JPH05171119A - Production tacky sheet - Google Patents

Abstract

PURPOSE:To eliminate problems resulting from cutting of substrate during a drying process and to obtain a tacky sheet not causing curling or a tacky sheet utilizing a specific substrate by a specific method not using a surface substrate or a release substrate in a drying process of tacky agent. CONSTITUTION:First, an endless member 1a subjected to surface release treatment is coated with a coating compound 2 of tacky agent by a coater 3 and dried by a dryer 4a to form a tacky agent layer 5. Then, the tacky agent layer 5 on the endless member 1a is bonded to a surface substrate 7 under pressure by nip rolls 8, the tacky agent layer 5 is transferred to the surface substrate 7 and a release substrate 10 is stuck to the surface of the tacky agent layer 5 by nip rolls 11 to give a tacky sheet 12. A die coater is preferable as the coater. A hot-air dryer is preferable as the dryer. Fluororesin processing is preferable as the release treatment of the endless member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a pressure-sensitive adhesive sheet, and more particularly to a method for producing a pressure-sensitive adhesive sheet which transfers a pressure-sensitive adhesive layer onto a surface substrate.

[0002]

2. Description of the Related Art A pressure-sensitive adhesive sheet is a laminate of a surface base material, an adhesive, and a release base material, and is used in various fields as product labels, price labels, address labels, name plates, stickers, stickers, patches, delivery slips, etc. It is used.

Generally, a method for producing a pressure-sensitive adhesive sheet is a method in which a pressure-sensitive adhesive is applied to a surface base material and dried, and then a release base material is bonded, or conversely, a pressure-sensitive adhesive is applied to the release base material and dried. A method of laminating and transferring a surface base material is performed.

As the coating apparatus used in these methods, for example, coating apparatuses such as various roll coaters, knife coaters, bar coaters and die coaters are used. And, as for the drying method, except for special examples such as hot-melt adhesives and ultraviolet-curing adhesives, a drying device using heat is mostly used.

However, in the above-mentioned conventional method, when the substrate is cut by the drying device during the operation, the inside of the device becomes dirty, which is a serious problem.

When an adhesive coating is applied to a surface base material or a release base material while leaving uncoated portions such as ears (dry edge) and partial coating (part coat), it is necessary to apply the base material during drying by heat. A difference in water content and a difference in expansion and contraction between the coated portion and the uncoated portion of the material may cause wrinkles and curls in the base material, or cutting due to cutting of the edges may cause a problem.

Furthermore, when a pressure-sensitive adhesive coating is applied to a surface base material or a release base material and dried by heat, the water content of the base material also evaporates to some extent, resulting in excessive dryness of the base material, which causes various problems in a drying device. Cause operational troubles. The base material that has become excessively dried, as a product of the pressure-sensitive adhesive sheet, causes curling during the printing process or final use, which causes a problem.

As a method for reducing the above-mentioned excessive drying,
For example, the temperature of drying by heat is also set to a low temperature, but it is necessary to reduce the operating speed or install a drying process of a length corresponding to the drying time for high speed operation. is there.

In the recent market of pressure-sensitive adhesive sheets, the number of types of paper has increased, and the applications have come to be used in a very wide range. In addition, many attempts have been made to open up new markets by using foils, films, non-woven fabrics other than paper, or composite materials of these as surface substrates and release substrates.

Some of the base materials of these new products cannot be heated to a high temperature, and some of them are not suitable for the adhesive processing. In addition, copying machines, printers, etc. require special use conditions, which causes curling during final use, which is a problem and cannot meet the conventional quality goals, requiring extremely high non-curl quality. ing.

[0011]

The object of the present invention is to prevent the use of a surface base material or a release base material for the adhesive drying step, thereby eliminating the problem of cutting the base material in the drying step and preventing curling. The present invention provides a method for producing a pressure-sensitive adhesive sheet and a method for producing a pressure-sensitive adhesive sheet suitable for developing a new pressure-sensitive adhesive sheet using a special surface substrate or release substrate.

[0012]

The present invention is a method for producing a pressure-sensitive adhesive sheet which basically comprises a surface base material, an adhesive layer, and a release base material. After applying the adhesive paint with a coating device and drying it with a drying device to form an adhesive layer, press the adhesive layer on the endless member and the surface base material with a nip roll to transfer the adhesive layer to the surface base material. And a release base material is then attached to the surface of the adhesive layer.

[0013]

The method for producing a pressure-sensitive adhesive sheet of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic side view of an example in which the endless member is an endless sheet for explaining the entire method for producing a pressure-sensitive adhesive sheet of the present invention, and FIG. 2 leaves an uncoated portion in the gap between the coating device and the endless member. FIG. 3 is an explanatory view in which a thin plate is provided, and FIG. 3 is a schematic side view for explaining the entire example of the endless member being a large diameter drum roll. The coating device is shown as an example of a die coater.

In FIG. 1, an endless sheet 1a, which is an endless member whose surface is subjected to a peeling process, is continuously run, and an adhesive paint 2 is applied on the surface by a coating device die coater 3 in accordance with a target width. To do. The applied pressure sensitive adhesive paint is dried by the hot air drying device 4a to form the pressure sensitive adhesive layer 5. On the other hand, the back surface of the surface base material 7 fed from the first unwinding stand 6 is pressure-bonded to the surface of the adhesive layer by the first nip roll 8, and the adhesive layer is released from the surface of the endless sheet to form a surface. It is transferred to the substrate. Further, the peeling base material 10 fed from the second unwinding stand 9 is bonded by the second nip roll 11 so that the peeling treated surface is pressure-bonded to the adhesive layer. The pressure-sensitive adhesive sheet 12 thus laminated is the winding stand 1
It is rolled up to 3.

The coating apparatus is preferably the die coater exemplified above, but is not limited thereto. For example, various roll coaters, gravure coaters, knife coaters, bar coaters, blade coaters and the like can be used. ..

As the drying device, a general device is used, but as a method for applying heat, a method mainly using hot air is preferably used. Hot air is obtained by exchanging heat from heat sources such as steam, gas, and electricity. Set the hot air temperature, wind speed, air volume, circulation, etc. according to the purpose. Further, a heating method such as direct heating by electric heat, direct heating by infrared rays, direct heating by ultraviolet rays, direct heating by gas combustion flame, direct heating by dielectric heating, direct heating by heating, and heating on the surface of the drum or roll by heating the surface of the drum or roll can be used. Further, a method of heating them in combination is also preferable.

FIG. 2 shows a method in which a thin plate is provided in the gap between the coating device and the endless member to completely eliminate coating other than the coating purpose. When the adhesive coating liquid is applied to the endless member, if a coating part wider than the width of the surface base material is formed, the adhesive layer that is not transferred to the surface base material remains on the endless member and stains the nip roll, or It will not be possible to transfer the adhesive coating liquid to a portion wider than the target width because it may cause problems such as returning to the coating device with the adhesive attached. This prevents the loss of the adhesive coating liquid and reduces the maintenance of stains in the entire process. Further, a method for manufacturing a dry edge having an uncoated portion in the ear portion and a part coat having a partially coated portion will be described. That is, the thin plate 14 is provided in the gap between the endless sheet 1a and the coating device 3 shown in FIG. 2 according to the target coating width. Since this thin plate can prevent transfer of the adhesive paint, the thin plate part becomes an uncoated part. The width of the uncoated part can be freely selected depending on the width of the thin plate. Also, the number of thin plates may be selected according to the target, and the thin plate thickness is selected according to the size of the gap and the coating liquid amount. As the material of the thin plate, for example, metal, synthetic resin, paper, cloth or the like is used, and various synthetic resin films are particularly preferably used.

As specific examples of the endless member used in the present invention, various endless belts, endless sheets, drum rolls and the like can be used. The structure of the endless sheet is not particularly limited, but, for example, a belt made of metal or rubber or a base cloth of heat resistant fiber to which a heat resistant synthetic resin is adhered or applied is used. Also, if it has sufficient strength, it may be composed of only synthetic resin,
In some cases, paper and various laminated materials are used.

FIG. 3 shows an example of using a drum roll as the endless member. Large diameter drum roll 1
The pressure-sensitive adhesive paint 2 is applied to the surface of b by a coating device die coater 3 according to the target and dried by a drying device 4b to form a pressure-sensitive adhesive layer 5. On the other hand, the back surface of the surface base material 7 fed from the first unwinding stand 6 is pressure-bonded onto the adhesive layer by the first nip roll 8, and the adhesive layer is released from the large-diameter drum roll to form the surface. It is transferred to the substrate. The operation of the subsequent steps is the same as in the case of the endless sheet. The diameter of the drum roll should be as required for the dry length. When the adhesive layer is extremely small, a large drum roll is not required, so a small diameter is possible.

As a method for subjecting the surface of the endless member to a peeling treatment, various treatment methods generally used can be applied, but among them, those treated by a fluororesin treatment are preferably used. For the fluororesin processing, for example, a coating film of FEP (fluoroethylene propylene) alone or a coating film of FEP mixed with other various polymer components for the purpose of improving compressive stress is preferably used. The thickness of the release coating film is adjusted within the range of 10 to 60 μm.

The surface smoothness of the peeled endless member is preferably as smooth as the surface roughness appears directly on the surface of the pressure-sensitive adhesive layer, and it is particularly preferable that the surface is polished to 25 μm or less, more preferably 10 μm or less. However, in order to obtain a specific adhesive layer, it is good to have a mirror surface of 2 μm or less. Further, when the endless sheet has a uniform thickness, the coating liquid layer applied by the coating device can be made uniform. Then, the drum roll can improve the accuracy of the circle and make the gap between the drum roll and the coating device uniform, so that an extremely uniform adhesive layer can be obtained. Obtaining these smooth and uniform pressure-sensitive adhesive layers is an effect of the present invention that cannot be obtained by a production method using a release substrate as a process paper.

In the method for producing a pressure-sensitive adhesive sheet of the present invention, since the endless member has sufficient strength, there is no fear of cutting during drying, and the endless member does not curl, so that the problem of soiling the inside of the drying device is solved. You can

In the dry edge having the uncoated portion at the ears and the part coat having the coated portion as a part, the difference in water content and the difference in expansion and contraction due to the drying of the base material to be the adhesive sheet causes cutting and quality during the process. However, since the substrate is not dried by the method of the present invention, there is no need to worry about this problem. Similarly, there is no problem of overdrying of the base material, and since the base material whose water content is adjusted to the normal humidity range becomes the pressure-sensitive adhesive sheet as it is, there is an effect of raising the curl quality standard.

In the present invention, it is preferable that at least one of the nip rolls is an elastic roll and each of the first and second nip is provided. The elastic material of the elastic roll is appropriately selected and used from commonly used materials such as synthetic resin, rubber and fiber. The hardness of the elastic roll is adjusted to have a Shore D hardness (ASTM standard D-2240) of 50 to 90 degrees, more preferably 60 to 80 degrees. A soft roll of less than 50 degrees requires an excessive nip linear pressure to obtain sufficient pressure bonding, while a hard roll of more than 90 degrees does not function as a cushion and it is difficult to prevent wrinkles.

The nip line pressure is appropriately adjusted according to various conditions, but is preferably in the range of 30 to 150 kg / cm. It is difficult to reliably transfer the adhesive layer with a weak linear pressure of less than 30 kg / cm, and an excessively strong linear pressure of more than 150 kg / cm may deform the adhesive layer. However, in the case where the second nip roll, which comes into contact with the surface base material, is made into a hard roll having a good surface smoothness to smooth the surface of the pressure-sensitive adhesive sheet, a linear pressure as high as possible close to 150 kg / cm is effective.

Further, it is preferable to adjust the surface temperature of the roll by passing a refrigerant through the roll of the nip roll.

Further, it is preferable to install a device for cooling the endless member and the adhesive layer between the drying device by heating and the nip roll so that the temperature entering the nip roll is as close to room temperature as possible. By this, for example, a base material whose temperature is important, such as a heat-sensitive color-developing sheet, can be used as an adhesive sheet without any problem. The closer the temperature of the adhesive layer is to room temperature, the better the curling characteristics of all adhesive sheets in many cases.
Of course, when the curl characteristics are corrected by utilizing the high temperature, or when the good curl characteristics are obtained by the high temperature, it is preferable to effectively use the temperature after drying or to use a device that gives the temperature.

In the method of the present invention, when pressure is applied by the first and second nip rolls, the tension control of the substrate fed from the unwinding stand is preferably 0.20 Kg / cm or less so that the tension is as low as possible for curling. The result is obtained. By the way, tension exceeding 0.20 kg / cm is due to expansion and contraction and internal stress due to the tension of the substrate,
It tends to cause curling of the pressure-sensitive adhesive sheet.

As the surface base material and the release base material, any of paper, synthetic paper, film, foil, composite structure and laminated structure can be used. In particular, in the case of a base material including a heat-sensitive color-developing sheet, special paper, special sheet, etc. or paper having poor heat resistance, synthetic paper, film, etc., which is particularly affected by heat, the production method of the present invention is extremely It is valid. Further, it is also effective for a very thin base material used in, for example, a copying machine or a printer, or a base material having a relatively weak strength.

The pressure-sensitive adhesive has various forms and quality characteristics such as water-based, oil-based, non-volatile, UV-curable and the like, and quality characteristics such as permanent adhesion, strong adhesion, medium adhesion, light adhesion, and re-peeling. It is not particularly limited.

[0031]

The present invention will be described in more detail with reference to the following examples, but of course the present invention is not limited thereto.

Example 1 An endless sheet obtained by exfoliating stainless steel with a fluororesin FEP and a coating part having a width larger than the width of the surface substrate were not formed,
A pressure-sensitive adhesive sheet was manufactured using the apparatus of FIG. 1 in which a coating apparatus die coater provided with a thin plate having both edges as dry edges was installed. An elastic roll having a roll hardness Shore D of 70 degrees was used for the side of the first and second nip rolls that was in contact with the surface substrate, and the linear pressure was adjusted within the range of 50 to 100 Kg / cm.
The tension of the surface base material and the release base material at the entrance and exit of the nip roll was 0.1 to 0.18 Kg / cm.

Acrylic emulsion type pressure-sensitive adhesive as a pressure-sensitive adhesive coating was applied to the surface of the endless sheet so that the dry weight was 20 g / m ² , dried with hot air, cooled and adjusted to about 40 ° C. A thermosensitive coloring film was used as a material to transfer the adhesive layer to the back surface of the front surface base material with a first nip roll, and then glassine release paper was used as a release base material to bond the release treated surface to the adhesive layer with a second nip roll. In this step, there was no stain on the area beyond the width of the surface of the endless sheet, and the operation could be performed without any problems. The thermosensitive color developing film pressure-sensitive adhesive sheet thus obtained was flat and no curl was observed in a room at room temperature and normal humidity. Further, the sheet feeding suitability of the thermal printer was good.

Example 2 In Example 1, thin plates having a width of 20 mm were provided at intervals of 150 mm and applied to a part coat, and a lower paper of pressure-sensitive coloring paper was used as a surface base material and a fine release paper was used as a release base material. A multi-layered combination adhesive sheet for delivery slips was produced in the same manner as in Example 1 except that it was used. There were no problems during operation,
This adhesive sheet did not show any blister or curl in the uncoated part of the part coat. Also, the suitability for printing forms for delivery slips was good.

Example 3 Similar to Example 1 except that as the surface substrate, a high-quality paper having a basis weight of 40 g / m ² was used, and as a release substrate, a high-quality release paper having a basis weight of 45 g / m ² was used. Then, an adhesive sheet for an electrophotographic copying machine was manufactured. There was no problem during operation, this adhesive sheet was flat indoors, and it was set in a Xerox copier and copied, but there was no trouble such as jamming and it could be used without problems.

Example 4 The surface of an endless sheet obtained by applying a heat-resistant synthetic resin polyester resin to a heat-resistant base fabric using nylon fiber was subjected to a peeling treatment using a fluororesin FEP, and the surface roughness was about 5 μm. The endless sheet was polished to obtain the endless sheet used in the present invention. Other than that was the same as that of Example 1. No problem was observed during the operation, and the obtained heat-sensitive color developing film pressure-sensitive adhesive sheet was flat and no curl was observed in a general room at room temperature and normal humidity as in Example 1. Further, the sheet feeding suitability of the thermal printer was good.

Example 5 A synthetic paper pressure-sensitive adhesive sheet was produced in the same manner as in Example 4 except that synthetic paper was used as the surface base material and single-sided polyethylene laminate release paper was used as the release base material.
No problem was observed during operation, and the obtained synthetic paper pressure-sensitive adhesive sheet was completely flat and had no curl in a room at normal temperature and normal humidity. Moreover, the label was prepared by removing the residue by sticker printing, and the label was attached to the product by the auto labeler, but the suitability for end use was also good.

Example 6 On the surface of a large diameter drum roll having a diameter of 3 m, fluororesin FE was used.
A peeling treatment was carried out using P, and polishing was performed so that the surface roughness became about 2 μm, and the device of FIG. 3 was obtained. Adhesive sheet with a coating device die coater installed in the gap between the surface of the large-diameter drum roll and the coating device. Was manufactured. An elastic roll having a roll hardness Shore D of 70 degrees was used for the side of the first nip roll that was in contact with the surface substrate, and the linear pressure was 50.
Adjusted in the range of 100 Kg / cm, the side of the second nip roll that comes into contact with the surface base material is a metal roll with good smoothness, and the side that comes into contact with the release base material is an elastic roll with a Shore hardness of D70 degrees, and the linear pressure is 50 to It was adjusted in the range of 150 Kg / cm. The tension of the surface base material and the release base material at the entrance and exit of the nip roll is 0.1 to 0.18 Kg / cm.
Met.

An acrylic emulsion type pressure sensitive adhesive was applied as a pressure sensitive adhesive coating on the surface of a large diameter drum roll so that the dry weight was 22 g / m ² , dried with hot air, and then cast coated paper was used as the surface base material. The pressure-sensitive adhesive layer was transferred to the surface base material by the first nip roll, and subsequently, the single-sided poly-laminate release paper as the release base material was attached to the pressure-sensitive adhesive layer by the second nip roll. In this step, there was no stain on the area larger than the width of the surface substrate of the large diameter drum roll, and the operation could be performed without any problem. The cast coated paper pressure-sensitive adhesive sheet thus obtained was completely flat and no curl was observed in a room at room temperature and normal humidity.
Further, the appearance smoothness of the surface of the cast coated paper of the pressure-sensitive adhesive sheet was extremely good.

[0040]

As is apparent from the results of the examples, according to the method for producing a pressure-sensitive adhesive sheet of the present invention, the endless member is not cut by the drying device in the production process and the width of the surface base material of the endless member is not less than Since there is no transfer of the coating liquid to a part, the pressure-sensitive adhesive sheet having excellent curl characteristics can be produced without contaminating the inside of the drying device or the subsequent steps. Furthermore, the pressure-sensitive adhesive sheet can be produced without any problem even if a surface base material or a release base material which is problematic when affected by heat temperature is used. Also, an adhesive sheet using thin paper can be manufactured without any problem. Further, a uniform pressure-sensitive adhesive layer can be obtained, and the surface smoothness of the surface base material of the pressure-sensitive adhesive sheet can be manufactured extremely well by utilizing the nip roll.

[Brief description of drawings]

FIG. 1 is an explanatory view of an example in which an endless sheet is used as an endless member for explaining the whole method for producing a pressure-sensitive adhesive sheet of the present invention.

FIG. 2 is an explanatory diagram of an example in which a thin plate for leaving an uncoated portion is provided in a gap between a coating device and an endless member in the method for producing a pressure-sensitive adhesive sheet according to the present invention.

FIG. 3 is an explanatory view showing an example of an embodiment of the method of the present invention using a large diameter drum roll as an endless member.

[Explanation of symbols]

 1a Endless sheet 1b Large diameter drum roll 2 Adhesive paint 3 Die coater as an example of coating device 4a Hot air drying device 4b Hot air drying device 5 Adhesive layer 6 First unwinding stand 7 Surface substrate 8 First nip roll 9 Second roll Output stand 10 Release base material 11 Second nip roll 12 Adhesive sheet 13 Winding stand 14 Thin plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuhiro Takeda 4-3-1 Jōkoji, Amagasaki City, Hyogo Prefecture Kanzaki Paper Manufacturing Co., Ltd. Kanzaki Mill

Claims (6)

[Claims] 1. A method for producing a pressure-sensitive adhesive sheet basically composed of a surface substrate, a pressure-sensitive adhesive layer, and a peeling substrate, wherein a pressure-sensitive adhesive paint is coated on an endless member whose surface has been subjected to a peeling treatment. After coating and drying with a drying device to form a pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer on the endless member and the surface substrate are pressure-bonded with a nip roll to transfer the pressure-sensitive adhesive layer to the surface substrate, and then on the surface of the pressure-sensitive adhesive layer. A method for producing a pressure-sensitive adhesive sheet, which comprises laminating a release base material. 2. The method for producing an adhesive sheet according to claim 1, wherein a thin plate for leaving an uncoated portion is provided in a gap between the coating device and the endless member. 3. The method for producing an adhesive sheet according to claim 1, wherein the peeling treatment on the surface of the endless member is a fluororesin processing. 4. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein at least one of the nip rolls is an elastic roll, and the roll hardness is a Shore D hardness of 50 to 90 degrees. 5. The method for producing an adhesive sheet according to claim 1, wherein the endless member is an endless sheet. 6. The method for producing an adhesive sheet according to claim 1, wherein the endless member is a drum roll.