JP2002188063A - Method for producing tacky sheet and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a tacky sheet having good appearance, by which occurrence of foam in a tacky agent is suppressed and apparatus therefor. SOLUTION: This method for producing the tacky sheet comprises heat-drying a tacky agent composition applied on the surface of a substrate and removing a solvent from the tacky agent composition to provide a tacky agent layer. The method for producing the tacky sheet is characterized by including a defoaming step for defoaming the tacky agent composition by applying the tacky agent composition onto the surface of the substrate and keeping the applied tacky agent composition in unheated state and a step for providing the tacky agent layer by heating and drying the composition and removing the solvent from the tacky agent composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for producing a pressure-sensitive adhesive sheet having good appearance.

[0002]

2. Description of the Related Art Conventionally, in the production of an adhesive sheet, an adhesive polymer, a tackifying resin, and other additives are dissolved in an organic solvent such as toluene or ethyl acetate, or emulsified in water using an appropriate emulsifier. A pressure-sensitive adhesive composition is applied on the surface of a support, and then heated and dried by hot air or infrared rays.

[0003] However, the pressure-sensitive adhesive composition is agitated in the preparation stage and contains many bubbles. In addition, the pressure-sensitive adhesive composition needs a certain viscosity so that it does not flow when applied to the support, so that bubbles contained at one end are not easily removed. When the pressure-sensitive adhesive composition is applied to the support while containing the bubbles, the bubbles remain in the pressure-sensitive adhesive layer, and the bubbles expand in a subsequent drying step. As a result, the dried pressure-sensitive adhesive layer has a thickness of several hundred μm to There are many bubbles of several mm. The bubbles generated in the pressure-sensitive adhesive layer remain as bubbles inside the pressure-sensitive adhesive layer, or a part thereof projects to the outside to form a convex portion on the surface of the pressure-sensitive adhesive layer. A recess is formed on the surface. As a result, the pressure-sensitive adhesive layer becomes non-uniform and the transparency is reduced, and the surface of the pressure-sensitive adhesive layer becomes poor in smoothness, which adversely affects the appearance and properties. This phenomenon was particularly remarkable in an aqueous pressure-sensitive adhesive composition.

In order to solve this problem, Japanese Patent Publication No. 2-12
No. 121 and Japanese Patent Application Laid-Open No. 7-144104 disclose a method for removing bubbles in a liquid by a continuous vacuum degassing apparatus. However, in these methods, air bubbles can be once removed before coating, but in the actual manufacturing process, air bubbles are entrained again in the liquid reservoir of the coating portion or in the bank portion to be transferred to the substrate, and as a result, Has a problem that the pressure-sensitive adhesive layer is formed while air bubbles are involved.

Further, in the defoaming operation by the above-mentioned reduced pressure, a phenomenon called so-called skinning, in which a liquid surface is dried to form a continuous film, is likely to occur, which makes it difficult to continuously perform mechanical treatment. ing.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and provides a method and an apparatus for producing a pressure-sensitive adhesive sheet which reduces bubbles generated when producing the pressure-sensitive adhesive sheet. With the goal.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, after applying the pressure-sensitive adhesive composition on the surface of a support, the coated pressure-sensitive adhesive composition Defoaming the pressure-sensitive adhesive composition by keeping it in a non-heated state, and then heating and drying to remove the solvent from the pressure-sensitive adhesive composition to form a pressure-sensitive adhesive layer, thereby preventing the generation of bubbles in the pressure-sensitive adhesive layer They have found that they can do this and have completed the present invention.

[0008] That is, the present invention provides a method for producing a pressure-sensitive adhesive sheet for forming a pressure-sensitive adhesive layer by removing the solvent from the pressure-sensitive adhesive composition by heating and drying the pressure-sensitive adhesive composition applied on the surface of the support. In the step of applying the pressure-sensitive adhesive composition on the surface of the support, a step of defoaming the pressure-sensitive adhesive composition by keeping the applied pressure-sensitive adhesive composition in a non-heated state, and then heating and drying the pressure-sensitive adhesive The present invention relates to a method for producing a pressure-sensitive adhesive sheet, which comprises a step of removing a solvent from a composition to form a pressure-sensitive adhesive layer (claim 1), and in particular, coating the pressure-sensitive adhesive composition on a surface of a support. After heating, the non-
The present invention relates to a method for producing a pressure-sensitive adhesive sheet, wherein the pressure-sensitive adhesive composition is maintained for 0 second (claim 2), and the pressure-sensitive adhesive composition is a water-based pressure-sensitive adhesive composition. Item 3).

[0009] The present invention also relates to an adhesive for producing an adhesive sheet for forming an adhesive layer by removing the solvent from the adhesive composition by heating and drying the adhesive composition applied on the surface of the support. In the sheet manufacturing apparatus, a coating section for applying a pressure-sensitive adhesive composition on the surface of the support, a drying section for removing a solvent from the applied pressure-sensitive adhesive composition by heating, the coating section and the drying section An apparatus for producing an adhesive tape, comprising a non-heating section for maintaining a non-heating state between the sections.
It is related to.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. <First Embodiment> A schematic structure of a pressure-sensitive adhesive sheet manufacturing apparatus according to the present embodiment will be described with reference to FIG. FIG. 1 is a longitudinal sectional view showing a schematic configuration of a pressure-sensitive adhesive sheet manufacturing apparatus according to an embodiment of the present invention.

The apparatus for manufacturing a pressure-sensitive adhesive sheet according to the present embodiment comprises:
As shown in FIG. 1, roughly divided into a support supply roll 2 on which a support 1 such as a sheet, a tape, or a film is wound, and a support 1 from the support supply roll 2. A coating section 3 for applying (applying) the pressure-sensitive adhesive composition to a desired thickness; a non-heating section 4 for maintaining the pressure-sensitive adhesive composition applied to the support 1 in a non-heated state; A drying unit 5 for heating the coated pressure-sensitive adhesive composition to remove a solvent from the pressure-sensitive adhesive composition to form a pressure-sensitive adhesive layer;
And a winding unit 6 that winds the support 1 that has been dried by heating. Hereinafter, the configuration of each unit will be described in detail.

The support supply roll 2 is wound around a support (substrate) 1 such as a sheet, a tape, or a film.

The coating unit 3 applies the pressure-sensitive adhesive composition to the support 1 from the support supply roll 2 so as to have a desired width and a desired thickness in the width direction of the support 1. It is for. The coating unit 3 adheres, for example, a liquid supply layer 31 for supplying the pressure-sensitive adhesive composition to the surface of the pressure-sensitive adhesive composition supplied from the liquid supply layer 31 according to a desired width of the support 1. A coating roll 32 for controlling the thickness of the pressure-sensitive adhesive composition attached to the coating roll 32 together with the coating roll 32, and the support 1 in close contact with the coating roll 32. And a backup roll 34 for transporting the paper. In this way, the pressure-sensitive adhesive composition is applied to the support 1 so that the support 1 has a desired width and a desired thickness.

The structure of the coating unit 3 is not limited to the reverse coater as described above, but may be another coating method such as a gravure coater. The method of adjustment can be appropriately changed and implemented in accordance with each coating method.

The non-heating section 4 is provided for maintaining the non-heating state until the pressure-sensitive adhesive composition applied to the support 1 enters the drying section 5. The configuration of the non-heated section 4 is not particularly limited as long as the support 1 coated with the pressure-sensitive adhesive composition can be kept in a non-heated state, as long as the support 1 is smoothly transported. Here, the non-heated state refers to a state in which the ambient temperature is maintained at about the same level as room temperature, and preferably refers to a state in which the temperature is adjusted to within room temperature + 10 ° C. By keeping the pressure-sensitive adhesive composition at around room temperature, the solvent is not volatilized at once, but the bubbles entrained in the pressure-sensitive adhesive layer are released from the surface of the pressure-sensitive adhesive layer, and the defoaming effect is obtained. Therefore, if necessary, the temperature can be adjusted by an air conditioner.

The non-heating section 4 is preferably provided with an enclosure so that dust and dirt from outside do not adhere to the surface of the adhesive layer. Further, an exhaust system can be provided to remove the volatile solvent.

The time for keeping the non-heated state is not particularly limited as long as the applied pressure-sensitive adhesive composition is defoamed, and is appropriately determined depending on the type, viscosity, thickness, etc. of the pressure-sensitive adhesive composition. . In a commonly used apparatus for manufacturing a pressure-sensitive adhesive sheet, an idle section of about 10 seconds is required between the coating section 3 and the drying section 5, but in this time, the effect of defoaming the pressure-sensitive adhesive composition is obtained. No, it does not correspond to the non-heating portion referred to in the present invention. In order to achieve the object of the present invention, usually the non-heated state is 5
It is preferable to keep it for 0 seconds or more, and if it is less than 50 seconds, a sufficient defoaming effect may not be obtained. On the other hand, by taking a long time to keep the non-heated state, this effect becomes more remarkable, but the space problem described later, and when the pressure-sensitive adhesive composition is applied thickly, uneven thickness or defective portions may occur. Yes, preferably within 400 seconds.

Therefore, the length of the non-heated portion 4 is determined according to the time for maintaining the non-heated state and the coating speed. [Seconds]
The length L [m] of the non-heating portion 4 required to secure the time for maintaining the non-heating state is L = V × (T / 60) or more.

In the present invention, the drying section 5 heats the pressure-sensitive adhesive composition applied to the support 1 to remove a solvent and unreacted monomers from the pressure-sensitive adhesive composition to form a pressure-sensitive adhesive layer. The configuration is not particularly limited, but a floating system in which hot air is blown from above and below the substrate is preferably used.

In the present invention, an infrared heater can be used in the drying step. The infrared radiation energy promotes drying from the inside of the pressure-sensitive adhesive solution layer, facilitates diffusion of water in the pressure-sensitive adhesive layer during drying,
Bubbles generated in the pressure-sensitive adhesive layer can be reduced, and there is also an effect of shortening the drying time.

Although the infrared heater used in the present invention is not particularly limited, a far-infrared heater in which a resistance heating element is arranged near a plate-like or cylindrical ceramic material having a high emissivity is used. preferable. The conditions for use can be appropriately determined as long as the effects of the present invention are not hindered.

The winding section 6 includes a guide roller 61 for guiding the support 1 dried in the drying section 5 in a predetermined direction, and a dried support 1 guided by the guide roller 61. And a support take-up roll 62 for take-up.

Next, the manufacturing process for manufacturing the pressure-sensitive adhesive sheet by the embodiment apparatus constructed as described above will be described below.

First, a support 1 in the form of a sheet, tape, or film is wound on a support supply roll 2. In the present invention, the support 1 is not particularly limited, and for example, papers (Japanese paper, kraft paper, etc.), cloths (cotton, soft cloth, synthetic fiber, nonwoven fabric, etc.), plastics (cellophane, polypropylene, ethylene) -Propylene copolymer, polyester, polyethylene, polyvinyl chloride, acetate, polystyrene, polyacrylonitrile, etc.), metal foil, or a plastic laminate of these can be used. Its thickness is usually 10 ~
Although it is about 300 μm, it can be appropriately determined according to the type, use, and purpose of the base material used. Further, a substrate which has been subjected to a known treatment such as an undercoating treatment, a filling treatment, a corona treatment, and a back surface treatment can be used for the substrate.

Next, the pressure-sensitive adhesive composition is applied to the support 1 supplied from the support supply roll 2 by the coating unit 3 so as to have a desired width and a desired thickness of the support 1. This is a coating process for coating.

In the present invention, as the pressure-sensitive adhesive composition,
An acrylic, natural rubber-based, synthetic rubber-based, or mixture thereof-based adhesive may be appropriately dissolved in a solvent such as toluene or ethyl acetate. In addition, those obtained by dispersing these adhesives in water using an emulsifier or a dispersant can be used. In the present invention, particularly when a water-based pressure-sensitive adhesive composition is used, since the surfactant acts as a foaming agent, bubbles are easily generated, and the production method of the present invention is particularly effective.

The acrylic pressure-sensitive adhesive is used for the purpose of improving the adhesion of the pressure-sensitive adhesive layer to the support and the initial adhesion to the adherend to the (meth) acrylic acid ester which is the main monomer. A polymer obtained by using a functional group-containing vinyl monomer in combination with an appropriate polymerization initiator or the like can be used. In particular, in the case of a water-based pressure-sensitive adhesive, an emulsifier and a dispersant can be appropriately used in combination.

As the (meth) acrylate, a wide variety of monomers or monomer mixtures can be used. For example, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acryl Propyl acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, ( Neopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate , Isodecyl (meth) acrylate, lauryl (meth) acrylate, bornyl (meth) acrylate Isobornyl (meth) acrylate, (meth) acrylate, myristyl (meth) acrylate, pentadecyl and stearyl (meth) acrylate.

These (meth) acrylates are:
It is preferred to use from 60 to 99% by weight of the total monomer mixture. If it is less than 60% by weight, the adhesive properties may be impaired.

The amount of the functional group-containing vinyl monomer can be appropriately selected depending on the type of each monomer within a range of 40% by weight or less of the total monomer mixture, but good pressure-sensitive adhesiveness is exhibited. In order to achieve this, it is desirable to determine the amount to be used so that the glass transition point of the obtained polymer is usually −20 ° C. or lower.

Examples of the vinyl monomer having a functional group copolymerizable with the (meth) acrylic acid ester include acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, crotonic acid, maleic acid, fumaric acid, (meth) Hydroxyalkyl acrylate, glycerin dimethacrylate, glycidyl (meth) acrylate, methyl glycidyl methacrylate, aminoethyl (meth) acrylate, 2-
Functional monomers such as methacryloyloxyethyl isocyanate, triethylene glycol diacrylate,
Polyfunctional monomers such as ethylene glycol dimethacrylate and trimethylolpropane tri (meth) acrylate, vinyl acetate, styrene, (meth) acrylonitrile, N-vinylpyrrolidone, (meth) acryloylmorpholine, cyclohexylmaleimide, isopropylmaleimide, (meth) Acrylamide and the like can be mentioned.

As the emulsifier used in the present invention, generally used anionic or nonionic emulsifiers can be used. Examples of the anionic type include sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkylphenyl ether sulfate, sodium polyoxyethylene alkyl sulfosuccinate, and the like. Further, for example, a radical polymerizable emulsifier into which a propenyl group or the like is introduced may be used.

Examples of the nonionic emulsifier include polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene polyoxypropylene block polymer. These anionic or nonionic emulsifiers include Depending on the type of monomer, one or more kinds can be used.

In the present invention, the emulsifier is used in an amount of 0.1 to 5 parts by weight, preferably 0.4 to 3 parts by weight, based on 100 parts by weight of the monomer mixture.
By limiting the amount of the emulsifier to the above value or less, a water-dispersed pressure-sensitive adhesive excellent in water resistance and adhesive properties can be obtained.

The polymer particle size of the aqueous pressure-sensitive adhesive produced by emulsion polymerization using the above-mentioned emulsifier may be 0.1 to 3 μm as long as it has good mechanical stability and coatability.
m, preferably 0.2 to 1 μm. Here, when the particle size is smaller than 0.1 μm, the viscosity of the water-dispersed pressure-sensitive adhesive increases, and when the particle size is larger than 3 μm, the fusion property between the particles may decrease and the cohesive force may decrease.

Examples of the polymerization initiator used in the present invention include azo-based, persulfate- and peroxide-based polymerization initiators, and redox initiators obtained by combining persulfates, peroxides and reducing agents. For example, 2,2'-azobis (2-methylpropionamidine) disulfate, 2,2'-azobis (2-amidinopropane) dihydrochloride, potassium persulfate, ammonium persulfate, benzoyl peroxide, t-butyl hydroperoxide Oxides, hydrogen peroxide, a combination of sulfate and sodium bisulfite, a combination of peroxide and sodium ascorbate, and the like can be mentioned, and one or more of these initiators can be used.

In the present invention, the polymerization initiator is used in an amount of 0.02 to 0.5 part by weight, preferably 0.08 to 0.3 part by weight, based on 100 parts by weight of the monomer mixture. If the amount is less than 0.02 parts by weight, it is difficult to obtain the effect as a polymerization initiator.

In the present invention, a chain transfer agent may be used to adjust the molecular weight of the acrylic polymer. The chain transfer agent is not particularly limited, and examples thereof include 1-dodecanethiol, mercaptoacetic acid, 2-mercaptoethanol, 2-ethylhexyl thioglycolate, and 2,3-dimethylcapto-1-propanol. One or two or more are used depending on the purpose and application.

The natural rubber-based and synthetic rubber-based pressure-sensitive adhesives used in the present invention include natural rubber latex, styrene-butadiene latex, and polyisobutylene latex. These rubber-based pressure-sensitive adhesives can be used by being dissolved in various solvents or emulsified in water with the above-mentioned emulsifier by an appropriate method.

The pressure-sensitive adhesive composition of the present invention may contain various additives as necessary, for example, a cross-linking agent, a release regulator, a tackifier, a plasticizer, a softener, a filler, a pigment, a dye, an aging agent. Inhibitors and the like can be added.

The solid content of the pressure-sensitive adhesive composition of the present invention is not particularly limited, but is desirably 50% by weight or more in order to shorten the drying time after coating. Also, when the viscosity of the pressure-sensitive adhesive composition is high, when coating on a support using the above-described reverse coater, a rib is easily generated on the coated surface, and a pickup roll such as a gravure coater is used. When transferring the pressure-sensitive adhesive to the coating roll by using the same, there is a possibility that a problem that the pressure-sensitive adhesive cannot be picked up may occur, and the viscosity of the pressure-sensitive adhesive composition is 0.4 Pa ·
s or less, preferably 0.3 Pa · s or less, more preferably 0.02 to 0.2 Pa.s. It is preferably s.

The thickness of the pressure-sensitive adhesive composition after drying is not particularly limited, and may be a thickness exceeding 1 mm, but is generally 300 μm or less, preferably 10 to 200 μm, particularly preferably about 20 to 100 μm. Thus, the effect of the present invention appears remarkably.

The support 1 coated with the pressure-sensitive adhesive composition as described above is conveyed to the non-heating section 4 and sent to the defoaming step.

In the defoaming step, the pressure-sensitive adhesive composition applied to the support 1 is kept in a non-heated state in the non-heated section 4.
As a result, bubbles trapped in the pressure-sensitive adhesive layer are released from the surface of the pressure-sensitive adhesive layer, and a pressure-sensitive adhesive layer containing no bubbles can be obtained.

In the drying step, the support 1 passing through the non-heating section 4
To the drying unit 5 for drying. By performing the drying treatment in the drying unit 5, the solvent and the unreacted monomer are removed from the pressure-sensitive adhesive composition of the support 1, and a pressure-sensitive adhesive layer is formed.

In the winding step, the support 1 dried in the drying section 5 is wound in the winding section 6. Thus, an adhesive sheet is manufactured.

As described above, the non-heated portion 4 that maintains the non-heated state after the pressure-sensitive adhesive composition is applied to the support 1 and is heated and dried in the drying portion 5 is provided so that the support 1 is entangled in the pressure-sensitive adhesive layer. Air bubbles are released from the surface of the pressure-sensitive adhesive layer, and by heating and drying this, a pressure-sensitive adhesive sheet containing no air bubbles and having an excellent appearance can be produced.

<Second Embodiment> A schematic structure of an apparatus for manufacturing a pressure-sensitive adhesive sheet according to a second embodiment will be described with reference to FIG. FIG. 2 is a longitudinal sectional view showing a schematic configuration of an apparatus for manufacturing a pressure-sensitive adhesive sheet according to a second embodiment of the present invention.
The differences from the embodiment will be described. In addition, the same parts as those in the first embodiment are denoted by the same reference numerals,
Description is omitted.

That is, in the second embodiment, the non-heating unit 4 is provided above the drying unit 5 as shown in FIG. That is, the support 1 on which the pressure-sensitive adhesive composition has been applied in the application section 3 is once conveyed to the upper portion, and then sent to the non-heating section 4 installed in the upper stage. After the non-heated state is maintained in the non-heated part 4, it is sent to the drying part 5 installed in the lower stage via the turn rolls 41 and 42. At this time, since the surface on which the pressure-sensitive adhesive composition is applied is on the lower side, the pressure-sensitive adhesive composition
The drying method of the floating method which does not contact the floor surface or the wall surface is preferred. Thereafter, the sheet is guided by the guide roll 63 and is wound by the support take-up roll 62. Since the guide roll 63 comes into contact with the pressure-sensitive adhesive layer, it is necessary to use a roll having a high releasability such as a silicone roll.

In the second embodiment, the non-heating unit 4 is replaced with the drying unit 5
By installing it on the upper part, the installation space can be shortened as compared with the first embodiment. Especially when coating at high speed,
It is necessary to lengthen the non-heating part 4 accordingly.
Particularly preferred.

<Third Embodiment> A schematic structure of an apparatus for manufacturing a pressure-sensitive adhesive sheet according to a third embodiment will be described with reference to FIG. FIG. 3 is a longitudinal sectional view showing a schematic configuration of an apparatus for manufacturing a pressure-sensitive adhesive sheet according to a third embodiment of the present invention.
The differences from the embodiment and the second embodiment will be described. In addition, the same parts as those in the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted.

That is, in the third embodiment, the non-heating section 4 is provided above the coating section 3 as shown in FIG. That is, the support 1 on which the pressure-sensitive adhesive composition has been applied in the application section 3 is once conveyed to the upper portion and sent to the non-heating section 4. The support 1 is sent upward in the non-heating section 4 and then returned downward along with the roll. After maintaining the non-heated state during that time, it is turned over by the air knife 7 and sent to the drying section 5 installed below. Thereafter, the sheet is guided by a guide roller 61 and is wound by a support take-up roller 62.

In the third embodiment, the non-heating section 4 is
By installing it on the upper part, the installation space can be shortened as compared with the first embodiment as in the second embodiment. Particularly when the coating is performed at a high speed, the non-heated portion 4 needs to be lengthened accordingly, which is particularly preferable.

<Fourth Embodiment> In the fourth embodiment, after the pressure-sensitive adhesive composition was applied, the time for keeping the non-heated state was changed to change the pressure-sensitive adhesive sheets (first to sixth production examples, first to sixth production examples). A pressure-sensitive adhesive sheet according to a second comparative example was actually manufactured, and the test results in which the degree of foaming of those pressure-sensitive adhesive sheets was compared based on the bubble size and the haze value will be described.

[First Production Example] A monomer mixture consisting of 100 parts by weight of butyl acrylate and 5 parts by weight of acrylic acid was mixed with 3 parts by weight of nonylphenyl polyethylene oxide ammonium sulfate as an emulsifier, 0.1 part of ammonium persulfate as an initiator and Emulsion polymerization was carried out with 96 parts by weight of ion-exchanged water to obtain an aqueous pressure-sensitive adhesive composition having a solid content of 53% by weight and an average particle size of 0.6 μm. This pressure-sensitive adhesive composition was applied to coating section 3
, A 3 m-long floating type drying section in the drying section 5, and a conveyance section with a 3.8 m support roll between the coating section 3 and the non-heating section 4. Using a coating device provided as the heating unit 4, coating and drying were performed at a coating speed of 4 m / min. A 38 μm-thick PET film was used for the support 1, and the thickness of the pressure-sensitive adhesive layer was set to be 70 μm after drying.
The drying conditions of the drying unit 5 are as follows: hot air temperature 110 ° C., wind speed 3
0 m / min. At this time, the time of the non-heating state in which the heating was not performed after the coating was 57 seconds, and the drying time was 45 seconds.

[Second Production Example] Coating and drying were performed in the same manner as in the first production example except that the non-heated portion 4 was changed to 7.2 m. At this time, the time of the non-heating state in which the heating was not performed after the coating was 108 seconds, and the drying time was 45 seconds.

[Third Production Example] Coating and drying were performed in the same manner as in the first production example except that the non-heated portion 4 was 9 m. At this time, the time of the non-heating state in which the heating was not performed after the coating was 135 seconds, and the drying time was 45 seconds.

[Fourth Production Example] In the first production example, except that the non-heating portion 4 was 12 m,
Coating and drying were performed. At this time, the time of the non-heating state in which the heating was not performed after the coating was 180 seconds, and the drying time was 45 seconds.

[Fifth Production Example] In the first production example, except that the non-heating portion 4 was 16 m,
Coating and drying were performed. At this time, the time of the non-heating state in which the heating was not performed after the coating was 240 seconds, and the drying time was 45 seconds.

[Sixth Production Example] In the first production example, except that the non-heating portion 4 was set to 20 m,
Coating and drying were performed. At this time, the time of the non-heating state in which the heating was not performed after the coating was 300 seconds, and the drying time was 45 seconds.

[Seventh Production Example] Coating and drying were performed in the same manner as in the first production example except that the non-heated portion 4 was set to 2.1 m. At this time, the time of the non-heating state where the heating is not performed after the coating is 31.5 seconds, and the drying time is 45 seconds.
Seconds.

[First Comparative Example] In the first manufacturing example, coating was performed in the same manner as in the first manufacturing example except that the non-heating section 4 was not provided and the coating section 3 and the drying section 5 were directly connected. Drying was performed. At this time, after applying the pressure-sensitive adhesive composition to the support, it took 6 seconds for the support to enter the drying section 5, and the drying time was 45 seconds.

(Evaluation Method) The size of the main air bubbles was measured by observing the pressure-sensitive adhesive tapes of Production Examples and Comparative Examples obtained as described above under a microscope (see FIG. 4). The haze value was measured using a film turbidimeter to evaluate the light transmittance of the film. The results are shown in FIG.

As described above, based on the evaluation results of the pressure-sensitive adhesive sheets according to the first to seventh production examples and the first comparative example shown in FIG. It can be seen that, by keeping the provided and unheated state, no bubbles enter the pressure-sensitive adhesive layer, and a pressure-sensitive adhesive sheet having excellent appearance can be obtained.

[0065]

As apparent from the above description, according to the present invention, after the pressure-sensitive adhesive composition is applied on the surface of the support,
By defoaming the pressure-sensitive adhesive composition by keeping the applied pressure-sensitive adhesive composition in a non-heated state, and then heating and drying to remove the solvent from the pressure-sensitive adhesive composition to form a pressure-sensitive adhesive layer, during heat-drying Can be prevented, and a pressure-sensitive adhesive sheet having good appearance and characteristics can be produced. The water-dispersed pressure-sensitive adhesive sheets produced in this manner can be used for various applications, but since they have a good appearance, they can be suitably used, for example, for transparent substrate packaging and optical film applications. it can.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a schematic configuration of an apparatus for producing a pressure-sensitive adhesive sheet according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view illustrating a schematic configuration of an apparatus for manufacturing a pressure-sensitive adhesive sheet according to a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view illustrating a schematic configuration of an apparatus for manufacturing a pressure-sensitive adhesive sheet according to a third embodiment of the present invention.

FIG. 4 is a conceptual diagram of pressure-sensitive adhesive tapes in which bubbles are generated.

FIG. 5 shows evaluation results of pressure-sensitive adhesive sheets of Production Examples and Comparative Examples of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support 2 Support supply roll 3 Coating part 4 Non-heating part 5 Drying part 6 Support winding part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J004 AA04 AA05 AA10 AA11 AA17 AB01 CA02 CA03 CA04 CA05 CA06 CA08 CB01 CB02 EA01 GA01 GA02

Claims (4)

[Claims] 1. A method for producing a pressure-sensitive adhesive sheet for forming a pressure-sensitive adhesive layer by removing a solvent from the pressure-sensitive adhesive composition by heating and drying the pressure-sensitive adhesive composition applied on the surface of a support, comprising: After applying the adhesive composition on the surface of the support, a step of defoaming the adhesive composition by keeping the applied adhesive composition in a non-heated state, and then heating and drying the adhesive composition from the adhesive composition A process for removing a solvent to form a pressure-sensitive adhesive layer. 2. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein after applying the pressure-sensitive adhesive composition on the surface of the support, the pressure-sensitive adhesive composition is defoamed by maintaining a non-heated state for at least 50 seconds. A method for producing a pressure-sensitive adhesive sheet, comprising: 3. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive composition is an aqueous pressure-sensitive adhesive composition. 4. Production of a pressure-sensitive adhesive sheet for producing a pressure-sensitive adhesive sheet for forming a pressure-sensitive adhesive layer by removing a solvent from the pressure-sensitive adhesive composition by heating and drying the pressure-sensitive adhesive composition applied on the surface of a support. In the apparatus, a coating unit for applying a pressure-sensitive adhesive composition on the surface of the support, a drying unit for removing a solvent from the applied pressure-sensitive adhesive composition by heating, and between the coating unit and the drying unit. An apparatus for producing an adhesive tape, further comprising a non-heating section for maintaining a non-heating state.