JPH04189888A - Pressure-sensitive tacky adhesive agent - Google Patents

Abstract

PURPOSE:To provide a pressure-sensitive adhesive containing a main tacky adhesive agent and a resin having low compatibility to the main agent, suitable as an easily openable tacky adhesive for mail form and effective for the improvement of economic merit. CONSTITUTION:The objective tacky adhesive agent contains (A) a main tacky adhesive agent composed of preferably (i) 5-30 pts.wt. of natural rubber and (ii) 5-30 pts.wt. of a styrene/butadiene rubber and (B) preferably 5-30 pts.wt. of a resin having low compatibility to the component A, e.g. a water-dispersible polymeric polyester, a thermoplastic elastomer, a low-density PE or a vinyl acetate/olefin copolymer.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a pressure-sensitive adhesive, for example, a pressure-sensitive adhesive for use in mail forms that are folded in two, three, etc. and pasted and shipped after recording necessary information. The present invention relates to a pressure-sensitive adhesive suitable as an easy-to-open adhesive.

[Prior art and problems to be solved by the invention] In recent years, mail forms have been used for notifications from financial institutions, government offices, etc., which are printed with necessary information using a printer, etc., then folded into an envelope, etc., and pasted and shipped. A widely used method is to fold the package in three, attach the peripheral edge with a pressure-sensitive adhesive, and when opening the package, cut out three or four sides from the perforation and unfold it. However, when opening this mail form, it is necessary to cut out the peripheral edge from the perforation, which causes the problem of dust generation and a reduction in the effective area of the information recording portion. Furthermore, since this mail form only has the peripheral edges attached, it is treated as a sealed letter under the current postal law, and even if its dimensions were the size of a postcard, it could not be mailed as a cheap postcard.

On the other hand, it is also known that after recording the necessary information, an adhesive film is sandwiched between the sheets, the sheet is folded, and the sheet is pasted.This sheet can be mailed like a postcard. However, this type of film has the disadvantage that it requires a film sandwiching operation and the manufacturing process is complicated.

In order to solve these problems, the applicant first developed a mail form in which a pressure-sensitive adhesive made of styrene-butadiene rubber as a resin component and microsilica dispersed in water is applied to the adhesive surface. (Patent application No. 2-1344)
No. 70). This mail form allows necessary information to be recorded on the adhesive-applied surface using a printer, etc., and the adhesive strength of the pressure-sensitive adhesive to the base material of the mail form makes it possible to reduce the sensitivity when the mail form is folded and pasted. The bonding force between the adhesive and characters printed on the recording side is greater than the adhesive force at the interface between pressure adhesives, and the adhesive force on the non-recording side when folded and attached Because the adhesive strength is greater than that between the pressure-sensitive adhesive and characters, it can be peeled off at the adhesive interface between the pressure-sensitive adhesives without transferring the characters when the package is opened, making it possible to read the information printed on the surface coated with the pressure-sensitive adhesive. It has the advantage of being

However, the above-mentioned mail form coated with a pressure-sensitive adhesive has spot-like sagging portions (referred to as dry tack) after the pressure-sensitive adhesive has been applied and dried.

) remained, and if multiple mail forms coated with adhesive were stacked and stored, their own weight would cause them to stick to each other, resulting in so-called blocking. On the other hand, if the content of microsilica in the pressure-sensitive adhesive is increased, blocking becomes less likely to occur, but the adhesive strength of the adhesive decreases and the adhesive may fall off when rubbed by a printer roll, etc. There were other problems, such as the fact that the mail form could not be folded and attached securely.

The inventor's research also revealed that by reducing the thickness of the adhesive applied to the base material, it is possible to reduce the dry tank without reducing the bonding force of the adhesive to the base material. did. However, even if particles with a particle size of about 1 μm are used as the adhesive main ingredient, particles with a particle size of about 10 μm exist due to secondary aggregation in the state of the adhesive dispersed in water. It was difficult to

Furthermore, with conventional pressure-sensitive adhesives, although the adhesive-coated surfaces stick to each other, there is almost no adhesiveness between the adhesive-coated side and the non-adhesive-coated side, and this tendency becomes especially noticeable when the dry tack is reduced. . For this reason, when using a conventional pressure sensitive adhesive, the adhesive had to be applied to the surface to be adhered in advance.

The present invention has been made in view of the above points, and when used as an adhesive for mail forms, it can reduce the occurrence of dry tack without reducing the adhesive strength (compared to conventional methods).
It does not cause blocking even when stacked in large quantities (that is, it does not stick to the pressure generated when stacking), and the adhesive-coated surfaces adhere strongly to each other and the adhesive interface between the adhesives does not occur. It is an object of the present invention to provide a pressure-sensitive adhesive that can be peeled off and opened by pressing the pressure-sensitive adhesive, and can also adhere to an adhesive-coated surface and an adhesive-uncoated surface when a certain amount of pressure is applied.

[Means to solve the problem]

That is, the pressure-sensitive adhesive of the present invention is characterized by containing an adhesive base agent and a resin having low compatibility with the adhesive base agent. The pressure sensitive adhesive of the present invention comprises 5 to 30 parts by weight of natural rubber, 5 to 30 parts by weight of styrene-butadiene rubber, and these natural rubbers.
Resin 5 to 3 with low compatibility with styrene-butadiene rubber
It is preferable to have a composition consisting of 0 parts by weight.

In the pressure-sensitive adhesive of the present invention, the main adhesive ingredients include styrene-butadiene rubber (hereinafter abbreviated as SBR), natural rubber (hereinafter abbreviated as NR), chloroprene rubber, polyvinyl acetate, polymethyl methacrylate (hereinafter abbreviated as NR), PMMA
It is abbreviated as ), and these can be used as a mixture, but it is preferable to use PMMA in combination with another adhesive main agent rather than using it alone. As the main adhesive agent, it is preferable to use NR, which has a high property of developing adhesiveness under pressure, to which SBR or PMMA is added for the purpose of enhancing the anchoring effect. As the adhesive base agent, the particle size is usually 0.1 to 3.
Fine particles of I# size are used. The proportion of the adhesive main agent in the pressure sensitive adhesive is usually about 15 to 40% by weight. The pressure-sensitive adhesive is made into an emulsion by dispersing the above-mentioned adhesive main agent together with an emulsifier and the like in a solvent such as water.

The adhesive of the present invention can prevent secondary aggregation of the adhesive base when it is made into an emulsion by adding a resin having low compatibility with the adhesive base. Examples of resins with low compatibility with the adhesive main agent include water-dispersible polymeric polyesters, thermoplastic elastomers, low molecular weight polyolefins such as low density polyethylene, ionomers, vinyl acetate-olefin copolymers, and the like. These resins have Tg=30~80″C1 average molecular weight 10000
-25,000 cps and a viscosity of 2 (1-20,000 cps) are preferable.The resin having low compatibility with the adhesive base material is preferably contained in an amount of 10 to 40% by weight in the adhesive.

The adhesive of the present invention includes 5 to 50 parts by weight of the above NR, 5B
Preferably, it contains 5 to 30 parts by weight of R and 5 to 30 parts by weight of a resin having low compatibility with these adhesive base ingredients.If PMMA is further added as an adhesive base to these as necessary, 10 parts by weight or less of PMMA should be added. is preferred.

The adhesive of the present invention may optionally contain ultrafine powdered silicic acid,
Synthetic zeolite, activated alumina gel, microsilica such as silica gel, and waxes such as polyethylene wax and Karnauha wax can be added. Furthermore, additives such as ultraviolet absorbers, ammonia, and ethanolamine may be added if necessary.

The adhesive of the present invention is mainly suitable as an adhesive for mail forms, but it is also suitable for adhesives other than mail forms, such as for adhesives for cards that are peeled off after printing, such as cards in card-attached printing paper. It can be used for.

〔Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 A pressure sensitive adhesive (viscosity 3500 cps at pH = 9.30°C: adhesive 1a) containing 22% by weight SBR, 9% by weight microsilica, and 69% by weight water, T g =
A polyester emulsion (viscosity at pH = 5.25°C: 300 cps: Toyobo MD-1100) containing 30% by weight of a water-dispersible polyester with a C1 average molecular weight of 20,000 and 15% by weight of an organic solvent,
Adhesives were prepared in which the amounts added were 10% by weight (adhesive lb), 20% by weight (adhesive 1c), 30% by weight (adhesive 1d), and 40% by weight (adhesive 1e). Each adhesive requires polyester emulsion for adhesive 1a! After the addition, the mixture was stirred for 5 minutes using a mixer for adjustment.

Next, the above-mentioned adhesives 1a-1 were applied to the surface of a sheet of high-quality paper for non-impact printers (manufactured by Isumi Kokusaku Bulb: FPLB-3 (70) cut into a sheet three times the size of a postcard (5.6 inches x 12 inches). Six types of adhesives (Adhesive If) in which all of the main adhesive ingredients of Adhesive 1e and Adhesive 1a were replaced with the above-mentioned water-dispersible polyester (adhesive If) were coated with a bar coater with a coating amount of 2 g / rd, 4 g / rrr. A total of 12 types of adhesive-coated sheets were obtained by drying at 25°C for 15 minutes.For each sheet obtained, the presence or absence of dry tack, the presence or absence of blocking, and the presence or absence of peeling of the adhesive due to friction were determined. The test was carried out at a temperature of 25±1°C and a humidity of 70°C.
The test was carried out in a constant temperature chamber adjusted to ±3%. The results are shown in Table 1. In addition, each test method and evaluation criteria are as follows.

■According to TriTac JIS K-5400 (6, 8), place the sample sheet horizontally on a glass plate with the adhesive coated side facing up.
Layer 5 layers of gauze on top of that and 15g/cJ on top of the gauze.
Place a weight with a smooth bottom to apply pressure and leave it for 24 hours, then peel off the gauze and check the stickiness.
Dry tack was determined by the gauze marks left on the adhesive-applied surface. The evaluation was as follows: ◎: No adhesiveness was shown when the gauze was peeled off, and no traces of the gauze remained.

○: There are no traces of gauze and almost no dry tack.

△: No traces of gauze remain, but some dry tack is observed.

×...Dry tack remains strong.

And so.

■Blocking Layer the adhesive coated sides of two sheets coated with the same adhesive, and use SUS Pro and King Tester to measure 20g.
After applying a pressure of /cIII and leaving it for 24 hours, one of the two stacked sheets was lifted and the adhesion state of the two sheets was judged. Evaluation: ◎...No blocking.

O: There is almost no blocking and the film is easily peeled off.

△...There is some bronching, but there is no problem in practical use.

×... Great blocking.

And so.

■ Peeling of adhesive by friction Position the adhesive coated sheet so that the rotational axis direction of a smooth-surfaced 345C roll (100mm diameter) is perpendicular to the longitudinal direction of the adhesive coated sheet, and The adhesive side of the sheet coated with adhesive is brought into contact with the sheet, and both ends of the sheet are fixed so that a pressure of 100 g/cm is applied to the sheet, and the roll is rotated at 40 rpm for 2 hours. The presence or absence of peeling of the agent was determined. The evaluation is ◎・
...No evidence of adhesive peeling is observed.

○: Almost no evidence of peeling of the adhesive is observed.

△...There is some evidence of peeling of the adhesive.

And so.

■Adhesiveness and peeling surface condition (adhesive coated sides) and adhesive coated side of each sheet Riko Canon Copy Machine (NP-
4835), all of the notebooks had good printing suitability. After printing, each sheet was folded into three folds so that the adhesive-coated surfaces overlapped, and the sealing machine (Nia 000U manufactured by Dai Nippon Printing Co., Ltd.) was pressurized with a gear of 7 to approximately 801 to make the adhesive-coated surfaces stick. Ta. 1 c of the adhesive side of the obtained postcard-like sheet
It was peeled off at a speed of m/sec, and the adhesive strength and the absence of printing transfer on the peeled surface were determined. Evaluation: ◎ Good adhesion, no transfer of print.

○: Adhesiveness is good, and there is almost no transfer of printing.

...Adhesion is good, but some transfer of printing is observed.

Δ: Adhesiveness is good, but there is some transfer of printing.

×...Weak adhesiveness.

M... Adhesiveness is good, but the printing transfer is large.

Closed. The results are also shown in Table 1.

■ Adhesiveness and condition of peeling surface (adhesive-coated side and non-adhesive side) Furthermore, the adhesive-coated side of each sheet After printing in the same manner as above, paper with no adhesive applied to the adhesive-coated side The roll gap of the sealing machine was adjusted to 50μ, and the adhesive-coated sheet and paper were pressed together, and the adhesiveness of both and the presence or absence of transfer of print were evaluated. Evaluation: ◎: Very high adhesion to non-adhesive coated paper, no transfer of print after peeling.

○: Good adhesion to non-adhesive coated paper and no transfer of print.

...Adhesiveness with non-adhesive coated paper, no transfer of print.

△...Weak adhesion to non-adhesive coated paper.

×: Almost no adhesion to non-adhesive coated paper.

And so. The results are also shown in Table 1.

Example 2 33% by weight of NR, 7% by weight of microsilica, 6% of water
The same polyester emulsion as in Example I was added to a pressure-sensitive adhesive (viscosity 3400 cps at pt+ = 9.30'C: adhesive 2a) containing 0% by weight (10% by weight).
Adhesive 2b), 20% by weight (Adhesive 2c), 30% by weight
(Adhesive 2d) and 40% by weight (Adhesive 2e) were prepared. Next, on the same sheet surface as in Example 1, six types of adhesives, including the above-mentioned adhesives 2a to 2e and adhesive 2a in which all of the main adhesive ingredients were replaced with water-dispersible polymeric polyester (adhesive 2f), were coated with a bar coater. The sheets were coated so that the dry coating amount was 2 g/rri and 4 g/bo, and dried at 25° C. for 15 minutes to obtain a total of 12 types of adhesive-coated sheets. For each of the obtained sheets, tests were conducted in the same manner as in Example 1 to determine the presence or absence of a dry tank, the presence or absence of pro and king, and the presence or absence of peeling of the adhesive due to friction. The results are shown in Table 2. Further, when each sheet was printed in the same manner as in Example 1, all sheets had good printing suitability. After printing, each sheet was folded in three so that the adhesive-coated surfaces overlapped and pasted, and then peeled off in the same manner as in Example 1, and the adhesive strength and the presence or absence of transfer of print on the peeled surface were determined. Furthermore, in the same manner as in Example 1, tests were conducted on the adhesion to non-adhesive-coated paper and the transferability of printing. The results are also shown in Table 2.

Example 3 15% by weight SBR, 15% by weight NR, 1% PMMA
Adhesive containing 5% by weight of microsilica and 64% by weight of water (pH = 8.5. Viscosity at 30°C: 320% by weight)
Qcps: The same polyester emulsion as in Example 1 was added to Adhesive 3a') in an amount of 10% by weight (Adhesive 3b), 20% by weight (Adhesive 3c), 30% by weight (Adhesive 3d), 40% by weight. An adhesive was prepared in which the amount of adhesive added was adjusted to % by weight (adhesive 3e). Next, on the surface of the same sheet as in Example 1, six types of adhesives were applied: the above-mentioned adhesives 3a to 3e, and the adhesive 3a in which all of the main adhesive ingredients were replaced with water-dispersible polymeric polyester (adhesive 3f). - Coated with a coater so that the dry coating amount was 2 g/m, 4 g#+() and dried at 25°C for 15 minutes to obtain a total of 12 types of adhesive-coated sheets. For each sheet, tests were conducted on the presence or absence of a dry tank, the presence or absence of protonking, and the presence or absence of adhesive peeling due to friction in the same manner as in Example 1.The results are shown in Table 3. When printing was carried out in the same manner as in Example 1, all sheets had good printing properties.After printing, each sheet was folded in thirds so that the adhesive coated surfaces overlapped and pasted together.
It was peeled off in the same manner as above, and the adhesive strength and the presence or absence of transfer of printing on the peeled surface were determined. Furthermore, in the same manner as in Example 1, tests were conducted for adhesion to non-adhesive-coated paper and transferability of printing.

The results are also shown in Table 3.

Example 4 28% by weight of NR, 3% by weight of SBR, 2% of vinyl acetate
A pressure-sensitive adhesive containing 1% by weight of PMMA, 6% by weight of microsilica, and 60% by weight of water (pH = 8.5.3
Viscosity at 0°C: 3500 cps: The same polyester emulsion as in Example 1 was added to adhesive 4a) in an amount of 10% by weight (adhesive 4b) and 20% by weight (adhesive 4C).
, 30% by weight (adhesive 4d), 40% by weight (adhesive 4e)
) was prepared. Next, on the same sheet surface as in Example 1, six types of adhesives, including the above-mentioned adhesives 4a to 4e and adhesive 4a in which all of the main adhesive ingredients were replaced with water-dispersible polymeric polyester (adhesive 4f), were coated with a bar coater. The coating amount when dry is 2 g/rrr, 4 g/
A total of 12 types of adhesive-coated sheets were obtained by applying the adhesive in a uniform manner and drying it at 25°C for 15 minutes. Each sheet obtained was tested in the same manner as in Example 1 to determine the presence or absence of dry tack, the presence or absence of blocking, and the presence or absence of peeling of the adhesive due to friction. The results are shown in Table 4. Further, when each sheet was printed in the same manner as in Example 1, all sheets had good printing suitability. After printing, each sheet was folded in three so that the adhesive-coated surfaces overlapped and pasted, and then peeled off in the same manner as in Example 1, and the adhesive strength and the presence or absence of transfer of print on the peeled surface were determined. Furthermore, in the same manner as in Example 1, tests were conducted for adhesion to non-adhesive-coated paper and transferability of dark characters. The results are also shown in Table 4.

Example 5 22% by weight SBR, 3% by weight polyethylene wax
, a pressure sensitive adhesive containing 7% by weight of microsilica and 68% by weight of water (viscosity at pH = 9.30°C: 500 cps)
: The same polyester emulsion as in Example 1 was added to adhesive 5a) in an amount of 10% by weight (adhesive 5b), 20% by weight (adhesive 5c), 30% by weight (adhesive 5d), 40% by weight.
An adhesive was prepared in which the amount of adhesive added was adjusted to % by weight (adhesive 5e).

Next, the above adhesives 5a to 5 are applied to the surface of the same sheet as in Example 1.
Six types of adhesives, including Adhesive 5e and Adhesive 5a in which all of the main adhesive ingredients were replaced with water-dispersible polymeric polyester (adhesive 5f), were coated with a bar coater in a dry coating amount of 2 g/rr.
4 g/rd and dried at 25° C. for 15 minutes to obtain a total of 12 types of adhesive-coated sheets. Each sheet obtained was tested in the same manner as in Example 1 to determine the presence or absence of dry tack, the presence or absence of bronking, and the presence or absence of peeling of the adhesive due to friction. The results are shown in Table 5. Further, when each sheet was printed in the same manner as in Example I, all sheets had good printing suitability.

After printing, place each sheet 3 so that the adhesive coated sides overlap.
After folding and pasting, it was peeled off in the same manner as in Example 1, and the adhesive strength and the presence or absence of transfer of printed characters on the peeled surface were determined. Furthermore, in the same manner as in Example 1, tests were conducted for adhesion to non-adhesive-coated paper and print transferability. The results are also shown in Table 5.

Example 6 A pressure sensitive adhesive containing 31% by weight of SBR and 69% by weight of water (
p) 1=9.3500 cpS viscosity at 30°C: Adhesive 6a), Tg=40°C1 average molecular weight 20000
A polyester emulsion (pH=
5. Viscosity at 25°C: 30Qcps: Toyobo: M
D-1100) in an added amount of 10% by weight (adhesive 6b)
, 20% by weight (adhesive 6c), 30% by weight (adhesive 6d)
) and 40% by weight (adhesive 6e) was prepared. Next, on the surface of the same sheet as in Example 1, six types of adhesives were barred, including the above-mentioned adhesives 6a to 6e and adhesive 6a in which all of the main adhesive ingredients were replaced with water-dispersible polymeric polyester (adhesive 6f). It was coated with a coater so that the dry coating amount was 2 g/ni, 4 g/rf, and dried at 25°C for 15 minutes to obtain a total of 12 types of adhesive-side coated sheets. Each sheet obtained was tested in the same manner as in Example 1 to determine the presence or absence of dry tack, the presence or absence of bronking, and the presence or absence of peeling of the adhesive due to friction. The results are shown in Table 6. Further, when each sheet was printed in the same manner as in Example 1, all sheets had good printing suitability. After printing, each sheet was folded in three so that the adhesive-coated surfaces overlapped and pasted, and then peeled off in the same manner as in Example 1, and the adhesive strength and the presence or absence of transfer of print on the peeled surface were determined. Furthermore, in the same manner as in Example 1, tests were conducted for adhesion to non-adhesive-coated paper and print transferability. The results are also shown in Table 6.

Example 7 The adhesive 1a used in Example 1 was added as an emulsion of water-dispersible polyester with Tg=67°C1 average molecular weight 1
5000, containing 34% solids and 10% organic solvent (viscosity 30000 at pH=6.25°C)
cps: manufactured by Toyobo: MD-1200) at 10% by weight (Adhesive 7b), 20% by weight (Adhesive 7c), 30% by weight (
Adhesive 7d), an adhesive added at 40% by weight (Adhesive 7e), and an adhesive in which all of the main adhesive of Adhesive 1a was replaced with the above water-dispersible polymer polyester (Adhesive 7f). A pressure-sensitive adhesive was prepared and the same test as in Example 1 was conducted. The results are shown in Table 7.

Example 8 The adhesive 2a used in Example 2 was added as an emulsion of water-dispersible polyester with Tg=67°C1 average molecular weight 11
5000, containing 25% solids and 10% organic solvent CpH-5, viscosity at 25°C 60cps
: Toyobo MD-1220) 10% by weight (adhesive 8
b), 20% by weight (adhesive 8c), 30% by weight (adhesive 8d), and 40% by weight (adhesive 8e) of the adhesive and the adhesive topcoat of adhesive 2a were all added to the above water. Replaced with dispersible polymer polyester (adhesive 8f)
Five types of adhesives were prepared and the same test as in Example 2 was conducted. The results are shown in Table 8.

Example 9 The adhesive 3a used in Example 3 was added as an emulsion of water-dispersible polyester with Tg=62°C1 average molecular weight 1
0000, containing 30% solids and 15% organic solvent (viscosity 200cp at pH=3.25°C)
s: Toyobo +MD-1250) was added at 10% by weight (adhesive 9b), 20% by weight (adhesive 9c), 30% by weight (adhesive 9d), and 40% by weight (adhesive 9e). Adhesive and Adhesive 3a in which all of the main adhesive ingredients are replaced with the above water-dispersible polymer polyester (Adhesive 9f)
) were prepared and the same test as in Example 3 was conducted. The results are shown in Table 9.

Example 10 40% by weight of polyvinyl acetate, 5% by weight of NR, 5% by weight of water
The same water-dispersible polymer polyester emulsion as in Example 1 was added to a pressure-sensitive adhesive containing 5% by weight (viscosity 3800 cps at pH = 8.9.30°C: Adhesive 10a) in an amount of 10% by weight (adhesive 10a). 10b), 20% by weight (Adhesive 10c), 30% by weight (Adhesive 10d), 40% by weight (
Six types of adhesives were prepared, including an adhesive added to give Adhesive 10e) and one in which all of the main adhesive of Adhesive 10a was replaced with water-dispersible polymeric polyester (polyester emulsion) (Adhesive 10f). Then, the same test as in Example 1 was conducted. The test pattern was printed on the adhesive-coated surface of the sheet coated with these adhesives using a dot impact printer (Nippon Denki type: PC-PR201V).
) was used. The results are shown in Table 10.

Example 11 Pressure-sensitive adhesive containing 45% by weight of polyvinyl acetate and 55% by weight of water (p) Viscosity at l=8.8.30°C 390
0 cps: The same water-dispersible polymer polyester emulsion as in Example 1 was added to the adhesive 11a) in an amount of 10% by weight.
(Adhesive 11b), 20% by weight (Adhesive 11c), 30
Weight% (Adhesive 11d), 40% by weight (Adhesive 11e)
An adhesive in which S is added so that the adhesive 11a is replaced with water-dispersible polymeric polyester (polyester emulsion) (adhesive 11f).
Six types of adhesives were prepared and the same tests as in Example 1 were conducted. A test pattern was printed on the adhesive-coated surface of the sheet coated with these adhesives using a dot-impact printer similar to that used in Example 10. 11th result
Shown in the table.

Example 12 Pressure-sensitive adhesive containing 43% by weight of polyvinyl acetate, 5% by weight of microsilica, and 52% by weight of water (pH-8, 8, 3)
Viscosity at 0°C: 3800 cps: The same water-dispersible polymer polyester emulsion as in Example 1 was added to adhesive 12a) in an amount of 10% by weight (adhesive 12b), 20% by weight (adhesive 12c), and 30% by weight. (Adhesive 12d), 4
Six types of adhesives were added: 0% by weight (Adhesive 12e) and one in which all of the main adhesive of Adhesive 12a was replaced with water-dispersible polymeric polyester (polyester emulsion) (Adhesive 12f). An adhesive was prepared and the same test as in Example 1 was conducted. A test pattern was printed on the adhesive-coated surface of the sheet coated with these adhesives using a dot-impact printer similar to that used in Example 10. The results are shown in Table 12.

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・Hill---1111---------------------- [Effects of the Invention] As explained above, when the pressure sensitive adhesive of the present invention is used as an adhesive for mail forms, the trial Due to the small number of tanks, the mail forms do not bronch against each other under the pressure of stacking the mail forms, and the adhesive strength when pasting the mail forms is excellent, and the bonding strength of the adhesive to the mail form base material is improved. Because of its superior properties, there is no risk of the adhesive peeling off due to friction during printing. Furthermore, in the mail form using the adhesive of the present invention, when the mail form is pasted and sealed and then peeled off again, the information printed on the adhesive coated surface is not transferred and is reliably peeled off at the interface between the adhesives. Printed information can be reliably read. In addition, the pressure-sensitive adhesive of the present invention can adhere to the adhesive-coated surface and the non-adhesive-coated surface by applying high pressure, so it is not necessary to apply the adhesive to the entire adhesive surface, which is economical. can be improved.

Claims (2)

[Claims] (1) A pressure-sensitive adhesive characterized by containing an adhesive base agent and a resin having low compatibility with the adhesive base agent. (2) 5 to 30 parts by weight of natural rubber as an adhesive base agent and 5
2. The pressure-sensitive adhesive according to claim 1, comprising 30 parts by weight of styrene-butadiene rubber and 5 to 30 parts by weight of a resin having low compatibility with the adhesive base agent.