JPH07331198A - Pressure-sensitive adhesive tape and its production - Google Patents

Abstract

PURPOSE:To provide a pressure-sensitive adhesive tape which can be produced in good workability without any environmental problem caused by for example the use of a solvent and which is improved in heat-resistant holding power and reduced in releasability under a constant load by forming the pressure- sensitive layer from a pressure-sensitive adhesive composition of a higher degree of polymerization. CONSTITUTION:This tape is produced by applying an ultraviolet-curing pressure- sensitive adhesive composition 2x containing a 4-14C alkyl alcohol acrylate monomer, a monofunctional monomer copolymerizable therewith, a polyfunctional oligoacrylate of a molecular weight of 300 or above and a photopolymerization initiator to a base sheet such as a release sheet 3 and irradiating the applied composition 2x with ultraviolet rays in two stages in which the irradiation conditions in the second stage are more intensive than those in the first stage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a pressure-sensitive adhesive tape using a UV-curable pressure-sensitive adhesive composition.

[0002]

2. Description of the Related Art Conventionally, various types of double-sided pressure-sensitive adhesive tapes and single-sided pressure-sensitive adhesive tapes have been known as pressure-sensitive adhesive tapes, and acrylic pressure-sensitive adhesives are generally used as the pressure-sensitive adhesives. The following method is known as a method for producing an adhesive tape using an acrylic adhesive.

(1) An acrylate polymer is obtained by polymerizing an acrylate monomer by a solution polymerization method or an emulsion polymerization method, and a pressure-sensitive adhesive composition is prepared by adding a crosslinking agent or the like to the acrylate polymer liquid. Is applied to a support or release paper, and the solvent and water are scattered, and a crosslinking reaction is caused to cure the pressure-sensitive adhesive composition to obtain a double-sided pressure-sensitive adhesive tape.

(2) A method of producing an adhesive tape by a hot-melt method in which an acrylic polymer is melted and an adhesive is extruded into a tape shape using an extruder. According to this method, there is an advantage that the production equipment of the adhesive tape is relatively simple.

(3) A method of forming an adhesive for an adhesive tape by irradiating the adhesive composition with ultraviolet rays. As a method by such ultraviolet irradiation, a pressure-sensitive adhesive is obtained by irradiating an adhesive composition comprising (3-i) an acrylic ester monomer and a monomer component copolymerized therewith with ultraviolet rays to obtain a pressure-sensitive adhesive. Has been proposed for use as a pressure sensitive adhesive (Belgian Patent 675,420, 5/1
966). In addition, in the pressure-sensitive adhesive composition containing (3-ii) an acrylic monomer as a main component, a wavelength of 300 to 400 nm (300
There is known a method of irradiating an ultraviolet ray having a wavelength of nm or less of about 10% with an intensity of 7 mW / cm ² or less (USP 4,181,752). (3-iii) In the same method, a polyfunctional acrylic monomer is blended in the pressure-sensitive adhesive composition, and as this polyfunctional acrylic monomer, one having a carbon number between vinyls of 10 or less is used, and the amount used Is known to be 0.5 to 5 × 10 ⁻⁵ eq / g (USP 4,379,201).

[0006]

However, the pressure-sensitive adhesive tape produced by the method using the solution polymerization method or the emulsion polymerization method of the above method (1) has a low cohesive force at high temperature, so that the pressure-sensitive adhesive tape is heated to a high temperature. There is a problem that it cannot be used for a body. Further, regarding the manufacturing process, since multiple steps such as polymerization of monomers, preparation of a pressure-sensitive adhesive composition, application of a pressure-sensitive adhesive composition, and curing of a pressure-sensitive adhesive composition are required, the production facilities of the pressure-sensitive adhesive tape are complicated, There is also the problem of increased costs. Furthermore, in the curing process of the pressure-sensitive adhesive composition, a solvent and water are scattered, but this requires a large amount of heat energy, and also measures for environmental pollution such as solvent recovery and exhaust gas treatment are taken. There is a problem that it must be.

On the other hand, according to the method (2) of using the hot melt method, since no solvent is used, the problem as in method (1) does not occur, but the tackiness of the adhesive makes it difficult to handle and the workability is low. There is a problem of decrease. Further, if a pressure-sensitive adhesive having a high melting temperature is used, heat resistance can be improved, but if the temperature at the time of melt coating is increased accordingly, the pressure-sensitive adhesive causes thermal deterioration. Further, the base material coated with the pressure-sensitive adhesive is likely to be thermally deformed. Therefore, there is a limit in improving the heat resistance of the pressure-sensitive adhesive by using a pressure-sensitive adhesive having a high melting temperature. For this,
A method of improving heat resistance by irradiating an electron beam or ultraviolet rays after extruding the pressure-sensitive adhesive into a tape shape is also proposed,
When the holding power at high temperature is improved in this way, there arises a problem that the adhesive strength is lowered.

According to the method (3) of irradiating the acrylic pressure-sensitive adhesive composition with ultraviolet rays, it is possible to obtain a pressure-sensitive double-sided pressure-sensitive adhesive tape having a higher holding power at high temperature than the method (2). However, the wavelength of (3-i) is 300 to 400n
The pressure-sensitive adhesive obtained by irradiating the ultraviolet ray of m with an intensity of 7 mW / cm ² or less has a problem that the adhesiveness is low under a constant load after being once adhered to an adherend and the adhesion reliability is low. . Further, under this irradiation condition, it takes 10 minutes or more to complete the polymerization of the pressure-sensitive adhesive composition, resulting in an increase in manufacturing cost. Even when a polyfunctional acrylic monomer having 10 or less carbon atoms between vinyl groups is used in the pressure-sensitive adhesive composition of (3-ii), the problem of large peeling property under constant load cannot be solved. Furthermore, this polyfunctional acrylic monomer has a high vapor pressure, has a strong irritating odor, and causes skin disorders such as a rash, which causes a problem in the working environment.

Further, in any of the conventional methods of curing the pressure-sensitive adhesive composition by irradiation with ultraviolet rays, the monomer is mixed with 1
It is difficult to polymerize and cure at 00%. Therefore, the obtained adhesive tape has a problem that unpleasant odor due to unreacted monomer is strong. Further, the unreacted monomer vaporizes when exposed to a high temperature at the joint with the adherend, causing swelling and peeling, so that there is a problem of low adhesion reliability.

The present invention is intended to solve the above-mentioned problems of the prior art, and does not cause environmental problems due to the use of a solvent or the like, and is an ultraviolet-curable pressure-sensitive adhesive excellent in handleability. In producing a pressure-sensitive adhesive tape using the composition, increasing the degree of polymerization of the pressure-sensitive adhesive composition to increase the heat-resistant holding power of the pressure-sensitive adhesive, reduce the peelability under constant load, and thereby improve the adhesion reliability. It is an object.

[0011]

Means for Solving the Problems The present inventor has, as an adhesive composition, a specific acrylic acid ester monomer, a monofunctional monomer copolymerizable with the acrylic acid ester monomer, and a polyfunctional oligoacrylate having a molecular weight of 300 or more. It is possible to drastically increase the polymerization rate of the pressure-sensitive adhesive composition by using one containing the same and performing the ultraviolet irradiation in two stages of the first irradiation condition and the second irradiation condition having a higher irradiation intensity. Found. Further, using a specific pressure-sensitive adhesive composition and performing ultraviolet irradiation at two levels of irradiation intensity is not limited to the pressure-sensitive adhesive tape in which the release sheet and the pressure-sensitive adhesive are simply laminated, and the base in the pressure-sensitive adhesive layer. It has been found that the present invention is also effective in a mode in which a material is embedded and a mode in which a pressure-sensitive adhesive layer formed from such an ultraviolet-curable pressure-sensitive adhesive composition and a hot-melt adhesive layer are laminated, and the present invention is achieved. It came to completion.

That is, the present invention provides an acrylic ester monomer of an alkyl alcohol having 4 to 14 carbon atoms,
A pressure-sensitive adhesive composition containing a monofunctional monomer copolymerizable with the acrylic acid ester monomer, a polyfunctional oligoacrylate having a molecular weight of 300 or more, and a photopolymerization initiator is applied to a base sheet, and then ultraviolet irradiation is performed. Provided is a method for producing an adhesive tape, which is performed in two stages of an irradiation condition and a second irradiation condition having a higher irradiation intensity.

The present invention also provides an adhesive tape manufactured as described above.

The present invention will be described in detail below. In the drawings for explaining the present invention, the same reference numerals represent the same or equivalent constituent elements.

The UV-curable pressure-sensitive adhesive composition used in the pressure-sensitive adhesive tape of the present invention comprises an acrylic acid ester monomer of an alkyl alcohol having 4 to 14 carbon atoms, a monofunctional monomer copolymerizable with the acrylic acid ester monomer, It contains a polyfunctional oligoacrylate having a molecular weight of 300 or more and a photopolymerization initiator. Here, the acrylic acid ester monomer of an alkyl alcohol having 4 to 14 carbon atoms is an ester of a chain alkyl alcohol having 4 to 14 carbon atoms and acrylic acid, for example, butyl acrylate,
Isoamyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, isononyl acrylate,
Isooctyl acrylate, lauryl acrylate, decyl acrylate and the like can be used.

As the monofunctional monomer copolymerizable with such an acrylic acid ester monomer, a UV-polymerizable monomer is preferable, for example, acrylic acid, cyclic alkyl or acrylic acid ester of chain alkyl having 3 or less carbon atoms, and the like. Acrylic acid derivatives can be used, and more specifically, ethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfryl acrylate, isobonyl acrylate, ethoxy acrylate, butoxy acrylate, phenyl acrylate, Cyclohexyl acrylate or the like can be used. Also, oligoester acrylates such as nonylphenoxy polyethylene glycol acrylate and nonylphenoxy polypropylene glycol acrylate can be used.

Further, these monomers have carbon numbers of 4 to 1
When copolymerized with 4 alkyl acrylate monomers of alkyl alcohol, the glass transition point of the obtained copolymer rises. Therefore, the amount of these monomers used is such that the glass transition point of the copolymer is -15 ° C or higher. The range is preferably such that The glass transition point of the copolymer is -1
When the temperature is 5 ° C. or higher, the adhesive strength (tack) at room temperature decreases, which is not preferable.

The polyfunctional oligoacrylate having a molecular weight of 300 or more used in the present invention is an ester of two or more acrylic acids and a polyol and has a molecular weight of 300 or more. The polyfunctional oligoacrylate preferably has 10 or more carbon atoms between the vinyl groups of the two ester groups. Such polyfunctional oligoacrylates are used to increase the cohesive strength of adhesives at high temperatures.
A polyfunctional oligoacrylate having a molecular weight of less than 300 is not preferable because the distance between the cross-linking molecules becomes short, and the variation in the amount used greatly affects the cohesive force, making it difficult to control the cohesive force.

As the polyfunctional oligoacrylate having a molecular weight of 300 or more, for example, enneaethylene glycol diacrylate (NK ester A-400, manufactured by Shin-Nakamura Chemical Co., Ltd.), tetradecaethylene glycol diacrylate (NK ester A-600, Shin-Nakamura Chemical Co., Ltd.)
Polyalkylene glycol diacrylate such as ethylene oxide modified bisphenol A diacrylate (B
P-4EA, Kyoeisha Oil and Fat Chemical Co., Ltd., propylene oxide-modified bisphenol A diacrylate (B
P-4PA, Kyoeisha Oil & Fat Chemical Industry Co., Ltd., ethylene oxide-modified trimethylolpropane triacrylate (TMP-6EO-3A, Kyoeisha Oil & Fat Chemical Industry Co., Ltd.)
), Hydroxypivalic acid neopentyl glycol diacrylate (KAYARAD MANDA, manufactured by Nippon Kayaku Co., Ltd.) and its derivatives (KAYARAD HX).
-220, KAYARAD HX-620 and the like, manufactured by Nippon Kayaku Kogyo Co., Ltd. and the like can be used.

The polyfunctional oligoacrylate having a molecular weight of 300 or more is added to the ultraviolet-curable pressure-sensitive adhesive composition in an acrylic acid ester monomer of an alkyl alcohol having 4 to 14 carbon atoms and a copolymerizable acrylic acid ester monomer. Based on 100 parts by weight of the monofunctional monomer,
It is preferably 0.0001 to 0.002 mol.
If the amount is less than 0.0001 mol, the heat-resistant holding power of the pressure-sensitive adhesive tape tends to decrease, and if it is more than 0.002 mol, the tack of the pressure-sensitive adhesive tape tends to decrease.

The photopolymerization initiator is preferably an acetophenone-based or benzophenone-based one because it has a high polymerization rate and a polymerization rate of nearly 100%. As such a photopolymerization initiator, a commercially available one is used. can do. For example, 4-phenoxydicycloacetophenone 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, benzoin, benzoin methyl ether, Benzoin isobutyl ether, benzyl dimethyl ketal, or the like, or a mixture thereof can be used.

The amount of the photopolymerization initiator added to the ultraviolet-curable pressure-sensitive adhesive composition is an acrylic acid ester monomer of an alkyl alcohol having 4 to 14 carbon atoms, a monofunctional monomer copolymerizable with the acrylic acid ester monomer, and Total 100 of polyfunctional oligoacrylates with molecular weight of 300 or more
0.005 to 0.1 parts by weight is preferable with respect to parts by weight.

In addition, the ultraviolet-curable pressure-sensitive adhesive composition used in the present invention may contain a polymer compatible with the above-mentioned monomer component. That is, although the viscosity of the liquid of the composition containing the above-mentioned monomer component as a main component is as low as 2 to 20 centipoise, the viscosity of the composition can be increased to about 1000 to 10000 centipoise by dissolving the polymer. The workability can be improved. Examples of such polymers include acrylic rubber, styrene butadiene rubber, isobutylene rubber, styrene isobutylene block polymer, styrene butadiene block polymer, low molecular weight polyethylene, low molecular weight polyisoprene and the like. The amount of these polymers used is usually preferably 1 to 15% by weight in the ultraviolet-curable pressure-sensitive adhesive composition.

A filler may be added to the ultraviolet-curable pressure-sensitive adhesive composition used in the present invention in order to increase its viscosity. As the filler, for example, silica, aluminum hydroxide, barium sulfate, clay, talc, fine powder aerosol, glass bulb, glass beads, plastic microballoons, plastic fine powder and the like can be used. The amount of these fillers added is such that it does not interfere with the transmission of ultraviolet rays. In addition to the filler, a small amount of pigment or dye may be added for coloring.

The UV-curable pressure-sensitive adhesive composition comprising the above components becomes a pressure-sensitive pressure-sensitive adhesive when irradiated with ultraviolet rays.
In the method of the present invention, this ultraviolet-curable pressure-sensitive adhesive composition is not simply irradiated with ultraviolet rays, but after the ultraviolet-curable pressure-sensitive adhesive composition is applied to a substrate sheet, two-stage irradiation with different irradiation intensities is performed. Ultraviolet irradiation is performed to form a pressure-sensitive adhesive layer to manufacture a pressure-sensitive adhesive tape. In this case, as the base material sheet,
A release sheet used for a normal double-sided pressure-sensitive adhesive tape, or a hot-melt type adhesive film as described later can be used.

For example, in the case of producing an adhesive tape in which the release sheets 3 and 4 are provided on both sides of the adhesive 2 such as the double-sided adhesive tape 1 shown in FIG. 1, first, the double-sided release-treated fine paper or glassine is used. A UV-curable pressure-sensitive adhesive composition 2x having a thickness of 0.010 to 3.0 mm is placed on a release sheet 3 made of a paper such as paper or a polymer film subjected to release treatment on both sides.
And then apply a transparent release sheet 4 made of a polymer film such as PET that has been subjected to release treatment on one side to block oxygen in the air to make the layer thickness of the ultraviolet curable pressure sensitive adhesive composition 2x uniform. To do.

On the other hand, as an irradiation device under the first irradiation condition,
Weak light with a main wavelength of 352 nm (for example, light intensity 0.5 m
A straight tube type chemical lamp that emits w / cm ² )
A plurality of devices are arranged with an interval of about 100 mm or less, and an irradiation target is irradiated with light having an intensity of about 1.5 mw / cm ² or more. In the case of assembling such an irradiation device, it is preferable that the interval between the chemical lamps is made as small as possible in order to effectively increase the light intensity applied to the object to be irradiated.

With this irradiation device, the polymer film 4 is applied to the above-mentioned release sheet 3, the ultraviolet-curable pressure-sensitive adhesive composition 2x, and the release sheet 4 composed of the polymer film.
UV irradiation from the side. It is preferable that 80% or more of the monomers in the ultraviolet-curable pressure-sensitive adhesive composition 2x are polymerized by this irradiation.

Next, as an irradiation device under the second irradiation condition,
For example, a high-pressure mercury lamp having a main wavelength of 365 nm is used, and the light intensity is stronger than that in the first irradiation condition (for example, 30 mw / c).
Ultraviolet irradiation is performed so as to irradiate the object to be irradiated with m ² or more) to complete the polymerization. As the irradiation device under the second irradiation condition, it is preferable to use an ozoneless type lamp that does not generate ultraviolet rays in the low wavelength region of 200 nm or less. That is, ultraviolet rays in the low wavelength region are harmful because they make oxygen in the air ozone, and are also unfavorable because they accelerate the deterioration of the adhesive tape.

By performing the UV irradiation under the second irradiation condition different from the first irradiation condition, the total irradiation time required for completing the polymerization can be shortened. When the irradiation is continued only under the first irradiation condition, the tackiness of the obtained adhesive tape tends to be low. However, irradiation under the first irradiation condition is followed by irradiation under the second irradiation condition. As a result, tackiness can be improved.

When a white release paper is used as the release sheet 3 when the release sheet is coated with the UV-curable pressure-sensitive adhesive composition and irradiated with UV rays to produce a double-sided adhesive tape as described above, Release sheet 4 side) Adhesive 2
The heat-resistant holding force of the pressure-sensitive adhesive on the side of the release sheet 3 on the opposite side tends to be lower than the heat-resistant holding force of the above. If the heat-resistant holding powers of both surfaces of the pressure-sensitive adhesive 2 are different, it is necessary to consider the difference in the holding powers at the time of use, and the adhesive reliability is also lowered. Therefore, in the present invention, the color of the coating surface of the UV-curable pressure-sensitive adhesive composition of the release sheet 3 on the non-UV irradiation side is set to an achromatic lightness of 6 or less, or the chromatic color wheel has a blue to green hue ring. It is preferable that This allows
It is possible to eliminate the difference in heat-resistant holding power (heat-resistant cohesive force) between the ultraviolet irradiation side and the opposite side of the adhesive.

The achromatic lightness of 6 or less is a color in the range of light gray (lightness 6) to black (lightness 1). Dark gray has a lightness of 3-4. Further, when the chromatic hue circle is changed from blue to green, for example, the Munsell hue circle is 5 PB.
Blue-based colors of ~ 5BG are preferred.

As a method for making the coated surface of the ultraviolet ray-curable pressure-sensitive adhesive composition of the release sheet 3 such a color, the original color of the material such as paper constituting the release sheet 3 has such a color. May be used, or may be colored by printing or the like.

The method of the present invention can also be applied to an adhesive tape in which a base material is embedded in an adhesive layer. In this case, as the base material, for example, a material having low elasticity such as Japanese paper, non-woven fabric, plastic film (polyester film etc.), glass fiber, etc., or foam material such as urethane foam, chloroprene foam etc. is appropriately selected as necessary. However, it is preferable that the UV-curable pressure-sensitive adhesive composition is easily impregnated, and the nonwoven fabric is preferably a mixture of hemp and rayon. In particular, it is preferable to use a non-woven scrim.

FIG. 2 shows the non-woven scrim 5 in the adhesive layer 2.
FIG. 3 is a cross-sectional view of the double-sided pressure-sensitive adhesive tape of the present invention in which is embedded as a base material. As the non-woven scrim 5, as shown in FIG. 3, a longitudinal fiber (or fibrous film) 5a and a transverse fiber (or fibrous film) 5b are not woven, but an adhesive such as ethylene vinyl acetate is used. The pasted product is preferable.
As a result, the scrim is less likely to extend in the vertical or horizontal direction of the grid and is likely to extend in the diagonal direction. Also, the surface becomes smooth as if two films were stuck together. Therefore, various advantages can be enjoyed as follows.

That is, in general, in the case of adhering an adherend using an adhesive tape in which a base material is not embedded in an adhesive layer, if the adhesive tape once adhered is peeled off to correct the adhering position, Since the adhesive layer partially remains on the adherend and the adhesive tape extends, it becomes difficult to reuse the peeled adhesive tape. On the other hand, since the non-woven scrim is unlikely to stretch in the longitudinal or transverse directions of the grid, the adhesive tape using the non-woven scrim as a base material can be once peeled and reused. Therefore, it becomes easy to position the adherend.

Further, it is difficult to increase the thickness of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive tape in which the base material is not embedded in the pressure-sensitive adhesive layer, but by using the non-woven scrim as the base material, it is easily desired. It becomes possible to form the adhesive layer thicker than that.

Furthermore, in general, when a material having low elasticity such as Japanese paper, non-woven fabric or polyester is used as a base material of an adhesive tape, a rough surface having irregularities such as a sizing board or mortar is adhered. In that case, it becomes difficult to obtain a large adhesive strength. However, since the non-woven scrim has great elasticity in the diagonal direction of its grid, the adhesive tape using the non-woven scrim as a base material
Even when a rough surface having irregularities is used as the adherend, sufficient adhesive strength can be obtained.

Since the surface of the non-woven scrim is smooth,
Does not deteriorate the surface smoothness of the adhesive tape.

Nonwoven scrim fiber materials that can be preferably used in the present invention include synthetic fibers such as glass fiber, acrylic fiber, nylon fiber, polyester fiber, and the like.
Alternatively, natural fibers or the like can be used. Further, a polymer film such as polypropylene obtained by cutting these fibers into a slender shape can be used. Of these, glass fiber materials that transmit ultraviolet rays are preferable.

The size of the squares of the non-woven scrim is represented by the fiber thickness and the fiber interval (the number of fibers existing within 25 mm). Regarding the fiber interval, about 3 to 10 fibers are commercially available, but any of these can be used in the present invention. However, if the number of fibers present within 25 mm is too large, the meshes become fine and the elasticity is low, so that the adhesiveness when an uneven rough surface is used as the adherend becomes low. Further, if the number of fibers present within 25 mm is too small, the mesh becomes coarse, and it is difficult to obtain a sufficient effect even when the substrate is not used.

If the fiber thickness of the non-woven scrim is too thick, it becomes difficult to obtain an adhesive tape having a smooth surface.
It is preferable to use fibers having a denier of 00 or less or smooth film fibers having a thickness of 100 μm or less.

Further, as shown in FIG. 2, when the non-woven scrim 5 is provided in the pressure-sensitive adhesive layer 2, the position of the non-woven scrim 5 in the thickness direction of the pressure-sensitive adhesive layer 2 will be described. There is no particular limitation and it can be appropriately determined according to the surface irregularities of the adherend. For example, when the adherend has less surface irregularities, the pressure-sensitive adhesive layer 2 on the non-woven scrim 5 has a thickness of 5
It may be about μm. Generally, it is preferable to set the pressure-sensitive adhesive layer 2 at the substantially central portion.

The adhesive tape shown in FIG. 2 is, for example, as shown in FIG.
It can be manufactured according to the steps shown in.

First, as shown in FIG. 4 (a), the double-sided release sheet 3 is coated with the ultraviolet-curable adhesive composition 2x,
Next, the non-woven scrim 5 is superposed on the ultraviolet-curable pressure-sensitive adhesive composition layer 2x, the non-woven scrim 5 is impregnated with the pressure-sensitive adhesive composition, and the non-woven scrim 5 is irradiated with the ultraviolet-curable pressure-sensitive adhesive composition layer 2x.
It is embedded in the inside ((b) of the same figure). Further, the ultraviolet-transparent release sheet 4 subjected to the one-side release treatment is stacked and pressed by a roller (not shown) to adjust the ultraviolet-curable pressure-sensitive adhesive composition layer 2x to a predetermined thickness. Then, ultraviolet rays are irradiated from the side of the release sheet 4 by changing the irradiation intensity in two steps as described above ((c) in the figure), and the ultraviolet-curable pressure-sensitive adhesive composition 2x is cured into a pressure-sensitive adhesive. To get
Then, the release sheet 4 is peeled off and stored in a wound state ((d) in the same figure).

Further, in the method of the present invention, a pressure-sensitive adhesive layer obtained by curing the above-mentioned ultraviolet-curable adhesive composition layer, that is, a pressure-sensitive adhesive layer, and a hot-melt adhesive film are laminated. It can also be applied to the adhesive tape of the embodiment. As a result, an adherend that is difficult to bond with a pressure-sensitive adhesive but can be bonded with a hot-melt adhesive (for example, fluffy felt) and an adhesive that can be bonded well with a pressure-sensitive adhesive It becomes possible to adhere to the body (metal, plastic, etc.). As a specific embodiment of such an adhesive tape, as shown in FIG. 5A, an adhesive obtained by using a hot-melt adhesive film 6 in place of the release sheet 3 of the adhesive tape shown in FIG. An example of the tape or an adhesive tape obtained by using a hot-melt adhesive film 6 instead of the release sheet 3 of the adhesive tape shown in FIG. 5B is shown.

As the hot-melt type adhesive film 6, a commercially available product can be used. For example, an ethylene-vinyl acetate resin type, an ethylene-acrylic acid resin type, a polyester type, produced by a hot melt extrusion method, A film adhesive such as a polyamide type, a styrene-isoprene block polymer type, or a styrene-butadiene block polymer type can be used. Also, an epoxy-based epoxy produced by scattering a solvent from a solvent-type adhesive, an epoxy-
A film adhesive such as a phenol type adhesive, a chloroprene rubber type adhesive, or a nitrile rubber type adhesive can also be used.

[0048]

According to the present invention, since the pressure-sensitive adhesive of the pressure-sensitive adhesive tape is formed by using the ultraviolet-curable pressure-sensitive adhesive composition, environmental problems due to the use of a solvent or the like do not occur when forming the pressure-sensitive adhesive. Further, since the pressure-sensitive adhesive formed from this pressure-sensitive adhesive composition does not become unnecessarily sticky, the pressure-sensitive adhesive tape of the present invention has excellent handleability.

Furthermore, according to the present invention, since the ultraviolet irradiation for curing the ultraviolet-curable pressure-sensitive adhesive composition is performed in two stages of the first irradiation condition and the second irradiation condition having a higher irradiation intensity than that, It is possible to dramatically increase the polymerization rate of the pressure-sensitive adhesive composition. Therefore, it becomes possible to improve the heat resistance holding power of the pressure-sensitive adhesive and reduce the peeling property under a constant load, thereby improving the adhesion reliability.

In particular, in the method of the present invention, as the base sheet (release sheet) for coating the UV-curable pressure-sensitive adhesive composition, the color of the coated surface of the UV-curable pressure-sensitive adhesive composition is achromatic lightness 6 If the following is adopted or the chromatic hue circle is changed from blue to green, it is possible to eliminate the difference in heat-resistant holding power (heat-resistant cohesive force) between the UV-irradiated side surface and the opposite surface of the pressure-sensitive adhesive.

When the non-woven scrim is embedded in the pressure-sensitive adhesive layer, the elongation rate of the non-woven scrim in the fiber direction of the non-woven scrim can be greatly reduced. Therefore, the pressure-sensitive adhesive tape was temporarily adhered to the adherend. After that, the adhesive tape can be easily peeled off and reused. Therefore, when adhering the adhesive tape to the adherend, it is possible to favorably align them. Further, the elongation rate of the adhesive tape in the diagonal direction with respect to the fibers of the non-woven scrim is hardly reduced, and the original elongation rate of the adhesive agent is maintained. Therefore, even when a rough surface having irregularities is used as the adherend surface. It becomes possible to obtain high adhesive strength.

Further, when the pressure-sensitive adhesive tape of the present invention has a laminated mode of a pressure-sensitive adhesive formed of a UV-curable pressure-sensitive adhesive and a hot-melt type adhesive film, a pressure-sensitive adhesive formed of a UV-curable pressure-sensitive adhesive is difficult to adhere to. By adhering an adherend (for example, fluffy felt) and a hot melt type adhesive film, and adhering an adherend (metal, plastic, etc.) that can be favorably adhered with an adhesive, and an adhesive, It is possible to firmly bond different materials.

[0053]

EXAMPLES The present invention will be specifically described below based on examples.

Example 1 90 g of 2-ethylhexyl acrylate, 1 acrylic acid
To 100 g of the mixed monomer solution consisting of 0 g, 5 g of acrylic rubber (Toacron PS, manufactured by Toa Paint Co., Ltd.) was stirred and mixed in a container equipped with a stirrer for 48 hours to be dissolved. The solution was a viscous liquid with a viscosity of 1500 cps. The liquid has a molecular weight of 3 as a polyfunctional oligoacrylate.
12 of hydroxypivalic acid neopentyl glycol diacrylate (KAYARAD MANDA, manufactured by Nippon Kayaku Co., Ltd.) in an amount of 0.0005 mol (0.156 g) and 2-hydroxy 2- as an acetophenone-based photoinitiating polymerization agent.
Methyl-1-phenylpropan-1-one (Darocur,
0.02 g (manufactured by Merck & Co., Inc.) was added to obtain an ultraviolet-curable pressure-sensitive adhesive composition.

Next, a double-sided pressure-sensitive adhesive tape was manufactured as follows using the obtained ultraviolet-curable pressure-sensitive adhesive composition.

First, a UV-curable pressure-sensitive adhesive composition was applied to a release paper obtained by subjecting both sides of blue-green fine paper showing 5BG in Munsell hue circle to release treatment with silicone to a thickness of about 0.06 mm. . Next, a transparent polyester film having a thickness of 50 μm, one surface of which was subjected to a release treatment with silicone, was placed thereon, and the thickness was adjusted so that the pressure-sensitive adhesive composition layer had a thickness of 0.06 mm. After that, a fluorescent lamp for trapping insects (main wavelength 352 nm, 0.44 mW / cm ² ) was used for 60 m.
The UV irradiation is performed from the transparent polyester film side of the irradiated object in an irradiation furnace arranged at m intervals so that the irradiated object can be irradiated with ultraviolet light of about 2.00 mW / cm ² from a height of 200 mm. Went for a second. Furthermore, a high pressure mercury lamp (main wavelength 365 nm, output 80 mW / cm
^{Using 2} ), UV irradiation was performed for 30 seconds at an irradiation intensity of 35.5 mW / cm ² to sufficiently cure the UV-curable pressure-sensitive adhesive composition to obtain a double-sided pressure-sensitive adhesive tape. Then, the transparent polyester film of the double-sided adhesive tape was peeled off to obtain a transfer type double-sided adhesive tape having a thickness of 0.057 mm.

The obtained double-sided pressure-sensitive adhesive tape was evaluated as follows. (i) Polymerization rate About 0.5 g of a pressure-sensitive adhesive cured by ultraviolet irradiation is precisely weighed,
The sample was left at 120 ° C. and 5 mmHg for 2 hours to volatilize volatile components, and weighed again to determine the weight reduction amount. The polymerization rate was calculated by the following equation, using this weight reduction amount as an unpolymerized monomer.

Polymerization rate% = [1- (weight reduction amount / weight of pressure-sensitive adhesive before volatilization treatment)] × 100 As a result, the polymerization rate of the pressure-sensitive adhesive after irradiation with the insect trap fluorescent lamp was 88.5%, The polymerization rate of the pressure-sensitive adhesive after irradiation with the high-pressure mercury lamp was 99.9%. (ii) Heat-resistant holding power The heat-resistant holding power was measured according to the method for measuring the holding power of JIS Z 0237. In this case, as the adherend, a stainless steel plate with a thickness of 2 mm and a thickness of 0.005 m, which were polished with No. 280 water-resistant abrasive paper
m aluminum foil is used, and the adhesion area is 25 mm x 2
It was set to 5 mm. Then, after adhering these with a double-sided adhesive tape, a load of 1 kgf was vertically applied and left at 180 ° C. for 1 hour, and the amount of deviation of the adhered portion after standing was measured.

As a result, there was no deviation. (iii) Peeling resistance under constant load As adherend, thickness 2 polished with No. 280 water resistant abrasive paper
A stainless steel plate having a thickness of 30 mm, a width of 30 mm and a length of 150 mm and an aluminum foil having a thickness of 0.05 mm were used. And
The double-sided adhesive tape was cut into a width of 20 mm and a length of 100 mm, and the stainless steel plate and the aluminum foil were bonded. Fix the stainless steel plate horizontally, and attach it to the end of the aluminum foil without adhesive so that it can be peeled off in the 90 degree direction.
A load of 00 g was applied and kept vertically, the whole was placed in an atmosphere of 50 ° C., and after 24 hours, the length of progress of peeling was determined.

As a result, the peeled length after 24 hours was 0.5 mm. (iv) Swelling and peeling of the adhesive part, 2 mm thick and 50 m wide polished with No. 280 water resistant abrasive paper
m, length 150 mm stainless steel plate and thickness 0.025 m
The polyimide film of m was attached so as not to entrap air. Then, it was left in an oven at 200 ° C. for 1 hour, and then the presence or absence of swelling or peeling of the adhesive part was observed.

As a result, neither swelling nor peeling occurred.

Examples 2 to 4 Hydroxypivalic acid neopentyl glycol diacrylate having a molecular weight of 312, which was used as a polyfunctional oligoacrylate in the production of the double-sided pressure-sensitive adhesive tape of Example 1, (KAYARAD MANDA, manufactured by Nippon Kayaku Co., Ltd.) Example 1 was repeated except that the compounding amount of was changed as shown in Table 1 to produce a double-sided adhesive tape. Then, in the same manner as in Example 1, the polymerization rate (after irradiation with a mercury lamp), heat resistance, peeling resistance under constant load, and swelling or peeling of the adhesive portion were evaluated. The results are shown in Table 1. In addition, Table 1 shows Example 1
The results are also shown.

Comparative Example 1 2-Ethylhexyl acrylate 93 mol%, Acrylic acid 5 mol%, 2-Hydroxyethyl acrylate 2 mol%
Benzoyl peroxide 3 in 1000 g of mixed monomer consisting of
g was dissolved. In a 3 liter 3-neck separable flask in which a cooling condenser and a stirrer were set, 400 g of a mixed monomer in which benzoyl peroxide was dissolved and 600 g of ethyl acetate were put, and the atmosphere was sufficiently replaced with nitrogen, and the temperature was gradually raised. Refluxed. The reflux temperature was 76 ° C. Refluxing was continued for 1 hour, and the remaining mixed monomers were added over 2 hours. Then, the mixture was refluxed for 3 hours, and then ethyl acetate 27
30 g was added to obtain a viscous acrylic polymer solution having a viscosity of 3200 cps. Next, this acrylic polymer solution 1
Xylene resin (made by Nippon Carbide Co., H-8
0) and 100 g of a curing agent (Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) were added and mixed sufficiently to obtain an adhesive solution. The solid content of this adhesive solution was 29.5%.

Next, the obtained pressure-sensitive adhesive solution was applied to a release paper similar to that in Example 1 to a thickness of about 0.2 mm, the solvent was scattered at 130 ° C. for 5 minutes, and a transfer having a thickness of 0.058 mm was performed. A mold double-sided adhesive tape was manufactured.

The degree of polymerization of the pressure-sensitive adhesive of the obtained double-sided pressure-sensitive adhesive tape, the heat-resistant holding power, the constant load peeling resistance, and the swelling and peeling of the adhesive portion were evaluated in the same manner as in Example 1. The results are shown in Table 1. As shown in this table, the weight reduction amount in the evaluation of the polymerization rate was 2.75%, which was 97.3 in terms of the conversion rate.
%Met. Further, the heat-resistant holding power cannot withstand a temperature of 100 ° C., and the peel length in the evaluation of constant load peel resistance is 50.
It was mm. Further, the adhesion part was swollen.

Comparative Example 2 In the production of the double-sided pressure-sensitive adhesive tape of Example 1, Example 1 was repeated except that the polyfunctional oligoacrylate was not used to prepare a solventless UV-curable pressure-sensitive adhesive composition, which was used. To produce a double-sided adhesive tape. Then, the polymerization rate (after irradiation with a mercury lamp) and heat resistance of the obtained double-sided pressure-sensitive adhesive tape were evaluated.

The results are shown in Table 1. As shown in this table, the polymerization rate was 99.9%, but with respect to the heat-resistant holding power, a load of 1 kgf could not be held at 180 ° C. at all,
It immediately fell.

Comparative Example 3 In the production of the double-sided pressure-sensitive adhesive tape of Example 1, Example 1 was repeated except that UV irradiation was carried out for 300 seconds only in an irradiation furnace using a fluorescent lamp for trapping insects, and irradiation with a high pressure mercury lamp was not carried out. , Double-sided adhesive tape was manufactured. Then, the obtained double-sided pressure-sensitive adhesive tape was evaluated for polymerization rate, heat-resistant holding power, constant load peeling resistance, and swelling or peeling of the adhesive portion in the same manner as in Example 1. The results are shown in Table 1. As shown in Table 1, the polymerization rate was 99.9% even after 5 times irradiation. In addition, the tackiness of the adhesive tape by touching the finger is determined in Example 1.
It was lower than the adhesive tape.

Comparative Example 4 In the production of the double-sided adhesive tape of Example 1, Example 1 was repeated except that the irradiation of ultraviolet rays was carried out for 120 seconds only by the high pressure mercury lamp without using a fluorescent lamp for trapping insects. Manufactured. Then, the obtained double-sided pressure-sensitive adhesive tape was evaluated for polymerization rate, heat-resistant holding power, constant load peeling resistance, and swelling or peeling of the adhesive portion in the same manner as in Example 1. As a result, the degree of polymerization reached 99.9%, but the heat resistance was poor.

[0070]

[Table 1] By comparing the results of Examples 1 and 2 and Comparative Examples 1 and 2, the pressure-sensitive adhesive tape using the ultraviolet-curable pressure-sensitive adhesive composition of the present invention has a high polymerization rate, heat resistance and constant load peeling resistance. It can be seen that the adhesiveness is excellent, and there is no swelling or peeling of the adhesive portion, and that the adhesive has high adhesion reliability.

Further, by comparing the results of Examples 1 and 2 and Comparative Examples 3 and 4, the ultraviolet irradiation was performed in two stages of the first irradiation condition and the second irradiation condition having a higher irradiation intensity. By carrying out, it was confirmed that the degree of polymerization of the pressure-sensitive adhesive can be increased, and the heat-resistant holding force and the peeling resistance under a constant load can be greatly improved.

Example 5 The production of the double-sided pressure-sensitive adhesive tape of Example 1 was repeated except that an achromatic release paper having a brightness of 0 (black) was used in place of the blue-green release paper showing 5BG in the Munsell hue circle. Example 1 was repeated to produce a double-sided adhesive tape. The heat-resistant holding power of the obtained double-sided pressure-sensitive adhesive tape was evaluated as follows.

The measurement was carried out according to the method for measuring the holding power of JIS Z 0237. In this case, as the adherend, a stainless steel plate having a thickness of 2 mm and an aluminum foil having a thickness of 0.005 mm polished with No. 280 water resistant polishing paper were used. In this case, as the adhesion area between the adhesive and the adherend, as shown in FIG. 6, the contact area of the adhesive 2 with the stainless plate S is 25 mm × 25 mm, and the contact area of the adhesive 2 with the aluminum foil A is Has a width of 25 mm and a length of 50 mm or more to reduce the contact area of the stainless plate S. In addition, two kinds of adhesion were performed, in which the back side (black release paper side) of the double-sided adhesive tape was adhered to the stainless steel plate and the front side (irradiation side) was adhered to the stainless steel plate. When the back side (black release paper side) of the double-sided adhesive tape is adhered to the stainless steel plate,
For each of the case where the front side (irradiation side) was adhered to the stainless steel plate, a load of 1 kgf was applied vertically after the adhesion and 1
It was left at 80 ° C. for 1 hour, and the size of the deviation of the adhesive portion after standing was measured.

As a result, as shown in Table 2, it was found that the deviation was 0.1 mm or less in all cases, and the heat-resistant holding power was excellent. In Table 2, the front side (irradiation side) or the back side (release paper side) represents the surface of the pressure-sensitive adhesive adhered to the stainless steel plate.

Examples 6 to 14 Example 1 was repeated except that in the production of the double-sided pressure-sensitive adhesive tape of Example 1, instead of the blue-green release paper of Munsell hue ring 5BG, the release paper of the colors shown in Table 2 was used. Repeatedly, a double-sided adhesive tape was manufactured. The heat-resistant holding power of the obtained double-sided pressure-sensitive adhesive tape was evaluated in the same manner as in Example 5. The results are shown in Table 2.

[0076]

[Table 2] From the results of Table 2, among the examples of the pressure-sensitive adhesive tape of the present invention, it is preferable that the color of the coated surface of the release paper has an achromatic lightness of 6 or less, or that the chromatic color wheel has a blue to green hue. I understand.

Example 15 A UV-curable pressure-sensitive adhesive composition was prepared in the same manner as in Example 1, and the obtained UV-curable pressure-sensitive adhesive composition was used to produce a double-sided pressure-sensitive adhesive tape as follows.

First, a UV-curable pressure-sensitive adhesive composition was applied to a release paper obtained by subjecting both sides of a high-quality paper, which had a blue color of 5BG with Munsell hue circle, to a release treatment with silicone to a thickness of about 0.7 mm. Then, a non-woven scrim (glass fiber, fiber thickness of about 600 denier, scrim grid 5 mm square) was applied on the applied ultraviolet-curable adhesive composition (adhesive scrim KC0505BEV2, manufactured by Polymer Processing Laboratory Co., Ltd.). ) Was repeated. This caused the pressure-sensitive adhesive composition to seep onto the non-woven scrim.

Then, a transparent polyester film having a thickness of 50 μm, which was peeled off on one side with silicone, was placed thereon, and the thickness was adjusted so that the pressure-sensitive adhesive composition layer had a thickness of 0.7 mm. After that, an insect trap fluorescent lamp (main wavelength 352)
nm, 0.44 mW / cm ² ) at 60 mm intervals,
Approximately 2.00 mW from a height of 200 mm with respect to the irradiated object
Ultraviolet irradiation was performed for 60 seconds from the transparent polyester film side of the irradiation target in an irradiation furnace capable of performing ultraviolet irradiation of / cm ² . Further, using a high pressure mercury lamp (output 80 mW / cm ² ), irradiation intensity of 35.
Ultraviolet irradiation at 5 mW / cm ² was performed for 30 seconds to sufficiently cure the ultraviolet curable pressure-sensitive adhesive composition to form an adhesive layer.

Then, the transparent polyester film was peeled off to obtain a double-sided adhesive tape. The obtained double-sided pressure-sensitive adhesive tape was free of bubbles and had a smooth surface. In addition, the thickness of the digital micrometer (μma
te, manufactured by Sony Magnescale Co., Ltd., and was 0.695 to 0.705 mm.

Further, the obtained double-sided pressure-sensitive adhesive tape was evaluated as follows.

(I) Adhesive strength to rough surface having irregularities A wall material was used as an adherend. This wall material was a sizing board spray-coated with an acrylic paint, and the size of the protrusion was 1 to 7 mm in diameter and 0.5 to 1 mm in height. This wall material was cut into a width of 30 mm and a length of 200 mm.

A double-sided adhesive tape having a width of 20 mm and a length of 100
It was cut into mm and lightly attached to a wall material. Also, width 30
The aluminum foil having a thickness of 50 μm and cut into a length of 200 mm and a length of 200 mm was used as a backing material, and the roller was reciprocated once with a load of about 4 kg to adhere the foil.

After adhering, it was left at 23 ° C. for 48 hours, and the 90 ° peel adhesive strength was measured at a peeling speed of 300 mm / min. As a result, the pressure-sensitive adhesive was firmly adhered to the wall material, the surface of the wall material was destroyed, and the pressure-sensitive adhesive layer partially caused cohesive failure. The adhesive strength was 3.5 kgf / cm.

(Ii) Elongation rate of double-sided pressure-sensitive adhesive tape Assuming that the double-sided pressure-sensitive adhesive tape was rolled, the double-sided pressure-sensitive adhesive tape was cut into pieces having a width of 10 mm parallel to the longitudinal direction of the non-woven scrim. Two fibers were embedded in the longitudinal direction in the shredded double-sided adhesive tape.

This double-sided pressure-sensitive adhesive tape was cut into a length of about 100 mm, and the elongation was measured at a pulling speed of 20 mm / min. As a result, the elongation was 0 until the fiber was cut.

Further, the double-sided pressure-sensitive adhesive tape was cut into a width of 10 mm in an oblique direction (45 °) with respect to the fibers in the longitudinal direction of the non-woven scrim, and the elongation rate was measured. As a result, the tensile strength due to the non-woven scrim fiber did not occur, and the pressure-sensitive adhesive layer expanded immediately after the start of tension. The elongation rate was 850%.

As described above, this double-sided pressure-sensitive adhesive tape does not extend in the direction parallel to the fibers of the non-woven scrim, but extends well in the diagonal direction, and the fibers of the non-woven scrim do not restrain the elongation of the pressure-sensitive adhesive layer. Recognize. Further, from this, it is understood that this adhesive tape has good adhesion to an adherend having irregularities.

(Iii) Removability at the time of sticking A double-sided pressure-sensitive adhesive tape (roll-shaped) with release paper (polyester film) cut into pieces 10 mm in width parallel to the longitudinal fibers of the non-woven scrim is about 1 m long. Lightly stuck to the acrylic plate. After that, when peeled off with release paper,
The pressure-sensitive adhesive tape could be peeled off without being stretched while being in close contact with the release paper. Then, it was able to be satisfactorily attached to the acrylic plate again.

Examples 16 to 26 Double-sided pressure-sensitive adhesive tapes were produced by repeating Example 15 except that the fiber material, the fiber thickness, the size of the mesh of the non-woven scrim were changed, and the thickness of the pressure-sensitive adhesive layer was changed. . Then, the obtained double-sided pressure-sensitive adhesive tape was evaluated in the same manner as in Example 15.
The results are shown in Table 3. In addition, in Table 3, Example 15
The results are also shown.

[0091]

[Table 3] From Table 3, it can be seen that among the pressure-sensitive adhesive tapes of the present invention, the one in which the non-woven scrim is embedded in the adhesive layer does not extend in the longitudinal direction of the fibers of the non-woven scrim and thus has removability. Further, such an adhesive tape does not extend in the longitudinal direction of the fibers of the non-woven scrim, but extends in an oblique direction,
Therefore, it can be seen that it is suitable for bonding to a rough surface having irregularities.

Comparative Example 5 An adhesive solution was prepared in the same manner as in Comparative Example 1. This pressure-sensitive adhesive solution was applied onto a release paper so as to have a thickness of about 1 mm, and a non-woven scrim having a grid size of 5 mm was impregnated thereon. In this case, the adhesive solution was framed so as not to flow around. Then, by leaving it at 23 ° C. for about 1 hour, the solvent ethyl acetate was slowly scattered. Then, it dried in a 100 degreeC drying oven, and manufactured the double-sided adhesive tape.

The obtained double-sided pressure-sensitive adhesive tape had a thickness of 0.20.
The thickness was not constant at .about.0.28 mm, and the traces of bubbles generated due to foaming during drying of the solvent were present on the entire surface. Therefore, even if a non-woven scrim is used in the pressure-sensitive adhesive layer, when the pressure-sensitive adhesive layer is formed without using the UV-curable pressure-sensitive adhesive composition used in the present invention, a pressure-sensitive adhesive tape having satisfactory appearance can be obtained. You can see that you cannot get it.

Example 27 A UV-curable pressure-sensitive adhesive composition was prepared in the same manner as in Example 1, and the obtained UV-curable pressure-sensitive adhesive composition was used to produce a double-sided pressure-sensitive adhesive tape as follows.

First, an ultraviolet-curable pressure-sensitive adhesive composition was applied on a polyester hot-melt adhesive film (PFS-170H, manufactured by Toagosei Co., Ltd.) having a thickness of 0.15 mm so that the thickness was about 0.15 mm. Was applied to. On top of that, thickness 0.
A 02 mm rayon non-woven fabric is overlaid and impregnated with the pressure-sensitive adhesive composition, and a transparent polyester film having a thickness of 50 μm, which has been peeled with silicone, is overlaid.
The thickness was adjusted to be 15 mm. After that, as in Example 1, a fluorescent lamp for trapping insects (main wavelength 352 nm, 0.
44 mW / cm ² ) are arranged at intervals of 60 mm, and UV irradiation is performed from the transparent polyester film side in an irradiation furnace that is capable of performing UV irradiation of about 2.00 mW / cm ² from a height of 200 mm to the irradiation target. For 60 seconds.
In addition, a high-pressure mercury lamp (output 80 mW / c
m ² ), UV irradiation was performed for 30 seconds at an irradiation intensity of 35.5 mW / cm ² to sufficiently cure the UV-curable pressure-sensitive adhesive composition to form a pressure-sensitive adhesive layer. As a result, an adhesive tape having a thickness of 0.295 mm was obtained.

The pressure-sensitive adhesive tape thus obtained was evaluated as follows.

(I) Heat-resistant holding power The heat-resistant holding power was measured according to the method of measuring the holding power of JIS Z 0237. In this case, as the adherend, a 2 mm-thick stainless steel plate polished with No. 280 water-resistant abrasive paper and a wool-made thickness 3
mm felt (2000H, manufactured by Kaji Felt Co., Ltd.) was prepared. Then, first, the adhesion between the felt and the hot melt adhesive film is performed at 150 ° C. for 15 seconds at 5 kgf / c.
m ² and then the adhesion between the stainless steel plate and the adhesive layer,
It was performed at 23 ° C. and a roll pressure of 4 kgf / cm ² . The adhesion area at this time was 25 mm × 25 mm in both cases.

After bonding, a load of 1 kgf is applied vertically to
It was left to stand at 00 ° C. for 24 hours, and the size of the displacement of the adhesive portion after the stand was measured. As a result, there was no gap.

(Ii) Peeling resistance under constant load As an adherend, a thickness of 2 with a No. 280 water-resistant abrasive paper
mm, a width of 30 mm, a length of 150 mm, and a 0.05 mm thick aluminum foil were prepared. And
The adhesive tape is cut into a width of 20 mm and a length of 100 mm, and first, the aluminum foil and the hot-melt adhesive film are bonded at 150 ° C. for 15 seconds at 5 kgf / cm ² ,
Next, the stainless steel plate and the pressure-sensitive adhesive layer were bonded to each other at 23 ° C. and a roll pressure of 4 kgf / cm ² with the length of the bonded portion being 70 mm.
I went there.

After adhering, the stainless steel plate was fixed horizontally, and
Apply a load of 500g to the end of the aluminum foil to keep it vertical so that peeling in the direction of 0 degrees is performed, and the whole is kept at 50 ° C.
After 24 hours, the length of progress of peeling was determined.

As a result, the peeled length after 24 hours was 0.5 mm.

Example 28 In the production of the pressure-sensitive adhesive tape of Example 27, the thickness of the pressure-sensitive adhesive layer formed from the ultraviolet-curable pressure-sensitive adhesive composition was 0.06 m.
Example 27 was repeated except that m was set. Then, the heat-resistant holding power and the peeling resistance under a constant load of the obtained adhesive tape were evaluated in the same manner as in Example 27. As a result, no deviation occurred in the measurement of heat-resistant holding force, and the peeling length under constant load was 0 mm.

Examples 29 to 31 Hydroxypivalic acid neopentyl glycol diacrylate (KAYARAD MANDA, manufactured by Nippon Kayaku Co., Ltd.) having a molecular weight of 312, which was used as a polyfunctional oligoacrylate in the production of the adhesive tape of Example 27, was used. Example 27 was repeated to produce an adhesive tape except that the compounding amount was changed as shown in Table 4. Then, the heat resistance holding force and the peeling resistance under a constant load were evaluated in the same manner as in Example 27. The results are shown in Table 4. In Table 4, Example 27 was used.
The results are also shown.

[0104]

[Table 4] Comparative Example 6 A pressure-sensitive adhesive solution was prepared in the same manner as in Comparative Example 1. This adhesive solution is applied on a release paper with a thickness of 0.35 mm, and 1
The solvent was scattered at 30 ° C. for 5 minutes to obtain a double-sided adhesive tape having a thickness of 0.06 mm.

Then, the thickness used in Example 27 was 0.15.
mm polyester hot melt adhesive film (P
FS-170H, manufactured by Toagosei Co., Ltd. and the obtained double-sided adhesive tape were laminated at 50 ° C. to obtain an adhesive tape.

The heat-resistant holding power of the obtained adhesive tape,
The peel resistance under a constant load was evaluated in the same manner as in Example 27. As a result, in the evaluation of heat-resistant holding power, the deviation of the bonded portion became 25 mm or more after 2 hours, and it could not be held and dropped. Further, in the evaluation of the peel resistance under a constant load, the peel length after 24 hours was 70 mm or more and 5
A load of 00 g dropped.

[0107]

According to the present invention, an adhesive tape can be manufactured with good workability without causing environmental problems due to the use of a solvent or the like. In addition, since the degree of polymerization of the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape can be increased, the heat-resistant holding power can be increased, and the peelability under constant load can be reduced. .

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an adhesive tape of the present invention.

FIG. 2 is a cross-sectional view of another aspect of the adhesive tape of the present invention.

FIG. 3 is a plan view of a non-woven scrim.

FIG. 4 is an explanatory diagram of a method for producing an adhesive tape of the present invention.

FIG. 5 is a cross-sectional view of another aspect of the adhesive tape of the present invention.

FIG. 6 is an explanatory diagram of a method for measuring heat resistant holding power.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Double-sided adhesive tape 2 Adhesive (adhesive layer) 2x Adhesive composition 3 Release sheet 4 Release sheet 5 Non-woven scrim 5a, 5b Fiber of non-woven scrim 6 Hot melt type adhesive film

Claims (9)

[Claims] 1. An acrylic ester monomer of an alkyl alcohol having 4 to 14 carbon atoms, a monofunctional monomer copolymerizable with the acrylic ester monomer, and a molecular weight of 30.
An ultraviolet-curable pressure-sensitive adhesive composition containing 0 or more polyfunctional oligoacrylate and a photopolymerization initiator is applied to a substrate sheet, and then ultraviolet irradiation is performed under the first irradiation condition and irradiation intensity higher than that. A method for producing an adhesive tape, characterized in that it is carried out in two stages of strong second irradiation conditions. 2. The ultraviolet-curable pressure-sensitive adhesive composition has a molecular weight of 3
A polyfunctional oligoacrylate of 00 or more has 4 to 4 carbon atoms.
0.000 based on 100 parts by weight of a total of 14 acrylic acid acrylate monomers of alkyl alcohol and monofunctional monomers copolymerizable with the acrylate ester monomers.
The method for producing an adhesive tape according to claim 1, wherein the adhesive tape is contained in an amount of 1 to 0.002 mol. 3. The ultraviolet-curable pressure-sensitive adhesive composition, wherein the photopolymerization initiator is an acrylic acid ester monomer of an alkyl alcohol having 4 to 14 carbon atoms, a monofunctional monomer copolymerizable with the acrylic acid ester monomer, And molecular weight 300
The method for producing the pressure-sensitive adhesive tape according to claim 1, wherein the polyfunctional oligoacrylate is contained in an amount of 0.005 to 0.1 parts by weight based on 100 parts by weight in total. 4. The method for producing an adhesive tape according to claim 1, wherein the ultraviolet irradiation under the first irradiation condition is performed until the polymerization degree of the ultraviolet curable adhesive composition reaches 80% or more. 5. The ultraviolet irradiation under the first irradiation condition is carried out by using a lamp having a main wavelength of 352 nm, and the ultraviolet irradiation under the second irradiation condition is carried out by using a lamp having a main wavelength of 365 nm. The method for producing the adhesive tape according to any one of claims. 6. When performing ultraviolet irradiation from above the ultraviolet-curable pressure-sensitive adhesive composition on the base sheet, the color of the coated surface of the ultraviolet-curable pressure-sensitive adhesive composition on the base sheet is set to an achromatic lightness of 6 or less. Or the chromatic hue circle is changed from blue to green, The method for producing an adhesive tape according to claim 1. 7. The non-woven scrim is embedded in the UV-curable pressure-sensitive adhesive composition layer after the UV-curable pressure-sensitive adhesive composition is applied to the substrate sheet, and then the UV-irradiation is performed. The method for producing the adhesive tape according to. 8. The method for producing a pressure-sensitive adhesive tape according to claim 1, wherein a hot-melt type adhesive film is used as a substrate sheet on which the ultraviolet-curable pressure-sensitive adhesive composition is applied. 9. An adhesive tape produced by the method according to claim 1.