 ℃ for 24 hours, dry sealer pressure is set to 50k.
It was adjusted to g / cm ² and pseudo-adhesive under pressure, and the degree of print transfer to the opposite surface was evaluated.

(5) Deterioration of pseudo adhesive strength over time Weather meter (WEL-45AX manufactured by Suga Test Instruments Co., Ltd.)
Then, the peel strength was measured after standing for 40 hours with a xenon lamp at 63 ° C. and 40%. To measure the peel strength, a tensile tester STROG RAPH-R type manufactured by Toyo Seiki Co., Ltd. was used. In addition, the results of the evaluation of each physical property were performed by the following ranking.

⊚: excellent, ◯: good, Δ: acceptable, ×: not acceptable (Example 1) 90 parts by weight of methyl methacrylate graft copolymerized natural rubber latex (solid content%, FB-DO-3 manufactured by Mitsui Fuller Co.) On the other hand, silica 30 having an average particle size of 3 μm
Parts by weight, flour starch 70 parts by weight and silicon-based modified PVA
(Kuraray R1130) 10 parts by weight was added to obtain a pseudo adhesive composition. Next, the adhesive composition using a multi-coater, was coated so as the coating amount is 8 g / m ² (solid content basis) to create a test sample to form a sheet of 127 g / m ^2, Each physical property was calculated. The results are shown in Table 1.

Example 2 The amount of silica in Example 1 was 50 parts by weight, wheat starch was 50 parts by weight, and modified PVA.
Was carried out in the same manner as in Example 1 except that carboxy group-modified PVA was used instead of. The results are shown in Table 1.

Example 3 The amount of silica in Example 1 was 20 parts by weight, wheat starch was 100 parts by weight, and modified PV.
The same procedure as in Example 1 was carried out except that A was changed to a sulfo group-modified PVA. The results are shown in Table 1.

Example 4 Example 4 was carried out in the same manner as in Example 1 except that 200 parts by weight of wheat flour starch and 20 parts by weight of modified PVA were used. The results are shown in Table 1.
Shown in.

Example 5 Example 5 was carried out in the same manner as in Example 1 except that the amount of silica was changed to 40 parts by weight and the modified PVA was changed to 10 parts by weight. The results are shown in Table 1.

Example 6 The procedure of Example 1 was repeated, except that the natural rubber latex in Example 1 was changed to 80 parts by weight, the amount of silica was changed to 20 parts by weight, and the amount of wheat starch was changed to 50 parts by weight. .

The results are shown in Table 1.

(Comparative Example 1) The amount of silica in the example is 6
The same procedure as in Example 1 was carried out except that 0 part by weight was changed to 200 parts by weight of wheat starch. The results are shown in Table 1.

(Comparative Example 2) The procedure of Example 1 was repeated, except that 170 parts by weight of the wheat starch in Example 1 was replaced with 30 parts by weight of the modified PVA. The results are shown in Table 1.
Shown in.

COMPARATIVE EXAMPLE 3 Except that the amount of silica in Example 1 was changed to 10 parts by weight and the amount of modified PVA was changed to 2 parts by weight.
It carried out like Example 1. The results are shown in Table 1.

Comparative Example 4 The procedure of Example 1 was repeated except that the amount of wheat starch in Example 1 was changed to 20 parts by weight. The results are shown in Table 1.

(Comparative Example 5) The procedure of Example 1 was repeated, except that the natural rubber latex in Example 1 was changed to 150 parts by weight. The results are shown in Table 1.

[0042]

[Table 1]

[0043]

As described above, according to the present invention, by providing a pseudo adhesive layer of the pseudo adhesive composition according to the present invention on at least a part of one side of the support sheet, an appropriate pseudo adhesive strength can be obtained. While retaining, anti-blocking property, printability, prevention of stains on information printed surface, prevention of deterioration of pseudo adhesive strength over time, improved surface strength, which is a conventional problem, is extremely convenient. A pseudo adhesive paper that can be supplied at high cost and at low cost is provided.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a folded pay 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.

[Explanation of symbols]

1 ... Support sheet, 2 ... Pseudo adhesive layer, 3 ... Information printed surface, 4 ... Address information.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location B42D 15/02 501 BC09J 129/04 JCT JCU (72) Inventor Akira Takeda 5 Kamiyacho, Iyo Mishima City, Ehime Prefecture No. 1 Daio Paper Co., Ltd.

Claims (3)

[Claims] 1. A support sheet, on at least a part of one side thereof,
A pressure-sensitive adhesive composed of latex, a fine particle filler composed of at least two kinds having a non-affinity for the pressure-sensitive adhesive, and an affinity for both the pressure-sensitive adhesive and the fine particle filler. A pseudo-adhesive paper comprising a layer of a pseudo-adhesive composition composed of a modified PVA having properties. 2. A natural rubber latex obtained by graft-polymerizing methyl methacrylic on natural rubber, and an average particle size of 1 to 15.
The average particle diameter X of the silica and the particle diameter Y of the grain are X ≦
A pseudo-adhesive composition for pseudo-adhesive paper, comprising the fine particle filler satisfying the relational expression of Y and modified PVA. 3. A pressure-sensitive adhesive 80-95 made of latex.
Fine particles of silica 20 to 5 relative to parts by weight
Fine particle filler consisting of 0 parts by weight and grain particles 50 to 150
Pseudo-adhesive composition for pseudo-adhesive paper, wherein 5 parts by weight and 5 to 20 parts by weight of silicon-modified PVA are blended.