JP2001240834A - Pressure-sensitive adhesive composition and pressure- sensitive adhesive sheet using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain both a pressure-sensitive adhesive composition having both a firm fixability on a paper and a high cohesive strength of an adhesive film without causing the wear or falling off of the adhesive during running through a printing machine or printer, etc., and a pressure-sensitive sheet using the pressure-sensitive adhesive composition. SOLUTION: This pressure-sensitive adhesive composition is obtained by compounding an adhesive base prepared by compounding a methyl methacrylate graft-copolymerized natural rubber-based adhesive mass with a specific amount of a specified styrene-rich SBR latex and/or a polystyrene emulsion and/or a styrene-acrylic copolymer emulsion with respective specific amounts of an oil absorbing particulate filler and a spherical particulate filler exhibiting the nonaffinity for the adhesive base. The pressure-sensitive sheet is obtained by using the pressure-sensitive adhesive composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet using the same, and more particularly, to applying a predetermined pressure to paper, synthetic paper, a synthetic film of polyethylene or the like. And a pressure-sensitive adhesive sheet using such a pressure-sensitive adhesive composition.

[0002]

2. Description of the Related Art Conventionally, in a pressure-sensitive adhesive sheet, a pattern which is in contact with the pressure-sensitive adhesive sheet when the sheets are superimposed on each other so that the superposed surfaces of the pressure-sensitive adhesive sheet and another sheet to be adhered adhere to each other. An adhesive portion of the pressure-sensitive adhesive is provided on the entire surface, a specific portion, or a line of the superposed surface of the pressure-sensitive adhesive sheet. Although this pressure-sensitive adhesive does not adhere in a normal state, the superposed surfaces are brought into contact with each other and a predetermined pressure is applied so that the superposed surfaces are firmly adhered to each other. Depending on the type and the degree of pressure, permanent adhesiveness is realized.

Conventionally, pressure-sensitive adhesives used in this kind of pressure-sensitive adhesive sheet generally include a methyl methacrylate graft copolymer natural rubber pressure-sensitive adhesive and a methyl methacrylate / styrene graft copolymer natural rubber pressure-sensitive adhesive. It is included as a main component. However, a pressure-sensitive adhesive containing a methyl methacrylate graft copolymer natural rubber-based adhesive as a main component,
Both the fixing property to a base sheet such as paper and the cohesive force of an adhesive film are weak, and there is a problem that the adhesive is worn and falls off while running a printing machine or a printer.

[0004]

SUMMARY OF THE INVENTION A first object of the present invention is to provide a pressure-sensitive adhesive composition containing a methyl methacrylate graft copolymerized natural rubber-based pressure-sensitive adhesive as a main component, which has solved the conventional problems. Both the fixability to the base sheet such as paper and the cohesive force of the adhesive film are strong, so that the adhesive does not wear or fall off while running a printing machine or printer.
For example, when making an envelope by firmly bonding predetermined ends of envelope upper paper and envelope lower paper, or when firmly bonding predetermined ends of each sheet of carbonless paper composed of multiple sheets, etc. A second object of the present invention is to provide a pressure-sensitive adhesive sheet using such a pressure-sensitive adhesive composition. .

[0005]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, a specific styrene-rich SBR latex, a polystyrene emulsion, a specific styrene-rich SBR latex, The problem was solved by using a pressure-sensitive adhesive composition in which a specific amount of a specific type of fine-grained filler exhibiting non-affinity was mixed with an adhesive base in which a specific amount of a styrene / acrylic copolymer emulsion was mixed. They have found that they can be solved, and have completed the present invention.

That is, the pressure-sensitive adhesive composition according to the first aspect of the present invention is applied to a superposed surface of a sheet, and forms a bonded portion which does not adhere in a normal state by a drying treatment. A pressure-sensitive adhesive for firmly adhering the superposed surfaces by contacting each other and applying a predetermined pressure, wherein a styrene-containing material is added to a solid content of 100 parts by mass of a methyl methacrylate graft natural rubber-based adhesive. An adhesive base 10 containing a styrene-rich SBR latex and / or a polystyrene emulsion and / or a styrene-acrylic copolymer emulsion having an amount of 70 to 95% and a solid content of 5 to 50 parts by mass.
The oil-absorbing fine-grained filler and the spherical fine-grained filler having incompatibility with the adhesive base are each in the range of 10 to 40 parts by mass, and the total amount of both is 2 to 0 parts by mass.
It is characterized by being blended so as to be 0 to 60 parts by mass.

According to the pressure-sensitive adhesive composition of the first aspect of the present invention, the styrene-rich SBR latex and / or the polystyrene emulsion and / or the styrene-acrylic emulsion are added to the methyl methacrylate graft copolymerized natural rubber-based pressure-sensitive adhesive. Use a pressure-sensitive adhesive composition in which a specific amount of a specific type of fine-grained filler exhibiting non-affinity is mixed with an adhesive base in which the copolymer emulsion is mixed so that the solid content is a specific amount. Therefore, the adhesive is applied to a predetermined portion of the superposed surface of the sheet, and a drying process is performed to form an adhesive portion that does not adhere in a normal state (high blocking resistance) even when the superposed surfaces are brought into contact with each other. By bringing the mating surfaces into contact with each other and applying a predetermined pressure, the mating surfaces can be firmly bonded to each other. Among the fine particulate fillers, the spherical fine particulate filler contributes to the above-described blocking resistance, and the oil-absorbing fine particulate filler is a releasing material such as silicone oil from a printing machine or a printer on the surface of the bonding portion. Has the effect of preventing oil from absorbing oil even if it migrates and adheres. The pressure-sensitive adhesive composition according to claim 1 of the present invention has both strong fixability to a base sheet such as paper and a strong cohesive force of an adhesive film. Does not wear or fall off.

The pressure-sensitive adhesive composition according to claim 2 of the present invention is the pressure-sensitive adhesive composition according to claim 1, wherein the oil-absorbing fine-particle filler is silica gel having an average particle diameter of 1 to 10 μm, It is characterized in that the spherical fine-particle filler is starch having an average particle size of 10 to 20 μm. The pressure-sensitive adhesive composition according to claim 2 of the present invention is excellent in blocking resistance and oil absorption.

According to a third aspect of the present invention, there is provided a pressure-sensitive adhesive sheet having an adhesive portion of the pressure-sensitive adhesive composition according to the first or second aspect at a predetermined portion of the superposed surface of the base sheet. It is characterized by becoming.

The pressure-sensitive adhesive sheet according to claim 3, wherein an adhesive portion which does not adhere in a normal state (has high blocking resistance) even when the superposed surfaces are brought into contact with each other is formed. By applying a predetermined pressure by
It can be firmly bonded through the bonding portion.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The pressure-sensitive adhesive composition of the present invention does not adhere in a normal state even when the superposed surfaces are brought into contact with each other, and forms an adhesive portion that can be adhered by applying pressure by bringing the superposed surfaces into contact with each other. A styrene-rich SBR latex, a polystyrene emulsion, or a styrene-acryl copolymer emulsion, based on 100 parts by mass of a solid content of a methyl methacrylate graft copolymerized natural rubber-based adhesive as an adhesive base. Alternatively, a mixture is used in which two or more kinds (hereinafter, referred to as a styrene-acryl copolymer emulsion or the like) are blended so that the solid content is 5 to 50 parts by mass. The pressure-sensitive adhesive composition of the present invention is obtained by mixing 20 to 60 parts by mass of a non-affinity fine-particle filler with 100 parts by mass of the adhesive base. The fine-grained filler is composed of an oil-absorbing fine-grained filler and a spherical fine-grained filler, each in the range of 10 to 40 parts by mass, and the total amount of both is 20 to 60 parts by mass. It is important.

The methyl methacrylate graft copolymerized natural rubber-based pressure-sensitive adhesive used in the pressure-sensitive adhesive composition of the present invention is a natural rubber-based pressure-sensitive adhesive graft-copolymerized with methyl methacrylate (based on 100 parts by weight of natural rubber). For example, a graft copolymerized with about 10 to 40 parts by mass of methyl methacrylate), and a natural rubber latex conventionally used as a base of a natural rubber-based pressure-sensitive adhesive can be used.

The styrene-rich SBR latex used in the pressure-sensitive adhesive composition of the present invention is a synthetic rubber latex generally used as a component of an adhesive, and is an emulsion in which styrene-rich SBR is dispersed in an aqueous solvent. It is. The styrene content is 70-95%, preferably 80-95%. Less than 70% or 95%
If the ratio exceeds the above range, the fixability to a base sheet such as paper and the cohesive force of the adhesive film may not be improved.

Specific examples of commercially available styrene-rich SBR latex used in the pressure-sensitive adhesive composition of the present invention include Nipol 2507H (Zeon Corporation), Asahi Kasei Latex L-1638 (Asahi Kasei Corporation), JSR synthetic rubber latex 0602 (JSR
Co., Ltd.).

The polystyrene emulsion used in the pressure-sensitive adhesive composition of the present invention is a synthetic latex generally used as a component for impregnation, reinforcement of other latex, etc., and an emulsion obtained by dispersing polystyrene in an aqueous solvent. It is.

Specific examples of commercially available polystyrene emulsions used in the pressure-sensitive adhesive composition of the present invention include, for example, Nipol LX-303 (Zeon Corporation),
Asahi Kasei Latex L-8801 (Asahi Kasei Corporation), C-
20 (Showa High Polymer Co., Ltd.).

The styrene / acrylic copolymer emulsion used in the pressure-sensitive adhesive composition of the present invention is a synthetic latex generally used as a component for impregnation, paint, paper processing, etc., and is a styrene / acrylic copolymer. Is an emulsion in which is dispersed in an aqueous solvent.

Specific examples of commercially available styrene / acrylic copolymer emulsions used in the pressure-sensitive adhesive composition of the present invention include, for example, Polytron F manufactured by Asahi Kasei Corporation.
-2000, F-830, F-2430, F320, F
324, Polysol AM-230 manufactured by Showa Polymer Co., Ltd.
0, AP-6730, AT-2000 and the like.

An emulsifier is required to stabilize the dispersion of particles such as a styrene / acrylic copolymer emulsion, and this emulsifier is generally rosin soap,
Anionic surfactants such as naphthalene sulfonate, fatty acid soap, and alkylbenzene sulfonate are used.

If necessary, a synthetic resin emulsion can be mixed with a mixture of a methyl methacrylate graft copolymerized natural rubber-based pressure-sensitive adhesive and a styrene / acrylic copolymer emulsion. Examples of the synthetic resin emulsion include a polyvinyl acetate emulsion, a vinyl acetate-ethylene copolymer emulsion, a polyacrylate emulsion, and a polyvinyl chloride emulsion. In order to stabilize the dispersion of these synthetic resin emulsions, the above-mentioned emulsifier can be used. This synthetic resin emulsion has a glass transition point of -20.
C. to 10.degree. C. are preferred.

The mixing ratio of the styrene / acrylic copolymer emulsion or the like is such that one or more of these solid contents is 5 to 50 per 100 parts by mass of the solid content of the methyl methacrylate graft copolymerized natural rubber adhesive. It is blended so as to be parts by mass, preferably 10 to 50 parts by mass.

In the present invention, methyl methacrylate grafted to natural rubber and styrene / acrylic copolymer emulsion are blended so that the total amount thereof is in the range of 20 to 60 parts by mass (solid content). Is preferred.

The mixing ratio of the methyl methacrylate graft copolymer natural rubber-based adhesive and the styrene / acrylic copolymer emulsion depends on the adhesive strength of the bonding portion and the fixability to a base sheet made of a material such as paper or synthetic paper. Therefore, it is necessary to adjust it appropriately because it affects the balance with the cohesive force of the adhesive film and the adhesive film. If the solid content of the styrene / acrylic copolymer emulsion is less than 5 parts by mass and the amount of the methyl methacrylate graft copolymerized natural rubber-based pressure-sensitive adhesive is excessive, the fixability of the adhesive layer to the base sheet surface is reduced and abrasion resistance is reduced. Poor sex,
Conversely, when the solid content of the styrene / acrylic copolymer emulsion or the like exceeds 50 parts by mass, the abrasion resistance is inferior. Therefore, the mixing ratio of the methyl methacrylate graft copolymer natural rubber-based pressure-sensitive adhesive and the styrene / acrylic copolymer emulsion must be in the above range.

The thus obtained adhesive base comprising a mixture of a methyl methacrylate graft copolymerized natural rubber-based adhesive and a styrene / acrylic copolymer emulsion or the like may be used, if desired, in a conventional adhesive. Additives
For example, tackifiers, viscosity modifiers, antioxidants, stabilizers,
A coloring agent or the like can be added.

In the pressure-sensitive adhesive composition of the present invention, a fine particle filler having incompatibility with the adhesive base is blended. As the fine particle filler, those having a small affinity with the adhesive base, and contributing to the blocking resistance, and a spherical fine particulate filler, such as silicone oil or the like from a printing machine or a printer on the surface of the bonding portion An oil-absorbing fine-grained filler having an effect and an effect of preventing the adhesive from being adversely affected by absorbing oil even when the releasable substance migrates and adheres is used in combination.

Examples of the spherical fine particulate filler include various types of starch, fine spherical acrylic resin, fine spherical methacrylic resin, fine spherical polyethylene, spherical alumina, glass powder,
Shirasu balloon, and the like. These spherical fine particle fillers may be used alone or in combination of two or more.

Among these, starch having an average particle size of 10 to 20 μm is excellent in blocking resistance and can be preferably used in the present invention.

Examples of the oil-absorbing fine-particle filler include natural zeolites, synthetic zeolites, silica gel, calcium carbonate, activated clay and the like. These oil-absorbing fine particle fillers may be used alone or in combination of two or more.

Among these, silica gel having an average particle size of 1 to 10 μm is preferably used in the present invention because of its excellent oil absorbency.

Further, in the pressure-sensitive adhesive composition of the present invention, the oil-absorbing fine-grained filler and the spherical fine-grained particles exhibiting incompatibility with the adhesive base per 100 parts by mass of the adhesive base. Each of the fillers is in the range of 10 to 40 parts by mass, and the total amount of both is 20 to 60 parts by mass, preferably 25 to 60 parts by mass.
60 parts by mass, more preferably 30 to 55 parts by mass. If the amount of the fine particle filler is too small at less than 20 parts by mass, the blocking resistance may decrease,
On the other hand, if it exceeds 60 parts by mass, the adhesive strength will be too low, and sufficient tackiness will not be exhibited. When the amount of the oil-absorbing fine-grained filler and the amount of the spherical fine-grained filler are less than 10 parts by mass, respectively, the blocking resistance and oil absorption may be insufficient, and when the amount exceeds 40 parts by mass, the adhesive strength may be too low. .

The pressure-sensitive adhesive composition of the present invention is applied to a predetermined portion of the superposed surface of the base sheet by a coating means such as a gravure coater, flexo, air knife coater, bar coater or the like, and does not adhere in a normal state by a drying treatment. By forming an adhesive portion and bringing the overlapping surfaces into contact with each other and applying a predetermined pressure, the overlapping surfaces can be firmly bonded. The pressure-sensitive adhesive composition of the present invention may be used, for example, when making an envelope by firmly bonding predetermined ends of an envelope upper paper and an envelope lower paper, or of each sheet of carbonless paper composed of a plurality of sheets. It can be suitably used when firmly bonding a predetermined end portion.

Next, as a substrate sheet to which the pressure-sensitive adhesive composition of the present invention is applied, synthetic paper or a synthetic film of polyethylene, polyethylene terephthalate, polypropylene, vinyl chloride or the like is used in addition to ordinary paper. You can also. When using these synthetic films, the surface of the base sheet is preferably subjected to a surface treatment such as a mat treatment or a corona treatment. In addition, the amount of the pressure-sensitive adhesive composition applied to the base sheet surface is due to the adhesiveness of the bonded portion.
1 to 30 g / m ^2, preferably from 3 to 20 g / m ^2, more preferably preferably set to 5 to 15 g / m ^2. Further, by applying pressure to the formed adhesive portion with a pressure roller, the blocking resistance can be further improved.

Next, the structure of the pressure-sensitive adhesive sheet of the present invention will be described in detail with reference to the accompanying drawings. Here, FIG.
Is an explanatory view showing the pressure-sensitive adhesive sheet of the present invention, and FIG.
FIG. 1 is an explanatory diagram showing a pressure-sensitive adhesive sheet of the present invention in a cross section along a longitudinal direction. 1 in FIG. 1 is an example of a continuous envelope.
When a telecommunications company sends a delivery to a large number of customers, it sends the delivery, such as an invoice and a contact slip, to the customer in an envelope that contains information such as the name of the customer on the receiving side. A continuous envelope 1 in which a plurality of envelopes are continuous is used so that information can be efficiently written on the envelope, and the continuous envelope 1 is loaded into a printer and stored in a computer or the like in advance. The information is output on a printer.

As shown in FIG. 1, a continuous envelope 1 is a combination of a continuous envelope upper paper 2 and a continuous envelope lower paper 3 (a pressure-sensitive adhesive sheet of the present invention). The paper 2 has a paper transport hole 4 at both ends and a unit envelope upper paper 6 having an information printing section 5 on the front side connected to a separation section 7 formed of perforations or the like. The continuous envelope lower sheet 3 is formed by connecting unit envelope lower sheets 8 each having a paper transfer hole 4 at both ends at a separation section 7 formed of perforations or the like. Then, the unit envelope upper paper 6 and the unit envelope lower paper 8 are superposed with the same size and overlapped, and two sides of the inner side from the paper transport hole 4 and the direction perpendicular to the paper transport hole 4 are arranged. Are bonded to each other through the bonding portion 10 formed on the continuous envelope upper paper 2 and the continuous envelope lower paper 3.
An envelope 9 whose sides are bonded and whose one side is open is formed.
Then, the continuous envelope 1 having such a structure is mounted on an electrostatic printer (not shown) which is excellent in quietness and high in printing efficiency, and prints information such as a customer name on the information printing section 5 of the unit envelope 2. It is supposed to.

As described above, the continuous envelope upper paper 2 and the continuous envelope lower paper 3 (the pressure-sensitive adhesive sheet of the present invention) are lined with a specific portion of the superposed surface so that the superposed surfaces thereof are adhered to each other. 10 comprising the pressure-sensitive adhesive composition of the present invention
Is provided.

Since the adhesive portion 10 made of the pressure-sensitive adhesive composition of the present invention does not adhere in a normal state, the continuous envelope base paper 3
When the continuous envelope upper paper 2 and the continuous envelope upper paper 2 are stacked in a plurality, they are not bonded or blocked, but by applying a strong pressure in a state where the continuous envelope upper paper 2 and the continuous envelope Both are firmly adhered through the ten and are permanently adhered. The adhesive portion 10 has both a high fixability to a base sheet such as paper and a cohesive force of an adhesive film, so that the adhesive portion 10 does not wear out or fall off while running a printing machine or a printer.

[0037]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited to these Examples. (Examples 1 to 10) Natural rubber (NR) as a natural rubber-based pressure-sensitive adhesive grafted with methyl methacrylate (MMA)
100 parts by mass of MMA graft copolymerized natural rubber emulsion (solid content) obtained by mixing 100 parts by mass of MMA and 25 parts by weight of MMA were mixed with a polystyrene emulsion (Nipol LX303, Nippon Zeon Co., Ltd.).
Alternatively, 100 parts by mass of an adhesive base prepared by mixing Asahi Kasei Latex L-8801 (Asahi Kasei Corporation) or C-20 (Showa High Polymer Co., Ltd.) so that the solid content becomes 15 parts by mass or 25 parts by mass. On the other hand, silica gel and starch were blended in the proportions shown in Table 1 to prepare a pressure-sensitive adhesive composition of the present invention. The pressure-sensitive adhesive composition of the present invention is applied to a 110 kg coated paper at a rate of 10 g / m ² by a gravure offset method to form an adhesive portion,
Next, a drying treatment was performed at 120 ° C. for 30 seconds. Silicone oil pressure bonding force of the pressure-sensitive adhesive sheet made in this way,
The blocking resistance and abrasion resistance were evaluated by the following methods, and the evaluation results are shown in Table 1.

(1) Method of measuring silicone oil pressure bonding force: A sample was prepared by cutting the obtained pressure-sensitive adhesive sheet, and a small amount of the sample was applied to the surface of the bonding portion of the sample using an application roll provided with an RI tester. Silicone oil was applied. The pressure (kg / cm ² ) was measured when the samples having a small amount of silicone oil applied to the surface of the bonded portion were overlaid and pressed together for complete permanent bonding. ◎: 30 to 50 (excellent) (because oil is absorbed even if silicone oil is interposed, it can be completely permanently bonded at a low pressure) ○: 50 to 100 (good) (comparison because oil is absorbed even when silicone oil is interposed) Δ: 100 to 150 (OK) (permanent adhesion cannot be achieved unless the pressure is relatively high due to the influence of silicone oil) ×: 150 or more (impossible) (effect of silicone oil) Unless the pressure is particularly high, complete permanent bonding is not possible.)

(2) Blocking resistance The obtained pressure-sensitive adhesive sheet was cut to prepare a sample, which was then overlaid with another sample having no bonded portion, and 500 g
/ Cm ² , and after leaving at 50 ° C. for 30 minutes, the peel strength (gf / 10 mm) was measured. When the blocking resistance (peeling strength) was 2 or less, the result was evaluated as ◎. For the measurement of the peel strength, a tensile tester Autograph AGS50 manufactured by Shimadzu Corporation was used. ◎: Excellent, ○: Good, △: Acceptable, ×: Not Acceptable

(3) Wear Resistance Using a paperboard abrasion tester, the surface of the bonded portion when worn 20 times was visually judged to determine the degree of wear. As a result, the ratio of the broken area of the tested area was 10% or less: 、, 30% or less: 、, 50% or less: Δ, 51% or more: ×. ◎: Excellent, ○: Good, △: Acceptable, ×: Not Acceptable

(Comparative Examples 1 to 6) A pressure-sensitive adhesive composition for comparison was prepared by blending silica gel and / or starch in the proportions shown in Table 2, and was prepared in the same manner as in Example 1. The pressure-sensitive adhesive sheet was evaluated for silicone oil pressure resistance, blocking resistance, and abrasion resistance, and the evaluation results are shown in Table 2.

[0042]

[Table 1]

[0043]

[Table 2]

From Tables 1 and 2, it can be seen that the pressure-sensitive adhesive compositions of the present invention of Examples 1 to 10 are all excellent in silicone oil pressure, blocking resistance and abrasion resistance. It can be seen that any one or more of the pressure-sensitive adhesive compositions of Examples 1 to 6 are inferior.

Examples 11 to 20 Methyl Methacrylate (MMA) Graft Copolymer As a natural rubber-based pressure-sensitive adhesive, 100 parts by weight of natural rubber (NR) and 25 parts by weight of MMA were mixed and obtained by graft copolymerization. For 100 parts by mass (solid content) of MMA graft copolymerized natural rubber emulsion,
Styrene-rich SBR latex (Nipol 2507
H, Nippon Zeon Co., Ltd. or Asahi Kasei Latex L-
1638) was mixed with silica gel and starch at the ratio shown in Table 3 with respect to 100 parts by mass of the adhesive base in which the solid content was 15 parts by mass or 25 parts by mass, and the pressure-sensitive adhesive of the present invention was obtained. A composition was prepared. The pressure-sensitive adhesive sheet obtained in the same manner as in Example 1 was evaluated for silicone oil pressure resistance, blocking resistance, and abrasion resistance. The evaluation results are shown in Table 3.

(Comparative Examples 7 to 12) A pressure-sensitive adhesive composition for comparison was prepared by blending silica gel and / or starch in the proportions shown in Table 4, and was prepared in the same manner as in Example 1. The pressure-sensitive adhesive sheet was evaluated for silicone oil pressure resistance, blocking resistance, and abrasion resistance. Table 4 shows the evaluation results.

[0047]

[Table 3]

[0048]

[Table 4]

From Tables 3 and 4, it can be seen that the pressure-sensitive adhesive compositions of Examples 11 to 20 of the present invention have a silicone oil pressing force,
Both blocking resistance and abrasion resistance are excellent,
On the other hand, the pressure-sensitive adhesive compositions of Comparative Examples 1 to 6 are inferior in any one or more of them.

Examples 21 to 30 Methyl Methacrylate (MMA) Graft Copolymer As a natural rubber-based pressure-sensitive adhesive, 100 parts by weight of natural rubber (NR) and 25 parts by weight of MMA were mixed and graft copolymerized. For 100 parts by mass (solid content) of MMA graft copolymerized natural rubber emulsion,
Styrene / MMA copolymer emulsion [Asahi Kasei Corporation
Polytron F-2000 or F-830 manufactured by Showa High Polymer Co., Ltd.)
0] was mixed with silica gel and starch in the proportions shown in Table 5 with respect to 100 parts by mass of the adhesive base in which the solid content was 15 parts by mass or 25 parts by mass, and the pressure-sensitive adhesive composition of the present invention was obtained. Was prepared. The pressure-sensitive adhesive sheet obtained in the same manner as in Example 1 was evaluated for silicone oil pressure resistance, blocking resistance, and abrasion resistance. Table 5 shows the evaluation results.

(Comparative Examples 13 to 18) Silica gel and / or
Alternatively, starch was blended in the proportions shown in Table 6 to prepare a pressure-sensitive adhesive composition for comparison, and the silicone oil pressure-bonding force and blocking resistance of the pressure-sensitive adhesive sheet obtained in the same manner as in Example 1 , And abrasion resistance, and the evaluation results are shown in Table 6.

[0052]

[Table 5]

[0053]

[Table 6]

From Tables 5 and 6, it can be seen that the pressure-sensitive adhesive compositions of Examples 21 to 30 of the present invention have a silicone oil pressing force,
Both blocking resistance and abrasion resistance are excellent,
On the other hand, it is understood that one or more of the pressure-sensitive adhesive compositions of Comparative Examples 13 to 18 are inferior.

[0055]

The pressure-sensitive adhesive composition according to claim 1 of the present invention is applied to a predetermined portion of a superposed surface of a base sheet such as paper, synthetic paper, or a synthetic film such as polyethylene, and is usually subjected to drying treatment. Form an adhesive part that does not adhere in the state,
A pressure-sensitive adhesive composition containing, as a main component, a methyl methacrylate graft copolymer natural rubber-based pressure-sensitive adhesive capable of firmly adhering the superposed surfaces by bringing the superposed surfaces into contact with each other and applying a predetermined pressure. It has a remarkable effect that the adhesive on the base sheet such as paper and the cohesive force of the adhesive film are both strong, and the adhesive does not wear out or fall off while running a printing machine or printer. Play.
The pressure-sensitive adhesive composition according to claim 1 of the present invention is applied to a predetermined portion of a superimposed surface of a sheet, and is dried.
Even when the superposed surfaces are brought into contact with each other, an adhesive portion that does not adhere in a normal state (high blocking resistance) can be formed,
Even if a release material such as silicone oil is transferred and adhered from a printing machine or a printer to the surface of the bonded portion, the fine particulate filler in the bonded portion absorbs oil and is not adversely affected by silicone oil or the like. By applying a predetermined pressure by bringing the superposed surfaces into contact with each other, a remarkable effect that the superposed surfaces can be firmly and completely adhered to each other is exerted.

The pressure-sensitive adhesive composition according to the second aspect of the present invention has the same effects as the pressure-sensitive adhesive composition according to the first aspect, and also has the effects of being more excellent in blocking resistance and oil absorption. Play.

The pressure-sensitive adhesive sheet according to the third aspect of the present invention has an adhesive portion that does not adhere in a normal state even when the overlapping surfaces are brought into contact with each other. By applying the pressure, it is possible to obtain an effect that the overlapping surfaces can be firmly bonded to each other. For example, when an envelope is formed by firmly bonding predetermined ends of an envelope upper paper and an envelope lower paper, or a concealed label. Such a method can be used for firmly bonding such as to a target object, or for firmly bonding predetermined ends of each sheet of carbonless paper composed of a plurality of sheets.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a pressure-sensitive adhesive sheet of the present invention.

FIG. 2 is an explanatory view showing the pressure-sensitive adhesive sheet of the present invention in FIG. 1 in a cross section along the longitudinal direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Continuous envelope 2 Continuous envelope upper paper 3 Continuous envelope lower paper (pressure-sensitive adhesive sheet of the present invention) 4 Paper transport hole 5 Information printing section 6 Unit envelope upper paper 7 Separation section 8 Unit envelope lower paper 9 Envelope 10 Adhesive section

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09J 125/08 C09J 125/08 F term (Reference) 4J004 AA05 AA06 AA10 AB01 4J040 BA102 CA082 DB032 DB062 DF051 DL031 HA306 JB09 KA42

Claims (3)

[Claims] An adhesive portion which is applied to a superimposed surface of a sheet and which does not adhere in a normal state by a drying process is formed, and the superimposed surfaces are brought into contact with each other and a predetermined pressure is applied thereto, whereby the superimposed surface is formed. A pressure-sensitive adhesive for firmly adhering each other, wherein a styrene-rich SBR latex and / or a polystyrene emulsion having a styrene content of 70 to 95% is added to 100 parts by mass of a methyl methacrylate graft copolymerized natural rubber-based pressure-sensitive adhesive solid content. And / or adhesive base 10 containing styrene / acrylic copolymer emulsion so that its solid content is 5 to 50 parts by mass.
The oil-absorbing fine-grained filler and the spherical fine-grained filler having incompatibility with the adhesive base are each in the range of 10 to 40 parts by mass, and the total amount of both is 2 to 0 parts by mass.
A pressure-sensitive adhesive composition, which is blended so as to be 0 to 60 parts by mass. 2. The oil-absorbing fine-particle filler has an average particle size of 1 to 10
2. The pressure-sensitive adhesive composition according to claim 1, wherein the pressure-sensitive adhesive composition is silica gel having a particle size of μm, and the spherical fine-particle filler is starch having an average particle size of 10 to 20 μm. 3. A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive composition according to claim 1 on a predetermined portion of a superposed surface of a base sheet.