JPH0625625A - Production of double-sided tape - Google Patents

Abstract

PURPOSE:To provide a method for producing a double-sided tape which does not cause reduction of the self-adhesive performance of its self-adhesive faces in the production of the tape by photopolymerization in an inert gas atmosphere, and to provide a method for producing a stably thick double-sided tape with no release base material. CONSTITUTION:Two pieces of a release base material 10 with a releasable surface are each coated with a photo-reactive composition 11 composed primarily of an acrylic ester. Then, upto 98wt.% of all the monomers in the composition 11 is partially polymerized through light irradiation 3 to prepare partially polymerized tapes 12. A soft base material 13 is held between the partially polymerized tapes 12 and the tapes are pasted thereto. After the completion of the polymerization, the two sheets of the release base material 10 are peeled off to leave a double-sided tape 14 itself, which is rolled up exclusively.

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 double-sided tape using a photoreactive composition containing an acrylic ester as a main component.

[0002]

2. Description of the Related Art Generally, since an acrylic pressure-sensitive adhesive is mainly composed of an acrylic polymer, it has light resistance, weather resistance, and
Acrylic adhesive tape that has excellent oil resistance, etc.
It is widely used because of its excellent adhesive performance such as adhesive strength and cohesive strength, and aging resistance such as heat resistance and weather resistance.

For example, an acrylic pressure-sensitive adhesive tape, which is a typical example of these viscoelastic products, first comprises a vinyl-based monomer containing an acrylate-based monomer such as an alkyl acrylate and / or a methacrylic acid ester as a main component in an organic solvent. It was manufactured by solution polymerization to obtain a pressure-sensitive adhesive solution, or emulsion polymerization in an aqueous system to form an emulsion, which was coated or impregnated on a substrate and dried by heating.

However, in the above manufacturing method, when an adhesive solution is used, much energy is required to dry the adhesive solution applied or impregnated on the substrate at a high temperature, and air pollution by the solvent is required. To prevent this, a large-scale recovery device is required. Moreover, since the solvent easily catches fire, a sufficient safety device is required to maintain safety. Especially recently, there is a problem that some solvents are inevitably released into the atmosphere from the viewpoint of global level environmental protection.
This method tends to be abolished.

On the other hand, when an emulsion is used, more energy is required to evaporate the water than when a solvent is used, and in terms of performance, the emulsifier mixed during polymerization lowers the water resistance. Further, since only a small amount of the water-soluble monomer can be used, the monomer species are limited, and there is a disadvantage that the ability to respond to various needs required for the adhesive tape is weak.

Therefore, conventionally, as a method for producing an adhesive tape, a monomer of a photoreactive composition is applied to a peelable film, and the photoreactive composition is photopolymerized to eliminate the solvent. An optical IN-SITU polymerization method has been proposed. For example, JP-A-60-139774
The publication describes a method for producing a pressure-sensitive adhesive transfer tape (double-sided tape) by adding a monofilament to a photoreactive composition and photopolymerizing it.

Further, such a double-sided tape is usually wound with a peelable film, and the peelable film must be peeled off before use, which is troublesome. Therefore, as a double-sided tape without this peelable film, for example, one shown in JP-A-59-193976 has been proposed. That is, in this double-sided tape, the first syrup partially polymerized in advance is applied to a plastic film, a flexible support is placed on the first syrup, and the thickness of the first syrup is made constant through the first knife. Two syrups are applied, covered with a plastic film and passed through a second knife to make the two syrup layers uniform in thickness. Then, after irradiating ultraviolet rays from both sides to complete the photopolymerization, the plastic film was peeled off, and only the double-sided tape having no plastic film was wound into a product. That is, this double-sided tape realizes a double-sided tape without a release film by utilizing photopolymerization and containing almost no solvent or residual monomer that causes delamination or set-off of the pressure-sensitive adhesive layer. It was done.

[0008]

However, in the case of the above-mentioned conventional production method by photopolymerization, the following inconvenience occurs. That is, in the case of the production method disclosed in JP-A-60-139774, the photoreactive composition coated on the peelable film is usually used to avoid reaction inhibition by oxygen.
Although photopolymerization occurs in an inert gas atmosphere, the interface with the inert gas atmosphere suffers from adverse effects such as monomer evaporation, which causes a problem that the cohesive force decreases.

Further, as disclosed in JP-A-59-193976, in the case of a method for producing a double-sided tape having no peelable film, the two syrup layers are left in a partially polymerized state, and the two syrup layers are kept between the knives. The thickness cannot be stabilized because it is adjusted by passing the syrup layer, and the syrup layer may have different thicknesses or may vary, which causes a problem that a high-performance double-sided tape cannot be manufactured stably. Become.

The present invention has been made in view of the above circumstances, and when a double-sided tape is produced by photopolymerization in an inert gas atmosphere, a double-sided tape that does not cause deterioration of the adhesive performance of the adhesive surface of the double-sided tape is produced. And a method for producing a double-sided tape having a stable thickness without a release substrate.

[0011]

In the method for producing a double-sided tape of the present invention for solving the above-mentioned problems, two release base materials each having a releasable surface are mainly composed of an acrylic ester. After coating the photoreactive composition, by light irradiation,
Up to 98% by weight of all the monomers in these photoreactive compositions are partially polymerized to form a partially polymerized tape, a flexible base material is sandwiched between the partially polymerized tapes, the partially polymerized tapes are pasted together, and then the partially polymerized tape is polymerized. Is completed.

Further, two release base materials each having a releasable surface are coated with a photoreactive composition containing an acrylic ester as a main component, and then, by irradiating with light, these photoreactive compositions are prepared. Up to 98% by weight of all monomers are partially polymerized tapes, a flexible base material is sandwiched between the partially polymerized tapes, and the partially polymerized tapes are bonded to each other. Polymerization is completed in the state where only one side is peeled off or the release substrate is peeled off on both sides, and after completion, only the double-sided tape body with the release substrate peeled off on both sides is wound.

Further, in the above manufacturing method, the number of carbon atoms is 1.
At least one acrylate-based monomer 6 selected from the group consisting of acrylic acid alkyl esters and methacrylic acid alkyl esters having 14 to 14 alkyl groups
0 to 98 parts by weight, and 2 to 40 parts by weight of a vinyl-based monomer copolymerizable with the acrylate-based monomer, and 100 parts by weight of the monomer composition to 0.
A photoreactive composition containing 1 to 5 parts by weight of a photopolymerization initiator as a main component is used.

Among the photoreactive compositions used in the present invention,
The monomer main component is used for synthesizing a known photopolymerizable acrylic pressure-sensitive adhesive, and specifically selected from the group consisting of alkyl acrylates and alkyl methacrylates having an alkyl group having 1 to 14 carbon atoms. At least one acrylate-based monomer 60-98
It contains 2 parts by weight and 2 to 40 parts by weight of a vinyl monomer copolymerizable with the acrylate monomer.

As the acrylate-based monomer, an alkyl or methacrylic acid alkyl ester having an alkyl group having 1 to 14 carbon atoms, preferably 4 to 12 carbon atoms is used, and specific examples thereof include (meth) acrylic acid n.
-Butyl, 2-ethylhexyl (meth) acrylate,
Examples thereof include isooctyl (meth) acrylate and isononyl (meth) acrylate.

These may be used alone or in combination of two or more. Due to the balance between tackiness and cohesiveness, the homopolymer glass transition temperature is usually -50.
It is preferable to use an acrylic acid alkyl ester having a temperature of not higher than 0 ° C. as a main component and a (meth) acrylic acid ester having a lower alkyl group or the following vinyl-based monomer as a comonomer.

The vinyl-based monomer copolymerizable with the acrylate-based monomer has a polar group such as a carboxyl group or a medium-polar functional group to enhance the interfacial adhesion as a pressure-sensitive adhesive, while improving the adhesiveness. Those which do not contain an excessive polyfunctional unsaturated compound component which adversely affects and which have a low evaporation property are preferable. A substance having a high evaporation property is not preferable because it causes a difference in composition between the surface layer portion and the inside during photopolymerization and causes a deterioration in performance.

Carboxyethyl acrylate, ω-carboxypolycaprolactone monoacrylate, succinic acid monohydroxyethyl acrylate, 2-acryloxyethyl hexahydrophthalic acid, β-acryloxyethyl hydrogen succinic acid satisfying the above-mentioned quality requirements. There is a nate. Of the polar monomers listed above, carboxyethyl acrylate is particularly preferable because it not only satisfies the above-mentioned required performance but also has high polymerizability.
Other suitable monomers are acrylic acid, itaconic acid, vinylpyrrolidone, acryloylmorpholine, acrylamide, alkylaminoethyl (meth) acrylates and the like.

Further, in order to impart viscosity and to improve interfacial adhesion by introducing medium polarity into the polymer,
For example, vinyl monomers such as isobornyl acrylate, tetrahydrofurfuryl acrylate, polyethylene glycol acrylate, polypropylene glycol acrylate, fluorine acrylate, and silicon acrylate can also be used. However, the amount of the vinyl-based monomer added should be in the range of 2 to 20 parts by weight with respect to 100 parts by weight of the vinyl-based monomer described above. This is because the addition of more than this has a favorable effect on the adhesive strength, but increases the glass transition temperature of the pressure-sensitive adhesive and lowers the tackiness at low temperatures.

Among the photoreactive compositions used in the present invention,
Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl)
Ketone [Darocur 2959: Ciba Geigy]; α
-Hydroxy-α, α'-dimethyl-acetophenone [Darocur 1173: manufactured by Ciba Geigy]; acetophenone type such as methoxyacetophenone and 2,2-dimethoxy-2-phenylacetophenone; benzoin ether type such as benzoin ethyl ether and benzoin isopropyl ether A ketal system such as benzyl dimethyl ketal; and a monofunctional photopolymerization initiator such as a halogenated ketone, an acylphosphinoxide, and an acylphosphonate.

The preferred addition amount for the compounding is about 0.1 to 5 parts by weight with respect to 100 parts by weight of the monomer component. When the lamp intensity during light irradiation is constant, the molecular weight of the obtained polymer is inversely proportional to the square root of the amount of the initiator added. In other words, the target adhesive polymer molecular weight can be controlled by the amount of the photopolymerization initiator.

In the photopolymerizable composition of the present invention, in order to impart heat resistance and cohesive force at high temperature, it is preferable to add a polyfunctional vinyl compound as a crosslinking agent together with the above photopolymerization initiator. .

Examples of such crosslinking agents include hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth). Acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, other epoxy acrylate,
Examples include polyester acrylate and urethane acrylate.

When the cross-linking agent is contained in an amount of 5 parts by weight or less with respect to 100 parts by weight of the monomer component, a cross-linking bond is generated between polymer molecules in the course of the photopolymerization reaction, and the heat resistance of the viscoelastic product is increased. The property is improved. When the viscoelastic product is a double-sided tape, the cohesive force at high temperature is increased and the holding power at high temperature is improved.

The peeling resistance of the double-sided tape to an adherend having a curved surface mainly depends on the degree of crosslinking of the adhesive, and this performance is exhibited when the gel fraction is 70% or less.

Further, the peeling resistance to the load in the shearing direction in the high temperature region becomes high performance when the gel fraction of the adhesive is 50% or more.

Therefore, generally, the amount of the crosslinking agent added is blended and designed so that the gel fraction is at this level.

Of course, the gel fraction level to be designed may be different from the above case for a specific application.

In the present invention, a tackifying resin may be added to the photopolymerizable composition.

Examples of materials used here include rosin resins, modified rosin resins, terpene resins, terpene phenol resins, aromatic modified terpene resins, C ₅ and C ₉ petroleum resins, and coumarone resins.

Further, in the present invention, the photopolymerizable composition may be blended with a commonly used additive such as a thickener, a thixotropic agent, a filler and a filler.

Examples of the extender include calcium carbonate, titanium oxide, clay and the like.

As the filler, inorganic hollow bodies such as glass balun, alumina balun and ceramic baln; organic spherical bodies such as nylon beads, acrylic beads and silicon beads; organic hollow bodies such as vinylidene chloride, acrylic baln; polyester, rayon , Nylon and other monofilaments.

The release substrate used in the present invention is not particularly limited as long as it has releasability such that the partially polymerized photoreactive composition can be transferred to the flexible substrate.
Usually, paper having a releasable surface or polyethylene terephthalate can be used.

The flexible substrate used in the present invention is flexible enough to be rolled or unwound as a substrate for double-sided tape, and is not particularly limited as long as it is a film or sheet. Examples thereof include cloths, woven cloths, non-woven cloths, plastic films and sheets, and plastic foams. Also,
When transparency is required for this flexible substrate, a transparent plastic film such as polyethylene terephthalate, cellulose acetate, stretched polyolefin, polyvinyl chloride, polyester, rayon, acrylic, nylon,
It is preferable to use a sheet or a non-woven fabric. Furthermore, when transparency is not required for this flexible substrate,
Foam sheets such as polyethylene and polypropylene can be used.

Specific examples of the cloth used as the flexible base material include cotton cloth and soft cloth. Woven fabrics used as flexible substrates include vinylon, tetron,
Examples thereof include woven fabrics of nylon and polyolefin resin yarns. Examples of the nonwoven fabric used as the flexible substrate include vinylon, tetron, nylon, polyolefin, aromatic polyamide fiber and glass nonwoven fabric.

The plastic film and sheet used as the flexible substrate include cellophane, polyvinyl chloride, polyester, polyethylene, polypropylene, acetate, polyimide, fluororesin, polycarbonate, nylon, polyurethane, polybutylene, polyvinyl alcohol-acrylic. Examples include films and sheets such as resin of the series.

Further, as the plastic foam used as the flexible substrate, polyolefin such as polyethylene and polypropylene, rubber such as polystyrene, polyvinyl chloride, chloroprene and butyl, acrylic, E
Examples include VA, ABS, nylon, viscose sponge, urethane, phenol, urea, silicone, and epoxy foams.

Next, a method for producing a double-sided tape using the above photoreactive composition will be described.

First, as shown in FIG. 1, a photoreactive composition 11 is applied by a roll coater 2 to two release base materials 10 each having a releasable surface.

Next, each of these photoreactive compositions 11 is irradiated with light 3 to partially polymerize up to 98% by weight of all the monomers of the photoreactive composition 11 to partially polymerize the tape 12.
Then, the flexible base material 13 is sandwiched between the partially polymerized tapes 12 and the partially polymerized tapes 12 are stuck together, and then the polymerization is completed. At this time, if the monomer remains, it may cause odor or stain the adherend. Therefore, it is preferable that the polymerization is substantially completed at 99.5% or more.

As a method of completing the polymerization, when the flexible base material 13 is light-transmissive and any of the release base materials 10 is light-transmissive, the release base material 10 is directly used.
The surface may be irradiated with light. If the release base material 10 is not light-transmissive, one release base material 10 may be peeled off and light irradiation 3 may be performed from the exposed surface as shown in FIG. However, in this case, the flexible base material 13 to be inserted is
When the light is irradiated again 3 the light energy of the flexible substrate 1 is
It must have sufficient light transmission so that it can reach the photoreactive composition layer on the opposite side through the third layer. Further, when not using photopolymerization, the polymerization may be completed by means such as thermal polymerization.

The monomer conversion, which is the degree of partial polymerization, must be 98% by weight or less of the amount of vinyl compound in the stock solution. If the conversion is higher than 98% by weight, the partial polymerized tape 12 will not be bonded sufficiently.
In particular, between the partially polymerized photoreactive composition 11,
Since the flexible base material 13 is sandwiched, control of this partial polymerization rate becomes important, and at a conversion rate higher than 98% by weight, the anchor between the partially polymerized photoreactive composition 11 and the flexible base material 13 is obtained. Adhesive failure occurs due to low force, which is not preferable. When one mold release substrate 10 is peeled off and light irradiation 3 is performed as a method for completing the polymerization, it is preferable that the monomer conversion rate is 40% by weight or more of the vinyl compound amount of the stock solution. This is because if it is lower than this, it may be difficult to peel the release substrate 10 from the partially polymerized tape 12.

The type of lamp used for the light irradiation 3 is one that emits a light wavelength in the same region as the absorption wavelength of the photopolymerization initiator, and examples thereof include a low pressure mercury lamp, a medium pressure mercury lamp, and a high pressure mercury lamp. A mercury lamp, an ultra-high pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp, etc. are used. Among these, the ultra-high pressure mercury lamp efficiently emits light in the active wavelength region of the photopolymerization initiator, and has a short wavelength of light that reduces the viscoelastic properties of the resulting polymer by crosslinking and heat vaporizes the reaction composition. It is preferable because it does not emit much long-wavelength light.

Regarding the reaction efficiency, it is preferable to use a lamp having a wavelength light in the active wavelength region of the photoinitiator to be used, but in this respect, the chemical lamp emits light having a wavelength in the active wavelength region of the photoinitiator. It is effective.

The irradiation intensity of the photoreactive composition 11 by the above-mentioned lamp is a factor that influences the degree of polymerization of the obtained polymer and is appropriately controlled depending on the performance of the target product.
When a general cleavage type initiator having an acetophenone group is blended, the range is preferably 0.1 to 100 mW / cm ² .

The double-sided tape 1 thus obtained is
By utilizing photopolymerization, the double-sided tape 1 containing almost no solvent or residual monomer that causes delamination or set-off of the pressure-sensitive adhesive layer 14 can be obtained. Therefore, as shown in FIG. 1, the double-sided tape 1 is usually wound with the release base material 10 in a state where the release base material 10 is attached to one side of the pressure-sensitive adhesive layer 14 to be a commercial product. As shown in FIG. 2, after the release base material 10 is peeled off, the double-sided tape 1
Only the part of the pressure-sensitive adhesive layer 14 can be wound and commercialized.

When the adhesive layer 14 alone is wound and commercialized in this way, as shown in FIG. 3, the release base materials 10 on both sides are peeled off before the light irradiation 3 is performed again. Light irradiation 3 may be performed from both sides. In this case, neither the release base material 10 nor the flexible base material 13 needs to have optical transparency.

Further, the release base material 10 and the flexible base material 1
When both 3 are light-transmissive, the release base material 10 may be peeled off and the pressure-sensitive adhesive layer 14 alone may be wound after the second light irradiation 3.

The thickness of the double-sided tape 1 thus obtained can be manufactured from 50 μm to a maximum of 3000 μm.

The photoreactive composition 11 applied to the release substrate 10 may be the same, but different ones are applied to produce the double-sided tape 1 having different adhesive performances on both sides. You can also In particular, in the case of a double-sided tape having no release substrate 10 on any surface, it is effective to change the polymerization composition of each to change the adhesive performance of the adjoining surfaces.

[0052]

According to the tape manufacturing method of the present invention, the polymer structure defining the adhesive performance is already formed in the early stage of the photoreaction, which is partially polymerized. Therefore, a flexible base material is sandwiched between the surfaces of the polymerized tape, which was the contact interface in the inert gas atmosphere during the initial polymerization, and the partially polymerized tapes are bonded to each other, and then the polymerization is completed so that the contact interface with the inert gas atmosphere is increased. The non-stick surface can be manufactured as the adhesive surface of the double-sided tape.

Further, a double-sided tape having a stable thickness can be manufactured by laminating a partially polymerized tape formed on a release base material.

Furthermore, the steps from the application of the photoreactive composition to the production of the double-sided tape can be carried out continuously.

[0055]

EXAMPLES Examples according to the present invention and comparative examples to be compared with them will be shown below to clarify the reason why the present invention is excellent.

[0056]

Example 1 (1) Preparation of photoreactive composition 2-ethylhexyl acrylate 95 g, acrylic acid 5
g, Irgacure 184 (Ciba Geigy product name)
0.2 g, hexanediol diacrylate 0.05
g and acrylic rubber 3 g were mixed and stirred to obtain a photoreactive composition.

The viscosity measured by a B-type viscometer is 1000 cp
It was s. (2) Production of double-sided tape The above photoreactive composition was applied to a release paper having a releasable surface by a two-roll coater so as to have a thickness of 50 μm. Then, in order to remove the heat of polymerization, while contacting the above-mentioned release paper with a stainless plate whose surface temperature was controlled to 5 ° C., a chemical lamp was used as a light source in a nitrogen atmosphere having an oxygen concentration of 200 ppm at a light intensity of 8 mW / cm ² for 20 minutes. It was irradiated with light for a second to obtain a partially polymerized tape. The conversion rate of the obtained partially polymerized tape was 90% by weight. Partially polymerized tapes were produced on another line under the same conditions as above. Cellulose nonwoven fabric was sandwiched between these partially polymerized tapes and bonded together, and then the release paper of one of the partially polymerized tapes was peeled off, and a further 8
Oxygen concentration of 200 pp for 45 seconds with light intensity of mW / cm ^2.
Light was irradiated in a nitrogen atmosphere of m to obtain a double-sided tape. (3) Performance evaluation The SP adhesive strength and holding power of the obtained double-sided tape were measured according to JIS
It was measured according to Z 1528. However, the holding power is
It was measured at a temperature of 80 ° C.

As a result, the adhesive strength of the front surface of the double-sided tape to the stainless steel plate was 1800 g with a width of 25 mm, and the back surface was 1790 g, which were substantially the same. Further, the variation in the adhesive force between the samples was within ± 100 g. Furthermore, when the holding power at 80 ° C. was measured, both front and back were 1
The weight did not fall for more than 00 hours.

[0059]

Example 2 A double-sided tape was manufactured in the same manner as in Example 1 except that the release paper was coated with the photoreactive composition at a thickness of 500 μm, and the SP adhesive strength and holding power of the double-sided tape obtained were obtained. And were similarly measured.

As a result, the adhesive strength of the double-sided tape was 3500 g with a width of 25 mm on both sides, which was substantially the same on both sides. Also, the variation in adhesive strength between samples is ± 100.
It was within g. Furthermore, the holding power at 80 ° C. was such that the weight did not drop on both the front and back for 100 hours or more.

[0061]

Example 3 Both release papers of the partially polymerized tape were peeled off,
A double-sided tape was manufactured in the same manner as in Example 1 except that the release paper was peeled off and light was irradiated from both sides, and the SP adhesive strength and holding power of the obtained double-sided tape were measured in the same manner.

As a result, the adhesive strength of the double-sided tape was 1800 g with a width of 25 mm on both sides, which was substantially the same on both sides. Also, the variation in adhesive strength between samples is ± 100.
It was within g. Furthermore, the holding power at 80 ° C. was such that the weight did not drop on both the front and back for 100 hours or more.

[0063]

Example 4 Example 3 described above except that a polyethylene terephthalate film was used instead of the cellulose nonwoven fabric.
A double-sided tape was manufactured by the same method as described above, and the SP adhesive strength and holding power of the obtained double-sided tape were measured in the same manner.

As a result, the adhesive strength of the double-sided tape was 1900 g with a width of 25 mm on both sides, which was substantially the same on both sides. Also, the variation in adhesive strength between samples is ± 100.
It was within g. Furthermore, the holding power at 80 ° C. was such that the weight did not drop on both the front and back for 100 hours or more.

[0065]

[Example 5] A double-sided tape was produced in the same manner as in Example 3 except that an acrylic foam having a thickness of 1 mm was used instead of the cellulose nonwoven fabric, and the SP of the obtained double-sided tape was used.
The adhesive force and the holding force were measured in the same manner.

As a result, the adhesive strength of the double-sided tape was 4000 g with a width of 25 mm on both sides, which was substantially the same on both sides. Also, the variation in adhesive strength between samples is ± 200
It was within g. Furthermore, the holding power at 80 ° C. was such that the weight did not drop on both the front and back for 100 hours or more.

[0067]

Example 6 A double-sided tape was manufactured in the same manner as in Example 3 except that a polyethylene terephthalate film was used instead of the release paper, and the SP adhesive strength and holding power of the obtained double-sided tape were similarly measured. It was measured.

As a result, the adhesive strength of the double-sided tape was 2000 g with a width of 25 mm on both sides, which was substantially the same on both sides. Also, the variation in adhesive strength between samples is ± 100.
It was within g. Furthermore, the holding power at 80 ° C. was such that the weight did not drop on both the front and back for 100 hours or more.

[0069]

Example 7 87 g of 2-ethylhexyl acrylate,
8 g of N-vinylpyrrolidone, 5 g of acrylic acid, 0.2 g of Irgacure 184 (trade name, manufactured by Ciba Geigy), 0.05 g of hexanediol diacrylate, and 3 g of acrylic rubber were mixed and stirred to obtain a photoreactive composition.

The viscosity measured by a B-type viscometer is 1000 cp
It was s.

The above photoreactive composition was used as the photoreactive composition of the partially polymerized tape prepared in one line, and the photoreactive composition of Example 1 was used as the photoreactive composition of the partially polymerized tape prepared in the other line. A double-sided tape was produced by the same method as in Example 3 except that the double-sided tape was used, and the SP adhesive force and holding force of the obtained double-sided tape were measured in the same manner.

As a result, the adhesive strength of the double-sided tape is 25 mm.
The width was 1900 g and 1800 g, and the front and back sides were substantially the same. Also, the variation in adhesive strength between samples is ± 1
It was within 00 g. Furthermore, the holding power at 80 ° C. was such that the weight did not drop on both the front and back for 100 hours or more.

[0073]

[Comparative Example 1] A cellulose nonwoven fabric was laminated on a release paper having a releasable surface, and the same photoreactive composition as in Example 1 was further applied thereon with a two-roll coater to a thickness of 130 µm. In this state, a part of the photoreactive composition passes through the cellulose nonwoven fabric and penetrates between the cellulose nonwoven fabric and the release paper, and the photoreactive composition is applied to both surfaces of the cellulose nonwoven fabric. became.

Then, an oxygen concentration of 200 is applied to the coated surface.
7 with a light intensity of 8 mW / cm ² in a nitrogen atmosphere of ppm
It was irradiated with light for 5 seconds to obtain a double-sided tape. The SP adhesive force and holding power of the obtained double-sided tape were measured in the same manner as in Example 1.

As a result, the adhesive strength of the double-sided tape was 25 mm.
In terms of width, there was a large difference between the front surface side of 2000 g and the back surface side of 1200 g, and the fluctuation rate of the adhesive force on the front surface side was as large as 40%.

Regarding the holding power at 80 ° C., the weight did not drop on the back surface even after 100 hours or more, whereas the weight dropped on the surface after 10 hours or less.

[0077]

As described above, according to the present invention, the surface which was not the contact interface with the inert gas atmosphere during the initial polymerization can be manufactured as the adhesive surface of the double-sided tape, and thus the double-sided tape having excellent adhesiveness can be obtained. You can get a tape.

Further, since a double-sided tape having a stable thickness can be manufactured by laminating a partially polymerized tape formed on a release-side base material, a high-performance double-sided tape having no release-side base material in particular. Can be stably manufactured.

Furthermore, since the steps from the coating of the photoreactive composition to the production of the double-sided tape can be carried out continuously, the double-sided tape can be produced efficiently.

[Brief description of drawings]

FIG. 1 is a manufacturing line diagram illustrating an example of a method for manufacturing a double-sided tape.

FIG. 2 is a manufacturing line diagram showing another embodiment of the method for manufacturing a double-sided tape.

FIG. 3 is a manufacturing line diagram showing still another embodiment of the method for manufacturing a double-sided tape.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Double-sided tape 10 Release base material 11 Photoreactive composition 12 Partially polymerized tape 13 Flexible base material 14 Adhesive layer (double-sided tape body) 3 Light irradiation

Claims (3)

[Claims] 1. A photoreactive composition containing an acrylic ester as a main component is applied to two release base materials each having a releasable surface, and then the photoreactive composition is exposed to light to form a photoreactive composition. Up to 98% by weight of all monomers are partially polymerized to form a partially polymerized tape, a flexible base material is sandwiched between the partially polymerized tapes, the partially polymerized tapes are bonded, and then the polymerization is completed. Double-sided tape manufacturing method. 2. A photoreactive composition containing an acrylic ester as a main component is applied to two release base materials each having a releasable surface, and then the photoreactive composition is exposed to light to form a photoreactive composition. Up to 98% by weight of all monomers are partially polymerized tapes, a flexible base material is sandwiched between the partially polymerized tapes, and the partially polymerized tapes are bonded to each other. The double-sided tape is characterized in that the polymerization is completed with only one side peeled off or with the release base material removed on both sides, and after completion, only the main body of the double-sided tape with the release base material removed on both sides is wound. Manufacturing method. 3. A photoreactive composition comprising 60 to 98 parts by weight of at least one acrylate-based monomer selected from the group consisting of alkyl acrylate and alkyl methacrylate having an alkyl group having 1 to 14 carbon atoms. And 2 to 40 parts by weight of a vinyl-based monomer copolymerizable with the acrylate-based monomer, and 0.1 to 5 parts by weight of a photopolymerization initiator per 100 parts by weight of the monomer composition. The method for producing the double-sided tape according to claim 1 or 2, which is contained as a component.