JPH044283A - Peelable adhesive composition - Google Patents

Abstract

PURPOSE:To obtain the title new composition suitably useful for confidential postcards such as foldable cards or information covering sheet by blending an unpeelable adhesive base with a finely granulated filler showing non-affinity for the base. CONSTITUTION:(A) 100 pts. wt. pressure-sensitive, heat-sensitive or rewet type unpeelable adhesive base comprising preferable natural rubber latex, a vinyl acetate-based polymer or PVA is blended with (B) a finely granulated filler such as zinc oxide, titanium oxide, calcium carbonate, kaolin, activated clay, spherical alumina, wheat starch, silica, glass powder or silas balloon (preferably blend of silica and another filler showing non-affinity for the component A in an amount of 100-400 pts. wt. in the case of the pressure-sensitive or rewet type unpeelable adhesive base or 45-100pts.wt. in the case of the heat-sensitive unpeelable adhesive base to give the objective composition.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel removable adhesive composition, and more particularly, to postcards, cards, etc. that have malleability such as folded cards, stacked cards, information hiding sheets, etc. A removable pressure-sensitive adhesive composition suitable for use in various systems,
The present invention relates to a heat sensitive adhesive composition or a rewetting adhesive composition.

BACKGROUND OF THE INVENTION In recent years, with the revision of the Postal Law, a secure No-Igaki system has been put into practical use and is beginning to become popular.

This secure postcard system folds a postcard containing various information such as personal matters or print information, glues the overlapping parts, and then mails the postcard to hide the information. This is a system in which the recipient peels off the overlapped portion again to read the hidden information.

A postcard system with such flexibility is generally applied to three-fold postcards, half-fold postcards, and partially folded postcards. Figures 1, 2, 3, and 4 show examples of the system applied to three-fold postcards, regular postcards, partially folded postcards, and stacked postcards, respectively. In the case of the three-fold postcard shown in FIG. 1, first fold the part where the adhesive layer 2 is provided on the back side along the dotted line 3, and fold the 4-fold postcard as shown in FIG. After superimposing the adhesive layer 1 on the surface thereof, the part on which the adhesive layer 1 is provided is folded along the dotted line part 3', and is superimposed on the adhesive layer l and bonded.
In the case of the normal postcard shown in the figure and the partially folded type postcard shown in Fig. 3, as shown in Figs. 6 and 7,
The part on which the adhesive layer 1 is provided on one side is folded along the dotted line 3', and the adhesive layer surfaces are overlapped and bonded. In addition, in the case of the type shown in Figure 4, there is an adhesive layer on the overlapping surface.
．． 2 is provided, and these surfaces are overlapped and bonded.

In such systems, after the sender enters information in the communication field, it must be hidden and the recipient must open the envelope again after receipt, so it is necessary to use removable adhesive. It is.

Up until now, the adhesive method with this function has been to provide an adhesive layer on one side of a laminate of two transparent films that can be peeled in the middle, and cover this adhesive layer with release paper for concealment. Affix it to the lid, fill in the necessary information in the communication field, remove the release paper, stack it on the communication field, and paste it. After the recipient receives it, peel it off between the two transparent films. However, methods for reading information are known. However, in this method, the cost of the adhesive film laminate is inevitably high, and the release paper must be removed before use, which is inconvenient.

On the other hand, to prevent blocking during storage and transportation,
Envelope forms coated with a pressure-sensitive adhesive that is a specific adhesive mixed with a non-thermoplastic microhard substance have also been proposed;
Once glued, the glued part cannot be peeled off, so it is necessary to glue some parts and make perforations in the other parts and cut them out. cannot be used for.

Problems to be Solved by the Invention The present invention overcomes the drawbacks of the adhesive layer in conventional flexible postcard systems such as concealing sheets, folded sheets, stacked sheets, etc., and eliminates blocking during inventory. The purpose of this invention is to provide a material that is inexpensive, has excellent adhesion and peeling performance, and is suitable for use in the adhesive layer.

Means to Solve the Problem As a result of various studies on removable adhesive compositions, the present inventor has discovered that they have no affinity for conventionally commonly used non-removable adhesive bases. We discovered that by blending a fine particulate filler and appropriately adjusting the amount of this particulate filler, an adhesive that can be easily bonded and easily peeled off when necessary was obtained, and based on this knowledge, we As a result, the present invention was completed.

That is, the present invention provides (A) a non-peelable adhesive base, (
B) To provide a removable adhesive composition comprising a particulate filler exhibiting non-compatibility with the adhesive base.
It is something.

The present invention will be explained in detail below.

There are three types of compositions of the present invention: pressure-sensitive adhesive compositions, heat-sensitive adhesive compositions, and rewetting adhesive compositions, and an appropriate adhesive base is used depending on each type. These are used as ordinary adhesives, and are originally of the type that do not peel off again once they have been bonded.

The pressure-sensitive adhesive composition of the present invention has the property of adhering under pressure without adhering in a normal state, and there are no particular restrictions on the adhesive base. Natural rubber latex, which is obtained by graft copolymerizing styrene and methyl methacrylate to natural rubber, can be selected arbitrarily from those commonly used as agents. It is suitable in terms of properties such as durability and abrasion resistance.

Further, the heat-sensitive adhesive composition of the present invention does not adhere under normal conditions, but has the property of adhering with heat or heat and pressure, and there are no particular limitations on the adhesive base. Any adhesive may be selected from those conventionally used in conventional heat-sensitive adhesives, and vinyl acetate polymers are particularly preferred.

Further, the rewetting adhesive composition of the present invention does not adhere under normal conditions but has the property of adhering upon rewetting, and the adhesive base is usually a water-soluble polymer compound or the like. It will be done. The water-soluble polymer compound is not particularly limited, and those conventionally used in rewetting adhesives, such as polyvinyl alcohol and polyethylene oxide, are preferably used.

In the composition of the present invention, the fine particulate fillers exhibiting incompatibility with component (B) include those having low affinity with the adhesive base of component (A), such as zinc oxide, titanium oxide, calcium carbonate, kaolin, Activated clay, spherical alumina, wheat starch, silica, glass powder, shirasu balloons, etc. are used. These materials may be used alone or in combination with
Although more than one type of filler may be used in combination, a combination of silica and other fillers is particularly preferred. Further, when two or more types of particles having different particle sizes are used in combination, the surface of the adhesive layer can be easily formed into an uneven shape, which is advantageous for improving the peeling performance. By adding silica, it is possible to strengthen the coating film of the adhesive, and since silica is porous, it easily adheres to the surface of the adhesive, making it easy to adjust the adhesion and peeling force, and making it easier to use silicone oil. Even when printing is performed using a non-impact printer method depending on the printer used, the silica absorbs the silicone oil, so the adhesive layer will not become unadhesive due to the silicone oil.

These fine particulate fillers have an average particle diameter of 10 mμm to
30 μm, preferably in the range of 1 to 20 μm.

The particulate filler can be used in any of pressure-sensitive adhesive compositions, heat-sensitive adhesive compositions, and rewet adhesive compositions, but in pressure-sensitive adhesive compositions and rewet adhesive compositions. 100 to 400 parts by weight, preferably 130 to 30 parts by weight of the fine particulate filler per 100 parts by weight of the adhesive component.
It is desirable that the amount is 0 parts by weight, more preferably 150 to 250 parts by weight. On the other hand, in the heat-sensitive adhesive composition, 45 to 100 parts by weight, preferably 55 to 90 parts by weight, more preferably 6 parts by weight, per 100 parts by weight of the adhesive component.
It is preferable to mix it in a proportion of 0 to 80 parts by weight. If the amount of the particulate filler is less than the above range, the blocking resistance will be poor and the adhesive force will be too strong, and if it exceeds the above range, the adhesive force will tend to be too low, which is not preferable.

In the adhesive composition of the present invention, it is necessary to appropriately select the blending ratio of the adhesive base and the particulate filler used in this way.

The releasable adhesive composition of the present invention can be applied to flexible postcards such as three-fold postcards, half-fold postcards, partially folded type postcards, and overlapping type postcards as shown in FIGS. 1 to 7 above. In addition to the system, lottery, learning materials,
Suitable for use as adhesive layer material in building materials such as wallpaper.

Effects of the invention By using the adhesive composition of the present invention in the adhesive layer of a postcard system that has compatibility when adhering various sheets, blocking does not occur during inventory, and it is also possible to use a non-impact printer method. Moreover,
Compared to pasting conventional adhesive films, manufacturing costs are significantly lower.

Examples Next, the present invention will be explained in more detail with reference to examples.
The present invention is not limited in any way by these examples.

Note that adhesive strength, blocking resistance, and heat and abrasion resistance were determined as follows.

(1) Adhesive strength l After heating the test sample at 180°C for 2 seconds,
After adjusting the pressure of the dry sealer to 50 to 9/crn'' and adhering under pressure, the peel strength was measured.

(2) Adhesive strength 2 After heating the test sample at 180°C for 2 seconds,
Silicone oil 0.59/+l with R1 tester
! Apply 2 coats and apply dry sealer pressure to 1100h/c.
After adjusting the pressure and bonding to m2, the peel strength was measured.

(3) Adhesive strength 3 The test samples were pasted together and heated at 180° using a heating device.
c. After heating for 2 seconds and allowing to cool, the peel strength was measured.

(4) Adhesive Strength 4 Water was applied to the test sample at 5 to 1h/m2, immediately bonded together, and after drying, the peel strength was measured.

(5) Blocking resistance test sample adhesive side together, 500 g/c
After applying a pressure of m2 and leaving it for 30 minutes at 50°C, the peel strength was measured.

(6) Heat resistance and abrasion resistance The adhesive surface was abraded with a metal at a temperature of 150° C. under a load of 200 to 500 g/cm2 (1), and the degree of wear was examined.

Note that a tensile tester Autograph AGS Model 50 manufactured by Shimadzu Corporation was used to measure the peel strength.

In addition, each physical property was evaluated according to the following symbols.

◎: Excellent, ○: Good, △: Fair, ×: Not Pressure-sensitive adhesive composition Example 1 2 parts by weight of styrene and 10 parts by weight of methyl methacrylate (MMA) were grafted onto 100 parts by weight of natural rubber. A base adhesive was prepared by adding 5 parts by weight of a terpene resin as a tackifier to the natural rubber latex obtained by polymerization. Next, 50 parts by weight of silica gel having an average particle size of 4 μm and 150 parts by weight of wheat starch having an average particle size of 15 μm were added to 100 parts by weight of this base adhesive to prepare a pressure-sensitive adhesive composition.

This adhesive composition was then applied using a wire bar for 7
Coating amount on 0kg high-quality paper is 5g/m2 (solid content equivalent)
After coating it so that The results are shown in Table 1.

Example 2 A test was carried out in the same manner as in Example 1 except that the amount of wheat starch in Example 1 was changed to 250 parts by weight.

The results are shown in Table 1.

Example 3 A test was conducted in the same manner as in Example 1, except that the amount of silica in Example 1 was changed to 100 parts by weight, and the amount of wheat starch was changed to 200 parts by weight. The results are shown in Table 1.

Example 4 The amount of styrene in Example 1 was changed to 8 parts by weight, and the amount of MMA was changed to 1 part by weight.
The same procedure as in Example 1 was carried out except that the amount was changed to 6 parts by weight. The results are shown in Table 1.

Example 5 The same procedure as in Example 4 was carried out except that the amount of wheat starch in Example 4 was changed to 250 parts by weight.

The results are shown in Table 1.

Example 6 The same procedure as in Example 4 was carried out except that the amount of silica in Example 4 was changed to 100 parts by weight and the amount of wheat starch was changed to 200 parts by weight. The results are shown in Table 1.

Comparative Example 1 A comparative example was carried out in the same manner as in Example 1, except that the amount of silica in Example 1 was changed to 30 parts by weight and the amount of wheat starch was changed to 60 parts by weight. The results are shown in Table 1.

Comparative Example 2 Comparative example 2 was carried out in the same manner as in Example 1 except that the amount of silica in Example 1 was changed to 60 parts by weight and the amount of wheat starch was changed to 30 parts by weight. The results are shown in Table 1.

Comparative Example 3 Comparative example 3 was carried out in the same manner as in Example 1 except that the amount of silica in Example 1 was changed to 200 parts by weight and the amount of wheat starch was changed to 250 parts by weight. The results are shown in Table 1.

Table 1 [Note] *1: Adhesive force is too strong and cannot be used *2: Filler falls off from the adhesive surface Heat-sensitive adhesive composition example 7 Vinyl acetate copolymer #3316 (manufactured by Nippon Fuller Co., Ltd.) ,
After preparing a heat-sensitive adhesive composition by adding 50 parts by weight of calcium carbonate having an average particle size of 2 μm to 100 parts by weight (trade name), test samples were prepared in the same manner as in Example 1, and adhesive strength 3 and Blocking resistance was determined. The results are shown in Table 2.

Example 8.9 In Example 7, instead of 50 parts by weight of calcium carbonate, 70 parts by weight of wheat starch with an average particle size of 15 μm (Example 8) and 90 parts by weight of titanium oxide with an average particle size of 1 μm (Example 9) It was carried out in the same manner as in Example 7 except that .

The results are shown in Table 2.

Example 1O In Example 7, 100 parts by weight of vinyl acetate copolymer The same procedure as in Example 7 was carried out except that 50 parts by weight of wheat starch having an average particle size of 15 μm was used instead. The results are shown in Table 2.

Examples 11', 12 In Example 10, 90 parts by weight of zinc oxide having an average particle size of 1 μm was used instead of 50 parts by weight of wheat starch (Example 11).
Example 10 was carried out in the same manner as in Example 10, except that 90 parts by weight of silica having an average particle size of 4 μm (Example 12) was used.

The results are shown in Table 2.

Comparative Example 4 Comparative example 4 was carried out in the same manner as in Example 7 except that the amount of calcium carbonate in Example 7 was changed to 20 parts by weight. The results are shown in Table 2.

Comparative Example 5 The same procedure as in Example 8 was carried out except that the amount of wheat starch was changed to 150 parts by weight. The results are shown in Table 2.

Comparative Example 6 The same procedure as in Example 1O was carried out except that the amount of wheat starch was changed to 15 parts by weight.

The results are shown in Table 2.

Comparative Example 7 In Example 12, the amount of silica was changed to 120! It was carried out in the same manner as in Example 12 except that the parts were changed.

The results are shown in Table 2.

Table 2 Example 13 Water-soluble polymer compound [manufactured by Hikari Kako Co., Ltd., trade name, KR
954) After preparing a rewetting adhesive composition by adding 150 parts by weight of silica having an average particle size of 4 μm to 100 parts by weight, a test sample was prepared in the same manner as in Example 1,
Adhesive strength 4 and blocking resistance were determined.

The results are shown in Table 3.

Example 14.15 In Example 13, 200 parts by weight of carbonic acid having an average particle size of 2 μm (Example 14) was used instead of 150 parts by weight of silica.
) and 250 parts by weight of titanium oxide having an average particle size of 1 μm (Example 15) was used in the same manner as in Example 13. The results are shown in Table 3.

Example 16 Polyvinyl alcohol UP 240G C Unitika (a
100 parts by weight of silica with an average particle size of 4 μm was added to 100 parts by weight of [trade name] manufactured by ), to prepare a rewetting adhesive composition, and a test sample was prepared in the same manner as in Example 1.
Adhesive strength 4 and blocking resistance were determined. The results are shown in Table 3.

Example 17.18 In Example 15, 220 parts by weight of calcium carbonate having an average particle size of 2 μm (Example 16) was used instead of 180 parts by weight of silica.
), 250 parts by weight of activated clay with an average particle size of 1 μm (Example 1
The same procedure as in Example 16 was carried out except that 5) was used. The results are shown in Table 3.

Comparative Example 8 The same procedure as in Example 13 was carried out except that the amount of silica was changed to 70 parts by weight. The results are shown in Table 3.

Comparative Example 9 The same procedure as in Example 13 was carried out except that the amount of silica was changed to 450 parts by weight.

The results are shown in Table 3.

Comparative Example 10 The same procedure as in Example 17 was carried out except that the total amount of calcium carbonate was changed to 80 parts by weight. The results are shown in Table 3.

Comparative Example 11 The same procedure as in Example 17 was carried out except that the amount of calcium carbonate was changed to 400 parts by weight.

The results are shown in Table 3.

[Brief explanation of drawings]

FIGS. 1 to 4 are explanatory diagrams showing examples of different aspects of the postcard system with confidentiality, respectively, and FIGS. 5 to 7 are explanatory diagrams of the folded state of FIGS. 1 to 3. , In the figure, l is the surface adhesive layer, 2 is the back adhesive layer, 3,
3' is a fold line. Patent applicant Totsupan Hiroa Co., Ltd.

Claims (1)

[Scope of Claims] 1. A removable adhesive composition comprising (A) a non-removable adhesive base and (B) a particulate filler that has no affinity for the adhesive base. . 2. A pressure-sensitive adhesive composition or a rewetting adhesive composition containing 100 to 400 parts by weight of component (B) per 100 parts by weight of a pressure-sensitive or rewetting type non-peelable adhesive base. 1
The releasable adhesive composition described. 3 Per 100 parts by weight of heat-sensitive non-peelable adhesive base, (
A releasable adhesive composition according to claim 1, which is a heat-sensitive adhesive composition containing 45 to 100 parts by weight of component B).