JP2004073975A - Method and apparatus for producing adhesive tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing an adhesive tape by precisely applying a water-dispersive adhesive on a support and an apparatus for the method. <P>SOLUTION: A liquid supply tank 7 in which the water-dispersive adhesive 3 is stored is covered with a case 11 almost airtightly. The humidity in the tank 7 is detected by a hygrometer 13, and a measured value of the humidity is compared with a standard value by a control part 15 to obtain the variation. Steam is supplied from a humidifier 14 into the case 11 corresponding to the obtained variation. Humidity is kept constant in the inside almost in an airtight condition so that the evaporation of water from the liquid surface of the adhesive 3 in the tank 7 can be prevented. In this way, the mixing of a solid into an adhesive layer by the growth of a dry film can be prevented. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for producing an adhesive tape, and more particularly to a technique for precisely applying an adhesive to a surface of a seal-like or film-like support.
[0002]
[Prior art]
Conventionally, solvent-based pressure-sensitive adhesives are synthesized or dissolved in organic solvents, and therefore, volatilization of the solvent during coating has become an environmental problem. It has been attempted to convert to a water-dispersed pressure-sensitive adhesive obtained by dispersing or emulsifying the same.
[0003]
As a method for producing a pressure-sensitive adhesive tape using a water-dispersed pressure-sensitive adhesive, the following modes are employed. For example, a water-dispersed pressure-sensitive adhesive is applied to an appropriate thickness on a support such as a film, and the coated support is dried to obtain a pressure-sensitive adhesive tape. A method for producing a tape is known.
[0004]
Specifically, as shown in FIG. 4, the support 1 is supplied from the support supply roll 2 to a roll coater that is the adhesive coating unit 4. In the pressure-sensitive adhesive coating unit 4, the water-dispersed pressure-sensitive adhesive 3 in the liquid supply tank 7 is transported by the coating roll 8, and the pressure-sensitive adhesive 3 is coated on the surface of the support 1. The support 1 to which the adhesive 3 has been applied is passed through a drying unit 5 to remove excess solvent by drying. A roll-shaped pressure-sensitive adhesive tape is manufactured by winding the support 1 after the drying treatment into a roll.
[0005]
[Problems to be solved by the invention]
However, the conventional adhesive tape manufacturing apparatus has the following problems.
In other words, in the case of a conventional device such as a comma coater, which has an adhesive coating unit whose supply tank is open to the atmosphere, if the adhesive is applied for a long time, the water evaporates from the adhesive to the atmosphere and The particles fuse to form a dry film on the liquid surface. The dried film is mixed in the adhesive by, for example, settling on the adhesive, and is applied to the support as it is.
[0006]
Therefore, there is a problem in that a dry film is mixed as a solid substance into the adhesive layer of the adhesive tape to be produced, which causes poor characteristics and poor appearance such as a decrease in the contact area of the adhesive tape with the adherend.
[0007]
In order to prevent the formation of the dried film, as shown in FIG. 5, the pressure-sensitive adhesive is pumped up from the vicinity of the center of the liquid supply tank 7 by the pump P, and the pumped-up adhesive is again applied to the side wall of the liquid supply tank 7. A means is adopted for convection circulation by returning from near. In this case, air is entrained in the process of circulating the adhesive, and many air bubbles are mixed in the adhesive.
[0008]
When the pressure-sensitive adhesive mixed with the air bubbles is applied to a support and subjected to a drying treatment, the air bubbles are foamed and unevenness is generated on the adhesive surface. Therefore, there is also a problem that poor characteristics and poor appearance such as a reduction in the contact area of the adhesive tape with the adherend occur.
[0009]
The present invention has been made in view of such circumstances, and a main object of the present invention is to provide a method of manufacturing a pressure-sensitive adhesive tape for accurately applying a pressure-sensitive adhesive to a support, and a device therefor.
[0010]
[Means for Solving the Problems]
The present invention has the following configuration to achieve such an object.
That is, the invention according to claim 1 applies a water-dispersed pressure-sensitive adhesive stored in a liquid storage portion to a support, and performs a drying process on the support coated with the pressure-sensitive adhesive to form a pressure-sensitive adhesive layer. In the method for producing the obtained adhesive tape,
The liquid reservoir is made substantially airtight, and a water-dispersed pressure-sensitive adhesive is applied to the support while controlling the humidity in the atmosphere inside the liquid reservoir.
[0011]
(Operation / Effect) According to the first aspect of the present invention, the liquid reservoir is made substantially airtight, and the humidity in the atmosphere inside the liquid reservoir is controlled. Therefore, the evaporation of water from the water-dispersed pressure-sensitive adhesive is eliminated, and the generation of a dry film due to the fusion of the pressure-sensitive adhesive particles is prevented. As a result, when the pressure-sensitive adhesive is applied to a support, It is possible to eliminate the characteristic defect and the poor appearance of the pressure-sensitive adhesive caused by the inclusion of the substance.
[0012]
Further, the invention according to claim 2 provides a support supply means, a pressure-sensitive adhesive coating means for coating a water-dispersed pressure-sensitive adhesive on the supplied support, and the water-dispersed pressure-sensitive adhesive. In a device for producing an adhesive tape, comprising:
The pressure-sensitive adhesive coating means, a liquid reservoir for supplying a water-dispersed pressure-sensitive adhesive,
A roll for applying the water-dispersed pressure-sensitive adhesive supplied from the liquid reservoir to the support,
Airtight means for covering the liquid reservoir and making it substantially airtight,
Humidity detection means for detecting the humidity in the atmosphere in a substantially airtight state by the airtight means,
Humidifying means for humidifying the inside of the substantially airtight state by the airtight means,
Control means for controlling the humidifying means so as to adjust the humidity in the substantially airtight atmosphere based on the result detected by the humidity detecting means.
[0013]
According to the second aspect of the present invention, the humidity in the atmosphere is detected by the humidity detecting means in a state where the liquid reservoir is made substantially airtight by the airtight means. Based on the detection result, the control means operates the humidifying means to control the humidity in the atmosphere of the substantially airtight liquid reservoir. Therefore, the method of claim 1 can be suitably realized.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
A schematic configuration of an apparatus for manufacturing an adhesive tape according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic side view showing an example of a pressure-sensitive adhesive tape manufacturing apparatus according to the present invention, and FIG. 2 is a perspective view showing a main part configuration of a pressure-sensitive adhesive coating section.
[0015]
As shown in FIG. 1, the apparatus for manufacturing an adhesive tape according to the present embodiment includes a support supply roll 2 serving as support supply means for feeding and supplying a support 1 such as a sheet, a tape, or a film. A pressure-sensitive adhesive coating unit 4 for coating a water-dispersible pressure-sensitive adhesive 3 to a predetermined thickness on the surface of the support 1 fed from the support supply roll 2, and a water-dispersible pressure-sensitive adhesive coated on the support 1 A drying unit 5 for drying and removing the unnecessary solvent of the pressure-sensitive adhesive 3 and a collecting unit 6 for winding and collecting the dried support 1. Hereinafter, the configuration of each unit will be described in detail.
[0016]
The support 1 is not particularly limited as long as it has the necessary strength as a tape. For example, papers (Japanese paper, kraft paper, etc.), cloths (cotton, cloth, synthetic fiber, non-woven fabric, etc.), plastics (cellophane, polypropylene, ethylene, propylene copolymer / polyester, polyethylene, polyethylene, polyvinyl chloride, acetate, A porous material such as polystyrene or polyacrylonitrile, a gold foil, or a plastic laminate of these materials can be used. Further, a film or foam made of a polymer having rubber-like elasticity can also be used.
[0017]
Further, the thickness of the support 1 is appropriately determined according to the material to be used, the application, and the purpose. For example, in this embodiment, the thickness is set to 200 μm or less.
[0018]
Further, the support 1 may be subjected to various treatments such as an undercoating treatment, a sealing treatment, a corona treatment, and a back surface treatment.
[0019]
The pressure-sensitive adhesive coating unit 4 is for coating the surface of the support 1 with the water-dispersed pressure-sensitive adhesive 3 so as to have a predetermined width and a predetermined thickness in the width direction of the support 1. The pressure-sensitive adhesive coating unit 4 includes a liquid supply tank 7 for supplying the water-dispersed pressure-sensitive adhesive 3, and a pressure-sensitive adhesive 3 coated on the surface of the support 1 with a predetermined width. A coating roll 8 for adhering and conveying the adhesive 3 having a predetermined width, a comma roll 9 for controlling the thickness of the adhesive 3 adhered to the coating roll 8, and a support 1 for gripping and conveying the support 1 with the coating roll 8. And a backup roll 10 that performs the backup. The pressure-sensitive adhesive coating unit 4 corresponds to the pressure-sensitive adhesive coating means of the present invention, and the liquid supply tank 7 corresponds to a liquid reservoir.
[0020]
The liquid supply tank 7 is covered with a case 11 in order to keep the stored pressure-sensitive adhesive 3 substantially airtight without directly touching the outside air. More specifically, as shown in FIGS. 1 and 2, the case 11 is a box type having the coating roll 8 and the comma roll 9 open. Each side wall is formed such that the case opening surface is close to the curved surfaces of both rolls 8 and 9. The distance to which the case 11 approaches is set such that each side wall does not hinder the rotational driving of both rolls 8 and 9. Note that the case 11 corresponds to the hermetic means of the present invention.
[0021]
The configuration of the pressure-sensitive adhesive coating unit 4 is not limited to the comma coater described above, and a coating method in which the pressure-sensitive adhesive coating unit 4 is opened such as a roll coater, a reverse coater, a kiss coater, and a gravure coater. Can also be used.
[0022]
As shown in FIG. 1, the case 11 is provided with an adhesive supply unit 12, a hygrometer 13, a humidifier 14, and a level gauge L, and these operations are controlled by the control unit 15. ing. Note that the hygrometer 13 corresponds to a humidity detecting unit of the present invention, the humidifier 14 corresponds to a humidifying unit, and the control unit 15 corresponds to a control unit.
[0023]
The adhesive supply unit 12 is for supplying the adhesive 3 to the liquid supply tank 7, and the supply amount and the supply timing are adjusted by the control unit 15. For example, as shown in FIG. 1, a level gauge L is provided in the liquid supply tank 7 to sequentially detect the liquid level of the adhesive 3 in the liquid supply tank 7, and based on the detection result, the liquid level is kept constant. The pressure-sensitive adhesive 3 may be continuously supplied so as to keep the pressure-sensitive adhesive. Alternatively, the pressure-sensitive adhesive 3 may be supplied when the liquid level drops to a predetermined height.
[0024]
The hygrometer 13 detects the humidity inside the case 11 and sends the result to the control unit 15. The timing of detecting the humidity is not particularly limited, and can be set arbitrarily.
[0025]
The humidifier 14 is for sending steam into the case 11. The feeding of the steam is adjusted by the control unit 15. Specifically, the humidity (reference value) inside the case 11 is set in the control unit 15 in advance in accordance with each adhesive 3, and the reference value and the humidity (actually measured value) detected from the hygrometer 13 in a timely manner are calculated. The steam is supplied from the humidifier 14 into the case 11 so that the humidity in the case 11 becomes a reference value in accordance with the obtained change amount. The inside of the case 11 may be controlled based on the relative humidity.
[0026]
In the present embodiment, the humidity of the liquid supply tank 7 is set to be 70% or more, but preferably 80% or more. When the content becomes 70% or less, evaporation of water from the water-dispersed pressure-sensitive adhesive starts, and fusion of pressure-sensitive adhesive particles occurs. That is, a solid that is a dry film is generated, and the solid is applied to the support 1, resulting in poor appearance and characteristics of the adhesive tape.
[0027]
As the water-dispersible pressure-sensitive adhesive 3 used in the present example, for example, an acrylic, natural rubber, or synthetic rubber-based pressure-sensitive adhesive or a mixture thereof is dispersed in water using an emulsifier or a dispersant as appropriate. What was made can be used.
[0028]
Acrylic water-dispersed pressure-sensitive adhesives include (meth) acrylic acid ester, which is a main monomer, for stabilizing emulsion particles, improving the adhesiveness of the pressure-sensitive adhesive layer to support 1, and improving initial adhesion to an adherend. For the purpose of improving the adhesiveness and the like, a functional group-containing vinyl monomer may be used in combination, and emulsion polymerization may be appropriately performed using an emulsifier and a polymerization initiator.
[0029]
As the (meth) acrylate, a wide variety of monomers or monomer mixtures can be used. For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, sec (meth) acrylate -Butyl, t-butyl (meth) acrylate, pentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, (meth) Isooctyl acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, (meth) ) Myristyl acrylate, pentadecyl (meth) acrylate, Such as acrylic acid stearyl, and the like.
[0030]
These (meth) acrylic acid esters are preferably used at 60 to 99% by weight of the total monomer mixture. If it is less than 60% by weight, the adhesive properties may be impaired.
[0031]
The amount of the functional group-containing vinyl monomer is appropriately set within a range of 40% by weight or less of the total monomer mixture, depending on the type of each monomer. In order to obtain good pressure-sensitive adhesiveness, it is preferable to determine the amount of the polymer to be used so that the glass transition point of the obtained polymer is usually −20 ° C. or lower.
[0032]
Examples of the functional group-containing vinyl monomer copolymerizable with the (meth) acrylic ester include acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, crotonic acid, maleic acid, fumaric acid, and hydroxy (meth) acrylate. Functional monomers such as alkyl, glycerin dimethacrylate, glycidyl (meth) acrylate, methyl glycidyl methacrylate, aminoethyl (meth) acrylate, 2-methacryloyloxyethyl isocyanate, triethylene glycol diacrylate, ethylene glycol dimethacrylate, Multifunctional monomers such as trimethylolpropane tri (meth) acrylate, vinyl acetate, styrene, (meth) acrylonitrile, N-vinylpyrrolidone, (meth) acryloylmorpholine, cyclohexyl maleimi , Isopropyl maleimide, and (meth) acrylamide.
[0033]
Examples of the natural rubber-based and synthetic rubber-based pressure-sensitive adhesives used in this example include a natural rubber latex-based adhesive and a styrene-butadiene latex-based adhesive.
[0034]
As the emulsifier used in this embodiment, a commonly used anionic or non-anionic emulsifier can be used. Examples of the anionic emulsifier include sodium lauryl sulfate, ammonium laurate, sodium dodecylbenzene sulfonate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, sodium polyoxyethylene alkyl sulfosuccinate, and the like. Also. For example, a radical polymerizable emulsifier into which a propenyl group or the like has been introduced may be used.
[0035]
Examples of the non-anionic emulsifier include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene polyoxypropylene block polymer.
[0036]
One or two or more of the above-mentioned anionic or non-anionic emulsifiers can be used depending on the type of the monomer.
[0037]
In this example, the emulsifier is used in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the monomer mixture. Preferably, it is used in the range of 0.4 to 3.0 parts by weight. Thus, by setting the range of the amount of the emulsifier to be used, a water-dispersed pressure-sensitive adhesive excellent in water resistance and adhesiveness can be obtained.
[0038]
Examples of the polymerization initiator used in this example include azo-based, persulfate, and peroxide-based polymerization initiators, persulfates, and a redox initiator obtained by combining a peroxide and a reducing agent. For example, 2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis (2-amidinopropane) dihydrochloride, potassium persulfate, ammonium persulfate, benzoyl peroxide, t-butyl hydroperoxide Oxide, hydrogen peroxide, a combination of sulfate and sodium bisulfite, a combination of peroxide and sodium ascorbate, and the like can be given. One or more of these polymerization initiators can be used.
[0039]
In this example, the polymerization initiator is used in a range of 0.02 to 0.5 part by weight based on 100 parts by weight of the monomer mixture. Preferably, it is used in the range of 0.08 to 0.3 parts by weight. If the amount of the polymerization initiator is less than 0.02 parts by weight, it is difficult to obtain the effect as a polymerization initiator, and if the amount is more than 0.5 parts by weight, the molecular weight tends to decrease, and poor properties as an adhesive occur.
[0040]
In this embodiment, 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. Can be One or more chain transfer agents are used depending on the purpose and use.
[0041]
Various additives are blended in the water-dispersed pressure-sensitive adhesive 3 used in the present embodiment, if necessary. As the additive, for example, a cross-linking agent, a release regulator, a tackifier, a plasticizer, a softener, a filler, a pigment, a dye, an antioxidant, and the like are blended.
[0042]
Further, the particle size of the polymer of the water-dispersed pressure-sensitive adhesive may be 0.1 to 3.0 μm, preferably 0.2 to 1.0 μm, as long as it has good mechanical stability and coatability. It is adjusted to. When the particle size is smaller than 0.1 μm, the viscosity of the water-dispersed pressure-sensitive adhesive is too high. On the other hand, when the particle diameter is larger than 3.0 μm, the cohesive force is also reduced due to the decrease in the fusibility between the particles.
[0043]
The solid content concentration of the water-dispersed pressure-sensitive adhesive 3 is not particularly limited, but is preferably 40 to 60% by weight in order to shorten the drying time after coating.
[0044]
The thickness of the composition obtained after drying the pressure-sensitive adhesive is not particularly limited, and may be more than 1 mm, but is generally 500 μm. It is preferably about 3 to 300 μm, and more preferably 5 to 200 μm.
[0045]
Returning to FIG. 1, the drying section 5 is for drying and removing an unnecessary solvent from the adhesive 3 applied to the support 1. The drying unit 5 includes, for example, a drying oven. The drying unit 5 corresponds to a drying unit of the present invention.
[0046]
The collecting section 6 is for collecting the support body 1 which has been subjected to the drying process and has become the adhesive tape conveyed through the guide roller 16 group, by winding it on a roll. It is desirable that the collection unit 6 be provided with a winding correction device in order to prevent a winding deviation. Note that the collection unit 6 corresponds to the collection unit of the present invention.
[0047]
Next, a manufacturing process for manufacturing the pressure-sensitive adhesive tape using the embodiment apparatus configured as described above will be described below.
[0048]
First, a humidity reference value or the like corresponding to the adhesive to be used is initially set. Thereafter, the support 1 is fed out of the support supply roll 2 while being gripped by the interlocking drive of the coating roll 8 and the backup roll 10.
[0049]
The support 3 that has moved to the pressure-sensitive adhesive coating section 4 is coated with the pressure-sensitive adhesive 3 adhered to the surface of the coating roll 8 and transported.
[0050]
The support 1 having the surface coated with the adhesive 3 passes through the drying section 5, and in the process, unnecessary solvent contained in the adhesive 3 is dried and removed.
[0051]
The support 1 that has been subjected to the drying treatment is conveyed to the collection unit 6 via the guide rolls 16 and wound up and collected by the rolls 17.
[0052]
While the above operation is being performed, the humidity in the case 11 of the adhesive coating unit 4 is sequentially detected by the hygrometer 13 and sent to the control unit 15. The control unit 15 compares the humidity in the case 11 obtained based on the detection result with a reference value set and input in advance, and controls the humidifier so that the humidity in the case 11 becomes constant according to the obtained change amount. The supply of steam from 14 is regulated.
[0053]
Further, the detection result from the level gauge L is sent to the control unit 15. The control unit 15 controls the supply amount of the adhesive 3 to be supplied from the adhesive supply unit 12 to the liquid supply tank 7 so that the liquid level of the liquid supply tank 7 becomes constant based on the detection result.
[0054]
Hereinafter, a specific example of the pressure-sensitive adhesive tape obtained by using the example device shown in FIGS. 1 and 2 and a comparative example of the pressure-sensitive adhesive tape obtained by using the conventional device shown in FIGS. 4 and 5 are shown. .
[0055]
<Specific example>
In this specific example, an experiment was conducted in which an adhesive tape was manufactured using the apparatus for manufacturing an adhesive tape shown in FIG. Various setting conditions for manufacturing the adhesive tape are as follows.
[0056]
The water-dispersed acrylic pressure-sensitive adhesive 3 was stored in the liquid supply tank 7, and the humidity in the case 11 was controlled to be 85 ± 5%. In this state, the adhesive 3 is applied to the surface of the support 1 so as to have a thickness of 100 μm by a comma coater while the 50 μm-thick polyester support 1 is transported at a coating speed of 15 m / min. Tape was manufactured. In this specific example, the transparent case 11 was used so that the liquid surface state of the adhesive 3 in the liquid supply tank 7 could be visually checked in the process of manufacturing the adhesive tape.
[0057]
The water-dispersed pressure-sensitive adhesive (solution) was obtained as follows. 40 parts by weight of ion-exchanged water is placed in a reactor (stirrer) equipped with a thermometer, an anchor-type stirring blade (with a blade width of 100 mm), a nitrogen inlet tube, and a reflux cooling tube, and is purged with nitrogen for 1 hour while stirring. I let it. After the replacement, 0.1 part by weight of potassium persulfate was added as an initiator, the temperature inside the reactor was raised to 70 ° C., and then 97 parts by weight of butyl acrylate, 3 parts by weight of acrylic acid, and polyoxyethylene alkyl A solution obtained by emulsifying 0.5% by weight of sodium sulfosuccinate ("Newcol 293" manufactured by Nippon Emulsifier Co., Ltd.) and 35 parts by weight of water was added dropwise over 3 hours, emulsion-polymerized, and reacted with 10% ammonia. It was neutralized with water to obtain a water-dispersed acrylic pressure-sensitive adhesive having a solid content of 54% by weight and an average particle diameter of 400 nm.
[0058]
<Comparative example>
In this comparative example, as shown in FIG. 4, the case 11 of the adhesive coating unit 4 in FIG. 1 is removed, and the liquid supply tank 7 is open to the atmosphere. The water-dispersed acrylic pressure-sensitive adhesive 3 was applied to the support 1 in a state where the average humidity in the atmosphere was 50%. Otherwise, the experiment was performed under the same conditions as in the above specific example.
[0059]
As a result of the experiment, in this specific example, no dry film was formed on the liquid surface of the liquid supply tank 7 in the process of manufacturing the adhesive tape. Therefore, when the pressure-sensitive adhesive layer of the produced pressure-sensitive adhesive tape was visually confirmed, no solid matter was found in the dried film, and no poor properties and appearance occurred.
[0060]
In the comparative example, a dried film began to be formed on the liquid level in the liquid supply tank 7 after about one hour in the manufacturing process. When the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape was visually inspected after the end of the production, mixing of solids in the dried film was observed. In particular, at locations where the solids were extremely mixed, the pressure-sensitive adhesive 3 was not applied in a line. Therefore, the produced pressure-sensitive adhesive tape had poor appearance and characteristics.
[0061]
As described above, in the present embodiment, the liquid supply tank 7 is covered with the case 11 so as to be substantially airtight, and the humidity in the atmosphere inside the liquid supply tank 7 is controlled so that the pressure-sensitive adhesive 3 in the liquid supply tank 7 is reduced. Evaporation of water from the liquid surface can be prevented. Therefore, it is possible to prevent the occurrence of a dry film on the liquid surface due to the opening to the atmosphere, so that when the pressure-sensitive adhesive 3 is applied to the support 1, the solid matter of the dry film does not enter the pressure-sensitive adhesive layer. Characteristic defect and appearance defect due to the mixing of the metal can be eliminated.
[0062]
The present invention is not limited to the above-described embodiment, but can be modified as follows.
[0063]
(1) In the above embodiment, the case 11 was used to keep the liquid supply tank 7 substantially airtight. However, the present invention is not limited to this mode, and the inside of the liquid supply tank 7 is kept almost airtight. Any configuration can be used as long as it can control the humidity or the relative humidity inside. For example, a lid member may be provided in the liquid supply tank 7 so that the inside of the liquid supply tank 7 itself is airtight, or the entire adhesive coating unit 4 is covered with a case to be substantially airtight, The humidity in the atmosphere may be controlled.
[0064]
(2) In the above embodiment, the pressure-sensitive adhesive 3 is additionally supplied from the pressure-sensitive adhesive supply section 12 to the liquid supply tank 7. You may comprise so that it may circulate.
[0065]
(3) In the above embodiment, the support 1 was gripped and transported by the coating roll 8 and the backup roll 10, but as shown in FIG. 1 may be conveyed.
[0066]
【The invention's effect】
As is apparent from the above description, according to the present invention, the evaporation of water from the adhesive is suppressed by making the liquid reservoir that is open to the atmosphere substantially airtight and controlling the humidity in the atmosphere inside the reservoir. It is possible to prevent a dry film generated on the liquid surface. As a result, it is possible to eliminate the incorporation of solids of the dried film in the adhesive layer formed on the surface of the support by applying the adhesive, and to eliminate the characteristic defect and the appearance defect in which the contact area with the adherend is reduced. can do.
[Brief description of the drawings]
FIG. 1 is a side view showing a schematic configuration of a pressure-sensitive adhesive tape manufacturing apparatus according to an embodiment.
FIG. 2 is a perspective view showing a configuration of a main part of an adhesive coating unit.
FIG. 3 is a side view illustrating a schematic configuration of a modified example device.
FIG. 4 is a side view showing a schematic configuration of a conventional adhesive tape manufacturing apparatus.
FIG. 5 is a perspective view showing a configuration of a main part of a pressure-sensitive adhesive coating section of a conventional device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Support 2 ... Support supply roll 4 ... Adhesive coating part 5 ... Drying part 6 ... Recovery part 7 ... Liquid supply tank 11 ... Case 13 ... Hygrometer 14 ... Humidifier 15 ... Control part

Claims (2)

A method for producing a pressure-sensitive adhesive tape, in which a water-dispersed pressure-sensitive adhesive retained in a liquid reservoir is applied to a support, and the pressure-sensitive adhesive applied to the support is dried to obtain a pressure-sensitive adhesive layer.
A method for producing a pressure-sensitive adhesive tape, comprising: applying a water-dispersed pressure-sensitive adhesive to a support while controlling the humidity in an atmosphere inside the liquid reservoir in a substantially airtight state. Support supply means, pressure-sensitive adhesive coating means for applying a water-dispersed pressure-sensitive adhesive to the supplied support, and drying means for drying the support coated with the water-dispersed pressure-sensitive adhesive, In an apparatus for manufacturing an adhesive tape having
The pressure-sensitive adhesive coating means, a liquid reservoir for supplying a water-dispersed pressure-sensitive adhesive,
A roll for applying the water-dispersed pressure-sensitive adhesive supplied from the liquid reservoir to the support,
Airtight means for covering the liquid reservoir and making it substantially airtight,
Humidity detection means for detecting the humidity in the atmosphere in a substantially airtight state by the airtight means,
Humidifying means for humidifying the inside of the substantially airtight state by the airtight means,
A device for manufacturing an adhesive tape, comprising: control means for controlling the humidifying means so as to adjust the humidity in a substantially airtight atmosphere based on the result detected by the humidity detecting means.

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