JP2003147289A - Manufacturing method of double-sided adhesive tape - Google Patents

Abstract

(57) Abstract: The present invention relates to a water-dispersed double-sided pressure-sensitive adhesive tape that does not use an organic solvent that has an adverse effect on the environment. An object of the present invention is to provide a method for producing a double-sided pressure-sensitive adhesive tape, which can solve the conventional problem of extremely low productivity because layers are formed in separate steps. The present invention relates to a method for producing a double-sided pressure-sensitive adhesive tape, in which a water-dispersed pressure-sensitive adhesive composition is directly applied to a support to produce a double-sided pressure-sensitive adhesive tape.
Water) in a non-woven fabric having a tensile strength (MD direction) of 2.0 N / 15 mm or more and a wet elongation (MD direction) of 15% or less. The present invention relates to a method for producing a double-sided pressure-sensitive adhesive tape, in which a double-sided pressure-sensitive adhesive composition is directly applied to produce a double-sided pressure-sensitive adhesive tape.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a double-sided pressure-sensitive adhesive tape having a water-dispersible pressure-sensitive adhesive layer on both sides of a nonwoven fabric.

[0002]

2. Description of the Related Art Conventionally, solvent-type pressure-sensitive adhesives have been mainly used as pressure-sensitive adhesives. However, since these solvent-type pressure-sensitive adhesives are synthesized or dissolved in an organic solvent, volatilization of the solvent at the time of coating is environmentally problematic, and water containing a pressure-sensitive adhesive particle dispersed or emulsified in an aqueous medium is used. Conversion to a dispersion type adhesive is being attempted.

The double-sided pressure-sensitive adhesive tape has a structure in which a pressure-sensitive adhesive layer is provided on both sides of a support, but conventionally, the pressure-sensitive adhesive layers formed on both sides of the support are formed on separate release papers. After that, it has been manufactured by bonding it to a support. Then, it is in the form of being wound into a roll through a release paper having a releasability for the adhesive.

That is, the first step is shown in FIG.
As shown in, the release paper 10 whose both surfaces are release-treated with a silicone-based release treatment agent, a long-chain alkyl-based release treatment agent, or the like.
From the release paper supply roll 20 on which the release paper 1 is wound
0 is supplied, the pressure-sensitive adhesive composition is applied to a desired thickness by the coating unit 3, and the pressure-sensitive adhesive composition applied to the release paper 10 by the drying unit 4 is heated to remove the pressure-sensitive adhesive composition from the pressure-sensitive adhesive composition. The solvent was removed, and the support 11 supplied from the support supply roll 21 was laminated on the pressure-sensitive adhesive composition on the release paper 10 that was heated and dried by the bonding unit 5 in the drying unit 4, and the obtained laminate was obtained. 30 is wound up by the laminated body roll 22.

Next, as a second step, as shown in FIG. 1 (b), the process paper 12 is fed from the peeled process paper supply roll 23 and the coating composition 3 is used to apply the adhesive composition to a desired thickness. And the solvent was removed from the pressure-sensitive adhesive composition by heating the pressure-sensitive adhesive composition applied to the process paper 12 by the drying unit 4 and heated and dried by the bonding unit 5 in the drying unit 4. The laminate 30 supplied from the laminate roll 22 produced in the first step is laminated on the pressure-sensitive adhesive composition on the process paper 12 so that the pressure-sensitive adhesive layers are present on both sides of the support, and then the process paper 12 is added. Peel off from the adhesive layer and wind with the process paper winding roll 24,
The obtained double-sided adhesive tape is wound on a double-sided adhesive tape winding roll 25.

[0006]

Therefore, in the conventional method for producing a double-sided pressure-sensitive adhesive tape, an unnecessary process paper is required as the final product, and the cost is accordingly increased, and the two-layer pressure-sensitive adhesive layer is required. Since they are manufactured in separate steps, they have a problem of extremely poor productivity.

The present invention provides a water-dispersible double-sided pressure-sensitive adhesive tape which does not use an organic solvent which has an adverse effect on the environment, does not use unnecessary process paper as a final product, and separates two pressure-sensitive adhesive layers in separate steps. A double-sided pressure-sensitive adhesive tape capable of improving the conventional problem of extremely poor productivity for production and producing water-dispersible double-sided pressure-sensitive adhesive tapes having a pressure-sensitive adhesive layer on both sides of a support in one step. It aims at providing the manufacturing method of.

[0008]

Means for Solving the Problems The inventors of the present invention have made extensive studies to solve the above-mentioned problems, and if a specific non-woven fabric is used, an unnecessary process paper is not used as a final product and a water-dispersed type is used. The present invention has been completed by finding a manufacturing method capable of applying and drying two pressure-sensitive adhesive layers of a double-sided pressure-sensitive adhesive tape in one step.

That is, the present invention is a method for producing a double-sided pressure-sensitive adhesive tape (claim 1) in which a water-dispersed pressure-sensitive adhesive composition is directly applied to a support, which is particularly wet as a support. Tensile strength (MD direction) is 2.0 N / 1
A double-sided pressure-sensitive adhesive tape manufacturing method (claim 2) in which a water-dispersible pressure-sensitive adhesive composition is directly applied to a non-woven fabric of 5 mm or more, and a tensile strength (MD direction) when wet is 2.0 N. / 15 mm or more and elongation when wet (M
The present invention relates to a double-sided pressure-sensitive adhesive tape manufacturing method (claim 3) in which a water-dispersible pressure-sensitive adhesive composition is directly applied to a nonwoven fabric having a D direction of 15% or less.

The present invention is also a method for producing the double-sided pressure-sensitive adhesive tape, wherein the water-dispersible pressure-sensitive adhesive composition is directly coated on the upper and lower surfaces of the support to produce the double-sided pressure-sensitive adhesive tape. The present invention relates to a method (Claim 4) and a method for manufacturing a double-sided pressure-sensitive adhesive tape (Claim 5) in which a water-dispersed pressure-sensitive adhesive composition is applied using a die coater.

[0011]

The operation of the invention described in claim 1 is as follows. By directly applying the water-dispersed pressure-sensitive adhesive composition to the support and drying it, a double-sided pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on both sides of the support can be produced by a single coating and drying step. . Therefore, according to the invention as set forth in claim 1, the double-sided adhesive layer can be produced in one step, and the double-sided adhesive tape can be produced without using process paper unnecessary for the final product as in the prior art. Since it can be manufactured, the manufacturing cost can be kept low.

According to the second aspect of the invention, when a nonwoven fabric is used as the support, the tensile strength (MD direction) when the nonwoven fabric is wet is 2.0 N / 15 mm or more. It can be applied and dried without breaking the body.

According to the invention of claim 3, when a nonwoven fabric is used as the support, the tensile strength (MD direction) of the nonwoven fabric when wet is 2.0 N / 15 mm or more, and the elongation when wet ( Since the MD direction) is 15% or less, the support can be coated and dried without being cut during the manufacturing process, and the support can be wound neatly without wrinkles.

According to the fourth aspect of the present invention, the water-dispersed pressure-sensitive adhesive composition is directly applied to the upper and lower surfaces of the nonwoven fabric to produce a double-sided pressure-sensitive adhesive tape. Therefore, an appropriate pressure-sensitive adhesive composition layer can be provided on each of the upper surface and the lower surface,
Further, its thickness can be adjusted individually.

According to the invention of claim 5, a water-dispersible pressure-sensitive adhesive composition is applied using a die coater to produce a double-sided pressure-sensitive adhesive tape. Therefore, the water-dispersed pressure-sensitive adhesive composition can be applied to both surfaces of the support in a space-saving manner.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a schematic configuration of the entire apparatus for manufacturing a double-sided pressure-sensitive adhesive tape according to an embodiment of the present invention.

The adhesive tape manufacturing apparatus according to this embodiment is
As shown in FIG. 2, it is roughly divided into a sheet shape, a tape shape,
Alternatively, a support supply roll 21 around which a support 11 in the form of a film is wound, and the support supply roll 21
Coating part 3 for directly coating the pressure-sensitive adhesive composition on the support 11 from above to a desired thickness, and heating the pressure-sensitive adhesive composition coated on the support 11 to remove the solvent from the pressure-sensitive adhesive composition. A drying section 4 for removing the adhesive to form a pressure-sensitive adhesive layer, and a release paper 10 supplied from a release paper supply roll and having releasability on both sides, from the upper side or the lower side of the support 11 heated and dried in the drying section 4. It is composed of a bonding section 5 that can be joined and a double-sided adhesive tape winding section 25 that winds up this laminated body. Hereinafter, the configuration of each unit will be described in detail.

The support supply roll 21 is wound around the support 11 in the form of a sheet, a tape, a film, or the like.

The support used in the present invention is, for example, paper (Japanese paper, kraft paper, etc.), cloth (cotton, staple, synthetic fiber, non-woven 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. Alternatively, a film or a foam made of a rubber-like polymer having elasticity may be used. The thickness thereof is usually 200 μm or less, but it can be appropriately determined depending on the type, use and purpose of the substrate used. Further, the base material may be one that has been subjected to known processing such as undercoating treatment, sealing treatment, corona treatment, and back surface treatment.

Generally, the non-woven fabric used as a support for the double-sided adhesive tape is a paper product which is inexpensive and has good hand-cutting properties. It has poor water resistance and has a tensile strength when dried with respect to a tensile strength when dried. The strength is significantly reduced. However, when impregnated with an organic solvent, its strength is not reduced. Therefore, when a solvent-type pressure-sensitive adhesive composition is used, no problem occurs, but when the water-dispersed pressure-sensitive adhesive composition is directly applied to the nonwoven fabric, there is a problem that the nonwoven fabric is cut during drying.

In the present invention, a nonwoven fabric having high water resistance is used as the support, and as an index thereof, the tensile strength when wet is 2.0 N / 15 mm or more, preferably 5.0 N / 15 mm or more, more preferably Is 10N / 15
It is desirable that it is mm or more. When the tensile strength when wet is less than 2.0 N / 15 mm, when the nonwoven fabric is coated with the water-dispersed pressure-sensitive adhesive composition, there is a problem that the nonwoven fabric is cut in the dry part, and therefore it cannot be used. Also, it is desirable that the elongation is small, and the elongation when wet is 15% or less, preferably 10%.
The following is desirable. If the support is stretched by 15% or more, wrinkles may occur on the support, and a problem that the support may not be wound up neatly may occur.

The tensile strength and elongation when wet are
It is a value measured according to JIS L-1096 (wet strength measurement method).

The coating unit 3 directly coats the pressure-sensitive adhesive composition on the support 11 from the support supply roll 21 so as to have a desired width in the width direction of the support 11 and a desired thickness. It is for doing. The coating unit 3 includes, for example, a supply tank 31 for supplying the pressure-sensitive adhesive composition, and the pressure-sensitive adhesive composition supplied from the supply tank 31 according to a desired width of the support 11 directly to the support 11. The die coater 32 for coating is provided, and the water-dispersed pressure-sensitive adhesive composition can be directly coated on the upper surface and the lower surface of the support. At this time, the water-dispersed pressure-sensitive adhesive composition applied to the upper surface and the lower surface of the support may be the same composition, but different compositions may be applied depending on the application. Further, the thickness of the pressure-sensitive adhesive composition layer can be adjusted individually.

When a highly air-permeable support is used as the support, the pressure-sensitive adhesive composition can be exuded on the opposite surface by coating the pressure-sensitive adhesive composition from one direction and simultaneously form a pressure-sensitive adhesive layer. It is also possible. In this way, the pressure-sensitive adhesive composition is directly applied to the support 11 so that the support 11 has a desired width and a desired thickness.

The coating unit 3 can be preferably used because the die coater as described above can be installed in a small space and has good production efficiency, but the present invention is not limited to this and is not limited to a comma. Coater, roll coater,
Other coating methods such as a gravure coater may be used, and the method for adjusting the thickness of the pressure-sensitive adhesive composition can be appropriately changed and implemented according to each coating method.

In the drying section 4, the support 11 coated with the pressure-sensitive adhesive composition is conveyed from the coating section 3, and when passing through the inside of the drying section 4, hot air is blown onto the support to heat it. The solvent and unreacted monomers are removed from the composition to form a pressure-sensitive adhesive layer. The drying unit 4 used in the present invention is the support 1
It is necessary that the floating method is such that hot air can be blown from above and below to dry. The drying device is not particularly limited as long as this condition is satisfied, but because of the wide selectivity of the drying conditions, the drying zone may be divided so that the hot air temperature can be controlled independently. preferable. Further, it is preferable that the number of the drying zones is large because more precise control of drying conditions can be performed.

In the laminating section 5, the release paper 10 having both sides releasable from the pressure-sensitive adhesive is attached to the support 11 heated and dried in the drying section 4 from above or below the support 11 (see FIG. 2 is pasted from the bottom). At this time, a non-adhesive roll such as a silicon roll is used as the roll that comes into contact with the exposed surface of the adhesive layer.

The double-sided pressure-sensitive adhesive tape take-up roll 25 winds up the support 11 bonded to the release paper at the bonding section 5, and thus the double-sided pressure-sensitive adhesive tape is manufactured.

The water-dispersed pressure-sensitive adhesive composition used in the present invention comprises an acrylic, natural rubber-based, synthetic rubber-based, or mixture thereof pressure-sensitive adhesive dispersed in water using an appropriate emulsifier or dispersant. Any thing can be used.

As the acrylic water-dispersed pressure-sensitive adhesive, (meth) acrylic acid ester, which is a main monomer, stabilizes emulsion particles, improves adhesiveness of the pressure-sensitive adhesive layer to a support, and adheres to an adherend. A functional group-containing vinyl-based monomer may be used in combination for the purpose of improving initial adhesiveness, and emulsion polymerization may be performed using a suitable emulsifier, a polymerization initiator, and the like.

The natural rubber and synthetic rubber adhesives used in the present invention include butyl rubber, butadiene rubber, styrene-butadiene rubber, isoprene rubber, neoprene, polyisobutylene, acrylonitrile-butadiene rubber, and styrene-isoprene block copolymer. Examples thereof include a polymer, a styrene-butadiene block copolymer, a styrene-ethylene-butadiene block copolymer, and the like.

The water-dispersible pressure-sensitive adhesive of the present invention also comprises
If necessary, various additives such as a cross-linking agent, a release modifier, a tackifier, a plasticizer, a softening agent, a filler, a pigment, a dye and an antiaging agent can be added.

In the present invention, the water-dispersible pressure-sensitive adhesive may have a polymer particle size of 0.1 to 3 μm, preferably 0.2 to 1 as long as it has good mechanical stability and coatability.
It is desirable to adjust to μm. Here, the particle size is 0.
If it is smaller than 1 μm, the viscosity of the water-dispersed pressure-sensitive adhesive may be increased, and if it is larger than 3 μm, the fusion property between particles may be decreased and the cohesive force may be decreased.

The solid content concentration of the water-dispersible pressure-sensitive adhesive of the present invention is not particularly limited, but is preferably 50% by weight or more in order to shorten the drying time after coating.

The thickness of the composition after drying is not particularly limited,
It can be over 1mm thick, but generally 50
It is 0 μm or less, preferably 3 to 300 μm, and particularly preferably about 5 to 200 μm.

The method for producing a double-sided pressure-sensitive adhesive tape of the present invention comprises applying a pressure-sensitive adhesive layer on both sides of a support by means of a coating unit, and removing water from the pressure-sensitive adhesive composition coated by a drying device. The method is characterized by the step of forming the pressure-sensitive adhesive layer, and for the other steps, a generally-used pressure-sensitive adhesive tape manufacturing method can be appropriately used.

[0037]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the examples. In the following, all parts mean parts by weight.

(Water-dispersed pressure-sensitive adhesive composition) 90 parts of butyl acrylate and 2-ethylhexyl acrylate were placed in a reaction vessel equipped with a cooling pipe, a nitrogen introducing pipe, a thermometer and a stirrer.
Parts, acrylic acid 3 parts, 3-methacryloxypropylmethyldiethoxysilane (KBE-502: manufactured by Shin-Etsu Silicone Co., Ltd.) 0.05 parts, 2,2′-azobis [2-
(5-Methyl-2-imidazolin-2-yl) propane]] dihydrochloride (initiator) 0.1 part, dodecanethiol (chain transfer agent) 0.05 part, and polyoxyethylene sodium lauryl sulfate (emulsifier) 2 Part of water 10
After addition to 0 part and emulsion polymerization, 10% by weight ammonium water was added to neutralize to obtain a water-dispersible acrylic pressure-sensitive adhesive having a solid content of 60% and an average particle diameter of 400 nm.

Example 1 The resulting water-dispersed acrylic pressure-sensitive adhesive was applied to a nonwoven fabric having a MD strength of 3.5 N / 15 mm and a wet elongation of 7% to give a total thickness of 150 μm after drying with a die coater. When the double-sided pressure-sensitive adhesive tape was obtained by coating with the coating machine shown in FIG. 2 and drying, no troubles during production such as breakage of the support or wrinkles were observed during the coating. .

Example 2 The resulting water-dispersed acrylic pressure-sensitive adhesive was applied to a nonwoven fabric having a wet strength in the MD direction of 27 N / 15 mm and a wet elongation of 12% so that the total thickness after drying with a die coater was 150 μm. When a double-sided pressure-sensitive adhesive tape was obtained by coating with the coating machine shown in FIG. 2 and drying, no troubles during production such as breakage of the support during the coating and wrinkles were observed.

Comparative Example 1 The obtained water-dispersed acrylic pressure-sensitive adhesive is shown in FIG. 2 so that the total thickness after drying with a die coater is 150 μm on a nonwoven fabric having a wet strength in the MD direction of 1.5 N / 15 mm. When coated with such a coating machine, there was a problem that the support was cut during coating.

[0042]

As is apparent from the above description, according to the invention described in claim 1, both sides of the support are coated by directly coating the support with the water-dispersible pressure-sensitive adhesive composition and drying it. The double-sided pressure-sensitive adhesive tape having the pressure-sensitive adhesive layer can be manufactured by a single coating and drying step. Therefore, two pressure-sensitive adhesive layers can be produced in one step, and the double-sided pressure-sensitive adhesive tape can be produced without using process paper, which is unnecessary for the final product like the conventional one, and thus the production cost can be reduced. It can be kept low.

According to the second aspect of the invention, when a nonwoven fabric is used as the support, the tensile strength (MD direction) when the nonwoven fabric is wet is 2.0 N / 15 mm or more. It can be applied and dried without breaking the body.

According to the invention of claim 3, when a nonwoven fabric is used as the support, the tensile strength (MD direction) of the nonwoven fabric when wet is 2.0 N / 15 mm or more, and the elongation when wet ( Since the MD direction) is 15% or less, the support can be coated and dried without being cut during the manufacturing process, and the support can be wound neatly without wrinkles.

According to the fourth aspect of the invention, the water-dispersed pressure-sensitive adhesive composition is directly applied to the upper and lower surfaces of the nonwoven fabric to produce a double-sided pressure-sensitive adhesive tape. Therefore, an appropriate pressure-sensitive adhesive composition layer can be provided on each of the upper surface and the lower surface, and the thickness thereof can be adjusted individually.

According to the invention of claim 5, the water-dispersed pressure-sensitive adhesive composition is applied using a die coater to produce a double-sided pressure-sensitive adhesive tape. Therefore, the water-dispersed pressure-sensitive adhesive composition can be applied to both surfaces of the support in a space-saving manner.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a conventional manufacturing apparatus, in which (a) shows a first-stage manufacturing process and (b) shows a second-stage manufacturing process.

FIG. 2 shows a schematic configuration of an entire double-sided tape manufacturing apparatus according to an embodiment of the present invention.

[Explanation of symbols]

10 Release paper 11 Support 20 Release paper supply roll 21 Support supply roll 25 Double-sided adhesive tape take-up roll 3 coating department 31 Supply tank 32 die coater 4 drying section 5 Laminating part

Claims (5)

[Claims] 1. A method for producing a double-sided pressure-sensitive adhesive tape, which comprises directly coating a water-dispersible pressure-sensitive adhesive composition on a support to produce a double-sided pressure-sensitive adhesive tape. 2. Tensile strength when wet as a support (MD direction)
The method for producing a double-sided pressure-sensitive adhesive tape according to claim 1, wherein a non-woven fabric having a viscosity of 2.0 N / 15 mm or more is used. 3. Tensile strength when wet as a support (MD direction)
Is 2.0 N / 15 mm or more, and a nonwoven fabric having a wet elongation (MD direction) of 15% or less is used. 4. The double-sided pressure-sensitive adhesive tape according to claim 1, wherein the double-sided pressure-sensitive adhesive tape is manufactured by directly coating the water-dispersed pressure-sensitive adhesive composition on the upper surface and the lower surface of the support. Manufacturing method. 5. The method for producing a double-sided pressure-sensitive adhesive tape according to claim 1, wherein the water-dispersed pressure-sensitive adhesive composition is applied using a die coater.